Quinolone carboxylic acid derivatives and process for preparing the same

Abstract

The present invention relates to quinolone carboxylic acid derivatives having useful antibacterial activities of formula (I): ##STR1## wherein, R.sub.1, R.sub.2, and R.sub.3, which may be the same or different, are each hydrogen or a halogen atom, or a lower alkyl group optionally substituted with an amino or a hydroxy group; R.sub.4 is hydrogen atom, a lower alkyl, benzyl, t-butoxycarbonyl or ethoxycarbonyl group; R.sub.5 is hydrogen, chlorine atom, methyl or an amino group; R.sub.6 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.

Dependencies are inferred from the claim text.