Electrochemical Dehydrogenation To Synthesize Imidazo[1,2-a]pyridine C-3 Cyano And Thiocyano Substituted Derivatives

Imidazo[1,2-a]pyridines can be functionalized at multiple sites,and these heterocyclic compounds exhibit a wide variety of pharmacological activities.At present,some progress has been made in the synthesis and modification of this heterocyclic ring.Organic electrochemical synthesis usually does not require the use of toxic or dangerous oxidants and reducing agents,which is a kind of green economy synthesis technology.Generally,the reaction system does not contain other reaction reagents(or add a small amount of electric catalyst),less byproducts,in addition to raw materials and products.In recent years,this catalytic method has attracted much attention from organic chemists.In this paper,based on organic electrochemical method,imidazolo[1,2-a]pyridines and its derivatives were modified with functional groups.The thesis mainly includes the following two aspects:1.Electrochemical Oxidative C-H Thiocyanation or Selenocyanation of Imidazopyridines and ArenesRegioselective C–H thiocyanation or selenocyanation of imidazopyridines was achieved under electrochemical conditions.Transition-metal-free and oxidant-free conditions are striking features of this protocol.A series of thiocyanated or selenocyanated imidazopyridines with a broad range of functional groups were synthesized in high yields.This method was also applicable to the thiocyanation or selenocyanation of some electron-rich arenes.This convenient method for the synthesis of thiocyanated imidazopyridines might be applicable in the field of pharmaceutical synthesis.2.Electrochemical Oxidative Regioselective C-H Cyanation of Imidazo[1,2-a] pyridinesElectrochemical oxidative regioselective C-H cyanation of imidazo[1,2-a] pyridines was developed using TMSCN with lower toxicity as the cyano source.The p H = 9 buffer solution and aceton itrile were used as the mixed solvent,without the addition of oxidizer and electrolyte in this transformation.A variety of C-3 cyanated imidazopyridine products were obtained in moderate to excellent yields under mild conditons.This electrochemical method may be applied to the field of drug development of imidazopyridine derivatives.