The Studies On Synthesis And Activities Of Quercetin Derivatives

Flavonoids are widely distributed in nature, and quercetin is an importantmember of them, which have great medicinal value. Quercetin has extensivepharmacological effects and biological activities, such as anti-oxidant, anti-tumor,anti-virus, anti-blood platelet, anti-arrhythmia and so on. Therefore, the studies onsynthesis and activities of quercetin derivatives have been attracted more attention.In this paper,3’,4’,7-tri (-O-ethoxyl-) quercetin (THQ) was successfullysynthesized through etherification and hydrolysis from rutin, and20quercetinderivatives were successfully synthesized through alkylation from THQ, including18new compounds. Their structures were fully characterized by1H-NMR,13C-NMR,IR, HR-MS and UV-Vis spectroscopies. Additionally, the antioxidant activities ofpart of the compounds were tested by means of improved pyrogallol autoxidationmethod. The surface tensions of part of the compounds were measured by theWilhelmy plate method. This thesis consists of five parts. And the solubility in waterof one compound was measured by equilibrium method. The main content of thethesis is as follow:1. The classification and the research progress in synthesis of flavonoids werereviewed, and the synthesis of quercetin amino acids, esters, glycosides, ethers,carboxylic acids derivatives and metal complexes as well as the current status of studyon the biological activities of those derivatives are briefed.2. THQ was successfully synthesized through etherification and hydrolysis fromrutin. Then THQ-3-O-ethyl acetate was synthesized through alkylation from THQ.THQ-3-O-sodium acetate and THQ-3-O-potassium acetate were successfully synthes-ized through hydrolysis from THQ-3-O-ethyl acetate, and THQ-3-O-acetic acid wassynth-esized through acidification. Their structures were characterized by1H-NMR,13C-NMR, IR, HR-MS and UV-Vis spectroscopies. The antioxidant activities of quercetin and the two THQ-3-O-acetate derivatives were determined by means ofimproved pyrogallol autoxidation method. The free radical scavenging abilities werecalculated. The surface tensions of the two THQ-3-O-α-acetate derivatives solutionswere measured by the wilhelmy plate method. And the solubility in water of theTHQ-O-sodium acetate was measured by equilibrium method.3. THQ was successfully synthesized through etherification and hydrolysis fromrutin. Then THQ-3-O-α-methyl propionate, THQ-3-O-α-ethyl propionate, THQ-3-O-α-propyl propionate, THQ-3-O-α-propyl propionate, THQ-3-O-α-isopropyl propiona-te, THQ-3-O-α-n-butyl propionate were synthesized through alkylation from THQ.THQ-3-O-α-sodium propionate and THQ-3-O-α-potassium propionate were synthesi-zed through hydrolysis from quercetin ester derivatives, and THQ-3-O-α-propionateacid was synthesized through acidification. Their structures were characterized by1H-NMR,13C-NMR, IR, HR-MS and UV-Vis spectroscopies. The antioxidant activiti-es of quercetin and the two THQ-3-O-α-propionate derivatives were determined bymeans of improved pyrogallol autoxidation method. The free radical scavengingabilities were calculated. The surface tensions of the two THQ-3-O-α-propionatederivatives solutions were measured by the wilhelmy plate method.4. THQ was successfully synthesized through etherification and hydrolysis fromrutin. Then THQ-3-O-α-methyl butyrate, THQ-3-O-α-ethyl butyrate, THQ-3-O-α-pro-pyl butyrate, THQ-3-O-α-propyl butyrate, THQ-3-O-α-isopropyl butyrate, THQ-3-O-α-n-butyl butyrate were synthesized through alkylation from THQ. THQ-3-O-α-sodiu-m butyrate and THQ-3-O-α-potassium butyrate were synthesized through hydrolysisfrom quercetin ester derivatives, and THQ-3-O-α-butyrate acid was synthesizedthrough acidification. Their structures were characterized by1H-NMR,13C-NMR, IR,HR-MS and UV-Vis spectroscopies. The antioxidant activities of quercetin and thetwo THQ-3-O-α-butyrate derivatives were determined by means of improved pyrogal-lol autoxidation method. The free radical scavenging abilities were calculated. Thesurface tensions of the two THQ-3-O-α-butyrate derivatives solutions were measuredby the wilhelmy plate method.5. Conclusion.