METHOD OF PREPARATION OF 17α-ACETOXY-3β-BUTANOYLOXY-6-METHYL-PREGNA-4,6-DIEN-20-ONE FROM MEGESTROL ACETATE Russian patent published in 2018 - IPC C07J7/00 C07J75/00 

FIELD: chemistry.

SUBSTANCE: invention relates to a process for the preparation of 17α-acetoxy-3β-butanoyloxy-6-methyl-pregna-4,6-dien-20-one, comprising the step of reducing the megestrol acetate with sodium borohydride followed by the step of acylation of the resulting precipitate with oil anhydride, decomposition of excess oil anhydride, isolation of the desired product by precipitation and drying of the precipitate, in which the step of reducing the megestrol acetate with sodium borohydride is carried out in a 87 % aqueous solution of isopropanol in the presence of hydrochloric acid at a temperature of (11±2) °C, and the step of acylating the resulting precipitate with an oil anhydride is carried out in acetone in the presence of a catalytic amount of tertiary amine, and the precipitation of the desired product is carried out by a threefold amount with respect to acetone of a mixture of isopropanol, water and hydrochloric acid at a temperature of 13±2 °C, isopropanol and water are used in 2:1 volume ratios, and hydrochloric acid is taken in the molar ratio to the total amount of tertiary amines.

EFFECT: method makes it possible to obtain the desired product with a purity of at least 98 % and a yield of at least 93 % (based on megestrol acetate) without further purification, in a simple and safe manner.

1 cl, 1 ex