Boron tribromide → 4-Bromo-3-nitrophenol

Temperature

-78 °C

4-Bromo-3-nitroanisole (2.32g, 10 mmol) was dissolved in 25 mL dichloromethane and cooled in an acetone-dry ice bath at −78° C. under nitrogen. A solution of BBr3 (1.0M in dichloromethane) (25 mL, 25 mmol) was added dropwise. Gradually increased temperature to 20° C., stirred for 30 h. The reaction mixture was cooled to 0° C. and distilled water (30 mL) was added dropwise. The aqueous layer was extracted with ethyl acetate (30 mL×2) . The combined organic layer was washed successively with saturated NaHCO, solution (30 mL×2). The organic layer was dried over anhydrous sodium sulfate, filtered and evaporated in vacuo. The residue was chromatographed over 100 g of silica gel using 3:1 mixture respectively of hexanes and ethyl acetate to give the phenol in 70% yield; 1H NMR(CDCl3) δ6.92(1H, dd, J1=2.9, J2=8.8), 7.36(1H, d, J=2.9), 7.56(1H, d, J=8.8); 13C NMR(CDCl3) δ105.2 113.4, 116.4, 121.4, 136.3, 155.9; HRMS calcd for C6H4NO3Br: 216.9374, found: 216.9375.

1. temperatureThe reaction mixture was cooled to 0° C.
2. distillationdistilled water (30 mL)
3. additionwas added dropwise
4. extractionThe aqueous layer was extracted with ethyl acetate (30 mL×2)
5. washThe combined organic layer was washed successively with saturated NaHCO, solution (30 mL×2)
6. dry with materialThe organic layer was dried over anhydrous sodium sulfate
7. filtrationfiltered
8. customevaporated in vacuo
9. customThe residue was chromatographed over 100 g of silica gel using 3:1 mixture respectively of hexanes and ethyl acetate

ORD record

ord-8000d736ae2b41f8ba391ea2d2d3c0db

Source dataset

uspto-grants-2002_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06486167B1