Patent ID: 9006453
Filing Date: 2015-04-14
Classification: C07D

Abstract:
1. An improved process for the preparation of Zolmitriptan (I), comprising a) reacting an aqueous solution of diazotized (S)-4-(4-aminobenzyl)-1,3-oxazolidin-2-one with stannous chloride in hydrochloric acid at −15 to 10° C., b) adjusting pH of the reaction mass to between 2 to 6 after completion of reaction, c) filtering the reaction mass, d) readjusting the pH of the filtrate between 6 to 10 to obtain (S)-4-(4-hydrazinobenzyl)-1,3-oxazolidin-2-one of formula (III), e) converting (S)-4-(4-hydrazinobenzyl)-1,3-oxazolidin-2-one of formula (III) to (S)-4-(4-hydrazinobenzyl)-1,3-oxazolidin-2-one hydrochloride of formula (IIIa) by treatment with hydrochloric acid in an organic solvent, f) treating (S)-4-(4-hydrazinobenzyl)-1,3-oxazolidin-2-one hydrochloride of formula (IIIa) with N,N dimethylaminobutyraldehyde diethyl acetal (IV) in aqueous medium at ambient to reflux temperature, g) adjusting the pH of the second reaction mass to between 7 to 8, and h) isolating Zolmitriptan (I).