Patent ID: 7598254

Claim:
Compounds of the following formula (I) or salts thereof in which R 1 represents an aryl group having 6-10 carbon atoms or a hetero-aryl group which may have a substituent selected from the group consisting of an alkyl group having 1-8 carbon atoms, a halogen-substituted alkyl group having 1-8 carbon atoms, an alkoxy group having 1-8 carbon atoms, an alkoxy group having 1-8 carbon atoms which is substituted with an alkoxy group having 1-8 carbon atoms, an alkoxycarbonyl group having 2-8 carbon atoms, formyl, carboxyl, halogen, hydroxyl, nitro, cyano, amino, an aryl group having 6-10 carbon atoms, and an aryloxy group having 6-10 carbon atoms; R 2 represents cyano, nitro, formyl, carboxyl, carbamoyl, or an alkoxycarbonyl group having 2-8 carbon atoms; R 3 represents hydroxyl, amino, carboxyl, mercapto, OR 4 or NHR 5 in which each of R 4 and R 5 is an alkyl group having 1-8 carbon atoms which may have a substituent selected from the group consisting of halogen, hydroxyl, nitro, cyano, amino, an aryl group having 6-10 carbon atoms, and an aryloxy group having 6-10 carbon atoms; X represents oxygen, —N(R 6 )—, or —S(O) n — in which R 6 is hydrogen, an alkyl group having 1-8 carbon atoms, or the group for R 1 , and n is an integer of 0 to2; and Y represents sulfur.