The Studies On Synthesis And Application Of Quercetin Derivatives

Quercetin is an important member of the polyphenolic flavonoid compounds, andbelongs to flavonol compounds. It exists mostly in the form of indicans in plants.Quercetin and its derivatives have lots of pharmacological activities, for example,anti-arrhythmia, anti-blood platelet, antioxidant, anti-cancer agent, and blood-vessel-expanding and so on. The studies on synthesis and pharmacological activities ofquercetin and its derivatives have been attracted more attention。In this paper, the structure of quercetin was modified. 11 quercetin derivativeswere successfully synthesized and have never been reported. Their structures werefully characterized by1H NMR,13C NMR and IR spectroscopies. Fluorescence systemof 3′,4′,7-tri(-O-ethoxyl-)quercetin-Fe(Ⅲ) was examined, and it can be used to detectthe content of ferrous sulfate in ferroids by fluorospectrophotometry. The articleconsists of five parts. The detailed structure of the thesis is listed as follow:1. The recent research progress was showed in this article, including synthesis ofquercetin derivatives, pharmacological activities of quercetin and its derivatives andapplication of quercetin metal complexes through fluorospectrophotometry.2. 3′,4′,7-Tri(-O-ethoxyl-)quercetin respectively reacted with benzyl chloride,1-bromododecane and n-hexadecyl bromide. Three monoalkylated ethers derivatives ofquercetin were synthesized, and their sutructures were characterized by1H NMR,13CNMR and IR spectroscopies. These compounds have not been reported so far.3. Troxerutine as the starting material reacted with acetic anhydride underconcentrated sulfuric acid as the catalyst. 2 ester derivatives of quercetin weresynthesized. Their structures were characterized by1H NMR,13C NMR and IRspectroscopies. These compounds have never been reported.4. 3′,4′,7-Tri(-O-ethoxyl-)quercetin respectively reacted with ethyl bromoacetateand methyl chloroacetate. 2 new intermediates were gained, and one carboxylic acidderivative of quercetin was synthesized through hydrolysis reactions of these intermediates. Then it respectively reacted with CdI2, CaCl2and BaCl2to get threecarboxylates. Their structures were characterized by1H NMR,13C NMR and IRspectroscopies. These compounds have never been reported.5. Fluorescence system of 3′,4′,7-tri(-O-ethoxyl-)quercetin-Fe(Ⅲ) was examinedand it could be used to detect the content of ferrous sulfate in ferroids byfluorospectro- photometry. This method is very convenient with the high sensitivity. Itcan provid a significant basis for content determination of iron in drugs.