A compound of formula or a pharmaceutically acceptable salt thereof wherein R 1 is C 1 -C 3 alkyl; R 2 is hydrogen; R 3 is -C NR 8 R 9; R 8 and R 9 are chosen from one of the following groups: (i) R 8 and R 9 are both H; (ii) R 8 is H and R 9 is C 1 -C 3 alkylene-C O-C 1 -C 3 alkyl or OH; and (iii) R 8 is C 1 -C 3 alkylene-aryl and R 9 is C 1 -C 3 alkylene-C -C 1 -C 3 alkyl; R 10 is phenyl, wherein R 10 is substituted with 1 to 3 substituents designated as R 40, R 41, and R 42 and independently selected from the group consisting of: NO 2, NR 20 R 22, halo, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, -O-C 1 -C 6 alkyl, -O-C 1 -C 6 haloalkyl, C 1 -C 3 alkylene-OH, C 1 -C 3 alkylene-C OH, C 1 -C 3 alkylene-C O-C 1 -C 4 alkyl, C 2 -C 3 alkenylene-O-C 1 -C 3 alkyl, -NHC -C 1 -C 3 alkyl, - NH-SO 2 -C 1 -C 3 alkyl, -NH-SO 2 -C 1 -C 3 haloalkyl, -SO 2 -NH 2, -C -NR 20 R 22, and -L-R 12, wherein L is absent or is -C 1 -C 3 alkylene-, -C 2 -C 3 alkenylene-, -NH-, -NH-C 1 -C 3 alkylene-, -NR 26 -, -NHS 2 -, NHS 2 -C 1 -C 3 alkylene-, -NH-C -C 1 -C 3 alkylene-, -C -, -C -NH-C 1 -C 3 alkylene-, and -O-; R 12 is selected from the group consisting of: C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 3 -C 10 cycloalkyl, 3 to 8 membered heterocycloalkyl, 5 to 12 membered heteroaryl, and aryl, which may be substituted with one, two, or three substituents designated R 15, R 16, and R 17, R 15, R 16, and R 17 are independently selected from the group consisting of: OH, CN, halo, C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, -O-C 1 -C 3 alkyl, -O-C 1 -C 3 haloalkyl, -C 1 -C 3 alkylene-OH, -C 1 -C 3 alkylene-C O-C 1 -C 3 alkyl, - C -C 1 -C 4 alkyl, -C OC 1 -C 4 alkyl, -C NH-C 1 -C 3 alkylene-NR 30 R 32, -C NR 30 R 32, -O-C 1 -C 4 alkyl-NR 30 N 32, -NR 30 R 32, - NHC O-C 1 -C 4 alkyl, -NH-S 2 -C 1 -C 3 alkyl, -NH-S 2 -C 1 -C 3 haloalkyl, -S 2 -C 1 -C 3 alkyl, aryl, -O-aryl, -C 1 -C 3 alkylene-aryl, C 3 -C 6 cycloalkyl, heterocycloalkyl, -C 1 -C 3 alkylene-heterocycloalkyl, -C -heterocycloalkyl, 5 to 12 membered heteroaryl, and -C NH-C 1 -C 3 alkylene-heteroaryl, wherein said heterocycloalkyl, heteroaryl or aryl groups on R 15, R 16, and R 17 may be independently substituted with 1 to 3 substituents selected from the group consisting of: C 1 -C 3 -alkyl, C 1 -C 3 -haloalkyl, -O-C 1 -C 3 -alkyl, - O-C 1 -C 3 -haloalkyl, halo, -NH-S 2 -C 1 -C 3 alkyl, -NH-S 2 -C 1 -C 3 haloalkyl, and -S 2 -C 1 -C 3 alkyl; R 26 is C 1 -C 3 alkylene-C 3 -C 6 cycloalkyl; R 20 and R 22 are independently selected from the group consisting of H and C 1 -C 6 alkyl; and R 30 and R 32 are independently selected from the group consisting of H and C 1 -C 4 alkyl. R 1 is C 1 -C 3 alkyl; R 2 is hydrogen; R 3 is -C NR 8 R 9; R 8 and R 9 are chosen from one of the following groups: (i) R 8 and R 9 are both H; (ii) R 8 is H and R 9 is C 1 -C 3 alkylene-C O-C 1 -C 3 alkyl or OH; and (iii) R 8 is C 1 -C 3 alkylene-aryl and R 9 is C 1 -C 3 alkylene-C -C 1 -C 3 alkyl; (i) R 8 and R 9 are both H; (ii) R 8 is H and R 9 is C 1 -C 3 alkylene-C O-C 1 -C 3 alkyl or OH; and (iii) R 8 is C 1 -C 3 alkylene-aryl and R 9 is C 1 -C 3 alkylene-C -C 1 -C 3 alkyl; R 10 is phenyl, wherein R 10 is substituted with 1 to 3 substituents designated as R 40, R 41, and R 42 and independently selected from the group consisting of: NO 2, NR 20 R 22, halo, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, -O-C 1 -C 6 alkyl, -O-C 1 -C 6 haloalkyl, C 1 -C 3 alkylene-OH, C 1 -C 3 alkylene-C OH, C 1 -C 3 alkylene-C O-C 1 -C 4 alkyl, C 2 -C 3 alkenylene-O-C 1 -C 3 alkyl, -NHC -C 1 -C 3 alkyl, - NH-SO 2 -C 1 -C 3 alkyl, -NH-SO 2 -C 1 -C 3 haloalkyl, -SO 2 -NH 2, -C -NR 20 R 22, and -L-R 12, wherein L is absent or is -C 1 -C 3 alkylene-, -C 2 -C 3 alkenylene-, -NH-, -NH-C 1 -C 3 alkylene-, -NR 26 -, -NHS 2 -, NHS 2 -C 1 -C 3 alkylene-, -NH-C -C 1 -C 3 alkylene-, -C -, -C -NH-C 1 -C 3 alkylene-, and -O-; R 12 is selected from the group consisting of: C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 3 -C 10 cycloalkyl, 3 to 8 membered heterocycloalkyl, 5 to 12 membered heteroaryl, and aryl, which may be substituted with one, two, or three substituents designated R 15, R 16, and R 17, R 15, R 16, and R 17 are independently selected from the group consisting of: OH, CN, halo, C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, -O-C 1 -C 3 alkyl, -O-C 1 -C 3 haloalkyl, -C 1 -C 3 alkylene-OH, -C 1 -C 3 alkylene-C O-C 1 -C 3 alkyl, - C -C 1 -C 4 alkyl, -C OC 1 -C 4 alkyl, -C NH-C 1 -C 3 alkylene-NR 30 R 32, -C NR 30 R 32, -O-C 1 -C 4 alkyl-NR 30 N 32, -NR 30 R 32, - NHC O-C 1 -C 4 alkyl, -NH-S 2 -C 1 -C 3 alkyl, -NH-S 2 -C 1 -C 3 haloalkyl, -S 2 -C 1 -C 3 alkyl, aryl, -O-aryl, -C 1 -C 3 alkylene-aryl, C 3 -C 6 cycloalkyl, heterocycloalkyl, -C 1 -C 3 alkylene-heterocycloalkyl, -C -heterocycloalkyl, 5 to 12 membered heteroaryl, and -C NH-C 1 -C 3 alkylene-heteroaryl, wherein said heterocycloalkyl, heteroaryl or aryl groups on R 15, R 16, and R 17 may be independently substituted with 1 to 3 substituents selected from the group consisting of: C 1 -C 3 -alkyl, C 1 -C 3 -haloalkyl, -O-C 1 -C 3 -alkyl, - O-C 1 -C 3 -haloalkyl, halo, -NH-S 2 -C 1 -C 3 alkyl, -NH-S 2 -C 1 -C 3 haloalkyl, and -S 2 -C 1 -C 3 alkyl; R 26 is C 1 -C 3 alkylene-C 3 -C 6 cycloalkyl; R 20 and R 22 are independently selected from the group consisting of H and C 1 -C 6 alkyl; and R 30 and R 32 are independently selected from the group consisting of H and C 1 -C 4 alkyl.