反应详情

To a solution of the product from Step D (0.56 g, 0.23 mmol) in 1,2-dichloroethane (10 mL) was added boron tribromide-methylsulfide complex in THF solution (1.0M, 0.5 mL, 0.5 mmol) and the solution heated to reflux for 16 h. The solution was allowed to cool, poured into aqueous NaHCO3, extracted with chloroform (2×20 mL), dried (Na2SO4) and concentrated. The crude product was purified by chromatography (silica, 20% methanol in dichloromethane) to give a solid (0.007 g, 13%): 1H NMR (CDCl3) δ 7.39 (m, 2H), 7.00 (s, 1H), 6.79 (dd, J=8.4, 2.4 Hz, 1H), 4.30 (dd, J=13.8, 4.8 Hz, 1H), 4.14 (dd, J=13.8, 7.8 Hz, 1H), 3.55 (m, 1H), 3.48 (bm, 4H), 1.19 (d, J=6.6 Hz, 3H); MS m/z 230 [M+H]+.

1. temperaturethe solution heated
2. temperatureto reflux for 16 h
3. temperatureto cool
4. extractionextracted with chloroform (2×20 mL)
5. dry with materialdried (Na2SO4)
6. concentrationconcentrated
7. customThe crude product was purified by chromatography (silica, 20% methanol in dichloromethane)