To a stirred mixture of 3α-acetoxy-5α-pregnan-20-one (120 mg, 360.5 g/m, 0.32 mmol) in 25 mL of dry benzene, was added 4.6 mL of 3M methylmagnesium bromide dropwise. After the addition of methylmagnesium bromide was completed, the reaction mixture was allowed to stir at room temperature for 18 h and then refluxed for 2 h. The excess methylmagnesium bromide was decomposed by dropwise addition of 30 mL of saturated ammonium chloride solution in an ice bath. The solution product was poured into water and extracted with chloroform twice. The extracts were dried over magnesium sulfate and evaporated to give 110 mg of crude product. The product was recrystallized in methanol to give 83 mg of 3α,20-dihydroxy-20-methyl-5α-pregnane.
