Cathepsin cysteine protease inhibitors

1. A compound of the formula:

wherein R 1 is hydrogen, C 1-6 alkyl or C 2-6 alkenyl wherein said alkyl and alkenyl groups are optionally substituted with one to six halo, C 3-6 cycloalkyl, —SR 7 , —SOR 7 , —SO 2 R 7 , —SO 2 CH(R a )(R b ), —OR 7 , —N(R 7 ) 2 , aryl, heteroaryl or heterocyclyl wherein said aryl, heteroaryl and heterocyclyl groups are optionally substituted with one or two substitutents independently selected from C 1-6 alkyl, halo, hydroxyalkyl, hydroxy, alkoxy or keto;

R 2 is hydrogen, C 1-6 alkyl or C 2-6 alkenyl wherein said alkyl and alkenyl groups are optionally substituted with one to six halo, C 3-6 cycloalkyl, —SR 7 , —SOR 7 , —SO 2 R 7 ,-—SO 2 CH(R a )(R b ), —OR 7 , —N(R 7 ) 2 , aryl, heteroaryl or heterocyclyl wherein said aryl, heteroaryl and heterocyclyl groups are optionally substituted with one or two substitutents independently selected from C 1-6 alkyl, halo, hydroxyalkyl, hydroxy, alkoxy or keto;

or R 1 and R 2 can be taken together with the carbon atom to which they are attached to form a C 3-8 cycloalkyl or heterocyclyl ring wherein said ring system is optionally substituted with one or two substituents independently selected from C 1-6 alkyl, hydroxyalkyl, haloalkyl or halo;

R 3 is C 1-6 alkyl or C 2-6 alkenyl, wherein said alkyl and alkenyl groups are optionally substituted with C 3-6 cycloalkyl or one to six halo;

R 4 is C 1-6 alkyl substituted with 1-6 halo;

R 5 is selected from hydrogen or C 1-3 alkyl;

D is aryl or heteroaryl, wherein said aryl or heteroaryl group, which may be monocyclic or bicyclic, is optionally substituted on either the carbon or the heteroatom with one to five substituents independently selected from C 1-6 alkyl, haloalkyl, halo, keto, alkoxy, —SR 7 , —OR 7 , N(R 7 ) 2 , —SO 2 R 7 or —SO 2 R a ;

E is aryl or heteroaryl, wherein said aryl or heteroaryl group, which may be monocyclic or bicyclic, is optionally substituted on either the carbon or the heteroatom with one to five substituents independently selected from C 1-6 alkyl, haloalkyl, halo, keto, alkoxy, —SR 7 , —OR 7 , N(R 7 ) 2 or —SO 2 R 7 ;

X is CR a R b or cyclopropyl;

R 7 is selected from hydrogen, C 1-6 alkyl, aryl, aryl(C 1-4 )alkyl, heteroaryl, heteroaryl(C 1-4 ) alkyl, C 3-8 cycloalkyl, C 3-8 cycloalkyl(C 1-4 )alkyl, and heterocyclyl (C 1-4 )alkyl wherein said groups can be optionally substituted with one, two, or three substituents independently selected from halo, alkoxy, cyano, —NR a R b , —SR a or —SO m R a ;

R 6 is selected hydrogen, C 1-6 alkyl, C 3-8 cycloalkyl, heterocyclyl, heteroaryl, cyano, halo, alkoxy, OR a , —NR a , —SR a or —SO m R 5 ; wherein said alkyl, cycloalkyl, heterocyclyl and heteroaryl groups can be optionally substituted with one, two, or three substituents independently selected from halo, cyano or —OR a ;

R a is hydrogen or C 1-6 alkyl which is optionally substituted with one, two, or three substituents independently selected from halo or —OR 5 ;

R b is hydrogen or C 1-6 alkyl which is optionally substituted with one, two, or three substituents independently selected from halo or —OR 5 ;

m is an integer from zero to two;

or a pharmaceutically acceptable salt or stereoisomer thereof.

2. The compound of claim 1 wherein R 1 is hydrogen, R 2 is hydrogen, or R 1 and R 2 can be taken together with the carbon atom to which they are attached to form a C 3-8 cycloalkyl ring.

3. The compound of claim 2 wherein R 3 is C 1-6 alkyl optionally substituted with one to six halo.

4. The compound of claim 3 wherein D is aryl.

5. The compound of claim 4 wherein D is phenyl.

6. The compound of claim 1 wherein X is cyclopropyl.

7. The compound selected from:

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{1-[(cyclopropylamino)carbonyl]cyclopropyl}-2′-fluorobiphenyl-4-yl)-2,2,2-trifluoroethyl]-4-fluoro-L-leucinamide;

N 2 -[(1S)-1-(4-{5-[1-(aminocarbonyl)cyclopropyl]pyridin-2-yl}phenyl)-2,2,2-trifluoroethyl]-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[1-(aminocarbonyl)cyclopropyl]biphenyl-4-yl}-2,2-difluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{[(1R,2R)-2-[(cyclopropylamino)carbonyl]cyclopropyl}biphenyl-4-yl)-2,2-difluoroethyl]-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{1-[(cyclopropylamino)carbonyl]cyclopropyl}biphenyl -4-yl)-2,2-difluoroethyl]-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[1-(azetidin-1-ylcarbonyl)cyclopropyl]biphenyl-4-yl}-2,2-difluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-2,2-difluoro-1-[4′-(1-{[(2,2,2-trifluoroethyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-4-fluoro-L -leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -((1S)-1-{4′-[2-(cyclopropylamino)-2-oxoethyl]biphenyl-4-yl}-2,2-difluoroethyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-2,2-difluoro-1-(4′-{1-[(isopropylamino)carbonyl]cyclopropyl}biphenyl-4-yl)ethyl]-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-2,2-difluoro-1-(4′-{1[(pyridin-3-ylamino)carbonyl]cyclopropyl}biphenyl-4-yl)ethyl]-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-2,2-difluoro-1[4′-(1-{[(2- hydroxyethyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-2,2-difluoro-1[4′-(1-{[(1-methylcyclopropyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-2,2-difluoro-1-[4′-(1-{[(2,2,2-trifluoro-1- methylethyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-2,2-difluoro-1-[4′-(1-{[(2-fluorocyclopropyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-2,2-difluoro-1-(4′-{1-[(1,3-thiazol-2-ylamino)carbonyl]cyclopropyl}biphenyl-4-yl)ethyl]-4-fluoro-L-leucinamide;

N 2 -{(1S)-1-[4′-(2-amino-1,1-difluoro-2-oxoethyl)biphenyl-4-yl]-2,2,2-trifluoroethyl}-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{1-[(cyclopropylamino)carbonyl]cyclopropyl}biphenyl- 4-yl)-2,2,2-trifluoroethyl]-4-fluoro-L-leucinamide;

N 1 -(cyanomethyl)-N 2 -[(1S)-1-(4′-{1-[(cyclopropylamino)carbonyl]cyclopropyl}biphenyl-4-yl) -2,2,2-trifluoroethyl]-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[1-(aminocarbonyl)cyclopropyl]-2′-fluorobiphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{1-[(cyclopropylamino)carbonyl]cyclopropyl}biphenyl -4-yl)-2,2-difluoroethyl]-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-2,2-difluoro-1-[4′-(1-{[(2,2,2-trifluoroethyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-L-leucinamide;

N 2 -((1S)-1-{4′-[1-(aminocarbonyl)cyclopropyl]biphenyl-4-yl}-2,2-difluoroethyl)-N 1 -(1-cyanocyclopropyl)-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{1-[(cyclopropylamino)carbonyl]cyclobutyl}biphenyl -4-yl)-2,2,2-trifluoroethyl]-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[1-(aminocarbonyl)cyclobutyl]biphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 - (cyanomethyl)-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[1-(aminocarbonyl)cyclobutyl]biphenyl-4-yl}-2,2-difluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-1-[4′-(1-{[(1-cyanocyclopropyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]-2,2-difluoroethyl}-L -leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-2,2-difluoro-1-(4′-{1-[(methoxyamino)carbonyl]cyclopropyl}biphenyl-4-yl)ethyl]-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-2,2-difluoro-1-[4′-(1-{[methoxy(methyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-2,2-difluoro-1-[4′-(1-{[(2-hydroxyethyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{1-[(dimethylamino)carbonyl]cyclopropyl}biphenyl-4-yl)-2,2-difluoroethyl]-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{1-[(cyclobutylamino)carbonyl]cyclopropyl}biphenyl -4-yl)-2,2-difluoroethyl]-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -((1S)-2,2-difluoro-1-{4′-[1-(pyrrolidin-1-ylcarbonyl)cyclopropyl]biphenyl-4-yl}ethyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-2,2-difluoro-1-[4′-(1-{[methoxy(methyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-2,2-difluoro-1-[4′-(1-{[(2-methoxyethyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -((1S)-2,2-difluoro-1-{4′-[1-(morpholin-4-ylcarbonyl)cyclopropyl]biphenyl-4-yl}ethyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-2,2-difluoro-1-(4′-{1-[(methylamino)carbonyl]cyclopropyl}biphenyl-4-yl)ethyl]-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-1-[4′-(1-{[(cyclopropylmethyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]-2,2-difluoroethyl}-4-fluoro -L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-2,2-difluoro-1-(4′-{1-[(propylamino)carbonyl]cyclopropyl}biphenyl-4-yl)ethyl]-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[1-(aminocarbonyl)cyclopropyl]biphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-1-[4′-(1-{[(cyanomethyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]-2,2,2-trifluoroethyl}-4-fluoro-L -leucinamide;

N 1 -(1-cyanocyclopropyl)-4-fluoro-N 2 -{(1S)-2,2,2-trifluoro-1-[4′-(1-{[(methylsulfonyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-L-leucinamide;

N 2 -[(1S)-1-(4′-{1-[(tert-butylamino)carbonyl]cyclopropyl}biphenyl-4-yl)-2,2,2-trifluoroethyl]-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -((1S)-1-{4′-[2-(cyclopropylamino)-1,1-dimethyl-2-oxoethyl]biphenyl-4-yl}-2,2,2-trifluoroethyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{1-[(cyclopropylamino)carbonyl]cyclopropyl}-3′-fluorobiphenyl-4-yl)-2,2,2-trifluoroethyl]-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{1-[(cyclopropylamino)carbonyl]cyclopropyl}biphenyl -4-yl)-2,2,2-trifluoroethyl]-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{1-[(cyclopropylamino)carbonyl]cyclopropyl}-3′-fluorobiphenyl-4-yl)-2,2-difluoroethyl]-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -((1S)-1-{4′-[2-(cyclopropylamino)-1,1-dimethyl-2-oxoethyl]biphenyl-4-yl}-2,2-difluoroethyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -[(1S)-1-(4′-{1-[(cyclopropylamino)carbonyl]cyclopropyl}-2′-fluorobiphenyl-4-yl)-2,2-difluoroethyl]-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-4-fluoro-N 2 -{(1S)-2,2,2-trifluoro-1-[4′-(1-{[(2-fluorocyclopropyl)amino]carbonyl}cyclopropyl)biphenyl-4-yl]ethyl}-L-leucinamide;

N 2 -[(1S)-1-(4-{5-[1-(aminocarbonyl)cyclopropyl]-3-chloropyridin-2-yl}phenyl)-2,2,2-trifluoroethyl]-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -{(1S)-1-[4-(3-chloro-5-{1-[(cyclopropylamino)carbonyl]cyclopropyl}pyridin-2-yl)phenyl]-2,2,2-trifluoroethyl}-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 1 -(1-cyanocyclopropyl)-N 2 -{(1S)-1-[4-(5-{1-[(cyclopropylamino)carbonyl]cyclopropyl}pyridin-2-yl)phenyl]-2,2,2-trifluoroethyl}-4-fluoro -L-leucinamide;

N 2 -((1S)-1-{4′-[1-(aminocarbonyl)cyclopropyl]biphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(cyanomethyl)-4-fluoro-L-leucinamide;

N 2 -[(1S)-1-(4-{5-[1-(aminocarbonyl)cyclopropyl]pyridin-2-yl}phenyl)-2,2,2-trifluoroethyl]-N 1 -(cyanomethyl)-4-fluoro-L-leucinamide;

N 2 -{(1S)-1-[4′-(2-amino-1-methyl-2-oxoethyl)biphenyl-4-yl]-2,2,2-trifluoroethyl}-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[(1R)-2-amino-1-methyl-2-oxoethyl]biphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[(1S)-2-amino-1-methyl-2-oxoethyl]biphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -{(1S)-1-[4′-(2-amino-1methyl-2-oxoethyl)-2′-fluorobiphenyl-4-yl]-2,2,2-trifluoroethyl}-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4-[5-(2-amino-1-methyl-2-oxoethyl)pyridin-2-yl]phenyl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -{(1S)-1-[4′-(2-amino-1-methyl-2-oxoethyl)-2′-fluorobiphenyl-4-yl]-2,2-difluoroethyl}-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[(1R)-2-amino-1-methyl-2-oxoethyl]-2′-fluorobiphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[(1S)-2-amino-1-methyl-2-oxoethyl]-2′-fluorobiphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[(1S)-2-amino-1-methyl-2-oxoethyl]-2-bromobiphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[(1S)-2-amino-1-methyl-2-oxoethyl]biphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-5-hydroxy-L-leucinamide; 1-(4′-{(1S)-1-[((1S)-1-{[(1-cyanocyclopropyl)amino]carbonyl}-3,3,3-trifluoropropyl)amino]-2,2,2-trifluoroethyl}biphenyl-4-yl)cyclopropanecarboxamide;

N 2 -((1S)-1-{4′-[1-(aminocarbonyl)vinyl]biphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -((1S)-1-{4′-[1-(aminocarbonyl)cyclopropyl]biphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-L-norvalinamide;

N 2 -((1S)-1-{4′-[1-(2-amino-2-oxoethyl)cyclopropyl]biphenyl-4-yl}-2,2,2-trifluoroethyl)-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -{(1S)-1-[4′-(3-amino-2,2-dimethyl-3-oxopropyl)biphenyl-4-yl]-2,2,2-trifluoroethyl}-N 1 -(1- cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -{(1S)-1-[4′-(2-amino-2-oxoethyl)-2′-fluorobiphenyl-4-yl]-2,2,2-trifluoroethyl}-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

N 2 -{(1S)-1-[4′-(2-amino-2-oxoethyl)biphenyl-4-yl]-2,2,2-trifluoroethyl}-N 1 -(1-cyanocyclopropyl)-4-fluoro-L-leucinamide;

or a pharmaceutically acceptable salt or stereoisomer thereof.

8. A pharmaceutical composition comprising a compound according to claim 1 and a pharmaceutically acceptable carrier.

9. A pharmaceutical composition comprising a compound of claim 1 and another agent selected from the group consisting of: an organic bisphosphonate, an estrogen receptor modulator, an estrogen receptor beta modulator, an androgen receptor modulator, an inhibitor of osteoclast proton ATPase, an inhibitor of HMG-CoA reductase, an integrin receptor antagonist, or an osteoblast anabolic agent, and the pharmaceutically acceptable salts and mixtures thereof.