| 主权项 |
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 mixture mass to between 7 to 8, and h) isolating Zolmitriptan (I) of desired purity. |
