[CH2:1]([C:3]1[NH:7][N:6]=[C:5]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=2)[CH:4]=1)[CH3:2].[Br:14]Br>C(Cl)Cl>[Br:14][C:4]1[C:5]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=2)=[N:6][NH:7][C:3]=1[CH2:1][CH3:2]To a solution of 5-ethyl-3-phenyl-1H-pyrazole (10.0 g, 58.1 mmol) in DCM (150 mL) was added dropwise bromine (9.28 g, 58.1 mmol) at 0° C. The reaction was stirred at that temperature for 30 min and continued for 2 h at room temperature before quenched with aqueous Na2SO3 solution (10% wt, 10 mL). DCM was removed and the residue 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 liquid (9.5 g). LCMS m/z=250.9 [M+H]+; 1H NMR (400 MHz, DMSO-d6) δ ppm 1.22 (t, J=7.58 Hz, 3H), 2.66 (q, J=7.58 Hz, 2H), 7.40-7.56 (m, 3H), 7.82 (d, J=7.58 Hz, 2H), 13.15 (s, 1H).
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