Method of preparing alpha -L-aspartyl-L-phenylalanine methyl ester and its hydrochloride

摘要

A method for preparing alpha -L-aspartyl-L-phenylalanine methyl ester and its hydrochloride which comprises dissolving alpha -L-aspartyl-L-phenylalanine dimethyl ester in a mixture of 0-10% (v/v) methanol, 8-55% (v/v) of concentrated hydrochloric acid, and water (remainder) to a concentration of 0.01 mol/dl to 0.30 mol/dl; holding the resulting solution at one or more temperatures between 0 DEG and 60 DEG C. for a time sufficient for crystals of alpha -L-aspartyl-L-phenylalanine methyl ester hydrochloride to precipitate out, and isolating the crystals. The hydrochloride may then be treated with alkali to yield alpha -L-aspartyl-L-phenylalanine methyl ester.