Method for preparing alpha-L-aspartyl-L-phenylalanine.

摘要

This invention is directed to provide a method for obtaining alpha -L-aspartyl-L-phenylalanine selectively in high yields. Diffusion dialysis with an ion exchange membrane is used to decrease hydrochloric acid concentration of a mixed solution containing hydrochloric acid and one or more of four alpha -L-aspartyl-L-phenylalanine derivatives, i.e., alpha -L-aspartyl-L-phenylalanine methyl ester, alpha -L-aspartyl-L-phenylalanine, alpha -L-aspartyl-L-phenylalanine- beta -methyl ester and alpha -L-aspartyl-L-phenylalanine dimethyl ester. The resultant solution is concentrated, to which a base is added for neutralization. Subsequently, alpha -L-aspartyl-L-phenylalanine is crystallized and isolated.