Abstract
A simple synthetic strategy is described for synthesis of the hitherto unreported 6-arylhydrazono-1,3-diphenyl-7-methyl-1H-pyrazolo[3',4':4,5]pyrimido[1,6-b][1,2,4]triazepin-5(6H)-ones Sa-j. The acid dissociation constants were determined for the series prepared and were Correlated by the Hammett equation using the enhanced substituent constants. The results of such a correlation together with the spectral data indicated that the Studied compounds exist predominantly in the hydrazone tautomeric form. (c) 2008 Elsevier Ltd. All rights reserved.