Pdlladium-Catalyzed Tandem Cycloaddition Of O-Aminobenzoic Acids,Amines,CO And Aldehydes For The Synthesis Of N-Substituted-2,3-Dihydroquinazolin-4（1H）-Ones

N-substituted-2,3-dihydroquinazolin-4（1H）-ones,a class of nitrogen-containing heterocyclic compounds,have good biological and pharmacological activities such as anti-inflammatory,anti-cancer,antibacterial,anti-infective,and anti-malarial,etc.So they have a very wide range of applications in the fields of pharmacy and medicine.Therefore,synthetic methods to obtain a large number and diversity of these compounds have been a hot topic of interest for organic chemists.A variety of high yield synthesis methods have been reported for these substances,but they all have major drawbacks,such as harsh reaction conditions,high raw material cost,overly complex raw material structure,poor atomic economy,hard-to-get catalysts,many reaction steps and long reaction time,complicated post-treatment,and large environmental pollution.To address these drawbacks,this paper proposed a one-pot way,using easy-to-obtain o-aminobenzoic acid,CO,amines and aldehydes as substrates,to synthesize N-substituted-2,3-dihydroquinazolin-4（1H）-ones via a tandem cycloaddition reaction under the catalysis of palladium acetate.This method has the advantages of simple synthesis route,mild reaction conditions,high atom economy,low cost,environmental protection and so on.This article is divided into two chapters:Chapter one,literature review.There are mainly five aspects in this chapter:（1）Important applications of N-substituted-2,3-dihydroquinazolin-4（1H）-ones.（2）The main synthesis methods of N-substituted-2,3-dihydroquinazolin-4（1H）-ones.（3）The important role of palladium catalysis in carbonylation reactions.（4）Tandem reactions and their advantages.（5）The topic selection and conception of the thesis.Chapter two,study on the synthesis of N-substituted-2,3-dihydroquinazolin-4（1H）-one.In this chapter,palladium acetate is used as a catalyst to catalyze the one-pot synthesis of N-substituted-2,3-dihydroquinazolin-4（1H）-ones through the tandem cycloaddition carbonylation reaction of o-aminobenzoic acid with amine,CO and aldehyde.At the same time,different conditions such as the type of catalyst,the type of additives,the type of oxidant,the type of solvent,the reaction temperature,the reaction time,and the amount of added drugs have been optimized and screened.Based on the optimized reaction conditions,the applicability of the substrate expansion was explored,and a series of N-substituted-2,3-dihydroquinazolin-4（1H）-ones derivatives were obtained.Finally,on the basis of the reported literature,combined with the control experiment,a possible reaction mechanism of palladium-catalyzed o-aminobenzoic acid with amine,CO and aldehyde tandem cycloaddition reaction to synthesize N-substituted-2,3-dihydroquinazolin-4（1H）-ones was proposed.