Tetrazole derivatives

A series of 5-aryl-3-phenyl-1-(tetrazol-5-yl)formazans has been obtained by the azo coupling reaction. In an aqueous alkaline medium they are oxidized to tetrazolium salts with a betaine structure. Information is given on the electronic spectra of the formazans and the tetrazolium salts and the acidic properties and complex-forming capacity of the formazans.For Communication VII, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1570–1573, November 1973.