反应详情

温度

5 °C

4-Bromo-3-methylphenol(4.49 g, 24.0 mmol), t-butyldimethylsilyl chloride (5.43 g, 36.0 mmol) and imidazole (4.90 g, 22.0 mmol) in N,N-dimethylformamide (30 ml) were stirred at room temperature for 16 h. Water (100 ml) was added and the products extracted with ethyl acetate. Drying (MGSO4), evaporation to dryness under reduced pressure and purification by flash chromatography using hexane as eluent gave the crude silylated phenol (4.16 g, 57%), to this crude product (4.16 g, 13.77 mmol) was added N-Bromosuccinimide (2.70 g, 15.15 mmol) and carbon tetrachloride (100 ml). The mixture was heated to reflux over a 150 W light bulb for 2 h. Cooling to 5° C., filtration, evaporation of the filtrate to dryness under reduced pressure and purification by flash chromatography using hexane as eluent gave the title compound as a colourless oil: δH (CDCl3) 0.20 [6H, s, Si(CH3)2 ], 0.97 (9H, s, t bu), 4.50 (2H, s, CH2Br), 6.63 (1H, dd, J 2.9 and 8.5 Hz, 4-H), 6.91 (1H, d, J 2.9 Hz, 5-H), 7.37 (1H, d, J 8.5 Hz, 3-H); m/z (E.I.) 382 (M+, 5%), 380 (M+, 10%), 378 (M+, 5%); (Found: M+, 377.9642. C13H20Br2OS; requires M, 377.9652).

1. extractionthe products extracted with ethyl acetate
2. customDrying
3. custom(MGSO4), evaporation to dryness
4. customunder reduced pressure and purification by flash chromatography
5. customgave the crude silylated phenol (4.16 g, 57%)
6. temperatureThe mixture was heated
7. temperatureto reflux over a 150 W light bulb for 2 h
8. filtrationfiltration, evaporation of the filtrate to dryness
9. customunder reduced pressure and purification by flash chromatography