Bromine → 4-Bromo-1-cyclopropyl-1H-pyrazole

Participants

Reaction Steps

To a solution of crude 1-cyclopropyl-1H-pyrazole (108 mg, 1.00 mmol) in CHCl3 (4 mL) at room temperature was added Br2 (51 uL, 1.0 mmol) via syringe. The orange solution was stirred for 1 h. The reaction was diluted with saturated aqueous Na2S2O3 (3 mL) and saturated aqueous NaHCO3 (3 mL). The mixture was extracted with CH2Cl2 (3×5 mL). The combined organic layers were dried over Na2SO4 and concentrated on a rotary evaporator without heating the sample to give 4-bromo-1-cyclopropyl-1H-pyrazole as a volatile, light yellow liquid that was used without further purification, m/z 187.3 [M+H]+.

Provenance & Evidence