METHOD FOR THE PREPARATION OF HIGH PURITY ALMOTRIPTAN

摘要

A method for the preparation and purification of the substance of formula (I), i.e. 3-[2- (dimethylamino)ethyl]-5-(1-pyrrolidinylsulfonylmethyl)-1H-indole, which comprises (a) conversion of 4-(1-pyrrolidinylsulfonylmethyl)phenylhydrazine of formula (III) by reaction with an organic or inorganic acid to a salt that is insoluble or poorly soluble in water, which is converted to 3-(2-aminoethyl)-5-(1-pyrrolidinylsulfonylmethyl)indole of formula (VII), which is further converted without isolation to a solution of the almotriptan base, which provides a crystalline salt of almotriptan with an organic or inorganic acid; (b) conversion of the salt of almotriptan to the almotriptan base, which separates from the solution in the crystalline form; (c) purification of the almotriptan base by crystallization from an organic solvent.