反应详情

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 that temperature for 30 min and continued at room temperature for 2 h. After quenched with aqueous solution of Na2SO3 (10% wt aq., 10 mL), the organic solvent was removed and the aqueous mixture 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 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).

1. waitcontinued at room temperature for 2 h
2. customAfter quenched with aqueous solution of Na2SO3 (10% wt aq., 10 mL)
3. customthe organic solvent was removed
4. extractionthe aqueous mixture was extracted with EtOAc
5. washwashed with brine
6. dry with materialdried over MgSO4
7. concentrationconcentrated
8. customThe residue was purified by silica gel column chromatography