| Abstract: | The structure and tautomerism of 5-amino-4-arylazopyrazoles (2a-f) are investigated in aqueous media. In solutions of pH>5 these compounds exist as ring N—1 protonated species. At pH>10 they afford anions which are stabilized by delocalization of the negative charge in the ring as well as on the arylazo moiety. Controlled potential electrolysis and polarographic analysis indicate that 2a-f are reduced via a four electron reduction process to triaminopyrazole and the corresponding substituted aniline derivative. A mechanism is suggested and discussed. |
