Pyrazole → 1-(3-Bromophenyl)-1H-pyrazole

Participants

Reaction Steps

To a suspension of sodium hydride (3.52 g, 88 mmol) in DMF (40 ml), was added pyrazole (3.0 g, 44 mmol) in portions. After stirring at room temperature for 30 minutes, 1-bromo-3-fluorobenzene (9.3 g, 53 mmol) in DMF (20 ml) was added dropwise and the resulting mixture was stirred for 2 hours at 130° C. The mixture was cooled and quenched by the addition of a saturated aqueous NH4Cl solution and extracted with ethyl acetate. The organic layer was washed with brine, dried over Na2SO4 and concentrated under reduced pressure. The residue was purified using normal phase chromatography, eluting with petroleum ether containing 10% ethyl acetate to give 1-(3-bromophenyl)-1H-pyrazole (4.7 g) as yellow solid.

Provenance & Evidence