Synthesis Of Polysubstituted 4-Amino-iminocoumarins And 3-Hydroxyimidazo[1,2-?]Pyridine

Heterocyclic compounds widely exist in the nature, used in medicine, materials, dyes,plastics, pesticides, biological and other fields. At the beginning of this century, the discovery of Click chemistry leads to the discovery of a new method for the efficient synthesis of heterocyclic compounds, i.e., use the Click Reaction to synthesize ketenimine intermediates based on copper catalytic reaction on the terminal alkynes and azide compounds, followed by reaction with nucleophiles to yield new heterocyclic compounds. This method is highly selective, fast reaction rate, high yield and less by-product. It is one of the important pathways for the synthesis of heterocyclic compounds. In this paper, analyze the use of copper catalyzed synthesis of ketenimine intermediates, and the reaction between intermediates and nucleophilic reagents.This paper is divided into three parts.The first part, briefly state the introduction and application of ketenimine intermediates.The second part details the synthesis of multi-substituted 4-amino-iminocoumarin and 4-aminoquinoline. That is, copper-catalyzed terminal alkyne reacted with azide compounds to produce ketenimine intermediates. With the reaction between ketone imine intermediates and 2-hydroxybenzonitrile or 2-aminobenzonitrile, obtain multi-substituted 4-amino-iminocoumarin and 4-aminoquinoline in one pot synthesis. In this reaction, easily obtainable terminal alkynes, sulfonyl azides and 2-hydroxybenzonitrile or 2-aminobenzonitrile as substrates, heat under nitrogen protection to complete the reaction to produce the final product. The process is simple to operate, has a good substrate range and the product is novel.The third part, 3-hydroxyimidazo[1,2-?]pyridine derivatives preparation process. Copper catalyzed synthesis of terminal alkynes reacted with azide compounds to obtain ketenimine intermediates, followed by the reaction with 2-aminopyridine to produce new intermediates amidine. The reaction of the intermediate with the Cul / I2 / KI mediated N-(2-pyridyl)-amidine in the presence of KO'Bu is carried out by the direct double C-H functionalization of the C(sp3)-H bond to form a quaternary carbon atom . Synthesizing 3-hydroxyimidazo[1,2-a]pyridine derivatives. The experimental results show that the oxygen of the hydroxyl group can be introduced from water or KO'Bu in the reaction system. The successful implementation of the reaction further indicates that the amidine is rich in reactivity under various reaction conditions, which is simple to operate and has a good substrate range.