Studies On The Synthesis And Properties Of Some Lfavonoids

Flavonoids has four structural frames includes chalcone, flavone, isoflavones andflavanones. Distinct in its construct, flavonoids are particularly biologically active inantioxidant, antibacterial, antiviral, anti tumor, anti allergy, regulation of the immune,cardiovascular, endocrine and etc. Due to the enormous enthusiasm invested bygroups of researchers, there exist numerous reports on how to create chalcone andflavanone. However, efforts are still needed to further improve the biological activityof those compounds. Therefore, inventing new organic synthesis methods, structuralmodification and optimization and searching specific lead compounds are of essentialimportance.In2010, our group have reported a new method of synthesis of natural productslicorice chalcones E in synlett, Compared to previous reports; our method is relativelysimple and more productive. Also it is found in our work that licorice chalcone ketoneE is more biologically active than licorice chalcone ketone A and it has moresignificant inhibition to staphylococcus aureus. Inspired by this result and trying tooptimize its structure, a series of new chalcone and flavanone are synthesized, withtheir properties carefully studied.There are three chapters in this dissertation, the first one outlines the concept,classification, extraction of flavonoids and their application, and focused on thephysiological activities of the flavonoids and the synthesis methods of chalcone andflavanone compounds.The second chapter is the synthesis part of this thesis, according to the literaturereported by predecessors, we have designed and explored a synthetic route, andeventually a series of new chalcone and flavanone compounds have been gained.3methoxy4hydroxybenzaldehyde （or2methoxy4hydroxybenzaldehyde） asthe starting material, reacts with prenyl bromide, and then the important intermediateis obtained by the abnormal Claisen rearrangement, the compound is.3methoxy4hydroxy5（3methylbut3en2yl）benzaldehyde（or.2methoxy4hydroxy5（3methylbut3en2yl）benzaldehyde）, and finally under HCl conditions, intermediates andhydroxyacetophenone as the starting material, the corresponding chalcone compoundsis obtained via Claisen Schmidt Condensation.2,4hydroxyacetophenone and 2,4,6Trihydroxyacetophenone need chloromethyl ether protection, respectively, theprotection of2hydroxy and2,6hydroxy （abnormal Claisen rearrangement for a4hydroxyl also need chloromethyl ether protection）, then under NaOH conditions, bythe Claisen Schmidt condensation reaction, get the corresponding with MOMprotecting groups chalcone, the corresponding chalcone compounds is obtained ifdirect hydrolysis, the corresponding flavanone compounds is obtained if on weaklybasic NaOAc catalyzed cyclization and finally hydrolysis. All the intermediatecompounds are confirmed by¹H NMR and the structures of the final products are alsoconfirmed by¹H NMR,¹³C NMR, MS and melting point.The third chapter is test, and mainly test for the oxidation resistance andanti Staphylococcus aureus of the new chalcone and flavanone compoundssynthetized by second part of this paper, some laws about the relationship betweenactivity and group structure have been found by compared analysis, which provides areference value for the follow up studies in medicine of chalcone and flavanone.