Synthesis of 5-substituted tetrazoles based on the disodium salt of azotetrazole. investigation of the azotetrazole-2-(tetrazolyl-5)-6-imino-1,2,3,4-pentazine mesoion tautomerism

For the example of a salt of azotetrazole, for the first time we have investigated the azotetrazole-1,2,3,4,5-pentazine tautomerism. Upon treatment of an excess of the disodium salt of azotetrazole with dilute sulfuric acid, we isolated 5-substituted tetrazole, which on the basis of analysis data (with introduction of the ¹⁵N isotope into the compound) and study of the chemical properties with sufficiently high probability of assigning the structure of the first representative of the previously unknown class of compounds of the pentazine mesoion: the tetrahydrate of the sodium salt of the 2-(tetrazolyl-5)-6-imino-1,2,3,4,5-pentazine mesoion. We synthesized the dehydrate of the sodium and silver salts of 5-azodiazomethanotetrazole; using derivatography, we have studied the properties of the isolated compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 468–475, April, 1993.