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; andX 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.

Abstract: The present invention relates to novel 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; andX is 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.

Abstract: The present invention relates to novel quinoline derivatives of formula (I): ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, X, Y and Z are defined as in the specification, and pharmaceutically acceptable acid addition salts thereof, and also to processes for preparing these compounds.The present invention also provides an antibacterial composition comprising a compound of formula (I) or its acid addition salt as an active ingredient and pharmaceutically acceptable excipient.The novel quinoline derivatives of the present invention have an excellent antibacterial activity against bacteria or bacteroides.