反应详情

3.7 g (13 mmol) of 3-(2,4-difluorophenyl)-1-methyl-6-trifluoromethyl-2(1H)-pyridone was dissolved in 20 ml of sulfuric acid, and 0.9 g (14 mmol) of fuming nitric acid was dropwise added thereto under cooling with ice, followed by stirring for 30 minutes under cooling with ice. The reaction solution was poured into ice water and extracted with ethyl acetate. The organic layer was washed with an aqueous sodium hydrogencarbonate solution and water and then, dried over anhydrous magnesium sulfate. Ethyl acetate was distilled off under reduced pressure, and then, the obtained residue was purified by silica gel column chromatography to obtain 4.2 g (yield: 98%) of the desired product. Melting point: 115-118° C.

1. temperatureunder cooling with ice
2. temperatureunder cooling with ice
3. extractionextracted with ethyl acetate
4. washThe organic layer was washed with an aqueous sodium hydrogencarbonate solution and water
5. dry with materialdried over anhydrous magnesium sulfate
6. distillationEthyl acetate was distilled off under reduced pressure
7. customthe obtained residue was purified by silica gel column chromatography