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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

Chiral lanthanide complexes

Dickins, Rachel Sarah January 1997 (has links)
The use of chiral lanthanide complexes as probes to investigate interactions with other chiral molecules and macromolecules is of particular interest. A key step in the development of such systems is the preparation of a single, rigid enantiomer of the complex which is conformationally rigid on the NMR timescale or the lifetime of the metal-based emission. Chiral europium and terbium complexes are of particular concern as they may function as emissive probes and are amenable to analysis by circular dichroism and circularly polarised lummescence. Charge neutral and cationic complexes of N-substituted 1,4,7,10- tetraazacyclododecane, functionahsed with three phosphmate and one amide pendent arms, or two, three and four pendent amide arms containing a remote chiral centre, have been prepared. The chirality of the remote stereocentre determmes the helicity of the arrangement of the pendent arms and the conformation of the 12-membered macrocycle.The chiral europium and terbium complexes of the tetraamide complexes exist as single, rigid enantiomers, exhibiting a well-defined metal-based circularly polarised emission. Circular dichroism studies reveal that exciton coupling occurs between adjacent pairs of 1-naphthyl chromophores of tetraamides, whereas the constitutional 2- naphthyl isomers exhibit excimer formation. The behaviour of the di-, tri-, and tetraamide complexes in the presence of added anions has been investigated. The measurement of the luminescent lifetime of the excited state and the circularly polarised emission exhibited by the enantiopure complexes in aqueous solution affords a novel way of signalling the presence of selected oxy-anions.
2

Chiral aspects of the disposition and pharmacology of the enantiometers of ethosuximide

Mifsud, Janet January 1995 (has links)
No description available.
3

Stereoisomerism of Dimethyl Muconate

Bearden, Robert Gene January 1950 (has links)
The acid which is analogous to the next member of the diphenylpolyenes, 1,4-diphenylbutadiene, is muconic acid. This acid has been chosen to be investigated in an effort to isolate all the stereoisomers of a set containing more than two isomers.
4

One-Pot Stepwise Approach to β-Enaminoketoesters through “Masked” 1,3-Aza-Dipoles

Yan, Z., Wu, Na (Anna), Liang, D., Wang, H., Pan, Y. 23 July 2014 (has links)
Yes / t-BuOK-mediated rearrangement of 1,3-ketoesters with 2-(azidomethyl) aromatics in a two-step, one-pot telescoped sequence affords β-enaminoketoesters in moderate to good yields. A novel pathway is proposed in which the umpolung of the azide is achieved from electrophilicity to nucleophilicity via deprotonation and undergoes nucleophilic attack onto the 1,3-ketoester.
5

Controlling Dynamic Stereoisomerism in Gated Molecular Baskets

Stojanovic, Sandra 16 August 2012 (has links)
No description available.
6

Optimal determination of steric mass action model parameters for beta-lactoglobulin using static batch experiments

Barz, T., Loffler, V., Arellano-Garcia, Harvey, Wozny, G. January 2010 (has links)
No / In this work, parameters of the steric mass-formalism SMA are optimally ascertained for a reliable determination of the adsorption isotherms of beta-lactoglobulin A and B under non-isocratic conditions. For this purpose, static batch experiments are used in contrast to the protocols based on different experimental steps, which use a chromatographic column. It is shown that parameters can already be determined for a small number of experiments by using a systematic procedure based on optimal model-based experimental design and an efficient NLP-solver. The in different works observed anti-Langmuir shape of the isotherm for small concentrations of beta-lactoglobulin A was corroborated. Moreover, we also found indications for a porosity variation with changing protein concentrations.
7

Stereoselective transport of drugs across the blood-brain barrier (BBB) in vivo and in vitro : pharmacokinetic and pharmacodynamic studies of the (S)- and (R)-enantiomers of different 5-HT₁A receptor agonists and antagonists /

Yan, Hongmei. January 2002 (has links)
Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 4 uppsatser.
8

A study on pharmacokinetic and pharmacodynamic effects of salbutamol-isomers /

Naidu Sjöswärd, Kerstin January 1900 (has links) (PDF)
Diss. (sammanfattning) Linköping : Univ., 2003. / Härtill 4 uppsatser.
9

From achiral to chiral analysis of citalopram /

Carlsson, Björn, January 2003 (has links)
Diss. (sammanfattning) Linköping : Univ., 2003. / Härtill 4 uppsatser.
10

The development of novel myosin inhibitors

Lawson, Christopher Peter Abiodun Tevi January 2011 (has links)
This thesis describes a structure activity relationship (SAR) study on the recently discovered small molecule tool blebbistatin (S)-21 with particular emphasis on the development of novel synthetic protocols suitable for the rapid synthesis of libraries of blebbistatin analogues. These analogues are potentially of use as novel myosin inhibitors Chapter 1 introduces the concept of chemical biology with particular emphasis on chemical genetics. This approach has rekindled the search for new chemical tools for the investigation of biological systems. The success of blebbistatin (S)-21, which was identified in a chemical genetic study, as a research tool was also discussed. The link between several myosin classes and genetic diseases such as coeliac disease, Crohn’s disease, deafness, dermatitis, familial hypertrophic cardiomyopathy, Griscelli disease and ulcerative colitis indicate that potent inhibitors which show selectivity towards specific myosin isoforms may be of great value as tools for the study of these conditions. The plan for the SAR study around (S)-21 was outlined. Chapter 2 describes the studies undertaken to develop an efficient synthetic route to N1-alkyl analogues of (S)-21 suitable for the parallel synthesis of chemical collections. These studies culminated in the synthesis of an intermediate (S)-66 from which novel N1-alkyl analogues were synthesised. The biological evaluation of these N1-alkyl analogues was discussed. Chapter 3 describes the development of a protocol suitable for the parallel synthesis of collections of N1-aryl analogues of (S)-21 via the intermediate 66. The application of this protocol to the synthesis of a collection of racemic N1-aryl and heteroaryl analogues of (S)-21 and their biological evaluation was presented. Chapter 4 describes the successful rational design and synthesis of a novel fused thiophene ring containing inhibitor of myosin II. The structure of this compound was proposed by modelling of the existing co-crystal structure of (S)-21 bound to the metastable state of Dictyostelium discoideum myosin II (S1dC) and sought to optimise the π-π stacking interaction displayed by (S)-21 with the tyrosine 261 residue within its binding site. The biological evaluation of this novel analogue was discussed. In Chapter 5 the studies conducted to investigate the contribution of ring-C to the binding affinity of (S)-21 were described. The development of alternate routes to (S)-21, in an attempt to avoid difficulties experienced during the synthesis of some analogues of (S)-21, are described. The synthesis and biological investigation of the fluorescent dye PPBA whose binding site has been suggested to overlap with that of (S)-21 was also reported.

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