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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Exploration of New Reactivities of Azetidinols and Alkynylborates / アゼチジノールとアルキニルボラートの新規反応性の探索

Shimamoto, Yasuhiro 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18301号 / 工博第3893号 / 新制||工||1597(附属図書館) / 31159 / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 村上 正浩, 教授 杉野目 道紀, 教授 大江 浩一 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
2

Asymmetric Synthesis of Nitrogen Containing Bioactive Compounds via the Utilization of Enantiopure p-Toluenesulfinimines

Xu, Peng January 2013 (has links)
The research objective of this thesis research was to develop new methods for the asymmetric synthesis of amine derivatives using p-toluenesulfinimines. Enantiopure sulfinimines are versatile chiral building blocks for the asymmetric synthesis of alkaloids. Sulfinimines were prepared by the condensation of (S)- or (R)-p-toluenesulfinamide with aldehydes and ketones in good to excellent yields, which were prepared from the commercially available Anderson reagent. The first research project was the development of a new method for the preparation of enantiopure anti-anti- α-lkyl β-amino ketones and was accomplished by the stereoselective α-alkylation of enolates of sulfinimine derived β-amino esters. The anti- α-lkyl β-amino esters were transformed to their corresponding Weinreb amides by reacting with lithium dimethyl hydroxyl amine without epimerization. Reactions of the Weinreb amides with Grignard and organolithium reagents afforded the corresponding anti- α-lkyl β-amino ketones in modest yields and high optical purity. The modest yields are the results of competition between addition and reduction of the Weinreb amide. anti- α-lkyl β-amino ketones are important chiral building blocks for the asymmetric synthesis of nitrogen-containing biologically active molecules, such as pyrrolidines, piperidines and other alkaloids. To further illustrate the utility of sulfinimine -derived enantiopure N-sulfinyl anti- α-lkyl β-amino ketones, they was applied to the asymmetric synthesis of the unknown anti-C5, C6 derivative of 2,3,4,6-tetrasubsituted indolizidine 221-T. The key step in the synthesis was the stereoselective construction of the piperidine ring of the 5,6,8-tri-substituted indolizidine and was realized via the use of an acid-catalyzed intramolecular Mannich cyclization. The indolizidine was readily transformed in to the key intermediate 7-hydroxyl-2,3,4,6-tetrasubsituted indolizidine in high stereoselectivity and yield. Changing the sequence of chemical operation steps avoided the production of the side product β-pyrrole ketone. Reduction of the intermediate piperdinone, followed by ring-closing metathesis and reductive catalytic hydrogenation afford the bicyclic indolizidine with overall 76% yield of 3 steps. The C-2 branched cocaine analogs are thought to have varied bioactivities and potent therapeutical uses compared to other positions of substituted cocaine analogs. However, reports on the synthesis of such analogs are few. The first example of preparation of a cocaine analog having a dimethylphosphonate group at the C-2 position was reported. The key step in forming the required isoxazolidine intermediate, which controls the required cis stereochemistry at C-2 and C-3, was a novel microwave induce stereoselective [3+2] intramolecular cycloaddition of an α,β-unsaturated pyrrolidine nitrone. The use of the microwave irradiation techniques significantly reduce the time required for isoxazolidine formation from 96 hours to five hours. / Chemistry

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