The general procedure for the synthesis of 3,5-dimethyl-2,6-dibromopyridine from 3,5-dimethylpyridine was as follows: bromine (Br2, 5.64 mL, 110 mmol) was added dropwise to a fuming sulfuric acid solution (40 mL) of 3,5-dimethylpyridine (5.35 g, 50 mmol) under stirring at 177 K. The reaction was carried out in the following manner. The temperature was maintained and stirring of the reaction mixture was continued for 30 minutes. Subsequently, the reaction system was slowly warmed to 353 K and refluxed at this temperature for 36 hours. Upon completion of the reaction, the solution was cooled to room temperature and slowly poured into water. The reaction mixture was neutralized with aqueous sodium hydroxide (NaOH). The crude product was isolated by filtration. The crude product was purified by column chromatography (eluent: dichloromethane) to yield 3,5-dimethyl-2,6-dibromopyridine (10.71 g, 80% yield) as a white solid with a melting point of 102-103 °C. The product was purified by column chromatography. The structure of the product was confirmed by the following characterization data: 1H NMR (400 MHz, CDCl3): δ 7.35 (s, 1H, pyridinium-H), 2.30 (s, 6H, -CH3); 13C NMR (100 MHz, CDCl3): δ 141.11, 139.51, 134.21, 20.96; IR (KBr, ν, cm- 1): 3132, 1585, 1535, 1386, 1082, 974, 705.
