PREGNANE-3,20-DIONE, (5.BETA.)- → HCID 22212686, compound

Participants

Reaction Conditions

Reaction Steps

A solution of propargyl 4-pyridyl ether (prepared according to (Thummel et al, J. Org. Chem. 1978, 43 4882) (173 mg, 1.3 mmol) in dry THF (15 mL) was treated with n-BuLi (2.5M in THF, 1,3 mmol, 0.52 mL) at −70° C. After stirring the mixture at −75° C. for 0.5 hr, a solution of 5β-pregnan-3,20-dione, cyclic 20-(1,2-ethanediyl acetal) (180 mg, 0.5 mmol) in THF (15 mL) was added and the mixture was stirred at −78° C. for 20 min. The cooling bath was removed and the stirring was continued at rt for 1 hr. The mixture was quenched with NH4Cl solution (2 mL). The solvent was removed and the residue was then dissolved in acetone (25 mL). After adding 2N HCl (2 mL) the s olution was stirred at rt for 20 min. Sat. NaHCO3 soln. was added to neutralize the acid. The solvents were removed and the residue was extracted with EtOAc. The organic layer was washed with water, and brine. After drying over anhyd. MgSO4 the solution was filtered and evaporated to yield the crude product (250 mg). This crude product was then dissolved in a small amount of CH2Cl2 and poured on a column of silica gel. Elution with CH2Cl2:acetone mixture (90:10) gave 3α-hydrocy-3β-[3-4′-pyridinyloxy)-1-propynyl]-5β-pregnan-20-one (145 mg) as a colorless solid; mp 84-90° C.; TLC Rf (CH2Cl2:acetone 85:15)=0.17.

Provenance & Evidence