Triethylamine → 17-Acetylthiomethyl-1alpha,3beta-bis(tert-butyldimethylsilyloxy)androsta-5,7,16-triene

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Reaction Steps

To a solution of 1α,3β-bis(tert-butyldimethylsilyloxy)-17-(hydroxymethyl)androsta-5,7,16-triene (4.00 g, 7.34 mmol) in tetrahydrofuran (70 ml), triethylamine (4.10 ml, 29.4 mmol) was added and methanesulfonyl chloride (1.70 ml, 22.0 mmol) was further added dropwise at −10° C., followed by stirring for 20 minutes. After warming to room temperature, a solution of potassium thioacetate (3.73 g, 29.4 mmol) in dimethyl sulfoxide (70 ml) was added to the reaction mixture. The reaction mixture was stirred for 30 minutes, diluted with hexane, washed with water and then dried over anhydrous magnesium sulfate. After evaporation under reduced pressure to remove the solvent, the resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate=15:1) to give the titled compound (3.91 g, 88%) as a colorless oil.

Provenance & Evidence