反应详情

4-Bromo-3-chloro-2-nitroaniline (4.78 g, 19.01 mmol) was dissolved in ethanol (112 mL). Tin (II) chloride (14.42 g, 76 mmol) was added, and the resulting mixture was stirred at reflux for 12 hours. The mixture was cooled to room temperature, poured into water, and adjusted to pH 5 with saturated sodium bicarbonate solution. The resulting solid was filtered and rinsed well with ethyl acetate. The filtrate was washed with water and brine, dried over Na2SO4, filtered and concentrated in vacuo. The crude product was purified by column chromatography on silica gel using a solvent gradient of 0-50% EtOAc in hexane to give the title compound (3.32 g, 79%). 1H NMR (400 MHz, CDCl3) δ ppm 6.94 (d, 1H), 6.51 (d, J=7.0, 1H), 3.87 (br s, 2H), 3.46 (br s, 2H).

1. temperatureat reflux for 12 hours
2. filtrationThe resulting solid was filtered
3. washrinsed well with ethyl acetate
4. washThe filtrate was washed with water and brine
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customThe crude product was purified by column chromatography on silica gel using a solvent gradient of 0-50% EtOAc in hexane