Construction Of Nitrogen-Containing Heterocycles And Functionalization Based On Carbon C-H Activation

Heterocyclic chemistry,as a key component in the field of organic chemistry,plays an important role in modern organic synthesis reactions.In particular,the research of nitrogen-containing heterocyclic compounds has more application value.Nitrogen-containing heterocycles has pivotal positions in the development of natural products and small molecule active drugs.For example,indazole,benzimidazole,indole,quinoline derivatives have remarkable effects in anticancer,antibacterial,antimalarial,etc.More and more chemists are interested in the construction and functionalization of nitrogen-containing heterocycles.There are many traditional methods to construct nitrogen-containing heterocycles,but with limitations on them.How to construct nitrogen-containing heterocycles that cannot be synthesized by traditional methods;how to construct nitrogen-containing heterocycles with many synthetic steps,high cost and low yield in traditional methods;how to construct nitrogen-containing heterocycles with poor compatibility of functional groups,harsh reaction conditions and poor environmental friendliness existing in traditional synthesis methods.These problems make us continue to explore new methods to construct nitrogen-containing heterocycles.Professor B.M.Trost put forward the concept of “atomic economy”,which mainly emphasizes improving the atomic utilization rate of reactants.Professor P.A.Wender proposed the concept of “step economy”,which emphasizes the reduction of reaction steps.“One-pot method” and “series reaction” are advocated to be applied to the construction and functionalization of nitrogen-containing heterocycles.Transition metal catalyzed C-H activation has been applied to the construction and functionalization of nitrogen-containing heterocycles in the field of modern organic chemistry.In addition,the “series reaction”method to construct nitrogen-containing heterocycles has also been studied as a hot topic.Based on the above research background,this paper reports the use of transition metal catalyzed C-H activation method and the idea of “series reaction” to develop the construction of two nitrogen-containing heterocycles,and a new method for functionalization of nitrogen-containing heterocycles.The method features wide substrate application range,high atom economy,few reaction steps and high yield.The specific contents are as follows:(1)platinum chloride is used as a catalyst and C-H activation method is used to realize functionalization and introduction of methoxy groups at C5 and C6 positions of quinoline;(2)Using palladium acetate as a catalyst to form a nitrox source as a nitro source C-H activation,series reaction,direct nitration,cyclization to construct 3-nitro-1-(phenylsulfonyl)-1H-carbazole skeleton;(3)Cobalt nitrate participates in the synthesis of2,5-diphenyl-1,3,4-oxadiazole skeleton.