Synthesis Of ?-Trifluoromethylated Homoallylic Hydrazides And Oxime Esters

In recent years,organic fluorine chemistry has been a rapidly developing discipline.With the development of organic fluorine chemistry,fluorine-containing organic compounds are widely used in new materials,pesticides,and pharmaceutical fields.Trifluoromethyl-containing compounds occupy a pivotal position in thefield of fluorine chemistrydue to the introduction of the trifluoromethyl group into drug molecules can significantly enhance the biological activity,lipophilicity,and metabolic stability of the drug molecules.Therefore,how to construct compounds containing trifluoromethyl group arouse extensive attention and research in the field of chemistry.Up to now,there are two main methods for introducing trifluoromethyl groups into organic compounds: one is direct trifluoromethylation and the other is the use of trifluoromethyl building blocks.The second method is to construct trifluoromethyl group-containing compounds through a series of chemical transformations using fluorine-containing organic small molecules as building blocks.The trifluoromethyl-containing organic small molecules are often a class of industrially available,stable and diverse compounds,which make the reaction has advantages of simple operation and good synthesis efficiency.Therefore,the synthesis of trifluoromethylated compounds from trifluoromethyl building blocks has been widely developed in the chemical industry,which has shown broad application prospects.In this paper,we synthesized trifluoromethylated homoallylic hydrazides and trifluoromethylated oxime ester compounds by using two different trifluoromethyl acylhydrazone as trifluoromethyl building blocks.This paper is divided into three chapters: Chapter 1: Progress in the application of trifluoromethyl building blocks in the synthesis of organic compounds containing trifluoromethyl groupsIn this chapter,we mainly introduced all kinds of trifluoromethyl building blocks,such as trifluoroacetaldehydes,trifluoropyruvates,trifluoromethylimines,trifluoromethyl olefins,ethyl trifluoroacetoacetates and its derivatives and so on,and progress in the application of trifluoromethyl building blocks in the synthesis of organic compounds containing trifluoromethyl groups was reviewed.Chapter two: Tin powder promoted synthesis of ?-trifluoromethyl homoallylic hydrazidesIn this chapter,we synthesized an ester group-containing trifluoromethyl acylhydrazone from ethyl trifluoromethylpyruvate and hydrazide.We used the trifluoromethyl acylhydrazone as a new trifluoromethyl building block to develop a convenient protocol for the synthesis of functionalized ?-trifluoromethyl homoallylichydrazides by tin powder-promoted one-pot allylation reaction.A series of ?-trifluoromethyl homoallylic hydrazides containing a quaternary carbon center were synthesized in good yields by using ethyl trifluoromethylpyruvate as trifluoromethyl building block.Chapter three: Study on the reaction of trifluoromethyl acylhydrazones with N-hydroxybenzimidoyl chloride: synthesis of trifluoromethyl oxime estersIn this chapter,trifluoromethyl acylhydrazones were used as trifluoromethyl building blocks.Under the combined action of mixed base and Lewis acid,we studied the synthesis of trifluoromethyl oxime esters by the reaction of trifluoromethyl acylhydrazones with N-hydroxybenzimidoyl chlorides.The method has following characteristics: mild reaction conditions and good yields,which provides a new synthetic method for trifluoromethyl oxime esters.