反应详情

Langlois et. al. in published PCT Appln. No. WO 01/58868 disclose a further method for preparation of the (S,S) diastereoisomer of N-[(S)-1-carbethoxybutyl]-(S)-alanine, a key intermediate for perindopril comprising reacting benzyl ester of (2S, 3aS,7aS)-2-carboxyperhydroindole, p-toluenesulfonate salt with (S,S) diastereoisomer of N-[(S)-1-carbethoxybutyl]-(S)-alanine in the presence of 0.4 to 0.6 moles of 1-hydroxybenzotriazole; 1 to 1.2 moles of dicyclohexylcarbodiimide and I mole of triethylamine at 77° C. to give the dipeptide compound, which on debenzylation gives perindopril.