Potassium Carbonate → 3-Ethynyl-5-(4-fluoro-phenyl)-1-methyl-1H-pyrazole

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Reaction Steps

To a solution of (1-diazo-2-oxo-propyl)-phosphonic acid dimethyl ester (2.27 g, 11.8 mmol) in methanol (100 mL) were added 5-(4-fluoro-phenyl)-1-methyl-1H-pyrazole-3-carbaldehyde (may be prepared in analogy to WO2005014553, 2.00 g, 9.8 mmol) and potassium carbonate (2.84 g, 20.56 mmol) and the resulting yellow suspension was stirred for 19 h at ambient temperature. After extraction with aqueous sodium hydrogencarbonate and ethyl acetate the combined organic layers were washed with brine, dried over sodium sulfate. Concentration and purification by chromatography (SiO2, hexane:ethyl acetate=100:0 to 75:25) afforded the title compound (1.83 g, 93%) as a white solid. MS: m/e=201.3 [M+H]+.

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