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

HRID 1907176Notes

Reaction equation

[Br:1]Br.[CH3:3][N:4]1[C:8]([C:9]2[CH:14]=[CH:13][C:12]([CH3:15])=[CH:11][CH:10]=2)=[C:7]([C:16](=[O:18])[CH3:17])[CH:6]=[N:5]1>C(O)(=O)C>[Br:1][CH2:17][C:16]([C:7]1[CH:6]=[N:5][N:4]([CH3:3])[C:8]=1[C:9]1[CH:14]=[CH:13][C:12]([CH3:15])=[CH:11][CH:10]=1)=[O:18]

Participants

Conditions

Temperature: 80 °C

Procedure

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).

Workup

customAfter removal of solvent under reduced pressure
additionthe residue was diluted with ethyl acetate
washwashed with saturated aqueous sodium bicarbonate solution
washwashed with saturated sodium chloride solution
dry with materialdried over sodium sulfate
filtrationFiltration and concentration of the filtrate in vacuo
customprovided a residue, which
customwas purified via silica gel chromatography (Gradient: 10% to 30% ethyl acetate in heptane)

Sources & evidence

ORD record: ord-7ac45c2370224c57a3c1f767164a799a
Source dataset: uspto-grants-2013_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08598155B2

Reaction notes

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