Electrocataiytic Selective Oxidation Of Thioamides To Synthesis Of Heterocyclic Sulfur Compounds

Sulfur containing heterocyclic compounds exist widely in nature,such as penicillin,isoniazid and other typical drugs,and herbicides such as chlorpyrifos and buprofezin are widely used in medicine and pesticide fields.Therefore,the synthesis of sulfur-containing heterocyclic compounds is still the hot topic up to now.In recent years,organic electrochemical synthesis,as a combination of organic chemistry and electrochemical technology,has developed rapidly.Compared with traditional organic synthesis,organic electrochemical synthesis has the advantages of precise control of the selectivity and process of chemical reaction.Therefore,it is necessary to develop electrochemical synthesis.In this paper,three sulfur-containing heterocyclic compounds were synthesized from ?-aroylthioamides(KTAs)at room temperature without any metal or oxidant.Dihydrothiophene products were obtained when the reaction system was in constant current 2.0 m A and acetonitrile as solvent;thiazoline products were obtained when the reaction system was in constant current 1.0 m A and ethanol as solvent;dithioin products were obtained when the reaction system was in constant current 2.0 m A and the group connected with amide was aliphatic and acetonitrile as solvent.The system can react in air at room temperature.It has the advantages of high chemical selectivity,no metal,no oxidant,mild electrolysis conditions,simple operation,and can be amplified.Moreover,the reaction has a wide range of functional groups.Through cyclic voltammetry experiment,density functional theory,control experiment and our group's research on thioamides,we first proposed the mechanism of sulfur free radical and carbon free radical tautomerism of thioamides.The structures of all target compounds were characterized by spectrogram,and the structure of compound 2a was determined by single crystal X-ray diffraction.