I₂-catalyzed Synthesis Of The Five-or Six-membered Heterocycles Containing Nitrogen

Nitrogen-containing heterocyclic compounds are one of the most important heterocyclic compounds,therefore,the synthesis of five and six membered nitrogen-containing heterocycles has attracted great attention of many chemists to research in this field.In this paper,we will summarize the synthesis of multi-substituted imidazoles and 1,2,4-triazines,mainly consists of the following four parts.Firstly,imidazoles have a wide range of application as important five-membered heterocyclic compounds.They have excellent biological activity and play an important role in pharmaceutical chemistry,materials chemistry and organic synthesis chemistry and other areas.So far,a large number of synthetic multi-substituted imidazoles have been reported.In this paper,we will summarize and review it.Secondly,1,2,4-Triazine is a prominent structural core system present innumerous natural and synthetic biologically active compounds,many efforts have been focused on the preparation of those privileged scaffolds.Thirdly,a novel and efficient I₂ / TBPB mediated oxidative synthesis of 1,2,5-triaryl-1Himidazoles through the reaction of aryl acetaldehydes and amidines has been developed.Importantly,inexpensive catalysts,no ligand,an excellent functional groups tolerance to the desired compounds.Lastly,I₂-catalyzed synthesis of 1,2,4-triazines via [4 + 2] domino annulation reaction of aryl alkenes and amidrazones in one-pot has been developed.The overall process involves three different reactions: iodination,Kornblum oxidation and condensation.