Tetrahydrofuran → 21-Chloro-17alpha-hydroxy-20-methoxypregna-4,9(11),20-trien-3-one

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Reaction Steps

20,21-Dichloro-21-(phenylsulfinyl)pregna-4,9(11),17(20)-trien-3-one (VII, Example 2, 3.0 g) dry THF (36 ml), methanol (7.5 ml) and acetone (6 ml) are cooled to 0° under nitrogen and sodium methoxide in methanol (25%, 2.8 ml) is added with stirring. After 1 hour of stirring, TLC analysis shows complete conversion of the dichloro starting material (VI) to 21-chloro-20-methoxy-21-(phenylsulfinyl)pregna-4,9(11),17(20)-trien-3-one (VIII, Example 3). The mixture is brought to 20°-25° and stirred for 22 hours and then warmed to 30°-35° for 5 hours. The mixture is diluted with water (100 ml) and extracted with ethyl acetate-methylene chloride (2×75 ml). The organic extracts are combined, washed with water, dried over sodium sulfate and concentrated under reduced pressure. The concentrate is triturated with hexane/ethyl acetate (85/15, 25 ml) to give the title compound, mp 197°-199°; NMR (CDCl3) 0.68, 1.35, 3.97, 5.55 and 5.73δ.

Provenance & Evidence