Synthesis
General procedure for the synthesis of 6-bromo-2,2'-bipyridine from 2,6-dibromopyridine and 2-tributylmethylstannylpyridine: 1.5 g (6.33 mmol) of 2,6-dibromopyridine, 3.48 g (9.48 mmol) of 2-tributylmethylstannylpyridine and 0.15 g (0.06 mmol) of tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) were were dissolved in 15 mL of toluene in a two-necked round bottom flask. The reaction mixture was stirred at 80°C for about 24 hours. Upon completion of the reaction, the solvent was removed by evaporation under reduced pressure. The resulting residue was dissolved in dichloromethane and subsequently extracted with 6M hydrochloric acid solution. The aqueous layer was separated and collected, the pH was adjusted by adding ammonia to the aqueous layer and extracted with dichloromethane. The organic layer was separated and dried with anhydrous magnesium sulfate (MgSO4) followed by evaporation under reduced pressure to remove the solvent. Purification by column chromatography (eluent: hexane/ethyl acetate=5:1, v/v) afforded 0.9 g of 6-bromo-2,2'-bipyridine as a white solid (yield: 61%).
References
[1] Organic Letters, 2008, vol. 10, # 6, p. 1091 - 1094
[2] Chemical Communications, 2007, # 42, p. 4401 - 4403
[3] Organometallics, 2017, vol. 36, # 9, p. 1727 - 1735
[4] Patent: KR2015/142709, 2015, A. Location in patent: Paragraph 0473-0475
[5] Inorganic Chemistry, 2013, vol. 52, # 9, p. 5570 - 5580
