摘要:
A method is disclosed for the production of .alpha.-APM.HCl by treating an F-.alpha.-AP derivative with a mixed solvent of methanol, hydrochloric acid and water, wherein the solubility of .alpha.-APM.HCl is lowered to increase the separation yield thereof.
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.