A Study On The Catalyzing Reaction Of2-mercaptobenzothiazoles Synthesized By Ortho-haloanilines

2-mercaptobenzothiazoles, categorized as significant chemical raw materials, havefrequently been used as core structures of pharmaceutical agents and advanced materialsand other fields.Some approaches to the synthesis of2-mercaptobenzothiazole derivatives have beendeveloped, the most commonly methods include the condensation of ortho aminothiophenols with carbon disulfide or N, N-diphenylthioureas with sulfur. Some of thereported methods for the preparation of2-mercaptobenzothiazoles have the drawbacks ofhaving a limited substrates scope, which limited the application of2-mercaptobenzothiazoles. Another procedure for obtaining2-mercaptobenzothiazolesadopted in the industry involved ortho-nitrochlorobenzene, phenyl amine and the mixtureof nitrobenzene and aniline. The methods based on the direct use of carbon disulfide andoften suffered from complex production process, harsh conditions and low yields.In this dissertation, we report copper or iron used as inexpensive catalysts and organicligands mediated cascade reaction that halo anilines bearing an ortho-halogen substitutionwith potassium O-ethylxanthate to produce2-mercaptobenzohiazoles in high yields. Thedemonstrated approach can be applied to the synthesis of2-substitutedmercaptobenzothiazoles with different substituents and given products with high purity andin short reaction time.The main works of the paper are show as follows:1. Under the protection of inert atmosphere, we adopted CuI as catalysts andobtained2-mercaptobenzothiazoles (C7H5NS2) through the reaction of O-haloanilines and Potassium ethylxanthate, then the application of this method onthe substrates with different subsitituents was investigated.2. Under the protection of inert atmosphere, the best reaction conditions tosynthesis2-mercaptobenzothiazoles, such as the kinds of iron catalysts,reaction time and temperature, the type of ligands, as well as the effect of base,acid and the solvent on the reaction were investigated by using2-iodoanilineand potassium ethylxanthate as raw materials.3. The best reaction conditions optimized via the reaction of O-haloanilines and potassium ethylxanthate: using10mol%CuI or FeF3as catalysts and5mol%2,2’-bis(diphenylphosphino)-1,1’-binaphthyl as ligand in DMF at110℃, andthe highest yield reached to99.5%.4. Under the optimized reaction conditions, the four kinds of2-mercaptobenzothiazole compounds:2-mercaptobenzothiazole(C7H5NS2),6-fluro-2-mercaptobenzothiazole(C7H4FNS2),6-methyl-2-mercaptobenzothiazoles(C8H7NS2),6-trifluoromethyl-2-mercaptobenzothiazole(C8H4F3NS2) were synthesized by the reaction of.2-chloroaniline(C6H6ClN),2-bromoaniline(C6H6BrN),2-iodoaniline(C6H6IN),4-fluro-2-iodoaniline(C6H6FIN),2-iodo-4-methylaniline(C7H8IN),2-iodo-4-(trifluoromaethyl)aniline (C7H5F3IN) with potassium ethylxanthate, respectively. And the components and structures ofall products were characterized by MS and NMR and their molecularstructures were testified.5. The catalytic reaction mechanism of O-haloanilines and potassiumethylxanthate was speculated through consulting the literature and detectingthe reaction process.