METHOD FOR PREPARING PHARMACEUTICAL SUBSTANCE BASED ON PIRIBEDIL Russian patent published in 2020 - IPC C07D405/12 C07D405/14 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing piribedil, which consists in following steps: at first step, 3,4-methylenedioxybenzyl chloride is obtained by chlorination of 1,3-benzodioxole in the presence of paraformaldehyde and hydrochloric acid, wherein 3,4-methylenedioxy benzyl chloride solution is dehydrated using sodium sulphate, at a second step, synthesis of N-(3,4-methylenedioxybenzyl)piperazine from piperazine and 3,4-methylenedioxybenzyl chloride, dissolved in toluene, wherein reaction is carried out at temperature of not higher than 70 °C, at third step, tetraethyl acetal of malondialdehyde from triethyl orthoformate and vinyl acetate in presence of iron chloride, reaction is carried out by maintaining temperature of the reaction mass of 140–145 °C and holding at this temperature for 2–3 hours, at the fourth stage, obtaining 2-oxypyrimidine hydrochloride from tetraethyl acetal of malondialdehyde, urea and hydrochloric acid, crystallisation of 2-oxypyrimidine is carried out at temperature of 3–5 °C for 20–24 hours, at the fifth step, 2-chlorpyrimidine is obtained from 2-oxypyrimidine hydrochloride, phosphorus chloride and phosphorus oxychloride, reaction is carried out at temperature of 100–105 °C for 1–1.5 hours, at the sixth stage, synthesis of piribedil from N-(3,4-methylenedioxybenzyl)piperazine and 2-chloropyrimidine is carried out in the presence of sodium hydroxide followed by purification, recrystallisation of piribedil from isopropyl alcohol, filtration and drying.

EFFECT: technical result is a new method of producing high-purity piribedil with high output of the product.

1 cl, 2 ex