Synthesis Of Multi-substituted 4H-pyran Compounds Via Multi-component One-pot Reaction

pyran derivatives were basic structural units of many natural products with a wide range of biological activities, such as anti-inflammatory, antibacterial and insecticidal. In addition, the pyran[2,3-c] pyrazole also have activity of anticancer and antifungal. Indole derivatives have long been the focus of considerable attention of chemical and biological researchers due to their extensive applications in biological and pharmacological area.Multicomponent reactions can efficiently generate three or more chemical bonds at the same time without isolating. This kind of reaction is one of the best tools in modern organic synthetic chemistry, because it can convert all atoms in reactants into target product.The chapter one was a introduction to introduced the pyrazole, pyran, Isatin-Based Hetero-cycles and MCRs.The chapter two was introduced DABCO-catalyzed multi-component one-pot reactions for the convenient synthesis of multi-substituted pyrano [2,3-c] pyrazole derivatives. A highly efficient strategy for the synthesis of multi-substituted pyrano [2,3-c] pyrazole derivatives is discribed via multi-component one-pot method with isatin（or acenaphthenequinone）, 1-methylthio-1-methylamino-2-nitroethylene, hydrazine and ethyl acetoacetate catalyzed by（DABCO）.The chapter three was introduced Et3N-catalyzed multi-component one-pot reactions for the convenient synthesis of pyrano[2,3-c] pyrazole. An efficient and environmentally benign reaction process of 1,3-dicarbonyl compounds, 4-Hydrazinyl benzoic acid, malononitrile and Dimethyl acetylenedicarboxylate was developed for the convenient synthesis of pyrano[2,3-c] pyrazole. This reaction was conducted in Et OH catalyzed by Et3 N in good yields.The chapter four was introduced Rapid and efficient one-pot synthesis of pyrano[2,3-c] Pyrazole derivatives catalyzed by InCl₃ under ultrasound irradiation. An efficient and green procedure was developed for one-pot synthesis of pyrano[2,3-c]pyrazole via four-component reaction of β-ketoester, hydrazine, ethyl benzoylacetate（or methyl benzoylacetate） and malononitrile in 50% Et OH catalyzed by InCl₃ under ultrasound irradiation.