[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([NH:9][C:10](=[O:12])[CH3:11])=[C:5]([CH3:13])[CH:4]=1.[Br:14]Br.OS([O-])=O.[Na+].O>C(O)(=O)C.C(Cl)Cl>[Br:14][C:8]1[C:3]([O:2][CH3:1])=[CH:4][C:5]([CH3:13])=[C:6]([NH:9][C:10](=[O:12])[CH3:11])[CH:7]=1To a solution of N-(4-methoxy-2-methylphenyl)acetamide (130 g, 0.73 mol) in acetic acid (800 mL) is added bromine (42 mL, 0.8 mol) dropwise at 0° C. After addition, the resulting mixture is stirred at RT overnight. Saturated aqueous NaHSO3 is added until a clear solution is obtained, and then a large amount of water (2.0 L) is added forming a precipitate. The precipitated solid is collected and washed with water to give the crude product (thin layer chromatography (TLC) solvent: DCM:EtOAc=10:1). The solid is dissolved in minimum amount of refluxing DCM, and then PE (about 10-20% volume of DCM used) is added. The resulting solution is cooled to RT. After 2 hours, the precipitated solid is collected and washed with PE to give a white product (108 g, 57% yield). MS (m/z): 260.0 (M+H).
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