Studies Of Microwave-assisted C-S Bond Formation And Copper-catalyzed C-Se Bond Formation Reactions

C-S bonds and C-Se bonds are widely found in biologically active molecules,drugs,intermediates and functional materials.The reaction for construction C-X(X=S,Se)bonds is one of the important contents in organic synthesis.How to efficiently and simply build C-X(X=S,Se)bonds is one of the hotspots of research in recent years.Therefore,exploring green and efficient method for C-S and C-Se bonds formation is still challenging.The research work of this paper mainly includes three aspects,as follows:1.In this thesis,the coupling reaction of imidazo[2,1-b]thiazoles with sulfonyl hydrazides is realized by microwave-assisted organic synthesis technology(MAOS).Aryl-and methyl-sulfenylated imidazo[2,1-b]thiazole compounds were synthesized with high regioselectivity and the yields were ranging form 62%to 87%.The reaction exhibited the advantages of short time,good regioselectivity,high yield,and water as a solvent,while avoiding the use of catalysts,and the reaction substrate has good functional group tolerance.2.In this thesis,the three-component coupling reaction of phenol,selenium powder and aryl iodobenzene was realized by using Cu(OAc)₂as the catalyst and Na₃PO₄·12H₂O as the base.A series of ortho-aryl phenol selenoether compounds were synthesized for the first time with yields of 67%-87%.The method using elemental selenium available on the market as selenization reagent,avoids the application of expensive organic selenium reagents.The construction of C-Se bonds occurs in the ortho position of phenol with high regioselectivity.3.In this thesis,the multi-substituted phenol compounds were synthesized from 1,3-dicarbonyl compounds and DMSO in one step,using Cu SO₄·5H₂O as a catalyst at 120?.The products were obtained in yields 77%-93%.When treating with asymmetric 1,3-dicarbonyl compounds,two cyclized products were separated.Mechanism studies show that DMSO participates the cyclization process and provides the carbon source at C2 position of phenol ring.This study provides a new way for the synthesis of functionalized phenol derivatives.