[N:1]1[CH:6]=[CH:5][CH:4]=[C:3]([C:7]2[C:8](=O)[NH:9][CH:10]=[CH:11][CH:12]=2)[CH:2]=1.[OH-].[Na+].P(Br)(Br)([Br:18])=O>>[Br:18][C:8]1[C:7]([C:3]2[CH:2]=[N:1][CH:6]=[CH:5][CH:4]=2)=[CH:12][CH:11]=[CH:10][N:9]=1A mixture of 0.30 g of 3-(3-pyridinyl)-2(1H)pyridinone and 10 ml of phosphorus oxybromide was heated on a steam bath for 18 hours, then poured onto crushed ice and made alkaline with 10N sodium hydroxide. The resulting solid was collected, dissolved in methylene chloride and the solution passed through a short pad of hydrous magnesium silicate. The filtrate was concentrated and while boiling diluted with hexane. Concentration and chilling gave 2'-bromo-3,3'-bipyridine as white crystals, mp 97°-98° C.
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