The Transition Metals-catalyzed C-S Bond Formation Reactions Starting From 2-Substituted Anilines

Heterocyclic chemistry is one of the most active research fields in organic chemistry.Among them,benzothiazoles and benzoxazoles are the representative compounds.Due to their universal biological activities like antimicrobial,anti-inflammatory and anti-tumor activity,they are used widely in biomedical?agricultural pharmacology and material fields.Metal free or transition metal catalyzed C-X formation is one of the most hot research in organic chemistry that attract a lot of science researcher's attention.There are reporting that the formation of C-S bond plays an important role in agricultural pharmacology?biomedical and material fields.This thesis mainly studied the C-S bond formation,to synthesis the benzothiazole and benzoxazole derivatives using 2-substituted anilines as starting materials and transition-metals as catalysts.In addition,the synthesis of phenyl dithioformates using phenylboronic acids and dimethyl dithiocarbamate sodiums as starting materials were also studied.The research details include four parts as follows:1.The synthesis of benzothiazole derivatives by using 2-halogen anilines and dithiocarbamates as starting materials was studied.After a series of screening and optimization,we found that the reaction could be performed under the catalytic system of t-BuOK/CuO/Pd?PPh3?4 rapidly and efficiently,with mild conditions and excellent yield,it also showed broad substrate compatibility.2.The transition-metal cayalyzed synthesis of benzothiazole derivatives by using2-halogen aniline and thiocarbamoyl chloride as starting materials was investigated.After screening and optimizing the conditions,the system of t-BuOK/CuBr/Pd?dba?₂ could catalyze the synthesis of benzothiazoles conveniently and efficiently.The broad substrate scope,short reaction time,mild reaction conditions,easy performance and nice yields make this approach attractive.Therefore,this method providing an alternative pathway for the synthesis of 2-aminobenzothiazoles.3.Copper catalyzed synthesis of benzoxazole and benzothiazole derivatives via one pot manner was expolored.After a series of conditions screening,we obtained the optimal conditions and a series of 17 different substrated benzoxazoles and benzothiazoles were obtained?74%-91%?under the optimal conditions.This protocol features easily available raw materials,simple operation,good to excellent yield,showing its practical synthetic value for the preparation of some biologically or pharmaceutically active compounds.4.Copper-catalyzed C-S bond formation reaction for the synthesis of dithiocarbamates was studied.The optimal reaction conditions were obtained by screening a series of conditions.Under the optimal conditions,a series of 20 dithiocarbamates were furnished in good to excellent yields?71%-91%?.The wild substrates adaptability,short reaction time,mild conditions and easy operation are the merits in this reaction,proving a new synthetic method for phenyl dithiocarbamate derivatives.