Acetic Anhydride → HCID 14284770, compound

Participants

Reaction Steps

(22E, 24R)-5α-Ergosta-2,22-dien-6-one (S. Takatsuto and N. Ikekawa, Chem. Pharm. Bull., 32, 2001 (1984)) (15.0 g, 37.9 mmol) was dissolved in a solvent mixture of tetrahydrofuran (100 ml) and water (10 ml), added with osmium tetraoxide (500 mg) and N-methyl-morpholine-N-oxide (15 g), and stirred at room temperature for 6 hours. Water (30 ml) and sodium hydrogen sulfite (1 g) were added thereto, and after stirring at room temperature for 30 minutes, extracted with dichloromethane. The obtained organic layer was washed with 2N hydrochloric acid and then with water, and dried over anhydrous magnesium sulfate. A product obtained by removal of solvents with an evaporator was dissolved in pyridine (100 ml), 50 ml of acetic anhydride was added thereto, and stirred at 60° C. overnight. After cooling, 100 ml of water was added thereto and left still for 30 minutes, then extracted with ethyl acetate. The obtained organic layer was washed with 2N hydrochloric acid, with saturated aqueous solution of sodium hydrogencarbonate and with saturated brine, successively, and dried over anhydrous magnesium sulfate, then solvents were removed by an evaporator to give a crude product. It was purified by means of silica-gel column chromatography to give (22E, 24R)-2α,3α-diacetoxy-5α-ergost-22-en-6-one (2.0 g, 12 %):

Provenance & Evidence