The general procedure for the synthesis of 6-bromo-2,3'-bipyridine from the compound (CAS: 220565-63-9) and 2,6-dibromopyridine was as follows: to a 25 mL round-bottomed flask under argon protection was added Pd(PPh3)2Cl2 (0.06 g, 2.0 mol%), 2,6-dibromopyridine (0.60 g, 2.5 mmol), and 5.0 mL of a THF solution of 4-(ethoxycarbonyl)phenyl zinc bromide (0.5 M, 2.5 mmol). The reaction mixture was stirred for 0.5 h at room temperature. Upon completion of the reaction, the reaction was quenched with saturated NH4Cl solution and subsequently extracted with ether (10 mL x 3). The organic phase was washed sequentially with saturated NaHCO3 solution, Na2S2O3 solution and brine and dried over anhydrous MgSO4. Purification by silica gel column chromatography (eluent: 10% ethyl acetate/90% heptane) afforded 0.31 g of the target product, 6-bromo-2,3'-bipyridine (3a), in 50% isolated yield as a white solid.
