Electrochemical Oxidative C3-functionalization Of Imidazo[1,2-a] Pyridine Derivatives

Since the advent of electrochemistry,Electrochemical organic synthesis has attracted increasing attention of scholars.Especially in the past decade,Scholars at home and abroad have made great efforts in the field of electrochemical organic synthesis and have also made considerable progress.In general,electrochemistry is considered as a powerful tool in the field of organic synthesis.Electrochemical organic synthesis represents a green and advantageous alternative to traditional organic synthetic methods.Among lots of nitrogen fused heterocyclic compounds,Imidazo[1,2-a]pyridine derivatives are widely used in the fields of optics,material science,medicinal chemistry and organometallics,so imidazo [1,2-a] pyridine scaffolds are regarded as an important structural unit.The functionalized imidazo[1,2-a]pyridines,especially those functionalized at the C3 position of imidazole ring,possess a variety of pharmacological activities such as antiviral,cytotoxic,antibacterial,fungicidal and antiinflammatory activities.This paper describes the advantages of electrochemical synthesis,the research progress of the functionalization of imidazo [1,2-a] pyridine derivatives at C3 position,the electrochemical oxidative halogenation and the electrochemical oxidative esterification of imidazo [1,2-a] pyridine derivatives at C3 position,the main research results are as follows:1.A green,efficient and environmentally friendly strategy of electrochemical oxidative C3 halogenation of imidazo [1,2-a] pyridine derivative was developed.Under mild electrochemical conditions,without exogenous oxidants and transition metal catalysts,combining anodic oxidation and cathodic reduction together to enable the C-H at C3 position of imidazo [1,2-a] pyridine derivatives to halogenation,and synthesis a series of important organic halides.2.A green,efficient and environmentally friendly strategy of electrochemical oxidative C3 esterification of imidazo [1,2-a] pyridine derivative was developed.Under mild electrochemical conditions,without exogenous oxidants and transition metal catalysts,the esterification of the C-H at C3 position position of imidazo [1,2-a] pyridine derivatives was achieved for the first time,and a series of important aryl esters were synthesized.