19457-55-7

50-00-0

63-05-8

19457-55-7

The general procedure for the synthesis of (8R,9S,10R,13S,14S)-10,13-dimethyl-6-methylene-7,8,9,10,11,12,13,14,15,16-decahydro-1H-cyclopenta[a]phenanthrene-3,17(2H,6H)-dione from formaldehyde and androstenedione was as follows: 2.0 g of androst-4-ene-3,17 -dione (0.01 mol) was dissolved in 13 mL of anhydrous THF and 2 mL of ethanol, 2 mL of anhydrous triethyl orthoformate and 26 mg of p-toluenesulfonic acid monohydrate were added. The reaction mixture was stirred at 40 °C for about 1 hour. Subsequently, 50 mg of p-toluenesulfonic acid monohydrate was added and stirring was continued for about 2 hours. After the reaction was completed, cooled to room temperature, 1 mL of N-methylaniline and 1 mL of 40% formaldehyde aqueous solution was added to the reaction flask and the mixture was stirred at 40°C for about 4 hours. After cooling to room temperature again, 10 mL of 37% HCl was added and stirring was continued for 2 hours. The reaction solution was transferred to a partition funnel and extracted with EtOAc. The organic phase was dried with Na2SO4 and purified by silica gel chromatography to afford 0.84 g of 6-methylene-androst-4-ene-3,17-dione (3) as a white solid with >95% chemical purity and a melting point of 159-163 °C.