Synthesis and electrochemical oxidation of derivatives of 1,4-dihydro-1,2,4,5-tetrazine

1.Oxidation of the arylhydrazones of the acetylhalides by PbO₂ leads to the formation of 1,3,4,6-tetraaryl-1,4-dihydro-1,2,4,5-tetrazines, which, in turn, form stable cation-radicals under electrochemical oxidation.2.The stability of the dihydrotetrazine cation-radicals can be reduced, either by replacing the phenyl group at the nitrogen atom with a tosyl group or a hydrogen atom, or by replacing the phenyl groups at the carbon atoms with acetyl groups.3.Substituents at the amine N atom are more influential than substituents at the C atoms in fixing the first wave potential for the electrochemical oxidation of 1,4-dihydro-1,2,4,5-tetrazine.