反应详情

[step 1] To a mixture of 4-bromo-2-methylaniline (9.00 g, 48.3 mmol) and acetic anhydride (54 mL) was added dropwise under ice-cooling fuming nitric acid (8.10 mL, 194 mmol) over 20 min. Under ice-cooling, the mixture was stirred for 1 hr and water and ethyl acetate were added to the mixture, and the mixture was extracted. The organic layer was washed with saturated aqueous sodium hydrogen carbonate solution and brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. Ethyl acetate-hexane (1/1, 24 mL) was added to the residue, and the precipitated solid was collected by filtration. The obtained solid was suspended in ethanol (40 mL), concentrated hydrochloric acid (25 mL) was added, and the mixture was stirred under reflux for 4 hr. To the mixture were added ethanol (10 mL) and water (7 mL), and the mixture was stirred at 90° C. for 30 min. The reaction solution was allowed to cool to room temperature, and the precipitated solid was collected by filtration to give 4-bromo-6-methyl-2-nitroaniline (3.87 g, 35%).

1. additionwas added dropwise under ice-
2. temperatureUnder ice-cooling
3. extractionthe mixture was extracted
4. washThe organic layer was washed with saturated aqueous sodium hydrogen carbonate solution and brine
5. dry with materialdried over anhydrous magnesium sulfate
6. concentrationconcentrated under reduced pressure
7. additionEthyl acetate-hexane (1/1, 24 mL) was added to the residue
8. filtrationthe precipitated solid was collected by filtration
9. additionconcentrated hydrochloric acid (25 mL) was added
10. stirringthe mixture was stirred
11. temperatureunder reflux for 4 hr
12. additionTo the mixture were added ethanol (10 mL) and water (7 mL)
13. stirringthe mixture was stirred at 90° C. for 30 min
14. filtrationthe precipitated solid was collected by filtration