On Water Synthesis of 3-Aryl-1,2,4-triazolo[4,3-a]pyridines Using Iodobenzene Diacetate (IBD)

An iodobenzene diacetate (IBD)-mediated simple and green method was determined for the intramolecular oxidative cyclization of 3-aryl-2-pyridiylhydrazones of different aromatic aldehydes in an aqueous medium at room temperature. This efficient strategy provides a route to the synthesis of 3-aryl-1,2,4-triazolo[4,3-a]pyridines in water which eliminates the requirement to use costly and unsafe volatile organic solvents. All reactions were carried out by just stirring the reaction components in water at room temperature. This protocol provides a wide substrate scope and good functional group tolerance.