>Magister Scientiae - MSc / A novel monomer (Phenazine-2,3-diimino(pyrrole-2-yl)–PDP) derived from the condensation reaction between 2,3-diaminophenazine and a pyrrole derivative has been synthesized as a hinge molecule in the design of a zig-zag polymer with actuation possibility. The monomer was polymerized chemically and electrochemically to produce the new polymer material – polymerized Phenazine-2,3-diimino(pyrrole-2-yl) PPDP. Two very crucial properties of a good actuator material, relate specifically to its solubility testing and electrical conductivity. The hinged polymer material was studied intensively in terms of its spectroscopy; Fourier Transform Infrared - FTIR, 1H’NMR, thermal properties (Differential Scanning Calorimetry-DSC and Thermogravimetric Analysis-TGA) as well as voltammetry and conductivity. Conductivity was evaluated using three different approaches including; 4 probe measurements, plotting of I/V curves based on potentiostatic measurements and an electrochemical impedance experiment using a dielectric Solartron interface. Electrochemical kinetics of the polymer prepared as a thin film at glassy carbon electrode (GCE) was also done and it was clear that the thin film conductivity was vastly different from the compressed pellet conductivity (thick film). The zig-zag polymer was then further modified by homogeneous inclusion of gold nanoparticles to improve conductivity and solubility, in the thick film arrangement. Conductivity of the thin film was studied by electrochemical impedance spectroscopy with the relative charge transfer values being determined for unmodified and modified polymer systems. The solubility testing of the material plays an important role as it is required for a wide range of experimental applications. The zig-zag polymer showed great promise for applications; in dye sensitized solar cells and free standing interpenetrating polymer network (IPN), solubility testing and electrical conductivity would need to be improved in order to be used in these applications.

Ce travail de thèse s’articule autour de la synthèse totale des alcaloïdes de la famille Rhazinilam, potentiels agents anticancéreux. Dans ce contexte, deux méthodologies clés ont été développées. Premièrement, une réaction de cyclisation-migration de groupements sulfonyles catalysée à l'or (I) conduisant à des sulfonates de pyrroles a été optimisée et le champ d'application a été largement étendu. En tirant profit de la carbophilie des catalyseurs d’or (I), une réaction en cascade comprenant une séquence de cyclisation-migration-hydrocarbonation a été mise en place, permettant la synthèse d’indolizines ou de pyrroloazépines dans un procédé en un seul pot. Deuxièmement, des conditions réactionnelles sans précèdent par catalyse au palladium ont été développées pour le couplage de Suzuki-Miyaura impliquant des substrats de types sulfonates de pyrroles. Ces conditions ont été appliquées de façon efficace sur divers types de partenaires (aryle, hétéroaryle, vinyle sulfonates ou analogues halogénés) mais également utilisées dans différents types de couplages (Sonogashira, Buchwald). Ces méthodologies ont ensuite été appliquées à la synthèse totale du Rhazinilam et permis d’ouvrir la voie à la synthèse des Kopsiyunnanines et du Leuconolam. En parallèle, de nouveaux complexes associant des polyoxométallates et des carbènes d'or (I) ont été synthétisés, caractérisés et utilisés en catalyse hétérogène. / This PhD work was articulated around the total synthesis of the Rhazinilam family alkaloids, potential anticancer agents. In this context, two key methodologies have been developed. Firstly, a gold(I)-catalyzed cyclization-sulfonyl migration reaction leading to pyrrole sulfonates has been optimized and the scope was largely extended. By taking advantage of the carbophilicity of gold(I) catalysts, a cascade reaction including a sequence of cyclization-migration-hydrocarbonation has been implemented, allowing the synthesis of indolizidines or pyrroloazepines in a one pot process. Secondly, unprecedented reaction conditions were developed for palladium-catalyzed Suzuki−Miyaura cross-coupling using pyrrole sulfonates as substrates. These conditions have been applied efficiently on various types of partners (aryl, heteroaryl, vinyl sulfonates or halogenated analogues) but also used in different types of cross-coupling (Sonogashira, Buchwald). These methodologies were then applied to the total synthesis of Rhazinilam and to open the way to the synthesis of Kopsiyunnanines and Leuconolam natural products. In parallel, new complexes combining polyoxometalates and gold(I) carbenes have been synthesized, characterized and used in heterogeneous catalysis.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

As biocélulas a combustível proporcionam meios de se obter energia de maneira mais sustentável, limpa e renovável e apresentam grande potencial para serem usadas como fontes de energia alternativas para dispositivos eletrônicos de baixa demanda energética. Esta dissertação investiga a bioeletro-oxidação de etanol pela enzima Álcool Desidrogenase (ADH) empregando-se bioânodos com polimerização simultânea do mediador (poli - verde de metileno) e polímero condutor (polipirrol). Uma vez preparado o bioânodo foram realizados estudos para verificar a oxidação do cofator (NADH), formação do produto da bio-oxidação de etanol, estabilidade e também estudos visando aumentar a eficiência energética gerada empregando nanotubos de carbono para aumento de área eletroquímicamente ativa e melhor comunicação com os sítios ativos das enzimas. Foi também preparada uma biocélula completa sem membrana polimérica visando diminuir resistência de transferência de prótons do sistema, com a configuração final constituída de ADH/NAD+, etanol, Lacase/O2 com e sem MWCNT. O bioânodo se mostrou relativamente estável, apresentando um decaimento médio de 36% do valor inicial da densidade de potência após 20 semanas de estocagem. Quando operado em condição contínua (tempo = 4h, E (V)= ½ PCA), o decaimento foi de 39% e de 66% em 12 horas de operação. Os valores de densidade de potência foram melhorados com a adição de MWCNTs sobre o suporte de C antes da eletropolimerização do filme simultâneo, em pH 8,9, obteve-se 275 + 12 ?W cm-2. A eletrólise para este sistema mostrou a formação de acetaldeído com conversão de 18% de etanol. Para a biocélula completa, os melhores resultados foram com a presença de MWCNTs no bioânodo, obtendo-se uma potência de 12,5 +0,9 ?W cm-2. Os resultados obtidos são bastante promissores comparado com a literatura atual e mostram que esse sistema pode ser empregado para construção de BFC. / Biofuel cells provide the means to obtain energy in a more sustainable, clean, and renewable way and have great potential as alternative energy sources for low-energy electronic devices. This dissertation investigates ethanol bioelectrooxidation by the enzyme Alcohol Dehydrogenase (ADH) at bioanodes with simultaneous polymerization of the mediator (polymethylene green) and conductive polymer (polypyrrole). After preparing the bioanode, we investigated cofactor (NADH) oxidation, the ethanol biooxidation product,and bioanode stability. We also conducted studies to increase the generated energy efficiency by using carbon nanotubes to augment the electrochemically active area and to improve communication with the enzyme active sites. We also prepared a complete biofuel cell without polymer membrane to decrease the system proton transfer resistance: the final configuration consisted of ADH / NAD +, ethanol, Laccase , and O2 with or without MWCNTs. The bioanode was relatively stable. The mean decay was 36% of the initial power density after 20 weeks of storage. When the bioanode was operated in continuous condition (time = 4h, E (V) = ½ PCA), the decay was 39% and 66% in 12 hours of operation. The power density values increased upon addition of MWCNTs to the C-support before simultaneous film electropolymerization at pH 8.9, to give 275 + 12 ?W cm-2. Under electrolysis conditions, this system produced acetaldehyde and converted 18% of ethanol. For the complete biofuel cell, the best results were with the presence of MWCNTs in the bioanode, which provided a power of 12.5 +0.9 ?W cm-2. The results obtained here are quite promising if compared to the current literature and show that this system can be used to construct a BFC.

L'objectif de cette étude consiste à développer des bio-architectures à base de nanotubes de carbone mono-feuillet à visées électroanalytiques. Pour ce faire, différentes méthodes de fonctionnalisation de nanotubes de carbone ont été proposées à savoir la fonctionnalisation en solution, par trempage et par électropolymérisation en se servant des interactions π entre les nanotubes de carbone et des molécules π-conjugués (le pyrrole-biotine, le pyrène-biotine et le pyrèneadamantane). Les matrices utilisées pour la conception des biocapteurs sont basées sur les systèmes d'affinité entre l'avidine et la biotine, et entre l'adamantane et la β- cyclodextrine. La comparaison des performances des différents biocapteurs a permis de déterminer la méthode la plus adéquate pour la fonctionnalisation des nanotubes de carbone. Cette dernière consiste à former une monocouche de monomères par simple trempage puis de la renforcer par électropolymérisation oxydative dans une solution exempte de monomère. Cette stabilisation de la couche adsorbée préserve une excellente accessibilité à la surface de l'électrode sous-jacente. Les surfaces fonctionnelles qui en résultent ont été caractérisées par des méthodes physico-chimiques d'analyse.

The development of small-molecules which target nucleic acids, more specifically the minor groove of DNA, in a sequence specific manner and control gene expression are currently being investigated as potential therapeutic compounds for the treatment of various diseases, including cancer, as well as viral and bacterial infections. The naturally occurring compounds netropsin and distamycin have been shown to demonstrate antitumor and antibacterial properties. Currently, there are synthetic efforts to create pyrrole and imidazole-containing polyamide derivatives of netropsin and distamycin that show potential as medicinal agents. Synthetic pyrrole and imidazole-containing polyamides are potentially useful for targeting and modulating the expression of genes, including those associated with cancer cell growth. The key challenges that must be overcome to realize this goal of using synthetic polyamides in the treatment of disease are the development of polyamides with low molar mass so the molecules can readily diffuse into cells and concentrate in the nucleus. In addition, the molecules must have appreciable water solubility, bind DNA sequence specifically, and with high affinity. As part of a systematic study within the authors’ laboratory, our goal is to develop polyamides which can be synthesized readily yet possess excellent sequence specificity, stronger binding affinity, high solubility in biological media and enhanced cell penetration and nuclear localization properties. There is a need to develop a library of modified polyamides which target DNA and exhibit improved biological properties. The present study is a systematic examination of the binding properties of various modified synthetic polyamide compounds. The synthetic polyamide derivatives presented have more potential as therapeutic candidates over other synthetic polyamides because of their increased water solubility, smaller molecular weights, and molecular design, thus, allowing them to penetrate into cells and localize in the nucleus.

The first part of the thesis presents the reinvestigation of the synthetic and mechanistic aspects of manganese (III) acetate mediated reactions. The main concern about this subject was to perform a &cent / - acetoxylation reactions of enones and saturated systems in shorter reactions times and higher yields than the ones known in literature reproducibly. Although successful a &cent / -acetoxylation of a great variety of substrates have been reported so far, there are some problems associated with the use of Mn(OAc)3. Considering that there are not many simple methods for the direct acetoxylation of enones, optimization of Mn(OAc)3 mediated a &cent / -acetoxylation of enones and reaching its maximum potential has a great importance from a synthetic and economical point of view. In the second part of the thesis, 1,2,4-trisubstituted pyrrole derivatives were the target molecules to be synthesized. Although there are quite a number of methods available for the synthesis of pyrroles, most of them involve multistep synthetic operations which lower the overall yield. There are limited reports on the preparation of the enantiomers of pyrrole derivatives having 1-N directly linked to the stereogenic center. Thus, developing a new synthetic method for the efficient preparation of polysubstituted pyrroles without racemization still remains an attractive goal.

Während meiner Dissertation beschäftigte ich mich mit der Synthese von polyhalogenierten Pyrrolalkaloiden. Im Zentrum der Darstellung dieser Verbindungen stand die von mir in meiner Diplomarbeit erfolgreich zur Synthese von Pentabrompseudilin angewandte silber-katalysierte Cyclisierung von N-tosylsubstituierten Homopropargylaminen. So konnte das Pentachlorpseudilin in der zweiten Totalsynthese überhaupt sowie mehrere gemischt halogenierte synthetische Derivate aufgebaut werden. Diese Verbindungen konnten in einer Kooperation mit Herrn Prof. Gutzeit aus der Fachrichtung Biologie der TU Dresden und Herrn Prof. Manstein von der Medizinischen Hochschule Hannover, als hochwirksame Myosin ATPase-Inhibitoren identifiziert werden. Bei den verschieden halogenierten Verbindungen ließen sich deutliche Unterschiede in der inhibitorischen Aktivität feststellen. Ein zum Pentabrompseudilin benzologes Indolderivat, welches in einer kurzen Synthese aufgebaut werden konnte, war hingegen nicht aktiv. Im zweiten Teil der Promotion beschäftigte ich mich in einer Kooperation mit Dr. Kurzchalia vom Max-Planck-Institut für Molekulare Zellbiologie und Genetik (Dresden) mit der Synthese von hormonell aktiven Steroiden, speziell den Cholesten-26-säuren, welche Liganden für den hormonellen Rezeptor DAF-12 des Nematoden Caenorhabditis elegans repräsentieren. Die an C-25 R-konfigurierten Säuren waren in der Literatur mit einer deutlich geringeren Aktivität als die 25S-Säuren beschrieben. Die 25R-Steroide waren synthetisch leicht aus kommerziell erhältlichem Diosgenin zugänglich. So konnten alle drei 25R-Säuren in kurzen Synthesen dargestellt werden. In deren Verlauf wurden verschiedene Oxidations- und Schutzgruppenreaktionen eindrucksvoll angewendet. Für die Einführung der 25S-Konfiguration in der Seitenkette sollte eine EVANS-Aldolreaktion an geeignetem Startmaterial angewandt werden. In der Tat führte die Verwendung eines chiralen Oxazolidinons stereoselektiv zum gewünschten Enantiomer in sehr guten Ausbeuten, selbst bei großen Ansätzen. Zur weiteren Transformation musste die durch die Aldolreaktion eingeführte Hydroxygruppe an C-24 entfernt werden. Dies gelang in exzellenter Ausbeute mit Hilfe einer radikalischen Deoxygenierung nach BARTON und MCCOMBIE. So konnte in acht Stufen ein zentrales Syntheseintermediat gewonnen werden, dass in alle drei Naturstoffe überführt werden konnte. Damit waren ausreichende Mengen für biologische Untersuchungen hergestellt worden. Mit der gesättigten (25S)-Dafachronic Acid konnte ein neuer Ligand für DAF-12 synthetisiert werden. Gleichzeitig konnte gezeigt werden, dass die Existenz einer Doppelbindung in den Cholesten-26-säuren für die biologische Aktivität unerheblich ist. Für weitere biologische Tests konnten neue Normethylderivate des Cholesterols gewonnen werden. Diese zeigten zum Teil ungewöhnliche biologische Aktivität. Außerdem wurden Versuche zu an verschiedenen Positionen bromierten Cholesterolderivaten unternommen. Im letzten Teil meiner Dissertation konnten neue hoch hydroxylierte Steroide dargestellt werden, die in einer Kooperation mit Prof. Franzblau vom Institute for Tuberculosis Research (Chicago, USA) auf ihre Aktivität gegen Mycobacterium tuberculosis getestet werden sollten. Dabei konnte eine ungewöhnliche 1,2-anti-Hydroborierung beoachtet werden, deren Mechanismus noch genauer untersucht werden muss.

For grafting polypyrrole on oxidized surfaces, 3-substituted pyrrole alkyl phosphonic acids, 11-(pyrrol-3-yl undecyl) trimethoxysilanes and 1-substituted pyrrole alkyl organosilanes with different chain length were designed and successfully synthesized as adhesion promoters. These new derivatives were studied for their adsorption behavior on oxide substrates and chemical or electrochemical deposition of polypyrrole over modified oxide surface or electrodes. Several analytical techniques such as contact angle measurement, surface plasmon resonance spectroscopy (SPR), UV-VIS Spectroscopy, grazing incident FTIR, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to characterize the adsorbed layers on different substrates. Contact angle measurement and ellipsometry data showed that high concentrations in apolar hydrocarbon solvent and long reaction times are sufficient to form tightly packed monolayer of 1-substituted pyrrole alkyl monochlorosilanes (PMCS) on substrates. Adsorption kinetics were studied by SPR and showed that the adsorption took place within a few seconds, then continuously increased and reached a plateau. The orientation of these synthesized monomers is investigated to be well-suited for use as adhesion promoter. CV-measurements showed that 3-substrated pyrrole derivatives had lower oxidation potential, whereas 1-substituted pyrrole derivatives had higher oxidation potential compared with pyrrole. Surface deposition of polypyrrole on the adhesion promoter modified (silane-modified and phosphonic acid-modified) substrates by chemical and electrochemical polymerization were investigated. PPy films formed on the modified surfaces by surface chemical polymerization showed a better adhesion compared to those on the unmodified surfaces. The morphology of PPy films was influenced by the alkyl chain length of the adhesion promoter and the deposition condition, such as choice of oxidant and solvent. The thickness of the resulting PPy films were controlled by the polymerization conditions, such as choice of solvent, deposition time, pyrrole to oxidant ratio and monomer concentration. The thickness of the deposited PPy film was estimated in the range of 10-400 nm by AFM and ellipsometry. The electrical properties were studied by current-voltage (j-V) measurement. Temperature dependence of j-V characteristics of Si/SiO2/PPy/PMCS-16/Al films revealed that the current increases with temperature, the film shows a typical semiconductor behavior. The use of these adhesion promoters modified electrode for electrochemical polymerization resulted in adhesive polypyrrole films.Also the 3-substituted pyrrole phosphonic acids were found to be homo-and co-polymerizable (with pyrrole) under chemical methods. TGA showed that homopolymers are less stable than polypyrrole due to the 3-substitution. he homopolymer of 3-substituted phosphonic acid derivatives of pyrrole is soluble. Films coated from the MeOH solution of homopolymer could be successfully used as humidity sensors. It is observed that the resistivity of the 3-substituted homopolypyrrole sensors increases and capacitance decreases during exposure to humid air. The polypyrrole films obtained by surface chemical polymerization was also used as humidity sensors.

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