Dichloromethane → HCID 20637860, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 2-ethynylpyridine (270 mg, 2.6 mmol) in dry THF (15 mL) was treated with a n-BuLi (2.5 M in THF, 2.5 mmol, 1 mL) at −60° C. After stirring the mixture at −78° C. for 0.5 hr, a solution of 5β-pregnan-3,20-dione, cyclic 20-(1,2-ethanediyl acetal)170 mg, 047 mmol) in THF (15 mL) was added and the mixture was stirred at −78° C. for 1 hr. The cooling bath was removed and the mixture was quenched with NH4Cl solution (3 mL). The solvent was removed and the residue was then dissolved in acetone (25 mL). After adding 2N HCl (2 mL) the solution was stirred at rt for 15 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 (360 mg). This crude product was then dessolved in a small amount of CH2Cl2 and poured on a column of silica gel. Elution with toluene:acetone mixture (95:5) gave the unreacted ethynlpyridine as a first fraction. Further elution with the same solvent mixture yielded 3β-(2-pyridyl)ethynyl-3α-hydroxy-5β-pregnan-20-one (107 mg) as a colorless solid; mp 192-195° C.; TLC Rf (toluene:acetone 87:13)=0.21.

Provenance & Evidence