反应详情

A suspension of the product of Step A (5.5 g 23.4 mmol) in 10 mL of CCl4 was heated to reflux. N-bromosuccinimide (4.6 g, 25.7 mmol) and several crystals (approximately 100 mg) of azoisobutyronitrile (AIBN) were added. The resultant solution was stirred at reflux for 4 hours. The solution was cooled, diluted with 1.5 L of CH2Cl2 and washed with 400 mL of H2O and 400 mL of brine. The organic phase was dried over MgSO4, filtered and concentrated to a brown oil. The resultant oil was flash chromatographed eluting with 10:1 hexane/ethyl acetate to afford the titled compound (5.6g, 80%) as a yellow powder.

1. temperaturewas heated to reflux
2. temperatureat reflux for 4 hours
3. temperatureThe solution was cooled
4. washwashed with 400 mL of H2O and 400 mL of brine
5. dry with materialThe organic phase was dried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated to a brown oil
8. customchromatographed
9. washeluting with 10:1 hexane/ethyl acetate