Hydrochloric Acid → 3beta-Acetoxy-5alpha-pregnan-20-one

참여 물질

반응 단계

To a stirred suspension of 5α-pregnan-3β-ol-20-one (110) (200 g; 0.628 mol) in pyridine (1750 mL) was added acetic anhydride (593 mL; 6.28 mol). Solid was dissolved after 2 hours and the reaction was left for overnight at room temperature. The reaction mixture was diluted with diethyl ether (5 L) and transferred into a 12 L separatory funnel. The mixture was stirred, while 10% HCl (150 mL) was added by careful monitoring of temperature (maximum temp 35° C.) by an ice bath. The organic layer was washed with ice cold 10% HCl (8×500 mL), with saturated NaHCO3, dried (MgSO4) and concentrated under reduced pressure. The pale yellow solid was dried at 40° C. overnight to give the 3-acetylated compound 111 (223 g; 99%). 1H NMR (300 MHz, CDCl3) δ: 0.58(s, 3H), 0.81(s, 3H), 2.01(s, 3H), 2.10(s, 3H), 2.51(t, 1H, J=9 Hz), 4.67(sept, 1H, J=5 Hz).

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