N-(Benzofuranyl-alkoxycarbonyl)-tryptophan ester preparation, for use as tachykinin receptor antagonist intermediate, by reacting hydroxyalkyl-benzofuran with disuccinimidyl carbonate, then with tryptophan ester

摘要

Preparation of (R)-N-(benzo(b)furan-2-ylalkoxycarbonyl)-tryptophan alkyl esters (I) involves: (i) reacting a 2-(hydroxyalkyl)-benzofuran derivative (V) with N,N'-disuccinimidyl carbonate (DSC); and (ii) reacting the obtained 2-(succinimidyloxycarbonyloxy-alkyl)-benzofuran derivative (IV) with an (R)-tryptophan alkyl ester (III). Preparation of (R)-N-(benzofuranylalkoxycarbonyl)-tryptophan alkyl esters of formula (I) involves: (i) reacting a benzofuran derivative of formula (V) with N,N'-succinimidyl carbonate (DSC) in a solvent; and (ii) reacting the obtained 2-(succinimidyloxycarbonyloxy-alkyl)-benzofuran of formula (IV) with an (R)-tryptophan alkyl ester of formula (III). X, Y' = 1-10C alkyl; and Z' = 1-10C alkylene. The definitions of X, Y' and Z' are taken from the disclosure, since these substituents are undefined in the claims.