Electrocyclization of Semicarbazone; A Novel Route of Green Synthesis of 2,5-Disubstituted-1,3,4-Oxadiazoles

The anodic oxidation of a number of arylsemicarbazides derivatives (I) has been examined in acetonitril containing lithium perchlorate (LiClO4) as a supporting electrolyte (20g/l). The reaction was sensitive to the amount of electricity passed through the cell, so the electrode potential was determined on the basis of the oxidation potential of the compound which is measured by using the cyclic voltammetry. The electrochemistry reaction has been realised under controlled- potential because the constant current condition is necessary to carry the reaction in high selectivity. In this reaction condition the anodic oxidation of arylsemicarbazides derivatives (I) gives 2,5-disubstituted1,3,4-oxadiazoles (II) as final compound.