Synthesis of functionalised bipyridines by sequential nucleophilic substitution of hydrogen and cycloaddition in 1,2,4-triazine rings

A new methodology for the synthesis of functionalised bipyridines by the direct cyanation of 3-(2-pyridyl)-1,2,4-triazine 4-oxide through nucleophilic substitution for hydrogen followed by the transformation of the 1,2,4-triazine ring into the pyridine ring by the Diels–Alder reaction and, finally, the chemical conversion of the cyano group is described.