Study On The Synthesis Of Sulfur Compounds With Aryl Sulfonyl Hydrazide Promoted By Iodine

Sulfur-containing organic compound is an important class of chemical.They exist mainly as sulfones,sulfoxides,and thioethers.These fragments can often be found in most of the natural products,drugs,and functional materials.Researches on sulfur-containing compounds and their synthesis always interested organic chemists.Recent years,a large number of synthetic methods to sulfur-containing organic compounds have been reported,and among them the construction of C-S bond is their main synthetic pathway.These excellent achievements have greatly promoted the development of organic sulfur chemistry.However,in some cases,the use of transition metals and sulfur reagent that is unstable,high toxic,and strong odorous can still be found,which does not meet the requirement of "Green Chemistry Concept".Therefore,it is of great significance to develop novel,efficient and green synthetic methods to sulfur-containing organic compounds.Recently iodine as a nonmetallic reagent and environmentally friendly arylsulfonyl hydrazide have received their application value in the synthesis of sulfur-containing compounds.Based on these outstanding results,we continued to carry out iodine-promoted and arylsulfonyl hydrazide-participated synthesis of organic sulfur compounds.This thesis contains the following two parts.Part ?:Tetrabutyl ammonium iodide promoted thioetherification of aromatic sulfonyl hydrazide with 4-hydroxycoumarin was studied.In this reaction,the sulfur source is arylsulfonyl hydrazide which is safe,stable and additive is HCl.The reaction of 4-hydroxycoumarin with arylsulfonyl hydrazide gave a series of 3-arylthio-4-hydroxycoumarin in medium to good yields.This novel method is characterized by mild reaction conditions,simple operation and use of non-metallic catalysis.In addition,the reaction system is also applicable to 1,3-dihydroxyquinoline substrate.A novel method for the synthesis of 3-arylthio-4-hydroxycoumarin was thus efficiently developed.Part ?:Study on the iodine-promoted synthesis of 2-aminothiadiazole employing KSCN as a sulfur source was investigated.This kind of three-component reaction using cheap potassium thiocyanate as sulfur source,aldehyde and arylsulfonyl hydrazide was first time reported.Thus a series of 2-amino-5-aryl-1,3,4-thiadiazole were efficiently synthesized.Simple reaction conditions and high utilization rate of atomic sulfur source are the two advantages.More importantly,aryl ketones substrates are also suitable for this reaction system resulting in the formation of 4-phenyl-1,2,3-thiadiazole compounds.In conclusion,two iodine-promoted and arylsulfonyl hydrazide-participated methods for the synthesis of sulfur-containing compounds were developed,which not only provided two novel methodologies for the synthesis of organic sulfur compounds,but also enlarged the application scope of sulfonyl hydrazides in organic synthesis.