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Arico, Joseph William. "3-Substituted Purines: Methodology, Synthesis, and Studies of DNA Hydration in the Minor Groove." Thesis, Boston College, 2010. http://hdl.handle.net/2345/1824.
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Thesis advisor: Mary F. Roberts<br>As the central repository of biological information and ultimate mediator of all processes underlying the activities of living organisms, nucleic acids are the sine qua non for life as we know it. Biological research over the past century and more has revealed much of the structure and function of nucleic acids, revealing in turn how life begins, changes, reproduces, and ends. We glimpse how life has become what it is and perhaps what it may become. This work seeks to understand the ramifications of altering a single nitrogen of the purine nucleoside components of nucleic acids. As will be shown, purine analogs lacking the N3 nitrogen have altered interactions with proteins, water, and other molecules. Replacement of this nitrogen with a C-H, C-CH3, or C-CH2OH functionality impacts the structure and biological interactions of a DNA duplex containing these alterations in ways not entirely foreseen when this work began over ten years ago. The synthetic effort needed to obtain purine nucleosides containing each of these modifications is significant. Along the way, new methodologies applicable both to the synthesis of purine analogs and natural purine nucleosides are described<br>Thesis (PhD) — Boston College, 2010<br>Submitted to: Boston College. Graduate School of Arts and Sciences<br>Discipline: Chemistry
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Copin, Chloé. "Exploration moléculaire en série imidazo[2, 1-b][1, 3, 4]thiadiazole : applications à la synthèse d'inhibiteurs de kinases impliqués dans les maladies neurodégénératives." Thesis, Orléans, 2013. http://www.theses.fr/2013ORLE2074.
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Depuis plus d’un siècle, la chimie hétérocyclique représente l’un des plus vastes domaines de recherche en chimie organique. En particulier, les hétérocycles bicycliques fusionnés à 5 chaînons, contenant à la fois des atomes de soufre et d’azote, présentent, de par leur rareté et leur potentiel biologique, un champ d’intérêt croissant pour les équipes de recherche et développement académiques ou des entreprises pharmaceutiques. Parmi les nombreux composés bicycliques [5-5], notre étude s’est focalisée sur le noyau imidazo[2,1-b][1,3,4]thiadiazole décrit sporadiquement dans la littérature et pour lequel les voies d’accès actuelles ne se limitent qu’à une seule méthode faisant intervenir une étape de cyclisation et des conditions drastiques. Ce verrou entraine inéluctablement une faible diversité fonctionnelle autour de cet hétérocycle, restreignant ainsi les domaines d’applications notamment biologiques. Afin de pallier à cette problématique, nous avons initié une étude de la réactivité de chacune des trois positions fonctionnalisables du bicycle imidazo[2,1-b][1,3,4]thiadiazole, développant ainsi diverses réactions pallado-catalysées (Suzuki-Miyaura, CH-arylation, Buchwald-Hartwig), de substitution nucléophile aromatique et de Pictet-Spengler. L’étude des propriétés biologiques des différents composés synthétisés et hautement valorisables durant ces travaux a abouti à la découverte de deux séries de molécules inhibant sélectivement les kinases DYRK-1A et CLK-1, deux protéines d’intérêt dans le traitement des affections du système nerveux central (neuropathies, Alzheimer…)<br>For more than a century, heterocyclic chemistry is one of the largest area in organic chemistry research. In particular, because of their rarity and their biological potential, [5-5] fused ring heterocycles containing both sulfur and nitrogen atoms are a large area of interest for both academic and industrial research and development teams. Among these numerous [5-5] bicycles, our study is focused on imidazo[2,1-b][1,3,4]thiadiazole scaffold, which is quite few described in the literature and whose pathways are limited to almost one method involving a cyclisation step and drastic conditions. This lock leads inevitably to low functional diversity around this heterocycle, thus restricting its applications, including biological. In order to overcome this problematic, we then initiated the reactivity study of each three positions of the bicycle imidazo[2,1-b][1,3,4]thiadiazole, developing thereby several palladium couplings (Suzuki-Miyaura, direct arylation, Buchwald-Hartwig), as well as aromatic nucleophilic substitution and Pictet-Spengler reaction. The study of the biological properties of the different compounds synthesized in this work and highly valuable led to the discovery of two series of molecules, inhibiting selectively DYRK-1A and CLK-1, two kinases of interest in the treatment of dysfunction of central nervous system (neuropathies, Alzheimer…)
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Hallé, François. "Conception, développement et synthèse de ligands du TSPO dans le but de traiter les maladies neurodégénératives." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF054/document.
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Les neurostéroïdes sont des composés endogènes qui peuvent moduler la transmission synaptique et avoir un effet neuroprotecteur dans les maladies neurodégénératives. Les systèmes régulant leur biosynthèse ne sont pas connus mais la première étape de celle-ci peut être régulée par la protéine TSPO. Cette protéine mitochondriale facilite le transport du cholestérol vers l’intérieur de la mitochondrie pour y être métabolisé en prégnénolone. Ce stéroïde est le précurseur principal de la biosynthèse des neurostéroïdes et l’utilisation in vitro de ligands du TSPO permet d’augmenter sa sécrétion. Dans ce travail de thèse, nous avons ainsi cherché à développer de nouvelles familles de ligands solubles du TSPO augmentant la sécrétion de prégnénolone. Le développement de ces nouvelles familles a nécessité la réalisation d’une méthodologie de synthèse faisant intervenir une réaction de cyclisation pallado-catalysée de type Buchwald-Hartwig. Une étude de solubilité des composés synthétisés a été effectuée expérimentalement, leur activité a été évaluée par des méthodes fonctionnelles et leur effet neuroprotecteur a été testé sur un modèle cellulaire de la maladie d’Alzheimer<br>Neurosteroids are endogenous compounds which can alter the synaptic transmission and enhance neuroprotection in neurodegenerative diseases. The systems that regulates their biosynthesis are not described but its first step ca be regulated by the TSPO. This mitochondrial protein facilitates the transport of cholesterol to the mitochondrial matrix to be metabolized in pregnenolone. This steroid is the precursor of neurosteroid biosynthesis and in vitro use of TSPO ligands induces its secretion. For this project, we looked forward to develop new families of soluble TSPO ligands that can increase pregnenolone production. The access to 3-amino-3,4-dihydroquinolin-2-ones required the establishment of a synthesis methodology of a palladium-catalyzed cyclization following Buchwald-Hartwig amination. A solubility study of synthesized compound was performed, their activity was established based on functional assays and their neuroprotective effect was evaluated on a cellular model of Alzheimer disease
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Zeinyeh, Waël. "Conception et synthèse d'hétérocycles azotés et de dérivés stéroïdiens, modulateurs potentiels de transporteurs ABC (glycoprotéine-P)." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00874305.
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La multichimiorésistance est caractérisée par une résistance simultanée à des agents chimiothérapeutiques de structures diverses, induite notamment par l'efflux des substances actives hors des cellules. Les transporteurs ABC (ATP-Binding Cassette) sont des protéines transmembranaires impliquées dans cet efflux et qui participent à l'échec du traitement de certains cancers. Par ailleurs, ce mécanisme d'efflux a également été évoqué dans le cadre de la résistance de certains microorganismes aux antimicrobiens. Dans cette étude, nous avons conçu et synthétisé des dérivés susceptibles d'inhiber certains transporteurs ABC, en particulier, la glycoprotéine-P (Pgp) impliquée dans la multichimiorésistance des tumeurs humaines, et CpABC3, rencontré chez le parasite Cryptosporidium parvum. Dans un premier temps, nous avons synthétisé trois dérivés de type 4-alkyl-imidazo[4,5-b]pyridin-7-one, hétérocycles destinés à se fixer sur le site à ATP des transporteurs ABC. L'activité de ces composés a été évaluée vis-à-vis d'un fragment recombinant (H6-NBD1) de CpABC3, et un de ceux-ci a montré une liaison (faible) à ce fragment. Nous avons ensuite préparé dix-sept dérivés bivalents susceptibles d'inhiber la Pgp, constitués d'une molécule d'adénine (ciblant le site à ATP) reliée à la progestérone (ciblant le site aux stéroïdes) par un bras de géométrie variable. Ces dérivés ont été testés sur des lignées cellulaires K562/R7 surexprimant la Pgp, et un de ceux-ci a montré une activité supérieure à celle de la progestérone. Enfin, nous avons mis au point une synthèse de chaînes de type oligocyclohexylidène, qui sont de bons candidats pour constituer des bras espaceurs rigides
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Ta, Hue Thu. "Reactions of 5-(3-alkyltriazeno)imidazole-4-carboxamide." Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315657.
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Campos, Fátima de. "Síntese e atividade biológica de imidas derivadas da 4-Aminoantipirina." Florianópolis, SC, 2001. http://repositorio.ufsc.br/xmlui/handle/123456789/81474.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em Química.<br>Made available in DSpace on 2012-10-19T04:25:45Z (GMT). No. of bitstreams: 0Bitstream added on 2014-09-25T19:52:47Z : No. of bitstreams: 1
181665.pdf: 4463435 bytes, checksum: cf584d1d881317feaa6ab54b96a69ece (MD5)<br>Síntese de novas imidas obtidas através da reação entre a 4-aminoantipirina e diferentes anidridos e avaliação da atividade biológica. O composto mais promissor foi selecionado e diferentes modificações estruturais foram realizadas. Os compostos foram obtidos em moderados a excelentes rendimentos (40-95%) e suas estruturas foram confirmadas por dados espectroscópicos (IV e RMN).
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Thiverny, Maryse. "1-oxy-2,3-dihydro-imidazol-4-ones : des intermédiaires et des cibles." Université Joseph Fourier (Grenoble), 2010. http://www.theses.fr/2010GRE10174.
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Les travaux présentés s'articulent autour de synthons nitrone de type N-oxy-imidazolidinone, pour lesquels nous avons exploré les applications possibles. Nous avons développé une nitrone achirale, CYCNO, accessible en 3 étapes depuis un ester de la glycine (66%) et une nitrone chirale, MiPNO. Celle-ci a été obtenue sous forme énantiopure par une méthode de résolution nouvelle ; chaque énantiomère est ainsi accessible avec des rendements de 15 et 17% depuis l'ester de la glycine. CYCNO a été utilisée comme modèle pour étudier la réactivité des N-oxy-imidazolidinones vis-à-vis des halogénures d'aryl- et hétéroarylmagnésium, préparés par insertion de magnésium ou par échange iode-magnésium. La réoxydation des hydroxylamines intermédiaires mène à une nouvelle série de nitrones, pouvant être utilisées comme pièges à radicaux libres. MiPNO a été utilisée pour la préparation d'acides aminés non naturels, arylglycines et α-aryl,α-méthylglycines. La séquence met en jeu une réaction d'addition d'organomagnésiens totalement diastéréosélective. Sept cibles arylglycines ont été préparées. De plus, des réactions de cycloaddition 1,3-dipolaire entre MiPNO et différents alcènes ont conduit à des isoxazolidines, obtenues de façon hautement régio- et diastéréosélective. Le cycloadduit peut être converti en l'α-amino-γ-lactone correspondante en une seule opération, ce qui a mené à la préparation d'un nouveau γ-hydroxy-α-amino-acide énantiopur<br>The present work deals with N-oxy-imidazolidinone type nitrones and the possible applications thereof. We developed an achiral nitrone, CYCNO, available in 3 stages from a glycine ester (66%) and a chiral nitrone, MiPNO. The latter was obtained in enantiopure form by a new optical resolution method; each enantiomer is accessible in 15 and 17% yield from the glycine ester. CYCNO was used as a model to study the reactivity of N-oxy-imidazolidinones toward aryl and heteroarylmagnesium halides, prepared by magnesium insertion or iodine-magnesium exchange. The reoxidation of the intermediate hydroxylamine led to a new family of nitrones, which may be used as spin traps. MiPNO was used for the preparation of unnatural amino acids, arylglycines and α-aryl,α-methylglycines. The sequence involves a totally diastereoselective addition of organomagnesium reagents. Seven arylglycine targets were prepared. In addition, 1,3-dipolar cycloaddition reactions between MiPNO and various alkenes led to isoxazolidines, in excellent regio- and diastereoselectivity. The cycloadduct can be converted into the corresponding α-amino-γ-lactone in a single operation, allowing the preparation of a new enantiopure γ-hydroxy-α-amino-acid
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Kerscher-Hack, Silke [Verfasser]. "Synthese potentieller GABA-uptake-Inhibitoren mit 1H-Imidazol-4-ylessigsäure- und 3-(1H-Imidazol-2-yl)propansäure-Grundstruktur / Silke Gabriele Hack." München : Verlag Dr. Hut, 2011. http://d-nb.info/1014848482/34.
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Boukraa, Sadok. "Préparation, réactivité et étude des propriétés fongistatiques et immunostimulantes d'amino-2 thiazoles et d'imidazo-(2,1-B) thiazoles." Besançon, 1987. http://www.theses.fr/1987BESA2030.
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Le travail se divise en deux grandes parties : la premiere concerne la preparation d'aryl-6 imidazo(2,1-b) thiazoles substitues en 3 par des chaines de type acetate d'ethyle, aroylmethyle. (beta -hydroxy beta -aryl)ethyle te arylethyle. Pour ce faire, il a ete necessaire de preparer les amino-2 thiazoles corespondants substitues par ces memes chaines en 4 afin de las opposer a des acetophenones omega -bromees. L'influence des substituants presents est discutee en vue d'aprehender l'evolution des reactions. La seconde partie concerne des essais en tant que fongistatiques et/ou immunostimulants des composes preparees. Il ressort que les aminothiazoles sont plus interessants que les imidazothiazoles auusi bien sur l'inhibition de croissance de mycelium (epidermophyton) ou de germination des spores (candida, aspergillus) que sur la stimulation du lymphocyte t humain
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NASCIMENTO, André Augusto Pimentel Liesen. "Síntese e avaliação de atividades Anti-Toxoplama gondii e antimicrobiana de Tiossemicarbazidas, 4- Tiazolidinonas e 1,3,4-Tiadiazóis obidos a partir do Éster 5-Metil-1H-Imidazol-4-Carboxilato de Etila." Universidade Federal de Pernambuco, 2007. https://repositorio.ufpe.br/handle/123456789/3514.
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Previous issue date: 2007<br>Doenças parasitárias, como a toxoplasmose, afetam milhões de pessoas
no mundo inteiro e são amplamente pesquisadas. Este fato deve-se, em parte,
à elevada disseminação dessas doenças em pacientes imunocomprometidos,
principalmente naqueles que apresentam a síndrome da imunodeficiência
adquirida (AIDS). A toxoplasmose é uma infecção causada por Toxoplasma
gondii, parasita com biologia bastante complexa e de caráter cosmopolita,
estando largamente distribuído nas diversas áreas geográficas do globo
terrestre. Em trabalho publicado recentemente por nosso grupo de pesquisa, foi
observado que tiossemicarbazonas e aril-hidrazono-4-tiazolidinonas,
substituídas na porção aril com grupo nitro, possuem notória atividade anti-T.
gondii. Nos últimos anos, várias publicações têm abordado compostos
contendo o núcleo imidazol como potenciais agentes antiprotozoários.
Principalmente para análogos do megazol (2-amino-5-(1-metil-5-nitro-2-
imidazolil)-1,3,4-tiadiazol) atuando como agentes antichagásicos. Com o
objetivo de produzir novas moléculas ativas contra T. gondii desenvolvemos a
síntese e avaliação in vitro para aciltiossemicarbazidas (e seus derivados: 4-
tiazolidinonas e 1,3,4-tiadiazóis) obtidas a partir do éster etil(5-metil-1-Himidazol-
4-carboxilato). Aciltiossemicarbazidas foram sintetizadas através da
reação de adição entre 5-metil-1H-imidazol-4-carboidrazida e isotiocianatos
substituídos. A partir destas, foram obtidas duas novas séries: 4-tiazolidinonas,
através de uma reação tia-Michael envolvendo anidrido maléico como aceptor
de Michael; e 1,3,4-tiadiazóis por uma ciclodesidratação com ácido sulfúrico.
Os produtos finais foram purificados por recristalizações (tiossemicarbazidas) e
cromatografia em coluna (4-tiazolidinonas) em solventes apropriados, obtendose
rendimentos entre 10% e 94%, e caracterizados estruturalmente por
métodos espectroscópicos convencionais (RMN 1H, RMN 13C, IV) e
espectrometria de massas de alta resolução (MS-HR). A formação de
aciltiossemicarbazidas foi confirmada principalmente em RMN 13C, onde sinais
em 181,1-181,0 ppm e 163,1-162,5 ppm evidenciaram os grupos C=S e C=O,
respectivamente. Para 4-tiazolidinonas, bandas de absorção encontradas entre
1397-1378 cm-1, referentes à deformação angular do grupo NCS, confirmaram
o fechamento do anel. Os derivados 1,3,4-tiadiazóis foram caracterizados
observando-se a ausência de sinais entre 181,1-181,0 ppm e 163,1-162,5 ppm
em espectros de RMN 13C referentes aos grupos C=S e C=O. A existência de
troca química em aciltiossemicarbazidas, envolvendo átomos de H lábeis, foi
confirmada através da análise espectroscópica de troca química (EXSY). Os
resultados de atividade anti-T. gondii indicaram as aciltiossemicarbazidas e os
derivados contendo o núcleo 1,3,4-tiadiazol como os compostos de maior ação
inibitória frente à células vero infectadas e ao parasita intracelular, evidenciado
uma futura aplicação desses derivados como agentes anti-T. gondii. Por fim,
foram realizados testes antimicrobianos, os quais revelaram fracas atividades
dos compostos sintetizados frente a fungos e bactérias. A descrição de
atividades antimicrobianas na literatura, para compostos contendo os
heterociclos imidazol, 1,3,4-tiadiazol e 4-tiazolidinona, justificou a realização
dos testes para as moléculas obtidas
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Weiss, Andre. "Synthesen, Strukturen und Reaktivität von Imidazolyl- und Imidazol-boranen sowie von Diboryl- und Diboranyl(4)-porphyrinen." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965793702.
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García, de Miguel Cristina. "Entramats moleculars d'imidazoli-calix[4]arè." Doctoral thesis, Universitat de Barcelona, 2008. http://hdl.handle.net/10803/1640.
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Els entramats moleculars d'imidazoli-calix[4]arè constitueixen sistemes oligocatiònics macrocíclics amb un potencial atractiu en l'estudi de propietats a nivell supramolecular.<br/>Des de fa més de 20 anys la investigació en el nostre grup de reserca gira entorn de l'estudi de la química dels sistemes catiònics i oligocatiònics basats en sals d'imidazoli. Concretament, en la present Tesi Doctoral s'ha accedit a entramats moleculares d'imidazoli-calix[4]arè, la particular estructura química dels quals ha permés la formació de carbens N-heterocíclics (NHC), accedint, així, als nous complexos organometàl·lics de bis(carbè N-heterocíclic)-pal·ladi, a més, aquests darrers i els corresponents precursors, han estat valorats en reaccions d'acoblament creuat, essent la reacció de Suzuki-Miyaura seleccionada com a model, mostrant la seva eficiencia en front de cloro i bromoarens.<br/>Anàlogament, s'ha mostrat la seva capacitat en el reconeixement molecular d'anions, mitjançant el mètode de les titriacions per RMN de protó, i parells iònics, observant-se la cooperació en l'associació del parell iònic potassi-benzoat.<br/>Paral·lelament, s'ha sintetitzat una petita col·lecció de líquids iònics a temperatura ambient (RTILs) mitjançant un procediment innovador, basat en la utilització d'una resina de bescanvi iònic amb l'anió seleccionat mitjançant dos metodologies. Aquest estudi s'ha extès a altres sitemes catiònics i dicatiònics com són els derivats de bis(n-butilimidazoli)-calix[4]arè.<br><I>"IMIDAZOLIUM-CALIX[4]ARENE AS MOLECULAR FRAMEWORKS"<br/><br/>TEXT:<br/><br/>Imidazolium-calix[4]arene molecular scaffolds constitute oligocationics and macrocyclic compounds with a great potential towards the study of their own properties in Supramolecular Chemistry.<br/>For more than twenty years Prof. Ermitas Alcalde's research group has been working on the study of the chemistry of imidazolium-based frameworks. Specifically, in this Thesis we provide the synthesis of imidazolium-calix[4]arene molecular frameworks. Thanks to its own particular chemical structure, we have reported the synthesis of the bis(N-heterociclic carbenes) (NHC) as new bidentated ligands, carring out the preparation of the new bidentate palladium (II) complexes from the bis(imidazolium)-calix[4]arene salts. The Suzuki-Miyaura reaction was used to study their activity as catalyst, when they were prepared either in situ or from a well-defined complex, showing their effectiveness with chloro and bromoarenes.<br/>Analogously, as part of our ongoing research, we have described the anion binding properties of the dicationic bis(imidazolium) salts directly bonded to the upper rim of the calixarene structure then were studied by 1H NMR spectroscopic methods. In paralel, the hability of bis(imidazolium)-calixarene-crown-5 scaffold was examined in ion-pair binding. Remarkably, the cooperation effect in potassium-benzoate ion-pair binding of dicationic calix[4]arene-crown-5 was showed. <br/>On the other hand, a series of room temperature ionic liquids have been prepared by using an ion exchange resin with the anionic species selected by two methodologies. This study has been extended to another cationic and dicationic imidazolium frameworks as the bis(n-butylimidazolium)-calix[4]arene scaffold. </i>
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Cherouvrier, Jean-René. "Utilisation de la technologie micro-onde pour la préparation stéréocontrôlée de dérivés d'imidazolidin-4-ones : application à la synthèse d'imidazol-4-ones analogues de la leucettamine B." Rennes 1, 2002. http://www.theses.fr/2002REN10079.
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Les travaux présentés dans ce mémoire concernent la synthèse d’imidazol(idin)-4-ones, en particulier des analogues de la Leucettamine B. La première partie est consacrée aux rappels bibliographiques. La seconde partie concerne les résultats de nos travaux, premièrement nous décrivons la synthèse de la 3-méthyl-2-méthylsulfanyl-imidazol-4-one et la réactivité de son méthylène actif vis-à-vis notamment d’aldéhydes aromatiques, de cétones cyclisées et de cétones activées dans des réactions de Knoevenagel réalisées sans solvant en utilisant la technologie micro-onde. Le second chapitre est relatif à la synthèse de guanidines acycliques ou cycliques (2-amino-imidazolones) et décrit également nos résultats concernant la synthèse d’analogues de la Leucettamine B. Le dernier chapitre aborde la synthèse de dérivés d’imidazolidin-4-ones obtenus par réactions d’aminométhylènation qui sont ensuite utilisés dans des réactions de transamination avec diverses amines et sous irradiation micro-ondes.
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Ba, Lalla Aîcha Kirsch Gilbert. "Nouvelles approches vers la synthèse de l'acide 5-(2-oxo-2,3-dihydro-1H-thiéno[3,4-d]imidazol-4-yl) pentanoïque (tétradéhydrobiotine)." [S.l.] : [s.n.], 2007. ftp://ftp.scd.univ-metz.fr/pub/Theses/2007/Ba_Lalla.Aicha.SMZ0745.pdf.
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Mellino, Simona. "Synthetic and computational studies of group 3 and group 4 imido and hydrazido compounds." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:dcf036ac-263d-4c62-967c-c807fe1fe61e.
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This Thesis describes the synthesis and reactivity of titanium-nitrogen multiply bonded compounds. Mechanistic and bonding studies on titanium imido, hydrazido and borylimido complexes as well as on a novel scandium borylimide recently reported in our research group were described. <b>Chapter 1</b> provides an introduction to Group 4 and Group 3 metal-nitrogen multiply bonded compounds including synthesis, bonding and reactivity of titanium imido, hydrazido, alkylidene hydrazido and borylimido complexes, (L)Ti=NR, (L)Ti=NNR<sub>2</sub>, (L)Ti=NNCR<sub>2</sub> and (L)Ti=NBR<sub>2</sub>. <b>Chapter 2</b> describes the reactions of the hydrazido compound Ti(N<sub>2</sub> <sup>iPr</sup>N<sup>Me</sup>)(NNPh<sub>2</sub>)(py) with the Si - H and B - H bonds of silanes and boranes and with H<sub>2</sub>. The nature and mechanism of these reactions were investigated both computationally and experimentally. <b>Chapter 3</b> explores a series of new reactions and unprecedented transformations of organic boranes and silanes with titanium half-sandwich compounds. In addition, detailed mechanistic work, using DFT calculations, was performed to understand the chemistry behind these reactions. <b>Chapter 4</b> describes the bonding and reactivity of novel borylimido compounds. The systematic approach recently implemented in our research group to synthesise new titanium borylimido compounds, is described. A full computational study of the bonding of compounds with sandwich and half-sandwich structures is explained in detail. <b>Chapter 5</b> explores the experimental attempts to isolate the first scandium borylimido complex performed in our group. DFT and QTAIM and detailed mechanistic study are presented. <b>Chapter 6</b> contains experimental details, characterising data and DFT energies and coordinates of the optimized structures for the chemistry presented in Chapters Tw-Five.
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Harris, Cragin K. "Synthesis and Characterization of Five New Tetrakis(N-phenylacetamidato) Dirhodium(II) Amine Complexes and One Molybdenum Cofactor Described Crystallographically." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etd/2525.
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Six new crystal structures were determined using a Rigaku Mercurcy 375/MCCD(XtaLab mini) diffractometer. The structure of a molybdenum cofactor was solved resulting in an R1 (R1 = Σ ||Fo| - |Fc|| / Σ |Fo|) of 3.61% despite the presence of a disordered DMSO molecule. New Tetrakis(N-phenylacetamidato) Dirhodium(II) complexes were synthesized and characterized. Two 2,2-cis-[Rh2(NPhCOCH3)4]•(C3H4N2)x where x= 1 or 2 were successfully crystallized and solved with R1 values below 5%. Additional studies were conducted via NMR to observe formation of both products. Three potential catalysts were synthesized starting with 3,1-[Rh2(NPhCOCH3)4]. The resulting compounds were a mono adduct 3,1-[Rh2(NPhCOCH3)4]•(C3H4N2), and two dimer of dimers complexes with amine bridges 3,1-[Rh2(NPhCOCH3)4]2•(C8H6N2) and 3,1-[Rh2(NPhCOCH3)4]2•(C10H8N2). All three complexes were crystallized and solved with R1 values less than 10%. Additional NMR studies were conducted to elucidate solid and solution phase structures and to determine the possibility of additional amine bonds forming.
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Ba, Lalla Aïcha. "Nouvelle approche vers la synthèse de l'acide 5-(-2-oxo-2,3-dihydro-1H-thiéno[3,4-d]imidazol-4-yl) pentanoïque (la tétradéhydrobiotine)." Thesis, Metz, 2007. http://www.theses.fr/2007METZ045S/document.
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La biotine ou vitamine H est un coenzyme impliqué dans les processus de transfert de dioxyde de carbone sur diverses molécules naturelles. Sa très grande affinité avec l'avidine ou la streptavidine est couramment exploitée dans le cadre de différentes méthodes d'analyse biochimiques telles que la purification et la détection de protéines. Cependant cette affinité très élevée peut aussi constituer un inconvénient suivant l'utilisation recherchée car la rupture de l'interaction avidine-biotine-protéine d'intérêt implique des conditions de dénaturation drastiques peu compatibles avec l'obtention d’une protéine encore active. La préparation de nouveaux analogues de la biotine présentant une affinité modérée vis-à-vis de l’avidine et de la streptavidine pourrait permettre de faciliter la purification de protéine dans leur état natif. Dans cette optique et en collaboration avec l'équipe de biologistes de notre laboratoire, notre projet est de synthétiser un analogue de la biotine : la 2,3,4,5-tétradéhydrobiotine, puis d'évaluer l'interaction de ce composé avec l’avidine. Dans nos travaux nous avons isolé différents intermédiaires intéressants qui pourront être utilisés dans la synthèse de la tétradéhydrobiotine. Lors de cette étude nous avons également synthétisé de nouveaux thiéno[2,3-d]imidazolones substitués en position 5 au départ de l'hydantoïne<br>Intracellular biotin is a coenzyme in carbon dioxyde transport. Futhermore because of their high affinity, avidin-biotin or streptavidin-biotin coupling is often used in different biochemical analyses such as protein purification and detection. The high avidin/streptavidin-biotin affinity can also constitute a drawback since proteins require to be denaturated in order to be released, and therefore are often lacking activity. In order to identify pure and active proteins target using this methodology, our aim was to synthesize an analog of biotin: 2,3,4,5-tetradehydrobiotin. We have isolated different key intermediates for the synthesis of tetradehydrobiotin. During this study we also synthesize news thieno[2,3-d]imidazolones starting from hydantoin
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Mavric, Elvira. "Argininderivatisierung und 1,2-Dicarbonylverbindungen in Lebensmitteln." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2006. http://nbn-resolving.de/urn:nbn:de:swb:14-1145435031366-28110.
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Reaktion von Arginin mit Abbauprodukten 1,4-verknüpfter Disaccharide Im Verlauf der Reaktion von Arginin mit Abbauprodukten 1,4-glycosidisch verknüpfter Disaccharide entsteht ein Hauptderivatisierungsprodukt des Arginins, welches aus Inkubationsansätzen von Lactose mit N-(tert-Butoxycarbonyl)-L-arginin (Boc-Arg) bzw. N-a-Hippuryl-L-arginin (Hip-Arg) isoliert und als N-d-[5-(3-Hydroxypropyl)-4-oxo-imidazolon-2-yl]-L-ornithin (PIO) identifiziert werden konnte. PIO stellt ein spezifisches Reaktionsprodukt von Arginin mit Abbauprodukten 1,4-glycosidisch verknüpfter Disaccharide dar. Zum Nachweis des Precursors von PIO wurden die Bildung und der Abbau von 1,2-Dicarbonylverbindungen in Inkubationsansätzen von Lactose mit und ohne Hip-Arg nach der Hitzebehandlung mit o-Phenylendiamin untersucht. Es zeigte sich, dass ein als 1,2-Dicarbonylverbindung identifiziertes Abbauprodukt von Lactose nur in Abwesenheit von der Aminokomponente (Hip-Arg) als Hauptabbauprodukt bestimmbar war. Nach Isolierung dieser 1,2-Dicarbonylverbindung in Form ihres stabilen Chinoxalin-Derivates und der Strukturaufklärung ist es gelungen, dieses Hauptabbauprodukt der Lactose als (3'-Hydroxypropyl)-chinoxalin also das Chinoxalin der 3,4-Didesoxypentosulose (3,4-DDPs) zu identifizieren. Bestimmung von 1,2-Dicarbonylverbindungen in Lebensmitteln Glyoxal (GO), Methylglyoxal (MGO), 3-Desoxyglucosulose (3-DG) und 3-Desoxypentosulose (3-DPs) konnten nach Umsetzung mit o-Phenylendiamin erstmals in Milch- und Milchprodukten quantifiziert werden. Für Glyoxal wurden Gehalte von 0,06 bis 3,5 mg/ l und für Methylglyoxal von 0,2 bis 4,7 mg/ l bestimmt. 3-Desoxyglucosulose wurde mit Gehalten von 0,7 bis 3,5 mg/ l und 3-Desoxypentosulose von 0,1 bis 4,7 mg/ l bestimmt. Des Weiteren erfolgte die Bestimmung von Glyoxal, Methylglyoxal und 3-Desoxyglucosulose in käuflich erworbenen deutschen Honigen, in Honigen des Imkerverbandes Dresden und in neuseeländischen Honigen. Im Vergleich zu den Milchprodukten wurden deutlich höhere Gesamtgehalte an 1,2-Dicarbonylverbindungen (124 bis 1550 mg/ kg) bestimmt. Für 3-Desoxyglucosulose wurden 119 bis 1451 mg/ kg, für Glyoxal 0,2 bis 4,6 mg/ kg und für Methylglyoxal 0,5 bis 743 mg/ kg ermittelt. Ein Zusammenhang zwischen hohen Gehalten an 1,2-Dicarbonylverbindungen und der antibakteriellen Aktivität der Honige wurde untersucht. Hier stellten die neuseeländischen Manuka-Honige (Manuka: Leptospermum scoparium, Teebaum) den Schwerpunkt der Untersuchung dar. Für die untersuchten Manuka-Honige konnten ungewöhnlich hohe Gehalte an Methylglyoxal bestimmt werden (von 347 bis 743 mg/ kg). Von 12 verschiedenen Honigen deutscher und neuseeländischer Herkunft konnten nur Manuka-Honige als antibakteriell wirksam eingestuft werden. Bezogen auf den Gehalt an Methylglyoxal liegen die MIC-Werte für Staphylococcus aureus bei 1,5 mmol/ l für Manuka-Honig (35 % v/v), 1,4 mmol/ l für Manuka-Honig &quot;active&quot; (30 % v/v), 1,1 mmol/ l für Manuka-Honig UMF 10+ (25 % v/v) bzw. 1,8 mmol/ l für Manuka-Honig UMF 20+ (20 % v/v). Es zeigte sich, dass die antibakterielle Aktivität des Honigs unmittelbar auf den Methylglyoxal-Gehalt zurückführbar war.
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Seeyangnok, Samitthichai. "NOVEL SYNTHESIS OF DERIVATIVES OF 1,2-DIIMIDAZOLYL-BENZENE AND THEIR SILVER CARBENE COMPLEXES." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1191506703.
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Liu, Yang Glaser Rainer. "Variable-temperature ¹H-NMR and AB initio study of 5-amino-imidazole-4-carboxamide (AICA) competing paths for amide-H scrambling /." Diss., Columbia, Mo. : University of Missouri--Columbia, 2008. http://hdl.handle.net/10355/6281.
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Title from PDF of title page (University of Missouri--Columbia, viewed on Feb. 18, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dr. Rainer Glaser, Thesis Supervisor. Includes bibliographical references.
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Deschamps, Jérôme. "Diacétylènes à fonctionnalités imidazole ou imidazolium : nouveaux polydiacétylènes rouges analogues du poly-1, 6-bis(N,N-diphénylamino)-2, 4-hexadiyne." Montpellier 2, 2007. http://www.theses.fr/2007MON20210.
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Macchi, Fernanda Souza. "3,4-diidroquinazolin-4-onas e 1H-benzo[d]imidaz?is : planejamento utilizando hibrida??o molecular, s?ntese e atividade inibit?ria sobre o crescimento de Mycobacterium tuberculosis." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2017. http://tede2.pucrs.br/tede2/handle/tede/7818.
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Previous issue date: 2017-11-22<br>Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES<br>Using the classical hybridization approach series of 1H-benzo[d]imidazoles and 3,4-dihydroquinazolin-4-ones were synthesized and evaluated as inhibitors of Mycobacterium tuberculosis growth. Chemical modifications and structure-activity relationship studies yielding potent antitubercular agents with minimum inhibitory concentration values in submicromolar range. Further, the synthesized compounds were active against drug-resistant strains and were devoid of apparent toxicity to HepG2, HaCat, and Vero cells. In addition, some 3,4-dihydroquinazolin-4-ones showed low risk of cardiac toxicity, no signals of neurotoxicity or morphological alteration in zebrafish (Danio rerio) models. Therefore, these data denote that this class of molecules may furnish candidates for future development of novel anti-TB drug alternatives.<br>Usando a abordagem cl?ssica de hibrida??o molecular, s?ries de 1H-benzo[d]imidaz?is e 3,4-diidroquinazolin-4-onas foram sintetizadas e ensaiadas como inibidores de crescimento de Mycobacterium tuberculosis. Modifica??es qu?micas e estudos de rela??o estrutura-atividade nos conduziram a potentes agentes antituberculose com valores submicromolares de concentra??o inibit?ria m?nima. Os compostos sintetizados tamb?m foram ativos contra cepas resistentes ? f?rmacos e demonstraram desprovida citotoxicidade aparente em c?lulas HepG2, HaCat e Vero. Al?m disso, algumas 3,4-diidroquinazolin-4-onas apresentaram baixo risco de toxicidade card?aca, e nenhum sinal de neurotoxicidade ou altera??o morfol?gica em modelo de peixe-zebra (Danio rerio). Sendo assim, os resultados indicam que essa classe de mol?cular pode fornecer condidatos para o desenvolvimento futuro de novos f?rmacos contra a tuberculose.
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Potvin, Marie-Eve. "Évaluation d'inhibiteurs au TGF-[bêta]1 chez la lignée cellulaire gliale maligne F98." Mémoire, Université de Sherbrooke, 2007. http://savoirs.usherbrooke.ca/handle/11143/3906.
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La protéine du TGF-[bêta]1 est une protéine multifonctionnelle qui agit dans plusieurs types cellulaires. Son action varie selon le type de cellulaire. Bien qu'elle ait un rôle inhibiteur chez les astrocytes normaux, elle posséderait un rôle principalement activateur de nombreuses voies carcinogéniques chez les tumeurs astrocytaires primaires malignes. L'isoforme du TGF-[bêta]1 est celle qui est la plus impliquée dans ces processus. Elle joue un rôle dans l'activation des voies d'invasion tissulaire et d'angiogenèse, mais inhibe des mécanismes d'apoptose et d'immunosuppression.La présente étude vise à évaluer l'effet de l'inhibition de la protéine du TGF-[bêta]1 sur le modèle cellules de glioblastome F98/Fischer sur la prolifération et la migration cellulaire. Pour ce faire, un inhibiteur sélectif au récepteur a d'abord été utilisé. Par la suite, des techniques d'inhibitions nucléotidiques (oligoantisens, siRNA, shRNA) ont été testées. Nous avons d'abord validé l'utilisation du modèle F98/Fischer dans l'étude des fonctions du TGF-[bêta]1 et de l'inhibition de la production de cette protéine. Nous avons observé la production importante de TGF-[bêta]1 par les cellules F98 avec des essais immunologiques (Western, ELISA). Avec l'essai ELISA, nous avons observé la production considérable de TGF-[bêta]1 actif d'emblée.La présence de notre protéine d'intérêt a été détectée dans le cerveau de rat Fischer implanté avec les cellules F98 contrairement aux animaux sains qui ne montrent aucune trace de TGF-[bêta]1. Ensuite, nous avons tenté de mettre au point une approche nucléotidique pour inhiber la production du TGF-[bêta]1. Pour les oligoantisens et les siRNA qui ont été couplés avec le vecteur liposomale Metafecten, nous n'avons pas réussi à obtenir de diminution significative du TGF-[bêta]1 dans les surnageants des cultures de F98 . Pour l'approche au shRNA/lentivirus, nous n'avons pas réussi à former de bactéries contenant la construction recherchée. Par la suite, nous avons testé sur notre modèle cellulaire un inhibiteur pharmacologique sélectif, le SB-431642, du récepteur permettant la phosphoryllation de la voie instracellulaire Smad, le T[bêta]R-I. Les essais de prolifération (WST-1) ont permis de constater un ralentissement dans la croissance des F98 traitées au SB-431542. Un essai immunologique western a permis de constater que la production de VEGF était d'ailleurs influencée par cette inhibition du TGF-[bêta]1. L'utilisation d'un vecteur luciférase couplé à un élément de réponse Smad a permis de constater que la voie du TGF-[bêta]1 était bel et bien affectée à la baisse par cet inhibiteur. En effet, le dosage luminescent de la luciférase a permis de noter une diminution significative de sa quantité. L'activité d'un tel vecteur est proportionnelle à l'activité Smad intracellulaire. Nous avons aussi testé cet inhibiteur sur le modèle de croissance tumorale tridimensionnelle de sphéroïdes F98.La croissance des sphéroïdes a été ralentie par la présence de l'inhibiteur et l'invasion de la matrice de collagène observée chez les sphéroïdes contrôles a été freinée par l'ajout de SB-431542. Bien que certains de nos essais n'aient pas donné les résultats escomptés, l'utilisation de l'inhibiteur SB-431542 nous a permis de voir l'implication à du TGF-[bêta]1 dans les mécanismes de progression tumorale chez la lignée cellulaire F98, tel que la prolifération et la migration cellulaire. Ces résultats sont le préalable à d'éventuels essais avec le modèle d'étude animal, le rat Fischer avec l'utilisation de cellules de glioblastomes F98.
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Casale, Mariana Romano Camilo. "Desenvolvimento de processos químicos seguindo os princípios adotados pela química verde: redução e conversão de CO2 usando compostos de Mn(I)." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/6319.
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Previous issue date: 2014-10-09<br>Universidade Federal de Minas Gerais<br>Due to its versatile chemistry and ability to stabilize metals with low oxidation states, carbonyl compounds of transition metals play an important role in various fields of organometallic chemistry. In our research group, we have studied carbonyl compounds of manganese (I) over time and investigated their photochemical and spectroscopic properties. We carried out studies in photochemistry, electrochemistry (cyclic voltammetry and spectroelectrochemistry accompanied by UV-Vis and IR) and photoinduced intermolecular electron transfer (ET) reactions (with the electron acceptor MV2+, methylviologen) for the compound fac- [Mn(phen)(CO)3(4MeImH)](SO3CF3) (fac-1) where phen = 1,10-phenanthroline, 4MeImH = 4-methyl-imidazol and SO3CF3 = triflate ion, compound already synthesized and processed by the group. fac-1 shows electronic absorption bands in the UV-Vis at 380 (MLCT) and 270 nm (LLCT) in CH3CN and intense bands in IR between 2200 and 1800 cm-1, consistent with the facial arrangement of the three CO ligands in the sphere of coordination of the metal. The complex is stable in solid state and is a mixture of two isomers while in solution, the adjacent (A) and remote (R) isomers relative to the nitrogen atom (N) of the 4MeImH ligand which coordinates to the metal Mn. Encouraged by the results obtained by the group before, in which the compound fac-1 under irradiation of light in aqueous solution and in the absence of oxidizing agents in the reaction medium was able to cleave a molecule of water to produce molecular oxygen (O2) detected by a Clark electrode, we investigated the reduction and conversion of carbon dioxide molecules (CO2) to CO using this compound of Mn in organic solution, by photochemical and electrochemical means in N2 and CO2 atmosphere. Through the development of chemical processes, the petrochemical industry has made great contributions to mankind but at the same time the release of large amounts of CO2 in the atmosphere has harmed the environment. Capturing this gas emitted into the atmosphere primarily by the burning fossil fuels is a necessary strategy to minimize the greenhouse effect. In our photochemical studies, the complex was able to reduce CO2 to CO, product detected by 13C NMR (185 ppm), and the mechanisms of photochemical and electrochemical reactions of fac-1 in the presence of CO2 were checked. We carried out DFT calculations to corroborate experimental data and the results show the agreement of the UV-Vis and IR spectrum for the proposed product. A comparison of results shows the importance of ligand 4MeImH in the multiple photoinduced electron transfer reactions assisted by protons and the great potential of the fac-1 compound to participate in photocatalytic processes of interest, such as the reduction and conversion of CO2 to products of interest to the chemical industry.<br>Devido a sua química versátil e habilidade em estabilizar metais com baixos estados de oxidação, os complexos carbonílicos de metais de transição desempenham um papel importante em vários campos da química organometálica. No nosso grupo de pesquisa complexos carbonílicos de manganês (I) vêm sendo estudados ao longo do tempo e suas propriedades espectroscópicas e fotoquímicas investigadas. Neste trabalho estudos fotoquímicos, eletroquímicos (voltametria cíclica e espectroeletroquímica acompanhada por UV-Vis e IV) e de reações de transferência de elétrons (TE) intermoleculares fotoinduzidas (com o receptor de elétrons MV2+, metilviologênio) foram realizados para o complexo fac- [Mn(phen)(CO)3(4MeImH)](SO3CF3) (fac-1) em que phen = 1,10-fenantrolina, 4MeImH = 4-metil-imidazol e SO3CF3 = íon triflato, complexo já sintetizado e caracterizado pelo grupo. fac-1 apresenta bandas de absorção eletrônica no UV-Vis em 380 (MLCT) e 270 nm (LLCT) em CH3CN e bandas intensas no IV entre 2200 e 1800 cm-1, consistentes com o arranjo facial dos três ligantes CO na esfera de coordenação do metal. O complexo é estável no estado sólido e em solução e se apresenta como uma mistura de dois isômeros, o adjacente (A) e o remoto (R) em relação ao átomo de nitrogênio (N) do ligante 4MeImH que se coordena ao metal Mn. Estimulados pelos resultados anteriormente obtidos pelo grupo em que o complexo fac-1 sob irradiação de luz em solução aquosa e na ausência de agentes oxidantes no meio reacional foi capaz de clivar a molécula de água produzindo oxigênio molecular (O2) detectado por eletrodo de Clark, nesta etapa do nosso trabalho investigamos a redução da molécula de gás carbônico (CO2) a CO usando o complexo de Mn em solução orgânica, por via fotoquímica e eletroquímica em atmosfera de N2 e CO2. Através do desenvolvimento de processos químicos, a indústria petroquímica tem realizado grandes contribuições para a humanidade, mas ao mesmo tempo, a liberação de grandes quantidades de CO2 na atmosfera tem prejudicado o ambiente. A captura deste gás, emitido principalmente pela queima de combustíveis fósseis, é uma estratégia necessária para minimizar o efeito estufa. Nos nossos estudos fotoquímicos, o complexo foi capaz de reduzir CO2 a CO, produto detectado por RMN 13C em 185 ppm, e os mecanismos das reações fotoquímicas e eletroquímicas na presença de CO2 foram averiguados. Cálculos computacionais do tipo DFT foram realizados para corroborar os dados experimentais e os resultados mostram a concordância nos espectros de UV-Vis e IV para os produtos propostos. A comparação dos resultados mostra a importância do ligante 4MeImH nas reações fotoinduzidas de transferência de elétrons múltiplas assistidas por prótons e o grande potencial do complexo fac-1 em participar de processos fotocatalíticos de interesse, como a conversão do CO2 a produtos de interesse da indústria química.
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Tholé, France. "Étude d'une synthèse totale énantiosélective et convergente des liposidomycines." Paris 6, 2002. http://www.theses.fr/2002PA066352.
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Renaud, Jean-Paul. "Oxydations d'alcanes et d'alcènes par des systèmes métalloporphyriniques modelés du cytochrome P-450." Paris 6, 1986. http://www.theses.fr/1986PA066139.
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La synthèse d'une pophyrine de fer à "anses de panier" chirale comportant des aminoacidés de configuration déterminée est décrite. On a étudié sa pureté optique et sa conformation en solution. Dans une deuxième partie on décrit un nouveau système oxydant catalytique utilisant l'eau oxygénée en présence d'une porphyrine de manganèse et d'imidazole permettant la conversion quantitative d'alcènes en époxydes et d'alcanes en alcools et cétones.
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Procházková, Martina. "Monitoring imidazolů ve vybraných druzích nápojů." Master's thesis, 2019. http://www.nusl.cz/ntk/nusl-427645.
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The diploma thesis deals with monitoring imidazoles in selected types of beverages. The aim is to detect imidazoles in drinks by High Performance Liquid Chromatography with the use of Mass Spectrometry (HPLC-MS/MS). The coumpounds that were detected are 2-Methylimidazole, 4-Methylimidazole and 2-Acetyl-4(5)-(1,2,3,4-tetrahydroxybutyl)-imidazole. The theoretical part concerns the origin of imidazoles, its occurrence and influence on human health. There is also a brief introduction to technology of production of beverages containing imidazoles. The practical part statistically compares imidazoles concentration amongst separated types of dark beers, cola beverages, coffee beans and instant coffees. The end of the thesis focuses on determining a dependency of imidazoles on roast time in Ethiopia coffee beans.
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Gabriel, Carla Patrícia Morais Sequeira. "Atividade antimicrobiana de derivados da 5-amino-imidazol-4-carboxamidrazona." Master's thesis, 2014. http://hdl.handle.net/10284/6233.
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Nas últimas décadas as infeções fúngicas têm-se tornado uma das principais causas de infeções hospitalares nos países desenvolvidos. Vários fatores, como a Síndrome da Imunodeficiência Adquirida (SIDA), a neutropenia associada à quimioterapia anti-tumoral ou a imunossupressão induzida por fármacos, têm contribuído para o aumento das infeções fúngicas sistémicas oportunistas. Para além disso, as infecções fúngicas são um problema não apenas para indivíduos imunocompremetidos mas também para indivíduos saudáveis, devido ao aparecimento de estirpes multirresistentes. Por esta razão, as doenças fúngicas são actualmente consideradas um problema grave em todo o mundo. Neste sentido é importante a pesquisa e o desenvolvimento de novos antifúngicos de forma a melhor a eficácia das terapias convencionais.
O objectivo deste trabalho consistiu na: (i) avaliação da atividade antibacteriana e antifúngica de derivados da 5-amino-imidazol-4-carboxamidrazona, a sua relação estrutura actividade e elucidação do seu possível mecanismo de ação; (ii) determinação do efeito dos melhores compostos no sistema imune; (iii) avaliação da atividade destes sobre a formação de biofilme bem como contra biofilmes pré-estabelecidos, em substratos de nanohidroxiapatite.
Os resultados obtidos demonstraram que os compostos estudados têm uma atividade muito limitada em Staphylococcus aureus, Pseudomonas aeruginosa e Escherichia coli, mas são, no geral, providos de atividade antifúngica. Pela comparação das atividades em Candida albicans, C. krusei, C. parapsilosis e Cryptococcus neoformans foi possível, com base na relação estrutura/atividade, selecionar três compostos líderes, as (Z)-5-amino-N'-aril-1-metil-1H-imidazol-4-carbohidrazonamidas: [aril= fenil (2h), 4-fluorofenil (2k), 3-fluorofenil (2l)].
Os derivados de imidazol 2h, 2k e 2l inibiram fortemente o crescimento de C. krusei e C. neoformans embora a sua atividade em fungos filamentosos tivesse sido baixa quando comparado com a atividade em leveduras. Para além disso é de salientar a atividade fungicida dos compostos 2h e 2k contra C. krusei. No que se refere ainda ao mecanismo de ação antifúngica, 2h, 2k e 2l inibiram a atividade mitocondrial de C. krusei enquanto apenas o composto 2k foi capaz de o fazer quando se tratava de C. albicans. O composto 2h foi ainda capaz de inibir significativamente a transição dimórfica sendo que a formação do tubo germinativo é um importante fator de virulência de C. albicans.
Relativamente à atividade no sistema imune, estes compostos apresentaram um efeito inibidor da proliferação de células mononucleares humanas estimuladas por fitohemaglutinina e da produção de óxido nítrico (NO) pela linha celular de macrófagos de ratinho RAW 264.7, após estimulação por Lipopolissacarídeo (LPS).
Para além disso verificou-se uma acentuada redução na formação do biofilme por C. albicans e C. krusei em nanohidroxiapatite (nanoHA) particularmente para o composto 2l.
Em conclusão estes compostos mostraram ter potencial para futura aplicação no tratamento de micoses provocadas por Candida sp e C. neoformans bem como no tratamento ou prevenção de infecções fúngicas associadas a dispositivos médicos. Além disso, podem permitir o desenho de novas estratégias para prevenção/tratamento de micoses oportunistas em doentes recetores de transplantes.<br>In the last decades fungal infections have become one major cause of nosocomial infections in developed countries. Several factors, such as Acquired Immunodeficiency Syndrome (AIDS), neutropenia associated with anti-tumour chemotherapy or drug-induced immunosuppression have contributed to the increase in systemic fungal opportunists infections. Furthermore, fungal infections are a problem not only for immunocompromised patients but also for healthy individuals due to the appearance of multi-resistant strains. For this reason, fungal diseases are now considered a serious problem worldwide. In this regard it is important the research and development of new antifungal drugs to improve the effectiveness of conventional therapies.
The aim of this work consisted in the: (i) evaluation of the antibacterial and antifungal activity of 5-aminoimidazole-4-carboxamidrazones derivates, the structure/activity relation and elucidation of its possible mechanism of action; (ii) determination of the effect of best compounds on the immune system; (iii) evaluation of the activity of these in biofilm formation as well as against pre-established biofilms in nanohydroxyapatite (nanoHA) substrates.
The results demonstrate that the studied compounds have very limited activity in Staphylococcus aureus, Pseudomonas aeruginosa e Escherichia coli, but in general are provided of antifungal activity. By comparing the activities in Candida albicans, Candida krusei, Candida parapsilosis, Cryptococcus neoformans was possible, based on the structure/activity relation, select three leader compounds , (Z)-5-amino-N'-aryl-1-methyl-1H-imidazole-4-carbohydrazonamides [aryl = phenyl (2h), 4-fluorophenyl (2k), 3-fluorophenyl (2l)]. The imidazole derivatives 2h, 2k 2l strongly inhibited the growth of C. krusei and C. neoformans, although their activity in filamentous fungi have been low when compared to the activity in yeasts. Moreover is to point out the fungicidal activity of the compounds 2h and 2k against C. krusei. As regards to the mechanism of antifungal action , 2h, 2k and 2l inhibited the mitochondrial activity of C. krusei while only 2k compound was able to do so when it came to C. albicans.
Compound 2h was able to significantly inhibit the dimorphic transition, being that the germ tube formation is an important virulence factor of C. albicans.
Regarding the activity on the immune system, these compounds had an inhibitory effect on human mononuclear cells proliferation stimulated by phytohemagglutinin and in the nitric oxide (NO) production by the macrophage cell line RAW 264.7 mice after lipopolysaccharide stimulation.
Furthermore there was a marked reduction in biofilm formation by C albicans and C krusei in nanoHA particularly for compound 2l.
In conclusion these compounds demonstrated to have potential for future application in the treatment of fungal infections caused by C. neoformans and Candida sp as well as in the treatment or prevention of fungal infections associated with medical devices. Moreover, may allow the development of new strategies for prevention / treatment of opportunistic mycoses in transplanted patients.
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Thiverny, Maryse, Pierre Yves Chavant, and Véronique Blandin. "1-OXY-2,3-DIHYDRO-IMIDAZOL-4-ONES : DES INTERMEDAIRES ET DES CIBLES." Phd thesis, 2010. http://tel.archives-ouvertes.fr/tel-00526669.
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Les travaux présentés s'articulent autour de synthons nitrone de type N-oxy-imidazolidinone, pour lesquels nous avons exploré les applications possibles. Nous avons développé une nitrone achirale, CYCNO, accessible en 3 étapes depuis un ester de la glycine (66%) et une nitrone chirale, MiPNO. Celle-ci a été obtenue sous forme énantiopure par une méthode de résolution nouvelle ; chaque énantiomère est ainsi accessible avec des rendements de 15 et 17% depuis l'ester de la glycine. CYCNO a été utilisée comme modèle pour étudier la réactivité des N-oxy-imidazolidinones vis-à-vis des halogénures d'aryl- et hétéroarylmagnésium, préparés par insertion de magnésium ou par échange iode-magnésium. La réoxydation des hydroxylamines intermédiaires mène à une nouvelle série de nitrones, pouvant être utilisées comme pièges à radicaux libres. MiPNO a été utilisée pour la préparation d'acides aminés non naturels, arylglycines et α-aryl,α-méthylglycines. La séquence met en jeu une réaction d'addition d'organomagnésiens totalement diastéréosélective. Sept cibles arylglycines ont été préparées. De plus, des réactions de cycloaddition 1,3-dipolaire entre MiPNO et différents alcènes ont conduit à des isoxazolidines, obtenues de façon hautement régio- et diastéréosélective. Le cycloadduit peut être converti en l'α-amino-γ-lactone correspondante en une seule opération, ce qui a mené à la préparation d'un nouveau γ-hydroxy-α-amino-acide énantiopur.
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Lyssenko, Alexei [Verfasser]. "Synthese der Alkaloide Botryllazin B und (4-Hydroxyphenyl)-[4-(4-hydroxyphenyl)-1H-imidazol-2-yl]methanon sowie Synthese von Brevicollinderivaten / Alexei Lyssenko." 2004. http://d-nb.info/970165749/34.
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Weiß, André [Verfasser]. "Synthesen, Strukturen und Reaktivität von Imidazolyl- und Imidazol-boranen sowie von Diboryl- und Diboranyl(4)-porphyrinen / vorgelegt von Andre Weiß." 2002. http://d-nb.info/965793702/34.
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顏學仁. "Synthesis and biological activity of naphtho [ 2, 3-d] imidazole-4, 9-dione and its related compounds." Thesis, 1987. http://ndltd.ncl.edu.tw/handle/95205513988626943862.
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Sung, Chien-wei, and 宋建緯. "Synthesis, Crystal structure and properties of Metal coordination polymers with 2,5-bis(4'-(imidazol-1-yl)benzyl)-3,4-diaza-2,4-hexadiene." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/25314573833346026316.
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Lee, Mung-Shung, and 李孟玹. "Synthesis, Crystal structure and thermal ability of Metal coordination polymers with 2,5-bis(4’-(imidazol-1-yl)benzyl)-3,4-diaza-2,4-hexadiene." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/42088008515033830135.
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Liu, Yuan, and 劉媛. "The anti-proliferation effect of 2-(Naphthalen-2-ylmethylsulfanyl)-5,5-diphenyl-1,5-dihydro-imidazol-4-one（SDil-N10）in human vascular endothelial cells." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/27079856038903848465.
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碩士<br>臺北醫學大學<br>醫學研究所<br>92<br>The aim of this study was to examine the anti-proliferation effect of 2-(Naphthalen-2-ylmethylsulfanyl)-5,5-diphenyl-1,5-dihydro- imidazol-
4-one (SDil-N10), an analogue of antiepileptic drug phenytoin(5,5- diphenylhydantoin, DPT), on human umbilical vein endothelial cells (HUVEC) and its possible molecular mechanism underlying. SDil-N10 at a range of concentrations (10-50 uM) dose- and time-dependently inhibited DNA synthesis and decreased cell number in cultured HUVEC, but less effect in human fibroblasts. [3H] Thymidine incorporation assay demonstrated that treatment of HUVEC with SDil-N10 arrested the cell at the G0/G1 phase of the cell cycle. Western blot analysis revealed that the protein levels of p21 and p27 increased and cyclin A decreased after SDil-N10 treatment. In contrast, the protein levels of p53, cyclin D1, D3 and E, cyclin-dependent kinase (CDK2, and CDK4) in HUVEC were not changed significantly after SDil-N10 treatment. Immunoprecipitation showed that the formation of the CDK2-p21 complex, but not the CDK4-p21, CDK2-p27 and CDK4-p27 complex, was increased in the SDil-N10-treated HUVEC. Kinase assay further demonstrated that CDK2, but not CDK4, kinase activity was decreased in the SDil-N10-treated HUVEC. SDil-N10 also inhibited vascular endothelial growth factor (VEGF) induced endothelial cells proliferation. 2D-Matrigel and rat aorta tube formation assays further showed that SDil-N10 inhibited HUVEC tube formation. Taken together, these data suggest that SDil-N10 inhibits HUVEC proliferation by increasing the level of p21 protein, which in turn inhibits CDK2 kinase activity, and finally interrupts the cell cycle. The findings from the present study suggest that SDil-N10 might have the potential to inhibit the occurrence of angiogenesis.
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Po-YangCheng and 程伯揚. "Performance Study of Polybenzimidazole Membranes and 1H-imidazole-4-sulfonic acid /Polybenzimidazole Hybrid Membranes for High Temperature Proton Exchange Membrane Fuel Cells." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/82974756431403841138.
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碩士<br>國立成功大學<br>材料科學及工程學系<br>104<br>In this work, sulfonated organic compound, 1H-imidazole-4-sulfonic acid (ImSA), and fluorine-containing polybenzimidazole (6F-PBI) were synthesized. A series of pristine PBI membranes and ImSA-PBI hybrid membranes were prepared. We expected that adding ImSA molecules into PBI membranes could improve the proton conductivity. The pristine PBI membranes and ImSA-PBI hybrid membranes properties for HT-PEMFC have been study. Adding ImSA molecules slightly reduced the properties of membrane but improved the acid doping level and proton conductivity. The proton conductivity of ImSA-PBI hybrid membrane could reach 0.28 S/cm at 170 oC. We fabricated membrane electrode assemblies (MEA) with pristine PBI membranes and ImSA-PBI hybrid membranes. In the single cell test, the max power density at current density of 1.2 A/cm2 were 540 and 610 mW/cm2 for pristine PBI membrane and ImSA-PBI hybrid membrane, respectively. We conducted a startup-shutdown test (operated at 160 oC with 0.2 A/cm2 for 12 h and then 12 h off at room temperature) and a 30 days steady-state test (150 oC with 0.2 A/cm2 ). There was no degradation for both pristine PBI membrane and ImSA-PBI hybrid membrane, but we found that ImSA-PBI hybrid membrane had more phosphoric acid loss during operation.
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Wu, Wei-chie, and 吳偉傑. "Intramolecular Imidate-Amide Rearrangement of 2-Substituted 4-(-Chloroalkoxy)quinazoline Derivatives. 1,3 -O → N Shift of Chloroalkyl Groups via Cyclic 1,3-Azaoxonium Intermediates." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/3a2p3s.
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碩士<br>靜宜大學<br>應用化學研究所<br>97<br>The alkylation of 2-substituted 4-(-chloroalkoxy)quinazoline derivatives gave the N- and O-alkylation products. However the O-alkylation products were transferred to the N-alkylation products through 1,3 -O→N shift in less a day. The mechanism is different from Chapman rearrangement because the reactants have leaving groups. The intermediate of the 1,3-O→N shift is hard to be trapped, so computational chemistry was used to explore the mechanism of the 1,3 -O→N shift. The optimized structures of 2-substituted 4-(-chloroalkoxy) quinazoline, 3-(-chloroalkyl)quinazoline-4(3H)-one and 1,3- azaoxonium were obtained with B3LYP(d)/6-31G(d). The NBO calculation and energy barrier show that 1,3-azaoxonium intermediates prefer to break the O-C bond because of lower energy barrier. The transition states of the 1,3-O→N shift were also located. The 1,3-O→N shift was proceeded by an intramolecular two-step mechanism via five- and six-membered 1,3-azaoxonium intermediates. First, 4-(- chloroalkoxy)quinazoline became the cyclic 1,3-azaoxonium and then chloride ion attacked the carbon which has lower electron density. The cyclic step is the rate-determining step. The higher basis set 6-311G(d,p) did not give satisfied results. The reason might be the solvent effect.