Synthesis Of1,2,3-triazoles And1,4-dithiins Based On Aryl Alkynyl Sulfides

It has reported in many literatures that aryl alkynyl sulfides as important syntheticintermediates can be used in the field of organic synthesis to synthesize aryl alkynylsulfone, aryl alkynyl sulfoxide, thioester, alkenyl ether, heterocycle, substitutedalkynyl, etc. Furthermore, aryl alkynyl sulfides possess unique optical activities due totheir special conjugation between aromatic ring and unsaturated acetylene bond. Andthey are so prospective and valuable in the application of the optical material. On thebasis of the Su qiong’s work in our lab, who developed a one-pot strategy for preparingarylethynyl sulfides, aryl diyne sulfides, bis(arylethynyl) sulfides and conjugatedenyne sulfides by a large number of-thio carbonyl compounds as substrates. It isworth mentioning that the new one-pot method has the advantages of simplifiedprocess, higher total yield, also is a environment friendly methodology and has longbeen an attractive area of research.The1,2,3-triazoles, as important nitrogen heterocyclic compounds, have beenknown for their unique medicinal properties of anti-cancer, anti-bacterial,anti-tuberculosis when be build in drug molecules. Also the1,2,3-triazoles attractedmany biologists’ attation due to their action as herbicide and insecticide in the field ofpesticide. Moreover, their application in materials also caused a very widespreadconcern. Up to now, the methods for synthesis of1,2,3-triazoles are1,3-Dipolarcycloaddition and click chemistry, which need terminal alkynes as starting materials,but the synthesis of4-(alkylthio)-5-arylbutane-1,2,3-triazoles with unterminal aryldiyne sulfides has little attention until now. So it is important to explore new1,2,3-triazole compounds.The1,4-dithiins, six-membered heterocyclic compounds could be used asprotecting group, organic intermediate and monomer in organic synthesis. Dithiinesare an important class of compounds that exhibit a number of pharmacologicalproperties. They also find significance in several other areas. For instance, Obtainmaterials with specific properties through further structural modifcation. However,Known methods of synthesis of dithiines have the disadvantages of low yield, manyby-products, hard to get starting materials, use toxic agents and environmentalpollution. So the development of new environmentally friendly, simple operation andhigher total yield synthetic method is very necessary.This paper focus on the synthesis of1,2,3-triazoles and1,4-dithiins by the corresponding aryl alkynyl sulfides as substrates.Firstly, On the basis of the previous work of our lab, using one-pot three-stepprocedure to prepare aryl diyne sulfides(54a-54d) by4-(alkylthio)-1-arylbutane-1,3-dione as substrates and prepare bis(arylethynyl) sulfides(57a-57k) by substratesbis(arylethanonyl) sulfides as substrates.Secondly, aryl diyne sulfides were used as the starting material, reacted withsodiumazide via Huisgen1,3-Dipolar cycloadditon, synthesized a series of4-(alkylthio)-5-arylbutane-1,2,3-triazoles (65a-65d). These1,2,3-triazoles weredescribed for the first time, we also give a reasonable explanation for the formation ofthe major products.Finally, bis(arylethynyl) sulfides were used as the starting material, reacted withtitanium via cyclization reaction, synthesized a series of2,6-Diaryl-1,4-dithiins(67a-67k). This method is not only simple and mild, but also high yield, does notrequire a tedious separation of the reaction mixtures. The method of preparing2,6-Diaryl-1,4-dithiins by bis(arylethynyl) sulfides substrates was described for thefirst time and the possible reaction mechanism of the cyclization was also proposed.2,6-bis(4-methoxyphenyl)-1,4-dithiine (67a) was characterized by X-ray single crystaldiffraction and the configuration was decided.All aryl alkynyl sulfides and target compounds in this paper were identified by1HNMR,13C NMR, IR, MS and HRMS.