Antibacterial 8-cyano-1-cyclopropyl-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids

An 8-cyano-1-cyclopropyl-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid derivative of the formula ##STR26## in which Y represents carboxyl, nitrile, --COOR.sup.1 or --CONR.sup.2 R.sup.3,

• wherein
• R.sup.1 represents alkyl, and
• R.sup.2 and R.sup.3 each independently represent hydrogen or alkyl, and
• R.sup.3 represents an unsubstituted phenyl,
• X.sup.1 represents hydrogen, nitro, alkyl, or halogen,
• X.sup.4 represents hydrogen or halogen or alkyl,
• R.sup.4 and R.sup.5, together with the nitrogen atom to which they are bonded, form 6-membered heterocyclic ring which additionally has the group ##STR27## as a ring member and which is unsubstituted or mono-, di- or trisubstituted on the carbon atoms by identical or different substituents said substituents being C.sub.1 -C.sub.4 -alkyl, phenyl and cyclohexyl and said substituents being unsubstituted or mono-, di-or trisubstituted by chlorine, fluorine, bromine, methyl, phenyl, hydroxyl, methoxy, benzloxy, nitro or piperidino, 2-thienyl, hydroxy, alkoxy with one to three carbon atoms, amino, methylamino, ethylamino, aminomethyl, methylaminomethyl and ethylaminomethyl,
• wherein
• R.sup.6 represents hydrogen, a branched or straight-chain alkyl, alkenyl or alkynyl which has 1 to 6 carbon atoms and is unsubstituted or substituted by one or two hydroxyl, alkoxy, alkylamino or dialkylamino groups with in each case 1 to 3 carbon atoms in the alkyl radical, cyano, alkoxycarbonyl with 1 to 4 carbon atoms in the alcohol part, phenylalkyl which is unsubstituted and has up to 4 carbon atoms in the aliphatic part, phenacyl which is unsubstituted or mono- or disubstituted by hydroxyl, methoxy, chlorine or fluorine, or an oxoalkyl radical with up to 6 carbon atoms, or furthermore denotes a radical COR.sup.7 or SO.sub.2 R.sup.8,
• wherein
• R.sup.7 represents hydrogen, straight-chain or branched alkyl which has 1 to 4 carbon atoms and is unsubstituted or substituted by 1 or 2 substituents said substituents being amino, alkyoxycarbonyl with 1 to 3 carbon atoms in the alkyl part, carbonxyl, alkoxy with 1 to 3 carbon atoms and halogen, or amino, alkylamino or dialkylamino with 1 to 5 carbon atoms in the alkyl part, and
• R.sup.8 represents straight-chain or branched alkyl with 1 to 3 carbon atoms, and pharmaceutically acceptable hydrates or salts thereof, and their esters.