Process and composition for amino-terminal, alpha -aspartyl and alpha -glutamyl dipeptide esters

摘要

Reaction of a ketoxime-derivatized resin with a strong acid salt of aspartic anhydride or glutamic anhydride yields a novel aspartyl or glutamyl ketoxime ester-derivatized resin, wherein the aspartyl or glutamyl groups are esterified predominantly at the alpha -carboxyl group and wherein the aspartyl or glutamyl groups are not covalently protected at the amino group or the carboxyl group that is not esterified. Aminolysis in the presence of a weak acid of the novel aspartyl or glutamyl ketoxime ester-derivatized resin, wherein the aspartyl or glutamyl groups remain as the strong acid salt, with a salt of an amino acid with a base or an amino acid ester yields the corresponding dipeptide or dipeptide ester. After aminoylsis, the ketoxime-derivatized resin can be reused. An advantageous solid-phase method is thus provided for making alpha -L-aspartyl dipeptide ester sweeteners, including aspartame, and the immunopotentiating dipeptide, alpha -L-glutamyl-L-asparagine.