反应详情

2-Bromo-4-fluoro-5-nitro-benzoic acid methyl ester. To conc. fuming H2SO4 (8 mL) at 0° C. was added conc. fuming HNO3 (8 mL) and the mixture allowed to stand for 5 min. To a solution of 2-bromo-4-fluoro-benzoic acid methyl ester (9.32 g, 40 mmol) at 0° C., the mixture of acids was added dropwise over 30 min. The mixture was allowed to warm to RT and was stirred for 18 h. The mixture was poured into ice water, diluted with EtOAc, and treated with 6 N NaOH. The aqueous layer was extracted with EtOAc (3×300 mL). The combined organic layers were washed with brine (200 mL), dried (MgSO4), and concentrated. The crude material was purified on SiO2 (0-25% EtOAc/hexanes) to provide 4.9 g (43%) of the title compound. 1H NMR (500 MHz, CDCl3): 8.61 (d, J=8.0, 1H), 7.66 (d, J=10.0, 1H), 3.91 (s, 3H).

1. additionwas added dropwise over 30 min
2. extractionThe aqueous layer was extracted with EtOAc (3×300 mL)
3. washThe combined organic layers were washed with brine (200 mL)
4. dry with materialdried (MgSO4)
5. concentrationconcentrated
6. customThe crude material was purified on SiO2 (0-25% EtOAc/hexanes)