Mechanistic investigation of N-thioamidoimidates: Oxidation by heterogeneous and homogeneous electron transfers

摘要

Electrochemical study of N-thioamidoimidates 1 is carried out in non-aqueous solvent at platinum electrodes by means of cyclic voltammetry at different scan rates. A mechanistic investigation shows that the oxidation of the NH bond of these substrates leads, during macroscale electrolysis, to oxadiazole-3-thione 2 with satisfactory yields according to an ECE mechanism. On the other hand, the rate of deprotonation K{sub}H and the standard oxidation potential of the N-thioamidoimidate cation radical/N-thioamidoimidate couple were derived directly and indirectly by the use of the homogenous redox catalysis. The perfect agreement of the predicted kinetic with the experiment data both under homogeneous and heterogeneous electron transfer provides further support for the ECE mechanism.