Abstract
A simple synthetic strategy is described for synthesis of the hitherto unreported 5-arylazo-1,3-diphenyl-6-substituted-1H-pyrazolo[3,4-d]pyrimido[1,6-b][1,2,4]triazines 5a-n. The spectral data indicated that the studied compounds exist predominantly in the hydrazone tautomeric form 5A. The site-selectivity and mechanism of the studied reactions are discussed.