Patent ID: 7531656
Filing Date: 2009-05-12
Classification: A61P,C07D

Abstract:
1. A method for making Gatifloxacin containing not more than about 0.1 area- % impurities comprising the steps of: (a) heating a reaction mixture comprising 2-methylpiperazine and 1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-methoxy-4-oxo-3-quinoline carboxylic acid in a dipolar aprotic solvent to a reaction temperature from about 40°C. to about 70°C. for a reaction time in an atmosphere of inert gas; (b) maintaining the reaction mixture at a holding temperature of about 40° C. or less for a holding time, to form a slurry, wherein the holding time is sufficiently long so that there is no further increase in the percent suspended solids for a period of about one-half hour; (c) isolating gatifloxacin from the slurry formed in step (b); (d) slurrying the isolated gatifloxacin with water or a mixture of water and acetonitrile to form a water slurry; and (e) isolating gatifloxacin having about 0.07 area- % or less desmethyl gatifloxacin and about 0.06 area- % or less 2′-methyl gatifloxacin from the water slurry.