反应详情

温度

70 °C

Potassium carbonate (1.66 g, 12 mmol) was added to a solution of 3-hydroxy-5-methylpyrazole (2.45 g, 25.0 mmol) and 3-chloro-4,5-difluorobenzotrifluoride (2.5 g, 25.0 mmol) in DMF (40 ml), and the mixture was stirred under heating at 70° C. for 4 hours. After completion of the reaction, the reaction mixture was poured into 2N hydrochloric acid (100 ml) and extracted with ethyl acetate (50 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=1/5), to give a white solid of 3-(2-chloro-6-fluoro-4-trifluoromethylphenyloxy)-5-methylpyrazole (2.29 g, yield: 33.8%). mp: 171-174° C.; 1H-NMR (CDCl3, TMS, ppm): δ 2.27 (s, 3H), 5.71 (s, 1H), 7.37 (dd, JHF=1.8 and 9.4 Hz, 1H), 7.54 (s, 1H), 8.85-9.55 (br s, 1H).

1. customAfter completion of the reaction
2. extractionextracted with ethyl acetate (50 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=1/5)