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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.
71

A stability and mechanistic study of pendant arm ligand complexes / by Sonya L. Whitbread.

Whitbread, Sonya L. January 1999 (has links)
Erratum pasted onto front-end paper. / Includes bibliographical references. / xi, 225 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates alkali and alkaline earth complexes of pendant arm ligands. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 1999
72

A structural thermodynamic and equilibrium study of chiral pendant arm triaza macrocyclic ligand complexes: towards the formation of metal-ion activated molecular receptors : a thesis submitted for the degree of Doctor of Philosophy at the University of Adelaide (Faculty of Science) / by Jennifer Megan Weeks.

Weeks, Jennifer Megan January 2000 (has links)
Errata page pasted opposite title page. / Includes bibliographical references. / x, 147 leaves : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Addresses the structural, equilibrium and thermodynamic aspects of pendant arm donor triaza macrocyclic ligands and their alkali metal and zinc complexes. Involves ab initio molecular modelling, x-ray crystallographic studies, potentiometric stability constant determinations and NMR kinetic studies. / Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 2000?
73

Elektronenübertragung als Mechanismus der Meerwein-Reduktion von Diazoniumsalzen mit Äthern und Acetalen und, Ein Beitrag zum Mechanismus der Jacobson'schen Indazolsynthese /

Werner, Rüdiger, Werner, Rüdiger, January 1969 (has links)
Thesis (doctoral)--Westfälische Wilhelms-Universität zu Münster. / Vita. Includes bibliographical references (p. 116-121).
74

Methylation of the metal salts of 2- and 4-pyridine diazotates

Thamavit, Chirasarit 01 January 1977 (has links) (PDF)
No description available.
75

Stereoselective Radical Transformations by Co(II)-Based Metalloradical Catalysis:

Wang, Xiaoxu January 2022 (has links)
Thesis advisor: X. Peter Zhang / Chapter 1. Co(II)-Based Metalloradical Catalysis for Stereoselective Radical Cyclopropanation of Alkenes This Account summarizes our group’s recent efforts in developing metalloradical catalysis as a one-electron approach for catalytic radical cyclopropanation of alkenes with diazo compounds. Chapter 2. Asymmetric Radical Process for General Synthesis of Chiral Heteroaryl Cyclopropanes We have developed a Co(II)-based metalloradical system that is highly effective for asymmetric radical cyclopropanation of alkenes with in situ-generated heteroaryldiazomethanes. Through fine-tuning the cavity-like environments of newly developed D2-symmetric chiral amidoporphyrins as the supporting ligand, the optimized Co(II)-based metalloradical system is broadly applicable to pyridyl and other heteroaryldiazomethanes for asymmetric cyclopropanation of a wide range of alkenes, providing general access to valuable chiral heteroaryl cyclopropanes in high yields with excellent diastereoselectivities and enantioselectivities. Chapter 3. Enantioselective Metalloradical 1,6-C–H Alkylation of In Situ-Generated Alkyldiazomethanes for Synthesis of Chiral Piperidines We have disclosed an effective Co(II)-based metalloradical system as a fundamentally different approach to harness the potential of 1,6-HAA radical process, enabling asymmetric 1,6-C–H alkylation of in situ-generated alkyldiazomethanes to construct chiral piperidines. Supported by an optimal D2-symmetric chiral amidoporphyrin ligand, the Co(II)-catalyzed alkylation system is capable of activating a wide array of alkyldiazomethanes containing C(sp3)–H bonds with varied steric and electronic properties, providing access to chiral piperidines in good to high yields with high enantioselectivities from readily accessible 4-aminobutanal derivatives. In addition to practical attributes, such as operational simplicity and mild conditions, the metalloradical system is highlighted by its tolerance to different functional groups as well as compatibility with heteroaryl units. Chapter 4. Design and Synthesis of A Novel D2-Symmetric Chiral Porphyrin for Co(II)-Based Metalloradical Catalysis A novel D2-symmetric chiral amidoporphyrin derived from chiral cyclopropanecarboxamide containing diphenyl units has been effectively constructed based on Co(II)-catalyzed asymmetric cyclopropanation of alkenes. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.
76

Conception, synthèse et vectorisation de molécules apparentées à l'isocombrétastatine A-4 : Exploration de nouvelles réactivites des composés diazo-précurseurs / Design, synthesis and vectorization of isocombretastatin A-4 analogues : Exploration of new reactivities of diazo-precursor compounds

Lamaa, Diana 15 November 2019 (has links)
Les travaux de thèse concernent la synthèse et la vectorisation d'analogues de la combrétastatine A-4, une molécule naturelle connue pour ses propriétés anti-vasculaires et cytotoxiques. Ces recherches se situent à l’interface de la chimie et de la biologie.D'une part, des études en méthodologie de synthèse, mettant en œuvre des réactions de couplages entre des composés diazo-précurseurs et des halogénoarènes ou des amines ont été réalisées dans le but de fournir des outils de synthèse nécessaires à la constitution de chimiothèques. Ces études ont conduit à la synthèse des 2-pyridilalkylamines à partir de pyridotriazole et d’amines, à la synthèse du motif 1,1-diaryléthyl via une réaction green ainsi qu'à l’accès au noyau benzofurane à travers une réaction « one-pot ».D’autre part, des analogues duaux de l'isocombrétastatine A-4, inhibiteurs de la tubuline et des histones désacétylases ont été développés. L'évaluation biologique de ces analogues a permis d’identifier deux molécules « lead » dont les activités antiprolifératives sur des lignées cellulaires cancéreuses sont de l'ordre du nanomolaire. D'excellents résultats d'inhibition de la polymérisation de la tubuline et de l’histone déacétylase 8 ont également été observés.Finalement, des essais de vectorisation de quelques analogues de l’isoCA-4 sous forme de liposomes ou d’ADC ont été réalisés. / The thesis reports the synthesis and vectorization of combretastatin A-4 analogues, a natural molecule known for its anti-vascular and cytotoxic properties. Our research work is at the chemistry-biology interface.On the first hand, synthetic methodology studies were performed, indeed coupling reactions between diazo-precursors and haloarenes or amines have been carried out providing new and interesting synthethic tools. These studies led to the synthesis of 2-pyridylalkylamines from pyridotriazole and amines, as well as to the synthesis of the 1,1-diarylethylene compounfs via a green reaction and finally to access to the benzofuran ring through a one-pot fashion reaction ".On the other hand, dual targeting analogs of isocombretastatin A-4 with tubulin and histone deacetylases inhibition properties have been developed. The biological evaluation of these analogs allowed us to identify two lead molecules whose antiproliferative activities on cancer cell lines are in the order of nanomolar. These molecules showed an excellent tubulin polymerization and histone deacetylase 8 inhibitions.Finally, vectorization assays of some isoCA-4 analogs using liposomes or ADCs were performed.
77

The development of an expedient method for the synthesis of a diverse series of cyclopropane [alpha]-amino acids

Wurz, Ryan P. January 2004 (has links)
Thèse diffusée initialement dans le cadre d'un projet pilote des Presses de l'Université de Montréal/Centre d'édition numérique UdeM (1997-2008) avec l'autorisation de l'auteur.
78

Développement et application d'une nouvelle méthodologie de méthylénation catalytique de composés carbonylés

Paquet, Valérie January 2004 (has links)
Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.
79

Fragmentation, Rearrangement, And C-H Insertion: Reactions Of Vinyl Cations Derived From Diazo Carbonyls

Cleary, Sarah Elizabeth 01 January 2018 (has links)
Many commercialized medicinal compounds are analogs of chemicals isolated from sources found in nature (also called natural products). However, the natural sources of these chemicals, such as plants, fungi, or insects, only offer small quantities of these bioactive agents. Thus, it is typically desirable to find ways to synthesize these products and their analogs in large quantities using cost-effective methods that also minimize the impact on the environment. It is also important to develop strategies that expedite the process of modifying the natural products, which allows medicinal chemists to determine which functional groups are enhancing or deleterious to the bioactivity. In the Brewer lab, I have investigated organic reactions and methodologies with this aim - to find ways to efficiently break and form carbon-carbon bonds, and to utilize these reactions in the total synthesis of structurally related natural products. The total synthesis of natural products is often used to showcase a methodology's utility by applying it in a more complex structure. The Lewis acid-promoted fragmentation of γ-silyloxy-β-hydroxy-α-diazo esters to provide tethered aldehyde ynoates was discovered and developed in the Brewer lab. This methodology was extended to bicyclic systems, in which the ring-fusion bond fragmented as a way to afford 10-membered ring ynones and ynolides, which are traditionally challenging to synthesize. This work will exhibit how the fragmentation reaction that provided 10-membered ynolides has the potential to lend itself to the synthesis of several structurally related, bioactive natural products via a divergent total synthesis strategy. In addition, this dissertation will describe our discovery that modifying the diazo carbonyl precursor to a β-hydroxy-α-diazo ketone changes the course of the Lewis acid-promoted reaction. Rather than a fragmentation sequence, the compound is converted to a vinyl cation, which undergoes a rearrangement then a C-H insertion of a second vinyl cation intermediate. This transition metal-free rearrangement/C-H insertion reaction provided cyclopentenone products. The migratory aptitudes of non-equivalent substituents in the cationic rearrangement step will also be discussed. Finally, the disparate reactivities of vinyl cations derived from diazo ketone, diazo ester, and diazo amide precursors will be detailed from an experimental and computational perspective. The results underscore the fact that this rearrangement and C-H insertion reaction may eventually be an effective way to prepare complex cyclopentyl-containing structures, which are common motifs in biologically active natural products.
80

Spin selective reactivity of arylcations ; Part II: Anthraquinone oligonucleotide conjugates as probes of electron transfer in DNA

Gasper, Susan M. 05 1900 (has links)
No description available.

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