자료유형 | 학위논문 |
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서명/저자사항 | Synthesis of Nitrogen Heterocycles for Methodology Development, Reaction Discovery, and Ion Channel Modulation. |
개인저자 | Zhu, Jie Sheng. |
단체저자명 | University of California, Davis. Chemistry. |
발행사항 | [S.l.]: University of California, Davis., 2019. |
발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
형태사항 | 547 p. |
기본자료 저록 | Dissertations Abstracts International 81-03B. Dissertation Abstract International |
ISBN | 9781085796422 |
학위논문주기 | Thesis (Ph.D.)--University of California, Davis, 2019. |
일반주기 |
Source: Dissertations Abstracts International, Volume: 81-03, Section: B.
Advisor: Kurth, Mark J. |
이용제한사항 | This item must not be sold to any third party vendors.This item must not be added to any third party search indexes. |
요약 | The discovery of a new variation on the Davis-Beirut reaction is described in which an atypical heterocyclic framework (the anthranil or benzo[c]isoxazole) is formed as the result of diversion of a key reactive intermediate away from its expected reactivity via a potentially general approach to reaction design and development. Experimental and computational support for the proposed mechanism and origins of altered reactivity are described.Reaction options in the Davis-Beirut reaction of an o-nitrobenzylamine substrate, are reported to explain the nucleophilic addition selectivity of this one-pot indazole-forming process, i.e. alkoxide vs hydroxide vs amine addition to the key o-nitrosoimine intermediate. The hydroxide addition/deprotection pathway as well as the fate of the resulting o-nitrosobenzaldehyde were both uncovered with several o-nitrobenzylamine substrates, and design elements required for an efficient double Davis-Beirut reaction, inspired by new mechanistic insights, were defined.o-Nitrosobenzaldehyde is a reactive intermediate useful in the synthesis of nitrogen heterocycles. Previous strategies for using o-nitrosobenzaldehyde involve its isolation via chromatography and/or formation under harsh conditions. This intermediate was photochemically generated in situ from o-nitrobenzyl alcohols in a mild, efficient manner for the construction of 1,2-dihydro-3H-indazol-3-ones using an aqueous solvent at room temperature. This convenient reaction offers several advantages over reported methods. The commercially available photoreactor employed 3 x 18 W bulbs outputting broad emission above 365 nm.A concise, one-step route to indazolones from primary alkyl amines and o-nitrobenzyl alcohols is reported. The key step in this readily scalable indazolone forming process involves base-mediated in situ o-nitrobenzyl alcohol to o-nitrosobenzaldehyde conversion. Although this functional group interconversion was previously known to be useful for 2H-indazole synthesis, its reactivity was modulated for indazolone formation.The Cadogan cyclization is a robust but harsh method for the synthesis of 2H-indazoles - a valuable class of nitrogen heterocycles. Although nitrene generation by exhaustive deoxygenation is widely accepted as the operating mechanism in the reductive cyclization of nitroaromatics, non-nitrene pathways have only been theorized previously. Here, 2H-indazole N-oxides were synthesized through an interrupted Cadogan/Davis-Beirut reaction and are presented as direct evidence of competent oxygenated intermediates |
일반주제명 | Organic chemistry. |
언어 | 영어 |
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