METHOD FOR PREPARING SALTS OF ASPARTAME FROM N-PROTECTED ASPARTAME

摘要

Method for preparing a salt of aspartylphenylalanine methyl ester from N-protected aspartylphenylalanine methyl ester involving cleaving off the protective group by treatment with an acid, in the course of which, first of all, N-protected aspartylphenylalanine methyl ester is caused to react in an aqueous medium and in the presence of methanol at a temperature of from 0 to 80° C. with from 0.8 to 2 equivalents of acesulphamic acid for at least such a time that the conversion to the salt of aspartylphenylalanine methyl ester and acesulphamic acid has been completed to an adequate degree, and then the salt formed in the first step is isolated in precipitated form at a temperature of 30° C. or lower.