7-Amino-1-cyclopropyl-6,8-difluoro-1,4-dihydro-4-oxo-quinoline-3-carboxylic acids and antibacterial agents containing these compounds

Claim 1

A 7-amino-1-cyclopropyl-6,8-difluoro-1,4-dihydro-4-oxo-quinolinecarboxylic acid of the formula (I) ##STR33## in which R 1 and R 2 are identical or different and represent a C 1 -C 4 -alkyl radical which is optionally substituted by a hydroxyl, amino, methylamino or dimethylamino group, and R 1 and R 2 , together with the nitrogen atom to which they are bonded, furthermore form a 5-membered or 6-membered heterocyclic ring, which can additionally have, as a ring member, the atoms or groups --O--, --S--, --SO--, --SO 2 -- or >N-R 3 and which is optionally monosubstituted, disubstituted or trisubstituted at the carbon atoms by C 1 -C 4 -alkyl, hydroxyl, alkoxy having 1-3 carbon atoms, amino, methylamino or ethylamino, and each carbon atom carries no more than one substituent, and R 3 represents hydrogen, a branched or straight-chain alkyl, alkenyl or alkinyl group which has 1 to 6 carbon atoms and is optionally substituted by a hydroxyl, trifluoromethylmercapto, alkoxy, alkylmercapto, alkylamino or dialkylamino group having 1 to 3 carbon atoms per alkyl radical, the cyano group or the alkoxycarbonyl group having 1 to 4 carbon atoms in the alcohol part, or represents the benzyloxycarbonyl group, a phenylalkyl group which has up to 4 carbon atoms in the aliphatic part and is optionally substituted in the phenyl radical by nitro or amino, a phenyl radical which is optionally monosubstituted or disubstituted by hydroxyl, methoxy, chlorine or fluorine, a phenylacyl radical which is optionally monosubstituted or disubstituted by hydroxyl, methoxy, chlorine and fluorine, an oxoalkyl radical having up to 6 carbon atoms and a cycloalkyl-alkyl radical having up to 6 carbon atoms in the cyclic part and up to 3 carbon atoms in the acyclic part, and furthermore denotes a radical COR 4 , CN or SO 2 R 5 , wherein R 4 represents hydrogen or straight-chain or branched alkyl which has 1 to 4 C atoms and is optionally substituted by 1 or 2 substituents selected from amino, alkoxycarbonyl having 1 to 3 carbon atoms in the alkyl part, carboxyl, alkoxy having 1 to 3 carbon atoms and trifluoromethylthio, or represents phenyl which is optionally substituted by chlorine, hydroxyl, amino or carboxyl, or represents alkoxy having 1 to 4 C atoms, alkylthio having 1 or 2 C atoms, benzyloxy or amino, or represents alkylamino which has 1 to 5 C atoms and is optionally substituted by alkoxycarbonyl having 1 to 3 C atoms in the alkyl part or carboxyl, and R 5 represents straight-chain or branched alkyl having 1 to 3 C atoms, phenyl or methylphenyl, and its pharmaceutically useful salts.