Patent ID: 6906089

Claim:
A compound of formula (I) or a pharmaceutically acceptable salt thereof: wherein R 1 is naphthyl, or phenyl optionally substituted with one or more substituents selected from the group consisting of halo, —O—C 1-6 alkyl, —S—C 1-6 alkyl, C 1-6 alkyl, C 1-6 haloakyl, —O—(CH 2 ) n -Ph, —S—(CH 2 ) n -Ph, cyano, phenyl, and CO 2 R, wherein R is hydrogen or C 1-6 alkyl, and n is 0, 1, 2 or 3; or R 1 is phenyl fused with an aromatic or non-aromatic cyclic ring of 5-7 members wherein said cyclic ring optionally contains up to three heteroatoms, independently selected from N, O and S; R 2 is H, C 1-6 alkyl, C 1-6 alkoxy, phenyl, NH(CH 2 ) n -Ph, NH—C 1-6 alkyl, halo or alkoxy; R 3 is COOH, tetrazole, CN, NO 2 , OH, —S—C 1-6 alkyl, —SO—C 1-6 alkyl, —O—C 1-6 alkyl, SONH 2 , CHO, CH 2 OH, (CH 2 ) n NH 2 , CONHOR′, O(CH 2 ) n CO 2 R′, O(CH 2 ) n CONHR′, CONHR′, (CH 2 ) n CO 2 R′, or (CH 2 ) n CONHR′ wherein R′ is hydrogen or C 1-6 alkyl, and n is 0, 1, 2 or 3; and one of X 1 and X 2 is N or CR″, and the other is NR″ or CHR″ wherein R″ is hydrogen, C 1-6 alkyl, or C 3-7 cycloalkyl; or when one of X 1 and X 2 is N or CR″ then the other may be S or O; provided that the compound is not one in which R 1 is naphthyl, or phenyl optionally substituted with one or more substituents selected from the group consisting of halo, —O—C 1-6 alkyl, —S—C 1-6 alkyl, C 1-6 alkyl, —O—(CH 2 ) n -Ph, —S—(CH 2 ) n -Ph, cyano, phenyl, and CO 2 R, wherein R is hydrogen or C 1-6 alkyl and n is 0, 1, 2 or 3; or R 1 is phenyl fused with an aromatic or non-aromatic cyclic ring of 5-7 members wherein said cyclic ring optionally contains up to two heteroatoms, independently selected from N, O and S; and R 2 is H, NH(CH 2 ) n -Ph or NH—C 1-6 alkyl; and and R 3 is CO 2 H, CONH 2 , CN, NO 2 , C 1-6 alkylthio, SO 2 —C 1-6 alkyl, C 1-6 alkoxy, SONH 2 , CONHOH, NH 2 , CHO, CH 2 OH, CH 2 NH 2 , or CO 2 R, wherein R is hydrogen or C 1-6 alkyl.