N-Bromoacetamide → 4beta-Bromo-24,24-difluoro-25-hydroxy-5beta-cholestan-3-one

Participants

Reaction Steps

To a solution of 800 mg of 24,24-difluoro-5β-cholestane-3α,25-diol (Va) in 32 ml of tert-butyl alcohol, 15 ml of water, 200 μl of 48% hydrobromic acid and 800 mg of N-bromoacetamide were added. After stirring at room temperature for 3 days, ethyl acetate was added to the reaction mixture, which was then washed sequentially with 0.5% aqueous sodium thiosulfate and saturated aqueous sodium chloride, and dried over anhydrous magnesium sulfate. The solvent was distilled off, and the resulting residue was purified through a short column (5 g of silica gel) to produce 950 mg of a crude product. The product was recrystallized from ether/hexane to produce 4β-bromo-24,24-difluoro-25-hydroxy-5β-cholestan-3-one.

Provenance & Evidence