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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

Kritische beurtheilung der methoden welche zur trennung und quantitativen bestimmung der verschiedenen chinaalkaloide benutzt werden ...

Hielbig, Carl. January 1880 (has links)
Inaug.-diss.--Dorpat. / "Angewandte literatur": p. 84-86.
2

Kritische beurtheilung der methoden, welche zur trennung und quantitativen bestimmung der verschiedenen chinaalkaloide benutzt werden ...

Hielbig, Carl. January 1880 (has links)
Inaug.-diss.--Dorpat. / "Angewandte literatur": p. 84-86.
3

Monographie der Gattung Cinchona L.

Kuntze, Otto. January 1984 (has links)
Diss.--Freiburg--Philosophische Facultät, 1878.
4

An experimental enquiry into the similarity in virtue between the Comus florida and Sericea, and the Cinchona officinalis of Linnæus together with an inquiry into the modus operandi of astringent vegetables in preventing the putrefactive fermentation /

Walker, John M. January 1803 (has links)
Thesis (M.D.)--University of Pennsylvania, 1803. / Microform version available in the Readex Early American Imprints series.
5

Cinchona-derived organocatalysts for asymmetric carbon-carbon bond formation

Marcelli, Tommaso. January 2007 (has links)
Proefschrift Universiteit van Amsterdam. / Met samenvatting in het Nederlands.
6

Enantioselective epoxidation of simple alkenes based upon the concept of pi-interactions-facial recognition

Antequera-Garcia, Gema 20 December 2005 (has links)
The aim of our project is to build new catalysts for the asymmetric epoxidation of alkenes using ð-interactions as fundamental factors for the control of the facial selectivity. It was decided to employ cinchona alkaloid derivatives as the basic core of our catalysts. We envisage that the alkene would interact selectively with the aromatic rings of the catalyst to give the corresponding epoxide in good enantiomeric excess. Quinuclidine derived cataysts of simplified structures were synthesised to find the best conditions for the experiments using chiral cinchona derivatives. An important result to be taken into account in the development of the chiral catalysts was the influence of the counterion on the conversion rate. The triflate gave the highest epoxidation rates for trans-â-methylstyrene. The use of a mixture MeOH/ DMM/ H2O led to a two fold increase in reaction rate and is recommended to increase the van der Waals interactions between the aromatic rings of the catalyst and the alkene. New catalyst amd a new epoxidation protocol for the epoxidation of alkenes mediated by dioxiranes have been disscussed .Encouraging results have been obtained from this work.
7

Empire's experts the politics of knowledge in Spain's royal monopoly of quina (1751-1808) /

Crawford, Matthew James. January 2009 (has links)
Thesis (Ph. D.)--University of California, San Diego, 2009. / Title from first page of PDF file (viewed July 9, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 369-389).
8

Chiral discrimination of dicarboxylic acids with Cinchona alkaloids

Komba, Christele Lydia January 2017 (has links)
Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2017. / This thesis is aimed at the investigation of the chiral discrimination process during diastereomeric salt formation, when selected cinchona alkaloids are exposed to racemic mixtures of tartaric acid derivatives. This research is based on the use of (+)‐cinchonine, (‐)‐cinchonidine, (‐)‐quinidine and (+)‐ quinine, which served as chiral bases, in order to resolve racemates of O,O'‐dibenzoyl‐tartaric acid (DBTA) and O,O'‐di‐p‐toluoyl‐tartaric acid (DTTA). Cinchona alkaloids were selected because of their abilities to form salts with the targeted acids. DBTA and DTTA are commonly used resolving agents to separate racemic bases via diastereomeric salt formation, and they are also commercially available and affordable chiral acids. Results were obtained from all combination but only the experiments with cinchonidine were included in this thesis, namely [CIND+][L‐DBTA‐], 2[CIND+][D‐DBTA2‐], [CIND+][LDTTA‐] and 2[CIND+][D‐DTTA2‐]∙2DMSO∙0.7H2O. Experimental analytical techniques, such as thermal analysis, powder X‐ray diffraction, and single crystal X‐ray diffraction were used to analyze the harvested diastereomeric salts. A correlation of molecular parameters derived from the structures and an investigation of the mechanism, which drives the resolution process were discussed. The thesis also summarizes the findings on 8 inclusion compounds of (‒)‐O,O'‐dibenzoyl‐(2R,3R)‐tartaric acid (L‐DBTA) and (‒)‐O,O'‐di‐p‐toluoyl‐(2R,3R)‐tartaric acid (L‐DTTA) or their racemic mixtures, (rac)‐ DBTA and (rac)‐DTTA, with DMSO and water: (rac)‐DBTA∙H2O, (rac)‐DBTA∙DMSO, L‐DBTA∙H2O, LDBTA∙ DMSO, (rac)‐DTTA∙H2O, (rac)‐DTTA∙DMSO, L‐DTTA∙H2O, and L‐DTTA∙DMSO. The discussed inclusion compounds were obtained serendipitously, as a product of the pre‐screening of suitable solvents to dissolve both the acids and the cinchona alkaloids during the discrimination experiments. Only few crystal structures of solvates of these two tartaric acid derivatives are known up to now, and fewer of these structures do exist when both the racemic and the enantiopure acid encapsulates the same solvent. The synthesis and structural analysis of these inclusion compounds contribute to the pool of available crystal structures when comparing chiral vs. achiral crystal forms of the same compounds.
9

(¤@)Synthesis of 3,4-Disubstituted £\,£]-Unsaturated£_-Lactams (¤G)Formal Synthesis of Hydrocinchonine and Hydrocinchonidine

Wang, Yung-Sheng 03 July 2003 (has links)
We have successfully developed an efficient approach to 3,4-disubstituted £\,£]-unsaturated £_-lactams from glutarimide, and proved to be applicable for the synthesis of hydrocinchonine and hydrocinchonidine.
10

Dr. Johan Eliza de Vrij, apotheker en kinoloog 1813-1898 : "suum cuique /

Algera-van der Schaaf, Margaretha Anna Wilhelmina, January 1994 (has links)
Proefschrift--Rijksuniversiteit te Leiden, 1994.

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