Study On The Method Of Novel Imidazo[1,2-a] Pyridines And Imidazo[1,2-a] Thiochromeno[3,2-e] Pyridines

Thioamides as a class of particular polarized ketene N,S-acetals with generalstructures, have proven to be important building blocks in the construction ofheterocyclic systems. Reactions of these ketene acetals with1,2-and1,3-bis-acceptorsubstrates leading to five-and six-membered heterocycles have been reportedrepeatedly in the past decades. This paper focuses on two methods of nitrogen(sulfur)-containning fusedheterocycles which could be to discover new bioactive usingnovel thioamides as synthons.First, the progress of the important application in the field of organic synthesisabout thioamides (polarized ketene N,S-acetals) was briefly introduced. Meanwhile，the environmentally benign methods by using multicomponent reactions (MCRs),microwave-assisted combinatorial synthesis (MACS) and solvent-free reactions(SFRs) were summarized.In the second chapter, the procedure for the synthesis of novel ethyl2-(3-oxo-3-arylpropanethioamido)acetates were briefly introduced. Imidazo[1,2-a]pyridines have been synthesised with novel ethyl2-(3-oxo-3-arylpropanethioamido)acetates under microwave irradiation and the reaction conditions were alsoinvestigated. The results showed that imidazo[1,2-a]pyridines (4a-4o) can be achievedin good yields with DABCO as catalyst under microwave irradiation.The third chapter was based on the chapter two, when ethyl2-(3-(2-haloaryl)-3-oxopropanethioamido)acetates were used as synthons, a new typeof imidazo[1,2-a]thiochromeno[3,2-e]pyridines have been found and it gave a highyield under solvent-free condition.The structures of all the synthesized compounds were characterized by IR,1HNMR,13C NMR, and HRMS. Two single-crystals (4f and5k) were cultured and the structure of the unknown compounds could be conveniently confirmed by X-raysingle-crystal diffraction analysis.