Dehydrogenation Of Nitrogen Heterocycles Catalyzed By Graphene Oxide And Study On New Methods For The Synthesis Of Amides

N-heterocyclic structures are widely present in natural products,bioactive molecules and functional materials.Isoquinoline,quinoline,indole and quinazoline are the most important part of the nitrogen heterocyclic compounds,and their synthesis and preparation have caused extensive attention.Oxidative dehydrogenation of nitrogen heterocycles is an important strategy for obtaining isoquinoline,quinoline,indole and their derivatives,which shows the significance of oxidative dehydrogenation in organic synthesis.Amide is one of primary component of biomolecules,and it is also widely presented in natural products,pharmaceuticals,pesticides and functional materials.Therefore,the synthesis of amide compounds is of great significance.The research contents of this thesis include graphene oxide catalyzed dehydrogenation of nitrogen-containing heterocyclic compounds and study on new methods of amide synthesis.The details are as follows.(1)We have developed a method for the dehydrogenation of nitrogen-containing heterocyclic compounds under air atmosphere condition using graphene oxide(GO)as a catalyst and ethyl acetate as a solvent.Isoquinoline,quinoline,indole,quinazoline and their derivatives were obtained.The advantages of this method are broad substrate scope,inexpensive materials,metal-free,air compatible,the operation simple,the product is easy to separate and so on.This protocol provides an efficient and green approach for the dehydrogenation of nitrogen-containing heterocyclic compounds.(2)We have developed an effective and practical method for the synthesis of amide.The advantages of this method are metal-free,inexpensive formamides as amines source,mild condition,air compatible,extendable,high yield,simple operation and so on.This research provides a new way for the synthesis of amides.(3)We have developed new methods for the transamidation reaction.Including manganese-catalyzed transamidation reaction and metal-free involved transamidation reaction.(i)Manganese-catalyzed transamidation reaction.It does not need any acid,base,ligand,or other additives to achieve the transamidation reaction,DMF and other amides as acyl source.The advantages of this method are broad substrate scope,easily scaled up to gram-scale,and the amount of catalyst can be further reduced to 5 mol%,(ii)Metal-free involved transamidation reaction.Based on the research of manganese-catalyzed transamidation,we further explored that transamination reactions can be achieved through hydrogen bond activation between substrates.This strategy does not need any catalyst and additive,with broad substrate scope,high yield,and can be extended to gram-sacle.