Process for the synthesis of R(+)α-lipoic acid comprising the following stages: a) Salifying of racemic 6,8-halo-octanoic acid with S(−)α-methylbenzylamine; b) separation by filtration of the crystallized diastereoisomeric salt of R(+)6,8-di-halo-octanoic acid-S(−)α-methylbenzylamine; c) purification by re-crystallization of the diastereoisomeric salt of R(+)6,8-di-halo-octanoic acid-S(−)α-methylbenzylamine; (d) separation of the diastereoisomeric salt to obtain R(+)6,8-di-halo-octanoic acid by reation of said salt with strong mineral acids in an aqueous solution with a dilution between 2 and 10% by weight; e) esterification of R(+)6,8-di-halo-octanoic acid to obtain the corresponding alkyl ester; f) reaction of the alkyl ester of R(+)6,8-di-halo-octanoic acid in an organic solvent with an aqueous solution of alkali disulfide in presence of a compound for phase transfer catalysis; g) hydolysis of the ester of R(+)α-lipoic acid.
                            合成R(+)
α-硫辛酸的过程包括以下步骤:a)用S(-)α-甲基
苄胺盐酸盐化外消旋6,8-卤代
辛酸;b)通过过滤分离结晶的R(+)6,8-二卤代
辛酸-S(-)α-甲基
苄胺的对映异构体盐酸盐;c)通过再结晶纯化R(+)6,8-二卤代
辛酸-S(-)α-甲基
苄胺的对映异构体盐酸盐;d)用强矿酸在2%至10%重量的
水溶液中反应该盐酸盐分离对映异构体盐酸盐以获得R(+)6,8-二卤代
辛酸;e)酯化R(+)6,8-二卤代
辛酸以获得相应的烷基酯;f)在有机溶剂中与碱性二
硫化物水溶液和相转移催化剂存在下反应R(+)6,8-二卤代
辛酸的烷基酯;g)
水解R(+)
α-硫辛酸的酯。