Cysteine protease inhibitors for the treatment of parasitic disease

A compound of the formula:

• wherein R1 is aryl or heteroaryl optionally substituted with one, two or three substituents independently selected from C1-6 alkyl, —COOR5, halo, haloalkyl, cyano, aryl, heteroaryl or —SOm(C1-6 alkyl);
• R2 is C1-6 alkyl, C3-6 cycloalkyl wherein said alkyl group is optionally substituted with C3-6 cycloalkyl or one to six halo;
• R3 is C1-6 alkyl substituted with one to six halo;
• R4 is halo, aryl, heteroaryl, arylalkyl, heteroarylalkyl or heterocyclyl wherein said R4 aryl, R4 heteroaryl, R4 arylalkyl or R4 heteroarylalkyl groups are optionally substituted with one, two, or three substituents independently selected from halo, C1-6 alkyl, C1-6 haloalkyl, C1-6 hydroxyalkyl, C1-6 halo hydroxyalkyl, alkoxy, haloalkoxy, cyano, aryl, aryl-SO2CH3, heteroaryl, arylalkyl, heteroarylalkyl, heterocyclyl, —SOm(C1-6 alkyl), —SO2NR6R7, —COOR5, —CONR6R7 and C3-6 cycloalkyl-R8;
• R5 is hydrogen or C1-6 alkyl;
• R6 is hydrogen, C1-6 alkyl, C2-C6 alkene, (C1-6 alkyl)aryl, C1-6 hydroxyalkyl, —O(C1-6 alkyl), hydroxyl, aryl, heteroaryl, C3-8 cycloalkyl, heterocyclyl, C1-6 alkyl-COOR5, C0-6 alkyl-C(O)NH2, wherein said alkyl, aryl, heteroalkyl, C3-8 cycloalkyl and heterocyclyl can be optionally substituted on either the carbon or the heteroatom with one, two or three substituents independently selected from C1-6 alkyl or halo;
• R7 is hydrogen, C1-6 alkyl, (C1-6 alkyl)aryl, C1-6 hydroxyalkyl, —O(C1-6 alkyl), hydroxyl, aryl, heteroaryl, C3-8 cycloalkyl, heterocyclyl, wherein said alkyl, aryl, heteroaryl, C3-8 cycloalkyl and heterocyclyl can be optionally substituted on either the carbon or the heteroatom with one, two, or three substituents independently selected from C1-6 alkyl or halo;
• R6 and R7 can be taken together with the nitrogen atom to which they are attached to form a C3-8 heterocyclyl ring wherein said 3-8 membered ring system may be optionally substituted with one or two substituents independently selected from C1-6 alkyl and halo;
• R8 is either H, C1-6 alkyl, C1-6 haloalkyl, C1-6 hydroxyalkyl, C1-6 halo hydroxyalkyl, alkoxy, haloalkoxy, cyano, heteroaryl, arylalkyl, heteroarylalkyl, heterocyclyl, —SO2CH3, —SO2NR6R7, —SOm(C1-6 alkyl), —COOR5 or —CONR6R7;
• wherein m is an integer from zero to two;
• or a pharmaceutically acceptable salt or stereoisomer thereof.