A compound of formula wherein R 1 is selected from the group consisting of phenyl, 4-methoxyphenyl, 2-bromo-4-methoxyphenyl, and 3-fluoro-4-methoxyphenyl; R2 is hydrogen, or R 1 and R 2 may be linked together to form a carbocyclic ring having from four to nine ring carbon atoms, wherein said carbocyclic ring is optionally substituted with one or more (a) halogen, (b) -C 1-6 alkyl, or (c) -OC 1-6 alkyl; R3 is selected from the group consisting of benzyl, -(CH 2) naphthyl, -(CH 2) heteroaryl, wherein said heteroaryl is pyridyl or thienyl; wherein the aryl or heteroaryl moiety is optionally substituted with one or more (a) halo, (b) -NO 2, (c) -CN, (d) -C 1-6 alkyl, (e) -C 2-6 alkenyl, (f) -C 3-6 cycloalkyl, (g) -O-C 1-6 alkyl, (h) aryl, or (i) heteroaryl, wherein said alkyl, aryl or heteroaryl moiety is optionally substituted with one or more halo, -C 1-6 alkyl, wherein said alkyl is optionally substituted with one or more fluoro, -O-C 1-6 alkyl, wherein said alkyl is optionally substituted with one or more fluoro, -NSO 2 R 9, or OH; R4 is hydrogen; R 5 is -C 1-6 alkyl, wherein said alkyl is optionally substituted with one or more (a) halogen (b) hydroxyl, (c) -C 6-10 aryl, (d) heteroaryl, wherein said heteroaryl is an aromatic cyclic group having 5 to 12 ring atoms, at least one of which is O, N or S, (e) a heterocyclic group having 4 to 8 ring atoms, wherein at least one ring atom is a heteroatom selected from the group consisting of nitrogen, sulfur and oxygen, (f) -OC 1-4 alkyl, (g) -CN, or (h) -C(=O)-OR 9, wherein said alkyl, aryl, heteroaryl or heterocyclic group is optionally substituted with one or more hydroxy, fluoro, -C 1-4 alkyl, optionally substituted by fluoro, -OC 1-4 alkyl, -(CH 2) n -C 6-10 aryl, heteroaryl, or -C(=O)OR 9; R9 is selected from the group consisting of: hydrogen, C 1-4 alkyl, or -C 3-8 cycloalkyl, n is 0 or 1; or a pharmaceutically acceptable salt thereof (a) halogen, (b) -C 1-6 alkyl, or (c) -OC 1-6 alkyl; benzyl, -(CH 2) naphthyl, -(CH 2) heteroaryl, wherein said heteroaryl is pyridyl or thienyl; wherein the aryl or heteroaryl moiety is optionally substituted with one or more (a) halo, (b) -NO 2, (c) -CN, (d) -C 1-6 alkyl, (e) -C 2-6 alkenyl, (f) -C 3-6 cycloalkyl, (g) -O-C 1-6 alkyl, (h) aryl, or (i) heteroaryl, wherein said alkyl, aryl or heteroaryl moiety is optionally substituted with one or more halo, -C 1-6 alkyl, wherein said alkyl is optionally substituted with one or more fluoro, -O-C 1-6 alkyl, wherein said alkyl is optionally substituted with one or more fluoro, -NSO 2 R 9, or OH; R4 is hydrogen; R 5 is -C 1-6 alkyl, wherein said alkyl is optionally substituted with one or more (a) halogen (b) hydroxyl, (c) -C 6-10 aryl, (d) heteroaryl, wherein said heteroaryl is an aromatic cyclic group having 5 to 12 ring atoms, at least one of which is O, N or S, (e) a heterocyclic group having 4 to 8 ring atoms, wherein at least one ring atom is a heteroatom selected from the group consisting of nitrogen, sulfur and oxygen, (f) -OC 1-4 alkyl, (g) -CN, or (h) -C(=O)-OR 9, wherein said alkyl, aryl, heteroaryl or heterocyclic group is optionally substituted with one or more hydroxy, fluoro, -C 1-4 alkyl, optionally substituted by fluoro, -OC 1-4 alkyl, -(CH 2) n -C 6-10 aryl, heteroaryl, or -C(=O)OR 9; R9 is selected from the group consisting of: hydrogen, C 1-4 alkyl, or -C 3-8 cycloalkyl, (a) halo, (b) -NO 2, (c) -CN, (d) -C 1-6 alkyl, (e) -C 2-6 alkenyl, (f) -C 3-6 cycloalkyl, (g) -O-C 1-6 alkyl, (h) aryl, or (i) heteroaryl, wherein said alkyl, aryl or heteroaryl moiety is optionally substituted with one or more halo, -C 1-6 alkyl, wherein said alkyl is optionally substituted with one or more fluoro, -O-C 1-6 alkyl, wherein said alkyl is optionally substituted with one or more fluoro, -NSO 2 R 9, or OH; halo, -C 1-6 alkyl, wherein said alkyl is optionally substituted with one or more fluoro, -O-C 1-6 alkyl, wherein said alkyl is optionally substituted with one or more fluoro, -NSO 2 R 9, or OH; (a) halogen (b) hydroxyl, (c) -C 6-10 aryl, (d) heteroaryl, wherein said heteroaryl is an aromatic cyclic group having 5 to 12 ring atoms, at least one of which is O, N or S, (e) a heterocyclic group having 4 to 8 ring atoms, wherein at least one ring atom is a heteroatom selected from the group consisting of nitrogen, sulfur and oxygen, (f) -OC 1-4 alkyl, (g) -CN, or (h) -C(=O)-OR 9, wherein said alkyl, aryl, heteroaryl or heterocyclic group is optionally substituted with one or more hydroxy, fluoro, -C 1-4 alkyl, optionally substituted by fluoro, -OC 1-4 alkyl, -(CH 2) n -C 6-10 aryl, heteroaryl, or -C(=O)OR 9; hydroxy, fluoro, -C 1-4 alkyl, optionally substituted by fluoro, -OC 1-4 alkyl, -(CH 2) n -C 6-10 aryl, heteroaryl, or -C(=O)OR 9; hydrogen, C 1-4 alkyl, or -C 3-8 cycloalkyl,