tert-Butanol → Estra-4,16-dien-3-one

Participants

Reaction Steps

To estra-1,3,5(10), 16-tetraene-3-methyl ether (551.5 mg., 2.055 mmol) in 8.6 ml of anhydrous THF, approximately 30 ml of anhydrous ammonia, and 6.76 g of t-butyl alcohol was added lithium wire (0.24 g, 35 mg-atom) cut in small pieces. The reaction mixture was refluxed 41/2 h under argon, after which methanol (2.3 ml) was added and the ammonia was allowed to boil off overnight. The residue was dissolved in 25 Ml of methanol and was acidified to approximately Ph 1 with 5N HCI. After heating in an oil bath between 55 and 70 C. for 15 min. the cooed hydrolysis mixture was partitioned between 25 ml of water and 50 ml of ethyl acetate and the aqueous phase was extracted with 25 ml of ethyl acetate. The combined organic extracts were washed with 25 ml of saturated sodium bicarbonate and 25 ml of brine, dried over magnesium sulfate, and filtered. Removal of solvent under reduced pressure yielded 0.57 g of oily residue which was purified by flash chromatography on silica gel (eluent: 15% ethyl acetate/hexane) followed by recrystallization from pentane to give crystals (206.1 mg, 39%) homogeneous to TLC, m.p. 67-71 C.

Provenance & Evidence