Studies On The Synthesis Of Heteroaromatic Compounds

The synthesis of heterocyclic compounds by catalytic dehydrogenation process has become one of the most effective methods for the construction of natural active substances,drug molecules and biomaterials due to its high atomic economy.However,achieving a more environmentally friendly reaction,making reaction conditions moderate and extensive applicability become the focus of research.This thesis mainly introduces two synthesis methods for the preparation of aromatic heterocyclic compounds.One is palladium-catalyzed ligand-free and the other one is base mediated under transition metal-free conditions.The contents are as follows:In chapter one,we reviewed the research progress about the synthesis of heterocyclic compounds with transition metal and non-transition metal in recent years.In chapter two,palladium-catalyzed synthesis method for preparation of heterocyclic compounds has been developed.It can be carried out smoothly without adding additional ligands.The method utilizes palladium catalyst to achieve a catalytic dehydrogenation process with good yields and large scope.In addition,the dehalogenation test of the reaction confirmed that tetrahydroquinoline could be used as a hydride precursor for transfer hydrogenation(dehalogenation)reaction.In chapter three,a synthesis method of heterocyclic compounds with no transition metal under base conditions has been developed.This reaction can effectively realize the dehydrogenation process under the combined action of potassium tert-butoxide and oxygen.The reaction has the advantages of environmentally friendly,high yield,extensive functional group tolerance and so on,and more in line with the concept of green chemistry.Preliminary mechanism studies have shown that the reaction may proceed under a superoxide radical process.