Structural Studies of Tetranortriterpenoids from the Congolese species of Entandrophragma angolense And Efficient Short Step Synthesis of Corey’s Tamiflu Intermediate

理工学研究科博士論文(理学) ; 学位取得日: 平成20年3月25日This dissertation comprises two parts, one is the chemistry of natural products dealing with the isolation and structure elucidation of limonoids and the second part is synthetic organic chemistry dealing with the use of a stereoselective based-catalyzed Diels-Alder reaction for the synthesis of small biologically active compound ingredient. Structural Studies of Tetranortriterpenoids from the Congolese species of Entandrophragma angolense The extracts of E. angolense, a Meliaceae plant used in African folk medicine against malaria, displayed considerable antifeedant activity against Spodotera insects. Thus, the plant was selected for further fractionation of its extracts. The fractionation of the extracts has been carried out using chromatographic methods and resulted to the isolation of twenty-three compounds. The structure elucidation of these compounds was performed by spectroscopic methods including mass spectrometry, 1D and 2D NMR. Two compounds are not limonoids and the remaining ones are limonoids and could be classified as protolimonoid, gedunin, andirobin and phragmalin compound-types. Sixteen compounds have been found to be new rings and the five known compounds isolated have been identified as methyl angolensante, methyl 6-acetoxyangolensante, secomahoganin, 3β-hydroxy-3-deoxycarapin and xyloccensin K. Efficient Short Step Synthesis of Corey’s Tamiflu Intermediate Catalysts have been used to facilitate the Diels-Alder reaction and almost catalysts developed are Lewis acids. Our lab developed a unique base-catalyzed diastereoselective Diels-Alder reaction of pyridone derivative as diene and electron deficient dienophiles. The unique poly-functionalized bicyclolactam obtained from the reaction between N-nosyl-3-hydroxy-2-pyridone and ethyl acrylate has been used as building block for the synthesis of Corey’s Tamiflu intermediate. This synthesis route is short and the production of different intermediates is simple. Only four chemical transformations and three purification steps are required to obtain the targeted compound, equivalent to the Tamiflu intermediate from the Diels-Alder adduct.鹿児島大

Structural Studies of Tetranortriterpenoids from the Congolese species of Entandrophragma angolense And Efficient Short Step Synthesis of Corey’s Tamiflu Intermediate

理工学研究科博士論文(理学) ; 学位取得日: 平成20年3月25日This dissertation comprises two parts, one is the chemistry of natural products dealing with the isolation and structure elucidation of limonoids and the second part is synthetic organic chemistry dealing with the use of a stereoselective based-catalyzed Diels-Alder reaction for the synthesis of small biologically active compound ingredient. Structural Studies of Tetranortriterpenoids from the Congolese species of Entandrophragma angolense The extracts of E. angolense, a Meliaceae plant used in African folk medicine against malaria, displayed considerable antifeedant activity against Spodotera insects. Thus, the plant was selected for further fractionation of its extracts. The fractionation of the extracts has been carried out using chromatographic methods and resulted to the isolation of twenty-three compounds. The structure elucidation of these compounds was performed by spectroscopic methods including mass spectrometry, 1D and 2D NMR. Two compounds are not limonoids and the remaining ones are limonoids and could be classified as protolimonoid, gedunin, andirobin and phragmalin compound-types. Sixteen compounds have been found to be new rings and the five known compounds isolated have been identified as methyl angolensante, methyl 6-acetoxyangolensante, secomahoganin, 3β-hydroxy-3-deoxycarapin and xyloccensin K. Efficient Short Step Synthesis of Corey’s Tamiflu Intermediate Catalysts have been used to facilitate the Diels-Alder reaction and almost catalysts developed are Lewis acids. Our lab developed a unique base-catalyzed diastereoselective Diels-Alder reaction of pyridone derivative as diene and electron deficient dienophiles. The unique poly-functionalized bicyclolactam obtained from the reaction between N-nosyl-3-hydroxy-2-pyridone and ethyl acrylate has been used as building block for the synthesis of Corey’s Tamiflu intermediate. This synthesis route is short and the production of different intermediates is simple. Only four chemical transformations and three purification steps are required to obtain the targeted compound, equivalent to the Tamiflu intermediate from the Diels-Alder adduct.博士（工学）Doctor of Philosophy in Engineering鹿児島大

Isothiourea-mediated one-pot synthesis of functionalized pyridines

This work was supported by the Royal Society, Syngenta/EPSRC, The Carnegie Trust for the Universities of Scotland and ERC.Publisher PDFPeer reviewe