Estra-1,3,5(10),16-tetraen-3-ol → Estra-1,3,5(10),6,8,16-hexaen-3-ol

Participants

Reaction Steps

To a cooled (ice water bath) solution of crude estra-1,3,5(10)6,8-pentaen-3-ol 17-(p-toluenesuffonyl)hydrozone (7, 1.0887 g, ≤2463 mmol) in anh. THF (25 ml) under argon was added n-butyllithium (2.5 M in hexane, 3.9 ml, 9.8 mmol) dropwise with stirring over 2 min. See FIG. 159. Stirring was continued 3 days, during which the reaction was allowed to gradually warm to room temperature. 50 ml of 1 hydrochloric acid-ice were added and the mixture was extracted three times with 25 ml portions of ether. The combined organic extracts were washed with 50 ml of brine, dried over magnesium sulfate, and filtered through diatomaceous earth. The residue was washed 10 ml of ether and the combined filtrates were concentrated under reduced pressure. Flash chromatography (20% ethyl acetate/hexanes on silica gel) and recrystallization from aqueous ethanol with charcoal decolorization gave tan platelets (245.8 mg, 0.9819 mmol, 40%), m.p. 162-163° C.

Provenance & Evidence