Studies On The Synthesis Of Acetyl Flavones And Natural Polyhydroxy Biflavones

Total synthesis of bilobetin and isoginkgetin, natural polyhydroxy biflavones with a I-3'/II-8 dissymetrical connection, and synthesis of acetyl flavones were investigated in this dissertation. The details is as follows:1. Two synthetic routes were investigated, and acetyl flavones with acetyl substituted at different positions were synthesized by the route of p-propane-1,3-dione or condensation reaction at high temperature. It laid the foundation of synthesizing a series of new derivatives for future pharmacology research.2. Starting from phloroglucinol, synthesis of 8-iodo-flavones which are key precursors of bilobetin and isoginkgetin was accomplished by six steps of conversion. And analylogues of 3'-iodo-flavone, another kind of key precursors were prepared via esterification of respective hydroxyl benzophenones with 3-iodo-benzoic acid chlorides, Baker-Venkataraman rearrangement and cyclization.3. Several synthetic methods of aryl-aryl construction were probed for coupling of iodoflavones, and finally isopropyl protected target compounds were obtained by Palladium-catalyzed cross-coupling reaction (Suzuki reaction). After selective deprotection of isopropyl group, bilobetin and isoginkgetin were synthesized for the first time. Utilization of Suzuki reaction in the synthesis of biflavones was briefly investigated, the results indicated that steric factor appears to play an important role in the coupling progress of Suzuki reaction, the less steric hindrance of reacting materials is, the more favorable is the coupling reaction.4. Some of the synthesized compounds were tested for antitumor activity and the results showed that biflavone(45-3) and compounds21,22 have some antitumor activity. Additional pharmacology research work is still in progress.