METHOD OF PREPARING PREGNANES Russian patent published in 2000 - IPC

FIELD: organic synthesis. SUBSTANCE: described is synthesis of steroid drugs made of sterols of vegetable and animal origin. Method comprises subjecting 17 alpha-OH groups to protection and 17 CN groups to alkylation with cyanated derivatives of ketosteroids followed by hydrolysis, 17-ketosteroids inolude 3.17-diketoandrostanes of formula: wherein R¹ is -α or β-OH- or H; R² is H or OH or together R¹ and R², is double bond; R³ is H or CH₃; R⁴ is H or OH. Prior to alkylation, 3-keto group is protected with unsubstituted or 2-substituted or 2,2-disubstituted propylene ketal. In order to protect 17α-OH, protective group includes alkylvinyl ether. Method makes it possible to increase yield of the main product. EFFECT: more efficient preparation method. 2 cl, 1 diagram, 5 ex