METHOD OF PREPARING .ALPHA.-L-ASPARTYL-L-PHENYLALALINE METHYL ESTER HYDROCHLORIDE

摘要

.alpha.-L-Aspartyl-L-phenylalanine methyl ester hydrochloride is prepared by extracting N-formyl-.alpha.-L-aspartyl-L-phenylalanine methyl ester from a reaction mixture containing same in an organic solvent, with water at a temperature of from 40.degree.C to 80.degree.C, and allowing the resulting mixture to separate into an aqueous layer and an organic layer, the aqueous layer containing the N-formyl-.alpha.-L-aspartyl-L-phenylalanine methyl ester. The aqueous layer is isolated and the N-formyl-a-L-aspartyl-L-phenylalanine methyl ester contained therein is deformylated at a temperature of from 40.degree.C to 80.degree.C. .alpha.-L-Aspartyl-L-phenylalanine methyl ester is thereafter crystallized out in the form of its hydro-chloride salt. The method of the invention does not necessitate the isolation of an intermediate by solid-liquid separation during the course of preparing the .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride.