Electrochemical synthesis of 1,2,4-triazol-3-thione derivatives: Anodic oxidation of N-thioamidohydrazones

The electrochemical oxidation of N-thioamidohydrazone, 1, was undertaken at platinum electrode in acetonitrile containing lithium perchlorate as supporting electrolyte and monitored via cyclic voltammetry and controlled potential coulometry. An overall process consisting of an irreversible two electron transfer involving, in absence or presence of a base, deprotonation and intramolecular cyclization reactions enables the formation of 1,2,4-triazol-3-thione in a satisfactory yield.