反应详情

To a solution of 3-hydroxy-2-nitrobenzoic acid methyl ester (11 g) in chloroform (220 ml) was added dropwise bromine (18.7 g). The reaction mixture was heated at reflux for 16 hours. The reaction mixture was allowed to cool to ambient temperature and the reaction quenched by addition of aqueous sodium metabisulfite (22 g in 100 ml water) and the mixture was stirred for 15 minutes. The phases were separated and the organic phase was washed with brine, dried over sodium sulfate and concentrated. The residue was crystallized from diethyl ether/heptane to give 4-bromo-3-hydroxy-2-nitro-benzoic acid methyl ester (6.6 g). 1H-NMR (400 MHz, CDCl3): 9.92 (s, 1H), 7.84 (d, 1H), 7.09 (d, 1H), 3.93 (s, 3H) ppm.

1. temperatureThe reaction mixture was heated
2. temperatureat reflux for 16 hours
3. customthe reaction quenched by addition of aqueous sodium metabisulfite (22 g in 100 ml water)
4. customThe phases were separated
5. washthe organic phase was washed with brine
6. dry with materialdried over sodium sulfate
7. concentrationconcentrated
8. customThe residue was crystallized from diethyl ether/heptane