6813-38-3

1134-35-6

6813-38-3

General procedure for the synthesis of 2,2'-bipyridine-4,4'-dicarboxylic acid from 4,4'-dimethyl-2,2'-bipyridine: 1.0 g (5.4 mmol) of 4,4'-dimethyl-2,2'-bipyridine was added to a reaction flask, and 18 mL of concentrated sulfuric acid was added slowly dropwise with stirring. This process was accompanied by a large amount of exothermic heat, and after the solution was cooled to room temperature, 3.3 g (11.3 mmol) of potassium dichromate was added, and the solution then changed to a dark green color. Subsequently, the reaction mixture was stirred at 65°C for 6 hours. Upon completion of the reaction, it was cooled to room temperature and the reaction was poured into 1000 mL of water, which immediately produced a large white flocculent precipitate. The precipitate was collected by filtration and washed sequentially with water and methanol until the filtrate was clarified. Finally, the resulting white solid was dried under vacuum at 60 °C for 18 h to obtain the target product in 98% yield.