Iodoethane → 1-Ethyl-4-(4-fluoro-phenyl)-3-(4-methanesulfonyl-phenyl)-5-trifluoromethyl-1H-pyrazole

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Reaction Steps

4-(4-Fluorophenyl)-3-[4-(methylsulfonyl)phenyl]-5-(trifluoromethyl)-1H-pyrazole from step 3 (1.81 g, 4.3 mmol) and ethyl iodide (0.86 g, 5.5 mmol) were stirred vigorously in 20 mL dry dimethylformamide (DMF) with finely powdered potassium carbonate (0.58 g, 4.2 mmol) under nitrogen at 25° C. for 18 hours. The mixture was diluted with ethyl acetate and filtered to remove solids. The organic filtrate was washed with two portions of water followed by brine, dried over MgSO4 and concentrated in vacuo. The desired 1-ethyl-4-(4-fluorophenyl)-3-[4-(methylsulfonyl)phenyl]-5-(trifluoromethyl)-1H-pyrazole was isolated by chromatography on silica gel using ethyl acetate/toluene (10/90) as the eluant, giving 0.65 g (69%) of a white solid: mp 133-135.5° C.

Provenance & Evidence