反应详情

Dissolve 16-dehydropregnenolone (5.00 g, 15.90 mmol) and 5,5-dibromobarbituric acid (4.55 g, 15.90 mmol) in tetrahydrofuran (60 mL). Add concentrated aqueous hydrogen bromide (100 μL of a 48% solution) to the stirring solution and heat the reaction at reflux for 1 hour. Cool slightly and then concentrate under vacuum to produce a brown oily foam. Dissolve the residue in methylene chloride (350 mL), rinse with 50% saturated sodium bicarbonate (2×200 mL), brine (125 mL), dry over anhydrous magnesium sulfate, filter and concentrate under vacuum to provide 21-bromo-3β-hydroxypregna-5,16-dien-20-one (6.53 g) as an orange-brown solid, slightly contaminated with starting material.

1. temperatureheat
2. customthe reaction
3. temperatureat reflux for 1 hour
4. temperatureCool slightly
5. concentrationconcentrate under vacuum
6. customto produce a brown oily foam
7. washrinse with 50% saturated sodium bicarbonate (2×200 mL), brine (125 mL)
8. dry with materialdry over anhydrous magnesium sulfate
9. filtrationfilter
10. concentrationconcentrate under vacuum