877149-80-9

The reaction mixture was suspended in acetonitrile (30 mL) in the presence of cesium carbonate (6.72 g, 20.61 mmol) using 4-pyrazolylboronic acid pinacol ester (2 g, 10.31 mmol) and dimethylaminoethyl chloride hydrochloride (2.227 g, 15.46 mmol). The mixture was heated to reflux for 5 hours and then cooled to room temperature. The reaction solution was diluted with ether and filtered, and the filtrate was concentrated in vacuum to afford N,N-dimethyl-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl)ethanamine (2.61 g, 9.84 mmol, 95% yield) as an amber colored oil, which was used directly in the next step of the reaction.

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