A compound of formula (II) wherein (a) represents a divalent benzene residue which is unsubstituted or substituted by one or two additional substituents independently selected from lower alkyl, halo-lower alkyl, hydroxy-lower alkyl, lower alkoxy-lower alkyl, acyloxy-lower alkyl, phenyl, hydroxy, lower alkoxy, hydroxy-lower alkoxy, lower alkoxy-lower alkoxy, phenyl-lower alkoxy, lower alkylcarbonyloxy, amino, mono(lower alkyl)amino, di(lower alkyl)amino, mono(lower alkenyl)amino, di(lower alkenyl)amino, lower alkoxycarbonylamino, lower alkylcarbonylamino, substituted amino wherein the two substituents on nitrogen form together with the nitrogen heterocyclyl, lower alkylcarbonyl, carboxy, lower 15 alkoxycarbonyl, cyano, halogen, and nitro； or wherein two adjacent substituents can be methylenedioxy； or a divalent pyridine residue (Z = N) which is unsubstituted or substituted additionally by lower alkyl, lower alkoxy, lower alkoxy-lower alkoxy,amino, optionally substituted by one or two substituents selected from lower alkyl, lower alkenyl and alkylcarbonyl, halo-20 lower alkyl, lower alkoxy-lower alkyl, or halogen； R1 represents hydrogen, lower alkylcarbonyl, hydroxy-lower alkylor cyano-loweralkyl； and R2 represents a group selected from: (b), (c) and (d)； or pharmaceutically acceptable salts thereof.
