The Construction Of Oxazoles And Benzoxazine Derivatives Via Arylglyoxal-Involved Multicomponent Tandem Cyclizations

Heterocyclic compounds are the largest group of organic compounds,which were widely found in bioactive molecules,drug molecules,natural products and functional materials etc.Among them,N,O-heterocyclic compounds often exhibit unique physiological activities due to the presence of both nitrogen and oxygen.The main N,O-heterocyclic compounds are 5-membered oxazoles and 6-membered oxazines,which also play an important role in the fields of medicine and materials.The synthesis of these two types of N,O-heterocyclic compounds have always been favored by chemical workersIn this paper,we chose N,O-heterocyclic compounds,which were potentially pharmacological active and valuable in functional materials,as a basic research skeleton,and mainly studied fully substituted oxazoles and 3,1-benzoxazine derivatives.Arylglyoxals are used as the core building blocks to design and synthesize two kinds of target molecules using the reaction strategy of multi-component tandem cyclization.The main contents of this paper include the following three parts:The chapter 1,we summarized arylglyoxals as synthetic buiding blocks to synthesize N,O-heterocyclic compounds and the synthesis of fully substituted oxazoles and 3,1-benzoxazine derivatives in recent years.On the basis of this,we proposed the research topic of this paper.The chapter 2,based on our previous study to arylglyoxals and the awareness of fully substituted oxazole compounds,we studied trifluoroacetic acid-promoted multicomponent tandem cyclization reaction to synthesize diversified fully substituted oxazoles from arylglyoxals with different carbon nucleophiles(4-hydroxycoumarin,2-naphthol,1,3-cyclohexadione)in one pot in acetonitrile via Robinson-Gabriel strategy.Through the control experiment and a series of related literatures,the possible reaction mechanism was proposed for this reaction.The chapter 3,based on the previous research on 2-aminobenzyl alcohol and the awareness of 3,1-benzoxazine derivatives,we studied arylglyoxals and 2-aminobenzyl alcohol as reaction substrate,through the integration of many organic unit reactions such as nucleophilic addition and intramolecular hetero-cyclization.They were integrated in one pot under acidic conditions and the direct synthesis of multiple fused ring double 3,1-benzoxazine derivatives was achieved.This skeleton is synthesized for the first time,and we realizes the construction of three consecutive rings and the formation of six bonds.