A compound represented by the general formula (I), or a pharmaceutically acceptable salt thereof. ** Formula wherein R a represents a hydrogen, halogen, hydroxy, or alkoxy atom in which the alkyl moiety is linear or branched and has from 1 to 10 carbon atoms, R1 and R2 may be the same or different, and each represents a hydrogen atom, optionally substituted linear or branched alkyl having from 1 to 10 carbon atoms or cycloalkyl, or R1 and R2 are combine together with the nitrogen atom adjacent thereto to form a nitrogen-containing heterocyclic group, and Z represents a bicyclic heterocyclic group in which two optionally substituted six-membered rings condense with each other, wherein； linear or branched alkyl having 1 to carbon atoms is optionally substituted with 1 to 3 substituents, which may be the same or different, selected from the group consisting of halogen, hydroxy, sulfanyl, nitro, cyano, carboxy, carbamoyl, cycloalkyl C3-8, C6-14 aryl, an aliphatic heterocyclic group, an aromatic heterocyclic group, C1-10 alkoxy, C3-8 cycloalkoxy, C6-14 aryloxy, C7-16 aralkyloxy, C2-11 alkanoyloxy, C7-15 aroyloxy, alkylsulfanyl C1-10, -NRXRY, C2-11 alkanoyl, C7-15 aroyl, C1-10 alkoxycarbonyl, C6-14 aryloxycarbonyl, C1-10 alkylcarbamoyl or C1-10 dialkylcarbamoyl, in which the two C1-10 alkyl radicals of dialkylcarbamoyl C1 -10 may be the same or different； Z is optionally substituted with 1 to 3 substituents, which may be the same or different, selected from the group consisting of oxo, halogen, hydroxyl, sulfanyl, nitro, cyano, carboxy, carbamoyl, C1-10 alkyl, C3-8 cycloalkyl, aryl C6-14, an aliphatic heterocyclic group, an aromatic heterocyclic group, C1-10 alkoxy, C3-8 cycloalkoxy, C6-14 aryloxy, C7-16 aralkyloxy, C2-11 alkanoyloxy, C7-15 aroyloxy, C1-10 alkylsulfanyl, - NRXbRYb, C2-11 alkanoyl, C7-15 aroyl, C1-10 alkoxycarbonyl, C6-14 aryloxycarbonyl, C1-10 alkylcarbamoyl, or C1-10 dialkylcarbamoyl； RX, RY, RXb and RYb may be the same or different, and are selected fro
