Dimethyl Sulfoxide → Gatifloxacin

Participants

Reaction Conditions

Reaction Steps

A 100 L reactor was charged with DMSO (120 L) and 2-methylpiperazine (8.6 Kg) at 55° C. under nitrogen atmosphere. 1-cyclopropyl-6,7-difluoro-1,4 dihydro-8-methoxy-4-oxo-3-quinoline carboxylic acid (12 kg, divided in 4 portions of 3 kg each) of were added every 2 hours. After completion of the reaction (about 24 hours, monitoring by HPLC), the reaction mixture was cooled to about 47-50° C. and 24 L of water were added at this temperature. The resulting reaction mixture was cooled to 5° C. over 2 hours and maintained at this holding temperature for a holding time 18 hours. The resulting precipitate was collected by filtration to obtain 15.9 Kg of wet Gatifloxacin (11.6 Kg dry, 76% yield).

Provenance & Evidence