Patent ID: 6423864
Filing Date: 2002-07-23
Classification: C07K

Abstract:
A process of purifying N-[N-(3,3-dimethylbutyl)-L-&agr;-aspartyl]-L-phenylalanine 1-methyl ester by crystallization comprising the steps of:(a) distilling organic solvent from an N-[N-(3,3-dimethylbutyl)-L-&agr;-aspartyl]-L-phenylalanine 1-methyl ester reaction mixture; (b) adding water to the reaction mixture to reach a solvent concentration of between 15% to 35% by weight; (c) holding the reaction mixture for a time of 2 to 20 hours at between 40Â° C. to 45Â° C.; (d) seeding the reaction mixture at a temperature between 30Â° C. to 5Â° C. with an amount of N-[N-(3,3-dimethylbutyl)-L-&agr;-aspartyl]-L-phenylalanine 1 -methyl ester from 0.0001% to 10% by weight based on the amount of N-[N-(3,3-dimethylbutyl)-L-&agr;-aspartyl]-L-phenylalanine 1-methyl ester in the reaction mixture; and (e) cooling the reaction mixture to a temperature of about 4Â° C. over 0.5 hours to 12 hours in order to crystallize N-[N-(3,3-dimethylbutyl)-L-&agr;-aspartyl]-L-phenylalanine 1-methyl ester.