Patent ID: 6897315

Claim:
Process for preparing 3-quinolonecarboxylic acid derivatives of the general formula wherein R′ and R″ together with the linking nitrogen atom form a mono- or bicyclic heterocycle which may optionally contain in all ring moieties further nitrogen, oxygen or sulphur heteroatoms and which may optionally be substituted, wherein R 1 represents C 1 -C 3 -alkyl, FCH 2 —CH 2 —, cyclopropyl, or represents phenyl or cyclopropyl, each of which is optionally mono- to trisubstituted by halogen, R 2 represents C 1 -C 3 -alkyl or benzyl, R 3 represents H, halogen, NH 2 , CH 3 , comprising reacting 8-halogeno-3-quinolonecarboxylic acid derivatives of the general formula wherein Hal represents fluorine or chlorine and R 1 , R 2 , R 3 and are each as defined above, in an aliphatic or cycloaliphatic ether having 4 to 6 carbon atoms as solvent in the presence of C 1 -C 3 -alkanols or benzyl alcohol with wherein M represents sodium or potassium.