Tetrahydrofuran → 21-Desacetoxy-21-Chloro Anecortave

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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), THF (60 ml), methanol (12 ml) and acetone (9 ml) are cooled to 0° under nitrogen and sodium methoxide in methanol (25%, 2.8 ml) are added. After one hour, by TLC analysis, complete conversion to the 20-methoxy derivative (VIII) had occurred. The resulting mixture is brought to 28° and stirred for 22 hours and then warmed to 30°-35° for five hours. The mixture is diluted with water (150 ml) and then 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 slurried in methylene chloride (15 ml) and treated with aqueous hydrochloric acid (6 N, 1 ml) at 30°-35° for one hour. The mixture is diluted with methylene chloride (25 ml) and extracted with water (2× 10 ml). The organic layer is separated, dried over sodium sulfate and concentrated under reduced pressure to give the crude product. This material is purified by trituration with hexane/ethyl acetate (7/3, 25 ml) to give the title compound, mp 210.5°-212°; NMR (CDCl3) 0.63, 1.33, 4.47, 5.53 and 5.72δ. ##STR2##

Provenance & Evidence