1-Bromo-2-methylpropane → 1-Isobutyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

A mixture of 4-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (1 g, 5.15 mmol, 1.00 equiv), 1-bromo-2-methylpropane (1.05 g, 7.66 mmol, 1.49 equiv) and Cs2CO3 (3.36 g, 10.31 mmol, 2.00 equiv) in acetonitrile (60 mL) was stirred at 80° C. for 4 h. The reaction was cooled to room temperature and the solid material was removed by filtration. The filtrate was diluted with ethyl acetate (30 mL) and then washed with brine (40 mL). The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum to give 1.14 g (88%) of 1-iso-butyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole as a colorless oil. 1H-NMR (300 MHz, CDCl3): δ 7.78 (s, 1H), 7.65 (s, 1H), 3.91 (d, J=7.2 Hz, 2H), 2.24-2.19 (m, 1H), 1.32 (s, 12H), 0.90 (d, J=7.2 Hz, 6H) ppm. LCMS (method D, ESI): RT=1.51 min, m/z=251.0 [M+H]+.

Provenance & Evidence