Potassium Carbonate → 1-(3-(Benzyloxy)propyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

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Reaction Conditions

Reaction Steps

A mixture of 4-(4,4,5,5-tetramethyl[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (5.0 g, 26 mmol), potassium carbonate (4.27 g, 30.9 mmol) and 1-bromo-3-benzyloxypropane (6.20 g, 27.0 mmol) in DMF (20 mL) was stirred at 80° C. overnight, quenched with water (20 mL) and extracted with EtOAc (100 mL). The organic layer was washed with water (2×30 mL), brine (30 mL), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by silica gel chromatography (ISCO system: EtOAc/Heptane=30-70%) to afford 7.67 g of the title compound as a light-yellow oil (87%). 1H NMR (CDCl3, 400 MHz): δ=7.80 (s, 1H), 7.66 (s, 1H), 7.30-7.36 (m, 5H), 4.48 (s, 2H), 4.28 (t, J=6.8 Hz, 2H), 3.43 (t, J=5.8 Hz, 2H), 2.17 (m, 2H), 1.33 (s, 12H). MS (ES+): m/z=343.36 [MH+]. HPLC: tR=4.20 min (ZQ3: polar—5 min).

Provenance & Evidence