General procedure for the synthesis of 2-methyl-6-oxo-1,6-dihydro-[3,4'-bipyridyl]-5-carbonitrile from 2-methyl-6-oxo-1,6-dihydro-[3,4'-bipyridyl]-5-carboxamide: Concentrated sulfuric acid (350 μL, 6.3 mmol, 14 equiv) was added to 6-methyl-2-oxo-5-(pyridin-4-yl)-1,2- dihydropyridine-3-carbonitrile (95 mg, 0.450 mmol, 1 eq.) The reaction mixture was heated to 120 °C and maintained for 15 min. Upon completion of the reaction, the mixture was cooled to 0 °C, diluted with water, followed by slow addition of concentrated ammonium hydroxide solution to adjust the pH to 10. The precipitate was collected by filtration and washed with an appropriate amount of water, and dried to afford the target product, 2-methyl-6-oxo-1,6-dihydro-[3,4'-bipyridyl]-5-carboxamide, as a white solid (74 mg, 72% yield).
