The monovalent copper catalyzed azide and alkyne cycloaddition,that is CuAAC reaction,has been widely used in biological research,materials science and drug molecular design,and the copper-catalyzed multicomponent reaction from azide and alkyne can effectively construct complex heterocyclic compounds.In addition,the product of CuAAC reaction,N-sulfonyltriazole,plays an important role in organic synthesis and can participate in many reactions to prepare novel compounds.Therefore,the copper-catalyzed azide-alkyne cycloaddition reactions and the multi-component reactions have been the focus of attention of chemists.In recent years,studies on CuAAC reactions and copper-catalyzed tandem reactions have been reported continuously.In particular,methods for the synthesis of triazole compounds have made great progress.However,there are still some limitations in literatures about synthesizing triazoles:too many additives to be used in the reaction;some catalyst systems are too complex to prepare;using organic reagents as solvents or limited substrate scope,etc.Therefore,it is still of scientific significance to find a simple,green,efficient and versatile catalytic method for the copper-catalyzed azide-alkyne cycloaddition reaction and multi-component reaction.In this paper,we carry out the following three parts of research with this goal:Part one:The optimal reaction condition for copper-catalyzed azide and alkyne cycloaddition reactions was explored.Using copper sulfate/substituted thiourea as the catalyst system,the cycloaddition reaction of organic azides and alkynes was performed in one-pot process to provide triazole compounds,the yield is up to 99%.This method avoids adding too many additives in the reaction,uses water as a solvent for the reaction conditions,has a wide range of substrates and has great industrial application potential.Part two:The cycloaddition reaction between the sulfonyl azide and the terminal alkyne was further studied,and the application scope of the copper sulfate/substituted thiourea catalytic system was extended.It was found that CuSO4·5H2O/substituted thiourea can be used as a highly efficient monovalent copper catalyst system to prepare the N-sulfonyltriazoles.Compared with the existing methods,the method has the following advantages:mild reaction conditions,green solvent,saving the amount of additives,low reaction cost,wide substrate scope and so on.Part three:The copper-catalyzed three-component reaction of azide,alkyne and 2-aminobenzaldehyde was explored.With the optimized conditions in hand,the reaction was highly efficient to yield the imino-1,2-dihydroquinoline compounds.This method has a high atomistic economic efficiency,and almost no by-products generates in the reaction,and the operation is simple and rapid,which is beneficial to the application in industrial production. |