WO2018073753A1

WO2018073753A1 - Fused tetracyclic pyridone compounds as antivirals

Info

Publication number: WO2018073753A1
Application number: PCT/IB2017/056457
Authority: WO
Inventors: Jiping Fu; Subramanian Karur; Keith Bruce PFISTER
Original assignee: Novartis Ag
Priority date: 2016-10-18
Filing date: 2017-10-18
Publication date: 2018-04-26
Also published as: TW201819380A

Abstract

The invention provides compounds of Formula (I) as described herein, along with pharmaceutically acceptable salts, pharmaceutical compositions containing such compounds, and methods to use these compounds, salts and compositions for treating viral infections, particularly infections caused by hepatitis B virus, and reducing the occurrence of serious conditions associated with HBV.

Description

FUSED TETRACYCLIC PYRIDONE COMPOUNDS AS ANTIVIRALS

CROSS-REFERENCE TO RELATED APPLICATION

[001] This application claims priority to US provisional application Serial

No. 62/409,813, filed 18 October 2016, the contents of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[002] The present invention relates to novel fused tetracyclic pyridone compounds that are inhibitors of hepatitis virus replication, and are thus useful to treat viral infections, and particularly hepatitis B virus (HBV). The invention provides novel tetracyclic pyridone compounds as disclosed herein, pharmaceutical compositions containing such compounds, and methods of using these compounds and compositions in the treatment and prevention of HBV infections.

BACKGROUND

[003] Globally, over 400 million people are chronically infected with hepatitis B virus

(HBV), and more than 12 million reside in the United States alone. Of those chronically infected patients, up to 40 percent will eventually develop complications of liver failure from cirrhosis or development of hepatocellular carcinoma (HCC). HBV belongs to the family of

Hepadnaviridae, a group of small hepatotropic DNA viruses that replicate through the reverse transcription of an RNA intermediate. The 3.2-kb HBV genome in viral particles is in a circular, partially double-stranded DNA conformation (relaxed circular DNA or rcDNA). The HBV genome consists of four overlapping open reading frames (ORFs), which encode for the core, polymerase (Pol), envelope, and X proteins. rcDNA is transcriptionally inert and must be converted into covalently closed circular DNA (cccDNA) in the nucleus of infected cells before viral RNAs can be transcribed. cccDNA is the only template for HBV transcription and, because HBV RNA templates genomic reverse transcription, its persistence is required for persistent infection.

[004] The envelope of HBV comprises a mixture of surface antigen proteins (HBsAg).

The HBsAg coat is a mixture of three overlapping proteins: all three share a common region, which corresponds to the smallest of the three proteins (SHBsAg). The mixture consists mostly of SHBsAg, but also includes Medium HBsAg, which comprises SHBsAg plus an additional polypeptide segment, and Large HBsAg, which comprises M HBsAg plus another added polypeptide segment. In addition to forming the infectious virion particle, the S, M and L HBsAg proteins also assemble into a subvirai particle knows as the 22-nm particle, which is not infectious but contains the same proteins that envelope the infectious virus particles. Indeed, these subvirai, non-infectious particles have been used as a vaccine, since they contain the same antigenic surface proteins as the infectious HBV virion, and thus elicit antibodies that recognize the infectious agent. Interestingly, these subvirai particles greatly outnumber infectious virions, and are believed to protect the infectious virions from the immune system of the infected host. By sheer numbers, they may act as decoys, distracting immune responses from the infectious virus particles, but in addition they are reported to suppress the function of immune ceils (monocytes, dendritic cells and natural killer cells) and may thus impair the immune response to HBV. Because these subvirai particles protect infectious HBV from the host immune system, reducing the level of subvirai particles has been recognized as a viable therapeutic approach. See, e.g., WO2015/1 13990.

[005] One of the key diagnostic symptoms of chronic HBV is the high serum levels of the hepatitis B surface antigen (HBsAg). Clinical data in recent years suggest that sustained virologic response is often associated with on-treatment HBsAg decline during the early phase of the treatment as early as week 8, while sustained exposure to HBsAg and other viral antigens may lead to HBV-specific immune-tolerance. Chronic HB patients who experienced larger and faster decreases in serum HBsAg levels achieved significantly higher rate (-40%) of sustained virologic response as defined by sustained viral control post treatment.

[006] Current treatment options for HBV include interferon therapies and

nucleoside/nucleotide inhibitors of the viral DNA polymerase, such as entecavir and tenofovir. These focus on reduction in the level of viremia and toleration of hepatic dysfunction, and may have adverse side-effects and also select for drug-resistant virus variants during long term therapy. More importantly, these therapies cannot eradicate the intrahepatic HBV cccDNA pool in chronic hepatitis B patients or limit the transcription of HBsAg from the pre-existing cccDNA, nor do they affect the secretion of synthesized HBsAg into patients' blood to counteract the host innate immune response. As a result, these HBV treatments are in most cases life-long therapies, and discontinuation often leads to virological relapse.

[007] Accordingly, there remains a need for more effective treatments for HBV, especially for treating chronic HBV infections (cHBV). The invention provides compounds that are believed to operate by suppression of the secretion of the 22 nm subvirai particles containing HBsAg. These compounds are useful to treat HBV infections and to reduce the incidence of serious liver disorders caused by HBV infections. SUMMARY

[008] The present invention provides novel compounds that inhibit secretion of HBsAg from ceils infected with hepatitis B virus and thereby reduce viral load and viral replication in patients having chronic HBV infection. Thus the compounds of the invention are suitable for treatment of patients with HBV, including chronic HBV.

[009] In one aspect, the invention provides compounds of Formula (I):

(I) wherein:

R¹ is H, halo, C C₃ alkyl or d-C₃ haloalkyl;

R² is H, halo, CN, C1-C3 alkyl, C1-C3 haloalkyl, -OR, or -C(0)NR₂;

W is -COOR³, -C(0)NH-S0₂R, -C(0)NH-S0₂NR₂, 5-tetrazolyl, or 1 ,2,4-oxadiazol-3-yl-5(4H)- one;

R³ is H or Ci-C₆ alkyl that is optionally substituted with one to three groups selected from halo, -OR, oxo, CN, and -NR₂;

Z¹ is N or CR^z1 ;

Z² is N or CR^Z2;

Z³ is N or CR^Z3;

Z⁴ is N or CR^Z4;

provided not more than one of Z¹ , Z², Z³ and Z⁴ is N;

R^Z1 is H, OH, halo, CN, C C₃ alkyl optionally substituted with up to three groups selected from oxo, halo, -CN, R, -OR, -NR₂, and -C(0)NR₂, or Ci-C₃ alkoxy optionally substituted with up to three groups selected from halo, oxo, CN, R, -OR, -NR₂, and -C(0)NR₂;

R^Z2 is selected from H, halo, R⁴, -OR⁴, -SR⁴, and -NRR⁴;

R⁴ is C C₄ alkyl, C₃-C₆ cycloalkyi, oxetanyl, tetrahydrofuranyl, or tetrahydropyranyl, each of which is optionally substituted with up to three groups selected from halo, CN, -OR, C_r C₃ haloalkoxy, -CONR₂, C₃-C₆ cycloalkyi, and a 4-7 membered heterocyclic group containing one or two heteroatoms selected from N, O and S as ring members, wherein the C₃-C₆ cycloalkyi and 4-7 membered heterocyclic group are each optionally substituted with one or two groups selected from halo, oxo, CN, R, -OR, and -NR₂; R is independently selected at each occurrence from H and d-C₃ alkyl optionally substituted with one to three groups selected from halo, -OH, C d alkoxy, oxo, CN, -NH₂, - NH(Ci-C₃ alkyl) , -N(C₁-C₃ alkyl)₂, and cyclopropyl;

and two R groups directly attached to the same atom can optionally be taken together to form a 3-6 membered ring that can optionally contain a heteroatom selected from N, O and S as a ring member, and can be substituted by up to two groups selected from -OH, oxo, C₁-C3 alkyl, and C₁-C3 alkoxy;

R^Z3 is H, OH, halo, CN, C₁ -C3 alkyl, C₃-C₆ cycloalkyi, C₁ -C3 haloalkyl, or -OR;

R^Z4 is H, OH, halo, CN, Me, OMe, or CF₃;

R⁶ is H, halo, C C₃ alkoxy, or C C₆ alkyl, or is taken together with R⁹ to form a ring as described below;

R⁷ is H, halo, Ci-C₃ alkoxy, or d-C₆ alkyl, or is taken together with R⁹ to form a ring as described below;

R⁸ is H or Ci-C₆ alkyl;

R⁹ is H, C C₆ alkyl optionally substituted with up to three groups selected from C₃-C₆ cycloalkyi, -OR, -NR₂, halo, CN, COOR, CONR₂, and oxo,

or R⁹ can be a ring selected from C₃-C₆ cycloalkyi, phenyl, 5-6 membered heterocyclyl containing one or two heteroatoms selected from N, O and S as ring members, and 5-6 membered heteroaryl containing one or two heteroatoms selected from N, O and S as ring members, wherein each of these rings is optionally substituted with up to three groups selected from C₁-C₂ alkyl, -OR, -NR₂, halo, CN, COOR, CONR₂, and oxo;

or R⁹ taken together with either R⁶ or R⁷ forms a 3-7 membered cycloalkyi ring or a 3-7 membered heterocyclic ring containing N, O or S as a ring member; wherein the cycloalkyi or heterocyclic ring is optionally substituted with up to three groups selected from R, -OR, -NR₂, halo, CN, COOR, CONR₂, and oxo;

or a pharmaceutically acceptable salt thereof.

[0010] The invention also includes pharmaceutical compositions containing these compounds, methods to use these compounds and compositions to treat viral infections, pharmaceutical combinations comprising these compounds, and methods to use the compounds in the manufacture of a medicament.

DETAILED DESCRIPTION

[0011] For purposes of interpreting this specification, the following definitions will apply, and whenever appropriate, terms used in the singular will also include the plural. [0012] Terms used in the specification have the following meanings unless the context clearly indicates otherwise:

[0013] As used herein, the term "subject" refers to an animal. In certain aspects, the animal is a mammal. A subject also refers to for example, primates (e.g., humans), cows, sheep, goats, horses, dogs, cats, rabbits, rats, mice, fish, birds and the like. In certain embodiments, the subject is a human. A "patient" as used herein refers to a human subject.

[0014] As used herein, the term "inhibition" or "inhibiting" refers to the reduction or suppression of a given condition, symptom, or disorder, or disease, or a significant decrease in the baseline activity of a biological activity or process.

[0015] As used herein, the term "treating" or "treatment" of any disease or disorder refers in one embodiment, to ameliorating the disease or disorder (i.e., slowing or arresting or reducing the development of the disease or at least one of the clinical symptoms thereof). In another embodiment "treating" or "treatment" refers to alleviating or ameliorating at least one physical parameter including those which may not be discernible by the patient. In yet another embodiment, "treating" or "treatment" refers to modulating the disease or disorder, either physically, (e.g., stabilization of a discernible symptom), physiologically, (e.g., stabilization of a physical parameter), or both. In yet another embodiment, "treating" or "treatment" refers to preventing or delaying the onset or development or progression of the disease or disorder.

[0016] As used herein, the term "a," "an," "the" and similar terms used in the context of the present invention (especially in the context of the claims) are to be construed to cover both the singular and plural unless otherwise indicated herein or clearly contradicted by the context.

[0017] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed.

[0018] "Optionally substituted" means the group referred to can be substituted at one or more positions by any one or any combination of the radicals listed thereafter. The number, placement and selection of substituents is understood to encompass only those substitutions that a skilled chemist would expect to be reasonably stable; thus Όχο' would not be a substituent on an aryl or heteroaryl ring, for example, and a single carbon atom would not have three hydroxy or amino substituents. Unless otherwise specified, optional substituents are typically up to four groups selected from halo, oxo, CN, amino, hydroxy, -C_h alky!, -OR*, - NRVSR*, -S0₂R*, -COOR*, and -CONR*₂, where each R* is independently H or d-₃ alkyl. [0019] "Aryl" as used herein refers to a phenyl or naphthyl group unless otherwise specified. Aryl groups unless otherwise specified may be optionally substituted with up to four groups selected from halo, CN, amino, hydroxy, d-₃ alkyl, -OR^*, -NR^* ₂,-SR^*, -S0₂R^*, -COOR^*, and -CONR*2, where each R^* is independently H or Ci_₃ alkyl.

[0020] "Halo" or "halogen", as used herein, may be fluorine, chlorine, bromine or iodine.

[0021] "d-6 alkyl" or "CrC₆ alkyl", as used herein, denotes straight chain or branched alkyl having 1 -6 carbon atoms. If a different number of carbon atoms is specified, such as C₄ or C₃, then the definition is to be amended accordingly, such as "Ci_-4 alkyl" will represent methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl.

[0022] "Ci-₆ alkylene" or "d-C₆ alkylene", as used herein, denotes straight chain or branched alkyl having 1 -6 carbon atoms and two open valences for connection to two other groups. If a different number of carbon atoms is specified, such as C₄ or C₃, then the definition is to be amended accordingly, such as "Ci_-4 alkylene" will represent methylene (-CH₂-), ethylene (-CH₂CH₂-), straight chain or branched propylene (-CH₂CH₂CH₂- or -CH₂-CHMe-CH₂- ), and the like.

[0023] "C^ alkoxy", as used herein, denotes straight chain or branched alkoxy (-0-

Alkyl) having 1 -6 carbon atoms. If a different number of carbon atoms is specified, such as C₄ or C₃, then the definition is to be amended accordingly, such as "Ci_-4 alkoxy" will represent methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy and tert-butoxy.

[0024] "C_1-4 Haloalkyl" or "C C₄ haloalkyl" as used herein, denotes straight chain or branched alkyl having 1 -4 carbon atoms wherein at least one hydrogen has been replaced with a halogen. The number of halogen replacements can be from one up to the number of hydrogen atoms on the unsubstituted alkyl group. If a different number of carbon atoms is specified, such as C₆ or C₃, then the definition is to be amended accordingly. Thus "Ci_-4 haloalkyl" will represent methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl that have at least one hydrogen substituted with halogen, such as where the halogen is fluorine: CF₃CF₂-, (CF₃)₂CH-, CH₃-CF₂-, CF₃CF₂-, CF₃, CF₂H-, CF₃CF₂CH(CF₃)- or

CF₃CF₂CF₂CF₂-.

[0025] "C₃.₈ cycloalkyl" as used herein refers to a saturated monocyclic hydrocarbon ring of 3 to 8 carbon atoms. Examples of such groups include cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. If a different number of carbon atoms is specified, such as C₃-C₆, then the definition is to be amended accordingly.

[0026] "4- to 8-Membered heterocyclyl", "5- to 6- membered heterocyclyl", "3- to 10- membered heterocyclyl", "3- to 14-membered heterocyclyl", "4- to 14-membered heterocyclyl" and "5- to 14-membered heterocyclyl", refers, respectively, to 4- to 8-membered, 5- to 6- membered, 3- to 10-membered, 3- to 14-membered, 4- to 14-membered and 5- to

14-membered heterocyclic rings; unless otherwise specified, such rings contain 1 to 7, 1 to 5, or 1 to 3 heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur as ring members, and the rings may be saturated, or partially saturated but not aromatic. The heterocyclic group can be attached to another group at a nitrogen or a carbon atom. The term "heterocyclyl" includes single ring groups, fused ring groups and bridged groups. Examples of such heterocyclyl include, but are not limited to pyrrolidine, piperidine, piperazine,

pyrrolidinone, morpholine, tetrahydrofuran, tetrahydrothiophene, tetrahydrothiopyran, tetrahydropyran, 1 ,4-dioxane, 1 ,4-oxathiane, 8-aza-bicyclo[3.2.1 ]octane, 3,8- diazabicyclo[3.2.1 ]octane, 3-Oxa-8-aza-bicyclo[3.2.1 ]octane, 8-Oxa-3-aza-bicyclo[3.2.1 ]octane, 2-Oxa-5-aza-bicyclo[2.2.1 ]heptane, 2,5-Diaza-bicyclo[2.2.1 ]heptane, azetidine, ethylenedioxo, oxetane or thiazole. In certain embodiments, if not otherwise specified, heterocyclic groups have 1 -2 heteroatoms selected from N, O and S as ring members, and 4-7 ring atoms, and are optionally substituted with up to four groups selected from halo, oxo, CN, amino, hydroxy, alkyl, -OR^*, -NR^* ₂,-SR^*, -S0₂R^*, -COOR^*, and -CONR^* ₂, where each R^* is independently H or C_1-3 alkyl. In particular, heterocyclic groups containing a sulfur atom are optionally substituted with one or two oxo groups on the sulfur.

[0027] "Heteroaryl" is a completely unsaturated (aromatic) ring. The term "heteroaryl" refers to a 5-14 membered monocyclic- or bicyclic- or tricyclic-aromatic ring system, having 1 to 8 heteroatoms selected from N, O or S. Typically, the heteroaryl is a 5-10 membered ring or ring system (e.g., 5-7 membered monocyclic group or an 8-10 membered bicyclic group), often a 5-6 membered ring containing up to four heteroatoms selected from N, O and S, though often a heteroaryl ring contains no more than one divalent O or S in the ring. Typical heteroaryl groups include furan, isothiazole, thiadiazole, oxadiazole, indazole, indole, quinoline, 2- or 3- thienyl, 2- or 3-furyl, 2- or 3-pyrrolyl, 2-, 4-, or 5-imidazolyl, 3-, 4-, or 5- pyrazolyl, 2-, 4-, or 5- thiazolyl, 3-, 4-, or 5-isothiazolyl, 2-, 4-, or 5-oxazolyl, 3-, 4-, or 5-isoxazolyl, 3- or 5-(1 ,2,4- triazolyl), 4- or 5-(1 ,2, 3-triazolyl), tetrazolyl, triazine, pyrimidine, 2-, 3-, or 4-pyridyl, 3- or 4- pyridazinyl, 3-, 4-, or 5-pyrazinyl, 2-pyrazinyl, and 2-, 4-, or 5-pyrimidinyl. Heteroaryl groups are optionally substituted with up to four groups selected from halo, CN, amino, hydroxy, Ci_₃ alkyl, -OR^*, -NR^* ₂,-SR^*, -S0₂R^*, -COOR^*, and -CONR^* ₂, where each R^* is independently H or Ci-3 alkyl.

[0028] The term "hydroxy" or "hydroxyl" refers to the group -OH.

[0029] Various embodiments of the invention are described herein. It will be recognized that features specified in each embodiment may be combined with other specified features to provide further embodiments. [0030] The following enumerated embodiments are representative of the invention:

[0031] 1 . A compound of formula (I):

(I) wherein:

R¹ is H, halo, C C₃ alkyl or d-C₃ haloalkyl;

R² is H, halo, CN, C_rC₃ alkyl, C C₃ haloalkyl, -OR, or -C(0)NR₂;

W is -COOR³, -C(0)NH-S0₂R, -C(0)NH-S0₂NR₂, 5-tetrazolyl, or 1 ,2,4- oxadiazol-3-yl-5(4H)-one;

Z¹ is N or CR^z1 ;

Z² is N or CR^Z2;

Z³ is N or CR^Z3;

Z⁴ is N or CR^Z4;

provided not more than one of Z¹ , Z², Z³ and Z⁴ is N;

R^Z1 is H, OH, halo, CN, C₁ -C3 alkyl optionally substituted with up to three groups selected from oxo, halo, -CN, R, -OR, -NR₂, and -C(0)NR₂, or Ci-C₃ alkoxy optionally substituted with up to three groups selected from halo, oxo, CN, R, -OR, -NR₂, and -C(0)NR₂;

R^Z2 is selected from H, halo, R⁴, -OR⁴, -SR⁴, and -NRR⁴;

R⁴ is C₁-C4 alkyl, C₃-C₆ cycloalkyi, oxetanyl, tetrahydrofuranyl, or tetrahydropyranyl, each of which is optionally substituted with up to three groups selected from halo, CN, -OR, Ci-C₃ haloalkoxy, -CONR₂, C₃-C₆ cycloalkyi, and a 4-7 membered heterocyclic group containing one or two heteroatoms selected from N, O and S as ring members, wherein the C₃-C₆ cycloalkyi and 4-7 membered heterocyclic group are each optionally substituted with one or two groups selected from halo, oxo, CN, R, -OR, and -NR₂;

R is independently selected at each occurrence from H and C C₃ alkyl optionally substituted with one to three groups selected from halo, -OH, Ci-C₃ alkoxy, oxo, CN, -NH₂, -NH(Ci-C₃ alkyl), -N(Ci-C₃ alkyl)₂, and cyclopropyl;

and two R groups directly attached to the same atom can optionally be taken together to form a 3-6 membered ring that can optionally contain a heteroatom selected from N, O and S as a ring member, and can be substituted by up to two groups selected from -OH, oxo, C C₃ alkyl, and C1 -C3 alkoxy;

R^Z3 is H, OH, halo, CN, C C₃ alkyl, C₃-C₆ cycloalkyi, Ci-C₃ haloalkyl, or -OR;

R^Z4 is H, OH, halo, CN, Me, OMe, or CF₃;

R⁶ is H, halo, C1 -C3 alkoxy, or d-C₆ alkyl, or is taken together with R⁹ to form a ring as described below;

R⁷ is H, halo, C1 -C3 alkoxy, or d-C₆ alkyl, or is taken together with R⁹ to form a ring as described below;

R⁸ is H or Ci-C₆ alkyl;

or R⁹ can be a ring selected from C₃-C₆ cycloalkyi, phenyl, 5-6 membered heterocyclyl containing one or two heteroatoms selected from N, O and S as ring members, and 5-6 membered heteroaryl containing one or two heteroatoms selected from N, O and S as ring members, wherein each of these rings is optionally substituted with up to three groups selected from d-C₂ alkyl, -OR, -NR₂, halo, CN, COOR, CONR₂, and oxo;

or R⁹ taken together with either R⁶ or R⁷ forms a 3-7 membered cycloalkyi ring or a 3-7 membered heterocyclic ring containing N, O or S as a ring member; wherein the cycloalkyi or heterocyclic ring is optionally substituted with up to three groups selected from R, - OR, -NR₂, halo, CN, COOR, CONR₂, and oxo;

or a pharmaceutically acceptable salt thereof.

[0032] 2. The compound of embodiment 1 , or a pharmaceutically acceptable salt thereof, wherein R¹ is H or F.

[0033] 3. The compound according to any one of the preceding embodiments, or a pharmaceutically acceptable salt thereof, wherein R² is H, Me, CN, halo, or OMe. In some of these embodiments, R² is H or F.

[0034] 4. A compound according to any one of embodiments 1 to 3, wherein W is

-COOR³; or a pharmaceutically acceptable salt thereof. In some such embodiments, R³ is H, methyl or ethyl.

[0035] 5. The compound of any of embodiments 1 -4, wherein R⁶ is H and R⁷ is H; or a pharmaceutically acceptable salt thereof.

[0036] 6. The compound of any of embodiments 1 -5, wherein R⁹ is Ci-C₆ alkyl optionally substituted with up to three groups selected from C₃-C₆ cycloalkyi, -OR, -NR₂, halo, CN, COOR, CONR₂, and oxo; or a pharmaceutically acceptable salt thereof. In some of these embodiments, R⁸ is H. [0037] 7. The compound of any of embodiments 1 -4, wherein R⁹ taken together with either R⁶ or R⁷ forms a 3-7 membered cycloalkyi ring or a 3-7 membered heterocyclic ring containing N, O or S as a ring member; wherein the cycloalkyi or heterocyclic ring is optionally substituted with up to three groups selected from R, -OR, -NR₂, halo, CN, COOR, CONR₂, and oxo; or a pharmaceutically acceptable salt thereof. In these embodiments, R⁸ is typically H, and the group R⁶ or R⁷ that does not form a ring with R9 is often also H.

[0038] 8. The compound of any of embodiments 1 -7, wherein:

Z¹ is CR^Z1 ;

Z² is CR^Z2;

Z³ is CR^Z3; and

Z⁴ is CR^Z4;

or a pharmaceutically acceptable salt thereof.

[0039] 9. The compound of any one of embodiments 1 -7, wherein one of Z¹ , Z², Z³ and Z⁴ is N; or a pharmaceutically acceptable salt thereof.

[0040] 10. The compound of any of embodiments 1 -7, which is of the formula:

Z² is CR^Z2;

Z³ is CR^Z3; and

Z⁴ is CR^Z4;

and R³ is H or d-C₄ alkyl;

or a pharmaceutically acceptable salt thereof. [0041] 1 1 . A compound according to any of embodiments 1 -5, wherein R⁹ is isopropyl, t-butyl, cyclopropyl, cyclobutyl, phenyl, or thiophene, and is optionally substituted with up to three groups selected from C1 -C2 alkyl, -OR, -NR₂, halo, CN, COOR, and CONR₂; or a pharmaceutically acceptable salt thereof.

[0042] 12. A compound according to any of embodiments 1 -1 1 , wherein R⁸ is H; or a pharmaceutically acceptable salt thereof.

[0043] 13. A compound according to any one of embodiments 1 -1 1 , wherein R^Z1 is

H, halo, C1-2 haloalkyl, or -OR; or a pharmaceutically acceptable salt thereof. In some of these embodiments, R^Z1 is methoxy, trifluoromethoxy, difluoromethoxy or fluoromethoxy.

[0044] 14. The compound of any one of embodiments 1 -12, wherein R^Z2 is selected from H, halo, C_1-2 haloalkyl, -OMe, and -OR; or a pharmaceutically acceptable salt thereof. In some of these embodiments, R^Z2 is H, methoxy, trifluoromethoxy, difluoromethoxy or fluoromethoxy.

[0045] 15. The compound of any one of embodiments 1 -12, wherein R^Z3 is selected from H, halo, C_1-2 haloalkyl, and -OR; or a pharmaceutically acceptable salt thereof. In some of these embodiments, R^Z3 is H.

[0046] 16. The compound of any one of embodiments 1 -12, wherein R^Z4 is H or halo; or a pharmaceutically acceptable salt thereof. In some of these embodiments, R^Z4 is H.

[0047] 17. The compound of embodiment 1 , which is selected from the compounds of the Examples in Table 1 .

[0048] 18. A pharmaceutical composition, comprising a compound of any of the preceding embodiments admixed with at least one pharmaceutically acceptable carrier.

[0049] 19. A method to treat a subject having a hepatitis B infection, which comprises administering to the subject a compound of any of embodiments 1 -17 or a pharmaceutical composition of embodiment 18.

[0050] 20. The method of embodiment 19, wherein the compound of any one of claims 1 -17 or the pharmaceutical composition of embodiment 18 is used in combination with an additional therapeutic agent selected from an interferon or peginterferon, an HBV polymerase inhibitor, a viral entry inhibitor, a viral maturation inhibitor, a capsid assembly inhibitor, an HBV core modulator, a reverse transcriptase inhibitor, a TLR-agonist, or an immunomodulator.

[0051] 21 . A method to inhibit replication of hepatitis B virus, which comprises contacting the hepatitis B virus, either in vitro or in vivo, with a compound according to any one of embodiments 1 -17. [0052] 22. A pharmaceutical combination, comprising a compound of any of embodiments 1 -17 and at least one additional therapeutic agent.

[0053] 23. A compound according to any of embodiments 1 -17 for use in therapy.

[0054] 24. The compound according to embodiment 23 wherein the therapy is treatment of a bacterial infection.

[0055] 25. Use of a compound according to any one of embodiments 1 -17 in the manufacture of a medicament.

[0056] Another embodiment of the invention provides a compound as described above, or a pharmaceutically acceptable salt thereof, for use as a medicament. In one aspect, the medicament is for treatment of a subject having an HBV infection. In a particular embodiment, the subject is a human diagnosed with chronic HBV.

[0057] Also within the scope of this invention is the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament; in some embodiments, this medicament is for the treatment or prevention of a viral disease and/or infection in a human being, particularly where the virus involved is HBV.

[0058] Included within the scope of this invention is a pharmaceutical composition comprising a compound of Formula (I), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or excipient. Optionally, the composition comprises at least two pharmaceutically acceptable carriers and/or excipients.

[0059] According to a further aspect of this embodiment the pharmaceutical composition according to this invention further comprises a therapeutically effective amount of at least one other antiviral agent.

[0060] The invention also provides the use of a pharmaceutical composition as described hereinabove for the treatment of a HBV infection in a human being having or at risk of having the infection.

[0061] The invention also provides the use of a pharmaceutical composition as described hereinabove for the treatment of HBV infection in a human being having or at risk of having the disease.

[0062] Another aspect of the invention involves a method of treating or preventing a hepatitis B viral disease and/or infection in a human being by administering to the human being an antivirally effective amount of a compound of the invention, a pharmaceutically acceptable salt thereof, or a composition as described above, alone or in combination with at least one other antiviral agent, administered together or separately.

[0063] An additional aspect of this invention refers to an article of manufacture comprising a composition of the invention that is effective to treat a hepatitis B viral disease and/or infection; and packaging material comprising a label which indicates that the

composition can be used to treat disease and/or infection by a hepatitis B virus; wherein the composition comprises a compound of formula (I) according to this invention or a

pharmaceutically acceptable salt thereof.

[0064] Still another aspect of this invention relates to a method of inhibiting the replication of HBV, comprising exposing the virus to an effective amount of the compound of formula (I), or a salt thereof, under conditions where replication of the virus is inhibited. This method can be practiced in vitro or in vivo.

[0065] Further included in the scope of the invention is the use of a compound of formula (I), or a salt thereof, to inhibit the replication of HBV.

[0066] In all of the embodiment referring to a compound of Formula (I), the compound of Formula (I) can be a compound according to any of embodiments 1 -17 described above.

[0067] In some embodiments, the compound of Formula (I) is co-administered with or used in combination with at least one additional therapeutic agent selected from: an interferon or peginterferon, an HBV polymerase inhibitor, a viral entry inhibitor, a viral maturation inhibitor, a capsid assembly inhibitor, an HBV core modulator, a reverse transcriptase inhibitor, a TLR- agonist, or an immunomodulator. Optionally, the compound of Formula (I) may be prepared for simultaneous or sequential use in combination with an additional therapeutic agent; or the compound of Formula (I) may be combined into a pharmaceutical combination comprising a compound of Formula (I) and at least one additional therapeutic agent. Some particular therapeutic agents that may be used in combination with the compounds of the invention include immunomodulators described herein, interferon alfa 2a, interferon alfa-2b, pegylated interferon alfa-2a, pegylated interferon alfa-2b, TLR-7 and TLR-9 agonists, entecavir, tenofovir, cidofovir, telbivudine, didanosine, zalcitabine, stavudine, lamivudine, abacavir, emtricitabine, apricitabine, atevirapine, ribavirin, acyclovir, famciclovir, valacyclovir, ganciclovir, adefovir, efavirenz, nevirapine, delavirdine, and etravirine. Suitable core modulators are disclosed in WO2013/096744; suitable HBV capsid inhibitors are described in US2015/0252057.

[0068] These additional agents may be combined with the compounds of this invention to create a single pharmaceutical dosage form. Alternatively these additional agents may be separately administered to the patient as part of a multiple dosage form, for example, using a kit. Such additional agents may be administered to the patient prior to, concurrently with, or following the administration of a compound of the invention, or a pharmaceutically acceptable salt thereof. Alternatively, these additional therapeutic agents may be administered separately from and optionally by different routes of administration and on different dosing schedules from the compound of the invention, provided the compound of the invention and the additional therapeutic agent are used concurrently for treatment of an HBV infection or a disorder caused or complicated by an HBV infection.

[0069] The dose range of the compounds of the invention applicable per day is usually from 0.01 to 100 mg/kg of body weight, preferably from 0.1 to 50 mg/kg of body weight. Each dosage unit may conveniently contain from 5% to 95% active compound (w/w). Preferably such preparations contain from 20% to 80% active compound.

[0070] The actual pharmaceutically effective amount or therapeutic dosage will of course depend on factors known by those skilled in the art such as age and weight of the patient, route of administration and severity of disease. In any case the combination will be administered at dosages and in a manner which allows a pharmaceutically effective amount to be delivered based upon patient's unique condition.

[0071] When the composition of this invention comprises a combination of a compound of the invention and one or more additional therapeutic or prophylactic agent, both the compound and the additional agent should be present at dosage levels of between about 10 to 100%, and more preferably between about 10 and 80% of the dosage normally administered in a monotherapy regimen.

[0072] Antiviral agents contemplated for use in such combination therapy include agents (compounds or biologicals) that are effective to inhibit the formation and/or replication of a virus in a human being, including but not limited to agents that interfere with either host or viral mechanisms necessary for the formation and/or replication of a virus in a human being. Such agents can be selected from entecavir, tenofovir, cidofovir, telbivudine, didanosine, zalcitabine, stavudine, lamivudine, abacavir, emtricitabine, apricitabine, atevirapine, ribavirin, acyclovir, famciclovir, valacyclovir, ganciclovir, adefovir, efavirenz, nevirapine, delavirdine, and etravirine, and immunomodulators described herein including interferons and pegylated interferons, TLR-7 agonists, and TLR-9 agonists.

[0073] Many compounds of the invention contain one or more chiral centers. These compounds may be made and used as single isomers or as mixtures of isomers. Methods for separating the isomers, including diastereomers and enantiomers, are known in the art, and examples of suitable methods are described herein. In certain embodiments, the compounds of the invention are used as a single substantially pure isomer, meaning at least 90% of a sample of the compound is the specified isomer and less than 10% of the sample is any other isomer or mixture of isomers. Preferably, at least 95% of the sample is a single isomer.

Selection of a suitable isomer is within the ordinary level of skill, as one isomer will typically be more active in the in vivo or in vitro assay described herein for measuring HBV activity, and will be the preferred isomer. Where in vitro activity differences between isomers are relatively small, e.g. less than about a factor of 4, a preferred isomer may be selected based on activity level against viral replication in cell culture, using methods such as those described herein: the isomer having a lower MIC (minimum inhibitory concentration) or EC-50 is preferred.

[0074] The compounds of the invention may be synthesized by the general synthetic routes illustrated below, specific examples of which are described in more detail in the

Examples. Additional guidance for synthesis of the compounds of Formula (I) and synthetic intermediates useful for these syntheses are disclosed in published PCT applications

WO2015/1 13990 and WO2015/173164.

[0075] Scheme 1 illustrates a general method useful to make compounds of the invention, as demonstrated in the Examples herein. A variety of indole-2-carboxylates and azaindole-2-carboylate starting materials are known in the art. The carboxylate can be reduced to an alcohol using methods known in the art, and the alcohol can be protected with a protecting group such as known silyl ethers (e.g., TBS), the indole nitrogen can be alkylated with a suitable alph-haloketone to introduce the group containing R⁹. Reductive amination is one method to introduce nitrogen at the carbonyl center. Once the primary amine is in place, the protected alcohol at C2 of the indole/azaindole can be deprotected and oxidized to an aldehyde oxidation state, at which point it cyclizes with the primary amine to form the new 6- membered ring substituted with R⁹.

[0076] The imine of the new ring is then annulated to form an additional fused ring by a method known in the art, using (Z)-ethyl 2-(ethoxymethylene)-3-oxobutanoate. The new ring is then oxidized to provide the pyridone ring shown in Formula (I). Methods useful in preparing these compounds are disclosed in published PCT applications WO2015/1 13990 and

WO2015/173164.

Scheme 1. General method to synthesize compounds of Formula (I).

[0077] Using this general method, other known starting materials, and the examples herein, a person of ordinary skill can synthesize compounds of Formula (I). Enantiomers of these compounds can be separated by chiral HPLC and similar known methods. While one enantiomer of compounds of this formula is typically more active than the other enantiomer, both isomers exhibit activity one HBsAg as demonstrated herein.

[0078] The term "an optical isomer" or "a stereoisomer" refers to any of the various stereoisomeric configurations which may exist for a given compound of the present invention and includes geometric isomers. It is understood that a substituent may be attached at a chiral center of a carbon atom. The term "chiral" refers to molecules which have the property of non- superimposability on their mirror image partner, while the term "achiral" refers to molecules which are superimposable on their mirror image partner. Therefore, the invention includes enantiomers, diastereomers or racemates of the compound. "Enantiomers" are a pair of stereoisomers that are non- superimposable mirror images of each other. A 1 :1 mixture of a pair of enantiomers is a "racemic" mixture. The term is used to designate a racemic mixture where appropriate. "Diastereoisomers" are stereoisomers that have at least two asymmetric atoms, but which are not mirror-images of each other. The absolute stereochemistry is specified according to the Cahn- Ingold- Prelog R-S system. When a compound is a pure enantiomer the stereochemistry at each chiral carbon may be specified by either R or S.

Resolved compounds whose absolute configuration is unknown can be designated (+) or (-) depending on the direction (dextro- or levorotatory) which they rotate plane polarized light at the wavelength of the sodium D line. Certain compounds described herein contain one or more asymmetric centers or axes and may thus give rise to enantiomers, diastereomers, and other stereoisomeric forms that may be defined, in terms of absolute stereochemistry, as (R)- or (S)-.

[0079] Depending on the choice of the starting materials and procedures, the compounds can be present in the form of one of the possible isomers or as mixtures thereof, for example as pure optical isomers, or as isomer mixtures, such as racemates and

diastereoisomer mixtures, depending on the number of asymmetric carbon atoms. The present invention is meant to include all such possible stereoisomers, including racemic mixtures, diasteriomeric mixtures and optically pure forms. Optically active (R)- and (S)- isomers may be prepared using chiral synthons or chiral reagents, or resolved using conventional techniques. If the compound contains a double bond, the substituent may be E or Z configuration. If the compound contains a disubstituted cycloalkyl, the cycloalkyl substituent may have a cis- or trans-configuration. All tautomeric forms are also intended to be included.

[0080] Any resulting mixtures of isomers can be separated on the basis of the physicochemical differences of the constituents, into the pure or substantially pure geometric or optical isomers or diastereomers, for example, by chromatography and/or fractional crystallization.

[0081] Any resulting racemates of final products or intermediates can be resolved into the optical antipodes by known methods, e.g., by separation of the diastereomeric salts thereof, obtained with an optically active acid or base, and liberating the optically active acidic or basic compound. In particular, a basic moiety may thus be employed to resolve the compounds of the present invention into their optical antipodes, e.g., by fractional crystallization of a salt formed with an optically active acid, e.g., tartaric acid, dibenzoyl tartaric acid, diacetyl tartaric acid, di-0,0'-p-toluoyl tartaric acid, mandelic acid, malic acid or camphor-10-sulfonic acid. Racemic products can also be resolved by chiral chromatography, e.g., high pressure liquid chromatography (HPLC) using a chiral adsorbent.

[0082] Furthermore, the compounds of the present invention, including their salts, can also be obtained in the form of their hydrates, or include other solvents used for their crystallization. The compounds of the present invention may inherently or by design form solvates with pharmaceutically acceptable solvents (including water); therefore, it is intended that the invention embrace both solvated and unsolvated forms. The term "solvate" refers to a molecular complex of a compound of the present invention (including pharmaceutically acceptable salts thereof) with one or more solvent molecules. Such solvent molecules are those commonly used in the pharmaceutical art, which are known to be innocuous to the recipient, e.g., water, ethanol, and the like. The term "hydrate" refers to the complex where the solvent molecule is water. [0083] The compounds of the present invention, including salts, hydrates and solvates thereof, may inherently or by design form polymorphs.

[0084] As used herein, the terms "salt" or "salts" refers to an acid addition or base addition salt of a compound of the present invention. "Salts" include in particular

"pharmaceutically acceptable salts". The term "pharmaceutically acceptable salts" refers to salts that retain the biological effectiveness and properties of the compounds of this invention and, which typically are not biologically or otherwise undesirable. In many cases, the compounds of the present invention are capable of forming acid and/or base salts by virtue of the presence of amino and/or carboxyl groups or groups similar thereto.

[0085] Pharmaceutically acceptable acid addition salts can be formed with inorganic acids and organic acids, e.g., acetate, aspartate, benzoate, besylate, bromide/hydrobromide, bicarbonate/carbonate, bisulfate/sulfate, camphorsulfonate, chloride/hydrochloride,

chlortheophyllonate, citrate, ethandisulfonate, fumarate, gluceptate, gluconate, glucuronate, hippurate, hydroiodide/iodide, isethionate, lactate, lactobionate, laurylsulfate, malate, maleate, malonate, mandelate, mesylate, methylsulphate, naphthoate, napsylate, nicotinate, nitrate, octadecanoate, oleate, oxalate, palmitate, pamoate, phosphate/hydrogen

phosphate/dihydrogen phosphate, polygalacturonate, propionate, stearate, succinate, subsalicylate, tartrate, tosylate and trifluoroacetate salts.

[0086] Inorganic acids from which salts can be derived include, for example, hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like.

[0087] Organic acids from which salts can be derived include, for example, acetic acid, propionic acid, glycolic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, toluenesulfonic acid, sulfosalicylic acid, and the like. Pharmaceutically acceptable base addition salts can be formed with inorganic and organic bases.

[0088] Inorganic bases from which salts can be derived include, for example, ammonium salts and metals from columns I to XII of the periodic table. In certain

embodiments, the salts are derived from sodium, potassium, ammonium, calcium, magnesium, iron, silver, zinc, and copper; particularly suitable salts include ammonium, potassium, sodium, calcium and magnesium salts.

[0089] Organic bases from which salts can be derived include, for example, primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines, basic ion exchange resins, and the like. Certain organic amines include isopropylamine, benzathine, cholinate, diethanolamine, diethylamine, lysine, meglumine, piperazine and tromethamine. [0090] The pharmaceutically acceptable salts of the present invention can be synthesized from a basic or acidic moiety, by conventional chemical methods. Generally, such salts can be prepared by reacting free acid forms of these compounds with a stoichiometric amount of the appropriate base (such as Na, Ca, Mg, or K hydroxide, carbonate, bicarbonate or the like), or by reacting free base forms of these compounds with a stoichiometric amount of the appropriate acid. Such reactions are typically carried out in water or in an organic solvent, or in a mixture of the two. Generally, use of non-aqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile is desirable, where practicable. Lists of additional suitable salts can be found, e.g., in "Remington's Pharmaceutical Sciences", 20th ed., Mack Publishing Company, Easton, Pa., (1985); and in "Handbook of Pharmaceutical Salts: Properties, Selection, and Use" by Stahl and Wermuth (Wiley-VCH, Weinheim, Germany, 2002).

[0091] Any formula given herein is intended to represent unlabeled forms as well as isotopically labeled forms of the compounds of the present invention having up to three atoms with non-natural isotope distributions, e.g., sites that are enriched in deuterium or ¹³C or ¹⁵N. Isotopically labeled compounds have structures depicted by the formulas given herein except that one or more atoms are replaced by an atom having a selected atomic mass or mass number other than the natural-abundance mass distribution. Examples of isotopes that can be usefully over-incorporated into compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, fluorine, and chlorine, such as ²H, ³H, ¹¹C, ¹³C, ¹⁴C, ¹⁵N, ¹⁸F ³¹ P, ³²P, ³⁵S, ³⁶CI, ¹²⁵l respectively. The invention includes various isotopically labeled compounds of the present invention, for example those into which radioactive isotopes, such as ³H and ¹⁴C, or those in which non-radioactive isotopes, such as ²H and ¹³C are present at levels substantially above normal isotope distribution. Such isotopically labelled compounds are useful in metabolic studies (with ¹⁴C, for example), reaction kinetic studies (with, for example ²H or ³H), detection or imaging techniques, such as positron emission tomography (PET) or single- photon emission computed tomography (SPECT) including drug or substrate tissue distribution assays, or in radioactive treatment of patients. In particular, an ¹⁸F labeled compound of the present invention may be particularly desirable for PET or SPECT studies. Isotopically-labeled compounds of the present invention can generally be prepared by conventional techniques known to those skilled in the art or by processes analogous to those described in the accompanying Examples and Preparations using an appropriate isotopically-labeled reagent in place of the non-labeled reagent typically employed. Labeled samples may be useful with quite low isotope incorporation, such as where a radiolabel is used to detect trace amounts of the compound. [0092] Further, site-specific substitution with heavier isotopes, particularly deuterium

(i.e., ²H or D), may afford certain therapeutic advantages resulting from greater metabolic stability, for example increased in vivo half-life or reduced dosage requirements or an improvement in therapeutic index. It is understood that deuterium in this context is regarded as a substituent of a compound of the present invention, and typically a sample of a compound having deuterium as a substituent has at least 50% deuterium incorporation at the labeled position(s). The concentration of such a heavier isotope, specifically deuterium, may be defined by the isotopic enrichment factor. The term "isotopic enrichment factor" as used herein means the ratio between the isotopic abundance and the natural abundance of a specified isotope. If a substituent in a compound of this invention is denoted deuterium, such compound has an isotopic enrichment factor for each designated deuterium atom of at least 3500 (52.5% deuterium incorporation at each designated deuterium atom), at least 4000 (60% deuterium incorporation), at least 4500 (67.5% deuterium incorporation), at least 5000 (75% deuterium incorporation), at least 5500 (82.5% deuterium incorporation), at least 6000 (90% deuterium incorporation), at least 6333.3 (95% deuterium incorporation), at least 6466.7 (97% deuterium incorporation), at least 6600 (99% deuterium incorporation), or at least 6633.3 (99.5% deuterium incorporation).

[0093] Pharmaceutically acceptable solvates in accordance with the invention include those wherein the solvent of crystallization may be isotopically substituted, e.g. D₂0, d⁶- acetone, d⁶-DMSO.

[0094] Compounds of the present invention that contain groups capable of acting as donors and/or acceptors for hydrogen bonds may be capable of forming co-crystals with suitable co-crystal formers. These co-crystals may be prepared from compounds of the present invention by known co-crystal forming procedures. Such procedures include grinding, heating, co-subliming, co-melting, or contacting in solution compounds of the present invention with the co-crystal former under crystallization conditions and isolating co-crystals thereby formed. Suitable co-crystal formers include those described in WO 2004/078163. Hence the invention further provides co-crystals comprising a compound of the present invention.

Methods of Use

[0095] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. [0096] The compounds of the invention can be administered by known methods, including oral, parenteral, inhalation, and the like. In certain embodiments, the compound of the invention is administered orally, as a pill, lozenge, troche, capsule, solution, or suspension. In other embodiments, a compound of the invention is administered by injection or infusion. Infusion is typically performed intravenously, often over a period of time between about 15 minutes and 4 hours. In other embodiments, a compound of the invention is administered intranasally or by inhalation; inhalation methods are particularly useful for treatment of respiratory infections. Compounds of the present invention exhibit oral bioavailability, so oral administration is sometimes preferred.

[0097] In certain embodiments of the present invention, a compound of the present invention is used in combination with a second antiviral agent, such as those named herein.

[0098] By the term "combination", is meant either a fixed combination in one dosage unit form, as separate dosage forms suitable for use together either simultaneously or sequentially, or as a kit of parts for the combined administration where a compound of the present invention and a combination partner may be administered independently at the same time or separately within time intervals that especially allow that the combination partners show a cooperative, e.g., synergistic, effect, or any combination thereof.

[0099] The second antiviral agent may be administered in combination with the compounds of the present inventions wherein the second antiviral agent is administered prior to, simultaneously, or after the compound or compounds of the present invention. When simultaneous administration of a compound of the invention with a second agent is desired and the route of administration is the same, then a compound of the invention may be formulated with a second agent into the same dosage form. An example of a dosage form containing a compound of the invention and a second agent is a tablet or a capsule.

[00100] In some embodiments, a combination of a compound of the invention and a second antiviral agent may provide synergistic activity. The compound of the invention and second antiviral agent may be administered together, separate but simultaneously, or sequentially.

[00101] An "effective amount" of a compound is that amount necessary or sufficient to treat or prevent a viral infection and/or a disease or condition described herein. In an example, an effective amount of a compound of Formula I is an amount sufficient to treat viral infection in a subject. In another example, an effective amount is an amount sufficient to treat HBV in a subject in need of such treatment. The effective amount can vary depending on such factors as the size and weight of the subject, the type of illness, or the particular compound of the invention. For example, the choice of the compound of the invention can affect what constitutes an "effective amount." One of ordinary skill in the art would be able to study the factors contained herein and make the determination regarding the effective amount of the compounds of the invention without undue experimentation.

[00102] The regimen of administration can affect what constitutes an effective amount. The compound of the invention can be administered to the subject either prior to or after the onset of a viral infection. Further, several divided dosages, as well as staggered dosages, can be administered daily or sequentially, or the dose can be continuously infused, or can be a bolus injection. Further, the dosages of the compound(s) of the invention can be proportionally increased or decreased as indicated by the exigencies of the therapeutic or prophylactic situation.

[00103] Compounds of the invention may be used in the treatment of states, disorders or diseases as described herein, or for the manufacture of pharmaceutical compositions for use in the treatment of these diseases. The invention provides methods of use of compounds of the present invention in the treatment of these diseases or for preparation of pharmaceutical compositions having compounds of the present invention for the treatment of these diseases.

[00104] The language "pharmaceutical composition" includes preparations suitable for administration to mammals, e.g., humans. When the compounds of the present invention are administered as pharmaceuticals to mammals, e.g., humans, they can be given per se or as a pharmaceutical composition containing, for example, 0.1 to 99.5% (more preferably, 0.5 to 90%) of at least one compound of Formula (I) or any subgenus thereof as active ingredient in combination with a pharmaceutically acceptable carrier, or optionally two or more

pharmaceutically acceptable carriers.

[00105] The phrase "pharmaceutically acceptable carrier" is art recognized and includes a pharmaceutically acceptable material, composition or vehicle, suitable for administering compounds of the present invention to mammals. The carriers include liquid or solid filler, diluent, excipient, solvent or encapsulating material, involved in carrying or transporting the subject agent from one organ, or portion of the body, to another organ, or portion of the body. Each carrier must be "acceptable" in the sense of being compatible with the other ingredients of the formulation and not injurious to the patient. Some examples of materials which can serve as pharmaceutically acceptable carriers include: sugars, such as lactose, glucose and sucrose; starches, such as corn starch and potato starch; cellulose, and its derivatives, such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients, such as cocoa butter and suppository waxes; oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; glycols, such as propylene glycol; polyols, such as glycerin, sorbitol, mannitol and polyethylene glycol; esters, such as ethyl oleate and ethyl laurate; agar; buffering agents, such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer's solution; ethyl alcohol; phosphate buffer solutions; and other non-toxic compatible substances employed in pharmaceutical formulations. Typically, pharmaceutically acceptable carriers are sterilized and/or substantially pyrogen-free.

[00106] Wetting agents, emulsifiers and lubricants, such as sodium lauryl sulfate and magnesium stearate, as well as coloring agents, release agents, coating agents, sweetening, flavoring and perfuming agents, preservatives and antioxidants can also be present in the compositions.

[00107] Examples of pharmaceutically acceptable antioxidants include: water soluble antioxidants, such as ascorbic acid, cysteine hydrochloride, sodium bisulfate, sodium metabisulfite, sodium sulfite and the like; oil-soluble antioxidants, such as ascorbyl palmitate, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), lecithin, propyl gallate, a- tocopherol, and the like; and metal chelating agents, such as citric acid, ethylenediamine tetraacetic acid (EDTA), sorbitol, tartaric acid, phosphoric acid, and the like.

[00108] Formulations of the present invention include those suitable for oral, nasal, inhalation, topical, transdermal, buccal, sublingual, rectal, vaginal and/or parenteral

administration. The formulations may conveniently be presented in unit dosage form and may be prepared by any methods well known in the art of pharmacy. The amount of active ingredient that can be combined with a carrier material to produce a single dosage form will generally be that amount of the compound that produces a therapeutic effect. Generally, out of one hundred per cent, this amount will range from about 1 per cent to about ninety-nine percent of active ingredient, preferably from about 5 per cent to about 70 per cent, most preferably from about 10 per cent to about 30 per cent.

[00109] Methods of preparing these formulations or compositions include the step of bringing into association a compound of the present invention with the carrier and, optionally, one or more accessory ingredients. In general, the formulations are prepared by uniformly and intimately bringing into association a compound of the present invention with liquid carriers, or finely divided solid carriers, or both, and then, if necessary, shaping the product.

[00110] Formulations of the invention suitable for oral administration may be in the form of capsules, cachets, pills, tablets, lozenges (using a flavored base, for example, usually sucrose and acacia or tragacanth), powders, granules, or as a solution or a suspension in an aqueous or non-aqueous liquid, or as an oil-in-water or water-in-oil liquid emulsion, or as an elixir or syrup, or as pastilles (using an inert base, such as gelatin and glycerin, or sucrose and acacia) and/or as mouth washes and the like, each containing a predetermined amount of a compound of the present invention as an active ingredient. A compound of the present invention may also be administered as a bolus, electuary or paste.

[00111] In solid dosage forms of the invention for oral administration (capsules, tablets, pills, dragees, powders, granules and the like), the active ingredient is mixed with one or more pharmaceutically acceptable carriers, such as sodium citrate or dicalcium phosphate, and/or any of the following: fillers or extenders, such as starches, lactose, sucrose, glucose, mannitol, and/or silicic acid; binders, such as, for example, carboxymethylcellulose, alginates, gelatin, polyvinyl pyrrolidone, sucrose and/or acacia; humectants, such as glycerol; disintegrating agents, such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and sodium carbonate; solution retarding agents, such as paraffin; absorption accelerators, such as quaternary ammonium compounds; wetting agents, such as, for example, cetyl alcohol and glycerol monostearate; absorbents, such as kaolin and bentonite clay; lubricants, such a talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and mixtures thereof; and coloring agents. In the case of capsules, tablets and pills, the pharmaceutical compositions may also comprise buffering agents. Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugars, as well as high molecular weight polyethylene glycols and the like.

[00112] A tablet may be made by compression or molding, optionally with one or more accessory ingredients. Compressed tablets may be prepared using binder (for example, gelatin or hydroxypropylmethyl cellulose), lubricant, inert diluent, preservative, disintegrant (for example, sodium starch glycolate or cross-linked sodium carboxymethyl cellulose), surface- active or dispersing agent. Molded tablets may be made by molding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent.

[00113] The tablets, and other solid dosage forms of the pharmaceutical compositions of the present invention, such as dragees, capsules, pills and granules, may optionally be scored or prepared with coatings and shells, such as enteric coatings and other coatings well known in the pharmaceutical-formulating art. They may also be formulated so as to provide slow or controlled release of the active ingredient therein using, for example, hydroxypropylmethyl cellulose in varying proportions to provide the desired release profile, other polymer matrices, liposomes and/or microspheres. They may be sterilized by, for example, filtration through a bacteria-retaining filter, or by incorporating sterilizing agents in the form of sterile solid compositions that can be dissolved in sterile water, or some other sterile injectable medium immediately before use. These compositions may also optionally contain opacifying agents and may be of a composition that they release the active ingredient(s) only, or preferentially, in a certain portion of the gastrointestinal tract, optionally, in a delayed manner. Examples of embedding compositions that can be used include polymeric substances and waxes. The active ingredient can also be in micro-encapsulated form, if appropriate, with one or more of the above-described excipients.

[00114] Liquid dosage forms for oral administration of the compounds of the invention include pharmaceutically acceptable emulsions, microemulsions, solutions, suspensions, syrups and elixirs. In addition to the active ingredient, the liquid dosage forms may contain inert diluent commonly used in the art, such as, for example, 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, oils (in particular, cottonseed, groundnut, corn, germ, olive, castor and sesame oils), glycerol, tetrahydrofuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof.

[00115] Besides inert diluents, the oral compositions can also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, coloring, perfuming and preservative agents.

[00116] Suspensions, in addition to the active compounds, may contain suspending agents as, for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar and tragacanth, and mixtures thereof.

[00117] Formulations of the pharmaceutical compositions of the invention for rectal or vaginal administration may be presented as a suppository, which may be prepared by mixing one or more compounds of the invention with one or more suitable nonirritating excipients or carriers comprising, for example, cocoa butter, polyethylene glycol, a suppository wax or a salicylate, and which is solid at room temperature, but liquid at body temperature and, therefore, will melt in the rectum or vaginal cavity and release the active compound.

[00118] Formulations of the present invention which are suitable for vaginal

administration also include pessaries, tampons, creams, gels, pastes, foams or spray formulations containing such carriers as are known in the art to be appropriate.

[00119] Dosage forms for the topical or transdermal administration of a compound of this invention include powders, sprays, ointments, pastes, creams, lotions, gels, solutions, patches and inhalants. The active compound may be mixed under sterile conditions with a

pharmaceutically acceptable carrier, and with any preservatives, buffers, or propellants that may be required. [00120] The ointments, pastes, creams and gels may contain, in addition to an active compound of this invention, excipients, such as animal and vegetable fats, oils, waxes, paraffins, starch, tragacanth, cellulose derivatives, polyethylene glycols, silicones, bentonites, silicic acid, talc and zinc oxide, or mixtures thereof.

[00121] Powders and sprays can contain, in addition to a compound of this invention, excipients such as lactose, talc, silicic acid, aluminum hydroxide, calcium silicates and polyamide powder, or mixtures of these substances. Sprays can additionally contain customary propellants, such as chlorofluorohydrocarbons and volatile unsubstituted hydrocarbons, such as butane and propane.

[00122] Transdermal patches have the added advantage of providing controlled delivery of a compound of the present invention to the body. Such dosage forms can be made by dissolving or dispersing the compound in the proper medium. Absorption enhancers can also be used to increase the flux of the compound across the skin. The rate of such flux can be controlled by either providing a rate controlling membrane or dispersing the active compound in a polymer matrix or gel.

[00123] Ophthalmic formulations, eye ointments, powders, solutions and the like, are also contemplated as being within the scope of this invention.

[00124] Pharmaceutical compositions of this invention suitable for parenteral administration may comprise one or more compounds of the invention in combination with one or more pharmaceutically acceptable carriers such as sterile isotonic aqueous or nonaqueous solutions, dispersions, suspensions or emulsions, or sterile powders which may be

reconstituted into sterile injectable solutions or dispersions just prior to use, which may contain antioxidants, buffers, bacteriostats, solutes which render the formulation isotonic with the blood of the intended recipient or suspending or thickening agents.

[00125] Examples of suitable aqueous and nonaqueous carriers that may be employed in the pharmaceutical compositions of the invention include water, ethanol, glycol ethers, polyols (such as glycerol, propylene glycol, polyethylene glycol, and the like), and suitable mixtures thereof, vegetable oils, such as olive oil, and injectable organic esters, such as ethyl oleate. Proper fluidity can be maintained, for example, by the use of coating materials, such as lecithin, by the maintenance of the required particle size in the case of dispersions, and by the use of surfactants.

[00126] These compositions may also contain adjuvants such as preservatives, wetting agents, emulsifying agents and dispersing agents. Prevention of the action of microorganisms may be ensured by the inclusion of various antibacterial and antifungal agents, for example, paraben, chlorobutanol, phenol sorbic acid, and the like. It may also be desirable to include isotonic agents, such as sugars, sodium chloride, and the like into the compositions. In addition, prolonged absorption of the injectable pharmaceutical form may be brought about by the inclusion of agents that delay absorption such as aluminum monostearate and gelatin.

[00127] In some cases, in order to prolong the effect of a drug, it is desirable to slow the absorption of the drug from subcutaneous or intramuscular injection. This may be

accomplished by the use of a liquid suspension of crystalline or amorphous material having poor water solubility. The rate of absorption of the drug then depends upon its rate of dissolution which, in turn, may depend upon crystal size and crystalline form. Alternatively, delayed absorption of a parenterally-administered drug form is accomplished by dissolving or suspending the drug in an oil vehicle.

[00128] Injectable depot forms are made by forming microencapsule matrices of the subject compounds in biodegradable polymers such as polylactide-polyglycolide. Depending on the ratio of drug to polymer, and the nature of the particular polymer employed, the rate of drug release can be controlled. Examples of other biodegradable polymers include poly(orthoesters) and poly(anhydrides). Depot injectable formulations are also prepared by entrapping the drug in liposomes or microemulsions that are compatible with body tissue.

[00129] The preparations of the present invention may be given orally, parenterally, topically, or rectally. They are of course given by forms suitable for each administration route. For example, they are administered in tablets or capsule form, by injection, inhalation, eye lotion, ointment, suppository, etc., administration by injection, infusion or inhalation; topical by lotion or ointment; and rectal by suppositories.

[00130] The phrases "parenteral administration" and "administered parenterally" as used herein means modes of administration other than enteral and topical administration, usually by injection, and includes, without limitation, intravenous, intramuscular, intraarterial, intrathecal, intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal, transtracheal,

subcutaneous, subcuticular, intraarticular, subcapsular, subarachnoid, intraspinal and intrasternal injection and infusion. Intravenous infusion is sometimes a preferred method of delivery for compounds of the invention. Infusion may be used to deliver a single daily dose or multiple doses. In some embodiments, a compound of the invention is administered by infusion over an interval between 15 minutes and 4 hours, typically between 0.5 and 3 hours. Such infusion may be used once per day, twice per day or up to three times per day.

[00131] The phrases "systemic administration," "administered systemically," "peripheral administration" and "administered peripherally" as used herein mean the administration of a compound, drug or other material other than directly into the central nervous system, such that it enters the patient's system and, thus, is subject to metabolism and other like processes, for example, subcutaneous administration.

[00132] These compounds may be administered to humans and other animals for therapy by any suitable route of administration, including orally, nasally, as by, for example, a spray, rectally, intravaginally, parenterally, intracisternally and topically, as by powders, ointments or drops, including buccally and sublingually.

[00133] Regardless of the route of administration selected, the compounds of the present invention, which may be used in a suitable hydrated form, and/or the pharmaceutical compositions of the present invention, are formulated into pharmaceutically acceptable dosage forms by conventional methods known to those of skill in the art.

[00134] Actual dosage levels of the active ingredients in the pharmaceutical

compositions of this invention may be varied so as to obtain an amount of the active ingredient which is effective to achieve the desired therapeutic response for a particular patient, composition, and mode of administration, without being toxic to the patient.

[00135] The selected dosage level will depend upon a variety of factors including the activity of the particular compound of the present invention employed, or the ester, salt or amide thereof, the route of administration, the time of administration, the rate of excretion of the particular compound being employed, the duration of the treatment, other drugs, compounds and/or materials used in combination with the particular compound employed, the age, sex, weight, condition, general health and prior medical history of the patient being treated, and like factors well known in the medical arts.

[00136] A physician or veterinarian having ordinary skill in the art can readily determine and prescribe the effective amount of the pharmaceutical composition required. For example, the physician or veterinarian could start doses of the compounds of the invention employed in the pharmaceutical composition at levels lower than that required in order to achieve the desired therapeutic effect and gradually increase the dosage until the desired effect is achieved.

[00137] In general, a suitable daily dose of a compound of the invention will be that amount of the compound that is the lowest dose effective to produce a therapeutic effect. Such an effective dose will generally depend upon the factors described above. Generally, intravenous and subcutaneous doses of the compounds of this invention for a patient, when used for the indicated effects, will range from about 0.0001 to about 100 mg per kilogram of body weight per day, more preferably from about 0.01 to about 50 mg per kg per day, and still more preferably from about 0.1 to about 20 mg per kg per day. An effective amount is that amount which prevents or treats a viral infection, such as HBV. [00138] Treatment with a compound or composition described herein may be repeated daily for a period sufficient to reduce or substantially eliminate an HBV infection or viral load. For example, treatment may be continued for a week, or two weeks, or 3-4 weeks, or 4-8 weeks, or 8-12 weeks, 2-6 months, or longer, e.g., until viral load or other measure of infection shows a substantial reduction in viral load or viral activity or other signs or symptoms of HBV infection. The skilled treating physician can readily determine a suitable duration of treatment.

[00139] If desired, the effective daily dose of the active compound may be administered as a single dose per day, or as two, three, four, five, six or more sub-doses administered separately at appropriate intervals throughout the day, optionally, in unit dosage forms.

Compounds delivered orally or by inhalation, are commonly administered in one to four doses per day. Compounds delivered by injection are typically administered once per day, or once every other day. Compounds delivered by infusion are typically administered in one to three doses per day. When multiple doses are administered within a day, the doses may be administered at intervals of about 4 hours, about 6 hours, about 8 hours or about 12 hours.

[00140] While it is possible for a compound of the present invention to be administered alone, it is preferable to administer the compound as a pharmaceutical composition such as those described herein. Thus methods of using the compounds of the invention include administering the compound as a pharmaceutical composition, wherein at least one compound of the invention is admixed with a pharmaceutically acceptable carrier prior to administration.

Use of Compounds of the Invention in combination with immunomodulators

[00141] The compounds and compositions described herein can be used or

administered in combination with one or more therapeutic agents that act as

immunomodulators, e.g., an activator of a costimulatory molecule, or an inhibitor of an immune- inhibitory molecule, or a vaccine. The Programmed Death 1 (PD-1 ) protein is an inhibitory member of the extended CD28/CTLA4 family of T cell regulators (Okazaki et al. (2002) Curr. Opin. Immunol. 14: 391779-82; Bennett et al. (2003) J. Immunol. 170:71 1 -8). PD-1 is expressed on activated B cells, T cells, and monocytes. PD-1 is an immune-inhibitory protein that negatively regulates TCR signals (Ishida, Y. et al. (1992) EMBO J. 1 1 :3887-3895; Blank, C. et al. (Epub 2006 Dec. 29) Immunol. Immunother. 56(5):739-745), and is up-regulated in chronic infections. The interaction between PD-1 and PD-L1 can act as an immune

checkpoint, which can lead to, e.g., a decrease in infiltrating lymphocytes, a decrease in T-cell receptor mediated proliferation, and/or immune evasion by cancerous or infected cells (Dong et al. (2003) J. Mol. Med. 81 :281 -7; Blank et al. (2005) Cancer Immunol. Immunother. 54:307- 314; Konishi et al. (2004) Clin. Cancer Res. 10:5094-100). Immune suppression can be reversed by inhibiting the local interaction of PD-1 with PD-L1 or PD-L2; the effect is additive when the interaction of PD-1 with PD-L2 is blocked as well (Iwai et al. (2002) Proc. Nat'l. Acad. Sci. USA 99:12293-7; Brown et al. (2003) J. Immunol. 170:1257-66). Immunomodulation can be achieved by binding to either the immune-inhibitory protein (e.g., PD-1 ) or to binding proteins that modulate the inhibitory protein (e.g., PD-L1 , PD-L2).

[00142] In one embodiment, the combination therapies of the invention include an immunomodulator that is an inhibitor or antagonist of an inhibitory molecule of an immune checkpoint molecule. In another embodiment the immunomodulator binds to a protein that naturally inhibits the immuno-inhibitory checkpoint molecule. When used in combination with antiviral compounds, these immunomodulators can enhance the antiviral response, and thus enhance efficacy relative to treatment with the antiviral compound alone.

[00143] The term "immune checkpoints" refers to a group of molecules on the cell surface of CD4 and CD8 T cells. These molecules can effectively serve as "brakes" to down- modulate or inhibit an adaptive immune response. Immune checkpoint molecules include, but are not limited to, Programmed Death 1 (PD-1 ), Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4), B7H1 , B7H4, OX-40, CD137, CD40, and LAG3, which directly inhibit immune cells.

Immunotherapeutic agents which can act as immune checkpoint inhibitors useful in the methods of the present invention, include, but are not limited to, inhibitors of PD-L1 , PD-L2, CTLA4, TIM3, LAG3, VISTA, BTLA, TIGIT, LAIR1 , CD160, 2B4 and/or TGFR beta. Inhibition of an inhibitory molecule can be performed by inhibition at the DNA, RNA or protein level. In some embodiments, an inhibitory nucleic acid (e.g., a dsRNA, siRNA or shRNA), can be used to inhibit expression of an inhibitory molecule. In other embodiments, the inhibitor of an inhibitory signal is a polypeptide, e.g., a soluble ligand, or an antibody or antigen-binding fragment thereof, that binds to the inhibitory molecule.

[00144] By "in combination with," it is not intended to imply that the therapy or the therapeutic agents must be administered at the same time and/or formulated for delivery together, although these methods of delivery are within the scope described herein. The immunomodulator can be administered concurrently with, prior to, or subsequent to, one or more compounds of the invention, and optionally one or more additional therapies or therapeutic agents. The therapeutic agents in the combination can be administered in any order. In general, each agent will be administered at a dose and/or on a time schedule determined for that agent. It will further be appreciated that the therapeutic agents utilized in this combination may be administered together in a single composition or administered separately in different compositions. In general, it is expected that each of the therapeutic agents utilized in combination be utilized at levels that do not exceed the levels at which they are utilized individually. In some embodiments, the levels utilized in combination will be lower than those utilized individually.

[00145] In certain embodiments, the antiviral compounds described herein are administered in combination with one or more immunomodulators that are inhibitors of PD-1 , PD-L1 and/or PD-L2. Each such inhibitor may be an antibody, an antigen binding fragment thereof, an immunoadhesin, a fusion protein, or an oligopeptide. Examples of such

immunomodulators are known in the art.

[00146] In some embodiments, the immunomodulator is an anti-PD-1 antibody chosen from MDX-1 106, Merck 3475 or CT- 01 1 .

[00147] In some embodiments, the immunomodulator is an immunoadhesin (e.g., an immunoadhesin comprising an extracellular or PD-1 binding portion of PD-LI or PD-L2 fused to a constant region (e.g., an Fc region of an immunoglobulin sequence).

[00148] In some embodiments, the immunomodulator is a PD-1 inhibitor such as AMP-

224.

[00149] In some embodiments, the immunomodulator is a PD-LI inhibitor such as anti- PD-LI antibody.

[00150] In some embodiments, the immunomodulator is an anti-PD-LI binding antagonist chosen from YW243.55.S70, MPDL3280A, MEDI-4736, MSB-0010718C, or MDX-1 105. MDX- 1 105, also known as BMS-936559, is an anti-PD-LI antibody described in WO2007/005874. Antibody YW243.55.S70 is an anti-PD-LI described in WO 2010/077634.

[00151] In some embodiments, the immunomodulator is nivolumab (CAS Registry Number: 946414-94-4). Alternative names for nivolumab include MDX-1 106, MDX-1 106-04, ONO-4538, or BMS-936558. Nivolumab is a fully human lgG4 monoclonal antibody which specifically blocks PD-1 . Nivolumab (clone 5C4) and other human monoclonal antibodies that specifically bind to PD-1 are disclosed in US 8,008,449, EP2161336 and WO2006/121 168.

[00152] In some embodiments, the immunomodulator is an anti-PD-1 antibody

Pembrolizumab. Pembrolizumab (also referred to as Lambrolizumab, MK-3475, MK03475, SCH-900475 or KEYTRUDA®; Merck) is a humanized lgG4 monoclonal antibody that binds to PD-1 . Pembrolizumab and other humanized anti-PD-1 antibodies are disclosed in Hamid, O. et al. (2013) New England Journal of Medicine 369 (2): 134-44, US 8,354,509, WO2009/1 14335, and WO2013/079174.

[00153] In some embodiments, the immunomodulator is Pidilizumab (CT-01 1 ; Cure Tech), a humanized lgG1 k monoclonal antibody that binds to PD1 . Pidilizumab and other humanized anti-PD-1 monoclonal antibodies are disclosed in WO2009/10161 1 . [00154] Other anti-PD1 antibodies useful as immunomodulators for use in the methods disclosed herein include AMP 514 (Amplimmune), and anti-PD1 antibodies disclosed in US 8,609,089, US 2010028330, and/or US 201201 14649. In some embodiments, the anti-PD-L1 antibody is MSB0010718C. MSB0010718C (also referred to as A09-246-2; Merck Serono) is a monoclonal antibody that binds to PD-L1 .

[00155] In some embodiments, the immunomodulator is MDPL3280A (Genentech / Roche), a human Fc optimized lgG1 monoclonal antibody that binds to PD-L1 . MDPL3280A and other human monoclonal antibodies to PD-L1 are disclosed in U.S. Patent No.: 7,943,743 and U.S Publication No.: 20120039906. Other anti-PD-L1 binding agents useful as immunomodulators for methods of the invention include YW243.55.S70 (see

WO2010/077634), MDX-1 105 (also referred to as BMS-936559), and anti-PD-L1 binding agents disclosed in WO2007/005874.

[00156] In some embodiments, the immunomodulator is AMP-224 (B7-DCIg;

Amplimmune; e.g., disclosed in WO2010/027827 and WO201 1/066342), is a PD-L2 Fc fusion soluble receptor that blocks the interaction between PD1 and B7-H1 .

[00157] In some embodiments, the immunomodulator is an anti-LAG-3 antibody such as BMS-986016. BMS-986016 (also referred to as BMS986016) is a monoclonal antibody that binds to LAG -3. BMS-986016 and other humanized anti-LAG-3 antibodies are disclosed in US 201 1/0150892, WO2010/019570, and WO2014/008218

[00158] In certain embodiments, the combination therapies disclosed herein include a modulator of a costimulatory molecule or an inhibitory molecule, e.g., a co-inhibitory ligand or receptor.

[00159] In one embodiment, the costimulatory modulator, e.g., agonist, of a

costimulatory molecule is chosen from an agonist (e.g., an agonistic antibody or antigen- binding fragment thereof, or soluble fusion) of OX40, CD2, CD27, CDS, ICAM-1 , LFA-1 (CD1 1 a/CD18), ICOS (CD278), 4-1 BB (CD137), GITR, CD30, CD40, BAFFR, HVEM, CD7, LIGHT, NKG2C, SLAMF7, NKp80, CD160, B7-H3 or CD83 ligand.

[00160] In another embodiment, the combination therapies disclosed herein include an immunomodulator that is a costimulatory molecule, e.g., an agonist associated with a positive signal that includes a costimulatory domain of CD28, CD27, ICOS and/or GITR.

[00161] Exemplary GITR agonists include, e.g., GITR fusion proteins and anti-GITR antibodies (e.g., bivalent anti-GITR antibodies), such as, a GITR fusion protein described in U.S. Patent No.: 6,1 1 1 ,090, European Patent No.: 090505B1 , U.S Patent No.: 8,586,023, PCT Publication Nos.: WO 2010/0031 18 and 201 1 /090754, or an anti-GITR antibody described, e.g., in U.S. Patent No.: 7,025,962, European Patent No.: 1947183B1 , U.S. Patent No.: 7,812,135, U.S. Patent No.: 8,388,967, U.S. Patent No.: 8,591 ,886, European Patent No.: EP 1866339, PCT Publication No.: WO 201 1 /028683, PCT Publication No.: WO 2013/039954, PCT Publication No.: WO2005/007190, PCT Publication No.: WO 2007/133822, PCT

Publication No.: WO2005/055808, PCT Publication No.: WO 99/40196, PCT Publication No.: WO 2001 /03720, PCT Publication No.: WO99/20758, PCT Publication No.: WO2006/083289, PCT Publication No.: WO 2005/1 15451 , U.S. Patent No.: 7,618,632, and PCT Publication No.: WO 201 1 /051726.

[00162] In one embodiment, the immunomodulator used is a soluble ligand (e.g., a CTLA-4-lg), or an antibody or antibody fragment that binds to PD-L1 , PD-L2 or CTLA4. For example, the anti-PD-1 antibody molecule can be administered in combination with an anti- CTLA-4 antibody, e.g., ipilimumab, for example. Exemplary anti-CTLA4 antibodies include Tremelimumab (lgG2 monoclonal antibody available from Pfizer, formerly known as ticilimumab, CP-675,206); and Ipilimumab (CTLA-4 antibody, also known as MDX-010, CAS No. 477202-00-9).

[00163] In one embodiment, an anti-PD-1 antibody molecule is administered after treatment with a compound of the invention as described herein.

[00164] In another embodiment, an anti-PD-1 or PD-L1 antibody molecule is administered in combination with an anti-LAG-3 antibody or an antigen-binding fragment thereof. In another embodiment, the anti-PD-1 or PD-L1 antibody molecule is administered in combination with an anti-TIM-3 antibody or antigen-binding fragment thereof. In yet other embodiments, the anti-PD-1 or PD-L1 antibody molecule is administered in combination with an anti-LAG-3 antibody and an anti-TIM-3 antibody, or antigen-binding fragments thereof. The combination of antibodies recited herein can be administered separately, e.g., as separate antibodies, or linked, e.g., as a bispecific or trispecific antibody molecule. In one embodiment, a bispecific antibody that includes an anti-PD-1 or PD-L1 antibody molecule and an anti-TIM-3 or anti-LAG-3 antibody, or antigen-binding fragment thereof, is administered. In certain embodiments, the combination of antibodies recited herein is used to treat a cancer, e.g., a cancer as described herein (e.g., a solid tumor). The efficacy of the aforesaid combinations can be tested in animal models known in the art. For example, the animal models to test the synergistic effect of anti-PD-1 and anti-LAG-3 are described, e.g., in Woo et al. (2012) Cancer Res. 72(4):917-27).

[00165] Exemplary immunomodulators that can be used in the combination therapies include, but are not limited to, e.g., afutuzumab (available from Roche®); pegfilgrastim

(Neulasta®); lenalidomide (CC-5013, Revlimid®); thalidomide (Thalomid®), actimid (CC4047); and cytokines, e.g., IL-21 or IRX-2 (mixture of human cytokines including interleukin 1 , interleukin 2, and interferon γ, CAS 951209-71 -5, available from I RX Therapeutics).

[00166] Exemplary doses of such immunomodulators that can be used in combination with the antiviral compounds of the invention include a dose of anti-PD-1 antibody molecule of about 1 to 10 mg/kg, e.g., 3 mg/kg, and a dose of an anti-CTLA-4 antibody, e.g., ipilimumab, of about 3 mg/kg.

[00167] Examples of embodiments of the methods of using the antiviral compounds of the invention in combination with an immunomodulator include these, which may be used along with a compound of Formula I or any subgenus or species thereof that is disclosed herein:

[00168] i. A method to treat a viral infection in a subject, comprising administering to the subject a compound of Formula (I) as described herein, and an immunomodulator.

[00169] ii. The method of embodiment i, wherein the immunomodulator is an activator of a costimulatory molecule or an inhibitor of an immune checkpoint molecule.

[00170] iii. The method of either of embodiments i and ii, wherein the activator of the costimulatory molecule is an agonist of one or more of OX40, CD2, CD27, CDS, ICAM-1 , LFA-

1 (CD1 1 a/CD18), ICOS (CD278), 4-1 BB (CD137), GITR, CD30, CD40, BAFFR, HVEM, CD7,

LIGHT, NKG2C, SLAMF7, NKp80, CD160, B7-H3 and CD83 ligand.

[00171] iv. The method of any of embodiments i-iii above, wherein the inhibitor of the immune checkpoint molecule is chosen from PD-1 , PD-L1 , PD-L2, CTLA4, TIM3, LAG3,

VISTA, BTLA, TIGIT, LAIR1 , CD160, 2B4 and TGFR beta.

[00172] v. The method of any of any of embodiments i-iii, wherein the inhibitor of the immune checkpoint molecule is chosen from an inhibitor of PD-1 , PD-L1 , LAG-3, TIM-3 or CTLA4, or any combination thereof.

[00173] vi. The method of any of embodiments i-v, wherein the inhibitor of the immune checkpoint molecule is a soluble ligand or an antibody or antigen-binding fragment thereof, that binds to the immune checkpoint molecule.

[00174] vii. The method of any of embodiments i-vi, wherein the antibody or antigen- binding fragment thereof is from an lgG1 or lgG4 (e.g., human lgG1 or lgG4).

[00175] viii. The method of any of embodiments i-vii, wherein the antibody or antigen- binding fragment thereof is altered, e.g., mutated, to increase or decrease one or more of: Fc receptor binding, antibody glycosylation, the number of cysteine residues, effector cell function, or complement function.

[00176] ix. The method of any of embodiments i-viii, wherein the antibody molecule is a bispecific or multispecific antibody molecule that has a first binding specificity to PD-1 or PD-L1 and a second binding specificity to TIM-3, LAG-3, or PD-L2. [00177] x. The method of any of embodiments i-ix, wherein the immunomodulator is an anti-PD-1 antibody chosen from Nivolumab, Pembrolizumab or Pidilizumab.

[00178] xi. The method of any of embodiments i-x, wherein the immunomodulator is an anti-PD-L1 antibody chosen from YW243.55.S70, MPDL3280A, MEDI-4736, MSB-001 0718C, or MDX-1 1 05.

[00179] xii. The method of any of embodiments i-x, wherein the immunomodulator is an anti-LAG-3 antibody molecule.

[00180] xiii. The method of embodiment xii, wherein the anti-LAG-3 antibody molecule is BMS-986016.

[00181] xiv. The method of any of embodiments i-x, wherein the immunomodulator is an anti-PD-1 antibody molecule administered by injection (e.g., subcutaneously or intravenously) at a dose of about 1 to 30 mg/kg, e.g., about 5 to 25 mg/kg, about 1 0 to 20 mg/kg, about 1 to 5 mg/kg, or about 3 mg/kg., e.g., once a week to once every 2, 3, or 4 weeks.

[00182] xv. The method of embodiment xiv, wherein the anti-PD-1 antibody molecule is administered at a dose from about 1 0 to 20 mg/kg every other week.

[00183] xvi. The method of embodiment xv, wherein the anti-PD-1 antibody molecule, e.g., nivolumab, is administered intravenously at a dose from about 1 mg/kg to 3 mg/kg, e.g., about 1 mg/kg, 2 mg/kg or 3 mg/kg, every two weeks.

[00184] xvii. The method of embodiment xv, wherein the anti-PD-1 antibody molecule, e.g., nivolumab, is administered intravenously at a dose of about 2 mg/kg at 3-week intervals.

[00185] The compounds as described herein may be synthesized by the general synthetic routes below, specific examples of which are described in more detail in the

Examples.

General Synthetic Procedures

[00186] All starting materials, building blocks, reagents, acids, bases, dehydrating agents, solvents, and catalysts utilized to synthesize the compounds of the invention are either commercially available or can be produced by organic synthesis methods known to one of ordinary skill in the art (Houben-Weyl 4th Ed. 1952, Methods of Organic Synthesis, Thieme, Volume 21 ). General methods for synthesis of compounds of the invention are illustrated by the Examples below, the general method in Scheme 1 , and by methods disclosed in published PCT applications WO2015/1 13990 and WO201 5/1731 64.

LIST OF ABBREVIATIONS

Ac acetyl ACN acetonitrile

AcOEt / EtOAc ethyl acetate

AcOH acetic acid

aq aqueous

Bn benzyl

Bu butyl (nBu = n-butyl, tBu = tert-butyl)

CDI Carbonyldiimidazole

DBU 1 ,8-Diazabicyclo[5.4.0]-undec-7-ene

Boc20 di-tert-butyl dicarbonate

DCE 1 ,2-Dichloroethane

DCM Dichloromethane

DIAD Diisopropyl azodicarboxylate

DiBAI-H Diisobutylaluminum Hydride

DIPEA N-Ethyldiisopropylamine

DMA N,N-dimethylacetamide

DMAP Dimethylaminopyridine

DMF N,N'-Dimethylformamide

DMSO Dimethylsulfoxide

EDCI 1 -Ethyl-3-(3-dimethylaminopropyl)carbodiimide

El Electrospray ionisation

Et₂0 Diethylether

Et₃N Triethylamine

Ether Diethylether

EtOAc Ethyl acetate

EtOH Ethanol

FA Formic acid

FC Flash Chromatography

h hour(s)

HCI Hydrochloric acid

HOBt 1 -Hydroxybenzotriazole

HPLC High Performance Liquid Chromatography

H₂0 water

I PA isopropanol

L liter(s)

LC-MS Liquid Chromatography Mass Spectrometry □ HMDS Lithium bis(trimethylsilyl)amide

Me methyl

Mel lodomethane

MeOH Methanol

mg milligram

min minute(s)

ml_ milliliter

MS Mass Spectrometry

Pd/C palladium on charcoal

PG protecting group

Ph phenyl

Ph₃P triphenyl phosphine

Prep Preparative

Rf ratio of fronts

RP reverse phase

Rt Retention time

rt Room temperature

SFC Supercritical Fluid Chromatography

Si0₂ Silica gel

T3P® Propylphosphonic acid anhydride

TBAF Tetrabutylammonium fluoride

TBDMS t-Butyldimethylsilyl

TEA Triethylamine

TFA Trifluoroacetic acid

THF Tetrahydrofuran

TLC Thin Layer Chromatography

TsCI toluene sulfonyl chloride

[00187] Within the scope of this text, a readily removable group that is not a constituent of the particular desired end product of the compounds of the present invention is designated a "protecting group," unless the context indicates otherwise. The protection of functional groups by such protecting groups, the protecting groups themselves, and their cleavage reactions are described for example in standard reference works, such as e.g., Science of Synthesis:

Houben-Weyl Methods of Molecular Transformation. Georg Thieme Verlag, Stuttgart, Germany. 2005. 41627 pp. (URL: http://www.science-of-synthesis.com (Electronic Version, 48 Volumes)); J. F. W. McOmie, "Protective Groups in Organic Chemistry", Plenum Press, London and New York 1973, in T. W. Greene and P. G. M. Wuts, "Protective Groups in Organic Synthesis", Third edition, Wiley, New York 1999, in "The Peptides"; Volume 3 (editors: E. Gross and J. Meienhofer), Academic Press, London and New York 1981 , in "Methoden der organischen Chemie" (Methods of Organic Chemistry), Houben Weyl, 4th edition, Volume 15/1, Georg Thieme Verlag, Stuttgart 1974, in H.-D. Jakubke and H. Jeschkeit, "Aminosauren, Peptide, Proteine" (Amino acids, Peptides, Proteins), Verlag Chemie, Weinheim, Deerfield Beach, and Basel 1982, and in Jochen Lehmann, "Chemie der Kohlenhydrate: Monosaccharide und Derivate" (Chemistry of Carbohydrates: Monosaccharides and Derivatives), Georg Thieme Verlag, Stuttgart 1974. A characteristic of protecting groups is that they can be removed readily (i.e., without the occurrence of undesired secondary reactions) for example by solvolysis, reduction, photolysis or alternatively under physiological conditions (e.g., by enzymatic cleavage).

[00188] Salts of compounds of the present invention having at least one salt-forming group may be prepared in a manner known per se. For example, salts of compounds of the present invention having acid groups may be formed, for example, by treating the compounds with metal compounds, such as alkali metal salts of suitable organic carboxylic acids, e.g., the sodium salt of 2-ethyl hexanoic acid, with organic alkali metal or alkaline earth metal compounds, such as the corresponding hydroxides, carbonates or hydrogen carbonates, such as sodium or potassium hydroxide, carbonate or hydrogen carbonate, with corresponding calcium compounds or with ammonia or a suitable organic amine, stoichiometric amounts or only a small excess of the salt-forming agent preferably being used. Acid addition salts of compounds of the present invention are obtained in customary manner, e.g., by treating the compounds with an acid or a suitable anion exchange reagent. Internal salts of compounds of the present invention containing acid and basic salt-forming groups, e.g., a free carboxy group and a free amino group, may be formed, e.g., by the neutralization of salts, such as acid addition salts, to the isoelectric point, e.g., with weak bases, or by treatment with ion exchangers.

[00189] Salts can be converted in customary manner into the free compounds; metal and ammonium salts can be converted, for example, by treatment with suitable acids, and acid addition salts, for example, by treatment with a suitable basic agent.

[00190] Mixtures of isomers obtainable according to the invention can be separated in a manner known per se into the individual isomers; diastereoisomers can be separated, for example, by partitioning between polyphasic solvent mixtures, recrystallization and/or chromatographic separation, for example over silica gel or by, e.g., medium pressure liquid chromatography over a reversed phase column, and racemates can be separated, for example, by the formation of salts with optically pure salt-forming reagents and separation of the mixture of diastereoisomers so obtainable, for example by means of fractional crystallization, or by chromatography over optically active column materials.

[00191] Intermediates and final products can be worked up and/or purified according to standard methods, e.g., using chromatographic methods, distribution methods, (re-) crystallization, and the like.

EXAMPLES

[00192] The invention is illustrated by the following examples, which should not be construed as limiting. The assays used to demonstrate the efficacy of compounds of Formula (I) in these assays are generally regarded as predictive of efficacy in subjects.

General Conditions:

[00193] Mass spectra were run on LC-MS systems using electrospray ionization. These were WATERS Acquity Single Quard Detector. [M+H]⁺ refers to mono-isotopic molecular weights.

[00194] NMR spectra were run on open access Varian 400 or Varian 500 NMR spectrometers. Spectra were measured at 298K and were referenced using the solvent peak. Chemical shifts for ¹ H NMR are reported in parts per million (ppm).

[00195] Mass spectra were run on LC-MS systems with one of the following conditions:

[00196] Waters Acquity UPLC-H class system equipped with SQD detector.

[00197] Column: ACQUITY UPLC HSS C18 (50^*2.1 ) mm, 1 .8u.

[00198] Column temperature: Ambient.

[00199] Mobile Phase: A) 0.1 % FA + 5mM Ammonium Acetate in Water.

B) 0.1 % FA in Acetonitrile.

[00200] Gradient: 5-5% solvent B in 0.40 min, 5-35% solvent B in 0.80 min, 35- 55%solvent B in 1 .2 min, 55-100%solvent B in 2.5 min.

[00201] Flow rate: 0.55mL/min.

[00202] Compounds were detected by a Waters Photodiode Array Detector.

[00203] Waters LCMS system equipped with ZQ 2000 detector.

[00204] Column: X-BRIDGE C18 (50^*4.6) mm, 3.5u.

[00205] Column temperature: Ambient.

[00206] Mobile Phase: A) 0.1 % NH₃ in Water.

B) 0.1 % NH₃ in Acetonitrile. [00207] Gradient: 5-95% solvent B in 5.00 min.

[00208] Flow rate: 1 .OmL min.

[00209] Compounds were detected by a Waters Photodiode Array Detector.

[00210] Waters ACQUITY UPLC system and equipped with a ZQ 2000 MS system

[00211] Column: Kinetex by Phenomenex, 2.6 urn, 2.1 x 50mm

[00212] Column temperature: 50 °C

[00213] Gradient: 2-88% (or 00-45%, or 65-95%) solvent B over a 1 .29 min period

[00214] Flow rate: 1 .2ml_/min.

[00215] Compounds were detected by a Waters Photodiode Array Detector.

[00216] Chiral separations were done with the following columns:

AD: ChiralPak AD-H, SFC 21 x250mm

OD: ChiralPak OD-H, SFC 21 x250mm

Example 1.1:

6-(tert-butyl)- 11, 12-dimethoxy-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3- carboxylic acid [1.1-1] and [1.1 -II]

1.1

Step 1: (4,5-dimethoxy-1H-indol-2-yl)methanol [1.1a]

1.1a

[00217] To 4,5-dimethoxy-1 H-indole-2-carboxylic acid (900 mg, 4.07 mmol) was added THF (Volume: 30 mL), cooled to about 0 °C then LAH 2M in THF (4.07 mL, 8.14 mmol) was added. The reaction was allowed to warm to room temperature and stirred at room temperature for 3 hours or until done by LCMS. The reaction was cooled in ice bath, then quenched carefully by adding excess water (2.0 ml), dropwise, stirred for 10 minutes then 350 ml of ethyl acetate was added. The organic layer was washed with minimal water 3x, saturated salt solution, dried sodium sulfate, filtered and concentrate to residue to give the desired product 1.1a assume in quantitative yield, used as is LC-MS (m/z): 208.2 [M+H]⁺, 0.39 min.

Step 2: 2-(((tert-butyldimethylsilyl)oxy)methyl)-4,5-dimethoxy-1H-indole [ 1.1b]

[00218] To 1.1a (775 mg, 3.74 mmol) was added DCM (Volume: 30 ml_), imidazole (815 mg, 1 1 .97 mmol) and stirred at room temperature for 5 minutes. Then TBDMSCI (1691 mg, 1 1 .22 mmol) was added and stirred at room temperature for 1 hour or until done by LCMS. To the reaction was added 200 ml of ethyl acetate washed with saturated sodium bicarbonate, water, saturated salt solution, dried sodium sulfate, filtered and concentrated to residue to give the desired product 1.1 b assume in quantitative yield, used as is. LC-MS (m/z): 322.3 [M+H]⁺, 0.94 min.

Step 3: 1 -(2-(((tert-butyldimethylsilyl)oxy)methyl) -4, 5-dimethoxy- 1 H-indol- 1 -yl) -3, 3- dimethylbutan-2-one [1.1c]

1.1c

[00219] To 1.1 b (1 180 mg, 3.67 mmol) was added DMF (Volume: 30 mL), cesium carbonate (3588 mg, 1 1 .01 mmol) and stirred for 15 minutes at 35-40 °C. Then 1 -bromo-3,3- dimethylbutan-2-one (1643 mg, 9.18 mmol) was added and stirred at 35-40 °C for 14 hours or until done by LCMS. To the reaction was added 200 ml of ethyl acetate washed with saturated sodium bicarbonate, water, saturated salt solution, dried sodium sulfate, filtered and concentrated to residue. The crude material was purified by silica gel column chromatography, using 0 to 40% EtOAc/heptanes. The desired fractions were concentrated to constant mass to give 1510 mg of the desired product 1.1 c in 98% yield. LC-MS (m/z): 420.4 [M+H]⁺, 1 .07 min.

Step 4: (1-(2-amino-3,3-dimethylbutyl)-4,5-dimethoxy-1H-indo [1.1d]

[00220] To 1.1 c (1510 mg, 3.60 mmol) was added MeOH (Volume: 1 1 ml_), ammonium acetate (4161 mg, 54.0 mmol) and sodium cyanoborohydride (678 mg, 10.80 mmol). The reaction was then stirred at 55 °C for 40 hours or until done by LCMS. To the crude reaction was added 350 ml of DCM and 25 ml of methanol, extracted with 1 :1 solution of (6 M NaOH, and saturated salt solution). The aqueous layer was back extracted with DCM. The organics were combined washed with saturated salt solution, dried with sodium sulfate, filtered through 1 cm x 2cm celite filter plug, washed with a solution of DCM with 10% methanol, concentrated to residue to give the desired product 1.1d assume in quantitative yield, used as is. LC-MS (m/z): 307.3 [M+H]⁺, 0.59 min.

Step 5: 3-(tert-butyl)-8,9-dimethoxy-3,4-dihydropyrazino[ 1,2-a]indole [ 1.1e]

[00221] To 1.1 d (1 100 mg, 3.59 mmol) was added DCM (Volume: 18 ml_), and manganese dioxide (3121 mg, 35.9 mmol). The reaction was then stirred room temperature for 2 hours. Then additional manganese dioxide (1561 mg, 17.95 mmol) was added and stirred overnight for total of 20 hours or until done by LCMS. Additional manganese dioxide can be added if needed. To the crude was added 60 ml of DCM stirred for 30 minutes then filtered through 1 cm x 2 cm celite filter plug, flushed with DCM and concentrated to residue. The residue was dissolved in 5 ml of DCM, excess TFA (0.830 mL, 10.77 mmol) was added, stirred for 5 minutes at room temperature and then concentrated to residue to give the desired product 1.1e assume in quantitative yield, used as is. LC-MS (m/z): 287.2 [M+H]⁺, 0.69 min.

Step 6: ethyl 6-(tert-butyl)-11, 12-dimethoxy-2-oxo-2,6,7, 13b-tetrahydro-1H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylate [1.1f]

1.If

[00222] To 1.1e (1400 mg, 3.50 mmol) was added Ethanol (Volume: 12 ml_), and (Z)- ethyl 2-(ethoxymethylene)-3-oxobutanoate (1953 mg, 10.49 mmol). The reaction was then stirred at 90-95 °C for 24 hours or until done by LCMS. The reaction was concentrated to residue to give the desired product 1.1f assume in quantitative yield, used as is. LC-MS (m/z): 427.4 [M+H]⁺, 0.89 min.

Step 7: ethyl 6-(tert-butyl)-11, 12-dimethoxy-2-oxo-6,7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[1 ,2- a]indole-3-carboxylate [ 1.1g-l] and [1.1g-ll]

1.1 g-l ^and 1.1g-ll

[00223] To 1.1f (1490 mg, 3.49 mmol) was added DME (Volume: 15 mL), and then chloranil (859 mg, 3.49 mmol). The reaction was stirred at 90-95 °C for 90 minutes or until done by LCMS. The solvent was concentrated off to residue. The crude material was purified by silica gel column chromatography, using 0 to 90% EtOAc(with 20% ethanol)/heptanes. The desired fractions were concentrated to constant mass to give 580 mg of the desired racemic product 1.1 g in 39% yield. LC-MS (m/z): 425.4 [M+H]⁺, 0.83 min.; ¹H NMR (DMSO-d₆) δ: 8.43 (s, 1 H), 7.41 (d, J=9.1 Hz, 1 H), 7.31 (s, 1 H), 7.12 (d, J=9.1 Hz, 1 H), 6.97 (s, 1 H), 4.90 (d, J=13.9 Hz, 1 H), 4.57 (d, J=4.7 Hz, 1 H), 4.38 (dd, J=14.2, 4.7 Hz, 1 H), 4.23 (q, J=7.1 Hz, 2H), 3.96 (s, 3H), 3.82 (s, 3H), 1 .28 (t, J=7.1 Hz, 3H), 0.73 (s, 9H) [00224] The above racemic material 562 mg was separated by chiral chromatography using (OD column, SFC=1 00ml_/min, CO₂/EtOH=70/30, 276bar) to give products 1.1 g-l (peak 1 , tR 3.12 min.) at 1 96 mg and product 1.1 g-ll (peak 2, tR 7.26 min.) at 1 92 mg.

Step 8: 6-(tert-butyl)-11, 12-dimethoxy-2-oxo-6,7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[1 ,2- a]indole-3-carboxylic acid [1.1-1] and [ 1.1-11]

1 .1 -1 and 1 .1 -11

[00225] To 1.1 g-l (1 95 mg, 0.459 mmol) was added THF (Volume: 1 ml_, Ratio: 1 .000), MeOH (Volume: 1 ml_, Ratio: 1 .000) and then NaOH 3M aq (0.459 ml_, 1 .378 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 5 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 148.5 mg of the desired product 1.1 -1 as TFA salt in 62% yield. LC-MS (m/z) : 397.3 [M+H]⁺, 0.85 min.; ¹ H NMR (DMSO-d₆) δ: 8.85 (s, 1 H), 7.55 (s, 1 H), 7.50 (s, 1 H), 7.45 (d, J=8.8 Hz, 1 H) , 7.1 8 (d, J=9.1 Hz, 1 H), 4.98 (d, J=13.9 Hz, 1 H), 4.84 (d, J=4.4 Hz, 1 H), 4.45 (dd, J=14.2, 4.7 Hz, 1 H), 3.98 (s, 3H), 3.83 (s, 3H), 0.73 (s, 9H) .

[00226] To 1.1 g-ll (96 mg, 0.226 mmol) was added THF (Volume: 1 ml_, Ratio: 1 .000), MeOH (Volume: 1 ml_, Ratio: 1 .000) and then NaOH 3M aq (0.226 ml_, 0.678 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 3 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 71 .1 mg of the desired product 1.1 -11 as the TFA salt in 60% yield. LC-MS (m/z) : 397.4 [M+H]⁺, 0.85 min.; ¹ H NMR (DMSO-d₆) δ: 8.85 (s, 1 H), 7.55 (s, 1 H), 7.50 (s, 1 H), 7.45 (d, J=8.8 Hz, 1 H), 7.1 8 (d, J=8.8 Hz, 1 H), 4.98 (d, J=13.9 Hz, 1 H), 4.84 (d, J=4.4 Hz, 1 H), 4.45 (dd, J=14.0, 4.9 Hz, 1 H), 3.98 (s, 3H), 3.83 (s, 3H) , 0.73 (s, 9H)

Example 1.2:

6-(tert-butyl)- 12-(difluoromethoxy)- 11 -methoxy-2-oxo-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[1,2-a]indole-3-carboxylic acid [1.2-1] and [1.2-11]

1.2-1 and 1.2-11

Step 1 to 7: ethyl 6-(tert-butyl)-12-(difluoromethoxy)-11-methoxy-2-oxo-6,7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylate [1.2g-l] and [1.2g-ll]

1.2g-l ^and 1.2g-ll

[00227] Compound 1.2g was synthesized from the starting material; 4- (difluoromethoxy)-5-methoxy-1 H-indole-2-carboxylic acid by the process of Example 1.1 following steps 1 through 7 resulting in the desired product 1.2g as a racemate. LC-MS (m/z): 461 .3 [M+H]⁺, 0.90 min.

[00228] The above racemic material (300 mg) was separated by chiral chromatography using (OD column, SFC=100ml/min, C0₂/MeOH=85/15, 236bar) to give products 1.2g-l (peak 1 , tR 5.76 min.) at 84 mg and product 1.2g-ll (peak 2, tR 1 1 .98 min.) at 88 mg.

Step 8: 6-(tert-butyl)-12-(difluoromethoxy)-11-methoxy-2-oxo-6,7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2- d [ 1.2-11]

1.2-1 and 1.2-11

[00229] To 1.2g-l (84 mg, 0.182 mmol) was added THF (Volume: 0.2 ml_, Ratio: 1 .000), MeOH (Volume: 0.2 ml_, Ratio: 1 .000) and then NaOH 3M aq (0.182 ml_, 0.547 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 4 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 59.7 mg of the desired product 1.2-1 as TFA salt in 60% yield. LC-MS (m/z): 433.2 [M+H]⁺, 1 .03 min.; ¹H NMR (<dmso>) δ: 8.84 (s, 1 H), 7.71 (d, J=9.0 Hz, 1 H), 7.52 (s, 1 H), 7.42 (s, 1 H), 7.29 (d, J=9.0 Hz, 1 H), 6.85-7.26 (m, 1 H), 5.02 (d, J=14.1 Hz, 1 H), 4.83 (d, J=4.5 Hz, 1 H), 4.47 (dd, J=14.1 , 4.8 Hz, 1 H), 3.86 (s, 3H), 0.70 (s, 9H

[00230] To 1.2g-ll (84 mg, 0.182 mmol) was added THF (Volume: 1 ml_, Ratio: 1 .000), MeOH (Volume: 1 ml_, Ratio: 1 .000) and then NaOH 3M aq (0.182 ml_, 0.547 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 4 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 60.6 mg of the desired product 1.2-II as TFA salt in 61 % yield. 433.2 [M+H]⁺, 1 .03 min.; ¹H NMR (<dmso>) δ: 8.84 (s, 1 H), 7.71 (d, J=9.0 Hz, 1 H), 7.52 (s, 1 H), 7.42 (s, 1 H), 7.29 (d, J=9.1 Hz, 1 H), 6.87-7.27 (m, 1 H), 5.02 (d, J=14.1 Hz, 1 H), 4.83 (d, J=4.5 Hz, 1 H), 4.47 (dd, J=14.1 , 4.7 Hz, 1 H), 3.86 (s, 3H), 0.70 (s, 9H)

Example 1.3:

6-(tert-butyl)- 12-methoxy-2-oxo-6, 7-dihydro-2H-pyrido[ 1,2-a]pyrido[3',2':4,5]pyrrolo[2, 1- c]pyrazine-3-carboxylic acid [ 1.3-1] and [ 1.3-11]

1.3-1 and 1.3-11

Step 1 to 7: ethyl 6-(tert-butyl)-12-methoxy-2-oxo-6,7-dihydro-2H-pyrido[1,2- a]pyrido[3',2':4,5]pyrrolo[2, 1 -c]pyrazine-3-carboxylate [ 1.3g-l] and [ 1.3g-ll]

1.3g-l ^and 1.3g-ll

[00231] Compound 1.3g was synthesized from the starting material; methyl 4-methoxy- 1 H-pyrrolo[2,3-b]pyridine-2-carboxylate by the process of Example 1.1 following steps 1 through 7 resulting in the desired product 1.3g as a racemate. LC-MS (m/z): 396.3 [M+H]⁺,

0.70 min.

[00232] The above racemic material (398 mg) was separated by chiral chromatography using (AD column, SFC=100ml/min, C02/MeOH=75/25, 256bar) to give products 1.3g-l (peak

1 , tR 2.79 min.) at 95 mg and product 1.3g-ll (peak 2, tR 5.88 min.) at 90 mg.

Step 8: 6-(tert-butyl)- 12-methoxy-2-oxo-6, 7-dihydro-2H-pyrido[ 1,2-a]pyrido[3',2':4,5]pyrrolo[2, 1 - c]pyrazine-3-carboxylic acid [1.3-1] and [1.3-11]

1.3-1 and 1.3-11

[00233] To 1.3g-l (16 mg, 0.040 mmol) was added THF (Volume: 0.2 ml_, Ratio: 1 .000), MeOH (Volume: 0.2 ml_, Ratio: 1 .000) and then NaOH 3M aq (0.040 ml_, 0.121 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 1 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 7.3 mg of the desired product 1.3-1 as TFA salt in 37% yield. LC-MS (m/z): 368.2 [M+H]+, 0.86 min.; ¹H NMR (<dmso>) δ: 8.87 (s, 1 H), 8.30 (d, J=5.5 Hz, 1 H), 7.52 (d, J=0.9 Hz, 2H), 6.80 (d, J=5.5 Hz, 1 H), 5.04 (d, J=14.1 Hz, 1 H), 4.84 (d, J=4.5 Hz, 1 H), 4.46 (dd, J=14.2, 4.8 Hz, 1 H), 3.99 (s, 3H), 0.68 (s, 9H)

[00234] To 1.3g-ll (16 mg, 0.040 mmol) was added THF (Volume: 0.2 ml_, Ratio: 1 .000), MeOH (Volume: 0.2 ml_, Ratio: 1 .000) and then NaOH 3M aq (0.040 ml_, 0.121 mmol). The reaction was stirred at room temperature for 2 hours or untill done by LCMS. The solvent was concentrated off, the residue was dissolved in 1 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 7.3 mg of the desired product 1.3-11 as TFA salt in 37% yield. LC-MS (m/z): 368.2 [M+H]+, 0.86 min.; ¹H NMR (<dmso>) δ: 8.87 (s, 1 H), 8.30 (d, J=5.5 Hz, 1 H), 7.52 (d, J=0.9 Hz, 2H), 6.80 (d, J=5.6 Hz, 1 H), 5.04 (d, J=14.1 Hz, 1 H), 4.84 (d, J=4.5 Hz, 1 H), 4.46 (br dd, J=14.2, 4.8 Hz, 1 H), 4.00 (s, 3H), 0.68 (s, 9H)

Example 1.4: 6-(tert-butyl)- 12-hydroxy-2-oxo-6, 7-dihydro-2H-pyrido[ 1,2-a]pyrido[3',2':4,5]pyrrolo[2, 1- c]pyrazine-3-carboxylic acid [1.4]

1.4

[00235] To 1.3g (16 mg, 0.040 mmol) was added DMF (Volume: 0.6 mL) and then sodium thiomethoxide (1 1 .34 mg, 0.162 mmol). The reaction was stirred and heated to 75 °C for 1 hour. Then additional sodium thiomethoxide (1 1 .34 mg, 0.162 mmol) was added and the reaction was heated at 95 °C for 90 minutes, followed by LCMS. The reaction was let cool, dissolved in 0.6 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 6.0 mg of the desired racemic product 1.4 as the TFA salt in 31 % yield. LC-MS (m/z): 354.2 [M+H]+, 0.64min.; ¹ H NMR (<dmso>) δ: 8.86 (s, 1 H), 8.13 (d, J=5.5 Hz, 1 H), 7.46 (d, J=9.4 Hz, 2H), 6.57 (d, J=5.5 Hz, 1 H), 5.02 (d, J=14.0 Hz, 1 H), 4.82 (d, J=4.5 Hz, 1 H), 4.43 (dd, J=14.1 , 4.8 Hz, 1 H), 0.69 (s, 9H)

Example 1.5:

6-(tert-butyl)- 12-hydroxy-2-oxo-6, 7-dihydro-2H-pyrido[ 1,2-a]pyrido[3',2':4,5]pyrrolo[2, 1- c]pyrazine-3-carboxylic acid [1.5-1] and [1.5-11]

1.5-1 and 1.5-11

[00236] To 1.3g-l (38 mg, 0.096 mmol) was added DMF (Volume: 1 mL) and SODIUM THIOMETHOXIDE (33.7 mg, 0.480 mmol). The reaction was heated at 95 °C-100 °C for 2 hours, followed by LCMS. Then additional SODIUM THIOMETHOXIDE (33.7 mg, 0.480 mmol) was added and heated at 95 °C for additional 2 hours or until done by LCMS. The reaction was let cool. To the crude reaction was added 2.0 ml of DMSO with 5% water, purified by reverse phase prep LC and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 23 mg of the desired product 1.5-1 as TFA salt in 51 % yield. LC-MS (m/z): 354.5 [M+H]+, 0.63 min.; ¹ H NMR (<dmso>) δ: 8.86 (s, 1 H), 8.14 (d, J=5.6 Hz, 1 H), 7.47 (d, J=1 1 .9 Hz, 2H), 6.59 (d, J=5.6 Hz, 1 H), 5.03 (d, J=14.1 Hz, 1 H), 4.82 (br d, J=4.4 Hz, 1 H), 4.43 (br dd, J=14.1 , 4.7 Hz, 2H), 0.69 (s, 9H)

[00237] To 1.3g-ll (38 mg, 0.096 mmol) was added DMF (Volume: 1 mL) and SODIUM THIOMETHOXIDE (33.7 mg, 0.480 mmol). The reaction was heated at 95 °C-1 00 °C for 2 hours, followed by LCMS. Then additional SODIUM THIOMETHOXIDE (33.7 mg, 0.480 mmol) was added and heated at 95 °C for additional 2 hours or until done by LCMS. The reaction was let cool. To the crude reaction was added 2.0 ml of DMSO with 5% water, purified by reverse phase prep LC and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 33 mg of the desired product 1.5-11 as TFA salt in 73% yield. LC-MS (m/z): 354.3 [M+H]+, 0.56 min.; 1 H NMR (<dmso>) δ: 8.86 (s, 1 H), 8.13 (d, J=5.6 Hz, 1 H), 7.48 (s, 1 H), 7.45 (s, 1 H), 6.58 (d, J=5.5 Hz, 1 H), 5.02 (d, J=14.0 Hz, 1 H), 4.82 (d, J=4.5 Hz, 1 H), 4.43 (br dd, J=14.1 , 4.7 Hz, 1 H), 0.69 (s, 9H)

Example 1.6:

6-(tert-butyl)- 12-(difluoromethoxy)-2-oxo-6, 7-dihydro-2H-pyrido[ 1,2- a]pyrido[3',2':4,5]pyrrolo[2, 1- 1] and [1.6-11]

1.6-1 and 1.6-11

[00238] To 1.5-1 (20 mg, 0.057 mmol) was added DMF (Volume: 1 .5 mL) and potassium carbonate (39.1 mg, 0.283 mmol) and stirred at room temperature for 25 minutes. Then ethyl 2-bromo-2,2-difluoroacetate (92 mg, 0.453 mmol) was added and stirred at 40 °C for 2 hours or until done by LCMS. To the reaction was added 1 ml of methanol and 0.2 ml of water and stirred for 1 hour at room temperature. The reaction was concentrated to remove some of the methanol, additional 1 .5 ml of DMF was added, purified by reverse phase prep LC, with the desired peak collected and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 3.3 mg of the desired product 1.6-1 as TFA salt in 1 1 % yield. LC-MS (m/z): 404.5 [M+H]+, 0.84 min. ; 1 H NMR (<dmso>) δ: 8.91 (s, 1 H), 8.42 (d, J=5.4 Hz, 1 H), 7.61 (d, J=8.5 Hz, 2H), 7.46-7.85 (m, 1 H), 7.03 (d, J=5.4 Hz, 1 H), 5.08 (br d, J=14.1 Hz, 1 H), 4.88 (br d, J=4.5 Hz, 1 H), 4.51 (br dd, J=14.1 , 4.7 Hz, 1 H), 0.69 (s, 9H) [00239] To 1.5-11 (25 mg, 0.071 mmol) was added DMF (Volume: 1 .5 mL) and potassium carbonate (48.9 mg, 0.354 mmol) and stirred at room temperature for 25 minutes. Then ethyl 2-bromo-2,2-difluoroacetate (1 1 5 mg, 0.566 mmol) was added and stirred at 40 °C for 4 hours or until done by LCMS. To the reaction was added 1 ml of methanol and 0.2 ml of water and stirred for 1 hour at room temperature. The reaction was concentrated to remove some of the methanol, additional 1 .5 ml of DMF was added, purified by reverse phase prep LC, with desired peak collected and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 3.3 mg of the desired product 1.6-11 as TFA salt in 9% yield. LC-MS (m/z) : 404.5 [M+H]+, 0.88 min.; 1 H NMR (<dmso>) δ: 8.91 (s, 1 H), 8.42 (d, J=5.4 Hz, 1 H), 7.61 (d, J=8.6 Hz, 2H), 7.45-7.87 (m, 1 H), 7.03 (br d, J=5.3 Hz, 1 H), 5.08 (br d, J=14.1 Hz, 1 H), 4.88 (br d, J=4.1 Hz, 1 H), 4.51 (br dd, J=14.1 , 4.5 Hz, 1 H), 0.69 (s, 9H)

Example 1.7:

6-(tert-butyl)-13-fluoro-11, 12-dimethoxy-2-oxo-6,7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[1 ,2- a ]indole-3-carboxylic acid [1.7-1] and [1.7-11]

1.7-1 and 1.7-11

Step 1 : ethyl 6-(tert-butyl)- 13-fluoro- 11, 12-dimethoxy-2-oxo-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylate [1.7a]

[00240] To 1.1 g (475 mg, 1 .1 1 9 mmol) was added DCM (Volume: 1 6 mL), cooled in ice bath and then with stirring SELECTFLUOR (396 mg, 1 .1 1 9 mmol) was added. The reaction was allowed to warm to room temperature and stirred for 2 hours or until done by LCMS. To the reaction was added 1 6 ml of DCM, filtered through a 0.5 cm x 2 cm silica pad, flushed with 30 ml of DCM, then 30 ml solution of (DCM with 15% ethanol). The solvent was concentrated off to crude residue, dissolved in 6 ml of DMSO, purified by reverse phase prep LC to give the desired product 1.7a as a solution in 1 50 ml of 1 :1 ACN/water solution with 0.1 % TFA, assume 1 5% yield, used as is. LC-MS (m/z) : 443.2 [M+H]+, 0.92 min.

Step 2: 6-(tert-butyl)-13-fluoro- 11, 12-dimethoxy-2-oxo-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylic acid [ 1.7-1] and [ 1.7-11]

1.7-1 and 1.7-11

[00241] To 1.7a (75 mg, 0.135 mmol) that was already in a solution of Acetonitrile

(Volume: 75 ml_, Ratio: 1 .000), Water (Volume: 75 ml_, Ratio: 1 .000) with 0.1 % TFA, was added NaOH 3M aq (0.898 ml_, 2.70 mmol) until the pH was 13 or greater. The reaction was stirred at room temperature for 2 hours or until done by LCMS. The reaction was neutralized with TFA to give pH of 3-4 and lyophilized to residue. The crude residue was dissolved in 3 ml of DMSO with 5% water, purified by reverse phase prep LC and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 1 2.5 mg of the desired racemic product 1.7 as TFA salt in 1 7% yield. LC-MS (m/z): 415.3 [M+H]+, 0.86 min.; 1 H NMR (DMSO) δ: 8.87 (s, 1 H), 7.53 (d, J=9.2 Hz, 1 H), 7.28 (d, J=8.9 Hz, 1 H), 7.06 (s, 1 H), 5.02 (br d, J=14.0 Hz, 1 H), 4.84 (d, J=4.3 Hz, 1 H), 4.40 (dd, J=14.0, 4.6 Hz, 1 H), 3.92 (s, 3H), 3.85 (s, 3H), 0.75 (s, 9H)

[00242] The above racemic material (1 2.5 mg) was dissolved in methanol with 1 0Oul of DEA added and was separated by chiral chromatography using (AD Column, SFC=80ml/min, C02/EtOH=85/15, 256bar) to give products 1.7-1 (peak 1 , tR 7.84 min.) at 2.2 mg and product 1.7-11 (peak 2, tR 1 0.33 min.) at 3.4 mg.

[00243] 1.7-1 LC-MS (m/z): 415.3 [M+H]+, 0.90 min.; 1 H NMR (<dmso>) δ: 8.74 (br s, 1 H), 7.47 (br d, J=8.9 Hz, 1 H), 7.22 (br d, J=9.0 Hz, 1 H), 6.96 (br s, 1 H) , 4.95 (br d, J=13.8 Hz, 1 H), 4.74 (br s, 1 H), 4.33 (br d, J=10.2 Hz, 1 H), 3.86 (s, 3H), 3.79 (s, 3H), 0.69 (s, 9H)

[00244] 1.7-11 LC-MS (m/z) : 41 5.3 [M+H]+, 0.90 min.; 1 H NMR (DMSO-d6) δ: 8.58 (br s, 1 H), 7.50 (br d, J=8.9 Hz, 1 H), 7.23 (br d, J=9.0 Hz, 1 H), 6.84 (br s, 1 H), 4.96 (br d, J=13.7 Hz, 1 H), 4.66 (br s, 1 H), 4.33 (br d, J=10.5 Hz, 1 H) , 3.90 (s, 3H), 3.84 (s, 3H), 0.74 (s, 9H) Example 1.8:

6-(ten-butyl)-11-fluoro-2-oxo-6 -dihydro-2H-pyrido^

3-carboxylic acid [ 1.8-1] and [ 1.8-11]

1.8-1 and 1.8-11

Step 1 to 7: ethyl 6-(tert-butyl)-11-fluoro-2-oxo-6,7-dihydro-2H-pyrido[1,2- a]pyrido[3',2':4,5]pyrrolo[2, 1 -c]pyrazine-3-carboxylate [ 1.8g-l] and [ 1.8g-ll]

1.8g-l ^and 1.8g-ll

[00245] Compound 1.8g was synthesized from the starting material; 5-fluoro-1 H- pyrrolo[2,3-b]pyridine-2-carboxylic acid by the process of Example 1.1 following steps 1 through 7 resulting in the desired product 1.8g as a racemate. LC-MS (m/z): 384.5 [M+H]⁺, 0.82 min. 1 H NMR (<dmso>) δ: 8.48 (s, 1 H), 8.35-8.41 (m, 1 H), 8.01 (dd, J=9.3, 2.7 Hz, 1 H), 7.29 (s, 1 H), 7.04 (s, 1 H), 5.01 (d, J=14.0 Hz, 1 H), 4.62 (d, J=4.5 Hz, 1 H), 4.44 (dd, J=14.0, 4.8 Hz, 1 H), 4.21 (q, J=7.1 Hz, 2H), 1 .26 (t, J=7.1 Hz, 3H), 0.68 (s, 9H)

[00246] The above racemic material (740 mg) was separated by chiral chromatography using (AD column, SFC=100ml/min, CO2/EtOH=80/20, 216bar) to give products 1.8g-l (peak 1 , tR 5.25 min.) at 230 mg and product 1.8g-ll (peak 2, tR 8.17 min.) at 282 mg.

Step 8: 6-(tert-butyl)-11-fluoro-2-oxo-6 -dihydro-2H-pyrido[1,2-a]pyrido[3',2':4,5]pyrrolo[2, 1- c]pyrazine-3-carboxylic acid [ 1.8-1] and [ 1.8-11]

1.8-1 and 1.8-11

[00247] To 1.8g-l (20 mg, 0.052 mmol) was added DMF (Volume: 1 mL) and LiOH 1 M aq (0.209 mL, 0.209 mmol). The reaction was stirred at room temperature for 30 minutes or until done by LCMS. Additional LiOH 1 M aq. can be added if needed. The reaction was purified by reverse phase prep LC, and lyophilized to give 13.5 mg of the desired product 1.8-1 as the TFA salt in 54% yield. LC-MS (m/z) : 356.3 [M+H]⁺, 0.81 min. ; 1 H NMR (<dmso>) δ: 8.92 (s, 1 H), 8.42-8.48 (m, 1 H), 8.08 (dd, J=9.2, 2.7 Hz, 1 H), 7.57 (s, 1 H), 7.49 (s, 1 H), 5.06 (d, J=14.1 Hz, 1 H), 4.88 (d, J=4.5 Hz, 1 H), 4.50 (dd, J=14.2, 4.9 Hz, 1 H), 0.69 (s, 9H)

[00248] To 1.8g-ll (18 mg, 0.047 mmol) was added DMF (Volume: 1 mL) and LiOH 1 M aq (0.1 88 mL, 0.1 88 mmol). The reaction was stirred at room temperature for 30 minutes or until done by LCMS. Additional LiOH 1 M aq. can be added if needed. The reaction was purified by reverse phase prep LC, and lyophilized to give 9.2 mg of the desired product 1.8-11 as the TFA salt in 41 % yield. LC-MS (m/z) : 356.3 [M+H]⁺, 0.81 min. ; 1 H NMR (<dmso>) δ: 8.92 (s, 1 H), 8.42-8.49 (m, 1 H), 8.08 (dd, J=9.2, 2.7 Hz, 1 H), 7.57 (s, 1 H), 7.49 (s, 1 H), 5.06 (d, J=14.1 Hz, 1 H), 4.88 (d, J=4.5 Hz, 1 H), 4.50 (dd, J=14.2, 4.8 Hz, 1 H), 0.69 (s, 9H).

Example 1.9:

6-(tert-butyl)- 1 1, 13-difluoro-2-oxo-6, 7-dihydro-2H-pyrido[ 1,2-a]pyrido[3',2':4,5]pyrrolo[2, 1- c]pyrazine-3-carboxylic acid [ 1.9-1] and [ 1.9-11]

1.9-1 and 1.9-11

Step 1: ethyl 6-(tert-butyl)- 11, 13-difluoro-2-oxo-6,7-dihydro-2H-pyrido[1,2- a]pyrido[3',2':4,5]pyrrolo[2, 1 -c]pyrazine-3-carboxylate [ 1.9a-l] and [ 1.9a-ll]

1.9a-l and 1.9a-ll

[00249] To 1.8g (400 mg, 1 .043 mmol) was added acetonitrile (Volume: 35 ml_), sodium bicarbonate (2.087 ml_, 2.087 mmol) and cooled in ice bath. While in the ice bath

SELECTFLUOR (517 mg, 1 .461 mmol) was added and stirred for 5 minutes. Then the reaction was allowed to warm to room temperature with stirring for 6 hours or until done by LCMS. The reaction was diluted with 300 ml of ethyl acetate, washed with saturated sodium bicarbonate, water, saturated salt solution, dried with sodium sulfate, filtered and concentrated to residue. The crude material was purified by silica gel chromatography using 0 to 70% (ethyl acetate with 25% ethanol) and heptane, the desired fractions were concentrated to residue. The crude product was dissolved in 4 ml of DMSO with 5% water, purified by reverse phase prep LC, the desired fractions were combined and lyophilized. The product was re-dissolved in ACN/water and lyophilized to give 175 mg of the desired racemic product 1.9a as TFA salt in 33 %yield. LC-MS (m/z): 402.4 [M+H]⁺, 0.83 min.; 1 H NMR (<dmso>) δ: 8.52 (s, 1 H), 8.48-8.51 (m, 1 H), 8.19 (dd, J=8.7, 2.6 Hz, 1 H), 6.76 (s, 1 H), 5.06 (br d, J=14.0 Hz, 1 H), 4.64 (br d, J=4.4 Hz, 1 H), 4.41 (br dd, J=14.0, 4.7 Hz, 1 H), 4.22 (q, J=7.1 Hz, 2H), 1 .26 (t, J=7.1 Hz, 3H), 0.71 (s, 9H)

[00250] The above racemic material (160 mg) was separated by chiral chromatography using (AS column, SFC=100ml/min, CO2/EtOH=80/20, 216bar) to give products 1.9a-l (peak 1 , tR 2.46 min.) at 54 mg and product 1.9a-ll (peak 2, tR 6.34 min.) at 56 mg.

Step 2: 6-(tert-butyl)- 11, 13-difluoro-2-oxo-6, 7-dihydro-2H-pyrido[ 1,2- a]pyrido[3',2':4,5]pyrrolo[2, 1 -c]pyrazine-3-carboxylic acid [1.9-1] and [1.9-11]

1.9-1 and 1.9-11

[00251] To 1.9a-l (54 mg, 0.135 mmol) was added ACN (Volume: 2 mL, Ratio: 1 .000), Water (Volume: 2, Ratio: 1 .000) and then LiOH 1 M aq (0.538 mL, 0.538 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The reaction was diluted with 1 0 ml of water acidified with 1 M HCI to pH of 2-3, then 80 ml of DCM with 3% ethanol was added and 10 ml of saturated sodium chloride solution. The organic layer was separated, the aqueous layer was extracted again 1 x 40 ml DCM with 2% ethanol. The organic layers were combined, washed with water (3x), filtered and concentrated to residue. The residue was dissolved in 1 :1 ACN/water, filtered and lyophilized to give 46.2 mg of the desired product 1.9-1 as the free base in 90% yield. LC-MS (m/z) : 374.4 [M+H]⁺, 0.86 min.; 1 H NMR (<dmso>) δ: 8.92 (s, 1 H), 8.55 (t, J=2.0 Hz, 1 H), 8.24 (dd, J=8.6, 2.6 Hz, 1 H), 7.13 (s, 1 H), 5.1 1 (br d, J=14.1 Hz, 1 H), 4.87 (d, J=4.4 Hz, 1 H), 4.46 (dd, J=14.1 , 4.6 Hz, 1 H), 0.71 (s, 9H)

[00252] To 1.9a-ll (54 mg, 0.135 mmol) was added ACN (Volume: 2 ml_, Ratio: 1 .000), Water (Volume: 2, Ratio: 1 .000) and then LiOH 1 M aq (0.538 ml_, 0.538 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The reaction was diluted with 1 0 ml of water acidified with 1 M HCI to pH of 2-3, then 80 ml of DCM with 3% ethanol was added and 1 0 ml of saturated sodium chloride solution. The organic layer was separated, the aqueous layer was extracted again 1 x 40 ml DCM with 2% ethanol. The organic layers were combined, washed with water (3x), filtered and concentrated to residue. The residue was dissolved in 1 :1 ACN/water, filtered and lyophilized to give 46.4 mg of the desired product 1.9-11 as the free base, in 91 % yield. LC-MS (m/z): 374.4 [M+H]⁺, 0.86 min.; 1 H NMR (<dmso>) δ: 8.94 (s, 1 H), 8.55 (t, J=2.1 Hz, 1 H), 8.24 (dd, J=8.6, 2.6 Hz, 1 H), 7.14 (s, 1 H), 5.1 1 (d, J=14.1 Hz, 1 H), 4.88 (d, J=4.4 Hz, 1 H), 4.46 (dd, J=14.1 , 4.6 Hz, 1 H), 0.71 (s, 9H)

Example 1.10:

6-(tert-butyl)-1-fluoro-11, 12-dimethoxy-2-oxo-6,7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[1 ,2- a]indole-3-carboxylic acid [1.10-1] and [1.10-11]

1.10-1 and 1.10-11

Step 1: (Z)-ethyl 2-(ethoxymethylene)-4,4-difluoro-3-((trimethylsilyl)oxy)but-3-enoate [1.10a]

1.10a

[00253] Under an argon atmosphere, a mixture of Mg (0.810 g, 33.3 mmol)) and TMSCI (4.26 mL, 33.3 mmol) was initially sonicated for 15-20 minutes. Then to this mixture was added 3 ml of dry DMF. Then a solution of (Z)-ethyl 2-(ethoxymethylene)-4,4,4-trifluoro-3- oxobutanoate (1 .00 g, 4.16 mmol) in dry DMF (Volume: 6 mL, Ratio: 2.000) was added dropwise over 5-6 minutes at 50 °C under an argon atmosphere. The reaction mixture was stirred for additional 10 minutes at 50 °C. Some of the excess TMSCI was briefly removed under reduce pressure. The crude mixture was then filtered through a disposable filter funnel with polyethylene frit. The resulting DMF solution with the desire product was used for the next step without purification, assume about 90% yield, used as is.

Step 2: ethyl 6-(tert-butyl)-1-fluoro- 11, 12-dimethoxy-2-oxo-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylate [ 1.10b]

[00254] To zinc iodide (334 mg, 1 .048 mmol) and 1.1e (300 mg, 1 .048 mmol) was added dry Acetonitrile (Volume: 3 mL). To this suspension was added dropwise 1.10a (1079 mg, 3.67 mmol) from previous step, that is already in a solution of DMF (Volume: 9 mL, Ratio: 3.00) at 50 °C, over 6 to 8 minutes with heat given off on the addition. The reaction is stirred at 50 °C for 18 hours or until done by LCMS. The reaction was let cool, then was poured into 20 ml of a 10% HCI aq. Solution, stirred for 10-15 minutes, then extracted with dichloromethane (2x). The organic layers were combined and washed with saturated salt solution, dried over sodium sulfate, concentration to residue. The crude material was purified by silica gel chromatography, using 0-80% (ethyl acetate with 20% ethanol) and heptane, the desired fractions were concentrated to constant mass to give 375 mg of the desired product 1.10b in 81 % yield used as is. LC-MS (m/z): 443.4 [M+H]+, 0.86 min.; 1 H NMR (<dmso>) δ: 8.50 (s, 1 H), 7.45 (d, J=8.9 Hz, 1 H), 7.16 (d, J=8.9 Hz, 1 H), 7.07 (d, J=3.9 Hz, 1 H), 4.94 (d, J=13.9 Hz, 1 H), 4.70 (br d, J=4.4 Hz, 1 H), 4.41 (dd, J=14.0, 4.6 Hz, 1 H), 4.24 (q, J=7.0 Hz, 2H), 3.93 (s, 3H), 3.81 (s, 3H), 1 .27 (t, J=7.1 Hz, 3H), 0.69 (s, 9H)

Step 3: 6-(tert-butyl)- 1 -fluoro- 11, 12-dimethoxy-2-oxo-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[1,2-a]in and[1.10-11]

1.10-1 and 1.10-11

[00255] To 1.10b (31 7 mg, 0.71 6 mmol) was added THF (Volume: 2.5 mL, Ratio:

1 .000), MeOH (Volume: 2.5 mL, Ratio: 1 .000) and then NaOH 3M aq (0.71 6 mL, 2.149 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off to leave a residue, then 20 ml of water was added, acidified with 1 M HCI to pH about 2-3 extract with 1 25 ml of DCM, then 75 ml of DCM 2x, dried with sodium sulfate, filter and concentrate to residue to give 279 mg of desired racemic product 1.10 in 94% yield. LC-MS (m/z) : 415.4 [M+H]+, 0.89 min. ;

[00256] The above racemic material (279 mg) was dissolved in methanol with 400ul of DEA added and was separated by chiral chromatography using (AD Column, SFC=100ml/min, C02/IPA=75/25, 256bar) to give products 1.10-1 (peak 1 , tR 3.09 min.) at 65 mg and product 1.10-11 (peak 2, tR 5.28 min.) at 90 mg. The product 1.10-11, (90 mg) was dissolved in methanol with 1 0Oul of DEA and further purified by chiral chromatography using (OJ Column, SFC=1 00ml/min, CO2/MeOH=80/20, 276bar ) to give 1.10-11 (peak 1 , tR 4.33 min.) at 49.5 mg and minor product 1.10-1 (peak 2, tR 6.09 min.).

[00257] 1.10-1 LC-MS (m/z): 415.4 [M+H]+, 0.88 min. ; 1 H NMR (<dmso>) δ: 8.84 (s, 1 H), 7.49 (d, J=8.9 Hz, 1 H), 7.1 7-7.24 (m, 2H), 5.01 (d, J=14.1 Hz, 1 H), 4.91 (br d, J=4.2 Hz, 1 H), 4.45 (dd, J=14.1 , 4.6 Hz, 1 H) , 3.94 (s, 3H), 3.82 (s, 3H), 0.70 (s, 9H)

[00258] 1.10-11 LC-MS (m/z): 415.4 [M+H]+, 0.88 min.; 1 H NMR (<dmso>) δ: 8.84 (s, 1 H), 7.49 (d, J=8.9 Hz, 1 H), 7.1 8-7.25 (m, 2H), 5.01 (br d, J=14.1 Hz, 1 H), 4.91 (br d, J=3.5 Hz, 1 H), 4.45 (br dd, J=14.0, 4.2 Hz, 1 H), 3.94 (s, 3H), 3.82 (s, 3H), 0.70 (s, 9H))

Example 1.11:

6-(tert-butyl)-13-fluoro- 12-methoxy-2-oxo-6, 7-dihydro-2H-pyrido[ 1,2- a]pyrido[3',2':4,5]pyrrolo[2, 1 -c]pyrazine-3-carboxylic acid [1.11-1]

1.11-1

Step 1: ethyl 6-(tert-butyl)-13-fluoro-12-methoxy-2-oxo-6,7-dihydro-2H-pyrido[1,2- a]pyrido[3',2':4,5]pyrrolo[2, 1 -c]pyrazine-3-carboxylate [1.11a-l]

l .l la-l

[00259] To 1.3g-1 (42 mg, 0.106 mmol) was added Acetonitrile (Volume: 2.5 mL), sodium bicarbonate (0.149 mL, 0.149 mmol) cooled in ice bath and then SELECTFLUOR (43.3 mg, 0.122 mmol) was added. The reaction with stirring was allowed to warm to room temperature and stirred for 30 minutes or until done by LCMS. The solution was concentrated to residue, dissolved in 3 ml of DMF, purified by reverse prep LC. The desired fractions were combined, 30 ml of saturated sodium bicarbonate solution was added, extracted with DCM 2x, combined organic layer, wash with saturated salt solution, dried sodium sulfate, filter and concentrate to residue to give 12.5 mg of the desired product 1.11a-1 in 29% yield, used as is. LC-MS (m/z): 414.4 [M+H]⁺, 0.79 min

Step 2: 6-(tert-butyl)-13-fluoro- 12-methoxy-2-oxo-6, 7-dihydro-2H-pyrido[ 1,2- a]pyrido[3',2':4,5]pyrrolo[2, 1 -c]pyrazine-3-carboxylic acid [1.11-1]

1.11-1

To 1.11a-l (12.5 mg, 0.030 mmol) was added THF (Volume: 0.5 mL, Ratio: MeOH (Volume: 0.5 mL, Ratio: 1 .000) and then NaOH 3M aq (0.030 mL, 0.091 mmol) The reaction was stirred at room temperature for 1 hour or until done by LCMS. The solvent was concentrated off to residue, dissolved in 1 ml of DMSO and purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 4.3 mg of the desired product 1.11 -I in 28% yield, as the TFA salt. LC-MS (m/z) : 386.3 [M+H]⁺, 0.80 min.; 1 H NMR (<dmso>) δ: 8.90 (s, 1 H), 8.35 (d, J=5.5 Hz, 1 H), 7.04 (s, 1 H), 6.86 (d, J=5.6 Hz, 1 H), 5.08 (br d, J=14.0 Hz, 1 H), 4.84 (d, J=4.3 Hz, 1 H), 4.40 (dd, J=14.0, 4.6 Hz, 1 H), 4.00 (s, 3H), 0.71 (s, 9H)

Example 2.1:

6-(ten-butyl)-2-oxo-6 -dihydro-2H^yrido[1,2-a]pyri

carboxylic acid [2.1-1] and [2.1-11]

2.1-1 and 2.1-11

Step 1 : (1 H-pyrrolo[2,3-b]pyridin-2-yl)methanol [2.1a]

2.1a

[00261] To methyl 1 H-pyrrolo[2,3-b]pyridine-2-carboxylate (1200 mg, 6.81 mmol) was added THF (Volume: 40 ml_), cooled to about 0 °C then LAH 2M in THF (5.1 1 ml_, 10.22 mmol) was added. The reaction was allowed to warm to room temperature and stirred at room temperature for 1 hour or until done by LCMS. The reaction was cooled in ice bath, then quenched carefully by adding excess water dropwise (0.8 ml). Then as salts formed magnesium sulfate and then sodium sulfate was added. The reaction was removed from ice bath and stirred for 1 hour, filtered through celite, flushed with THF, and concentrated to residue to give 930 mg of the desired product 2.1a in 92% yield, used as is LC-MS (m/z): 149.1 [M+H]⁺, 0.19 min.

Step 2: 2-(((ten-butyldimethylsilyl)oxy)methyl)-1H-pyrro^ [2.1b]

[00262] To 2.1a (930 mg, 6.28 mmol) was added DMF (Volume: 20 ml_), imidazole (513 mg, 7.53 mmol) and TBDMSCI (1041 mg, 6.90 mmol). The reaction was stirred at room temperature for 16 hours or until done by LCMS. To the reaction was added 150 ml of ethyl acetate washed with saturated sodium bicarbonate, water, saturated salt solution, dried sodium sulfate, filtered and concentrated to residue to give the desired product 2.1 b assume in quantitative yield, used as is. LC-MS (m/z) : 263.3 [M+H]⁺, 0.75 min.

Step 3: 1 -(2-(((tert-butyldimethylsilyl)oxy)methyl)- 1 H-pyrrolo[2,3-b]pyridin- 1 -yl)-3,3- dimethylbutan-2-one [2.1c]

2.1c

[00263] To 2.1 b (1580 mg, 6.02 mmol) was added DMF (Volume: 16 ml_), NaH (385 mg, 9.63 mmol) and stirred for 10 minutes at room temperature. Then 1 -bromo-3,3-dimethylbutan- 2-one (1294 mg, 7.22 mmol) was added and stirred at room temperature for 2 hours or until done by LCMS. To the reaction was added 150 ml of ethyl acetate washed with saturated sodium bicarbonate, water, saturated salt solution, dried sodium sulfate, filtered and

concentrated to residue. The crude material was purified by silica gel column chromatography, using 0 to 100% EtOAc/heptanes. The desired regio-isomer eluted first and was concentrated to constant mass to give 450 mg of the desired product 2.1 c in 21 % yield. LC-MS (m/z): 361 .4 [M+H]⁺, 1 .00 min.

Step 4: (1-(2-amino-3,3-dimethylbutyl)-1H^yrrolo[2,3-b]pyridin-2-yl)m^ [2.1 d]

[00264] To 2.1 c (450 mg, 1 .248 mmol) was added MeOH (Volume: 5 ml_), ammonium acetate (1443 mg, 18.72 mmol) and sodium cyanoborohydride (235 mg, 3.74 mmol). . The reaction was then stirred at 50 °C for 48 hours or until done by LCMS. To the crude reaction was added 200 ml of DCM and 15 ml of methanol, extracted with 1 :1 solution of (6 M NaOH, saturated salt solution). The aqueous layer was back extracted with DCM. The organics were combined washed with saturated salt solution, dried with sodium sulfate, filtered through 1 cm x 2cm celite filter plug, washed with a solution of DCM with 10% methanol, concentrated to residue to give 255 mg of the desired product 2. ^"Id in 83% yield, used as is. LC-MS (m/z): 248.3 [M+H]⁺, 0.41 min.

Step 5: 8-(tert-butyl)-8,9-dihydropyrido[ ',2':4,5]pyrrolo[1,2-a]pyrazine [2.1e]

[00265] To 2.1d (255 mg, 1 .031 mmol) was added DCM (Volume: 5 ml_), and manganese dioxide (896 mg, 10.31 mmol). The reaction was then stirred room temperature for 2 hours. Then additional manganese dioxide (448 mg, 5.15 mmol) was added and stirred overnight for a total of 18 hours, or until done by LCMS. Additional manganese dioxide can be added if needed. To the crude was added 30 ml of DCM stirred for 30 minutes then filtered through 1 cm x 2 cm celite filter plug, flushed with DCM and concentrated to residue. The residue was dissolved in 5 ml of DCM and excess TFA (0.238 ml_, 3.09 mmol) was added stirred for 15 minutes at room temperature then concentrated to give the desired product 2.1e assume in quantitative yield, used as is. LC-MS (m/z): 228.3 [M+H]⁺, 0.41 min.

Step 6: ethyl 6-(tert-butyl)-2-oxo-2,6,7, 13b-tetrahydro-1H-pyrido[1,2- a]pyrido[3',2':4,5]pyrrolo[2, 1 -c]pyrazine-3-carboxylate [2.1f]

2.1 f

[00266] To 2.1 e (220 mg, 0.968 mmol) was added Ethanol (Volume: 3.58 ml_), and (Z)- ethyl 2-(ethoxymethylene)-3-oxobutanoate (541 mg, 2.90 mmol). The reaction was then stirred at 95 °C for 5 hours or until done by LCMS. The reaction was concentrated to residue to give the desired product 2.1f assume in quantitative yield, used as is. LC-MS (m/z) : 368.4 [M+H]⁺, 0.61 min.

Step 7: ethyl 6-(tert-butyl)-2-oxo-6 -dihydro-2H-pyrido[1,2-a]pyrido[3 2':4,5]pyrrolo^ 1- c]pyrazine-3-carboxylate [2.1g-l] and [2.1g-ll]

2.1 g-l ^and 2.1 g-ll

[00267] To 2.1f (350 mg, 0.953 mmol) was added DME (Volume: 5 ml_), and then chloranil (234 mg, 0.953 mmol). The reaction was stirred at 90-95 °C for 90 minutes or until done by LCMS. The crude reaction was neutralized with excess TEA and concentrated to residue. The crude material was purified by silica gel column chromatography, using 0 to 1 00% EtOAc(with 20% ethanol)/heptanes. The desired fractions were concentrated to constant mass to give 245 mg of the desired racemic product 2.1 g in 70% yield. LC-MS (m/z) : 366.3 [M+H]⁺, 0.66 min.

[00268] The above racemic material (224 mg) was separated by chiral chromatography using (AD column, SFC=100mL/min, CO₂/EtOH=70/30, 262bar) to give products 2.1 g-l (peak 1 , tR 2.85 min.) at 74 mg and product 2.1 g-ll (peak 2, tR 4.04 min.) at 72 mg.

Step 8: 6-(tert-butyl)-2-oxo-6 -dihydro-2H-pyrido[1,2-a]pyrido[

carboxylic acid [2.1-1] and [2.1-11]

2.1-1 and 2.1 -11

[00269] To 2.1 g-l (74 mg, 0.203 mmol) was added THF (Volume: 0.2 ml, Ratio: 1 .000), MeOH (Volume: 0.2 ml, Ratio: 1 .000) and then NaOH 3M (0.203 ml, 0.608 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 3 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 38 mg of the desired product 2.1 -1 as TFA salt in 41 % yield. LC-MS (m/z) : 338.3 [M+H]⁺, 0.66 min.; ¹ H NMR (DMSO-d₆) δ: 8.93 (s, 1 H), 8.45 (dd, J=4.6, 1 .4 Hz, 1 H), 8.16 (dd, J=7.9, 1 .6 Hz, 1 H), 7.56 (s, 1 H), 7.52 (s, 1 H), 7.26 (dd, J=7.9, 4.7 Hz, 1 H), 5.13 (d, J=14.2 Hz, 1 H), 4.90 (d, J=4.7 Hz, 1 H), 4.52 (dd, J=14.2, 4.7 Hz, 1 H), 0.72 (s, 9H)

[00270] To 2.1 g-ll (72 mg, 0.197 mmol) was added THF (Volume: 0.4 ml, Ratio: 1 .000), MeOH (Volume: 0.4 ml, Ratio: 1 .000) and then NaOH 3M (0.197 ml, 0.591 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 3 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 43 mg of the desired product 2.1 -11 as the TFA salt in 47% yield. LC-MS (m/z) : 338.3 [M+H]⁺, 0.65 min.; ¹ H NMR (DMSO-d₆) δ: 8.93 (s, 1 H), 8.45 (dd, J=4.6, 1 .4 Hz, 1 H), 8.1 6 (dd, J=8.0, 1 .4 Hz, 1 H), 7.56 (s, 1 H), 7.52 (s, 1 H), 7.26 (dd, J=8.0, 4.6 Hz, 1 H), 5.13 (d, J=14.2 Hz, 1 H), 4.90 (d, J=4.4 Hz, 1 H), 4.52 (dd, J=14.2, 4.7 Hz, 1 H), 0.72 (s, 9H)

Example 2.2:

6-(ten-butyl)-2-oxo-6 -dihydro-2H^yrido[1,2-a]pyri

carboxylic acid [2.2-1] and [2.2-11]

2.2-1 and 2.2-11 Step 1 to 7: ethyl 6-(tert-butyl)-2-oxo-6 -dihydro-2H-pyrido[1,2-a]pyrido[4 3':4 c]pyrazine-3-carboxylate [2.2g-l] and [2.2g-ll]

2.2g-l ^and 2.2g-ll

[00271] Compound 2.2g was synthesized from the starting material; methyl 1 H- pyrrolo[2,3-c]pyridine-2-carboxylate by the process of Example 2.1 following steps 1 through 7 resulting in the desired product 2.2g as a racemate. LC-MS (m/z): 366.3 [M+H]⁺, 0.47 min.

[00272] The above racemic material (79 mg) was separated by chiral chromatography using (OD column, SFC=100ml/min, CO₂/MeOH=80/20, 218bar) to give products 2.2g-l (peak 1 , tR 5.55 min.) at 15 mg and product 2.2g-ll (peak 2, tR 7.72 min.) at 14 mg.

Step 8: 6-(tert-butyl)-2-oxo-6, 7-dihydro-2H-pyrido[ 1 ,2-a]pyrido[4 ',3':4,5]pyrrolo[2, 1 -c]pyrazine-3- carboxylic acid [2.2-1] and [2.2-11]

2.2-1 and 2.2-11

[00273] To 2.2g-l (15 mg, 0.041 mmol) was added THF (Volume: 0.2 ml, Ratio: 1 .000), MeOH (Volume: 0.2 ml, Ratio: 1 .000) and then NaOH 3M (0.041 ml, 0.123 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 1 .2 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 8.9 mg of the desired product 2.2-1 as TFA salt in 47% yield. LC-MS (m/z): 338.2 [M+H]⁺, 0.44 min.; ¹ H NMR (DMSO-d₆) δ: 9.70 (s, 1 H), 8.98 (s, 1 H), 8.45 (d, J=6.3 Hz, 1 H), 8.25 (d, J=6.3 Hz, 1 H), 7.87 (s, 1 H), 7.83 (s, 1 H), 5.37 (d, J=14.2 Hz, 1 H), 5.00 (d, J=4.7 Hz, 1 H), 4.77 (dd, J=14.2, 4.7 Hz, 1 H), 0.76 (s, 9H)

[00274] To 2.2g-ll (14 mg, 0.038 mmol) was added THF (Volume: 0.2 ml, Ratio: 1 .000), MeOH (Volume: 0.2 ml, Ratio: 1 .000) and then NaOH 3M (0.038 ml, 0.1 15 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 1 .2 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 7.7 mg of the desired product 2.2-11 as the TFA salt in 44% yield. LC-MS (m/z) : 338.3 [M+H]⁺, 0.44 min.; ¹ H NMR (DMSO-d₆) δ: 9.69 (s, 1 H), 8.98 (s, 1 H), 8.45 (d, J=6.3 Hz, 1 H), 8.24 (br d, J=6.3 Hz, 1 H), 7.86 (s, 1 H), 7.83 (s, 1 H), 5.37 (d, J=14.2 Hz, 1 H), 5.00 (d, J=5.0 Hz, 1 H), 4.76 (dd, J=14.3, 4.9 Hz, 1 H), 0.76 (s, 9H)

Example 2.3:

6-(ten-butyl)-2-oxo-6 -dibydro-2H-pyrido[1,2-a]pyrido[3 4^{^}

carboxylic acid [2.3-1] and [2.3-11]

2.3-1 and 2.3-11

Step 1 to 7: ethyl 6-(tert-butyl)-2-oxo-6 ,7-dihydro-2H-pyrido[1 ,2-a]pyrido[3',4':4,5]pyrrolo[2, 1- c]pyrazine-3-carboxylate [2.3g]

[00275] Compound 2.3g was synthesized from the starting material; ethyl 1 H- pyrrolo[3,2-c]pyridine-2-carboxylate by the process of Example 2.1 following steps 1 through 7 resulting in the desired product 2.3g as a racemate. LC-MS (m/z) : 366.3 [M+H]⁺, 0.46 min.

Step 8: 6-(tert-butyl)-2-oxo-6 -dihydro-2H-pyrido[1,2-a]pyrido[3 4':4,5]pyrrolo[2_^

3-carboxylic acid [2.3-1] and [2.3-11]

2.3-1 and 2.3-11

[00276] To 2.3g (35 mg, 0.096 mmol) was added THF (Volume: 0.2 ml, Ratio: 1 .000), MeOH (Volume: 0.2 ml, Ratio: 1 .000) and then NaOH 3M (0.1 28 ml, 0.383 mmol). At 30 minutes additional NaOH 3M (0.1 28 ml, 0.383 mmol) was added and the reaction was stirred at room temperature for 2 hour or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 5 ml of DMSO, 2ml of water, neutralized with TFA, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 31 mg of the desired racemic product 2.3 as TFA salt in 70% yield. LC-MS (m/z) : 338.2 [M+H]⁺, 0.42 min.; ¹ H NMR (DMSO-d₆) δ: 9.48 (s, 1 H), 8.95 (s, 1 H), 8.65 (d, J=6.6 Hz, 1 H), 8.46 (d, J=6.6 Hz, 1 H), 8.03 (s, 1 H), 7.80 (s, 1 H), 5.35 (d, J=14.2 Hz, 1 H), 5.00 (d, J=4.7 Hz, 1 H), 4.71 (dd, J=14.3, 4.9 Hz, 1 H), 0.74 (s, 9H)

[00277] The above racemic material (28 mg) was dissolved in methanol with 40ul of DEA added and was separated by chiral chromatography using (AD column, SFC = 1 00ml/min, C0₂/MeOH = 83/1 7, 21 6 bar) to give products 2.3-1 (peak 1 , tR 9.32 min.) at 3.7 mg in 13% yield and product 2.3-11 (peak 2, tR 1 0.88 min.) at 8.1 mg in 25% yield.

[00278] 2.3-1 LC-MS (m/z) : 338.3 [M+H]+, 0.49 min. ; ¹ H NMR (<dmso>) δ: 8.95 (s, 1 H), 8.86 (s, 1 H), 8.34 (d, J=5.9 Hz, 1 H), 7.82 (d, J=5.9 Hz, 1 H), 7.62 (s, 1 H), 7.54 (s, 1 H), 5.09 (d, J=14.1 Hz, 1 H), 4.87 (br d, J=4.3 Hz, 1 H), 4.53 (dd, J=14.2, 4.8 Hz, 1 H), 0.69 (s, 9H)

[00279] 2.3-11 LC-MS (m/z) : 338.3 [M+H]+, 0.49 min.; ¹ H NMR (<dmso>) δ: 8.90 (s, 1 H), 8.51 (br s, 1 H), 8.30 (br d, J=5.7 Hz, 1 H), 7.79 (br d, J=5.7 Hz, 1 H), 7.42 (br s, 1 H), 7.07 (br s, 1 H), 5.03 (br d, J=14.0 Hz, 1 H), 4.66 (br s, 1 H), 4.45 (br d, J=1 0.7 Hz, 1 H), 0.68 (s, 9H)

Example 2.4:

6-(tert-butyl)-2-oxo-6 -dihydro-2H-pyrido[1,2-a]pyrido[2 3':4,5]pyrrolo^

carboxylic acid [2.4-1] and [2.4-11]

2.4-1 and 2.4-11

Step 1 to 7: ethyl 6-(tert-butyl)-2-oxo-6 -dihydro-2H-pyrido^

c]pyrazine-3-carboxylate [2.4g-l] and [2.4g-ll]

2.4g-l ^and 2.4g-ll

[00280] Compound 2.4g was synthesized from the starting material; methyl 1 H- pyrrolo[3,2-b]pyridine-2-carboxylate by the process of Example 2.1 following steps 1 through 7 resulting in the desired product 2.4g as a racemate. LC-MS (m/z): 366.4 [M+H]⁺, 0.46 min.

[00281] The above racemic material (149 mg) was separated by chiral chromatography using (OD column, SFC=100ml/min, CO₂/MeOH=80/20, 228bar) to give products 2.4g-l (peak 1 , tR 4.3 min.) at 15 mg and product 2.4g-ll (peak 2, tR 5.83 min.) at 15 mg.

Step 8: 6-(tert-butyl)-2-oxo-6, 7-dihydro-2H-pyrido[ 1,2-a]pyrido[2',3':4,5]pyrrolo[2, 1 -cjpyrazine- 3-carboxylic acid [2.4-1] and [2.4-11]

2.4-1 and 2.4-11

[00282] To 2.4g-l (15 mg, 0.041 mmol) was added THF (Volume: 0.2 ml, Ratio: 1 .000), MeOH (Volume: 0.2 ml, Ratio: 1 .000) and then NaOH 3M (0.055 ml, 0.164 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 1 .2 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 7.5 mg of the desired product 2.4-1 as TFA salt in 40% yield. LC-MS (m/z): 338.3 [M+H]⁺, 0.56 min.; ¹ H NMR (<dmso>) δ: 8.89 (s, 1 H), 8.61 (d, J=4.7 Hz, 1 H), 8.57 (br d, J=8.2 Hz, 1 H), 7.70 (d, J=5.0 Hz, 2H), 7.53 (dd, J=8.3, 4.9 Hz, 1 H), 5.17 (d, J=14.2 Hz, 1 H), 4.92 (d, J=4.6 Hz, 1 H), 4.60 (dd, J=14.2, 4.8 Hz, 1 H), 0.71 (s, 9H).

[00283] To 2.4g-ll (15 mg, 0.041 mmol) was added THF (Volume: 0.2 ml, Ratio: 1 .000), MeOH (Volume: 0.2 ml, Ratio: 1 .000) and then NaOH 3M (0.055 ml, 0.164 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 1 .2 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 7.8 mg of the desired product 2.4-11 as the TFA salt in 41 % yield. LC-MS (m/z): 338.3 [M+H]⁺, 0.56 min.; ¹H NMR (<dmso>) δ: 8.89 (s, 1 H), 8.61 (d, J=4.7 Hz, 1 H), 8.57 (br d, J=8.4 Hz, 1 H), 7.70 (d, J=5.1 Hz, 2H), 7.53 (dd, J=8.3, 4.9 Hz, 1 H), 5.17 (d, J=14.1 Hz, 1 H), 4.92 (d, J=4.5 Hz, 1 H), 4.60 (dd, J=14.2, 4.9 Hz, 1 H), 0.71 (s, 9H).

Example 2.5:

6-(tert-butyl)- 12-methoxy-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3- carboxylic acid [2.5-1] and [2.5-11]

2.5-1 and 2.5-11

Step 1 to 7: ethyl 6-(tert-butyl)-12-methoxy-2-oxo-6 -dihydro-2H-pyrido[2 1 '^

a]indole-3-carboxylate [2.5g-l] and [2.5g-ll]

2.5g-l ^and 2.5g-ll

[00284] Compound 2.5g was synthesized from the starting material; methyl 4-methoxy- 1 H-indole-2-carboxylate by the process of Example 2.1 following steps 1 through 7 resulting in the desired product 2.5g as a racemate. LC-MS (m/z): 395.4 [M+H]⁺, 0.76 min. [00285] The above racemic material (273 mg) was separated by chiral chromatography using (OJ column, SFC=100ml/min, CO₂/MeOH=80/20, 236bar) to give products 2.5g-l (peak 1 , tR 2.23 min.) at 94 mg and product 2.5g-ll (peak 2, tR 3.41 min.) at 88 mg.

Step 8: 6-(tert-butyl)- 12-methoxy-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3- carboxylic acid [2.5-1] and [2.5-11]

2.5-1 and 2.5-11

[00286] To 2.5g-l (94 mg, 0.238 mmol) was added THF (Volume: 0.4 ml, Ratio: 1 .000), MeOH (Volume: 0.4 ml, Ratio: 1 .000) and then NaOH 3M (0.238 ml, 0.715 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 1 .2 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 56.5 mg of the desired product 2.5-1 as TFA salt in 48% yield. LC-MS (m/z): 367.3 [M+H]⁺, 0.77 min.; ¹H NMR (DMSO-d₆) δ: 8.84 (s, 1 H), 7.50 (s, 1 H), 7.47 (s, 1 H), 7.36 (d, J=8.2 Hz, 1 H), 7.27 (t, J=8.0 Hz, 1 H), 6.64 (d, J=7.6 Hz, 1 H), 5.00 (d, J=13.9 Hz, 1 H), 4.84 (d, J=4.4 Hz, 1 H), 4.50 (dd, J=14.2, 4.7 Hz, 1 H), 3.92 (s, 3H), 0.72 (s, 9H)

[00287] To 2.5g-ll (88 mg, 0.223 mmol) was added THF (Volume: 0.4 ml, Ratio: 1 .000), MeOH (Volume: 0.4 ml, Ratio: 1 .000) and then NaOH 3M (0.223 ml, 0.669 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 1 .2 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 55.5 mg of the desired product 2.5-11 as the TFA salt in 51 % yield. LC-MS (m/z): 367.3 [M+H]⁺, 0.77 min.; ¹ H NMR (DMSO-d₆) δ: 8.84 (s, 1 H), 7.50 (s, 1 H), 7.47 (s, 1 H), 7.36 (d, J=8.5 Hz, 1 H), 7.27 (t, J=8.0 Hz, 1 H), 6.64 (d, J=7.9 Hz, 1 H), 5.00 (d, J=14.2 Hz, 1 H), 4.84 (d, J=4.4 Hz, 1 H), 4.50 (dd, J=14.2, 4.7 Hz, 1 H), 3.92 (s, 3H), 0.72 (s, 9H).

Example 2.6:

6-(tert-butyl)-11-methoxy-2-oxo-6,7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[1 ,2-a]indole-3- carboxylic acid [2.6-1] and [2.6-11]

2.6-1 and 2.6-11

Step 1 to 7: ethyl 6-(tert-butyl)- 11 -methoxy-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1,2- a]indole-3-carboxylate [2.6g]

2.6g

[00288] Compound 2.6g was synthesized from the starting material; methyl 5-methoxy- 1 H-indole-2-carboxylate by the process of Example 2.1 following steps 1 through 7 resulting in the desired product 2.6g as a racemate. LC-MS (m/z) : 395.4 [M+H]⁺, 0.76 min.

Step 8: 6-(tert-butyl)-11-methoxy-2-oxo-6,7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[1 ,2-a]indole-3- carboxylic acid [2.6-1] and [2.6-11]

2.6-1 and 2.6-11

[00289] To 2.6g (120 mg, 0.304 mmol) was added THF (Volume: 2 ml, Ratio: 1 .000), MeOH (Volume: 2 ml, Ratio: 1 .000) and then NaOH 3M (0.406 ml, 1 .217 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 5 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 65 mg of the desired racemic product 2.6 as TFA salt in 45% yield. LC-MS (m/z): 367.3 [M+H]⁺, 0.76 min.; ¹H NMR (DMSO-d₆) δ: 8.85 (s, 1 H), 7.71 (d, J=9.1 Hz, 1 H), 7.41 (s, 1 H), 7.37 (s, 1 H), 7.13 (d, J=2.2 Hz, 1 H), 6.99 (dd, J=9.0, 2.4 Hz, 1 H), 5.01 (d, J=14.2 Hz, 1 H), 4.84 (d, J=4.4 Hz, 1 H), 4.48 (dd, J=14.2, 4.7 Hz, 1 H), 3.80 (s, 3H), 0.73 (s, 9H). [00290] The above racemic material (56 mg) was dissolved in methanol with 200μΙ of DEA added and was separated by chiral chromatography using (AD column, SFC=1 00ml/min, C02/MeOH = 65/35, 21 6 bar) to give products 2.6-1 (peak 1 , tR 2.1 7 min.) at 1 9.7 mg in 35% yield and product 2.6-11 (peak 2, tR 4.13 min.) at 21 .0 mg in 36% yield.

[00291] 2.6-1 LC-MS (m/z) : 367.3 [M+H]+, 0.76 min. ; ¹ H NMR (<dmso>) δ: 8.81 (s, 1 H), 7.68 (d, J=9.0 Hz, 1 H), 7.38 (s, 1 H), 7.33 (s, 1 H), 7.1 0 (d, J=2.2 Hz, 1 H), 6.96 (dd, J=9.0, 2.2 Hz, 1 H), 4.98 (br d, J=14.1 Hz, 1 H), 4.80 (br d, J=4.1 Hz, 1 H), 4.45 (br dd, J=14.1 , 4.6 Hz, 1 H), 3.77 (s, 3H), 0.70 (s, 9H).

[00292] 2.6-11 LC-MS (m/z) : 367.3 [M+H]+, 0.76 min.; ¹ H NMR (<dmso>) δ: 8.79 (br s, 1 H), 7.68 (d, J=9.0 Hz, 1 H), 7.36 (br s, 1 H), 7.32 (br s, 1 H), 7.09 (d, J=2.2 Hz, 1 H), 6.95 (dd, J=9.0, 2.2 Hz, 1 H), 4.97 (br d, J=14.1 Hz, 1 H), 4.79 (br s, 1 H), 4.45 (br dd, J=14.1 , 4.4 Hz, 1 H) , 3.77 (s, 3H), 0.70 (s, 9H).

Example 2.7:

6-(tert-butyl)- 10-methoxy-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3- carboxylic acid [2.7-1] and [2.7-11]

2.7-1 and 2.7-11

Step 1 to 7: ethyl 6-(tert-butyl)-10-methoxy-2-oxo-6 -dihydro-2H-pyrido[2 1 ':3 ]pyrazino[1,2- a]indole-3-carboxylate [2.7g-l] and [2.7g-ll]

[00293] Compound 2.7g was synthesized from the starting material; methyl 6-methoxy- 1 H-indole-2-carboxylate by the process of Example 2.1 following steps 1 through 7 resulting in the desired product 2.7g as a racemate. LC-MS (m/z) : 395.4 [M+H]⁺, 0.76 min. [00294] The above racemic material (273 mg) was separated by chiral chromatography using (OJ column, SFC=100ml/min, C0₂/MeOH=85/15, 229bar) to give products 2.7g-l (peak 1 , tR 1 .93 min.) at 70 mg and product 2.7g-ll (peak 2, tR 3.55 min.) at 82 mg.

Step 8: 6-(tert-butyl)- 10-methoxy-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3- carboxylic acid [2.5-1] and [2.5-11]

2.7-1 and 2.7-11

[00295] To 2.7g-l (70 mg, 0.177 mmol) was added THF (Volume: 0.4 ml, Ratio: 1 .000), MeOH (Volume: 0.4 ml, Ratio: 1 .000) and then NaOH 3M (0.177 ml, 0.532 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 2 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re- lyophilized to give 24.4 mg of the desired product 2.7-1 as TFA salt in 28% yield. LC-MS (m/z): 367.3 [M+H]⁺, 0.78 min.; ¹ H NMR (DMSO-d₆) δ: 8.81 (s, 1 H), 7.54 (d, J=8.8 Hz, 1 H), 7.40 (s, 1 H), 7.35 (s, 2H), 6.80 (dd, J=8.8, 2.2 Hz, 1 H), 5.06 (d, J=14.2 Hz, 1 H), 4.83 (d, J=4.4 Hz, 1 H), 4.45 (dd, J=14.2, 4.7 Hz, 1 H), 3.87 (s, 3H), 0.75 (s, 9H).

[00296] To 2.7g-ll (82 mg, 0.208 mmol) was added THF (Volume: 0.4 ml, Ratio: 1 .000), MeOH (Volume: 0.4 ml, Ratio: 1 .000) and then NaOH 3M (0.208 ml, 0.624 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 1 .2 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 28.8 mg of the desired product 2.7-11 as the TFA salt in 28% yield. LC-MS (m/z): 367.3 [M+H]⁺, 0.77 min.; ¹H NMR (DMSO-d₆) δ: 8.81 (s, 1 H), 7.54 (d, J=8.8 Hz, 1 H), 7.40 (s, 1 H), 7.35 (s, 2H), 6.80 (dd, J=8.7, 2.0 Hz, 1 H), 5.06 (d, J=13.9 Hz, 1 H), 4.83 (d, J=4.4 Hz, 1 H), 4.45 (dd, J=14.2, 4.7 Hz, 1 H), 3.87 (s, 3H), 0.74 (s, 9H).

Example 2.8:

6-(tert-butyl)- 12-(3-methoxypropoxy)-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1,2- a]indole-3-carboxylic acid [2.8]

2.8

Step 1 to 7: ethyl 12-(benzyloxy)-6-(tert-butyl)-2-oxo-6,7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-

2.8g

[00297] Compound 2.8g was synthesized from the starting material; 4-(benzyloxy)-1 H- indole-2-carboxylic acid by the process of Example 2.1 following steps 1 through 7 resulting in the desired product 2.8g as a racemate. LC-MS (m/z) : 471 .4 [M+H]⁺, 1 .03 min.

Step 8: ethyl 6-(tert-butyl)-12-hydroxy-2-oxo-6,7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[1 ,2- a]indole-3-carboxylate [2.8h]

2.8h

[00298] To 2.8g (472 mg, 1 .003 mmol) in EtOAc (Volume: 7 mL) with MeOH (Volume: 1 ml_), 10% Pd-C (200 mg, 0.188 mmol) was added after purging with nitrogen. The crude was again purged with hydrogen (from a balloon) and the reaction run under hydrogen overnight for 18 hours or until done by LCMS. The crude was filtered and concentrated to give 408 mg of the desired product 2.8h assume in quantitative yield, used as is. LC-MS (m/z): 381 .4 [M+H]⁺, 0.75 min. Step 9: ethyl 6-(tert-butyl)-12-(3-methoxypropoxy)-2-oxo-6,7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylate [2.8i]

[00299] To 2.8h (40 mg, 0.105 mmol) and 1 -bromo-3-methoxypropane (0.2 ml_, 0.105 mmol) in DMSO (Volume: 1 ml_), cesium carbonate (68.5 mg, 0.210 mmol) was added and stirred at 60 °C for 2 hours or until done by LCMS. The crude solution containing the desired product 2.8i was taken to the next step, assume in quantitative yield, used as is. LC-MS (m/z): 453.4 [M+H]⁺, 0.93 min.

Step 10: 6-(tert-butyl)- 12-(3-methoxypropoxy)-2-oxo-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylic acid [2.8]

2.8

[00300] To the crude solution from Step 9 containing 2.8i (40 mg, 0.088 mmol), 15% sodium hydroxide solution (1 ml_, 3.75 mmol) was added and stirred for 1 hour at room temperature. The solution was acidified (cone. HCI, 0.2ml) and 0.5ml methanol was added. The crude was purified on reverse phase prep LC to give the 24 mg of the desired product 2.8 in 60.8% yield (over 2 steps). LC-MS (m/z): 425.3 [M+H]⁺, 0.99 min.; ¹ H NMR (400 MHz, CDCI3) δ ppm 8.53 (s, 1 H) 7.21 - 7.31 (m, 2 H) 7.19 (s, 1 H) 6.89 - 7.09 (m, 1 H) 6.59 (d, =7.78 Hz, 1 H) 4.80 (d, =13.69 Hz, 1 H) 4.42 (dd, =13.74, 4.74 Hz, 1 H) 4.12 - 4.31 (m, 3 H) 3.64 (t, J=e.14 Hz, 2 H) 3.30 - 3.48 (m, 3 H) 2.17 (quin, =6.19 Hz, 2 H) 0.84 (s, 9 H).

Example 2.9:

6-(tert-butyl)- 12-(2-hydroxyethoxy)-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole- 3-carboxylic acid [2.9]

Step 1: ethyl 6-(tert-butyl)-12-(2-hydroxyethoxy)-2-oxo-6,7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[1,2-a]indole-3-carboxylate [2.9a]

2.9a

[00301] To 2.8h (35 mg, 0.092 mmol) and 2-bromoethan-1 -ol (23 mg, 0.184 mmol) in DMSO (Volume: 1 mL), cesium carbonate (90 mg, 0.276 mmol) was added and stirred at 60 °C for 2 hours or until done by LCMS. The crude solution containing the desired product 2.9a was taken to the next step, assume in quantitative yield, used as is. LC-MS (m/z): 425.2 [M+H]⁺, 0.84 min.

Step 2: 6-(tert-butyl)-12-(2-hydroxyethoxy)-2-oxo-6,7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[1 ,2- a]indole-3-carboxylic acid [2.9]

2.9

[00302] To the crude solution from Step 1 containing 2.9a, 15% sodium hydroxide solution (1 mL, 3.75 mmol) was added and stirred for 1 hour at room temperature. The solution was acidified (cone. HCI, 0.2ml) and 0.5ml methanol was added. The crude was purified on reverse phase prep LC to give the 2.8 mg of the desired product 2.9 in 7.1 % yield. LC-MS (m/z): 397.4 [M+H]⁺, 0. 74 min.; ¹ H NMR (400 MHz, CDCI3) δ ppm 8.48 (s, 1 H) 7.27 - 7.35 (m, 2 H) 7.1 1 - 7.17 (m, 1 H) 6.99 (d, =7.87 Hz, 1 H) 6.60 (d, J=7.87 Hz, 1 H) 4.81 (br d, =13.89 Hz, 1 H) 4.42 (br dd, J=13.84, 4.70 Hz, 1 H) 4.22 - 4.31 (m, 2 H) 4.03 - 4.15 (m, 3 H) 0.84 (s, 9 H).

Example 2.10:

6-(tert-butyl)- 12-(2,2-difluoroethoxy)-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1,2- a]indole-3-carboxylic acid [2.10]

2.10

Step 1: ethyl 6-(tert-butyl)-12-(2,2-difluoroethoxy)-2-oxo-6,7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-

2.10a

[00303] To 2.8h (30 mg, 0.079 mmol) and 2-bromo-1 ,1 -difluoroethane (60 mg, 0.414 mmol) in DMSO (Volume: 1 mL), cesium carbonate (60 mg, 0.184 mmol) was added and stirred at 60 °C for 2 hours or until done by LCMS. The crude solution containing the desired product 2.10a was taken to the next step, assume in quantitative yield, used as is. LC-MS (m/z): 445.4 [M+H]⁺, 0.9 min.

Step 2: 6-(tert-butyl)-12-(2,2-difluoroethoxy)-2-oxo-6 -dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[1 ,2- a]indole-3-carboxylic acid [2.10]

2.10 [00304] To the crude solution from Step 1 containing 2.10a, 15% sodium hydroxide solution (1 mL, 3.75 mmol) was added and stirred for 1 hour at room temperature. The solution was acidified (cone. HCI, 0.2ml) and 0.5ml methanol was added. The crude was purified on reverse phase prep LC to give the 7.8 mg of the desired product 2.10 in 22.5% yield. LC-MS (m/z): LC-MS (m/z): 417.3 [M+H]⁺, 0. 91 min.; ¹H NMR (400 MHz, CDCI3) δ ppm 8.51 (s, 1 H) 7.31 (t, J=8.09 Hz, 1 H) 7.26 (s, 1 H) 7.18 (s, 1 H) 6.91 - 7.1 1 (m, 1 H) 6.57 (d, =7.82 Hz, 1 H) 6.22 (t, =4.08 Hz, 1 H) 4.81 (d, =13.79 Hz, 1 H) 4.26 - 4.51 (m, 3 H) 4.16 (br d, =4.50 Hz, 1 H) 0.84 (s, 9 H).

Example 2.11 :

6-(tert-butyl)- 12-(2-methoxyethoxy)-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole- -carboxylic acid [2.11]

2.11a

[00305] To 2.8h (30 mg, 0.079 mmol) and 1 -bromo-2-methoxyethane (60mg, 0.432 mmol) in DMSO (Volume: 1 mL), cesium carbonate (60 mg, 0.184mmol) was added and stirred at 60 °C for 2 hours or until done by LCMS. The crude solution containing the desired product 2.11a was taken to the next step, assume in quantitative yield, used as is. LC-MS (m/z): 439.4 [M+H]⁺, 0.95 min.

Step 2: 6-(tert-butyl)-12-(2-methoxyethoxy)-2-oxo-6,7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[1 ,2- a]indole-3-carboxylic acid [2.11]

2.11

[00306] To the crude solution from Step 1 containing 2.11a, 15% sodium hydroxide solution (1 mL, 3.75 mmol) was added and stirred for 1 hour at room temperature. The solution was acidified (cone. HCI, 0.2ml) and 0.5ml methanol was added. The crude was purified on reverse phase prep LC to give the 4 mg of the desired product 2.11 in 1 1 .7% yield. LC-MS (m/z) : 41 1 .4 [M+H]⁺, 0. 87 min.; ¹ H NMR (400 MHz, CDCI3) δ ppm 8.51 (s, 1 H) 7.25 - 7.31 (m, 1 0 H) 7.1 7 (s, 1 H) 6.85 - 7.08 (m, 1 H) 6.58 (d, =7.82 Hz, 1 H) 4.80 (d, =13.74 Hz, 1 H) 4.42 (dd, =13.72, 4.67 Hz, 2 H) 4.29 (t, =4.67 Hz, 2 H) 4.1 5 (d, J=4A5 Hz, 1 H) 3.75 - 4.00 (m, 2 H) 3.51 (s, 3 H) 0.83 (s, 9 H).

Example 2. 12:

6-(ten-butyl)-12-(2-(methylamino)-2-oxoethoxy)-2-oxo-6 -dihydro-2 - pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]in

2.12

Step 1: ethyl 6-(tert-butyl)-12-(2-(methylamino)-2-oxoethoxy)-2-oxo-6 -dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[1,2-

2.12a

[00307] To 2.8h (30 mg, 0.079mmol) and 2-bromo-N-methylacetamide (30 mg,

0.197mmol) in DMSO (Volume: 1 mL), cesium carbonate (60 mg, 0.184 mmol) was added and stirred at 60 °C for 2 hours or until done by LCMS. The crude solution containing the desired product 2.12a was taken to the next step, assume in quantitative yield, used as is. LC-MS (m/z): 452.4 [M+H]⁺, 0.75 min.

Step 2: 6-(tert-butyl)- 12-(2-(methylamino)-2-oxoethoxy)-2-oxo-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]in

2.12

[00308] To the crude solution from Step 1 containing 2.12a, 15% sodium hydroxide solution (1 mL, 3.75 mmol) was added and stirred for 1 hour at room temperature. The solution was acidified (cone. HCI, 0.2ml) and 0.5ml methanol was added. The crude was purified on reverse phase prep LC to give 8 mg of the desired product 2.12 in 22.7% yield (over 2 steps). LC-MS (m/z): 424.4 [M+H]⁺, 0.74 min.; ¹H NMR (400 MHz, CDCI3) δ ppm 8.50 (s, 1 H) 7.30 - 7.36 (m, 1 H) 7.21 (d, =19.86 Hz, 2 H) 7.07 (d, =8.36 Hz, 1 H) 6.55 - 6.63 (m, 1 H) 6.59 (br d, =7.87 Hz, 1 H) 4.84 (br d, J=14.18 Hz, 1 H) 4.70 (s, 2 H) 4.38 - 4.51 (m, 1 H) 4.09 - 4.22 (m, 1 H) 2.98 (d, J=4.94 Hz, 3 H) 0.86 (s, 9 H).

Example 2:13:

6-(tert-butyl)-2-oxo-12-((tetrahydro-2H^yran-4-yl)methoxy)-6 -dihyd

pyrido[2', 1 ':3,4]pyrazino[1,2-

Step 1: ethyl 6-(tert-butyl)-2-oxo-12-((tetrahydro-2H-pyran-4-yl)methoxy)-^

pyrido[2', 1 ':3,4]pyrazino[1,2-a]indole-3-carboxylate [2:13a]

2.13a

[00309] To 2.8h (35 mg, 0.092 mmol) and 4-(bromomethyl)tetrahydro-2H-pyran (33 mg, 0.184 mmol) in DMSO (Volume: 1 mL), cesium carbonate (90 mg, 0.276 mmol) was added and stirred at 60 °C for 2 hours or until done by LCMS. The crude solution containing the desired product 2.13a was taken to the next step, assume in quantitative yield, used as is. LC-MS (m/z): 479.2 [M+H]⁺, 1 .01 min.

Step 2: 6-(tert-butyl)-2-oxo- 12-((tetrahydro-2H-pyran-4-yl)methoxy)-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[1,2-

[00310] To the crude solution from Step 1 containing 2:13a, 15% sodium hydroxide solution (1 mL, 3.75 mmol) was added and stirred for 1 hour at room temperature. The solution was acidified (cone. HCI, 0.2ml) and 0.5ml methanol was added. The crude was purified on reverse phase prep LC to give 2 mg of the desired product 2:13 in 6.1 % yield (over 2 steps). LC-MS (m/z): 451 .4 [M+H]⁺, 0.96 min.; ¹H NMR (400 MHz, CDCI3) δ ppm 8.47 (s, 1 H) 7.28 - 7.32 (m, 1 H) 7.13 - 7.23 (m, 2 H) 6.96 (d, =8.27 Hz, 1 H) 6.56 (d, =7.78 Hz, 1 H) 4.80 (br d, =13.99 Hz, 1 H) 4.41 (br dd, =14.06, 4.87 Hz, 2 H) 4.12 (br d, J=4.84 Hz, 1 H) 4.06 (br d,

Hz, 2 H) 0.84 (s, 9 H).

Example 2:14:

6-(tert-butyl)-12-((3,3-difluorocyclobutyl)methoxy)-2-ox

pyrido[2', 1 ':3,4]pyrazino[1,2-a]indole-3-carboxylic acid [2.14]

2.14

Step 1: ethyl 6-(tert-butyl)-12-((3,3-difluorocyclobutyl)methoxy)-2-oxo

pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylate [2.14a]

2.14a

[00311] To 2.8h (35 mg, 0.092 mmol) and 3-(bromomethyl)-1 ,1 -difluorocyclobutane (34 mg, 0.184 mmol) in DMSO (Volume: 1 mL), cesium carbonate (90 mg, 0.276 mmol) was added and stirred at 60 °C for 2 hours or until done by LCMS. The crude solution containing the desired product 2.14a was taken to the next step, assume in quantitative yield, used as is. LCMS (m/z): 485.2 [M+H]⁺, 1 .06 min.

Step 2: 6-(tert-butyl)- 12-((3,3-difluorocyclobutyl)methoxy)-2-oxo-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylic acid [2.14]

2.14

[00312] To the crude solution from Step 1 containing 2.14a, 15% sodium hydroxide solution (1 mL, 3.75 mmol) was added and stirred for 1 hour at room temperature. The solution was acidified (cone. HCI, 0.2ml) and 0.5ml methanol was added. The crude was purified on reverse phase prep LC to give 7.4 mg of the desired product 2.14 in 18.6% yield (over 2 steps). LC-MS (m/z): 457.3 [M+H]⁺, 1 .03 min.; ¹H NMR (400 MHz, CDCI3) δ ppm 8.53 (s, 1 H) 7.28 - 7.33 (m, 1 H) 7.20 (d, =14.57 Hz, 2 H) 6.98 (d, =8.36 Hz, 1 H) 6.56 (d, =7.78 Hz, 1 H) 4.80 (br d, J=13.69 Hz, 1 H) 4.43 (br dd, J=13.52, 4.23 Hz, 1 H) 4.08 - 4.26 (m, 3 H) 2.69 - 2.93 (m, 3 H) 2.41 - 2.69 (m, 2 H) 0.75 - 0.89 (m, 9 H).

Example 2.15:

12-(2-amino-2-oxoethoxy)-6-(tert-butyl)-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1,2- a]indole-3-carboxylic acid [2.15

2.15

Step 1: ethyl 12-(2-amino-2-oxoethoxy)-6-(tert-butyl)-2-oxo-6,7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,

2.15a

[00313] To 2.8h (35 mg, 0.092 mmol) and 2-bromo-N-methylacetamide (25 mg, 0.184 mmol) in DMSO (Volume: 1 mL), cesium carbonate (90 mg, 0.276 mmol) was added and stirred at 60 °C for 2 hours or until done by LCMS. The crude solution containing the desired product 2.15a was taken to the next step, assume in quantitative yield, used as is. LC-MS (m/z): 438.2 [M+H]⁺, 0.81 min.

Step 2: 12-(2-amino-2-oxoethoxy)-6-(tert-butyl)-2-oxo-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]in

[00314] To the crude solution from Step 1 containing 2.15a, 15% sodium hydroxide solution (1 mL, 3.75 mmol) was added and stirred for 1 hour at room temperature. The solution was acidified (cone. HCI, 0.2ml) and 0.5ml methanol was added. The crude was purified on reverse phase prep LC to give 12 mg of the desired product 2.15 in 30.5% yield. LC-MS (m/z): 41 1 .4 [M+H]⁺, 0.73 min.; ¹ H NMR (400 MHz, CD30D) δ ppm 8.65 (s, 1 H) 7.43 (s, 1 H) 7.22 (s, 1 H) 7.19 (br d, =15.80 Hz, 1 H) 7.06 - 7.14 (m, 1 H) 6.46 (d, J=7A8 Hz, 1 H) 4.82 - 5.03 (m, 1 H) 4.61 - 4.75 (m, 2 H) 4.54 (br d, =3.67 Hz, 1 H) 4.37 (br dd, =14.04, 4.1 1 Hz, 1 H) 0.62 - 0.87 (m, 9 H).

Example 2.16:

6-(ten-butyl)-2-oxo-12-((tetrahydro-2H^yran-4-yl)oxy)-6 -dihydro

pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylic acid [2.16]

Step 1: ethyl 6-(tert-butyl)-2-oxo-12-((tetrahydro-2H^yran-4-yl)oxy)-6 -dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-

2.16a

[00315] To 2.8h (30 mg, 0.079 mmol) and 4-bromotetrahydro-2H-pyran (91 mg , 0.552 mmol) in DMSO (Volume: 1 ml_), cesium carbonate (90 mg, 0.276 mmol) was added and stirred at 60 °C for 2 hours or until done by LCMS. The crude solution containing the desired product 2.16a was taken to the next step, assume in quantitative yield, used as is. LC-MS (m/z): 465.4 [M+H]⁺, 0.89 min.

Step 2: 6-(tert-butyl)-2-oxo- 12-((tetrahydro-2H-pyran-4-yl)oxy)-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylic acid [2.16]

2.16

[00316] To the crude solution from Step 1 containing 2.16a, 15% sodium hydroxide solution (1 mL, 3.75 mmol) was added and stirred for 1 hour at room temperature. The solution was acidified (cone. HCI, 0.2ml) and 0.5ml methanol was added. The crude was purified on reverse phase prep LC to give 1 5 mg of the desired product 2.16 in 50.6% yield (over 2 steps). LC-MS (m/z) : 437.4 [M+H]⁺, 0.89 min.; ¹ H NMR (400 MHz, CDCI3) δ ppm 8.54 (s, 1 H) 7.25 - 7.31 (m, 2H) 7.22 (s, 1 H) 6.96 (d, J=8.31 Hz, 1 H) 6.60 (d, =7.87 Hz, 1 H) 4.81 (d, =13.69 Hz, 1 H) 4.71 (br d, =3.77 Hz, 1 H) 4.42 (dd, =13.77, 4.72 Hz, 1 H) 4.13 - 4.28 (m, 1 H) 3.87 - 4.12 (m, 2 H) 3.50 - 3.74 (m, 2 H) 1 .77 - 2.04 (m, 4 H) 0.85 (s, 9 H).

Example 2.17:

6-(tert-butyl)- 12-(difluoromethoxy)-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole- 3-carboxylic acid [2.17]

Step 1: ethyl 6-(tert-butyl)-12-(difluoromethoxy)-2-oxo-6,7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylate [2.17a]

[00317] To 2.8h (30 mg, 0.079 mmol) in Acetonitrile (Volume: 2 mL, Ratio: 1 0.00)-Water (Volume: 0.2 mL, Ratio: 1 .000) cooled to 0-5 °C, sodium hydroxide (95 mg, 0.237 mmol) was added followed by diethyl (bromodifluoromethyl)phosphonate (63.2 mg, 0.237 mmol) in 1 ml MeCN. The crude was stirred for 3 hours under water cooling. The crude was purified on reverse phase prep LC to give 5 mg of the desired product 2.17a in 14% yield. LC-MS (m/z): 431 .3 [M+H]⁺, 0.90 min.;

Step 2: 6-(tert-butyl)- 12-(difluoromethoxy)-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1,2- a]indole-3-carboxylic acid [2.17]

2.17

[00318] To 2.17a (30 mg, 0.070 mmol) in Methanol (Volume: 1 ml_, Ratio: 1 .000), 15% sodium hydroxide solution (1 ml_, 3.75 mmol) was added and stirred for 1 hour at room temperature. The solution was acidified (Cone HCI, 0.2ml) and 0.5ml methanol was added. The crude was purified on reverse phase prep LC to give 4 mg of the desired product 2.17 in 13.5% yield. LC-MS (m/z): 403.3 [M+H]⁺, 0.91 min.; ¹ H NMR (400 MHz, CDCI3) δ ppm 8.53 (s, 1 H) 7.29 - 7.43 (m, 1 H) 7.26 (m, 2 H) 7.22 (d, =6.46 Hz, 1 H) 6.94 (m, 1 H) 6.70 (m, 1 H) 4.84 (d, =13.74 Hz, 1 H) 4.46 (br dd, =13.74, 4.79 Hz, 1 H) 4.18 (br d, J=4.50 Hz, 1 H) 0.85 (s, 9 H).

Example 2.18:

12-(difluoromethoxy)-6-(1-hydroxy-2-methylpropan-2-yl)-11-metho

pyrido[2', 1 ':3,4]pyrazino[ 1 ,2- nd [2.18-11]

Step 1 to 7: ethyl 6-(1-(benzyloxy)-2-methylpropan-2-yl)-12-(difluoromethoxy)-11 -methoxy-2- oxo-6, 7-dihydro-2H-pyrido[2', ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylate [2.18g]

[00319] Compound 2.18g was synthesized from the starting material; 4- (difluoromethoxy)-5-methoxy-1 H-indole-2-carboxylic acid by the process of Example 2.1 and 4- (benzyloxy)-1 -bromo-3,3-dimethylbutan-2-one as 4.1 b in Step 3, following steps 1 through 7 resulting in the desired product 2.18g as a racemate.

Step 8: ethyl 12-(difluoromethoxy)-6-(1-hydroxy-2-methylpropan-2-yl)-11-methoxy-2-oxo-6,7- dihydro-2H-pyrido[2', 1 ':3, 18b]

[00320] To 2.18g (841 mg, 1 .484 mmol) in EtOH (Volume: 30 ml_), Pd-C, 10% Pd-C (1 .2 g, 5.64 mmol) was added after purging with nitrogen. A hydrogen balloon was attached and the solution stirred for 6 hours or until done by LCMS. The solution was filtered and the residue rinsed with methanol and the organics concentrated to residue. The crude was purified by silica gel chromatography using 0 to15% methanol and DCM, the desired fractions were concentrated to constant mass to give the 470 mg of the desired product 2.18h in 66.5% yield used as is. LC-MS (m/z): 477.3 [M+H]⁺, 0.82 min.

Step 9: 12-(difluoromethoxy)-6-( 1-hydroxy-2-methylpropan-2-yl)-11-methoxy-2-oxo-6,7-dihydro- 2H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylic acid [2.18-1] and [2.18-11]

2.18-1 and 2.18-11

[00321] To 2.18h (470 mg, 0.088 mmol) in methanol (5 ml), 10% sodium hydroxide solution (5 ml_, 1 .25 mmol) was added and stirred for 1 hour at room temperature. The solution was acidified (Cone HCI, 0.2ml) and 0.5ml methanol was added. The crude was purified on reverse phase prep LC to give 38 mg of the desired racemic product, 2.18 in 8.59% yield. LCMS (m/z): 449.3 [M+H]⁺, 0.78 min. ¹H NMR (500 MHz, DMSO-d₆) δ ppm 8.77 (s, 1 H) 7.69 (d, J=9.22 Hz, 1 H) 7.51 (s, 1 H) 7.43 (s, 1 H) 7.31 (d, J=9.22 Hz, 1 H) 6.90 - 7.26 (m, 2 H) 5.18 (br s, 1 H) 5.03 (br d, ϋ=λ 4.42 Hz, 1 H) 4.94 (br d, =4.02 Hz, 1 H) 4.47 (br dd, ϋ=λ 3.83, 4.61 Hz, 2 H) 3.88 (s, 3 H) 2.91 - 3.17 (m, 2 H) 0.75 (s, 3 H) 0.36 (s, 3 H)

[00322] The above racemic material (38 mg) was separated by chiral chromatography using (AD column, SFC=100ml/min, C02/MeOH=75/25, 256bar) to give products 2.18-1 (peak 1 , tR 2.74 min.) at 7 mg and product 2.18-11 (peak 2, tR 5.72 min.) at 8 mg.

[00323] 2.18-1: LC-MS (m/z): 449.5 [M+H]⁺, 0.82 min; 1 H NMR (400 MHz, CD30D) δ ppm 8.83 (s, 1 H) 7.50 (d, J=9.05 Hz, 1 H) 7.23 - 7.38 (m, 3 H) 6.86 (m, 1 H) 5.02 (br d, J=14.13 Hz, 1 H) 4.87 - 4.93 (m, 1 H) 4.41 - 4.57 (m, 1 H) 3.93 (s, 3 H) 3.19 - 3.34 (m, 2H) 1 .30 (br t, J=7.24 Hz, 1 H) 0.88 (s, 3 H) 0.44 (s, 3 H)

[00324] 2.18-11: LC-MS (m/z): 449.5 [M+H]⁺, 0.82min; 1 H NMR (400 MHz, CD30D) δ ppm 8.86 (s, 1 H) 7.53 (d, J=9.00 Hz, 1 H) 7.26 - 7.41 (m, 3 H) 6.89 (m, 1 H) 5.05 (br d, J=14.18 Hz, 1 H) 4.90 - 4.95 (m, 1 H) 4.51 (br dd, J=13.94, 4.35 Hz, 1 H) 3.96 (s, 3 H) 3.22 - 3.39 (m, 2 H) 1 .33 (br t, J=7.16 Hz, 1 H) 0.91 (s, 3 H) 0.47 (s, 3 H).

Example 3.1:

(R)-6-isopropyl-2-oxo-6, 7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylic acid [3.1]

Step 1: (R)-2-((tert-butoxycarbonyl)amino)-3-methylbutyl methanesulfonate [3.1a]

3.1a

[00325] To (R)-tert-butyl (1 -hydroxy-3-methylbutan-2-yl)carbamate (5000 mg, 24.60 mmol) was added DCM (Volume: 75 mL), TEA (6.86 mL, 49.2 mmol) and cooled to 0 °C. Then methanesulfonyl chloride (2.300 mL, 29.5 mmol) was added. The reaction was stirred at 0 °C for 1 hour and allowed to warm to room temperature for 1 hour, followed by LCMS. To the reaction was added saturated ammonium chloride solution, the product was extracted with DCM, organic layer washed with saturated sodium chloride solution, dried MgS04, filtered and concentrated to residue to give 6.5 g of the desired product 3.1a in 94% yield, used as is. LC- MS (m/z): 282.2 [M+H]⁺, 0.62 min. Note: (For the LCMS the parent [M+H]⁺, is present but weak, with significant mass peaks typical of a fragment pattern for a BOC group: [M+H]⁺, -56 = 226.2 and [M+H]⁺, -100 = 182.2).

Step 2: (R)-tert-butyl (1-(2-formyl-1 -indol-1-yl)-3-methylbutan-2-yl)carbamate [3.1b]

3.1 b

[00326] To 1 H-indole-2-carbaldehyde (950 mg, 6.54 mmol) (950 mg, 6.54 mmol) was added DMF (Volume: 25 mL) and then NaH (524 mg, 13.09 mmol). The reaction was stirred at room temperature for 5 minutes and then heated for 20 minutes at 60 °C. Then at 60 °C was added 3.1a (2762 mg, 9.82 mmol) and stirred at 60 °C for 16 hours, followed by LCMS. At that time, additional NaH (320 mg, 7.99 mmol) was added and stirred at 60 °C for 20 minutes.

Then additional 3.1a (1 124 mg, 4.00 mmol) was added and stirred at 60 °C for 3 hours more, followed by LCMS. To the reaction was added 250 ml of ethyl acetate washed with saturated sodium bicarbonate solution, water, saturated salt solution, dried sodium sulfate, filtered and concentrated to residue. The crude material was purified by silica gel column chromatography, using 0 to 60% EtOAc/heptanes. The desired fractions were concentrated to constant mass to give 105 mg of the desired product 3.1 b in 5% yield, used as is. LC-MS (m/z): 331 .3 [M+H]⁺, 0.86 min. Note: (For the LCMS the parent [M+H]⁺, is present but weak, with significant mass peaks typical of a fragment pattern for a BOC group: [M+H]⁺, -56 = 275.2 and [M+H]⁺, -100 = 231 .3).

Step 3: (R)-3-isopropyl-3,4-dihydropyrazino[ 1 ,2-a]indole [3.1c]

3.1c

[00327] To 3.1 b (100 mg, 0.303 mmol) was added DCM (Volume: 2 mL), and then TFA (1 mL, 12.98 mmol). The reaction was stirred at room temperature for 1 hour, followed by LCMS. The reaction was concentrated to residue to give the desired product 3.1c assume in quantitative yield, used as is. LC-MS (m/z) : 213.1 [M+H]+, 0.51 min.

Step 4: (6R)-ethyl 6-isopropyl-2-oxo-2,6,7, 13b-tetrahydro-1H-pyrido[2', 1 ':3,4]pyrazino[1 ,2- a]indole-3-carboxylate [3.1d]

3.1d

[00328] To 3.1 c (64 mg, 0.301 mmol) was added Ethanol (Volume: 2 ml_), and then (Z)- ethyl 2-(methoxymethylene)-3-oxobutanoate (156 mg, 0.904 mmol). The reaction was stirred at 95-100 °C for 26 hours or until done by LCMS. The reaction was concentrated to residue to give the desired product 3.1d assume in quantitative yield, used as is. LC-MS (m/z): 353.3 [M+H]+, 0.75 min.

Step 5: (R)-ethyl 6-isopropyl-2-oxo-6 -dihydro-2H^yrido[2 1 ':3 ]pyrazino[1,2-a]indole-3- carboxylate [3.1 e]

3.1e

[00329] To 3.1d (105 mg, 0.298 mmol) was added DME (Volume: 0.2 mL), and then chloranil (73.3 mg, 0.298 mmol). The reaction was stirred at 90-95 °C for 90 minutes or until done by LCMS. The crude reaction was concentrated to residue and purified by silica gel column chromatography, using 0 to 100% (EtOAc with 10% Methanol)/heptanes. The desired fractions were concentrated to constant mass to give 80 mg of the desired product 3.1 e in 77% yield, used as is. LC-MS (m/z): 351 .3 [M+H]⁺, 0.71 min.

Step 6: (R)-6-isopropyl-2-oxo-6,7-dihydro-2H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylic acid [3.1]

3.1

[00330] To 3.1e (60 mg, 0.171 mmol) was added THF (Volume: 2, Ratio: 1 .000), MeOH (Volume: 2, Ratio: 1 .000) and then NaOH 3M (228 μΙ, 0.685 mmol). The reaction was stirred at room temperature for 2 hours or until done by LCMS. The solvent was concentrated off, the residue was dissolved in 2.5 ml of DMSO with 5% water, purified by reverse phase prep LC, and lyophilized. The product was re-dissolved in 1 :1 ACN/water and re-lyophilized to give 37.5 mg of the desired product 3.1 as TFA salt in 49% yield. LC-MS (m/z): 323.2 [M+H]⁺, 0.75 min.; ¹ H NMR (DMSO-d₆) δ: 8.92 (s, 1 H), 7.75 (d, J=8.2 Hz, 1 H), 7.69 (d, J=7.9 Hz, 1 H), 7.52 (s, 1 H), 7.46 (s, 1 H), 7.34 (t, J=7.3 Hz, 1 H), 7.16 (t, J=7.3 Hz, 1 H), 5.00 (d, J=13.6 Hz, 1 H), 4.81 (br dd, J=9.0, 2.7 Hz, 1 H), 4.47 (dd, J=13.7, 3.6 Hz, 1 H), 1 .62 (br dd, J=15.4, 6.6 Hz, 1 H), 0.90 (d, J=6.6 Hz, 3H), 0.74 (d, J=6.6 Hz, 3H).

Example 4.1:

12-(difluoromethoxy)-6-( 1 -hydroxy-2-methylpropan-2-yl)-2-oxo-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indol -3-carboxylic acid [4.1-1] and [4.1-11]

4.1

Step 1 : 4-(benzyloxy)-3,3-dimethylbutan-2-one [4.1a]

4.1a

[00331] A mixture of 4-hydroxy-3,3-dimethylbutan-2-one (43 g, 370 mmol) and benzylbromide (48.4 ml, 407 mmol) in DIPEA (71 .1 ml, 407 mmol) was heated at 150 °C for 1 hour. After being cooled to room temperature, the mixture was partitioned between ethyl acetate and water. The aqueous layer was adjusted to pH=1 -2 with 2 M hydrochloride acid. Then the organic layer was separated, dried over anhydrous Na₂S0₄ and concentrated to give 76 g of the desired product 4.1a in 100 % yield. LC-MS (m/z): 207.3 [M+H]+, 0.93 min.

NMR (400 MHz, CDCI3) δ ppm 7.26 - 7.38 (m, 5 H), 4.47 - 4.53 (m, 2 H), 3.45 - 3.54 (t 2.16 (s, 3 H), 1 .1 1 - 1 .17 (m, 6 H).

Step 2: 4-(benzyloxy)-1-bromo-3,3-dimethylbutan-2-one [4.1b]

4.1 b

[00332] To 4.1a (5 g, 24.24 mmol) in methanol (Volume: 300 mL) cooled to below 0 °C with ice-methanol, Bromine (1 .436 mL, 27.9 mmol) in 50 ml methanol was added dropwise. The reaction is stirred for 1 hour at that temperature and then overnight at room temperature. The crude was concentrated, re-dissolved in DCM, washed with sat. Sodium bicarbonate and the organics concentrated to residue to give the desired product 4.1 b, assume in quantitative yield, used as is. LC-MS (m/z): 285.1 /287.1 [M+H]+, 1 .06 min. ¹H NMR (400 MHz, CDCI3) δ ppm 7.24 - 7.38 (m, 5 H), 4.48 - 4.51 (m, 2 H), 4.21 - 4.25 (m, 2 H), 3.40 - 3.48 (m, 2 H), 1 .22 - 1 .25 (m, 6 H).

Step 3: (4-(difluoromethoxy)-1H-indol-2-yl)methanol [4.1c]

4.1 c

[00333] To 4-(difluoromethoxy)-1 H-indole-2-carboxylic acid (1950 mg, 8.58 mmol) was added THF (Volume: 50 mL), heated to dissolve then cooled to about room temperature. Then LAH 2M in THF (6.44 mL, 12.88 mmol) was added. The reaction was stirred for 3 hours at room temperature or until done by LCMS. The reaction was cooled in ice bath, then quenched carefully by adding excess water dropwise (2 ml) and as salts formed magnesium sulfate was added. The reaction was removed from ice bath and stirred for 1 hour, filtered through celite plug and concentrated to residue give 1800 mg of the desired product 4.1 c in 98% yield, used as is. LC-MS (m/z): 214.0 [M+H]⁺, 0.63 min.

Step 4: 2-(((tert-butyldimethylsilyl)oxy)methyl)-4-(difluoromethoxy)-1H-indole [4.1d]

[00334] To 4.1 c (1790 mg, 8.40 mmol) was added DCM (Volume: 65 mL) and imidazole (1829 mg, 26.9 mmol) stirred at room temperature for 5 minutes. Then TBDMSCI (3797 mg, 25.2 mmol) was added. The reaction was stirred at room temperature for 90 minutes or until done by LCMS. To the reaction was added 10 ml of methanol and most of solvent off was concentrated off. Then 250 ml of ethyl acetate was added washed with saturated sodium bicarbonate, water, saturated salt solution, dried sodium sulfate, filtered and concentrated to residue. The crude was purified by silica gel chromatography using 0-25% heptane and ethyl acetate. The desired fractions were concentrated to constant mass to give 2740 mg of the desired product 4.1 d assume in 100% yield, used as is. LC-MS (m/z): 328.4 [M+H]⁺, 1 .16 min.

Step 5: 4-(benzyloxy)-1 -(2-(((tert-butyldimethylsilyl)oxy)methyl)-4-(difluoromethoxy)-1H-i yl)-3,3-dimethylbutan-2-one [4.1

4.1e

[00335] To 4.1d (2740 mg, 8.37 mmol) was added DMF (Volume: 40 mL), CESIUM CARBONATE (6816 mg, 20.92 mmol) and stirred for 15 minutes at 45-50 °C. Then 4.1 b (4295 mg, 15.06 mmol) was added and stirred at 45-50 °C for 2 hours or until done by LCMS. The reaction was let cool, then 250 ml of ethyl acetate with 20% heptane was added, washed with saturated bicarbonate, water 2x, saturated salt solution, dried sodium sulfate, filtered and concentrated to residue. The crude material was purified by silica gel chromatography using 0- 20% ethyl acetate and heptane. The desired fractions were concentrated to constant mass to give 4200 mg of desired product 4.1 e in 94% yield. LC-MS (m/z): 532.5 [M+H]+, 1 .48 min.

Step 6: (1-(2-amino-4-(benzyloxy)-3,3-dimethylbutyl)-4-(difluoromethoxy)-1H-indol-2- yl) methanol [4.1f]

[00336] To 4.1e (4215 mg, 7.93 mmol) was added MeOH (Volume: 30 ml_), ammonium acetate (9166 mg, 1 19 mmol) and sodium cyanoborohydride (1495 mg, 23.78 mmol). The reaction was then stirred at 60-65 °C for 20 hours. Then additional ammonium acetate (9166 mg, 1 19 mmol) and sodium cyanoborohydride (1495 mg, 23.78 mmol) was added and stirrred at 60-65 °C overnight for total of 40 hours or until done by LCMS. To the crude reaction was added 750 ml of DCM and, extracted with 1 :1 solution of (6 M NaOH, saturated salt solution). The aqueous layer was back extracted with DCM. The organics were combined washed with saturated salt solution, dried with sodium sulfate, filtered through 1 cm x 2 cm celite filter plug, washed with a solution of DCM with 10% methanol, concentrated to residue to give 3310 mg of the desired product 4.1f in 100% yield, used as is. LC-MS (m/z) : 419.5 [M+H]⁺, 0.88 min.

Step 7: 3-(1-(benzyloxy)-2-methylpropan-2-yl)-9-(difluoromethoxy)-3,4-dihydropy 1,2- a]indole [4.1g]

[00337] To 4.1f (3310 mg, 7.91 mmol) was added DCM (Volume: 45 ml_), and manganese dioxide (6876 mg, 79 mmol). The reaction was then stirred at room temperature for 2 hours. Then additional manganese dioxide (3438 mg, 39.5 mmol) was added and stirred overnight for total of 20 hours or until done by LCMS. Additional manganese dioxide can be added if needed. To the crude was added 50 ml of DCM stirred for 30 minutes, then filtered through 1 cm x 4 cm celite filter plug, flushed with DCM and concentrated to residue. The free base was dissolved in 5 ml of DCM and excess TFA (1 .828 ml_, 23.73 mmol) was added, stirred for 15 minutes at room temperature then concentrated to residue to give the desired product 4.1 g assume in quantitative yield, used as is. LC-MS (m/z): 399.4 [M+H]⁺, 0.90 min. Step 8: ethyl 6-(1-(benzyloxy)-2-methylpropan-2-yl)-12-(difluoromethoxy)-2-oxo-2,6,7, 13b- tetrahydro-1H-pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylate [4.1h]

4.1 h

[00338] To 4.1 g (1550 mg, 3.89 mmol) was added ethanol (Volume: 15 ml_), and (Z)- ethyl 2-(ethoxymethylene)-3-oxobutanoate (2173 mg, 1 1 .67 mmol). The reaction was then stirred at 85-90 °C for 16 hours or until done by LCMS. The reaction was concentrated to residue to give the desired product 4.1 h assume in quantitative yield, used as is. LC-MS (m/z): 539.5 [M+H]⁺, 1 .14 min.

Step 9: ethyl 6-(1-(benzyloxy)-2-methylpropan-2-yl)-12-(difluoromethoxy)-2-oxo-6,7-dihydro- 2H-pyrido[2', 1 ':3,4]pyrazino[1 ,2-a]indole-3-carboxylate [4.11]

[00339] To 4.1 h (2090 mg, 3.88 mmol) was added DME (Volume: 20 ml_), and then chloranil (954 mg, 3.88 mmol). The reaction was stirred at 90-95 °C for 90 minutes or until done by LCMS. The reaction was let cool, 1 ml of water was added stirred for 5 minutes then diluted with 300 ml of DCM with 2% ethanol. Then saturated sodium bicarbonate 75 ml and 150 ml of water was added, stirred for 5 minutes, filtered and then the layers were separated. The organic layer was washed with water 2x, saturated salt solution, dried with sodium sulfate, filtered and concentrated to residue. The crude material was, purified by silica gel

chromatography using 0 to 70% (ethyl acetate with 25% ethanol) and heptane. The desired fractions were concentrated to constant mass to give 801 mg of the desired racemic product 4.1 i in 39% yield. LC-MS (m/z): 537.4 [M+H]⁺, 1 .06 min.

Step 10: 12-(difluoromethoxy)-6-( 1-hydroxy-2-methylpropan-2-yl)-2-oxo-6,7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-a]indole-3-carboxylic acid [4.1-1] and [4.1-11]

4.1-1 and 4.1 -11

[00340] To 4.1 i (660 mg, 1 .230 mmol) was added DCM (Volume: 7 mL) and stirred to dissolve. Then was added boron trichloride, methyl sulfide 2M in DCM (8.61 mL, 1 7.22 mmol) and the reaction was stirred at 25-30 °C for 40 hours or until done by LCMS. The reaction was let cool, 30 ml of DCM was added placed in -1 0 °C bath and with stirring excess ethyl acetate was slowly added. Then still in -1 0 °C bath, excess water (5ml) was added and with stirring allowed to warm to room temperature. The water layer was acidified with 1 N HCL and stirred for 1 5 minutes. Then the aqueous layer was extracted with 75 ml of DCM with 5% ethanol (2x), the organic layers were combined, washed water, saturated salt solution, dried sodium sulfate, filtered and concentrated to residue. The crude material was purified by silica gel

chromatography using 0 to1 00% (ethyl acetate with 40% ethanol) and heptane, the desired fractions were concentrated to residue. Then the crude material was dissolved in 10 ml of DMSO with 5% water and purified by reverse phase prep LC and lyophilized to give 145 mg of the desired racemic product 4.1 as TFA salt in 21 % yield. LC-MS (m/z) : 41 9.4 [M+H]⁺, 0.82 min. 1 H NMR (<dmso>) δ: 8.76 (s, 1 H), 7.64 (d, J=8.4 Hz, 1 H), 7.54 (s, 1 H), 7.52 (s, 1 H), 7.32 (t, J=8.1 Hz, 1 H), 7.1 9-7.59 (m, 1 H), 6.90 (d, J=7.7 Hz, 1 H), 5.1 7 (br s, 1 H), 5.06 (d, J=14.1 Hz, 1 H), 4.94 (d, J=4.3 Hz, 1 H), 4.49 (dd, J=14.1 , 4.6 Hz, 1 H), 2.99-3.1 5 (m, 2H), 0.72 (s, 3H), 0.33 (s, 3H)

[00341] The above racemic material (142 mg) was dissolved in methanol with 1 0Oul of DEA added and was separated by chiral chromatography using (OD column, SFC=100ml/min, C02/EtOH =70/30, 246bar) to give products 4.1 -1 (peak 1 , tR 2.57 min.) at 53.6 mg in 37% yield and product 4.1 -11 (peak 2, tR 7.05 min.) at 52.5 mg in 37% yield.

[00342] 4.1 -1 LC-MS (m/z): 419.3 [M+H]+, 0.82 min.; 1 H NMR (<dmso>) δ: 8.76 (s, 1 H), 7.64 (d, J=8.5 Hz, 1 H), 7.54 (s, 1 H), 7.52 (s, 1 H), 7.32 (t, J=8.1 Hz, 1 H), 7.1 7-7.59 (m, 1 H), 6.90 (d, J=7.7 Hz, 1 H), 5.1 7 (t, J=4.7 Hz, 1 H), 5.06 (d, J=14.1 Hz, 1 H), 4.94 (d, J=4.3 Hz, 1 H), 4.49 (dd, J=14.2, 4.6 Hz, 1 H) , 2.98-3.1 6 (m, 2H), 0.72 (s, 3H), 0.33 (s, 3H).

[00343] 4.1 -11 LC-MS (m/z): 419.4 [M+H]+, 0.82 min.; 1 H NMR (<dmso>) δ: 8.76 (s, 1 H), 7.64 (d, J=8.4 Hz, 1 H), 7.54 (s, 1 H), 7.52 (s, 1 H), 7.32 (t, J=8.1 Hz, 1 H), 7.1 9-7.59 (m, 1 H), 6.90 (d, J=7.7 Hz, 1 H), 5.1 7 (t, J=4.6 Hz, 1 H), 5.06 (d, J=14.1 Hz, 1 H), 4.94 (d, J=4.3 Hz, 1 H), 4.49 (dd, J=14.2, 4.6 Hz, 1 H) , 2.99-3.1 5 (m, 2H), 0.72 (s, 3H), 0.33 (s, 3H). Example 4.2:

12-(difluoromethoxy)- 1 -fluoro-6-( 1 -hydroxy-2-methylpropan-2-yl)-2-oxo-6, 7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[1,2-

4.2

Step 1: (Z)-ethyl 2-(ethoxymethylene)- -difluoro-3-((trimethylsilyl)oxy)but-3-enoate [4.2a]

[00344] Under an argon atmosphere, a mixture of magnesium powder (1 .518 g, 62.5 mmol) and trimethylsilyl chloride (7.40 mL, 58.3 mmol)) was sonicated prior to the reaction for 15-20 minutes. Then a solution of ethyl (Z)-2-(ethoxymethylene)-4,4,4-trifluoro-3-oxobutanoate (2 g, 8.33 mmol) in dry DMF(3 ml) was added dropwise over 5-6 minutes at 50 °C under an argon atmosphere. The reaction mixture was stirred for additional 30 min. at 50 °C. The crude mixture was then filtered through a disposable filter funnel with polyethylene frit. The resulting DMF solution with the desired product 4.2a assume in quantitative yield, used as is.

Step 2: ethyl 6-(1 -(benzyloxy)-2-methylpropan-2-yl)-12-(difluoromethoxy)-1 -fluoro-2-oxo-6,7- dihydro-2H-pyrido[2', 1 ':3,4]pyra .2b]

[00345] To 4.1 g (950 mg, 2.384 mmol), crude 4.2a (3509 mg, 1 1 .92 mmol) from above was added. Acetonitrile (Volume: 10 mL) and zinc iodide (761 mg, 2.384 mmol) was then added and the crude refluxed overnight at 50-60 °C. The crude was purified by silica gel chromatography using 0 to100% (EtOAc:EtOH= 75:25) and heptane the desired fractions were concentrated to constant mass to givel .14 g of the desired product 4.2b in 86% yield. LC-MS (m/z): 555.5 [M+H]⁺, 1 .05 min.

Step 3: 12-(difluoromethoxy)-1-fluoro-6-(1-hydroxy-2-methylpropan-2-yl)-2-oxo-6,7-dihydro-2H- pyrido[2', 1 ':3,4]pyrazino[ 1 ,2-

[00346] To 4.2b (1 .1 g, 1 .984 mmol) boron trichloride Me2S, 2M in DCM (20 ml_, 40.0 mmol) was added and stirred overnight at 28 °C for 17 hours. The crude was quenched by pouring into crushed ice and extracting the crude with DCM. The organics were concentrated and purified on reverse phase prep LC to give 14 mg of the desired product 4.2 in 2% yield. LC-MS (m/z): 437.4 [M+H]⁺, 0.83 min; ¹H NMR (400 MHz, CD30D) δ ppm 8.75 (s, 1 H) 7.43 (br d, =8.22 Hz, 1 H) 7.19 - 7.36 (m, 2 H) 6.73-7.10 (m, 1 H) 6.79 - 6.88 (m, 1 H) 4.98 - 5.09 (m, 1 H) 4.84 - 4.98 (m, 1 H) 4.39 - 4.57 (m, 1 H) 3.07 - 3.18 (m, 2 H) 0.79 (s, 3 H) 0.34 (s, 3 H).

Biological Examples

HBV Cell Line

[00347] HepG2-Clone42, a Tet-inducible HBV-expressing cell line with a stably integrated 1 .3mer copy of the HBV ayw strain, was generated based on the Tet-inducible HepAD38 cell line with slight modifications. Ladner SK, et al., Antimicrobial Agents and Chemotherapy. 41 (8):1715-1720 (1997). HepG2-Clone42 cells were cultured in DMEM/F-12 + Glutamax™ (Life Technologies, Carlsbad, CA, USA), supplemented with 10% fetal bovine serum (Life Technologies), G-418 (Corning, Manassas, VA, USA) at a final concentration of 0.5 mg/mL, and 5 μg/mL Doxycycline (Sigma, St. Louis, MO, USA) and maintained in 5% C0₂ at 37°C.

HBsAg Assay

[00348] HepG2-Clone42 cells were seeded into black clear-bottom 96-well plates at a concentration of 6.0 x 10⁴ cells/well. 24 hours post-seeding, the cells were treated with 200 μΙ/well of media containing five-fold serial dilutions of compounds in DMSO. DMSO alone was used as the no drug control. The final DMSO concentration in all wells was 0.5%. [00349] The HBsAg ELISA kit (Alpha Diagnostic International, San Antonio, TX, USE, Catalog # 41 10) was used to determine the level (semi-quantitative) of secreted HBV sAg. The HBSAg ELISA assay was performed following the manufacturer's protocol as described.

[00350] Step 1 . Pipet 100 μΙ_ each of compound or DMSO treated samples into HBsAg ELISA plates. Seal plates and incubate at room temp for 60 minutes.

[00351] Step 2. Aspirate samples and wash three times with Wash Buffer. Dispense 100 μΐ of antibody-HRP conjugate to each well. Incubate at room temp for 30 minutes.

[00352] Step 3. Aspirate samples and wash three times with Wash Buffer. Add 100 μΐ of TMB Substrate to all wells and incubate 15 minutes at room temp.

[00353] Step 4. Dispense 100 μΐ of Stop Solution to each well. Measure absorbance of ELISA plate at 450 nm.

Dose Response Curves

[00354] Dose-response curves were generated and the EC₅₀ value was defined as the compound concentration at which HBsAg secretion was reduced 50% compared to the DMSO control.

[00355] EC₅₀ values were determined as follows:

[00356] Determine the percent of HBsAg secretion inhibition. Calculate the percent inhibition on of HBsAg secretion inhibition using the following equation:

(Xc - M_B)/(M_D - M_B)

where X_c is the absorbance signal from compound-treated well; M_B is average absorbance signal (background signal) for column 12 (no cells + HBsAg ELISA sample buffer) and M_D is average absorbance signal from DMSO-treated wells. Then calculate EC₅₀ values by non-linear regression using a four parameter curve logistic equation.

[00357] The curve fit model employed is XLFit Dose Response One Site Model 204: y = (A+((B-A)/(1 +(10^A((C-x)^*D))))) where A is the minimum y value, B is the maximum y value, C is the logEC50 value, and D is the slope factor.

Table 1. In Vitro activity of selected compounds of Formula (I).

1.3-1 0.8

1.3-11 19

1.4 230

1.5-1 550

1.5-11 6930

1.6-1 0.805

1.6-11 14.7

1.7-1 4.29

1.7-11 0.145

1.8-1 4.07

1.8-11 38.8

1.9-1 21.3

1.9-11 0.763

1.10-1 7.52

1.10-11 0.483

1.11-1 0.376

2.1-1 8

2.1-11 156

2.2-1 85

2.2-11 4232

2.3-1 885

2.3-11 21

2.4-1 578

2.4-11 13

2.5-1 385

2.5-11 1.2

2.6-1 755

2.6-11 4

2.7-1 178

2.7-11 5

2.8 27.7

2.9 21.2

2.10 1.49

2.11 25.3 2.12 127

2.13 41.9

2.14 25.7

2.15 5870

2.16 137

2.17 0.182

2.18-1 0.066

2.18-11 1.05

3.1 33

4.1-1 156

4.1-11 0.003

4.2 5.44

Claims

1 . A compound of formula (I):

(I) wherein:

R¹ is H, halo, C₁ -C3 alkyl or C₁-C3 haloalkyl;

R² is H, halo, CN, C₁-C3 alkyl, Ci-C₃ haloalkyl, -OR, or -C(0)NR₂;

W is -COOR³, -C(0)NH-S0₂R, -C(0)NH-S0₂NR₂, 5-tetrazolyl, or 1 ,2,4-oxadiazol-3-yl- 5(4H)-one;

R³ is H or CrC₆ alkyl that is optionally substituted with one to three groups selected from halo, -OR, oxo, CN, and -NR₂;

Z¹ is N or CR^z1 ;

Z² is N or CR^Z2;

Z³ is N or CR^Z3;

Z⁴ is N or CR^Z4;

provided not more than one of Z¹ , Z², Z³ and Z⁴ is N;

R^Z1 is H, OH, halo, CN, Ci-C₃ alkyl optionally substituted with up to three groups selected from oxo, halo, -CN, R, -OR, -NR₂, and -C(0)NR₂, or d-C₃ alkoxy optionally substituted with up to three groups selected from halo, oxo, CN, R, -OR, -NR₂, and -C(0)NR₂;

R^Z2 is selected from H, halo, R⁴, -OR⁴, -SR⁴, and -NRR⁴;

R⁴ is C₁ -C4 alkyl, C₃-C₆ cycloalkyi, oxetanyl, tetrahydrofuranyl, or tetrahydropyranyl, each of which is optionally substituted with up to three groups selected from halo, CN, -OR, C₁ -C3 haloalkoxy, -CONR₂, C₃-C₆ cycloalkyi, and a 4-7 membered heterocyclic group containing one or two heteroatoms selected from N, O and S as ring members, wherein the C₃-C₆ cycloalkyi and 4-7 membered heterocyclic group are each optionally substituted with one or two groups selected from halo, oxo, CN, R, -OR, and -NR₂;

R is independently selected at each occurrence from H and Ci-C₃ alkyl optionally substituted with one to three groups selected from halo, -OH, Ci-C₃ alkoxy, oxo, CN, -NH₂, - NH(Ci-C₃ alkyl) , -N(Ci-C₃ alkyl)₂, and cyclopropyl; and two R groups directly attached to the same atom can optionally be taken together to form a 3-6 membered ring that can optionally contain a heteroatom selected from N, O and S as a ring member, and can be substituted by up to two groups selected from -OH, oxo, C C₃ alkyl, and C1 -C3 alkoxy;

R^Z3 is H, OH, halo, CN, C1 -C3 alkyl, C₃-C₆ cycloalkyl, C1-C3 haloalkyl, or -OR;

R^Z4 is H, OH, halo, CN, Me, OMe, or CF₃;

R⁶ is H, halo, C1-C3 alkoxy, or d-C₆ alkyl, or is taken together with R⁹ to form a ring as described below;

R⁷ is H, halo, C1-C3 alkoxy, or d-C₆ alkyl, or is taken together with R⁹ to form a ring as described below;

R⁸ is H or C C₆ alkyl;

R⁹ is H, Ci-C₆ alkyl optionally substituted with up to three groups selected from C₃-C₆ cycloalkyl, -OR, -NR₂, halo, CN, COOR, CONR₂, and oxo,

or R⁹ can be a ring selected from C₃-C₆ cycloalkyl, phenyl, 5-6 membered heterocyclyl containing one or two heteroatoms selected from N, O and S as ring members, and 5-6 membered heteroaryl containing one or two heteroatoms selected from N, O and S as ring members, wherein each of these rings is optionally substituted with up to three groups selected from C1 -C2 alkyl, -OR, -NR₂, halo, CN, COOR, CONR₂, and oxo;

or R⁹ taken together with either R⁶ or R⁷ forms a 3-7 membered cycloalkyl ring or a 3-7 membered heterocyclic ring containing N, O or S as a ring member; wherein the cycloalkyl or heterocyclic ring is optionally substituted with up to three groups selected from R, -OR, -NR₂, halo, CN, COOR, CONR₂, and oxo;

or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, wherein R¹ is H or F.

3. The compound according to any one of the preceding claims, or a

pharmaceutically acceptable salt thereof, wherein R² is H, Me, CN, halo, or OMe.

4. The compound according to any one of claims 1 to 3, wherein W is -COOR³; or a pharmaceutically acceptable salt thereof.

5. The compound of any of claims 1 -4, wherein R⁶ is H and R⁷ is H;

or a pharmaceutically acceptable salt thereof.

6. The compound of any of claims 1 -5, wherein R⁹ is Ci-C₆ alkyl optionally substituted with up to three groups selected from C₃-C₆ cycloalkyi, -OR, -NR₂, halo, CN, COOR, CONR₂, and oxo;

or a pharmaceutically acceptable salt thereof.

7. The compound of any of claims 1 -4, wherein R⁹ taken together with either R⁶ or R⁷ forms a 3-7 membered cycloalkyi ring or a 3-7 membered heterocyclic ring containing N, O or S as a ring member; wherein the cycloalkyi or heterocyclic ring is optionally substituted with up to three groups selected from R, -OR, -NR₂, halo, CN, COOR, CONR₂, and oxo; or a pharmaceutically acceptable salt thereof.

8. The compound of any of claims 1 -7, wherein:

z¹ is CR^Z1

z² is CR^Z2

z³ is CR^Z3

z⁴ is CR^Z4

or a pharmaceutically acceptable salt thereof.

9. The compound of any one of claims 1 -7, wherein one of Z¹, Z², Z³ and Z⁴ is N; or a pharmaceutically acceptable salt thereof.

10. The compound of any of claims 1 -7, which is of the formula:

wherein Z¹ is CR^Z1 ;

Z² is CR^Z2;

Z³ is CR^Z3;

Z⁴ is CR^Z4;

and R³ is H or C1-C4 alkyl;

or a pharmaceutically acceptable salt thereof.

1 1 . A compound according to any of claims 1 -5, wherein R⁹ is isopropyl, t-butyl, cyclopropyl, cyclobutyl, phenyl, or thiophene, and is optionally substituted with up to three groups selected from C C₂ alkyl, -OR, -NR₂, halo, CN, COOR, and CONR₂; or a

pharmaceutically acceptable salt thereof.

12. A compound according to any of claims 1 -1 1 , wherein R⁸ is H; or a

pharmaceutically acceptable salt thereof.

13. A compound according to any one of claims 1 -1 1 , wherein R^Z1 is H, halo, haloalkyl, or -OR;

or a pharmaceutically acceptable salt thereof.

14. The compound of any one of claims 1 -12, wherein R^Z2 is selected from H, halo, Ci-2 haloalkyl, -OMe, and -OR;

or a pharmaceutically acceptable salt thereof.

1 5. The compound of any one of claims 1 -1 2, wherein R ³ is selected from H, halo, Ci-2 haloalkyl, and -OR; or a pharmaceutically acceptable salt thereof.

1 6. The compound of any one of claims 1 -1 2, wherein R^Z4 is H or halo;

or a pharmaceutically acceptable salt thereof.

1 7. The compound of claim 1 , which is selected from the compounds of the

Examples in Table 1 .

1 8. A pharmaceutical composition, comprising a compound of any of the preceding claims admixed with at least one pharmaceutically acceptable carrier.

1 9. A method to treat a subject having a hepatitis B infection, which comprises administering to the subject a compound of any of claims 1 -1 7 or a pharmaceutical composition of claim 1 7.

20. The method of claim 1 9, wherein the compound of any one of claims 1 -1 7 or the pharmaceutical composition of claim 1 8 is used in combination with an additional therapeutic agent selected from an interferon or peginterferon, an HBV polymerase inhibitor, a viral entry inhibitor, a viral maturation inhibitor, a capsid assembly inhibitor, an HBV core modulator, a reverse transcriptase inhibitor, a TLR-agonist, or an immunomodulator.

21 . A method to inhibit replication of hepatitis B virus, which comprises contacting the hepatitis B virus, either in vitro or in vivo, with a compound according to any one of claims 1 -1 7.

22. A pharmaceutical combination, comprising a compound of any of claims 1 -17 and at least one additional therapeutic agent.

23. A compound according to any of claims 1 -1 7 for use in therapy.

24. The compound according to claim 23 wherein the therapy is treatment of a bacterial infection.

25. Use of a compound according to any one of claims 1 -17 in the manufacture of a medicament.