Method For Efficiently Synthesizing Diversified Fused Heterocyclic Compounds

Heterocyclic compounds are a very important class of organic compounds.Up to now,the number of heterocyclic compounds found or synthesized has reached tens of millions;about half of the known organic compounds contain heterocyclic structure.Heterocyclic compounds can be divided into two classes,monoheterocycles and fused heterocycles.Fused heterocyclic moieties are widely found as key structures in numerous natural products and synthetic compounds with extensive biological activities.Different from well-studied and developed bicyclic heteroatom-containing skeletons,the broad potential biological activities of fused tricyclic compounds have not been fully explored due to the synthetic challenges of the general formation of the unique tricyclic skeletons.In the article,the synthesis of 2-(4-oxo[1,2,3]triazolo-[1,5-a]quinoxaline-5(4H)-yl)-acetamide derivatives was studied.Based on relevant literature research and a large number of experiments,we got a simpler synthesis method,the protocol employs a Ugi four-component reaction for the assembling of N-(2-haloaryl)propynamide intermediates and followed by a copper-catalyzed tandem reaction of the synthetic N-(2-haloaryl)propynamides with sodium azide.The tandem reaction gives2-(4-oxo[1,2,3]triazolo[1,5-a]quinoxaline-5(4H)-yl)acetamide.Such a method provides rapid access to structurally varied and complex fused tricyclic scaffolds through readily available starting materials.