反应详情

50.5 g (250 mmol) of the resulting 2,4-difluoro-O-ethoxycarbonylphenol was dissolved in 115 ml of concentrated sulfuric acid, 15.9 ml of fuming nitric acid was added while maintaining the internal temperature at from 10° to 20° C. and the mixture was stirred at the same temperature for 1 hour. The reaction solution was poured into ice water and the mixture was extracted with 500 ml of ethyl acetate. The organic layer was washed twice with an aqueous saturated solution of sodium chloride and dried over anhydrous sodium sulfate and the solvent was distilled off under reduced pressure. The residue was dissolved in 1.0 liter of methanol, 50 ml of water and 40 g of sodium bicarbonate were added and the mixture was stirred at room temperature for 16 hours. The reaction solution was filtered, methanol was distilled off under reduced pressure, and the mixture was adjusted to pH 5 by addition of 200 ml of water thereto and extracted twice with 200 ml of ethyl acetate. The organic layer was washed once with 400 ml of water and once with 400 ml of an aqueous saturated solution of sodium chloride and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to give 41.6 g (95%) of 2,4-difluoro-5-nitrophenol.

1. temperaturewhile maintaining the internal temperature at from 10° to 20° C.
2. extractionthe mixture was extracted with 500 ml of ethyl acetate
3. washThe organic layer was washed twice with an aqueous saturated solution of sodium chloride
4. dry with materialdried over anhydrous sodium sulfate
5. distillationthe solvent was distilled off under reduced pressure
6. dissolutionThe residue was dissolved in 1.0 liter of methanol
7. addition50 ml of water and 40 g of sodium bicarbonate were added
8. stirringthe mixture was stirred at room temperature for 16 hours
9. filtrationThe reaction solution was filtered
10. distillationmethanol was distilled off under reduced pressure
11. additionthe mixture was adjusted to pH 5 by addition of 200 ml of water
12. extractionextracted twice with 200 ml of ethyl acetate
13. washThe organic layer was washed once with 400 ml of water and once with 400 ml of an aqueous saturated solution of sodium chloride
14. dry with materialdried over anhydrous sodium sulfate
15. distillationThe solvent was distilled off under reduced pressure