A nitrous acid salt is added at a temperature of 10 to 80°C to an aqueous solution which contains an optically active 2-aminocarboxylic acid (4) and a protonic acid, the amount of the latter acid being 1 to 3 equivalents to the former, and which has a proton concentration of 0.5 to 2 mol/kg to conduct a reaction to thereby produce an optically active 2-hydroxycarboxylic acid (1). Thionyl chloride and a basic compound are caused to act on the compound (1) to chlorinate it and simultaneously invert the configuration in the 2-position. Thus, an optically active 2-chlorocarboxylic acid chloride (5) is induced. The compound (5) is hydrolyzed to induce an optically active 2-chlorocarboxylic acid (2). The compound (2) is reacted with a thioacetic acid salt to incorporate an acetylthio group thereinto and simultaneously invert the configuration in the 2-position to thereby produce an optically active 2-acetylthiocarboxylic acid (3).
在 10 至 80°C 的温度下,向含有光学活性 2-
氨基
羧酸 (4) 和质子酸的
水溶液中加入
亚硝酸盐,后者的量为前者的 1 至 3 个当量,质子浓度为 0.5 至 2 摩尔/千克,以进行反应,从而生成光学活性 2-羟基
羧酸 (1)。亚
硫酰氯和碱性化合物作用于化合物(1),使其
氯化,同时将 2 位的构型反转。这样,一种光学活性的 2-
氯羧酸氯化物(5)就产生了。化合物 (5) 经过
水解后会生成具有光学活性的 2-
氯羧酸 (2)。化合物 (2) 与
硫代乙酸盐反应,在其中加入乙酰
硫基,同时将 2 位的构型反转,从而生成光学活性 2-乙酰
硫代
羧酸 (3)。