Patent ID: 8907086

Claim:
A compound of structural formula I: or a pharmaceutically acceptable salt thereof; wherein X 1 and X 2 are independently selected from the group consisting of —N— and —CR 5 —; R 1 is selected from the group consisting of hydrogen, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, aryl, heterocycle, aroyl, heteroaroyl and C 3 -C 10 cycloalkyl; wherein the C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, aryl, heterocycle, aroyl, heteroaroyl and C 3 -C 10 cycloalkyl are unsubstituted or substituted with 1-3 substituents from R 5 ; R 2 is selected from the group consisting of C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, benzyl, heterocycle and C 1 -C 6 alkylheterocycle; wherein the C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, benzyl, heterocycle and C 1 -C 6 alkylheterocycle are unsubstituted or substituted with 1-3 substituents each independently selected from R 3 , R 4 and R 5 ; R 3 is selected from the group consisting of hydrogen, C 1 -C 6 alkyl and aryl, wherein the C 1 -C 6 alkyl and aryl are unsubstituted or substituted with 1-3 substituents selected from R 5 ; R 4 is selected from the group consisting of hydrogen and C 1 -C 6 alkyl; R 5 is selected from the group consisting of hydrogen, halogen, C 1 -C 6 alkyl, halogen-substitutedC 1 -C 6 alkyl, —OH, C 1 -C 6 alkylOH, halogen-substitutedC 1 -C 6 alkylOH, —OC 1 -C 6 alkyl, —Ohalogen-substitutedC 1 -C 6 alkyl, —COOH, —COOC 1 -C 6 alkyl, —C 1 -C 6 alkylCOOC 1 -C 6 alkyl, —C 1 -C 6 alkylCOOH, —CN, C 1 -C 6 alkylCN, NHC 1 -C 6 alkyl, N(C 1 -C 6 alkyl) 2 , C 1 -C 6 alkylCONH 2 , —CONH 2 , —CONHC 1 -C 6 alkyl, —NHCOC 1 -C 6 alkyl, —CON(C 1 -C 6 alkyl) 2 , —NHSO 2 C 1 -C 6 alkyl, SO 2 aryl, —SO 2 C 1 -C 6 alkyl, C 1 -C 6 alkylSO 2 C 1 -C 6 alkyl, aryl, —NHCOaryl, and —NHCOheterocycle; and n is 0-4.