METHOD OF SYNTHESIS OF PIPERIDINYLAMINOMETHYL-TRIFLUOROMETHYL CYCLIC ESTERS Russian patent published in 2002 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: invention relates to a novel method of synthesis of a diastereomeric mixture of piperidinylaminomethyl-trifluoromethyl cyclic esters of the formulas (Ia) and (Ib) and their pharmaceutically acceptable salts where R¹ is C₁-C₆-alkyl; R² is C₁-C₆-alkyl, halogen-C₁-C₆-alkyl or phenyl or substituted phenyl; R³ is a hydrogen or halogen atom; m = 0, 1 or 2 where indicated mixture is high-enriched with the compound of the formula (Ia). Invention describes a method that involves interaction of a mixture of compounds (Ia) and (Ib) with the acid of the formula HX that is taken among the group consisting of (S)-(+)-mandelic acid, D-(-)-tartaric acid, di-p-toluoyl-(D)-tartaric acid and other acids, crystallization of HX salt of a diastereomeric mixture of products from its solution, treatment of the formed mixture of compounds with a base to yield a mixture of compounds (Ia) and (Ib) enriched with the compound of the formula (Ia). The use of defined acids indicated above for separation of a diastereomeric mixture ensures to obtain the high degree of diastereomeric purity (above 95%). Invention relates to also a mixture of compounds (Ia) and (Ib) and intermediate compounds used for synthesis of compounds of the formulas (Ia) and (Ib). EFFECT: improved method of synthesis. 22 cl