Preparation process of alpha -L-aspartyl-L-phenylalanine methyl ester or hydrochloride thereof

摘要

The present invention relates to a process for preparing alpha -L-aspartyl-L-phenylalanine methyl ester or its hydrochloride. alpha -L-aspartyl-L-phenylalanine methyl ester or its hydrochloride is prepared by a process comprising: condensating N-formyl-L-aspartic acid anhydride and L-phenylalanine in water or in water containing methanol at a pH in the range of 7-12 to form N-formyl- alpha -L-aspartyl-L-phenylalanine; acidifying the reaction mixture successively with hydrochloric acid in the presence of methanol without isolating the N-formyl- alpha -L-aspartyl-L-phenylalanine so as to bring it into contact with hydrochloric acid in the presence of methanol for reaction and thereby to deposit alpha -L-aspartyl-L-phenylalanine methyl ester hydrochloride; separating the alpha -L-aspartyl-L-phenylalanine methyl ester hydrochloride; and neutralizing said hydrochloride as required.