Boron trifluoride etherate → HCID 54368796, compound

Participants

Reaction Conditions

Reaction Steps

Under an argon atmosphere at less than -30° C. boron trifluoride etherate (100 ml., 115.4 g., 0.704 mole) was added to a solution of triethylorthoformate (109.5 ml., 97.56 g., 0.658 mole) in dichloromethane (300 ml.). The temperature was raised to 0° C., kept there for 15 min., then lowered to -70° C. A solution of (5α,17β)-17-[(tetrahydro-2H-pyran-2-yl)oxy]androstan-3-one (0.3 mole) in dichloromethane (250 ml.+50 ml. for rinsing) was then added, followed by diisopropylethylamine (166.5 ml., 123.5 g., 0.955 mole), the latter while maintaining the temperature at less then -55° C. The temperature was lowered to -70° C. for 1 hr. The mixture was then quenched in aqueous sodium bicarbonate solution (3 1., made by dissolving 300 g. of sodium bicarbonate in 3.5 1. of water). The layers were separated. The aqueous layer was extracted with dichloromethane (250 ml.). The combined dichloromethane layers were washed twice with cold hydrochloric acid (2N, 1200 ml., 600 ml.), then with half-saturated aqueous sodium bicarbonate solution (800 ml.), dried and stripped of dichloromethane. The residue was triturated with hexane, affording (2α,5α,17β)-2-(diethoxymethyl)-17-[(tetrahydro-2H-pyran-2-yl)oxy]androstan-3-one (70.57 g., 49% yield, m.r. 165°-168° C.).

Provenance & Evidence