1,2-Diaza-Cope Rearrangement Of β,γ-Unsaturated Hydrazones With Acetate/H₂O

Hydrazone and its derivatives are common compounds in the field of medicinal chemistry,which have the characteristics of easy synthesis and diverse biological activities.In addition,it is also one of the key raw materials in industrial production and scientific research.It can participate in various chemical transformations to synthesize a series of biologically active compounds.These transformations open a door for the synthesis of small molecular compounds with more complex structures.Therefore,this thesis will focus on the transformation of hydrazones to carry out a review and research.The first chapter mainly introduces the application of hydrazone and its derivatives in the medical field,such as the specific drug Dantrolene.Then,staring from the structure of hydrazone functional group（nucleophilic nitrogen atom,electrophilic imine carbon atom and acidic N-H proton）,we systematically overviewed the conversion reactions of hydrazone and its derivatives as organic intermediates.The main contents are as follows:on the one hand,hydrazones can synthesize functionalized olefins by diazo compound intermediates;on the other hand,hydrazones can be converted to nitrogen-containing heterocyclic compounds through nitrogen center radical intermediates.The second chapter,based on the above research background,we chooseβ,γ-unsaturated hydrazones as the research object and discovered Ph I（OAc）₂-promoted 1,2-diaza-Cope Rearrangement ofβ,γ-unsaturated hydrazones with acetate.It can synthesize a series of diacyl N-allylhydrazines.A series ofβ,γ-unsaturated hydrazones derived from aromatic aldehydes are suitable for this conversion.The reaction does not require a metal catalyst and the reaction conditions are mild.Even if the volume is expanded to 1.0 mmol,the yield can still be as high as 75%,which provides the possibility for practical production and application.From the perspective of reaction mechanism,this process may involve hydrazone radicals and N-I（Ⅲ）intermediates.The dimethyl group at the allylic position provided the driving force of the[3,3]-rearrangement.The third chapter,on the basis of the research on the 1,2-diaza-Cope Rearrangement ofβ,γ-unsaturated hydrazones,we choose H₂O as the nucleophile to further explore the1,2-diaza-Cope rearrangement ofβ,γ-unsaturated hydrazones with H₂O.To one’s delight,this reaction can efficiently synthesize a series of acyl N-allylhydrazines at room temperature.In addition,it is worth noting that the electronic properties of the phenyl and N-phenyl moieties in theβ,γ-unsaturated hydrazones has no distinct effect on the yield of the reaction.The forth chapter,conclusions and prospects.On the basis of our previous1,2-diaza-Cope rearrangement ofβ,γ-unsaturated hydrazones with acetate/H₂O,we will continue to useβ,γ-unsaturated hydrazones as the substrates and investigate the reaction of other nucleophiles in the presence of a certain catalyst or oxidant.