To a 250 mL round bottom flask under nitrogen protection was added 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (2.00 g, 9.61 mmol), 1,4-dibromobenzene (2.30 g, 9.75 mmol), tetrakis(triphenylphosphine)palladium (550 mg, 0.48 mmol), potassium carbonate (2.60 g, 18.8 mmol), 1,4-dioxane (40 mL) and water (10 mL). The reaction mixture was stirred at 80 °C for 3 hours. After completion of the reaction, the mixture was concentrated to dryness. The residue was purified by silica gel column chromatography with ethyl acetate/petroleum ether (1/10, v/v) as eluent to give 4-(4-bromophenyl)-1-methyl-1H-pyrazole (1.70 g, 75% yield) as a yellow solid.
