Novel quinolone carboxylic acid derivatives and process for preparing the same.

摘要

The present invention relates to novel quinolone carboxylic acid derivatives of formula (I): <CHEM> wherein, R1, R2 and R3, which may be the same or different, are each hydrogen or a halogen atom, or a lower alkyl group or a lower alkyl group substituted with an amino or hydroxy group; R4 is hydrogen atom, a lower alkyl, benzyl, t-butoxycarbonyl or ethoxycarbonyl group; R5 is hydrogen, chlorine atom, methyl or an amino group; R6 is a lower alkyl group, or a cyclopropyl or a phenyl group optionally substituted with a halogen atom; and X is nitrogen atom, or a methyne group optionally substituted with a lower alkyl or a lower alkoxy group or a halogen atom, and pharmaceutically acceptable salts thereof, and processes for preparing these compounds. The present invention also relates to novel intermediates which are useful for preparing the quinolone compounds of the invention. The novel quinolone carboxylic acid derivatives of the present invention have a broad spectrum of potent antibacterial activities against various microorganisms.