4,5α-dihydro-2-(hydroxymethylene)testosterone (oxystanolone) is obtained by reacting 2-Hydroxymethylene-androstan-17β-((tetrahydro-2H-pyran-2-yl)oxy)-3-one with pyridinium tosylate.
Procedure: To a solution of 0.95 g intermediate (2) in 55 ml of the solvent mixture
tetrahydrofuran/methanol/water 7:2:1 pyridinium tosylate (1.15 g dissolved in 20 ml
tetrahydrofuran/methanol/water 7:2:1) was added at room temperature. Subsequently, this was
followed by 8 h stirring at 50°C. Monitoring via TLC still shows remaining starting material.
After evaporation of all solvents, the crude product was chromatographed on silica gel by using
hexane-ethyl acetate (8:2). 0.385 g of 5 was obtained as a colorless solid (52%).
