| abstract |
A method for preparing an α-L-aspartyl-L-phenylalanine alkyl ester, which method comprises: reacting a divalent alkali salt of aspartic acid, having an amino-protective group, with an organic halo ester compound, to form a monovalent, alkali-salt, mixed,anhydride aspartate compound; and condensing the mixed,anhydride aspartate compound with an alkyl ester of L-phenylalanine under alkaline conditions and reducing the pH to an acidic condition after condensation to free the amino and carboxyl groups, to form a mixture consisting essentially of the alpha and beta alkyl ester of α-L-aspartyl-L-phenylalanine. |