4-Bromopyrazole → 4-Bromo-1-cyclobutylpyrazole

Participants

Reaction Steps

To a cooled (0 C) stirred solution of 4-bromo-1H-pyrazole (5.360 g, 36.47 mmol) in DMF (50 mL) was added sodium hydride (1.925 g, 80.23 mmol) slowly. The mixture was allowed to stir in the ice bath 30 min and bromocyclobutane (3.433 ml, 36.47 mmol) was added. The vessel was sealed and the reaction mixture heated at 95 C for 23 h. The mixture was allowed to cool to rt and diluted with 200 mL EtOAc, washed with 500 mL water, then 2×100 mL water, sat NaHCO3, then the organic layer dried over Na2SO4, filtered and evaporated. The mixture was purified via flash chromatography using a CH2Cl2 in hexanes gradient. (I2 stain for visualization). The title compound was collected as a colorless liquid.

Provenance & Evidence