Synthesis and tautomeric structure of 3,6-bis(arylazo)pyrazolo[1,5-a]pyrimidine-5,7(4H,6H)-diones

摘要

Two series of 3,6-bis(arylazo)pyrazolo[1,5-a]pyrimidine-5,7-diones were prepared, and their acid dissociation constant pK_as were determined and correlated with the Hammett equation. The results of these correlations,together with the spectroscopic data, indicated that the title compounds exist predominantly in the 3-arylazo-6- arylhydrazonopyrazolo[1,5-a]pyrimidine-5,7-dione tautomeric form, both in the solid and solution phases.