Process for the preparation of novel cycloalkanoquinolone- carboxylic acid esters

Novel cycloalkanoquinolonecarboxylic acid esters of the accompanying formula I, in which R denotes an alkyl group having 1 to 5, preferably 1 to 3, carbon atoms; X denotes an alkyl group having 1 to 5 carbon atoms, which is optionally substituted by halogen, preferably chlorine, or a hydroxy, alkoxy, acyloxy or alkylmercapto group, or denotes an alkenyl group having up to 5 carbon atoms; and n denotes one of the numbers 3 to 5 are prepared; the process is based on the esterification of the corresponding free acid with the agent donating the radical R. The free carboxylic acid can for its part be obtained by cyclisation of the corresponding compounds which carry a corresponding omega -haloalkyl or omega -alkenyl group in the 8-position. The compounds of the formula I can be used for the preparation of medicaments having antimicrobial action.