Study On Synthesis Of 3,6-Dihydro-2H-Pyran Derivative

Dihydropyranes is one of the Oxygen heterocycle that widely exist in natural,and many of which have phamacological activities,such as anti-tumor activity,anti-pathogenic microbial activity.The chemical synthesis methods of dihydropyran compoumds include Princes cyclization reaction of an alkyne?al?propanol with an aldehyde,[4+2]cycloaddition reaction of a diene with an aldehyde,intramolecular hydrogenation alkoxylation reaction,nucleophilic addition reaction of cerium ions and the intramolecular olefin metathesis reaction and CDC reaction.CDC reaction refers to the reaction process in which the hydrocarbon bonds in different reaction components in an oxidizing environment are directly dehydrogenated and then coupled to form carbon-carbon bonds or carbon-bond bonds.At present,it is widely used in the synthesis of organic compounds.The commonly used oxidants are persulfate,peroxide,manganese dioxide and dichlorodicyanobenzoquinone.On the basis of cross-dehydrogenation coupling reaction,this study aimed to study the synthesis method of substituted dihydropyrans and synthesize substituted dihydropyrans with potential pharmacological activities to establish the basis for the screening of new drugs.Firstly,4-phenyldihydropyran and dicarbonyl compounds were selected as the reactants.By studying the reaction conditions of catalyst,solvent and oxidant,it was obtained as dichlorodicyanobenzoquinone as oxidant,1,2-di Ethyl chloride is a synthetic reaction route of the reaction solvent indium triflate as a catalyst,and a cross-dehydrogenation coupling reaction model of substituted dihydropyrans is established.The reaction model was used to study the effects of different dicarbonyl compounds,different dihydropyrans and electron-rich aromatic rings on the reaction.23 compounds with dihydropyran structure were synthesized,and the reaction yield was between 71%to 92%.The chemical structures of 23 new compounds in the reaction were confirmed by high resolution mass spectrometry,¹H-NMR and¹³C-NMR.A method for the synthesis of 3,6-Dihydro-2H-Pyran derivative was successfully established by CDC reaction,whose reaction conditions were mild and whose operation was simple.Under these conditions,substituted dihydropyran can cross-dehydrogenate with a series of diesters of malonic acid,mandoles and isophenyl dimethyl ether,and generate3,6-Dihydro-2H-Pyran derivative with good yield.