Cyclization/Rearrangement Reaction Of α-Hydroxyketones Or α-Mercaptoketones With Trifluoromethyl N-Acylhydrazones

Heterocyclic compounds have always been widely studied in the field of organic chemistry,among which oxazoline is a very important five-membered heterocyclic compound.Currently,many compounds containing the oxazoline structure have been proven to have significant biological activity.This has led to the widespread application of oxazoline compounds in fields such as medicine,pesticides,total synthesis of natural products,and materials science.Therefore,many researchers have conducted extensive studies on the synthesis of oxazoline compounds,which are still ongoing.In order to further expand the application value of oxazoline,synthetic chemists have also attempted to introduce trifluoromethyl into the oxazoline skeleton.This is because the introduction of trifluoromethyl can significantly change the physicochemical properties and metabolic stability of the parent compound,thereby enhancing the efficacy of some drugs.In addition,trifluoromethyl also has unique electronic and steric effects,which often display different characteristics and rules from conventional organic reactions,making such reactions also have unique academic research value.Based on the above reasons,we designed and studied a method for efficiently preparing trifluoromethyl-substituted oxazoline derivatives through a cyclization reaction of trifluoromethyl N-Acylhydrazones as a trifluoromethyl source with α-hydroxy ketones under mild and practical conditions.It is worth mentioning that under this condition,the N-N bond cleavage of trifluoromethyl N-Acylhydrazones and the rearrangement of the amide segment are unprecedented in previous reactions.This provides a new idea for reactions involving trifluoromethyl N-Acylhydrazones.In addition,through this reaction,we obtained a series of trifluoromethyl oxazoline derivatives,some of which have enormous potential applications in the fields of medicine and pesticides.This chapter is composed of three parts as follows:Chapter 1: Research Progress on the Synthesis of Oxazoline CompoundsBased on literature review,this chapter summarizes the recent research progress on the synthesis of oxazoline compounds.Chapter 2: Ring-Closing/Rearrangement Reaction of α-Hydroxy Ketones with Trifluoromethyl Acyl AzideThis chapter mainly explores the cyclization /rearrangement reaction of α-hydroxy ketones with trifluoromethyl N-Acylhydrazones.Under acidic conditions,the N-N bond cleavage and acyl amide rearrangement of trifluoromethyl N-Acylhydrazones are unprecedented in previous reactions.This provides a new direction for reactions involving trifluoromethyl azides.In addition,this reaction provides a series of trifluoromethyl oxazoline derivatives,which have great potential applications in the fields of medicine and pesticides.Chapter 3: Ring-Closing Reaction of α-Thio Ketones with Trifluoromethyl Acyl AzideThis chapter explores the synthesis of fluorinated thiazole compounds through the ring-closing reaction of α-thio ketones with trifluoromethyl N-Acylhydrazones under acidic conditions.This reaction features of simple operation,easy access to raw materials,no catalyst,mild conditions,high atomic economy,and step economy.