Studies On The Synthesis Of Nitrogenous Base And Prenyl Ether Of Flavones

The natural flavonoids which is a main component of many medicinal plants is a kind of important natural organic compound, So far, more than six thousand flavonoida are identified. The natural product hesperidin, widely exists in sweet orange or biggarade have exhibited significant biological activities such as inhibition of cardiovascular dieases and inhibit the excitement in nerve centre. Because of its low water solubility and poor lipophilicity, it cannot be absorbed when used directly for drugs, which limit its application in medicine and health food fields. So the semisynthesising of higher biological compounds through modifications of hesperidin which utilize resources rationally, have a advantage of its simple procedure,plentiful convenient and loe cost. As one of the members of the family of flavonoids, chalcones widely exist in the root, branch and peel of medicinal plants. Owing to their special chemical structure, they have many important physiological functions in mammals such as antineoplastic, antiviral, antibiosis, and antioxygenation. At the moment, many chalcone derivatives are used in clinic. The thesis aims at the studies on the semisynthesis of flavanone and flavanone derivative new from hesperidin and naringin. The thesis with the rich resource of natural flavonoids of hesperidin as raw materials, respectively through Mannich reaction and the1,3-dipolar cycloaddition synthesized compounds4a-4e,7c,11,12,15.1.2’-hydroxy-3,4,4,6-4-methoxy chalcones was synthesized from hesperidin and based on the hydrolyzation of hesperidin, selective methylation and open loop. Five new Mannich base derivatives were synthesized through Mannich action, and the regioselectivity of this reaction preferentially occurred at C-3posiontion of B ring of the backbone, at last, an aminomethyl was brought to the backbone chalcone. Series Manncih base derivatives4a-4e was synthesized.2. The synthesis of (7-O-benzyldiosmetin) is finished based on the dehydrogenation, benzyl protection of phenol hydroxyl, hydrolyzation of hesperidin. Based on the method of "Click chemistry", and the revised phase-tranfer catalysis method, intermolecular Cu (I) catalyzed3’-O-benzyldiosmetin,3-dipolar cycloaddition of the alkynes of and corresponding glycosyl azides is the critical step. During the reaction, the manipulation of step-by-step feeding can prevent the ether-acetylene bond cleavage, simplify the processing steps, and increased the yields of the reaction to80%. Under the hydrogen gas protection, the benzyl group was took off by using Pd/C catalyst and the compound7b was composed. In the last place, methanol-sodium alcohol system was used to take off the acetyl, the compound7c was composed.3. The synthesis of7-O-methylapigenin13and7-O-benzylapigenin10was synthesized from naringin and based on the dehydrogenation, methyl protection and phenol hydroxyl, hydrolyzation. Then it is treated with prenyl bromide and anhydrous potassium carbonate in anhydrous acetone, to effect etherification and produced two new compound. In addition to this, a new Mannich base derivatives were synthesized through Mannichacton, and the regioselectivity of this reaction preferentially occurred at C-8posiontion of B ring of the backbone, at last, an aminomethyl was brought to the backbone.4. Herein, The synthesis of a series of derivative flavonoids derivatives are not reported literatures. The structures of the synthesized compounds have been confirmed by1H NMR, MS and IR.