PROCESS FOR PREPARING PHARMACOLOGICALLY ACCEPTABLE SALTS OF N-(1(S)-ETHOXYCARBONYL-3-PHENYLPROPYL)-L-ALANYL AMINO ACIDS

摘要

A process for preparing pharmacologically acceptable salts of N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanyl amino acids, comprising the steps of: condensing an amino acid with N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanine N-carboxyanhydride under basic conditions; decarboxylating the condensate under neutral to acidic conditions to prepare an N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanyl amino acid; and converting the product to a pharmacologically acceptable salt thereof, characterized in that a series of procedures up to the formation of a pharmacologically acceptable salt or up to the withdrawal of the pharmaceutically acceptable salt thereof are carried out in an aqueous liquid to inhibit the production of a by-product (3). According to this process, high-quality pharmacologically acceptable salts of N-(1(S)-ethoxycarbonyl-3-phenylpropyl)-L-alanyl amino acids can be prepared in high yields in a cost-effective manner on a commercial scale.