Bromine → 2-bromo-1-[1-methyl-5-(4-methylphenyl)-1H-pyrazol-4-yl]ethanone

Participants

Reaction Conditions

Reaction Steps

Bromine (97%, 0.104 mL, 1.97 mmol) was added to a solution of 1-[1-methyl-5-(4-methylphenyl)-1H-pyrazol-4-yl]ethanone (420 mg, 1.96 mmol) in glacial acetic acid (10 mL), and the reaction mixture was vigorously stirred for 2 hours at 80° C. After removal of solvent under reduced pressure, the residue was diluted with ethyl acetate, washed with saturated aqueous sodium bicarbonate solution, washed with saturated sodium chloride solution and dried over sodium sulfate. Filtration and concentration of the filtrate in vacuo provided a residue, which was purified via silica gel chromatography (Gradient: 10% to 30% ethyl acetate in heptane) to afford the product as a colorless oil. Yield: 353 mg, 1.20 mmol, 61%. LCMS m/z 293.1 (M+1). 1H NMR (400 MHz, CDCl3) δ 2.46 (s, 3H), 3.71 (s, 3H), 3.97 (s, 2H), 7.31 (br AB quartet, JAB=8 Hz, ΔvAB=23 Hz, 4H), 8.05 (s, 1H).

Provenance & Evidence