反应详情

To a solution of 17 (3.7 g, 16.8 mmol) in dry dichloromethane (42 mL) at 0° C. was added boron tribromide (3.17 mL, 33.5 mmol). The mixture was stirred vigorously at room temperature for 16 h, cooled down to 0° C. Ice-water was poured-in and the stirring was continued for 30 min. The reaction mixture was concentrated to form a precipitate which was collected by filtration, washed with water, dried and purified by flash chromatography on silica gel (MeOH/CH2Cl2: 2/98) to afford the title compound 18 (3.28 g, 15.9 mmol, 94% yield). 1H NMR: (400 MHz, DMSO-d6) δ (ppm): 10.26 (s, 1H), 8.66 (d, J=5.6 Hz, 1H), 8.05 (td, J=8.4, 1.6 Hz, 2H), 7.96 (d, J=5.6 Hz, 1H), 6.90 (td, J=8.4, 1.6 Hz, 2H).

1. temperaturecooled down to 0° C
2. waitwas continued for 30 min
3. concentrationThe reaction mixture was concentrated
4. customto form a precipitate which
5. filtrationwas collected by filtration
6. washwashed with water
7. customdried
8. custompurified by flash chromatography on silica gel (MeOH/CH2Cl2: 2/98)