In a dry reaction flask, 4-bromopyridine (1.0 mmol), palladium acetate (5.61 mg, 0.025 mmol), indium (57.4 mg, 0.5 mmol), and lithium chloride (63.5 mg, 1.5 mmol) were dissolved in dry N,N-dimethylformamide (2 mL), and the mixture was reacted at 100 °C for 2.5 h under nitrogen protection. After the reaction was complete, the reaction mixture was quenched with saturated sodium bicarbonate aqueous solution, and the aqueous layer was extracted three times with ethyl acetate (3 × 20 mL). The organic layer was separated and washed with 20 mL of water and 20 mL of brine, respectively. The organic phase was dried with anhydrous magnesium sulfate, filtered to remove the drying agent, and the resulting filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate-n-hexane = 1:2) to obtain the target molecule 4,4'-bipyridine.
Figure 4,4'-bipyridine
