METHOD OF PREPARING ALPHA-L-ASPARTYL-L-PHENYLALANINE METHYL ESTER AND ITS HYDROCHLORIDE

摘要

alpha -L-aspartyl-L-phenylalanine methyl ester and its hydrochloride are prepared by a process which comprises dissolving alpha -L-aspartyl-L-phenylalanine dimethyl ester in a methanol/hydrochloric acid mixture solvent which contains, when hydrochloric acid es expressed in terms of concentrated hydrochloric acid and water, 0 to 10% by volume of methanol, 8 to 55% by volume of concentrated hydrochloric acid and water (balance) to give a solution in which the concentration of said ester is from 0.01 mol/dl to 0.3 mol/dl; holding said solution at 0 to 60 DEG C to crystallize out the formed alpha -L-aspartyl-L-phenylalanine methyl ester as its hydrochloride; isolating said hydrochloride; and obtaining, when required, the free ester by neutralization with an alkali. The ester prepared by this process is useful as a sweetener.