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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

Studies toward the synthesis of the microsclerodermin natural products

Shuter, Emily Clare January 2006 (has links)
Doctor of Philosophy (PhD), Science / A concise stereo-selective synthesis of a protected form of APTO 1, an unusual amino acid component of microsclerodermin C 2, was undertaken. Sequential Sharpless Asymmetric Aminohydroxylation (AA) and Asymmetric Dihydroxylation (AD) reactions were used to introduce the chiral amino and hydroxyl groups. Specific directing groups were chosen to ensure high regio- and enantio-selectivity in these reactions. The target compound was reached in a linear reaction sequence of fourteen steps. The strategy was designed to generate common intermediates which could be used to access analogous amino acid fragments in other microsclerodermins. A protected form of AETD 3, from microsclerodermin E, was synthesised via a late-stage common intermediate. Initial studies into the modification of the sequence to allow access to AMPTD 4 and 10-methyl AMPTD 5 were made.
2

Studies toward the synthesis of the microsclerodermin natural products

Shuter, Emily Clare January 2006 (has links)
Doctor of Philosophy (PhD), Science / A concise stereo-selective synthesis of a protected form of APTO 1, an unusual amino acid component of microsclerodermin C 2, was undertaken. Sequential Sharpless Asymmetric Aminohydroxylation (AA) and Asymmetric Dihydroxylation (AD) reactions were used to introduce the chiral amino and hydroxyl groups. Specific directing groups were chosen to ensure high regio- and enantio-selectivity in these reactions. The target compound was reached in a linear reaction sequence of fourteen steps. The strategy was designed to generate common intermediates which could be used to access analogous amino acid fragments in other microsclerodermins. A protected form of AETD 3, from microsclerodermin E, was synthesised via a late-stage common intermediate. Initial studies into the modification of the sequence to allow access to AMPTD 4 and 10-methyl AMPTD 5 were made.
3

Synthèse de nouveaux dérivés de l'acide β-hydroxyaspartique β-Substitués : inhibiteurs du transport du glutamate dans le Système Nerveux Central (SNC) / Synthesis of new optically pure β-substituted β-hydroxy aspartic acid derivatives : Inhibitors of glutamate transport in the Central Nervous System (CNS).

Mekki, Sofiane 29 April 2012 (has links)
Nos travaux ont porté sur la mise au point de synthèse de nouveaux dérivés β-substitués β-hydroxy aspartates : Inhibiteurs du transport du glutamate dans le système nerveux centrale (SNC). Ces analogues d'aspartates ont été caractérisés par différentes méthodes spectroscopiques (RMN-1H, RMN-13C et HRMS) et leur pureté énantiomérique a été confirmée par analyses HPLC chirale et des mesures de pouvoir rotatoire. Ce manuscrit est organisé en trois chapitres : la première partie présente un point bibliographique sur le système glutamatergique dans le SNC, en rappelant les différents récepteurs et transporteurs du glutamate dans ce système ainsi leurs agonistes et antagonistes spécifiques.Puis, nous avons décrit un aperçu sur les différentes synthèses de dérivés aspartates β-substitués et leurs activités inhibitrices vers les transporteurs du Glu dans le SNC.Afin d'avoir une grande diversité dans la structure les dérivés β-substitués β-hydroxy aspartates et réduire le temps de préparation et le nombre d'étapes de synthèse, nous avons développé dans la troisième partie de ce manuscrit deux stratégies originales et récentes pour préparer des dérivés -substitués -hydroxy aspartates via une aminohydroxylation asymétrique de Sharpless, qui est considérée comme l'étape clé dans cette synthèse.Enfin, Les résultats préliminaires de tests biologiques sur les dérivés β-substitués β-hydroxy aspartates protégés montrent que ces composés ne présentent aucune toxicité vers les cellules nerveuses de l'hippocampe de rat. L'étude de la cytotoxicité et l'activité inhibitrice de dérivés β-substitués β-hydroxy aspartates totalement déprotégés vis à vis du transport du glutamate dans le SNC sont actuellement en cours. / Our work focused on the development of synthesis of originals β-substituted β-hydroxy aspartates derivatives: Inhibitors of glutamate transport in the central nervous system (CNS).These analogs of aspartate have been characterized by various spectroscopic methods (1H-NMR, 13C-NMR and HRMS) and their enantiomeric purity was confirmed by chiral HPLC analysis and D measurement.This manuscript is organized into three chapters: the first part presents a bibliographical point of the glutamatergic system in CNS, recalling the different receptors and glutamate transporters in this system and their specific agonists and antagonists.Then, we described an overview of the various syntheses of β-substituted aspartates derivatives and their inhibitory activities toward glutamate transporters in CNS.In order, to have a great diversity in the structure of β-substituted β-hydroxy aspartates derivatives and reduce preparation time and the number of synthetic steps, we have developed in the third part of this manuscript two recent and original strategies for prepare β-substituted β-hydroxy aspartates derivatives via asymmetric aminohydroxylation Sharpless, who is considered the key step in this synthesis. Finally, preliminary results of biological tests on optically pure aspartates derivatives showed no toxicity to nerve cells of the rat hippocampus. The study of the inhibitory activity of these derivatives towards transport of glutamate in CNS is currently underway.

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