[C:1]([C:5]1[CH:10]=[CH:9][CH:8]=[C:7]([C:11]([CH3:14])([CH3:13])[CH3:12])[CH:6]=1)([CH3:4])([CH3:3])[CH3:2].[Br:15]Br>C(O)(=O)C.[N+]([O-])([O-])=O.[Ag+]>[CH3:12][C:11]([C:7]1[CH:6]=[C:5]([C:1]([CH3:4])([CH3:3])[CH3:2])[CH:10]=[CH:9][C:8]=1[Br:15])([CH3:14])[CH3:13]To a solution of 5.00 g (26.3 mmoles) of 1,3-di-t-butylbenzene in 15 ml of acetic acid was added 4.47 g (26.3 mmoles) of silver nitrate. The mixture was stirred in an oil bath at 75°-80° and then bromine (4.21 g, 26.3 mmoles) was added in small portions over 2 hours. After the addition was complete, the reaction mixture was stirred for a further 45 minutes. After cooling, the precipitated silver bromide was filtered off and washed with acetic acid. The combined filtrates were partitioned between dichloromethane and water and the aqueous layer was further extracted with dichloromethane. The combined organic extracts were washed with aqueous sodium bisulfite, dried over sodium sulfate, filtered, and evaporated. Acetic acid was then removed by azeotropic distillation with heptane. Distillation of the residue under reduced pressure gave 7.07 g of the title compound, b.p. 82°-84° C. (1 mm). The structural assignment was supported by 1H NMR and 13C NMR.
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