A convenient synthesis of optically pure (2R, 3R)-2, 3- Epoxysuccinyl - dipeptides
作者:Andreas Korn、Sabine Rudolph-Böhner、Luis Moroder
DOI:10.1016/s0040-4020(01)85561-7
日期:1994.1
(2R,3R)-trans-Epoxysuccinyl-dipeptides (7a-7d) were synthesized by acylation of dipeptides with the N-hydroxysuccinimide or pentafluorophenyl ester of monoethyl (2R,3R)-trans-epoxysuccinate (6a,6b). A nucleophilic oxirane ring opening by N-hydroxysuccinimide and pentafluorophenol during the preparation of the active esters could not be observed. Subsequent saponification of the monoethyl ester 7a-7d with KOH in ethanolic solution allowed to produce the dipeptide derivatives as potassium salts (8a,8d) which were found to be stable on storage in the cold. The attempts to convert (2R,3R)-trans-epoxysuccinyl-glycyl-proline (7a) into the corresponding (2S,3S)-trans-epithiosuccinyl derivative via an oxygen sulfur exchange reaction with 3-methylbenzothiazole-2-thione failed completely as among the various products of unknown nature formed only the desulfurated fumaryl derivative could be isolated and characterized.
(2R,3R)-反式-环氧丁二酰二肽(7a-7d)是通过使用单乙基(2R,3R)-反式-环氧丁二酸酯(6a,6b)的N-羟基丁二酰亚胺或五氟苯酯对二肽进行酰化反应合成的。在制备活性酯的过程中,无法观察到由N-羟基丁二酰亚胺和五氟苯酚引发的环氧乙烷环的亲核开环反应。随后,将单乙酯7a-7d与乙醇溶液中的氢氧化钾进行皂化反应,生成了作为钾盐的二肽衍生物(8a,8d),这些衍生物在冷处保存时表现出稳定性。尝试通过与3-甲基苯并噻唑-2-硫酮进行氧硫交换反应将(2R,3R)-反式-环氧丁二酰甘氨酰脯氨酸(7a)转化为相应的(2S,3S)-反式-环氧丁二硫酰衍生物,但这一尝试完全失败。在生成的各种未知性质产物中,唯一能分离并表征的是脱硫的富马酰衍生物。