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Gollins, David William. "The use of 2-azetidinone-4-carboxylic acid as a chiral synthon." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386889.
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ABBIATI, GIORGIO. "Reazioni di cicloaddizione tra 1,3-diazabuta-1,3-dieni e cheteni:sintesi di diidropirimidinoni e 4-immino-azetidinoni." Doctoral thesis, Università degli Studi di Milano, 2000. http://hdl.handle.net/2434/651275.
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The work of this Ph.D. thesis is an in depth study on [4+2] and [2+2] cycloaddition reactions of 1-(4-methylphenyl) and 1-benzyl-1,3-diaza-1,3-butadienes with different ketenes, usually generated from the corresponding acid halide in the presence of a base. Reaction with phenyl, diphenyl, chloro and ethoxycarbonylketenes are described and the mechanism involved is discussed. Moreover, thermal and photochemical ring expansion reactions of azetidinones to 5,6-dihydro-3H-pyrimidin-4-ones are studied. Finally, the [2+2] cycloaddition reactions of 1-benzyl-2,4-diphenyl-1,3-diaza-1,3-butadiene with some chiral ketenes, such as beta-(dimethylphenylsilyl)ketene, beta-menthoxyketene and Evans-Sjögren ketene are investigated. The results are analysed and rationalized also on the basis of computational calculations.
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Burtoloso, Antonio Carlos Bender. "3-azetidinonas e 3-azetidinois : preparação e aplicações na sintese de azetidinas substituidas." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249762.
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Orientador: Carlos Roque Duarte CorreiaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Doutorado
Quimica Organica
Doutor em Ciências
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Murphy, Deirdre M. "STUDIES OF THE METALLO BETA LACTAMASE CCrA FROM BACTERIODES FRAGILIS AND A DANSYLATED MONOCYCLIC BETA LACTAM (1-(5-DIMETHYLAMINO-1-NAPTHALENESULFONYL HYDRAZIDO)-3-ACETAMIDO-4-METHOXY-2-AZETIDINONE." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin990561318.
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Sharma, Madan Kumar. "Approaches to 3,3-disubstituted azetidinones." Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5577.
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Chapter 1 contains a very brief overview of 3,3-disubstituted azetidinones. Also included in this chapter are the approaches to 'hybrid' azetidinones, i.e. those which contain the structural features of more than one class of azetidinones. Finally the target molecules for the present studies are listed. Chapter 2 contains details of use of various 2,3-dihydroxybutyric acid derivatives in enantioselective syntheses of 3-alkoxyazetidinones with an additional substituent at position 3. In chapter 3 similar studies on threonine derivatives for the syntheses of 3-amino-3-hydroxyethylazetidinones are described. These studies were only partially successful. In chapter 4 a systematic approach towards the syntheses of 3-alkoxyazetidinones is described. The steps involved were the formation of the C-3 carbanion from the parent azetidinones, reaction with acetaldehyde, oxidation of the resulting 3-alkoxy-3-hydroxyethylazetidinones and finally the reduction of the acetyl compound in a non-chelation controlled manner. It has been possible to synthesize protected 3-amino-3-hydroxyethylazetidinones by a similar series of reaction and the results are presented in chapter 5. Chapter 6 has details of syntheses of 3-hydroxy, 3-hydroxy-3-hydroxyethyl, 3-hydroxy-3-allyl and 3-$\sp\prime$epoxy$\sp\prime$azetidinones. Chapter 7 contains results of a detailed study on the impact of various variables on the non-chelation controlled reduction of 3-acylazetidinones (which have an additional substituent at 3-position). Chapter 8 is about the use of N, N-dimethylchloromethylenimnium chloride for the purpose of activating carboxylic acids for their final conversion to azetidinones. An attempt was made to determine the nature of the white solid obtained on reaction of DMF with oxalyl chloride, and the product of reaction between this white solid and a carboxylic acid.
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Pearson, Christopher I. "Lithiated azetidine and azetine chemistry." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:cf3c942f-80de-4092-a38d-11006ccbb9ce.
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This work describes developments in new azetidine and azetine chemistry; specifically, methods developed for the introduction of functionality α- to nitrogen in both ring systems, with additionally in situ formation of the latter system, from azetidine substrates. Chapter 1 discusses the growing importance of azetidines, and the current methods available for making substituted azetidines by ring formation. Further discussion comprises of current sp3 C–H activation approaches α- to nitrogen in heterocyclic compounds as potential methods for sp3 C–H activation on azetidines to give substituted azetidines. Previous work by the Hodgson group in this area is detailed. Chapter 2 describes the advance made towards 2,3-disubstituted azetidines using the thiopivaloyl protecting/activating group, where the latter plays a key role. Optimisation, scope, selectivity and mechanistic insight into the α-deprotonation–electrophile trapping of a 3-hydroxy azetidine system is discussed, which successfully gives access to a range of 3-hydroxy-2-substituted azetidines. Preliminary investigations with 3-alkyl-2-substituted azetidines are also described. Chapter 3 describes the development of a straightforward protocol to make 2-substituted-2- azetines, a rarely studied and difficult to access 4-membered azacycle subclass, from readily accessible azetidine starting materials using α-deprotonation–in situ elimination followed by further α-lithiation–electrophile trapping. Extension of this methodology by transmetallation from the intermediate organolithium to the organocuprate, resulting in greater electrophile scope, is also described.
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Shimamoto, Yasuhiro. "Exploration of New Reactivities of Azetidinols and Alkynylborates." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188616.
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Lenagh-Snow, Gabriel Matthew Jack. "The synthesis of azetidine and piperidine iminosugars from monosaccharides." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:207235d5-2ea5-4724-92fd-924fa0ccd4ed.
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Iminosugars are polyhydroxylated alkaloids, and can be generally defined as sugar mimetics in which the endocyclic oxygen atom has been replaced with a basic nitrogen. A common affect of this atomic substitution is to bestow these compounds with the ability to inhibit various sugarprocessing enzymes; most significantly the glycosidases (glycoside hydrolases) which areintimately involved in a huge array of biological functions. Compounds which inhibit these enzymes concordantly possess much potential as medicinal agents for the treatment of a variety of diseases. Several iminosugars have already achieved market approval as drugs, and many more are promising candidates in the late stages of clinical development. As such there remains considerable interest in this class of compound, both in terms of the exploration of novel iminosugar structures, as well as the continual development of more efficient general methodology for their synthesis. The densely-packed functionality and stereochemical information present in iminosugars makes them challenging targets for asymmetric chemical synthesis, whereas carbohydrates are clearly very attractive as chiral-pool starting materials for this purpose. Indeed, the majority of the most successful syntheses of iminosugars use the latter approach, and such is the focus of this thesis. Chapter 1 presents a relatively brief introduction to iminosugars, including their types of structure, natural occurrence and biological mode of action. The rationale behind their use as therapeutic agents for the treatment of some significant disease targets is also discussed. Chapter 2 is concerned with the preparation of a number of novel polyhydroxylated azetidines, and their evaluation as glycosidase inhibitors. Such compounds represent an almost entirely neglected class of iminosugars within the literature. An overview of natural and synthetic products incorporating an azetidine motif is given, as well as a brief review of preparative methods and known azetidine iminosugars. A highly efficient and flexible method for the key azetidine ring formation is demonstrated by the cyclisations of 3,5-di-O-triflates of pentoses and hexoses, and of a 2,4-di-O-triflate of glucose, with various primary amines. In this manner, many azetidine triols and tetrols were prepared in good yield. Furthermore, this process is readily adaptable to the installation of added functionality to the azetidine scaffold, as demonstrated by the preparation of 1-acetamido analogues. The initial biological screening of these compounds showed a promising array of glycosidase inhibition, including that of selective inhibition of fungal enzymes. Chapter 3 describes a strategy with which to prepare all sixteen stereoisomers of a known piperidine iminosugar, alpha-homonojirimycin (alpha-HNJ), in a highly divergent manner from just four of the possible thirty-two 6-azidoheptitols using traditional chemical synthesis in tandem with biotechnological transformations. One half of the execution of this strategy is described in this thesis. Two 6-azidoheptitols were prepared from D-mannose, thereby providing access to four 6-azidoketoheptoses through a combination of microbial oxidation and enzymatic epimerisation. Catalytic hydrogenation of these 6-azidoketoheptoses furnished four diastereomeric mixtures of 2,6-iminoheptitols, with varying degrees of stereoselectivity. Purification of these mixtures allowed six 2,6-iminoheptitols to be isolated, two of which have never previously been tested for glycosidase inhibition. Significantly, one of them was found to be a potent and highly selectiveinhibitor of alpha-galactosidases, and may therefore be of interest in the treatment of Fabry disease.
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Khan, Rehana Akhter. "Inheritance of azetidine-2-carboxylic acid resistance in Arabidopsis thaliana." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186585.
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A number of hypotheses link salt tolerance in plants to proline accumulation or transport of proline. To begin to understand the genetic basis of this correlation, fifteen mutants of Arabidopsis thaliana were selected for resistance to the toxic proline analog, azetidine-2-carboxylic acid (ACA). These mutants were characterized by seedling growth and proline content on nutrient agar media in the absence and presence of ACA and NaCl. One of these ACA-resistant mutants, KG3, also showed enhanced tolerance to NaCl and was characterized by a recessive trait, transparent testa. Inheritance studies indicated that ACA resistance in KG3 was due to a single recessive gene mutation, named aca1. Genetic mapping studies were done by crossing KG3 with a morphological marker line W100 to determine the chromosomal location of ACa resistance in relation to known markers. Segregation analysis of 180 single-seed-descent F₃ families showed that aca1 was linked to marker tt3. Marker tt3 is located on chromosome V of Arabidopsis thaliana. Segregation of tt3 and aca1 did not show a 9:3:3:1 ratio, suggesting that aca1 was closely linked to tt3, located 62.1 cM from the end of chromosome V. The transparent testa phenotype of KG3 was complemented by locus tt4 also located on this chromosome. To determine the basis of enhanced NaCl tolerance in KG3, F₃ families from a cross between KG3 and Columbia pubescent wild type were tested for NaCl resistance. Families showing optimal growth after release from salt stress were scored for NaCl tolerance. Segregation analysis indicated that the salt tolerance in KG3 was due to a single recessive gene mutation called salt addicted (sad1). The sad1 phenotype appeared to have required NaCl for optimal growth. Segregation analysis of aca1 and sad1 phenotype showed that they were not linked. Molecular mapping of aca-1 was done by using a number of RFLP markers selected from all five Arabidopsis thaliana chromosomes. This study indicated that aca1 was linked with markers m331 and m435, located at positions 73.4 cM and 80.2 cM, respectively, on chromosome V on the unified map of Arabidopsis thaliana. Thus, the map location of aca1 was found to lie within 62 to 67 centimorgans on chromosome V.
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Webster, P. S. "The ease of carbon-nitrogen bond fission in axetidine derivatives." Thesis, University of Huddersfield, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384650.
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ADONIAS, MIREILLE. "Synthese de 2-azetidinones trisubstituees inhibiteurs potentiels d'elastases. Nouvelles voie d'acces radicalaire a des cycles carbapenames et carbapenemes." Paris 11, 1993. http://www.theses.fr/1993PA112324.
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Cette these decrit la synthese enantioselective de beta-lactames utilisant la reaction de staudinger, avec la d-glucosamine comme auxiliaire chiral. Le chapitre i concerne la synthese de monobactames 1,3,4-trisubstitues dont l'etape cle est une reaction de cycloaddition 2+2 entre un cetene et une imine. Le cetene genere a partir de l'acide methoxy acetique ou de l'acide hexanoique, reagit avec une base de schiff chirale obtenue par condensation entre le 3,4;5,6-di-o-isopropylidene 1-propane dithioacetal d-glucosamine et le cinnamaldehyde, ou le methyl-cinnamaldehyde. Les beta-lactames monocycliques ainsi prepares inhibent l'elastase leucocytaire humaine. L'activite inhibitrice ainsi que les relations structure/activite de ces composes ont ete rationalisees par modelisation moleculaire. Dans la premiere partie du second chapitre, sont presentees les syntheses de carbapenames 1,2,3,6-tetrasubstitues obtenus en une seule etape a partir de monobactames prepares avec le 3,4;5,6 di-o-isopropylidene 1-diethyldithioacetal-d-glucosamine comme auxiliaire chiral. La formation du second cycle par une reaction de cylisation radicalaire intramoleculaire est effectuee avec des rendements eleves: la configuration relative des carbapenames a ete deduite selon des donnees #1h rmn et des donnees cristallographiques. Le 1-furanyl carbapename cristallin a ete prepare par utilisation du furylacroleine dans la reaction de staudinger. Dans la seconde partie du chapitre, nous decrivons nos tentatives pour la synthetise d'un 1-benzyl-3-formyl carbapeneme a partir d'un monobactame tetrol. Le tetrol a ete protege selectivement sous forme de 5,6 isopropylidene acetal, suivi de l'oxydation du diol libre en 3,4. L'utilisation du 3,4;5,6 di-o-isopropylidene 1-diethyldithioacetal d-glucosamine comme auxiliaire chiral apparait donc dans le second chapitre comme parfaitement adequate
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Cararas, Shaine A. "Synthesis and Biological Evaluation of Novel GBR 12909 Tropane and Azetidine Hybrid Analogues." ScholarWorks@UNO, 2007. http://scholarworks.uno.edu/td/565.
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The high affinity, selective dopamine transporter ligand GBR 12909 has served as a template for the design of two novel classes of dopamine transporter ligands. A series of 3-[2- (diarylmethoxyethyidenyl)]-N-substituted tropane derivatives were synthesized and the binding affinities of these compounds were determined at the dopamine (DAT), serotonin (SERT) and norepinephrine (NET) transporters in rat brain tissue preparations. The tropane derivatives were found to exhibit more potent affinity and selectivity for DAT than GBR 12909. From the SAR of the tropane analogues and GBR 12909, a novel series of 3-[2-(diarylmethoxyethylidenyl)]-Nsubstituted azetidine derivatives has been developed.
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O'Gorman, P. A. "Some aspects of the chemistry of small ring organic molecules : 1-azetines, 1-azetidinones, 3-oxo-β-sultams and cyclopropenones." Thesis, University of Huddersfield, 2009. http://eprints.hud.ac.uk/id/eprint/6310/.
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The -lactams and the related -sultams are attractive targets for synthesis because of their central importance in antibiotics such as the penicillins. These heterocycles are of further interest because of their potential as inhibitors of the serine protease class of enzymes113, believed to be responsible for diseases such as rheumatoid arthritis and cystic fibrosis. This thesis will describe the synthesis of the 4-vinyl beta lactams (A)25, thiation of these compounds using Lawesson’s reagent to yield thio lactams (B) and subsequent conversion into the corresponding 1-azetine (C) using Meerwein’s reagent. Compound (C) provided a template for a series of cycloaddition reactions in order to produce a series of bicyclic heterocycles, represented by general structure (D). One reaction that was explored in this series was that between 1-azetines (C) and diphenylcyclopropenone (DPP) (E) which should have yielded the bicyclic adducts F). 93 In the event the products isolated were not the anticipated cycloadducts (F) but rather the ring expanded compounds (G)114 obtained via sigmatropic rearrangement, the nucleus of which is an isomer of the azabicyclononane system, present in many important72 alkaloids such as anatoxin-a (H) and pinnamine (I). The project subsequently evolved to look at the possibility of synthesising other alkaloid nuclei such as the pyrrolizidines, indolizidines and pyrroloazepines through the reaction of the appropriate imines with cyclopropenones. These bicyclic systems are present in many natural products72 such as pyrrolam A (J) and indolizidine 223AB (K) and are of great interest for synthesis because of the wide range of biological activities they possess, such as the ability to block the nicotinic receptor channels. This thesis will therefore describe an effective synthesis of the heterocycles shown in Scheme A (where n = 1, 2 or 3). Further research into the reactions of 4-vinyl -lactams (A) has also been conducted with a view to synthesising analogues of the pyrrolobenzodiazepine, antitumour, antibiotic natural products, of which DC-81 (L) is an example.115 Thus, reaction of (A) with o-azidobenzoylchloride gave the N-substituted -lactam (M). Ring closure via an azide-alkene cycloaddition and loss of nitrogen gave either the aziridine compound (N) or the methyl imine (O). Overall the work described in this thesis pioneers initial research into the reactions of electron rich imines with cyclopropenones, positively demonstrating their use in the synthesis of analogues of alkaloid natural products.
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Silva, Junior Jose Antunes da. "Estudo da reatividade de 1-azirinas-3-funcionalizadas frente a difenilceteno-sintese de novas 2-pirrolonas e 2-azetidinonas derivadas." [s.n.], 1996. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250599.
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Orientador: Albert James KascheresTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Doutorado
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Kim, Zin Sig [Verfasser], and Dieter [Akademischer Betreuer] Enders. "Asymmetrische Synthese von 1,3-Aminoalkoholen und deren Anwendung zur Synthese von Azetidinen und 1-Azabicyclen / Zin Sig Kim ; Betreuer: Dieter Enders." Aachen : Universitätsbibliothek der RWTH Aachen, 2007. http://d-nb.info/1137488824/34.
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Nobre, Cintia Maria Rubo de Souza. "Adição de IN3 a derivados de acidos -alquil cinamicos : obtenç2o de 2-alquil-3-fenil-1-azirinas e 3-azido-2-azetidinonas." [s.n.], 1987. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250489.
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Orientador : Albert James KascheresDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Forsyth, Andrea N. "Synthesis and Biological Evaluation of Rigid Analogues of Methamphetamines." ScholarWorks@UNO, 2012. http://scholarworks.uno.edu/td/1436.
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A series of rigid azetidenyl-based methamphetamine analogs were synthesized from commercially available N-Boc-azetidinone. The benzylideneazetidine analogs were prepared via a Wittig olefination via the ylides generated from the corresponding triphenylphosphonium benzylhalide salts. The substituted benzylazetidine analogs were synthesized from the corresponding benzylideneazetidienes via hydrogention over palladium and platinum catalysts. The benzylideneazetidine and benzyliazetidine analogs were evaluated at monoamine transporters as a part of preliminary structure-activity study for the development of novel monoamine transporter ligands. The binding affinities of the azetidine analogs were determined at dopamine (DAT) and serotonin (SERT) transporters in rat brain tissue preparations. The preliminary in vitro binding studies revealed that the rigid scaffold of the azetidine ring system was an effective substitution for the 2-aminopropyl group of methamphetamine and led to compounds with nanomolar binding affinity at dopamine and serotonin. In general, the benzylideneazetidine analogs were more potent than the corresponding benzylazetidine analogs. In addition, the azetidine analogs were more selective for the serotonin transporter than the dopamine transporter. The 3-(3,4-dichlorobenzylidene)azetidine (24m) was the most potent analog of the series with Ki values of 139 nM for SERT and 531 nM for DAT (DAT/SERT = 3.8).
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Dupas, Alexandre. "Ouverture de composés 1-azabicycliques : synthèse d'azépanes et d'azétidines." Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLET026.
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Les hétérocycles azotés sont rencontrés dans de très nombreux produits naturels et/ou biologiquement actifs. Le développement de méthodes de synthèse sélectives d’hétérocycles azotés constitue donc un défi important pour la découverte de nouvelles molécules actives en chimie médicinale ou en agrochimie. Dans ce contexte, nos travaux ont porté sur la mise au point de réactions d’ouverture régiosélectives de composés 1-azabicycliques, diversement substitués, par des nucléophiles pour accéder à des azépanes et à des azétidines. Des 1 azabicyclo[4.1.0]heptanes ont été préparés à partir d’azirines, par une séquence impliquant une allylation diastéréosélective et une métathèse cyclisante pour construire le cycle à six chaînons, puis la transformation de la double liaison carbone-carbone endocyclique grâce à des réactions d’hydrogénation, d’addition-1,4 ou de cycloaddition 1,3-dipolaire. Différentes conditions ont été développées pour réaliser ensuite l’ouverture régiosélective des 1 azabicyclo[4.1.0]heptan-2-ones ainsi obtenues par des acides carboxyliques, des thiols ou des thioacides, ce qui a permis d’accéder à des azépanones diversement substituées, possédant une fonction ester ou un groupe trifluorométhyle en alpha de l’atome d’azote. La cyclopropanation diastéréosélective de 2-(trifluorométhyl)azirines a été utilisée pour construire de nouveaux 1 azabicyclo[1.1.0]butanes dont l’ouverture régiosélective par des chloroformiates et par l’anhydride trifloroacétique a ensuite conduit respectivement à des 3 chloroazétidines ou des azétidin-3 ols trifluorométhylés possédant deux centres stéréogènes adjacents contrôlésNitrogen heterocycles are encountered in numerous natural products and/or bioactive compounds. The development of selective synthetic methods toward nitrogen heterocycles is of prime importance for the discovery of new bioactive compounds in medicinal chemistry of agrochemistry. In this context, our research work has been devoted to the design of regioselective ring-opening reactions of diversely substituted 1-azabicyclic compounds, with the goal of accessing azepanes and azetidines. Several 1-azabicyclo[4.1.0]heptanes were prepared from azirines, through a sequence involving a diastereoslective allylation and a ring-clsoing metathesis reaction to construct the six-membered ring, followed by transformation of the endocyclic olefin using either a hydrogenation, a 1,4-addition or a 1,3-dipolar cycloaddition. Then, different conditions were developed to achieve the ring-opening of the resulting 1 azabicyclo[4.1.0]heptan-2-ones, using carboxylic acids, thiols and thioacids as nucleophiles, which eventually delivered diversely substituted azepanones possessing an ester moiety or a trifluoromethyl group at the alpha position of the nitrogen atom. The diastereoselective cyclopropanation of 2 (trifluoromethyl)azirines was used to elaborate new substituted 1 azabicyclo[1.1.0]butanes, which then underwent regioselective ring-opening with chloroformates and trifluoroacetic anhydride to provide trifluoromethylated 3 chloroazetidines or azetidin-3 ols incorporating two adjacent stereocenters
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Mortimer, Claire. "New transformations of azacycles." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:1fe27dc8-6525-4d45-a398-b3e6531e7b99.
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The work presented in this thesis involves new transformations of azacycles, focusing on the introduction of functionality α-to N. α-C-H functionalisation on an azetidine has been a long-standing challenge, with N-protecting/activating groups that work well in the higher and lower azacyclic systems not viable. A recent breakthrough in the Hodgson group showed the rarely used N-thiopivaloyl group was effective for α-deprotonationâ electrophile trapping on azetidines, but was not without limitations concerning harsh removal conditions and scope for further substitutions. This thesis describes efforts to overcome these issues by development of a new protecting/activating group for N, t-butoxythiocarbonyl (Botc).
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Calet, Serge. "Chimie organometallique d'heterocycles a trois chainons (carbonylation, desulfuration, couplage)." Paris 6, 1987. http://www.theses.fr/1987PA066292.
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Honcharenko, Dmytro. "Conformationally Constrained Nucleosides, Nucleotides and Oligonucleotides : Design, Synthesis and Properties." Doctoral thesis, Uppsala universitet, Bioorganisk kemi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8887.
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This thesis is based on six original research publications describing synthesis, structure and physicochemical and biochemical analysis of chemically modified oligonucleotides (ONs) in terms of their potential diagnostic and therapeutic applications. Synthesis of two types of bicyclic conformationally constrained nucleosides, North-East locked 1',2'-azetidine and North locked 2',4'-aza-ENA, is described. Study of the molecular structures and dynamics of bicyclic nucleosides showed that depending upon the type of fused system they fall into two distinct categories with their respective internal dynamics and type of sugar conformation. The physicochemical properties of the nucleobases in the conformationally constrained nucleosides found to be depended on the site and ring-size of the fused system. The incorporation of azetidine modified nucleotide units into 15mer ONs lowered the affinity toward the complementary RNA. However, they performed better than previously reported isosequential 1',2'-oxetane modified analogues. Whereas aza-ENA-T modification incorporated into ONs significantly enhanced affinity to the complementary RNA. To evaluate the antisense potential of azetidine-T and aza-ENA-T modified ONs, they were subjected to RNase H promoted cleavage as well as tested towards nucleolytic degradation. Kinetic experiments showed that modified ONs recruit RNase H, however with lower enzyme efficiency due to decreased enzyme-substrate binding affinity, but with enhanced turnover number. Both, azetidine-T and aza-ENA-T modified ONs demonstrated improved 3'-exonuclease stability in the presence of snake venom phosphodiesterase and human serum compared to the unmodified sequence. Oligodeoxynucleotides (ODNs) containing pyrene-functionalized azetidine-T (Aze-pyr X) and aza-ENA-T (Aza-ENA-pyr Y) modifications showed different fluorescence properties. The X modified ODNs hybridized to the complementary DNA and RNA showed variable increase in the fluorescence intensity depending upon the nearest-neighbor at the 3'-end to X modification (dA > dG > dT > dC) with high fluorescence quantum yield. However, the Y modified ODNs showed a sensible enhancement of the fluorescence intensity only with complementary DNA. Also, the X modified ODN showed decrease (~37-fold) in the fluorescence intensity upon duplex formation with RNA containing a G nucleobase mismatch opposite to the modification site, whereas a ~3-fold increase was observed for the Y modified probe.
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Glawar, Andreas Felix Gregor. "Design, synthesis and biological evaluation of glycosidase inhibitors in an anti-cancer setting." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:602edf26-d9ff-4fcf-8dec-c8548f3578da.
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The aim of the work described in this thesis was to explore the synthesis of glycosidase inhibitors and to evaluate their potential as anti-cancer agents. Glycosidases catalyze the fission of glycosidic bonds and are involved in vital biological functions. With regard to their potential for anti-cancer therapy, two glycosidases were identified: α-N-acetyl-galactosaminidase and β-N-acetyl-hexosaminidase. The former has been implicated in causing immunosuppression in advanced cancer patients by negating the effect of the macrophage activating factor (MAF), while the latter is secreted by invading cancer cells and hence associated with metastasis formation. The synthetic focus was on generating piperidine and azetidine iminosugars, carbohydrate mimetics with their endocylic oxygen replaced by nitrogen. Their structural similarity to carbohydrates make iminosugars excellent inhibitors of glycosidases. Following synthesis of a pipecolic amide, its previously reported potent β-N-acetyl-hexosaminidase inhibition was confirmed. This data, along with inhibition profiles of several pyrrolidines, allowed the generation of a molecular model for predicting activity of β-N-acetyl-hexosaminidase inhibitors. The model was used to select azetidines in the D/L-ribo and D-lyxo configuration as suitable candidates to be explored in novel chemical space, leading to the first synthesis of a fully unprotected 3-hydroxy-2-carboxy-azetidine. The potent α-N-acetyl-galactosamindase inhibitor 2-acetamido-1,2-dideoxy-D-galacto-nojirimycin (DGJNAc) was successfully derivatised via N-alkylation. Important structural discoveries with regard to glycosylation of vitamin D3-binding protein, the precursor of MAF, were made using MALDI mass-spectrometry. By comparing the enzymatic and cellular inhibition of N-alkylated derivatives of DGJNAc and a pyrrolidine the following generalization on iminosugar biodistribution was found: N-butylation promotes uptake into the cell/organelles, while hydrophilic side-chains restrict cellular access. An in vitro assay evaluating cancer cell invasion was devised and β-N-acetyl-hexoamindase inhibitors were shown to retard cell migration, including with the highly metastatic breast cancer cell line MDA-MB-231. Additive effects where found when the iminosugar was combined with a protease inhibitor, suggesting potential for future combination therapy.
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Varghese, Oommen P. "Conformationally Constrained Nucleosides : Design, Synthesis, and Biochemical Evaluation of Modified Antisense Oligonucleotides." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8266.
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Pertschi, Romain. "Elaboration d'hétérocycles complexes par ammoniumation catalysée à l'or(I)." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAF036.
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Les hétérocycles azotés ont toujours retenu l’attention des chimistes du fait de leurs potentielles activités biologiques mais également pour leurs grandes occurrences dans les produits naturels. De ce fait émerge la nécessité de développer de nouvelles méthodes de synthèse innovantes permettant un accès rapide et efficace à ces hétérocycles. C’est dans cette philosophie que s’inscrivent ces travaux de thèse dont l’objectif est le développement de nouvelles approches basées sur l’utilisation de réactions d’ammoniumation catalysées à l’or(I) afin d’induire des cascades réactionnelles donnant accès à une large variété d’hétérocycles azotés. Ainsi, un motif de base N-sulfonyl-2-(1-propargyl)azétidine a permis d’accéder à une large variété de dérivés pyrroliques et de tétrahydroazépines. L’extension du concept d’ammoniumation lors de l’utilisation des N-(2-alcynylaryl)sulfonyl azétidines a conduit à l’obtention de benzosultames. Un autre défi majeur de la chimie de synthèse moderne est l’obtention de molécules énantiopures. Pour répondre à cette problématique, de nouveaux complexes chiraux NHC platine(II) ont été synthétisés et évalués en tant que catalyseurs sur des réactions de cycloisomérisationNitrogen-containing heterocycles have always retained the attention of chemists considering their potent biological properties as well as their large occurrence in natural product structures. Therefore, the development of new innovative synthetic methods that allow a rapid and efficient access to these heterocycles is highly sought. It is in this philosophy that these PhD works take place, whose aims at the development of new approaches based on gold(I) catalyzed ammoniumation reactions in order to trigger cascade reactions and to reach important nitrogen-containing heterocycles. The N-sulfonyl-2-(1-propargyl) azetidine scaffold allows formation of a large variety of pyrroles and tetrahydroazepines derivatives. The extension of the concept of ammoniumation by using N-(2-alcynylaryl)sulfonyl azetidines allowed the formation of benzosultam derivatives. Another major challenge of modern synthetic chemistry is the formation of enantiopur molecules. To reach this goal, new chiral NHC platinum (II) complexes have been synthesized and evaluated as catalysts for cycloisomerization reactions
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Martinand-Lurin, Élodie. "Hétérocycles et réactions pallado-catalysées : développements méthodologiques, études mécanistiques et application en synthèse totale." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112018/document.
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Le développement de nouvelles méthodologies de synthèse toujours plus efficaces, sélectives et éco-compatibles apparaît comme un défi permanent tant l’intérêt suscité pour les composés hétérocycliques est important. Ce projet de thèse s’articule autour de plusieurs axes dans ce domaine.Tout d’abord, nous avons exploité la réactivité des N-(sulfonyl) et N-(sulfamoyl)aziridines en tant que précurseurs de dipôles 1,3 en vue de préparer divers 1-azaspiro[5.n]alcanes. L’étude mécanistique de cette réaction de cycloaddition [3+2] réalisée par calculs DFT permet de montrer que l’étape cinétiquement déterminante de la réaction est la formation du dipôle 1,3 ; la force motrice étant la fermeture du cycle à cinq chaînons.Nous nous sommes également attachés à valoriser le savoir-faire du laboratoire dans le domaine des transferts catalytiques de nitrènes (aziridination et amination C-H) dans le cadre du projet de synthèse totale de la pactamycine, aminocyclopentitol hautement fonctionnalisé.Par ailleurs, la mise au point d’une cascade Passerini-Smiles/Réduction/Cyclisation et d’une séquence monotope Passerini-Double-Smiles/SNAr permet un accès rapide et efficace à des motifs hétérocycliques de type 1,4-benzoxazin-3-ones. Conduisant à des familles régioisomères de produits, ces deux voies de synthèse se sont avérées complémentaires.Parallèlement, une nouvelle méthodologie basée sur l’ouverture pallado-catalysée de thiocyclopropanes a permis d’obtenir de nouveaux hétérocycles de type thiochromènes. Compte tenu des nombreuses fonctionnalisations envisageables, ces composés semblent très prometteurs dans le domaine de la chimie hétérocyclique.Enfin, des études électrochimiques et RMN couplées à des calculs DFT ont été entreprises afin d’élucider le mécanisme mis en jeu lors des couplages pallado-catalysés entre un halogénure d’aryle, un isonitrile et un nucléophileThe development of new and more efficient synthetic methodologies, selective and eco-friendly seems to be an ongoing challenge as the interest in the heterocyclic compounds is important. All the studies performed during the last three years are divided in several axes in this field.First, the reactivity of N-(sulfonyl) and N-(sulfamoyl) aziridines as precursors of 1,3-zwitterionic species was explorated in order to obtain various 1-azaspiro[5.n]alkanes. The mechanism of the reaction has been studied by DFT calculations. The initial formation of the zwitterionic 1,3-dipole has been found to be the rate-determining step whereas the five-membered ring closure appeared to be the driving force.We tried to apply our expertise in the field of catalytic nitrene transfers (aziridination and C-H amination) to the total synthesis of pactamycin, highly functionalized aminocyclopentitol compound.Furthermore, the developments of a Passerini-Smiles/reduction/cyclization cascade and of a one-pot Passerini-Double-Smiles/SNAr sequence provide straightforward and efficient accesses to 1,4-benzoxazin-3-ones. These paths are complementary as they lead to regioisomers.Meanwhile, a new methodology based on Pd-catalyzed thiocyclopropanes ring opening gave thiochromenes. Due to their high synthetic potential, these compounds appear to be very promising scaffolds in heterocyclic chemistry.Finally, electrochemical and NMR studies coupled with DFT calculations have been done in order to elucidate the mechanism involved in the Pd-catalyzed couplings between an aryl halide, an isocyanide and a nucleophile
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"3-azetidinonas e 3-azetidinois : preparação e aplicações na sintese de azetidinas substituidas." Tese, Biblioteca Digital da Unicamp, 2006. http://libdigi.unicamp.br/document/?code=vtls000377636.
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Sajjadi, Hashemi Zohreh. "Substituted azetidine-2 carboxylic acid synthesis." Thèse, 2006. http://hdl.handle.net/1866/16791.
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Wang, Shih-Chieh, and 王世杰. "The Azetidine Chemistry for Aqueous-based Polyurethane and Other Applications." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/22425065775437069592.
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博士淡江大學
化學學系博士班
95
In this research, the modification of aqueous-based polyurethane (PU) dispersion is the main target. Because the traditional aqueous-based PU resin is linear polymer and because it has low average molecular weight which causes the traditional aqueous-based PU exhibits poor organic solvent resistant and low mechanical performance. In this research, a series of azetidinyl-containing curing agent, triaziridinyl-containing curing agent, mono-aziridinyl and mono-isocyanate containing curing agent and tri-oxirane-containing curing agent are synthesized and introduced into aqueous-based PU dispersion to act as the latent curing agent at ambient temperature. The chemical structures of these synthesized curing agents are identified by FT-IR and FT-NMR. The curing reaction between curing agent and PU is explained by the modeling reaction. The physical properties (such as gel content, water-uptake, degree of alcohol swollen, contact angle, hardness etc.), the tensile strength, the thermal properties of these cured PU resins are evaluated in this research.
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LEE, KANG MAN. "BIOSYNTHESIS OF L-AZETIDINE-2-CARBOXYLIC ACID IN ACTINOPLANES FERRUGINEUS." 1985. http://catalog.hathitrust.org/api/volumes/oclc/68296740.html.
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YEUNG, KING-FAI. "DEGRADATION OF L-AZETIDINE-2-CARBOXYLIC ACID BY ENTEROBACTER AGGLOMERANS AND E. AMNIGENUS." 1987. http://books.google.com/books?id=8URtAAAAMAAJ.
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Hsin-Yi, Wei, and 魏欣怡. "Study on Nylon 6 Synthesis via Anionic Polymerization Using Azetidine-2,4-diones as the Activators." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/77557112602501694593.
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碩士國立中興大學
化學工程學系
93
This research focused on the study of anionic ring-opening polymerization of caprolactum to synthesize Nylon 6 using structurally varied azetidine-2, 4-diones as the activators. The polymerizations were carried out by a one-step melt-process to find out the effects of activator’s concentration, types (aromatic or aliphatic), functionalities ( n=1 and 2), substituents (on azetidine-2,4-dione ring) as well as those of reaction temperature on polymerization rates. The aim is to find the best activator and optimal condition for possible application in reaction injection polymerization of Nylon 6 (Nylon RIM). In the aromatic series, different aliphatic substituent groups at 3,3’-prosition of azetidine-2,4-dione rings showed great effects on conversion rate and time of Nylon 6’s crystallization. It was found that aromatic bisazetidine-2,4-diones based on MDI with 3,3’-diethyl- or 3-ethyl-3’-butyl-groups exhibited the best overall performances which were twice as fast than that of N,N’-isophthaloyl-bis-caprolactam in getting high molecular weight Nylon 6 (molecular wt. of ~70,000) in about 70 seconds at 140℃. Unexpectedly, substitution of less-hindered di-methyl groups at 3, 3’-positions of the ring resulted in a slower polymerization and crystallization of Nylon 6. Complications of cross-linking and branching in the polymerization seemed responsible for this abnormality. Further study on Nylon-6 polymerizations were also conducted with bis-azetidine-2, 4-diones possessing long-chained polyether groups derived from Jeffamine D4000 Polymerization of Nylon-6 on the azetidine-2,4-dione prepolymers resulted in the formation of triblock-type systems. As might be expected in these cases, the polymerization rate of caprolactum was inversely proportional to the content of polyether groups in the prepolyemrs due to dilution. The triblock polymer prepared exhibited a well-organized phase-segregation in its morphology.
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Gries, Jörg [Verfasser]. "1,3-Aminoalkohole als Bausteine in der asymmetrischen Synthese von Azetidinen, Azetidincarbonsäuren und Piperidin-3-olen / vorgelegt von Jörg Gries." 2005. http://d-nb.info/977243362/34.
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Cheng, Hsin-Yu, and 張新佑. "Rapid Melt Synthesis of Elastomers from Bis-azetidine-2,4-dione Intermediates and Study of their Structure and Morphology Relationships." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/12161778229001993677.
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碩士國立中興大學
化學工程學系所
94
Two methods of synthesizing bis-azetidiene-2, 4-dione intermediates have been accomplished in our lab for preparation of three bis-azetidine-2, 4-dione, PBAZ, MBAZ, and LBAZ for our study. Using a thermal process, diethylketene cyclo-adds to aromatic diisocyanates to form aromatic bis-azetidine-2, 4-diones. The yields of bis-aztidine-2, 4-diones from p-phenylene diisocyanate(PPDI) and 4, 4’-dipehnylene diisocyanate (4, 4’-MDI) were found to be 74％ (for PBAZ) and 82% (MBAZ) respectively. Whereas, N, N’-hexamethylene bis-azetidine-2, 4-dione(LBAZ) an aliphatic counterpart, was prepared differently by photolysis of hexamethylene-bis-N-formyl-N-methacrylamides in 71%. Melt-polymerization of bis-azetidine-2, 4-diones with hexamethylene diamine yielded polymalonamides. Similar melt-polymerization has also been extended to synthesize polymolonamide elastomers using Jeffamine® D2000 as the soft-segment component and hexamethylene diamine as the extender with each of the prepared bis-azetidine-2, 4-diones. Elastomers of 35%, 45% and 55% hard-segment contents in each series were prepared. All syntheses were carried out by a two-step process by formation of pre-polymers between individual azetidine-2, 4-diones with Jeffamine* in the first step. The second step to the final product was done with hexamethylene diamine as the extender. Very rapid conversions to the final products were observed universally in less than 150 sec. The polymalonamide elastomers prepared were analyzed by TGA, DSC, DMA, AFM and FE-SEM to characterize morphology of the products. All elastomers prepared from PBAZ and LBAZ are semi-crystalline in nature. Especially, three PBAZ derived elastomers crystallize readily to form distinctive oval island-shape domains as observed by AFM, and are characterized by their sharp Tg,s and Tg,h in DSC and DMA. The domain sizes are uniformly distributed between 200nm to 300nm with increasing larger sizes for higher hard-segment contents. Although semi-crystalline LBAZ-derived elastomers also showed similar phase-segregation in AFM, but their patterns were different and could be influenced greatly by processing techniques. Under high spinning rates of greater than 4000 rpm in spin-coating process, the morphology of LBAZ-elastomers turned into fibrous pattern. Our study indicated that only MBAZ-elastomers are amorphous and showed well mixing between hard and soft segments as indicated by the appearances of Tg,s and new Tg,m at -10~18℃ for the mixed phases in DSC. The physical properties of elastomers have been found to be greatly influenced by morphology and by the hard-segment contents but appeared to be in lesser degrees for the latters.
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Hsu, Chih-Hsiung, and 許智雄. "Determination of critical micelle concentration of dendritic surfactant synthesized via a selective ring-opening addition reaction of azetidine-2,4-dione." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/48291832529694579404.
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碩士中興大學
化學工程學系所
99
In this study, a series of dendrons with four carbons were synthesized and extended to obtain a dendritic surfactant. An azetidine-2,4-dione has been applied to synthesize dendrons on account of the characteristic of ring-opening reactions. The characteristics of [G-1]-C4 dendron were examined by fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (1H NMR), elemental analyzsis (EA) and fast atom bombardment mass spectrometry (FAB MS) analyses. The dendritic surfactant was obtained from [G-1]-C4 dendron and dissolved in 2 wt % dimethyl sulfoxide (DMSO) water-DMSO solution to observe the critical micelle concentration (CMC). This dendritic surfactant was ionic with hydrophilic and hydrophobic groups. The CMC was determined by electrical conductivity and fluorescence measurements. From this result, the CMC was very close within measurements. Moreover, transmission electron microscopy (TEM) could confirm the formation and shape of micelle. Zeta potential measurement also provided an evidence of forming micelles. To extend the application, it adsorbed anion dyes successfully by its cation head group.
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Lee, Jiyeon. "Analysis of the enzymological properties of prolyl-tRNA synthetases in plants focusing on the misactivation of the proline analog azetidine-2-carboxylic acid." 2009. http://hdl.rutgers.edu/1782.2/rucore10001600001.ETD.000052259.
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Sung, Wei-Wen, and 宋維文. "Part I : Immunolocalization of Oryza sativa ClassⅠLow Molecular Mass Heat Shock Protein Expressed in E. coli in Relation to Thermotolerance Part II : Immunolocalization of Azetidine Induced Class I Low-Molecular- Mass Heat Shock Proteins in Soybean." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/77152902829913943363.
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碩士國立臺灣大學
植物學研究所
89
Escherichia coli cells were transformed with pUC8 (pUC8 vector only), pUC-FL (rice class I low molecular mass heat shock protein Oshsp16.9 cDNA ORF inserted into pUC8), and pUC-C108 plasmids (DNA fragment containing C-terminal 108 amino acids of Oshsp16.9 cDNA ORF inserted into pUC8) previously in our laboratory and the recombinant proteins were expressed. In the present study, the ultrastructural changes of the transformed E. coli cells affected by heat shock were studied with electron microscopy. Meanwhile, immunolocalization and the movement of Oshsp16.9 or its fragment in E. coli cells affected by heat shock were also reported. Escherichia coli grown under normal environment, cells was enclosed by cell wall with dense ectoplasm and more or less light endoplasm, in which nucleoid region located. With IPTG induction or heat treatment, some dark regions were found in ectoplasm. Having been transferred back to 37℃ after heat shock, about 27% of pUC-FL cells pretreated with IPTG induction recovered to normal. Cells without IPTG pretreatment, only had 0~8% of recovery. These results are in agreement with the thermoprotection of Oshsp16.9. Immunolocalization of Oshsp16.9 expressed in E. coli after IPTG induction were found both in pUC-FL and pUC-C108 transformed clones. Quantitative comparison of immuno-gold particles in cells under different treatments showed results as follows: there was a distinct difference in Oshsp16.9 expression of cells with and without IPTG induction; there was no conspicuous movement of Oshsp16.9 in normal or high temperature environment; and the density of gold particles in dark regions was higher than that in other regions. In the second part of this thesis, class I low molecular mass heat shock protein induced by azetidine were precipitated with mitochondria by subcellular fraction were investigated. In this issue, immunolocalization of soybean class I low molecular mass heat shock protein induced by azetidine were performed. Most of the class I low molecular mass heat shock protein accumulated in the cytoplasm and the less around mitochondria of soybean seedlings pretreated by azetidine. When seedlings pretreated with azetidine were transferred back to normal condition and their heat shock proteins would move to cytosol. When soybean seedlings pretreated with azetidine were shifted to heat shock of 40℃, the class I heat shock proteins were observed more abundant in cytosol.