Study On The Synthesis Of Pyrano[3,2-c]Pyridone, Pyrano[4,3-b]Pyranone And2H-pyran-2-one Derivatives

The development of novel methods for the preparation of heterocycles and the search for newheterocyclic compounds with interesting structure and property have always been a hot topic in organicsynthesis and medicinal chemistry.To develop novel procedures for the preparation of heterocyclic compounds, the first part of this thesisfocuses on the synthesis of pyrano[3,2-c]pyridone and pyrano[4,3-b]pyranone derivatives and their hybridswith pyrimidine nucleoside through one-pot multi-component reaction under microwave irradiation.Specific studies are as follows:Three-component reaction of aldehyde,4-hydroxy-pyridin-2(1H)-one or4-hydroxy-2-pyranone andmalononitrile was carried out efficiently under microwave irradiation in [bmim]BF4. Through this reaction,a series of pyrano[3,2-c]pyridone and pyrano[4,3-b]pyranone derivatives were obtained. Compared withliterature methods, this novel procedure showed such advantages as readily available starting materials,enhanced efficiency and an environmentally benign nature. In addition, the procedure was successfullyapplied in the preparation of pyrimidine nucleoside-pyrano[3,2-c]pyridone and pyrimidine nucleoside-pyrano[4,3-b]pyranone hybrids.In the second chapter, a novel procedure for the preparation of4,6-disubstituted,3,4,6-trisubstituted,4,5,6-trisubstituted and3,4,5,6-tetrasubstituted2H-pyran-2-ones through the tandem reaction of allenicalcohols under the promotion of Br nsted acid in dichloromethane was developed. Compared withliterature methods, this new strategy showed such advantages as rapid reaction, mild conditions, and highefficiency. Interestingly, indane derivatives could also be obtained via an acid catalyzed tandem reaction ofthe specifically substituted allenic alcohol substrates.