128143-88-4

149817-62-9

Example 5 Synthesis of 4'-bromo-2,2':6',2''-terpyridine (5): in a 500 mL flask was added 2,6-bis(2-pyridyl)-4(1H)-pyridinone (2.47 g, 9.9 mmol), phosphorus pentabromide (6.6 g, 15.4 mmol), and phosphorus tribromide oxide (30 g), and the mixture was heated to 100 °C and stirred for 12 hours The mixture was heated to 100 °C and stirred for 12 h. Upon completion of the reaction, a black oily residue was obtained. After cooling the reaction mixture to room temperature, ice water was carefully added. Subsequently, the reaction mixture was neutralized with aqueous K2CO3, extracted with dichloromethane (3 x 300 mL), the organic phase was dried with anhydrous magnesium sulfate, and the solvent was removed by filtration under reduced pressure to give a brown solid. The solid was purified by chromatography on a neutral alumina column using 2:1 dichloromethane/hexane as eluent, resulting in 2.65 g of pure 4'-bromo-2,2':6',2''-terpyridine in 86% yield (based on 2.47 g of 2,6-bis(2-pyridyl)-4(1H)-pyridinone feedstock).