Patent ID: 8901141

Claim:
A compound represented by the following formula (I″): wherein R 1 is (1) mono- or di-C 1-6 alkylamino, or (2) a C 1-9 alkyl optionally substituted by a substituent selected from the group consisting of halogen, hydroxy, C 3-6 cycloalkyl, an optionally substituted C 1-6 alkoxy, C 1-6 alkyl-carbonyloxy, C 3-6 cycloalkyl-carbonyloxy and an optionally substituted C 3-6 cycloalkyloxy; R 2 is an optionally substituted phenyl, an optionally substituted pyridyl or an optionally substituted pyrimidinyl; and Rb is hydrogen, halogen, cyano, an optionally substituted C 1-9 alkyl, an optionally substituted C 1-6 alkoxy, or C 3-6 cycloalkyl, or a salt thereof.