Structural Modification And Activity Of Natural Products Such As Paeonol Based On Iridium Catalyzed Hydrogen Transfer Reaction

Objective:A series of target compounds were synthesized by structural modification of natural products such as paeonol through hydrogen transfer reaction catalyzed by iridium metal.The antibacterial activity and antioxidant activity of the synthesized target compounds were tested in vitro,with a view to screening out compounds with better activity than paeonol.Methods:Using selected raw materials as substrate templates,the types of catalysts,bases,solvents,temperatures,and other conditions were screened to select the optimal reaction conditions.The functional group types and positions of the reaction substrate were expanded to verify their broad-spectrum properties.The synthesized compounds were subjected to ¹H NMR,¹³C NMR,and HRMS-ESI to determine their structure.The scavenging ability of target compounds 3aa-3al series,5aa-5ak series,and8aa-8ea series on free radicals was measured using the DPPH method,and the antioxidant activity of the synthesized target compounds was preliminarily evaluated.At the same time,he microdilution method was used to test the antibacterial effect of paeonol derivatives,cinnamyl alcohol derivatives,quinoline derivatives and other major strains of Escherichia coli,Staphylococcus aureus,Candida albicans in vitro.Results:The DPPH free radical scavenging experiment results of the target compound showed that 26 compounds had a better scavenging effect than the parent compound paeonol,with compound 6aa having a better scavenging effect than the standard vitamin C.In vitro antibacterial activity test results showed that cinnamyl alcohol derivative 12ka（MIC value of 16μg/m L）,12la and quinoline derivatives 14ab,14ad（MIC value of 2μg/m L）,14ah,14ai,14aj,14bj,14ak,14ck,14an and other compounds have better antibacterial activity in superior the parent drug norfloxacin.Conclusion:The analysis of the above experimental results founds that the structural modification of natural products such as paeonol based on iridium catalyzed hydrogen transfer reaction can effectively improve the antioxidant capacity of natural products.In these transformation processes,the problems of low bioavailability of natural products such as paeonol have been solved to a certain extent,providing theoretical and practical basis for the structural transformation of natural products such as paeonol.