VERFAHREN ZUR HERSTELLUNG PHARMAKOLOGISCH VERTRÄGLICHER SALZE VON N-(1(S)-ETHOXYCARBONYL-3- PHENYLPROPYL)-L-ALANYL AMINOSÄUREN

摘要

Preparation of salts of N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanyl amino acid derivatives of formula (R1)NH-CH(R2)-CO2H (I) comprises: (a) condensing an amino acid with N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanine N-carboxyanhydride of formula (II), under basic conditions; (b) decarboxylating the condensate under neutral to acidic conditions to give (I); and (c) and converting (I) to its salt. Steps (a), (b) and optionally (c) are carried out in aqueous liquid to inhibit the formation of by-products of formula (III): -N(R1)CH(R2)-C(O)- = e.g. group of formula (i).