| abstract |
A compound of the formula: wherein -X3=X2-X1=N- is a group of the formula: R1 is hydrogen or halogen, R2 is halogen, R3 is hydrogen, nitro, amino optionally having at least one substituent or a heterocyclic group optionally having at least one substituent, R4 and R5 are each hydrogen, or halogen, R6 and R8 are each hydrogen, halogen, lower alkyl, hydroxy, lower alkylthio, amino optionally substituted with lower alkyl, or lower alkoxy optionally substituted with a substituent selected from the group consisting of hydroxy, lower alkoxy, amino, lower alkylamino and aryl optionally substituted with lower alkoxy, R7 is hydrogen or lower alkyl, A is lower alkylene, and Q is O or N-R9 is hydrogen or acyl, provided that R3 is not hydrogen when X1 is C-R6, in which R6 is hydrogen, and pharmaceutically acceptable salts thereof. |