Patent ID: 7342035
Filing Date: 2008-03-11
Classification: C07D

Abstract:
1. Process for preparing a pharmaceutically active compound, zolmitriptan, which comprises: a) Preparation of the diazononium salt from the aniline hydrochloride of formula (II) followed by reduction and acidification to give the hydrazine of formula (III): b) In situ reaction of the hydrazine hydrochloride of formula (III) with α-keto-δ-valerolactone, to give the hydrazone of formula (IV): c) Fischer indole synthesis of the hydrazone of formula (IV), to give the pyranoindolone of formula (V): d) Transesterification of the pyranoindolone of formula (V), to provide the compound of formula (VI): in which R represents a straight or branched C1-C4 alkyl chain; e) Conversion of the hydroxyl group of the compound of formula (VI) into dimethylamino, to give the indolecarboxylate of formula (VII): in which R represents a straight or branched C1-C4 alkyl chain; f) Saponification of the 2-carboalkoxy group of the compound of formula (VII), to give the indolecarboxylic acid of formula (VIII): and g) Decarboxylation of the indolecarboxylic acid of formula (VIII), to give zolmitriptan.