反应详情

Sodium nitrate (28 g, 0.33 mmol) was dissolved in the solvent mixture of 70 mL of concentrated sulfuric acid and 210 mL of water at −5° C., followed by slowly dropwise addition of 2-bromo-4-methyl-phenol 11a (30.8 g, 0.165 mol). The reaction mixture was reacted for 2 hours upon cooling by an ice-water bath. The mixture was warmed up to room temperature and reacted for another 1 hour. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was extracted with 200 mL of ethyl acetate. The combined organic extracts were washed with water (100 mL×5), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to obtain the title compound 2-bromo-4-methyl-6-nitro-phenol 11b (22.24 g, yield 58.1%) as a yellow solid.

1. customThe reaction mixture was reacted for 2 hours
2. temperatureupon cooling by an ice-water bath
3. customreacted for another 1 hour
4. extractionThe mixture was extracted with 200 mL of ethyl acetate
5. washThe combined organic extracts were washed with water (100 mL×5)
6. dry with materialdried over anhydrous sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure
9. customThe residue was purified by silica gel column chromatography