Study On Total Synthesis Of Two Natural Benzopranylchalcones And Five Geranylated Flavonoids

In this work, the total synthesis of 7 natural products were finished, involved the preparation of 33 compounds. Their structure was established by the analysis of their spectral data. Chapter I: ReviewNaturally occurring 94 benzopranylchalcones were reviewed on their distribution in plants, characterization of structure, total syntheses and pharmacological activities. References 85. Chapter II: The study on total synthesis of two natural benzopranylchalconesTwo natural benzopranylchalcones 5-hydroxyl-7-methoxyl-6-[2-m-ethyl-2-(4'-methyI-3'-prenyl)-bihydroyl-l-benzopranyl]chalcone (2-1) and 7-hydroxyl-5-methoxyl-8-[2-methyl-2-(4'-methyl-3'-prenyl)-bi-hydroyl-l-benzopranyl]chalcone (2-2), have been synthesized in four steps staring from 1,3,5-trihydroxylphenol and citral, their yield were 21% and 8% respectively. A series of chalcones, flavonoids and flavanones with Methyl, methoxyl and isoprenyl can be synthesized by this route.Chapter III: The study on total synthesis of five natural geranylated flavonoidsFive natural geranylated flavonoids, three geranylated chalcones:2'-geranyl-3,4,4'-trimethoxyl-2'-hydroxylchalcone(3-12),2,2'-bigeran-yl-3,4,4'-trimethoxyl-2'-hydroxylchalcone(3-13) and 2-geranyl-3,4,4'-trimethoxyl-2'-hydroxylchalcone(3-19b), and two geranylated flavano-nes:3'-geranyl-5, 7,2', 4'-tetramethoxylflavanone(3-20a), 2'-geranyl-5,7,3',4'-tetramethoxylflavanone(3-20c), have been synthesized staring from 1,3,5-trihydroxylphenol, 1,3-bihydroxylphenol, 3,4-bi-hydroxylbenzophenone, 2,4-bihydroxylbenzophenone and geraniol. The synthesis methods of chalcone and benzene ring alkylation are discussed.