The aim of the research documented in this thesis was to explore issues associated with the development of instrumentation for life detection and characterisation in a planetary exploration context. Within this aim, the following objectives had to be achieved: 1. To consider current and near-future single molecule detection (ultra-low lower limit of detection) analytical techniques that would be compatible with development into a Space qualifiable in situ analytical instrument for the detection of biomarkers in a planetary exploration context. 2. To practically consider the consequences of Planetary Protection and Contamination Control on the development of a sample return instrumentation in a planetary exploration context. 3. To consider the implications of flying an in situ instrument on-board a stratospheric balloon platform in order to apply them into a specific planetary exploration mission: In order to achieve the objectives described above, the following work was pursued:  A desk-based European Space Agency (ESA) study was carried out which entailed producing a literature review on single molecule detection technologies that had to be validated by the expert community. This was done by organising an International Workshop on Single Molecule Detection Technologies for Space Applications in March 2009 at Cranfield University, UK. The approved technologies then had to be analysed with standard analytical techniques (i.e., tradeoffs) in order to propose a specific technology for development and present its breadboard implementation and test plans at the end of the study.  A sample return experiment implementing PP&CC constraints and protocols was designed, built, tested and flown on-board the ESA, Swedish Space Corporation (SSC), Swedish National Space Board (SNSB) and German Space Agency (DLR) BEXUS stratospheric balloon platform. The biological and engineering results obtained from the sample return flight were then analysed and lessons learnt obtained for future flights.  Another desk-based study was performed to research future stratospheric balloon platforms for the exploration of Venus’ cloud layer. The in situ instrument previously proposed for the detection of biomarkers for planetary exploration missions was then put forward as a possible payload for a Venusian stratospheric balloon platform and approved by experts during the Venus Exploration Analysis Group (VEXAG) conference held in August 2011 in Washington D.C, USA. The first part of the research involved studying ultra-low lower limit of detection technologies as these have the potential to impact significantly on the technological and scientific requirements of future Space missions. Two systems were proposed: one based on Tandem Mass Spectrometry (with Cylindrical Ion Trap analysers) followed by Surface Enhanced Raman Scattering spectroscopy to create an MS/MS-SERS instrument for the detection of astrobiology biomarkers in Martian regolith, Europan ice and samples from Titan’s hydrocarbon lakes; and a second one as a Stand-Alone SERS system for the detection of biomarkers in Enceladean plumes, Venusian clouds and cometary coma. The second part of the research practically explored the design of instrumentation for stratospheric balloon platforms. CASS•E, the Cranfield Astrobiological Stratospheric Sampling Experiment, was a life detection experiment that aimed to be capable of detecting stratospheric microorganisms. The experiment consisted of a pump which drew air from the Stratosphere through a 0.2 μm collection filter which retained any microorganisms and >0.2 μm particulates present in the pumped air. Due to the expected rarity of microbes in the Stratosphere compared to the known levels of contamination at ground level, Planetary Protection and Contamination Control (PP&CC)constraints were introduced. Therefore PP&CC protocols were followed to implement Space qualified cleaning and sterilisation techniques; biobarrier technology was implemented to prevent re-contamination of the instrument after sterilisation; and cleanliness and contamination was monitored throughout assembly, integration and testing. The third part of the research demonstrated how an instrument from the first part of the study could be proposed as a payload on-board a stratospheric balloon platform with a focused mission context, i.e., a life detection mission for Venus. Therefore, the research concluded with the proposal of a payload for a Venus mission based on SERS technology on-board a stratospheric balloon platform to search for life above or in the mid Venusian cloud cover.

La présence des contaminants organiques dans l’environnement est une problématique aux enjeux aussi bien scientifiques que politiques. Le caractère diffus et continu (différentes et multiples sources) de cette contamination ne permet pas à ces molécules biologiquement actives d’être soumises à une législation. Ces molécules, pouvant être très récalcitrantes, ne sont pas systématiquement éliminées par les systèmes de traitement des eaux conventionnels. Actuellement, de nouveaux procédés biotechnologiques basés sur des enzymes extracellulaires (e.g. Laccase) ou des champignons lignivores permettent l’élimination des composés les plus récalcitrants. Notre compréhension des mécanismes impliqués dans cette élimination reste incomplète. En effet, la biosorption et l’activité des enzymes extracellulaire sont les mécanismes les plus souvent mis en avant pour expliquer l’efficacité des procédés d’élimination fongique, mais ne sont pas capables d’expliquer les performances obtenues pour certains composés pharmaceutiques. Ces lacunes dans nos connaissances sur les mécanismes responsables de l’élimination fongique des contaminants organiques sont un frein à la pleine exploitation de ces procédés de traitement. De plus, il est forcé d’admettre qu’un grand nombre de travaux portant sur l’élimination fongique de contaminants organiques ont été réalisés dans des conditions de hautes concentrations, qui peuvent être peu représentatives des matrices environnementales. Ainsi, les effets observés à plus forte concentration peuvent etre le résultat dû au stress de l’organisme au contact des contaminants (toxicités). Cette thèse adresse deux questions ; ainsi quelle est l’influence des concentrations traces sur de tels procédés ? Et comment expliquer l’élimination de certains contaminants organiques lors des traitements fongiques ? Afin d’apporter des éléments de réponse sur les mécanismes mis en jeux lors de l’élimination fongique, les travaux présentés ici ont été réalisés sur un modèle de champignon lignivore connu pour ses propriétés en bioremediation. Dans un premier temps, un développement analytique permettant la quantification d’une sélection de contaminants organiques à l’état de traces a été réalisé. Cette méthode a permis d’effectuer des analyses de ces molécules à partir d’un seul échantillon environnemental de faible biomasse et à partir d’une seule injection instrumentale. Les résultats de cette thèse démontrent que l’élimination fongique de contaminants organiques résulte de mécanismes plus complexes que précédemment décrits. Notamment, la dégradation est fortement dépendante d’une étape initiale d’internalisation du contaminant par l’organisme ciblé et de la dégradation intracellulaire. Les mécanismes impliqués peuvent ainsi donnés lieux à des réactions de conjugaison intracellulaire des molecules (glucuronide, glutathione). Les résultats démontrent également que ces procédés d’élimination fongique sont efficaces sur une large gamme de concentration en contaminants organiques. Cependant, les faibles concentrations modifient les propriétés physico-chimiques et biologiques de l’organisme testé (i.e. un changement de la morphologie et du profil de la production enzymatique). La réponse biologique n’étant pas directement proportionnelle a l’exposition en contaminant. Cette étude a permis d’accroitre notre compréhension des mécanismes impliqués dans la dégradation fongique de contaminants organiques. Ceci ouvre la voie à de nouvelles études portant sur les interactions entre processus intra — et extracellulaires. Cette thèse contribue également à l’amélioration des connaissances en offrant des outils de compréhension nécessaire à l’optimisation et au développement du potentiel de ces procédés biotechnologiques (ciblage et role des enzymes réeellement impliquées dans les réactions de biocatalyse).

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

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

In recent years, endocrine disruption of corticosteroid signaling pathways in wildlife and humans by environmental chemicals have attracted increasing attention. The integrated potential of chemicals in the aquatic environment that disrupt corticosteroid actions have been evaluated using in vitro glucocorticoid receptor (GR) mediated bioassays. Exogenous natural and synthetic corticosteroids (CSs), which are widely used in human and animal therapeutic applications, were demonstrated to be the most important GR agonists, that can potentially cause adverse effects, especially on aquatic organisms. To date, only a few studies have investigated the occurrence and behavior of GR agonists in the aquatic environment and their removal in conventional wastewater treatment plants. Furthermore, there are hardly any data reported on the removal of GR agonists by advanced water and wastewater treatment, especially those synthetic CSs with high potency. To further understand the fate of GR agonists in water and wastewater treatment processes, a sensitive and robust LC-MS/MS method was successfully developed for analyzing a wide range of GR agonists in various environmental waters. The occurrence of GR agonists in surface water and groundwater was monitored along the Lower Santa Cruz River (SCR). Several GR agonists were detected, and a trend of degradation was observed downstream the two WWTP outfalls for both surface water and groundwater. The fate of GR agonists in a local wastewater treatment plant (WWTP) was investigated, and up to 14 GR agonists were detected at different stages. Highly potent synthetic CSs, including clobetasol propionate (CBP), fluticasone propionate (FTP), fluocinolone acetonide (FCA), and triamcinolone acetonide (TCA), were poorly removed in WWTP. Negative removal of some CSs was observed in primary treatment, which may due to the deconjugation of CS conjugates. Removal of GR agonists in secondary effluent during various advanced water treatment processes, including UV, ozonation, MF, RO and chlorination, were studied. UV and RO appeared to be the most efficient treatment process for the attenuation of GR agonists, followed by ozone, while chlorination had little effects on GR agonists in water. Bench-scale experiments were then carried out to investigate the removal of GR agonists by ultraviolet based advanced oxidation processes (UV/AOPs), and powder activated carbon (PAC). UV/chlorine and UV/H2O2 were demonstrated to be effective in removal GR agonists in wastewater, and UV photolysis would be the predominant mechanism in UV/AOP processes. Four types of PACs were tested for removing GR agonists in wastewater effluent, and Cabot HDB carbon was suggested, while Calgon PWA carbon was not recommended due to its low removal efficiency.

Das Ziel dieser Arbeit war es, eine im Arbeitskreis entwickelte Methode zur Darstellung von unterschiedlich substituierten -Aminopiperidinen zu etablieren und zu verifizieren, indem unser Konzept einer Tandemreaktion zum Einsatz kommen sollte. Diese Reaktionssequenz sollte anschließend zur Totalsynthese von Microconin, einem aus Microcos paniculata isoliertem Alkaloid, genutzt werden. Den ersten Schritt in Richtung -Aminopiperidinderivate machte die Veresterung von L-Pyroglutaminsäure. Nach der Reduktion des Methylesters erfolgte die Aktivierung der Hydroxyfunktion des Alkohols in Form des Tosylats. Die Azideinführung resultierte aus einer nucleophilen Substitutionsreaktion, anschließend daran wurde der Lactam-Stickstoff mit Boc2O und einer katalytischen Menge DMAP geschützt. Das Lactam ist durch den Elektronenakzeptor aktiviert, so dass die Ringöffnung zum Methylester unter sehr milden Bedingungen und ohne weiteren Reinigungsschritt erfolgen konnte. Die Aminofunktion musste mit einer zweiten Schutzgruppe blockiert werden, die anschließende selektive Reduktion mit DiBAl-H in trockenem Ether verlief problemlos und lieferte mit dem Aldehyd das Edukt für Olefinierungen mittels verschiedener Wittig-Reaktionen. Dafür wurden stabilisierte Phosphonate hergestellt und in einer HWE-Reaktion mit dem Aldehyd umgesetzt. Die resultierenden elektronenarmen Olefine gingen dann die intramolekulare Cycloaddition mit dem Azidsubstituenten ein und bauten so den Grundkörper der -Aminopiperidinderivate in einer Reaktionssequenz auf, die wir als Tandem Wittig-[3+2]-Cycloaddition bezeichnen. Die Bildung der primären Triazoline erfolgte stereoselektiv, die Geschwindigkeit der Cycloaddition hing sowohl vom konjugierten Olefinsubstituenten als auch vom vicinalen Substituenten der Azidfunktion ab. Die Konfigurationsbestimmung erfolgte mittels NMR-Spektroskopie durch Analyse der Kopplungskonstanten und NOE-Messungen. Die asymmetrische Induktion der Cycloaddition konnte direkt für die Stereochemie am Piperidinring genutzt werden, indem, nach basischer Triazolin/Diazoamin Isomerisierung, gleich das Diazoamin hydriert wurde. Die Hydrierung der vinylogen Urethane, den Produkten aus der rhodiumkatalysierten Stickstoffextrusion, lieferte ein Diastereomerengemisch, wobei das Verhältnis der Diastereomere hauptsächlich vom Substitutionsgrad des exocyclischen Amins abhängig war. Überraschenderweise fand beim Sulfontriazolin keine Isomerisierung zum Diazoamin statt, daher musste für die Darstellung der Sulfonylmethyl--aminopiperidine eine alternative Route über ein Ketosulfon beschritten werden. Die Synthese von Microconin begann mit der Desoxygenierung von L-Rhamnose durch die sog. Fischer-Zach-Reaktion. Das Rhamnal wurde in einer drei Stufen Eintopfreaktion erhalten und mittels Perlinhydrolyse in den offenkettigen Aldehyd umgewandelt. Die Aktivierung der Hydroxyfunktion als Mesylat resultierte in einer äußerst empfindlichen Verbindung, die nur durch Verwendung des Lindlar-Katalysators mit zufrieden stellenden Ergebnis zum aliphatischen Aldehyd reduziert werden konnte. Eine bimolekulare nucleophile Substitutionsreaktion lieferte bei der Azideinführung zur Schlüsselverbindung sowohl die benötigte funktionelle Gruppe als auch die benötigte Inversion der Konfiguration. Die Tandem HWE-[3+2]-Cycloadditions-Reaktion führte auch bei dem Sulfontriazolin in eine Sackgasse, weshalb wieder eine alternative Syntheseroute eingeschlagen werden musste. Ausgehend von derselben Schlüsselverbindung gelang dies durch eine zinnkatalysierte Umsetzung mit stabilisierten Diazomethan zum Ketosulfon. Der Aufbau des Piperidin-Heterocyclus konnte dann wieder über eine intramolekulare Imin-Bildung des intermediären Amins mit dem Keton erzielt werden. Die diastereoselektive Hydrierung verlief unter Wasserstoffaddition von der sterisch weniger gehinderten -Seite und Ausbildung des all cis Substitutionsmusters. Nach dem erfolgreichen Aufbau des Heterocyclus mussten noch die beiden Heteroatome methyliert werden. Dabei wurden die besten Ergebnisse am Ringstickstoff mit der reduktiven Aminierung erzielt. Bei der anschließenden Abspaltung der Acetylgruppe zeigte sich erstmals, dass das Substitutionsmuster am Piperidinring nicht konfigurationsstabil war, da neben dem erwarteten Alkohol auch das Diastereomer isoliert wurde. Die genaue Ursache für die Epimerisierung nach der N-Methylierung konnte nicht geklärt werden. Die Einführung des Methoxy-Substituenten am Grundkörper erfolgte über eine Williamsonschen Ethersynthese. Bei den Versuchen zur Kupplung des Grundkörpers mit der Seitenkette 2,4-Nonadienal erwies sich der Zusatz von HMPT als förderlich. Weiterhin konnte die Ausbeute an -Hydroxysulfonen durch das Erwärmen der Reaktionsmischung gesteigert werden. In den Folgeschritten der Julia-Olefinierung blieben die Versuche zur Ausbildung der dreifach ungesättigten Struktureinheit in der Seitenkette des isolierten Naturstoffs jedoch erfolglos. / The aim of this work was to establish and verify a route to differently substituted and easy modifiable -amino piperidines using the tandem reaction concept established in our work group. This concept should then be used for the total synthesis of Microconin (3), an alkaloid of Microcos paniculata. In the first step to -amino piperidines L-pyroglutamic acid was converted to its methyl ester according to a modified literature procedure. The reduction of the ester was followed by the activation of the alcohol as its tosylate. The incorporation of azide was achieved by nucleophilic substitution and the lactam moiety was protected using Boc2O and a catalytic amount of DMAP. Protection by an electron acceptor activates the lactam functional group so ring opening with methoxide occurred smoothly at room temperature to yield the azidoester without further purification. The amino function had to be blocked by introduction of a second protecting group, selective reduction in anhydrous ether employing DiBAl-H performed without surprise and resulted in the aldehyde as starting material for olefinations by Wittig type reactions. Several stabilised phosphonates were synthesised and reacted with the aldehyde in the HWE-reaction. The electron poor olefins underwent intramolecular azide cycloaddition building up the -amino piperidine scaffold in a sequence we call tandem Wittig-[3+2]-Cycloaddition. The primary triazoline formation is often diastereoselective whereas the reaction rate depends on the conjugated olefine substituent as well as on stereoelectronic effects caused by the vicinal azido functional group. The resulting configuration was determined by NMR-spectroscopy using analysis of coupling constants and NOESY-techniques. Asymmetric induction in the cycloaddition can be utilised in the piperidine heterocycle after basic triazolin/diazoamine isomerisation and subsequent hydrogenation of the diazo compound. Hydrogenation of the vinylogous urethanes, products of the Rhodium mediated extrusion of nitrogen, lead to a diastereomeric mixture, whereas the diastereomeric ratio depended mostly on the substitution grade of the exocyclic amine. Surprisingly, the isomerisation of sulphono triazoline to the corresponding diazo amin did not happen, so an alternative approach over a ketosulphone to the sulfonylmethyl -amino piperidines had to be found. The synthesis of micrconine started with the deoxygenation of L-rhamnose in a Fischer-Zach reaction. The rhamnal was synthesised in a three step one pot reaction and the ring was opened by Perlin hydrolysis to the aldehyde. Activation of the hydroxyl function as a mesylate resulted in a very unstable compound, witch could only be reduced to the aliphatic aldehyde with sufficient results using the Lindlar catalyst. A bimoleculare nucleophilic substitution reaction of mesylate by azide led to the key intermediate with the necessary inversion of configuration. The tandem Wittig-[3+2]-Cycloaddition led with the sulphon triazoline in a dead end road. Therefore, an alternative synthetic route had to be found again. Starting from the key intermediate, the solution was a tin catalysed reaction with stabilised diazomethane leading to the ketosulphone. The construction of the heterocyclic piperidine core could then be accomplished by an intramoleculare imine formation of the amine intermediate with the ketone. Addition of hydrogen in the diastereoselective hydrogenation took place from the less hindered  face and resulted in an all cis configuration of the molecule. After successful creation of the heterocyclic frame, both hetero atoms had to be methylated. Best results at the ring nitrogen gave reductive aminations. That the substitution pattern of the piperidine heterocycle was configurationally unstable was observed the first time at the following deacetylation by isolating the diastereomeric alcohol besides the desired. The exact reason for the epimerisation after N-methylation could not be evaluated. The last step to the heterocyclic scaffold was the introduction of the methoxy function by a variant of the Williamson ether synthesis. In the coupling reactions of the piperidine core with the side chain unit 2,4-nonadienal the addition of HMPA proofed to be very effective. The yield of -hydroxysulphones could be further improved by slowly warming of the reaction mixture to room temperature. The following steps of the Julia-Olefination to build up the olefinic substructure in the side chain of the isolated natural compound remained without success.

Ziel dieser Arbeit war es die Tandem-Wittig-1,3-dipolare Cycloaddition auf a-Hydroxyurethanderivate zu übertragen und so chirale, nichtracemische b-Amino-piperidylacetatderivaten in möglichst hoher Diastereomerenreinheit darzustellen. Diese Aminopiperidinderivate sollten mit 5-Chloro-2-methoxy-4-methylamino-benzoesäure gekoppelt werden, um die pharmakologische Wirksamkeit zu testen. Als Ausgangssubstanz wurde L-Pyroglutaminsäure (59) verwendet. Über eine dreistufige literaturbekannte Synthese wurden die beiden Halogenpyrrolidinon-derivate 62 und 63 hergestellt. Diese wurden über SN2-Reaktionen mit Natriumazid zu dem Azidopyrrolidinon 64 umgesetzt und durch die Einführung einer Boc-Schutzgruppe in die Verbindung 65 überführt. Die Hydroxyurethanderivate 66 erhält man auf zwei unterschiedlichen Wegen. Zum einen auf dem direkten Weg über eine DiBAl-H-Reduktion von 65 und zum anderen über eine Ringöffnung von 65 mit Natriummethanolat zu 68 und anschließender DiBAl-H-Reduktion. Mit 66 wurden das erste Mal a-Hydroxyurethanderivate einer Tandem Wittig 1,3-dipolaren Cycloaddition unterworfen. Man erhielt unter Essigsäurekatalyse ein Produktgemisch aus dem a,b-ungesättigten Ester 74, dem Triazolin 75 und dem Diazoester 76. Der isolierte a,b-ungesättigte Ester 74 konnte teilweise unter Essigsäaurekatalyse erneut zu den Cycloadditionsprodukten umgesetzt werden. Die Gleichgewichtseinstellung zwischen dem Triazolin 75 und dem Diazoester 76 konnte mit Triethylamin zugunsten des Diazoesters 76 verändert werden. Die Wittigreaktion verläuft unter thermodynamischer Kontrolle stereoselektiv zum E-konfigurierten a,b-ungesättigtem Ester 74. Auch die 1,3-dipolare Cycloaddition verläuft in einem äußerst hohem Maße diastereoselektiv. Durch 1H-NMR-spektroskopische Untersuchungen konnte man die Konfiguration der Cycloadditionsprodukte mit trans bestimmen. Eine Erklärung für die Stereoselektivität der 1,3-dipolaren Cycloaddition liefert die Betrachtung der sterischen und elektronischen Eigenschaften zweier hypothetischer sesselförmiger Konformere des a,b-ungesättigten Esters 74. Über eine katalytische Hydrierung des Diazoesters 76 konnte man einen sehr guten Zugang zu den trans-konfigurierten Piperidylacetaten 2R-78 etablieren. Das andere Diastereomer 2S-78 sollte nach Stickstoffextrusion aus 76 durch diastereoselektive Hydrierung des vinylogen Urethans 80 erhalten werden. Überraschenderweise entstand auch hier 2R-78 als Hauptprodukt. 2S-78 konnte nur als Nebenprodukt isoliert werden. Über eine reduktive Aminierung konnte man eine Methylgruppe am Ringstickstoff von 2R-78 bzw. 2S-78 einführen und erhielt 2R-81 bzw. 2S-81. Mit Moc2O konnte man die beiden Diastereomere 2R-78 und 2S-78 in die geschützten Piperidinderivate 2R-82 und 2S-82 überführen. Die Moc-geschützte Verbindung 2R-82 erhielt man außerdem über eine Synthese des Moc-geschützten Diazoesters 83 und anschließender katalytischen Hydrierung. Nach Abspalten der Boc-Schutzgruppe durch eine Umsetzung der Piperidine 2R-81 bzw. 2S-81 mit methanolischer Salzsäure konnte man die Dihydrochloride 2R-87 bzw. 2S-87 isolieren. Die freien Amine 2R-88 bzw. 2S-88 erhielt man nach Ausschütteln mit gesättigter Natriumcarbonatlösung. Die Piperidylacetate 2R-88 und 2S-88 konnten mit dem Benzoesäurederivat 79 über eine Amidkopplung verbunden werden. Diese Synthese war sowohl über den von GMEINER benutzten Weg, als auch über die Methode von MOHAPATRA und DATTA erfolgreich. Mit 2R-94 und 2S-94 konnten die ersten Nemonaprid-Analoga, die ein a-Aminopiperidingrundgerüst enthalten, dargestellt werden (Schema 47 und Schema 48). Das Piperidylacetat 2R-88 konnte man mit Lithiumaluminiumhydrid zu dem Piperidylethanol 99 umsetzten. / The goal of this studies was to apply the tandem-Wittig-1,3-dipolar cycloaddition to cyclic acceptor substituted a-hydroxyurethanes. Chiral, non racemic 2-alkyl-5-aminopiperidines should be accessible in high diastereomeric excess by using this reaction. The a-aminopiperidine derivatives should be reacted with 5-chloro-2-methoxy-4-methylaminobenzoic acid to the amides and the pharmacological activities of the achieved compounds should be tested. L-pyroglutamic acid was used as a starting material. The synthesis of the key intermediate 66 starts with a three step reaction sequence to the halogenopyrrolidine derivatives 62 and 63. The introduction of azide functionality by nucleophilic substitution to the azidopyrrolidine derivative 64 followed by the protection of the amide group with Boc2O yielded 65. The hydroxyurethane derivative 66 was obtained in two different ways, namely directly by using a DiBAl-H reducing of 65 and on the other hand by ring opening reaction of 65 with sodium methoxide to 68 followed by a DiBAl-H reduction. For the first time the a-hydroxyurethanes 66 as starting material for the tandem-Wittig-1,3-dipolar cycloaddition reaction was applied. A product mixture of the a,b-unsaturated azido ester 74, the triazoline 75 and the diazo ester 76 was achieved by using acetic acid as a catalyst. A mixture of the cycloaddition products could be obtained again by treatment of the isolated a,b-unsaturated azido ester 74 with acetic acid. Rearrangement of the triazoline 75 to the corresponding diazo ester 76 was achieved by addition of triethylamine. Only the E-configurated compound 74 was obtained. This leads to the conclusion that the Wittig reaction is under thermodynamic control. The cycloaddition shows excellent diastereoselectivity. By using 1H-NMR-spectroscopy the trans-configurated cycloaddition product as the single isomer were determined. An explanation for the diastereoselectivity of the 1,3-dipolar cycloaddition is given by a consideration of the steric and electronic properties of two open chain products namely the a,b-unsaturated azido ester 74. An efficient synthetic pathway to the piperidine derivative 2R-78 was established by catalytic hydrogenation of the diazo ester 76. The other diastereomer should be obtained by Rh-mediated extrusion of nitrogen and distereoselective hydrogenation of the vinylogous urethane 80. To our surprise the piperidine derivative 2R-78 was the main product. 2S-78 could only be obtained as the minor stereoisomer. A reductive amination was the most efficient way to introduce a methyl group to the ring nitrogen atom. Introducing Moc2O lead to the protected piperidine derivatives 2R-82 and 2S-82. The protected piperidine derivative 2R-78 was also obtained by the synthesis of the Moc-protected diazo ester 83 and following hydrogenation. After cleavage of the Boc-protecting groups with methanolic hydrogen chloride the dihydrochlorides 2R-87 and 2S-87 were obtained. The free amines 2R-88 and 2S-88 could be coupled with the benzoic acid derivate 79 by using different coupling methods e.g. the method of MOHAPATRA and DATTA. For the first time with 2R-94 and 2S-94 Nemonaprid analogous, which include a ƒÒ-aminopiperidine structure, were obtained.

Thesis advisor: Marc L. Snapper / Tandem processes can have several advantages over multiple single step processes. Non-metathesis transformations of ruthenium alkylidenes were studied and applied to tandem processes. Ruthenium catalyzed tandem RCM/hydroacylation that allows access to tricyclic ring systems from readily available substrates was developed. Mechanistic investigations indicated that this reaction may proceed through a mechanism involving [Ru]-H species. A Ru-catalyzed tandem RCM/olefin isomerization/C-H activation sequence that provides significant advantages in terms of rapid elaboration of simple reaction partners to more complex entities was developed. / Thesis (PhD) — Boston College, 2013. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Um sistema de referência para determinação do equivalente de dose pessoal, HP (10), e um programa de controle da qualidade de sistemas geradores de raios X utilizados em radioproteção inclui a verificação periódica da constância dos feixes de raios X empregados na calibração de instrumentos medidores de radiação em laboratórios de calibração de instrumentos. Neste trabalho foram desenvolvidas duas câmaras de ionização de placas paralelas inseridas em objetos simuladores de tronco humano. Uma das câmaras de ionização possui eletrodo coletor de grafite, para a medida do equivalente de dose pessoal; a segunda câmara de ionização foi confeccionada com eletrodo coletor de alumínio para, juntamente com a primeira câmara de ionização, formarem um sistema Tandem. A dependência energética diferente da resposta das duas câmaras de ionização é que permite a formação do sistema Tandem, que apresenta grande utilidade na verificação da constância de feixes de radiação X. Foram ainda implantados feixes padronizados de radiação X de energias médias (48 keV a 118 keV), nível radioproteção, por meio do desenvolvimento de uma metodologia dosimétrica e da análise dos parâmetros físicos destes feixes. As câmaras desenvolvidas foram testadas em relação às suas características operacionais e foram calibradas em feixes de radiação X, níveis radioproteção, radiodiagnóstico, mamografia e radioterapia, e ainda em campos de radiação gama, seguindo as recomendações internacionais. Apresentaram bom desempenho. Foi estabelecido o procedimento da determinação do equivalente de dose pessoal, Hp (10). / A reference system for the determination of the personal dose equivalent, HP (10), and a quality control program of X-ray equipments used in radioprotection require the periodic verification of the X-ray beams constancy. In this work, two parallel-plate ionization chambers were developed with inner electrodes of different materials, and inserted into PMMA slab phantoms. One ionization chamber was developed with inner carbon electrodes and the other with inner aluminium electrodes. The two ionization chambers can be used as a Tandem system. The different energy response of the two ionization chambers allowed the development of the Tandem system that is very useful for the checking of the constancy of beam qualities. Standard intermediary energy X-ray beams (from 48 keV to 118 keV), radioprotection level, were established through the development of a dosimetric methodology and the analysis of their physical parameters. The ionization chambers were studied in relation to their operational characteristics, and they were calibrated in X-ray beams (radioprotection, diagnostic radiology, mammography and radiotherapy levels) in accordance to international recommendations. They presented good performance. The determination procedure of personal dose equivalent, HP (10), was established.