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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.
171

Reductive aldol cyclizations using Stryker's reagent and polystyrene-supported triphenylarsine in carbon-carbon bond forming reactions

Lau, Chi-yin, January 2007 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available in print.
172

Silver catalyzed enyne cyclization reactions

Chen, Haoguo. January 2009 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 115-116). Also available in print.
173

Structure-activity relationship of octreotide analogues labeled with rhenium and technetium-99m

Dannoon, Shorouk, Lewis, Michael R. Jurisson, Silvia. January 2009 (has links)
Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 25, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Silvia Jurisson and Dr. Mike Lewis. Vita. Includes bibliographical references.
174

Generation of 1,3-dipoles containing carbon, nitrogen, sulphur and phosphorus /

Zhu, Shuguang, January 1997 (has links)
Thesis (Ph. D.), Memorial University of Newfoundland, 1998. / Bibliography: leaves 142-156.
175

Ring-closing metathesis for the synthesis of carbocyclic and heterocyclic intramolecular Baylis-Hillman adducts

Song, Eunho. Krafft, Marie E. January 2005 (has links)
Thesis (M.S.)--Florida State University, 2005. / Advisor: Dr. Marie E. Krafft, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Sept. 19, 2005). Document formatted into pages; contains 147 pages. Includes bibliographical references.
176

Gold-catalyzed cycloadditions an approach toward complex molecular frameworks via transannular, intermolecular, and intramolecular methods /

Bailey, Lauren N. January 2010 (has links)
Title from first page of PDF document. Includes bibliographical references (p. 55-57).
177

Tridentate nitrogen ligands derived from 2,6-bis-hydrazinopyridine (BHP) preparation and study of the 2,6-bis-hydrasonopyridines, 2, 6-bis-pyrazolylpytidines, and 2,6-bis-indazolylpyridines /

Duncan, Nathan C. Garner, Charles M. January 2009 (has links)
Thesis (Ph.D.)--Baylor University, 2009. / Includes bibliographical references (p. 233-237).
178

Syntheses and Structures of Substituted Polycyclic Molecules and Analysis of the Two-Dimensional NMR Spectrum of Thiele's Ester

Lu, Shao-Po 05 1900 (has links)
Diels-Alder cycloaddition of methylcyclopentadienes to 2,5-dibromo-p-benzoquinone was performed. A single, isomerically pure cycloadduct was isolated, whose structure was assigned via analysis of its 1-D and 2-D NMR spectra. Diels-Alder cycloaddition of methylcyclopentadienes to 2 -methoxy-p-benzoquinone was performed. A single, isomerically pure cycloadduct was isolated, whose structure was assigned via analysis of the 1-D and 2-D NMR spectra of this cycloadduct and its reduction product obtained via stereo-specific reduction with sodium borohydride in the presence of cerous chloride. The structure of Thiele's ester was assigned via analysis of its 1-D and 2-D NMR spectra.
179

Synthetic Applications of Ketene Cycloadditions: Natural and Novel Pyrethroid Insecticides

Ko, Jinren 08 1900 (has links)
A new synthetic route to natural and novel pyrethroid acids was developed utilizing ketene cycloaddition which is a significant improvement over existing syntheses. The newly synthesized pyrethroid acids were converted to pyrethroid esters and used to study structure-activity relationships. The cycloaddition of dichloroketene with 2,5-dimethyl-2,4-hexadiene yields (2+2) cycloaddition products, 2,2-dichlorocyclobutanones. The reductive removal of one chlorine atom from these cycloaddition products gave monochlorocyclobutanones which underwent a Favorskii-type ring contraction to yield cis- and trans-chrysanthemic acids. 4-Methyl-1,3-pentadiene was also used as a precursor in this synthetic scheme to yield an analogue of the chrysanthemic acid. These results are consistent with a concerted cycloaddition process involving a dipolar transition state. The zinc reduction is not a regiospecific reaction which accounts for the two regioisomers of the monochlorocyclobutanones. The Favorskii-type ring contraction is a regiospecific reaction. A variety of different bicyclo(3.1.0)alkenecarboxylates and bicyclo(4.1.0)heptenecarboxylates were synthesized from alkylcyclopentadiene and fulvene derivatives. These new bicyclo pyrethroid acids are structurally similar to the natural chrysanthemic acid but are rigid and locked in a single conformation which is likely the least stable conformer of the natural acid. The acids were converted to pyrethroid esters and tested against the housefly and cockroach. The test results indicate that the bicyclo pyrethroids synthesized are not as active as the natural pyrethroid. Apparently, these bicyclo pyrethroids with structures similar to the less stable conformer of the natural pyrethroids are of little consequence as it binds to the target site in the insect. In an effort to learn more about the conformational requirements of the pyrethroid acid, a new bicyclo-spiro pyrethroid system with a structure similar to the most stable conformation of the natural pyrethroid was designed and synthesized. These bicyclo-spiro pyrethroids were derived from a new isopropylidenecyclobutane derivatives as a starting compound instead of a conjugated diene. The test results of these bicyclo-spiro pyrethroid esters revealed a much greater activity against the housefly and cockroach. This study establishes that the more stable conformer of the natural pyrethroid acid provides a much higher toxicity against the insects tested.
180

Reactivity studies of arene-cis-diols in cycloadditions and potassium permanganate oxidations: synthesis of the corresponding arene-trans-diols and an approach to the synthesis of (+)-pancratistatin

McKibben, Bryan P. 06 June 2008 (has links)
Potassium permanganate oxidations and novel cycloaddition chemistry of the arene-cis-diols (7) were investigated. It was found that permanganate oxidation of arene-cis-diols yielded a mixture of 2 products, (157a) and (157b) in low yield. The influence of the C1-substituent on the outcome of the reaction was found to be a complex mixture of steric and electronic effects. In the area of cycloaddition chemistry of protected (7), this thesis describes novel [4+2] cycloadditions with quinones along with the first published report of benzyne and nitrile oxide cycloadditions of these homochiral molecules. The structure of the cycloadducts were elucidated by nOe as well as 2D-NMR analysis and were supported by Frontier Molecular Orbital theory. Finally, arene-trans-diols (200) were synthesized from (7) by a multistep stereoselective protection/deprotection sequence utilizing the Diels-Alder reaction. These compounds serve as intermediates in an approach to the amaryllidaceae alkaloid (+)-pancratistatin (12). / Ph. D.

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