反应详情

Potassium carbonate (0.5 g, 3.6 mmol) and 4-fluoronitrobenzene (1.6 g, 1.0 mmol) were added to a solution of 3-hydroxy-5-methylpyrazole (0.33 g, 3.4 mmol) in DMF (50 ml) at room temperature, and further, the mixture was stirred at room temperature for 8 hours. After completion of the reaction, the reaction mixture was poured into 2N hydrochloric acid (100 ml) and extracted with ethyl acetate (30 ml×3). An organic layer was washed with water, dried over anhydrous magnesium sulfate and filtered to remove a desiccant, and the solvent was distilled off from the filtrate under reduced pressure. The resultant crude product was purified with a silica gel column (ethyl acetate/hexane=1/7→1/3), to give a white solid of 5-methyl-3-(4-nitrophenyloxy)pyrazole (0.4 g, yield: 63.3%) mp: 124-125° C.; 1H-NMR (CDCl3, TMS, ppm): δ 2.33 (s, 3H), 5.75 (s, 1H), 7.20 (dd, J=2.2 and 7.1 Hz, 2H), 8.22 (dd, J=2.2 and 7.1 Hz, 2H), 9.30-9.90 (br s, 1H).

1. customAfter completion of the reaction
2. extractionextracted with ethyl acetate (30 ml×3)
3. washAn organic layer was washed with water
4. dry with materialdried over anhydrous magnesium sulfate
5. filtrationfiltered
6. customto remove a desiccant, and the solvent
7. distillationwas distilled off from the filtrate under reduced pressure
8. customThe resultant crude product was purified with a silica gel column (ethyl acetate/hexane=1/7→1/3)