Synthesis Of Sulfur-containing Heterocyclic Compounds Via Tandem Reactions

Sulfur-containing heterocycles can be widely found in many natural products andpharmaceuticals, which display a wide range of biological and pharmacologicalactivities. Compounds containing those frameworks are also considered as buildingblocks for the construction of numerous compounds. Therefore, many organicchemists are paying close attention to synthesis of sulfur-containing heterocycles.A tandem reaction is a consecutive series of intramolecular organic reactionswhich often proceed via highly reactive intermediates. The substrate contains manyfunctional groups that take part in chemical transformations one at the time. Often afunctional group is generated in situ from the previous chemical transformation. Themain advantages of a tandem reaction in organic synthesis are that the reaction isoften fast due to its intramolecular nature, the reaction is also clean, displays highatom economy, does not involve workup and isolation of many intermediates, andadds much complexity in effectively one step.In this dissertation, we described the systhesis of2-iminobenzo-1,3-oxathioles,4-benzylidene-4H-benzo[d][1,3]thiazines,1,3-Dihydrobenzo[c]thiophene-imines and2-subsituted-benzothiazoles derivateives via tandem reaction.This dissertation is mainly consists of the following four Parts:1) We introducedour results that2-iminobenzo-1,3-oxathioles derivatives were synthesized from2-iodophenols and isothiocyanates in water via copper-catalyzed tandem reaction;2) We have developed novel strategies for the construction of4-benzylidene-4H-benzo[d][1,3]thiazines through tandem reactions between2-alkynylbenzenamine and carbon disulfide;3)1,3-dihydrobenzo[c]thiophene-iminewere efficiently synthesized from o-(1-alkynyl)benzamides and Lawesson’s Reagent;4) We described the reaction of tosylhydrazone with2-Mercaptobenzothiazoles, afacile approach to synthsize2-subsituted-benzothiazoles derivateives under transitionmetal-free condition.