Study On The Copper-Catalyzed One-Pot Synthesis Of Aziridine And Thiazole Compounds And Ring Opening Reactions Of Aziridines

Copper-catalyzed Ullmann-type coupling reaction serves the important strategy for the formation of C-C,C-N and C-O bonds.A sequential one-pot synthesis with reagents added to a reactor one at a time and without work-up which may improve the efficiency of synthesis and reduce the pollution of the solvent etc.Therefore the one-pot synthesis of heteroccylics by the copper-catalyzed Ullmann reaction has been highlighted as one of the research frontiers in organic chemistry.In the dissertation,the one-pot strategy of copper-catalyzed intramolecular Ullmann coupling was successfully applied in the synthesis of aziridine derivatives and the thiazole derivatives as well.Besides,the ring-opening properties of aziridine compounds were researched too.Using aromatic isothiocyanate and 2-bromoallylamine as starting materiels,the corresponding nucleophilic addition product thioureas could be converted into the aziridine derivatives by one-pot intramolecular copper-catalyzed Ullmann reaction.The optimized reaction conditions were set up by evaluating the reaction solvent,ligand,base,temperature and the amount of copper catalyst.The research results reveals that the reaction offered higher yields when dry DMSO used as solvent,15%CuI as catalyst,2.0 equivalents of K2CO3 as base,and under 100? for 4 hours.The optimized reaction conditions were applied to a range of aromatic isothiocyanates,and the reactions offered the corresponding aziridines in 51%to 83%yields.The one-pot procedure has some advantages such as readily available raw materials,cheap catalyst,easy of operation,mild reaction condition,and high yields.The research results showed that the one-pot reaction could offer substituted thiazoles when strong electron withdrawing group was attached to the benzene ring of aromatic isothiocyanates,which indicated the diversity-oriented synthetic strategy could be employed in the procedureThe ring-opening reactions of the aziridine derivatives were also investigated,the research work proved that the three-member strain aziridine ring would readily open when attacked by nucleophilc reagent and the reaction could afford corresponding ring-opening products.