The synthesis of epalrestat,an aldose reductase inhibitor, was improved. The yield of its intermediate 3-carboxymethyl rhodanine was raised to 76.4%.

对醛搪还原酶抑制剂依帕司他的合成工艺作了改进，使中间体绕丹宁乙酸的收率提高到76．4％。