Synthesis of Benzazoles through Electrochemical Oxidative Cyclization Reactions

An effective method for the synthesis of benzazoles through the electrochemical oxidative cyclization ofo-aminophenol/o-aminothiophenol/o-phenylenediamine and aldehydes was developed. A series of benzazoles were efficiently synthesized by using this method in good yields. Furthermore, this method was applied to the synthesis of the drug thiabendazole in a gram-scale reaction, which proved the practicality of the method. This approach avoids using catalysts and oxidants, and has the advantages of wide substrate range, mild reaction conditions and good tolerance of functional groups. Finally, the possible reaction mechanism was proposed and supported by cyclic voltammetry (CV) and control experiments.