Total Synthesis Of Ochnaflavone And Its Derivatives

The thesis revolved around the total synthesis of natural productOchnaflavone and its derivatives, 6'-hydroxy-7-O-7'-dicoumarin and studieson antioxidative activities in vitro of different polarity fractions of extractfrom the aster.Chapter One Study on the the recent progress of biflavonoids.We reviewed the recent developments of the biflavonoids in detail.This kind of compounds possess extensive pharmacological actions. Thedeep researches on the relationship between their structure andpharmacological actions will provide theoretical basis for the newmedicines to cure many diseases. So, it is significant to investigate thesynthesis methods of biflavonoids and their derivatives.Chapter Two Studies on antioxidative activities in vitro of differentpolarity fractions of extract from the aster.In order to make full use of natural resources and provide scientificevidences for food and intensive processing, the extracts of the flowers andstems from the aster which were obtained via the solvent extraction processwere studied by the DPPH radical scavenging activity method. The resultsshow that all the active ingredients extracted by petroleum ether, EtOAc,acetone, ethanol and H2O exhibit good scavenging activity on DPPH radical.The free radical scavenging capacities of the extracts are significantlycorrelated to the aerosol mass concentration. The water extract has thehighest antioxidant activity.Chapter Three Total synthesis of Ochnaflavone and its derivativesAccording to the structural features of the target compounds,Ochnaflavone and its derivative were synthesized from m- t r i h ydr o x yb e n z eneand 4-Hydroxy benzaldehyde by the reaction of selective acylation,bromination, methoxymethylation, aldol condensation, ullmann reaction,cyclization, deprotection and so forth. The synthetic route is reasonable.However, this work is under way.Chapter Four Total synthesis of 6'-hydroxy-7-O-7'-dicoumarinThe recent developments on the pharmacological effects and clinical applications of the Coumarin and its derivates wre introduced briefly. Wedesigned a short practicable route to synthesize 6'-hydroxy-7-O-7'-dicoumarin from m-dihydroxybenzene, p-dihydroxybenzene and malonicacid through Reimer-Tieman reaction, protection of hydroxyl groups,reduction reaction, iodization, oxidizing reaction, ullmann reaction,deprotection, Knoevenagel reaction and reducing carboxyl. Compared withthe traditional methods, this method is more convenient due to milderconditions, shorter reaction time and higher yield.