PROCESS FOR PREPARING PRADOFLOXACIN

摘要

PROBLEM TO BE SOLVED: To provide an improved process for preparing pradofloxacin represented by the formula (I).SOLUTION: The substituent in the 7 position is introduced by nucleophilic substitution in an N-methylpyrrolidone-ethanol solvent mixture. Specifically, the process comprises reacting 7-chloro-8-cyano-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid with (1S,6S)-2,8-diazabicyclo-[4.3.0]nonane in a solvent mixture of N-methylpyrrolidone and ethanol, where the solvent mixture contains 70-90 wt.% of ethanol.SELECTED DRAWING: None