Cesium carbonate → 2-methyl-1-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl]propan-2-ol

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Reaction Conditions

Reaction Steps

A suspension of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (514.3 mg, 2.65 mmol), cesium carbonate (1.295 g, 3.98 mmol) and 2,2-dimethyloxirane (0.589 mL, 6.63 mmol) in acetonitrile (5 mL) was heated at 130° C. under microwave for 1 h. The resulting mixture was concentrated. The residue was triturated with dichloromethane, stirred at room temperature for 30 min and filtered. The filtrate was concentrated to give crude 2-methyl-1-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl)propan-2-ol (0.4289 g). This material was used in subsequent Suzuki coupling reactions without further purification. 1H NMR (400 MHz, DMSO-d6) δ ppm 7.84 (d, J=0.4 Hz, 1H), 7.55 (d, J=0.7 Hz, 1H), 4.02 (s, 2H), 4.01 (s, 1H), 1.25 (s, 12H), 1.04 (s, 6H).

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