反应详情

A suspension of 21-methylene-20(R)-methylpregn-4-en-3-one (5, 100.0 mg, 0.3063 mmol) and lithium tri-t-butoxyaluminohydride (319.4 mg, 1.256 mmol) in 5 mL of anh. THF was stirred under argon for 6 h, after which water (48 μL), 15% (w/w) sodium hydroxide (48 μL), and water (143 μL) were added. The mixture was filtered through diatomaceous earth and the residue was extracted four times with 5 mL aliquots of THF. Concentration of the combined filtrates under reduced pressure and two-fold recrystallization from aqueous ethanol gave white platelets (42.6 mg, 0.130 mmol, 42%), m.p. 121-123° C. TLC (25% ethyl acetate/hexanes on silica gel) shows major product at Rf 0.38 and minor product at Rf 0.43 (starting material Rf 0.50).

1. filtrationThe mixture was filtered through diatomaceous earth
2. extractionthe residue was extracted four times with 5 mL aliquots of THF
3. customConcentration of the combined filtrates under reduced pressure and two-fold recrystallization from aqueous ethanol
4. customgave white platelets (42.6 mg, 0.130 mmol, 42%), m.p. 121-123° C