TBAF tetrahydrofuran → 1alpha,3beta-Dihydroxy-17-(4-hydroxy-4-methylpentyloxymethyl)androsta-5,7,16-triene

Participants

Reaction Steps

To a solution of 1α,3β-bis(tert-butyldimethylsilyloxy)-17-(4-triethylsilyloxy-4-methylpentyloxymethyl)androsta-5,7,16-triene (278.7 mg, 0.367 mmol) in tetrahydrofuran (2 ml), was added a 1M tetra-n-butylammonium fluoride tetrahydrofuran solution (3.3 ml, 3.3 mmol), followed by reflux under heating for 14 hours. The reaction solution was diluted with ethyl acetate, washed with 5% hydrochloric acid, a saturated aqueous sodium bicarbonate solution and saturated brine in that order, the organic layer was dried over anhydrous magnesium sulfate and evaporated under reduced pressure to remove the solvent. The thus obtained residue was purified by column chromatography (dichloromethane:ethanol=10:1) and preparative thin layer chromatography (4 sheets (each 0.5 mm thickness), dichloromethane:ethanol=20:1, developed twice, and then dichloromethane:ethanol=10:1, developed twice) to give the titled compound (56.3 mg, 37%) as a colorless foam.

Provenance & Evidence