Process for preparing extremely pure perindopril and intermediates usable during synthesis

摘要

The invention relates to 1-ä2(S)-Ä1(S)-(ethoxycarbonyl)butylaminoÜpropionylü-(3aS,7aS)octahydro indol-2(S)-carboxylic acid of the Formula I and the t-butylamine salt of the Formula I' thereof free of contaminations derivable from dicyclohexyl carbodiimide, and a process for the preparation thereof. The invention also relates to new intermediates of the general Formula III (wherein R stands for lower alkyl or aryl lower alkyl). The compound of the Formula I - perindopril - is a known ACE inhibitor.