反应详情

To a solution of β-39 (4.0 g, 5.93 mmol) in toluene (40 mL) were added 1,2-dibromethane (0.8 mL, 8.90 mmol), tetrabutylammonium bromide (0.4 g, 1.19 mmol) and aq. 50% NaOH solution (40 mL). The mixture was stirred at room temperature for 15 h. After dilution with water, the mixture was extracted with EtOAc. The organic layer was dried over anhydrous MgSO4, filtered and concentrated in vacuo. The residue was purified by silica column chromatography to provide the titled compound 42 (3.0 g, 71%).

1. extractionAfter dilution with water, the mixture was extracted with EtOAc
2. dry with materialThe organic layer was dried over anhydrous MgSO4
3. filtrationfiltered
4. concentrationconcentrated in vacuo
5. customThe residue was purified by silica column chromatography