Hydrochloric Acid → Ethyl 3-(2-chloro-6-fluoro-4-trifluoromethylphenyloxy)-5-methylpyrazole-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a DMSO (15 mL) solution of ethyl 3-hydroxy-5-methylpyrazole-1-carboxylate (1.36 g, 8.0 mmol) and potassium carbonate (1.1 g, 8.0 mmol) was added 3-chloro-4,5-difluorobenzotrifluoride (1.77 g, 8.0 mmol) and the mixture was stirred under heating at 40° C. for 8 hours. After completion of the reaction, the reaction mixture was poured into 2 mol/L hydrochloric acid (30 mL) and extracted with ethyl acetate. The organic layers combined were washed with water, and dried over anhydrous magnesium sulfate, and the solvent was distilled off. The thus-obtained residue was purified by silica gel column chromatography (ethyl acetate:hexane=1:7˜1:5) to give a white solid of ethyl 3-(2-chloro-6-fluoro-4-trifluoromethylphenyloxy)-5-methylpyrazole-1-carboxylate (2.14 g, yield: 72.9%). Melting point: 127˜129° C., 1H-NMR (CDCl3, TMS, ppm): δ1.40 (t, J=7.1 Hz, 3H), 2.53 (d, J=0.8 Hz, 3H), 4.41 (q, J=7.1 Hz, 2H), 5.81 (d, J=0.8 Hz, 1H), 7.38 (dd, J=2.1 Hz, JHF=9.5 Hz, 1H), 7.50˜7.60 (m, 1H).

Provenance & Evidence