Process for the preparation of the boron difluoride chelate of quinolone-3-carboxylic acid

摘要

A process for the preparation of the boron difluoride chelate of 1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolone carboxylic acid via: (a) the reaction of 1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinolone carboxylic acid ethyl ester with, (b) fluoroboric acid in the presence of poly(methylhydrosiloxane) or hexamethyldisiloxane.