反应详情

To a solution of 156 (500 mg, 1.7 mmol) in dichloromethane (20 mL) and water (5 mL) was added 2,2,6,6-tetramethylpiperidinooxy (13 mg, 0.08 mmol), tetrabutylammonium bromide (27 mg, 0.08 mmol), potassium bicarbonate (788 mg, 7.9 mmol) and N-bromosuccinimide (342 mg, 1.9 mmol). The resulting solution was stirred for 30 minutes at room temperature, before the reaction was quenched by the addition of saturated aqueous sodium sulfite solution (10 mL), which was then extracted with dichloromethane (2×10 mL). The combined organic layer was washed with brine (2×10 mL), dried over sodium sulfate, filtered and concentrated under vacuum. The crude residue was purified by flash column chromatography with 10% ethyl acetate in dichloromethane to afford 157 as an off-white solid (300 mg, 54%). (ES, m/z): [M+H]+ 287.0; 1H NMR (300 MHz, CDCl3) δ 9.82 (s, 1H), 6.34 (d, J=6.0 Hz, 1H), 4.37-4.32 (m, 1H), 4.11-4.05 (m, 1H), 3.94-3.82 (m, 1H), 3.61-3.54 (m, 1H), 3.36-3.23 (m, 1H), 3.08 (s, 6H), 1.46 (s, 6H).

1. customwas quenched by the addition of saturated aqueous sodium sulfite solution (10 mL), which
2. extractionwas then extracted with dichloromethane (2×10 mL)
3. washThe combined organic layer was washed with brine (2×10 mL)
4. dry with materialdried over sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated under vacuum
7. customThe crude residue was purified by flash column chromatography with 10% ethyl acetate in dichloromethane