1H-Pyrazole,3-methyl-5-phenyl- → 4-bromo-3-methyl-5-phenyl-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-methyl-3-phenyl-1H-pyrazole (8.0 g, 50.6 mmol) in dichloromethane (150 mL) was added bromine (8.08 g, 50.6 mmol) dropwise at 0° C. The reaction was stirred at 0° C. for 30 min and then at room temperature for 2 h before quenching with aqueous Na2SO3 (10% w/w, 10 mL). The organic solvent was removed and the aqueous phase was extracted with EtOAc, washed with brine, dried over MgSO4, and concentrated. The residue was purified by silica gel column chromatography to give the title compound as a yellow oil (9.5 g). LCMS m/z=236.9 [M+H]+; 1H NMR (400 MHz, DMSO-d6) δ ppm 2.26 (s, 3H), 7.30-7.57 (m, 5H), 13.12 (s, 1H).

Provenance & Evidence