Studies On The New Reaction Of Ketene Dithioacetals And Indole Derivatives:Synthesis Of Substituted Thiophenes

Multi-substituted thiophenes are an important class of sulfur-containing heterocyclic compounds that are widely used in materials chemistry and organic synthesis.Multi-substituted thiophenes can be synthesized by classical Paal-Knorr reaction,thiophene direct functionalization reaction,etc.However,there are often problems such as the use of highly toxic thio reagents and the need for multi-step reactions in the synthesis.Dithioketene is an important intermediate in organic synthesis.It has many reactive sites and can be used in the synthesis of various carbon and heterocyclic compounds.In this research group,many important organic compounds have been synthesized from dithioketene.In this paper,based on the previous research work,we developed a kind of cyclization reaction of dithioketene with N-unprotected indole under mild conditions,and synthesized a series of polysubstituted thiophene,which provided a new and simple method for the construction of indole thiophene double heterocyclic compounds from easily available raw materials.In this reaction,indole-thiophene biheterocyclic compounds were synthesized with high yield through electrophilic substitution in series/intramolecular cyclization/aromatization reaction.The reaction has the advantages of mild reaction conditions,simple raw materials,environmental protection,simple operation and strong universality.The structures of the series of indole-thiophene heterobiaryl compounds synthesized in this paper have been confirmed by ¹H-NMR,¹³C-NMR,high-resolution mass spectrometry,and single crystal ray diffraction experiments.