Nitric Acid → 3-(2,4-difluoro-5-nitrophenyl)-1-methyl-6-trifluoromethyl-2(1H)-pyridone

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Reaction Steps

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. 1H-NMR (400 MHz, CDCl3) δ value: 3.71(3H,s), 6.81(1H,d), 7.13(1H,t), 7.57(1H,d), 8.43(1H,m)ppm.

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