RU2813541C1 - Spiro compounds as antagonists of melanocortin 4 receptors and their use - Google Patents

Abstract

FIELD: pharmaceuticals.

SUBSTANCE: invention relates to a compound of formula I, where R¹, R², R³, X¹, Y¹, Y², Y³, Y⁴ and Y₅ have the meanings defined in this use, and a pharmaceutically acceptable salt thereof, as antagonist of MC4R. Pharmaceutical compositions containing such compounds and salts, and the use of such compounds and salts for the treatment of, for example, cachexia, anorexia or anorexia nervosa are also provided.

EFFECT: obtaining spiro compounds as antagonists of melanocortin 4 receptors and their use.

20 cl, 6 dwg, 14 tbl, 201 ex

Description

Field of technology to which the invention relates

The present invention relates to new pharmaceutical compounds, pharmaceutical compositions containing such compounds, and the use of the compounds as melanocortin 4 receptor (MC4R) antagonists.

Prerequisites for creating the invention

Melanocortins are peptides derived from proopiomelanocortins (POMCs) that bind to and activate G protein-coupled receptors (GPCRs) of the melanocortin receptor family. Melanocortins regulate a wide range of physiological processes, including sexual function and behavior, food intake and metabolism. To date, five melanocortin receptors (MCRs) have been identified in mammals: MC1R, MC2R, MC3R, MC4R and MC5R, which are expressed in various tissues. MC1R is specifically expressed in melanocytes and melanoma cells, MC2R is an ACTH receptor and is expressed in adrenal tissue, MC3R is predominantly expressed in the brain and limbic system, MC4R is widely expressed in the brain and spinal cord, and MC5R is expressed in the brain and many peripheral tissues. including skin, adipose tissue, skeletal muscle and lymphoid tissue. See, for example, US Pat. No. 8,138,188 and Saleh et al., Front. Pharmacol., 2018, 9:560.

MC4R is a G protein-coupled seven-transmembrane receptor predominantly expressed in the hypothalamus, hippocampus and thalamus (Gantz et al. 1993 J. Biol. Chem. 2 68:15174-15179). The receptor is involved in the central regulation of body weight: MC4R is activated by α-melanocyte-stimulating hormone (MSH), which is formed from proopiomelanocortin and inactivated by agouti-related protein (AGRP). α-MSH causes weight loss, whereas ectopic expression of agouti protein leads to obesity in agouti mice (Fan et al. 1993 Nature 385:165-168; Lu et al. 1994 Nature 371:799-802). Additional evidence for a role for MC4R in body weight regulation comes from a knockout model in mice (Huszar et al. 1997 Cell 88:131–141) as well as from haploinsufficiency mutations in humans (Vaisse et al. 1998 Nat. Genet. 20 :113-114; Yeo et al. 1998 Nat. Genet. 20:111-112; Hinney et al. 1999 J. Clin. Endocrinol. Metab. 8 4:1483-1486). In MC4R knockout mice, body weight gain was noticeable by 5 weeks of age. By 15 weeks of age, homozygous mutant females were on average twice as heavy as their wild-type littermates, whereas homozygous mutant males were ∼50% heavier than wild-type controls. MC4R knockout heterozygous mice showed body weight gains intermediate to those observed in wild-type and homozygous mutant littermates, thus demonstrating a dose effect of MC4R ablation on body weight regulation. Food intake of homozygous mutants was increased by ~50% compared with wild-type siblings (Huszar et al. 1997 Cell 88:131-141). [From Am. J.Hum. Genet., 65:1501-1507,1999]. Activation of MC4R has been shown to induce penile erection in rodents, and inactivation of MC4R has been shown to cause obesity (see Hadley, 1999, Ann. NY Acad. Sci., 885:1-21; Wikberg et al. 2000, Pharmacol. Res., 42(5), 393-420; and Saleh et al., Front. Pharmacol., 2018, 9:560).

In recent years, several types of small molecule MC4R antagonists have been reported in the literature and patent applications [see, for example, WO 2010052256; WO 2010081666; US Patent No. 8,044,068; Chaki et al., Current Topics in Medicinal Chemistry, 2007, 7, 1145-1151; Foster et al., Current Topics in Medicinal Chemistry, 2007, 7, 1131-1136; Pontillo et al., Bioorganic & Medicinal Chemistry Letters 15 (2005) 2541-46; Vos et al., Bioorganic & Medicinal Chemistry Letters 16(2006) 2302-2305; Tao, Endocrine Reviews, 2010, 31(4):506-543; and Saleh et al., Front. Pharmacol., 2018, 9: 560]. These MC4R antagonists are useful for the treatment and/or prevention of MC4R-related conditions, diseases or disorders, such as cachexia [including, for example, cachexia associated with chronic disease, such as cachexia associated with cancer, cachexia associated with acquired immunodeficiency syndrome (AIDS) ), cachexia associated with heart failure, such as cachexia associated with congestive heart failure (CHF), cachexia associated with chronic kidney disease (CKD); cachexia associated with the treatment of a chronic disease, such as cachexia associated with the treatment of cancer or cachexia associated with the treatment of heart failure (eg, CHF)]; anorexia or anorexia nervosa (eg, anorexia in the elderly, anorexia associated with chemotherapy and/or radiation therapy); nausea; vomiting; weight loss (eg, unintentional weight loss); developmental delays; sarcopenia; muscle atrophy; muscle weakness; weakness; osteoporosis; bone diseases (eg, bone loss); pain; neuropathic pain; anxiety (such as post-traumatic stress disorder, or PTSD); depression; hypertension; eating disorders; obesity (eg, sarcopenia due to chronic obesity); sexual dysfunction; and an inflammatory disease (eg, an inflammatory disease associated with anorexia, or cachexia, or sarcopenia, or muscle wasting).

There continues to be a need for alternative MC4R antagonists, for example, for the development of new and/or improved pharmaceuticals (e.g., more effective, more selective, less toxic and/or having improved biopharmaceutical properties such as physical stability, solubility, oral bioavailability; appropriate metabolic stability; clearance; half-life) for the treatment or prevention of MC4R-related conditions, diseases or disorders such as those described herein. The present invention is directed to these and other important purposes.

The essence of the invention

In one embodiment (Embodiment A1), the present invention provides a compound of formula I:

or a pharmaceutically acceptable salt thereof, where:

R ¹ is H, halogen, C _1-4 alkyl, C _1-4 haloalkyl, C _3-6 cycloalkyl, 4-7 membered heterocycloalkyl, phenyl, or R ^1a , where each of C _3-6 cycloalkyl and 4-7 -membered heterocycloalkyl is optionally substituted with 1, 2, 3 or 4 independently selected C _1-4 alkyl groups, and wherein phenyl is optionally substituted with 1, 2, 3 or 4 independently selected ^RB groups, wherein each ^RB is halogen, -OH, -CN, alkyl, haloalkyl, alkoxy, C _1-4 haloalkoxy, C _3-4 cycloalkyl or ^RB1 , or two adjacent ^RB together with the two ring-forming phenyl atoms to which they are attached form a fused 5- or 6-membered heteroaryl, each of which is optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -ON, alkyl, haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy;

R ^1a is a 5- or 6-membered heteroaryl, optionally substituted with 1, 2, 3 or 4 independently selected R ^A groups, where each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _{1- 4} haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy, C _3-4 cycloalkyl, -N (C _1-4 alkyl) 2, R ^A1 or (C _3-4 cycloalkyl) -C _1-4 alkyl-, wherein each of _C1-4 alkyl, _C3-4 cycloalkyl and ( _C3-4 cycloalkyl) _-C1-4 alkyl- is optionally substituted with 1, 2, 3, 4 or 5 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy; or two adjacent R ^A together with the two ring-forming 5- or 6-membered heteroaryl atoms to which they are attached form a fused benzene ring, or a fused 5- or 6-membered heteroaryl, or a fused 5- or 6-membered heterocycloalkyl, or fused 5- or 6-membered cycloalkyl, each of which is optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _{1- 4} alkoxy and C _1-4 haloalkoxy;

R ^A1 is a 5- or 6-membered heteroaryl or a 5- or 6-membered heterocycloalkyl, each of which is optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -CN, alkyl, haloalkyl, alkoxy and _Cl-4 haloalkoxy;

R ^B1 is a 5- or 6-membered heteroaryl, each of which is optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -CN, alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy;

X ¹ represents C(R ^X ) ₂ where each R ^X independently represents H or C _1-4 alkyl;

each of R ² and R ³ independently represents H, halogen, C _1-4 alkyl, C _1-4 hydroxyalkyl, C _1-4 haloalkyl, (C _1-4 alkoxy)-C _1-4 alkyl-, C _{3- 4} cycloalkyl or (C _3-4 cycloalkyl)-C _1-4 alkyl, wherein each of the C _3-4 cycloalkyl and (C _3-4 cycloalkyl)-C _1-4 alkyl is optionally substituted with 1, 2, 3, 4 or 5 substituents, each independently selected from halogen, -OH, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy;

or R ² and R ³ together with the carbon atom to which they are bonded form a C _3-6 cycloalkyl, optionally substituted with 1, 2, 3, 4 or

5 substituents, each independently selected from halogen, -OH, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy;

each of Y ¹ , Y ² , Y ³ , Y ⁴ , and Y ⁵ is independently CR ⁴ or N, provided that no more than 3 of Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ are N; And

each R ⁴ independently represents H, halogen, -OH, CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy, -N(C _1-2 alkyl) ₂ , C _3-4 cycloalkyl or (C _3-4 cycloalkyl)-C _1-4 alkyl-, where each of C _1-4 alkyl, C _3-4 cycloalkyl and (C _3-4 cycloalkyl)-C _1-4 alkyl- optionally substituted with 1, 2, 3, 4 or 5 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy .

The present invention also provides a pharmaceutical composition containing a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt of such a compound and a pharmaceutically acceptable carrier.

The present invention also provides a method for treating an MC4R-related condition, disease or disorder in a mammal (eg, a human) in need of such treatment, the method comprising administering to the mammal (eg, a human) a compound of Formula I or a pharmaceutically acceptable salt of such a compound.

The present invention also provides a compound of formula I or a pharmaceutically acceptable salt of such a compound for use in the treatment of an MC4R-related condition, disease or disorder.

An MC4R-related condition, disease or disorder includes one selected from cachexia [including, for example, cachexia associated with a chronic disease such as cachexia associated with cancer, cachexia associated with acquired immunodeficiency syndrome (AIDS), cachexia associated with heart failure, eg cachexia associated with congestive heart failure (CHF), cachexia associated with chronic kidney disease (CKD); cachexia associated with the treatment of a chronic disease, such as cachexia associated with the treatment of cancer or cachexia associated with the treatment of heart failure (eg, CHF)]; anorexia or anorexia nervosa (eg, anorexia in the elderly, anorexia associated with chemotherapy and/or radiation therapy); nausea; vomiting; weight loss (eg, unintentional weight loss); developmental delays; sarcopenia; muscle atrophy; muscle weakness [eg, muscle weakness associated with chronic obstructive pulmonary disease (COPD)]; weakness; osteoporosis; bone diseases (eg, bone loss); pain; neuropathic pain; anxiety (such as post-traumatic stress disorder, or PTSD); depression; hypertension; eating disorders; obesity (eg, sarcopenia due to chronic obesity); sexual dysfunction; and an inflammatory disease (eg, an inflammatory disease associated with anorexia, or cachexia, or sarcopenia, or muscle wasting).

The present invention also provides a method for treating a condition, disease or disorder in a mammal (eg, human) in need of such treatment, the method comprising administering to the mammal (eg, human) a compound of Formula I or a pharmaceutically acceptable salt of such compound, wherein the condition, disease or the disorder is selected from cachexia [including, for example, cachexia associated with a chronic disease, such as cachexia associated with cancer, cachexia associated with acquired immunodeficiency syndrome (AIDS), cachexia associated with heart failure, such as cachexia associated with congestive heart disease failure (CHF), cachexia associated with chronic kidney disease (CKD); cachexia associated with the treatment of a chronic disease, such as cachexia associated with the treatment of cancer or cachexia associated with the treatment of heart failure (eg, CHF)]; anorexia or anorexia nervosa (eg, anorexia in the elderly, anorexia associated with chemotherapy and/or radiation therapy); nausea; vomiting; weight loss (eg, unintentional weight loss); developmental delays; sarcopenia; muscle atrophy; muscle weakness; weakness; osteoporosis; bone diseases (eg, bone loss); pain; neuropathic pain; anxiety (such as post-traumatic stress disorder, or PTSD); depression; hypertension; eating disorders; obesity (eg, sarcopenia due to chronic obesity); sexual dysfunction; and an inflammatory disease (eg, an inflammatory disease associated with anorexia, or cachexia, or sarcopenia, or muscle wasting).

The present invention also provides a method of antagonizing the melanocortin-4 receptor (MC4R), the method comprising contacting the MC4R with a compound of formula I or a pharmaceutically acceptable salt of such a compound.

It should be understood that both the above general description and the following detailed description are presented for illustration and explanation only and not as a limitation of the claimed invention.

Brief description of drawings

Fig. 1 shows an exemplary single crystal structure of the compound of Example 14.

Fig. 2 shows an exemplary single crystal structure of the compound of Example 15.

Fig. 3 shows a representative X-ray powder diffraction pattern of crystalline form P23 observed.

Fig. 4 shows a representative X-ray powder diffraction pattern of the C69 crystalline form observed.

Fig. 5 shows a representative X-ray powder diffraction pattern of crystalline form P28 observed.

Fig. 6 shows a representative X-ray powder diffraction pattern of the crystalline form of Example 14 observed.

Detailed Description of the Invention

The present invention will be better understood by reference to the following detailed description of illustrative embodiments of the invention and examples included therein.

It should be understood that the present invention is not limited to specific methods of production by synthesis, which, of course, may vary. It should also be understood that the terminology used in this application is intended to describe only specific embodiments and is not intended to be limiting. In the present specification and the following claims, a number of terms are used which are to be defined as having the following meanings:

As used in the description of the present invention, singular forms can mean "one or more." As used in the claims, when used in conjunction with the word “including,” the singular forms can mean “one or more than one.” As used herein, "other" can mean at least "another one or more."

The term "about" refers to a relative term meaning a value close to the specified value, within plus or minus 10% of the specified value to which the term refers, in one embodiment meaning plus or minus 5%, in another embodiment means plus or minus 2%. For the scope of the present invention, this level of approximation is appropriate unless it is specifically stated that narrower limits of value are required.

"Compound" as used herein includes any pharmaceutically acceptable derivative or variant, including conformational isomers (e.g., cis and trans isomers) and all optical isomers (e.g., enantiomers and diastereomers), racemic, diastereomeric and other mixtures of such isomers, as well as solvates , hydrates, isomorphs, polymorphs, tautomers, esters, salt forms and prodrugs. The expression "prodrug" refers to compounds that are precursors to drugs that, after administration, release the drug in vivo as a result of some chemical or physiological process (for example,

the prodrug is converted to the desired drug form under physiological pH conditions or by the action of an enzyme).

The term "alkyl" means an acyclic saturated aliphatic hydrocarbon group, which may be straight chain/linear or branched. Examples of such groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, butyl, sec-butyl, isobutyl and tert-butyl. The number of carbon atoms in alkyl and other various hydrocarbon-containing groups is indicated by a prefix indicating the lower and upper limit of the number of carbon atoms in the group, i.e. the prefix C _ij means a group with a number of carbon atoms from the integer "i" to the integer "j", inclusive. Thus, for example, alkyl refers to an alkyl containing from one to four carbon atoms, inclusive. Representative examples of alkyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. As another example, alkyl refers to an alkyl containing from one to two carbon atoms, inclusive (ie, methyl or ethyl). The alkyl group may optionally be substituted with 1 or more (eg 1-5) suitable substituents, if indicated.

At various places herein, substituents of the compounds of the invention are disclosed as groups or ranges. In particular, the invention is intended to include each distinct subcombination of members of such groups and ranges. For example, the term "C _1-4 alkyl" is specifically intended to include C ₁ alkyl (methyl), C ₂ alkyl (ethyl), C ₃ alkyl and C ₄ alkyl. In another example, the term "4- to 7-membered heterocycloalkyl" is specifically intended to include any 4-, 5-, 6-, or 7-membered heterocycloalkyl group.

As used herein, the term "n-membered", where n is an integer, generally describes the number of ring-forming atoms in a group where the number of ring-forming atoms is n. For example, pyridinyl is an example of a 6-membered heteroaryl ring, and pyrazolyl is an example 5-membered heteroaryl group.

As used herein, the term "alkoxy" or "alkyloxy" refers to an -O-alkyl group. For example, the term "C _1-4 alkoxy" or alkyloxy" refers to the group -O-(C _1-4 alkyl); as another example, the term "C _1-2 alkoxy" or "C _1-2 alkyloxy" refers to -O-(C _1-2 alkyl) group. Examples of alkoxy include methoxy, ethoxy, propoxy (for example, n-propoxy and isopropoxy), t-butoxy, etc. The alkoxy or alkyloxy group may optionally be substituted by 1 or more ( for example, 1-5) suitable substituents, if indicated.

The term "halo" or "halogen" as used herein means -F, -Cl, -Br or -I.

As used herein, the term “haloalkyl” refers to an alkyl group containing one or more halogen substituents (up to perhaloalkyl, ie, each hydrogen atom of the alkyl group is replaced by a halogen atom). For example, the term "haloalkyl" refers to a C _1-4 alkyl group containing one or more halogen substituents (up to perhaloalkyl, i.e., each hydrogen atom of the alkyl group is replaced by a halogen atom); and the term "C _1-2 haloalkyl" refers to With a _1-2 alkyl group (i.e. methyl or ethyl) containing one or more halogen substituents (up to perhaloalkyl, i.e. each hydrogen atom of the alkyl group is replaced by a halogen atom).Examples of haloalkyl groups include -CF ₃ , - CHF ₂ , -CH ₂ F, -CH ₂ CF ₃ , -C ₂ F ₅ , -CH ₂ Cl, etc.

"Fluoroalkyl" means alkyl, as defined above, substituted with one or more fluoro(-F)-substituents (up to perfluoroalkyl, ie, each hydrogen atom of the alkyl group is replaced by a fluorine atom). The term "C _1-2 fluoroalkyl" refers to a C _1-2 alkyl group (i.e., methyl or ethyl) containing one or more fluorine substituents (up to perfluoroalkyl, i.e., each hydrogen atom of the alkyl group is replaced by a fluorine atom ); and the term "C ₁ fluoroalkyl" refers to methyl containing 1, 2 or 3 fluoro substituents. Examples of C ₁ fluoroalkyl include fluoromethyl, difluoromethyl and trifluoromethyl; some examples of C ₂ fluoroalkyl include 1-fluoroethyl, 2-fluoroethyl, 2,2-difluoroethyl, 1,2-difluoroethyl, 2,2,2-trifluoroethyl, 1,1,2-trifluoroethyl and the like.

As used herein, the term "haloalkoxy" refers to an -O-haloalkyl group. For example, the term "C _1-4 haloalkoxy" refers to the group -O-(C _1-4 haloalkyl); and the term "C _1-2 haloalkoxy" refers to the group -O-(C _1-2 haloalkyl). As another example, the term "C ₁ haloalkoxy" refers to a methoxy group containing one, two or three halogen substituents. An example of haloalkoxy is -OCF ₃ or -OCHF ₂ .

As used herein, the term "fluoroalkoxy" refers to an -O-fluoroalkyl group. For example, the term "C _1-2 fluoroalkoxy" refers to the group -O-(C _1-2 fluoroalkyl); and the term "C _1-2 fluoroalkoxy" refers to the -O-(C ₁ fluoroalkyl) group. Examples of C ₁ fluoroalkoxy include -O-CH ₂ F, -O-CHF ₂ and -O-CF ₃ . Some examples of C ₂ fluoroalkoxy include -O-CH ₂ CHF ₂ , -O-CH ₂ -CHF ₂ , -O-CH ₂ CF ₃ , -O-CF ₂ CH ₃ and -O-CF ₂ CF ₃ .

As used herein, the term “hydroxylalkyl” or “hydroxyalkyl” refers to an alkyl group containing one or more (eg, 1, 2 or 3) OH substituents. The term “C _1-4 hydroxyalkyl” or “C _1-4 hydroxyalkyl” refers to a C _1-4 alkyl group containing one or more (eg, 1, 2 or 3) OH substituents; and the term "C _1-2 hydroxyalkyl" or "C _1-2 hydroxyalkyl" refers to a C _1-2 alkyl group containing one or more (eg, 1, 2 or 3) OH substituents. An example of hydroxyalkyl is -CH ₂ OH or -CH ₂ CH ₂ OH.

As used herein, the term "cycloalkyl" refers to saturated or unsaturated non-aromatic monocyclic or polycyclic (such as bicyclic) hydrocarbon rings (e.g., monocyclic, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, or bicyclic, including spiro , fused or bridged systems (such as bicyclo[1.1.1]pentanyl, bicyclo[2.2.1]heptanyl, bicyclo[3.2.1]octanyl or bicyclo[5.2.O]nonanyl, decahydronaphthalenyl, etc.).

A cycloalkyl group contains 3-15 (eg 3-14, 3-10, 3-6, 3-4 or 4-6) carbon atoms. In some embodiments, the cycloalkyl may optionally contain one, two or more non-cumulative non-aromatic double or triple bonds and/or one to three oxo groups. In some embodiments, the bicycloalkyl group contains from 6 to 14 carbon atoms. The term "C _3-4 cycloalkyl" as used herein means a saturated cyclic hydrocarbon group containing from 3 to 4 carbon atoms. Examples of C _3-4 cycloalkyl include cyclopropyl and cyclobutyl. Also included in the definition of cycloalkyl are groups that contain one or more aromatic rings (including aryl and heteroaryl) fused to a cycloalkyl ring, such as benzo or pyridinyl derivatives of cyclopentane (5-membered cycloalkyl), cyclopentene, cyclohexane (6-membered cycloalkyl), and the like, for example 6,7-dihydro-5H-cyclopenta[b]pyridinyl, 5, 6,7,8-tetrahydroquinolinyl or 1 5,6,7,8-tetrahydroisoquinolinyl, each of which includes a 5-membered or a 6-membered cycloalkyl group that is fused to a heteroaryl ring (ie, a pyridinyl ring). The cycloalkyl or C _3-4 cycloalkyl group may optionally be substituted with 1 or more (eg 1-5) suitable substituents, if indicated.

The term "C _3-4 cycloalkyl-C _1-4 alkyl-" as used herein means a C _3-4 cycloalkyl as defined herein attached to the parent molecular group via a C _3-4 alkyl group as defined herein. Some examples of the C _3-4 cycloalkyl-C _1-4 alkyl group include cyclopropylmethyl, 2-cyclopropylethyl, 2-cyclopropylpropyl, 3-cyclopropylpropyl, cyclobutylmethyl, 2-cyclobutylethyl, 2-cyclobutylpropyl and 3-cyclobutylpropyl.

As used herein, the term "heterocycloalkyl" refers to a monocyclic or polycyclic [including 2 or more rings that are fused together, including spiro, fused or bridged systems, e.g., a bicyclic ring system] saturated or unsaturated non-aromatic 4-15 membered ring system system (such as 4-14 member ring system, 4-12 member ring system, 5-10 member ring system, 4-7 member ring system, 4-6 member ring system or 5-6 member ring system system) comprising 1-14 ring-forming carbon atoms and 1-10 ring-forming heteroatoms, each independently selected from O, S and N (and optionally P or B, if present). The heterocycloalkyl group may also optionally contain one or more oxo (ie =O) or thiono (ie =S) groups. For example, the term "4-7 membered heterocycloalkyl" refers to a monocyclic or polycyclic, saturated or unsaturated, non-aromatic 4-7 membered ring system that includes one or more ring-forming heteroatoms, each independently selected from O, S and N As another example, the term "5- or 6-membered heterocycloalkyl" refers to a monocyclic or polycyclic, saturated or unsaturated, non-aromatic 5- or 6-membered ring system that includes one or more ring-forming heteroatoms, each independently selected from O, S and N. The heterocycloalkyl group may optionally be substituted with 1 or more (eg 1-5) suitable substituents when indicated.

Some examples of 4-7 membered heterocycloalkyl include azetidinyl, oxetanyl, tetrahydrofuranyl, imidazolidinyl, pyrrolidinyl, piperidinyl, piperazinyl, oxazolidinyl, thiazolidinyl, pyrazolidinyl, thiomorpholinyl, tetrahydrothiazinyl, tetrahydrothiadiazinyl, morpholinyl, tetrahydrodiazinyl, and others. trahydropyranil (also known as oxanyl). Some other examples of 4-7-heterocycloalkyl include tetrahydrofuran-2-yl, tetrahydrofuran-3-yl, tetrahydropyranyl (e.g., tetrahydro-2H-pyran-4-yl), imidazolidin-1-yl, imidazolidin-2-yl, imidazolidin- 4-yl, pyrrolidin-1-yl, pyrrolidin-2-yl, pyrrolidin-3-yl, piperidin-1-yl, piperidin-2-yl, piperidin-3-yl, piperidin-4-yl, piperazin-1- yl, piperazin-2-yl, 1, 3-oxazolidin-3-yl, 1,4-oxazepan-2-yl, isothiazolidinyl, 1, 3-thiazolidin-3-yl, 1,2-pyrazolidin-2-yl, 1,2-tetrahydrothiazin-2-yl, 1,3-thiazinan-3-yl, 1,2-tetrahydrodiazin-2-yl, 1,3-tetrahydrodiazin-1-yl, 1,4-oxazin-4-yl, oxazolidinonyl, 2-oxo-piperidinyl (for example, 2-oxo-piperidin-1-yl), 2-oxoazepan-3-yl, etc.

As used herein, the term “heteroaryl” refers to monocyclic or fused polycyclic aromatic heterocyclic groups with one or more heteroatoms as ring members (ring-forming atoms), each independently selected from O, S and N, in at least one ring . The heteroaryl group contains 5-14 ring-forming atoms, including 1-13 carbon atoms and 1-8 heteroatoms selected from O, S, and N. In some embodiments, the heteroaryl group contains 5-10 ring-forming atoms, including from one to four heteroatoms. Heteroaryl groups may also contain one to three oxo or thiono (ie =S) groups. In some embodiments, the heteroaryl group contains 5-8 ring-forming atoms, including one, two, or three heteroatoms. For example, the term “5-membered heteroaryl” refers to a monocyclic heteroaryl group as defined above with 5 ring-forming atoms on the monocyclic heteroaryl ring; the term "6-membered heteroaryl" refers to a monocyclic heteroaryl group as defined above with 6 ring-forming atoms on the monocyclic heteroaryl ring; and the term “5- or 6-membered heteroaryl” refers to a monocyclic heteroaryl group as defined above with 5 or 6 ring-forming atoms on the monocyclic heteroaryl ring. The heteroaryl group may optionally be substituted with 1 or more (eg 1-5) suitable substituents when indicated. Examples of monocyclic heteroaryls include groups with 5 ring-forming atoms, including one to three heteroatoms, or groups with 6 ring-forming atoms, including one, two or three nitrogen heteroatoms. Examples of fused bicyclic heteroaryls include two fused 5- and/or 6-membered monocyclic rings containing from one to four heteroatoms.

Some examples of heteroaryl groups include pyridinyl (for example, pyridin-2-yl, pyridin-3-yl, pyridin-4-yl), pyrazinyl, pyrimidinyl (for example, pyrimidin-2-yl, pyrimidin-4-yl or pyrimidin-5- yl), pyridazinyl (e.g. pyridazin-3-yl or pyridazin-4-yl), thienyl, furyl, imidazolyl (e.g. 1H-imidazol-4-yl), pyrrolyl, oxazolyl (e.g. 1,3-oxazolyl, 1 , 2-oxazolyl), thiazolyl (e.g. 1,2-thiazolyl, 1,3-thiazolyl), pyrazolyl (e.g. pyrazol-1-yl, pyrazol-3-yl, pyrazol-4-yl), tetrazolyl (e.g. 2H-tetrazol-5-yl), triazolyl (e.g. 1,2,3-triazolyl, 1,2,4-triazolyl), oxadiazolyl (e.g. 1,2,3-oxadiazolyl, 1, 2, 4-oxadiazolyl or 1,3,4-oxadiazolyl), thiadiazolyl (e.g. 1,3,4-thiadiazolyl or 1,2,4-thiadiazolyl), quinolyl, isochnolyl, benzothienyl, benzofuryl, indolyl, benzothiazolyl, 1, 2-benzoxazolyl, 1H- imidazo[4,5-c]pyridinyl, imidazo[1,2-a]pyridinyl, 1H-pyrrolo[3,2-c]pyridinyl, imidazo[1,2-a]pyrazinyl, imidazo[2,1-e] [1,2,4]triazinyl, imidazo[1,5-a]pyrazinyl, imidazo[1,2-a]pyrimidinyl, 1H-indazolyl, 9H-purinyl, imidazo[1,2-a]pyrimidinyl, [1, 2,4]triazolo[1,5-a]pyridinyl, [1,2,4]triazolo[1,5-a]pyrimidinyl, [1,2,4]triazolo[4,3-b]pyridazinyl, isoxazolo[ 5,4-e]pyridazinyl, isoxazolo[3,4-e]pyridazinyl, pyrazolo[1,5-a]pyrimidinyl, 6,7-dihydro-5H-pyrrolo[1,2-b] [1,2,4 ]triazolyl, pyridone, pyrimidone, pyrazinone, pyrimidinone, 1H-imidazol-2(3H)-one, 1H-pyrrol-2,5-dione, 3-oxo-2H-pyridazinyl, 1H-2-oxo-pyrimidinyl, 1H- 2-oxo-pyridinyl, 2, 4 (1H, 3H)-dioxo-pyrimidinyl, 1H-2-oxo-pyrazinyl, etc.

As used herein, the compound of formula I described herein includes optional substitutions and variables. It should be understood that the normal valency of each of the indicated (optionally substituted) atoms or groups is not exceeded, and that any of the optional substitutions results in a stable compound. It should also be understood that combinations of optional substituents and/or variables are permissible only if such combinations result in a stable compound.

In the context of this application, unless otherwise indicated, the point of attachment of the substituent can be from any suitable position of the substituent. For example, piperidinyl may be piperidin-1-yl (attached via the N atom of piperidinyl), piperidin-2-yl (attached via the C atom at the 2-position of piperidinyl), piperidin-3-yl (attached via the C atom at the 3-position piperidinyl) or piperidin-4-yl (attached via the C atom at the 4-position of piperidinyl). As another example, pyridinyl (or pyridyl) may be 2-pyridinyl (or pyridin-2-yl), 3-pyridinyl (or pyridin-3-yl), or 4-pyridinyl (or pyridin-4-yl).

In the context of the present application, the point of attachment of a substituent can be defined to indicate the position where a substituent is attached to another group. For example, "(C _3-4 cycloalkyl)-C _1-4 alkyl-" means that the point of attachment is in the "C _1-4 alkyl" part of the group "(C _3-4 cycloalkyl)-C _1-4 alkyl-" .

When a substituted or optionally substituted group is described without specifying the atom through which such group is bonded to the substituent, then the substituent may be bonded through any suitable atom in such group. For example, in the substituted "(C _3-4 cycloalkyl)-C _1-4 alkyl-", the substituent is on the cycloalkylalkyl [i.e. (C _3-4 cycloalkyl) -C _1-4 alkyl-] may be bonded to any carbon atom of the alkyl moiety or cycloalkyl moiety of the cycloalkylalkyl. Combinations of substituents and/or variables are permitted only if such combinations result in stable compounds.

As used herein, the term “contiguous” when describing the relative positions of two groups of substituents on a ring structure refers to two groups of substituents that are respectively attached to two ring-forming atoms of the same ring, where the two ring-forming atoms are directly via a chemical bond. For example, in each of the following structures:

either of the two R ⁷⁰ groups is adjacent to the R ⁶⁰ group.

"Mammals" refer to warm-blooded vertebrate animals characterized by the secretion of milk by the female to nurse their young, such as guinea pigs, mice, rats, gerbils, cats, rabbits, dogs, cattle, goats, sheep, horses, monkeys, chimpanzees and humans.

The term "pharmaceutically acceptable" means a substance (eg, compounds of the invention) and any salt thereof or a composition containing a substance or salt of the invention that is suitable for administration to a patient.

As used herein, the expressions “reaction-inert solvent” and “inert solvent” refer to a solvent or mixture of solvents that does not react with the starting materials, reagents, intermediates or products so as to adversely affect the yield of the desired product.

As used herein, the term “selectivity” or “selective” refers to the greater effect of a compound in a first assay compared to the effect of the same compound in a second assay. For example, in “gut-selective” compounds, the first assay is designed to determine the half-life of the compound in the intestine, and the second assay is designed to determine the half-life of the compound in the liver.

"Therapeutically effective amount" means an amount of a compound of the present invention that (i) treats or prevents a particular disease, condition or

disorder; (ii) reduces, improves or eliminates one or more symptoms of a specific disease, condition or disorder; or (iii) prevents or delays the onset of one or more symptoms of a specific disease, condition or disorder described in this application.

The term “treat,” “treat,” or “cure,” as used herein, includes both preventive, i.e. prophylactic, and palliative treatment, including reversing the development, alleviating, reducing the severity, or slowing the progression of a disease (or disorder or condition) or any tissue damage associated with one or more symptoms of a disease (or disorder, or condition).

In the context of this application, the term "contacting" refers to the combination of these parts in an in vitro system or an in vivo system. For example, “contacting” MC4R with a compound of the invention includes administering a compound of the invention to a mammal, such as a human, having MC4R, as well as, for example, administering a compound of the invention to a sample containing a cell or purified preparation containing MC4R.

Embodiment A2 is a further embodiment of Embodiment A1, wherein the compound of formula I or a pharmaceutically acceptable salt thereof is a compound of formula Ia:

or a pharmaceutically acceptable salt thereof, and wherein the variables R ¹ , R ² , R ³ , X ¹ , Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ have the meaning defined in Embodiment A1.

Embodiment A3 is a further embodiment of Embodiment A1 or A2, wherein the compound or a pharmaceutically acceptable salt thereof is a compound of formula II:

or a pharmaceutically acceptable salt thereof, and wherein the variables R ¹ , R ² , R ³ , X ¹ , Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ have the meaning defined in Embodiment A1.

Embodiment A4 is a further embodiment of any of Embodiments A1 to A3, wherein the compound or a pharmaceutically acceptable salt thereof is a compound of formula III:

or a pharmaceutically acceptable salt thereof, and wherein the variables R ¹ , R ² , R ³ , Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ have the meaning defined in Embodiment A1.

Embodiment A5 is a further embodiment of any of Embodiments A1 to A4, wherein:

R ¹ represents H, halogen, C _1-4 alkyl, C _1-4 haloalkyl, C _3-6 cycloalkyl, 4-7 membered heterocycloalkyl, optionally substituted with 1-4 C _1-4 alkyl groups, or R ^1a ;

R ^1a is a 5- or 6-membered heteroaryl, optionally substituted with 1, 2, 3 or 4 independently selected R ^A groups, where each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _{1- 4} haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy, C _3-4 cycloalkyl or (C _3-4 cycloalkyl) -C _1-4 alkyl-, where each of C _1-4 alkyl, C _3-4 cycloalkyl and (C _3-4 cycloalkyl) -C _1-4 alkyl is optionally substituted with 1, 2, 3, 4 or 5 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _{1 -4} haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy; or two adjacent R ^A together with the two 5- or 6-membered heteroaryl ring atoms to which they are attached form a fused benzene ring or a fused 5- or 6-membered heteroaryl, each optionally substituted with 1, 2 or 3 substituents each of which is independently selected from halogen, -OH, -CN, alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy.

Embodiment Ab is a further embodiment of any of Embodiments A1 to A4, wherein R ¹ is H, halogen, or 4-7 membered heterocycloalkyl.

Embodiment A7 is a further embodiment of any of Embodiments A1 to A4, wherein R ¹ is H or halogen.

Embodiment A8 is a further embodiment of any of Embodiments A1 through A4, wherein R ¹ is H.

Embodiment A9 is a further embodiment of any of Embodiments A1 to A4, wherein R ¹ is halogen (eg, C1).

Embodiment A10 is a further embodiment of any of Embodiments A1 through A4, wherein R ¹ is a 4-7 membered heterocycloalkyl (e.g., tetrahydrofuranyl, tetrahydropyranyl, pyrrolidinyl, piperidinyl, piperazinyl, or morpholino), optionally substituted with 1-4 C _{1 -4} alkyl groups.

Embodiment A11 is a further embodiment of any of Embodiments A1 to A4, wherein R ¹ is R ^1a .

Embodiment A12 is a further embodiment of any of Embodiments A1 to A4, wherein:

R ¹ is R ^1a ; And

R ^1a is a 5-membered heteroaryl, optionally substituted with 1, 2, 3 or 4 independently selected R ^A groups, where each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy, C _3-4 cycloalkyl or (C _3-4 cycloalkyl)-C _1-4 alkyl-, where each of C _1-4 alkyl, C _3-4 cycloalkyl and (C _3-4 cycloalkyl) -C _1-4 alkyl- is optionally substituted with 1, 2, 3, 4 or 5 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl , C _1-4 alkoxy and C _1-4 haloalkoxy; or two adjacent R ^A together with the two ring atoms of the 5-membered heteroaryl to which they are attached form a fused 5- or 6-membered heteroaryl, each of which is optionally substituted with 1, 2 or 3 substituents, each of which is independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy.

Embodiment A13 is a further embodiment of Embodiment A11 or A12, wherein R ^1a is a 5-membered heteroaryl optionally substituted with 1, 2, 3 or 4 independently selected R ^A groups, wherein each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy, C _3-4 cycloalkyl or (C _3-4 cycloalkyl)-C _1-4 alkyl-, where each of C _1-4 alkyl, C _3-4 cycloalkyl and (C _3-4 cycloalkyl) -C _1-4 alkyl- optionally substituted with 1, 2, 3, 4 or 5 substituents, each independently selected from halogen, -OH , -CN, alkyl, haloalkyl, alkoxy and C _1-4 haloalkoxy.

Embodiment A14 is a further embodiment of Embodiment A11 or A12, wherein R ^1a is a 5-membered heteroaryl optionally substituted with 1, 2, 3, or 4 independently selected R ^A groups, wherein each R ^A is halogen, -OH, -CN, alkyl, haloalkyl, alkoxy, haloalkoxy or C _3-4 cycloalkyl.

Embodiment A15 is a further embodiment of any of Embodiments A12 A14, wherein each of the ring-forming atoms of the 5-membered heteroaryl R ^1a is a carbon or nitrogen atom.

Embodiment A16 is a further embodiment of Embodiment A11, wherein R ^1a is pyrazolyl, 1,2,4-triazolyl, 1,2,3-triazolyl, tetrazolyl, 1,2-thiazolyl, 1,3,4-thiadiazolyl , 1,2,4-thiadiazolyl, 1,3,4-oxadiazolyl, 1,2,4-oxadiazolyl, 1,3-thiazolyl, imidazolyl, pyrazolo[1,5-a]pyrimidinyl or [1,2,4] triazolo[1,5-a]pyridinyl-, each of which is optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy and C _3-4 cycloalkyl.

Embodiment A17 is a further embodiment of Embodiment A11, wherein R ^1a is 1H-pyrazol-4-yl, 1H-1,2,4-triazol-3-yl, 2H-1,2,3-triazol-4 -yl, 2H-tetrazol-5-yl, 1,2-thiazol-5-yl, 1,3,4-thiadiazol-2-yl, 1,2,4-thiadiazol-5-yl, 1,3,4 -oxadiazol-2-yl, 1, 2, 4-oxadiazol-3-yl, 1, 3-thiazol-2-yl, 1, 3-thiazol-4-yl, 1H-imidazol-4-yl, pyrazolo[1 ,5-a]pyrimidin-3-yl or [1,2,4]triazolo[1,5-a]pyridin-2-yl, each of which is optionally substituted with 1, 2 or 3 substituents, each of which is independently selected from halogen, -OH, -CN, alkyl, haloalkyl, alkoxy, haloalkoxy and C _3-4 cycloalkyl.

Embodiment A18 is a further embodiment of any of Embodiments A1 to A4, wherein:

R ¹ is R ^1a ; And

R ^1a is a 5-membered heteroaryl substituted with 2, 3 or 4 independently selected ^RAs , where each ^RA is halogen, -OH, -CN, C _1-4 alkyl, haloalkyl, C _1-4 alkoxy, C _{1 -4} haloalkoxy, C _3-4 cycloalkyl or (C _3-4 cycloalkyl)-C _1-4 alkyl-, where each of C _1-4 alkyl, C _3-4 cycloalkyl and (C _3-4 cycloalkyl)-C _{1 -4} alkyl- is optionally substituted with 1, 2, 3, 4 or 5 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy; or two adjacent R ^A together with the two ring atoms of the 5-membered heteroaryl to which they are attached form a fused 5- or 6-membered heteroaryl or a fused 5- or 6-membered heterocycloalkyl, each of which is optionally substituted with 1, 2 or 3 substituents , each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy.

Embodiment A19 is a further embodiment of Embodiment A18 wherein two R ^A are adjacent and they, together with the two 5-membered heteroaryl ring atoms to which they are attached, form a fused 5- or 6-membered heteroaryl that is optionally substituted with 1 , 2 or 3 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy; and wherein each of the remaining R ^A , if present, is independently halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy, C _3-4 cycloalkyl or (C _3-4 cycloalkyl)-C _1-4 alkyl-, wherein each of C _1-4 alkyl, C _3-4 cycloalkyl and (C _3-4 cycloalkyl)-C _1-4 alkyl- is optionally substituted with 1, 2, 3, 4 or 5 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy.

Embodiment A20 is a further embodiment of Embodiment A18 wherein two R ^A are adjacent and they, together with the two 5-membered heteroaryl ring atoms to which they are attached, form a fused 5- or 6-membered heterocycloalkyl that is optionally substituted with 1 , 2 or 3 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy; and wherein each of the remaining R ^A , if present, is independently halogen, -OH, -CN, C _1-4 alkyl, haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy, C _3-4 cycloalkyl or (C _3-4 cycloalkyl) -C _1-4 alkyl-, wherein each of C _1-4 alkyl, C _3-4 cycloalkyl and (C _3-4 cycloalkyl) -C _1-4 alkyl- is optionally substituted with 1, 2, 3, 4 or 5 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy.

Embodiment A21 is a further embodiment of any of Embodiments A1 to A4, where:

R ¹ is R ^1a ; And

R ^1a is a 6-membered heteroaryl, optionally substituted with 1, 2, 3 or 4 independently selected R ^A , where each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy, C _3-4 cycloalkyl or (C _3-4 cycloalkyl)-C _1-4 alkyl-, where each of C _1-4 alkyl, C _3-4 cycloalkyl and (C _{3 -4} cycloalkyl) -C _1-4 alkyl- is optionally substituted with 1, 2, 3, 4 or 5 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy; or two adjacent R ^A together with the two ring atoms of the 6-membered heteroaryl to which they are attached form a fused benzene ring or a fused 5- or 6-membered heteroaryl, each of which is optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy.

Embodiment A22 is a further embodiment of Embodiment A21, wherein R ^1a is a 6-membered heteroaryl, optionally substituted with 1, 2, 3, or 4 independently selected R ^A , wherein each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy, C _3-4 cycloalkyl or (C _3-4 cycloalkyl)-C _1-4 alkyl-, where each of C _{1 -4} alkyl, C _3-4 cycloalkyl and (C _3-4 cycloalkyl) -C _1-4 alkyl- is optionally substituted with 1, 2, 3, 4 or 5 substituents, each independently selected from halogen, -OH, -CN , C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy.

Embodiment A23 is a further embodiment of Embodiment A21, wherein R ^1a is a 6-membered heteroaryl, optionally substituted with 1, 2, 3, or 4 independently selected R ^A , and where each R ^A is halogen, -OH, -CN , C _1-4 alkyl, haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl.

Embodiment A24 is a further embodiment of any of Embodiments A21 through A23, wherein each of the ring-forming atoms of the 6-membered heteroaryl R ^1a is a carbon or nitrogen atom. In yet another embodiment, 1, 2 or 3 of the ring-forming atoms of the 6-membered heteroaryl R ^1a are nitrogen atoms (and the remaining of the ring-forming atoms are carbon atoms).

Embodiment A25 is a further embodiment of any of Embodiments A21 through A23, wherein R ^1a is pyridinyl, pyridazinyl, pyrazinyl, or pyrimidinyl, each optionally substituted with 1, 2, or 3 independently selected R ^A , wherein each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl.

Embodiment A26 is a further embodiment of any of Embodiments A21 to A23, wherein R ^1a is pyridin-2-yl, pyridin-3-yl, pyridazin-3-yl, pyridazin-4-yl, pyrazin-2-yl , pyrimidin-2-yl, pyrimidin-4-yl or pyrimidin-5-yl, each of which is optionally substituted with 1, 2 or 3 independently selected R ^A , where each R ^A is halogen, -OH, -CN, C _{1 -4} alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl.

Embodiment A27 is a further embodiment of any of Embodiments A21 through A23, wherein R ^1a is pyrimidinyl, optionally substituted with 1, 2, or 3 independently selected R ^A , wherein each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl.

Embodiment A28 is a further embodiment of any of Embodiments A21 through A23, wherein R ^1a is pyrimidin-2-yl, optionally substituted with 1 or 2 independently selected R ^A , wherein each R ^A is halogen, -OH, -CN , C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl.

Embodiment A29 is a further embodiment of any of Embodiments A21 through A23, wherein R ^1a is pyrimidin-2-yl.

Embodiment A30 is a further embodiment of any of Embodiments A1 through A4, wherein R ¹ is phenyl, wherein the phenyl is substituted with 3 or 4 independently selected ^RBs , where two adjacent ^RBs are together with the two ring-forming phenyl atoms to which they attached to form a fused 5- or 6-membered heteroaryl, each of which is optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _1-4 haloalkoxy; and where each of the remaining ^RB independently represents halogen, OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl;

Embodiment A31 is a further embodiment of Embodiment A30, wherein R ¹ is 1,2-benzoxazolyl (eg, 2-benzoxazol-6-yl) or 1,3-benzothiazolyl (eg, 1,3-benzothiazol-5- yl), each of which is optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy and C _{1- 4} haloalkoxy.

Embodiment A32 is a further embodiment of any of Embodiments A1 to A4, wherein R ¹ is phenyl, wherein phenyl is substituted with the group R ^B1 and is optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy and C _3-4 cycloalkyl.

Embodiment A33 is a further embodiment of Embodiment A32, wherein R ^B1 is 1,3,4-oxadiazolyl (e.g., 1,3,4-oxadiazol-2-yl), 1,2,4-oxadiazolyl (e.g., 1,2,4-oxadiazol-3-yl) or 1,3-oxazolyl (e.g. 1,3-oxazol-5-yl), each of which is optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy and C _3-4 cycloalkyl.

Embodiment A34 is a further embodiment of any of Embodiments A1 to A3 and A5 to A33, wherein X ¹ is CH ₂ .

Embodiment A35 is a further embodiment of any of Embodiments A1 to A3 and A5 to A33, wherein X ¹ is CH(CH ₃ ).

Embodiment A36 is a further embodiment of any of Embodiments A1 through A35, wherein R ² and R ³ are each independently H, F or C _1-4 alkyl.

Embodiment A37 is a further embodiment of any of Embodiments A1 through A33, wherein R ² and R ³ are each independently H, F or C _1-2 alkyl.

Embodiment A38 is a further embodiment of any of Embodiments A1 through A33, wherein R ² and R ³ are each independently H or C _1-4 alkyl.

Embodiment A39 is a further embodiment of any of Embodiments A1 through A33, wherein R ² and R ³ are each independently H or C _1-2 alkyl.

Embodiment A40 is a further embodiment of any of Embodiments A1 through A33, wherein ^R2 and ^R3 are each independently H or methyl.

Embodiment A41 is a further embodiment of any of Embodiments A1 through A35, wherein ^R2 is _C1-4 alkyl and ^R3 is H.

Embodiment A42 is a further embodiment of any of Embodiments A1 through A35, wherein R ² is C _1-2 alkyl and R ³ is H.

Embodiment A43 is a further embodiment of any of Embodiments A1 through A35 wherein ^R2 is methyl and ^R3 is H.

Embodiment A44 is a further embodiment of any of Embodiments A1 through A43, wherein Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ are each independently CR ⁴ .

Embodiment A45 is a further embodiment of any of Embodiments A1 through A43, wherein one of Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ is N and each of the others is independently CR ⁴ .

Embodiment A46 is a further embodiment of any of Embodiments A1 through A43, wherein Y ³ is N and Y ¹ , Y ² , Y ⁴ and Y ⁵ are each independently CR ⁴ .

Embodiment A47 is a further embodiment of any of Embodiments A1 through A43, wherein two of Y ¹ , Y ² , Y ³ , Y ⁴ , and Y ⁵ are N and each of the others is Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ independently represent CR ⁴ .

Embodiment A48 is a further embodiment of any of Embodiments A1 through A43, wherein Y ¹ is N, Y ³ is N, and Y ² , Y ⁴ and Y ⁵ are each independently CR ⁴ .

Embodiment A49 is a further embodiment of any of Embodiments A1 through A48, wherein each ^R4 is independently H, halogen, _C1-2 alkyl, _C1-2 haloalkyl, -N( _C1-4 alkyl) ₂ . C _1-2 alkoxy or C _1-2 haloalkoxy.

Embodiment A50 is a further embodiment of any of Embodiments A1 through A48, wherein each R ⁴ is independently H, F, Cl, -CH ₃ , C ₁ fluoroalkyl, -OCH ₃ or C ₁ fluoroalkoxy.

Embodiment A51 is a further embodiment of any of Embodiments A1 through A48, wherein each ^R4 is independently H, halogen, or C1-2 alkoxy.

Embodiment A52 is a further embodiment of any of Embodiments A1 through A48, wherein each ^R4 is independently H, F, Cl, or _-OCH3 .

Embodiment A53 is a further embodiment of any of Embodiments A1 through A48, wherein each R ⁴ is independently H, F, or -OCH ₃ .

Embodiment A54 is a further embodiment of any of Embodiments A1 to A3, wherein:

R ¹ is R ^1a ;

R ^1a is pyrazolyl, 1,2,4-triazolyl, 1,2,3-triazolyl, tetrazolyl, 1,2-thiazolyl, 1, 3, 4-thiadiazolyl, 1,2,4-thiadiazolyl, 1, 3, 4-oxadiazolyl, 1, 2, 4-oxadiazolyl, 1,3-thiazolyl, imidazolyl, pyrazolo[1,5-a]pyrimidinyl or [1,2,4]triazolo[1,5-a]pyridinyl-, each which is optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, alkoxy, C _1-4 haloalkoxy and C _3-4 cycloalkyl;

X ¹ represents CH ₂ or CH(CH ₃ );

R ² represents C _1-2 alkyl and R ³ represents H;

one of Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ is N and each of the others of Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ is independently CR ⁴ ; And

each R ⁴ independently represents H, F, Cl, -CH ₃ , C ₁ fluoroalkyl, -OCH ₃ or C ₁ fluoroalkoxy.

Embodiment A33 is a further embodiment of any of Embodiments A1 to A3, where:

R ¹ is R ^1a ;

R ^1a is 1,2,4-triazolyl, 1, 2,3-triazolyl or tetrazolyl (e.g. 2H-tetrazol-5-yl), each optionally substituted with 1, 2 or 3 substituents, each independently selected from halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy and C _3-4 cycloalkyl;

X ¹ represents CH ₂ ;

R ² represents C _1-2 alkyl and R ³ represents H;

Y ³ represents N and each of Y ¹ , Y ² , Y ⁴ and Y ⁵ independently represents CR ⁴ ; And

each R ⁴ independently represents H, F, Cl, -CH ₃ , C ₁ fluoroalkyl, -OCH ₃ or C ₁ fluoroalkoxy.

Embodiment A56 is a further embodiment of any of Embodiments A1 to A3, where:

R ¹ is R ^1a ;

R ^1a is tetrazolyl (e.g., 2H-tetrazol-5-yl), optionally substituted with 1, 2 or 3 independently selected R ^A , where each R ^A is halogen, -OH, -CN, alkyl, C _1-4 haloalkyl , alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl (eg R ^1a is 2H-tetrazol-5-yl substituted with C _1-4 alkyl such as methyl);

X ¹ represents CH ₂ ;

R ² represents methyl and R ³ represents H;

Y ³ represents N and each of Y ¹ , Y ² , Y ⁴ and Y ⁵ independently represents CR ⁴ ; And

each R ⁴ independently represents H, F, Cl or -OCH ₃ .

Embodiment A57 is a further embodiment of any of Embodiments A1 to A3, where:

R ¹ is R ^1a ;

R ^1a is pyrazolyl (e.g., 1H-pyrazol-4-yl), optionally substituted with 1, 2 or 3 independently selected R ^A , where each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl (eg R ^1a is 1H-pyrazol-4-yl substituted with C _1-4 alkyl such as methyl);

X ¹ represents CH ₂ ;

R ² represents methyl and R ³ represents H;

Y ³ represents N and each of Y ¹ , Y ² , Y ⁴ and Y ⁵ independently represents CR ⁴ ; And

each R ⁴ is independently H, F, Cl or -OCH ₃ (eg, each R ⁴ is independently H, F or -OCH ₃ ).

Embodiment A58 is a further embodiment of any of Embodiments A1 to A3, where:

R ¹ is R ^1a ;

R ^1a is pyridinyl, pyridazinyl, pyrazinyl or pyrimidinyl, each of which is optionally substituted with 1, 2 or 3 independently selected R ^A , where each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _{1- 4} haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl;

X ¹ represents CH ₂ or CH(CH ₃ );

R ² represents C _1-2 alkyl and R ³ represents H; one of Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ is N, and each of the others of Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ is independently CR ⁴ ; And

each R ⁴ is independently H, F, Cl, -CHF ₂ or

-basic3.

Embodiment A59 is a further embodiment of any of Embodiments A1 to A3, wherein:

R ¹ is R ^1a ;

R ^1a is pyridinyl, pyridazinyl, pyrazinyl or pyrimidinyl, each of which is optionally substituted with 1, 2 or 3 independently selected R ^A , where each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _{1- 4} haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl;

X ¹ represents CH ₂ ;

R ² represents C _1-2 alkyl and R ³ represents H;

Y ³ represents N and each of Y ¹ , Y ² , Y ⁴ and Y ⁵ independently represents CR ⁴ ; And

each R ⁴ independently represents H, F or -OCH ₃ .

Embodiment A60 is a further embodiment of any of Embodiments A1 to A3, wherein:

R ¹ is R ^1a ;

R ^1a is pyrimidinyl (eg, pyrimidin-2-yl), optionally substituted with 1, 2 or 3 independently selected R ^A , where each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _{1- 4} haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl (eg R ^1a is unsubstituted pyrimidin-2-yl);

X ¹ represents CH ₂ ;

R ² represents methyl and R ³ represents H;

Y ³ represents N and each of Y ¹ , Y ² , Y ⁴ and Y ⁵ independently represents CR ⁴ ; And

each R ⁴ is independently H, F, Cl or -OCH ₃ (eg, each R ⁴ is independently H, F or -OCH ₃ ).

Embodiment A61 is a further embodiment of any of Embodiments A1 to A3, wherein:

R ¹ is R ^1a ;

R ^1a is [1, 2, 4]triazolo[1,5-a]pyridin-2-yl, optionally substituted with 1, 2 or 3 independently selected ^RAs , where each ^RA is halogen, -OH, -CN , alkyl, C _1-4 haloalkyl, alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl (for example, R ^1a is unsubstituted [1,2,4]triazolo[1,5-a]pyridin-2-yl );

X ¹ represents CH ₂ ;

R ² represents methyl and R ³ represents H;

Y ³ represents N and each of Y ¹ , Y ² , Y ⁴ and Y ⁵ independently represents CR ⁴ ; And

each R ⁴ is independently H, F, Cl or -OCH ₃ (eg, each R ⁴ is independently H, F or -OCH ₃ ).

Embodiment A62 is a further embodiment of any of Embodiments A1 to A3, wherein:

R ¹ is R ^1a ;

R ^1a is pyridinyl, pyridazinyl, pyrazinyl or pyrimidinyl, each of which is optionally substituted with 1, 2 or 3 independently selected R ^A , wherein each R ^A is halogen, -OH, -CN, C _1-4 alkyl, C _{1- 4} haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl;

X ¹ represents CH ₂ or CH(CH ₃ );

R ² represents C _1-2 alkyl and R ³ represents H;

Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ are each independently CR ⁴ ; And

each R ⁴ is independently H, F, Cl, -CH ₃ , CF ₃ , -CHF ₂ or -OCH ₃ .

Embodiment A63 is a further embodiment of any of Embodiments A1 to A3, where:

R ¹ represents H;

X ¹ represents CH ₂ or CH(CH ₃ );

R ² and R ³ are each independently H or C _1-2 alkyl (eg, R ² and R ³ are each H);

Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ are each independently CR ⁴ ; And

each R ⁴ is independently H, F, Cl, -CH ₃ , CF ₃ , -CHF ₂ or -OCH ₃ (e.g., each R ⁴ is independently H or F, e.g., one of the R ⁴ is F and each of the others, R ⁴ is H).

Embodiment A64 (an additional embodiment of Embodiment A1) provides a compound selected from Examples 1-201 of the EXAMPLES section, or a pharmaceutically acceptable salt thereof (or a parent compound thereof when the exemplary compound is, for example, a salt) described herein .

Embodiment A65 (an additional embodiment of Embodiment A1) provides a connection selected from

2-(5-chloro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1 ,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

2-(b-methoxy-2-methylpyrimidin-4-yl)-1-[7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1 ,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

2-[6-(difluoromethoxy)pyridin-3-yl]-1-[7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2, 3'-pyrrolidin]-1'-yl]propan-1-one;

1-[7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]-2-[ 4-(trifluoromethyl)phenyl]propan-1-one;

1-(4,7-dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethane-1- she;

2-(5-fluoro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1 ,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

2-(5-fluoro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2 ,3'-pyrrolidin]-1'-yl]propan-1-one;

2-(5-chloro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2 ,3'-pyrrolidin]-1'-yl]propan-1-one;

2-(5-fluoro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H-spiro[1 ,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one; And

2-(5-fluoro-2-methoxypyridin-4-yl)-1-{7-methyl-6-[(4,6- ² H ₂ )pyrimidin-2-yl]-3,4-dihydro-1H- spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl}propan-1-one,

or a pharmaceutically acceptable salt thereof.

Embodiment A66 (an additional embodiment of Embodiment 1) provides a connection selected from

(2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

2-(6-methoxy-2-methylpyrimidin-4-yl)-1-[{2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

2-[b-(difluoromethoxy)pyridin-3-yl]-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8- naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl] -2-[4-(trifluoromethyl)phenyl]propan-1-one;

1-(4,7-dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethane-1- she;

(2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4 -dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

(2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

(2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

(2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one; And

(2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-{(2S)-7-methyl-6-[(4,6- ² H ₂ )pyrimidin-2-yl]- 3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl}propan-1-one,

or a pharmaceutically acceptable salt thereof.

Embodiment A67 (an additional embodiment of Embodiment A1) provides a connection selected from:

(2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1;

2-(6-methoxy-2-methylpyrimidin-4-yl)-1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1;

2-[6-(difluoromethoxy)pyridin-3-yl]-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8- naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-2;

1-[(25)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl] -2-[4-(trifluoromethyl)phenyl]propan-1-one, DIAST-1;

1-(4,7-dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethane-1- she, DIAST-1;

(2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[{2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4 -dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

(2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

(2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one;

(2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1; And

(2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-{(25)-7-methyl-6-[(4, 6-2H ₂ )pyrimidin-2-yl]-3 ,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl}propan-1-one,

or a pharmaceutically acceptable salt thereof.

Embodiment A68 (an additional embodiment of Embodiment A1) provides a compound that is (2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6- (pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one or a pharmaceutically acceptable salt thereof.

Embodiment A69 (an additional embodiment of Embodiment A1) provides a compound that is (2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6- (pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one.

Embodiment A70 (a further embodiment of Embodiment A69) provides the crystalline form of (2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin- 2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one. In yet another embodiment of Embodiment A70, the crystalline form exhibits a powder x-ray diffraction pattern including at least one characteristic peak, expressed in degrees 2θ, selected from 8.7±0.2°; 11.1±0.2°; and 13.3±0.2°.

In yet another embodiment of Embodiment A70, the crystalline form is Form I, described herein in Example 14. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least one characteristic peak, expressed in degrees 2θ, at 8 .7±0.2°. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least one characteristic peak, expressed in degrees 2θ, at 11.1±0.2°. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least one characteristic peak, expressed in degrees 2θ, at 13.3±0.2°. In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; 11.1±0.2°; and 13.3±0.2°. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including two characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; and 11.1±0.2. In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least three characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; 11.1±0.2°; and 13.3±0.2°.

In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; 11.1±0.2°; and 26.0±0.2. In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; and 26.0±0.2°. In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ selected from 11.1±0.2°; and 26.0±0.2°. In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least three characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; 11.1±0.2°; and 26.0±0.2°.

In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ, which are presented in Table X1. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least three characteristic peaks expressed in degrees 2θ, which are presented in Table X1. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least four (eg, 4, 5, 6, 7, 8, 9, or 10) characteristic peaks expressed in degrees 2θ, which are presented in Table X1.

In some embodiments, Form I exhibits a powder x-ray diffraction pattern substantially as shown in FIG. 1.

Each embodiment, Example, or pharmaceutically acceptable salt thereof may be claimed individually or grouped together in any combination with any number of each individual embodiment described herein.

The spirocyclic compound of formula I (also including a compound of formula la, II or III) of the invention can be used in any of the pharmaceutical compositions, uses and methods of the invention described herein.

The compound of formula I or a pharmaceutically acceptable salt thereof of the present invention is an MC4R antagonist. Thus, the present invention also provides a method of antagonizing MC4R (either in vitro or in vivo), comprising contacting (including incubation) MC4R with a compound of Formula I or a pharmaceutically acceptable salt thereof (e.g., a compound selected from Embodiments A1 to A70 or Examples 1-201 presented in this application) described in this application.

The amount of a compound of Formula I or a pharmaceutically acceptable salt thereof used in any of the methods (or uses) of the present invention is effective to antagonize MC4R.

Another embodiment of the present invention involves the use of a compound of Formula I or a pharmaceutically acceptable salt of the compound (such as a compound selected from Embodiments A1 to A70 or Examples 1-201 provided herein) as a drug, particularly when the drug is intended for use in the treatment of an MC4R-related condition, disease or disorder, comprising administering to a mammal, such as a human, in need of such treatment a therapeutically effective amount.

Another embodiment of the present invention includes the use of a compound of Formula I or a pharmaceutically acceptable salt of the compound (such as a compound selected from Embodiments A1 to A70 or Examples 1-201 provided herein) for the preparation of a medicament for the treatment of an MC4R-related condition. a disease or disorder which involves administering to a mammal, such as a human, in need of such treatment a therapeutically effective amount.

Another embodiment of the present invention involves the use of a compound of Formula I or a pharmaceutically acceptable salt of the compound (such as a compound selected from Embodiments A1 to A70 or Examples 1-201 provided herein) as a drug, particularly when the drug is intended for use in the treatment of a condition, disease or disorder selected from cachexia [including, for example, cachexia associated with a chronic disease such as cachexia associated with cancer, cachexia associated with acquired immunodeficiency syndrome (AIDS), cachexia associated with cardiac failure, eg cachexia associated with congestive heart failure (CHF), cachexia associated with chronic kidney disease (CKD); cachexia associated with the treatment of a chronic disease, such as cachexia associated with the treatment of cancer or cachexia associated with the treatment of heart failure (eg, CHF)]; anorexia or anorexia nervosa (eg, anorexia in the elderly, anorexia associated with chemotherapy and/or radiation therapy); nausea; vomiting; weight loss (eg, unintentional weight loss); developmental delays; sarcopenia; muscle atrophy; muscle weakness; weakness; osteoporosis; bone diseases (eg, bone loss); pain; neuropathic pain; anxiety (such as post-traumatic stress disorder, or PTSD); depression; hypertension; eating disorders; obesity (eg, sarcopenia due to chronic obesity); sexual dysfunction; and an inflammatory disease (eg, an inflammatory disease associated with anorexia, or cachexia, or sarcopenia, or muscle atrophy), which includes administering to a mammal, such as a human, in need of such treatment, a therapeutically effective amount of the compound or a pharmaceutically acceptable salt thereof.

Another embodiment of the present invention involves the use of a compound of Formula I or a pharmaceutically acceptable salt of a compound (such as a compound selected from Embodiments A1 to A70 or Examples 1 to 201 provided herein) for the preparation of a medicament for treating a condition, disease, or disorder , selected from cachexia [including, for example, cachexia associated with chronic disease, such as cachexia associated with cancer, cachexia associated with acquired immunodeficiency syndrome (AIDS), cachexia associated with heart failure, such as cachexia associated with congestive heart failure (CHF), cachexia associated with chronic kidney disease (CKD); cachexia associated with the treatment of a chronic disease, such as cachexia associated with the treatment of cancer or cachexia associated with the treatment of heart failure (eg, CHF)]; anorexia or anorexia nervosa (eg, anorexia in the elderly, anorexia associated with chemotherapy and/or radiation therapy); nausea; vomiting; weight loss (eg, unintentional weight loss); developmental delays; sarcopenia; muscle atrophy; muscle weakness; weakness; osteoporosis; bone diseases (eg, bone loss); pain; neuropathic pain; anxiety (such as post-traumatic stress disorder, or PTSD); depression; hypertension; eating disorders; obesity (eg, sarcopenia due to chronic obesity); sexual dysfunction; and an inflammatory disease (for example, an inflammatory disease associated with anorexia, or cachexia, or sarcopenia, or muscle atrophy), which includes administering to a mammal, such as a human, in need of such treatment, a therapeutically effective amount of a compound of formula I or a pharmaceutically acceptable salt of such a compound .

The compounds of the present invention may contain asymmetric or chiral centers and therefore exist in various stereoisomeric forms. Unless otherwise indicated, all stereoisomeric forms of the compounds of the present invention, as well as mixtures thereof, including racemic mixtures, are intended to form part of the present invention. Moreover, the present invention covers all geometric and positional isomers. For example, if a compound of the present invention includes a double bond or a fused ring, both cis and trans forms, as well as mixtures, are within the scope of the invention.

The chiral compounds of the invention (and their chiral precursors) can be prepared in enantiomerically enriched form using chromatography, typically high performance liquid chromatography (HPLC) or supercritical fluid chromatography (SFC), on a resin with an asymmetric stationary phase and with a mobile phase consisting of a hydrocarbon, typically heptane or hexane, containing from 0 to 50% isopropanol, typically from 2 to 20%, and from 0 to 5% alkylamine, typically 0.1% diethylamine (DEA) or isopropylamine. The concentration of the eluent produces a rich mixture. When using SFC, the mobile phase may consist of a supercritical fluid, typically carbon dioxide, containing 2-50% alcohol such as methanol, ethanol or isopropanol.

Diastereomeric mixtures can be separated into their individual diastereoisomers based on their physicochemical differences by methods well known to those skilled in the art, such as chromatography and/or fractional crystallization. Enantiomers can be separated by converting an enantiomeric mixture to a diastereomeric mixture by reacting with a suitable optically active compound (e.g., a chiral auxiliary such as a chiral alcohol or Mosher acid chloride), separating the diastereoisomers, and converting (e.g., by hydrolysis) the individual diastereoisomers to the corresponding pure enantiomers . Enantiomers can also be separated on a chiral HPLC column. Alternatively, certain stereoisomers can be synthesized using an optically active starting material, by asymmetric synthesis using optically active reagents, substrates, catalysts or solvents, or by converting one stereoisomer to another by asymmetric transformation.

In some embodiments, the compounds of the invention may contain asymmetric carbon atoms. Carbon-carbon bonds of compounds of formula I can be shown in this application using a solid line ( ), wavy line , solid wedge or hatched wedge . Using a solid line to represent bonds to asymmetric carbon atoms means that all possible stereoisomers (eg, specific enantiomers, racemic mixtures, etc.) at that carbon atom are included. The use of a solid or hatched wedge to represent bonds with asymmetric carbon atoms means that only the stereoisomer shown is intended to be included. The use of a wavy line to represent bonds with asymmetric carbon atoms means that the stereochemistry is unknown (unless otherwise noted). There may be cases where the compounds of the invention may contain more than one asymmetric carbon atom. For such compounds, the use of a solid line to represent bonds with asymmetric carbon atoms means that all possible stereoisomers are intended to be included. For example, unless otherwise indicated, it is intended that the compounds of the invention may exist as enantiomers and diastereomers or as racemates and mixtures thereof. The use of a solid line to represent bonds to one or more asymmetric carbon atoms in a compound of the invention and the use of a solid or hatched wedge to represent bonds to other asymmetric carbon atoms in the same compound means that a mixture of diastereomers is present.

When the compounds of the present invention have two or more stereogenic centers and the name indicates absolute or relative stereochemistry, the designations R and S refer respectively to each stereogenic center in ascending numerical order (1, 2, 3, etc.) in accordance with generally accepted IUPAC numbering systems for each molecule. When compounds of the present invention have one or more stereogenic centers and the stereochemistry is not indicated in either the name or structure, the name or structure is intended to cover all forms of the compound, including the racemic form.

The compounds of the present invention may contain olefin-like double bonds. When such bonds are present, the compounds of the invention exist in cis and trans configurations and in mixtures thereof. The term "cis" refers to the orientation of the two substituents relative to each other and the plane of the ring (either both "up" or both "down"). Likewise, the term "trans" refers to the orientation of two substituents relative to each other and the plane of the ring (the substituents are on opposite sides of the ring).

It is also possible that the intermediates and compounds of the present invention may exist in different tautomeric forms, and all such forms are included within the scope of the invention. The term "tautomer" or "tautomeric form" refers to structural isomers with different energies that are interconvertible across a low energy barrier. For example, protic tautomers (also known as prototropic tautomers) involve interconversions via proton migration, such as keto-enol and imine-enamine isomerization.

Valence tautomers involve interconversions due to the reorganization of some of the bonding electrons.

Included within the scope of the claimed compounds of the present invention are all stereoisomers, geometric isomers and tautomeric forms of the compounds of formula I, including compounds exhibiting more than one type of isomerism, and mixtures of one or more of them. Also included are acid or base addition salts in which the counterion is optically active, such as D-lactate or L-lysine, or racemic, such as DL-tartrate or DL-arginine.

The present invention includes all pharmaceutically acceptable isotopically labeled compounds of formula I in which one or more atoms are replaced by atoms having the same atomic number but an atomic mass or mass number different from the atomic mass or mass number typically found in nature.

Examples of isotopes suitable for inclusion in the compounds of the invention include isotopes of hydrogen such as ² H and ³ H, carbon such as ¹¹ C, ¹³ C and ¹⁴ C, chlorine such as ³⁶ Cl, fluorine such as ¹⁸ F, iodine such as ¹²³ I, ¹²⁴ I and ¹²⁵ I, nitrogen such as ¹³ N and ¹⁵ N, oxygen such as ¹⁵ O, ¹⁷ O and ¹⁸ O, phosphorus such as ³² P and sulfur such as ³⁵ S .

Certain isotopically labeled compounds of formula I, for example those containing a radioactive isotope, are useful in drug and/or substrate tissue distribution studies. Radioactive isotopes tritium, i.e. ³ H, and carbon-14, i.e. ¹⁴ C are particularly useful for this purpose due to their ease of administration and convenient detection methods.

Substitution with heavier isotopes such as deuterium, i.e. ^2H may provide certain therapeutic benefits due to greater metabolic stability, such as increased in vivo half-life or reduced dosage requirements, and therefore may be preferred in some circumstances.

Substitution with positron-emitting isotopes such as ¹¹ C, ¹⁸ F, ¹⁵ O and ¹³ N can be useful in positron emission tomography (PET) studies to study the extent of receptor occupancy by a substrate.

Isotopically labeled compounds of Formula I can generally be prepared by conventional methods known to those skilled in the art, or by methods similar to those described in the accompanying Examples and Preparations, using appropriate isotopically labeled reagents in place of the previously used unlabeled reagent.

The compounds of the present invention can be isolated and used as such or, when possible, in the form of a pharmaceutically acceptable salt thereof. The term "salts" refers to inorganic and organic salts of the compound of the present invention. These salts can be prepared in situ during the final isolation and purification of the compound or by separately treating the compound with a suitable organic or inorganic acid and isolating the salt thus formed.

Salts encompassed by the term "pharmaceutically acceptable salts" refer to the compounds of the present invention, which are typically prepared by reacting the free base with a suitable organic or inorganic acid to produce a salt of the compound of the present invention suitable for administration to a patient. Suitable acid addition salts are formed from acids that form non-toxic salts. Examples of salts include acetate, adipate, aspartate, benzoate, besylate, bicarbonate/carbonate, bisulfate/sulfate, borate, camsylate, citrate, cyclamate, edisilate, esylate, formate, fumarate, gluceptate, gluconate, glucuronate, hexafluorophosphate, gibensate, hydrochloride/chloride , hydrobromide/bromide, hydroiodide/iodide, isethionate, lactate, malate, maleate, malonate, mesylate, methyl sulfate, naphthylate, 2-napsylate, nicotinate, nitrate, orotate, oxalate, palmitate, pamoate, phosphate/hydrogen phosphate/dihydrogen phosphate, pyroglutamate, saccharate , stearate, succinate, tannate, tartrate, tosylate, trifluoroacetate and xinofoate. See, for example, Berge, et al. J. Pharm. Sci. 66, 1-19 (1977); Handbook of Pharmaceutical Salts: Properties, Selection and Use by Stahl and Wermuth (Wiley-VCH, 2002).

The compounds of formula I and their pharmaceutically acceptable salts may exist in unsolvated and solvated forms. The term "solvate" is used herein to describe a molecular complex comprising a compound of formula I or a pharmaceutically acceptable salt thereof and one or more molecules of a pharmaceutically acceptable solvent, for example ethanol. The term "hydrate" is used when said solvent is water.

The currently accepted classification system for organic hydrates is one that defines isolated site hydrates, channel hydrates, or metal ion coordinated hydrates - see Polymorphism in Pharmaceutical Solids by K.R. Morris (Ed. H. G. Brittain, Marcel Dekker, 1995). Isolated site hydrates are hydrates in which the water molecules are isolated from direct contact with each other by intermediate organic molecules. In channel hydrates, water molecules are found in lattice channels, where they are close to other water molecules. In metal-ion-coordinated hydrates, water molecules are bound to the metal ions.

When solvent or water is tightly bound, the complex can have a well-defined stoichiometry that is independent of humidity. However, when the solvent or water is weakly bound, as in channel solvates and hygroscopic compounds, the water/solvent content may depend on humidity and drying conditions. In such cases, non-stoichiometry will be the norm.

Also included within the scope of the invention are multicomponent complexes (other than salts and solvates) in which the drug and at least one other component are present in stoichiometric or non-stoichiometric amounts. Complexes of this type include clathrates (drug-host inclusion complexes) and cocrystals. The latter are usually defined as crystalline complexes of neutral molecular constituents that are associated with each other through non-covalent interactions, but can also represent a complex of a neutral molecule with a salt. Cocrystals can be prepared by melt crystallization, recrystallization from solvents, or by physically grinding the components together - see O. Almarsson and M.J. Zaworotko, Chem. Commun.f 17, 1889-1896 (2004). For a general overview of multicomponent complexes, see Haleblian, J. Pharm. Sci., 64(8), 1269-1288 (1975).

The compounds of the invention include compounds of formula I or pharmaceutically acceptable salts thereof as defined above, polymorphs and isomers thereof (including optical, geometric and tautomeric isomers) as defined below, and isotopically labeled compounds of formula I or pharmaceutically acceptable salts thereof.

The compounds of the present invention can be administered as prodrugs. Thus, certain derivatives of compounds of formula I or pharmaceutically acceptable salts thereof, which themselves may have little or no pharmacological activity, may, when administered orally or applied to the body surface, be converted into compounds of formula I or pharmaceutically acceptable salts thereof having the desired activity. for example, as a result of hydrolytic cleavage. Such derivatives are called "prodrugs". [Additional information on the use of prodrugs can be found in Prodrugs as Novel Delivery Systems, Vol. 14, ACS Symposium Series (T. Higuchi and W. Stella) and “Bioreversible Carriers in Drug Design”, Pergamon Press, 1987 (ed. E.B. Roche, American Pharmaceutical Association).]

Prodrugs can be prepared, for example, by replacing the corresponding functional groups present in the compounds of formula I or their pharmaceutically acceptable salts with certain groups known to those skilled in the art as lpro groups, as described, for example, in "Design of Prodrugs" by H. Bundgaard (Elsevier, 1985).

Some examples of such prodrugs include:

(i) when the compound of formula I or a pharmaceutically acceptable salt thereof contains an alcohol functional group (-OH) - ester of such a compound, for example, replacement of hydrogen with (C ₁ -C ₆ )alkanoyloxymethyl; or phosphate ester (-O-PO ₃ H ₂ ) or sulfate ester (-O-SO ₃ H) or pharmaceutically acceptable salts thereof; And

(ii) the amide or carbamate of the amino functional group present in formula (I) or (II), wherein the hydrogen of the amino NH group is replaced by (C ₁ -C ₁₀ )alkanoyl or (C ₁ -C ₁₀ )alkoxycarbonyl, respectively.

Also included within the scope of the invention are the active metabolites of the compounds of formula I (including prodrugs) or their pharmaceutically acceptable salts, i.e. compounds formed in vivo upon administration of a drug, often as a result of oxidation or dealkylation. Some examples of metabolites in accordance with the invention include:

(i) when the compound of formula I or a pharmaceutically acceptable salt thereof contains a methyl group, the hydroxymethyl derivative of such compound (-CH ₃ → -CH ₂ OH), and

(ii) when the compound of formula I or a pharmaceutically acceptable salt thereof contains an alkoxy group, a hydroxy derivative of such compound (-OR → -OH).

Some compounds of the present invention may exist in more than one crystalline form (commonly referred to as "polymorphs"). Polymorphs can be obtained by crystallization under different conditions, for example, using different solvents or different mixtures of solvents for recrystallization; crystallization at different temperatures; and/or different cooling modes, from very fast to very slow cooling during the crystallization process. Polymorphs can also be prepared by heating or melting a compound of the present invention followed by gradual or rapid cooling. The presence of polymorphs can be determined by solid probe NMR spectroscopy, IR spectroscopy, differential scanning calorimetry, powder X-ray diffraction, or other similar methods.

In general, the compounds of the present invention can be prepared by methods that include those known in the art of chemistry, especially in light of the description contained herein. Certain methods for preparing the compounds of the present invention are provided as additional features of the invention and are illustrated by the following reaction schemes. Other methods can be described in the experimental section. Specific schemes for the synthesis of compounds of formula I or their pharmaceutically acceptable salts are given below. It should be noted that tetrazoles are typically a high-energy functional group, and care should be taken when synthesizing and handling tetrazole-containing molecules.

For the synthesis of the compounds of the present invention, synthetic routes can be used that include methods similar to those well known in the field of chemistry, especially in light of the description contained herein. The starting materials are generally available from commercial sources, such as MilliporeSigma (Milwaukee, WI), or can be easily prepared by methods well known to those skilled in the art [for example, can be prepared by methods generally described in Louis F. Fieser and Mary Fieser, Reagents for Organic Synthesis, v. 1-19, Wiley, New York (1967-1999 ed.), or Beilsteins Handbuch der Organischen Chemie, 4, Aufl. ed. Springer-Verlag, Berlin, including appendices (also available in the Beilstein online database)]. Many of the compounds used in this application are related to or derived from compounds of great scientific interest and commercial need, and accordingly, many such compounds are commercially available or reported in the literature, or are easily prepared from other publicly available compounds by the methods described in literature.

It should be noted that in the preparation of compounds of Formula I or salts thereof, some preparation methods described herein may require protection of a remote functional group (eg, primary amine, secondary amine, carboxyl in Formula I precursors). The need for such protection will vary depending on the nature of the remote functional group and the conditions of the production methods. The need for such protection can be easily determined by one skilled in the art. The use of such protection/deprotection methods is also within the competence of those skilled in the art. For a general description of protecting groups and their uses, see T.W. Greene, Protective Groups in Organic Synthesis, 5th Edition, John Wiley & Sons, New York, 2014. For example, some compounds contain primary amine or carboxylic acid functional groups that can interfere with reactions at other sites in the molecule if left unprotected. Accordingly, such functional groups can be protected by an appropriate protecting group, which can be removed in a subsequent step. Suitable protecting groups for protecting amines and carboxylic acids include those protecting groups commonly used in peptide synthesis (such as N-tert-butoxycarbonyl (Boc), benzyloxycarbonyl (Cbz) and 9-fluorenylmethoxycarbonyl (Fmoc) for amines and lower alkyl or benzyl esters for carboxylic acids), which are generally not chemically reactive under the reaction conditions described and can usually be removed without chemically altering other functional groups in the compounds of formula I.

The reactions can be monitored by any suitable method known in the art. For example, product formation can be monitored by spectroscopic techniques such as nuclear magnetic resonance spectroscopy (eg, CN or 13C), infrared spectroscopy, spectrophotometry (eg, UV-visible), mass spectrometry, or

chromatographic methods such as high performance liquid chromatography (HPLC) or thin layer chromatography (TLC).

The compounds of formula I, their salts and intermediates can be prepared in accordance with the following reaction schemes and accompanying discussion. The reaction schemes described below are intended to provide a general description of the methodology used in the preparation of the compounds of the present invention.

Some of the compounds of the present invention contain a single chiral center with a stereochemical designation (R or S), and others will contain two separate chiral centers with a stereochemical designation (R or S). It will be apparent to those skilled in the art that most synthetic transformations can be accomplished in this manner, regardless of whether the substances are enantioenriched or racemic. In addition, separation into the desired optically active species can occur at any desired point in the sequence using well known methods such as those described herein and in the chemistry literature.

Unless otherwise indicated, R ¹ , R ² , R ³ , X ¹ , Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ and structural Formula I (including, for example, Ia, II) in the reaction schemes and discussion, which are set forth below have the same meaning as defined herein or as described herein. In general, the compounds of the present invention can be prepared by methods that include methods similar to those known in the field of chemistry, in particular in light of the description contained in this application. Certain methods for preparing the compounds of the present invention and their intermediates are provided as additional features of the invention and are illustrated by the following reaction schemes. Other methods can be described in the experimental section. The diagrams and examples presented in this application (including the corresponding description) are presented for illustration purposes only and are not intended to limit the scope of the present invention.

In the Reaction Schemes, which are presented below, the variables X ^c , X ² , X ³ , X ⁴ , X ⁵ , X ⁶ , X ⁷ , X ⁸ , X ⁹ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R 13 , ^{R 14 ,} LG ¹ , LG ² , LG ³ , LG ⁴ , PG ^{1 , PG 2 ,} PG ³ , PG 4 , PG ⁵ , PG ⁶ , PG ^{7 and} PG ⁸ have the same meaning as defined herein or as described herein in the claims for Formula I unless otherwise stated. For each variable, its meaning remains the same as described above unless otherwise noted later.

Scheme 1 relates to the synthesis of compounds of formula I, Ia and II. Acids of formula 1-1 can be reacted with amines of formula 1-2 (or salts thereof) using standard amidation conditions using coupling reagents such as 1,1'-carbonyldiimidazole, 2,4,6-tripropyl-1, 3,5,2,4,6-trioxatriphosphinan 2,4,6-trioxide (T3P), O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) or others to give compounds of formula I. Alternatively, acids of formula 1-1 can be reacted with amines of formula 1-3 in a similar manner to give compounds of formula Ia. Acids of formula 1-1 can be purchased commercially, synthesized as described in Org. Process Res. Dev. 1997, 1, 72, or synthesized as described herein. Amines of formula 1-2 can be synthesized as described herein. Compounds of formula I that contain mixtures of enantiomers or diastereomers can be separated using supercritical fluid chromatography or reverse phase chiral column chromatography when it is necessary to separate them into individual diastereomers or enantiomers as required to obtain compounds of formula Ia or II.

Scheme 2 describes an alternative synthesis of compounds of the formula

II, when one enantiomer of acids of formula 2-1 (a subtype of acids of formula 1-1) is used. Some acids of formula 2-1 can be racemized or epimerized under some general amidation conditions as described in Scheme 1. Instead, by using lower temperatures, using solvents that promote dissolution of the reactants, using additives such as imidazolium salts or pyridinium, or other methods described in Org. Process Res. Dev. 2016, 20, 140; Org. Lett. 2012, 14, 1970; or Org. Process Res. Dev. 2009, 13, 106, or using the free base form of the amines of formula 1-3, a high enantiomeric excess can be maintained during the reaction. Alternatively, if general conditions are used or if epimerization or racemization occurs, the mixture of diastereomers formed can be separated using supercritical fluid or reverse phase chromatography with a chiral column, or they can be separated as a diastereomeric salt with the appropriate chiral acid under conventional separation conditions to give compounds of formula II.

Scheme 3 describes a method for synthesizing the acid of Formula 2-1 selectively as a single enantiomer. The acids of formula 3-1 can be purchased commercially or synthesized using methods described in the literature or in this application, and they can be reacted with a well known chiral auxiliary agent (Xe), for example an agent like the Evans agent (optically pure oxazolidinones), Myers' agent (pseudoephedrine derivative) or others described in the literature to obtain intermediate compounds of formula 3-2. Treatment of compounds of formula 3-2 with a strong base such as lithium diisopropylamide, lithium bis(trimethylsilyl)amide,

sodium bis(trimethylsilyl)amide, potassium bis(trimethylsilyl)amide or the like, and an alkyl halide (when R ² and/or R ³ is an alkyl group) or other electrophiles such as N-fluorobenzenesulfonimide (when R ² and/or or R ³ is fluorine) can give compounds of formula 3-3 with high diastereomeric excess. The conditions for hydrolysis of the X ^c group in compounds of formula 3-3 depend on the individual properties, but often reagents (inorganic bases) such as pure or aqueous potassium hydroxide, sodium hydroxide, lithium hydroxide, with or without hydrogen peroxide, and protic solvents such as methanol, ethanol or others, or aprotic solvents such as tetrahydrofuran, among others.

Scheme 4 describes methods that can be used to synthesize acids of formula 4-9 (subtype of compounds of formula 1-1), 4-7 (subtype of compounds of formula 2-1) or 4-8 (subtype of compounds of formula 2-1). Aryl or heteroaryl compounds of formula 4-1 [where X ² represents a halide (e.g., F, Cl, Br or I) or a leaving group such as -OTf] can be reacted with disprotected malonates of formula 4-2 (where PG ¹ can be methyl, ethyl, tert-butyl, benzyl, p-methoxybenzyl or the like, and PG ² may be an orthogonally leaving protecting group which is selected from the above or may be the same protecting group) using SNAr conditions or by cross-coupling using a palladium catalyst such as palladium(II) acetate or tris(dibenzylideneacetone)dipalladium(0) [Pd ₂ (dba) ₃ ] or others, with a range of available phosphine ligands, or a copper catalyst such as copper(I) iodide, or an acidic ligand such as 2-picolinic acid, as described in Org. Lett. 2007, 9, 3469, yielding intermediates of formula 4-3. The compounds of formula 4-3 can be treated with a suitable base such as sodium hydride, lithium diisopropylamide, lithium bis(trimethylsilyl)amide, sodium bis(trimethylsilyl)amide, potassium bis(trimethylsilyl)amide, potassium carbonate, cesium carbonate or the like, and then alkylated with alkylating reagents such as methyl iodide, ethyl iodide or others, fluorinating agents such as N-fluorobenzenesulfonimide, or other electrophiles to give compounds of formula 4-4. Alternatively, compounds of Formula 4-1 can be reacted with compounds of Formula 4-6 to directly form compounds of Formula 4-4 (under the same conditions as converting compounds of Formula 4-1 to compounds of Formula 4-3). Removal of the protecting groups of compounds of formula 4-4 can be accomplished using standard methods (alkaline or acid hydrolysis); or, when PG ¹ or PG ² is benzyl, by using palladium catalysts with hydrogen or reducing agent sources such as formate, trialkylsilanes or others to produce intermediates of formula 4-5. Alternatively, the compounds of formula 4-4 can directly form the acids of formula 4-9 under the same conditions (as those for preparing the compounds of formula 4-5), or where elevated temperatures may be required. Di-acids of formula 4-5 can also be mono-decarboxylated to give racemic acids of formula 4-9 using a base, acid, copper(I) oxide, heat or other suitable conditions. Acids of formula 4-9, which contain mixtures of enantiomers, can be separated using supercritical fluid or reverse phase chromatography with a chiral column, or they can be separated and isolated as a diastereomeric salt with the corresponding chiral acid under classical separation conditions, such as those described in Org. Process Res. Dev. 2011, 15, 53, or one enantiomer can be selectively converted to an ester using biocatalysis as described in Adv. Synth. Catal., 2009, 351, 2333 (see also J. Org. Chem. 2003, 68, 7234), and resolve to give acids of formula 4-7 or 4-8 with high enantiomeric excess. Di-acids of formula 4-5 can also be mono-decarboxylated using biocatalysis, such as arylmalonate decarboxylase (AMDase) enzymes, to produce a single enantiomer of compounds of formula 4-7 or 4-8 with high enantiomeric excess. See, for example, (a) J. Am. Chem. Soc. 1990, 112, 4077; (b) () Eur J. Biochem. 1992, 210, 475; (c) Appl. Environ. Microbiol. 2007, 73, 5676; (d) Appl. Microbiol. Biotechnol. 2016, 100, 8621.

Scheme 5 relates to the synthesis of acids of formula 5-6 (subtype of compounds of formula 1-1), 5-7 (subtype of compounds of formula 2-1) and 5-8 (subtype of compounds of formula 2-1), where R ^2c can be, for example, H, alkyl, C _3-4 cycloalkyl, etc. (see definitions of R ² or R ³ ). Aryl or heteroaryl halides of Formula 5-1 (where X ³ is I, Br, or in some cases Cl) can be purchased commercially or synthesized using methods known to those skilled in the art of synthesis. The aryl or heteroaryl halides of Formula 5-1 can be reacted with an appropriate metal-halogen exchange reagent, such as n-butyllithium, isopropylmagnesium chloride, or similar metal-containing bases, or magnesium metal, and quenched with a dicarbonyl compound of Formula 5- 3 to obtain compounds of formula 5-4. Alternatively, arenes or heteroarenes of formula 5-2 can be directly deprotonated with a similar strong base or reagents such as lithium diisopropylamide, lithium 2,2,6,6-tetramethylpiperidide, bis(2,2,6,6-tetramethylpiperidinyl)zinc or others variants thereof and can be reacted with dicarbonyl compounds of Formula 5-3 to produce compounds of Formula 5-4. Compounds of formula 5-4 can be treated with a strong acid such as hydrochloric acid, sulfuric acid, boron trifluoride diethyl etherate or other Bronsted or Lewis acids to give compounds of formula 5-5. Compounds of formula 5-5 can be treated with reducing agents such as silanes in the presence of acids or hydrogen and a metal catalyst such as palladium to produce compounds of formula 5-6. Alternatively, the compounds of formula 5-4 can also be treated with similar acids in the presence of a reducing agent such as silanes, or with hydrogen and a metal catalyst such as palladium, to produce acids of formula 5-6. Alternatively, compounds of formula 5-5 can be treated with hydrogen and metals such as ruthenium or rhodium or the like, and a chiral ligand or many other methods such as those described in Org. Chem. Front. 2014, 1, 155, for the selective formation of acids of formula 5-7 or 5-8 with high enantiomeric excess. Alternatively, the compounds of formula 5-5 can be converted using a biocatalyst such as ENE reductase (as described in ACS Catal. 2018, 8, 3532) or other methods to selectively form compounds of formula 5-7 or 5-8 with high enantiomeric excess. Alternatively, compounds of formula 5-6, which contain mixtures of enantiomers, can be separated using supercritical fluid or reverse phase chromatography with a chiral column, or they can be separated and isolated as a diastereomeric salt with the appropriate chiral acid under conventional separation conditions to give compounds of general formula 5 -7 or 5-8.

Scheme 6 describes some other methods for the synthesis of acids of formulas 1-1 and 2-1. Compounds of Formula 6-1 can be deprotonated using strong bases and acylated with carbon dioxide or a carbonyl compound of Formula 6-2 (where LG ¹ is a leaving group such as a chloride or alkoxide and PG ¹ is a protecting group as described above) with obtaining compounds of formula 6-3. Compounds of Formula 6-3 can be deprotonated using strong bases and treated with alkylating agents to produce compounds of Formula 6-4 in a manner similar to that described above for converting compounds of Formula 3-2 to compounds of Formula 3-3. Compounds 6-4 can be treated under hydrolysis conditions to produce compounds of formula 1-1 in a manner similar to that described above for converting compounds of formula 3-3 to compounds of formula 2-1, or with a metal catalyst such as palladium on carbon and hydrogen when PG ¹ is a benzyl group, or an acid, where PG ¹ can be separated as a stable cation or can be removed to give compounds of formula 1-1. Alternatively, the order of the steps may be reversed so that the compounds of Formula 6-3 are hydrolyzed to form the compounds of Formula 6-5 followed by alkylation using conditions similar to those described to yield compounds of Formula 1-1. Alternatively, the compounds of formula 6-4 can be treated under biocatalytic conditions, such as esterase enzymes, to produce acids of formula 2-1 with high enantiomeric excess. Alternatively, the compounds of formula 6-6 can be treated with a strong acid such as hydrochloric acid or sulfuric acid in the presence of an alcohol such as methanol or ethanol to give compounds of formula 6-3. Alternatively, compounds of Formula 6-6 can be alkylated to produce compounds of Formula 6-7 using a process similar to that described for converting compounds of Formula 6-3 to compounds of Formula 6-4. Alternatively, the compounds of formula 6-7 can be directly hydrolyzed to form acids of formula 1-1 using either a strong acid such as hydrochloric acid or sulfuric acid, or a strong base such as sodium hydroxide, potassium hydroxide or lithium hydroxide, in the presence of water . Alternatively, compounds of formula 6-8 (where LG ² represents a leaving group such as Cl, Br, I, OMs, OTs or others) can be treated with cyanide sources such as sodium cyanide, trimethylsilyl cyanide or others to obtain compounds of formula 6-6. Compounds of formula 6-8 can be purchased commercially or synthesized by various methods as described in the literature, or, when LG ² is, for example, Br or Cl, by reacting compounds of formula 6-1 with a halogenating electrophile such as N-bromosuccinimide , bromine or the like, using a radical initiating activator such as 2,2'-azobisisobutyronitrile, light or other reagents. Compounds of formula 6-12 (a subtype of compounds of formula 6-8 where R ² is H) can be converted into all of the analogous intermediates and derivatives of 6-8 using similar methods. Compounds of formula 6-14 can be treated with base and alkylating agents as described for the conversion of 6-3 to 6-4 to give compounds of formula 1-1. Compounds of formula 6-11 can be purchased commercially or synthesized using methods described in the literature. Compounds of formula 6-9 can be oxidized using an oxidizing reagent such as potassium permanganate, also to form compounds of formula 6-11. Compounds of formula 6-11 can be subjected to a homologation reaction using any number of methods described in the literature, such as the Arndt-Eistert reaction (using an activating reagent such as thionyl chloride, ethyl chloroformate, or others; then a diazomethane reagent; a silver salt such as benzoate silver, silver oxide, or the like; and a nucleophile such as water or alcohol), or other methods described in the literature, such as those described in J. Org. Chem. 2001, 66, 5606, to obtain compounds of formula 6-10. Acids of formula 1-1, which contain mixtures of enantiomers, can be separated using supercritical fluid or reverse phase chromatography with a chiral column, or they can be separated as a diastereomeric salt with the corresponding chiral acid under classical separation conditions, as described in Org. Process Res. Dev. 2011, 15, 53, or the undesired enantiomer can be converted to an ester using biocatalysis as described in Adv. Synth. Cat al., 2009, 351, 2333 (see also J. Org. Chem. 2003, 68, 7234), and resolve to give acids of formula 2-1 with high enantiomeric excess.

Scheme 7 describes the synthesis of compounds of formula 7-3, 7-4, 7-7, 7-8, 7-9 and 7-10 (where Q1 can represent any fragments of compounds that are described in formula I, Ia, II or Schemes 3-b), which can be used as any of the intermediates already described above, if necessary, and these substituents can be introduced at many points during the synthesis described in Schemes 3-6. Compounds of formula 7-1 (where PG ¹ has the meaning described above) can be subjected to a deprotection procedure using dealkylating conditions such as trimethylsilyl iodide, sodium methanethiolate or others, strong acids such as hydrobromic acid, boron tribromide, or, when PG ¹ represents a benzyl group, palladium or corresponding metals and hydrogen gas can be used to form compounds of formula 7-2. Compounds of Formula 7-2 can be reacted with difluoromethyl sources such as difluorohaloacetates or (bromodifluoromethyl)trimethylsilane to produce compounds of Formula 7-3. Compounds of Formula 7-2 can also be reacted with trifluoromethyl sources such as difluorohaloacetates, with the addition of an electrophilic fluorine source such as Selectfluor™, trifluoromethyl halides, or through a xanthan intermediate that can be treated with XtalFluor® and an electrophilic fluorine source such as N-fluorobenzenesulfonimide or 1, 3, 5-trichloro-1,3,5-triazinan-2,4,6-trione (TCCA) (as described in J. Org. Chem. 2019, 84, 15776) or others, to give the compounds formulas 7-4. Compounds of Formula 7-5 (where LG3 may be Cl, Br, I, OTf, or others) can be treated with a source of nucleophilic vinyl, such as vinyl boronate, vinyl stannane, or others, using palladium-catalyzed cross-coupling conditions described in the literature. to obtain compounds of formula 7-6. Compounds of formula 7-6 can be subjected to oxidative cleavage to the aldehyde using reagents such as ozone with triphenylphosphine or dimethyl sulfide, osmium tetroxide (or ruthenium trichloride) and sodium periodate or others to give compounds of formula 7-7. A compound of Formula 7-7 can be reacted with nucleophilic difluoromethylation sources such as Deoxo-Fluor® or XtalFluor® and appropriate reagents to produce compounds of Formula 7-8. Compounds of formula 7-5 can be treated with alcohols under SNAr conditions or cross-coupling using palladium and various ligands to give compounds of formula 7-9 [where R ⁸ is, for example, C _1-4 alkyl (such as methyl) or C _{1- 4} haloalkyl (such as C ₁ fluoroalkyl)]. Compounds of formula 7-5 can also be reacted with amines under the same conditions to give compounds of formula 7-10 [wherein R ⁶ and R ⁷ are each independently C _1-4 alkyl (such as methyl), or R ⁶ and R ⁷ together with the carbon atom to which they are bonded form cyclopropyl].

Scheme 8 describes the synthesis of compounds of formulas 1-2 and 1-3. Compounds of Formula 8-1 (wherein PG ⁴ may be benzyl, l-methoxybenzyl, t-butoxycarbonyl, benzyloxycarbonyl, acetyl, benzoyl, or other conventional nitrogen protecting groups; PG ⁵ may be the same as PG ⁴ or may be any of such protecting groups that can be removed orthogonally) can be halogenated using electrophilic halogenating reagents such as dibromohydantoin, N-bromosuccinimide, N-chlorosuccinimide, bromine, iodine, or the like, to give compounds of formula 8-3 (where X ⁴ may be Cl, Br or I). Compounds of formula 8-3 can be reacted with a source of diboron [such as tetrahydroxydiboron, bis(neopentylglycolate)diboron (5,5,5',5'-tetramethyl-2,2'-bi-1,3,2-dioxaborinan) or bis(pinacolate)diboron (4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi-1,3,2-dioxaborolane)], a source of di-tin, such as bis(tributyltin) or the like, a strong metal base such as isopropyl magnesium chloride, then a zinc source such as zinc dichloride or the like to give compounds of formula 8-2 (wherein M ¹ may be boronic acid , boronate, organotin compound, organozinc compound, or other metal capable of reacting under C-C cross-coupling conditions) and isolation if stable, or direction into another reaction if desired. Compounds of formula 8-2 can be reacted with compounds of formula 8-9 (where X ⁵ is Cl, Br, I, OTf, or others) under C-C cross-coupling conditions such as Suzuki reactions (M ¹ = boron), Stille (M ¹ =tin), Negishi (M ¹ =zinc halide), Kumada (M ¹ =magnesium halide), or others, to obtain compounds of formula 8-4. Alternatively, compounds of formula 8-3 and 8-10 can be reacted in the same manner as 8-2 and 8-9, with the nucleophile and electrophile returned to the cross-coupling reaction, to yield compounds of formula 8-4. Alternatively, in some cases, compounds of formula 8-1 can also be reacted under CH activation/direct arylation conditions with compounds of formula 8-9 to directly form compounds of formula 8-4. The PG ⁴ and PG ⁵ group of compounds of formula 8-4 can be removed using suitable deprotection conditions such as acid or hydrogenolysis or the like to obtain compounds of formula 1-2. It should be noted that when compounds of formula 8-1, 8-2, 8-3, 8-4 or 1-2 contain mixtures of stereochemistry or are racemic, they can be separated into individual enantiomers using supercritical fluid or reverse phase chromatography with chiral column or as a diastereomeric salt with the corresponding chiral acid under classical separation conditions and isolated to give compounds of formula 8-5, 8-7, 8-6, 8-8 or 1-3, respectively, with high enantiomeric excess. Alternatively, compounds of formula 8-5, 8-7, 8-6 and 8-8 can be reacted under the same conditions as their analogous intermediates from this scheme, without modifying the conditions leading to the formation of compounds of formula 1-3.

Scheme 9 relates to the synthesis of compound of formula 9-13. Compounds of formula 9-1 (where X ⁷ is more reactive than X ⁶ ; e.g., X ⁷ =Br, X ⁶ =Cl, or X ⁷ =I, X ⁶ =Br or Cl, or other similar combinations) can be reacted with a compound of formula 9-2 under Sonogashira reaction conditions using a copper and palladium catalyst to produce compounds of formula 9-3. Compounds of formula 9-3 can be treated with various palladium, platinum or rhodium catalysts (carbon or alumina or free) and hydrogen, trialkylsilanes, formic acid to obtain compounds of formula 9-8. Compounds 9-8 can be treated using SNAr type conditions or palladium or copper with suitable ligands under conventional CN cross-coupling conditions to give compounds of Formulas 9-4. Under the same conditions, with certain PG ⁵ groups such as carbamate and a stronger base such as sodium or potassium t-butoxide, compounds of formula 9-8 can be directly converted to compounds of formula 9-6. Alternatively, compounds of formula 9-9 (wherein R ¹¹ may be an arene such as phenyl, or an alkyl group such as ethyl or butyl, or an alcohol such as ethanol, or the like; and (Xs)" may be OMs ^- , OTs ^- , OTf ^- , Cl ^- , Br ^- , I ^- or the like) and compounds of formula 9-10 can be reacted together under Wittig reaction conditions (as described in Tetrahedron Lett. 2007, 48, 3359) or similar conditions with bases such as potassium carbonate, sodium t-butoxide, n-butyllithium or similar bases to give compounds of formula 9-11.Compounds of formula 9-11 can be converted to compounds of formula 9-8 using conditions similar to those transformations described for compounds of formula 9-3 to obtain compounds of formula 9-8.Alternatively, compounds of formula 9-10 can be converted to compounds of formula 9-12 using a suitable methylene-containing Wittig salt in a manner similar to the conversion of 9-10 to 9-11 Alternatively, compounds of formula 9-11 can be reacted under light-induced redox isomerization conditions using catalysts such as iridium or others, suitable ligands and a blue LED to produce compounds of formula 9-7. Alternatively, the conversion of compounds of formula 9-11 can be accomplished by reacting under the same redox conditions under the influence of light with a second catalyst, usually palladium, added to effect cyclization after isomerization, to give compounds of formula 9-5. Alternatively, compounds of formula 9-3 can be treated with poisoned catalysts such as Lindlar catalyst (eg, the methods described in J. Org. Chem. 2001, 66, 3634) or palladium on barium sulfate with a source of hydrogen, or the methods described in Tetrahedron Lett. 2008, 49, 2839, to obtain compounds of formula 9-7. Alternatively, compounds of formula 9-7 can be treated under hydrogenation conditions similar to those described for converting compounds of formula 9-11 to 9-8 to give compounds of formula 9-8. Alternatively, compounds of formulas 9-10 and 9-2 can be interconverted using alkyne formation conditions such as the Corey-Fuchs reaction or others to yield compounds of formula 9-2, or treated under oxidative cleavage conditions to yield compounds of formula 9- 10. Alternatively, compounds of formula 9-7 can be reacted under conditions similar to those described for converting compounds of formula 9-8 to compounds of formula 9-6 to give compounds of formula 9-5. Compounds of formula 9-5 can be reacted under conditions similar to those for converting compounds of formula 9-11 to compounds of formula 9-8 to give compounds of formula 9-4, 9-13 or 9-6 depending on the choice of protecting groups used. Alternatively , compounds of formula 9-5 can be reacted under standard conditions to remove PG ⁵ to give compounds of formula 9-14. Compounds of Formula 9-14 can then be reacted under conditions similar to those for converting compounds of Formula 9-5 to compounds of Formula 9-6 to give compounds of Formula 9-6 or 9-13 depending on the choice of protecting group. Alternatively, compounds of formula 9-12 can be converted to compounds of formula 9-11 using Hec's cross-coupling reaction conditions with compounds of formula 9-1. Alternatively, compounds of formula 9-12 and 9-1 can be converted to compounds of formula 9-15 using SNAr or CN cross-coupling conditions (where X ⁶ is more reactive than X ⁷ , e.g. X ⁷ =Cl, X ⁶ = Cl or Br, or X ⁷ =Br, X ⁶ =Br or I, or other similar combinations). Compounds of formula 9-15 can be reacted under conditions similar to those described for converting compounds of formula 9-12 to compounds of formula 9-11 to give compounds of formula 9-5.

Scheme 10 describes the synthesis of a compound of formula 10-11, a subtype of compound of formula 9-13, where the stereochemistry is determined. All of the transformations shown can be performed as described for the analogous compounds and intermediates described in Scheme 9 and do not require modification or use of different conditions.

Scheme 11 describes the synthesis of compounds of formula 11-6 and 11-7 (a subtype of compounds of formulas 9-2 and 10-1, respectively, where PG ⁷ is a protecting group that allows the adjacent nitrogen to remain nucleophilic, such as benzyl, p-methoxybenzyl, or etc., or possibly the absence of a protecting group). Compounds of formula 11-1 can be purchased commercially or synthesized according to methods described in the literature and can be reacted with compounds of formula 11-2 (where PG ⁶ is trimethylsilyl or other suitable alkyne protecting group) that have been deprotonated with a base such as potassium t-butoxide, lithium diisopropylamide, sodium hydride, n-butyllithium, zinc metal or magnesium to give the compound of formula 11-3. Compounds of Formula 11-3 can then be deprotected to produce a terminal alkyne using reagents such as tetrabutylammonium fluoride, potassium carbonate, potassium hydroxide, or the like, to yield compound of Formula 11-4. The hydroxyl of compounds of formula 11-4 can be activated to convert to a leaving group OR ⁹ (wherein R ⁹ is acetyl, benzoyl, t-butoxycarbonyl, dialkyl phosphate [P(O)(OAlk) ₂ ], or the like} using acetyl chloride , benzoyl chloride, other acyl halides, other suitably activated acids or other activating groups such as halogen formates, dialkyl halophosphates or the like, and a base such as triethylamine, N,iV-diisopropylethylamine, pyridine, 4-(dimethylamino)pyridine or the like. , to obtain activated compounds of formula 11-5. Compounds of formula 11-5 can be reacted with amines protected by p-methoxybenzyl, benzyl, or the like, in a reaction catalyzed by copper(I) chloride, copper(I) bromide (see J . Org. Chem. 2013, 78, 5647), ruthenium catalysts (see New J. Chem. 2011, 35, 2427), etc., to obtain compounds of formula 11-6. If the compounds of formula 11-6 contain mixtures stereochemistry or are racemic, they can be separated into individual enantiomers using supercritical fluid or reverse phase chromatography with a chiral column or as a diastereomeric salt with the appropriate chiral acid under classical separation conditions and isolated to give compounds of formula 11-7 with high enantiomeric excess.

Scheme 12 describes the synthesis of compounds of formula 9-1 and 9-9 (where R11 can represent alkyl groups, aryl groups, alkoxy groups, or combinations thereof, or an oxide variant thereof). Compounds of formula 12-1 (which can be purchased commercially or synthesized from 12-6 or other methods described in the literature) can be treated with a reducing agent such as aluminum-based hydrides (lithium aluminum hydride, sodium bis(2-methoxyethoxy)aluminum dihydride, diisobutylaluminum hydride or others) or borohydrides (such as lithium borohydride, sodium borohydride, or others), to obtain compounds of formula 12-3. Alternatively, compounds of formula 12-2 (which can be purchased commercially or formed from compounds of formula 12-1 using standard hydrolysis conditions or other methods described in the literature) can be converted using the same reagents, but also using borane reagents or borane derivatives to obtain compounds of formula 12-3. The OH group of compounds of Formula 12-3 can be activated to become a leaving group (LG ⁴ , which may be OMs, OTs, OTf, Cl, Br, I, or others) using a suitable reagent such as methanesulfonyl chloride, p-toluenesulfonyl chloride , trifluoromethanesulfonic anhydride, phosphorus oxychloride or thionyl chloride, phosphorus oxybromide or phosphorus tribromide, iodine with triphenylphosphine or imidazole, acids such as hydrobromic acid or hydrochloric acid, or using a combination of methods such as methanesulfonyl chloride followed by sodium iodide, sodium chloride, sodium bromide, potassium iodide, potassium chloride, potassium bromide, or the like, to obtain compounds of formula 12-4. Alternatively, the compounds of formula 12-5 can be halogenated under radical halogenation conditions, such as those described for the conversion of compounds 6-1 to 6-8, to give compounds of formula 12-4. A compound of formula 12-4 can be reacted with a compound of formula 12-9 (eg, triphenylphosphine, triethylphosphine, triethylphosphite, or other phosphorus nucleophiles) to produce compounds of formula 9-9. Compounds of formula 12-6 can be nitrated under standard nitration conditions, such as fuming nitric acid, to produce compounds of formula 12-7. The nitro group of compounds of formula 12-7 can be reduced to an amine using various conditions, such as palladium on carbon with hydrogen, zinc or iron with acetic or hydrochloric acid, tin(II) chloride, or others, to give compounds of formula 12-8 . Compounds of formula 12-8 can be treated with sodium nitrite or isoamyl nitrite with hydrobromic acid, potassium bromide, potassium iodide, or other standard Sandmeyer reaction conditions to give compounds of formula 9-1. Compounds of formula 9-1 can be treated using carbonylation conditions such as palladium with a suitable ligand such as 1,1'-bis(diphenylphosphino)ferrocene, a source of carbon monoxide and an alcohol such as ethanol or methanol, or can be treated using conditions metal-halogen exchange and quenching with an acyl source such as diethyl carbonate, carbon dioxide, ethyl chloroformate, or the like, to produce compounds of formula 12-1.

Scheme 13 describes a method for the synthesis of compounds of formula 9-10. Compounds of formula 13-1 (where PG ⁸ can be any C-linked alkyl or aryl, and which can be purchased commercially or synthesized using methods described in the literature) can be treated under hydroxyl group removal conditions, for example using methanesulfonyl chloride or l-toluenesulfonyl chloride, as described in Org. Lett. 2016, 18, 1812, or using other standard conditions to obtain compounds of formula 13-2. Compounds of Formula 13-2 can be reacted in a 3+2 cycloaddition reaction with commercially available compounds of Formula 13-3 to produce compounds of Formula 13-4. Compounds of formula 13-4 can be reduced directly to compounds of formula 9-10 using conditions such as diisobutylaluminium hydride, or other reducing agents with which excessive reduction can be avoided. Alternatively, compounds of formula 13-4 can be reduced to compounds of formula 13-5 using conditions similar to those described for converting compounds of formula 12-1 to 12-3. The compounds of formula 13-5 can then be oxidized using a number of well-known reagents, such as chromium Collins reagent, periodinane Dess-Martin reagents, Parick-Döring reagent, other activated DMS0-based reagents such as Swern reagents, or many others, to produce compounds of formula 9-10. Alternatively, compounds of formula 13-8 can be treated with lithium diisopropylamide, lithium bis(trimethylsilyl)amide, n-butyllithium or many other similar strong bases and suitable acylating reagents such as ethyl chloroformate, ethyl cyanoformate or diethyl carbonate to give compounds of formula 13-9 (wherein PG ⁹ may be the same as PG ⁸ or may be a different alkyl or aryl group so that orthogonal removal of this group under selective conditions is possible). The compounds of formula 13-9 can be selectively hydrolyzed using one equivalent of a base such as sodium hydroxide or lithium hydroxide or many others, or using a selective PG ⁹ such as benzyl, which can be removed by treatment with palladium on the carbon and hydrogen, to give the compounds formulas 13-10. Compounds of formula 13-10 can be converted to compounds of formula 13-4 using reactions such as the Curtius rearrangement (as described in Org. Biomol. Chem. 2018, 16, 2006), or other similar reactions that provide rearrangement of the acid or corresponding acyl group to a dehomologated amine or protected amine, such as the Hoffmann rearrangement, Lossen rearrangement or Schmidt reaction.

Scheme 14 describes a method for the synthesis of compounds of formula 10-8 (subtype 9-10, where the stereochemistry is determined) and corresponding intermediates. Racemic variants or mixtures of compounds of formula 13-4 can be separated into individual enantiomers using supercritical fluid chromatography or reverse phase chromatography with a chiral column, or, when PG ⁴ or PG ⁵ is a protecting group that does not remove the basicity of the nitrogen to which it is attached, can also be resolved using a chiral acid under classical separation conditions to give compounds of formula 14-4. Alternatively, the compounds of formula 13-9 can be subjected to various biocatalytic conditions, such as Esterase ECS03 (AB 5035 74) from Enzymlcals, or the conditions described in Tetrahedron: Asymmetry 1998, 9, 2 663, to form compounds of the general formula 14-1 ( subtype of compounds of formula 13-10). Compounds of general formula 14-1 and 14-4 can be converted to their analogous compounds described in Scheme 13 using the conditions described, without any need for modification or change in reaction conditions.

Scheme 15 describes the synthesis of compound 15-4 (a subtype of compounds of formula 8-4, where X ¹ represents CH-CH ₃ ). Compounds of formula 11-1 can be reacted with ammonia and an allylboron reagent as described in Chem. Commun. 2005, 44, 5551, to obtain compounds of formula 15-1. Compounds of Formula 15-1 can be reacted in a manner similar to that described for converting compounds of Formula 9-12 to 9-15 to produce compounds of Formula 15-2. Compounds 15-2 can be reacted in a manner similar to the conversion of compounds of formula 9-15 to 9-5 to give compounds of formula 15-3 while rearranging to an internal olefin as shown. Compounds of Formula 15-3 can be converted to compounds of Formula 15-4 using methods similar to those described for converting compounds of Formula 9-5 to 9-4. Alternatively, compounds of formula 15-2 can be reacted using ozonolysis conditions in the presence of sodium borohydride or other oxidative cleavage conditions to produce compounds of formula 15-7. Compounds of formula 15-7 can be reacted under hydroxyl group removal conditions to an olefin, such as using methanesulfonyl chloride or l-toluenesulfonyl chloride followed by a strong base, or using Grieco elimination conditions with an aryl selenocyanate in the presence of a trialkylphosphine, to give compounds of formula 15-8 ( which is a subtype of compounds of formula 9-15, where PG ⁵ represents H).

Scheme 16 describes the synthesis of compounds of formula 16-3 (where Y ⁷ represents N or CH), 16-7, 16-11 and 16-14, which are all subtypes of 8-9, which may not be commercially available. Compounds of Formula 16-1 can be reacted with a source of electrophilic halogen in a manner similar to the conversion of compounds of Formula 8-1 to 8-3 to produce compounds of Formula 16-2. Compounds of formula 16-2 can be reacted under conditions similar to those for converting compounds of formula 7-2 to 7-3 (when R ¹² is H) or compounds of formula 7-2 to 7-4 (when R ¹² is F), to obtain compounds of formula 16-3. Compounds of formula 16-4 (where X ⁹ may be a halogen, which is the same as X ⁵ or may be more reactive, thus X ⁹ is Br when Xs is Cl, or X ⁹ is I when X ⁵ is Br or Cl) can be reacted under Chan-Lam reaction conditions with cyclopropylboronic acid (when R ¹³ is cyclopropyl) and a copper source such as copper(II) acetate or the like and suitable ligands , such as 2,2'-bipyridine, and any number of bases, such as carbonates or amines, and a co-oxidant, such as oxygen, which may be added or supplied from air, to give compounds of formula 16-5. Compounds of formula 16-5 (which can be purchased commercially, for example when R ¹³ is methyl, or can be prepared as described herein or in the literature) can be reacted under metal-halogen exchange conditions such as isopropyl magnesium chloride, n-butyllithium, magnesium, or the like, and quench with a carbonyl source such as N,N-dimethylformamide, morpholine-4-carbaldehyde, or the like, to obtain compounds of formula 16-6. Compounds of formula 16-6 can be reacted under conditions similar to those used to convert compounds of formula 7-7 to 7-8 to give compounds of formula 16-7. Compounds of Formula 16-4 can be reacted with 4-halo-1-butene in the presence of a base such as potassium carbonate, sodium bicarbonate, sodium hydride, lithium diisopropylamide, or the like to produce compounds of Formula 16-8. Compounds of formula 16-8 can be reacted under Heck reaction conditions as described for converting compounds of formula 9-15 to 9-5 to give compounds of formula 16-9. Compounds of Formula 16-9 can be reacted in several steps in the same manner as described for the sequence of converting compounds of Formula 7-6 to 7-7 to 7-8 to give compounds of Formula 16-10 and 16-11. Compounds of formula 16-12 (where X ¹⁰ may be Cl, Br or I, OTf or others) can be reacted with palladium on carbon or other conventional catalysts and deuterium gas (or other deuteride source such as deuterated formate, under conditions transfer hydrogenation) to obtain compounds of formula 16-13. Compounds of formula 16-13 can be reacted under Sandmeyer reaction conditions as described for converting compounds of formula 12-8 to 9-1 to give compounds of formula 16-14. Alternatively, compounds of formula 16-15 can be reacted under Sandmeyer reaction conditions as described for the conversion of compounds of formula 12-8 to 9-1.

Scheme 17 describes a method for the synthesis of compounds of Formula 17-5, which are a subtype of compounds of Formula 8-4, wherein R ¹ is a tetrazole substituted with an R ¹⁴ group, which may be an optionally substituted alkyl or aryl group. Compounds of formula 17-1 can be reacted using a conversion method similar to that described for the synthesis of compounds of formula 7-5 to 7-6 and 7-7 to give compounds of formula 17-2 and 17-3. Alternatively, compounds of Formula 17-1 can be directly converted to compounds of Formula 17-3 in a manner similar to the method for converting compounds of Formula 16-5 to compounds of Formula 16-6. Compounds of formula 17-3 can be reacted with substituted hydrazines under standard condensation conditions using acid or alkaline catalysis to give compounds of formula 17-4. Compounds of formula 17-4 can be reacted with diazo compounds such as diethyl or di-tert-butyl azodicarboxylate in the presence of hypervalent iodine sources such as [bis(trifluoroacetoxy)iodo]benzene or others to produce compounds of formula 17- 5.

A detailed description of the individual reaction steps is given below in the Examples section. Those skilled in the art will appreciate that other synthetic routes can be used to synthesize the compounds. Although specific starting materials and reagents are discussed below, they can be easily replaced by other starting materials and reagents to obtain different derivatives and/or reaction conditions. In addition, many of the compounds prepared by the methods described below can be further modified in light of the present disclosure using conventional chemical methods well known to those skilled in the art.

Combined products

The compounds of the present invention can be administered alone or in combination with one or more additional therapeutic agents. By “administered in combination” or “combination therapy” is meant that a compound of the present invention and one or more additional therapeutic agents are administered simultaneously to the mammal being treated. When administered in combination, each component may be administered simultaneously or sequentially in any order at different times. Thus, each component can be administered separately, but close enough in time to provide the desired therapeutic effect. The phrases "co-administered", "co-administered", "simultaneous administration" and "administered simultaneously" mean that the compounds are administered in combination. Thus, the methods of prevention and treatment described herein include the use of combination agents.

The combination agents are administered to the mammal in a therapeutically effective amount. By “therapeutically effective amount” is meant an amount of a compound of the present invention that, when administered to a mammal alone or in combination with an additional therapeutic agent, is effective in treating the target disease/disorder/condition (e.g., cachexia, anorexia, anorexia nervosa, nausea, vomiting, retention development, sarcopenia, muscle wasting, weakness, osteoporosis, bone loss, pain, anxiety, depression or hypertension).

In some embodiments, a compound of the present invention may be coadministered with one or more other agents, such as orlistat, TZD and other insulin sensitizers, FGF21 analogs, metformin, omega-3 ethyl esters (e.g., Lovasa), fibrates, HMG-CoA reductase inhibitors, ezetimibe, probucol, ursodeoxycholic acid, TGR5 agonists, FXR agonists, vitamin E, betaine, pentoxifylline, CB1 antagonists, carnitine, N-acetylcysteine, reduced glutathione, lorcaserin, combination of naltrexone with buproprion, SGLT2 inhibitors (including dapagliflozin, canagliflozin, empagliflozin, tofogliflozin, ertugliflozin, ASP-1941, THR1474, TS-071, ISIS388626 and LX4211, and those described in WO 2010023594), phentermine, topiramate, GLP-1 receptor agonists, GIP receptor agonists, two nal agonists GLP-1 receptor/glucagon receptor (eg, OPK88003, MEDI0382, JNJ-64565111, NN9277, BI 456906), dual GLP-1 receptor/GIP receptor agonists [eg, tirzepatide (LY3298176), NN9423], angiotensin receptor blockers, acetyl inhibitor -CoA carboxylase (ACC), BCKDK inhibitor, ketohexokinase (KNK) inhibitor, ASK1 inhibitors, branched chain alpha-keto acid dehydrogenase kinase inhibitors (BCKDK inhibitors), CCR2 and/or CCR5 inhibitors, PNPLA3 inhibitors, DGAT1 inhibitors, DGAT2 inhibitors, analog FGF21, FGF19 analogs, PPAR agonists, FXR agonists, AMPK activators [eg, ETC-1002 (bempedoic acid)], SCD1 inhibitors, or MPO inhibitors.

Examples of GLP-1 receptor agonists include liraglutide, albiglutide, exenatide, albiglutide, lixisenatide, dulaglutide, semaglutide, HM ¹ 5211, LY3298176, Medi-0382, NN-9924, TTP-054, TTP-273, efpeglenatide, agents described in WO 2018109607, described in PCT/IB 2019/054867, filed June 11, 2019, and described in PCT/IB2019/054961, filed June 13, 2019, including the following connections:

2-({4-[2-(4-chloro-2-fluorophenyl)-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[(2S)-oxetan-2-ylmethyl ]-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(4-chloro-2-fluorophenyl)-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-7-fluoro-1-[(2S)-oxetane -2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[(2S)-2-(4-chloro-2-fluorophenyl)-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[(2S)-oxetane -2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[(2S)-2-(4-chloro-2-fluorophenyl)-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-7-fluoro-1-[( 2S)-oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[(2S)-oxetane -2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(4-cyano-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[(2S)-oxetane -2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(5-chloropyridin-2-yl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[(2S)-oxetane -2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-3-(1,3-oxazole -2-ylmethyl)-3N-imidazo[4,5-b]pyridine-5-carboxylic acid;

2-({4-[2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[(1-ethyl- 1H-imidazol-5-yl)methyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-(1,3-oxazole -4-ylmethyl)-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-(pyridin-3-ylmethyl )-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-(1, 3-o xa zol-5-ylmethyl)-1H-benzimidazol-6-carboxylic acid;

2-({4-[2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[(1-ethyl- 1H-1,2,3-triazol-bil)methyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-(1,3-oxazole -2-ylmethyl)-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(4-chloro-2-fluorophenyl)-7-fluoro-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[( 2S)-oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(4-cyano-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-(1,3-oxazole -2-ylmethyl)-1H-benzimidazole-6-carboxylic acid;

2-({4-[(2S)-2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-7-fluoro- 1-[(2S)-oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[(2S)-2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[( 2S)-oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[(2S)-2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-7-fluoro- 1-[(2S)-oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[(2S)-2-(4-cyano-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[( 2S)-oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[(2S)-2-(5-chloropyridin-2-yl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[( 2S)-oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[(2S)-2(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[(1 -ethyl-1H-imidazol-5-yl)methyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[(2R)-2-(4-chloro-2-fluorophenyl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[( 1-ethyl-1H-imidazol-5-yl)methyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(5-chloropyridin-2-yl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[(2S)-oxetane -2 -ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[(2S)-2-(5-chloropyridin-2-yl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[( 2S)-oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[(2R)-2-(5-chloropyridin-2-yl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[( 2S)-oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-({4-[2-(5-chloropyridin-2-yl)-2-methyl-1,3-benzodioxol-4-yl]piperidin-1-yl}methyl)-1-[(2S)-oxetane -2-ylmethyl]-1H-benzimidazole-6-carboxylic acid, DIAST-X ² ;

2-[(4-{2-[(4-chloro-2-fluorobenzyl)oxy]pyridin-3-yl}piperidin-1-yl)methyl]-1-[(2S)-oxetan-2-ylmethyl]- 1H-benzimidazole-6-carboxylic acid;

2-[(4-{2-[(4-chloro-2-fluorobenzyl)oxy]pyridin-3-yl}piperidin-1-yl)methyl]-1-(1,3-oxazol-2-ylmethyl)- 1H-benzimidazole-6-carboxylic acid;

2-[(4-{2-[(4-cyano-2-fluorobenzyl)oxy]pyridin-3-yl}piperidin-1-yl)methyl]-1-(1,3-oxazol-2-ylmethyl)- 1H-benzimidazole-6-carboxylic acid;

2-[(4-{2-[(4-cyano-2-fluorobenzyl)oxy]pyridin-3-yl}piperidin-1-yl)methyl]-1-[(2S)-oxetan-2-ylmethyl]- 1H-benzimidazole-6-carboxylic acid;

2-[(4-{3-[(4-chloro-2-fluorobenzyl)oxy]pyrazin-2-yl}piperidin-1-yl)methyl]-1-[(2S)-oxetan-2-ylmethyl]- 1H-benzimidazole-6-carboxylic acid;

2-(6-{6-[(4-cyano-2-fluorobenzyl)oxy]pyridin-2-yl}-6-azaspiro[2.5]oct-1-yl)-1-[(2S)-oxetane-2 -ylmethyl]-H-benzimidazole-6-carboxylic acid;

2-(6-{2-[(4-chloro-2-fluorobenzyl)oxy]-5-fluoropyrimidin-4-yl}-6-azaspiro[2.5]oct-1-yl)-1-[(2S)- oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-(6-{2-[(4-chloro-2-fluorobenzyl)oxy]-5-fluoropyrimidin-4-yl}-6-azaspiro[2.5]oct-1-yl)-1-(1,3- oxazol-2-ylmethyl)-1H-benzimidazol-6-carboxylic acid;

2-(6-{6-[(4-cyano-2-fluorobenzyl)oxy]-5-fluoropyridin-2-yl}-6-azaspiro[2.5]oct-1-yl)-1-[(2S)- oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-(6-{6-[(4-cyano-2-fluorobenzyl)oxy]-3-fluoropyridin-2-yl}-6-azaspiro[2.5]oct-1-yl)-1-[(2S)- oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-[(4-{2-[(4-chloro-2-fluorobenzyl)oxy]pyrimidin-4-yl}piperidin-1-yl)methyl]-1-[(2S)-oxetan-2-ylmethyl]- 1H-benzimidazole-6-carboxylic acid;

2-{[(2S)-4-{2-[(4-chloro-2-fluorobenzyl)oxy]-5-fluoropyrimidin-4-yl}-2-methylpiperazin-1-yl]methyl}-1-[( 2S)-oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid;

2-{[(2S)-4-{2-[(4-chloro-2-fluorobenzyl)oxy]pyrimidin-4-yl}-2-methylpiperazin-1-yl]methyl}-1-[(2S)- oxetan-2-ylmethyl]-1H-benzimidazole-6-carboxylic acid; And

2-[(4-{6-[(4-cyano-2-fluorobenzyl)oxy]pyridin-2-yl}piperidin-1-yl)methyl]-1-[(2S)-oxetan-2-ylmethyl]- 1H-benzimidazole-6-carboxylic acid, and pharmaceutically acceptable salts thereof.

Examples of ACC inhibitors include 4-(4-[(1-isopropyl-7-oxo-1,4,6,7-tetrahydro-1'H-spiro[indazol-5,4'-piperidin]-1'-yl) carbonyl]-6-methoxypyridin-2-yl)benzoic acid, gemcaben and firsocostat (GS-0976) and pharmaceutically acceptable salts thereof.

Examples of FXR agonists include tropifexor (2-[(1R,3R,55)-3-({5-cyclopropyl-3-[2-(trifluoromethoxy)phenyl]-1,2-oxazol-4-yl}methoxy)-8 -azabicyclo[3,2,1]octan-8-yl]-4-fluoro-1,3-benzothiazole-6-carboxylic acid), cilofexor (GS-9674), obeticholic acid, LY2562175, Met409, TERN-101 and EDP-305, and pharmaceutically acceptable salts thereof.

Examples of KNK inhibitors include [(1R,5S,6R)-3-{2-[(2S)-2-methylazetidin-1-yl]-6-(trifluoromethyl)pyrimidin-4-yl}-3-azabicyclo[3.1. 0]hex-6-yl]acetic acid and its pharmaceutically acceptable salts.

Examples of DGAT2 inhibitors include (S)-2-(5-((3-ethoxypyridin-2-yl)oxy)pyridin-3-yl)-N-(tetrahydrofuran-3-yl)pyrimidin-5-carboxamide [including its crystalline solid forms (Form 1 and Form 2)]. See US Patent No. 10071992.

Examples of BCKDK inhibitors include those described in US Serial No. 62/868057, filed June 28, 2019, and U.S. Serial No. 62/868,542 filed June 28, 2019, including the following connections:

5-(5-chloro-4-fluoro3-methylthiophen-2-yl)-1H-tetrazole;

5-(5-chloro-3-difluoromethylthiophen-2-yl)-1H-tetrazole;

5-(5-fluoro-3-methylthiophen-2-yl)-1H-tetrazole;

5-(5-chloro-3-methylthiophen-2-yl)-1H-tetrazole;

5-(3,5-dichlorothiophen-2-yl)-1H-tetrazole;

5-(4-bromo-3-methylthiophen-2-yl)-1H-tetrazole;

5-(4-bromo-3-ethylthiophen-2-yl)-1H-tetrazole;

5-(4-chloro-3-ethylthiophen-2-yl)-1H-tetrazole;

3-chloro-5-fluorothieno[3,2-b]thiophene-2-carboxylic acid;

3-bromo-5-fluorothieno[3,2-b]thiophene-2-carboxylic acid;

3-(difluoromethyl)-5-fluorothieno[3,2-b]thiophene-2-carboxylic acid;

5,6-difluorothieno[3,2-b]thiophene-2-carboxylic acid; And

3,5-difluorothieno[3,2-b]thiophene-2-carboxylic acid;

or pharmaceutically acceptable salts thereof.

In some embodiments, a compound of the present invention may be administered in conjunction with one or more antidiabetic agents. Suitable antidiabetic agents include insulin, metformin, GLP-1 receptor agonists (described herein above), acetyl-CoA carboxylase (ACC) inhibitor (described herein above), SGLT2 inhibitors (described herein above), monoacylglycerol inhibitors -O-acyltransferases, phosphodiesterase (PDE)-10 inhibitors, AMPK activators [e.g. ETC-1002 (bempedoic acid)], sulfonylureas (e.g. acetohexamide, chlorpropamide, diabinese, glibenclamide, glipizide, glyburide, glimepiride, gliclazide, glipentide, gliquidone, glizolamide, tolazamide, and tolbutamide), meglitinides, α-amylase inhibitors (eg, tendamistat, trestatin, and AL-3688), α-glucoside hydrolase inhibitor (eg, acarbose), α-glucosidase inhibitors (eg, adiposine, camiglibose , emiglitate, miglitol, voglibose, pradimycin-Q and salbostatin), PPARγ agonists (eg, balaglitazone, ciglitazone, darglitazone, englitazone, isaglitazone, pioglitazone and rosiglitazone), PPAR α/γ agonists (eg, CLX-0940, GW-1536, GW-1929, GW-2433, KRP-297, L-796449, LR-90, MK-0767, and SB-219994), protein tyrosine phosphatase-1B (PTP-1B) inhibitors [e.g., trodusquemine, hyrthiosal extract, and compounds disclosed in Zhang, S. et al., Drug Discovery Today, 12(9/10), 373-381 (2007)], SIRT-1 activators (eg, resveratrol, GSK2245840 or GSK184072), dipeptidyl peptidase IV (DPP-IV) inhibitors ( for example, those described in WO 2005116014, sitagliptin, vildagliptin, alogliptin, dutogliptin, linagliptin and saxagliptin), insulin secretagogues, fatty acid oxidation inhibitors, A2 antagonists, c-jun amino-terminal kinase (JNK) inhibitors, glucokinase activators (GKa ), such as those described in WO 2010103437, WO 2010103438, WO 2010013161, WO 2007122482, TTR-399, TTR-355, TTR-547, AZD1656, ARRY1403, MK-0599, TAK-329, AZD5658 or GK M-001, insulin, insulin mimetics, glycogen phosphorylase inhibitors (eg, GSK1362885), VPAC2 receptor agonists, glucagon receptor modulators such as those described in Demong, D.E. et al., Annual Reports in Medicinal Chemistry 2008, 43, 119-137, GPR119 modulators, especially agonists such as those described in WO 2010140092, WO 2010128425, WO 2010128414, WO 2010106457, Jones, R.M. et al., Annual Reports in Medicinal Chemistry 2009, 44, 149-170 (e.g., MBX-2982, GSK1292263, APD597 and PSN821), derivatives or analogues of FGF21, such as those described in Kharitonenkov, A. et al., Current Opinion in Investigational Drugs 2009, 10(4)359-364, TGR5 receptor modulators (also called GPBAR1), especially agonists such as those described in Zhong, M., Current Topics in Medicinal Chemistry, 2010, 10(4), 386-396 and INT777 , GPR40 agonists such as those described in Medina, J.C., Annual Reports in Medicinal Chemistry, 2008, 43, 75-85, including but not limited to TAK-875, GPR120 modulators, especially agonists, high-affinity nicotinic acid receptor activators (HM74A) and SGLT1 inhibitors such as GSK1614235. A further representative list of antidiabetic agents that can be combined with the compounds of the present invention can be found, for example, on page 28, line 35 to page 30, line 19 of WO 2011005611.

Other antidiabetic agents may include carnitine palmitoyltransferase enzyme inhibitors or modulators, fructose 1,6-biphosphatase inhibitors, aldose reductase inhibitors, mineralocorticoid receptor inhibitors, TORC2 inhibitors, CCR2 and/or CCR5 inhibitors, PKC isoform inhibitors (eg, PKCα, PKCβ, PKCγ) , fatty acid synthetase inhibitors, serine palmitoyltransferase inhibitors, modulators of GPR81, GPR39, GPR43, GPR41, GPR105, Kv1.3, retinol binding protein 4, glucocorticoid receptor, somatostatin receptors (eg, SSTR1, SSTR2, SSTR3, and SSTR5), PDHK2 inhibitors or modulators, or PDHK4, MAP4K4 inhibitors, IL1 family modulators, including IL1beta, RXRalpha modulators. In addition, suitable antidiabetic agents include the mechanisms listed in Carpino, P.A., Goodwin, B. Expert Opin. Ther. Pat., 2010, 20(12), 1627-51.

The compounds of the present invention can be co-administered with anti-heart failure drugs such as ACE inhibitors (eg, captopril, enalapril, fosinopril, lisinopril, perindopril, quinapril, ramipril, trandolapril), angiotensin II receptor blockers (eg, candesartan, losartan, valsartan) , angiotensin receptor neprilysin inhibitors (sacubitril/valsartan), I _f channel blocker ivabradine, beta blockers (eg, bisoprolol, metoprolol succinate, carvedilol), aldosterone antagonists (eg, spironolactone, eplerenone), hydralazine and isosorbide dinitrate, diuretics (eg , furosemide, bumetanide, torsemide, chlorothiazide, amiloride, hydrochlorothiazide, indapamide, metolazone, triamterene) or digoxin.

The compounds of the present invention may also be co-administered with cholesterol- or lipid-lowering agents, including the following illustrative agents: HMG CoA reductase inhibitors (e.g., pravastatin, pitavastatin, lovastatin, atorvastatin, simvastatin, fluvastatin, NK-104 (also known as itavastatin , or nisvastatin, or nisbastatin) and ZD-4522 (also known as rosuvastatin, or atavastatin, or visastatin); squalene synthetase inhibitors; fibrates (such as gemfibrozil, pemafibrate, fenofibrate, clofibrate); bile acid sequestrants (such as questran, colestipol, colesevelam); AST inhibitors; MTP inhibitors, lipoxygenase inhibitors, cholesterol absorption inhibitors (eg, ezetimibe), niacin (eg, niacin, niacor, sloniacin), omega-3 fatty acids (eg, epanova, fish oil, eicosapentaenoic acid) acid), cholesteryl ester transfer protein inhibitors (eg, obicetrapib) and PCSK9 modulators [eg, alirocumab, evolocumab, bococizumab, ALN-PCS (inclisiran)].

The compounds of the present invention can also be used in combination with antihypertensive agents, and such antihypertensive activity can be easily determined by those skilled in the art based on standard tests (eg, blood pressure measurements). Examples of suitable antihypertensive agents include: alpha-adrenergic blockers; beta blockers; calcium channel blockers (eg, diltiazem, verapamil, nifedipine and amlodipine); vasodilators (eg, hydralazine), diuretics (eg, chlorothiazide, hydrochlorothiazide, flumethiazide, hydroflumethiazide, bendroflumethiazide, methylchlorothiazide, trichloromethiazide, polythiazide, benzothiazide, ethacrynic acid, tricrinafen, chlorthalidone, torasemide, furosemide, musolimin, bumetanide , triamtrene, amiloride, spironolactone) ; renin inhibitors; ACE inhibitors (eg, captopril, zofenopril, fosinopril, enalapril, ceranopril, cilazopril, delapril, pentopril, quinapril, ramipril, lisinopril); AT-1 receptor antagonists (for example, losartan, irbesartan, valsartan); ET receptor antagonists (eg sitaxentan, atrsentan and the compounds disclosed in US Pat. Nos. 5,612,359 and 6,043,265); dual ET/AII antagonist (eg compounds disclosed in WO 00/01389); neutral endopeptidase (NEP) inhibitors; Vasopeptidase inhibitors (dual NEP-ACE inhibitors) (eg hemopatrylate and nitrates). An exemplary antianginal agent is ivabradine.

Examples of suitable calcium channel blockers (L-type or T-type) include diltiazem, verapamil, nifedipine and amlodipine and mibefradil.

Examples of suitable cardiac glycosides include digitalis and ouabain.

In one embodiment, a compound of the invention may be administered in conjunction with one or more diuretics. Examples of suitable diuretics include (a) loop diuretics such as furosemide (such as LASIX™), torsemide (such as DEMADEX™), bemetanide (such as BUMEX™) and ethacrynic acid (such as EDECRIN™); (b) thiazide type diuretics such as chlorotiazide (for example, Diuril ™, Esidrix ™ or Hydrodiuril ™), hydrochlorotiazide (e.g., Microzide ™ or ORETIC ™), Benztiazide, hydrophlimeetiazide (e.g., Saluron ™), Bendroflumeetiazid, methylly. Azid, Politiazid, trichlormethiazide and indapamide (such as LOZOL™); (c) phthalimidine-type diuretics such as chlorthalidone (such as HYGROTON™) and metolazone (such as ZAROXOLYN™); (d) quinazoline-type diuretics such as quinetasone; and (e) potassium-sparing diuretics such as triamterene (eg, DYRENIUM™) and amiloride (eg, MIDAMOR™ or MODURETIC™).

In another embodiment, a compound of the invention may be co-administered with a loop diuretic. In yet another embodiment, the loop diuretic is selected from furosemide and torsemide. In yet another embodiment, one or more compounds of Formula I or pharmaceutically acceptable salts thereof can be co-administered with furosemide. In yet another embodiment, one or more compounds of Formula I or pharmaceutically acceptable salts thereof may be co-administered with torsemide, which may optionally be a controlled or modified release form of torasemide.

In another embodiment, a compound of the invention may be co-administered with a thiazide-type diuretic. In yet another embodiment, the thiazide-type diuretic is selected from the group consisting of chlorothiazide and hydrochlorothiazide. In yet another embodiment, one or more compounds of Formula I or pharmaceutically acceptable salts thereof can be co-administered with chlorothiazide. In yet another embodiment, one or more compounds of Formula I or pharmaceutically acceptable salts thereof can be co-administered with hydrochlorothiazide.

In another embodiment, one or more compounds of Formula I or pharmaceutically acceptable salts thereof may be co-administered with a phthalimidine-type diuretic. In yet another embodiment, the phthalimidine-type diuretic is chlorthalidone.

Examples of suitable mineralocorticoid receptor antagonists include sprionolactone and eplerenone.

Examples of suitable phosphodiesterase inhibitors include: PDE III inhibitors (such as cilostazol); and PDE V inhibitors (such as sildenafil).

Those skilled in the art will appreciate that the compounds of the present invention may also be used in combination with other treatments for cardiovascular or cerebrovascular disease, including percutaneous coronary intervention, stenting, drug-eluting stents, stem cell therapy, and medical devices such as implanted pacemakers, defibrillators, or cardiac resynchronization therapy.

Particularly when provided in a single dosage form, there is a potential for chemical interactions between the combined active ingredients. For this reason, when the compound of the present invention and the second therapeutic agent are combined in a single dosage form, they are formulated in such a way that, although the active ingredients are combined in a single dosage form, physical contact between the active ingredients is minimized (i.e. reduced). For example, one active ingredient may be enteric coated. When one of the active ingredients is enteric coated, not only can contact between the combined active ingredients be minimized, but also the release of one of these components in the gastrointestinal tract can be controlled so that one of these components is not released in the stomach but is released in the intestine . One of the active ingredients may also be coated with a material that provides sustained release in the gastrointestinal tract and also serves to minimize physical contact between the combined active ingredients. In addition, the sustained release component may be further coated with an enteric coating such that release of the component occurs only in the intestines. Another approach involves formulating a combination product in which one component is coated with a sustained release and/or enteric release polymer and the other component is also coated with a polymer such as low viscosity hydroxypropyl methylcellulose (HPMC) or other suitable materials known in the art. techniques for further separation of active components. The polymer coating serves as an additional barrier to interaction with another component.

These, as well as other methods of minimizing contact between the components of the combination products of the present invention, whether administered in a single dosage form or administered in separate forms, but at the same time in the same way, will be apparent to those skilled in the art. the art when they become familiar with this disclosure.

In combination therapy treatment, the compounds of the present invention, as well as other drug therapies, are administered to mammals (eg, humans, men or women) by conventional means. The compound of formula I or a salt thereof is adapted for therapeutic use as agents that exhibit antagonism (including inhibition) of MC4R in mammals, in particular humans, and are thus useful in the treatment of various conditions (for example, those described herein ), which implies such an action.

Disease/disorder/condition that can be treated in accordance with the present invention includes, but is not limited to, cachexia (eg, cachexia associated with cancer, AIDS, congestive heart failure and/or chronic kidney disease); anorexia/anorexia nervosa (eg, geriatric anorexia, anorexia associated with chemotherapy and/or radiation therapy); nausea; vomiting; weight loss (eg, unintentional weight loss); developmental delay; sarcopenia; muscle atrophy; weakness; osteoporosis; bone diseases (eg, bone loss); pain; neuropathic pain; anxiety; depression; hypertension; eating disorders; obesity; sexual dysfunction; and inflammatory disease.

Administration of the compounds of the present invention can be accomplished by any method in which the compound of the present invention is delivered systemically and/or locally. These routes include oral, parenteral, intraduodenal, buccal, intranasal, etc. Typically, the compounds of the present invention are administered orally, but parenteral administration (eg, intravenous, intramuscular, subcutaneous or intramedullary) may be used, for example when oral administration is not appropriate for the target or when the patient is unable to swallow the drug.

For administration to human patients, the oral daily dose of the compounds of the present invention may be, for example, from 0.01 mg to 5000 mg depending, of course, on the route and frequency of administration, the disease state, the age and condition of the patient, etc. An oral daily dose in the range of 1 mg to 2000 mg (eg, 3 mg to 2000 mg) may be used. As another example, the oral daily dose ranges from 5 mg to 1000 mg. For convenience, the compounds of the present invention can be administered in a unit dosage form. If desired, multiple doses of the standard dosage form may be used per day to increase the total daily dosage. A unit dosage form, for example, may be a tablet or capsule containing about 0.1, 0.5, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65 , 70, 75, 80, 85, 90, 95, 100, 125, 150, 175, 200, 250, 300, 500 or 1000 mg of a compound of the present invention. The total daily dose may be administered as a single dose or in divided doses and may, at the discretion of the physician, be outside the typical ranges specified herein.

For administration to human patients, the daily dose of the compounds of the present invention may range from 1 mg to 2000 mg, depending, of course, on the route and frequency of administration, the disease state, and the age and condition of the patient, etc. As another example, the daily infusion dose ranges from 5 mg to 1000 mg. The total daily dose may be administered as a single dose or in divided doses and may, at the discretion of the physician, be outside the typical ranges specified herein.

In accordance with the treatment methods of the invention, a compound of the present invention or a combination of a compound of the present invention and at least one additional drug (referred to herein as a “combination”) is administered to a subject in need of such treatment, preferably in the form of a pharmaceutical composition. In the combination aspect of the invention, a compound of the present invention and at least one other drug (eg, another anti-cachexia or anorexia drug) can be administered either separately or in a pharmaceutical composition comprising both agents. It is generally preferred that such administration be oral.

When a combination of a compound of the present invention and at least one other drug is administered together, such administration may be sequential in time or simultaneous. In some embodiments, simultaneous administration of drug combinations is used. For separate or sequential administration, the compound of the present invention and the additional drug may be administered in any order, and each may be administered at an independent frequency or dosage regimen. In some embodiments, such administration may be oral. In some embodiments, such administration may be oral and simultaneous. When a compound of the present invention and an additional drug are administered sequentially, each may be administered by the same or different routes.

In accordance with the methods of the invention, the compound of the present invention or combination can be administered in the form of a pharmaceutical composition. Accordingly, a compound of the present invention or a combination can be administered to a patient individually or together in any conventional dosage form for oral, rectal, transdermal, parenteral (e.g., intravenous, intramuscular, or subcutaneous), intracisternal, intravaginal, intraperitoneal, topical (e.g., powder, ointment, cream, spray or lotion), buccal or nasal (eg spray, drops or inhalant) administration.

The compounds of the invention, or combinations thereof, can be administered alone or in admixture with one or more suitable pharmaceutical excipients, adjuvants, diluents or carriers known in the art and selected taking into account the intended route of administration and standard pharmaceutical practice. A compound of the invention or combination may be formulated into immediate, delayed, modified, extended, pulsed or controlled release dosage forms depending on the desired route of administration and the specific release profile commensurate with therapeutic needs.

The pharmaceutical composition includes a compound of the invention or combination in an amount typically ranging from about 1% to about 75%, 80%, 85%, 90%, or even 95% (by weight) of the composition, typically ranging from about 1% , 2% or 3% to about 50%, 60% or 70%, more often in the range from about 1%, 2% or 3% to less than 50%, such as about 25%, 30% or 35%.

Methods for preparing various pharmaceutical compositions containing a specific amount of active compound are known to those skilled in the art. For example, see Remington, J.P., The Science and Practice of Pharmacy, Lippincott Williams and Wilkins, Baltimore, Md. 20th ed., 2000.

Compositions suitable for parenteral injection generally include pharmaceutically acceptable sterile aqueous or non-aqueous solutions, dispersions, suspensions or emulsions and sterile powders for reconstitution into sterile injectable solutions or dispersions. Examples of suitable aqueous and non-aqueous carriers or diluents (including solvents and fillers) include water, ethanol, polyols (propylene glycol, polyethylene glycol, glycerin, etc.), suitable mixtures thereof, triglycerides including vegetable oils such as olive oil, and injectable organic esters such as ethyl oleate. The preferred carrier is Miglyol.RTM, a proprietary ester of caprylic/capric acid with glycerin or propylene glycol (e.g., Miglyol.RTM. 812, Miglyol.RTM. 829, Miglyol.RTM. 840), available from Condea Vista Co., Cranford, N.J. Proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by maintaining the required particle size in the case of dispersions, and by the use of surfactants.

These parenteral compositions may also contain excipients such as preservatives, wetting, emulsifying and dispersing agents. Contamination of compositions by microorganisms can be prevented by the use of various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, etc. It may also be desirable to include isotonic agents, for example, sugars, sodium chloride and the like. Prolonged absorption of injectable pharmaceutical compositions can be achieved using agents capable of delaying absorption, for example, aluminum monostearate and gelatin.

Solid dosage forms for oral administration include capsules, tablets, chewable tablets, lozenges, pills, powders and multiparticulate preparations (granules). In such solid dosage forms, a compound of the present invention or a combination thereof is mixed with at least one inert excipient, diluent or carrier. Suitable excipients, diluents or carriers include substances such as sodium citrate or dicalcium phosphate and/or (a) one or more fillers or bulking agents (for example, microcrystalline cellulose (available as Avicel TM from FMC Corp.), starches, lactose, sucrose, mannitol, silicic acid, xylitol, sorbitol, dextrose, calcium hydrogen phosphate, dextrin, alpha-cyclodextrin, beta-cyclodextrin, polyethylene glycol, medium chain fatty acids, titanium oxide, magnesium oxide, aluminum oxide, etc.); (b) one or more binders (for example, carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, gelatin, gum arabic, ethylcellulose, polyvinyl alcohol, pullulan, pregelatinized starch, agar, tragacanth, alginates, gelatin, polyvinylpyrrolidone, sucrose, acacia, etc.); P.); (c) one or more humectants (eg, glycerin, etc.); (d) one or more disintegrants (e.g., agar agar, calcium carbonate, potato or cassava starch, alginic acid, certain complex silicates, sodium carbonate, sodium lauryl sulfate, sodium starch glycolate (available as Explotab™ from Edward Mendell Co.), cross-linked polyvinylpyrrolidone, croscarmellose sodium type A (available as Ac-di-sol™), potassium polyacryline (ion exchange resin), etc.); (f) one or more dissolution retarders (eg, paraffin, etc.); (f) one or more absorption accelerators (eg, quaternary ammonium compounds, etc.); (e) one or more wetting agents (eg, cetyl alcohol, glycerol monostearate, etc.); (h) one or more adsorbents (eg kaolin, bentonite, etc.); and/or one or more lubricants (for example, talc, calcium stearate, magnesium stearate, stearic acid, polyoxyl stearate, cetanol, hydrogenated castor oil, sucrose fatty acid esters, dimethylpolysiloxane, microcrystalline wax, yellow beeswax, white beeswax, solid polyethylene glycols, sodium lauryl sulfate, etc.). In the case of capsules and tablets, dosage forms may also contain buffering agents.

Solid compositions of a similar type can also be used as fillers in soft or hard gelatin capsules using excipients such as lactose or milk sugar, as well as high molecular weight polyethylene glycols and the like.

Solid dosage forms, such as tablets, dragees, capsules and granules, can be prepared with coatings and shells, such as enteric coatings and others well known in the art. They may also contain opacifying agents and may also be formulated such that they can release a compound of the present invention and/or additional drug in a sustained manner. Examples of potting compositions that can be used are polymeric substances and waxes. The drug may also be in microencapsulated form, optionally with one or more of the above excipients.

In the case of tablets, the active ingredient will typically comprise less than 50% (by weight) of the composition, such as less than about 10%, such as 5% or 2.5% by weight. The predominant part of the composition consists of fillers, diluents, disintegrants, lubricants and, optionally, flavoring agents. Mixtures of such excipients are well known in the art. Often, fillers/diluents include mixtures of two or more of the following: microcrystalline cellulose, mannitol, lactose (all types), starch and dicalcium phosphate. The filler/diluent mixtures typically constitute less than 98% of the composition and preferably less than 95%, for example 93.5%. Preferred disintegrants include Ac-di-sol™, Explotab™, starch and sodium lauryl sulfate. Disintegrant, if present, typically constitutes less than 10% of the composition or less than 5%, such as about 3%. The preferred lubricant is magnesium stearate. The lubricant, if present, typically constitutes less than 5% of the composition or less than 3%, such as about 1%.

Tablets can be produced by standard tableting processes, for example, direct compression or wet, dry or melt granulation, melt solidification and extrusion. Tablet cores may be mono- or multi-layer and may have appropriate coatings known in the art.

Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups and elixirs. In addition to the compound of the present invention or combination, the liquid dosage form may contain inert diluents commonly used in the art, such as water or other solvents, solubilizing agents and emulsifiers, such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, dimethylformamide, oils (for example, cottonseed oil, peanut oil, corn germ oil, olive oil, castor oil, sesame oil, etc.), Miglyol.RTM. (available from CONDEA Vista Co., Cranford, N.J.), glycerin, tetrahydrofurfuryl alcohol, polyethylene glycols and sorbitan fatty acid esters or mixtures thereof, and the like.

In addition to such inert diluents, the composition may also include excipients such as wetting agents, emulsifiers and suspending agents, sweeteners, flavoring agents and flavoring agents.

Oral liquid forms of the compounds or combinations of the invention include solutions in which the active compound is completely dissolved. Examples of solvents include all known pharmaceutical solvents suitable for oral administration, in particular those in which the compounds of the invention exhibit good solubility, for example, polyethylene glycol, polypropylene glycol, edible oils and systems based on glyceryl and glyceride. Glyceryl and glyceride based systems may include, for example, the following branded products (and corresponding generic products): Captex.TM. 355 EP (glyceryl tricaprylate/caprate, from Abitec, Columbus Ohio), Crodamol.TM. (medium chain triglyceride, from Croda, Cowick Hall, UK) or Labrafac.TM. CC (medium chain trigliides from Gattefosse), Captex.TM. 500P (glyceryl triacetate, i.e. triacetin, from Abitec), Capmnl.TM. MCM (medium chain mono- and diglycerides from Abitec), Migyol.TM. 812 (caprylic/capric triglyceride, from Condea, Cranford NJ), Migyol.TM. 829 (caprylic/capric/succinic triglyceride from Condea), Migyol.TM. 840 (propylene glycol dicaprylate/dicaprate, from Condea), Labrafil.TM. M1944CS (oleoylmacrogol-6 glycerides, from Gattefosse), Peceol.TM. (glyceryl monooleate, from Gattefosse) and Maisine.TM. 35-1 (glyceryl monooleate, from Gattefosse). Of particular interest are medium chain triglyceride oils ( _C8 to _C10 ). These solvents often form the predominant part of the composition, i.e. greater than about 50%, typically greater than about 80%, such as about 95% or 99%. Adjuvants and additives may also be included in solvent formulations, primarily as taste-masking, palatability and flavoring agents, antioxidants, stabilizers, texture and viscosity modifiers, and solubilizers.

Suspensions, in addition to the compound of the present invention or combination, may also include carriers such as suspending agents, for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar and tragacanth, or mixtures these substances, etc.

Compositions for rectal or vaginal administration preferably include suppositories, which can be prepared by mixing a compound of the present invention or combination with suitable non-irritating excipients or carriers, such as cocoa butter, polyethylene glycol or suppository wax, which are solid at normal room temperature but liquid at body temperature and therefore melt in the rectum or vaginal cavity, thereby releasing the active component(s).

Dosage forms for topical administration of the compounds of the present invention or combinations thereof include ointments, creams, lotions, powders and sprays. The drugs are mixed with a pharmaceutically acceptable excipient, diluent or carrier and any preservatives, buffers or propellants that may be required.

Some of the compounds of the present invention may be poorly soluble in water, for example, less than about 1 μg/ml. Therefore, liquid formulations in solubilizing non-aqueous solvents, such as the medium chain triglyceride oils discussed above, are the preferred dosage form for these compounds.

Solid amorphous dispersions, including dispersions formed by spray drying processes, are also the preferred dosage form for the poorly soluble compounds of the invention. By "solid amorphous dispersion" is meant a solid in which at least a portion of the poorly soluble compound is in amorphous form and dispersed in a water-soluble polymer. By “amorphous” we mean that the poorly soluble compound is not crystalline. By "crystalline" we mean that the compound exhibits long-range order in three dimensions, with at least 100 repeating units in each dimension. Thus, the term "amorphous" is intended to include not only matter that is essentially without order, but also matter that may have some small degree of order, but order in less than three dimensions and/or only over short distances. The amorphous material can be characterized by methods known in the art, such as crystallographic powder X-ray diffraction (PXRD), solid-state NMR, or thermal methods such as differential scanning calorimetry (DSC).

Preferably, at least a majority (ie, at least about 60% by weight) of the poorly soluble compound in the solid amorphous dispersion is amorphous. The compound may exist in a solid amorphous dispersion in relatively pure amorphous domains or regions, as a solid solution of the compound homogeneously distributed throughout the polymer, or in any combination of these states or those states in between. The solid amorphous dispersion is preferably substantially homogeneous, such that the amorphous compound is dispersed as uniformly as possible within the polymer. The term "substantially homogeneous" means that the proportion of the compound that is present in the relatively pure amorphous domains or regions in the solid amorphous dispersion is relatively small, on the order of less than 20% by weight. and preferably less than 10% of the mass. of the total amount of the drug.

Water-soluble polymers suitable for use in solid amorphous dispersions must be inert in the sense that they do not undergo adverse chemical reactions with the poorly soluble compound, are pharmaceutically acceptable, and have at least some solubility in aqueous solution at physiologically relevant pH values ( for example 1-8). The polymer may be neutral or ionizable and must have a water solubility of at least 0.1 mg/ml over at least part of the pH range 1-8.

Water-soluble polymers suitable for use in the present invention may be cellulosic or non-cellulosic. Polymers can be neutral or ionizable in aqueous solution. Of these, ionizable and cellulose polymers are preferred, with ionizable cellulose polymers being more preferred.

Examples of water-soluble polymers include hydroxypropyl methylcellulose acetate succinate (HPMCAS), hydroxypropyl methylcellulose (HPMC), hydroxypropyl methylcellulose phthalate (HPMCP), carboxymethylethylcellulose (CMEC), cellulose acetate phthalate (CAP), cellulose acetate trimellitate (CAT), polyvinylpyrrolidone (PVP), hydroxypropylcellulose (HPC) , methylcellulose (MC), block copolymers of ethylene oxide and propylene oxide (PEO/PPO, also known as poloxamers) and mixtures thereof. Particularly preferred polymers include HPMCAS, HPMC, HPMCP, CMEC, CAP, CAT, PVP, poloxamers, and mixtures thereof. HPMCAS is the most preferred. See European Patent Application Publication No. 0901786 A2, the disclosure of which is incorporated herein by reference.

Solid amorphous dispersions can be prepared by any method that provides solid amorphous dispersions in which at least a large portion (at least 60%) of the poorly soluble compound is in an amorphous state. Such methods include mechanical, thermal and solvent methods. Examples of mechanical methods include grinding and extrusion; melting methods, including high temperature melting, solvent modified melting and melt solidification methods; and solvent-based methods, including solventless deposition, spray coating, and spray drying. See, for example, the following US patents, the corresponding disclosures of which are incorporated herein by reference: Nos. 5,456,923 and 5,939,099, which describe the preparation of dispersions by extrusion methods; 5340591 and 4673564, which describe the preparation of dispersions by grinding methods; and Nos. 5707646 and 4894235, which describe the formation of dispersions by melt solidification methods. In a preferred method, the solid amorphous dispersion is obtained by spray drying as described in European Patent Application Publication No. 0901786 A2. In this method, the compound and polymer are dissolved in a solvent such as acetone or methanol, after which the solvent is quickly removed from the solution by spray drying to form a solid amorphous dispersion. Solid amorphous dispersions can be prepared in such a way that they contain up to about 99% of the mass. compounds, for example, 1% wt., 5% wt., 10% wt., 25% wt., 50% wt., 75% wt., 95% wt. or 98% wt., as desired.

The solid dispersion can be used as such as a dosage form, or it can serve as a manufacturing use product (MUP) for the preparation of other dosage forms such as capsules, tablets, solutions or suspensions. An example of an aqueous suspension is an aqueous suspension of a spray-dried 1:1 (w/w) compound/HPMCAS-HF dispersion containing 2.5 mg/ml compound in 2% polysorbate-80. Solid dispersions for use in tablets or capsules are usually mixed with other excipients or adjuvants typically present in such dosage forms. For example, an exemplary capsule fill contains 2:1 (w/w) compound/HPMCAS-MF spray-dried dispersion (60%), lactose (fast flow) (15%), microcrystalline cellulose (e.g., Avicel.sup. (RO -102) (15.8%), sodium starch (7%), sodium lauryl sulfate (2%) and magnesium stearate (1%).

HPMCAS polymers are available in low, medium and high purity as Aqoa(R)-LF, Aqoat(R)-MF and Aqoat(R)-HF, respectively, from Shin-Etsu Chemical Co., LTD, Tokyo, Japan. Generally, the higher MF and HF grades are preferred.

Conveniently, the compound of the present invention (or combination) can be delivered through drinking water such that a therapeutic dose of the compound is ingested with the daily water supply. The compound can be added directly to drinking water, preferably in the form of a liquid water-soluble concentrate (such as an aqueous solution of a water-soluble salt).

These compounds can also be administered to non-human animals, for example, for the indications detailed above. The exact dosage of each active ingredient administered will vary depending on a number of factors, including, but not limited to, the type of animal and type of disease condition, the age of the animal and the route(s) of administration.

Drugs used in combination with compounds of formula I or their salts are used in a dose that is effective for the indication being treated. Such doses can be determined by standard assays such as those mentioned above and presented herein. The combination agents can be administered simultaneously or sequentially in any order.

These dosages are based on an average human subject having a body weight of approximately 60 to 70 kg. Your healthcare provider will be able to easily determine doses for subjects whose body weight is outside this range, such as infants and the elderly.

Dosing regimens can be adjusted to provide the optimal desired response. For example, a single bolus may be administered, multiple divided doses may be administered over time, or the dose may be proportionally decreased or increased according to the therapeutic situation. It is particularly advantageous to formulate parenteral compositions in unit dosage form for ease of administration and uniformity of dosage. Unit dosage form, as used herein, refers to physically discrete units suitable as unitary dosages for the mammal to be treated; each unit contains a predetermined amount of active compound calculated to produce the desired therapeutic effect, in combination with the required pharmaceutical carrier. The specification for unit dosage forms of the invention is dictated by and directly depends on (a) the unique characteristics of the chemotherapeutic agent and the particular therapeutic or prophylactic effect to be achieved, and (b) the limitations existing in the art of formulating such active compound for the treatment of sensitivity in individuals.

Thus, those skilled in the art will appreciate, based on the present disclosure, that the dosage and schedule of administration will be adjusted in accordance with methods well known in the art of therapy. That is, the maximum tolerated dose can be easily determined, and the effective amount to provide a detectable therapeutic effect in a patient, as well as the time requirements for administering each agent to provide a detectable therapeutic effect in a patient, can be determined. Accordingly, although this application provides examples of specific dosages and dosage regimens, these examples do not in any way limit the dosages and dosage regimens that may be provided to a patient in the practice of the present invention.

It should be noted that dosages may vary depending on the type and severity of the condition being alleviated and may include single or multiple doses. In addition, it should be understood that for any particular subject, specific dosage regimens must be adjusted over time in accordance with the individual needs and professional judgment of the person administering or supervising the administration of the compositions, and that the dosage ranges set forth herein are illustrative only. and are not intended to limit the scope or application of the claimed composition. For example, dosages may be adjusted based on pharmacokinetic or pharmacodynamic parameters, which may include clinical effects such as toxic effects and/or laboratory parameters. Thus, the present invention covers dose escalation for an individual patient as determined by one skilled in the art. Determination of suitable dosages and schedules of administration of a chemotherapeutic agent is well known in the relevant art, and those skilled in the art will understand that they are covered when they read the disclosure presented in this application.

The present invention also includes the use of a compound of formula I or a pharmaceutically acceptable salt thereof as a medicament (such as a unit strength tablet or unit strength capsule). In another embodiment, the present invention includes the use of a compound of Formula I or a pharmaceutically acceptable salt thereof for the preparation of a medicament (such as a unit strength tablet or capsule) for the treatment of one or more of the conditions defined in the sections described above discussing methods of treatment .

The pharmaceutical composition of the present invention may be prepared, packaged, or sold in bulk, as a single unit dose or as a plurality of unit doses. As used herein, the term “unit dose” is a discrete amount of a pharmaceutical composition containing a predetermined amount of the active ingredient. The amount of active ingredient is typically equal to the dose of active ingredient to be administered to the subject, or a suitable portion of such dose, such as, for example, one-half or one-third of such dose.

These agents and compounds of the invention can be combined with pharmaceutically acceptable carriers such as saline, Ringer's solution, dextrose solution and the like. The specific schedule of administration, i.e. dosage, dosage intervals, and repetition will depend on the individual subject and the subject's medical history.

Acceptable carriers, excipients or stabilizers are non-toxic to recipients at the dosages and concentrations used and may include buffers such as phosphate, citrate and other organic acids; salts such as sodium chloride; antioxidants including ascorbic acid and methionine; preservatives (such as octadecyldimethylbenzylammonium chloride, hexamethonium chloride, benzalkonium chloride, benzethonium chloride, phenol, butyl or benzyl alcohol, alkylparabens such as methyl or propylparaben, catechol, resorcinol, cyclohexanol, 3-pentanol and m-cresol); low molecular weight (less than about 10 residues) polypeptides; proteins such as serum albumin, gelatin or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine or lysine; monosaccharides, disaccharides and other carbohydrates, including glucose, mannose or dextrins; chelating agents such as EDTA; sugars such as sucrose, mannitol, trehalose or sorbitol; salt-forming counterions such as sodium; metal complexes (eg Zn-protein complexes); and/or non-ionic surfactants such as TWEENT™, PLURONICS™ or polyethylene glycol (PEG).

Liposomes containing these agents and/or compounds of the invention are prepared by methods known in the art, such as those described in US Pat. Nos. 4,485,045 and 4,544,545. Extended circulation time liposomes are disclosed in US Pat. No. 5,013,556. Particularly useful liposomes can be prepared by reverse phase evaporation with a lipid composition including phosphatidylcholine, cholesterol and PEG-derivatized phosphatidylethanolamine (PEG-PE). Liposomes are extruded through filters of specific pore sizes to obtain liposomes of the desired diameter.

These agents and/or compounds of the invention can also be enclosed in microcapsules obtained, for example, by coacervation or interfacial polymerization methods, for example, hydroxymethylcellulose or gelatin microcapsules and poly(methyl methacrylate) microcapsules, respectively, in colloidal drug delivery systems (for example, liposomes , albumin microspheres, microemulsions, nanoparticles and nanocapsules) or in macroemulsions. Such methods are disclosed in Remington, The Science and Practice of Pharmacy, 20th Ed., Mack Publishing (2000).

Long-acting medications can be used. Suitable examples of sustained release formulations include semi-permeable matrices of solid hydrophobic polymers containing a compound of the invention, the matrices being in the form of molded articles such as films or microcapsules. Examples of sustained release matrices include polyesters, hydrogels [e.g., poly(2-hydroxyethyl methacrylate) or poly(vinyl alcohol)], polylactides (US Pat. No. 3,773,919), copolymers of L-glutamic acid and ethyl-L-glutamate, non-degradable ethylene vinyl acetate, degradable copolymers of lactic acid and glycolic acid such as those used in LUPRON DEPOT™ (injectable microspheres consisting of copolymer of lactic acid and glycolic acid and leuprolide acetate), sucrose acetate isobutyrate and poly-D-(-)-3-hydroxybutyric acid.

Compositions used for intravenous administration must be sterile. This is easily accomplished, for example, by filtration through sterile filtration membranes. The compounds of the invention are typically placed in a container with a sterile entry port, such as an intravenous solution bag or vial with a stopper pierced by a hypodermic needle.

Suitable emulsions can be prepared using commercially available fat emulsions such as Intralipid™, Liposyn™, Infonutrol™, Lipofundin™ and Lipiphysan™. The active ingredient can be dissolved in a premixed emulsion composition, or alternatively, it can be dissolved in an oil (eg, soybean oil, safflower oil, cottonseed oil, sesame oil, corn oil or almond oil) and the emulsion is prepared by mixing with a phospholipid ( for example, egg phospholipids, soy phospholipids or soy lecithin) and water. It should be understood that other ingredients, such as glycerin or glucose, may be added to adjust the tonicity of the emulsion. Suitable emulsions typically contain up to 20% oil, for example 5 to 20%. The fat emulsion may comprise fat droplets ranging in size from 0.1 to 1.0 microns, in particular from 0.1 to 0.5 microns, and have a pH in the range from 5.5 to 8.0.

Emulsion compositions can be prepared by mixing a compound of the invention with Intralipid™ or its components (soybean oil, egg phospholipids, glycerin and water).

Compositions for inhalation or insufflation include solutions and suspensions in pharmaceutically acceptable aqueous or organic solvents or mixtures thereof, as well as powders. Liquid or solid compositions may contain suitable pharmaceutically acceptable excipients as described above. In some embodiments, the compositions are administered orally or nasally for local or systemic effects. The compositions in preferably sterile pharmaceutically acceptable solvents can be nebulized using gases. Nebulized solutions can be inhaled directly from the nebulizer, or the nebulizer can be attached to a face mask, tent, or intermittent positive pressure breathing apparatus. Solutions, suspensions or powder compositions can be administered, preferably orally or nasally, from devices that deliver the composition in an appropriate manner.

The compounds of the present invention may be formulated for oral, buccal, intranasal, parenteral (eg, intravenous, intramuscular or subcutaneous) or rectal administration, or in a form suitable for administration by inhalation. The compounds of the invention may also be formulated for sustained delivery.

Methods for preparing various pharmaceutical compositions with specific amounts of active ingredient are known or will become apparent to those skilled in the art in light of the present disclosure. For examples of methods for preparing pharmaceutical compositions, see Remington, The Science and Practice of Pharmacy, 20th Edition (Lippincott Williams & Wilkins, 2000).

The pharmaceutical compositions of the invention may contain from 0.1% to 95% of the compound(s) of the invention, preferably from 1% to 70%. In any case, the composition administered will contain the compound(s) of the invention in an amount effective to treat the disease/condition of the subject being treated.

Since the present invention has an aspect that relates to the treatment of diseases/conditions described herein with a combination of active ingredients that can be administered separately, the invention also relates to the combination of individual pharmaceutical compositions in the form of a kit. The kit includes two separate pharmaceutical compositions: a compound of Formula I, or a pharmaceutically acceptable salt thereof, or a prodrug thereof, or a salt of such a compound or prodrug, and a second compound as described above. The kit includes means for containing individual compositions, such as a container, a divided bottle or a divided foil pouch. Typically, the kit includes instructions for using the individual components. The kit form is particularly preferred when the individual components are preferably administered in different dosage forms (eg, orally and parenterally), administered at different intervals between administrations, or when titration of the individual components of the combination is desired at the discretion of the attending physician.

An example of such a set is the so-called blister packaging. Blister packs are well known in the packaging industry and are widely used for packaging standard dosage forms (tablets, capsules, etc.). Blister packaging usually consists of a sheet of relatively rigid material covered with foil, preferably clear plastic. During the packaging process, indentations are formed in the plastic film. The recesses are the size and shape of the tablets or capsules being packaged. The tablets or capsules are then placed into the recesses and a sheet of relatively rigid material is sealed with plastic foil on the face of the foil opposite the direction in which the recesses were formed. As a result, the tablets or capsules are sealed in the recesses between the plastic film and the sheet. Preferably, the strength of the sheet is such that the tablets or capsules can be removed from the blister pack by pressing the indentations with one's hand, thereby creating a hole in the sheet at the indentation. The tablet or capsule can then be removed through the designated opening.

It may be desirable to provide a reminder in the kit, for example in the form of numbers next to the tablets or capsules, the numbers corresponding to specific days of the dosing schedule when the tablets or capsules so indicated should be taken. Another example of such a reminder is a calendar printed on a card, for example, as follows: “First week, Monday, Tuesday, etc... Second week, Monday, Tuesday... etc.” Other options for reminders will be very obvious. A "daily dose" may be one tablet or capsule, or several tablets or capsules taken on a given day. In addition, a daily dose of a compound of the present invention may consist of one tablet or capsule, while a daily dose of a second compound may consist of several tablets or capsules, and vice versa. The memo should reflect this.

In another specific embodiment of the invention, a dispenser is provided for dispensing daily doses one at a time in the order of their intended use. Preferably, the dispenser is equipped with a memory device to further facilitate compliance. An example of such a storage device is a mechanical counter, which shows the number of measured daily doses. Another example of such a storage device is a battery-powered microchip memory combined with a liquid crystal reader or reminder tone that, for example, reads the date of the last daily dose and/or reminds the subject when the next dose is due.

In addition, while the present invention has an aspect that relates to the treatment of diseases/conditions described herein with a combination of active ingredients that can be administered together, the invention also relates to the combination of separate pharmaceutical compositions in a single dosage form, such as (but not limited to) single tablet or capsule, bilayer or multilayer tablet or capsule, or through the use of segregated components or partitions in the tablet or capsule.

The active ingredient may be delivered as a solution in an aqueous or non-aqueous vehicle, with or without the use of additional solvents, cosolvents, excipients or complexing agents selected from pharmaceutically acceptable diluents, excipients, solvents or carriers.

The active ingredient may be formulated as a solid dispersion or as a self-emulsifying drug delivery system (SEDDS) with pharmaceutically acceptable excipients.

The active ingredient may be formulated as an immediate or controlled (eg, delayed, sustained or extended) release tablet or capsule. Alternatively, the active ingredient may be delivered as the active ingredient alone in a capsule shell without additional excipients.

EXAMPLES

The synthesis of various compounds of the present invention is illustrated below. Additional compounds within the scope of the present invention can be prepared using the methods illustrated in these Examples, either alone or in combination with methods well known in the art. All starting materials in these Preparations and Examples are either commercially available or can be prepared by methods known in the art or described herein.

Reactions were carried out in air or, when oxygen- or moisture-sensitive reagents or intermediates were used, in an inert atmosphere (nitrogen or argon). When necessary, the reactors were dried under dynamic vacuum using a heat gun and anhydrous solvents were used (Sure-Seal™ products from Aldrich Chemical Company, Milwaukee, Wisconsin, or DriSolv™ products from EMD Chemicals, Gibbstown, NJ). In some cases, commercial solvents were passed through columns packed with 4Å molecular sieves until the following quality control standards for water were achieved: a) <100 ppm for dichloromethane, toluene, N,N-dimethylformamide, and tetrahydrofuran; b) <180 ppm for methanol, ethanol, 1,4-dioxane and diisopropylamine. For very sensitive reactions, solvents were further treated with sodium metal, calcium hydride, or molecular sieves and distilled immediately before use. Other commercial solvents and reagents were used without further purification. For synthesis methods referring to procedures in other Examples or Methods, reaction conditions (reaction time and temperature) may vary. Products were typically dried under vacuum before being used in further reactions or biological tests.

When indicated, reaction mixtures were heated under microwave conditions using a Biotage Initiator or Personal Chemistry Emrys Optimizer microwave device. The reaction progress was monitored by thin layer chromatography (TLC), liquid chromatography/mass spectrometry (LC-MS), high performance liquid chromatography (HPLC) and/or gas chromatography/mass spectrometry (GC-MS). TLC was carried out on silica gel plates pre-coated with a fluorescent indicator (excitation wavelength 254 nm) and visualized under UV light and/or by staining with iodine, potassium permanganate, cobalt (II) chloride, phosphomolybdic acid and/or cerium molybdate. ammonium LC-MS data were acquired on an Agilent 1100 series instrument with a Leap Technologies autosampler, Gemini C18 columns, acetonitrile/water gradients, and modifiers such as trifluoroacetic acid, formic acid, or ammonium hydroxide. The column eluent was analyzed using a Waters ZQ mass spectrometer scanning in both positive and negative ionization modes over a range of 100 to 1200 Da. Other similar devices were also used. HPLC data were typically acquired on an Agilent 1100 series instrument using the specified columns, acetonitrile/water gradients, and trifluoroacetic acid or ammonium hydroxide as modifiers. GCMS data were acquired using a Hewlett Packard 6890 oven with an HP 6890 injector, HP-1 column (12 m × 0.2 mm × 0.33 μm), and helium carrier gas. The sample was analyzed on an HP 5973 mass selective detector scanning from 50 to 550 Da using electron ionization. Purification was performed by medium-pressure liquid chromatography (MPLC) using an Isco CombiFlash Companion, AnaLogix IntelliFlash 280, Biotage SP1, or Biotage Isolera One and prepackaged Isco RediSep or Biotage Snap silica gel cartridges. Chiral purification was performed by chiral supercritical fluid chromatography (SFC), typically using Berger or Thar apparatus; columns such as ChiralPAK-AD, -AS, -IC, Chiralcel-OD or -OJ columns; and mixtures of CO ₂ with methanol, ethanol, 2-propanol or acetonitrile, used as such or modified using trifluoroacetic acid or propan-2-amine. UV detection was used to trigger fraction collection. For synthesis methods, reference to procedures in other Examples or Purification Methods may vary: in general, solvents and solvent ratios used for eluents/gradients were selected to provide appropriate R _f values or retention times.

Mass spectrometry data were obtained from LCMS analyses. Mass spectrometry (MS) was performed by atmospheric pressure chemical ionization (APCI), electrospray ionization (ESI), electron impact ionization (EI), or electron scattering ionization (ES). Proton nuclear magnetic spectroscopy ( ^1H NMR) chemical shifts are reported in ppm downfield from tetramethylsilane and were obtained on Varian, Bruker or Jeol spectrometers at 300, 400, 500 or 600 MHz. Chemical shifts are expressed in parts per million (ppm, δ) relative to the residual peaks of the deuterated solvent (chloroform, 7.26 ppm; CD2HOD, 3.31 ppm; acetonitrile- _d2 , 1.94 ppm). d.; dimethyl sulfoxide-d ₅ , 2.50 ppm; DHO, 4.79 ppm). The peak shapes are described as follows: singlet; d - doublet; t - triplet; sq. - quartet; quint. - quintet; m - multiplet; wide.s - widened singlet; each - apparent. SFC analytical data were typically obtained on a Berger analytical device as described above. Optical rotation data were acquired on a PerkinElmer model 343 polarimeter using a 1 dm cuvette. Microanalyses were performed by Quantitative Technologies Inc. and were within 0.4% of the calculated values.

Unless otherwise stated, chemical reactions were performed at room temperature (about 23 degrees Celsius).

Unless otherwise stated, all reagents were commercially obtained and used without further purification or were prepared using methods known from the literature.

The terms "concentrated", "evaporated" and "concentrated in vacuo" refer to the removal of solvent under reduced pressure on a rotary evaporator with a bath temperature of less than 60°C. The abbreviations "min" and "h" stand for "minutes" and "hours", respectively. The term "TLC" refers to thin layer chromatography, "room temperature or ambient temperature" means a temperature of 18 to 25°C, "GCMS" refers to gas chromatography/mass spectrometry, "LCMS" refers to liquid chromatography/mass spectrometry, "UHPLC" refers to ultra-performance liquid chromatography, and "HPLC" refers to high-performance liquid chromatography, "SFC" refers to supercritical fluid chromatography.

Hydrogenation can be carried out in a Parr shaker under pressure of hydrogen gas or in a Thales-nano H-Cube flow hydrogenation reactor with full hydrogen utilization and a flow rate of 1-2 ml/min at a given temperature.

HPLC, UHPLC, LCMS, GCMS, and SFC retention times were measured using the methods specified in the procedures.

In some examples, chiral resolution was performed to separate enantiomers or diastereomers of certain compounds of the invention (in some examples, the separated enantiomers are designated ENT-1 and ENT-2 according to their elution order; similarly, the separated diastereomers are designated DIAST-1 and DIAST- 2 according to their elution order). In some examples, the optical rotation of the enantiomer was measured using a polarimeter. According to its observed rotation data (or its specific rotation data), the enantiomer with clockwise rotation was designated as the (+)-enantiomer, and the enantiomer with counterclockwise rotation was designated as the (-)-enantiomer. Racemic compounds are indicated by either the absence of stereochemistry shown or described or the presence of (+/-) near the structure; in this latter case, the indicated stereochemistry represents only one of the two enantiomers constituting the racemic mixture.

The compounds and intermediates described below were named using the naming convention provided by ACD/ChemSketch 2017.2.1, File Version C40H41, Build 99535 (Advanced Chemistry Development, Inc., Toronto, Ontario, Canada). The naming convention provided in ACD/ChemSketch 2017.2.1 is well known to those skilled in the art, and the naming convention provided in ACD/ChemSketch 2017.2.1 is believed to be generally consistent with IUPAC (International Union for Pure and Applied Chemistry) recommendations ) according to the nomenclature of organic chemistry and the rules of the CAS index.

The ¹ H NMR spectra of many of the compounds in this application indicate a mixture of rotamers due to the presence of amide and/or carbamate functionality, and they have been tabulated to reflect the presence of more than one rotamer.

RECEIVING

Preparations P1 to P33 describe the preparation of certain starting materials or intermediates used to prepare certain compounds of the invention.

Receiving P1

2-(5-Chloro-2-methoxypyridin-4-yl)propanoic acid (P1)

Step 1. Synthesis of methyl (5-Chloro-2-methoxypyridin-4-yl) acetate (C1).

A solution of lithium diisopropylamide in tetrahydrofuran (2 M; 1.9 L, 3.8 mol) was added dropwise to a -30°C solution of 5-chloro-2-methoxy-4-methylpyridine (197 g, 1.25 mol) in tetrahydrofuran (1.4 l). After stirring the reaction mixture at -30°C for 1 hour, dimethyl carbonate (338 g, 3.75 mol) was added dropwise; upon completion of addition, the reaction mixture was heated to 25°C and stirred for 1 hour. The mixture was then poured into hydrochloric acid (0.5 M, 7 L, 3.5 mol) and extracted with ethyl acetate (2 x 1.5 L); the combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. Purification by chromatography on silica gel (gradient: 0% to 20% ethyl acetate in petroleum ether) gave C1 as a yellow oil. Yield: 203 g, 0.941 mol, 75%. LCMS m/z 216.1 (observed chlorine isotope pattern) [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ) δ 8.10 (s, 1H), 6.82 (s, 1H), 3.90 (s, 3H), 3.79 (s, 2H), 3 .71 (s, 3H).

Stage 2. Synthesis of methyl 2-(5-chloro-2-methoxypyridin-4-yl)propanoate (C2).

To a -78°C solution of C1 (175 g, 0.812 mol) in tetrahydrofuran (1.2 L) was added a solution of sodium bis(trimethylsilyl)amide in tetrahydrofuran (2 M; 455 ml, 0.910 mol) dropwise. The reaction mixture was stirred at -78°C for 1 hour, then a solution of iodomethane (172.6 g, 1.216 mol) in tetrahydrofuran (100 ml) was added dropwise at -78°C and stirring was continued at this temperature for 2 hours. The reaction mixture was then poured into saturated aqueous ammonium chloride (500 ml) and extracted with ethyl acetate (2 x 100 ml); the combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo to give C2 as a brown oil. NMR and LCMS analysis indicated that the substance was contaminated with some dimethylated by-product methyl 2-(5-chloro-2-methoxypyridin-4-yl)-2-methylpropanoate. Yield: 136 g, ≤0.592 mol, ≤73%. LCMS m/z 230.1 (observed chlorine isotope pattern) [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ), product peak only: δ 8.10 (s, 1H), 6.76 (s, 1H), 4.10 (q, J=7.2 Hz, 1H), 3.89 (s, 3H), 3.69 (s, 3H), 1.48 (d, J=7.2 Hz, 3H).

Stage 3. Synthesis of 2-(5-chloro-2-methoxypyridin-4-yl)propanoic acid (P1).

To a 25°C solution of C2 (168 g, 0.732 mol) in tetrahydrofuran (1 L) was added dropwise a solution of lithium hydroxide monohydrate (61.4 g, 0.146 mol) in water (300 ml) at 25°C. The mixture was stirred for 2 hours, then concentrated in vacuo. The aqueous residue was poured into water (500 ml) and washed with tert-butyl methyl ether (2 x 500 ml). The aqueous layer was then adjusted to pH 4 by adding 3 M hydrochloric acid and extracted with ethyl acetate (2 x 500 ml); the combined ethyl acetate layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated under reduced pressure to give P1 as a white solid. Yield: 122 g, 0.566 mol, 77%. LCMS m/z 216.1 (observed chlorine isotope pattern) [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.10 (s, 1H), 6.79 (s, 1H), 4.06 (q.v., J=7.1 Hz, 1H), 3, 89 (s, 3H), 1.48 (d, J=7.2 Hz, 3H).

Receiving P2 and P3

(2R)-2-(5-Chloro-2-methoxypyridin-4-yl)propanoic acid (P2) and (2S)-2-(5-Chloro-2-methoxypyridin-4-yl)propanoic acid (P3)

Separation of P1 (5.00 g, 23.2 mmol) into its constituent enantiomers was carried out by supercritical fluid chromatography (Column: Chiral Technologies Chiralpak IG, 30 × 250 mm, 5 μm; Mobile phase: 95:5 carbon dioxide/methanol; Flow rate : 80 ml/min; Back pressure: 120 bar). The first eluting enantiomer, an oil that solidified on standing, was indicated as P2, and the second eluting enantiomer as P3.

The indicated absolute stereochemistry was assigned by X-ray determination of the crystal structure of compound 15, which was synthesized using this batch P2 (see below. Example 15, Alternative Step 3).

P2 - Yield: 2.4 g, 11.1 mmol, 48%. ¹ H NMR (400 MHz, chloroform-d) δ 8.13 (s, 1H), 6.75 (s, 1H), 4.12 (q, J=7.2 Hz, 1H), 3.91 (s, 3H), 1.53 (d, J=7.2 Hz, 3H). Retention time: 3.98 minutes (Analytical conditions. Column: Chiral Technologies Chiralpak IG, 4.6 x 250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: methanol; Gradient: 5% B for 1. 00 minutes, then 5% to 60% B for 8 minutes; Flow rate: 3.0 ml/min; Back pressure: 120 bar).

P3 - Yield: 2.4 g, 11.1 mmol, 48%. Retention time: 4.22 minutes (Analytical conditions identical to those used for P2).

Getting P4

Lithium 2-(6-Methoxy-2-methylpyrimidin-4-yl)propanoate (P4)

Step 1. Synthesis of dimethyl(6-methoxy-2-methylpyrimidin-4-yl) (methyl)propanedioate (C3) and methyl 2-(6-methoxy-2-methylpyrimidin-4-yl)propanoate (C4).

Sodium hydride (60% in mineral oil; 1.14 g, 28.5 mmol) was added to a solution of dimethylmethylpropanedioate (5.53 g, 37.8 mmol) in N,N-dimethylformamide (25 ml). After 30 minutes, 4-chloro-6-methoxy-2-methylpyrimidine (3.00 g, 18.9 mmol) was added, then the reaction mixture was heated at 100°C for 16 hours. The mixture was then diluted with water (150 ml) and extracted with ethyl acetate (3 x 50 ml); the combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered, concentrated in vacuo and purified by chromatography on silica gel (gradient: 0% to 10% ethyl acetate in petroleum ether) to give the product (2.60 g) as yellow oils Based on NMR and LCMS analysis, it was believed to be an impurity-containing mixture of C3 and C4, which was directly used in the next step. LCMS m/z 211.1 and 269.2 [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ), characteristic peaks: δ 6.68 (s), 6.60 (s), 3.96 (s), 3.94 (s), 3.81 (sq. ., J=7.2 Hz), 3.75 (s), 3.68 (s), 2.54 (s), 2.52 (s), 1.79 (s), 1.47 (d , J=7.3 Hz).

Stage 2. Synthesis of lithium 2-(6-methoxy-2-methylpyrimidin-4-yl)propanoate (P4).

A solution of C3 and C4 (from the previous step; 2.60 g, ≤18.9 mmol) and lithium hydroxide monohydrate (1.22 g, 29.1 mmol) in a mixture of tetrahydrofuran (45 ml) and water (15 ml) was stirred at 45°C for 3 hours. The reaction mixture was concentrated in vacuo and the residue was lyophilized to give P4 as a white solid. Yield: 2.3 g, 11 mmol, 58% in 2 stages. LCMS m/z 197.1 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 6.66 (s, 1H), 3.94 (s, 3H), 3.61 (q.v., J=7.3 Hz, 1H), 2, 53 (s, 3H), 1.44 (d, J=7.2 Hz, 3H).

Receiving P5

2-[6-(Difluoromethoxy)pyridin-3-yl]propanoic acid (P5)

Step 1. Synthesis of 2-(difluoromethoxy)-5-iodopyridine (C5).

Sodium chloro(difluoro)acetate (4.62 g, 30.3 mmol) and potassium carbonate (5.58 g, 40.4 mmol) were added to a 25°C solution of 5-iodopyridin-2-ol (4.46 g, 20.2 mmol) in N,N-dimethylformamide (100 ml) and the reaction mixture was stirred at 50°C for 16 hours. The mixture was then diluted with water (500 ml) and extracted with ethyl acetate (3 x 100 ml) and the combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 8% ethyl acetate in petroleum ether) gave C5 as an oil. Yield: 2.10 g, 7.75 mmol, 38%. ¹ H NMR (400 MHz, chloroform-d) δ 8.39 (bd, J=2.2 Hz, 1H), 7.97 (dd, J=8.6, 2.3 Hz, 1H), 7.40 (t, J _HF =72.6 Hz, 1H), 6.74 (bd, J=8.6 Hz, 1H).

Step 2. Synthesis of diethyl[6-(difluoromethoxy)pyridin-3-yl]propanedioate (C6).

Mixture of C5 (1.9 g, 7.0 mmol), diethylpropanedioate (1.68 g, 10.5 mmol), copper(I) iodide (133 mg, 0.698 mmol), pyridine-2-carboxylic acid (172 mg, 1.40 mmol) and cesium carbonate (7.42 g, 22.8 mmol) in tetrahydrofuran (50 ml) were stirred at 80°C for 16 hours, then the reaction mixture was diluted with ethyl acetate (100 ml) and washed with aqueous ammonium chloride (100 ml). The aqueous layer was extracted with ethyl acetate (2 x 50 ml) and the combined organic layers were dried over sodium sulfate, filtered and concentrated in vacuo. Purification by chromatography on silica gel (gradient: 0% to 15% ethyl acetate in petroleum ether) gave C6 as a colorless oil (2.4 g). According to ¹ H NMR analysis, this substance contained residual diethyl propanedioate; part of this sample was used directly in the next step. LCMS m/z 304.0 [M+H] ⁺ . ^l H NMR (400 MHz, chloroform-d), product peaks only: δ 8.14 (br.s, 1H), 7.90 (br.d, J=8.4 Hz, 1H), 7.45 ( t, J _HF =72.9 Hz, 1H), 6.92 (d, J=8.4 Hz, 1H), 4.59 (s, 1H), 4.26-4.17 (m, 4H, presumably; partially hidden by residual diethylpropanedioate), 1.31-1.24 (m, 6H, presumably; partially hidden by residual diethylpropanedioate).

Step 3. Synthesis of diethyl[6-(difluoromethoxy)pyridin-3-yl](methyl)propanedioate (C7).

To a solution of C6 (from the previous step; 750 mg, ≤2.2 mmol) in N,N-dimethylformamide (15 ml) was added potassium carbonate (1.03 g, 7.45 mmol). Iodomethane (527 mg, 3.71 mmol) was added dropwise and the reaction mixture was stirred at 25°C for 4 hours. The mixture was then combined with a similar reaction using C6 (250 mg, ≤0.73 mmol), poured into water (200 ml) and extracted with ethyl acetate (2 x 50 ml). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate and concentrated in vacuo; chromatography on silica gel (gradient: 0% to 15% ethyl acetate in petroleum ether) gave C7 as an oil. Combined yield: 738 mg, 2.33 mmol, 80% in 2 steps. LCMS m/z 318.2 [M+H] ⁺ . ¹ H NMR (400 MHz, chloroform-d) δ 8.20 (b.s, 1H), 7.81 (b.d, J=8.7 Hz, 1H), 7.45 (t, J _HF = 72.9 Hz, 1H), 6.90 (d, J=8.7 Hz, 1H), 4.30-4.18 (m, 4H), 1.87 (s, 3H), 1.27 ( t, J=7.1 Hz, 6H).

Step 4. Synthesis of 2-[6-(difluoromethoxy)pyridin-3-yl]propanoic acid (P5).

To a 25°C solution of C7 (738 mg, 2.33 mmol) in tetrahydrofuran (10 ml) was added a solution of lithium hydroxide (279 mg, 11.6 mmol) in water (3 ml). The reaction mixture was stirred at 25°C for 16 hours, then diluted with water (100 ml) and washed with dichloromethane (3 x 50 ml). These organic layers were drained. The aqueous layer was adjusted to pH 5 by adding 5 M hydrochloric acid, then extracted with dichloromethane (3 x 50 ml); the combined organic layers were concentrated in vacuo to give P5 as a solid. Yield: 337 mg, 1.55 mmol, 67%. LCMS m/z 218.1 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.15 (d, J=2.5 Hz, 1H), 7.83 (dd, J=8.5, 2.5 Hz, 1H), 7 .51 (t, J _HF =73.2 Hz, 1H), 6.94 (d, J=8.5 Hz, 1H), 3.78 (sq., J=7.2 Hz, 1H), 1 .49 (d, J=7.2 Hz, 3H).

Getting P6

2-(5-Fluoro-2-methoxypyridin-4-yl)propanoic acid (P6)

Step 1. Synthesis of dibenzyl(5-Fluoro-2-methoxypyridin-4-yl)propanedioate (C8).

This reaction was carried out in three parallel batches. To a 25°C solution of dibenzylpropanedioate (607 g, 2.13 mol) in tetrahydrofuran (1.5 L) was added pyridine-2-carboxylic acid (35.0 g, 284 mmol) followed by the addition of copper(I) iodide (27, 1 g, 142 mmol), followed by freshly ground cesium carbonate (1.39 kg, 4.27 mol). After heating the reaction mixture to 70°C, the mixture was treated dropwise with a solution of 5-fluoro-4-iodo-2-methoxypyridine (360 g, 1.42 mol) in tetrahydrofuran (800 ml), then stirring was continued for 16 hours at 70° WITH.

The three reaction mixtures were combined at this point, cooled to 25°C and filtered through diatomaceous earth. The filter cake was washed with ethyl acetate (3 x 500 ml) and the combined filtrates were concentrated in vacuo while maintaining the internal temperature below 40°C. The residue was dissolved in ethyl acetate (2 L), washed successively with saturated aqueous ammonium chloride (500 ml) and saturated aqueous sodium chloride (500 ml), dried over sodium sulfate, filtered and concentrated under reduced pressure at 40°C. Chromatography on silica gel (gradient: 1% to 8% ethyl acetate in petroleum ether) gave C8 (1.87 kg) as a yellow oil. According to ^1H NMR analysis, this substance was contaminated with dibenzylpropanedioate; some of it was used in the next stage. LCMS m/z 410.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d), product peaks only: δ 8.01 (d, J=1.3 Hz, 1H), 7.40-7.25 (m, 10H, suspected; partially hidden by residual dibenzylpropanedioate), 6.83 (d, J=4.8 Hz, 1H), 5.20 (AB quartet, J _AB =12.2 Hz, Δν _AB =11.9 Hz, 4H), 5.00 (s , 1H), 3.89 (s, 3H).

Step 2. Synthesis of dibenzyl(5-fluoro-2-methoxypyridin-4-yl)(methyl)propanedioate (C9).

This reaction was carried out in two parallel batches. A solution of C8 (from previous step; 575 g, ≤1.31 mol) in acetonitrile (1.5 L) was stirred in an ice bath for 20 minutes, then potassium carbonate (582 g, 4.21 mol) was added. Stirring was continued for another 10 minutes. Iodomethane (302 g, 2.13 mol) was then added to the reaction mixture at 0° C. and the reaction was allowed to proceed until LCMS analysis indicated conversion to C9. The two reaction mixtures were combined, filtered through diatomaceous earth, and the filter cake was washed with acetonitrile (2 x 1 L). The combined filtrates were concentrated at 40°C and the residue was partitioned between ethyl acetate (2 L) and water (500 ml). The aqueous layer was extracted with ethyl acetate (2 x 1 L) and the combined organic layers were washed with saturated aqueous sodium chloride (1 L), dried over sodium sulfate, filtered and concentrated under reduced pressure at 40°C. The resulting crude product was dissolved in petroleum ether (1.5 L) and stirred at 0°C for 2 hours; the solid was collected by filtration. The filtrate was concentrated in vacuo and the residue was absorbed into petroleum ether (500 ml), then cooled to 0° C. to obtain additional solid, which was isolated by filtration. The two solids were combined, suspended in petroleum ether (800 ml) and stirred at 20°C for 16 hours. Subsequent collection by filtration gave C9 as a yellow solid. Yield: 670 g, 1.58 mol, 60% in 2 stages. LCMS m/z 423.8 [M+H] ⁺ . ¹ H NMR (400 MHz, chloroform-d) δ 7.94 (d, J=2.6 Hz, 1H), 7.36-7.20 (m, 10H), 6.54 (d, J=5 .1 Hz, 1H), 5.18 (s, 4H), 3.87 (s, 3H), 1.85 (s, 3H).

Step 3. Synthesis of 2-(5-fluoro-2-methoxypyridin-4-yl)propanoic acid (P6).

This reaction was carried out in four parallel batches. To a 25°C solution of C9 (200 g, 472 mmol) in ethyl acetate (1 L) was added 10% palladium on carbon (wet; 40 g). The mixture was degassed in vacuo and then purged with nitrogen; This vacuum-purging cycle was carried out a total of three times. The mixture was again degassed under vacuum and then purged with hydrogen; This vacuum-purging cycle was also carried out a total of three times. The mixture was hydrogenated (30 psi (2.109 kg/cm ^{2 )} ) at 50°C for 16 hours. The four reaction mixtures were combined and filtered through a pad of diatomaceous earth, and the filtrate was concentrated in vacuo at 45°C. Chromatography on silica gel (gradient: 10% to 20% ethyl acetate in petroleum ether) gave P6 as a white solid. Combined yield: 270 g, 1.36 mmol, 72%. LCMS m/z 199.7 [M+H] ⁺ . ¹ H NMR (400 MHz, chloroform-d) δ 7.98 (d, J=1.7 Hz, 1H), 6.70 (d, J=4.9 Hz, 1H), 3.97 (sq. , J=7.3 Hz, 1H), 3.89 (s, 3H), 1.53 (d, J=7.3 Hz, 3H).

Receiving P7 and P8

(2R)-2-(5-fluoro-2-methoxypyridin-4-yl)propanoic acid (P7) and (2S)-2-(5-fluoro-2-methoxypyridin-4-yl)propanoic acid (P8)

Separation of P6 (700 g, 3.51 mol) into its constituent enantiomers was carried out by supercritical fluid chromatography (Column: Chiral Technologies Chiralpak AD-H, 50 × 250 mm, 5 μm; Mobile phase: 9:1 carbon dioxide/2-propanol; Flow rate: 250 ml/min; Back pressure: 120 bar). The first eluting enantiomer was indicated as P7 and the second eluting enantiomer as P8; both were isolated as solids.

P7 - Yield: 260 g, 1.30 mol, 37%. Retention time: 3.17 minutes (Analytical conditions. Column: Chiral Technologies Chiralpak AD-H, 4.6 x 250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: 2-propanol; Gradient: 5% B for 1.00 minutes, then 5% to 60% B for 8 minutes; Flow rate: 3.0 ml/min; Back pressure: 120 bar).

P8 - Yield: 400 g, 2.01 mol, 57%. Retention time: 3.36 minutes (Analytical conditions identical to those used for P7).

The reported absolute stereochemistries for P7 and P8 were assigned based on comparison with the P7 sample synthesized in Alternative Preparation (#1) of P7; the configuration of this substance was established by X-ray crystallography of the resulting compound 14 (see below).

Retention time for P7 from Preparations P7 and P8: 2.86 min.

Retention time for P7 from Alternative Preparation (#1) P7: 2.86 min.

Retention time for racemic mixture f P7 and P8: 2.87 and 3.16 min.

These three analyzes were performed using the same analytical method: [Column: Chiral Technologies Chiralpak IG, 4.6 x 250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: methanol; Gradient: 5% B for 1 minute, then 5% to 60% B for 7 minutes; Flow rate: 3ml/min; Back pressure: 120 bar].

Alternative Receipt (#1) P7

(2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)propanoic acid (P7)

Stage 1. Synthesis of disodium (5-fluoro-2-methoxypyridin-4-yl)(methyl)propanedioate (C10).

A 1.0 M, pH 8.0 buffer solution was prepared as follows: a solution of 2-amino-2-(hydroxymethyl)propane-1,3-diol (Tris; 121 g, 1.00 mol) in water (900 ml) was diluted to pH 8.0 by adding hydrochloric acid (37.5 wt.%, approximately 40 ml) and then making up to 1 L volume by adding water.

The hydrogenation reactor was charged with palladium hydroxide on carbon (10%; 5.00 g). To this was added a solution of C9 (50.0 g, 118 mmol) in toluene (50 ml, 1 volume); Additional toluene (50 ml) was used to rinse the flask and this was also added to the reaction mixture. Add a mixture of aqueous sodium hydroxide (2.0 M, 118 ml, 236 mmol), pH 8.0 buffer solution described above (1.0 M; 250 ml, 250 mmol), and water (132 ml) and the resulting mixture purged with nitrogen (3.5 bar), then with hydrogen (3.5 bar); The purging method was carried out a total of three times. The mixture was brought to 20°C with stirring at 100 rpm, then the pressure was increased with hydrogen to 3.45 bar, then the stirring speed was increased to 750 rpm. After 4 hours of hydrogenation at 20°C, the stirring speed was reduced to 250 rpm and the reaction mixture was purged three times with nitrogen (3.5 bar). The catalyst was removed by filtration and the reactor was washed with water (100 ml), which was then used to wash the filter cake. The aqueous phase of the combined filtrates (590 ml, pH 8.2) containing C10 was used directly in the next step. LCMS m/z 244.2 [M+H] ⁺ .

Step 2. Synthesis of (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)propanoic acid (P7).

C10 (aqueous solution from the previous step; ≤118 mmol) was charged into a 2-L jacketed vessel (jacket temperature set at 20°C) with an overhead stirrer and the stirring speed was set at 200 rpm. Lyophilized powder solution of Bordekella bronchisepkica AMDase cell-free extract (1.75 g) [This aryl malonate decarboxylase (AMDase) from Bordekella bronchisepkica is a wild-type enzyme described in the literature, with accession number Q05115, which was recombinantly expressed in E. coli and loaded as lyophilized cell-free extract powder. References: SK GaBmeyer et al., ChemCakChem, 2016, 8, 916-921; K. Okrasa et al., Angew. Chem. Ink. Ed. 2009, 48, 7691-7694] in water (17.5 ml) was then loaded into the reactor, along with water for washing the enzyme vessel (5 ml). After 15 hours, the stirring speed was reduced to 100 rpm and the pH of the reaction mixture was adjusted to pH 6.0 by successive additions of hydrochloric acid (4.0 M, 5-ml portions, 38 ml). The mixture was stirred for 1.5 hours to stop gas evolution, then the mixture was acidified to pH ≤2.0 with additional hydrochloric acid (4.0 M, a total of 85 ml). Tert-butyl methyl ether (300 ml) was added and stirring was continued at 200 rpm for 15 minutes. The mixture was then filtered through diatomaceous earth (25 g) using a Buchner funnel and filter paper; the reactor was washed with tert-butyl methyl ether (100 ml), which was then used to wash the filter cake. The aqueous layer of the combined filtrates was extracted in the same manner with tert-butyl methyl ether (300 ml). The combined organic layers were dried over sodium sulfate (50 g) and filtered; the filter cake was washed with tert-butyl methyl ether (25 ml). The combined filtrates were concentrated in vacuo at 30°C to give an oil, which was dried in vacuo overnight to give P7 as an off-white solid. Yield: 18.88 g, 94.8 mmol, 80% in 2 stages. ¹ H NMR (400 MHz, chloroform-d) δ 11.4-10.3 (b, 1H), 7.98 (d, J=1.6 Hz, 1H), 6.70 (d, J =4.9 Hz, 1H), 3.97 (sq., J=7.2 Hz, 1H), 3.89 (s, 3H), 1.53 (d, J=7.2 Hz, 3H) .

The combination of P7 from the previous step (18.6 g, 93.4 mmol) and P7 (24.9 g, 125 mmol) from the same C10 reaction with AMDase gave a pinkish solid with an enantiomeric excess of 98.5%. ¹ H NMR (400 MHz, methanol-d ₄ ) δ 7.94 (d, J=1.9 Hz, 1H), 6.74 (d, J=5.0 Hz, 1H), 3.93 (sq. ., J=7.3 Hz, 1H), 3.87 (s, 3H), 1.48 (d, J=7.3 Hz, 3H). Retention time: 2.86 minutes [Column: Chiral Technologies Chiralpak IG, 4.6 x 250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: methanol; Gradient: 5% B for 1 minute, then 5% to 60% B for 7 minutes; Flow rate: 3ml/min; Back pressure: 120 bar].

The reported absolute stereochemistry of P7 was assigned based on the conversion of this batch of P7 into Example 14; The absolute stereochemistry of 14 was determined by single crystal X-ray diffraction (see below).

Alternate Receipt (#2) P7

(2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)propanoic acid (P7)

Step 1. Synthesis of dibenzyl(5-fluoro-2-methoxypyridin-4-yl)propanedioate (C8).

A mixture of pyridine-2-carboxylic acid (24.6 g, 0.200 mol), copper(I) iodide (19.1 g, 0.100 mol) and cesium carbonate (977 g, 3.00 mol) in tetrahydrofuran (1.26 L ; 5 volumes) was heated to an internal temperature of 60°C-70°C, then a solution of 5-fluoro-4-iodo-2-methoxypyridine (253 g, 1.00 mol) and dibenzylpropanedioate (426 g, 1.50 mol) was added. in tetrahydrofuran (250 ml, 1 volume). After heating the reaction mixture at 60°C-70°C for approximately 3-6 hours, the mixture was allowed to cool to 15°C-30°C and filtered through diatomaceous earth (250 g). The filter cake was washed with tetrahydrofuran (500 ml, 2 volumes) and the combined filtrates containing C8 were used directly in the next step. Representative data ¹ H NMR (500 MHz, chloroform-d) δ 8.00 (d, J=1.3 Hz, 1H), 7.40-7.24 (m, 10H, suspected; partially hidden by residual dibenzylpropanedioate), 6.82 (d, J=4.8 Hz, 1H), 5.20 (AB quartet, J _AB =12.3 Hz, Δν _AB =14.9 Hz, 4H), 4.99 (s, 1H) , 3.88 (s, 3H).

Step 2. Synthesis of dibenzyl(5-fluoro-2-methoxypyridin-4-yl)(methyl)propanedioate (C9).

Iodomethane (284 g, 2.00 mol) was slowly added to a 10°C-20°C mixture of cesium carbonate (977 g, 3.00 mol) and C8 solution (from the previous step, solution in tetrahydrofuran; ≤1.00 mol) . After stirring the reaction mixture at 10°C-20°C for approximately 10-12 hours, the mixture was filtered through diatomaceous earth (250 g). The filter cake was washed with tetrahydrofuran (500 ml, 1.2 volumes) and the combined filtrates were concentrated to 1-2 volumes. The resulting mixture was diluted with propan-2-yl acetate (1.25 L, 3.1 volume), washed successively with water (750 ml, 1.8 volume), aqueous ammonium chloride (20%; 750 ml) and aqueous sodium chloride ( 20%; 750 ml) and concentrated in vacuo. The remaining solvent was exchanged with heptane and precipitation from heptane (2-3 volumes) was carried out at 15°C-25°C. The resulting solid was collected by filtration and triturated with a mixture of heptane (450 ml) and propan-2-yl acetate (50 ml) to obtain C9 as a solid. The chemical reaction was carried out in three batches of steps 1 and 2 and the final C9 batches were combined. Yield: 675 g, 1.59 mol, approximately 53% in 2 steps. Representative data ¹ H NMR (500 MHz, DMSO-d ₆ ) δ 8.15 (d, J=2.0 Hz, 1H), 7.39-7.21 (m, 10H), 6.75 (d, J=5.0 Hz, 1H), 5.21 (s, 4H), 3.81 (s, 3H), 1.81 (s, 3H).

Step 3. Synthesis of disodium (5-fluoro-2-methoxypyridin-4-yl) (methyl)propanedioate (C10).

Buffer solution [pH 8.0; 2-amino-2-(hydroxymethyl)propane-1,3-diol (Tris; 121 g, 1.00 mol) and concentrated hydrochloric acid (46 ml, 0.23 volume) in water (1 L, 5 volume)] and palladium hydroxide on carbon (10%, 20 g) was added to a 15°C-25°C mixture of C9 (200 g, 0.472 mol) in toluene (400 ml, 2 volumes). A solution of sodium hydroxide (38.8 g, 0.970 mol) in water (1 L, 5 volumes) was added, then the mixture was stirred for approximately 10-20 minutes. The reactor was purged with nitrogen, then purged with hydrogen, the reaction mixture was stirred at 15°C-30°C under a hydrogen cylinder (approximately 10 L) until HPLC analysis indicated the presence of ≤0.5% C9 (approximately 22 hours) (Time retention: 11.44 minutes HPLC conditions Column: Agilent Technologies ZORBAX Eclipse Plus C18, 4.6 x 100 mm, 3.5 µm Mobile phase A: 0.1% phosphoric acid in water Mobile phase B: acetonitrile; Gradient: 5% B for 3 minutes, then 5% to 100% B for 9 minutes, then 100% B for 3 minutes; Flow rate: 1.5 ml/min). The reaction mixture was filtered and the filter cake was washed with water (2.6 volumes); the aqueous layer of filtrate containing C10 was used directly in the next step.

Step 4. Synthesis of (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)propanoic acid (P7).

A mixture of AMDase (7 g) in water (70 ml, 0.35 volume) and C10 (from the previous step, as a solution in water, ≤0.472 mol) was stirred at 15°C-30°C until HPLC analysis did not show the presence of ≤0.5% C10 (approximately 16 hours) [Retention time: 5.8 0 min. HPLC conditions are identical to those described for Step 3, Synthesis of disodium (5-fluoro-2-methoxypyridin-4-yl)(methyl)propanedioate (C10)]. Hydrochloric acid (4.0 M) was then slowly added until the reaction mixture reached a pH of 6.0, then stirring was continued for 1.5 hours. The pH was then adjusted to ≤2.0 (range 1.5-2.0) by further addition of hydrochloric acid (4.0 M). After adding tert-butyl methyl ether (1.2 L, 6 volumes), the mixture was filtered through diatomaceous earth (100 g) and the aqueous phase of the filtrate was extracted with tert-butyl methyl ether (800 ml, 4 volumes). The combined organic layers were washed with aqueous sodium chloride solution (15%; 600 ml, 3 volumes) and concentrated to 2-2.5 volumes at a temperature of ≤45°C and a pressure of ≤-0.08 MPa. N-heptane (600 ml, 3 volumes) was added and the mixture was concentrated to 3-5 volumes at a temperature of ≤45°C and a pressure of ≤-0.08 MPa; This heptane dilution/concentration was carried out a total of 3 times. After stirring the resulting mixture at 0°C-10°C for approximately 1-2 hours, the precipitate was collected by filtration to give P7 as an off-white solid with an enantiomeric excess of 99.8%. Yield: 80.0 g, 0.402 mol, 85% in 2 stages. Representative data ^1H NMR (500 MHz, chloroform-d) δ 11.68 (very broad s, 1H), 7.99 (broad s, 1H), 6.70 (d, J=4.9 Hz, 1H ), 3.97 (sq., J=7.2 Hz, 1H), 3.88 (s, 3H), 1.52 (d, J=1.3 Hz, 3H).

Getting P9

2-[5-(Difluoromethyl)-2-methoxypyridin-4-yl]propanoic acid (P9)

Stage 1. Synthesis of methyl 2-(5-bromo-2-methoxypyridin-4-yl) propanoate (C11).

A solution of sodium bis(trimethylsilyl)amide in tetrahydrofuran (2 M; 1 ml, 2 mmol) was added dropwise to a -78°C solution of methyl (5-bromo-2-methoxypyridin-4-yl) acetate (415 mg, 1.60 mmol) in tetrahydrofuran (50 ml). After stirring the reaction mixture at -78°C for 1 hour, a solution of iodomethane (0.5 ml, 8 mmol) was added dropwise. When the addition was complete, the reaction mixture was heated to -30°C and left stirring at this temperature for 3 hours, then the mixture was diluted with aqueous ammonium chloride and extracted with ethyl acetate (3 x 50 ml). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo while maintaining the temperature below 45°C. Purification by chromatography on silica gel (Eluent: 1:3 ethyl acetate/petroleum ether) gave C11 as a colorless oil. Yield: 37 6 mg, 1.37 mmol, 8 6%. LCMS w/z 276.0 (observed bromine isotopic pattern) [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.23 (s, 1H), 6.76 (s, 1H), 4.10 (q.v., J=7.1 Hz, 1H), 3, 89 (s, 3H), 3.69 (s, 3H), 1.48 (d, J=7.2 Hz, 3H).

Stage 2. Synthesis of methyl 2-(5-ethenyl-2-methoxypyridin-4-yl)propanoate (C12).

A mixture of C11 (376 mg, 1.37 mmol), potassium vinyl trifluoroborate (4 60 mg, 3.4 3 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (201 mg, 0.275 mmol) and Potassium phosphate (872 mg, 4.11 mmol) in N,N-dimethylformamide (20 ml) was stirred at 100°C for 16 hours. The reaction mixture was then filtered; the filtrate was poured into water and extracted with ethyl acetate (2 x 30 ml). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered, concentrated in vacuo and purified by chromatography on silica gel (gradient: 0% to 30% ethyl acetate in petroleum ether) to give C12 as a colorless oil. Yield: 188 mg, 0.850 mmol, 62%. LCMS m/z 222.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.21 (s, 1H), 6.81 (dd, J=17.3, 10.9 Hz, 1H), 6.63 (s, 1H), 5.56 (broadband, J=17.3 Hz, 1H), 5.32 (broadband, J=10.8 Hz, 1H), 3, 95-3, 87 (m, 1H), 3 .93 (s, 3H), 3.67 (s, 3H), 1.46 (d, J=7.1 Hz, 3H).

Step 3. Synthesis of methyl 2-(5-formyl-2-methoxypyridin-4-yl)propanoate (C13).

A solution of C12 (195 mg, 0.881 mmol) in dichloromethane (10 ml) was cooled to -78°C and then treated with a stream of ozone-enriched oxygen until a stable blue color was established. After 5 minutes, the reaction mixture was bubbled with a stream of dry nitrogen until the blue color disappeared, then triphenylphosphine (439 mg, 1.67 mmol) was added. The resulting mixture was heated to 25°C and stirred for 2 hours, then the mixture was combined with a similar reaction using C12 (63 mg, 0.28 mmol) and concentrated in vacuo. The residue was purified by silica gel chromatography (gradient: 0% to 30% ethyl acetate in petroleum ether) to give C13 as a colorless oil. Combined yield: 124 mg, 0.555 mmol, 48%. LCMS m/z 224.0 [M+H] ⁺ .

Step 4. Synthesis of methyl 2-[5-(difluoromethyl)-2-methoxypyridin-4-yl]propanoate (C14).

[Bis(2-methoxyethyl)amino]sulfur trifluoride (614 mg, 2.78 mmol) was added to a solution of C13 (124 mg, 0.555 mmol) in dichloromethane (5 mL). After stirring the reaction mixture at 25°C for 16 hours, the mixture was poured into saturated aqueous sodium bicarbonate (50 ml) and extracted with dichloromethane (50 ml). The organic layer was washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 20% ethyl acetate in petroleum ether) gave C14 as a colorless oil. Yield: 110 mg, 0.449 mmol, 81%. LCMS m/z 246.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.28 (s, 1H), 6.87 (s, 1H), 6.76 (t, J _HF =54.5 Hz, 1H), 4.11 (q, J=6.9 Hz, 1H), 4.03 (s, 3H), 3.69 (s, 3H), 1.52 (d, J=7.0 Hz, 3H).

Step 5. Synthesis of 2-[5-(difluoromethyl)-2-methoxypyridin-4-yl]propanoic acid (P9).

To a solution of C14 (145 mg, 0.591 mmol) in methanol (10 ml) was added a solution of lithium hydroxide (43 mg, 1.8 mmol) in water (4 ml) and the reaction mixture was stirred at 20°C for 4 hours, then the mixture concentrated in vacuo and washed with tert-butyl methyl ether (2 x 5 ml). The aqueous layer was adjusted to pH 5 by adding 2 M hydrochloric acid and then extracted with ethyl acetate (3 x 10 ml). The combined ethyl acetate layers were washed with water (3 x 10 ml) and saturated aqueous sodium chloride (20 ml), dried over sodium sulfate, filtered and concentrated under reduced pressure to give P9 as a yellow oil. Yield: 132 mg, 0.571 mmol, 97%. LCMS m/z 232.1 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.26 (s, 1H), 6.96 (t, J _HF =54.4 Hz, 1H), 6.84 (s, 1H), 4, 12 (sq., J=7.2 Hz, 1H), 3.94 (s, 3H), 1.48 (d, J=7.2 Hz, 3H).

Getting P10

2-fluoro-2-(2-methoxypyridin-4-yl)propanoic acid (P10)

Step 1. Synthesis of dimethyl(2-methoxypyridin-4-yl)propanedioate (C15).

To a -10°C solution of 2-methoxy-4-methylpyridine (5.00 g, 40.6 mmol) in tetrahydrofuran (30 ml) was added lithium diisopropylamide (2 M solution in tetrahydrofuran; 81.2 ml, 162 mmol). After stirring the reaction mixture at -10°C for 1.5 hours, dimethyl carbonate (14.6 g, 162 mmol) was added and stirring was continued at -10°C for 1.5 hours. The reaction mixture was then heated to 25°C and left stirring for 16 hours, then the mixture was quenched by adding an aqueous solution of ammonium chloride. The resulting mixture was extracted with ethyl acetate (3 x 30 ml) and the combined organic layers were dried over sodium sulfate, filtered and concentrated in vacuo. Purification by chromatography on silica gel (gradient: 0% to 20% ethyl acetate in petroleum ether) gave C15 as a yellow oil. Yield: 4.92 g, 20.6 mmol, 51%. LCMS m/z 240, 1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.17 (d, J=5.0 Hz, 1H), 6.95 (d, J=4.8 Hz, 1H), 6.80 (s, 1H), 4.59 (s, 1H), 3.96 (s, 3H), 3.77 (s, 6H).

Chromatographic purification also provided a mono-acylation product, methyl (2-methoxypyridin-4-yl) acetate. Yield: 1.29 g, 7.12 mmol, 18%. LCMS m/z 18 2.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.11 (bd, J=5.3 Hz, 1H), 6.81 (dd, J=5.4, 1.5 Hz, 1H), 6.68-6.66 (m, 1H), 3.93 (s, 3H), 3.71 (s, 3H), 3.57 (s, 2H).

Step 2. Synthesis of dimethyl(2-methoxypyridin-4-yl)(methyl)propanedioate (C16).

Sodium bis(trimethylsilyl)amide (2 M solution in tetrahydrofuran; 14.0 ml, 28.0 mmol) was added to a -78°C solution of C15 (4.47 g, 18.7 mmol) in tetrahydrofuran (30 ml). After stirring the reaction mixture at -78°C for 1 hour, iodomethane (1.40 ml, 22.5 mmol) was added. The reaction mixture was then heated to -40°C, stirred for 2 hours, heated to 25°C and stirred for another 16 hours, then the mixture was quenched with an aqueous solution of ammonium chloride. The resulting mixture was extracted with ethyl acetate (2 x 30 ml) and the combined organic layers were dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 10% ethyl acetate in petroleum ether) gave C16 as a yellow oil. Yield: 3.29 g, 13.0 mmol, 70%. LCMS m/z 254.1 [M+H] ⁺ . ¹ H NMR (400 MHz, chloroform-d) δ 8.15 (d, J=5.5 Hz, 1H), 6.88 (bd, J=5.5 Hz, 1H), 6.74 ( br.s, 1H), 3.95 (s, 3H), 3.78 (s, 6H), 1.83 (s, 3H).

Stage 3. Synthesis of 2-(2-methoxypyridin-4-yl)propanoic acid (C17).

A solution of C16 (3.28 g, 13.0 mmol) and lithium hydroxide (1.24 g, 51.8 mmol) in a mixture of tetrahydrofuran (20 ml) and water (10 ml) was stirred at 45°C for 5 hours. LCMS analysis indicated conversion to C17: LCMS m/z 182.1 [M+H] ⁺ and the reaction mixture was concentrated in vacuo to give C17 as a white solid (2.40 g). This substance was used directly in the next step.

Step 4. Synthesis of methyl 2-(2-methoxypyridin-4-yl)propanoate (C18).

A mixture of C17 (from the previous step; 2.40 g, ≤13.0 mmol) and sulfuric acid (2.5 ml) in methanol (25 ml) was stirred at 60°C for 16 hours. The reaction mixture was then concentrated in vacuo, washed with aqueous sodium bicarbonate and extracted with ethyl acetate (2 x 20 ml). The combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure to give C18 as a colorless oil. Yield: 1.56 g, 7.99 mmol, 61% in 2 stages. LCMS m/z 196.2 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.10 (d, J=5.4 Hz, 1H), 6.81 (dd, J=5.4, 1.5 Hz, 1H), 6, 67 (b.s, 1H), 3.93 (s, 3H), 3.67 (s, 3H), 3.66 (sq., J=7.1 Hz, 1H), 1.47 (d, J=1.2 Hz, 3H).

Step 5. Synthesis of methyl 2-fluoro-2-(2-methoxypyridin-4-yl)propanoate (C19).

To a -78°C solution of C18 (500 mg, 2.56 mmol) in tetrahydrofuran (13 ml) was added lithium bis(trimethylsilyl)amide (1 M solution in tetrahydrofuran 3.33 ml, 3.33 mmol). After stirring the reaction mixture at -78°C for 30 minutes, a solution of N-(benzenesulfonyl)-N-fluorobenzenesulfonamide (969 mg, 3.07 mmol) in tetrahydrofuran (2 ml) was added. The reaction mixture was stirred at -10°C for 3 hours, then the mixture was quenched with aqueous ammonium chloride and extracted with ethyl acetate (3 x 20 ml). The combined organic layers were dried over sodium sulfate, filtered and concentrated in vacuo; chromatography on silica gel (gradient: 0% to 10% ethyl acetate in petroleum ether) gave C19 as a yellow oil. Yield: 400 mg, 1.88 mmol, 73%. LCMS m/z 214.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.18 (d, J=5.4 Hz, 1H), 7.00 (dd, J=5.5, 1.6 Hz, 1H), 6, 88 (bd, J=1.5 Hz, 1H), 3.96 (s, 3H), 3.78 (s, 3H), 1.89 (d, JHF=22.3 Hz, 3H).

Step 6. Synthesis of 2-fluoro-2-(2-methoxypyridin-4-yl)propanoic acid (P10).

A solution of C19 (400 mg, 1.88 mmol) and lithium hydroxide (89.9 mg, 3.7 5 mmol) in a mixture of tetrahydrofuran (10 ml) and water (2 ml) was stirred at 45°C for 4 hours. The reaction mixture was then concentrated in vacuo, diluted with water (12 ml) and adjusted to pH 6 by adding 3 M hydrochloric acid. The resulting mixture was extracted with ethyl acetate (2 x 20 ml) and the combined organic layers were dried over sodium sulfate, filtered and concentrated under reduced pressure to give P10 as a yellow oil. Yield: 300 mg, 1.51 mmol, 80%. LCMS m/z 200.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 9.9-9.4 (b.s, 1H), 8.21 (d, J=5.6 Hz, 1H), 7.08 (dd, J =5.6, 1.6 Hz, 1H), 6.95 (b.s, 1H), 3.95 (s, 3H), 1.92 (d, J _HF =22.2 Hz, 3H).

Getting P11

2-[3-(Difluoromethoxy)-5-methoxyphenyl]propanoic acid (P11)

Stage 1. Synthesis of 1-(difluoromethoxy)-3-methoxy-5-methylbenzene (C20).

Aqueous potassium hydroxide (20% solution; 60.9 g, 217 mmol) and [bromo(difluoro)methyl](trimethyl)silane (11.3 mL, 72.7 mmol) were added sequentially to the 0°C solution of 3-methoxy -5-methylphenol (5.00 g, 36.2 mmol) in dichloromethane (50 ml). After stirring the reaction mixture at 0°C for 4.5 hours, the mixture was diluted with water (50 ml) and extracted with dichloromethane (3 x 100 ml). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered, concentrated in vacuo and purified by chromatography on silica gel (gradient: 0% to 5% ethyl acetate in petroleum ether) to give C20 as a colorless oil. Yield: 6.27 g, 33.3 mmol, 92%. ^1H NMR (400 MHz, methanol-d ₄ ) δ 6.76 (t, J _HF =74.4 Hz, 1H), 6.60 (br.s, 1H), 6.53 (b.s, 1H ), 6.49-6.46 (m, 1H), 3.76 (s, 3H), 2.30 (s, 3H).

Step 2. Synthesis of 1-(bromomethyl)-3-(difluoromethoxy)-5-methoxybenzene (C21).

Mixture of C20 (3.00 g, 15.9 mmol), 2,2'-azobisobutyronitrile (262 mg, 1.60 mmol) and N-bromosuccinimide (2.84 g, 15.9 mmol) in carbon tetrachloride (90 ml) stirred at 80°C for 8 hours. Concentration in vacuo gave C21 as a yellow oil. Yield: 4.0 g, 15 mmol, 94%. ^1H NMR (400 MHz, methanol- _d4 ), product peaks only, characteristic peaks: 5 6.84 (s, 1H), 6.77 (s, 1H), 6.63-6.60 (m, 1H ), 4.50 (s, 2H), 3.81 (s, 3H).

Step 3. Synthesis of [3-(difluoromethoxy)-5-methoxyphenyl]acetonitrile (C22).

To a solution of C21 (4.0 g, 15 mmol) in acetonitrile (150 ml) potassium carbonate (3.11 g, 22.5 mmol) and trimethylsilyl cyanide (2.2 g, 22 mmol) were successively added. The resulting mixture was stirred at 80°C for 16 hours, after which LCMS analysis showed the presence of C22: LCMS m/z 214.1 [M+H] ⁺ . The reaction mixture was concentrated under reduced pressure, diluted with water (50 ml) and extracted with ethyl acetate (3 x 50 ml). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, concentrated in vacuo and purified by chromatography on silica gel (gradient: 0% to 30% ethyl acetate in petroleum ether) to give C22 as a yellow oil. Yield: 1.20 g, 5.63 mmol, 38%. ¹ H NMR (400 MHz, methanol-d ₄ ) δ 6.84 (t, J _HF = 73.9 Hz, 1H), 6.81 (br.s, 1H), 6.7 3 (b.s, 1H), 6.68-6.66 (m, 1H), 3.89 (s, 2H), 3.82 (s, 3H).

Step 4. Synthesis of 2-[3-(difluoromethoxy)-5-methoxyphenyl]propanenitrile (C23).

Conversion of C22 (3.00 g, 14.1 mmol) to C23 was carried out using the procedure described for the synthesis of C16 from C15 in Preparation P10. Chromatography on silica gel (gradient: 0% to 5% ethyl acetate in petroleum ether) gave C23 as a yellow oil. Yield: 1.00 g, 4.40 mmol, 31%. LCMS m/z 228.1 [M+H] ⁺ . ^1H NMR (400 MHz, methanol-d ₄ ) δ 6.85 (t, J _HF =73.9 Hz, 1H), 6.84-6.82 (m, 1H), 6.77-6.74 (m, 1H), 6.69-6.66 (m, 1H), 4.11 (sq., J=7.2 Hz, 1H), 3.82 (s, 3H), 1.60 (d , J=7.3 Hz, 3H).

Step 5. Synthesis of ethyl 2-[3-(difluoromethoxy)-5-methoxyphenyl]propanoate (C24).

Thionyl chloride (5.3 ml, 73 mmol) was added dropwise to a 0°C solution of C23 (900 mg, 3.96 mmol) in ethanol (40 ml). The reaction mixture was stirred at 85°C for 16 hours, then the mixture was diluted with water (50 ml) and extracted with ethyl acetate (3 x 30 ml). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 6% ethyl acetate in petroleum ether) gave C24 (700 mg, 2.55 mmol, 64%) as a yellow oil. Yield: 700 mg, 2.55 mmol, 64%. LCMS m/z 275.1 [M+H] ⁺ . ^1H NMR (400 MHz, methanol-d ₄ ) δ 6.80 (t, J _HF =74.2 Hz, 1H), 6.74-6.71 (m, 1H), 6.65 (b.s , 1H), 6.59 (dd, J=2.2, 2.2 Hz, 1H), 4.19-4.05 (m, 2H), 3.79 (s, 3H), 3.72 ( sq., J=7.2 Hz, 1H), 1.44 (d, J=7.2 Hz, 3H), 1.20 (t, J=1.1 Hz, 3H).

Step 6. Synthesis of 2-[3-(difluoromethoxy)-5-methoxyphenyl]propanoic acid (P11).

To a solution of C24 (700 mg, 2.55 mmol) in tetrahydrofuran (30 ml) was added a solution of lithium hydroxide monohydrate (535 mg, 12.8 mmol) in water (10 ml). After stirring the reaction mixture at 25°C for 16 hours, the mixture was concentrated in vacuo, diluted with water (20 ml) and washed with dichloromethane (3 x 25 ml). These organic layers were drained. The aqueous layer was adjusted to pH approximately 2 using 2 M hydrochloric acid; the mixture was then extracted with dichloromethane (3 x 25 ml). The combined organic layers were washed with saturated aqueous sodium chloride (10 ml), dried over sodium sulfate, filtered and concentrated under reduced pressure to give P11 as a yellow oil. Yield: 62 8 mg, 2.55 mmol, quantitative. LCMS m/z 247.1 [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ) δ 6.79 (t, J _HF =74.2 Hz, 1H), 6.77-6.73 (m, 1H), 6.69-6.66 (m, 1H), 6.59 (dd, J=2.2, 2.2 Hz, 1H), 3.79 (s, 3H), 3.69 (sq., J=7.2 Hz, 1H ), 1.44 (d, J=7.2 Hz, 3H).

Getting P12

2-[5-Fluoro-2-(trifluoromethoxy)pyridin-4-yl]propanoic acid (P12)

Step 1. Synthesis of diethyl (5-fluoro-2-methoxypyridin-4-yl)propanedioate (C25).

The reaction of 5-fluoro-4-iodo-2-methoxypyridine (3.45 g, 13.6 mmol) with diethylpropanedioate (3.28 g, 20.5 mmol) was carried out using the method described for the synthesis of C6 from C5 in Preparation P5 . Purification by chromatography on silica gel (gradient: 0% to 15% ethyl acetate in petroleum ether) gave C25 as a colorless oil. Yield: 2.80 g, 9.82 mmol, 72%. LCMS w/z 286, 1 [M+N] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.00 (b.s, 1H), 6.84 (b.d, J=4.8 Hz, 1H), 4.87 (s, 1H), 4.30-4.21 (m, 4H), 3.90 (s, 3H), 1.28 (t, J=7.1 Hz, 6H).

Step 2. Synthesis of diethyl (5-fluoro-2-methoxypyridin-4-yl) (methyl)propanedioate (C26).

To a solution of C25 (2.80 g, 9.82 mmol) in acetonitrile (100 ml) was added potassium carbonate (4.07 g, 29.4 mmol) followed by dropwise addition of iodomethane (2.09 g, 14.7 mmol ). The reaction mixture was stirred at 25°C for 2 days, then LCMS analysis showed conversion to C26: LCMS m/z 300.1 [M+H] ⁺ . The reaction mixture was poured into water (1 L) and extracted with ethyl acetate (2 x 100 ml); the combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo to give C26 as a yellow oil. Yield: 2.25 g, 7.52 mmol, 77%. ^1H NMR (400 MHz, chloroform-d) δ 7.95 (d, J=2.7 Hz, 1H), 6.58 (d, J=5.2 Hz, 1H), 4.30-4, 22 (m, 4H), 3.90 (s, 3H), 1.81 (s, 3H), 1.27 (t, J=1.1 Hz, 6H).

Step 3. Synthesis of diethyl (5-fluoro-2-hydroxypyridin-4-yl) (methyl)propanedioate (C27).

Trimethylsilyl iodide (7.52 g, 37.6 mmol) was added dropwise to a solution of C26 (2.25 g, 7.52 mmol) in acetonitrile (100 ml) and the reaction mixture was stirred at 100°C for 4 hours, then LCMS analysis showed conversion to C27: LCMS m/z 286.1 [M+H] ⁺ . The reaction mixture was poured into aqueous sodium bicarbonate (100 ml) and the resulting mixture was extracted with ethyl acetate (3 x 100 ml). The combined organic layers were washed with aqueous sodium dithionite (200 ml), filtered, concentrated in vacuo and purified by silica gel chromatography (gradient: 0% to 15% methanol in dichloromethane) to give C27 as a white solid. Yield: 685 mg, 2.40 mmol, 32%. ^1H NMR (400 MHz, chloroform-d) δ 7.29-7.26 (m, 1H, presumably; partially hidden by solvent peak), 6.43 (d, J=6.4 Hz, 1H), 4, 35-4.19 (m, 4H), 1.80 (s, 3H), 1.27 (t, J=1.1 Hz, 6H).

Step 4. Synthesis of diethyl[5-fluoro-2-(trifluoromethoxy)pyridin-4-yl](methyl)propanedioate (C28).

A solution of 1-trifluoromethyl-1,2-benziodxol-3-(1H)-one (759 mg, 2.40 mmol) and C27 (685 mg, 2.40 mmol) in nitromethane (20 ml) was stirred at 100°C in within 16 hours. After removal of the solvent in vacuo, the residue was purified by chromatography on silica gel (gradient: 0% to 20% ethyl acetate in petroleum ether) to give C28 as a colorless oil. Yield: 283 mg, 0.801 mmol, 33%. LCMS m/z 354.0 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.13 (d, J=2.3 Hz, 1H), 6.93 (d, J=5.0 Hz, 1H), 4.34-4, 22 (m, 4H), 1.85 (s, 3H), 1.28 (t, J=7.1 Hz, 6H).

Step 5. Synthesis of 2-[5-fluoro-2-(trifluoromethoxy)pyridin-4-yl]propanoic acid (P12).

To a solution of C28 (300 mg, 0.84 9 mmol) in tetrahydrofuran (10 ml) was added a solution of lithium hydroxide (102 mg, 4.26 mmol) in water (3 ml) at 25°C. After stirring the reaction mixture at 25°C for 16 hours, the mixture was combined with a similar reaction using C28 (50 mg, 0.14 mmol), diluted with water (100 ml) and washed with dichloromethane (3 x 50 ml). These organic layers were drained. The aqueous layer was adjusted to pH 5 by adding 5 M hydrochloric acid and extracted with dichloromethane (3 x 50 ml); the combined dichloromethane layers were concentrated in vacuo to give P12 as a white solid. Combined yield: 230 mg, 0.909 mmol, 92%. LCMS m/z 254.0 [M+H] ^- . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.17 (d, J=1.5 Hz, 1H), 7.20 (d, J=4.8 Hz, 1H), 4.05 (kv ., J=7.3 Hz, 1H), 1.53 (d, J=7.3 Hz, 3H).

Getting P13

2-[2-(Difluoromethoxy)-5-fluoropyridin-4-yl]propanoic acid (P13)

Stage 1. Synthesis of methyl 2-(5-fluoro-2-methoxypyridin-4-yl) propanoate (C29).

Sulfuric acid (0.2 ml) was added to a solution of P6 (1.80 g, 9.04 mmol) in methanol (20 ml) and the reaction mixture was stirred at 70°C for 12 hours, then the mixture was concentrated under reduced pressure. The residue was treated with saturated aqueous sodium bicarbonate (30 ml) until pH=8 and then the mixture was extracted with ethyl acetate (3 x 30 ml). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo to give C29 as a colorless oil. Yield: 1.85 g, 8.68 mmol, 96%. LCMS m/z 214.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.94 (b.s, 1H), 6.65 (d, J=5.0 Hz, 1H), 3.93 (q.v., J=7, 3 Hz, 1H), 3.89 (s, 3H), 3.69 (s, 3H), 1.49 (d, J=7.3 Hz, 3H).

Stage 2. Synthesis of methyl 2-(5-fluoro-2-hydroxypyridin-4-yl)propanoate (C30).

A solution of C29 (700 mg, 3.2 8 mmol) and trimethylsilyl iodide (1.97 g, 9.85 mmol) in acetonitrile (10 ml) was stirred at 80°C for 4 hours. The reaction mixture was concentrated in vacuo, then the residue was purified by silica gel chromatography (gradient: 0% to 10% methanol in dichloromethane) to give C30 as a pale brown oil. Yield: 550 mg, 2.76 mmol, 84%. LCMS m/z 200.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.99 (d, J=3.5 Hz, 1H), 6.93 (d, J=5.8 Hz, 1H), 3.99 (sq. , J=7.2 Hz, 1H), 3.75 (s, 3H), 1.58 (d, J=7.2 Hz, 3H).

Step 3. Synthesis of methyl 2-[2-(difluoromethoxy)-5-fluoropyridin-4-yl]propanoate (C31).

A mixture of C30 (580 mg, 2.91 mmol) and sodium chloro(difluoro)acetate (888 mg, 5.82 mmol) in acetonitrile (10.0 ml) was stirred at 100°C for 12 hours. The reaction mixture was then concentrated in vacuo and chromatographed on silica gel (gradient: 0% to 30% ethyl acetate in petroleum ether) to give C31 as a colorless oil. Yield: 550 mg, 2.21 mmol, 76%. LCMS m/z 250.1 [M+H] ⁺ . ¹ H NMR (400 MHz, chloroform-d) δ 7.99 (d, J=1.3 Hz, 1H), 7.36 (t, J _HF =72.9 Hz, 1H), 6.86 (d , J=4.8 Hz, 1H), 3.99 (sq., J=7.3 Hz, 1H), 3.72 (s, 3H), 1.53 (d, J=1.3 Hz, 3H).

Step 4. Synthesis of 2-[2-(difluoromethoxy)-5-fluoropyridin-4-yl]propanoic acid (P13).

A solution of lithium hydroxide monohydrate (455 mg, 10.8 mmol) in water (5 ml) was added to a solution of C31 (1.00 g, 4.01 mmol) in tetrahydrofuran (10 ml). The reaction mixture was stirred at 25°C for 10 hours, then the mixture was concentrated under reduced pressure and the aqueous residue was washed with dichloromethane (3 x 10 ml). The aqueous layer was then adjusted to pH 7 by adding 1 M hydrochloric acid and the resulting mixture was extracted with ethyl acetate (3 x 30 ml). The combined ethyl acetate layers were concentrated in vacuo to give P13 as a colorless oil. Yield: 830 mg, 3.53 mmol, 88%. LCMS m/z 236.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.99 (b.s, 1H), 7.35 (t, J _HF =72.8 Hz, 1H), 6.86 (d, J=4, 8 Hz, 1H), 3.98 (sq., J=7.2 Hz, 1H), 1.52 (d, J=1.3 Hz, 3H).

Getting P14

2-[2-(Dimethylamino)-5-fluoropyridin-4-yl]propanoic acid (P14)

Step 1. Synthesis of tert-butyl (2-chloro-5-fluoropyridin-4-yl) acetate (C32).

Lithium diisopropylamide (2 M solution in tetrahydrofuran; 50.5 ml, 101 mmol) was added to a -78°C solution of 2-chloro-5-fluoro-4-methylpyridine (4.90 g, 33.7 mmol) in tetrahydrofuran (200 ml). After stirring the reaction mixture at -50°C for 1 hour, the mixture was cooled to -78°C and a solution of di-tert-butyl dicarbonate (8.51 ml, 37.0 mmol) in tetrahydrofuran (30 ml) was added. The reaction mixture was then heated to -30°C, stirred for 2 hours and diluted with water (100 ml). The resulting mixture was extracted with ethyl acetate (3 x 50 ml); the combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 10% ethyl acetate in petroleum ether) gave C32 as an oil. Yield: 4.90 g, 19.9 mmol, 59%. LCMS m/z 246.1 (observed chlorine isotope pattern) [M+H] ⁺ . ¹ H NMR (400 MHz, chloroform-d) δ 8.21 (b.s, 1H), 7.29 (d, J=5.2 Hz, 1H), 3.59 (s, 2H), 1, 46 (s, 9H).

Stage 2. Synthesis of tert-butyl-2-(2-chloro-5-fluoropyridin-4-yl)propanoate (C33).

Conversion of C32 (4.60 g, 18.7 mmol) to C33 was carried out using the method described for the synthesis of C16 from C15 in Preparation P10. Chromatography on silica gel (gradient 0% to 20% ethyl acetate in petroleum ether) gave C33 as an oil. Yield: 4.40 g, 16.9 mmol, 90%. LCMS m/z 262.1 (observed chlorine isotope pattern) [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.19 (b.s, 1H), 7.28 (d, J=5.1 Hz, 1H), 3.87 (q.v., J=7, 3 Hz, 1H), 1.48 (d, J=7.2 Hz, 3H), 1.42 (s, 9H).

Step 3. Synthesis of 2-[2-(dimethylamino)-5-fluoropyridin-4-yl]propanoic acid (P14).

Mixture of C33 (3.00 g, 11.6 mmol), dimethylamine (2 M solution in tetrahydrofuran; 8.66 ml, 17.3 mmol), tris(dibenzylideneacetone)dipalladium(0) (1.06 g, 1.16 mmol), 2-dicyclohexylphosphino-2',6'-diisopropoxybiphenyl (RuPhos; 1.08 g, 2.31 mmol) and sodium tert-butoxide (3.33 g, 34.7 mmol) in toluene (100 ml) were stirred at 100°C for 16 hours. The reaction mixture was concentrated in vacuo, then the mixture was diluted with water and washed with dichloromethane (3 x 30 ml). The aqueous layer was then adjusted to pH 5 by adding 5 M hydrochloric acid and extracted with ethyl acetate (2 x 50 ml). The combined ethyl acetate layers were dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 10% methanol in dichloromethane) gave P14 as a gray solid. Yield: 700 mg, 3.30 mmol, 2 8%. LCMS m/z 213.1 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 7.87 (d, J=2.1 Hz, 1H), 6.57 (d, J=4.9 Hz, 1H), 3.90 (sq. ., J=7.2 Hz, 1H), 3.04 (s, 6H), 1.48 (d, J=7.2 Hz, 3H).

Getting P15

Lithium 2-(5-Chloro-2-methoxypyrimidin-4-yl)propanoate (P15)

Step 1. Synthesis of dimethyl (2,5-dichloropyrimidin-4-yl) (methyl)propanedioate (C34).

Sodium hydride (60% dispersion in mineral oil; 1.31 g, 33 mmol) was slowly added to a 0°C solution of dimethyl methylpropanedioate (4.78 g, 32.7 mmol) in tetrahydrofuran (40 ml). The reaction mixture was stirred at 0°C for 30 minutes, then a solution of 2,4,5-trichloropyrimidine (5.00 g, 27.3 mmol) in tetrahydrofuran (10 ml) was added dropwise at 0°C. Stirring was continued at 0°C for 30 minutes, then the reaction mixture was slowly heated to 25°C and left to stir at this temperature for 30 minutes. After adding saturated aqueous ammonium chloride (100 ml), the mixture was extracted with ethyl acetate (3 x 100 ml). The combined organic layers were washed successively with water and saturated aqueous sodium chloride, then combined with the organic layer from the same reaction using 2,4,5-trichloropyrimidine (500 mg, 2.73 mmol), dried over sodium sulfate, filtered and concentrated in vacuo, maintaining the temperature below 40°C. Chromatography on silica gel (gradient: 10% to 13% ethyl acetate in petroleum ether) gave C34 as a colorless oil. Combined yield: 6.82 g, 23.3 mmol, 78%. LCMS m/z 293.0 (observed dichloro-isotopic pattern) [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ) δ 8.74 (s, 1H), 3.79 (s, 6H), 1.90 (s, 3H).

Step 2. Synthesis of dimethyl (5-chloro-2-methoxypyrimidin-4-yl)(methyl)propanedioate (C35).

A solution of sodium methoxide in methanol (30% solution; 4.66 g, 26 mmol) was added dropwise to a solution of C34 (6.32 g, 21.6 mmol) in methanol (120 ml). After stirring the reaction mixture at 25°C for 2 hours, the mixture was concentrated in vacuo, maintaining the temperature below 40°C, diluted with water (50 ml) and extracted with ethyl acetate (2 x 100 ml). The organic layers were combined with layers from the same reaction carried out using C34 (500 mg, 1.71 mmol), washed successively with water and saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 11% to 15% ethyl acetate in petroleum ether) gave C35 as a colorless oil. Combined yield: 4.00 g, 13.9 mmol, 60%. LCMS m/z 289.0 (observed chlorine isotope pattern) [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ) δ 8.53 (s, 1H), 3.95 (s, 3H), 3.79 (s, 6H), 1.88 (s, 3H).

Stage 3. Synthesis of 2-(5-chloro-2-methoxypyrimidin-4-yl) lithium propanoate (P15).

A solution of lithium hydroxide monohydrate (1.65 g, 39.3 mmol) in water (20 ml) was added dropwise to a solution of C35 (3.78 g, 13.1 mmol) in tetrahydrofuran (60 ml). The reaction mixture was stirred at 35°C for 3 hours, then the mixture was concentrated in vacuo. The resulting aqueous mixture was washed with dichloromethane and then purified by reverse phase chromatography (column: C18; gradient: 0% to 10% acetonitrile in water) to obtain P15 as a white solid. Yield: 1.87 g, 8.40 mmol, 64%. LCMS m/z 217.1 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.37 (s, 1H), 4.05 (sq., J=7.2 Hz, 1H), 4.00 (s, 3H), 1, 55 (d, J=7.2 Hz, 3H).

Getting P16

2-[2-(Difluoromethoxy)-6-methoxypyridin-4-yl]propanoic acid (P16)

Step 1. Synthesis of methyl 2-(difluoromethoxy)-6-methoxypyridine-4-carboxylate (C36).

Methyl 2-hydroxy-6-methoxypyridin-4-carboxylate (900 mg, 4.91 mmol) was converted to C36 using the method described for the synthesis of C5 from 5-iodopyridin-2-ol in Preparation P5. Chromatography on silica gel (gradient: 0% to 8% ethyl acetate in petroleum ether) gave C36 as a colorless oil. Yield: 720 mg, 3.09 mmol, 63%. LCMS m/z 234.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.39 (t, J _HF =73.0 Hz, 1H), 7.10 (br.s, 1H), 7.00 (b.s, 1H) , 3.94 (s, 3H), 3.93 (s, 3H).

Step 2. Synthesis of 2-(difluoromethoxy)-6-methoxypyridine-4-carboxylic acid (C37).

Using the method described for the synthesis of P11 from C24 in Preparation of P11, C36 (1.10 g, 4.72 mmol) was hydrolyzed to yield C37 as a white solid. Yield: 980 mg, 4.47 mmol, 95%. LCMS m/z 220, 1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.41 (t, J _HF =72.8 Hz, 1H), 7.15 (d, J=1.1 Hz, 1H), 7.05 (d , J=1.0 Hz, 1H), 3.95 (s, 3H).

Step 3. Synthesis of methyl[2-(difluoromethoxy)-6-methoxypyridin-4-yl]acetate (C33).

A solution of C37 (980 mg, 4.47 mmol) in thionyl chloride (6.49 ml, 89.0 mmol) was stirred at 70°C for 2.5 hours, then the mixture was concentrated under reduced pressure. The resulting acyl chloride was dissolved in a mixture of tetrahydrofuran (8 ml) and acetonitrile (8 ml), then the mixture was cooled to 0°C and treated with freshly distilled triethylamine (0.87 ml, 6.2 mmol) and then (diazomethyl)(trimethyl)silane ( 2 M solution in diethyl ether; 3.35 ml, 6.70 mmol). The reaction mixture was stirred at 0°C for 8 hours, then the mixture was diluted with diethyl ether (25 ml) and washed successively with 10% aqueous citric acid (5 ml), saturated aqueous sodium bicarbonate (15 ml) and saturated aqueous sodium chloride (25 ml). The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure to obtain crude diazoketone. This substance was suspended in methanol (10 ml) in an ultrasonic bath; A solution of silver benzoate (512 mg, 2.24 mmol) in triethylamine (1.86 ml, 13.3 mmol) was gradually added at room temperature while the reaction mixture was sonicated. After 30 minutes, the volatiles were removed in vacuo and the residue was purified by chromatography on silica gel (gradient: 0% to 10% ethyl acetate in petroleum ether) to give C38 as a colorless oil. Yield: 340 mg, 1.38 mmol, 31%. LCMS m/z 248.0 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.40 (t, J _HF =73.4 Hz, 1H), 6.45 (br.s, 1H), 6.40 (b.s, 1H) , 3.88 (s, 3H), 3.71 (s, 3H), 3.57 (s, 2H).

Step 4. Synthesis of methyl 2-[2-(difluoromethoxy)-6-methoxypyridin-4-yl]propanoate (C39).

To a -78°C solution of C38 (230 mg, 0.930 mmol) in tetrahydrofuran (20 ml) was added sodium bis(trimethylsilyl)amide (2 M solution in tetrahydrofuran; 0.56 ml, 1.1 mmol) and the reaction mixture was stirred at - 78°C for 1 hour. Iodomethane (57.9 μl, 0.93 mmol) was then added and stirring was continued for 2 hours at -78°C. After adding saturated aqueous ammonium chloride (10 mL), the mixture was combined with a similar reaction using C38 (100 mg, 0.405 mmol) and extracted with ethyl acetate (3 x 20 mL). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo; chromatography on silica gel (gradient: 0% to 4% ethyl acetate in petroleum ether) gave C39 as a colorless oil. Combined yield: 150 mg, 0.574 mmol, 43%. LCMS m/z 262.1 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 7.51 (t, J _HF = 73.3 Hz, 1H), 6.50 (bd, J = 1 Hz, 1H), 6.43 ( broad.d, J=1 Hz, 1H), 3.88 (s, 3H), 3.78 (sq., J=7.2 Hz, 1H), 3.68 (s, 3H), 1.44 (d, J=7.2 Hz, 3H).

Step 5. Synthesis of 2-[2-(difluoromethoxy)-6-methoxypyridin-4-yl]propanoic acid (P16).

Hydrolysis of C39 (130 mg, 0.4-98 mmol) was carried out using the method described for the synthesis of P12 from C28 in Preparation of P12, yielding P16 as a colorless oil. Yield: 101 mg, 0.409 mmol, 82%. LCMS m/z 248.0 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 7.51 (t, J _HF = 73.3 Hz, 1 H), 6.53 (bd, J = 1.1 Hz, 1 H), 6, 46 (br.d, J=1.1 Hz, 1H), 3.88 (s, 3H), 3.72 (sq., J=7.1 Hz, 1H), 1.44 (d, J= 7.2 Hz, 3H).

Receiving P17 and P18

tert-Butyl-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P17) and di-tert-butyl-7-methyl- 3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1,1'-dicarboxylate (P18)

Stage 1. Synthesis of 2-chloro-3-iodo-6-methylpyridine (C40).

To 0°C a mixture of 2-chloro-6-methylpyridin-3-amine (400 g, 2.80 mol) in water (5.0 l) and hydrochloric acid (5.0 M; 3.3 l, 16.5 mol) a solution of sodium nitrite (290 g, 4.20 mol) in water (800 ml) was added dropwise at a rate that maintained the internal reaction temperature below 5°C. The reaction mixture was stirred with ice cooling for 30 minutes, then cooled to -5°C, then tert-butyl methyl ether (3.0 L) was added, followed by dropwise addition of a solution of potassium iodide (929 g, 5.60 mol) in water (800 ml), maintaining the internal reaction temperature below 10°C. The reaction mixture was then allowed to slowly warm to 25°C and stirring was continued at 25°C for 16 hours. After adjusting the pH to 9 by adding 2 M aqueous sodium hydroxide, the mixture was extracted with ethyl acetate (3 x 2.0 L); the combined organic layers were washed twice with aqueous sodium sulfite and once with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. Purification by silica gel chromatography (gradient: 0% to 5% ethyl acetate in petroleum ether) gave C40 as a white solid. Yield: 610 g, 2.41 mol, 8 6%. LCMS m/z 2 53.9 (observed chlorine isotope pattern) [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.13 (d, J=7.9 Hz, 1H), 6.96 (d, J=7.9 Hz, 1H), 2.44 (s , 3H).

Step 2. Synthesis of 1-benzyl-3-[(trimethylsilyl)ethynyl]pyrrolidin-3-ol (C41).

A solution of n-butyllithium in tetrahydrofuran (2.5 M; 3.75 L, 9.4 mol) was added dropwise to a -78°C solution of ethynyl(trimethyl)silane (1.01 kg, 10.3 mol) in tetrahydrofuran ( 4.0 l). The reaction mixture was stirred at -78°C for 1 hour, then a solution of 1-benzylpyrrolidin-3-one (1.50 kg, 8.56 mol) in tetrahydrofuran (1.5 L) was added dropwise. After addition was completed, the reaction mixture was heated to 20°C, stirred at 20°C for 16 hours and then poured into an aqueous ammonium chloride solution. The resulting mixture was extracted with ethyl acetate (2 x 2.0 L) and the combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo to give C41 as a yellow oil. Yield: 2.25 kg, 8.23 mol, 96%. LCMS m/z 274.2 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 7.37-7.28 (m, 4H), 7.28-7.22 (m, 1H), 3.66 (AB quartet, J _AB =12 .7 Hz, Δ v _AB =12.2 Hz, 2H), 2.89-2.77 (m, 3H), 2.65 (ddd, J=9.4, 7.9, 5.5 Hz, 1H), 2.30-2.21 (m, 1H), 2.12-2.03 (m, 1H), 0.14 (s, 9H).

Step 3. Synthesis of 1-benzyl-3-ethynylpyrrolidin-3-ol (C42).

A mixture of C41 (2.77 kg, 10.1 mol) and potassium carbonate (2.80 kg, 20.3 mol) in methanol (10 L) was stirred at 25°C for 3 hours, then the reaction mixture was filtered and the filtrate was concentrated in a vacuum. The residue was diluted with ethyl acetate (10 L) and the mixture was filtered. Concentrating this filtrate under reduced pressure gave C42 as a black oil (2.30 kg). This substance was used directly in the next step. LCMS m/z 202.2 [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ), characteristic peaks: 57.37-7.28 (m, 4H), 7.28-7.22 (m, 1H), 3.66 (AB quartet, J _AB =12.7 Hz, Δ v _AB =12.7 Hz, 2H), 2.89-2.78 (m, 3H), 2.65 (ddd, J=9.4, 7.9, 5, 7 Hz, 1H), 2.27 (ddd, J=13.3, 7.9, 6.8 Hz, 1H), 2.14-2.04 (m, 1H).

Step 4. Synthesis of 1-benzyl-3-ethynylpyrrolidin-3-ylanetate (C43).

Acetyl chloride (1.35 kg, 17 .2 mol) drop by drop. The reaction mixture was then stirred at 25°C for 30 minutes, then water (10 L) was added. The resulting mixture was extracted with dichloromethane (2 x 3.0 L) and the combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo to give C43 as a brown oil (2.82 kg). Part of this substance was used in the next stage. LCMS m/z 244.2 [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ) δ 7.38-7.23 (m, 5H), 3.65 (s, 2H), 3.05 (s, 2H), 3.03 (s, 1H), 2.77 (ddd, J=9.5, 7.4, 6.1 Hz, 1H), 2.66 (ddd, J=9.5, 7.4, 6.5 Hz, 1H) , 2.46 (ddd, J=13.6, 7.4, 6.1 Hz, 1H), 2.40-2.31 (m, 1H), 2.02 (s, 3H).

Step 5. Synthesis of 1-benzyl-3-ethynyl-N-[(4-methoxyphenyl)methyl]pyrrolidin-3-amine (C44).

A mixture of C43 (from the previous step; 1.20 kg, ≤4.30 mol), 1-(4-methoxyphenyl)methanamine (1.35 kg, 9.8 4 mmol) and copper(I) chloride (48.8 g , 0.493 mol) in tetrahydrofuran (6.0 L) was degassed in vacuo and then purged with nitrogen; This vacuum-purging cycle was carried out a total of three times. The reaction mixture was then stirred at reflux for 45 minutes, then the mixture was concentrated in vacuo. This material was combined with that from three similar reactions using C43 (from the previous step; 900 g C43 used in three reactions, ≤3.2 mol) and purified by silica gel chromatography (gradient: 0% to 50% ethyl acetate in petroleum ether) to obtain C44 as a brown oil. Combined yield: 620 g, 1.93 mol, 26% over 3 steps. LCMS m/z 321.3 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ,) δ 7.36-7.21 (m, 7H), 6.85 (bd, J=8.7 Hz, 2H), 3.81-3 .69 (m, 2H), 3.77 (s, 3H), 3.65 (AB quartet, J _AB =12.7 Hz, Δ v _AB =9.9 Hz, 2H), 2.88 (s, 1H), 2, 82-2, 67 (m, 2H), 2.79 (AB quartet, dAB=9.8 Hz, Δ v _AB =37.8 Hz, 2H), 2.27 (ddd, J= 13.4, 7.7, 6.0 Hz, 1H), 2.09-2.01 (m, 1H).

Step 6. Synthesis of 1-benzyl-3-[(2-chloro-6-methylpyridin-3-yl)ethynyl]-N-[(4-methoxyphenyl)methyl]pyrrolidin-3-amine (C45).

A mixture of C44 (426 g, 1.33 mol), C40 (303 g, 1.20 mmol), dichlorobis(triphenylphosphine)palladium(II) (46.6 g, 66.4 mmol) and copper(I) iodide (12 .6 g, 66.2 mmol) in triethylamine (2.0 L) was degassed in vacuo and then purged with nitrogen; This vacuum-purging cycle was carried out a total of three times. The reaction mixture was stirred at reflux for 16 hours, then the mixture was filtered; the filtrate was concentrated in vacuo and combined with material from two similar reactions, which were carried out using C40 (12.17 g, 48.0 mmol; 146 g, 0.576 mol). The resulting mixture was purified by silica gel chromatography (gradient: 20% to 50% ethyl acetate in petroleum ether) to give C45 as a black oil. Combined yield: 420 g, 0.94 2 mol, 52%. LCMS m/z 446.2 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 7.80 (d, J=7.8 Hz, 1H), 7.39-7.20 (m, 8H), 6.86 (d, J= 8.6 Hz, 2H), 3.87 (AV quartet, J _AB =12.0 Hz, Δ v _AB =29.6 Hz, 2H), 3.76 (s, 3H), 3.70 (AV quartet , J _AB =13.0 Hz, Δ v _AB =9.3 Hz, 2H), 3.00 (d, AB quartet component, J = 9.9 Hz, 1H), 2.87-2.77 (m , 3H), 2.51 (s, 3H), 2.44-2.33 (m, 1H), 2.21-2.10 (m, 1H).

Step 7. Synthesis of 1-benzyl-3-[2-(2-chloro-6-methylpyridin-3-yl)ethyl]-N-[(4-methoxyphenyl)methyl]pyrrolidin-3-amine (C46).

A mixture of C45 (40.0 g, 89.7 mmol) and platinum(IV) oxide (4.09 g, 18.0 mmol) in methanol (400 ml) was hydrogenated (60 ^psi (4.219 kg/cm2)) at 25°C for 3 hours. The reaction mixture was then filtered and the filtrate concentrated in vacuo to give C46 as a black oil. Yield: 4 0.5 g, estimated quantitative. LCMS m/z 450.3 [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ), characteristic peaks: δ 7.61 (d, J=7.7 Hz, 1H), 7.38-7.23 (m, 7H), 7.17 ( d, J=7.7 Hz, 1H), 6.88 (broad d, J=8.7 Hz, 2H), 3.78 (s, 3H), 3.64 (AB quartet, J _AB =12 ,0 Hz, Δ v _AB =21.6 Hz, 2H), 3.64 (s, 2H), 2.46 (s, 3H).

Step 8. Synthesis of 1'-benzyl-1-[(4-methoxyphenyl)methyl]-1-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] (C47) .

Mixture of C46 (400 g, 0.89 mol), palladium(II) acetate (9.97 g, 4 4.4 mmol), 2-dicyclohexylphosphino-2',6'-diisopropoxybiphenyl (RuPhos; 41.5 g, 88 .9 mmol) and sodium tert-butoxide (170 g, 1.77 mol) in 1,4-dioxane (4.0 L) were stirred at 90°C for 10 hours, then the reaction mixture was filtered and the filtrate was concentrated in vacuo. The residue was partitioned between ethyl acetate (2 L) and water (2 L) and the aqueous layer was extracted with ethyl acetate (1 L). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered, concentrated in vacuo and chromatographed on silica gel (gradient: 0% to 10% ethyl acetate in petroleum ether) to give C47 as a white solid. Yield: 195 g, 0.472 mol, 53%. LCMS m/z 414.3 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.38-7.21 (m, 5H, presumably; partially hidden by solvent peak), 7.17 (d, J=8.2 Hz, 2H), 7, 03 (d, J=7.2 Hz, 1H), 6.77 (d, J=8.2 Hz, 2H), 6.32 (d, J=7.3 Hz, 1H), 5.07- 4.92 (m, 2H), 3.77 (s, 3H), 3.54 (broad AB quartet, J _AB =13 Hz, Δ v _AB =40 Hz, 2H), 2.95 (d, J =10.2 Hz, 1H), 2.92-2.83 (m, 1H), 2.83-2.73 (m, 1H), 2.73-2.63 (m, 1H), 2, 43-2.31 (m, 1H), 2.29-2.08 (m, 2H), 2.23 (s, 3H), 2.03-1.73 (m, 3H).

Step 9. Synthesis of 1'-benzyl-1'-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] (C48).

Trifluoroacetic acid (523 g, 4.59 mol) was added to a 0°C solution of C47 (190 g, 0.459 mol) in dichloromethane (1.5 L) and the reaction mixture was stirred at 25°C for 3 hours. The mixture was then concentrated in vacuo; the residue was diluted with ethyl acetate (1.5 L) and washed with saturated aqueous sodium carbonate (1.0 L) and this aqueous layer was extracted with ethyl acetate (2 x 300 ml). The combined organic layers were concentrated in vacuo and purified by silica gel chromatography (gradient: 0% to 10% methanol in dichloromethane) to give C48 as a brown oil (17 9 g). This substance was used directly in the next step. LCMS m/z 294.3 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 9.1-8.3 (b.s, 1H), 7.41-7.35 (m, 2H), 7.35-7.28 (m, 2H), 7.28-7.22 (m, 2H, presumably; partially hidden by solvent peak), 6.35 (d, J=1.3 Hz, 1H), 3.72 (s, 2H), 2, 96-2.85 (m, 1H), 2.80-2.62 (m, 5H), 2.42 (s, 3H), 2.05 (ddd, J=13.1 8.1, 5, 0 Hz, 1H), 1.98-1.81 (m, 3H).

Step 10. Synthesis of tert-butyl-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-11-carboxylate (P17) and di-tert-butyl-7 '-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1,1'-dicarboxylate (P18).

A mixture of C48 (from previous step; 179 g, ≤0.459 mol), di-tert-butyl dicarbonate (199.7 g, 915 mmol) and palladium hydroxide (17.9 g, 127 mmol) in methanol (2.0 L ) and ethyl acetate (2.0 L) were hydrogenated at 55 ^psi (3.8 67 kg/cm ² ) and 25°C for 18 hours. The reaction mixture was then filtered through a pad of diatomaceous earth and the filtrate was concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 50% dichloromethane in ethyl acetate) gave P17 and P18, both as a white solid.

P17 - Yield: 101 g, 0.333 mol, 73% in 2 stages. LCMS m/z 304.3 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 7. 20 (d, J=7.3 Hz, 1H), 6.44 (d, J=7.4 Hz, 1H), 3.62-3 .44 (m, 2H), 3.37-3.3 (m, 2H, presumably; partially hidden by solvent peak), 2.84-2.66 (m, 2H), 2.27 (s, 3H), 2.05-1.92 (m, 2H), 1.92-1.76 (m, 2H), [1.48 (s) and 1.46 (s), total 9H].

P18 - Yield: 21.3 g, 52.8 mmol, 12% in 2 stages. LCMS m/z 404.3 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 7.49 (d, J=7.7 Hz, 1H), 7.02 (bd, J=7.7 Hz, 1H), [3, 85 (d, J=11.3 Hz) and 3.75 (d, J=11.2 Hz), total 1H), 3.62-3.47 (m, 2H), 3.40-3.24 (m, 1H, presumably; partially hidden by solvent peak), 2.89-2.73 (m, 2H), 2.54-2.27 (m, 1H), 2.44 (s, 3H), 2. 13-1.82 (m, 3H), 1.46 (s, 9H), [1.43 (s) and 1.43 (s), total 9H].

Receiving P19 and P20

tert-Butyl-(2S)-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P19) and tert-Butyl-(2R )-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P20)

Di-tert-butyl dicarbonate (3.97 g, 18.2 mmol) was added to a solution of C48 (4.45 g, 15.2 mmol) in a mixture of methanol (20 ml) and ethyl acetate (25 ml). After addition of palladium hydroxide on carbon (900 mg), the reaction mixture was hydrogenated at 80 ^psi (5.625 kg/cm ² ) for 18 hours, after which LCMS analysis showed complete conversion to P19/P20: LCMS m/z 304.2 [M+N] ⁺ . The reaction mixture was filtered and the filtrate was concentrated under reduced pressure; the residue was dissolved in ethyl acetate, washed successively with saturated sodium bicarbonate and saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo. Separation of enantiomer components was carried out by supercritical fluid chromatography {Column: Chiral Technologies Chiralpak IB, 30 × 250 mm, 5 μm; Mobile phase 9:1 carbon dioxide/[ethanol containing 0.2% (7 M ammonia in methanol)]; Flow rate: 80 ml/min; Back pressure: 100 bar). The first eluting enantiomer was indicated as P19 and the second eluting enantiomer as P20. Both were isolated as solids.

P19 - Yield: 1.60 g, 5.27 mmol, 35%. Retention time: 3.75 minutes [Analytical conditions. Column: Chiral Technologies Chiralpak IB, 4.6 × 250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: ethanol containing 0.2% (7 M ammonia in methanol); Gradient: 5% B for 1 minute, then 5% to 60% B over 8 minutes; Flow rate: 3.0 ml/min; Back pressure: 120 bar].

P20 - Yield: 1.50 g, 4.94 mmol, 32%. Retention time: 3.96 minutes (Analytical conditions identical to those used for P19).

The reported absolute stereochemistry was assigned based on the conversion of this batch of P19 to P23 in Alternate Preparation (#1) of P23 below. The absolute configuration of P23 was established by its use in synthesis 14, which was analyzed by single crystal X-ray diffraction (see below).

Getting P21

Di-tert-butyl-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1,1'-dicarboxylate (P21)

To a 0°C solution of P18 (20 g, 50 mmol) in dichloromethane (200 ml) was added 1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione (7.09 g, 2 4.8 mmol) in six in portions for 3 0 minutes. The reaction mixture was stirred at 0°C for 1 hour, then the mixture was treated with saturated aqueous sodium sulfite (2 00 ml) and extracted with dichloromethane (3 x 100 ml). The combined organic layers were washed with saturated aqueous sodium bicarbonate, dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 40% ethyl acetate in petroleum ether) gave P21 as a white solid. Yield: 22.8 g, 47.2 mmol, 94%. LCMS m/z 384.1 (observed bromine isotopic pattern) {[M-(2-methylprop-1-ene and CO ₂ )]+H} ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.51 (bbs, 1H), [3.89 (d, J=11.0 Hz) and 3.73 (d, J=11.0 Hz ), total 1H], 3.65-3.51 (m, 1H), 3.46 (d, J=11.0 Hz, 1H), 3.38-3.26 (m, 1H), [2 .87-2.56 (m) and 2.15-1.70 (m), total 6H], 2.57 (s, 3H), [1.46 (s) and 1.45 (s), total 18Н].

Getting P22

tert-Butyl-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P22)

1,3-Dibromo-5,5-dimethylimidazolidine-2,4-dione (2.47 g, 8.64 mmol) was added portionwise over 20 minutes to a 0°C solution of P17 (5.25 g, 17. 3 mmol) in dichloromethane (69 ml). After stirring the reaction mixture at 0°C for 4-5 minutes, LCMS analysis showed conversion to P22: LCMS m/z 384.3 (observed bromine isotope pattern) [M+H] ⁺ . After 1 hour at 0°C, the reaction mixture was treated with saturated aqueous sodium sulfite (100 ml) and the mixture was extracted with dichloromethane. The organic layer was washed successively with saturated aqueous sodium bicarbonate and saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo to give P22 as a solid. Yield: 6.60 g, 17.3 mmol, quantitative. ¹ H NMR (400 MHz, methanol-d ₄ ) δ 7.40 (b.s, 1H), 3.61-3.43 (m, 2H), 3.37-3.3 (m, 2H, presumably ; almost completely hidden by the water peak), 2.85-2.67 (m, 2H), 2.37 (s, 3H), 2.06-1.92 (m, 2H), 1.92-1.75 (m, 2H), [1.47 (s) and 1.46 (s), total 9H].

Receiving P23 and P24

tert-Butyl-(2S)-6-bromo-1-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P23) and tert- butyl-(2R)-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P24)

1,3-Dibromo-5,5-dimethylimidazolidine-2,4-dione (5.65 g, 19.8 mmol) was added portionwise to a 0°C solution of P17 (10.0 g, 32.9 mmol) in dichloromethane (150 ml) and the reaction mixture was stirred at 0°C-5°C for 1 hour, after which LCMS analysis showed that bromination had occurred: LCMS m/z 382.3 [M+H] ⁺ . A saturated aqueous sodium sulfite solution (20 ml) was added, followed by water (50 ml); the resulting aqueous layer was extracted with dichloromethane (2 x 50 ml). The combined organic layers were washed with saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo; chromatography on silica gel (gradient: 0% to 100% ethyl acetate in heptane) gave a racemic mixture of P23 and P24 as a light yellow foam (11.8 g). This material was combined with the product of a similar reaction carried out using P17 (7.40 g, 24.4 mmol) to give a light yellow foam (20.9 g, 54.6 mmol, 95% combined yield), and it was separated into its constituent enantiomers by supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ, 50 × 250 mm, 5 μm; Mobile phase 4:1 carbon dioxide/(1:1 methanol/acetonitrile); Flow rate: 250 ml/min; Back pressure: 120 bar]. The first eluting enantiomer was indicated as P23, and the second eluting enantiomer was indicated as P24.

The indicated absolute stereochemistry was assigned based on the conversion of this batch of P23 to P28 (see Preparation of P28) and then to Example 14; The absolute stereochemistry of 14 was determined by single crystal X-ray diffraction (see below).

P23 isolated as a yellow oil which solidified on standing - Combined yield: 9.37 g, 24.5 mmol, 43%. ^1H NMR (400 MHz, DMSO- _d6 ) δ 7.37 (s, 1H), 7.02-6.96 (m, 1H), [3.55-3.40 (m), 3.36 -3.26 (m, presumably; partially hidden by the peak of water) and 3.24-3.13 (m), total 4H], 2.75-2.55 (m, 2H), 2.31 (s, 3H ), 1.95-1.78 (m, 2H), 1.76-1.60 (m, 2H), [1.40 (s) and 1.38 (s), total 9H]. Retention time: 4.01 min [Analytical conditions. Column: Chiral Technologies Chiralcel OJ-H, 4.6 × 250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: methanol containing 0.2% (7 M ammonia in methanol); Gradient: 5% B for 1 minute, then 5% to 60% B over 8 minutes; Flow rate: 3.0 ml/min; Back pressure: 120 bar].

P24 - Combined yield: 11.8 g, which contained ethanol; adjusted estimate: 28.4 mmol, 50%. ^1H NMR (400 MHz, DMSO- _d6 ), characteristic peaks: δ 7.37 (s, 1H), 7.01-6.96 (m, 1H), 2.75-2.55 (m, 2H ), 2.31 (s, 3H), 1.95-1.78 (m, 2H), 1.76-1.60 (m, 2H), [1.40 (s) and 1.38 (s ), total 9H]. Retention time: 4.32 min (Analytical conditions identical to those used for P23).

Alternative Receipt (#1) P23

tert-Butyl-(2S)-6-bromo-7-methyl-36-4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P23)

1,3-Dibromo-5,5-dimethylimidazolidine-2,4-dione (625 mg, 2.19 mmol) was added in portions to 0°C solution P19 (substance from Preparations P19 and P20; 1.10 g, 3. 63 mmol) in dichloromethane (20 ml). After stirring the reaction mixture at room temperature for 1 hour, LCMS analysis showed conversion to P23: LCMS m/z 384.2 (observed bromine isotopic pattern) [M+H] ⁺ . Saturated aqueous sodium sulfite was then added and the resulting mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dried over magnesium sulfate, filtered, concentrated in vacuo and purified by silica gel chromatography (gradient: 10% to 40% ethyl acetate in heptane) to give P23 as a white solid. Yield: 1.25 g, 3.27 mmol, 90%. ^1H NMR (400 MHz, chloroform-d) δ 7.33 (s, 1H), 5.15-5.01 (br.s, 1H), 3.59-3.45 (m, 2H), 3 .43-3.25 (m, 2H), 2.81-2.66 (m, 2H), 2.43 (s, 3H), 2.01-1.74 (m, 4H), 1.48 -1.43 (b.s, 9H).

The absolute stereochemistry of this sample P23 was assigned as indicated by comparison with their Preparation samples P23 and P24:

Retention time of P23 from Alternative Preparation (#1) P23: 4.08 min

Retention time of racemic mixture P23 and P24: 4.07 and 4.36 min.

Retention time of P23 from Preparation of P23 and P24: 4.01 min

Retention time of P24 from Preparation of P23 and P24: 4.32 min

These four analyzes were performed using the same analytical method: [Column: Chiral Technologies Chiralcel OJ-H, 4.6 x 100 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: methanol containing 0.2% (7 M ammonia in methanol); Gradient: 5% B for 1 minute, then 5% to 60% B over 8 minutes; Flow rate: 3.0 ml/min].

Alternate Receipt (#2) P23

tert-Butyl-(2S)-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P23)

Step 1. Synthesis of (2-chloro-6-methylpyridin-3-yl)methanol (C49).

A solution of sodium bis(2-methoxyethoxy)aluminum hydride (70%; 1.05 kg, 2.5 eq.) was added to a solution, at -5°C to 5°C, of 2-chloro-6-methylpyridine-3-carboxylic acid. acid (250 g, 1.4 6 mol) in toluene (2.5 l). After stirring the reaction mixture at -5°C to 5°C for 19 hours, the mixture was treated with a solution of sodium hydroxide (145.7 g, 3.642 mol, 2.50 eq.) in water (1.25 L), maintaining the internal temperature below 0°C to 10°C. The resulting mixture was then heated to 25°C; after 15 minutes, the aqueous layer was extracted with propan-2-yl acetate (2 x 1.25 L). These two extracts were combined with a toluene layer and filtered through silica gel (125 g). The filter cake was washed with propan-2-yl acetate (125 ml) and the combined filtrates were concentrated to 8 volumes at 40°C-45°C to give C49 as a solution in toluene (1.602 kg, 11.2% C49 by weight); the bulk of this solution was used in the next step. Estimated yield: 179.4 g, 1.138 mol, 78%. ¹ H NMR (400 MHz, DMSO-d ₆ ) δ 7.81 (d, J=7.8 Hz, 1H), 7.29 (d, J=7.7 Hz, 1H), 5.48 (t , J=5.6 Hz, 1H), 4.50 (d, J=5.6 Hz, 2H), 2.43 (s, 3H).

Step 2. Synthesis of (2-chloro-6-methylpyridin-3-yl)methylmethanesulfonate (C50).

Triethylamine (134.2 g, 1.32 6 mol) was added to a solution of C49 in toluene (from the previous step; 1.537 kg containing 11.2% C49, 172.1 g, 1.09 mol). The solution was cooled to -5°C to 5°C and then treated dropwise with methanesulfonyl chloride (128.5 g, 1.122 mol), maintaining the internal temperature at -5°C to 5°C. After stirring the reaction mixture at this temperature for 2 hours, triethylamine (22.7 g, 0.224 mol) was added again, followed by dropwise addition of methanesulfonyl chloride (25.7 g, 0.224 mol). Stirring was continued at -5°C-5°C for 1 hour, then the reaction mixture was treated with water (805 ml), maintaining the internal temperature below 25°C, and then stirred for 15 minutes at 25°C. The organic layer was washed with water (805 ml) and concentrated to give C50 as a solution in toluene (861 g). This solution was used directly in the next step. ¹ H NMR (400 MHz, DMSO-d ₆ ) δ 7.92 (d, J=7.7 Hz, 1H), 7.36 (d, J=1.7 Hz, 1H), 5.30 (s , 2H), 3.29 (s, 3H), 2.48 (s, 3H).

Step 3. Synthesis of 2-chloro-3-(methyl)-6-methylpyridine (C51).

Sodium iodide (230 g, 1.53 mol) was dissolved in acetone (1.13 kg) at 25°C; to this solution was added a solution of C50 in toluene (from the previous step; 861 g, ≤1.09 mol C50). After stirring the reaction mixture at 25°C for 1 hour, a solution of sodium metabisulfite (57.86 g, 0.3044 mol) in water (1.45 L) was added and stirring was continued for 30 minutes. The organic layer was separated, diluted with toluene (417 ml) and concentrated to 5 volumes to give C51 as a solution in toluene (1.110 kg, 22.93% C51 by weight). This solution was used directly in the next step. Estimated yield: 254.5 g, 0.9514 mol, 87% in 2 stages. ¹ H NMR (400 MHz, DMSO-d ₆ ) δ 7.90 (d, J=7.7 Hz, 1H), 7.26 (d, J=7.8 Hz, 1H), 4.55 (s , 2H), 2.41 (s, 3H).

Step 4. Synthesis of [(2-chloro-6-methylpyridin-3-yl)methyl](triphenyl)phosphonium iodide (C52).

A solution of C51 in toluene (from the previous step; 1.110 kg, 22.93% C51 by weight, 254.5 g, 0.9514 mol) was diluted with acetonitrile (1.29 L) and treated with triphenylphosphine (262 g, 0.999 mol). After stirring the reaction mixture for 4 hours at 25°C, the mixture was cooled to 10°C, stirred at this temperature for 16 hours and filtered. The filter cake was washed with toluene (255 ml) and dried at 45°C for 4 hours to obtain C52 as a solid. Yield: 412.6 g, 0.7788 mol, 56% in 4 steps. Purity: 99.7% by HPLC. ^1H NMR (400 MHz, DMSO- _d6 ) δ 7.97-7.90 (m, 3H), 7.80-7.71 (m, 8H), 7.71-7.66 (m, 4H ), 7.44 (dd, J=1.8, 2.4 Hz, 1H), 7.20 (d, J=1.8 Hz, 1H), 5.15 (d, J _HP =15.0 Hz, 2H), 2.40 (d, J=2.4 Hz, 3H).

Step 5. Synthesis of diethyl 1-benzylpyrrolidine-3,3-dicarboxylate (C53).

A solution of ethyl 1-benzylpyrrolidine-3-carboxylate (700 g, 3.00 mol) in tetrahydrofuran (4.20 L) was added dropwise over 5 hours to the solution, at a temperature of -80°C to -70°C, lithium diisopropylamide (2.0 M, 2.40 L, 4.80 mol). Stirring was continued at -80°C to -70°C for 2 hours, then ethyl chloroformate (423.5 g, 3.90 mol) was added over 3 hours, maintaining the reaction temperature at -80°C to -70° WITH. After stirring the reaction mixture for 2 hours at a temperature of -80°C to -70°C, the temperature was brought to a temperature of -50°C to -40°C and the reaction mixture was quenched by adding a solution of acetic acid (288 g, 4.80 mol ) in tetrahydrofuran (1.40 l), maintaining the temperature from -50°C to -40°C. The resulting mixture was heated to 15°C-25°C and partitioned between water (3.50 L) and 2-methyltetrahydrofuran (7.0 L). After stirring the mixture for 30 minutes at 15°C-25°C, the aqueous layer was extracted with 2-methyltetrahydrofuran (7.0 L) and the combined organic layers were washed with a solution of acetic acid (288 g, 4.80 mol) in water (4. 2 l) and then with an aqueous solution of sodium sulfate (10%; 2 × 3.50 kg). The organic layers were concentrated in vacuo to 2-3 volumes, maintaining the temperature below 50°C. Ethanol (4.90 L, 7 volumes) was added and the solution was again concentrated in vacuo to 2-3 volumes, maintaining the temperature below 50°C. This ethanol addition/concentration was carried out a total of three times, using 2.80 L of ethanol for the final cycle, followed by concentration to 4-5 volumes. This gave C53 as a solution in ethanol (3.148 kg, 24.23% C53 by weight). Part of this solution was used in the next step. Calculated yield: 762.8 g, 2.498 mol, 83%. ¹ H NMR (400 MHz, DMSO-d ₆ ) δ 7.35-7.20 (m, 5H), 4.12 (q.v., J=7.1 Hz, 4H), 3.57 (s, 2H ), 2.90 (s, 2H), 2.55 (t, J=6.9 Hz, 2H), 2.29 (t, J=6.8 Hz, 2H), 1.14 (t, J =1.1 Hz, 6H).

Step 6. Synthesis of diethylpyrrolidine-3,3-dicarboxylate, L-tartrate salt (C54).

Ethanol (720 ml, 6 volumes) was added to a solution of C53 (120 g, 0.393 mol) in ethanol (from the previous step; approximately 500 ml). After adding wet palladium-carbon (10%; 12 g), the reaction vessel was evacuated and charged with argon three times, and then evacuated and charged with hydrogen three times. Hydrogenation was then carried out ^at 40-50 ^psi and 40°C-50°C for 24 hours. The resulting mixture was filtered through diatomaceous earth (50 g); the filter cake was washed with ethanol (240 ml, 2 volumes) and the combined filtrates were concentrated in vacuo to 2.5-3.5 volumes, maintaining the temperature at 45°C or lower. This solution was added, over 2 hours, to a 40°C-50°C solution of L-tartaric acid (16.1 g, 0.511 mol) in water (85 ml, 0.7 volumes) and ethanol (465 ml). After stirring the mixture at 40°C-50°C for 1 hour, C54 seed (0.4 g; see below) was added at 45°C. The mixture was cooled to 10°C for 6 hours and then stirred at 10°C for 4 hours; filtration yielded a filter cake, which was washed with ethanol (2 volumes) and dried at 40°C for 20 hours to obtain C54 as a solid. Yield: 127.4 g, 0.3487 mol, 89%. HPLC purity: 99.1%. ¹ H NMR (400 MHz, DMSO-d ₆ ) δ 4.16 (sq., J=7.1 Hz, 4H), 4.03 (s, 2H), 3.49 (s, 2H), 3, 08 (t, J=7.1 Hz, 2H), 2.32 (t, J=7.1 Hz, 2H), 1.18 (t, J=7.1 Hz, 6H).

The seed material used above was obtained from another run of the same C54 synthesis, in which the C54 solid formed directly upon cooling.

Step 7. Synthesis of 1-tert-butyl-3,3-diethylpyrrolidine-1,3,3-tricarboxylate (C55).

Di-tert-butyl dicarbonate (19.7 g, 90.3 mmol) was added dropwise to a 20°C-30°C mixture of C54 (88.12 g, 0.2412 mol) and triethylamine (73.33 g, 0. 7247 mol) in dichloromethane (881 ml, 10 volumes). Additional di-tert-butyl dicarbonate (19.2 g, 88.0 mmol and 19.3 g, 88.4 mmol) was added dropwise for periodic HPLC analysis. After stirring the reaction mixture at 20°C-30°C for 18 hours, the pH was adjusted to 7 by adding hydrochloric acid (1 M; 309 g) and stirring was continued for 15 minutes. The organic layer was stirred with aqueous sodium sulfate (10%; 485.30 g) at 20°C-30°C for 15 minutes and then the organic layer was concentrated in vacuo to 1-2 volumes while maintaining the temperature below 40°C. Dimethyl sulfoxide (71.7 g) was added to give C55 as a solution in dimethyl sulfoxide (154.2 g, 48.9% C55 by weight). The bulk of this substance was used in the next stage. Estimated yield: 75.4 g, 0.239 mol, 99%. ¹ H NMR (400 MHz, DMSO-d ₆ ) δ 4.16 (sq., J=1.1 Hz, 4H), 3.67 (b.s, 2H), 3.34-3.26 (m , 2H), 2.37-2.28 (m, 2H), 1.39 (s, 9H), 1.17 (bt, J=1.1 Hz, 6H).

Step 8. Synthesis of (3PJ -1-(tert-butoxycarbonyl)-3-(ethoxycarbonyl)pyrrolidine-3-carboxylic acid (C56).

ECS-Esterase 03 enzyme [Bacillus stearothermophilus, recombinant from Escherichia coli, (EC 3.1.1.1); 0.540 g] was added to phosphate buffer (0.1 M; pH=6.92, 580 ml, 8.2 volumes) at 20°C-30°C. A solution of C55 (72.2 g, 0.229 mol) in dimethyl sulfoxide (from previous step; approximately 148 g) was added; Additional dimethyl sulfoxide (9 ml) was used to rinse the original vessel and was also added to the reaction mixture. The initial pH value of the reaction was 7.08; after stirring at 20°C-30°C for 1 hour, the pH decreased to 6.58. A pH autotitrator was used to maintain the pH at 7.5 by adding aqueous sodium hydroxide (2 M; 121 mL, 0.242 mol) for 24 hours. Hydrochloric acid (6 M; 52 mL, 0.312 mol) was added to adjust the pH to 2.39; then ethyl acetate (435 ml, 6.0 volumes) was added and the mixture was stirred for 30 minutes at 20°C-30°C. Filtration through diatomaceous earth (18.0 g) gave a filter cake, which was washed with ethyl acetate (2 x 7 5 ml). The combined filtrates were stirred at 20°C-30°C for 30 minutes and then the aqueous layer was stirred with ethyl acetate (217 ml, 3.0 volume) for 30 minutes. The combined organic layers were washed twice with water (360 ml, 5.0 volumes) with stirring for 30 minutes. The resulting solution was concentrated in vacuo to 1-2 volumes, maintaining the temperature below 40°C, then diluted with toluene (360 ml); this concentration/dilute procedure was carried out a total of three times to obtain C56 as a solution in toluene (418.3 g, 15.67% C56 by weight). Calculated yield: 65.6 g, 0.228 mol, quantitative. ^1H NMR (400 MHz, chloroform-d) δ 7.99 (very broad s, 1H), 4.22 (sq., J=1.1 Hz, 2H), [3.88 (broad s) and 3.83 (broad s), total 2H), 3.51-3.38 (m, 2H), 2.41 (t, J=7.1 Hz, 2H), 1.44 (s, 9H) , 1.26 (bt, J=1 Hz, 3H).

Step 9. Synthesis of 1-tert-butyl-3-ethyl-(3S)-3-{[(benzyloxy)carbonyl]amino}pyrrolidine-1,3-dicarboxylate (C57).

Toluene (17 0 ml, 1.2 volumes) was added to a solution of C56 in toluene (3.8 volumes, containing 2 8.9% by weight C56, 14 6.4 g, 0.5096 mol); the solution was heated to 80°C-90°C. To this was slowly added, over 2 hours, a mixture of triethylamine (77.4 g, 0.765 mol) and diphenylphosphorazidate (140.3 g, 0.5098 mol) in toluene (732 ml, 5 volumes). The reaction mixture was stirred at 80°C-90°C for 3 hours, then the mixture was cooled to 50°C and treated dropwise over 2 hours with a solution of benzyl alcohol (55.12 g, 0.5097 mol) in toluene ( 290 ml, 2 volumes). After stirring the reaction mixture at 100°C for 16 hours, the mixture was cooled to 15°C-25°C and partitioned between toluene (1.46 L, 10 volumes) and water (2.20 L, 15 volumes) with stirring for 30 minutes. The organic layer was washed successively with aqueous potassium carbonate (10%; 3 x 1.46 L) and water (2 x 750 mL). The mixture was then concentrated in vacuo to 1-2 volumes, maintaining the temperature below 50°C, and diluted with tetrahydrofuran (1.0 L); This concentration/dilute procedure was carried out a total of three times, then the mixture was concentrated in vacuo to 4-5 volumes, maintaining the temperature below 50°C. This gave C57 as a solution in tetrahydrofuran (595.8 g, 19.14% C57 by weight). Calculated yield: 114 g, 0.290 mol, 57%. ^1H NMR (400 MHz, chloroform-d) δ 7.40-7.28 (m, 5H), 5.25 (very broad s, 1H), 5.10 (brest s, 2H), 4.28 -4.12 (m, 2H), 3.91-3.76 (m, 1H), 3.71-3.38 (m, 3H), 2.54-2.15 (m, 2H), 1 .45 (s, 9H), 1.27-1.16 (m, 3H).

Step 10. Synthesis of tert-butyl-(3S)-3-{[(benzyloxy)carbonyl]amino}-3-(hydroxymethyl)pyrrolidine-1-carboxylate (C58).

A solution of lithium borohydride in tetrahydrofuran (2 M; 511 ml, 1.02 mol) was added over 2 hours to a 0°C-10°C solution of C57 in tetrahydrofuran (835.6 g, containing 19.20% C57 by weight, 160 .4 g, 0.4 087 mol). After stirring the reaction mixture at 0°C to 10°C for 15 hours, the mixture was cooled to a temperature of -5°C to 5°C and treated dropwise with hydrochloric acid (0.5 M; 2.08 L, 1.04 mol , 13 volumes) to pH 7. The mixture was then heated to 20°C-30°C, diluted with ethyl acetate (1.60 L, 10 volumes) and stirred for 10 minutes, then the organic layer was concentrated in vacuo to 2-3 volumes, maintaining the temperature at 50°C or lower. The resulting mixture was diluted with acetonitrile (880 ml) and concentrated in vacuo to 2-3 volumes, maintaining the temperature at 50°C or lower; this dilution/concentration procedure was performed a total of three times. The mixture was then heated to 40°C-50°C and stirred for 1 hour, then the mixture was cooled over 4 hours to 15°C-25°C. Water (164 ml) was added dropwise over 2 hours at 15°C-25°C and the mixture was stirred at 15°C-25°C for 12 hours. The resulting solid was collected by filtration and dried under vacuum for 40 hours at a temperature of 50°C or lower to obtain C58 as a solid. Yield: 123.2 g, 0.3516 mol, 86%. HPLC purity: 99.8%. ^1H NMR (400 MHz, DMSO-d ₆ ) δ 7.40-7.27 (m, 5H), 4.99 (s, 2H), 4.93 (t, J=5.8 Hz, 1H) , 3.58-3.45 (m, 3H), 3.31-3.21 (m, 3H), 2.10-1.85 (m, 2H), 1.38 (s, 9H).

Step 11. Synthesis of tert-butyl-(3S)-3-{[(benzyloxy)carbonyl]amino}-3-formylpyrrolidine-1-carboxylate (C59).

A solution of C58 (125 g, 0.357 mol) and dimethyl sulfoxide (144.5 g, 1.84 9 mol) in dichloromethane (2.02 L) was stirred for 2 hours at 35°C-45°C; Karl Fischer analysis showed a water content of 0.029%. The solution was concentrated in vacuo to 3-4 volumes at 35°C-45°C and then diluted with dichloromethane (1.80 L). Another Karl Fischer analysis showed a water content of 0.034%. The solution was concentrated in vacuo at 35°C-45°C to 6-7 volumes, then triethylamine (112.3 g, 1.110 mol) was added at 20°C-30°C and the reaction mixture was cooled to -5°C to 0°C and stirred at this temperature for 15 minutes. Sulfur trioxide pyridine complex (141.3 g, 0.8878 mol) was added in portions over 2 hours; stirring was then continued at -5°C to 0°C for 16 hours, after which the reaction mixture was heated to 35°C-45°C and concentrated to 2-3 volumes. The mixture was cooled to 20°C-30°C, then partitioned between ethyl acetate (945 ml) and water (675 ml) and the aqueous layer was extracted with ethyl acetate (675 ml). The combined organic layers were washed successively with hydrochloric acid (1 M; 675 ml), water (675 ml) and saturated aqueous sodium bicarbonate (675 ml), then concentrated to dryness at 30°C-40°C to obtain C59 as an oil. Yield: 118.7 g, 0.3407 mol, 95%. HPLC purity: 91.2%. ^1H NMR (400 MHz, chloroform-d) δ 9.59 (s, 1H), 7.42-7.29 (m, 5H), 5.39 (br s, 1H), 5.12 (s , 2H), 3.85-3.70 (m, 1H), 3.63-3.43 (m, 3H), 2.44-2.04 (m, 2H), 1.45 (s, 9H ).

Step 12. Synthesis of tert-butyl-(3R)-3-{[(benzyloxy)carbonyl]amino}-3-[(E)-2-(2-chloro-6-methylpyridin-3-yl)ethenyl]pyrrolidin- 1-carboxylate (C60) and tert-butyl-(3R)-3-{[(benzyloxy)carbonyl]amino}-3-[(Z)-2-(2-chloro-6-methylpyridin-3-yl)ethenyl ]pyrrolidine-1-carboxylate (C61).

A mixture of C59 (237.1 g, 0.6805 mol) and C52 (393.6 g, 0.7429 mol) in dimethyl sulfoxide (2.40 L, 10 volumes) was treated with potassium carbonate (188.7 g, 1.365 mol) and heated at 60°C for 2 hours. Propan-2-yl acetate (1.54 L, 6.5 volumes), water (6.40 L, 27 volumes), and aqueous sodium sulfate (10%; 710 mL, 3.0 volumes) were then added and the mixture was stirred for 20 minutes at 25°C. The organic layer was washed three times with aqueous sodium sulfate (10%; 1.30 L, 5.5 volumes) with each mixture stirred for 20 minutes before separation. The mixture was then washed with aqueous sodium bicarbonate (7%; 1.30 L, 5.5 volumes) in the same manner and concentrated in vacuo to 1-2 volumes at 50°C or lower. Propan-2-yl acetate (1.06 L) was added and the mixture was concentrated in vacuo to 1-2 volumes at 50° C. or below. Propan-2-yl acetate (480 ml) was added followed by dropwise addition of methylcyclohexane (1.66 L) at 20°C-30°C. The resulting mixture was stirred at 20°C to 30°C for 1 hour, then the mixture was cooled to a temperature of -15°C to -5°C and stirred at this temperature for 16 hours. Filtration of the suspension was carried out at -15°C to -5°C and the filter cake was washed with a mixture of propan-2-yl acetate and methylcyclohexane (ratio 3:7, 710 ml) at a temperature of -15°C to -5°C. The combined filtrates were concentrated in vacuo, diluted with methylcyclohexane (20 volumes) and chromatographed on silica gel (gradient: 14% to 25% ethyl acetate in methylcyclohexane) to give a mixture of C60 and C61 as an oil. This substance was believed to consist of 3-4 isomers/rotamers based on ¹ H NMR analysis. Yield: 268.1 g, 0.5680 mol, 83%. HPLC purity: ≥99.7%. ¹ H NMR (400 MHz, DMSO-d ₆ ), characteristic peaks: δ [8.00 (d, J=1.9 Hz) and 7.59 (d, J=1.6 Hz), total 1H], [7.85 (s) and 7.41 (s), total 1H], [7.38-7.25 (m), 7.22 (br.d, J=7.2 Hz) and 7.16 (d, J=1.1 Hz), total 6H], [6.62 (d, component of AB quartet, J=16.1 Hz) and 6.34 (d, J=12.3 Hz), total 1H ], [6.49 (broadening d, AB quartet component, J=16.0 Hz), 5.88 (d, J=12.3 Hz) and 5.87 (d, J=12.3 Hz) , total 1H], [5.04 (AV quartet, J _AB =12.7 Hz, Δν _AB =16.4 Hz), 4.74 (d, component of the AB quartet, J=12.4 Hz) and 4, 70-4.62 (m), total 2H], 3.83-3.68 (m, 1H), 3.32-3.16 (m, 3H), [2.43 (s) and 2.36 (s), total 3H], 2.27-2.12 (m, 1H), 2.00-1.85 (m, 1H), [1.40 (s), 1.39 (s), 1 .37 (s) and 1.34 (s), total 9H].

Step 13. Synthesis of tert-butyl-(3S)-3-{[(benzyloxy)carbonyl]amino}-3-[2-(2-chloro-6-methylpyridin-3-yl)ethyl]pyrrolidine-1-carboxylate ( C62).

The reaction vessel containing a mixture of C60 and C61 (283.0 g, 0.5996 mol) and rhodium on alumina (5%; 14.15 g) in methanol (1.98 L) was evacuated and charged with argon three times, then evacuated and loaded with hydrogen three times. Hydrogenation was then carried out for 40 hours at 30-40 ^psi (2.109-2.812 kg/cm ² ) and 20°C-25°C. The reaction mixture was filtered through diatomaceous earth (424 g), the filter cake was washed with methanol (5 volumes); the combined filtrates were concentrated in vacuo at 35°C-45°C. The resulting substance was treated with toluene (5 volumes) and concentrated in vacuum at 50°C-60°C; this toluene addition/concentration procedure was carried out a total of three times to obtain C62. Yield: 254.4 g, 0.5367 mol, 90%. HPLC purity: 97.1%. ¹ H NMR (400 MHz, chloroform-d) δ 7.41-7.28 (m, 6H), 6.99 (bd, J=7.6 Hz, 1H), 5.06 (s, 2H ), 4.91-4.79 (m, 1H), 3.62 (d, J=11.7 Hz, 1H), 3.57-3.36 (m, 2H), 3.36-3, 26 (m, 1H), 2.74-2.55 (m, 2H), 2.48 (s, 3H), [2.48-2.40 (m), 2.39-2.07 (m ) and 2.05-1.82 (m), total 4H], 1.45 (broad s, 9H).

Step 14. Synthesis of tert-butyl-(2S)-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P19).

A solution of C62 in toluene (947.73 g, containing 19% C62 by weight, 180 g, 0.380 mol) was diluted with toluene (1.17 L, 6.5 volumes) and treated sequentially with 2-dicyclohexylphosphino-2',6'-diisopropoxybiphenyl (RuPhos; 35.44 g, 75.95 mmol) and potassium phosphate (145.1 g, 0.6836 mol). The resulting mixture was purged with nitrogen three times, then tris(dibenzylideneacetone)dipalladium(0) (34.78 g, 37.98 mmol) was added and three additional nitrogen purges were performed. The reaction mixture was stirred for 24 hours at 75°C-85°C. Potassium phosphate (16.2 g, 0.117 mol) was added and stirring was continued at 75°C-85°C for an additional 16 hours. The reaction mixture was cooled to 20°C-30°C, then potassium tert-butoxide (76.7 g, 0.684 mol) was added and the reaction mixture was stirred for 2 hours at 75°C-85°C. The mixture was then cooled and partitioned between water (2.25 L) and ethyl acetate (2.25 L); after stirring for 30 minutes at 20°C-30°C, the mixture was filtered through diatomaceous earth (180 g) and the filter cake was washed with ethyl acetate (1.80 L). The organic layer of the combined filtrates was washed successively with water (2×2.25 L) and an aqueous solution of sodium sulfate (10%; 2.25 L), then extracted three times with an aqueous solution of citric acid (0.5 M; 1.072 kg, 1.4 eq.). The combined citric acid layers were washed with ethyl acetate (2 x 1.07 L), then adjusted to pH 7 by adding aqueous sodium hydroxide (30%; 596 g) at 20°C-30°C. Extraction of the aqueous layer with ethyl acetate (3 x 1.07 L) and subsequent addition of a combination of these three organic layers gave P19 as a solution in ethyl acetate (3.218 kg, 2.7% P19 by weight); the bulk of this substance was used in the next stage. Estimated yield: 86.9 g, 0.286 mol, 75%. HPLC purity: 98.9%. ^1H NMR (400 MHz, chloroform-d) δ 7.11 (d, J=7.3 Hz, 1H), 6.41 (d, J=7.4 Hz, 1H), 4.90 (br. s, 1H), 3.59-3.43 (m, 2H), [3.40 (d, AB quartet component, J=11.1 Hz) and 3.36-3.25 (m), total 2H ], 2.80-2.65 (m, 2H), 2.31 (s, 3H), 2.00-1.75 (m, 4H), [1.45 (s) and 1.44 (s ), total 9H].

Step 15. Synthesis of tert-butyl-(2S)-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylta( P23).

1,3-Dibromo-5,5-dimethylimidazolidine-2,4-dione (45.60 g, 0.1595 mol) was added to a 0°C-5°C solution of P19 in ethyl acetate (from the previous step; 2986 g containing 2.7% P19, 80.6 g, 0.266 mol). After stirring the reaction mixture for 1 hour at 0°C-5°C, the mixture was quenched by adding an aqueous solution of sodium sulfite (10%; 203 g) and water (456 ml) and the resulting mixture was stirred at 10°C-20°C for 20 minutes. The aqueous layer was extracted twice with ethyl acetate (415 ml, 5.1 volumes) with stirring at 10°C-20°C for 20 minutes; the combined organic layers were then stirred for 20 minutes with aqueous sodium sulfate (10%; 456 g). The organic layer was concentrated to 1-2 volumes in vacuo at below 50°C, then diluted with methanol (480 ml, 6 volumes). This concentration/dilute procedure was carried out a total of three times and the final solution was concentrated in vacuo, below 50°C, to 5-6 volumes. The resulting solution was cooled to 15°C-25°C and water (415 ml) was slowly added over 2 hours at 15°C-25°C and then stirred for 14 hours at 15°C-25°C. Filtration yielded a filter cake, which was washed with a mixture of methanol and water (1:1, 2×200 ml) and then dried in vacuum at 45°C for 48 hours to obtain P23 as a solid. Yield: 99.50 g, 0.2603 mol, 98%. HPLC purity: 99.7%. LCMS m/z 384.1 (observed bromine isotopic pattern) [M+H] ⁺ . ^1H NMR (400 MHz, DMSO- _d6 ) δ 7.37 (s, 1H), 7.03-6.97 (m, 1H), 3.55-3.43 (m, 1H), 3, 3-3.25 (m, 1H, presumably; partially hidden by the water peak), 3.24-3.13 (m, 2H), 2.75-2.55 (m, 2H), 2.30 (s, 3H), 1.95-1.77 (m, 2H), 1.76-1.59 (m, 2H), [1.40 (s) and 1.38 (s), total 9H].

Acquisition of X-ray powder diffraction (PXRD) data for crystalline P23

Sample P23 [obtained as described in Alternate Preparation Step 15 (#2) above] was submitted for powder X-ray diffraction (PXRD) analysis and was found to be a crystalline substance.

Powder X-ray diffraction analysis was carried out using a Bruker AXS D8 Endeavor diffractometer equipped with a copper radiation source (Cu). The divergence slit was set to constant illumination of 15 mm. Diffracted radiation was detected by a PSD-Lynx Eye detector with the PSD detector slit set at 4.123 degrees. The X-ray tube voltage and current were set to 40 kV and 4 0 mA, respectively. In addition, an energy dispersive detector and a nickel filter were used. Data were collected in a Theta-Theta goniometer at Cu wavelengths from 3.0 to 40.0 degrees 2-theta using a step size of 0.0100 degrees and a step time of 1.0 seconds. The anti-scatter screen was installed at a fixed distance of 1.5 mm. Samples were prepared by placing them in a low-background silicone sample holder and rotating them at 15 rpm during collection. Data were collected using Bruker DIFFRAC Plus software and analysis was performed using EVA diffract plus software. The PXRD data file was not processed before peak searching. Using the peak finding algorithm in EVA software, peaks selected with a threshold value of 1 were used for preliminary peak assignment. To ensure accuracy, adjustments were made manually; the results of the automatic assignments were checked visually, and the peak positions were adjusted to the maximum of the peaks. Typically, peaks with relative intensity ≥3% were selected. Peaks that were not resolved or consistent with noise were generally not selected. Typical error associated with peak position from PXRD as specified in USP is up to +/-0.2° 2-theta (USP-941).

One representative diffraction pattern was observed for the P23 crystalline form and is shown in FIG. 3. A list of diffraction peaks in 20 degrees and relative intensities with a relative intensity of ≥3.0% PXRD from the crystalline P23 sample is shown in Table X-P23 below.

In some embodiments, the present invention provides a compound that is tert-butyl-(2S)-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ]-1'-carboxylate or its salt. In some embodiments, the present invention provides a compound that is tert-butyl-(2S)-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ]-1'-carboxylate. In certain other embodiments, the present invention provides a crystalline form of tert-butyl-(2S)-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]- 1'-carboxylate. In certain other embodiments, the crystalline form of tert-butyl-(2S)-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'- carboxylate exhibits a powder X-ray diffraction pattern including at least one characteristic peak expressed in 20 degrees, as shown in Table X-P23.

In some embodiments, a crystalline form of tert-butyl-(2S)-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate shows a powder x-ray diffraction pattern including at least two characteristic peaks expressed in 20 degrees, which are presented in Table X-P23. In some embodiments, a crystalline form of tert-butyl-(2S)-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate shows a powder x-ray diffraction pattern including at least three characteristic peaks expressed in 20 degrees, which are presented in Table X-P23. In some embodiments, a crystalline form of tert-butyl-(2S)-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate shows a powder x-ray diffraction pattern including at least four (for example, 4, 5, 6, 7, 8, 9 or 10) characteristic peaks, expressed in degrees 20, which are presented in Table X-P23. In some embodiments, a crystalline form of tert-butyl-(2S)-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate shows a powder X-ray diffraction pattern substantially as shown in FIG. 3.

Receiving P25

Di-tert-butyl-7-methyl-6-(2-methyl-2E-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]- 1,1'-dicarboxylate (P25)

Step 1. Synthesis of di-tert-butyl-6-ethenyl-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1,1'-dicarboxylate (C63 ).

Mixture P21 (15.0 g, 31.1 mmol), potassium vinyl trifluoroborate (10.4 g, 77.6 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (2.27 g, 3.10 mmol) and potassium phosphate (19.8 g, 93.3 mmol) in N,N-dimethylformamide (500 ml) was stirred at 95°C for 16 hours, then the reaction mixture was filtered; the filtrate was poured into water (4 L) and extracted with ethyl acetate (2×800 ml). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. The residue was combined with the product of a similar reaction carried out using P21 (5.00 g, 10.4 mmol) and the mixture was purified by chromatography on silica gel (gradient: 0% to 20% ethyl acetate in petroleum ether) to give C63 as a white solid . Combined yield: 17.1 g, 38.9 mmol, 94%. LCMS m/z 430.3 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.46 (br.s, 1H), 6.83 (dd, J=11.4, 11.1 Hz, 1H), 5.59 (b.d , J=11.4 Hz, 1H), 5.37-5.24 (m, 1H), [3.90 (d, J=11.0 Hz) and 3.72 (d, J=11.0 Hz), total 1H], 3.64-3.41 (m, 2H), 3.38-3.24 (m, 1H), [2.86-2.64 (m), 2.62-2 .39 (m) and 2.16-1.72 (m), total 9H], 1.45 (s, 18H).

Step 2. Synthesis of di-tert-butyl-6-formyl-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1,1'-dicarboxylate (C64 ).

A solution of C63 (17.0 g, 39.6 mmol) in dichloromethane (200 ml) was cooled to -78°C and a stream of ozone-enriched oxygen was introduced until a stable blue color was established. After another 5 minutes, the reaction mixture was bubbled with a stream of dry nitrogen until the blue color disappeared, then triphenylphosphine (20.7 g, 78.9 mmol) was added. The resulting mixture was heated to 25°C and stirred for 2 hours, after which LCMS analysis showed the presence of C64: LCMS m/z 454.3 [M+Na ⁺ ]. The reaction mixture was concentrated in vacuo, then the residue was purified by chromatography on silica gel (gradient: 0% to 50% ethyl acetate in petroleum ether) to obtain C64 as a colorless gum. Yield: 9.98 g, 23.1 mmol, 58%.

Step 3. Synthesis of di-tert-butyl-7-methyl-6-[(2-methylhydrazinylidene)methyl]-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1 ,1'-dicarboxylate (C65).

A solution of methylhydrazine sulfate (3.20 g, 22.2 mmol) and triethylamine (7.78 ml, 55.8 mmol) in methanol (50 ml) was stirred at 25°C for 5 minutes, then a solution of C64 (7.98 g, 18.5 mmol) in methanol (20 ml). After stirring the reaction mixture at 25°C for 1 hour, collecting the precipitate by filtration gave C65 as a white solid. Yield: 7.60 g, 16.5 mmol, 89%. LCMS m/z 460.3 [M+H] ⁺ .

Step 4. Synthesis of di-tert-butyl-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3' -pyrrolidine]-1,1'-dicarboxylate (P25).

To a solution of C65 (6.70 g, 14.6 mmol) in a mixture of 2,2,2-trifluoroethanol (35 ml) and dichloromethane (35 ml) was added di-tert-butyl azodicarboxylate (4.36 g, 18.9 mmol) followed by the addition of [bis(trifluoroacetoxy)iodo]benzene (33.2 g, 77.2 mmol). The reaction mixture was stirred at 25°C for 30 minutes, then the mixture was poured into saturated aqueous sodium sulfite (300 ml) and extracted with dichloromethane (2×100 ml). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo; chromatography on silica gel (gradient: 0% to 20% ethanol in dichloromethane) gave P25 as a white solid. Yield: 2.10 g, 4.32 mmol, 30%. LCMS m/z 508.3 [M+Na ⁺ ]. ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.11 (s, 1H), 4.44 (s, 3H), [3.93 (d, J=11.3 Hz) and 3.86 ( d, J=11.1 Hz), total 1H], 3.68-3.56 (m, 1H), 3.56-3.46 (m, 1H), 3.46-3.3 (m, 1H, presumably; partially hidden by solvent peak), 2.92-2.81 (m, 2H), 2.73 (s, 3H), [2.69-2.58 (m) and 2.58-2, 47 (m), total 1H], 2.15-1.88 (m, 3H), 1.48 (br. s, 18H).

Getting P26

(2S)-7-Methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine], dihydrochloride salt (P26)

Step 1. Separation of di-tert-butyl-(2R)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin- 2,3'-pyrrolidine]-1,1'-dicarboxylate (C66) and di-tert-butyl-(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3, 4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1,1'-dicarboxylate (C67).

Separation of P25 (2.37 g, 4.88 mmol) into its constituent diastereomers was accomplished using supercritical fluid chromatography {Column: Chiral Technologies Chiralcel OJ-H, 21.2 x 250 mm, 5 μm; Mobile phase 9:1 carbon dioxide/[methanol containing 0.2% (7 M ammonia in methanol)]; Flow rate: 80 ml/min; Back pressure: 120 bar). The first eluting diastereomer was indicated as C66, and the second eluting diastereomer was indicated as C67.

C66 was isolated as a solid. Yield: 1.01 g, 2.0 8 mmol, 43%. Retention time: 2.68 min [Analytical conditions. Column: Chiral Technologies Chiralcel OJ-H, 4.6x250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: methanol containing 0.2% (7 M ammonia in methanol); Gradient: 5% B over 1.0 minutes, then 5% to 60% B over 8.0 minutes; Flow rate: 3.0 ml/min; Back pressure: 120 bar].

C67 was isolated as an oil. Yield: 1.00 g, 2.06 mmol, 42%. Retention time: 3.33 min (Analytical conditions identical to those used for C66).

For assignment of absolute stereochemistry, see below.

Step 2. Synthesis of (2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ], dihydrochloride salt (P26).

A solution of C67 (150 mg, 0.309 mmol) in a mixture of dichloromethane (1.0 ml) and 1,1,1,3,3,3-hexafluoropropan-2-ol (1.0 ml) was treated with a solution of hydrogen chloride in 1.4 -dioxane (4 M; 0.309 ml, 1.24 mmol). After stirring the reaction mixture at room temperature for 2 hours, LCMS analysis showed conversion to P26: LCMS m/z 286.3 [M+H] ⁺ . Concentrating the reaction mixture in vacuo gave P26 as a solid. Yield: 105 mg, 0.293 mmol, 95%.

The indicated absolute stereochemistry was established as follows. This batch P26 was used to prepare 3 and 4 in the Alternative Synthesis of Examples 3 and 4. The correlation between these batches 3 and 4 with the same compounds prepared from a precursor of known absolute stereochemistry (see Examples 3 and 4) is shown in the Alternative Synthesis of Examples 3 and 4.

Alternative Preparation of P26

(2S)-7-Methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine], dihydrochloride salt (P26)

Step 1. Synthesis of tert-butyl-(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2, 3'-pyrrolidine]-1'-carboxylate (C68).

Mixture of 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi-1,3,2-dioxaborolane (299 mg, 1.18 mmol), P23 (300 mg, 0.785 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (32.0 mg, 39.2 µmol) and oven-dried potassium acetate (308 mg, 3.14 mmol ) in 1,4-dioxane (10 ml) was degassed by bubbling the mixture with nitrogen for 5 minutes. The reaction vessel was then sealed and heated at 100°C in an aluminum block for 2 hours, then the mixture was allowed to cool to room temperature. Add 5-bromo-2-methyl-2H-tetrazole (134 mg, 0.822 mmol), dichlorobis(triphenylphosphine)palladium(II) (27.5 mg, 39.2 μmol) and degassed aqueous sodium carbonate (2.0 M ; 0.981 ml, 1.96 mmol) and the reaction mixture was again degassed by sparging with nitrogen for 5 minutes. The mixture was then stirred at 90°C for 18 hours, cooled to room temperature, diluted with ethyl acetate and filtered through diatomaceous earth. The organic layer of the filtrate was washed with saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo; LCMS analysis showed the presence of C68: LCMS m/z 38 6.3 [M+H] ⁺ . Chromatography on silica gel (gradient: 20% to 50% ethyl acetate in heptane) gave C68 as a light yellow oil. Yield: 280 mg, 0.726 mmol, 92%. This batch of C68 was used in Examples 3 and 4 below.

Step 2. Synthesis of (2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ], dihydrochloride salt (P26).

A mixture of C68 (185 mg, 0.480 mmol) and a solution of hydrogen chloride in 2-propanol (1.25 M; 1.9 ml, 2.4 mmol) was heated to 50°C for 1 hour. Concentration of the reaction mixture in vacuo gave P26 as a solid, which was used without further purification. Yield: 170 mg, 0.47 mmol, 98%.

Receiving P27

[(2S)-1'-(tert-Butoxycarbonyl)-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-6-yl]boronic acid (P27 )

Reaction vessel containing a mixture of P23 (19.5 g, 51.0 mmol), potassium acetate (12.5 g, 127 mmol), sodium tert-butoxide (49.0 mg, 0.510 mmol), chloro(2-dicyclohexylphosphino- 2',4',6'-triisopropyl-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(II) [XPhos Pd G2; 401 mg, 0.510 mmol) and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos; 729 mg, 1.53 mmol) were purged with nitrogen. Methanol (200 ml), ethane-1,2-diol (20 ml) and tetrahydroxydiboron (11.4 g, 127 mmol) were then added, then the reaction mixture was bubbled with nitrogen for 10 minutes. The reaction mixture was heated to an internal temperature of 50°C for 2 hours, cooled to room temperature and then to 0°C and adjusted to pH 14 by adding aqueous sodium hydroxide (4 M; 80 ml) {Caution: gas evolution}. The resulting mixture was stirred at room temperature for 30 minutes and filtered; the filtrate was concentrated in vacuo and extracted twice with tert-butyl methyl ether. The combined organic layers were then extracted with aqueous sodium hydroxide (2 M; 2×100 ml). All aqueous layers were combined and the stirred mixture was treated dropwise with hydrochloric acid (4 M; approximately 20 ml) until solids precipitated (this occurred at a pH of approximately 9). After stirring the mixture at room temperature for another 30 minutes, the mixture was extracted four times with ethyl acetate. The combined ethyl acetate layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo to give P27 as a light yellow powder. Yield: 12.5 g, 36.0 mmol, 71%. LCMS m/z 348.4 [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ), characteristic peaks: δ 7.74 (b s, 1H), 3.46-3.35 (m, 2H), 2.92-2.72 (m , 2H), 2.48 (s, 3H), 2.12-1.83 (m, 4H), [1.47 (s) and 1.46 (s), total 9H].

Getting P28

(2S)-7-Methyl-6-(pyrimidine-2-ml)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine], dihydrochloride salt (P28)

Step 1. Synthesis of tert-butyl-(2S)-7'-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] -1'-carboxylate (C69).

A mixture of oven-dried potassium acetate (2.07 g, 21.1 mmol), P23 (substance from Preparations P23 and P24; 2.02 g, 5.28 mmol), 5,5,5',5' was bubbled with nitrogen. -tetramethyl-2,2'-bi-1,3,2-dioxaborinane (1.79 g, 7.92 mmol) and [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (216 mg, 0.264 mmol) in 1,4-dioxane (20 ml) for 5 minutes. The reaction mixture was then heated in a 105°C aluminum block for 2 hours, the mixture was then allowed to cool to room temperature and then treated with 2-bromopyrimidine (840 mg, 5.28 mmol), additional [1,1'-bis(diphenylphosphino) complex )ferrocene]dichloropalladium(II) with dichloromethane (216 mg, 0.264 mmol) and aqueous sodium carbonate (2.0 M; 7.93 ml, 15.9 mmol). The reaction mixture was purged with nitrogen, then the mixture was heated to 100°C for 18 hours, after which LCMS analysis showed conversion to C69: LCMS m/z 382.4 [M+H] ⁺ . The reaction mixture was cooled, partitioned between aqueous ammonium chloride and ethyl acetate, and then the entire mixture was filtered through a pad of diatomaceous earth. The filter cake was washed with water and ethyl acetate, and the aqueous layer of the combined filtrate was extracted with ethyl acetate (2×30 ml). All organic layers were combined and washed successively with water (100 ml) and saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo. The residue (2.9 g) was dissolved in ethyl acetate (10 ml) and treated with SiliaMetS Thiol (SiliCycle, R51030B; 2 g); the resulting mixture was heated at reflux for 10 minutes and then cooled to room temperature. Filtration through a pad of diatomaceous earth provided a filtrate, which was concentrated under reduced pressure to give C69 as a brown gum (2 g). This substance was used in the next step without further purification.

Step 2. Synthesis of (2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine], dihydrochloride salt (P28 ).

A hydrogen chloride solution was prepared by slowly adding acetyl chloride (1.50 mL, 21.1 mmol) to 2-propanol (4 mL). In a separate flask, C69 (from the previous step; 2 g; ≤5.28 mmol) was dissolved in a mixture of propan-2-yl acetate (15 ml) and 2-propanol (15 ml); this required heating at 50°C. Once the solution was obtained, hydrogen chloride solution was slowly added to it and the reaction mixture was heated at 50°C for 2 hours. The mixture was then allowed to cool slowly to room temperature while stirring; stirring was continued at room temperature for 18 hours. The resulting solid was collected by vacuum filtration under nitrogen to provide P28 as a hygroscopic solid. Yield: 750 mg, 2.12 mmol, 40% in 2 stages. LCMS m/z 282.3 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.91 (d, J=4.9 Hz, 2H), 8.58 (s, 1H), 7.43 (t, J=4.9 Hz , 1H), 3.76-3.66 (m, 1H), 3.66-3.52 (m, 2H), 3.46 (d, AB quartet component, J=12.5 Hz, 1H), 3.12-2.95 (m, 2H), 2.90 (s, 3H), 2.49-2.38 (m, 1H), 2.37-2.25 (m, 1H), 2. 24-2.06 (m, 2H).

The indicated absolute stereochemistry was assigned based on the conversion of this batch of P28 to Example 14; The absolute stereochemistry of 14 was determined by single crystal X-ray diffraction (see Example 14 below).

Getting P29

tert-Butyl-4,7-dimethyl-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P29)

Step 1. Synthesis of tert-butyl-3-amino-3-(prop-2-en-1-yl)pyrrolidin-1-carboxylate (C70).

A mixture of tert-butyl 3-oxopyrrolidine-1-carboxylate (500 mg, 2.70 mmol) and ammonia in methanol (7 M; 3.9 mL, 27 mmol) was stirred at room temperature for 30 minutes. To this was then added dropwise a solution of 4,4,5,5-tetramethyl-2-(prop-2-en-1-yl)-1,3,2-dioxaborolane (907 mg, 5.40 mmol) in methanol and the reaction mixture was stirred at room temperature for 18 hours. Volatiles were removed in vacuo and the residue was chromatographed on silica gel (gradient: 0% to 10% methanol in dichloromethane) to give C70. Yield: 200 mg, 0.884 mmol, 33%. ^1H NMR (400 MHz, chloroform-d) δ 5.91-5.76 (m, 1H), 5.20 (m, 1H), 5.15 (br d, J=11 Hz, 1H), 3.53-3.38 (m, 2H), 3.32-3.08 (m, 2H), 2.28 (d, J=7.5 Hz, 2H), 1.89-1.79 ( m, 1H), 1.73-1.63 (m, 1H), 1.46 (s, 9H).

Step 2. Synthesis of tert-butyl-3-[(3-chloro-6-methylpyridin-2-yl)amino]-3-(prop-2-en-1-yl)pyrrolidin-1-carboxylate (C71).

Vessel containing a mixture of 2,3-dichloro-6-methylpyridine (100 mg, 0.617 mmol), C70 (168 mg, 0.742 mmol), palladium(II) acetate (6.93 mg, 30.9 µmol), 2-dicyclohexylphosphino -2',6'-diisopropoxybiphenyl (RuPhos; 28.8 mg, 61.7 µmol) and sodium tert-butoxide (119 mg, 1.24 mmol) in 1,4-dioxane (8 ml) were purged with nitrogen, sealed and heated at 80°C overnight. LCMS analysis showed conversion to C71: LCMS m/z 352.3 (observed chlorine isotopic pattern) [M+H] ⁺ , then the reaction mixture was cooled to room temperature and partitioned between water and dichloromethane. The aqueous layer was extracted with dichloromethane and the combined organic layers were washed with saturated aqueous sodium chloride, dried over magnesium sulfate, filtered, concentrated in vacuo and chromatographed on silica gel (gradient: 0% to 50% ethyl acetate in heptane) to obtain C71 as an oil, which hardened upon standing. Yield: 121 mg, 0.344 mmol, 56%. ^1H NMR (400 MHz, chloroform-d) δ 7.29 (d, J=8.1 Hz, 1H), 6.42-6.34 (m, 1H), 5.82-5.68 (m , 1H), 5.11-5.03 (m, 1H), 5.03-4.93 (m, 1H), 3.79-3.69 (m, 1H), [3.62 (d, component of the AB quartet, J=11.6 Hz), 3.56 (d, component of the AB quartet, J=11.4 Hz) and 3.54-3.36 (m), total 3H], 2.95-2 .83 (m, 1H), 2.76-2.63 (m, 1H), 2.45-2.28 (m, 1H), 2.34 (s, 3H), 2.08-1.96 (m, 1H), 1.50-1.41 (broad s, 9H).

Step 3. Synthesis of tert-butyl-4,7'-dimethyl-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P29).

A mixture of C71 (40 mg, 0.11 mmol), tris(dibenzylideneacetone)dipalladium(0) (5.20 mg, 5.68 μmol), N-cyclohexyl-N-methylcyclohexanamine (111 mg, 0.568 mmol) and three -tert-butylphosphine (1.15 mg, 5.68 μmol) in N,N-dimethylformamide (1.0 ml) was degassed and then heated at 80°C for 2 hours. The temperature was raised to 120°C and the reaction mixture was maintained at this temperature for 3 days. LCMS analysis showed conversion to P29: LCMS m/z 316.3 [M+H] ⁺ . The reaction mixture was cooled to room temperature, then the mixture was partitioned between ethyl acetate and water, and the aqueous layer was extracted twice with ethyl acetate. The combined organic layers were washed with saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo; chromatography on silica gel (gradient: 0% to 100% ethyl acetate in heptane) gave P29. Yield: 30 mg, 95 µmol, 86%. ¹ H NMR (400 MHz, chloroform-d), characteristic peaks: δ 7.13 (d, J=7.5 Hz, 1H), 6.40 (d, J=7.5 Hz, 1H), 5, 27 (broad s, 1H), 5.06-4.99 (broad s, 1H), 3.58-3.40 (m, 3H), 3.31-3.21 (m, 1H), 2.31 (s, 3H), [1.96 (s) and 1.96 (s), total 3H], [1.46 (s) and 1.44 (s), total 9H].

Getting P30

tert-Butyl-1-benzyl-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P30)

Step 1. Synthesis of 1,1'-dibenzyl-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] (C72).

The conversion of C43 to C72 was carried out using the method described for the synthesis of C47 from C43 in Preparations P17 and P18, using 1-phenylmethanamine instead of 1-(4-methoxyphenyl)methanamine. Chromatography on silica gel (gradient: 0% to 10% methanol in dichloromethane) gave C72. Yield for the cyclization step to give C72: 580 mg, 1.51 mmol, 69%.

Step 2. Synthesis of tert-butyl-1-benzyl-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (P30).

A mixture of C72 (550 mg, 1.43 mmol), palladium on carbon (50 mg, 0.143 mmol) and di-tert-butyl dicarbonate (376 mg, 1.72 mmol) in methanol (20 ml) was hydrogenated overnight at 75 p.m. /in ² (5.273 kg/cm ² ). The reaction mixture was filtered through diatomaceous earth and the filtrate was concentrated in vacuo; chromatography on silica gel (gradient: 0% to 100% ethyl acetate in heptane) gave P30 as a white semi-solid. Yield: 482 mg, 1.22 mmol, 85%. ^1H NMR (400 MHz, chloroform-d) δ 7.29-7.07 (m, 6H, presumably; partially hidden by solvent peak), 6.39 (d, J=7.2 Hz, 1H), 5, 15-4.99 (m, 1H), 4.97-4.78 (m, 1H), 3.58-3.19 (m, 4H), 2.87-2.71 (m, 2H), 2.31-2.16 (m, 1H), 2.24 (s, 3H), 2.07-1.95 (m, 1H), 1.92-1.79 (m, 1H), 1. 75-1.63 (m, 1H), [1.45 (s) and 1.43 (s), total 9H].

Receiving P31

6-[5-(Difluoromethyl)-1-methyl-1H-1,2,4-triazol-3-yl]-1-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridin-2, 3'-pyrrolidine] (P31)

Step 1. Synthesis of 1,1'-dibenzyl-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] (C73).

1,3-Dibromo-5,5-dimethylimidazolidine-2,4-dione (532 mg, 1.86 mmol) was added in portions to a 0°C solution of C72 (1.19 g, 3.10 mmol) in dichloromethane (16 ml). LCMS analysis after 1 hour showed conversion to C73: LCMS m/z 462.2 (observed bromine isotope pattern) [M+H] ⁺ . The reaction mixture was diluted with dichloromethane (20 ml), washed successively with saturated aqueous sodium sulfite, saturated aqueous sodium bicarbonate and saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 50% ethyl acetate in heptane) gave C73 as an oil. Yield: 980 mg, 2.12 mmol, 68%. ¹ H NMR (400 MHz, chloroform-d) δ 7.32-7.12 (m, 11H, presumably; partially hidden by solvent peak), 5.03 (AB quartet, J _AB = 16.3 Hz, Δν _AB = 2b,b Hz, 2H), 3.54 (AB quartet, J _AB =13.1 Hz, Δν _AB =41.8 Hz, 2H), 2.93 (d, J=10.2 Hz, 1H), 2.88 (ddd, J=8.5, 8.5, 3.4 Hz, 1H), 2.84-2.75 (m, 1H), 2.74-2.65 (m, 1H), 2.40-2.32 (m, 1H), 2.29 (s, 3H), 2.19 (d, d=10.2 Hz, 1H), 2.12 (ddd, d=13.4, 8.3, 8.3 Hz, 1H), 1.99 (ddd, d=13.7, 8.8, 5.2 Hz, 1H), 1.93-1.85 (m, 1H), 1 .81 (ddd, d=13.4, 7.3, 3.5 Hz, 1H).

Step 2. Synthesis of 1,1'-dibenzyl-7-methyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)3,4-dihydro-1H-spiro [ 1,8-naphthyridine-2,3'-pyrrolidine] (C74).

4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi-1,3,2-dioxaborolane (148 mg, 0.583 mmol), C73 ( 180 mg, 0.38 9 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (31.8 mg, 38.9 µmol) and oven-dried potassium acetate (153 mg, 1.56 mmol) in 1,4-dioxane (5 ml). The reaction mixture was bubbled with nitrogen for 5 minutes, then the vessel was sealed and heated at 100°C in an aluminum block for 2 hours. LCMS analysis showed the presence of C74: LCMS m/z 510.4 [M+H] ⁺ . The reaction mixture was cooled to room temperature, then the mixture was diluted with ethyl acetate and filtered through a pad of diatomaceous earth. The filtrate was concentrated in vacuo to give compound C74, which was used directly in the next step.

Step 3. Synthesis of 1,1'-dibenzyl-6-[5-(difluoromethyl)-1-methyl-1H-1,2,4-triazol-3-yl]-7-methyl-3,4-dihydro-1H -spiro[1,8-naphthyridine-2,3'-pyrrolidine] (C75).

Dichlorobis(triphenylphosphine)palladium(II) (5.24 mg, 7.46 µmol), aqueous potassium phosphate (2.0 M; 0.466 ml, 0.932 mmol) and 3-bromo-5-(difluoromethyl)-1-methyl -1H-1,2,4-triazole (P33; 79.1 mg, 0.373 mmol) was added to a solution of C74 (from the previous step; ≤0.389 mmol) in tetrahydrofuran (5 ml). The reaction mixture was purged with nitrogen, then the reaction vessel was sealed and heated at 70°C in an aluminum block for 1 hour. The temperature was then raised to 100°C and heating was continued overnight. 3-Bromo-5-(difluoromethyl)-1-methyl-1H-1,2,4-triazole (P33; 79.1 mg, 0.373 mmol) was added again and heating was continued for another 6 hours, then the reaction mixture was cooled and partitioned between ethyl acetate and water. The aqueous layer was extracted twice with ethyl acetate and the combined organic layers were washed with saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 100% ethyl acetate in heptane) gave C75. Yield: 105 mg, 0.204 mmol, 52% in 2 stages. LCMS m/z 515.3 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.69 (s, 1H), 7.33-7.19 (m, 9H, presumably; partially hidden by solvent peak), 7.18-7.12 (m , 1H), 6.85 (t, J _HF =52.6 Hz, 1H), 5.14 (AB quartet, J _AB =16.3 Hz, Δν _AB =17.6 Hz, 2H), 4.05 (s, 3H), 3.54 (AB quartet, J _AB =13.0 Hz, Δν _AB =38.8 Hz, 2H), 2.97 (d, J=10.2 Hz, 1H), 2, 93-2.81 (m, 2H), 2.81-2.72 (m, 1H), 2.53 (s, 3H), 2.41-2.32 (m, 1H), 2.22 ( d, J=10.2 Hz, 1H), 2.15 (ddd, J=13.5, 8.3, 8.2 Hz, 1H), 2.06-1.97 (m, 1H), 1 .96-1.88 (m, 1H), 1.84 (ddd, J=13.4, 7.3, 3.4 Hz, 1H).

Step 4. Synthesis of 6-[5-(difluoromethyl)-1-methyl-1H-1,2,4-triazol-3-yl]-7'-methyl-3,4-dihydro-1H-spiro[1,8 -naphthyridine-2,3'-pyrrolidine] (P31).

Palladium on carbon (10%, wet, containing water; 20 mg) was added to a solution of C75 (105 mg, 0.204 mmol) in methanol (5 ml) containing a drop of formic acid, and the resulting mixture was hydrogenated overnight at room temperature and 70 lb/in ² (4.922 kg/cm ² ). After filtration, the filtrate was concentrated in vacuo to give P31 as a light yellow solid. Yield: 63 mg, 0.19 mmol, 93%. LCMS m/z 335.2 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.20 (s, 1H), 6.86 (t, J _HF =52.4 Hz, 1H), 4.10 (s, 3H), 3.78 -3.51 (m, 3H), 3.41 (d, J=12.3 Hz, 1H), 2.99-2.85 (m, 2H), 2.83 (s, 3H), 2, 29-2.19 (m, 2H), 2.19-2.01 (m, 2H).

Getting P32

(2S)-6-[5-(Difluoromethyl)-1-methyl-1H-1,2,4-triazol-3-yl]-7-methyl-3,4-dihydro-1H-spiro[1,8- naphthyridine-2,3'-pyrrolidine], dihydrochloride salt (P32)

Step 1. Synthesis of tert-butyl-(2S)-6-[5-(difluoromethyl)-1-methyl-1H-1,2,4-triazol-3-yl]-7-methyl-3,4-dihydro- 1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (C76).

Using the method described for the synthesis of C68 from P23 in the Alternative Preparation of P26, P23 (220 mg, 0.575 mmol) and 3-bromo-5-(difluoromethyl)-1-methyl-1H-1,2,4-triazole ( P33; 128 mg, 0.604 mmol) was used to obtain C76. Chromatography on silica gel (gradient: 20% to 50% ethyl acetate in heptane) gave C76 as a white solid. Yield: 110 mg, 0.253 mmol, 44%. LCMS m/z 435.4 [M+H] ⁺ .

Step 2. Synthesis of (2S)-6-[5-(difluoromethyl)-1-methyl-1H-1,2,4-triazol-3-yl]-7-methyl-3,4-dihydro-1H-spiro[ 1,8-naphthyridine-2,3'-pyrrolidine], dihydrochloride salt (P32).

A mixture of C76 (110 mg, 0.253 mmol) in a solution of hydrogen chloride in 2-propanol (1.25 M, 1.0 ml, 1.2 mmol) was heated at 50°C for 1 hour. LCMS analysis showed the formation of P32: LCMS m/z 335.3 [M+H]+. Concentration in vacuo gave P32 as a solid. Yield: 74 mg, 0.182 mmol, 72%.

Getting P33

3-Bromo-5-(difluoromethyl)-1-methyl-1H-1,2,4-triazole (P33)

[Bis(2-methoxyethyl)amino]sulfur trifluoride (47.0 ml, 255 mmol) was added dropwise to a 0°C mixture of 3-bromo-1-methyl-1H-1,2,4-triazole-5-carbaldehyde ( 24.2 g, 127 mmol) in dichloromethane (400 ml); the reaction mixture was allowed to warm to 20°C and stirred at 20°C for 16 hours. After adding aqueous sodium bicarbonate solution dropwise, the resulting mixture was extracted with dichloromethane (3×300 ml). The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 50% to 70% dichloromethane in petroleum ether) gave 3-bromo-5-(difluoromethyl)-1-methyl-1H-1,2,4-triazole (P33) as a light yellow oil ( 17.7 g). This material was combined with the product of a similar reaction, which was carried out using 3-bromo-1-methyl-1H-1,2,4-triazole-5-carbaldehyde (12.0 g, 63.2 mmol); concentration under reduced pressure gave P33 as a white solid. Combined yield: 2 5.2 g, 119 mmol, 63%. LCMS m/z 212 (observed bromine isotopic pattern) [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 7.06 (t, J _HF =52.2 Hz, 1H), 4.01 (s, 3H).

Examples 1 and 2

(2R)-2-(5-Chloro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1 (1) and (2R)-2-(5-Chloro-2-methoxypyridin- 4-yl)-1-[7-methyl-6-(2-methyl-2E-tetrazol-5-yl)-3,4-dihydro-1E-spiro[1,8-naphthyridine-2,3'-pyrrolidine ]-1'-yl]propan-1-one, DIAST-2 (2)

Step 1. Synthesis of 7'-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine], dihydrochloride salts (C77).

A solution of hydrogen chloride in 1,4-dioxane (4.0 M; 0.587 ml, 2.35 mmol) was added to a solution of P25 (285 mg, 0.587 mmol) in a mixture of dichloromethane (1 ml) and 1, 1, 1, 3, 3, 3-hexafluoropropan-2-ol (1 ml). After stirring the reaction mixture at room temperature for 2 hours, LCMS analysis showed the presence of C77: LCMS m/z 286.3 [M+H] ⁺ . Removal of volatiles in vacuo gave C77 as a white solid. Yield: 210 mg, 0.586 mmol, quantitative.

Step 2. Synthesis of (2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4 -dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1 (1) and (2R)-2-(5-chloro- 2-methoxypyridin-4-yl)-1-[7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2, 3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-2 (2).

To a solution of P2 (65.7 mg, 0.305 mmol) in acetonitrile (1 ml) was added pyridinium trifluoromethanesulfonate (140 mg, 0.611 mmol) and the mixture was stirred until a solution was formed. 1,1'-carbonyldiimidazole (49.4 mg, 0.305 mmol) was added in one portion and the reaction mixture was stirred at room temperature for 45 minutes, then a solution of C77 (104 mg, 0.290 mmol) in acetonitrile (2 ml) was added. After stirring the reaction mixture at room temperature for 3 hours, the mixture was diluted with an aqueous solution of ammonium chloride, and the resulting mixture was extracted three times with ethyl acetate. The combined organic layers were dried over magnesium sulfate, filtered and concentrated in vacuo. Silica gel chromatography (gradient: 20% to 100% ethyl acetate in heptane) gave mixture 1 and 2 as a white solid (105 mg), LCMS m/z 483.3 (chlorine isotope pattern observed) [M+H] ⁺ . Separation of diastereomers was carried out by supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IB, 21×250 mm, 5 μm; Mobile phase 85:15 carbon dioxide/(0.2% ammonium hydroxide in methanol); Flow rate: 75 ml/min; Back pressure: 200 bar]; the first eluting diastereomer was reported as 1 {(2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(2-methyl-2H-tetrazol-5-yl) -3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1}, and the second eluting diastereomer as 2 {(2R )-2-(5-chloro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-2}.

1 - Yield: 7.2 mg, 15 µmol, 5%. LCMS m/z 483.2 [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ) δ [8.15 (s) and 8.14 (s), total 1H], [7.87 (s) and 7.83 (s), total 1H] , [6.81 (s) and 6.75 (s), total 1H], [4.39 (s) and 4.39 (s), total 3H], [4.31 (sq., J=6 ,8 Hz) and 4.22 (sq., J=6.9 Hz), total 1H], 3.90 (s, 3H), [3.9-3.81 (m) and 3.76-3 .52 (m), total 3H], [3.48 (d, component of AB quartet, J=12.3 Hz) and 3.35 (d, J=10.7 Hz), total 1H], [2, 93-2.72 (m) and 2.6-2.46 (m), total 2H], [2.60 (s) and 2.58 (s), total 3H], 2.16-1.84 (m, 3H), 1.80-1.72 (m, 1H), [1.43 (d, J=6.8 Hz) and 1.42 (d, J=6.9 Hz), total 3H ]. Retention time: 2.32 minutes [Analytical conditions. Column: Chiral Technologies Chiralpak IB, 4.6x100 mm, 5 µm; Mobile phase 3:2 carbon dioxide/(0.2% ammonium hydroxide in methanol); Flow rate: 1.5 ml/min; Back pressure: 120 bar].

2 - Yield: 7.9 mg, 16 µmol, 6%. LCMS m/z 483.2 [M+H] ⁺ . Retention time: 2.53 minutes (Analytical conditions identical to those used for 1).

Examples 3 and 4

2-(6-Methoxy-2-methylpyrimidin-4-yl)-1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-2H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1 (3) and 2-(6-Methoxy-2-methylpyrimidin-4-yl) -1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ]-1'-yl]propan-1-one, DIAST-2 (4)

Trifluoroacetic acid (2 ml) was added to a solution of C68 (280 mg, 0.72 6 mmol) in dichloromethane (10 ml) and the reaction mixture was stirred at room temperature for 2 hours. The mixture was then concentrated in vacuo and evaporated twice with ethyl acetate to give the deprotected substance as a dark brown oil (200 mg), LCMS m/z 286.3 [M+H] ⁺ . A portion of this oil (35 mg) and P4 (24.9 mg, 0.123 mmol) were dissolved in dichloromethane (3 ml) and treated with O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU; 70.0 mg, 0.184 mmol) and triethylamine (51.3 μl, 0.368 mmol), followed by N,N-dimethylformamide (2 drops) to aid solubility. After stirring the reaction mixture at room temperature overnight, the mixture was diluted with dichloromethane, washed successively with aqueous sodium bicarbonate and saturated aqueous sodium chloride, filtered, dried and concentrated under reduced pressure. Separation of the constituent diastereomers was carried out using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IA, 21×250 mm, 5 μm; Mobile phase: 7:3 carbon dioxide/(0.5% ammonium hydroxide in methanol); Flow rate: 75 ml/min; Back pressure: 120 bar]; the first eluting diastereomer was reported as 3{2-(6-methoxy-2-methylpyrimidin-4-yl)-1-[{2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl) -3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1}, and the second eluting diastereomer as 4 {2- (6-methoxy-2-methylpyrimidin-4-yl)-1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-2}.

3 - Yield: 3.1 mg, 6.7 µmol, 5%. LCMS m/z 464.3 [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ) δ [7.86 (s) and 7.85 (s), total 1H], [6.65 (s) and 6.61 (s), total 1H] , [4.39 (s) and 4.39 (s), total 3H], [4.05 (sq., J=7.0 Hz), 4.01-3.89 (m), 3.88 -3.55 (m), 3.59 (s) and 3.53 (s), total 5H], [3.98 (s) and 3.96 (s), total 3H], 2.95-2 .75 (m, 2H), [2.60 (s), 2.58 (s) and 2.55 (s), total 6H], 2.19-1.71 (m, 4H), [1, 46 (d, J=7.1 Hz) and 1.44 (d, J=7.1 Hz), total 3H]. Retention time: 2.47 min [Analytical conditions. Column: Chiral Technologies Chiralpak IA, 4.6x100 mm, 5 µm; Mobile phase: 65:35 carbon dioxide/(methanol containing 0.5% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar].

4 - Yield: 3.6 mg, 7.8 µmol, 6%. LCMS m/z 486.3 [M+Na ⁺ ]. Retention time: 2.92 min (Analytical conditions identical to those used for 3).

Alternative Synthesis of Examples 3 and 4

2-(6-Methoxy-2-methylpyrimidin-4-yl)-1-[(2S)-7'-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro- 1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1 (3) and 2-(6-Methoxy-2-methylpyrimidin-4-yl )-1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'- pyrrolidin]-1'-yl]propan-1-one, DIAST-2 (4)

Solution P26 (substance from Preparation P26; 105 mg, 0.293 mmol), P4 (69.0 mg, 0.352 mmol), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (EDCI; 169 mg, 0.882 mmol) , 1H-benzotriazol-1-ol (119 mg, 0.881 mmol) and N,N-diisopropylethylamine (0.255 ml, 1.46 mmol) in N,N-dimethylformamide (3 ml) were stirred at 25°C for 16 hours. The reaction mixture was then diluted with water (40 ml) and extracted with ethyl acetate (3×30 ml) and the combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. After silica gel chromatography (gradient: 0% to 10% methanol in dichloromethane), the two diastereomers were separated using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ, 30×250 mm, 5 μm; Mobile phase: 85:15 carbon dioxide/(2-propanol containing 0.2% propan-2-amine); Flow rate: 80 ml/min; Back pressure: 100 bar]. The first eluting diastereomer was reported as 3{2-(6-methoxy-2-methylpyrimidin-4-yl)-1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl) -3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1}, and the second eluting diastereomer as 4 {2- (6-methoxy-2-methylpyrimidin-4-yl)-1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-2}.

3 - Yield: 30 mg, 65 µmol, 22%. LCMS m/z 464.2 [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ) δ [7.86 (s) and 7.84 (s), total 1H], [6.65 (s) and 6.61 (s), total 1H] , [4.39 (s) and 4.39 (s), total 3H], [4.04 (sq., J=7.0 Hz), 4.00-3.89 (m), 3.88 -3.60 (m), 3.59 (s) and 3.53 (s), total 5H], [3.97 (s) and 3.96 (s), total 3H], [2.94- 2.74 (m) and 2.67-2.59 (m), total 2H], [2.60 (s), 2.58 (s) and 2.55 (s), total 6H], [2.16 -2.06 (m) and 2.06-1.71 (m), total 4H], [1.46 (d, J=7.1 Hz) and 1.44 (d, J=7.1 Hz ), total 3H]. Retention time: 4.92 min (Analytical conditions. Column: Chiral Technologies Chiralcel OJ, 4.6 x 250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: 2-propanol containing 0.2% propane 2-amine; Gradient: 5% B over 1.00 minutes, then 5% to 60% B over 8.00 minutes; Flow rate: 3.0 ml/min; Back pressure: 120 bar).

4 - Yield: 30 mg, 65 µmol, 22%. LCMS m/z 464.2 [M+H] ⁺ . ^1H NMR (400 MHz, methanol- _d4 ) δ 7.85 (s, 1H), [6.62 (s) and 6.59 (s), total 1H], [4.40 (s) and 4 .39 (s), total 3H], [4.04 (sq., J=7.1 Hz), 3.98-3.85 (m), 3.77-3.60 (m), 3. 58 (d, AB quartet component, J=10.6 Hz) and 3.55-3.48 (m), total 5H], [3.96 (s) and 3.91 (s), total 3H], 2.92-2.76 (m, 2H), [2.59 (s), 2.57 (s), 2.56 (s) and 2.37 (s), total 6H], [2.21 -2.09 (m), 2.08-2.01 (m) and 2.01-1.78 (m), total 4H], [1.47 (d, J=6.9 Hz) and 1 .42 (d, J=7.0 Hz), total 3H]. Retention time: 5.05 min (Analytical conditions identical to those used for 3).

The assignment of the two diastereomers to compounds 3 and 4 was based on the similarity of the ¹ H NMR spectra of this first eluting enantiomer (3) with sample 3 from Examples 3 and 4 described above. Further confirmation was obtained by comparing the chromatographic retention time for this batch 3 with the products from Examples 3 and 4 described above:

Retention Time 3 from Alternative Synthesis of Examples 3 and 4: 2.28 min

Retention time 3 from Examples 3 and 4: 2.4 6 min

Retention time 4 from Examples 3 and 4: 2.91 min

These analyzes were performed using the same analytical method: [Column: Chiral Technologies Chiralpak IA, 4.6×100 mm, 5 µm; Mobile phase: 65:35 carbon dioxide/(methanol containing 0.5% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar].

The biological activity (K _i ) of the corresponding examples from these two experiments also corresponded to the indicated assignments (data from individual batches, which are presented in Table 2):

Example 3 from Examples 3 and 4: 0.36 nM

Example 3 from Alternate Synthesis of Examples 3 and 4: 1.2 nM

Example 4 from Examples 3 and 4: 25 nM

Example 4 from Alternate Synthesis of Examples 3 and 4: 34 nM

Examples 5 and 6

2-[6-(Difluoromethoxy)pyridin-3-yl]-1-[(2S)-1-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8- naphthyridine-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1 (5) and 2-[6-(Difluoromethoxy)pyridin-3-yl]-1-[(2S)- 7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST -2 (6)

A mixture of P28 (50 mg, 0.14 mmol), P5 (30.6 mg, 0.141 mmol), N,N-diisopropylethylamine (0.12 ml, 0.69 mmol) and 2,4,6-tripropyl-1, 3,5,2,4,6-trioxatriphosphinane 2,4,6-trioxide (50% solution in ethyl acetate; 0.25 ml, 0.42 mmol) in dichloromethane (10 ml) was stirred at 25°C for 16 hours , the mixture was then diluted with water (20 ml) and extracted with dichloromethane (2×20 ml). The combined organic layers were washed successively with aqueous sodium bicarbonate (30 ml) and saturated aqueous sodium chloride (30 ml), dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 10% methanol in dichloromethane) gave a mixture of 5 and 6; these diastereomers were separated using reverse phase HPLC (Column: Chiral Technologies Chiralpak IE; 50 x 250 mm; 10 μm; Mobile phase: 95:5 ethanol/acetonitrile; Flow rate: 60 ml/min). The first eluting diastereomer was reported as 5 {2-[6-(difluoromethoxy)pyridin-3-yl]-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro- 1H-Spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1}, and the second eluting diastereomer was reported as 6{2-[6-(difluoromethoxy )pyridin-3-yl]-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'- pyrrolidin]-1'-yl]propan-1-one, DIAST-2}; both were isolated as a white solid.

5 - Yield: 10 mg, 21 µmol, 15%. LCMS m/z 481.3 [M+H] ⁺ . 1H NMR (400 MHz, methanol-d ₄ ) δ [8.82 (d, J=4.9 Hz) and 8.81 (d, J=4.9 Hz), total 2H], [8.19 ( d, J=2.5 Hz) and 8.12 (d, J=2.5 Hz), total 1H], 7.88-7.76 (m, 2H), [7.52 (t, J _HF =73.2 Hz) and 7.43 (t, J _HF =13.1 Hz), total 1H], [7.31 (t, J=4.9 Hz) and 7.31 (t, J=4 ,9 Hz), total 1H], [6.96 (d, J=8.5 Hz) and 6.89 (d, J=8.5 Hz), total 1H], [4.07 (sq., J=6.9 Hz), 4.03-3.91 (m), 3.74-3.63 (m), 3.60 (d, AB quartet component, J=12.1 Hz), 3, 58-3.51 (m), 3.44 (d, J=12.4 Hz) and 3.40 (d, J=10.6 Hz), total 5H], 2.92-2.77 (m , 2H), [2.58 (s) and 2.54 (s), total 3H], [2.22-2.10 (m), 2.08-1.93 (m) and 1.93- 1.77 (m), 4H total], [1.46 (d, J=6.9 Hz) and 1.42 (d, J=6.9 Hz), 3H total]. Retention time: 7.12 min (Analytical conditions. Column: Chiral Technologies Chiralpak AY-H; 4.6 x 250 mm; Mobile phase: 95:5:0.1 ethanol/acetonitrile/diethylamine; Flow rate: 0.6 ml /min).

6 - Yield: 9.8 mg, 2 0 µmol, 14%. LCMS m/z 481.3 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ [8.81 (d, J=4.9 Hz) and 8.80 (d, J=4.9 Hz), total 2H], [8.21 (d, J=2.5 Hz) and 8.16 (d, J=2.5 Hz), total 1H], 7.90-7.78 (m, 2H), [7.54 (t, J _HF =73.2 Hz) and 7.53 (t, J _HF =73.2 Hz), total 1H], [7.31 (t, J=4.9 Hz) and 7.30 (t, J= 4.9 Hz), total 1H], [6.98 (d, J=8.5 Hz) and 6.96 (d, J=8.5 Hz), total 1H], [4.08 (sq. , J=6.9 Hz) and 4.00 (sq., J=6.9 Hz), total 1H], [3.95-3.87 (m), 3.78-3.54 (m) , 3.51 (AB quartet, J _AB =12.3 Hz, Δν _AB =33.2 Hz) and 3.39 (d, J=10.7 Hz), total 4H], [2.94-2, 71 (m) and 2.62-2.49 (m), total 2H], [2.57 (s) and 2.54 (s), total 3H], [2.16-2.04 (m) and 2.02-1.84 (m), total 3H], 1.78-1.70 (m, 1H), [1.45 (d, J=7.0 Hz) and 1.42 (d, J=7.0 Hz), total 3H]. Retention time: 10.66 min (Analytical conditions identical to those used for 5).

Examples 7 and 8

1-[(2S)-7'-Methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl ]-2-[4-(trifluoromethyl)phenyl]propan-1-one, DIAST-1 (7) and 1-[(2S)-7-Methyl-6-(pyrimidin-2-yl)-3,4- Dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]-2-[4-(trifluoromethyl)phenyl]propan-1-one, DIAST-2 (8)

1,1'-Carbonyldiimidazole (240 mg, 1.48 mmol) was added portionwise to a solution of 2-[4-(trifluoromethyl)phenyl]propanoic acid (323 mg, 1.48 mmol) in acetonitrile (5 mL). After stirring the reaction mixture at room temperature for 45 minutes, a mixture of P28 (500 mg, 1.41 mmol) and N,N-diisopropylethylamine (0.504 ml, 2.89 mmol) in acetonitrile (2 ml) was added. Stirring was continued at room temperature for 18 hours, then the reaction mixture was extracted with ethyl acetate. The combined organic layers were washed successively with saturated aqueous sodium bicarbonate and saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was separated into its constituent diastereomers by supercritical fluid chromatography {Column: Chiral Technologies Chiralcel OJ, 30×250 mm, 5 μm; Mobile phase 85:15 carbon dioxide/[methanol containing 0.2% (7 M ammonia in methanol)]; Flow rate: 80 ml/min; Back pressure: 100 bar). The first eluting diastereomer was reported as 7 {1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'- pyrrolidin]-1'-yl]-2-[4-(trifluoromethyl)phenyl]propan-1-one, DIAST-1}, and the second eluting diastereomer was reported as 8 (1-[(2S)-7-methyl- 6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]-2-[4-(trifluoromethyl)phenyl] propan-1-one, DIAST-2}; both were isolated as solids.

7 - Yield: 250 mg, 0.519 mmol, 3%. LCMS m/z 482.4 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ [8.80 (d, J=4.9 Hz) and 8.79 (d, J=4.9 Hz), total 2H], [7.83 (s) and 7.75 (s), total 1H], 7.68-7.62 (m, 2H), [7.54 (d, AB quartet component, J=8, 1 Hz) and 7.49 (d, AB quartet component, J=8.1 Hz), total 2H], [7.28 (t, J=4.9 Hz) and 7.28 (t, J=4.9 Hz), total 1H ], [4.10 (sq., J=6.9 Hz) and 4.00 (sq., J=6.9 Hz), total 1H], [3.92-3.83 (m) and 3 .71 (ddd, J=12.5, 8.5, 6.2 Hz), total 1H], [3.62-3.46 (m), 3.46 (d, AB quartet component, J=12 ,3 Hz) and 3.26 (d, J=10.7 Hz), total 3H], [2.91-2.75 (m), 2.68-2.58 (m) and 2.35- 2.25 (m), total 2H], [2.56 (s) and 2.53 (s), total 3H], [2.13-1.99 (m) and 1.99-1.81 ( m), total 3H], 1.66-1.58 (m, 1H), [1.45 (d, J=6.9 Hz) and 1.42 (d, J=6.9 Hz), total 3H]. Retention time: 4.28 min [Column: Chiral Technologies Chiralcel OJ, 4.6 x 250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: methanol containing 0.2% (7 M ammonia in methanol); Gradient: 5% B over 1.0 minutes, then 5% to 60% B over 8.0 minutes; Flow rate: 3.0 ml/min; Back pressure: 120 bar].

8 - Yield: 260 mg, 0.540 mmol, 38%. LCMS m/z 482.4 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ [8.80 (d, J=4.9 Hz) and 8.79 (d, J=4.9 Hz), total 2H], [7.82 (s) and 7.81 (s), total 1H], [7.64 (d, AB quartet component, J=8.1 Hz) and 7.57 (d, AB quartet component, J=8.2 Hz ), total 2H], [7.52 (d, component of the AB quartet, J=8, 1 Hz) and 7.47 (d, component of the AB quartet, J=8.2 Hz), total 2H], [7, 29 (t, J=4.9 Hz) and 7.28 (t, J=4.9 Hz), total 1H], [4.09 (sq., J=6.9 Hz) and 4.03 ( sq., J=6.9 Hz), total 1H], [3.96-3.87 (m) and 3.46-3.37 (m), total 1H], [3.73-3.63 (m), 3.52 (AB quartet, J _AB =12.3 Hz, Δν _AB =62.6 Hz) and 3.27 (d, J=10.6 Hz), total 3H]. 2.90-2.71 (m, 2H), [2.57 (s) and 2.53 (s), total 3H], [2.15-2.05 (m), 2.04-1, 90 (m) and 1.89-1.70 (m), total 4H], [1.45 (d, J=6.9 Hz) and 1.43 (d, J=6.9 Hz), total 3H]. Retention time: 4.74 min (Analytical conditions identical to those used for 7).

Examples 9, 10, 11 and 12

1-(4,7-Dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethane-1- he, DIAST-1 (9), 1-(4,7-Dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl)-2- (4-fluorophenyl)ethan-1-one, DIAST-2 (10), 1-(4,7-Dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidine] -1'-yl)-2-(4-fluorophenyl)ethan-1-one, DIAST-3 (11) and 1-(4,7-Dimethyl-3,4-dihydro-1H-spiro[1,8- naphthyridin-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethan-1-one, DIAST-4 (12)

Step 1. Synthesis of 1-(4,7-dimethyl-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethan-1-one ( C78).

Trifluoroacetic acid (0.5 ml) was added to a solution of P29 (30 mg, 95 μmol) in dichloromethane (3 ml) and the reaction mixture was stirred at room temperature for 1 hour. After removal of volatiles by concentration in vacuo, the residue was co-evaporated twice with ethyl acetate and heptane, then dissolved in dichloromethane (5 ml). To this solution was added triethylamine (13.3 μl, 95.4 μmol), (4-fluorophenyl)acetic acid (14.7 mg, 95.4 μmol) and O-(7-azabenzotriazol-1-yl)-N, N,N',N'-tetramethyluronium hexafluorophosphate (HATU; 36.2 mg, 95.2 µmol). After stirring the reaction mixture at room temperature for 1 hour, the mixture was concentrated in vacuo and purified by chromatography on silica gel (gradient: 0% to 10% methanol in dichloromethane) to obtain C78 as an off-white powder. Yield: 34 mg, quantitative. LCMS m/z 352.2 [M+H] ⁺ .

Step 2. Synthesis of 1-(4,1'-dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl) )ethan-1-one, DIAST-1 (9), 1-(4,1-dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'- yl)-2-(4-fluorophenyl)ethan-1-one, DIAST-2 (10), 1-(4,7-dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2, 3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethan-1-one, DIAST-3 (11) and 1-(4,7-dimethyl-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethan-1-one, DIAST-4 (12).

A solution of C78 (22 mg, 63 µmol) in methanol (3 ml) was treated with palladium on carbon (10%; 5 mg) and hydrogenated overnight at 50 ^psi (3.515 kg/cm ² ). The reaction mixture was then filtered, concentrated in vacuo and subjected to supercritical fluid chromatography (Column: Chiral Technologies Chiralcel OJ-H, 5 μm; Mobile phase A: carbon dioxide; Mobile phase B: methanol containing 0.2% ammonium hydroxide; Gradient: 3 % to 5% B; Flow rate: 75 ml/min; Back pressure: 200 bar) to separate four diastereomers. The first eluting diastereomer was reported as 9 {1-(4,7-dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl)-2-( 4-fluorophenyl)ethan-1-one, DIAST-1}, eluting second as 10 {1-(4,7-dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethan-1-one, DIAST-2}, eluting third as 11 {1-(4,7-dimethyl-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethan-1-one, DIAST-3} and eluting fourth - as 12 {1-( 4,7-dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethan-1-one, DIAST -4}.

9 - Yield: 1.2 mg, 3.4 µmol, 5%. LCMS m/z 354.3 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.31-7.21 (m, 2H, probable; partially hidden by solvent peak), 7.21-7.16 (m, 1H), 7.05-6 .94 (m, 2H), [6.48 (d, J=7.5 Hz) and 6.47 (d, J=7.5 Hz), total 1H], [3.77-3.52 ( m) and 3.44 (d, component of AB quartet, J=12.1 Hz), total 4H], [3.62 (s) and 3.39 (s), total 2H], [2.90-2 .77 (m) and 2.61-2.48 (m), total 1H], 2.33 (s, 3H), 2.13-2.03 (m, 1H), 2.02-1.94 (m, 1H), 1.89-1.74 (m, 1H), [1.33 (d, d=6.7 Hz) and 1.28 (d, J=6.1 Hz), total 3H ]. Retention time: 2.77 min (Analytical conditions. Column: Chiral Technologies Chiralcel OJ-H, 4.6 x 100 mm, 5 µm; Mobile phase: 85:15 carbon dioxide/(methanol containing 0.2% ammonium hydroxide) ; Flow rate: 1.5 ml/min; Back pressure: 120 bar).

10 - Yield: 1.3 mg, 3.7 µmol, 6%. LCMS m/z 354.3 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.30-7.19 (m, 3H, presumably; partially hidden by solvent peak), 7.06-6.98 (m, 2H), [6.48 ( d, d=7.4 Hz) and 6.47 (d, J=7.4 Hz), total 1H], [3.75-3.55 (m) and 3.50-3.40 (m) , total 6H], 2.95-2.82 (m, 1H), 2.33 (s, 3H), [2.13-1.79 (m) and 1.74-1.66 (m, presumably ; partially hidden by the peak of water), total 4H], 1.36-1.30 (m, 3H). Retention time: 2.92 min (Analytical conditions identical to those used for 9).

11 - Yield: 1.3 mg, 3.7 µmol, 6%. LCMS m/z 354.3 [M+H] ⁺ . 1H NMR (400 MHz, chloroform-d) δ 7.29-7.21 (m, 2H, probable; partially hidden by solvent peak), 7.21-7.15 (m, 1H), 7.05-6, 93 (m, 2H), [6.48 (d, d=7.5 Hz) and 6.47 (d, J=7.5 Hz), total 1H], [3.74-3.52 (m ) and 3.45 (d, component of AB quartet, J=12.0 Hz), total 4H], [3.62 (s) and 3.39 (s), total 2H], [2.90-2, 78 (m) and 2.61-2.49 (m), total 1H], [2.33 (s) and 2.32 (s), total 3H], 2.10-2.04 (m, 1H ), 2.00-1.94 (m, 1H), 1.88-1.74 (m, 1H), [1.32 (d, J=6.7 Hz) and 1.28 (d, J =6.7 Hz), total 3H]. Retention time: 3.48 min (Analytical conditions identical to those used for 9).

12 - Yield: 2.1 mg, 5.9 µmol, 9%. LCMS m/z 354.3 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.29-7.20 (m, 3H, presumably; partially hidden by solvent peak), 7.06-6.98 (m, 2H), [6.48 ( d, J=7.4 Hz) and 6.46 (d, J=7.4 Hz), total 1H], [3.74-3.55 (m) and 3.50-3.40 (m) , total 6H], 2.95-2.82 (m, 1H), 2.32 (s, 3H), [2.12-1.78 (m) and 1.74-1.66 (m, presumably ; partially hidden by the peak of water), total 4H], 1.36-1.30 (m, 3H). Retention time: 4.14 min (Analytical conditions identical to those used for 9).

Based on comparison of ¹ H NMR data, 9 and 11 are enantiomers of each other. Likewise, 10 and 12 include a pair of enantiomers.

Example 13

(2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4 -dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one (13)

A solution of C68 (280 mg, 0.726 mmol) in dichloromethane (10 ml) was treated with trifluoroacetic acid (2 ml) and the reaction mixture was stirred at room temperature for 2 hours. The mixture was then concentrated in vacuo and evaporated twice from ethyl acetate to give the bare substrate as a dark brown oil (200 mg); part of this substance was used in the subsequent coupling reaction.

To a solution of P7 (36.4 mg, 0.183 mmol) in acetonitrile (3 ml) was added pyridinium trifluoromethanesulfonate (88.0 mg, 0.384 mmol), followed by the addition of 1,1'-carbonyldiimidazole (31.1 mg, 0.192 mmol). After stirring the mixture at room temperature for 45 minutes, a portion of the unprotected material from above (73 mg, ≤0.18 mmol) was added as a solution in acetonitrile (3 ml) and the reaction mixture was stirred at room temperature overnight. The mixture was then partitioned between dichloromethane and dilute aqueous ammonium chloride; the organic layer was washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. Silica gel chromatography (gradient: 0% to 10% methanol in dichloromethane) followed by supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IA, 21x250 mm, 5 µm; Mobile phase: 7:3 carbon dioxide/(0.5% ammonium hydroxide in methanol); Flow rate: 75 ml/min; Back pressure: 120 bar] gave (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5 -yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one (13). Yield: 13.6 mg, 29.1 µmol, approximately 16%. LCMS m/z 489.3 [M+Na ⁺ ]. Retention time: 2.6 min [Analytical conditions. Column: Chiral Technologies Chiralpak IA, 4.6x100 mm, 5 µm; Mobile phase: 65:35 carbon dioxide/(methanol containing 0.5% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar].

Example 14

(2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)-1-[(2S)-1-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one (14)

Pyridinium trifluoromethanesulfonate (1.02 g, 4.45 mmol) was added to a solution of P7 (substance from Step 2 of Alternative Preparation (#1) P7; 422 mg, 2.12 mmol) in acetonitrile (10 ml). To the resulting solution was added 1,1'-carbonyldiimidazole (360 mg, 2.22 mmol) in one portion and the reaction mixture was left stirring at room temperature for 45 minutes, then solution P28 (substance from step 2 of Preparation P28; 750 mg, 2) was added .12 mmol) in acetonitrile (5 ml) in one portion. The reaction mixture was stirred at room temperature for an additional 3 hours, then the mixture was diluted with saturated aqueous ammonium chloride and extracted three times with ethyl acetate. The combined organic layers were washed successively with saturated aqueous sodium bicarbonate and saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo; chromatography on silica gel (gradient: 30% to 100% ethyl acetate in heptane) gave (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-( pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one (14) as a white solid.

The indicated absolute stereochemistry was assigned based on single crystal X-ray diffraction analysis, which was performed on compound 14 obtained from crystallization of this batch (see below).

Yield: 670 mg, 1.45 mmol, 68%. LCMS m/z 463.4 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ [8.81 (d, J=4.9 Hz) and 8.80 (d, J=4.9 Hz), total 2H], [7.99 (d, J=1.6 Hz) and 7.98 (d, J=1.7 Hz), total 1H], [7.84 (s) and 7.81 (s), total 1H], [7 .30 (t, J=4.9 Hz) and 7.29 (t, J=4.9 Hz), total 1H], [6.78 (d, J=4.9 Hz) and 6.73 ( d, J=4.9 Hz), total 1H], [4.27 (sq., d=6.9 Hz) and 4.19 (sq., d=6.9 Hz), total 1H], [ 3.93-3.83 (m) and 3.76-3.67 (m), total 1H], [3.88 (s) and 3.88 (s), total 3H], [3.67- 3.57 (m), 3.53 (AV quartet, J _AB =12.3 Hz, Δν _AB =34.7 Hz) and 3.39 (d, component of the AB quartet, J = 10.6 Hz), total 3H], [2.94-2.72 (m) and 2.63-2.54 (m), total 2H], [2.57 (s) and 2.55 (s), total 3H], 2 .15-1.83 (m, 3H), 1.83-1.74 (m, 1H), [1.45 (d, J=6.8 Hz) and 1.43 (d, J=6, 8 Hz), total 3H].

Recrystallization from a 3:2 mixture of ethyl acetate and heptane gave a substance with a diastereomeric excess of 99.1%; further recrystallization from acetonitrile gave a single crystal, which was used for X-ray diffraction analysis.

Determination of structure 14 by single crystal X-ray diffraction

X-ray diffraction analysis of a single crystal

Data collection was carried out on a D8 Quest Bruker diffractometer at room temperature. Data collection consisted of omega and phi scans.

The structure was resolved by internal phasing using the SHELX software package in the P1 group of the triclinic class. The structure was then refined using the least squares method in the full matrix approximation. All non-hydrogen atoms were detected and refined using anisotropic displacement parameters.

Hydrogen atoms located on nitrogen were discovered from the Fourier difference map and refined with distance constraints. The remaining hydrogen atoms were placed in calculated positions and allowed to move on their carrier atoms. The final refinement included isotropic displacement parameters for all hydrogen atoms.

Absolute structure analysis using probability methods (Hooft, 2008) was performed using PLATON (Spek). The results show that the absolute structure is assigned correctly. This method calculates that the probability that the structure is assigned correctly is 100%. Hooft's parameter is given as 0.05 with esd (estimated standard deviation) being (10) and Parson's parameter is given as 0.04 with esd being (10).

The final R-index was 4.5%. The final difference Fourier map showed that there was no missing or shifted electron density.

Relevant information for crystal rocking, data collection, and structure refinement is summarized in Table A. Atomic coordinates, bond lengths, bond angles, and bias parameters are listed in Tables B through D.

Program and links

SHELXTL, Version 5.1, Bruker AXS, 1997.

PLATON, A.L. Speck, J. Appl. Christ. 2003, 36, 7-13.

MERCURY, C.F. Macrae, P.R. Edington, P. McCabe, E. Pidcock, G.P. Shields, R. Taylor, M. Towler and J. van de Streek, J. Appl. Christ. 2006, 39, 453-457.

OLEX2, O.V. Dolomanov, L.J. Bourhis, R. J. Gildea, J.A.K. Howard and H. Puschmann, J. Appl. Christ. 2009, 42, 339-341.

R.W.W. Hooft, L.H. Straver and A.L. Speck, J. Appl. Christ. 2008, 41, 96-103.

H.D. Flack, Acta Cryst. 1983, A39, 867-881.

Thus, the absolute stereochemistry of the compound of Example 14 was determined by single crystal X-ray diffraction analysis. Fig. 1 shows the X-ray diffraction single crystal structure (ORTEP image) of the crystalline compound of Example 14: (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-( pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one.

In some embodiments, the present invention provides a crystalline form of (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)- 3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one.

In certain other embodiments, the crystalline form of (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3, 4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one is the compound described (or prepared) in Example 14.

Alternative synthesis of Example 14

(2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one (14)

Step 1. Synthesis of tert-butyl-(2S)-6-(5,5-dimethyl-1,3,2-dioxaborinan-2-yl)-1-methyl-3,4-dihydro-1H-spiro[1, 8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate (C79).

Di(1-adamantyl)-n-butylphosphine (cataCXium® A; 2.21 g, 6.16 mmol), then palladium(II) acetate (0.461 mg, 2.05 mmol), was added to 2-methyltetrahydrofuran (170 ml ); the catalyst mixture was purged with argon for 10-20 minutes between each procedure. The mixture was heated at reflux for 1 hour, then cooled to ≤50°C.

In a separate reactor, P23 (98.2% w/w; 80.0 g, 205 mmol), 5,5,5',5'-tetramethyl-2,2'-bi-1,3,2-dioxaborinan (60 .3 g, 267 mmol), potassium acetate (97% w/w; 62.4 g, 617 mmol) and water (2.37 mL, 132 mmol) were added to 2-methyltetrahydrofuran (220 mL). The reactor walls were washed with 2-methyltetrahydrofuran (100 ml) and the resulting mixture was purged with argon for approximately 1 hour. The catalyst mixture was then added via cannula in less than 2 minutes and the reaction mixture was heated to reflux at 1°C/min. After 4 hours at reflux, the mixture was cooled to 10°C, kept at this temperature overnight and treated rapidly dropwise over 15 minutes with aqueous sodium hydroxide (1.0 M; 410 ml, 410 mmol). The internal temperature was kept below 17°C during the addition. The resulting mixture was heated to 20°C, diluted with tert-butyl methyl ether (180 ml) and mixed thoroughly for 5 minutes, after which it was confirmed that the aqueous layer had a pH of 10. An aqueous solution of sodium hydroxide (1.0 M) was added to the organic layer ; 480 ml, 480 mmol) in four portions over 4 minutes; after stirring for 5 minutes, the organic layer was separated and similarly extracted with aqueous sodium hydroxide (1.0 M; 480 ml, 480 mmol). The combined sodium hydroxide extracts were mixed with toluene (240 ml) and treated portionwise with hydrochloric acid (12.2 M; 62.3 ml, 760 mmol) at a rate that maintained the temperature below 30°C. The resulting mixture had a pH of 14; additional hydrochloric acid (12.2 M; 34 mL, 415 mmol) was added to adjust the pH to 10. After stirring the mixture for 5 minutes, the aqueous layer was extracted with toluene (2 x 240 mL) and the toluene layers were combined to give C79 as solution in toluene. The bulk of this substance was used in the next stage. Estimated yield: 73.2 g (quantitative NMR analysis), 176 mmol, 86% yield, as a solution in toluene.

Step 2. Synthesis of tert-butyl-(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]- 1'-carboxylate (C69).

To a solution of C79 in toluene (from the previous step; 509 ml containing 72.7 g, 175 mmol of C79) was added aqueous sodium hydroxide (1 M; 530 ml, 530 mmol) followed by the addition of 2-bromopyrimidine (39.0 g, 245 mmol). The resulting mixture was purged with argon for 30 minutes, then 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (Xantphos; 1.27 g, 2.19 mmol) and palladium(II) acetate (394 mg, 1. 76 mmol). After heating the reaction mixture at 50°C for 3.5 hours, the mixture was cooled to 20°C, left to stir overnight and filtered. The filter cake was washed with toluene (150 ml) and the organic layer of the combined filtrates was washed with water while stirring for 5 minutes and then the mixture was allowed to stand for 30 minutes; the solids in the mixture were maintained in an organic layer, which was subjected to molecular distillation at 100 mbar and 60°C. The mixture was distilled until approximately 275 ml remained, then the mixture was cooled to 20°C at a rate of 1°C/min. After stirring the mixture for 30 minutes, during which time solids were detected, heptane (727 ml) was slowly added dropwise over 30 minutes. The resulting solution was stirred for 10 minutes, heated to 60°C at a speed of 1°C/min and stirred at 60°C for 90 minutes, then the mixture was cooled to 20°C at a speed of 1°C/min and left to stir for 3 days. Filtration followed by washing the solid filter cake twice with filtrate and once with heptane (220 ml) provided C69 as a solid. Yield: 63.85 g, 167.4 mmol, 96%. HPLC purity: 99.4%. ¹ H NMR (600 MHz, DMSO-d ₆ ) δ 8.80 (d, J=4.8 Hz, 2H), 7.90 (s, 1H), 7.27 (t, J=4.8 Hz , 1H), [7.25 (br. s) and 7.24 (b. s), total 1H], 3.56-3.49 (m, 1H), 3.37-3.30 (m, 1H), 3.28-3.21 (m, 2H), 2.80-2.73 (m, 1H), 2.73-2.65 (m, 1H), 2.59 (s, 3H) , 1.99-1.84 (m, 2H), 1.82-1.69 (m, 2H), [1.41 (s) and 1.39 (s), total 9H].

Acquisition of X-ray powder diffraction (PXRD) data for crystalline C69

Sample C69 (obtained as described in step 2 above) was subjected to powder X-ray diffraction (PXRD) analysis and was found to be a crystalline substance.

Powder X-ray diffraction analysis was performed using a Bruker AXS D8 Endeavor diffractometer equipped with a copper (Cu) radiation source. The divergence slit was set to constant illumination of 15 mm. Diffracted radiation was detected by a PSD-Lynx Eye detector with the PSD detector slit set at 4.123 degrees. The X-ray tube voltage and current were set to 40 kV and 40 mA, respectively. In addition, an energy dispersive detector and a nickel filter were used. Data were collected on a Theta-Theta goniometer at Cu wavelengths from 3.0 to 40.0 degrees 2-theta using a step size of 0.0100 degrees and a step time of 1.0 seconds. The anti-scatter screen was installed at a fixed distance of 1.5 mm. Samples were prepared by placing them in a low-background silicone sample holder and rotating them at 15 rpm during collection. Data were collected using Bruker DIFFRAC Plus software and analysis was performed using EVA diffract plus software. The PXRD data file was not processed before peak searching. Using the peak finding algorithm in EVA software, peaks selected with a threshold value of 1 were used for preliminary peak assignment. To ensure accuracy, adjustments were made manually; the results of the automatic assignments were checked visually, and the peak positions were adjusted to the maximum of the peaks. Typically, peaks with relative intensity ≥3% were selected. Peaks that were not resolved or consistent with noise were generally not selected. Typical error associated with peak position from PXRD as specified in USP is up to +/- 0.2° 2-theta (USP-941).

One representative diffraction pattern was observed for the C69 crystalline form and is shown in FIG. 4. A list of diffraction peaks in degrees 2θ and relative intensities with a relative intensity of ≥3.0% PXRD from the crystalline C69 sample is shown in Table X-C69 below.

In some embodiments, the present invention provides a compound that is tert-butyl-(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin- 2,3'-pyrrolidine]-1'-carboxylate or its salt. In some embodiments, the present invention provides a compound that is tert-butyl-(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin- 2,3'-pyrrolidine]-1'-carboxylate. In certain other embodiments, the present invention provides a crystalline form of tert-butyl-(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2. 3'-pyrrolidine]-1'-carboxylate. In certain other embodiments, a crystalline form of tert-butyl-(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'- pyrrolidine]-1'-carboxylate exhibits a powder X-ray diffraction pattern including at least one characteristic peak expressed in degrees 2θ, such as shown in Table X-C69.

In some embodiments, a crystalline form of tert-butyl-(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ]-1'-carboxylate exhibits a powder X-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ, which are presented in Table X-C69. In some embodiments, a crystalline form of tert-butyl-(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ]-1'-carboxylate exhibits a powder X-ray diffraction pattern including at least three characteristic peaks expressed in degrees 2θ, which are presented in Table X-C69. In some embodiments, a crystalline form of tert-butyl-(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ]-1'-carboxylate exhibits a powder X-ray diffraction pattern including at least four (eg, 4, 5, 6, 7, 8, 9 or 10) characteristic peaks expressed in degrees 2θ, which are presented in Table X-C69. In some embodiments, a crystalline form of tert-butyl-(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ]-1'-carboxylate shows a powder X-ray diffraction pattern essentially as shown in FIG. 4.

Step 3. Synthesis of (2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] (P28, free base ).

A solution of C69 (96% by weight; 50.0 g, 126 mmol) in water (100 ml) and 2-propanol (150 ml) was added over 10 minutes to an 80°C mixture of water (150 ml) and concentrated sulfuric acid ( 14.5 ml, 272 mmol). After stirring the reaction mixture at 80°C for 4 hours, the mixture was cooled to 25°C and then subjected to molecular distillation at 120°C and atmospheric pressure. When the mixture reached a volume of approximately 200 ml as a result of distillation, the temperature was reduced to 50°C, activated carbon (Darco G-60; 10 g) was added and stirring was continued for 1.5 hours at 50°C. The mixture was then cooled to 25°C and filtered using a 10 μm filter. The filter cake was washed with water (100 ml) and the combined filtrates were diluted with 2-propanol (20 ml); the resulting mixture, pH 0.86, was made alkaline to cloud point, then clarified by adding 6 M aqueous sodium hydroxide (approximately 75 ml). The result was pH=9.32. The mixture was treated dropwise with additional 6 M aqueous sodium hydroxide (approximately 20 drops) until the pH was 9.6-9.7, at which point the turbidity remained. Stirring was continued for 45 minutes, then additional 6 M aqueous sodium hydroxide solution (total approximately 80 ml, 480 mmol) was added and stirring was continued at 20°C for 30 minutes. The mixture was then heated to 50°C at a rate of 1°C/min, stirred for 1.5 hours and cooled to 20°C at a rate of 1°C/min. After stirring for 1.5 hours, the mixture was filtered; the filter cake was washed with aqueous sodium hydroxide (1 M; 100 ml, 100 mmol) and dried overnight in vacuo at 50°C to obtain P28, the free base. Yield: 30.87 g, 98.1% P28 quantitated by NMR, 108 mmol, 86%. ¹ H NMR (600 MHz, DMSO-d ₆ ) δ 8.79 (d, J=4.8 Hz, 2H), 7.88 (s, 1H), 7.25 (t, J=4.8 Hz , 1H), 7.01 (s, 1H), 2.99 (ddd, J=11.0, 8.4, 6.4 Hz, 1H), 2.79 (ddd, J=10.9, 8 ,6, 5.6 Hz, 1H), 2.75-2.68 (m, 3H), 2.61 (d, J=11.3 Hz, 1H), 2.58 (s, 3H), 1 .80-1.68 (m, 3H), 1.65 (ddd, J=12.7, 8.6, 6.4 Hz, 1H).

Acquiring X-ray powder diffraction (PXRD) data for crystalline P28

Sample P28 (obtained as described in step 3 above) was subjected to powder X-ray diffraction (PXRD) analysis and was found to be a crystalline substance.

Powder X-ray diffraction analysis was performed using a Bruker AXS D8 Endeavor diffractometer equipped with a copper (Cu) radiation source. The divergence slit was set to constant illumination of 15 mm. Diffracted radiation was detected by a PSD-Lynx Eye detector with the PSD detector slit set at 4.123 degrees. The X-ray tube voltage and current were set to 40 kV and 40 mA, respectively. In addition, an energy dispersive detector and a nickel filter were used. Data were collected on a Theta-Theta goniometer at Cu wavelengths from 3.0 to 40.0 degrees 2-theta using a step size of 0.0100 degrees and a step time of 1.0 seconds. The anti-scatter screen was installed at a fixed distance of 1.5 mm. Samples were prepared by placing them in a low-background silicone sample holder and rotating them at 15 rpm during collection. Data were collected using Bruker DIFFRAC Plus software and analysis was performed using EVA diffract plus software. The PXRD data file was not processed before peak searching. Using the peak finding algorithm in EVA software, peaks selected with a threshold value of 1 were used for preliminary peak assignment. To ensure accuracy, adjustments were made manually; the results of the automatic assignments were checked visually, and the peak positions were adjusted to the maximum of the peaks. Typically, peaks with relative intensity ≥3% were selected. Peaks that were not resolved or consistent with noise were generally not selected. Typical error associated with peak position from PXRD as specified in USP is up to +/- 0.2° 2-theta (USP-941).

One representative diffraction pattern was observed for the P28 crystalline form and is shown in FIG. 5. A list of diffraction peaks in degrees 2θ and relative intensities with a relative intensity of ≥3.0% PXRD from the crystalline P28 sample are shown in Table X-P28 below.

In some embodiments, the present invention provides a compound that is (2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3' -pyrrolidine] or its salt. In some embodiments, the present invention provides a compound that is (2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3' -pyrrolidine]. In certain other embodiments, the present invention provides a crystalline form of (2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ]. In certain other embodiments, the crystalline form of (2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] exhibits a powder form an x-ray diffraction pattern including at least one characteristic peak expressed in degrees 2θ, such as shown in Table X-P28.

In some embodiments, the crystalline form of (2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] exhibits powder x-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ, which are presented in Table X-P28. In some embodiments, the crystalline form of (2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] exhibits powder x-ray diffraction pattern including at least three characteristic peaks expressed in degrees 2θ, which are presented in Table X-P28.

In some embodiments, the crystalline form of (2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] exhibits powder x-ray diffraction pattern including at least four (for example, 4, 5, 6, 7, 8, 9 or 10) characteristic peaks, expressed in degrees 2θ, which are presented in Table X-P28. In some embodiments, the crystalline form of (2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] exhibits powder x-ray diffraction pattern essentially the same as shown in FIG. 5.

Step 4. Synthesis of (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7'-methyl-6-(pyrimidin-2-yl)-3,4- Dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one (14).

A suspension of P7 (19.1 g, 95.9 mmol) in 2-methyltetrahydrofuran (200 ml) was treated with P28 free base (98.1% by weight, 25 g, 87.2 mmol), then N,N- diisopropylethylamine (19 ml, 110 mmol). Add 2,4,6-tripropyl-1,3,5,2,4,6-trioxatriphosphinane 2,4,6-trioxide (50% w/w solution in ethyl acetate; 65 mL, 110 mmol) over 15 minutes, at speed, which maintained the internal reaction temperature below 30°C. After stirring the reaction mixture for 100 minutes, aqueous sodium bicarbonate (1.14 M; 250 ml, 285 mmol) {Caution: gas evolution} was added and stirring was continued for 10 minutes at 20°C. The resulting mixture was heated to 40°C, stirred for 30 minutes and again treated with aqueous sodium bicarbonate (1.14 M; 125 ml, 142 mmol). After stirring the mixture for 80 minutes, water (75 ml) was added and stirring was continued for 10 minutes. The organic layer was distilled at 60°C and 500 mbar until the mixture was reduced to 5 volumes. 2-methyltetrahydrofuran (125 ml) was added, the temperature was adjusted to 45°C-50°C and the mixture was filtered through diatomaceous earth. Additional 2-methyltetrahydrofuran (50 ml) was used to wash the filter cake and the combined filtrates were distilled at 60° C. and 500 mbar to approximately 3 volumes. The temperature was increased to 80°C until solid particles settled to the bottom of the reactor, then decreased to 50°C. The resulting material was treated at 50°C for 15 minutes with heptane (250 ml) and left to stir at 50°C for 90 minutes. The mixture was then cooled to 20°C at a rate of 1°C/min and left to stir for 3 days, then the mixture was diluted to a volume of 600 ml by adding 10 mol% 2-methyltetrahydrofuran in heptane. Filtration yielded a filter cake, which was washed with heptane (75 ml) and dried overnight at 50°C in vacuo to give (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S )-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one (14) as a solid. Yield: 29.63 g, 64.06 mmol, 73%. HPLC purity: 100%. LCMS m/z 463.3 [M+H] ⁺ . ¹ H NMR (600 MHz, DMSO-d ₆ ) δ [8.81 (d, J=4.8 Hz) and 8.80 (d, J=4.7 Hz), total 2H], [8.12 (s) and 8.10 (s), total 1H], [7.90 (s) and 7.87 (s), total 1H], [7.33 (s) and 7.23 (s), total 1H], 7.30-7.26 (m, 1H), [6.75 (d, J=4.8 Hz) and 6.69 (d, J=4.8 Hz), total 1H], [ 4.15 (sq., J=6.9 Hz) and 4.10 (sq., J=6.9 Hz), total 1H], [3.83 (s) and 3.82 (s), total 3H], [3.78-3.71 (m), 3.61-3.49 (m), 3.47-3.41 (m), 3.42 (d, J=11.2 Hz) , 3.32-3.28 (m, presumably; partially hidden by the peak of water) and 3.25 (d, J=10.4 Hz), total 4H], [2.80-2.65 (m) and 2 .5-2.43 (m, presumably; partially hidden by solvent peak), 2H total], [2.59 (s) and 2.57 (s), 3H total], [2.03-1.94 (m ) and 1.87-1.72 (m), total 3H], 1.67-1.60 (m, 1H), 1.36-1.30 (m, 3H).

Acquisition of X-ray Powder Diffraction (PXRD) Data for Crystal Example 14

Sample of Example 14 (prepared essentially as described in this Alternative Synthesis Method, except that in step 4 the diatomaceous earth filtration was replaced by treating the mixture with SiliaMetS® Thiol followed by filtration. SiliaMetS® Thiol: Silicycle Inc., Product no. R51030B) was crushed and submitted for powder X-ray diffraction (PXRD) analysis and was found to be a crystalline substance (listed as Form I).

Powder X-ray diffraction analysis was performed using a Bruker AXS D8 Endeavor diffractometer equipped with a copper (Cu) radiation source. The divergence slit was set to constant illumination of 15 mm. Diffracted radiation was detected by a PSD-Lynx Eye detector with the PSD detector slit set at 4.123 degrees. The X-ray tube voltage and current were set to 40 kV and 40 mA, respectively. In addition, an energy dispersive detector and a nickel filter were used. Data were collected on a Theta-Theta goniometer at Cu wavelengths from 3.0 to 40.0 degrees 2-theta using a step size of 0.0100 degrees and a step time of 1.0 seconds. The anti-scatter screen was installed at a fixed distance of 1.5 mm. Samples were prepared by placing them in a low-background silicone sample holder and rotating them at 15 rpm during collection. Data were collected using Bruker DIFFRAC Plus software and analysis was performed using EVA diffract plus software. The PXRD data file was not processed before peak searching. Using the peak finding algorithm in EVA software, peaks selected with a threshold value of 1 were used for preliminary peak assignment. To ensure accuracy, adjustments were made manually; the results of the automatic assignments were checked visually, and the peak positions were adjusted to the maximum of the peaks. Typically, peaks with relative intensity ≥3% were selected. Peaks that were not resolved or consistent with noise were generally not selected. Typical error associated with peak position from PXRD as specified in USP is up to +/- 0.2° 2-theta (USP-941).

One representative diffraction pattern was observed for Form I of Example 14 and is shown in FIG. 1. A list of diffraction peaks in degrees 2θ and relative intensities with a relative intensity of ≥3.0% PXRD from the crystal sample of Example 14 are shown in Table XI below.

In some embodiments, the present invention provides a crystalline form of (2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)- 3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one. In certain other embodiments, the present invention provides a crystalline form of (2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl) -3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl]propan-1-one, which is listed as Form I.

In some embodiments, Form I (Example 14) exhibits a powder x-ray diffraction pattern including at least one characteristic peak, expressed in degrees 2θ, selected from 8.7±0.2°; 11.1±0.2°; and 13.3±0.2°. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least one characteristic peak, expressed in degrees 2θ, at 8.7±0.2°. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least one characteristic peak, expressed in degrees 2θ, at 11.1±0.2°. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least one characteristic peak, expressed in degrees 2θ, at 13.3±0.2°. In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; 11.1±0.2°; and 13.3±0.2°. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including two characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; and 11.1±0.2. In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least three characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; 11.1±0.2°; and 13.3±0.2°.

In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; 11.1±0.2°; and 26.0±0.2. In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; and 26.0±0.2°. In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ selected from 11.1±0.2°; and 26.0±0.2°. In some embodiments, Form I exhibits a powder X-ray diffraction pattern including at least three characteristic peaks expressed in degrees 2θ selected from 8.7±0.2°; 11.1±0.2°; and 26.0±0.2°.

In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least two characteristic peaks expressed in degrees 2θ, which are presented in Table XI. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least three characteristic peaks expressed in degrees 2θ, which are presented in Table XI. In some embodiments, Form I exhibits a powder x-ray diffraction pattern including at least four (eg, 4, 5, 6, 7, 8, 9, or 10) characteristic peaks expressed in degrees 2θ, which are presented in Table XI.

In some embodiments, Form I exhibits a powder x-ray diffraction pattern substantially as shown in FIG. 1.

Example 15

(2R)-2-(5-Chloro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one (15)

Step 1. Synthesis of tert-butyl-(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]- 1'-carboxylate (C69).

Mixture of 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi-1,3,2-dioxaborolane (249 mg, 0.981 mmol), P23 (250 mg, 0.654 mmol), bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (26.7 mg, 32.7 µmol) and oven-dried potassium acetate (257 mg, 2.62 mmol) in 1,4-dioxane ( 12 ml) was degassed by bubbling the mixture with nitrogen for 5 minutes. The reaction vessel was sealed and the mixture was heated to 100°C in an aluminum block for 2 hours, then allowed to cool to room temperature. 2-bromopyrimidine (109 mg, 0.686 mmol), dichlorobis(triphenylphosphine)palladium(II) (22.9 mg, 32.6 μmol) and degassed aqueous sodium carbonate (2.0 M; 0.817 ml, 1.63 mmol) and the mixture was heated at 90°C for 18 hours. After cooling to room temperature, the reaction mixture was diluted with ethyl acetate and filtered through diatomaceous earth. The organic layer of the filtrate was washed with saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo; chromatography on silica gel (eluents: 20%, then 50%, then 100% ethyl acetate in heptane) gave C69 as a white solid. Yield: 55.0 mg, 0.144 mmol, 22%. LCMS m/z 382.3 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.76 (d, J=4.8 Hz, 2H), 7.92 (s, 1H), 7.11 (t, J=4.9 Hz, 1H), 5.37 (b.s, 1H), 3.62-3.26 (m, 4H), 2.88-2.76 (m, 2H), 2.68 (s, 3H), 2 .06-1.77 (m, 4H), 1.46 (b.s, 9H).

Step 2. Synthesis of (2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine], dihydrochloride salt (P28 ).

A solution of hydrogen chloride in 1,4-dioxane (4.0 M; 0.144 ml, 0.576 mmol) was added to a solution of C69 (55.0 mg, 0.144 mmol) in a mixture of dichloromethane (0.5 ml) and 1,1,1, 3,3,3-hexafluoropropan-2-ol (0.5 ml) and the reaction mixture was stirred at room temperature for 2 hours, after which LCMS analysis showed conversion to P28: LCMS m/z 282.3 [M+H] ⁺ . The reaction mixture was concentrated in vacuo to give P28 as a yellow resinous substance. Yield: 50 mg, 0.141 mmol, 98%.

Step 3. Synthesis of (2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro -1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one (15).

Pyridinium trifluoromethanesulfonate (35.6 mg, 0.155 mmol) was added to a solution of P2 (16.7 mg, 77.4 μmol) in acetonitrile (1 ml). The resulting solution was treated with 1,1'-carbonyldiimidazole (12.6 mg, 77.7 μmol) in one portion and the reaction mixture was stirred at room temperature for 45 minutes. A solution of P28 (25.0 mg, 70.6 µmol) in acetonitrile (2 ml) was then added in one portion and stirring was continued at room temperature for 3 hours, then the reaction mixture was diluted with aqueous ammonium chloride and extracted three times with ethyl acetate. The combined organic layers were dried over magnesium sulfate, filtered and concentrated in vacuo. Purification by silica gel chromatography (gradient: 20% to 100% ethyl acetate in heptane), then supercritical fluid chromatography (Column: Chiral Technologies Chiralcel OJ-H, 21x250 mm, 5 µm; Mobile phase 9:1 carbon dioxide/(methanol, containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 150 bar) gave (2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[{2S) -7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one ( 15). Yield: 5.9 mg, 12 µmol, 17%. LCMS m/z 479.3 (observed chlorine isotope pattern) [M+H] ⁺ . ¹ H NMR (4 00 MHz, methanol-d ₄ ) δ [8.81 (d, J=5.0 Hz) and 8.81 (d, J=5.0 Hz), total 2H], [8, 15 (s) and 8.14 (s), total 1H], [7.85 (s) and 7.81 (s), total 1H], [7.31 (t, J=4.9 Hz) and 7.30 (t, J=4.9 Hz), total 1H], [6.81 (s) and 6.76 (s), total 1H], [4.32 (sq., J=7.0 Hz) and 4.23 (sq., J=6.9 Hz), total 1H], 3.91 (b.s, 3H), [3.9-3.83 (m) and 3.76-3 .52 (m), 3H total], [3.49 (d, J=12.2 Hz) and 3.38-3.3 (m, presumably; partially hidden by the solvent peak), 1H total], [2, 93-2.72 (m) and 2.56-2.47 (m), total 2H], [2.57 (s) and 2.56 (s), total 3H], [2.16-2, 07 (m) and 2.05-1.84 (m), total 3H], 1.80-1.73 (m, 1H), [1.43 (d, J=6.9 Hz) and 1, 42 (d, J=6.9 Hz), total 3H].

Alternative step 3. Synthesis of (2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4- dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one (15) to determine the crystal structure by X-ray diffraction.

Pyridinium trifluoromethanesulfonate (112 mg, 0.487 mmol) was added to a solution of P2 (substance from Preparations P2 and P3; 50.0 mg, 0.232 mmol) in acetonitrile (3 ml). The resulting solution was treated with 1,1'-carbonyldiimidazole (39.5 mg, 0.244 mmol) in one portion and the reaction mixture was stirred at room temperature for 30 minutes. Solution P28 (82.1 mg, 0.232 mmol) was then added in one portion; after 1 hour, a drop of water was added to obtain a solution. After stirring the reaction mixture at room temperature for 2 hours, LCMS analysis showed a conversion of 15: LCMS m/z 479.3 (observed chlorine isotope pattern) [M+H] ⁺ . The reaction mixture was then partitioned between ethyl acetate and aqueous sodium bicarbonate; the organic layer was washed successively with water and saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 10% methanol in dichloromethane) gave (2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-( pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one (15) as a solid. Yield: 102 mg, 0.213 mmol, 92%.

This material was dissolved in a mixture (approximately 12 ml) of 10% ethyl acetate in heptane by heating. The solution was allowed to cool and then stand, partially covered, at room temperature for 3 days. The resulting solid provided a crystal for X-ray diffraction analysis (see below).

Determination of the structure of 15 by single crystal X-ray diffraction

X-ray diffraction analysis of a single crystal

Data collection was carried out on a Bruker D8 Venture diffractometer at room temperature. Data collection consisted of omega and phi scans. The micro-sized and multi-domain type crystalline material used showed theta diffraction above the resolution range of 0.90-0.94 A.

The structure was resolved by internal phasing using the SHELX software package in the P1 space group of the triclinic class. The structure was then refined using the least squares method in the full matrix approximation. All non-hydrogen atoms were detected and refined using anisotropic displacement parameters.

Hydrogen atoms located on nitrogen were discovered from the Fourier difference map and refined with distance constraints. The remaining hydrogen atoms were placed in calculated positions and allowed to move on their carrier atoms. The final refinement included isotropic displacement parameters for all hydrogen atoms.

Absolute structure analysis using probability methods (Hooft, 2008) was performed using PLATON (Spek). The results show that the absolute structure is assigned correctly. This method calculates that the probability that the structure is assigned correctly is 100%. Hooft's parameter is given as 0.04 with esd (estimated standard deviation) being (3) and Parson's parameter is given as 0.05 with esd being (3).

The final R-index was 6.9%. The final difference Fourier map showed that there was no missing or shifted electron density.

Relevant information for crystal rocking, data collection, and structure refinement is summarized in Table E. Atomic coordinates, bond lengths, and bias parameters are listed in Tables F-H.

Program and links

See the list above for Structure Determination 14 by Single Crystal X-Ray Diffraction.

Used symmetry transformations to obtain equivalent atoms

Thus, the absolute stereochemistry of the compound of Example 15 was determined by single crystal X-ray diffraction analysis. Fig. 2 shows the X-ray diffraction single crystal structure (ORTEP image) of the crystalline compound of Example 15: (2R)-2-(5-Chloro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-( pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one.

In some embodiments, the present invention provides a crystalline form of (2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)- 3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one. In certain other embodiments, the crystalline form of (2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3, 4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one is the compound described (or prepared) in Example 15.

Examples 16 and 17

(2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1 (16) and (2R)-2-(5-Fluoro-2-methoxypyridin- 4-yl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ]-1'-yl]propan-1-one, DIAST-2 (17)

Step 1. Synthesis of tert-butyl-7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine ]-1'-carboxylate (C80).

Mixture P22 (100 mg, 0.262 mmol), 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (109 mg, 0.524 mmol) , a complex of bis(diphenylphosphino)ferrocene]dichloropalladium(II) with dichloromethane (10.7 mg, 13.1 μmol) and an aqueous solution of sodium carbonate (2.0 M; 0.33 ml, 0.66 mmol) in 1.4 -dioxane (3 ml) was purged with nitrogen. The reaction vessel was sealed and heated to 80°C overnight, then LCMS analysis showed conversion to C80: LCMS m/z 384.3 [M+H] ⁺ . The reaction mixture was cooled to room temperature, then the mixture was partitioned between ethyl acetate and water, and the aqueous layer was extracted twice with ethyl acetate. The combined organic layers were washed with saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and purified by silica gel chromatography (gradient: 0% to 100% ethyl acetate in heptane) to give C80 as a solid. Yield: 93 mg, 0.24 mmol, 92%. ^1H NMR (400 MHz, chloroform-d), characteristic peaks: δ 7.52 (s, 1H), 7.36 (s, 1H), 7.19 (s, 1H), 3.95 (s, 3H ), 3.62-3.26 (m, 4H), 2.85-2.68 (m, 2H), 2.41 (s, 3H), [1.47 (s) and 1.45 (s ), total 9H].

Step 2. Synthesis of 7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine], bis- trifluoroacetate salt (C81).

Trifluoroacetic acid (1.0 ml) was added to a solution of C80 (92 mg, 0.24 mmol) in dichloromethane (3 ml) and the reaction mixture was stirred at room temperature for 2 hours. The mixture was then concentrated in vacuo and the residue was co-evaporated twice with ethyl acetate/heptane to obtain C81 as a gum. Yield: 128 mg, estimated quantitative. LCMS m/z 284.2 [M+H] ⁺ .

Step 3. Synthesis of (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4 -dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1 (16) and (2R)-2-(5-fluoro- 2-methoxypyridin-4-yl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2, 3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-2 (17).

To a solution of P7 (23.9 mg, 0.120 mmol) in acetonitrile (1 ml) was added pyridinium trifluoromethanesulfonate (57.8 mg, 0.252 mmol), followed by the addition of 1,1'-carbonyldiimidazole (20.4 mg, 0.126 mmol). The reaction mixture was stirred at room temperature for 45 minutes, then a solution of C81 (34.0 mg, 66.5 μmol) in acetonitrile was added and stirring was continued overnight at room temperature. LCMS analysis at this point showed the presence of the combination product: LCMS m/z 465.3 [M+H] ⁺ . The reaction mixture was then partitioned between dichloromethane and dilute aqueous ammonium chloride; the organic layer was washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. Purification was carried out by chromatography on silica gel (gradient: 0% to 10% methanol in dichloromethane), then supercritical fluid chromatography (Column: Phenomenex Lux Cellulose-1, 21x250 mm, 5 μm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar] The first eluting diastereomer was reported as 16 {(2R)-2-(5-fluoro-2-methoxypyridine-4- yl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]- 1'-yl]propan-1-one, DIAST-1}, and the second eluting diastereomer as 17 {(2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[7-methyl- 6-(1-methyl-1H-pyrrolidin)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one ,DIAST-2}.

16 - Yield: 7.3 mg, 15.7 µmol, 24%. LCMS m/z 465.5 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ [7.99 (d, J=1.6 Hz) and 7.97 (d, J=1.7 Hz), total 1H], [7.67 (s) and 7.67 (s), total 1H], 7.55-7.52 (m, 1H), [7.29 (s) and 7.27 (s), total 1H], [6, 78 (d, J=4.9 Hz) and 6.72 (d, J=4.9 Hz), total 1H], [4.27 (sq., J=6.9 Hz) and 4.18 ( sq., J=6.9 Hz), total 1H], [3.92 (s) and 3.92 (s), total 3H], [3.88 (s) and 3.88 (s), total 3H], [3.88-3.83 (m), 3.75-3.56 (m) and 3.54 (d, AB quartet component, J=12.1 Hz), total 3H], [3 .45 (d, AB quartet component, J=12.3 Hz) and 3.36 (d, J=10.6 Hz), total 1H], [2.89-2.70 (m) and 2.59 -2.49 (m), total 2H], [2.37 (s) and 2.34 (s), total 3H], 2.13-1.81 (m, 3H), 1.80-1, 71 (m, 1H), 1.47-1.40 (m, 3H). Retention time: 3.71 minutes [Analytical conditions. Column: Phenomenex Lux Cellulose-1, 4.6x100 mm, 5 µm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 200 bar].

17 - Yield: 6.2 mg, 13.3 µmol, 20%. LCMS m/z 466.6 [M+H] ⁺ . Retention time: 4.64 min (Analytical conditions identical to those used for 16).

Example 18

(2R)-2-(5-Fluoro-2-methoxypyridin-4-yl)-1-{(2S)-7-methyl-6-[( ^4,6-2H2 ₎ pyrimidin-2-yl]- 3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl}propan-1-one (18)

Stage 1. Synthesis of ( ^4,6-2H2 ) _pyrimidin -2-amine (C82).

To a solution of 4,6-dichloropyrimidin-2-amine (500 mg, 3.05 mmol) in methanol-d ₄ (10 ml) was added palladium on carbon (100 mg) and triethylamine (1.3 ml, 9.3 mmol) . The reaction mixture was stirred under deuterium gas at 20°C for 6 hours, then the mixture was filtered to remove the catalyst. The collected catalyst was washed with methanol (2×10 ml), then the combined filtrates were concentrated in vacuo, then chromatographed on silica gel (gradient: 0% to 80% ethyl acetate in petroleum ether) to obtain C82 as a white solid. Yield: 210 mg, 2.16 mmol, 71%. LCMS m/z 98.2 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ 6.60-6.52 (b.s, 2H), 6.53 (s, 1H).

Stage 2. Synthesis _of 2-chloro( ^4,6-2H2 )pyrimidine (C83).

Intermediate C82 (210 mg, 2.16 mmol) was added portionwise to concentrated hydrochloric acid (0.7 mL) at 0° C. and the resulting mixture was stirred until homogeneous. The solution was then cooled to about -15°C, then a cooled solution of sodium nitrite (298 mg, 4.32 mmol) in water (0.5 ml) was added dropwise over 1 hour, maintaining the reaction temperature between -15°C and - 10°C. The reaction mixture was stirred for 1 hour and the temperature was allowed to rise to about -5°C; the mixture was then carefully neutralized to pH 7 by adding 30% aqueous sodium hydroxide while maintaining the reaction temperature below 0°C. The resulting mixture was extracted with diethyl ether (3×5 ml) and the combined organic layers were washed with saturated aqueous sodium chloride (10 ml), dried over sodium sulfate, filtered and concentrated in vacuo to give C83 as a white solid. Yield: 115 mg, 0.987 mmol, 46%. ^1H NMR (400 MHz, DMSO- _d6 ) δ 7.60 (s, 1H).

Step 3. Synthesis of tert-butyl-(2S ₎ -7-methyl-6-[( ^4,6-2H2 )pyrimidin-2-yl]-3,4-dihydro-1H-spiro[1,8-naphthyridine -2,3'-pyrrolidine]-1'-carboxylate (C84).

A mixture of C83 (40 mg, 0.34 mmol), P27 (119 mg, 0.34 mmol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (SPhos; 5.6 mg, 14 μmol), chloro(2- dicyclohexylphosphino-2',6'-dimethoxy-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(II) (SPhos Pd G2; 4.9 mg, 6. 8 µmol) and an aqueous solution of lithium hydroxide (2 M; 0.4 ml, 0.8 mmol) in tetrahydrofuran (5 ml) were purged with nitrogen for 3 minutes, then the reaction mixture was stirred at 60°C for 4 hours. The mixture was then concentrated in vacuo; the residue was purified by chromatography on silica gel (gradient: 0% to 50% ethyl acetate in petroleum ether) to give C84 as a yellow solid. Yield: 116 mg, 0.302 mmol, 89%. LCMS m/z 384.3 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ [8.04 (s) and 8.01 (s), total 1H], 7.14 (s, 1H), 3.67-3.30 (m, 4H), 2.92-2.76 (m, 2H), [2.74 (s) and 2.73 (s), total 3H], 2.12-1.79 (m, 4H), [1 .47 (s) and 1.46 (s), total 9H].

Step 4. Synthesis of (2S)-7-methyl-6-[( ^4,6-2H2 )pyrimidin-2- _yl ]-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3 '-pyrrolidine], dihydrochloride salt (C85).

A solution of hydrogen chloride in 1,4-dioxane (4 M; 3 ml) was added to a solution of C84 (116 mg, 0.302 mmol) in dichloromethane (3 ml) and the reaction mixture was stirred at 20°C for 2 hours. Concentration in vacuo gave C85 as a yellow solid. Yield: 108 mg, 0.303 mmol, quantitative. LCMS m/z 284.2 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ 10.09-9.93 (b.s, 1H), 9.82-9.67 (b.s, 1H), 9.01 (s, 1H ), 8.45 (s, 1H), 7.50 (s, 1H), 3.50-3.34 (m, 2H), 3.34-3.27 (m, 2H), 3.01- 2.84 (m, 2H), 2.82 (s, 3H), 2.26-2.07 (m, 3H), 1.99-1.87 (m, 1H).

_Step 5. Synthesis of (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-{(2S)-7-methyl-6-[( ^4,6-2H2 )pyrimidin-2 -yl]-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl}propan-1-one (18).

Solution C85 (80 mg, 0.22 mmol), P7 (45 mg, 0.23 mmol), fluoro-N,N,N',N'-bis(tetramethylene) formamidinium hexafluorophosphate (BTFFH; 85 mg, 0.27 mmol) and pyridine (71 mg, 0.890 mmol) in dichloromethane (10 ml) were stirred at 25°C for 16 hours. The reaction mixture was poured into aqueous sodium bicarbonate (10 ml), then the mixture was extracted with ethyl acetate (2×20 ml); the combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 10% methanol in dichloromethane) gave (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-{(2S)-7-methyl-6-[ ( ^4,6-2H2 )pyrimidin-2-yl]-3,4-dihydro-1H-spiro[1,8- _naphthyridin -2,3'-pyrrolidin]-1'-yl}propan-1-one (18) as a white solid. Yield: 27 mg, 58 µmol, 26%. LCMS m/z 465.3 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ [8.00 (d, J=1.7 Hz) and 7.98 (d, J=1.7 Hz), total 1H], [7.85 (s) and 7.82 (s), total 1H], [7.31 (s) and 7.30 (s), total 1H], [6.78 (d, J=4.9 Hz) and 6 .73 (d, J=4.9 Hz), total 1H], [4.28 (sq., J=6.9 Hz) and 4.20 (sq., J=6.9 Hz), total 1H ], [3.93-3.85 (m), 3.77-3.67 (m), 3.67-3.57 (m), 3.53 (AB quartet, J _AB =12.2 Hz , Δν _AB =35.5 Hz) and 3.39 (d, J=10.6 Hz), total 4H], [3.89 (s) and 3.88 (s), total 3H], [2, 95-2.75 (m) and 2.64-2.55 (m), total 2H], [2.58 (s) and 2.55 (s), total 3H], [2.16-2, 06 (m) and 2.05-1.85 (m), total 3H], 1.84-1.75 (m, 1H), [1.45 (d, J=6.9 Hz) and 1, 44 (d, J=6.9 Hz), total 3H].

Examples 19 and 20

2-(4-Fluorophenyl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3 '-pyrrolidin]-1'-yl]ethan-1-one, ENT-1 (19) and 2-(4-Fluorophenyl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4 -yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl]ethan-1-one, ENT-2 (20)

Step 1. Synthesis of 1-(1-benzyl-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl)-2-(4- fluorophenyl)ethan-1-one (C86).

Trifluoroacetic acid (319 mg, 2.80 mmol) was added to a solution of P30 (110.0 mg, 0.280 mmol) in dichloromethane (4 ml) and the reaction mixture was stirred at room temperature for 2 hours. The mixture was then concentrated in vacuo, co-evaporated with ethyl acetate several times and dissolved in dichloromethane (4 ml). The resulting solution was treated with triethylamine (84.9 mg, 0.839 mmol). O-(7-azabenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU; 117 mg, 0.308 mmol) and (4-fluorophenyl)acetic acid (43.1 mg, 0.280 mmol) and stirred overnight at room temperature. After removal of the solvent in vacuo, the residue was purified by silica gel chromatography (gradient: 0% to 10% methanol in dichloromethane) to give C86 as a light tan solid. Yield: 120 mg, 0.279 mmol, quantitative. ^1H NMR (400 MHz, chloroform-d) δ [7.31-7.13 (m), 7.13-7.06 (m) and 7.05-6.91 (m), total 10H], 6.44-6.38 (m, 1H), 5.11-4.97 (m, 1H), [4.88 (d, AB quartet component, J=16.8 Hz) and 4.77 (d , AB quartet component, J=16.7 Hz), total 1H], [3.71-3.60 (m), 3.59-3.37 (m) and 3.33-3.24 (m) , total 6H], [2.83-2.69 (m) and 2.62-2.51 (m), total 2H], 2.35-2.17 (m, 1H), [2.24 ( s) and 2.23 (s), total 3H], 2.01-1.68 (m, 3H).

Step 2. Synthesis of 1-(1-benzyl-6-bromo-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl)-2 -(4-fluorophenyl)ethan-1-one (C87).

1,3-Dibromo-5,5-dimethylimidazolidine-2,4-dione (47.9 mg, 0.168 mmol) was added in several small portions to a 0°C solution of C86 (120 mg, 0.279 mmol) in dichloromethane (5 ml). The reaction mixture was allowed to warm to room temperature; after 30 minutes, LCMS analysis showed the presence of C87: LCMS m/z 508.3 (observed bromine isotope pattern) [M+H] ⁺ . After 1 hour, the reaction mixture was concentrated in vacuo and chromatographed on silica gel (gradient: 0% to 100% ethyl acetate in heptane) to give C87. Yield: 65.0 mg, 0.128 mmol, 46%. ^1H NMR (400 MHz, chloroform-d) δ [7.35-7.17 (m), 7.16-7.06 (m) and 7.05-6.91 (m), total 10H], [4.98 (d, AB quartet component, J=16.7 Hz) and 4.98 (d, AB quartet component, J=16, 8 Hz), total 1H], [4.80 (d, AB component quartet, J=16.8 Hz) and 4.72 (d, component AB quartet, J=16.7 Hz), total 1H], [3.72-3.62 (m), 3.58-3, 43 (m) and 3.33-3.24 (m), total 6H], [2.85-2.69 (m) and 2.62-2.48 (m), total 2H], 2.38 -2.15 (m, 1H), [2.34 (s) and 2.32 (s), total 3H], 2.01-1.70 (m, 3H).

Step 3. Synthesis of 1-[1-benzyl-7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3 '-pyrrolidin]-1'-yl]-2-(4-fluorophenyl)ethan-1-one (C88).

The reaction vessel was loaded with C87 (65.0 mg, 0.128 mmol), 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (33 .1 mg, 0.159 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (5.20 mg, 6.37 µmol), aqueous solution of sodium carbonate (2.0 M; 0.127 ml, 0.254 mmol) and 1,4-dioxane (3 ml). The vessel was purged with nitrogen, then the mixture was sealed and heated at 90°C overnight, after which LCMS analysis showed conversion to C88: LCMS m/z 510.4 [M+H] ⁺ . The reaction mixture was then cooled to room temperature and partitioned between ethyl acetate and aqueous ammonium chloride. The aqueous layer was extracted twice with ethyl acetate and the combined organic layers were washed with saturated aqueous sodium chloride, dried over magnesium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (gradient: 0% to 10% methanol in dichloromethane) gave C88 as a solid. Yield: 65.0 mg, 0.128 mmol, quantitative.

Step 4. Synthesis of 2-(4-fluorophenyl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine -2,3'-pyrrolidin]-1'-yl]ethan-1-one, ENT-1 (19) and 2-(4-fluorophenyl)-1-[7-methyl-6-(1-methyl-1H -pyrazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl]ethan-1-one, ENT-2 (20).

A solution of boron tribromide in dichloromethane (1.0 M; 0.765 ml, 0.765 mmol) was added to a -78°C solution of C88 (65.0 mg, 0.128 mmol) in dichloromethane (3 ml), then the reaction mixture was allowed to warm to room temperature and stirred for 15 hours. The mixture was then treated with methanol (0.5 ml) and concentrated in vacuo. Separation into the constituent enantiomers was carried out using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak AS-H, 21×250 mm, 5 μm; Mobile phase: 83:7 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 200 bar]. The first eluting diastereomer was reported as 19 {2-(4-fluorophenyl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H-spiro[1 ,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]ethan-1-one, ENT-1}, and the second eluting diastereomer as 20 {2-(4-fluorophenyl)-1-[7-methyl -6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]ethane-1- he, ENT-2}.

19 - Yield: 3.8 mg, 9.1 µmol, 7%. LCMS m/z 442.5 [M+Na ⁺ ]. Retention time: 2.88 min [Analytical conditions. Column: Chiral Technologies Chiralpak AS-H, 4.6×100 mm, 5 µm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 200 bar].

20 - Yield: 2.0 mg, 4.8 µmol, 4%. LCMS m/z 442.5 [M+Na ⁺ ]. Retention time: 4.01 min (Analytical conditions identical to those used for 19).

1. The reaction of 5-bromo-2-iodopyrimidine with P27 was carried out using [1,1'-bis(diphenylphosphino)ferrocene] dichloropalladium (II) and sodium carbonate to obtain the desired tert-butyl-(2S)-6-(5- bromopyrimidin-2-yl)-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidine]-1'-carboxylate.

2. Deprotection of compound P17 using hydrogen chloride in 2-propanol gave the desired 7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine].

3. Separation of the product into its four constituent diastereomers was carried out by supercritical fluid chromatography as follows: Initial separation was carried out [Column: Chiral Technologies Chiralcel OJ, 30×250 mm, 5 μm; Mobile phase: 9:1 carbon dioxide/(2-propanol containing 0.2% 1-aminopropan-2-ol); Flow rate: 80 ml/min; Back pressure: 100 bar] to obtain a first elution mixture (Pdt1) and a second elution mixture (Pdt2). Retention time for Pdtl: 3.8 0 min [Analytical conditions. Column: Chiral Technologies Chiralcel OJ, 4.6x250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: 2-propanol containing 0.2% 1-aminopropan-2-ol; Gradient: 5% B for 1.00 minutes, then 5% to 60% B for 8.00 minutes; Flow rate: 3.0 ml/min; Back pressure: 120 bar]. Retention time for Pdt2: 4.08 min (Analytical conditions identical to those used for Pdt1).

Pdt1 was then separated {Column: Phenomenex Lux Amylose-1, 30×250 mm, 5 µm; Mobile phase: 3:2 carbon dioxide/[(1:1 acetonitrile:methanol) containing 0.2% (7 M ammonia in methanol)]; Flow rate: 80 ml/min; Back pressure: 100 bar). The first eluting diastereomer was designated as Example 23 and the second eluting diastereomer as Example 24.

Pdt2 was separated {Column: Phenomenex Lux Amylose-1, 30×250 mm, 5 µm; Mobile phase: 7:3 carbon dioxide/[ethanol containing 0.2% (7 M ammonia in methanol)]; Flow rate: 80 ml/min; Back pressure: 100 bar) to obtain the first eluting diastereomer of Example 25 and the second eluting diastereomer of Example 26.

4. Analytical conditions. Column: Phenomenex Lux Amylose-1, 4.6×250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: (1:1 acetonitrile/methanol) containing 0.2% (7 M ammonia in methanol); Gradient: 5% B for 1.00 minutes, then 5% to 60% B for 8.00 minutes; Flow rate: 3.0 ml/min; Back pressure: 120 bar.

5. These LCMS data were obtained from analysis of the reaction mixture.

6. Analytical conditions. Column: Phenomenex Lux Amylose-1, 4.6×250 mm, 5 µm; Mobile phase A: carbon dioxide; Mobile phase B: ethanol containing 0.2% (7 M ammonia in methanol)]; Gradient: 5% B for 1.00 minutes, then 5% to 60% B for 8.00 minutes; Flow rate: 3.0 ml/min; Back pressure: 120 bar.

7. Desired tert-butyl-(2S)-7-methyl-6-[2-methyl-1-(trifluoromethyl)-1H-imidazol-4-yl]-3,4-dihydro-1H-spiro[1,8 α-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate was synthesized from P23 using the method described in Preparation of P28 for the synthesis of C69; 4-iodo-2-methyl-1-(trifluoromethyl)-1H-imidazole was used instead of 2-bromopyrimidine.

8. [(2R)-1'-(tert-Butoxycarbonyl)-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-6-yl]boronic acid prepared from p24 using the method described in Preparation of P27. Subsequent conversion to the desired tert-butyl-(2R)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]- The 1'-carboxylate was carried out in the same manner as the synthesis of C84 from P27 in Example 18.

9. Deprotection of compound c66 using hydrogen chloride in dichloromethane gave the desired {2R)-1-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H-spiro[1, 8-naphthyridine-2,3'-pyrrolidine].

10. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 30×250 mm, 5 μm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 80 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was specified as Example 31 and the second eluting diastereomer as Example 32. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 4.6×250 mm, 5 μm; Mobile phase A: carbon dioxide; Mobile phase B: methanol containing 0.2% (7 M ammonia in methanol); Gradient: 5% B for 1.00 minutes, then 5% to 60% B for 8.00 minutes; Flow rate: 3.0 ml/min; Back pressure: 120 bar] Example 31 showed a retention time of 4.22 minutes. Example 32 had a retention time of 4.4 8 minutes under the same conditions.

11. Comparison of the ¹ H NMR spectra showed that Example 31 is the enantiomer of Example 4 and Example 32 is the enantiomer of Example 3.

12. Conversion of C44 to 1'-benzyl-7-methyl-6-(2-methyl-1,3-oxazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2, 3'-pyrrolidine] was carried out using the method described for the synthesis of C48 in Preparations P17 and P18, except that 2-chloro-3-iodo-6-methyl-5-(2-methyl-1,3-oxazole) was used -4-yl)pyridine instead of C40. Subsequent hydrogenation gave the desired 7-methyl-6-(2-methyl-1,3-oxazol-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine].

13. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 20×250 mm, 5 μm; Mobile phase: 78:22 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 50 ml/min]. The first eluting diastereomer was specified as Example 34 and the second eluting diastereomer as Example 35. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-3R, 3.0×150 mm, 3 μm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 2.5 ml/min] Example 34 showed a retention time of 2.63 minutes. Example 35 had a retention time of 3.36 minutes under the same conditions.

14. The product was separated into its constituent diastereomers using HPLC (Column: Chiral Technologies Chiralpak AD, 50x250 mm, 10 µm; Mobile phase: 95:5:0.1 ethanol/acetonitrile/diethylamine; Flow rate: 60 ml/min ). The first eluting diastereomer was specified as Example 36 and the second eluting diastereomer as Example 37. When performing analytical HPLC (Column: Chiral Technologies Chiralpak AD-H, 4.6×150 mm, 5 µm; Mobile phase: 95:5:0, 1 ethanol/acetonitrile/diethylamine; Flow rate: 0.8 ml/min), Example 36 showed a retention time of 5.04 min. Example 37 had a retention time of 7.8 9 minutes under the same conditions.

15. Conversion of 5-chloro-4-iodo-2-(trifluoromethyl)pyridine to the desired 2-[5-chloro-2-(trifluoromethyl)pyridin-4-yl]propanoic acid was carried out using the method described in Preparation P5. LCMS m/z 254.0 (observed chlorine isotope pattern) [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.72 (s, 1H), 7.83 (s, 1H), 4.27 (q.v., J=7.3 Hz, 1H), 1, 57 (d, J=7.3 Hz, 3H).

16. The product was separated into its constituent diastereomers using HPLC (Column: Chiral Technologies Chiralpak AY, 50x250 mm, 10 µm; Mobile phase: 60:40:0.1 hexane/ethanol/diethylamine; Flow rate: 60 ml/min ). The first eluting diastereomer was specified as Example 38 and the second eluting diastereomer as Example 39. When performing analytical HPLC (Column: Chiral Technologies Chiralpak AD-H, 4.6×150 mm, 5 μm; Mobile phase: methanol; Flow rate: 1 .0 ml/min), Example 38 showed a retention time of 3.53 minutes. Example 39 had a retention time of 5.4 6 minutes under the same conditions.

17. Conversion of 4-iodo-2-methoxy-5-(trifluoromethyl)pyridine to the desired 2-[2-methoxy-5-(trifluoromethyl)pyridin-4-yl]propanoic acid was carried out using the method described in Preparation P5. LCMS m/z 250.1 [M+H] ⁺ . ^1H NMR (4 00 MHz, chloroform-d) δ 8.46 (s, 1H), 6.88 (s, 1H), 4.10 (q.v., J=7.1 Hz, 1H), 4, 00 (s, 3H), 1.54 (d, J=7.0 Hz, 3H).

18. The product was separated into its constituent diastereomers using HPLC (Column: Chiral Technologies Chiralpak IA, 50x250 mm, 10 µm; Mobile phase: 70:30:0.1 hexane/ethanol/diethylamine; Flow rate: 60 ml/min ). The first eluting diastereomer was specified as Example 40 and the second eluting diastereomer as Example 41. When performing analytical HPLC (Column: Chiral Technologies Chiralpak IA-3, 4.6×250 mm, 3 μm; Mobile phase: 70:30:0, 1 hexane/ethanol/diethylamine; Flow rate: 1.0 ml/min), Example 40 showed a retention time of 6.49 minutes. Example 41 had a retention time of 8.3 9 minutes under the same conditions.

19. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 20×250 mm, 5 µm; Mobile phase: 7:3 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 50 ml/min]. The first eluting diastereomer was specified as Example 42 and the second eluting diastereomer as Example 43. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-3R, 3.0×150 mm, 3 μm; Mobile phase: 7:3 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 2.5 ml/min], Example 42 showed a retention time of 1.81 min. Example 43 had a retention time of 2.54 minutes under the same conditions.

20. 6-Chloro-2-methylpyrimidin-4-ol was converted to 4-chloro-6-(difluoromethoxy)-2-methylpyrimidine using the method described in Preparation P11, Step 1. This material was then used to obtain the desired 2-[ Lithium 6-(difluoromethoxy)-2-methylpyrimidin-4-yl]propanoate according to the method presented in Preparation P4. LCMS m/z 233.1 [M+H] ⁺ . ¹ H NMR (4 00 MHz, methanol-d ₄ ) δ 7.62 (t, J _HF = 72.1 Hz, 1 H), 6.83 (s, 1 H), 3.70 (sq., J = 7 .2 Hz, 1H), 2.58 (s, 3H), 1.48 (d, J=7.2 Hz, 3H).

21. The product was separated into its constituent diastereomers using HPLC (Column: Chiral Technologies Chiralpak IA 4.6 cm x 25 mm; Mobile phase: ethanol; Flow rate: 1 ml/min). The first eluting diastereomer was listed as Example 44 and the second eluting diastereomer as Example 45. Each of these diastereomers was subjected to final purification by reverse phase HPLC (Column: Nouryon Kromasil 100-5 C18, 21.5 x 100 mm, 5 µm; Mobile phase A : water containing 0.1% formic acid; Mobile phase B: acetonitrile; Gradient: 20% to 40% B). Using analytical HPLC (Column: Column: Chiral Technologies Chiralpak IA, 4.6 x 250 mm; Mobile phase: ethanol; Flow rate: 1.0 ml/min) Example 44 showed a retention time of 9.78 min. Example 45 had a retention time of 13.69 minutes under the same conditions.

22. The product was separated into its constituent diastereomers using supercritical fluid chromatography (Column: Chiral Technologies Chiralcel OJ-H, 20x250 mm, 5 µm; Mobile phase: 72:28 carbon dioxide/ethanol; Flow rate: 50 ml/min) . The first eluting diastereomer was specified as Example 46 and the second eluting diastereomer as Example 47. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-3R, 3.0×150 mm, 3 μm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 2.5 ml/min] Example 46 showed a retention time of 1.62 min. Example 4-7 had a retention time of 2.77 minutes under the same conditions.

23. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 20×250 mm, 5 µm; Mobile phase: 88:12 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 50 ml/min]. The first eluting diastereomer was specified as Example 48 and the second eluting diastereomer as Example 49. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-3R, 3.0×150 mm, 3 μm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 2.0 ml/min] Example 48 showed a retention time of 2.43 min. Example 49 had a retention time of 3.04 minutes under the same conditions.

24. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 20×250 mm, 5 µm; Mobile phase: 84:16 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 50 ml/min]. The first eluting diastereomer was specified as Example 50 and the second eluting diastereomer as Example 51. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-3R, 3.0×150 mm, 3 μm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 2.5 ml/min] Example 50 showed a retention time of 1.77 min. Example 51 had a retention time of 2.16 minutes under the same conditions.

25. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 20×250 mm, 5 µm; Mobile phase: 86:14 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 50 ml/min]. The first eluting diastereomer was specified as Example 52 and the second eluting diastereomer as Example 53. When performing analytical supercritical fluid chromatography (Column: Chiral Technologies Chiralcel 0J-3R, 3.0×150 mm, 3 μm; Mobile phase: 4:1 dioxide carbon/(methanol containing 0.1% diethylamine); Flow rate: 2.0 ml/min) Example 52 showed a retention time of 2.2 4 min. Example 53 had a retention time of 2.58 minutes under the same conditions.

26. The product was separated into its constituent diastereomers using HPLC (Column: Chiral Technologies Chiralpak IG, 25x250 mm, 10 µm; Mobile phase: ethanol; Flow rate: 30 ml/min). The first eluting diastereomer was specified as Example 55 and the second eluting diastereomer as Example 56. When performing analytical HPLC (Column: Chiral Technologies Chiralpak IG-3, 4.6×150 mm, 3 μm; Mobile phase: ethanol; Flow rate: 0 .5 ml/min) Example 55 showed a retention time of 9.7 9 min. Example 56 had a retention time of 12.37 minutes under the same conditions.

27. Conversion of 3-fluoro-4-iodo-2-methoxypyridine to the desired 2-(3-fluoro-2-methoxypyridin-4-yl)propanoic acid was carried out using the method described in Preparation P5. LCMS m/z 200.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 7.89 (d, J=5.3 Hz, 1H), 6.83 (dd, J=5.5 Hz, 1H), 4.09 (sq. , J=7.2 Hz, 1H), 4.02 (s, 3H), 1.52 (d, J=7.4 Hz, 3H).

28. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 20×250 mm, 5 μm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 50 ml/min]. The first eluting diastereomer was specified as Example 57 and the second eluting diastereomer as Example 58. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-3R, 3.0×150 mm, 3 μm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 2.5 ml/min] Example 57 showed a retention time of 1.7 7 min. Example 58 had a retention time of 2.92 minutes under the same conditions.

29. Conversion of 5-chloro-4-iodopyridin-2-ol to the desired 2-[5-chloro-2-(difluoromethoxy)pyridin-4-yl]propanoic acid was carried out using the method described in Preparation P5. LCMS m/z 252.1 (chlorine isotopic pattern observed) [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.21 (s, 1H), 7.50 (t, J _HF =72.8 Hz, 1H), 7.01 (s, 1H), 4, 13 (sq., J=7.2 Hz, 1H), 1.52 (d, J=7.2 Hz, 3H).

30. The product was separated into its constituent diastereomers using HPLC (Column: Chiral Technologies Chiralpak AD, 50x250 mm, 10 µm; Mobile phase: 70:30:0.1 methanol/acetonitrile/diethylamine; Flow rate: 50 ml/min ). The first eluting diastereomer was specified as Example 59 and the second eluting diastereomer as Example 60. When performing analytical HPLC (Column: Chiral Technologies Chiralpak AD-H, 4.6×150 mm, 5 μm; Mobile phase: 4:1 methanol/acetonitrile ; Flow rate: 1.0 ml/min) Example 59 showed a retention time of 3.16 min. Example 60 had a retention time of 6.23 minutes under the same conditions.

31. Final purification was accomplished using C18 reverse phase chromatography (Mobile phase A: water containing 0.1% formic acid; Mobile phase B: acetonitrile; Gradient: 0% to 50% B).

32. The product was separated into its constituent diastereomers using HPLC (Column: Chiral Technologies Chiralpak AY, 50x250 mm, 10 µm; Mobile phase: 70:30:0.1 hexane/ethanol/diethylamine; Flow rate: 60 ml/min ). The first eluting diastereomer was specified as Example 61 and the second eluting diastereomer as Example 62. When performing analytical HPLC (Column: Chiral Technologies Chiralpak AY-3, 4.6×150 mm, 3 μm; Mobile phase: 70:30:0, 1 hexane/ethanol/diethylamine; Flow rate: 1.0 ml/min) Example 61 showed a retention time of 4.41 min. Example 62 had a retention time of 5.60 minutes under the same conditions.

33. The reaction of 5-chloro-4-iodopyridin-2-ol with 1-trifluoromethyl-1,2-benziodoxol-3-(1H)-one in nitromethane at 100°C gave 5-chloro-4-iodo-2-( trifluoromethoxy)pyridine. This material was converted to the desired 2-[5-chloro-2-(trifluoromethoxy)pyridin-4-yl]propanoic acid using the method described in Preparation P5. LCMS m/z 270.0 (observed chlorine isotope pattern) [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.32 (s, 1H), 7.20 (s, 1H), 4.17 (q.v., J=7.3 Hz, 1H), 1, 54 (d, J=7.3 Hz, 3H).

34. The product was separated into its constituent diastereomers using HPLC (Column: Chiral Technologies Chiralpak AD, 50 x 250 mm, 10 µm; Mobile phase: 100:0.1 methanol/diethylamine; Flow rate: 60 ml/min). The first eluting diastereomer was specified as Example 63 and the second eluting diastereomer as Example 64. When performing analytical HPLC (Column: Chiral Technologies Chiralpak AD-H, 4.6×250 mm, 5 μm; Mobile phase: 100:0.1 methanol /diethylamine; Flow rate: 1.0 ml/min) Example 63 showed a retention time of 7.22 minutes. Example 64 had a retention time of 10.44 minutes under the same conditions.

35. Final purification was carried out using C18 reverse phase chromatography (Mobile phase A: water containing 0.1% formic acid; Mobile phase B: acetonitrile; Gradient: 0% to 40% B).

36. The product was separated into its constituent enantiomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak AD-H, 20 x 250 mm, 5 µm; Mobile phase: 64:36 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 50 ml/min]. The first eluting enantiomer was indicated as Example 65 and the second eluting enantiomer as Example 66. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralpak AD-3R, 3.0×150 mm, 3 μm; Mobile phase: 65:35 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 2.0 ml/min] Example 65 showed a retention time of 1.32 min. Example 66 had a retention time of 1.79 minutes under the same conditions.

37. The reaction used a bromine-containing heterocyclic compound (2-bromo-5-methoxypyrimidine), rather than a chlorine-containing derivative.

38. Demethylation of Example 14 was carried out using trimethylsilyl iodide in acetonitrile at reflux to give (2R)-2-(5-fluoro-2-hydroxypyridin-4-yl)-1-[{2S)-7-methyl-6 -(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one. This material can be reacted with iodo( ^2H3 )methane and potassium carbonate in N,N- _{dimethylformamide} to give Example 74.

39. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IG-H, 20 x 250 mm, 5 µm; Mobile phase: 54:46 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 45 ml/min]. The first eluting diastereomer was specified as Example 75 and the second eluting diastereomer as Example 76. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IG-3R, 3.0×150 mm, 3 μm; Mobile phase: 1:1 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 1.5 ml/min] Example 75 showed a retention time of 1.93 min. Example 76 had a retention time of 2.9 9 minutes under the same conditions.

40. The product was separated into its constituent diastereomers using HPLC (Column: Chiral Technologies Chiralpak AD, 50x250 mm, 10 µm; Mobile phase: 70/30/0.1 methanol/acetonitrile/diethylamine; Flow rate: 60 ml/min ). The first eluting diastereomer was specified as Example 77 and the second eluting diastereomer as Example 78. When performing analytical HPLC (Column: Chiral Technologies Chiralpak AD-3, 4.6×250 mm, 3 μm; Mobile phase: 70/30/0, 1 methanol/acetonitrile/diethylamine; Flow rate: 1.0 ml/min) Example 77 showed a retention time of 2.58 min. Example 78 had a retention time of 4.41 minutes under the same conditions.

41. Conversion of 5-fluoro-4-iodo-2-(trifluoromethyl)pyridine to the desired 2-[5-fluoro-2-(trifluoromethyl)pyridin-4-yl]propanoic acid was carried out using the method described in Preparation P5. LCMS m/z 238.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 8.55 (s, 1H), 7.70 (d, J=5.4 Hz, 1H), 4.14 (q.v., J=l.3 Hz , 1H), 1.61 (d, J=7.3 Hz, 3H).

42. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IG-H, 20×250 mm, 5 µm; Mobile phase: 54:46 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 45 ml/min]. The first eluting diastereomer was specified as Example 79 and the second eluting diastereomer as Example 80. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IG-3R, 3.0×150 mm, 3 μm; Mobile phase: 1:1 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 1.5 ml/min] Example 79 showed a retention time of 1.97 min. Example 80 had a retention time of 3.41 minutes under the same conditions.

43. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 20×250 mm, 5 µm; Mobile phase: 86:14 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 50 ml/min]. The first eluting diastereomer was specified as Example 81 and the second eluting diastereomer as Example 82. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-3R, 3.0×150 mm, 3 μm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 2.5 ml/min] Example 81 showed a retention time of 1.55 min. Example 82 had a retention time of 1.79 minutes under the same conditions.

44. 2,6-Dimethoxy-4-methylpyridine was converted to the desired 2-(2,6-dimethoxypyridin-4-yl)propanoic acid using the method described in Preparation P1. LCMS m/z 212.1 [M+H] ⁺ . ^1H NMR (400 MHz, chloroform-d) δ 6.26 (s, 2H), 3.90 (s, 6H), 3.63 (q, J=7.2 Hz, 1H), 1.47 (d, J=7.1 Hz, 3H).

45. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 20 x 250 mm, 5 µm; Mobile phase: 86:14 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 50 ml/min]. The first eluting diastereomer was specified as Example 83 and the second eluting diastereomer as Example 84. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralcel 0J-3R, 3.0×150 mm, 3 μm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 2.5 ml/min] Example 83 showed a retention time of 1.75 min. Example 84 had a retention time of 2.11 minutes under the same conditions.

46. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OD-H, 20 x 250 mm, 5 µm; Mobile phase: 68:32 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 50 ml/min]. The first eluting diastereomer was designated as Example 85 and the second eluting diastereomer as Example 86. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies ChiralCel OD-3R, 3.0×150 mm, 3 μm; Mobile phase: 7:3 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 2.0 ml/min] Example 85 showed a retention time of 1.70 min. Example 86 had a retention time of 2.14 minutes under the same conditions.

47. Hydrogenation of C72 over palladium hydroxide gave the desired 7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine].

48. The product was separated into its constituent enantiomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 21 x 250 mm, 5 µm; Mobile phase: 9:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 200 bar]. The first eluting enantiomer was listed as Example 87 and the second eluting enantiomer as Example 88.

49. Conditions for analytical HPLC. Column: Phenomenex Lux Cellulose-3, 4.6x100 mm, 5 µm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 200 bar.

50. Conditions for analytical HPLC. Column: Waters Atlantis dC18, 4.6x50 mm, 5 µm; Mobile phase A: 0.05% trifluoroacetic acid in water (v/v); Mobile phase B: 0.05% trifluoroacetic acid in acetonitrile (v/v); Gradient: 5.0% to 95% B, linear for 4.0 minutes, then 95% B for 1.0 minutes; Flow rate: 2 ml/min.

51. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OD-H, 21 x 250 mm, 5 µm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 200 bar]. The first eluting diastereomer was designated as Example 90 and the second eluting diastereomer as Example 91.

52. Conditions for analytical HPLC. Column: Phenomenex Lux Cellulose-1, 4.6x100 mm, 5 µm; Mobile phase: 3:2 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 200 bar.

53. Conversion of C74 to the desired 7-methyl-6-[1-methyl-5-(trifluoromethyl)-1H-1,2,4-triazol-3-yl]-3,4-dihydro-1H-spiro[1, 8-naphthyridine-2,3'-pyrrolidine] was carried out using the method described for the synthesis of P31 from C74 in Preparation of P31.

54. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IB, 21 x 250 mm, 5 µm; Mobile phase: 9:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 200 bar]. The first eluting diastereomer was listed as Example 92 and the second eluting diastereomer as Example 93.

55. Conditions for analytical HPLC. Column: Chiral Technologies Chiralpak IB, 4.6x100 mm, 5 µm; Mobile phase: 85:15 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 200 bar.

56. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Phenomenex Lux Cellulose-1, 21 x 250 mm, 5 µm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was designated as Example 94 and the second eluting diastereomer as Example 95.

57. Conditions for analytical HPLC. Column: Phenomenex Lux Cellulose-1, 4.6x100 mm, 5 µm; Mobile phase: 7:3 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 200 bar.

58. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 21×250 mm, 5 µm; Mobile phase: 92:8 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 200 bar]. The first eluting diastereomer was designated as Example 96 and the second eluting diastereomer as Example 97.

59. Conditions for analytical HPLC. Column: Phenomenex Lux Cellulose-3, 4.6x100 mm, 5 µm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar.

60. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 21 x 250 mm, 5 µm; Mobile phase: 92:8 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 200 bar]. The first eluting diastereomer was designated as Example 98 and the second eluting diastereomer as Example 99.

61. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 21 x 250 mm, 5 µm; Mobile phase: 92:8 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 200 bar]. The first eluting diastereomer was designated as Example 100 and the second eluting diastereomer as Example 101.

62. Reaction of P17 with 1,3-dichloro-5,5-dimethylimidazolidine-2,4-dione gave the desired tert-butyl-6-chloro-7-methyl-3,4-dihydro-1H-spiro[1,8- naphthyridine-2,3'-pyrrolidine]-1'-carboxylate.

63. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 21 x 250 mm, 5 µm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was designated as Example 102 and the second eluting diastereomer as Example 103.

64. Conditions for analytical HPLC. Column: Chiral Technologies Chiralcel OJ-H, 4.6×100 mm, 5 µm; Mobile phase: 7:3 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar.

65. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Phenomenex Lux Cellulose-1, 21 x 250 mm, 5 µm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was designated as Example 104 and the second eluting diastereomer as Example 105.

66. Conditions for analytical HPLC. Column: Phenomenex Lux Cellulose-1, 4.6x100 mm, 5 µm; Mobile phase: 65:35 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 200 bar.

67. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak AS-H, 21 x 250 mm, 5 µm; Mobile phase: 9:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was designated as Example 107 and the second eluting diastereomer as Example 108.

68. Conditions for analytical HPLC. Column: Chiral Technologies Chiralpak AS-H, 4.6×100 mm, 5 µm; Mobile phase: 85:15 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar.

69. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IB, 21 x 250 mm, 5 µm; Mobile phase: 85:15 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was listed as Example 109 and the second eluting diastereomer as Example 110.

70. Conditions for analytical HPLC. Column: Chiral Technologies Chiralpak IB, 4.6x100 mm, 5 µm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar.

71. Conversion of P23 to the desired compound (2S)-7-methyl-6-([1,2,4]triazolo[1,5-a]pyridin-2-yl)-3,4-dihydro-1H-spiro[ 1,8-naphthyridine-2,3'-pyrrolidine], dihydrochloride salt, was carried out using the method described in Alternative Preparation P26; in this case, 2-bromo[1,2,4]triazolo[1,5-a]pyridine was used instead of 5-bromo-2-methyl-2H-tetrazole.

72. Conversion of P21 to the desired compound 6-(5-methoxy-1-methyl-1H-1,2,4-triazol-3-yl)-7-methyl-3,4-dihydro-1H-spiro[1,8 -naphthyridine-2,3'-pyrrolidine], dihydrochloride salt, was carried out using the method described in Alternative Preparation P26; in this case, 3-bromo-5-methoxy-1-methyl-1H-1,2,4-triazole was used instead of 5-bromo-2-methyl-2H-tetrazole.

73. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IB, 21 x 250 mm, 5 µm; Mobile phase: 85:15 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 200 bar]. The first eluting diastereomer was designated as Example 112 and the second eluting diastereomer as Example 113.

74. Conditions for analytical HPLC. Column: Chiral Technologies Chiralpak IB, 4.6x100 mm, 5 µm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar.

75. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IB, 21 x 250 mm, 5 µm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 200 bar]. The first eluting diastereomer was designated as Example 114 and the second eluting diastereomer as Example 115.

76. Conditions for analytical HPLC. Column: Chiral Technologies Chiralpak IB, 4.6x100 mm, 5 µm; Mobile phase: 3:2 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar.

77. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IB, 21 x 250 mm, 5 µm; Mobile phase: 85:15 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 200 bar]. The first eluting diastereomer was Example 13 and the second eluting diastereomer was reported as Example 116. Example 13 showed a retention time of 3.26 minutes. Example 116 had a retention time of 3.52 minutes under the same conditions (see note 74).

78. Conversion of P23 to the desired compound (2S)-7-methyl-6-(2-methyl-2H-1,2,3-triazol-4-yl)-3,4-dihydro-1H-spiro[1,8 -naphthyridine-2,3'-pyrrolidine], dihydrochloride salt, was carried out using the method described in Alternative Preparation P26; in this case, 4-bromo-2-methyl-2H-1,2,3-triazole was used instead of 5-bromo-2-methyl-2H-tetrazole.

79. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IA, 21 x 250 mm, 5 µm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 150 bar]. The first eluting diastereomer was designated as Example 123 and the second eluting diastereomer as Example 124.

80. Conditions for analytical HPLC. Column: Chiral Technologies Chiralpak IA, 4.6x100 mm, 5 µm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 200 bar.

81. Methyl (2-methoxypyridin-4-yl) acetate was converted to the desired 2-(2-methoxypyridin-4-yl)propanoic acid using the method described in Preparation P1. LCMS m/z 182.1 [M+H] ⁺ . ¹ H NMR (400 MHz, DMSO-d ₆ ) δ 12.53 (b.s, 1H), 8.09 (d, J=5.3 Hz, 1H), 6.90 (d, J=5, 3 Hz, 1H), 6.71 (s, 1H), 3.83 (s, 3H), 3.69 (sq., J=7.l Hz, 1H), 1.34 (d, J=7 ,l Hz, 3H).

82. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 21 x 250 mm, 5 µm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was designated as Example 125 and the second eluting diastereomer as Example 126.

83. Conditions for analytical HPLC. Column: Chiral Technologies Chiralcel OJ-H, 4.6×100 mm, 5 µm; Mobile phase: 3:2 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar.

84. 2,4-Dichloro-6-methoxypyrimidine was converted to dimethyl (2-chloro-6-methoxypyrimidin-4-yl)(methyl)propanedioate in accordance with the method described in step 1 of Preparation P4. This material was then used to synthesize the desired lithium 2-[2-(difluoromethyl)-6-methoxypyrimidin-4-yl]propanoate using the method described in Preparation P9. LCMS m/z 233.1 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 6.91 (s, 1H), 6.54 (t, J _HF =54.7 Hz, 1H), 4.01 (s, 3H), 3, 71 (sq., J=7.2 Hz, 1H), 1.48 (d, J=l.2 Hz, 3H).

85. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IA, 21 x 250 mm, 5 µm; Mobile phase: 7:3 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was designated as Example 127 and the second eluting diastereomer as Example 128.

86. Conditions for analytical HPLC. Column: Chiral Technologies Chiralpak IA, 4.6x100 mm, 5 µm; Mobile phase: 3:2 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar.

87. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IA, 21 x 250 mm, 5 µm; Mobile phase: 3:2 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was listed as Example 129 and the second eluting diastereomer as Example 130.

88. Using the method described in DW C. MacMillan et al., J. Amer. Chem. Soc. 2016, 138, 8084-8087, p23 can be reacted with 4-bromotetrahydro-2H-pyran, in the presence of a photochemical catalyst [Ir{dF(CF ₃ )ppy} ₂ (dtbpy)]PF ₆ , to obtain tert-butyl-( 2S)-7-methyl-6-(oxan-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate. Deprotection using hydrogen chloride gave the desired compound (2S)-7-methyl-6-(oxan-4-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine] dihydrochloride salt.

89. Conditions for analytical HPLC. Column: Chiral Technologies Chiralpak IA, 4.6x100 mm, 5 µm; Mobile phase: 65:35 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar.

90. Conversion of 4-chloro-5-fluoro-2-methoxypyrimidine to the desired 2-(5-fluoro-2-methoxypyrimidin-4-yl)propanoic acid was carried out using the method described in Preparation P4. The resulting acid contained 4-ethyl-5-fluoro-2-methoxypyrimidine as an impurity. LCMS m/z 201.1 [M+H] ⁺ . ^1H NMR (400 MHz, DMSO- _d6 ), product peaks only: δ 8.32 (s, 1H), 3.85 (s, 3H), 3.56 (sq., J=7.3 Hz, 1H), 1.34 (d, J=7.3 Hz, 3H).

91. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 21 x 250 mm, 5 µm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 12 0 bar]. The first eluting diastereomer was designated as Example 132 and the second eluting diastereomer as Example 133.

92. Conditions for analytical HPLC. Column: Chiral Technologies Chiralcel OJ-H, 4.6×100 mm, 5 µm; Mobile phase: 3:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Back pressure: 120 bar.

93. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak AS-H, 21 x 250 mm, 5 µm; Mobile phase: 85:15 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was designated as Example 134 and the second eluting diastereomer as Example 135.

94. Conditions for analytical HPLC. Column: Chiral Technologies Chiralpak AS-H, 4.6×100 mm, 5 µm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar.

95. Conversion of 2-methoxy-4,5-dimethylpyridine to the desired 2-(2-methoxy-5-methylpyridin-4-yl)propanoic acid was carried out using the method described in Preparation P1. LCMS m/z 196.1 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 7.89 (b.s, 1H), 6.69 (s, 1H), 3.90 (q.v., J=7.1 Hz, 1H), 3.86 (s, 3H), 2.26 (brs, 3H), 1.44 (d, J=1.2 Hz, 3H).

96. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak IA, 5 µm; Mobile phase: 1:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was designated as Example 136 and the second eluting diastereomer as Example 137.

97. Conditions for analytical HPLC. Column: Chiral Technologies Chiralpak IA, 4.6x100 mm, 5 µm; Mobile phase: 1:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 1.5 ml/min; Back pressure: 120 bar.

98. Reaction of p27 with 1-(difluoromethyl)-4-iodo-2-methyl-1L-imidazole using the method described for the conversion of p27 to c84 in Example 18 gave the desired tert-butyl-(2S)-6-[1 -(difluoromethyl)-2-methyl-1H-imidazol-4-yl]-7-methyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidine]-1'-carboxylate .

99. The desired 1-(difluoromethyl)-4-iodo-2-methyl-1H-imidazole was prepared from 4-iodo-2-methyl-1H-imidazole using the method described for the synthesis of C5 in Preparation P5.

100. A suitable bromo-substituted heteroaromatic compound was used in palladium catalyzed coupling.

101. A suitable chlorine-substituted heteroaromatic compound was used in a palladium-catalyzed coupling.

102. The reaction of 3,5-dibromo-1H-1,2,4-triazole with 4-bromobut-1-ene in the presence of potassium carbonate gave 3,5-dibromo-1-(but-3-en-1-yl) -1H-1,2,4-triazole; this substance was cyclized to 2-bromo-7-methylidene-6,7-dihydro-5H-pyrrolo[1,2-b][1,2,4]triazole using 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (SPhos), chloro(2-dicyclohexylphosphino-2',6'-dimethoxy-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(II) (SPhos Pd G2 ) and triethylamine at elevated temperatures. After ozonolysis to the ketone, reaction was carried out with (diethylamino)sulfur trifluoride to obtain the desired 2-bromo-7,7-difluoro-6,7-dihydro-5H-pyrrolo[1,2-b][1,2,4]triazole.

103. Conversion of c29 to the desired 2-fluoro-2-(5-fluoro-2-methoxypyridin-4-yl)propanoic acid was accomplished using the method described for steps 5 and 6 of Preparation P10. LCMS m/z 218.1 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.01 (d, J=2.6 Hz, 1H), 6.92 (d, J=5.0 Hz, 1H), 3.90 (s , 3Н), 1.91 (br.d, J _HF =23.1 Hz, 3Н).

104. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralpak AS-H, 21 x 250 mm, 5 µm; Mobile phase: 9:1 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 75 ml/min; Back pressure: 120 bar]. The first eluting diastereomer was listed as Example 14 8 and the second eluting diastereomer as Example 149.

105. 3-Bromobenzohydrazide was acylated with acetyl chloride in the presence of triethylamine and then cyclized with p-toluenesulfonyl chloride and triethylamine to give the desired 2-bromo-6-(5-methyl-1,3,4-oxadiazol-2-yl)pyridine.

106. Iodination of 5-methyl-1H-1,2,4-triazole using N-iodosuccinimide in N,N-dimethylformamide at elevated temperature gave 3-iodo-5-methyl-1H-1,2,4-triazole; this material was converted to the desired 1-(difluoromethyl)-3-iodo-5-methyl-1H-1,2,4-triazole using the method described for the synthesis of C31 from C30 in Preparation P13.

107. The reaction of 3,5-dibromo-1H-1,2,4-triazole with cyclopropylboronic acid in the presence of copper(II) acetate, 2,2'-bipyridine and sodium carbonate in 1,2-dichloroethane at 70°C gave 3 ,5-dibromo-1-cyclopropyl-1H-1,2,4-triazole. Lithium-halogen exchange was then carried out using n-butyllithium (1.1 equivalents) at -78°C and the resulting anion was reacted with N,N-dimethylformamide to give 3-bromo-1-cyclopropyl-1H-1,2,4 -triazole-5-carbaldehyde. This material was reacted with [bis(2-methoxyethyl)amino]sulfur trifluoride in dichloromethane to give the desired 3-bromo-1-cyclopropyl-5-(difluoromethyl)-1H-1,2,4-triazole.

108. The product was separated into its constituent diastereomers using supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-H, 20×250 mm, 5 µm; Mobile phase: 86:14 carbon dioxide/(methanol containing 0.2% ammonium hydroxide); Flow rate: 50 ml/min]. The first eluting diastereomer was specified as Example 190 and the second eluting diastereomer as Example 191. When performing analytical supercritical fluid chromatography [Column: Chiral Technologies Chiralcel OJ-3R, 3.0×150 mm, 3 μm; Mobile phase: 4:1 carbon dioxide/(methanol containing 0.1% diethylamine); Flow rate: 2.0 ml/min] Example 190 showed a retention time of 2.7 0 min. Example 191 had a retention time of 3.33 minutes under the same conditions.

109. The product was separated into its constituent diastereomers using HPLC (Column: Chiral Technologies Chiralcel OD, 25 x 250 mm, 10 µm; Mobile phase: 4:1 hexane/ethanol; Flow rate: 25 ml/min). The first eluting diastereomer was specified as Example 192 and the second eluting diastereomer as Example 193. When performing analytical HPLC (Column: Chiral Technologies Chiralcel OD-H, 4.6×150 mm, 5 μm; Mobile phase: 85:15 hexane/ethanol ; Flow rate: 1.0 ml/min) Example 192 showed a retention time of 6.2 0 min. Example 193 had a retention time of 7.06 minutes under the same conditions.

110. Final purification was carried out using C18 reverse phase chromatography (Mobile phase A: water containing 0.1% formic acid; Mobile phase B: acetonitrile; Gradient: 0% to 45% B).

111. Using the method described for the synthesis of P13 from C30 in Preparation of P13, methyl 2-(2-hydroxypyridin-4-yl)propanoate was converted to the desired 2-[2-(difluoromethoxy)pyridin-4-yl]propanoic acid. LCMS m/z 218.0 [M+H] ⁺ . ¹ H NMR (400 MHz, methanol-d ₄ ) δ 8.14 (b, J = 5.3 Hz, 1H), 7.53 (t, J _HF = 73.1 Hz, 1H), 7, 16 (dd, J=5.3, 1.5 Hz, 1H), 6.93-6.91 (m, 1H), 3.80 (sq., J=7.2 Hz, 1H), 1, 48 (d, J=7.2 Hz, 3H).

112. The product was separated into its constituent diastereomers using HPLC (Column: Chiral Technologies Chiralpak IG, 50 x 250 mm, 10 µm; Mobile phase: 4:1 ethanol/acetonitrile; Flow rate: 30 ml/min). The first eluting diastereomer was specified as Example 194 and the second eluting diastereomer as Example 195. When performing analytical HPLC (Column: Chiral Technologies Chiralpak IG, 4.6×150 mm, 5 μm; Mobile phase: 4:1 ethanol/acetonitrile; Speed flow: 0.5 ml/min), Example 194 showed a retention time of 6.48 min. Example 195 had a retention time of 8.08 minutes under the same conditions.

Example AA. In vitro binding affinity assay using hMC4R

The binding affinity of the test compounds to the α-melanocyte stimulating hormone receptor (hMC4R) was assessed using a radioligand competition binding assay. Recombinant Chinese hamster ovary (CHO) cells stably expressing hMC4R (PerkinElmer #ES-191-C) were used for competitive binding. hMC4R membranes were grown in Dulbecco's modified essential medium and Ham's F-12 medium (DMEM/F12), with 10% heat-inactivated fetal bovine serum (FBS), 0.4 mg/ml geneticin, and 2 mM L-glutamine. Cell membranes were collected and frozen until analysis.

Compounds were solubilized in 100% dimethyl sulfoxide (DMSO) to a concentration of 30 mM. A 10-point intermediate dilution series using half-log dilutions was prepared in 100% DMSO with a maximum concentration of 0.03 mM. Serially diluted compounds were applied at 1 μl/well to Costar 3363 96-well plates. The final range of compounds in the assay was from 300 nM to 0.01 nM with a final DMSO concentration of 1%. Control wells containing 1 μl of 2 mM (2 μM final concentration) alpha-melanocyte stimulating hormone (cx-MSH-Tocris #2584) were added to nonspecific binding wells and 1 μl of 100% DMSO for all control binding wells. After this, 80 μl of assay buffer [25 mM HE PES, 5 mM MgCl ₂ , 2.5 mM CaCl ₂ , 150 mM NaCl, EDTA-free protease inhibitor complete tablet (Thermo Scientific #11873580001) and 0.25% BSA] was added. 10 µl [ ¹²⁵ I]-(Nle4, D-Phe7)-α-MSH (PerkinElmer #NEX3520) was added to all wells at 10 times the final concentration of 0.5 nM. The radioligand concentration used was below the equilibrium dissociation constant ( _Kd ) of 2.59 nM. The exact concentration of radioligand used for each experiment was determined by liquid scintillation counting and adjusted as necessary.

Frozen hMC4R cell membranes were thawed and homogenized in a Dounce homogenizer. Homogenates were resuspended in assay buffer to a concentration of 2 μg per well. The competitive binding reaction was initiated by adding 10 μl of MC4R membrane solution to assay-ready plates containing the test compound and [ ¹²⁵ I]-(Nle4, D-Phe7)-α-MSH. The plates were incubated for 2 hours at room temperature. Samples for analysis were then quickly filtered through Unifilter-96 GF/B PEI-coated filter plates using a filter plate sample collector (PerkinElmer) and washed with ice-cold wash buffer [25 mM (4-(2-hydroxyethyl)-1- piperazine ethanesulfonic acid (HEPES), 1 mM MgCl ₂ , 2.5 mM CaCl ₂ and 500 mM NaCl] Filter plates were dried overnight at room temperature and the plates were then sealed at the bottom before adding 50 µL/well of Ultima Gold XR scintillation fluid ( PerkinElmer 6013111) The plates were then sealed at the top, incubated for 60 minutes at room temperature, and the amount of radioactivity present was determined by liquid scintillation counting on a Microbeta Trilux (PerkinElmer #2450-0060).

Raw data (expressed as counts per minute) were analyzed using ActivityBase (IDBS data management software). The percentage effect at each compound concentration was calculated using ActivityBase based on the values for wells with no inhibition (total binding controls) and wells with complete inhibition (nonspecific binding controls) on each assay plate. The concentration required for 50% inhibition (IC ₅₀ ) was determined from these data using a 4-parameter logistic model. The equilibrium dissociation constant for the ligand-receptor interaction inhibitor (K _i ) was then calculated from the IC ₅₀ values using the Cheng-Prusoff equation: K _i =IC ₅₀ /(1+([L]/K _d )), where [L] represents is the concentration of the radioligand used in the experiment, and K _d is the affinity of the radioligand (determined in separate saturation experiments).

Example BB. Analysis of the functional activity of the MC4R antagonist in vitro

The in vitro functional antagonistic activity of the test compounds was determined by monitoring intracellular cyclic adenosine monophosphate (cAMP) levels in Chinese hamster ovary (CHO-) cells stably expressing the human melanocortin-4 receptor (MC4R). Upon activation by an agonist, human MC4R binds to the G protein complex, causing the Gα subunit to exchange bound GDP for GTP, followed by dissociation of the Gα-GTP complex. The activated Gα subunit can bind to downstream effectors to regulate levels of second messengers or cAMP within the cell. Thus, determination of intracellular cAMP levels provides the opportunity to determine pharmacological characteristics. Intracellular cAMP levels are quantified using a homogeneous assay using the homogeneous time-resolved fluorescence (HTRF) method from CisBio. This method is a competitive immunoassay between native cAMP produced by cells and cAMP labeled with the acceptor dye d2. These two molecules then compete for binding to a cryptate-labeled monoclonal anti-cAMP antibody. The specific signal is inversely proportional to the concentration of cAMP in the cells.

Test compounds were solubilized to a concentration of 30 mM in 100% dimethyl sulfoxide (DMSO) and stored. An 11-point dilution series using 1 in 3 162-fold serial dilutions was performed in 100% DMSO with a maximum concentration of 800 μM. Serially diluted compound was added to a 384-well plate (Greiner, catalog no. 781280) at 40 nL/well with duplicate spots for each concentration and then diluted 1 in 1000 using 40 μL assay buffer containing HBSS, 20 mM HEPES (Invitrogen), 0.1% BSA and 250 µM IBMX (Sigma Aldrich), to create a 2x final assay concentration (FAC) intermediate plate. The final compound concentration range in the assay was 400 nM to 4 pM with a final DMSO concentration of 0.1%.

CHO cells obtained in our own laboratory, stably expressing the human Gs-coupled receptor MC4R, were seeded into 384-well assay plates (Corning, catalog no. 3570) in 50 μl/well of Ham's F-12 medium containing 10% heat-inactivated FBS, 1x penicillin/streptomycin, 1 mM Glutamax (Invitrogen), at a density of 2500 cells per well and incubated at 37°C (95% O ₂ : 5% CO ₂ ) overnight using micro-clime lids (Labcyte, catalog no. LLS-0310). On the day of analysis, the medium was removed from the assay plate by gently tapping and blotting the plate with a paper towel and replaced with 5 μl of 2x antagonist compound in assay buffer (HBSS, 20 mM HEPES, 0.1% BSA, 250 μM IBMX) and 0. 1% DMSO. Cells were incubated with the compound for 30 minutes at 37°C (95% 02:5% CO ₂ ) before stimulation by adding 5 μl of EC80 agonist (200 nM α-melanocyte-stimulating hormone, aMSH, Bachem) and another 30-minute incubation at 37°C (95% O ₂ : 5% CO ₂ ). Intracellular cAMP levels were quantified according to the Cisbio protocol (5 μl D2 followed by 5 μl cryptate, incubation for 1–2 h at room temperature). Samples were measured on an Envision plate reader (PerkinElmer Life and Analytical Sciences; excitation at 320 nm; emission at 665 nm/620 nm).

Data were analyzed using the ratio of fluorescence intensity at 620 and 665 nm for each well, extrapolated from the cAMP standard curve to express the data as nM cAMP for each well. Data, expressed as nM cAMP, were then normalized to control wells using Activity Base (IDBS). Zero percent effect (ZPE) was defined as nM cAMP generated upon stimulation with EC80 agonist (200 nM aMSH). In the absence of an antagonist control compound, 100% effect (HPE) was defined as nM cAMP generated from assay buffer/vehicle only. The concentration and % effect values for each compound were plotted using Activity Base using a four-parameter logistic dose-response equation and the concentration required for 50% inhibition (IC ₅₀ ) was determined. Then the values of the equilibrium dissociation constant (Kb) were calculated using the Leff-Dougall equation: K _b = [IC ₅₀ ]/((2+([A]/[EC ₅₀ ]) ⁿ ) ^1/n -1), where A = concentration agonist of interest used in the experiment (200 nM), and n = slope.

Table 2 presents the biological activities (K _i values, see Example AA; and K _b values, see Example BB) and compound names for Examples 1-201.

This application contains references to various publications. The entire disclosure of these publications is incorporated herein by reference for all purposes.

It will be apparent to those skilled in the art that various modifications and changes may be made to the present invention without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the description and practice of the invention disclosed herein. It is intended that the description and examples be considered as illustrative only and that the true scope and spirit of the invention are set forth in the following claims.

Claims (50)

1. Compound of formula I: or a pharmaceutically acceptable salt thereof, where: R ¹ is H, halogen, 4-7 membered heterocycloalkyl, phenyl, or R ^1a wherein the 4-7 membered heterocycloalkyl is optionally substituted with 1, 2, 3 or 4 independently selected C _1-4 alkyl groups, and wherein phenyl is optionally substituted 1 or 2 independently selected R ^B1 ; R ^1a is a 5- or 6-membered heteroaryl, optionally substituted with 1 or 2 independently selected ^RAs , where each ^RA is halogen, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _{1 -4} haloalkoxy, C _3-4 cycloalkyl, -N(C _1-4 alkyl) ₂ or R ^A1 , where two adjacent R ^A together with the two ring-forming 5- or 6-membered heteroaryl atoms to which they are attached form a fused 5- or 6-membered heteroaryl or fused 5- or 6-membered heterocycloalkyl, each of which is optionally substituted with 1 or 2 substituents, each independently selected from halogen or C _1-4 alkyl; R ^A1 represents a 5- or 6-membered heterocycloalkyl, which is optionally substituted with C _1-4 alkyl; R ^B1 is a 5- or 6-membered heteroaryl which is optionally substituted with C _1-4 alkyl; X ¹ represents C(R ^X ) ₂ where each R ^X independently represents H or C _1-4 alkyl; each of R ² and R ³ independently represents H, halogen or C _1-4 alkyl; each of Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ is independently CR ⁴ or N, provided that no more than 3 of Y ¹ , Y ² , Y ³ , Y ⁴ and Y ⁵ are N ; And each R ⁴ independently represents H, halogen, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy or C _1-4 haloalkoxy; where each heteroatom is independently selected from N, O and S. 2. A compound or pharmaceutically acceptable salt according to claim 1, wherein the compound is a compound of formula Ia: or a pharmaceutically acceptable salt thereof. 3. A compound or pharmaceutically acceptable salt according to claim 1 or 2, wherein the compound is a compound of formula II: or a pharmaceutically acceptable salt thereof. 4. A compound or pharmaceutically acceptable salt according to any one of paragraphs. 1-3, where the compound is a compound of formula III: or a pharmaceutically acceptable salt thereof. 5. A compound or pharmaceutically acceptable salt according to any one of paragraphs. 1-4, where: R ¹ is R ^1a ; And R ^1a is a 6-membered heteroaryl, optionally substituted with 1 or 2 independently selected R ^A , where each R ^A is halogen, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl. 6. A compound or pharmaceutically acceptable salt according to claim 5, wherein R ^1a is pyrimidinyl, optionally substituted with 1 or 2 independently selected R ^A , wherein each R ^A is halogen, C _1-4 alkyl, C _1-4 haloalkyl, C _1-4 alkoxy, C _1-4 haloalkoxy or C _3-4 cycloalkyl. 7. A compound or pharmaceutically acceptable salt according to claim 6, wherein R ^1a is pyrimidin-2-yl. 8. A compound or pharmaceutically acceptable salt according to any one of paragraphs. 1-3 and 5-7, where X ¹ represents CH ₂ . 9. A compound or pharmaceutically acceptable salt according to any one of paragraphs. 1-8, where each of R ² and R ³ independently represents H or C _1-4 alkyl. 10. A compound or pharmaceutically acceptable salt according to any one of paragraphs. 1-9, where R ² represents methyl and R ³ represents H. 11. A compound or pharmaceutically acceptable salt according to any one of paragraphs. 1-10, where Y ³ represents N, and each of Y ¹ , Y ² , Y ⁴ and Y ⁵ independently represents CR ⁴ . 12. A compound or pharmaceutically acceptable salt according to any one of paragraphs. 1-11, where each R ⁴ independently represents H, halogen or C _1-2 alkoxy. 13. The connection according to claim 1, selected from: (2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1; 2-(6-methoxy-2-methylpyrimidin-4-yl)-1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1; 2-[6-(difluoromethoxy)pyridin-3-yl]-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8- naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-2; 1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl] -2-[4-(trifluoromethyl)phenyl]propan-1-one, DIAST-1; 1-(4,7-dimethyl-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl)-2-(4-fluorophenyl)ethane-1- she, DIAST-1; (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(2-methyl-2H-tetrazol-5-yl)-3,4 -dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one; (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one; (2R)-2-(5-chloro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl)-3,4-dihydro-1H-spiro [1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one; (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[7-methyl-6-(1-methyl-1H-pyrazol-4-yl)-3,4-dihydro-1H -spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one, DIAST-1; And (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-{(2S)-7-methyl-6-[(4,6- ² H ₂ )pyrimidin-2-yl]- 3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl}propan-1-one, or a pharmaceutically acceptable salt thereof. 14. The compound according to claim 1, which is (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2-yl )-3,4-dihydro-1H-spiro[1,8-naphthyridine-2,3'-pyrrolidin]-1'-yl]propan-1-one or a pharmaceutically acceptable salt thereof. 15. The compound according to claim 1, which is the crystalline form of (2R)-2-(5-fluoro-2-methoxypyridin-4-yl)-1-[(2S)-7-methyl-6-(pyrimidin-2 -yl)-3,4-dihydro-1H-spiro[1,8-naphthyridin-2,3'-pyrrolidin]-1'-yl]propan-1-one. 16. A pharmaceutical composition containing a therapeutically effective amount of a compound or pharmaceutically acceptable salt according to any one of paragraphs. 1-15 and a pharmaceutically acceptable carrier, wherein the compound has MC4R antagonistic activity. 17. A method of treating an MC4R-related condition, disease or disorder in a human, wherein the method comprises administering to a human in need thereof a compound or a pharmaceutically acceptable salt according to any one of claims. 1-15 in a therapeutically effective amount. 18. A method of treating an MC4R-related condition, disease or disorder in a human, wherein the method comprises administering to a human in need thereof a compound or a pharmaceutically acceptable salt according to any one of claims. 1-15 in a therapeutically effective amount, wherein the condition, disease or disorder is selected from cachexia [including, for example, cachexia associated with a chronic disease such as cachexia associated with cancer, cachexia associated with acquired immunodeficiency syndrome (AIDS), cachexia, associated with heart failure, eg cachexia associated with congestive heart failure (CHF), cachexia associated with chronic kidney disease (CKD); cachexia associated with the treatment of a chronic disease, such as cachexia associated with the treatment of cancer or cachexia associated with the treatment of heart failure (eg, CIS)]; anorexia or anorexia nervosa (eg, anorexia in the elderly, anorexia associated with chemotherapy and/or radiation therapy); nausea; vomiting; weight loss (eg, unintentional weight loss); developmental delays; sarcopenia; muscle atrophy; muscle weakness; weakness; osteoporosis; bone diseases (eg, bone loss); pain; neuropathic pain; anxiety (such as post-traumatic stress disorder, or PTSD); depression; hypertension; eating disorders; obesity (eg, sarcopenia due to chronic obesity); sexual dysfunction; and an inflammatory disease (eg, an inflammatory disease associated with anorexia, or cachexia, or sarcopenia, or muscle wasting). 19. Use of a compound or pharmaceutically acceptable salt according to any one of paragraphs. 1-15 in a therapeutically effective amount in the treatment of an MC4R-related condition, disease or disorder selected from cachexia [including, for example, cachexia associated with a chronic disease, such as cachexia associated with cancer, cachexia associated with acquired immunodeficiency syndrome (AIDS ), cachexia associated with heart failure, such as cachexia associated with congestive heart failure (CHF), cachexia associated with chronic kidney disease (CKD); cachexia associated with the treatment of a chronic disease, such as cachexia associated with the treatment of cancer or cachexia associated with the treatment of heart failure (eg, CHF)]; anorexia or anorexia nervosa (eg, anorexia in the elderly, anorexia associated with chemotherapy and/or radiation therapy); nausea; vomiting; weight loss (eg, unintentional weight loss); developmental delays; sarcopenia; muscle atrophy; muscle weakness; weakness; osteoporosis; bone diseases (eg, bone loss); pain; neuropathic pain; anxiety (such as post-traumatic stress disorder, or PTSD); depression; hypertension; eating disorders; obesity (eg, sarcopenia due to chronic obesity); sexual dysfunction; and an inflammatory disease (eg, an inflammatory disease associated with anorexia, or cachexia, or sarcopenia, or muscle wasting). 20. A method of antagonizing the melanocortin-4 receptor (MC4R), comprising contacting the MC4R with a compound or pharmaceutically acceptable salt according to any one of claims. 1-15.