Substituted cyclobutylbenzene compounds as indoleamine 2,3-dioxygenase (IDO) inhibitors

1. A compound of formula (Ib), or a pharmaceutically acceptable salt thereof:

wherein:

R 1 is selected from:

(1) C 3-6 cycloalkyl, optionally substituted with 1-3 substituents independently selected from (a) halogen, (b) —O—C 1-6 alkyl and (c) C 1-6 alkyl optionally substituted with 1-3 halogens,

(2) phenyl, optionally substituted with 1-3 substituents independently selected from (a) halogen, (b) —CN, (c) —O—C 1-6 alkyl and (d) C 1-6 alkyl optionally substituted with 1-3 halogens,

(3) a bicyclic ring comprising a phenyl fused to a C 4-7 cycloalkyl, wherein the bicyclic ring is optionally substituted with halogen or C 1-6 alkyl, and

(4) a heterocyclyl selected from (a) a saturated 4-7 membered monocyclic heterocyclyl, (b) a partially unsaturated 4-7 membered monocyclic heterocyclyl, (c) an aromatic 4-7 membered monocyclic heterocyclyl, and (d) a 6-9 membered fused bicyclic ring containing one or more heteroatoms selected from N, O, and S in either of the rings, wherein the heterocyclyl is optionally substituted with 1-3 substituents independently selected from (a) halogen, (b) —CN and (c) C 1-6 alkyl;

R 2 is selected from:

(1) C 1-6 alkyl, optionally substituted with 1-3 substituents independently selected from (a) halogen and (b) C 3-6 cycloalkyl,

(2) C 3-6 cycloalkyl, optionally substituted with 1-3 substituents independently selected from (a) halogen and (b) C 1-6 alkyl optionally substituted with NH 2 ,

(3) phenyl, optionally substituted with 1-3 substituents independently selected from (a) halogen and (b) C 1-6 alkyl,

(4) a bicyclic ring comprising a phenyl fused to a C 4-7 cycloalkyl, optionally substituted with halogen or C 1-6 alkyl,

(5) S(O) 2 -aryl, and

(6) a heterocyclyl selected from (a) a saturated 4-7 membered monocyclic heterocyclyl, (b) a partially unsaturated 4-7 membered monocyclic heterocyclyl, and (c) an aromatic 4-7 membered monocyclic heterocyclyl, wherein the heterocyclyl is optionally substituted with 1-3 substituents independently selected from (a) halogen and (b) C 1-6 alkyl;

R 3 is selected from (1) H, (2) fluoro, (3) methyl, (4) ethyl, (5) —CH 3 —OH, and (6) —C═N—C(CH 3 ) 3 ; and

each of R 4 and R 5 is independently selected from (1) H, (2) halogen, (3) —OH, and (4) methyl.

2. A compound selected from the group consisting of, or a pharmaceutically acceptable salt thereof:

N-(4-(1-butyramidocyclobutyl)phenyl)-3-chlorobenzamide,

3-chloro-N-(4-(1-(4-cyanobenzamido)cyclobutyl)phenyl)benzamide,

N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)pyrazine-2-carboxamide,

3-chloro-N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)pyridine-2-carboxamide,

4-chloro-N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)pyridine-2-carboxamide,

N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)-1-methyl-1H-imidazole-2-carboxamide,

6-chloro-N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)pyridine-3-carboxamide,

4-chloro-N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)-3-fluorobenzamide,

5-chloro-N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)pyridine-2-carboxamide,

N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)-3,4-difluorobenzamide,

3,4-dichloro-N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)benzamide,

N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)-1,3-oxazole-2-carboxamide,

N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)-1-methyl-1H-pyrazole-3-carboxamide,

N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)-1,3-thiazole-4-carboxamide,

N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)-1,3-thiazole-2-carboxamide,

N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)-1,3-oxazole-4-carboxamide,

N-(4-{1-[(4-chlorobenzene-1-carbonyl)amino]cyclobutyl}phenyl)pyrimidine-5-carboxamide,

N-(1-{4-[(3-chlorobenzene-1-carbonyl)amino]phenyl}cyclobutyl)pyrimidine-5-carboxamide,

3-chloro-N-(4-(1-(4-chlorobenzamido)cyclobutyl)phenyl)benzamide,

3-chloro-N-(4-(1-((4-fluorophenyl)carbamoyl)cyclobutyl)phenyl)benzamide,

1-(4-(3-chlorobenzamido)phenyl)cyclobutane-1-carboxylic acid,

3-chloro-N-(4-{1-[(4-chlorophenyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(2,4-difluorophenyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(3,4-difluorophenyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(6-chloropyridin-3-yl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(5-fluoropyridin-2-yl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(6-fluoropyridin-3-yl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-{4-[1-(cyclohexylcarbamoyl)cyclobutyl]phenyl}benzamide,

3-chloro-N-(4-{1-[(2-ethylcyclopropyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-[4-(1-{[(1R,2R)-2-(trifluoromethyl)cyclopropyl]carbamoyl}cyclobutyl)phenyl]benzamide,

3-chloro-N-(4-{1-[(4,4-difluorocyclohexyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(oxan-4-yl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(1-methyl-1H-pyrazol-3-yl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(2-ethoxycyclopropyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-[4-(1-{[2-(difluoromethyl)cyclopropyl]carbamoyl}cyclobutyl)phenyl]benzamide,

3-chloro-N-(4-{1-[(3,3-difluorocyclobutyl)carbamoyl]cyclobutyl}phenyl)benzamide,

N-(4-{1-[(bicyclo[1.1.1]pentan-1-yl)carbamoyl]cyclobutyl}phenyl)-3-chlorobenzamide,

3-chloro-N-(4-{1-[(oxan-3-yl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(1-cyclopropylethyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(2,2-dimethyloxan-4-yl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-[4-(1-{[1-(oxolan-2-yl)ethyl]carbamoyl}cyclobutyl)phenyl]benzamide,

3-chloro-N-[4-(1-{[1-(2,2,2-trifluoroethyl)azetidin-3-yl]carbamoyl}cyclobutyl)phenyl]benzamide,

3-chloro-N-(4-(1-((2-ethoxypropyl)carbamoyl)cyclobutyl)phenyl)benzamide,

3-chloro-N-(4-{1-[(2-methylcyclopropyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(3,3,3-trifluoropropyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(cyclopropylmethyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-{1-[(2,2,2-trifluoroethyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-{4-[1-(ethylcarbamoyl)cyclobutyl]phenyl}benzamide,

3-chloro-N-[4-(1-{[(3S)-oxolan-3-yl]carbamoyl}cyclobutyl)phenyl]benzamide,

3-chloro-N-[4-(1-{[(3R)-oxolan-3-yl]carbamoyl}cyclobutyl)phenyl]benzamide,

3-chloro-N-(4-{1-[(phenylsulfonyl)carbamoyl]cyclobutyl}phenyl)benzamide,

5-methyl-N-(4-(1-(propylcarbamoyl)cyclobutyl)phenyl)-1,2,3-thiadiazole-4-carboxamide,

4-(aminomethyl)-N-{4-[1-(propylcarbamoyl)cyclobutyl]phenyl}benzamide,

3-methyl-N-{4-[1-(propylcarbamoyl)cyclobutyl]phenyl}-1,2-oxazole-5-carboxamide,

2-ethyl-N-{4-[1-(propylcarbamoyl)cyclobutyl]phenyl}-1,3-oxazole-4-carboxamide,

N-{4-[1-(propylcarbamoyl)cyclobutyl]phenyl}imidazo[1,2-b]pyridazine-2-carboxamide,

N-(3-chloro-2-fluorophenyl)-4-(1-((5-fluoropyridin-2-yl)carbamoyl)cyclobutyl)benzamide,

N-cyclohexyl-4-{1-[(5-fluoropyridin-2-yl)carbamoyl]cyclobutyl}benzamide,

N-(4,4-difluorocyclohexyl)-4-{1-[(5-fluoropyridin-2-yl)carbamoyl]cyclobutyl}benzamide,

3-chloro-N-(4-(3-fluoro-1-((4-fluorophenyl)carbamoyl)cyclobutyl)phenyl)benzamide,

3-chloro-N-(4-(3,3-difluoro-1-((4-fluorophenyl)carbamoyl)cyclobutyl)phenyl)benzamide,

3-chloro-N-[4-(1-{[(1S,2R)-2-ethoxycyclopropyl]carbamoyl}-3,3-difluorocyclobutyl)phenyl]benzamide,

3-chloro-N-(4-{1-[(2-ethoxycyclopropyl)carbamoyl]-3,3-difluorocyclobutyl}phenyl)benzamide,

3-chloro-N-[4-(1-{[(1R,2S)-2-ethoxycyclopropyl]carbamoyl}-3,3-difluorocyclobutyl)phenyl]benzamide,

3-chloro-N-[4-(1-{[(1R,2R)-2-ethoxycyclopropyl]carbamoyl}-3,3-difluorocyclobutyl)phenyl]benzamide,

3-chloro-N-(4-{3,3-difluoro-1-[(3,3,3-trifluoropropyl)carbamoyl]cyclobutyl}phenyl)benzamide,

3-chloro-N-(4-((cis)-1-((4-fluorophenyl)carbamoyl)-3-hydroxycyclobutyl)phenyl)benzamide,

3-chloro-N-(4-((1r,3r)-1-((4-fluorophenyl)carbamoyl)-3-hydroxy-3-methylcyclobutyl)phenyl)benzamide,

N-(4-(3,3-difluoro-1-((4-fluorophenyl)carbamoyl)cyclobutyl)phenyl)-3-fluorobenzamide,

3-cyano-N-(4-{3,3-difluoro-1-[(4-fluorophenyl)carbamoyl]cyclobutyl}phenyl)benzamide,

4-chloro-N-(4-{3,3-difluoro-1-[(4-fluorophenyl)carbamoyl]cyclobutyl}phenyl)pyridine-2-carboxamide,

5-chloro-N-(4-{3,3-difluoro-1-[(4-fluorophenyl)carbamoyl]cyclobutyl}phenyl)pyridine-3-carboxamide,

N-(4-{3,3-difluoro-1-[(4-fluorophenyl)carbamoyl]cyclobutyl}phenyl)-2-(trifluoromethyl)pyridine-4-carboxamide,

4-fluoro-3-methyl-N-(4-(1-(propylcarbamoyl)cyclobutyl)phenyl)benzamide,

3-chloro-4-fluoro-N-{4-[1-(propylcarbamoyl)cyclobutyl]phenyl}benzamide,

3-chloro-5-fluoro-N-{4-[1-(propylcarbamoyl)cyclobutyl]phenyl}benzamide,

3,5-dichloro-N-{4-[1-(propylcarbamoyl)cyclobutyl]phenyl}benzamide,

3,4-dichloro-N-{4-[1-(propylcarbamoyl)cyclobutyl]phenyl}benzamide,

3-chloro-N-(2-fluoro-4-(1-((3,3,3-trifluoropropyl)carbamoyl)cyclobutyl)phenyl)benzamide,

3-chloro-N-(2-(hydroxymethyl)-4-(1-((3,3,3-trifluoropropyl)carbamoyl)cyclobutyl)phenyl)benzamide,

N-(2-[(E)-(tert-butylimino)methyl]-4-{1-[(3,3,3-trifluoropropyl)carbamoyl]cyclobutyl}phenyl)-3-chlorobenzamide,

3-chloro-N-(4-(1-((4-fluorobicyclo[4.2.0]octa-1(6),2,4-trien-7-yl)carbamoyl)cyclobutyl)phenyl)benzamide, and

N-{4-[1-(propylcarbamoyl)cyclobutyl]phenyl}bicyclo[4.2.0]octa-1,3,5-triene-7-carboxamide.

3. A composition which comprises an inert carrier and a compound of claim 1 or a pharmaceutically acceptable salt thereof.

4. A method for treating an IDO-associated disease or disorder in a mammalian subject which comprises administering to the subject an effective amount of a compound of claim 1 or a pharmaceutically acceptable salt thereof.

5. A method for treating an IDO-associated disease or disorder in a mammalian subject which comprises administering to the subject an effective amount of a compound of claim 1 or a pharmaceutically acceptable salt thereof in combination with another anti-cancer agent.

6. The method of any of claim 4 , wherein the IDO-associated disease or disorder is a cancer, viral infection, HCV infection, depression, neurodegenerative disorders, trauma, age-related cataracts, organ transplantation, and autoimmune diseases.

7. The method of claim 6 , wherein the cancer is selected from a cancer of the colon, pancreas, breast, prostate, lung, brain, ovary, cervix, testes, renal, head and neck, lymphoma, leukemia, and melanoma.