The present invention discloses a process for the synthesis and isolation of (2S, 3aS, 7aS)-1-[(2S)-2-[[(1S)-1-(ethoxycarbonyl)butyl]amino]-1-oxopropyl] octahydro-1H-indole-2-carboxylic acid and its tert-butylamine salt, by condensing (2S, 3aS, 7aS)-octahydroindole-2-carboxylic acid benzyl ester and N[(S)1-carboxybutyl]-(S)-alanine ethyl ester in nonreactive solvents in turn avoiding the formation of impurity viz. N-acetyl (2S,3aS,7aS)-octahydroindole-2-carboxylic acid benzyl ester (Formula V). The de-protection of benzyl ester group is optimized and then isolation of the product from aqueous layer by extraction using an organic solvent, which eliminates the need of lyophilization. The process of the present invention yields perindopril erbumnine salt of Formula 1B free of contaminants derivable from dicyclohexylcarbodiimide and impurities originated by the use of ethyl acetate.
本发明揭示了一种合成和分离(2S, 3aS, 7aS)-1-[(2S)-2-[[(1S)-1-(乙氧羰基)丁基]
氨基]-1-氧代丙基]
辛烷基-1H-
吲哚-2-羧酸及其
叔丁基胺盐的方法,通过在非反应性溶剂中依次将(2S, 3aS, 7aS)-
辛烷基-1H-
吲哚-2-羧酸苄酯和N[(S)1-羧基丁基]-(S)-
丙氨酸乙酯缩合,避免形成杂质,即N-乙酰(2S,3aS,7aS)-
辛烷基-1H-
吲哚-2-羧酸苄酯(式V)。苄酯基的去保护经过优化,然后通过有机溶剂的萃取从
水层中分离产物,从而消除了冷冻干燥的需要。本发明的方法使得得到的
盐酸贝利普利酯盐(Formula 1B)不含有由二环己基碳酰胺和
乙酸乙酯使用产生的杂质。