Transition Metal Copper-, And Palladium-catalyzed Synthesis Of Nitrogen-containing Heterocyclic Compounds

Heterocyclic compounds play an essential role in the life foundation. Moreover, with the development of science and technology, heterocyclic compounds have deeply influence on the human daily activities. Up to date, these types of small molecules are one of the largest classes of organic compounds. A plenty of small heterocycles are widely existed in various bioactive natural compounds, organic materials, agricultural chemiscals, and pharmaceuticals. From the academic point of view, a number of complicated heterocyclic structures display special molecular architectures and their synthetic methods still remain interesting challenges.Heterocyclic synthons appeared frequently in organic synthesis demonstrate that its significance in the fields of chemistry. Numerous synthetic methods, especially in the preparation of multifunctional heterocyclic molecules, are based on the cyclization of appropriate acyclic precursors; however, these methods suffer from expensive reagents and solvents, harsh reaction condition, and long reaction time. Therefore,continuing researching on development of some new efficient synthetic methods,including using the cyclization of acyclic precursors, has attracted much attention from a number of chemists. However, some transition metal catalysts suffer from at least more than one of the drawbacks such as air- and moisture sensitive, expensive,harsh condition, tedious workup and so on, which limit the research and development of organic synthesis of heterocyclic compounds. Thus, my research topic is to employ the commercial available and cost-efficient catalyst such as copper, and palladium to synthesize the nitrogen-containing heterocyclic compounds. The details are as follows:1. Synthesis of the new symmetrical 2, 4-diarly, and unsymmetrical 2, 4-diaryl- 2-aryl-4-alkyl triazines used the commercial available amidines with DMF which serves both as a one-carbon supplier and reaction media in the presence ofCuI/pyridine catalytic system in molecular O2 atmosphere. Considering the potential value in the biology, materials and coordination chemistry, this synthesis method may be widely used in the future.2. Use of electron-deficient aryl bromides in the presence of bromobenzyl-substituted imidazoles allows the synthesis of 5-aryl imidazoles in high yields without cleavage of the benzyl C-Br bond in the presence of Pd catalyst. Then, an intramolecular Pd-catalyzed C-H activation reaction affords 9Hdibenzo[c,e] imidazol[1,5-a]azepines derivatives successfully.