99970-84-0

General procedure for the synthesis of 2,2'-bipyridine-4,4'-dialdehyde from 4,4'-dimethyl-2,2'-bipyridine: To a 100 mL two-necked round-bottomed flask was added 4,4'-dimethyl-2,2'-bipyridine (500 mg, 0.00271 mol, 1.0 eq.) 100 mL of 1,4-dioxane was added drop-wise with stirring until complete solubilization. Subsequently, the system was bubbled with nitrogen for 15 minutes to remove oxygen from the system. Selenium dioxide (0.663 mg, 2.2 eq.) was added under nitrogen protection and reacted under reflux conditions for 44 hours. The reaction process was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the reaction mixture was washed 2 to 3 times with warm 1,4-dioxane, filtered, and 1,4-dioxane was evaporated under reduced pressure. The residue was dissolved in hot distilled ethyl acetate, filtered and washed with hot ethyl acetate. The ethyl acetate layer was washed with 1 M sodium carbonate solution (250 mL) to remove residual carboxylic acid. The organic layer was dried with anhydrous sodium sulfate, concentrated, and the residue was purified by alumina column chromatography with the eluent being a 60% petroleum ether solution of ethyl acetate to give the target product 2,2'-bipyridine-4,4'-dialdehyde. The products were characterized by infrared spectroscopy (IR), nuclear magnetic resonance hydrogen spectroscopy (1H NMR), nuclear magnetic resonance carbon spectroscopy (13C NMR) and high resolution mass spectrometry (HRMS).

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