Nitro-substituted 2-aryl-[1,2,4]triazolo[1,5-a]azines in the reactions with C-nucleophiles

Synthesis of nitro-substituted [1,2,4]triazolo[1,5-a]pyrimidines based on oxidative cyclization of the corresponding nitropyrimidinyl hydrazones of aromatic aldehydes was developed. The reactions of 2-aryl-6-nitro-[1,2,4]triazolo[1,5-a]pyrimidines and their structural analogs (2-aryl-6,8-dinitro-[1,2,4]triazolo[1,5-a]pyridines) with different C-nucleophiles were studied. Nucleophilic addition to the pyridine and pyrimidine rings carried out under mild base-free conditions gave new stable 1.5-dihydro-[1,2,4]triazolo [1,5-a]-pyridines and 1.5-dihydro-[1,2,4]triazolo[1,5-a]pyrimidines in the yields up to 94%.