Patent ID: 7323575

Claim:
A process for the synthesis of perindopril or pharmaceutically acceptable salts thereof, starting from a compound of formula (I): wherein the compound of formula (I) is obtained via reaction of racemic indoline-2-caroboxylic acid of formula (III): with a chiral amine to yield a salt of formula (IV): which is filtered off, to yield: the (2S) isomer of formula (IVa): in the form of crystals, which compound of formula (IVa) is treated with hydrochloric acid to yield the compound of formula (I), and after evaporation of the filtrate, a mixture of the (2S) isomer of formula (IVa) and the (2R) isomer of formula (IVb) in which the (2R) isomer predominates: which mixture is treated with hydrochloric acid to yield a mixture of (2R)-indoline-2-carboxylic acid and (2S)-indoline-2-carboxylic acid in which the (2R) acid predominates, the mixture is racemized by reaction with a sodium hydroxide solution, at a temperature of from 140 to 200° C., under a pressure of from 5 to 15 bars, to yield, after isolation, the compound of formula (III), which is then re-subjected to the series of operations described above, after having carried out between 2 and 6 cycles of the above-described series of operations, all the portions made up of the compound of formula (I) are combined, which compound of formula (I) is subjected to catalytic hydrogenation followed by a coupling reaction with a compound of formula (IV): to yield perindopril, wherein the perindopril is converted, if desired, to a pharmaceutically acceptable salt.