The Research On The New Synthetic And Extractive Methods Of Flavonoids With Physiological Activity

Flavonoids are a kind of natural organic compounds with potential physiological activities and effective components of Chinese Herbs, which have attracted more and more research interest and exsist in nature extensively. The extraction, separation, idendification, synthesis and structure modification of the flavonoids are researched and three major parts are involved in this thesis.In first part the traditional Baker-Venkatarama rearragement synthetic method of flavones is reformed and the new synthetic method of flavones is achieved. In the new method the traditional esterification reaction and rearragement reaction are finished by one-step in alkaline medium. Three flavone compounds are synthesized from primary reactants of esterifiable hydroxybenzene by improved Baker-Venkatararaa rearragement method and five flavone derivatives are synthesized by modifying phenolic hydroxyl in A-ring. All of these synthesized flavone compounds are confirmed by IR, 1H NMR and MS techniques.The second part reports the successful "one-pot" synthesis of isoflavones conveniently instead of the traditional two-step synthetic methods of isoflavones. In the improved method DMF/PCl5 is used to C1 reagent and BF3/Et2O is used to solvent and catalyzer. Three isoflavone compounds are synthesized with hydroxybenzene and phenylacetic acid in the improved method and three isoflavone derivatives are synthesized by modifying phenolic hydroxyl in A-ring. All of these synthesized isoflavone compounds have been determined by means of MS, IR and 1HNMR spectroscopic methods.In the last part the new technics of extraction and isolation of Hesperidin from the orange peel is exploited with the application of ultrasonic reactor. The chemical investigation on the orange peel has led to the isolation of Hesperidin in higher yield rate from 1.44 percent to 2.32 percent and shorter reaction time from 3 hours to 30minutes,which is confirmed by IR and UV methods, The optimum extraction conditions are determined by orthogonal design method as follows: extraction temperature is 25, extraction time is 30 minutes,the rate of saturated Calcium hydroxide solution to orange peel in weight is 4:1, and the frequence of ultrasonic reactor is 25KHz. The average extraction rate of Herperidin and relative standard deviation(RSD) are 2.32% and 0.91% (n=3) respectively.