[C:1]([O:13][CH3:14])(=[O:12])[C:2]1[CH:11]=[CH:10][CH:9]=[C:4]([C:5]([O:7][CH3:8])=[O:6])[CH:3]=1.BrBr.[Br:17](F)(F)F>>[Br:17][C:10]1[CH:9]=[C:4]([C:5]([O:7][CH3:8])=[O:6])[CH:3]=[C:2]([CH:11]=1)[C:1]([O:13][CH3:14])=[O:12]Conventionally, it is known that selective bromination of aromatic compounds having an electron-attracting group is very difficult. As techniques related to such a reaction, it is known, for example as a method for preparing dialkyl 5-bromoisophtalate a method comprising brominating dimethyl isophthalate with bromine at the presence of bromine trifluoride (BrF3) to give dimethyl 5-bromoisophtalate in a 55% yield (J. Org. Chem., 58, 239 (1993)). This method, however, uses bromine trifluoride that is expensive and intractable, and leads an aimed product in a low yield. Therefore, the above-mentioned method is not practical.
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