Potassium Carbonate → HCID 66876696, compound

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A mixture of 3-(1,1-difluoroethyl)-1-phenyl-1H-pyrazol-5-amine (528 mg, 2.37 mmol), potassium carbonate (979 mg, 7.10 mmol) and phenyl chloroformate (556 mg, 3.55 mmol) in anhydrous dichloromethane (20 mL) was stirred at rt for 15 h. Additional phenyl chloroformate (556 mg, 3.55 mmol) and potassium carbonate (979 mg, 7.10 mmol) was added and the mixture stirred for a further 4 h. The mixture was concentrated under reduced pressure and the residue partitioned between ethyl acetate and saturated aqueous sodium hydrogen carbonate solution. The organic layer was separated, washed with water, saturated aqueous sodium hydrogen carbonate solution, then dried over magnesium sulfate and filtered. Concentration under reduced pressure gave an oil which was purified via silica gel column chromatography (eluting with a gradient of 12% ethyl acetate in hexanes to 100% ethyl acetate) to afford phenyl 3-(1,1-difluoroethyl)-1-phenyl-1H-pyrazol-5-ylcarbamate (400 mg, 49%) as an oil. 1H NMR (300 MHz, CDCl3) δ 7.51-7.58 (m, 5H), 7.35-7.41 (m, 2H), 7.26 (m, 1H), 7.15 (m, 2H), 7.00 (brs, 1H), 6.80 (s, 1H), 2.04 (t, J=18 Hz, 3H); LC-MS (ESI) m/z 344 (M+H)+.

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