反应详情

To a solution of 3,5-dichloro-2,4-difluorobenzenamine (9.9 g, 50.0 mmol) in HBr (200 mL) was added a solution of NaNO2 (3.45 g, 50.0 mmol) in H2O (80 mL) slowly under salt ice-bath, then the mixture was stirred for 2 h, and CuBr (7.15 g, 50.0 mmol) was added at 0° C. The mixture was stirred for additional 2 h, and then poured into water (100 mL), extracted with DCM, dried over NaSO4, filtered and concentrated under reduced pressure. The resulting residue was purified by chromatography over silica gel eluted with PE to give compound 1-bromo-3,5-dichloro-2,4-difluorobenzene (6.2 g, yield 48%) as a colorless oil. 1H NMR (400 MHz, CDCl3): δ 7.49 (t, J=7.2 Hz, 1H) ppm.

1. stirringThe mixture was stirred for additional 2 h
2. extractionextracted with DCM
3. dry with materialdried over NaSO4
4. filtrationfiltered
5. concentrationconcentrated under reduced pressure
6. customThe resulting residue was purified by chromatography over silica gel
7. washeluted with PE