反应详情

To a 0° C. solution of 2,6-dimethyl-4-nitrophenol (3 g, 17.9 mmol) and pyridine (4.25 g, 53.7 mmol) in dichloromethane (30 mL) was slowly added triflic anhydride (7.6 g, 26.8 mmol). The solution was stirred at room temperature for 2 h. The mixture was concentrated poured into water (50 mL) and extracted with ethyl acetate (50 mL×3). The organic layer was dried over anhydrous Na2SO4 and concentrated under reduced pressure to give crude 2,6-dimethyl-4-nitrophenyl trifluoromethanesulfonate (5.5 g) as a yellow solid. To a 0° C. solution of 4-(trifluoromethyl)-1H-imidazole (1.82 g, 13.4 mmol) in DMF (20 mL) was added sodium hydride (0.81 g, 20.1 mmol). The mixture was stirred at room temperature for 1 h. The crude 2,6-dimethyl-4-nitrophenyl trifluoromethanesulfonate prepared above (4.0 g, 13.4 mmol) was added. The mixture was stirred at 80° C. for 12 h. The reaction was diluted with water and extracted with ethyl acetate (30 mL×3). The organic layer was dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude material was purified by silica gel chromatography to give 1-(2,6-dimethyl-4-nitrophenyl)-4-(trifluoromethyl)-1H-imidazole (805 mg, 21%) as a colorless solid. 1H NMR (400 MHz, CDCl3) δ 8.01 (s, 2H), 7.47 (s, 1H), 7.23 (s, 1H), 2.11 (s, 6H).

1. additionwas added
2. stirringThe mixture was stirred at 80° C. for 12 h
3. extractionextracted with ethyl acetate (30 mL×3)
4. dry with materialThe organic layer was dried over anhydrous Na2SO4
5. concentrationconcentrated under reduced pressure
6. customThe crude material was purified by silica gel chromatography