Research On The Synthesis And Antibacterial Activity Of Aromatic Heterocyclic Functional Molecules Based On NHC Catalysis

2-pyrone compounds are widely found in natureand nitrogen-containing heterocyclic compounds are among the more widely distributed.Its' unique biological activities(such as: antibacterial,anti-virus,etc.)have received great attention from researchers.How to make use of cheap and readily available raw materials,under the mild reaction conditions,efficient synthesis of 2-pyrone compounds is a research hotspot in recent years.Small molecule catalysts are the focus of research and attention of organic synthetic chemists in recent years.As an important member of the organic small molecule catalysts,N-heterocyclic carbenes(Abbreviated as NHC)have unique advantages in catalyzing the activation of carbonyl compounds.Cinnamaldehyde is one of the most commonly used active carbonyl compounds catalyzed by NHC.At present,the reaction of aldehydes or active esters with various nucleophiles and electrophiles catalyzed by NHC has been widely studied.However,the reaction of NHC-catalyzed aldehydes or active esters with pyridine ylide has rarely been reported.Therefore,this dissertation mainly focuses on viaing carbine catalyzed oxidative [3 + 3] reactions between enals and pyridinium ylides to rapid construction of 2,6-disubstituted 2-pyridones and their biological activities.1.Under the action of NHC catalyst and biphenyl dioxime oxidant,catalytic oxidation of enal aldehydes to form unsaturated acylpyrazole intermediates,[3+3] cycloaddition reaction with ketocarbonyl ylide,one-step concise and efficient construction 2,6-Disubstituted-2-pyrones,partial substrates can achieve isolated yields greater than 90%.2.The antibacterial activity of 200 ?g/m L against Xanthomonas oryzae?pv.oryzae were tested on the synthesized target compounds by the turbidimetric method.The results showed that the antibacterial activity of 2,6-disubstituted-pyrone compounds on these two plant bacteria are general.