METHOD FOR PREPARING SALTS OF ASPARTAME FROM N-PROTECTED ASPARTAME

摘要

: Method for preparing a salt of aspartylphenyl-alanine methyl ester from N-protected aspartylphenylalanine methyl ester involving cleaving off the protective group by treatment with an acid, characterized in that, in a first step, 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 in a second step the salt formed in the first step is obtained in precipitated form at a temperature of 30°C or lower. 2. Method according to Claim 1, characterized in that N-protected aspartylphenylalanine methyl ester is reacted in the presence of a mineral acid selected from the group consisting of hydrochloric acid, sulphuric acid or phosphoric acid, in an amount of at most 0.5 molar equivalents with respect to the acesulphamic acid No. of Pages : 15 No. of Claims : 9