WO2013062680A1 - Novel compounds and compositions thereof for treating nervous system disorders - Google Patents

Abstract

The present invention relates to a novel compound, methods of synthesizing the compound, compositions containing the compound, and methods for using the compound or composition to treat and/or prevent diseases and/or conditions of the central and peripheral nervous system.

Description

SPECIFICATION

NOVEL COMPOUNDS AND COMPOSITIONS THEREOF FOR TREATING

NERVOUS SYSTEM DISORDERS

CROSS-REFERENCE TO RELATED APPLICATIONS

[001] This application claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application Number 61/551,380, filed October 25, 2011 and U.S. Provisional Patent Application No. 61/551,381, filed October 25, 2011. The contents of each of the above patent applications are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

[002] The instant disclosure relates to a novel compound, methods synthesizing the compound, compositions containing the compound, and methods for using the compound to treat and/or prevent diseases and/or conditions of the central and peripheral nervous system.

BACKGROUND OF THE INVENTION

[003] A need exists for new drug therapies having greater receptor selectivity for the treatment of subjects suffering from or susceptible to central and peripheral nervous system diseases, disorders and/or conditions. Included are diseases, disorders and conditions associated with metabotropic glutamate receptors (mGluRs), specifically mGluR2/3.

Specific central and peripheral nervous system diseases, disorders and/or conditions linked to mGluR2/3 include depression, treatment resistant depression, anxiety, Alzheimer's disease, cognition, addiction, and Parkinson's disease. Other disorders and conditions associated with metabotropic glutamate receptors (mGluRs) are cancers directly or indirectly linked to mGluR2/3, including but not limited to colon cancer and glioblastoma.

[004] In particular, a need still exists for new drugs having one or more improved properties either alone or when combined with other agents (such as bioavailability, safety, efficacy, and/or physical properties) relative to those therapies currently available. SUMMARY OF THE INVENTION

[005] The present invention is directed to Compound 1 having the following structure and the use of this compound in a pharmaceutical formulation to treat and/or prevent diseases and/or conditions of the c

[006] The chemical name for Compound 1 is (lR,2R,3R,5R,6R)-6-((((adamantane-l- carbonyl)oxy)methoxy)carbonyl)-2-amino-3-((3,4-dichlorobenzyl)oxy)-6- fluorobicyclo[3.1.0]hexane-2-carboxylic acid.

[007] Provided herein is the disclosure of a compound and various compositions comprising the compound or a pharmaceutically acceptable salt, prodrug or other derivative thereof, for the prevention and/or treatment of diseases, disorders, conditions and injuries of the central and peripheral nervous systems. In some embodiments, the compound stimulates or increases neurogenesis.

[008] In various embodiments, the methods described are for treating neurodegenerative disorders, neurological trauma including brain or central nervous system trauma and/or recovery there from, psychosis, addiction, pain, learning and memory disorders and ischemia of the central and/or peripheral nervous systems and affective disorders, including depression and anxiety.

[009] In other embodiments, the methods described are useful for improving cognitive disorders associated with multiple sclerosis, dementia, Parkinson's disease and/or stroke.

[010] In yet other embodiments, the methods described are useful for treating cancer or tumors associated with mGluR2/3. In some specific embodiments, the cancer associated with mGluR2/3 is melanoma, colon cancer or glioblastoma.

[011] In various embodiments described herein, Compound 1 is administered with at least one other active agent.

[012] Also provided herein are pharmaceutical compositions comprising a prodrug of (lR,2R,3R,5R,6R)-2-amino-3-((3,4-dichlorobenzyl)oxy)-6-fluorobicyclo[3.1.0]hexane-2,6- dicarboxylic acid (Compound 2) with an oral bioavailability of at least about 35% when administered to a subject. In some embodiments, the oral bioavailability of the prodrug is between about 35% and about 50%. In various embodiments, the pharmaceutical composition further comprises one or more pharmaceutically acceptable carriers, diluents, or

excipients. In some specific embodiments, the prodrug is

(Compound 1), or a pharmaceutically acceptable salt or hydrate thereof.

[013] Also provided herein are methods for treating a disease, disorder or condition of the central and/or peripheral nervous system comprising administering a pharmaceutical composition comprising a prodrug of (lR,2R,3R,5R,6R)-2-amino-3-((3,4- dichlorobenzyl)oxy)-6-fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (Compound 2) with an oral bioavailabilty between about 30% and about 50% when administered to a subject. In

some specific embodiments, the prodrug is

(Compound 1), or a pharmaceutically acceptable salt or hydrate thereof.

[014] In various embodiments, the disease, disorder or condition is a mGluR 2/3-dependent or mGluR 2/3-mediated disease or condition. In some embodiments, the disease, disorder or condition is selected from the group consisting of Alzheimer's disease, schizophrenia, Parkinson's disease, anxiety, depression, treatment resistant depression, obsessive compulsive disorders, psychosis, addiction, epilepsy, insomnia, brain or central nervous system trauma and/or recover therefrom, ischemia of the central and/or peripheral nervous systems, pain, learning and memory disorders and cognitive and memory deficiencies due to disease or aging.

[015] In still other embodiments, the disease, disorder or condition is a nervous system disorder related to cellular degeneration, a psychiatric condition, cognitive impairment, cellular trauma or injury, or another neurologically related condition. In some embodiments the disease, disorder or condition is a cellular degeneration disease selected from the group consisting of a neurodegenerative disorder, a neural stem cell disorder, a neural progenitor cell disorder, an ischemic disorder or a combination thereof. In specific embodiments, the neurodegenerative disorder is a degenerative disease of the retina, lissencephaly syndrome, or cerebral palsy. In other specific embodiments, the psychiatric condition is a neuropsychiatric disorder.

BRIEF DESCRIPTION OF THE DRAWINGS

[016] Figure 1 is a dose-response curve showing the effect of Compound 1

( 1 R,2R,3R,5R,6R)-6-((((adamantane- 1 -carbonyl)oxy)methoxy)carbonyl)-2-amino-3-((3 ,4- dichlorobenzyl)oxy)-6-fluorobicyclo[3.1.0]hexane-2-carboxylic acid, on neuronal differentiation of cultured human neural stem cells (hNSCs). This compound was tested in a concentration response curve ranging from 0.01 μΜ to 31.6 μΜ. Data is presented as the percentage of the neuronal positive control, with basal media values subtracted. The calculated EC₅₀ of the dose-response curve for this compound was 1.67μΜ.

[017] Figure 2 provides the rat PK profile of (lR,2R,3R,5R,6R)-2-amino-3-((3,4- dichlorobenzyl)oxy)-6-fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (Compound 2) after a 10 mg/kg oral dose of:

• (lR,2R,3R,5R,6R)-6-((((adamantane-l-carbonyl)oxy)methoxy)carbonyl)-2-amino-3- ((3,4-dichlorobenzyl)oxy)-6-fluorobicyclo[3.1.0]hexane-2-carboxylic acid (Compound 1) from a single experiment (n=4),

• (lR,2R,3R,5R,6R)-2-amino-3-((3,4-dichlorobenzyl)oxy)-6-fiuoro-6- ((heptyloxy)carbonyl)bicyclo [3.1.0]hexane-2-carboxylic acid (Compound 3) compiled from 2 experiments (n=7),

• (lR,2R,3R,5R,6R)-2-amino-3-((3,4-dichlorobenzyl)oxy)-6-fiuoro-6- (methoxycarbonyl)bicyclo [3.1.0]hexane-2-carboxylic acid (Compound 4) from a single experiment (n=4); and

• (lR,2R,3R,5R,6R)-2-amino-3-((3,4-dichlorobenzyl)oxy)-6-(((2,3-dihydro-lH-inden-5- yl)oxy)carbonyl)-6-fluorobicyclo[3.1.0]hexane-2-carboxylic acid (Compound 5) from a single experiment (n=4).

[018] Figure 3 provides the rat PK profile of Compound 2 after a 10 mg/kg oral dose of Compound 1.

[019] Figure 4 provides a direct comparison in a single experiment of the rat PK profile of Compound 2 after a 10 mg/kg oral dose of Compound 1 (n=4) and Compound 3 (n=4). [020] Figure 5 provides the human PK profile of Compound 2 after a 1 mg oral dose of Compound 1, Compound 3, Compound 4 and Compound 5, as adjusted based on the molecular weight of the Compound administered.

[021] Figure 6 provides the human PK profile of Compound 2 after a 1 mg oral dose of Compound 1 , as adjusted based on the molecular weight of Compound 1.

[022] Figure 7 provides a comparison of the human PK profile for Compound 2 after a 1 mg oral dose of Compound 1 and Compound 3, as adjusted based on the molecular weight of the Compound administered.

[023] Figure 8 provides the human PK profile of Compound 2 after a 1 mg oral dose of Compound 1, Compound 3, Compound 4 and Compound 5.

[024] Figure 9 provides the human PK profile of Compound 2 after a 1 mg oral dose of Compound 1.

[025] Figure 10 provides a comparison of the human PK profile for Compound 2 after a 1 mg oral dose of Compound 1 and Compound 3.

[026] Figure 11 provides the rat PK profile of Compound 2 after a 10 mg/kg oral dose of Compound 1 , as adjusted based on the molecular weight of Compound 1.

[027] Figure 12 provides a comparison of the rat PK profile of Compound 2 after a 10 mg/kg oral dose of Compound 1 and Compound 3, as adjusted based on the molecular weight of the Compound administered.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary Definitions

[028] Abbreviations used herein have their conventional meaning within the chemical and biological arts.

[029] While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the appended claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

[030] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this invention belongs.

[031] All patents and publications referred to herein are incorporated by reference.

[032] The singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise.

[033] The term "effective amount" or "therapeutically effective amount" refers to that amount of a compound described herein that is sufficient to effect the intended application including but not limited to disease treatment, as defined below. The therapeutically effective amount may vary depending upon the intended application (in vitro or in vivo), or the subject and disease condition being treated, e.g., the weight and age of the subject, the severity of the disease condition, the manner of administration and the like, which can readily be determined by one of ordinary skill in the art. The term also applies to a dose that will induce a particular response in target cells, e.g. reduction of platelet adhesion and/or cell migration. The specific dose will vary depending on the particular compounds chosen, the dosing regimen to be followed, whether it is administered in combination with other compounds, timing of administration, the tissue to which it is administered, and the physical delivery system in which it is carried.

[034] As used herein, "treatment" or "treating," or "palliating" or "ameliorating" is used interchangeably herein. These terms refer to an approach for obtaining beneficial or desired results including but not limited to therapeutic benefit and/or a prophylactic benefit. By therapeutic benefit is meant eradication or amelioration of the underlying disorder being treated. Also, a therapeutic benefit is achieved with the eradication or amelioration of one or more of the physiological symptoms associated with the underlying disorder such that an improvement is observed in the patient, notwithstanding that the patient may still be afflicted with the underlying disorder. For prophylactic benefit, the compositions may be

administered to a patient at risk of developing a particular disease, or to a patient reporting one or more of the physiological symptoms of a disease, even though a diagnosis of this disease may not have been made. The treatment or amelioration of symptoms can be based on objective or subjective parameters; including the results of a physical examination, functional (self) evaluation, and/or any form of vision evaluation.

[035] The "therapeutic effect" as used herein, encompasses a therapeutic benefit and/or a prophylactic benefit as described above. A prophylactic effect includes delaying or eliminating the appearance of a disease or condition, delaying or eliminating the onset of symptoms of a disease or condition, slowing, halting, or reversing the progression of a disease or condition, or any combination thereof.

[036] The terms "co-administration," "administered in combination with," and their grammatical equivalents, as used herein, encompass the administration of two or more agents to a subject so that both agents and/or their metabolites are present in the subject at the same time. Co-administration includes simultaneous administration in separate compositions, administration at different times in separate compositions, or administration in a composition in which both agents are present.

[037] "Subject" refers to an animal, such as a mammal, for example a human. The methods described herein can be useful in both human therapeutics and veterinary applications. In some embodiments, the patient is a mammal, and in some embodiments, the patient is human.

[038] "Prodrug" is meant to indicate a compound that may be converted under

physiological conditions or by solvolysis to a biologically active compound described herein. Thus, the term "prodrug" refers to a precursor of a biologically active compound that is pharmaceutically acceptable. A prodrug may be inactive when administered to a subject, but is converted in vivo to an active compound, for example, by hydrolysis. The term "prodrug" is also meant to include any covalently bonded carriers, which release the active Compound in vivo when such prodrug is administered to a mammalian subject. Prodrugs of an active compound, as described herein, may be prepared by modifying functional groups present in the active Compound in such a way that the modifications are cleaved, either in routine manipulation or in vivo, to the parent active compound. Prodrugs include compounds wherein a hydroxy, amino or mercapto group is bonded to any group that, when the prodrug of the active Compound is administered to a mammalian subject, cleaves to form a free hydroxy, free amino or free mercapto group, respectively. Examples of prodrugs include, but are not limited to, acetate, formate and benzoate derivatives of an alcohol or acetamide, formamide and benzamide derivatives of an amine functional group in the active compound and the like.

[039] The term "in vivo" refers to an event that takes place in a subject's body. [040] The term "in vitro" refers to an event that takes places outside of a subject's body. For example, an in vitro assay encompasses any assay run outside of a subject assay. In vitro assays encompass cell-based assays in which cells alive or dead are employed. In vitro assays also encompass a cell-free assay in which no intact cells are employed.

[041] A chiral center in the compound described herein includes all possible stereoisomers of the compound, including compositions comprising the racemic mixture of the two enantiomers, as well as compositions comprising each enantiomer individually, substantially free of the other enantiomer. Thus, for example, contemplated herein is a composition comprising the S enantiomer of a compound substantially free of the R enantiomer, or the R enantiomer substantially free of the S enantiomer. If the named compound comprises more than one chiral center, the scope of the present disclosure also includes compositions comprising mixtures of varying proportions between the diastereomers, as well as

compositions comprising one or more diastereomers substantially free of one or more of the other diastereomers. By "substantially free" it is meant that the composition comprises less than 25%, 15%, 10%>, 8%, 5%, 3%, or less than 1% of the minor enantiomer or

diastereomer(s). Methods for synthesizing, isolating, preparing, and administering various stereoisomers are known in the art.

[042] The term "pharmaceutically acceptable salts" is meant to include salts of active compounds which are prepared with relatively nontoxic acids or bases, depending on the particular substituent moieties found on the compounds described herein. When compounds of the present invention contain relatively acidic functionalities, base addition salts can be obtained by contacting the neutral form of such compounds with a sufficient amount of the desired base, either neat or in a suitable inert solvent. Organic and inorganic counter ions are well known in the art and include, by way of example only, sodium, potassium, calcium, magnesium, ammonium, tetraalkylammonium, and the like; and when the molecule contains a basic functionality, salts of organic or inorganic acids, such as hydrochloride,

hydrobromide, tartrate, mesylate, acetate, maleate, oxalate and the like.

[043] Examples of pharmaceutically acceptable base addition salts include sodium, potassium, calcium, ammonium, organic amino, or magnesium salt, or a similar salt. When compounds of the present invention contain relatively basic functionalities, acid addition salts can be obtained by contacting the neutral form of such compounds with a sufficient amount of the desired acid, either neat or in a suitable inert solvent. [044] Examples of pharmaceutically acceptable acid addition salts include those derived from inorganic acids like hydrochloric, hydrobromic, nitric, carbonic,

monohydrogencarbonic, phosphoric, monohydrogenphosphoric, dihydrogenphosphoric, sulfuric, monohydrogensulfuric, hydriodic, or phosphorous acids and the like, as well as the salts derived from relatively nontoxic organic acids like acetic, propionic, isobutyric, maleic, malonic, benzoic, succinic, suberic, fumaric, lactic, mandelic, phthalic, benzenesulfonic, p- tolylsulfonic, citric, tartaric, methanesulfonic, and the like.

[045] Also included are salts of amino acids such as arginate and the like, and salts of organic acids like glucuronic or galactunoric acids and the like. Certain specific compounds of the present invention contain both basic and acidic functionalities that allow the compounds to be converted into either base or acid addition salts.

[046] In some embodiments of the invention described herein, pharmaceutically acceptable salts include the conventional non-toxic salts or the quaternary ammonium salts of the parent compound formed, for example, from non-toxic inorganic or organic acids.

[047] Conventional non-toxic salts include, but are not limited to, those derived from inorganic acids such as hydrochloric, hydrobromic, sulfuric with replacement of one or both protons, sulfamic, phosphoric with replacement of one or both protons, e.g. orthophosphoric, or metaphosphoric, or pyrophosphoric and nitric; and the salts prepared from organic acids such as acetic, propionic, succinic, glycolic, stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, sulfanilic, 2- acetoxybenzoic, embonic, nicotinic, isonicotinic and amino acid salts, cyclamate salts, fumaric, toluenesulfonic, methanesulfonic, N-substituted sulphamic, ethane disulfonic, oxalic, and isethionic, and the like.

[048] Also, such conventional non-toxic salts include those derived from inorganic acids such as non toxic metals derived from group la, lb, Ila and lib in the periodic table. For example, lithium, sodium, or potassium, magnesium, calcium, zinc salts, or ammonium salts such as those derived from mono, di and trialkyl amines. For example methyl, ethyl, diethyl, triethyl, ethanol, diethanol or triethanol amines or quaternary ammonium hydroxides.

[049] The pharmaceutically acceptable salts of the present invention can be synthesized from the parent compound which contains a basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent, or in a mixture of the two; generally, nonaqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile. Lists of suitable salts are found in Remington s Pharmaceutical Sciences, 17th ed., Mack Publishing Company, Easton, Pa., 1985, p. 1418, which is hereby incorporated by reference.

[050] As used herein, the term "solvate" means a compound, or a salt thereof, that further includes a stoichiometric or non-stoichiometric amount of solvent bound by non-covalent intermolecular forces. Where the solvent is water, the solvate is a hydrate.

[051] As used herein, the term "analog thereof in the context of the compounds disclosed herein includes diastereomers, hydrates, solvates, salts, prodrugs, and N-oxides or S-oxides of the compounds.

[052] The present invention also includes isotopically labeled compounds, which are identical to those recited in the disclosure, but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature. These isotopically labeled compounds may show greater stability and/or may be used as imaging agents. Examples of isotopes that can be

incorporated into compounds of the present invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, sulfur, fluorine, chlorine, bromine and iodine such as ²H, ³H, ⁿC, ¹³C, ¹⁴C, ¹⁵N, ⁿO, ¹⁷0, ¹⁸0, ³¹P, ³²P, ³⁵S, ¹⁶F, ¹⁸F, ³⁶C1, ⁷⁶Br and ¹²³I respectively.

[053] "Neurogenesis" is defined herein as proliferation, differentiation, migration and/or survival of a neural cell in vivo or in vitro. In various embodiments, the neural cell is an adult, fetal, or embryonic neural stem cell or population of cells. The cells may be located in the central nervous system or elsewhere in an animal or human being. The cells may also be in a tissue, such as neural tissue. In some embodiments, the neural cell is an adult, fetal, or embryonic progenitor cell or population of cells, or a population of cells comprising a mixture of stem cells and progenitor cells. Neural cells include all brain stem cells, all brain progenitor cells, and all brain precursor cells. Neurogenesis includes neurogenesis as it occurs during normal development, as well as neural regeneration that occurs following disease, damage or therapeutic intervention, such as by the treatment described herein.

[054] A "neurogenic agent" is defined as a chemical agent or reagent that can promote, stimulate, or otherwise increase the amount or degree or nature of neurogenesis in vivo or ex vivo or in vitro relative to the amount, degree, or nature of neurogenesis in the absence of the agent or reagent. In some embodiments, treatment with a neurogenic agent increases neurogenesis if it promotes neurogenesis by about 5%, about 10%, about 25%, about 50%>, about 100%), about 500%>, or more in comparison to the amount, degree, and/or nature of neurogenesis in the absence of the agent, under the conditions of the method used to detect or determine neurogenesis. As described herein, Compound 1 is in a pharmaceutically acceptable formulation, that promotes, stimulates, or otherwise increases the amount or degree or nature of neurogenesis is a neurogenic agent.

[055] The terms "neurogenic modulators" or "neurogenic modulating agents" are defined as an agent when used alone or in combination with one or more other agents induces a change in neurogenesis. In some embodiments, administering "neurogenic modulators" or

"neurogenic modulating agents" according to methods provided herein changes neurogenesis in a target tissue and/or cell-type by about 20%, about 25%, about 30%, about 40%>, about 50%, about 75%, or about 90% or more in comparison to the absence of the combination. In further embodiments, neurogenesis is modulated by about 95% or by about 99% or more. Preferably the modulation noted is an increase in neurogenesis.

[056] The term "stem cell" (or neural stem cell (NSC)), as used herein, refers to an undifferentiated cell that is capable of self-renewal and differentiation into neurons, astrocytes, and/or oligodendrocytes.

[057] The term "progenitor cell" (e.g., neural progenitor cell), as used herein, refers to a cell derived from a stem cell that is not itself a stem cell. Some progenitor cells can produce progeny that are capable of differentiating into more than one cell type.

[058] The term "mGluR2 and/or mGluR3" refers to the metabotropic glutamate receptors (mGluRs) in Group II. In some embodiments, the compound disclosed herein is an mGluR2 and/or mGluR3 antagonist.

Exemplary Compounds

[059] The present invention is directed to Compound 1 having the following structure:

[060] The chemical name for Compound 1 is (lR,2R,3R,5R,6R)-6-((((adamantane-l- carbonyl)oxy)methoxy)carbonyl)-2-amino-3-((3,4-dichlorobenzyl)oxy)-6- fluorobicyclo[3.1.0]hexane-2-carboxylic acid. The Chemical Formula of Compound 1 is: C₂₇H₃₀CI₂FNO₇. Compound 1 has an Exact Mass of 569.14. Also included in the invention described herein are analogs of Compound 1.

[061] In some embodiments, Compound 1 has a bioavailability of greater than about 10%. In some embodiments, the bioavailability of Compound 1 is between about 10% to about 30%, or about 20% to about 40%, or about 30% to about 50%, or about 40% to about 60%, or about 50%) to about 70%>, or about 60%> to about 90%>. In some specific embodiments the bioavailability of Compound 1 is greater than about 50%. In other specific embodiments, the bioavailability of Compound 1 is greater than about 60%. In yet other specific embodiments the bioavailability of Compound 1 is between about 80% and 90%. In still further embodiments, the bioavailability of Compound 1 is between about 40% and 50%.

[062] In some embodiments, Compound 1 provides a rapid onset of anti-depressant response when administered to a subject.

[063] In some embodiments, Compound 1 has a pharmacodynamic half-life of greater than 2 hours, greater than 4 hours, greater than 8 hours, greater than 24 hrs, greater than 2 days, greater than 4 days, greater than 7 days systemically. In some embodiments, the systemic pharmacodynamic half-life of Compound 1 is between 2 hours and 8 hours. In other embodiments, the systemic pharmacodynamic half-life of Compound 1 is between 2 days and 7 days.

[064] In some embodiments, Compound 1 has a pharmacodynamic half-life of greater than 2 hours, greater than 4 hours, greater than 8 hours, greater than 24 hrs, greater than 2 days, greater than 4 days, greater than 7 days in the brain. In some embodiments, the

pharmacodynamic half- life of Compound 1 in the brain is between 2 hours and 8 hours. In other embodiments, the pharmacodynamic half-life of Compound 1 in the brain is between 2 days and 7 days.

[065] As used herein, the term Compound 2 refers to a compound having the following structure:

[066] The scientific name for Compound 2 is (lR,2R,3R,5R,6R)-2-amino-3-((3,4- dichlorobenzyl)oxy)-6-fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid. The Chemical Formula of Compound 2 is: C₁₅H₁₄CI₂FNO₅. Compound 2 has an Exact Mass of 377.02

[067] As used herein, the term Compound 3 refers to a compound having the following structure:

[068] The scientific name for Compound 3 is (lR,2R,3R,5R,6R)-2-amino-3-((3,4- dichlorobenzyl)oxy)-6-fluoro-6-((heptyloxy)carbonyl)bicyclo [3.1.0]hexane-2-carboxylic acid/ The Chemical Formula of Compound 3 is: C₂₂H₂₈CI₂FNO₅. Compound 3 has an Exact Mass of 475.13.

[069] As used herein, the term Compound 4 refers to a compound having the following structure:

[070] The scientific name for Compound 4 is (lR,2R,3R,5R,6R)-2-amino-3-((3,4- dichlorobenzyl)oxy)-6-fiuoro-6-(methoxycarbonyl)bicyclo [3.1.0]hexane-2-carboxylic acid hydrochloride. The Chemical Formula of Compound 4 is: C₁₆H₁₇CI₃FNO₅. Compound 4 has an Exact Mass of 427.02.

[071] As used herein, the term Compound 5 refers to a compound having the following structure:

[072] The scientific name for Compound 5 is (lR,2R,3R,5R,6R)-2-amino-3-(3,4- dichlorobenzyloxy)-6-((2,3-dihydro-lH-inden-5-yloxy) carbonyl)-6- fluorobicyclo[3.1.0]hexane-2-carboxylic acid. The Chemical Formula of Compound 5 is: C24H22CI2FNO5. Compound 5 has an Exact Mass of 493.09.

Exemplary Pharmaceutical Compositions

[073] In some embodiments, the compound of this invention used in the methods described herein, is in the form of a pharmaceutical composition that includes at least one

pharmaceutically acceptable excipient. As used herein, the term "pharmaceutically acceptable excipient" includes any excipient known in the field as suitable for pharmaceutical applications. Suitable pharmaceutical excipients and formulations are known in the art and are described, for example, in Remington's Pharmaceutical Sciences (19th ed.) (Genarro, ed. (1995) Mack Publishing Co., Easton, Pa.). Pharmaceutical carriers may be chosen by a skilled person based upon the intended mode of administration of compound. The pharmaceutically acceptable carrier may include, for example, disintegrants, binders, lubricants, glidants, emollients, humectants, thickeners, silicones, flavoring agents, and/or water.

[074] The compound may be incorporated with excipients and administered in the form of ingestible tablets, chewable tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, or any other form known in the pharmaceutical arts. The pharmaceutical compositions may also be formulated in a sustained release or a delayed release form.

Sustained release and delayed release compositions are known in the art. Alternatively, the compositions may be a quick release formulation.

[075] An effective amount of a composition may vary based on a variety of factors, including but not limited to, the activity of the active compound, the physiological characteristics of the subject, the nature of the condition to be treated, and the route and/or method of administration. The disclosed methods typically involve the administration in a dosage range of 0.001 mg/kg/day to 4000 mg/kg/day or in a dosage range of 0.05 to 500 mg/kg/day. Advantageously, methods described herein allow treatment of indications with reductions in side effects, dosage levels, dosage frequency, treatment duration, tolerability, and/or other factors.

[076] Depending on the desired clinical result, the disclosed neurogenic agent or pharmaceutical compositions are administered by any means suitable for achieving a desired effect. Various delivery methods are known in the art and can be used to deliver the agent to a subject or to NSCs or progenitor cells within a tissue of interest. The delivery method will depend on factors such as the tissue of interest, the nature of the compound (e.g., its stability and ability to cross the blood-brain barrier), and the duration of the treatment, among other factors. For example, an osmotic minipump can be implanted to facilitate administration of the Compound into a neurogenic region, such as the lateral ventricle. Alternatively, compounds can be administered by direct injection into the cerebrospinal fluid of the brain or spinal column, or into the eye. Administration to the eyes may also be in the form of ocular drops. Compounds can also be administered into the periphery (such as by intravenous or subcutaneous injection, oral or nasal delivery), and subsequently cross the blood-brain barrier.

[077] In various embodiments, the disclosed agents or pharmaceutical compositions are administered in a manner that allows them to cross the blood-brain barrier and in a non- limiting embodiment, contact the subventricular zone (SVZ) of the lateral ventricles and/or the dentate gyrus of the hippocampus. Examples of routes of administration include parenteral, e.g., intravenous, intradermal, subcutaneous, oral, inhalation, transdermal (topical), transmucosal, and rectal administration. Intranasal administration generally includes, but is not limited to, inhalation of aerosol suspensions for delivery of compositions to the nasal mucosa, trachea and bronchioli.

[078] In some embodiments, the compound combinations are administered so as to either pass through or by-pass the blood-brain barrier. Methods for allowing factors to pass through the blood-brain barrier are known in the art, and include minimizing the size of the factor, providing hydrophobic factors which facilitate passage, and conjugating the compound to a carrier molecule that has substantial permeability across the blood brain barrier. In some instances, the combination of compounds can be administered by a surgical procedure implanting a catheter coupled to a pump device. The pump device can also be implanted or be extracorporally positioned. Administration of the compound can be in intermittent pulses or as a continuous infusion. [079] Devices for injection to discrete areas of the brain are known in the art. In certain embodiments, the Compound is administered locally to the ventricle of the brain, substantia nigra, striatum, locus ceruleous, nucleus basalis Meynert, pedunculopontine nucleus, cerebral cortex, and/or spinal cord by, e.g., injection. Methods, compositions, and devices for delivering therapeutics, including therapeutics for the treatment of diseases and conditions of the CNS and PNS, are known in the art.

[080] In some embodiments, the delivery or targeting of a compound, to a neurogenic region, such as the dentate gyrus or the subventricular zone, enhances efficacy and reduces side effects compared to known methods involving administration with the same or similar compounds.

Examples of Additional Therapeutics

[081] In some embodiments, the methods may comprise the use of one or more agents reported as anti-depressant agents. In these embodiments, Compound 1 may be coadministered with one or more reported anti-depressant agents known in the art. Antidepressant agents known in the art include, but are not limited to, SSRIs, SNRIs, SSNRIs, triple uptake inhibitors, agents like dehydroepiandrosterone (DHEA) and DHEA Sulfate, Monoamine Oxidase inhibitors (MAO), Vlb antagonists, opioids, NMDA antagonists, Angiotensin modulators, Psychostimulants, Melatonin receptor agonists,

Muscarinic/acetylcholine receptor modulators, Phosphodiesterase (PDE) inhibitors, Gama- aminobutyric acid (GAB A) receptor modulators, 5-Hydroxytryptamine receptor modulators (5HT), Peroxisome proliferatory-activated receptor (PPAR) modulators, Melatonergic Agonist/5-HT2C antagonists (such as agomelatine and related melatonin receptor 1& 2 modulators including BCI-952), and tricyclics.

[082] Non-limiting examples of SSRI (selective serotonine reuptake inhibitor) useful in the combinations disclosed herein are fluoxetine (Prozac^®), citalopram (Celexa), escitalopram (Lexapro), fluvoxamine or fluvoxamine maleate (CAS RN: 61718-82-9) and Luvox^®, paroxetine (Paxil^®), or sertraline (Zoloft^®); the compound nefazodone (Serozone^®).

[083] Non-limiting examples of SNRI (selective norepinephrine reuptake inhibitors) useful in the combinations disclosed herein are reboxetine (Edronax^®) and atomoxetine (Strattera^®). [084] Non-limiting examples of SSNRI (selective serotonin & norepinephrine reuptake inhibitors) useful in the combinations disclosed herein are venlafaxine (Effexor^®), and its reported metabolite desvenlafaxine, or duloxetine (Cymbalta^®).

[085] Non-limiting examples of serotonin, noradrenaline, and dopamine (triple uptake) inhibitors useful in the combinations disclosed herein are DOV 102,677, DOV 102,677, DOV 216,303, DOV 216,303, DOV 21,947, NS-2330 (CAS RN 402856-42-2), and NS 2359 (CAS RN 843660-54-8).

[086] Non-limiting examples of tricyclic compounds useful in the combinations disclosed herein are amitriptyline, desipramine, doxepin, imipramine, and nortriptyline.

[087] Non-limiting examples of psychostimulants useful in the combinations disclosed herein are dextroamphetamine and methylphenidate.

[088] Non- limiting examples of MAO inhibitors useful in the combinations disclosed herein are selegiline (Emsam^®); an ampakine such as CX516 (or Ampalex, CAS RN: 154235-83-3), CX546 (or l-(l,4-benzodioxan-6-ylcarbonyl)piperidine), and CX614 (CAS RN 191744-13-5) from Cortex Pharmaceuticals.

[089] Non- limiting examples of Vlb antagonist useful in the combinations disclosed herein are SSR149415 ((2S,4R)-1 -[5-Chloro- 1 -[(2,4-dimethoxyphenyl)sulfonyl]-3-(2-methoxy- phenyl)-2-oxo-2,3-dihydro-lH-indol-3-yl]-4-hydroxy-N,N-dimethyl-2-pyrrolidine carboxamide).

[090] Other compounds useful in the combinations disclosed herein are NMDA antagonists and opioids (including but not limited meperidine, Methadone, Dextropropoxyphene, Tramadol, Ketobemidone, Ketamine, dextromethorphan, phencyclidine and nitrous oxide), mGluR5 modulators, acetylchoine esterase inhibitors, including but not limited to Aricept, and muscarinic agonists/positive allosteric modulators (PAMs), more specifically Ml and M3.

[091] Yet other compounds useful in the combinations disclosed herein are fluorinated pyrimidines, including but not limited to flurouracil (5-FU) and alkylating agents, including but not limited to Temozolomide.

[092] In some embodiments, Compound 1 , optionally in combination with one or more other agents, results in improved efficacy, fewer side effects, lower effective dosages, less frequent dosing, and/or other desirable effects relative to use of Compound 1 individually (such as at higher doses). In some embodiments, this is due to synergistic activities and/or the targeting of molecules and/or activities that are differentially expressed in particular tissues and/or cell-types.

Exemplary Treatment Methods

[093] The inventors have unexpectedly discovered that Compound 1 , alone or in the combinations contemplated herein, is useful as a pharmaceutical to treat and/or prevent diseases and/or conditions of the central and peripheral nervous system. In some

embodiments of the invention disclosed herein, Compound 1 is administered to a subject in a pharmaceutical composition.

[094] In various embodiments, the compound and compositions described herein can be used to treat diseases, disorders, and conditions of the central and/or peripheral nervous systems (CNS and PNS, respectively) by administering Compound 1, optionally in combination with another therapeutic, including but not limited to an mGluR2 and/or mGluR3 antagonist and/or another agent (CNS, neurogenic, anti-astrogenic, anti-nausea, etc). The amount of Compound 1 , optionally in combination with another agent, may be any that results in a measurable relief of a disease condition like those described herein.

[095] Also provided herein are methods for lessening and/or reducing a decline or decrease of cognitive function in an animal or human subject due to a nervous system disorder, disease or condition by administering to the subject a therapeutically effective amount of Compound 1 or Compound 1 in a pharmaceutically acceptable formulation. In some cases, the method may be applied to maintain and/or stabilize cognitive function in the subject. The cognitive impairment may be the result of chronic infection, toxic disorders, neurodegenerative disorders and combinations thereof.

[096] In addition, provided herein are methods for treating a subject suffering from cognitive impairment due to a non-disease state. The methods include administering to the subject a therapeutically effective amount of Compound 1 or Compound 1 in a

pharmaceutically acceptable formulation. Non-limiting examples of non-disease states include cognitive impairment due to aging, chemotherapy and radiation therapy.

[097] In some embodiments, the invention described herein provides a novel method for treating a mental disorder with a therapeutically effective amount of Compound 1 or

Compound 1 in a pharmaceutically acceptable formulation. In some embodiments, the method may be used to moderate or alleviate the mental disorder in an animal or human subject. Non-limiting examples of a mental disorder include an anxiety disorder and/or a mood disorder including depression. In other embodiments, the method may be used to improve, maintain, or stabilize an affective disorder in a subject.

[098] Disclosed herein are also methods for identifying an animal or human subject suffering from one or more diseases, disorders, or conditions, or a symptom thereof, and administering to the subject a therapeutically effective amount of Compound 1 or Compound 1 in a pharmaceutically acceptable formulation. In some embodiments, the disclosed methods include identification of a subject as in need of an increase in neurogenesis and administering a therapeutically effective amount of Compound 1 or Compound 1 in a pharmaceutically acceptable formulation. In other embodiments, the subject is a mammal, more preferably a human being.

[099] In some embodiments, Compound 1 is used to stimulate or increase neurogenesis in a cell or tissue in a subject. In some embodiments, the subject may have a condition affecting normal neurogenesis whereby stimulating or increasing neurogenesis improves the condition. The cell or tissue to be treated may exhibit the effects of insufficient amounts of, inadequate levels of, or aberrant neurogenesis. In some embodiments, the cell or tissue exhibits decreased neurogenesis or is subject to an agent that decreases or inhibits neurogenesis. In some embodiments, the subject may be one that has a disease, condition or disorder which results in suppressed or decreased neurogenesis. In some embodiments, the subject is in need of neurogenesis and has been diagnosed with a disease, condition, or injury of the central or peripheral nervous system. In one aspect, the subject has one or more chemical addictions or dependencies.

[0100] In some embodiments, the aberrant neurogenesis may be attributed to epilepsy, or a condition associated with epilepsy as non-limiting examples. In these embodiments, an increase in neurogenesis would decrease or alleviate the aberrant neurogenic symptoms in the subject.

[0101] Non- limiting examples of symptoms that may be treated with the methods described herein include abnormal behavior, abnormal movement, hyperactivity, hallucinations, acute delusions, combativeness, hostility, negativism, withdrawal, seclusion, memory defects, sensory defects, cognitive defects, pain and tension. Non-limiting examples of abnormal behavior include irritability, poor impulse control, distractibility, and aggressiveness. [0102] As a non- limiting example, an improvement in the Hamilton depression scale (HAM- D) score for depression may be used to determine (such as quantitatively) or detect (such as qualitatively) a measurable level of improvement in the depression of a subject.

[0103] Also included in the invention described herein is the treatment of diseases and conditions including, but not limited to, neurodegenerative disorders and neural diseases, such as dementias (e.g., senile dementia, memory disturbances/memory loss, dementias caused by neurodegenerative disorders (e.g., Alzheimer's, Parkinson's disease, Parkinson's disorders, Huntington's disease (Huntington's Chorea), Lou Gehrig's disease, multiple sclerosis, Pick's disease, Parkinsonism dementia syndrome), progressive subcortical gliosis, progressive supranuclear palsy, thalmic degeneration syndrome, hereditary aphasia, amyotrophic lateral sclerosis, Shy-Drager syndrome, and Lewy body disease; vascular conditions (e.g., infarcts, hemorrhage, cardiac disorders); mixed vascular and Alzheimer's; bacterial meningitis; Creutzfeld- Jacob Disease; and Cushing's disease.

[0104] The disclosed embodiments also provide for the treatment of a nervous system disorder related to neural damage, cellular degeneration, a psychiatric condition, cellular (neurological) trauma and/or injury (e.g., subdural hematoma or traumatic brain injury), toxic chemicals (e.g., heavy metals, alcohol, some medications), CNS hypoxia, or other neurologically related conditions. In practice, the disclosed compositions and methods may be applied to a subject or patient afflicted with, or diagnosed with, one or more central or peripheral nervous system disorders in any combination. Diagnosis may be performed by a skilled person in the applicable fields using known and routine methodologies which identify and/or distinguish these nervous system disorders from other conditions.

[0105] Non-limiting examples of nervous system disorders related to cellular degeneration include neurodegenerative disorders, neural stem cell disorders, neural progenitor cell disorders, degenerative diseases of the retina, and ischemic disorders. In some embodiments, an ischemic disorder comprises an insufficiency, or lack, of oxygen or angiogenesis, and non- limiting example include spinal ischemia, ischemic stroke, cerebral infarction, multi-infarct dementia. While these conditions may be present individually in a subject or patient, the disclosed methods also provide for the treatment of a subject or patient afflicted with, or diagnosed with, more than one of these conditions in any combination.

[0106] Non-limiting embodiments of nervous system disorders related to a psychiatric condition include neuropsychiatric disorders and affective disorders. As used herein, an affective disorder refers to a disorder of mood such as, but not limited to, depression, post- traumatic stress disorder (PTSD), hypomania, panic attacks, excessive elation, bipolar depression, bipolar disorder (manic-depression), and seasonal mood (or affective) disorder. Other non-limiting embodiments include schizophrenia and other psychoses, lissencephaly syndrome, anxiety syndromes, anxiety disorders, phobias, stress and related syndromes (e.g., panic disorder, phobias, adjustment disorders, migraines), cognitive function disorders, aggression, drug and alcohol abuse, drug addiction, and drug-induced neurological damage, obsessive compulsive behavior syndromes, borderline personality disorder, non-senile dementia, post-pain depression, post-partum depression, and cerebral palsy.

[0107] Examples of nervous system disorders related to cellular or tissue trauma and/or injury include, but are not limited to, neurological traumas and injuries, surgery related trauma and/or injury, retinal injury and trauma, injury related to epilepsy, cord injury, spinal cord injury, brain injury, brain surgery, trauma related brain injury, trauma related to spinal cord injury, brain injury related to cancer treatment, spinal cord injury related to cancer treatment, brain injury related to infection, brain injury related to inflammation, spinal cord injury related to infection, spinal cord injury related to inflammation, brain injury related to environmental toxin, brain injury related to substance abuse, and spinal cord injury related to environmental toxin.

[0108] Non-limiting examples of nervous system disorders related to other neurologically related conditions include learning disorders, memory disorders, age-associated memory impairment (AAMI) or age-related memory loss, autism, learning or attention deficit disorders (ADD or attention deficit hyperactivity disorder, ADHD), narcolepsy, sleep disorders and sleep deprivation (e.g., insomnia, chronic fatigue syndrome), cognitive disorders, epilepsy, injury related to epilepsy, and temporal lobe epilepsy.

[0109] Other non-limiting examples of diseases and conditions treatable by the methods described herein include, but are not limited to, hormonal changes (e.g., depression and other mood disorders associated with puberty, pregnancy, or aging (e.g., menopause)); and lack of exercise (e.g., depression or other mental disorders in elderly, paralyzed, or physically handicapped patients); infections (e.g., HIV); genetic abnormalities (Down syndrome);

metabolic abnormalities (e.g., vitamin B12 or folate deficiency); hydrocephalus; memory loss separate from dementia, including mild cognitive impairment (MCI), age-related cognitive decline, and memory loss resulting from the use of general anesthetics, chemotherapy, radiation treatment, post-surgical trauma, or therapeutic intervention; and diseases of the of the peripheral nervous system (PNS), including but not limited to, PNS neuropathies (e.g., vascular neuropathies, diabetic neuropathies, amyloid neuropathies, and the like), neuralgias, neoplasms, myelin-related diseases, etc.

[0110] Additionally, the disclosed methods provide for the application of Compound 1, optionally in combination with another mGluR2 and/or mGluR3 agent and/or another neurogenic agent, to treat a subject or patient for a condition due to the anti-neurogenic effects of an opiate or opioid based analgesic. In some embodiments, the administration of an opiate or opioid based analgesic, such as an opiate like morphine or other opioid receptor agonist, to a subject or patient results in a decrease in, or inhibition of, neurogenesis. The administration of a compound, optionally in combination with a neurogenic agent, with an opiate or opioid based analgesic would reduce the anti-neurogenic effect.

[0111] The disclosed embodiments include a method of treating post operative pain in a subject or patient by combining administration of an opiate or opioid based analgesic with a compound, optionally in combination with an mGluR2 and/or mGluR3 agent and/or a neurogenic agent. The analgesic may have been administered before, simultaneously with, or after the compound, alone or in combination with a neurogenic agent. In some cases, the analgesic or opioid receptor agonist is morphine or another opiate.

[0112] Compounds and compositions disclosed herein can also be used to treat diseases of the peripheral nervous system (PNS), including but not limited to, PNS neuropathies (e.g., vascular neuropathies, diabetic neuropathies, amyloid neuropathies, and the like), neuralgias, neoplasms and myelin-related diseases as non-limiting examples.

[0113] In some embodiments, a compound of this invention, optionally in combination with another agent, used in the methods described herein, is in the form of compositions that include at least one pharmaceutically acceptable excipient. Suitable pharmaceutical excipients and formulations are known in the art and are described, for example, in

Remington's Pharmaceutical Sciences (19th ed.) (Genarro, ed. (1995) Mack Publishing Co., Easton, Pa.). Pharmaceutical carriers may be chosen by a skilled person based upon the intended mode of administration of an mGluR2 and/or mGluR3 agonist, antagonist, Negative Allosteric Modulators (NAM), Positive Allosteric Modulators (PAM) or allosteric agonist. The pharmaceutically acceptable carrier may include, for example, disintegrants, binders, lubricants, glidants, emollients, humectants, thickeners, silicones, flavoring agents, and water.

[0114] The compound may be incorporated with excipients and administered in the form of ingestible tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, or any other form known in the pharmaceutical arts. The pharmaceutical compositions may also be formulated in a sustained release form. Sustained release compositions, enteric coatings, and the like are known in the art. Alternatively, the compositions may be a quick release

formulation.

[0115] In some embodiments, methods of treatment disclosed herein comprise the step of administering to the subject or patient the compound, optionally in combination with another agent, for a time and at a concentration sufficient to treat the condition targeted for treatment.

[0116] The disclosed methods can be applied to individuals having, or who are likely to develop, disorders relating to neural degeneration, neural damage and/or neural

demyelination. In some embodiments, a method comprises selecting a population or sub- population of patients, or selecting an individual patient, that is more amenable to treatment and/or less susceptible to side effects than other patients having the same disease or

condition. For example, in some embodiments, a sub-population of patients is identified as being more amenable to neurogenesis by taking a cell or tissue sample from prospective patients, isolating and culturing neural cells from the sample, and determining the effect of a compound, optionally in combination with a neurogenic agent, on the degree or nature of neurogenesis, thereby allowing selection of patients for which the compound or combination has a substantial effect on neurogenesis. Advantageously, the selection step(s) results in more effective treatment for the disease or condition that known methods using the same or similar compounds.

Exemplary Syntheses

Synthesis of Compound 1

[0117] The process used for the preparation of (lR,2R,3R,5R,6R)-6-((((adamantane-l- carbonyl)oxy)methoxy)carbonyl)-2-amino-3-((3,4-dichlorobenzyl)oxy)-6- fluorobic clo[3.1.0]hexane-2-carboxylic acid is as follows:

ChesEik ! ^nnuia: C_i;; _;60. CheHskaS ofmuia: Οΐ5;ί¾0 CheHskaS ofmuia: C_{; ; !} O0;

Mt»iee»l*r Weight: oSet-uis.r Wei§hK 165 Mottea!sr Weight: «8.72

[0118] To a stirred solution of adamantane-l-carboxylic acid (0.2g, 1.1 lmmol) in a mixture of CH₂Cl₂:Water (5mL, 1 : 1) under nitrogen atmosphere were added NaHC0₃ (0.429g, 5.1 lmmol), tetrabutyl ammonium hydrogensulfate (0.0433g, 0.127mmol) and chloromethyl chlorosulfate (0.22mL, 2.20mmol) at 0°C. The reaction mixture was stirred at 0°C for 30 min, slowly warmed to RT and stirred for another 4 h. The reaction mixture was diluted with water (20mL) and extracted with CH₂CI₂ (2 x 20mL). The combined extracts was dried over Na₂S0₄ and concentrated under reduced pressure to afford chloromethly adamantane-1- carboxylate (0.23g, crude) as colorless liquid. This crude material was used in the next step without purification. 1H NMR (500MHz, CDC1₃): <½.70 (s, 2H), 2.03 (s, 3H), 1.93-1.89 (m, 6H), 1.77-1.67 (m, 6H).

[0119] (lR,2R,3R,5R,6R)-6-((((adamantane-l-carbonyl)oxy)methoxy) carbonyl)-2-amino-3- -dichlorobenzyl)oxy)-6-fluorobicyclo[3.1.0]hexane-2-carboxylic acid:

[0120] To a stirred solution of (lR,2R,3R,5R,6R)-2-amino-3-(3,4-dichlorobenzyl)oxy-6- fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (Compound 2) (see, e.g., Chaki et al, MGS0039: a Potent and Selective Group II Metabotropic Glutamate Receptor Antagonist With Antidepressant-Like Activity, 46 Neuropharmacology 457 (2004) and Nakazato et al., Synthesis, In Vitro Pharmacology, Structure-Activity Relationships, and Pharmacokinetics of 3-Alkoxy-2-Amino-6-Fluorobicyclo[3.1.01Hexane-2,6-Dicarboxylic Acid Derivatives as Potent and Selective Group II Metabotropic Glutamate Receptor Antagonists, 47 J. Med. Chem. 4570 (2004)) in 1,4-dioxane (20mL) were added allyl chloroformate (1.27g, 10.6mmol) and saturated aqueous NaHC0₃ solution (13mL) at 0°C. The reaction mixture was warmed to room temperature and stirred for 18h. The progress of the reaction was monitored by TLC. The reaction mixture was diluted with water (20mL), acidified with IN HC1 (lOmL, pH=2) and extracted with ethyl acetate (3 x 15mL). The combined organic layer was washed with water (1 x lOmL), brine (1 x lOmL), dried over Na₂S0₄ and concentrated under reduced pressure. This crude product (Intermediate 1) was directly used in the next reaction.

[0121] To the above crude product in benzene (50mL) under nitrogen atmosphere were added paraformaldehyde (0.53g) and catalytic amount of TsOH monohydrate (36mg). The reaction mixture was stirred at 100°C (bath temperature) for 6h using Dean-Stark apparatus. After complete consumption of starting material by TLC, reaction mixture was diluted with water (15mL) and extracted with ethyl acetate (3 x 25mL). The combined organic layer was washed with water (1 x 20mL), brine (1 x 20mL), dried over Na₂S0₄ and concentrated under reduced pressure to afford 2.8g of light yellow color liquid (Intermediate 2) which was used in the next step without further purification.

[0122] To a stirred solution of Intermediate 2 (0.5g, -60% pure by HPLC, 0.633mmol) in DMF (50mL) under nitrogen atmosphere were added Chloromethyl adamantane-1- carboxylate (0.289g, 1.26mmol), K₂C0₃ (0.131g, 0.95mmol) and Nal (0.189g, 1.26mmol) at ambient temperature. The reaction mixture was heated to 60°C and stirred for 3h. The progress of the reaction was monitored by TLC. The reaction mixture was cooled to RT and diluted with water (20mL) and extracted with ethyl acetate (3 x 20mL). The combined organic layer was dried over Na₂S0₄ and evaporated under reduced pressure. Crude material was purified by column chromatography using hexane/EtOAc (85: 15) to Intermediate 3 (0.300g, 71.25%). 1H NMR (500 MHz, CD₃C1₃): δ 7.40 (d, J = 8.5 Hz, 1H), 7.31 (s, 1H), 7.06 (d, J = 8.5 Hz, 1H), 5.91-5.88 (m, 1H), 5.79 (s, 2H), 5.52 (d, J = 4.5 Hz, 1H), 5.31-5.19 (m, 3H), 4.63-4.59 (m, 2H), 4.51 (d, J = 12.5 Hz, 1H), 4.38 (d, J = 12.5 Hz, 1H), 4.21-4.16 (m, 1H), 2.48-2.41 (m, 2H), 2.33-2.27 (m, 1H), 2.07-2.02 (m, 4H), 1.89-1.86 (m, 6H), 1.80- 1.65 (m, 6H). MS (ESI): m/z 683 [M+18]⁺.

[0123] To a stirred solution of Intermediate 3 (300mg, 0.45mmol) in CHC1₃ (5mL) was added Pd(PPh₃)₄ (20mg) and 1,3-dimethyl barbituric acid (84mg, 0.541mmol) under argon atmosphere. The reaction mixture was stirred at room temperature for 30 min. The progress of the reaction was monitored by TLC. CHC1₃ was removed under reduced pressure and the crude product was washed with di-isopropyl ether (2 x 5mL), to which few drops of water and MeOH were added. The precipitated solid was filtered and this was washed with methanol (2 xlO mL) to afford an off-white solid, (lR,2R,3R,5R,6R)-6-((((adamantane-l- carbonyl)oxy)methoxy)carbonyl)-2-amino-3-((3,4-dichlorobenzyl)oxy)-6- fluorobicyclo[3.1.0]hexane-2-carboxylic acid (Compound 1); 165 mg, 64%. 1H NMR (500 MHz, CD₃OD): δ 7.55 (s, 1H), 7.46 (d, J = 8.5 Hz, 1H), 7.29 (d, J = 8.5 Hz, 1H), 5.83 (s, 2H), 4.60 (d, J = 12.5 Hz, 1H), 4.48 (d, J = 12.5 Hz, 1H), 4.04-3.99 (m, 1H), 2.64-2.59 (m, 1H), 2.53-2.49 (m, 1H), 2.43-2.37 (m, 2H), 2.05-2.0 (m, 3H), 1.93-1.88 (m, 6H), 1.83-1.73 (m, 6H). MS (ESI): m/z 570 [M+l]⁺ HPLC: 95.03%

Synthesis of Compound 5

[0124] Process for preparing (lR,2R,3R,5R,6R)-2-amino-3-(3,4-dichlorobenzyloxy)-6-((2,3- dihydro-lH-inden-5-yloxy) carbonyl)-6-fluorobicyclo[3.1.0]hexane-2-carboxylic acid

[0125] To a stirred solution (lR,2R,3R,5R,6R)-2-amino-3-(3,4-dichlorobenzyl)oxy-6- fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (Compound 2) {see, e.g., Chaki et al,

MGS0039: a Potent and Selective Group II Metabotropic Glutamate Receptor Antagonist With Antidepressant-Like Activity, 46 Neuropharmacology 457 (2004) and Nakazato et al., Synthesis, In Vitro Pharmacology, Structure- Activity Relationships, and Pharmacokinetics of 3-Alkoxy-2-Amino-6-Fluorobicyclo[3.1.01Hexane-2,6-Dicarboxylic Acid Derivatives as Potent and Selective Group II Metabotropic Glutamate Receptor Antagonists, 47 J. Med. Chem. 4570 (2004)); (2.0 g, 5.3mmol) in 1,4-dioxane (20mL) were added allyl chloroformate (1.27g, 10.6mmol) and saturated aqueous NaHC0₃ solution (13mL) at 0°C. The reaction mixture was warmed to room temperature and stirred for 18h.

[0126] The progress of the reaction was monitored by TLC. The reaction mixture was diluted with water (20mL), acidified with 1NHC1 (lOmL, pH=2) and extracted with ethyl acetate (3 x 15mL). The combined organic layer was washed with water (1 x lOmL), brine (1 x lOmL), dried over Na₂S0₄ and concentrated under reduced pressure. This crude product (Intermediate 1) was directly used in the next reaction.

[0127] To the above crude product in benzene (50mL) under nitrogen atmosphere were added paraformaldehyde (0.53g) and catalytic amount of TsOH monohydrate (36mg). The reaction mixture was stirred at 100°C (bath temperature) for 6h using Dean-Stark apparatus. After complete consumption of starting material by TLC, the reaction mixture was diluted with water (15mL) and extracted with ethyl acetate (3 x 25mL). The combined organic layer was washed with water (1 x 20mL), brine (1 x 20mL), dried over Na₂S0₄ and concentrated under reduced pressure to afford 2.8 g of light yellow color liquid (Intermediate 2) which was used in the next step without further purification. 1H NMR (500 MHz, CDC1₃): δ 2.16 (dd, J = 8.5, 2.5 Hz, 1 H), 2.31-2.45 (m, 3 H), 4.21-4.23 (m, 1H), 4.44 (d, J= 13 Hz, 1H), 4.56-4.63 (m, 3H), 5.20-5.31 (m, 3H), 5.53 (d, J= 4.5 Hz, 1H), 5.90-5.97 (m, 1H), 7.21 (dd, J= 8.5, 1.5 Hz, 1H), 7.45 (s, 1H), 7.49 (d, J= 8.5 Hz, 1H).

[0128] To a stirred solution of Intermediate 2 (0.5g, 1.05mmol) in DMF (lOmL) at 0°C under N₂ atmosphere were added 2,3-dihydro-lH-inden-5-ol (0.14g, 1.05mmol), HOBt (0.14g, 1.05mmol), EDC HC1 (0.60g, 3.17mmol) and NMM (0.34mL, 3.17mmol). The reaction mixture was slowly brought to RT and stirred for 18h. The progress of the reaction was monitored by TLC. The reaction mixture was diluted with water (20mL) and extracted with ethyl acetate (3 x 20mL). The combined organic layer was dried over Na₂S0₄ and the solvent was evaporated under reduced pressure. The crude product was purified by silica gel column chromatography to give Intermediate 3 (0.300g, 48%). This showed starting material impurity and was used in the next step directly without further purification. MS (ESI): m/z 607 [M+18]⁺.

[0129] To a stirred solution of Intermediate 3 (0.3g, 0.50mmol) in chloroform (5mL) were added Pd(PPh₃)₄ (0.015g) and 1,3-dimethyl barbituric acid (0.095g, 0.61mmol) under argon atmosphere and the reaction mixture was stirred at room temperature for 30 min. The progress of the reaction was monitored by TLC. Chloroform was removed under reduced pressure and the crude product was washed with diisopropyl ether (2 x 5mL) to obtain 250mg of a crude product from which 150mg was further purified by preparative HPLC to afford off-white solid (lR,2R,3R,5R,6R)-2-amino-3-(3,4-dichlorobenzyloxy)-6-((2,3-dihydro-lH- inden-5-yloxy) carbonyl)-6-fluorobicyclo[3.1.0]hexane-2-carboxylic acid (Compound 5); 40mg, 26% (calculated for 250mg of crude product). 1H NMR (500 MHz, CD₃OD): δ 7.54 (s, 1H), 7.48 (d, J = 8.0 Hz, 1H), 7.26 (d, J = 7.0 Hz, 1H), 7.22 (d, J = 8.0 Hz, 1H), 6.98 (s, 1H), 6.86 (d, J = 7.0 Hz, 1H), 4.61 (d, J = 12.0 Hz, 1H), 4.59 (d, J = 12.0 Hz, 1H), 4.21-4.16 (m, 1H), 2.93-2.88 (m, 4H), 2.67-2.60 (m, 4H), 2.13-2.10 (m, 2H). MS (ESI): m/z 494 [M+l]⁺. HPLC: 99.52%.

Effect on Neuronal Differentiation of Human Neural Stem Cells

[0130] Human neural stem cells (hNSCs) were assayed as monolayer cultures treated with varying concentrations of (lR,2R,3R,5R,6R)-6-((((adamantane-l- carbonyl)oxy)methoxy)carbonyl)-2-amino-3-((3,4-dichlorobenzyl)oxy)-6- fluorobicyclo[3.1.0]hexane-2-carboxylic acid (test compound), and stained with TUJ-1 antibody, as described in US Publication No. 20070015138. Mitogen- free test media with 3.16μΜ DHEA served as a positive control for neuronal differentiation, and basal media without growth factors served as a negative control.

[0131] Results are shown in Figure 1, which shows dose response curves of neuronal differentiation after background media values are subtracted. The data is presented as a percent of neuronal positive control. The data indicates that (lR,2R,3R,5R,6R)-6- ((((adamantane-l-carbonyl)oxy)methoxy)carbonyl)-2-amino-3-((3,4-dichlorobenzyl)oxy)-6- fluorobicyclo[3.1.0]hexane-2-carboxylic acid promoted neuronal differentiation.

Rut in Vivo Properties of Compounds 1, 3, 4 & 5

[0132] Compound 4, Compound 5 and Compound 1 were dosed at 10 mg/kg to fasted rats. The dosing solution comprised the Compound being tested, 20%> 2-hydroxypropyl-beta- cyclodextrin (ΗΡ-β-CD) /0.03NHC1 in water. Following dosing of the compounds they were absorbed and metabolized in vivo to deliver Compound 2. Plasma samples were drawn and analyzed for Compound 2 (active drug). The pharmacokinetic data for Compound 2 following 10 mg/kg administration in rat is provided in Figures 2, 3, 4, 11 and 12. This data is also provided in Table 1.

Table 1

Human In Vitro Properties of Compounds 1, 3, 4 & 5

Metabolic Stability in Human Microsomes (conducted by Absorption Systems, San Exton, PA,

USA)

[0133] Pooled human liver microsomes (mixed gender; microsomal protein concentration of 0.5 mg/mL) in buffer was incubated in a shaking water bath at 37°C for 5 minutes. The test compound (3μΜ) was added and the mixture vortexed for a few seconds and an aliquot removed (T=0 minute sample), quenched and precipitated in acetonitrile 0.5% formic acid solution containing an internal standard. To the remaining solution ImM NADPH was added and mixture incubated for 60 minutes. The mixture was then quenched and precipitated in acetonitrile 0.5% formic acid solution containing an internal standard. The supernatant from each sample (T = 0 and 60 minute) was then analyzed by LC-MS/MS for the amount of test compound and the amount of Compound 2. Calibration standards were prepared identically using heat-inactivated matrix. The experiment was run in duplicate

Metabolic Stability in Human Liver S9 (conducted by Absorption Systems, San Exton, PA, USA)

[0134] Pooled human liver S9 fractions in buffer was incubated in a shaking water bath at 37°C for 5 minutes. The test compound (3μΜ) was added and the mixture vortexed for a few seconds and an aliquot removed (T=0 minute sample), quenched and precipitated in

acetonitrile 0.5% formic acid solution containing an internal standard (testosterone and 7- hydroxycoumarin). To the remaining solution cofactors (ImM of mixed cofactors NADPH, UDPGA, PAPS and GSH) were added and mixture incubated for 60 minutes. The mixture was then quenched and precipitated in acetonitrile 0.5% formic acid solution containing an internal standard. The supernatant from each sample (T = 0 and 60 minute) was then

analyzed by LC-MS/MS for the amount of test compound and the amount of Compound 2. Calibration standards were prepared identically using heat-inactivated matrix. The experiment was run in duplicate.

Human Plasma Protein Binding (conducted by Absorption Systems, San Exton, PA, USA)

[0135] Human plasma protein (pooled from a minimum of 3 donors, mixed gender) containing sodium heparin was pH adjusted to 7.4 and the test compound added at ΙΟμΜ. The mixture was then subjected to equilibrium dialysis using a Teflon dual chamber microdialysis apparatus at 37°C for >22 hours. Warfarin was used as a positive control and the experiments were performed in duplicate. The supernatant from each compartment was then analyzed by LC-MS/MS for the amount of test compound, the amount of Compound 2 and warfarin. Calibration standards were prepared identically using matched matrix. The data is expressed as % protein bound.

Human Plasma Stability (conducted by Absorption Systems, San Exton, PA, USA)

[0136] Pooled human plasma was incubated at 37°C for 5 minutes then the test compound was added at 3μΜ, the mixture vortexed for a few seconds and an aliquot removed (T=0 minute sample), quenched and precipitated in acetonitrile 0.5% formic acid solution. The assay mixture was incubated for 60 minutes then quenched and precipitated in acetonitrile 0.5% formic acid solution. The supernatant from each sample (T = 0 and 60 minute) was then analyzed by LC-MS/MS for the amount of test compound and the amount of Compound 2. Calibration standards were prepared identically using heat-inactivated matrix. The experiment was run in duplicate.

Table 2

[0137] From these studies, it was determined that (1) Compound 4 has a higher free fraction in human plasma and improved human plasma conversion; (2) Compound 5 has an improved human liver and plasma conversion; and (3) Compound 1 has an improved human liver and plasma conversion when compared to Compound 3. Human In Vivo Pharmacokinetic Properties of Compounds 1, 3, 4 & 5

[0138] Compound 4, Compound 5 and Compound 1 were dosed at lmg to fasted subjects in an open label design (n = 6). Gelatin capsules containing the compounds were prepared within 24 hours of dosing to the subject. Each dose was separated by one week. Plasma samples were drawn and analyzed for Compound 2 (active drug) and subjects were monitored for safety and tolerability to 48 hours. Following dosing, all of the three novel compounds at lmg were found to be well tolerated by all subjects.

[0139] The pharmacokinetic data for Compound 2 following lmg of each of the three novel pro-drugs and the corresponding pro-drug data for Compound 3 following lmg is provided in Figures 8-10. This data is also provided in Table 3.

Table 3

[0140] The Tmax for Compound 2 following Compound 4, Compound 5 and Compound 1 occur at 3, 1.4 and 2.1 hrs, respectively. This is significantly faster than the Tmax of

Compound 2 following dosing of Compound 3, which occurs at 6 hrs. The Cmax is increased for Compound 2 following dosing with Compound 4 (Cmax is 4.4 ng/mL) and dosing with Compound 1 (Cmax is 8.1 ng/mL) compared to dosing with Compound 3 where the Cmax is 2.6 ng/mL.

[0141] The Cmax for Compound 2 is decreased after dosing with Compound 5 (Cmax is 1.8 ng/mL).

[0142] The AUC of Compound 2 is increased by approximately 21% for Compound 4 and 28% for Compound 1 compared to Compound 3. In contrast, the AUC of Compound 2 is decreased by 72% after dosing with Compound 5 as compared to Compound 3.

[0143] If the data is adjusted for differences in molecular weight (see Figures 5-7 and Table 4), the Cmax of Compound 2 obtained after dosing with Compound 1 increases by about 270%) and the AUC increases by 53% as compared to dosing with Compound 3. The same calculation shows that dosing of Compound 4 increases the Cmax by about 50% and the AUC by about 10%. Compound 5 shows reduced Cmax by about 30%> and AUC reduced by about 70%.

Table 4

[0144] For comparison, human clinical data from a Img i.v. and 15 and 45 mg oral crossover study with Compound 2 is provided in Table 5.

Table 5

[0145] Using the AUC obtained from the Img i.v. dose, the bioavailability of Compound 2 following Img of Compound 4, Compound 5 and Compound 1 is shown in Table 6. The bioavailability of Compound 1 is about 50% higher than Compound 4, the bioavailability Compound 4 is about the same as the bioavailability of Compound 3 and the bioavailability of Compound 5 is significantly reduced compared to the other three compounds.

Table 6

[0146] In summary, the human pharmacokinetic results (not dose-adjusted) of Compound 2 following dosing of Compound 1 and Compound 4 show that both of these pro-drugs are rapidly absorbed and converted to parent drug (Compound 2). There is an approximate 211% increase in Cmax of Compound 2 after Compound 1 dosing and 70% increase in Cmax of Compound 2 after Compound 4 dosing, when compared to that obtained following dosing of Compound 3. The increase in Cmax would be expected to result in higher initial brain concentrations and, as for rat, the brain drug concentration is expected to have a long half-life.

[0147] The human pharmacokinetic results (dose-adjusted) of Compound 2 following dosing of Compound 1 and Compound 4 show that both of these pro-drugs are rapidly absorbed and converted to parent drug (Compound 2). There is an approximate 270% increase in Cmax of Compound 2 after Compound 1 dosing and 50% increase in Cmax of Compound 2 after

Compound 4 dosing, when compared to that obtained following dosing of Compound 3. The increase in Cmax would be expected to result in higher initial brain concentrations and, as for rat, the brain drug concentration is expected to have a long half-life.

[0148] The results from these studies leads to the preliminary conclusion that (1) Compound 1 results in about a 311% higher Cmax of Compound 2 than obtained from Compound 3; (2) the AUC for Compound 2 is about 28% higher following dosing of Compound 1 than Compound 3; (3) the oral bioavailability of Compound 1 is improved versus Compound 3 and increases by about 50%; (4) Compound 4 results in about a 70% higher Cmax of Compound 2 than obtained from Compound 3; (5) the AUC for Compound 2 is about 21% higher following dosing of Compound 4 than Compound 3; and (6) Compound 1 and Compound 4 are absorbed and converted more rapidly than Compound 3.

Claims

WHAT IS CLAIMED IS:

1. A compound having the following structure or an analog thereof:

(Compound 1).

2. The compound of claim 1, wherein the Compound 1 is in a pharmaceutically acceptable salt or hydrate form.

A pharmaceutical composition comprising a prodrug of (lR,2R,3R,5R,6R)-2-amino-3-((3,4- dichlorobenzyl)oxy)-6-fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (Compound 2) with an oral bioavailabilty of at least about 35% when administered to a subject.

The pharmaceutical composition of Claim 3, wherein the oral bioavailability of the prodrug is between about 35% and about 50%>.

The pharmaceutical composition of Claim 3, further comprising one or more

pharmaceutically acceptable carriers, diluents, or excipients.

The pharmaceutical composition of claim 3, wherein the prodrug is

Compound 1), or a pharmaceutically acceptable salt or hydrate thereof.

7. A method for treating a disease, disorder or condition of the central and/or peripeheral

nervous system comprising administering a pharmaceutical composition comprising a prodrug of (lR,2R,3R,5R,6R)-2-amino-3-((3,4-dichlorobenzyl)oxy)-6- fluorobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (Compound 2) with an oral bioavailabilty between about 30% and about 50% when administered to a subject.

8. The method of claim 7, wherein the prodrug is

(Compound 1), or a pharmaceutically acceptable salt or hydrate thereof.

9. The method of claim 7, wherein the disease, disorder or condition is an mGluR 2 and/or an mGluR3 -dependent or mGluR 2 and/or mGluR3 -mediated disease or condition.

10. The method of claim 7, wherein the disease, disorder or condition is selected from the group consisting of Alzheimer's disease, schizophrenia, Parkinson's disease, anxiety, depression, treatment resistant depression, obsessive compulsive disorders, psychosis, addiction, epilepsy, insomnia, brain or central nervous system trauma and/or recover there from, ischemia of the central and/or peripheral nervous systems, pain, learning and memory disorders and cognitive and memory deficiencies due to disease or aging.

11. The method of claim 7, wherein the disease, disorder or condition is a nervous system

disorder related to cellular degeneration, a psychiatric condition, cognitive impairment, cellular trauma or injury, or another neurologically related condition.

12. The method of claim 11, wherein the cellular degeneration disease is selected from the group consisting of a neurodegenerative disorder, a neural stem cell disorder, a neural progenitor cell disorder, an ischemic disorder or a combination thereof.

13. The method of claim 12, wherein the neurodegenerative disorder is a degenerative disease of the retina, lissencephaly syndrome, or cerebral palsy.

14. The method of claim 11, wherein the psychiatric condition is a neuropsychiatric disorder.