反应详情

3-fluoro-4-methylphenol (3.66 g, 29.0 mmol) was dissolved in dichloroethane (32 mL) and tetrabutylammonium bromide (0.935 g, 2.90 mmol) was added. Nitric acid 70% (3.7 mL, 58 mmol) was diluted with water (33 mL) to make a 7% nitric acid solution. This solution was added to the reaction mixture which was then stirred at room temperature for 4 h at which time the reaction was judged complete by TLC. The reaction was poured into water and extracted with dichloromethane (3×). The combined organic layers were dried over magnesium sulfate, filtered and concentrated in vacuo. The resulting residue was absorbed onto silica gel and purified by chromatography on SiO2 to give 5-fluoro-4-methyl-2-nitrophenol as a yellow solid (2.83 g, 57%). 1H NMR (400 MHz, DMSO-d6) δ ppm 11.10 (s, 1 H), 7.89 (d, J=8.1 Hz, 1 H), 6.85 (d, J=11.0 Hz, 1 H), 2.13 (s, 3 H).

1. additionThis solution was added to the reaction mixture which
2. extractionextracted with dichloromethane (3×)
3. dry with materialThe combined organic layers were dried over magnesium sulfate
4. filtrationfiltered
5. concentrationconcentrated in vacuo
6. customThe resulting residue was absorbed onto silica gel
7. custompurified by chromatography on SiO2