Various conditions for the inverse electron-demand aza-Diels-Alder reaction in the series of 5-aryl-3-(2-pyridyl)-1,2,4-triazine-5-carbonitriles and 2-amino-4-aryloxazoles to obtain 4,5-diaryl-3-hydroxy-2,2'-bipyridine-6-carbonitriles were studied. Heating in 1,2-dichlorobenzene and solvent-free conditions were found to be the most effective.