N,N-diethyl-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl)ethanamine

269410-08-4

5392-81-4

1086111-20-7

A solution was prepared in tetrahydrofuran at 0°C using 4-pyrazoleboronic acid pinacol ester (250 mg, 1.29 mmol) and sodium hydride (61.8 mg, 2.58 mmol) as starting materials. Subsequently, 2-bromo-N,N-diethylethylamine (558 mg, 2.58 mmol) was added to the solution. The reaction system was slowly warmed up to room temperature and the progress of the reaction was monitored by LCMS.After 90 min, if the reaction did not take place, potassium iodide (1.71 g, 10.3 mmol) was added and the reaction mixture was heated at 50 °C overnight. After completion of the reaction, the reaction mixture was diluted with a large amount of ethyl acetate and water and liquid-liquid partitioning was performed. The organic layer containing the target product was collected, washed with brine and concentrated by vacuum to give a clear thick oily product. It was analyzed by LCMS and confirmed to be pure N,N-diethyl-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl)ethylamine (340 mg, 90% yield, M + 1 294.2).