S-Arylation And The Relevant Cyclization Of Thioanmides

Aryl-iosthioureas,N,N-dialkylbenzothiazoles,are of great importance in synthetic methods,pharmacochemistry and natural product chemistry.So it is of great significance to investigate their synthetic methods.This thesis mainly focused on S-arylation and the relevant cyclization of thioanmides.The details of the study are as follows:1.Copper-catalyzed(C-S)bond formation reaction by using arylthioureas and diaryliodonium salts as starting materials was investigated.The type and amount of the catalysts,the type and amount of the bases,the solvents,the temperature,as well as the molar ratio of the substrates were screened to obtain the optimal conditions(Cu Cl as catalyst,Cs2CO3 as base,DMSO as solvent,heating under 100 ~oC for 2h).Under the optimal conditions,a series of 22 aryl-iosthioureas were furnished in good yields(74%-88%).All the product structures were identified by necessary spectra.The broad substrate scope,short reaction time,mild reaction conditions,easy performance and good yields make this approach attractive.Therefore,this method provides an alternative protocol for the synthesis of aryl-iosthioureas.2.Facile synthesis of S-arylisothioureas via the S-arylation of arylthioureas with aryl iodides in water was expolored.After a series of screening and optimization,it was found that the reaction could be performed under the catalytic system of Cu SO4·5H2O/Cs2CO3/Bpy rapidly and efficiently.The reaction conditions are mild and yields are excellent,it also showed broad substrate compatibility.This protocol avoids the use of environmentally harmful solvents.Besides,easy performance,easily available raw materials make this protocol attractive.3.The synthesis of 2-aminobenzothiazole derivatives by using 2-halogen anilines and sodium dithiocarbamates as starting materials was studied.The optimal reaction conditions were obtained by screening a series of parameters.Under the optimal conditions,a series of 22 dithiocarbamates were furnished in good to excellent yields(66%-97%).This protocol features easily available raw materials,mild reaction conditions,good to excellent yield,showing its practical synthetic value for the preparation of some biologically or pharmaceutically active compounds.