NEW PROCESS FOR THE PREPARATION OF (2S,3AS,7AS)-1-[(S)-ALANILE]OCTAHYDRO-1H-INDOLE-2-CARBOXY ACID DERIVATIVES AND THEIR USE FOR SYNTHESING PERINDOPRIL

Process for industrial synthesis of (2S, 3aS, 7aS)-1-(S) alanyl octahydro-2-carboxylic acid derivatives (I) by reaction of alanine derivative (VI) and ester derivative (V) and catalytic hydrogenation. Process for industrial synthesis of (2S, 3aS, 7aS)-1-(S) alanyl octahydro-2-carboxylic acid derivatives of formula (I) comprises reaction of an ester of formula (V) with an alanine of formula (VI) in an organic solvent optionally in the presence of less than 0.6 mole per mole (V) of 1-hydroxybenzotriazole and in the presence of 1-1.2 mole of dicyclohexylcarbodiimide and 1-1.2 mole of triethylamine per mole of (V) at 20-50 degrees C to give a compound of formula (VII) which is then hydrogenated at 1-40 bars and 30-70 degrees C in the presence of a catalyst, preferably rhodium on charcoal or platinum dioxide, to form (I). R1 = H , 1-6C alkyl, or benzyl; and R2 = amino protecting group. An Independent claim is also included for a process for the synthesis of perindopril starting from (I).