Allylation And Cyclization Reactions Of Trifluoromethyl Acylhydrazones

In recent years,as a stable imine substitute,acylhydrazones has received more and more attention in organic synthesis.It can react with many nucleophiles to form various nitrogen-containing compounds.Common reactions of acylhydrazones include reduction reaction,Mannich reaction,allylation reaction,cyanation reaction and cycloaddition reaction,and free radical reaction,etc.,which generate various nitrogen-containing compounds.On the other hand,trifluoromethyl group is a common fluorine-containing group.Introduction trifluoromethyl group into a compound molecule can significantly change the acidity and basicity,lipophilicity,and metabolic stability of the compound.Therefore,trifluoromethyl-containing compounds are widely used in the fields of medicine,pesticides and materials science.Among the many methods for synthesizing trifluoromethyl compounds,the trifluoromethyl synthesis block method is a common and simple method.In this thesis,we use trifluoromethyl acylhydrazones as building blocks,which is stable to water and air,and easy to prepare,to synthesize a series of trifluoromethylated homoallyl hydrazides and pyrazoline compounds through the allylation and cyclization reactions of trifluoromethyl acylhydrazones.The thesis consists of the following four parts:The chapter one: Research Progress of Allylation and Cyclization Reactions of AcylhydrazonesThis chapter mainly introduces the research progress of allylation and cyclization reactions of acylhydrazones.It mainly introduces research progress of the allylation reaction and cyclization reaction of acylhydrazones with carbon-carbon double bonds,carbon-carbon triple bonds,and carbon-nitrogen triple bonds.The chapter two: Study on the Allylation of Trifluoromethyl Acylhydrazones with Allyl Silicons or Allyl BoronsThis chapter explores the allylation reaction of trifluoromethyl acylhydrazones with allyltrimethylsilane or allylboronic acid pinacol ester,and a series of trifluoromethyl substituted homoallyl hydrazides is obtained in high yields.The reaction has the advantages of mild reaction conditions,simple operation and high yields.The results showed that the activity of allylboronic acid pinacol ester washigher than that of allyltrimethylsilane.At the same time,the method further expands the application range of trifluoromethyl acylhydrazones as a trifluoromethyl building block in trifluoromethylation reactions.The chapter three: Study on the Cascade Allylation/Cyclization/Halogenation of Trifluoromethyl Acylhydrazone with Allyl Silicon ReagentIn this chapter,we used NXS as a halogenating reagent to achieve a three-component “one-pot” cascade allylation/cyclization/halogenation reaction of trifluoromethyl acylhydrazones and allyltrichlorosilane.trifluoromethyl pyrazoline compounds were synthesized in good yields.The method has the advantages of mild reaction conditions,no metal catalysis,simple operation and high yields.The chapter four: Study on the Addition and Cyclization of Trifluoromethylhydrazone with MalonitrileIn this chapter we have developed a cycloaddition reaction of trifluoromethyl acylhydrazones with malononitrile to synthesize 5-amino-1-benzoyl-3-(trifluoromethyl)-2,3-dihydro-pyrazoline-4-carbonitriles.The method has the advantages of mild reaction conditions,simple operation and high yields.The products can be further converted into pyrazole compounds with potential application value.