Synthesis Of Nitrogen-containing Heterocyclic Compounds Using Tandem Organic Reaction

The nitrogen-containing heterocyclic compounds are a very important class of small organic molecules that are widely in nature, many of them have the biological activity and become the core skeleton such as pharmaceuticals, pesticides and organic functional materials. Therefore, the development of new reactions, new methods and new strategies for the synthesis of nitrogen-containing heterocyclic compounds has been a research hotspot in the field of organic chemistry. In this dissertation, we summarized the development for the synthesis of nitrogen-containing heterocyclic compounds promoted by small organic molecules, and described the new reactions and new methods for the synthesis of pyrroles, indolizines, and quinolines via organic tandem reaction. The main contents are as following:Firstly, we described the pyridine-promoted one-pot multicomponent tandem reaction (ABC2type) of primary amine, ethyl glyoxylate and a-bromo aromatic ketone to provide novel polysubstituted pyrrole derivatives. The reaction involves the assembling of [2+1+1+1] atom fragments and the formation of four new bonds. The reaction conditions are mild and easily operated, and this methodology provides a new and effective way for the synthesis of polysubstituted pyrrole derivatives. Furthermore, by combining with a palladium-catalyzed oxidative decarboxylative coupling reaction, this chemistry provides a rapid access to a highly substituted benz[g]indole.Secondly, we described the one-pot multicomponent tandem reaction of pyridine, glyoxylate and a-bromo aromatic ketone to give novel indolizine derivatives. The piperidine-promoted AB3type four-component tandem reaction of a-bromo aromatic ketone and pyridine for the synthesis of indolizine derivatives was also developed. The mechanism of the novel reactions was proposed involving the formation of pyridinium ylides and α,β-unsaturated ketones with subsequent1,3-dipolar cycloaddition and aromatization reaction. Finally, we described the DBU-promoted tandem reaction of a-amino ketones and vinyl sulfonium salts for the synthesis of1,1-cyclopropane amino ketone derivatives, and the latter were oxidated by diethyl azodicarboxylate to give the synthesis of quinoline derivatives. The methodology provides a general access to1,1-cyclopropane aminoketones and their conversion into2-benzoyl quinolines. We proposed a plausible reaction mechanism.