Electrochemical Synthesis of 1,2,4-Thiadiazoles through Intermolecular Dehydrogenative S-N Coupling

An electrochemical intermolecular dehydrogenative coupling reaction of isothiocyanates with 2-aminopyridines/amidines was developed. Using n-Bu4NI as the catalyst and electrolyte, 1,2,4-thiadiazoles and pyrido-fused 1,2,4-thiadiazoles were readily accessed with good to excellent efficiency under the undivided electrolysis conditions. This electrochemical approach obviates the use of external oxidants and transition-metal catalysts.