Patent ID: 6903111

Claim:
A compound of formula (I) or a pharmaceutically acceptable salt, wherein, A 1 represents methylene or carbonyl, R 1 represents hydrogen or methyl group, R 2 represents —(CH 2 ) n -A 2 -Ph, wherein n denotes an integer of 0-3 and A 2 is single bond or —O—, R 3 represents —COOH, —COOR 4 , —COSR 4 , —CONHR 5 , —NHR 6 , —P(O) (OPri) 2 , —CH(R 9 )COOH, —CH 2 CH(COOH) 2 , —SO 3 H, or a following formula: wherein, R 4 represents lower alkyl, non-substituted phenyl group, or phenyl group which is substituted with lower alkyl, lower alkoxy, hydroxy, methoxycarbonyl, ethoxycarbonyl, trifluoromethanesulfoneamide or halogen, R 5 represents pyridyl, thiazolyl, non-substituted phenyl group, or phenyl group which is substituted with lower alkyl, lower alkoxy, hydroxy, trifluoromethanesulfoneamide or halogen, R 6 represents —SO 2 —R 7 or —CO—(CH 2 ) m -R 8 , wherein, R 7 , represents lower alkyl, —CH 2 COOH, trifluoromethyl, non-substituted phenyl, or phenyl group which is substituted with lower alkyl, lower alkoxy, hydroxy or halogen, R 8 represents carboxyl group, non-substituted phenyl, or phenyl group which is substituted with lower alkyl, lower alkoxy, carboxyl, hydroxy, halogen, —NHSO 2 CF 3 or —NHCOCOOH, m=0 or 1, R 9 represents hydrogen, hydroxy or —OR 10 wherein R 10 is lower alkyl, —CH 2 OCH 3 , —CH 2 O(CH 2 ) 2 OCH 3 or —CH 2 SCH 3 , A 3 is hydrogen or methyl.