Synthesis And Properties Of Coumarin Biologically Active Substance

The transformation and the modification of natural compounds are important ways and means to discover new medicines.Coumarin is a common structural unit of active natural products.It is not only widely found in nature,but also existsmany of the traditional Chinese herbal medicine in the active ingredients,such as Cnidium,Heracleumhemsleyanum,Angelica,Cortexi and other Chinese herbal medicine that contains coumarin derivatives.A large number of studies show that coumarin compoundsare significant biological active substances with small molecular weight,changeable structure,simple synthesis,special mechanism,high bioavailability,wide pharmacological effects and low toxicity characteristics.Therefore,they often used as intermediates and drugsin the pharmaceutical industry.Because many coumarins content in plants are low,rare distribution and limited resources,total synthesis of the natural coumarins and its derivative modified synthesis has been an active research direction.In order to make total useing of coumarin compounds,our research is basis of coumarin compounds,through modification and transformation of its structure,to obtain a large number of compounds with potential biological activity for performance testing.Simultaneously,the study is to explorenew bioactive lead compounds with fascinating prospects.So that this study has important purposes which are helping develop new medicines and drugs.At the same time,coumarin compounds with excellent optical properties,can be used as metal ion fluorescent probe and nonlinear optical materials.Through the synthesis of coumarin derivatives and the screening of fluorescent properties,to find a cationic fluorescent probe with excellent performance.It is expected that it can be applied to the fields of biochemistry,medicine,environmental science and molecular biology.In this paper,the research progress of coumarin compounds was reviewed in recent years.Twelve coumarin derivatives were designed and synthesized from economy 2,3,4-trimethoxybenzaldehyde as raw materials.Then their antioxidant activities were evaluated by in vitro chemical methods and the fluorescence properties of some derivatives were studied.The main work of this paper is as follows:1.In this paper,the recent advances of coumarin compounds were reviewed,especially the study on the antioxidant properties of coumarin compounds and the progress in the study of fluorescent probes.2.Based on the simple to get easy 2,3,4-trimethoxybenzaldehyde as raw materials,five novel coumarin-containing aromatic amide derivatives and six Schiff base coumarin derivativeswere synthesized by reduction,Knoevenagel and acylation.These coumarin derivatives have not been reported in the literature,and their structures were characterized by NMR,MS,IR and other spectroscopic methods.3.The synthesis process of the key intermediate coumarin parent ring is studied,and the optimized synthetic route has the characteristics of simple operation,low time consumption and high yield.Through a single factor study of the experiment,the optimum conditions of the reaction were found as follows: acetic anhydride and DMF(volume ratio 1:3)as solvent;n(aldehyde): n(acid):n(catalyst)=1:1.4:0.6;the reaction temperature of 150? and reaction time of 3 h,the yield reached 77.9%.It is for the synthesis of the target product to provide raw materials.The optimized synthesis route is simple,time-consuming and high-yield.4.The antioxidant properties of the two series of coumarin derivatives were tested by DPPH radical scavenging ability,ABTS radical cation scavenging ability and hydroxyl radical scavenging ability respectively.The results showed that partial of compounds showed antioxidant activity.Among them,the compounds 5b,6f,6d and 6eexhibit better or comparable free radical scavenging ability compared to the control.Compared with the compound 4,more than 50% of the derivatives showed good antioxidant activity.It indicated that the derivatization of the compound 4 is advantageous for the antioxidant activity,particularly in the Schiff base coumarin derivative.The compound 6f(7,8-dimethyl-3-(4'-hydroxy-3'-methoxy)coumarin showed the highest free radical scavenging ability in all free radical test.It has good antioxidant properties and the value of further research.5.The fluorescence performance of a series of Schiff base coumarins was tested.It was found that compound 6a had fluorescence properties by selective identification of metal ions.However,when the presence of metal ions Zn2+,the fluorescence enhancement of 7.74 times.This result indicated that the compound is very sensitive to metal ions Zn2+,and interference of other metal ions on the Zn2+ is very small.It showed there is a good selectivity and potential probe of zinc ion.What's more,compound 6f has a good selectivity for Ni2+and its fluorescence enhancement is 6.94 times,which is possible as a nickel ion probe.It is found that the coordination ratio of 6a and 6fto metal ions is 1:1 by Job-plot method.We believe fluorescent probes 6a and 6f have potential application value in organisms,environmental monitoring and supramolecular luminescent materials.