反应详情

To a solution of the product from Step D (26 mg, 0.1 mmol) in 1,2-dichloroethane (10 mL) was added boron tribromide-methylsulfide complex (1.0 M, 1.0 mL, 1.0 mmol) and the solution stirred at reflux for 72 h. The solution was poured into aqueous NaHCO3, and extracted with ethyl acetate (2×20 mL). The combined extracts were dried (MgSO4) concentrated to a residue, which was purified by chromatography (silica, gradient, 10 to 25% methanol in dichloromethane) to furnish a solid (8 mg, 32%): 1H NMR (CDCl3) δ 8.30 (d, J=9.0 Hz, 1H), 7.99 (s, 1H), 7.60 (d, J=8.4 Hz, 1H), 7.35 (d, J=9.0 Hz, 1H), 7.29 (d, J=2.4 Hz, 1H), 7.21 (dd, J=9.0, 2.4 Hz, 1H), 3.6 (m, 1H), 3.3 (m, 2H), 1.25 (d, J=6.6 Hz, 3H); MS m/z 242 [M+H]+.

1. temperatureat reflux for 72 h
2. extractionextracted with ethyl acetate (2×20 mL)
3. dry with materialThe combined extracts were dried (MgSO4)
4. concentrationconcentrated to a residue, which
5. customwas purified by chromatography (silica, gradient, 10 to 25% methanol in dichloromethane)