Bromine → HCID 86754250, compound

Participants

Reaction Steps

A solution of 3β-ethynyl-3α-hydroxy-5β-pregnan-20-one 3 g, 8.77 mmol) in MeOH (110 mL) was treated with two drops of HBr (48%), followed by bromine (0.5 mL, 10.8 mmol). The mixture was stirred at room temperature for 1 hr and was poured into ice-water. The separated solid was collected by filtration, washed with water, and dried (3.2 g). This semi-dried solid was then dissolved in EtOAc and dried over anhyd. MgSO4. Filtration and removal of the solvent gave the crude bromo derivative. This crude product was then dissolved in a small amount of CH2Cl2 and poured on a column of silica gel. Elution with hexane:EtOAc mixture (4:1) gave 21-bromo-3β-ethynyl-3α-hydroxy-5β-pregnan-20-one (3.2 g).

Provenance & Evidence