反应详情

E2 (312 mg, 0.74 mmol) was dissolved in 18 mL of anhydrous dichloromethane. BBr3 (3.7 mL, 1M in dichloromethane) was added dropwise at −10° C. under nitrogen. Stirring was continued at −10° C. for 50 min., then at room temperature for 45 min. Water was added to quench the reaction. The dichloromethane layer was set aside. The aqueous layer was adjusted to pH 8 with sodium bicarbonate and extracted with 30% isopropanol in chloroform 4 times. The dichloromethane layer was washed with brine and the brine layer was adjusted to pH 8 with sodium bicarbonate and extracted with 30% isopropanol in chloroform 1 times. The combined 30% isopropanol in chloroform extracts were dried and concentrated to give 222 mg of E3 as a solid, which was used directly for next step.

1. waitat room temperature for 45 min
2. customto quench
3. customthe reaction
4. extractionextracted with 30% isopropanol in chloroform 4 times
5. washThe dichloromethane layer was washed with brine
6. extractionextracted with 30% isopropanol in chloroform 1 times
7. dry with materialThe combined 30% isopropanol in chloroform extracts were dried
8. concentrationconcentrated