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温度

0 °C

To a solution of 4-bromo-3-fluorophenol (89 g, 465.9 mmol) in a mixture of CH2Cl2 (940 mL) and H2SO4 (52.1 mL, 978 mmol) at 0° C., HNO3 (65%) (32.9 ml, 468 mmol) was added dropwise (the mixture turned from colourless to black). The resulting mixture was stirred at 0 ° C. for 1 h and then poured into water. The organic layer was washed with brine, dried (Na2SO4) and the solvent was evaporated under reduced pressure to afford the crude compound which was purified by flash chromatography (SiO2, heptane/toluene 1:3) to give 4-bromo-5-fluoro-2-nitrophenol (49.5 g, 45%). 1H-NMR (400 MHz, CDCl3) 6.95 (d, J=9.0, 1H), 8.38 (d, J=6.2, 1H), 10.69 (s, 1H).

1. washThe organic layer was washed with brine
2. dry with materialdried (Na2SO4)
3. customthe solvent was evaporated under reduced pressure
4. customto afford the crude compound which
5. customwas purified by flash chromatography (SiO2, heptane/toluene 1:3)