Abstract
A simple synthetic strategy is described for synthesis of 3-arylazo-2-methyl-7-phenylpyrimido[1,2- b][1,2,4]triazepine-4,9-diones 4a–j. The acid dissociation constants were determined for the series prepared and were correlated by a Hammett-type equation using enhanced substituent constants. The results of such correlation together with the spectral data, including
15
N isotopic labelling, indicated that the studied compounds exist predominantly in the hydrazone tautomeric form.