Method for synthesis of perindopril and its pharmaceutically acceptable salts

Process for the industrial synthesis of perindopril of formula (I)

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• and pharmaceutically acceptable salts thereof, characterised in that the benzyl ester of formula (IV):
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• wherein Bn represents the benzyl group,
• is reacted with the compound of formula (V):
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• in ethyl acetate,
• in the presence of an amount of from 0.4 to 0.6 mol of 1-hydroxybenzotriazole per mol of compound of formula (IV) employed and in the presence of an amount of from 1 to 1.2 mol of dicyclohexylcarbodiimide per mol of compound of formula (IV) employed, in the absence of triethylamine or in the presence of an amount of triethylamine that is less than or equal to 1 mol per mol of compound of formula (IV) employed, at a temperature of from 20 to 77° C.,
• to yield, after isolation, the compound of formula (VI):
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• wherein Bn represents the benzyl group,
• the carboxylic group of the heterocycle of which is deprotected by catalytic hydrogenation to yield perindopril of formula (I),
• which is converted, if desired, into a pharmaceutically acceptable salt.