IMPROVED METHOD FOR PREPARING ALPHA-POLYMORPHOUS ELETRIPTANE BROMOHYDRATE

FIELD: chemical technology. ^ SUBSTANCE: invention relates to a method for synthesis of alpha-polymorphous eletriptane bromohydrate that involves the following steps: (a) treatment of eletriptane solution in 2-butanone with hydrobromic acid and (b) distillation of azeotropic mixture 2-butanone/water up to termination of formation of anhydrous alpha-polymorphous eletriptane bromohydrate. Also, invention relates to a method for preparing crystalline alpha-polymorphous form of eletriptane bromohydrate involving the following steps: (a) treatment of the parent eletriptane bromohydrate substance solution in mixture of 2-butanone and water, and (b) distillation of azeotropic mixture 2-butanone/water up to termination of formation of anhydrous alpha-polymorphous eletriptane bromohydrate. Product synthesized by claimed methods represents exclusively anhydrous eletriptane bromohydrate and prepared with the high yield, i. e. formation of other polymorphous forms or eletriptane bromohydrate solvates in realization of claimed methods do not occur. Invention provides decreasing working ability of the method in synthesis of alpha-polymorphous eletriptane bromohydrate provides high yield of alpha-polymorphous eletriptane bromohydrate. ^ EFFECT: improved method of synthesis. ^ 11 cl, 9 ex