Tetrazole derivatives XIX. Synthesis and properties of 1-(2-methyl-5-tetrazolyl)-3,5-diphenylformazan and a verdazyl radical

Benzaldehyde 2-methyl-5-tetrazolylhydrazone was synthesized and converted to a formazan, which undergoes methylation at the exocyclic nitrogen atom on reaction with dimethyl sulfate. The reaction product undergoes cyclization to the 1-(2-methyl-5-tetrazolyl)-3,5-diphenylleucoverdazyl radical when it is heated. Tautomerism due to location of the proton at the N(₂) or N₍₄₎ atom of the tetrazine ring is characteristic for the verdazyl radical, according to the PMR spectral data. A verdazyl radical was obtained by oxidation of the leucoverdazyl radical.See 1] for communication XVIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 991–995, July, 1978.