Cesium carbonate → 1-(2-Methoxyethyl)-1H-pyrazole-4-boronic acid, pinacol ester

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Reaction Steps

A mixture of [A] 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (100 mg, 0.5 mmol), 2-bromoethyl methyl ether (58 uL, 0.62 mmol, Aldrich, Cat. No. 238155), and cesium carbonate (500.0 mg, 1.5 mmol) in acetonitrile (1 mL) was stirred at 90° C. overnight. After cooling it was quenched with water, extracted with ethyl acetate. The extract was washed with water twice, brine once; dried over Na2SO4. After filtration the filtrate was concentrated to yield 90 mg of the product. LCMS (M+H)+: m/z=253.1

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