The present invention provides a process for producing an optically active compound having a thio group at the 2-position important for manufacturing medicines. An optically active compound having a hydroxyl group at the 2-position is chlorinated with inversion of the configuration at the 2-position, and the resultant optically active compound having a chlorine atom at the 2-position is reacted with a metal thiolate to introduce a thio group with inversion of the configuration at the 2-position. This process is capable of minimizing racemization and producing an optically active compound having a thio group at the 2-position at low cost in high yield. When the optically active compound having a chlorine atom at the 2-position is reacted with the metal thiolate in coexistence with water in the reaction system, the optically active compound having a thio group at the 2-position with higher optical purity can be produced in higher yield. An optically active carboxylic acid having a thio group at the 2-position is crystallized in the presence of an aliphatic hydrocarbon solvent and/or a sulfur-containing solvent to effectively remove coexistent impurities such as an optical isomer and the like, thereby producing crystals of an optically active carboxylic acid having a thio group at the 2-position with higher purity.
本发明提供了一种生产光学活性化合物的工艺,该化合物的 2 位上有一个
硫代基,这对生产药物非常重要。一种在 2 位上具有羟基的光学活性化合物在 2 位上进行反转构型的
氯化处理,然后将得到的在 2 位上具有
氯原子的光学活性化合物与
硫代
金属进行反应,在 2 位上引入反转构型的
硫代基团。这种工艺能够最大限度地减少消旋化,并以低成本、高产率生产出在 2 位上具有
硫代基团的光学活性化合物。当在 2 位上有一个
氯原子的光学活性化合物与
金属
硫醇酸盐在反应体系中与
水共存的情况下发生反应时,可生产出光学纯度更高的在 2 位上有一个
硫代基团的光学活性化合物。在脂肪烃溶剂和/或含
硫溶剂的存在下结晶 2 位具有
硫代基团的光学活性
羧酸,可有效去除共存的杂质(如光学异构体等),从而生产出纯度更高的 2 位具有
硫代基团的光学活性
羧酸晶体。