To see the other types of publications on this topic, follow the link: Michael's Addition.
Dissertations / Theses on the topic 'Michael's Addition'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Michael's Addition.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Clement, Baptiste. "Nouvelles résines sans isocyanates réactives à basses températures pour revêtements elastomères durables." Thesis, Mulhouse, 2020. http://www.theses.fr/2020MULH4567.
Full textAbstract:
L’objectif de la thèse est d’explorer de nouveaux systèmes chimiques à réactivité élevée à température ambiante et les soumettre à un cahier des charges de polymères thermodurcissables. Ce projet a été construit autour de deux chimies capables de s’effectuer dans des conditions douces : l’addition d’aza-Michael et la cycloaddition de Diels-Alder. L’addition d’aza-Michael est une réaction spontanée à température ambiante, s’effectuant entre une fonction amine et un composé insaturé comme les acrylates. Cette réaction peut être réalisée sans solvants ni catalyseurs. Elle est donc couramment utilisée depuis de nombreuses années dans le domaine des polymères. Une autre voie faisant également l’objet de nombreuses études dans les thermodurcissables est la réaction de cycloaddition de Diels-Alder, s’effectuant entre un diène et un diénophile. L’avantage de cette réaction est son caractère potentiellement réversible, effectif à partir de températures supérieures à 100°C. Les travaux de la thèse ont été divisés en deux chapitres importants dans lesquels l’addition d’aza-Michael a été principalement utilisée. Un premier chapitre a été consacré au développement de nouveaux systèmes mono-composants, et l’autre à l’obtention de systèmes bi-composants. Pour la première partie, différents systèmes mono-composants ont été préparés par addition de Michael. Concernant le deuxième chapitre, une partie a été dédiée à l’utilisation de la cycloaddition de Diels-Alder pour l’obtention de matériaux réticulés. L’autre partie s’est consacrée à l’emploi de l’addition aza-Michael via plusieurs systèmes de réticulationThe aim of the thesis is to explore new chemical systems with high reactivity at room temperature and to submit them to coatings specifications. Two chemicals reactions performing under mild conditions was used : the aza michael additionn and the Diels-Alder cycloaddition. The aza-Michael addition is a spontaneous reaction at room temperature between an amine function and an unsaturated compound such as acrylates. This reaction can be carried out without solvents or catalysts. The other one that has also been the subject of numerous studies in thermosets field is the Diels-Alder cycloaddition reaction, carried out between a diene and a dienophile. The advantage of this reaction is its potentially thermo-reversible nature.The work of the thesis was divided into two important parts in which the aza-Michael addition was mainly used. The first chapter was devoted to the development of one-component systems, and the other one to the production of two-component systems. For the first chapter, several one-component systems have been prepared by Michael addition. Concerning the second chapter, a part was dedicated to the use of the Diels-Alder cycloaddition for obtaining thermosets. The other part is devoted to the use of aza-Michael addition via several crosslinking systems
2
Schultz, Alison. "From Block Copolymers to Crosslinked Networks: Anionic Polymerization Affords Functional Macromolecules for Advanced Technologies." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/81835.
Full textAbstract:
Ion-containing macromolecules continue to stimulate new opportunities for emerging electro-active applications ranging from high performance energy devices to water purification membranes. Progress in polymer synthesis and engineering now permit well-defined, ion-containing macromolecules with tunable morphologies, mechanical performance, ion conductivity, and 3D structure in order to address these globally challenged technologies. Achieving tailored chemical compositions with high degrees of phase separation for optimizing conductivity and water adsorption remains a constant synthetic challenge and presents an exciting opportunity for engineering sophisticated macromolecular architectures. This dissertation will introduce unprecedented charged polymers using conventional free radical and anionic polymerization to incorporate ionic functionalities based on phosphonium cations. This new class of copolymers offers unique properties with ionic functionality for tailorable electro-active performance.Ph. D.
3
Pelzer, Silke. "Wie es geht eine quantenchemische Untersuchung der eisenkatalysierten Michael-Reaktion /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971232482.
Full text
4
Young, Douglas M. "Explorations of Cascading Michael Additions." Thesis, University of Oregon, 2011. http://hdl.handle.net/1794/12069.
Full textAbstract:
xx, 214 p. : ill. (some col.)Intramolecular cascading Michael additions have the ability to transform simple, symmetric substrates into densely functionalized compounds containing new ring structures and chiral centers. The Rauhut-Currier (RC) reaction, also known as the vinylogous Morita-Baylis-Hillman reaction, utilizes this type of reactivity by cyclizing tethered, activated alkenes using phosphine or thiolate catalysis. This dissertation describes the expansion of the scope of the RC reaction, the introduction and importance of co-catalysts to cascading Michael additions, the development of the first amine-catalyzed RC reaction, and the transformation of cyclization products into fused, polycyclic aromatic compounds. Chapter I reviews the development and applications of the Rauhut-Currier reaction. Chapter II describes the regioselective synthesis of di-substituted indenes and introduces phenol as a rate- and selectivity-enhancing co-catalyst. Although tertiary amine nucleophiles were found to be inferior to phosphines as cyclization catalysts, chapter III discusses the ability of unhindered primary and secondary amines to undergo a diastereoselective, cascading aza-Michael-Michael addition to yield a wide variety of amino-indanes in the presence of an acid catalyst. Recognizing the importance of protic environments and small nucleophiles, the development of the first amine-catalyzed intramolecular RC is introduced in chapter IV. Chapter V describes the conversion of methyl ketone-substituted indenes to fluorene derivatives via an intramolecular aldol reaction. Chapter VI describes the serendipitous discovery and synthesis of indenopyrylium salts. Chapter VII details the novel production of indenopyridines from di-substituted indenes. Lastly, chapter VIII provides a summary and suggests future directions for this research. This dissertation includes previously published and unpublished co-authored material.
Committee in charge: Shih-Yuan Liu, Chairperson; Kenneth Doxsee, Advisor; David Tyler, Member; Michael Haley, Member; A. Dana Johnston, Outside Member
5
Santoro, Francesco. "Ruthenium/PNNP-catalyzed asymmetric Michael addition /." Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17024.
Full text
6
Chotsaeng, Nawasit. "Enantioselective rhodium-catalysed addition of allylboron reagents to cyclic imines and enantioselective nickel-catalysed Michael additions of 2-acetylazaarenes to nitroalkenes." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/16192.
Full textAbstract:
Rhodium-catalysed enantioselective allylation reaction of imines in the presence of chiral diene ligands has been investigated. Under the optimised conditions, cyclic imines provided homoallylic amines in high yield and excellent enantioselectivities. The reaction most likely proceeds via allylrhodium(I) intermediates, and represents the first rhodium-catalysed enantioselective nucleophilic allylation of π-electrophiles with allylboron compounds. Furthermore, the allylations display a strong preference for carbon–carbon bond formation at the more substituted terminus of the allyl fragment of the allyltrifluoroborate. To demonstrate the utility of the allylation products, representative manipulations were conducted. Enantioselective Nickel-Catalysed Michael Additions of 2-Acetylazaarenes to Nitroalkenes An enantioselective Michael addition of acylazaarenes with α-substituted β-nitroacrylates in the presence of a chiral Ni(II)–bis(oxazoline) complexes has been developed. A range of azaaryl nucleophiles were shown to react with a variety of nitroalkenes to construct highly functionalised Michael addition products which contain a stereogenic all-carbon quaternary stereocentre with moderate to high yields and enantioselectivities. A possible mechanism for this reaction has been proposed.
7
Sawicki, Marcin. "Synthèse et criblage de ligands puissants de l'uranyle : application à la décorporation de l'uranium." Paris 11, 2005. http://www.theses.fr/2005PA112075.
Full textAbstract:
Ce travail de thèse, réalisé dans le cadre du programme " Toxicologie Nucléaire " du CEA, a été consacré à l'élaboration de ligands puissants de l'ion uranyle (UO22+) pour des applications de décorporation et à des fins analytiques. Suite à la mise au point d'une méthodologie de synthèse en mode parallèle, utilisant la réaction de Michael comme étape clé, une banque d'environ 200 molécules a été obtenue. Cette banque de ligands potentiels, ainsi que plus de 100 molécules obtenues par collaboration, ont été soumises à un test de criblage que nous avons également développé au laboratoire. Plus d'une vingtaine de ligands possédant des constantes de complexation pour l'ion uranyle supérieures à 10 puissance 17 ont ainsi été révélés à l'aide de ce criblage à haut débit. Toutes ces molécules se sont avérées être des structures possédant plusieurs motifs bis-phosphonates. Parmi elles, une seule présente des propriétés de décorporation in vivo. D'autre part, certains ligands bis-phosphoniques forment des complexes avec UO22+ ayant des propriétés de fluorescence remarquables et permettent d'améliorer les méthodes de détection de ce métalThis work was realised as a part of prorgamm "Nuclear Toxicologie" created by CEA and was dedicated to the synthesis of powerfull ligands of uranyl for the applications in decorporation and detection of uranyle. During this work about 200 new potentiales ligands of uranyle was synthesised in the parallele manner using as a key step of the synthesis peptide coupling as well as new parallel synthesis methodology based on the addition of Michael. This library of potencial uranyle ligands, enreached by 100 molecules obtained by collaboration, was submited to high throughput screening test for affinity against uranyle ion using colorimetric agent - sulfochlorophenole S as reference chelate. More then twenty ligands having conditional stability constant against uranyl at pH=7. 4 higher then 10 to 17 were found. All this molecules have methylene biphosphonate unite as chelating function. Beetwen them only one was foun to decorporate uranium in vivo. On the other hand some ligands methylene biphosphoniques were found to forme with uranyle ion the complexes posseding exceptional proprietes of fluorescence what may aloowed for their use for the detection of uranyle
8
Poderi, Cecilia. "Synergistic catalysis: Michael addition of acyl-pyridines." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14409/.
Full textAbstract:
A new diastereo- and enantioselective strategy for the functionalization of 2-acetyl-pyridine with α,β-unsaturated aldehydes has been investigated through synergistic catalysis. In particular, the aim of the work was to use cinnamaldehydes bearing different substituents on the phenyl group and to study its effect on the yield, conversion and stereoselectivity of the reaction. The reaction mechanism involves combined iminium ion and transition metal catalysis in a synergistic fashion and proceeds with two consecutives Michael additions, followed by final intramolecular aldol condensation to yield the formation of three new stereogenic carbons, with high to excellent stereoselectivities. The structures of the molecules obtained were fully characterized by NMR spectroscopy. After having assigned the relative configuration by NOE-NMR and 2D-COSY experiments, conformational analysis was performed by DFT calculations to find the most stable molecular conformations. The absolute configuration of each diastereoisomer was then eventually assigned by quantum mechanical simulations of the Electronic and Vibrational Circular Dichroism spectra.
9
Howard-Jones, Andrew Glyn. "A synthetic approach to Câ†2 symmetric guanidine bases and the synthesis of model compounds of ptilomycalin A." Thesis, Bangor University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340956.
Full text
10
Du, Haiying. "Michael addition-initiated organocatalytic enantioselective multicomponent reactions with 1,3-dicarbonyls." Thesis, Ecole centrale de Marseille, 2014. http://www.theses.fr/2014ECDM0002/document.
Full textAbstract:
Ce mémoire de thèse se concentre sur le développement de réactions multicomposants énantiosélectives de dérivés 1,3-Dicarbonylés en présence d'un organocatalyseur, en vue de préparer des motifs polyhétérocycliques fusionnés.Dans un premier temps, nous décrivons nos résultats initiaux sur une réaction multicomposants énantiosélective avec des énals et des amines primaires simples. Au vu des faibles énantiosélectivités obtenues, des amines fonctionnalisées ont ensuite été introduites dans ces réactions, permettant ainsi de synthétiser des pyrrolopiperazines et d'autres molécules hétérocycliques polyfonctionnalisées énantioenrichies, toutes obtenues avec des rendements intéressants et des énantiosélectivités élevées.Ayant utilisé avec succès des β-Cétoamides α-Méthyléniques dans ces réactions multicomposantes, nous avons réalisé par ailleurs que leur simple addition de Michael sur des oléfines pauvres en électrons n'avait jamais été décrite en version organocatalysée. Nous avons donc étudié leur réaction avec des nitrooléfines en présence d’organocatalyseurs chiraux, et les produits attendus ont alors été obtenus avec de bons rendements et d'excellentes diastéréo- et énantiosélectivitésThis thesis focuses on the development of enantioselective multicomponent reactions with 1,3-Dicarbonyls in the presence of an organocatalyst, to synthesize fused polyheterocyclic motives.At first, we describe our initial results on an enantioselective multicomponent reaction with enals and simple primary amines. In view of the low enantioselectivities achieved, functionalized amines were then introduced in these reactions, thereby synthesizing enantioenriched pyrrolopiperazines and other polyfunctionalized heterocyclic molecules, all obtained with attractive yields and high enantioselectivities.Having successfully used methylene β-Ketoamides in these enantioselective MCRs, we realized also that their simple Michael addition to electron-Poor olefins had never been described in organocatalytic conditions. We therefore studied their reaction with nitroolefins in the presence of various chiral organocatalysts, and the expected products were pleasingly obtained with high yields, excellent diastereo- and enantioselectivities
11
Scansetti, Myriam. "Synthesis of pyroglutamic acid derivatives via double Michael addition reactions of alkynones." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4222.
Full textAbstract:
I. Synthesis of pyroglutamic acid derivatives via double Michael reactions of alkynones Pyroglutamic acids and their derivatives are common structural units of widespread chemical significance and they have been heavily utilised as building blocks for asymmetric synthesis. A new method for the synthesis of highly functionalised pyroglutamic acid derivatives, which consists in a Double Michael addition route that utilises amidetethered carbon diacids and aromatic alkynones as substrates, is here described. The reaction proceeds with good levels of trans-diastereoselectivity, provided that substoichiometric quantities of Mg(OTf)2 or Ni(acac)2 are employed. II. Michael additions combined with Friedel-Crafts cyclisations A domino Michael/Friedel-Crafts alkyation of aryl ethers with propargyl ketones was developed as a continuation of our double Michael additions. The reaction, here described, proceeds in good yield over two steps, when the aryl ethers and alkynones are treated with substoichiometric quantities of Yb(OTf)3 and heated to 100 oC in a microwave oven.
12
Abdelli, Abderrahmen. "Etude de la réactivité de quelques allylphosphonates β-éthoxycarbonylés." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLV028/document.
Full textAbstract:
La présence conjointe de plusieurs fonctions confère aux allylphosphonates β-éthoxycarbonylés une réactivité particulière. Ces derniers sont considérés comme d’excellents précurseurs pour l’accès à de nouveaux composés organophosphorés. Dans le présent travail, nous avons décrit, dans un premier temps, l’utilisation de ces adduits entant qu’accepteurs de Michael. En effet, nous avons effectué des additions conjuguées d ethiols, d’amines et d’anions énolates dans des conditions réactionnelles douces. Ces allylphosphonates ont été également utilisés pour la préparation d’une nouvelle famille de γ-lactames α,β-instaurés phosphono-méthylés.L’étape clé de cette synthèse est une addition conjuguée de nitroalcanes sur les allylphosphonates suivie d’une réaction de Nef..Les cétoesters ainsi obtenus sont convertis en lactames par action d’amines primaires. Des réactions d’arylations pallado-catalysées sur les allyphosphonates ont permis l’accès à des hétérocycles phosphonatés dérivant de lacoumarine, de la quinoléine et de la benzoxépinone. La synthèse de P-hétérocyclesde différentes tailles à partir des allylphosphonates a été aussi possible par la conversion du groupe phosphonate en phosphorochloridate. La réactivité de ce dernier vis-à-vis de différentes amines, a permis d’isoler une nouvelle famille de N,Phétérocyclesà 5, 7, 8 et 9 chaînons. La synthèse de P-hétérocycles à 6 chainons a été également décrite en réalisant des cyclisations dans les conditions de métathèse cyclisante (RCM) à partir d’un bisallylphosphonate et d’un bisallylphosphoramidate issus des mêmes précurseursDue to the joint presence of several functional groups, β-ethoxycarbonylatedallylphosphonates are considered as excellent precursors for the preparation of neworganophosphorus compounds. In the presentwork, we first described the use of suchphosphonates as Michael acceptors. Indeed, weperformed conjugated additions of thiols,amines and enolate-anion under mild reactionconditions. Allylphosphonates were also usedfor the preparation of a new family of phosphonomethyl α,β-unsaturated γ-lactams.The key step of this sequence is a conjugateaddition of nitroalkanes on allylphosphonates followed by a Nef reaction. Ketoester intermediaites were then convertedinto lactams by reaction with primary amines.Pd-catalyzed arylations on allylphosphonates allowed preparing phosphonated heterocyclesderived from coumarin, quinolinone andbenzoxepinone skeletons. The synthesis of Pheterocyclesof various sizes fromallylphosphonates was explored by theconversion of phosphonate inphosphorochloridate. The reactivity of the latterwith amines, allowed isolation of a new familyof 5-,7-, 8- and 9-membered N,P-heterocycles.The synthesis of 6-membered P-heterocycleshas also been described by performingcyclization under the conditions of a ringclosing metathesis (RCM) starting from bisallylphosphonates and bisallylphosphoramidates
13
Nadeau, Frédéric. "Le glycérol comme base structurale de coeurs de dendrimères obtenus par addition d'oxa-Michael sur des dérivés acryliques." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0357/document.
Full textAbstract:
Le glycérol est une molécule bio-sourcée, abondamment disponible, issue de la saponification des corps gras et de la transestérification des huiles végétales. Les travaux portent sur l'utilisation du glycérol comme base structurale de cœurs de dendrimère, en particulier par addition d'oxa-Michael sur des dérivés acryliques. La fonctionnalisation en surface de dendrimères par des motifs imidazolium est explorée afin d’obtenir un dendrimère liquide ionique (DLI) aux propriétés thermosensibles. Le chapitre bibliographique est consacré dans une première partie, aux méthodes de synthèse de dendrimère mettant en jeu des dérivés acryliques et à leurs applications et dans une seconde partie, aux travaux consacrés à l'addition oxa-Michael d'alcools sur des dérivés acryliques. Le deuxième chapitre porte sur les synthèses, à partir du glycérol, de la base structurale du cœur de dendrimère. La réaction d’acylation du glycérol par le chlorure d’acryloyle est présentée ainsi que les différentes constructions de dendrimères poly(estersulfure) à partir du triacrylate de glycérol. L’addition nucléophile du glycérol sur l’acroléine, l’acrylamide, des acrylates et l’acrylonitrile a été étudiée. Avec les acrylates, la réaction d'addition nucléophile est en compétition avec la réaction de transestérification, à l’exception de l'acrylate de t-butyle résistant en milieu basique. Avec l’acrylonitrile, la synthèse du 1,2,3-tricyanoéthylglycéryléther a pu être menée sans solvant, en 5 heures à température ambiante, en présence d’un catalyseur peu coûteux (la soude 4 mol %) avec un rendement de 88% et une pureté de 99% sans méthode de purification. Les intermédiaires de réaction mono- et di-cyanoéthylglycéryléther ont été caractérisés et ont permis un suivi cinétique de la réaction. La synthèse de dendrimères poly(amidoamine) à partir du 1,2,3-tricyanoéthylglycéryl éther fait l’objet du troisième chapitre : synthèse des générations G0 à G2,5, caractérisation des dendrimères. Des défauts de structure dus à une cyclisation intramoléculaire ont été mis en évidence par HRMS pour les générations entières et les dendrimères de demi-génération Gn+5 (n entier) sont purifiés par colonne chromatographique. Différentes voies de synthèse pour l’obtention d’un DLI à termini imidazolium sont présentéesGlycerol is a bio-based molecule, abundantly available, from the saponification of triglyceride and the transesterification of vegetable oils. The work described in this PhD thesis concerns the use of glycerol as structural base of dendrimer's core, in particular by oxa-Michael addition on acrylic derivatives. The surface functionalization of dendrimers by imidazolium units is explored in order to obtain an ionic liquid dendrimer (DLI) with thermosensitive properties. In the first part, the bibliographic chapter presents the methods of dendrimers synthesis involving acrylic derivatives and their applications and, in a second part, the work introduces the oxa-Michael addition of alcohols to acrylic derivatives. The second chapter deals with the synthesis of the structural base of the dendrimer core from glycerol. The reaction of acylation of glycerol with acryloyl chloride is presented as well as the various constructions of poly(estersulfide) dendrimers from glycerol triacrylate. The nucleophilic addition of glycerol to acrolein, acrylamide, acrylates and acrylonitrile has been studied. With the acrylates, the nucleophilic addition reaction is in competition with the transesterification reaction, with the exception of t-butyl acrylate, resistant in basic medium. With acrylonitrile, the synthesis of 1,2,3-tricyanoethylglycerylether was carried out without solvent in 5 hours at room temperature in the presence of an inexpensive catalyst (4 mol% sodium hydroxide) in a yield of 88% and purity of 99% without purification method. The mono- and di-cyanoethylglycerylether reaction intermediates were characterized and allowed kinetic monitoring of the reaction. The synthesis of poly(amidoamine) dendrimers from 1,2,3-tricyanoethylglycerylether is the subject of the third chapter: synthesis of generations G0 to G2,5 and characterization of dendrimers. The defects in the structure due to intramolecular cyclization have been demonstrated by HRMS for generations Gn and the half-generation dendrimers Gn+5 (n=0, 1, 2) were purified by chromatographic column. Several routes of synthesis for the synthesis of DLI with imidazolium termini are presented
14
Li, Zhijian. "Novel solid base catalysts for Michael additions." Doctoral thesis, [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976576759.
Full text
15
Nocentini, Benedetta. "Indagine su reazioni di sulfa-Michael di interesse in campo cosmetologico e sul trattamento ricostruttore del capello." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15849/.
Full textAbstract:
The aim of this work was to evaluate the reactivity of cysteinyl residues that can be found in damaged human hair with Michael acceptors under mild conditions and to gain information on the hair modifications occurring in hair bleached and then repaired with some commercial formulations. In some patents, the use of some molecules effective for repairing damaged hair is claimed. Their structure is compatible with the occurrence of Michael addition reactions, and the need of more detailed studies about the reaction mechanism and the effect on human hair of commercial products containing hair rebuilding agents has inspired this study. First, the investigation was focused to find Michael acceptors alternative to those claimed by the examined patents. As model reaction N-acetyl-L-cysteine was chosen as nucleophilic agent and different electrophiles, such as quinone- and maleic acid- derivatives, as well as a,b-unsatured ketones and esters were used. Subsequently we investigated, through Raman/IR spectroscopy and electronic scanning microscopy (SEM), on the effect of hair treatment with Michael acceptors studied in the first part and also some commercial hair rebuilding formulations.
16
Schmidt, Christian. "Darstellung konformativ eingeschränkter Glutaminsäurederivate durch Michael-Addition von chelatisierten Glycinesterenolaten." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=984726101.
Full text
17
Fuchs, Christian. "Studies towards the total synthesis of the Perophora viridis Trithiocane." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/8577.
Full textAbstract:
The influence of solvent and steric hindrance on the conversion of thiolsulfinates to trisulfides with hexamethyldisilathiane was investigated and a new polar mechanism, based on acceleration of the reaction by polar solvents and by fluoride ions, was proposed. The mono and dialkylation of 2,2-disubstituted 1,3-dithiane-1-oxides was investigated. Whereas those derived from menthone form only one diastereomer which cannot be alkylated further, those derived from acetone form two diastereomers. Only one of them can be alkylated further. Dehydration of the diastereomeric tertiary alcohols derived from directed aldol-reaction of γ-butyrolactones and methyl ketones yields diastereomeric conjugated enes in high yield and d.e. Michael-addition of benzyl thiols to these gives good yields and d.e. of the Michael-adducts. Deprotection of PMB-protected thiols with concomitant formation of disulfides was achieved by bromine in methanol or CH2Cl2. A seven-membered cyclic disulfide which contains the carbon backbone of the Perophora viridis trisulfide, albeit with two stereocentres in the incorrect configuration, was prepared.
18
Rosso, Helèna. "Addition conjuguée de réactifs organolithiés : application à la synthèse de produits naturels." Rouen, 2011. http://www.theses.fr/2011ROUES022.
Full textAbstract:
Mon projet de doctorat concerne principalement l'étude des additions d'oxa- et carba-Michael sur des composés carbonylés α,β-insaturés. Cette méthodologie a été étudiée pour la synthèse d'un fragment d'un produit naturel compliqué et de la verticipyrone. La thèse est répartie en deux volets. Une première partie correspond à la synthèse du fragment CD de l'azaspiracide I (une toxine que l'on retrouve dans certains crustacés) où quatre stratégies ont été appliquées afin d'obtenir cette structure. La deuxième partie du projet concerne la réactivité de l'α,α'-dimethoxy-y-pyrone. Nous avons donc développé une stratégie impliquant la désymmetrisation de α,α'-dimethoxy-y-pyrone par addition de Michael. Une synthèse en quatre étapes de la verticipyrone est présentée. Le passage clé comprend la désymmetrisation de α,α'-dimethoxy-y-pyrone 1 par l'addition conjuguée d'un agent allylant et la cross-métathèse de la pyrone allylé obtenue avec une oléfine appropriée. L'anion généré lors de l'addition de l'agent allylant sur 1 a été piégé avec divers électrophiles afin d'obtenir de manière régio- et stéréosélective de nouvelles molécules appartenant à la famille des α'-methoxy-y-pyrone. Leurs bioactivités ont été évaluéesMy Ph. D. Project was mainly focused on the oxa- and carba- Michael additions onto α,β-unsaturated carbonyl compounds. This methodology was investigated for the syntheses of a fragment of a complex natural target compound and natural products. This work has been divided in two parts. In the first part, the partial synthesis of the CD framework of the (-)-azaspiracid I (a dangerous neurotoxic molecule contained in shellfish) was investigated and four strategies were devised in order to synthesize this structure. Instead, the second part explores the reactivity of α,α'-dimethoxy-y-pyrone in order to obtain unsaturated α'-methoxy-y-pyrone plyketides derivatives. For that purpose, we have developed a strategy involving the desymmetrization of α,α'-dimethoxy-y-pyrone by Michael addition. A four-step verticipyrone synthesis is presented. The key steps included the desymmetrization of α,α'-dimethoxy-y-pyrone 1 by conjugated addition with an allylating agent and the cross-metathesis of the allylated pyrone with the proper olefin. Taking advantage of the strategy of the one-pot desymmetrization of pyrone 1 by the addition of an allylating agent, the anion generates during this addition was trapped with an electrophile in order to obtain, in a regio and stereoselective manner, new molecules belonging to the α'-methoxy-y-pyrone family. The bioactivities of these new molecules were also evaluated
19
Ozturk, Gozde. "Topology and Telechelic Functionality Control in Polyester Design." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/28030.
Full textAbstract:
Research efforts have focused on synthesis of linear, long-chain branched, and novel crosslinked polyesters for applications spanning from pressure sensitive adhesives to biomedical applications. Altering polymer topology and functionality using different synthetic strategies was enabled tailoring the thermomechanical, rheological, and adhesive properties of polyesters. The synthesis and characterization of linear, long-chain branched, and crosslinked networks are described focusing on the structure-property relationships.
Aliphatic low-Tg polyesters with linear and long-chain branched topology were synthesized using melt polycondensation for pressure sensitive adhesive applications. Relationships between molecular weight, polymer composition, and adhesive performance were investigated. Melt rheological studies and the characterization of adhesive properties indicated that adhesive performance was enhanced with increasing molecular weight. Moreover, a series of long-chain branched low-Tg polyester were investigated to determine the influence of branching and molecular weight. Tailoring the degree of branching enabled the control of rheological and adhesive properties. Characterization of adhesive properties revealed that long-chain branched polymers displayed an enhanced cohesive strength. In addition, utilization of different comonomer compositions allowed tailoring thermal and adhesive properties of low-Tg polyesters over a wide range.
Biodegradable networks were synthesized for the first time using base-catalyzed Michael addition of acetoacetate functionalized polyesters with acrylates. Linear and star-shaped poly(caprolactone) (PCL) oligomers with different molecular weights were functionalized and crosslinked. Thermomechanical properties were evaluated as a function of precursor molecular weight and crosslink density. The glass transition temperature and the extent of crystallinity of the networks were dependent on the molecular weight of the PCL segment. Moreover, dynamic mechanical analysis (DMA) indicated that molecular weight of the oligomeric precursors influenced the plateau modulus of the networks as a result of the differences in crosslink density of the networks. In addition, covalently crosslinked networks were synthesized from Michael addition reaction of acetoacetate-functional oligomeric poly(trimethylene succinate)s and poly(trimethylene adipate)s with neopentylglycol diacrylate. The oligomeric polyesters with telechelic hydroxyl functionality were synthesized from renewable monomers, adipic acid, succinic acid, and 1,3-propanediol using melt polycondensation. The molecular weights of the precursors were varied systematically to probe the influence of molecular weight on thermomechanical properties of the networks. The extent of crystallinity and mechanical properties were dependent on the molecular weight of the oligomeric polyester precursors which also controlled crosslink density. Moreover, Michael addition chemistry was utilized to crosslink low-Tg polyesters to improve cohesive strength for PSA applications. In order to determine the influence of temperature and catalyst levels, crosslinking reactions were monitoring using measurement of loss and storage moduli during the reaction. Networks having different levels of gel fractions were investigated to elucidate the influence of degree of crosslinking on thermomechanical and adhesive properties of low-Tg polyesters.Ph. D.
20
Gendron, Thibault. "Synthesis and evaluation of the antiparasitic activity of diarylideneacetones and their related thiopyranone and S-oxide prodrugs." Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAF064/document.
Full textAbstract:
La trypanosomiase humaine africaine, la maladie de Chagas et les leishmanioses sont des maladies parasitaires qui représentent un problème majeur de santé publique dans de nombreux pays et notamment ceux en voie de développement. Afin de trouver de nouveaux candidat-médicaments contre ces parasites, deux séries chimiques ont été étudiées : les diarylidèneacétones et les 2,6-diaryl-4H-tetrahydrothiopyranones.Précédemment initiée au laboratoire, l'étude approfondie de la série diarylidèneacétone a nécessité la mise au point et l'optimisation de protocoles. Une nouvelle méthodologie de synthèse des (hétéro)diarylidèneacétones dissymétriques par palladocatalyse a ainsi été développée en collaboration avec le Pr. T. J. Müller (Université de Düsseldorf). En dépit d'excellentes activités antiparasitaires, la plupart des diarylidèneacétones synthétisées se sont révélées trop toxiques sur les cellules humaines.Les 2,6-diaryl-4H-tétrahydrothiopyranones et leurs S-oxydes ont été conçues pour résoudre ce problème de toxicité. Agissant comme prodrogues, ces molécules sont susceptibles de régénérer les diarylidèneacétones parentes par β-élimination du groupement soufré intracyclique. Peu décrite dans la littérature, la synthèse diastéréosélective de ces structures a été intégralement mise au point et généralisée à de nombreuses substitutions. Les résultats obtenus prouvent que la toxicité des produits a été grandement diminuée tout en maintenant une activité antiparasitaire importante, ce qui valide l'approche de la stratégie prodrogueHuman African trypanosomiasis, Chagas disease and leishmaniasis are parasitic diseases that significantly affect the populations and thus the economy of many developing countries. With the aim of developing new therapeutic agents to cure these diseases, we focused our research on two series: the diarylideneacetone and the 2,6-diaryl-4H-tetrahydrothiopyranone series.To complete and expend preliminary results that had been previously obtained in our laboratory, a generalization and an optimization of the protocols was intended. Thus, a novel Palladium-catalyzed synthesis of (hetero)dissymmetric diarylideneacetones was developed and optimized in collaboration with Prof. T. J. Müller (University of Düsseldorf). In spite of excellent antiparasitic activities, most of the diarylideneacetones were toxic toward human cells.2,6-Diaryl 4H-tetrahydrothiopyranones and their related S-oxides were designed to cope with major toxicity issues. Acting as prodrugs, these molecules are prone to undergo β-elimination of the sulfurated intracyclic group, regenerating the parent diarylideneacetone. The diastereoselective synthesis of this scaffold is not extensively described in the literature. Consequently, novel diastereoselective methodologies have been developed and generalized to a wide panel of substitution patterns. Results of the biological assays demonstrated that sulfide and S-oxide prodrugs displayed a lowered toxicity while the potency was maintained, thus confirming the validity of the prodrug strategy
21
Fukata, Yukihiro. "Studies on Asymmetric Hetero-Michael Addition Utilizing Various Modes of Organocatalytic Activation." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215551.
Full text
22
Ay, Sefer. "Synthese und Anwendung von [2.2]Paracyclophanliganden in der asymmetrischen konjugaten Addition." Berlin Logos-Verl, 2008. http://d-nb.info/992809320/04.
Full text
23
Seingeot, Adeline. "Utilisation des liquides ioniques dans des réactions à économies d'atomes : l'addition de Michael et la cycloaddition 1,3-dipolaire." Thesis, Aix-Marseille 3, 2011. http://www.theses.fr/2011AIX30058.
Full textAbstract:
L'une des préoccupations de la chimie moderne est de développer des procédés éco-compatibles : une tendance consiste à remplacer les solvants organiques par les Liquides Ioniques (LI). Ainsi ces travaux décrivent l'utilisation des LI dans deux réactions à économie d'atomes : l'addition de Michael et la réaction de cycloaddition 1,3-dipolaire catalysée (ou non) par un sel de cuivre (CuAAC). La première partie des travaux relate l'emploi de Liquides Ioniques Super-Acides (LISA), connus pour générer une activation électrophile. Une optimisation du LISA a été effectuée sur une réaction-modèle, puis l'application à d'autres électrophiles et nucléophiles a été étudiée. La pureté du LISA influe sur la chimiosélectivité : s’il est partiellement hydrolysé, la réaction d'annélation de Robinson devient prépondérante. La version asymétrique du processus a été abordée, montrant qu'il est possible d'obtenir un excès énantiomérique à partir de dérivés d'acides aminés. La seconde partie de l'étude a permis de mettre au point une synthèse de (triazolylméthyl)vinylphosphonates à partir d'un acétoxyméthylvinylphosphonate selon une procédure monotope reposant sur la cycloaddition 1,3-dipolaire dans différents LI. Nous avons ensuite montré que le LI joue aussi le rôle d'activateur pour cette réactionIn the context of sustainable chemistry, an alternative to conventional organic solvents is the use of ionic liquids. These works reported here aims to describe the use of ionic liquids (IL) in two atoms economy reactions, namely the Michael addition reaction and 1,3-dipolar cycloaddition catalyzed (or not) by a copper salt (CuAAC). In the first part of the work reports the use of Super-Acid Ionic Liquids (SAIL), which initiate an electrophilic activation. After optimization of SAIL on a reaction model, application to other electrophiles and nucleophiles is discussed. The purity of SAIL affects the chemioselectivity: if the SAIL is partially hydrolyzed, a Robinson annulation predominates. The asymmetric version of the process is investigated, showing that it is possible to carry out an enantioselective reaction with amino acid derived SAIL. The second part of the study deals with setting up an original synthesis of (triazolylmethyl)vinylphosphonate from acetoxymethylvinylphosphonate using a one-pot procedure involving a 1,3-dipolar cycloaddition in different LI. We further showed that the ionic liquid can also act as an activator for this reaction
24
Moreno, Rueda Maryluz. "Hetero-michael addition to sunflower oil derivatives as precusors of polymeric materials." Doctoral thesis, Universitat Rovira i Virgili, 2013. http://hdl.handle.net/10803/128506.
Full textAbstract:
El objetivo principal de esta tesis es la síntesis de polímeros empleando aceites vegetales como reactivos de partida. En la primera etapa, se prepararon diferentes polímeros retardantes a la llama termoestables por modificación química de aceite de girasol alto oleico y posterior polimerización vía adición de Michael de fosforo and nitrógeno como nucleófilos. En la segunda etapa, se exploró la utilización de la adición de Michael de tioles (nucleófilos) en la síntesis y desarrollo de nuevos monómeros a partir de derivados del aceite de girasol alto oleico y del oleato de metilo. Posteriormente los monómeros provenientes del oleato de metilo se utilizaron en la obtención de poliésteres, estos poliésteres se modificaron para incrementar sus aplicaciones en el campo biológico o biomédico. Los monómeros obtenidos del aceite de girasol alto oleico se utilizaron en la síntesis de materiales termoestables y en el desarrollo de un material nanocompuesto con nanopartículas de celulosa. Como conclusión general: Se desarrollaron exitosamente polímeros empleando aceite de girasol alto oleico y sus derivadosAbstract The principal objective of this thesis is the synthesis of polymeric materials from vegetable oils derivatives. In the first step different flame retardant thermosetting polymers were synthesized through chemical modifications of commercial high oleic sunflower oil followed byaddition and crosslinking via phospha and aza-Michael addition. In the second step lineal polyesters and thermosets were synthesis through thiol-Michael addition to sunflower oil derivatives. The lineal polyesters were modified to wide their biology or biomedical applications. Furthermore the development a novel nanocomposite with cellulose nanocrystal material was carrie out. As general conclusion polymers from vegetables oil derivatives were development successfully
25
Otto, Andreas. "Ringtransformationen an chiralena-Alkylidenlactonen." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 1999. http://dx.doi.org/10.18452/14473.
Full textAbstract:
Ziel dieser Arbeit ist die Synthese neuer optisch aktiver Hydroxyalkylheterocyclen durch Ringtransformationen von chiralen -Alkylidenlactonen. Hierzu wurden letztere gezielten Additionen von Binucleophilen, 1,3-dipolaren Cycloadditionen, Cupratadditionen und Epoxidierungsreaktionen unterworfen. Die erhaltenen Produkte konnten durch weitere gezielte Folgereaktionen, Spaltungen oder Reaktionen mit Nucleophilen zu interessanten enantiomerenreinen Hydroxyalkylheterocyclen umgesetzt werden. Eine Deutung der acyclischen Seitendifferenzierung gelang mit Hilfe des antiperiplanaren Effektes und des inside alkoxy effects. Umsetzungen mit Hydrazinen führten in guten Ausbeuten zu trans-Hydroxyalkyl-3-pyrazolidinonen. Aus Nitromethan und -Alkylidenlactonen erhält man DBU-katalysiert Nitroethyllactone die sich unter hydrogenolytischen Reaktionsbedingungen zu trans-3-Hydroxyalkyl-2-pyrrolidinonen ringtransformieren lassen. Über o-Aminothiophenoladditionen und Ringtransformationen werden enantiomerenreine 3-(2-Hydroxyalkyl-2,3-dihydro-1,5-benzothiazepin-4(5H)-one erhalten, die neuartige Analoga der Pharmaka Dilthiazem und Thiazesim darstellen. Neue D1-Pyrazoline entstehen durch 1,3-dipolare Cycloadditionen von Diazoalkanen an -Alkylidenlactone. Durch photolytische Extrusion von Stickstoff werden neue chirale Cyclopropanderivate erhalten. Enantiomerenreine , -Diaminosäurederivate werden durch hydrogenolytische N-N-Bindungsspaltung der D1-Pyrazoline generiert. Über Epoxidierung der -Alkylidenlactone mittels Dimethyldioxiran und Umsetzung der erhaltenen Oxirane mit verschiedenen N- und S-Nucleophilen und anschließender Ringtransformation, ist ein Zugang zu Benzothiazepin-4(5H) -on, 1,5-Benzodiazepin-2-on, 1,4-Thiazepan-5-on, Thiomorpholin-2-on, 1-Phenyl-2-acetidion sowie über Lithium-Halogenaustausch-Reaktion zu 2-Hydroxy-2-hydroxyethyl- thiochromen-4-on erarbeitet worden. Mit Organokupferverbindungen gelingt hochregioselektiv die 1,4-Addition. Unter Bedingungen der Iodlactonisierung werden aus den Addukten neuartig substituierte -Butyro- und -Valerolactone erhalten.The thesis is focused on the synthesis of new optically active hydroxyalkyl heterocycles by ring-chain-transformation of chiral -alkylidenlactones. The latter were subjected to specific additions of binucleophiles to 1,3-dipolare cycloadditions to addition of cuprates and to epoxidation. The product obtained could be further applied in the synthesis of interesting enantiomerically pure hydroxyalkyl heterocycles by specific reactions like ring-cleavage or reactions with nucleophiles. The acyclic side differentiation could be explained with the help of the antiperiplanar effect and the inside alkoxy effects. Reactions with hydrazines led to trans-hydroxyalkyl-3-pyrazolidinones in good yields. Nitroethyllactones were obtained from -alkylidenlactones and nitromethane under DBU-catalysis. In a following step they are ring-transformed into trans-3-hydroxyalkyl-2-pyrrolidinones by hydrogenation. Enantiomerically pure 2-hydroxyalkyl-2,3-dihydro-1,5-benzothiazepin-4-(5H)ones could be prepared by addition of o-aminothiophenol and following ring-chain-transformation. These compounds represent novel analogs of the drugs Dilthiazem™ and Thiazesim™. Novel D1-pyrazoline results from 1,3-dipolare cycloadditions of -alkylidenlactone with diazoalkanes. New chiral derivatives of cyclopropanes were obtained by photolytic extrusion of nitrogen. Enantiomerically pure ,-diaminoacid derivatives were generated by hydrogenolytic cleavage of the N-N-bond of the pyrazolines. Epoxidation of -alkylidenlactones with dimethyldioxirane and opening of the oxirane ring obtained by various N- and S-nucleophiles provided new methods for the synthesis of benzothiazepin-4(5H)-one, 1,5-benzodiazepin-2-one, 1,4-thiazepan-5-one, thiomorpholin-2-one and 1-phenyl-2-acetidione. 2-Hydroxy-2-hydroxyethyl-thiochromen-4-one could be obtained by lithium-halogens exchange reaction. The 1,4-additions of organocuprates to -alkylidenlactones succeeded with high regioselectivity. Novel substituted [gamma]-butyro- and -valerolactones were obtained by iodolactonisations of these adducts.
26
Mulliner, Denis. "Quantenchemische Modellierung der Thiol-Addition an Michael-Akzeptoren zur quantitativen Vorhersage ihrer elektrophilen Reaktivität und aquatischen Toxizität." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-141274.
Full textAbstract:
Die kovalente Bindung von elektrophilen körperfremden Stoffen an nukleophile Zentren in Peptiden und Proteinen ist der initiierende molekulare Schritt einer Vielzahl von Erkrankungen und toxischen Prozessen. Für a,b-ungesättigte Aldehyde, Ketone und Ester, die sogenannten Michael-Akzeptoren, spielt dabei die Reaktion mit endogenen Thiolen eine entscheidende Rolle. Für diese Stoffklasse ermöglicht die Quantifizierung der Thiolreaktivität (als logaritmische Geschwindigkeitskonstante zweiter Ordnung der Reaktion des Michael-Akzeptors mit dem Tripeptid Glutathion (GSH), log kGSH) eine Vorhersage der akuten aquatischen Toxizität gegenüber den Ciliaten Tetrahymena Pyriformis (quantifiziert als logaritmische 50%-Effekt-Konzentration (effect-concentration, EC) der Wachstumsinhibition, log EC50).
Zum besseren Verständnis der an diesen Prozessen beteiligten Reaktionen wurden in dieser Arbeit mehrere mögliche Mechanismen der Addition von Methylthiol an a,b-ungesättigte Carbonylverbindungen quantenchemisch anhand ihrer Übergangszustände untersucht. Dabei lag der Fokus unter anderem auf der Identifikation einer Modellreaktion, deren Barriere eine quantitative Vorhersage der Thiolreaktivität ermöglicht. Entsprechende Regressionsmodelle wurde an experimentelle Daten angepasst. Auf der Basis der berechneten elektrophilen Reaktivität log kGSH und der Hydrophobie (quantifiziert als logarithmischer Oktanol/Wasser-Verteilungskoeffizient, log Kow) wurden Stoffklassenspezifische Regressionsmodelle zur Toxizitätsvorhersage entwickelt und für die Untergruppe der Ester eine Modell-Suite etabliert.
27
Ji, Mingzhe. "Explorations with optically active, cage-annulated crown ethers." Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc4207/.
Full textAbstract:
A variety of optically active macrocyclic crown ethers that serve as "host" systems that are capable of differentiating between enantiomeric "guest" molecules during host-guest complexation have been prepared via incorporation of chiral elements into the crown ring skeleton. The ability of these crown ethers to recognize the enantiomers of guest salts, i.e., (+) a-methyl benzylamine and to transport them enantioselectively in W-tube transport experiments were studied. The ability of these crown ethers to perform as chiral catalysts in an enantioselective Michael addition was studied. The extent of asymmetric induction, expressed in terms of the enantiomeric excess (%ee), was monitored by measuring the optical rotation of the product and comparing to the literature value.
28
Simpson, Alain. "Nickel-catalysed asymmetric Michael additions of 2-acetylazaarenes to nitroalkenes." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/17925.
Full textAbstract:
Azaarenes are of widespread chemical significance, being present in numerous chiral, biologically active natural products, and serving as building blocks for the discovery of new medicines, agrochemicals, and functional molecules. Consequently, the development of new methods to prepare chiral azaarene-containing compounds is an important goal. The Lam group and others have previously demonstrated the synthetic utility of azaarenes as activating groups in a variety of catalytic asymmetric processes, which are summarised in Chapter 1. Chapter 2 presents a recent achievement in this area: the development of a mild and highly enantioselective conjugate addition of acetylazaarenes to nitroalkenes, under nickel catalysis, to afford densely functionalised products. The reaction scope includes a broad range of acetylazaarenes as well as (hetero)aromatic and aliphatic nitroalkenes. When α-nitroacrylate esters are employed as conjugate acceptors, products bearing a quaternary stereogenic centre are formed in high yield and with excellent enantioselectivity. The methodology is easily scalable, allowing multigram preparations to be carried out with catalyst loadings of 1 mol% without loss of yield or enantioselectivity. Further transformations of the products, including diastereoselective transfer hydrogenation, are briefly described. Finally, Chapter 3 gives an overview of unsuccessful efforts to develop routes to α-sulfonyl organoboron compounds, for subsequent use in ate complex homologation chemistry, via catalytic asymmetric conjugate addition processes.
29
Lombardi, Federico. "Computational study on the asymmetric aminocatalysed Michael addition reaction of cyclohexanone to trans–β–nitrostyrene." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23186/.
Full textAbstract:
Asymmetric organocatalysed reactions are one of the most fascinating synthetic strategies which one can adopt in order to induct a desired chirality into a reaction product. From all the possible practical applications of small organic molecules in catalytic reaction, amine–based catalysis has attracted a lot of attention during the past two decades. The high interest in asymmetric aminocatalytic pathways is to account to the huge variety of carbonyl compounds that can be functionalized by many different reactions of their corresponding chiral–enamine or –iminium ion as activated nucleophile and electrophile, respectively. Starting from the employment of L–Proline, many useful substrates have been proposed in order to further enhance the catalytic performances of these reaction in terms of enantiomeric excess values, yield, conversion of the substrate and turnover number. In particular, in the last decade the use of chiral and quasi–enantiomeric primary amine species has got a lot of attention in the field. Contemporaneously, many studies have been carried out in order to highlight the mechanism through which these kinds of substrates induct chirality into the desired products. In this scenario, computational chemistry has played a crucial role due to the possibility of simulating and studying any kind of reaction and the transition state structures involved. In the present work the transition state geometries of primary amine–catalysed Michael addition reaction of cyclohexanone to trans–β–nitrostyrene with different organic acid cocatalysts has been studied through different computational techniques such as density functional theory based quantum mechanics calculation and force–field directed molecular simulations.
30
Richard, Mylène. "Les exo-glycals activés pour la synthèse de dérivés saccharidiques complexes : application à la préparation de glycoamino acides et de peptidomimétiques." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0133/document.
Full textAbstract:
Ces travaux s’articulent autour de dérivés saccharidiques de type exo-glycals ou C-glycosides pour lesquels de nouvelles méthodologies synthétiques ainsi que des applications dans le domaine de la biologie ont été développées. Dans un premier temps, l’addition de nucléophiles soufrés et carbonés sur le carbone anomérique de différents exo-glycals activés a été réalisée, permettant un accès efficace à de nouveaux S-glycosides tertiaires ainsi qu’à des γ-glycoamino acides anomériques. Ces derniers ont été utilisés pour l’élaboration de peptides linéaires mixtes α/γ dont les propriétés de structuration ont ensuite été étudiées par RMN, IR, CD et modélisation moléculaire. De nouvelles plates-formes glycopeptidiques multifonctionnelles ont été préparées par cyclisation de ces peptides. Dans un second temps, le développement de peptidomimétiques ciblant le récepteur neuropiline-1, impliqué dans l’angiogenèse tumorale, a été entrepris. En s’appuyant sur des études de modélisation moléculaire, certains composés ont montré une bonne affinité pour le récepteur NRP-1 et l’un des composés a montré des propriétés prometteuses pour l’inhibition de la formation de tubulesThis work is focused on the development of new synthetic pathways for exo-glycals functionalization and synthesis of bioactive compounds. The first part of this manuscript describes the efficient preparation of new tertiary S-glycosides and γ-glycoamino acids via Michael addition of thiols derivatives and carbanions on anomeric carbon of exo-glycals. The obtained γ-glycoamino acids were then incorporated in α/γ mixed peptides and their structural properties were studied by NMR, IR, CD and molecular modelling studies. Furthermore, cyclic multivalent platforms were built by intramolecular cyclization of these entities. The second part of the manuscript concerns the elaboration of peptidomimetics targeting neuropilin-1 receptor, implicated in tumor angiogenesis. Based on molecular modeling studies, some compounds showed interesting binding affinity for NRP-1 receptor and one of them displayed promising properties toward inhibition of tubule formation
31
Flores, Ferrándiz Jesús. "Chiral Aminocarbamates Derived from trans-Cyclohexane-1,2-Diamines as Organocatalysts in Conjugate Addition Reactions." Doctoral thesis, Universidad de Alicante, 2017. http://hdl.handle.net/10045/73589.
Full textAbstract:
The thesis has been divided in two chapters: Chapter I describes the preparation of primary-amine monocarbamates from enantiopure trans-cyclohexane-1,2-diamines and their use as chiral organocatalysts in the enantioselective Michael addition reaction of aldehydes and ketones to maleimides, to synthesize enantiomerically enriched substituted succinimides. In the conjugate addition reaction of aldehydes to maleimides in conventional volatile organic solvents, it has been found that these organocatalysts are able to generate both enantiomers of the corresponding succinimide using only one enantiomeric form of the catalyst, just by changing the polarity of the solvent. Theoretical calculations justify the mechanism through which this inversion of enantioinduction occurred. In addition, these organocatalysts were used in the enantioselective Michael addition reaction of aldehydes to maleimides, using Deep Eutectic Solvents (DES) as recyclable and environmentally sustainable reaction medium, yielding the corresponding succinimides with excellent yields and high enantioselectivities (up to 94%). The succinimides can be extracted from the DES, which retains the chiral organocatalyst, allowing to reuse both solvent and catalyst. Moreover, the conjugate addition of ketones to maleimides using conventional solvents, allows obtaining the corresponding succinimides with excellent yields but with moderate enantioselectivities (up to 66%). Chapter II shows the results obtained in the enantioselective Michael addition reaction of aldehydes and ketones to nitroalkenes, using the former trans-cyclohexane-1,2-diamine-derived aminocarbamates as chiral organocatalysts, obtaining enantioenriched γ-nitrocarbonyl compounds. In the conjugate addition of isobutyraldehyde to nitroalkenes, the corresponding γ-nitroaldehydes were obtained with enantioselectivities up to 84%. In addition, the enantioselective conjugate addition reaction of ketones to nitroalkenes allowed to obtain interesting γ-nitroketones with high enantioselectivities (up to 96%). Theoretical calculations justify the mechanism involved during this enantioselective process.
32
Sanchez, Duque Maria del Mar. "Nouvelles applications de l'addition de Michael organo catalysée dans des réactions domino multicomposés énantiosélectives." Thesis, Aix-Marseille 3, 2011. http://www.theses.fr/2011AIX30047.
Full textAbstract:
Au cours de ce travail, nous nous sommes intéressés à explorer le potentiel d’une réaction multicomposés initiée par une addition de Michael conduisant à des dérivés de 2,6-DABCO. Dans ce contexte, nous avons tout d’abord étudié l’étendue de la réaction en modifiant les différents partenaires et paramètres réactionnels. Dans le but de rendre ce procédé plus éco-compatible, l’utilisation de liquides ioniques recyclables a aussi été étudié. Dans certains cas, les liquides ioniques ont permis de s’affranchir du solvant organique toxique et du catalyseur hétérogène de la réaction. Enfin, afin de mettre en œuvre une synthèse multicomposés énantiosélective de 2,6-DABCO, nous avons été amenés à développer une nouvelle méthodologie d’addition de Michael énantiosélective organocatalysée de béta-cétoamides sur des dérivés carbonylés alpha,béta-insaturés. Ainsi, des adduits comportant un centre stéréogène quaternaire entièrement carboné ont pu être obtenus avec de bons rendements et des excès énantiomériques qui atteignent 99%. Une étude sur la réactivité de ces adduits nous a permis d’accéder à différentes familles de composés poly(hétéro)cycliques optiquement actifs d’un grand intérêt synthétiqueIn this work, we explored the potential of a Michael addition-initiated multicomponent reaction leading to 2,6-DABCO derivatives. In this context, we first studied the scope of the reaction by changing the partners and the parameters of the reaction. In view of making the process more eco-friendly, the use of ionic liquids was also investigated and found that in some cases, the ionic liquids could replace the toxic organic solvent and the heterogeneous catalyst of the reaction. Finally, the implementation of an enantioselective multicomponent synthesis of 2,6-DABCO led us to develop a new methodology of an organocatalytic enantioselective Michael addition of beta-ketoamides to alpha, beta-unsaturated carbonyls. In this way, adducts containing an all-carbon quaternary stereocenter were obtained in good yields and high to excellent enantiomeric excesses (up to 99%). The study of the reactivity of these adducts allowed the access to different families of optically active poly(hetero)cyclic compounds of high synthetic interest
33
Raimondi, Wilfried. "Nouvelles transformations organocatalysées énantiosélectives à partir de composés dicarbonyles et de nitroalcènes." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4350/document.
Full textAbstract:
Au cours de ces travaux, nous nous sommes intéressés au développement de nouvelles transformations combinant des outils modernes de la synthèse organique que sont les MBFT's (Multiple Bond-Forming Transformations) et l'organocatalyse et impliquant la réactivité des nitroalcènes. Nous avons dans un premier temps élaboré une réaction consécutive hautement stéréosélective Michael – Hétérocyclisation [3+2] – Fragmentation. Au cours de ce processus, deux liaisons C–C, une liaison C–O et un cycle sont formés afin de former des cyclopentanoximes optiquement actifs portant jusqu'à trois centres stéréogènes pouvant être convertis en hydroxylamines ou en indoles. Nous avons ensuite exploité le potentiel pro-nucléophile des composés 1,2-dicarbonylés lors de l'élaboration des premières additions de Michael organocatalysées diastéréo- et énantiosélectives de 1,2-cétoesters et de 1,2-cétoamides sur des nitrooléfines. Les adduits obtenus constituent des plateformes synthétiques vers la construction de carbo- et d'hétérocycles à cinq et six chaînons possédant une large diversité fonctionnelle. Ces travaux ont conduit au développement d'une transformation domino impliquant divers composés 1,2-dicarbonylés et nitroalcènes halogénés afin d'accéder de manière rapide et efficace à des 2-carbonyl- et 2-phosphorylfuranes dont les voies de synthèse sont peu courantes dans la littérature. Les premiers résultats très encourageants quant à l'obtention de furanes atropoisomères ouvrent les portes à une version asymétrique de cette méthodologieThis work focused on the development of novel transformations combining MBFT's and organocatalysis, the latest powerful tools of organic synthesis, and involving the reactivity of nitroalkenes. We first developed a highly stereoselective consecutive Michael – [3+2] Heterocyclisation – Fragmentation reaction where two C–C bonds, one C–O bond and a cycle are formed to make optically active cyclopentanoximes bearing up to three stereocenters. These products can be converted into hydroxylamines or indoles. We then exploited the nucleophilic potential of 1,2-dicarbonyl compounds in the design of the first organocatalyzed diastereo- and enantioselective Michael additions of 1,2-ketoamides and 1,2-ketoesters onto nitroalkenes. The corresponding adducts are valuable synthetic platforms towards the synthesis of five- and six-membered carbo- and heterocycles with wide functional variety. This work led to the development of a domino transformation involving 1,2-dicarbonyl compounds and halogenated nitroolefines to efficiently access 2-carbonyl- and 2-phosphorylfuranes whose reported synthetic pathways remain rare. The first encouraging trials carried out to make atropisomers enable a potential asymmetric version of this methodology
34
Mehdar, Yassin Taleb. "Synthesis and applications of proline derived guanidine catalysts in asymmetric Michael addition reactions." Thesis, Bangor University, 2017. https://research.bangor.ac.uk/portal/en/theses/synthesis-and-applications-of-proline-derived-guanidine-catalysts-in-asymmetric-michael-addition-reactions(4904fca7-0964-4403-92e5-ed2efe888e85).html.
Full textAbstract:
This thesis reports the preparation of a range of guandine and guanidinium species used as catalysts for asymmetric Michael additions. The most successful of these were based on the generalized structure I (R = Me, iPr, Bn, Cy; R1, R2 = H, Me, Ph, 1,2-phenyl, R3 = Me, Bz, Cbz, Ph) and were effective catalysts of the reaction between of 2-nitrostyrene 52 and 93 leading to yields 35-99 % and up to 44 % enantiomeric excess for the product 94. Similar reactions using diethyl malonate or 2,4-pentanedione were also catalysed however these were less successful and generally led to low enantiomeric excesses and the formation of unidentifiable polymeric byproducts. X-ray crystallographic structures were determined for several of these compounds and the hydrogen bonding patterns observed were used to speculate on the mechanism of the reaction and the magnitude of the asymmetric induction.
35
Calderari, Giorgio. "Regioselektive und asymmetrische Michael-Additionen an Nitro-Olefine /." [S.l.] : [s.n.], 1985. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=7841.
Full text
36
Léger, Frédéric. "Additions d'énamines β-lithiées sur des esters α, β-éthyléniques. Nouvelles propriétés des énamines β-halogénées." Rouen, 1996. http://www.theses.fr/1996ROUES051.
Full textAbstract:
Les énamines β-lithiées sont obtenues par bromation des énamines puis échange halogène-métal et réagissent directement avec les esters α, β-éthyléniques exclusivement en 1,4 conduisant après hydrolyse aux énaminoesters correspondants. Ces composés sont obtenus avec de bons rendements et présentent une rétention de configuration par rapport aux énamines β-bromées de départ. L'énolate intermédiairement formé a été condensé sur l'iodure de méthyle conduisant à la création d'un carbone stéréogénique supplémentaire. Dans ce cas les nouveaux énaminoesters sont obtenus avec une excellente diastéréosélectivité. L'hydrolyse des énaminoesters conduit, selon les conditions utilisées, aux cétoesters ou aux cétoacides correspondants avec en général une très bonne diastéréosélectivité. En utilisant des énamines β-lithiées achirales sur des esters α, β-éthyléniques d'alcool chiral, les excès diastéréoisomériques ont été moyens. Par contre la réaction de Michael entre une énamine β-lithiée chirale et le crotonate de tertiobutyle conduit a une complète diastéréoselectivité au niveau de l'énaminoester. Dans les conditions de réaction de Heck (Pd(OAc)2, PPh3, NEt#3, CH3CN), les énamines beta-halogénées ont été réduites en amines tertiaires avec des rendements corrects. L'utilisation d'énamines β-halogénées à reste aminé chiral conduit aux amines tertiaires chirales correspondantes. L'agent de réduction est vraisemblablement la triéthylamine. La deracémisation d'aldéhydes α-substitués par l'intermédiaire d'énamines β-substituées chirales conduit à des aldéhydes α-substitués optiquement actifs. Les différents paramètres de la réaction ont été étudiés et ont permis d'atteindre des excès énantiomériques de 60%.
37
Hoffmann, Guillaume. "Mise au point de nouveaux descripteurs théoriques pour la réactivité chimique Can molecular and atomic descriptors predict the electrophilicity of Michael acceptors? On the influence of dynamical effects on reactivity descriptors Predicting experimental electrophilicities from quantum and topological descriptors : a machine learning approach Electrophilicity indices and halogen bonds : some new alternatives to the molecular electrostatic potential." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR042.
Full textAbstract:
L’étude des descripteurs de réactivité globaux, locaux et non locaux d'un système réactif est d’une importance capitale afin de comprendre la réactivité de la totalité des processus chimiques lors d’une réaction. Le but de cette thèse a ainsi été de mettre au point de nouveaux descripteurs de réactivités, ainsi que des modèles de prédiction basés sur ces derniers, afin d’étudier la réactivité chimique. Les principale méthodes théoriques employées ont été la Théorie de la fonctionnelle de la densité conceptuelle (CDFT) et la théorie quantique « Atoms in Molecules » (QTAIM) qui sont toutes deux basées sur la densité électronique. Notre domaine d’étude se place principalement dans le cadre de l’échelle expérimentale de Mayr, qui permet par le biais de mesures cinétiques d’effectuer un classement des molécules par ordre de réactivité. Dans un premier temps, de grande avancées ont été réalisées durant cette thèse vis-à-vis de la prédiction théorique de l’électrophilie expérimentale des accepteurs de Michael. Puis dans un second temps, nous nous sommes intéressées à l’application des descripteurs de réactivité sur la liaison chimique, et particulièrement la liaison halogène. Enfin, une partie de synthèse réalisée au cours de cette thèse est présentée, en proposant une nouvelle voie de synthèse des cations iminium vinyloguesThe study of global, local and non-local reactivity descriptors of a reactive system is of paramount importance in order to understand the reactivity of all chemical processes during a reaction. The goal of this thesis was then to develop new reactivity descriptors, as well as prediction models based on them, in order to study chemical reactivity. The main theoretical methods used were the Conceptual Density Functional Theory (CDFT) and Quantum Theory of “Atoms in Molecules” (QTAIM), which are both based on electron density. Our field of study is mainly within the framework of the Mayr experimental scale, which allows, through kinetic measurements a classification of molecules in order of reactivity. In the first part, great advances were made during this thesis with respect to the theoretical prediction of experimental electrophilicity of Michael acceptors. Then in a second step, we looked at the application of reactivity descriptors on the chemical bond, and in particular the halogen bond. Finally, a part of synthesis carried out during the course of this thesis is presented, by proposing a new way of synthesis of vinylogous iminium cations
38
Williams, Sharlene Renee. "Influence of Electrostatic Interactions and Hydrogen Bonding on the Thermal and Mechanical Properties of Step-Growth Polymers." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/29397.
Full textAbstract:
Current research efforts have focused on the synthesis of novel, segmented, cross-linked networks and thermoplastics for emerging technologies. Tailoring macromolecular structures for improved mechanical performance can be accomplished through a variety of synthetic strategies using step-growth polymerization. The synthesis and characterization of novel Michael addition networks, ionene families, and ion-containing polyurethanes are described, with the underlying theme of fundamentally investigating the structure-property relationships of novel, segmented macromolecular architectures. In addition, it was discovered that both covalent and electrostatic crosslinking play an important role in the mechanical properties of all types of polymers described herein.
Novel cross-linked networks were synthesized using quantitative base-catalyzed Michael chemistry with acetoacetate and acrylate functionalities. These novel synthetic strategies offer unique thermo-mechanical performance due to the formation of a multiphase morphology. In order to fundamentally elucidate the factors that influence the kinetics of the Michael addition reaction a detailed analyses of model compounds were conducted in the presence of an in-situ IR spectrometer to optimize reaction conditions using statistical design of experiments. Networks were then prepared based on these optimized conditions. The mechanical performance was evaluated as a function of molecular weight between crosslink points. Furthermore, the incorporation of hydrogen bonding within the monomer structure enhanced mechanical performance. The changes in morphological, thermal, and mechanical properties evaluated using dynamic mechanical analysis (DMA) and tensile behavior are described. In addition, the use of preformed urethane segments provides a safer method for incorporating hydrogen bonding functional groups into macromolecules.
In order to compare the thermomechanical and morphological properties of ion-containing polyurethanes to non-charged polyurethanes, poly(tetramethylene oxide)-based polyurethanes containing either a novel phosphonium diol or 1,4-butanediol chain extenders were prepared using a prepolymer method. The novel phosphonium polyurethane was more crystalline, and it was presumed that hydrogen bonding in the non-charged polyurethane restricted polymer mobility, and reduced PTMO crystallinity, and hydrogen bonding interactions were significantly reduced due to the presence of phosphonium cations. These results correlated well with mechanical property analysis. The phase separation and ionic aggregation were demonstrated via wide-angle X-ray scattering, small-angle X-ray scattering, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy during STEM imaging, as described herein. In addition, a novel polyurethane containing imidazolium cations in the hard segment was synthesized and behaved very similarly to the phosphonium cation-containing polyurethane.
Ammonium ionenes, which contain quaternary nitrogen in the macromolecular repeating unit, have many potential uses in biomedical applications. They offer interesting coulombic properties, and the charge density is easily controlled through synthetic design. This property makes ionenes ideal polyelectrolyte models to investigate the influence of ionic aggregation on many physical properties. Ammonium ionenes were prepared via the Menshutkin reaction from 1,12-dibromododecane and 1,12-bis(N,N-dimethylamino)dodecane. The absolute molecular weights were determined for the first time using an on-line multi-angle laser light scattering (MALLS) in aqueous size exclusion chromatography (SEC). Tensile testing and DMA were used to establish structure-property relationships between molecular weight and mechanical properties for a series of 12,12-ammonium ionenes. Furthermore, degradation studies in the presence of base support the possibility for water-soluble coatings with excellent mechanical durability that are amenable to triggered depolymerization. A novel synthetic strategy was utilized to prepare chain extended 12,12-ammonium ionenes containing cinnamate functional groups. In the presence of UV light, the polymers chain extended, and the resulting ionenes possessed enhanced thermomechanical properties and increased molecular weight. In addition, the novel synthesis of imidazolium ionenes was demonstrated, and the charge density was tuned for appropriate applications using either low molecular weight segments or oligomeric precursors. The change in charge density had a profound role in imidazolium ionene thermal and mechanical behavior.Ph. D.
39
Dotson, Michael Edward. "Improvements in Pamam Dendrimer Synthesis." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin998323664.
Full text
40
Araujo, Yara Jaqueline Kerber. "Enzimas em biocatálise (esterificação de aminas, adição de Michael, clonagem e expressão de álcool desidrogenase)." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/75/75133/tde-30072013-090956/.
Full textAbstract:
As lipases têm um papel importante no desenvolvimento da biotecnologia e são empregadas na química orgânica como biocatalisadores com alta regio- quimio- e enantiosseletividade. Além de permitir sínteses mais sustentáveis e que estão em concordância com os princípios da Química Verde. A resolução enzimática de aminas racêmicas tem se mostrado uma maneira eficiente de obter aminas enantiomericamente puras, que podem ser empregadas na síntese assimétrica de fármacos e agroquímicos. Neste trabalho a resolução enzimática de 4 aminas primárias sendo elas 2-amino-heptano 1, 2-metil-cicloexil amina 3, 1-metil-3-fenilpropilamina 2, 1,2,3,4-tetra-hidro-1-naftilamina 4, foram estudadas obtendo-se resultados relevantes. Para a 2-amino-heptano 1 resultados semelhantes aos da literatura foram obtidos com uma redução de 2,4 vezes no tempo reacional quando a resolução cinética foi em hexano na presença de CAL-B e acetato de etila como acilante obteve-se uma conversão na (R)-N-(1-metil-hexil)acetamida 4 de 42% e um excesso enantiomérico de 88% (tempo = 7h). Observaram-se também os efeitos da concentração de lipase no meio reacional, da temperatura e de diferentes solventes frente a 11 lipases. Os primeiros estudos de resolução cinética enzimática com a 2-metilcicloexil-amina 3 são apresentados neste trabalho com conversões de até 98% porém sem excesso enantiomérico. Uma outra característica das lipases é a capacidade de catalisar reações diferentes da sua função natural (promiscuidade), o que permite que elas catalisem reações de adição de Michael, além de suas reações normais que são a hidrólise e esterificação. A adição de Michael catalisada por lipases entre as 4 aminas primárias já citadas e acrilonitrila foi estudada com e sem a influência da irradiação micro-ondas, demonstrando a maior estabilidade de lipases imobilizadas sob irradiação micro-ondas. Os adutos de Michael obtidos (3-[(1-metil-hexil)amino]propanonitrila 9, 3-[(1-metil-3-fenilpropil) amino]propanonitrila 10, 3-[(2-metil cicloexil)amino]propanonitrila 11 e 3-(1,2,3,4-tetra-hidronaftaleno-1-amino)propanonitrila 12) foram sintetizados pela primeira vez com a metodologia onde foi utilizada a água, acrilonitrila e irradiação micro-ondas e os adutos 9, 10 e 11 não são descritos na literatura. Outro viés do trabalho foi a clonagem e expressão da álcool desidrogenase de Bacillus subtilis que foi clonada, expressa e purificada com sucesso. O interesse em tal enzima deve-se a resultados obtidos na literatura onde a utilização de células íntegras de B. subtilis apresentou a redução de cetonas a álcoois com alta enantiosseletividade.Lipases present an important role in the development of biotechnology and are employed as biocatalysts in organic chemistry with high regio-, quimioand enantioselectivity. Besides allowing more sustainable syntheses that are consistent with the principles of Green Chemistry. The enzymatic resolution of amines has been shown to be an efficient way to obtain enantiomerically pure amines, which can be used in asymmetric synthesis of pharmaceuticals and agrochemicals. In this work the enzymatic resolution of 4 primary amines them being 2-amino-heptane textbf 1, 2-methyl-cyclohexyl amine 3, 1-methyl-3-phenylpropylamine 2 1.2 ,3,4-tetrahydro-1-naphthylamine 4 were studied by obtaining relevant results. For the 2-amino-heptane 1 promoted results similar to the literature and were obtained with a 2.4 times reduction of the reactional time when the kinetic resolution was in hexane in the presence of CAL-B and ethyl acetate as acylating obtained a conversion in (R)-N-(1-methyl-cyclohexyl) acetamide 4 by 42 % and an enantiomeric excess of 88 % (time = 7h). We studied the effects of the concentration of lipase in the reaction, temperature and solvent using 11 different lipases. The first studies of enzymatic kinetic resolution with 2-methyl-cyclohexyl- amine 3 are presented in this work with conversions up to 98% but without enantiomeric excess. The ability of lipases to catalyze reactions with different natural function (promiscuity) is an important property, which allows them to catalyze Michael addition reactions beyond their normal reactions, the hydrolysis and esterification. The Michael addition catalyzed by lipases between the four aforementioned primary amines and acrylonitrile was studied with and without the influence of microwave irradiation, demonstrating the greater stability of immobilized lipases under microwave irradiation. The Michael adducts obtained (3 - [(1-methylhexyl) amino] propanonitrile 9, 3 - [(1-methyl-3-phenylpropyl) amino] propanonitrile 10, 3 - [(2 - methyl cyclohexyl) amino] propanonitrile 11 and 3 - (1,2,3,4-tetrahydronaphthalene-1-amino) propanonitrile 12) were first synthesized with the method where water is used, acrylonitrile and microwave radiation, the adducts 9,10 and 11 are not described in the literature. Another investigation of this study was the cloning and expression of alcohol desidrogrenase of Bacillus subtilis which has been cloned, expressed and purified successfully. Interest in the enzyme due to results in the literature where the use of whole cells of B. subtilis showed the reduction of ketones with high enantioselectivity.
41
Sadiq, Abdul [Verfasser]. "Bifunctional organocatalysts containing primary amines for asymmetric Michael additions / Abdul Sadiq." Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2012. http://d-nb.info/1035208709/34.
Full text
42
Beynon, Christopher. "Asymmetric phase transfer catalysed Michael additions and their application in synthesis." Thesis, University of Nottingham, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.588066.
Full textAbstract:
This thesis describes an investigation into organocatalysed asymmetric Michael additions and their application in synthesis. It focuses primarily on phase transfer catalysed processes, however other modes of catalysis are briefly investigated. Firstly, β-ketoesters derived from 1-indanone and l-tetralone are examined as potential Michael donors. Their addition to methyl vinyl ketone is studied, with a view to producing members of the Gibberellin family. Secondly, the use of an achiral phenoxide "co-catalyst" in conjunction with a chiral quaternary ammonium salt, derived from cinchonidine, is found to produce an effective catalytic species. It is shown to promote the addition of benzophenone glycine imines to a range of Michael acceptors in excellent levels of enantiocontrol (>90% ee). The Michael adducts are then successfully converted to their corresponding 2,5-disubstituted pyrrolidine species, with high maintenance of stereocontrol. A potential application of this co-catalyst methodology is then described in studies towards the synthesis of kaitocephalin.
43
Mailhol, Damien. "Additions de Michael stéréosélectives pour la formation de centres quaternaires chiraux." Thesis, Aix-Marseille 3, 2011. http://www.theses.fr/2011AIX30052.
Full textAbstract:
Dans le contexte de la synthèse éco-compatible, la réactivité et le transfert de chiralité de sulfoximines dans quelques réactions domino ou consécutives diastéréosélectives ont été étudiés pour la synthèse de carbocycles et d’hétérocycles d’intérêt. L’emploi de béta-cétosulfoximines comme pronucléophiles dans des additions de Michael diastéréosélectives a aussi été étudié. Dans la plupart de ces cas, l’induction asymétrique de l’atome de soufre chiral s’est révélée faible. Dans un second temps, nous avons étudié l’addition de Michael énantiosélective des cyclobutanones activées sur les nitroalcènes par une approche organocatalytique. En utilisant un catalyseur bifonctionnel, les produits attendus présentant deux centres stéréogènes contigus dont un quaternaire, ont pu être obtenus avec de très bons rendements et d’excellentes diastéréo- et énantiosélectivités. Le potentiel synthétique de ces dérivés cyclobutaniques a pu être démontré, en particulier pour la synthèse de gamma-lactones optiquement activesIn the context of eco-compatible synthesis, reactivity and chirality transfer of sulfoximines in some domino or consecutive diastereoselective reactions have been studied for the synthesis of carbocycles and heterocycles of interest. The use of béta-ketosulfoximines as pronucleophiles in diastereoselective Michael additions has also been studied. In most of these cases, the asymmetric induction of chiral sulfur atom was low. Then, we investigated the enantioselective Michael addition of activated cyclobutanones onto nitroalkenes by an organocatalytic approach. The resulting adducts exhibit two contiguous chiral carbon atoms including an all-carbon quaternary stereocenter. They were obtained with very good yields and excellent diastereo-and enantioselectivities by using a bifunctional catalyst. The synthetic potential of these cyclobutane derivatives could be shown, especially for the synthesis of optically active gamma-lactones
44
Fedotova, Alena. "Amines aromatiques stériquement encombrées dans la réaction d'aza-Michael : effets de solvant et haute pression." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR056/document.
Full textAbstract:
Au cours de cette thèse, nous avons rapporté que la combinaison unique de l'hexafluoroisopropanol (HFIP), utilisé comme solvant, et des conditions hyperbares (10-15 kbar) permet une addition sans précédent de nucléophiles-1,4 pauvres, comme les amines aromatiques, sur des récepteurs Michael encombrés, sans promoteur externe. De plus, l'addition d'hétéro-Michael d'anilines fonctionnellement substituées sur des esters insaturés-α,β est définie par la différence d'acidité entre le solvant et l'amine. La réaction avec des anilines plus basiques se déroule facilement dans le méthanol. En revanche, les solvants protiques très polaires comme les alcools fluorés (HFIP et TFE) favorisent l'addition d'aza-Michael de nucléophiles plus faibles. Enfin, une méthode verte et sans catalyseur de construction de nouveaux dérivés d'acides aminés contenant des fragments d'adamantane et d'aziridine a été développée. Et il est prouvé que la réaction d'aza-Michael initie la formation de l’hétérocycleAlong this PhD work, we have reported that the unique combination of hexafluoroisopropanol (HFIP), employed as solvent, and hyperbaric conditions (10-15 kbar) allows unprecedented 1,4-addition of poor nucleophiles such as aromatic amines onto sluggish (cumbersome) Michael acceptors without any promoter nor work-up. Moreover, The hetero-Michael addition of functionally substituted anilines to α,β-unsaturated esters is significantly defined by the difference of acidity between the solvent and the amine. Reaction with more basic anilines proceeds smoothly in methanol. In contrast, very polar protic solvent such as fluorinated alcohols (HFIP and TFE) favor the aza-Michael addition of more weak nucleophiles. Finally, green and catalyst-free method of new amino acid derivatives construction containing adamantane and aziridine fragments was developed. And it is proved that aza-Michael reaction initiates the formation of heterocycle
45
Goudedranche, Sébastien. "Réactions domino organocatalysées énantiosélectives à partir de cétoamides." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4354.
Full textAbstract:
Au cours de ces travaux nous nous sommes intéressés au développement de nouvelles transformations énantiosélectives combinant les outils modernes de la synthèse organique que sont les « Multiples Bond-Forming Transformations » et l'organocatalyse afin de synthétiser des molécules d'intérêt structural et biologique. Dans ce contexte, nous avons d'abord mis au point deux nouvelles réactions domino initiées par une addition de Michael. La première, une cascade addition de Michael-acylation, permet la synthèse de spiroglutarimides optiquement actifs à partir de β-cétoamides et de nouveaux bis-électrophiles, les cyanures d'acyle α,β-insaturés. La deuxième, une réaction domino addition de Michaelhémiacétalisation- hémiaminalisation, permet la synthèse de d'hétérocycles azotés à sept chaînons à partir d'α-cétoamides comme nouveaux bis-nucléophilesThis work focused on the development of novel enantioselective transformations combining Multiples Bond-Forming Transformations and organocatalysis which are modern tools of organic synthesis in order to synthetize molecules of structural and biological interests. In this context, we developed two new Michael addition initiated domino reactions. The first one, a domino Michael addition-acylation, allows the synthesis of optically active spiroglutarimides starting from β-ketoamides and α,β-unsaturated acyles cyanides as new biselectrophiles.The second one, a domino Michael addition-hemiaminalizationhemiacetalization, allows the synthesis of seven-membered aza-cycles using α-ketoamides as new bis-nucleophiles
46
Beck, Daniel Antony Speedie, and beckautomatic@gmail com. "Stereoselective intramolecular Michael addition reactions of pyrrole and their application to natural product syntheses." The Australian National University. Research School of Chemistry, 2006. http://thesis.anu.edu.au./public/adt-ANU20070130.130009.
Full textAbstract:
Chapter one; (-)-Rhazinilam and (-)-Rhazinal: Alkaloids with Anti-mitotic Properties Derived from Kopsia teoi, provides the background information behind the motives that initiated this research project. The plant alkaloid (-)-rhazinilam [(-)-1] and its naturally-occurring derivative (-)-rhazinal [(-)-13] both exhibit potent anti-mitotic activities and, as such, are interesting targets for total synthesis. Chapter one is a review of the literature regarding these two compounds and discusses the occurrence, proposed biosynthetic origins, structural elucidation and biological activites of compound (-)-1 and that of its analogues including alkaloid (-)-13. Previous total syntheses of these two compounds are then examined, concluding with the only reported total synthesis of compound (-)-13. Developed within the Banwell research group, this total synthesis produced the racemic modification of alkaloid (-)-13 due to a lack of any stereocontrol in the key intramolecular Michael addition step. This unprecedented key step, involving cyclisation of the C2 of pyrrole onto an N-tethered and ?,?-disubstituted acrylate to produce a quaternary-carbon stereogenic centre, would be of greatly enhanced utility if it could be achieved in a catalytic-enantioselective fashion. The realisation of this goal is the central aim of the research conducted within this thesis.
¶
Chapter two; Investigating Asymmetric Induction in the Intramolecular Michael Addition of pyrrole to N-Tethered Acrylates and Related Species, introduces the model study used to direct research towards achieving the goal of asymmetric induction in the title process. The model is a somewhat simplified version of the original process used in the total synthesis of compound (-)-13 involving cyclisation of the C2 of pyrrole onto an N-tethered and ?-monosubstituted Michael acceptor, to produce a tertiary-carbon stereogenic centre. This simplification allows the rapid synthesis of a broad range of potential substrates for use in the title process, thus enabling the investigation of various different approaches to inducing asymmetry therein. High levels of asymmetric induction are observed with the use of chiral substrates or catalysts, facilitating the synthesis of both 6- and 7-membered rings annulated to pyrrole with construction of the relevant tertiary-carbon stereogenic centre in enantio-enriched form. For the reactions producing a 6-membered ring annulated to pyrrole, unambiguous proof of the absolute sense of asymmetric induction observed in the intramolecular Michael addition event is established using a chemical correlation study involving elaboration of a key indolizine-type cyclisation product, to the plant alkaloid of known absolute stereochemistry, (-)-tashiromine [(-)-75]. For the reaction producing a 7-membered ring annulated to pyrrole, the same information is obtained via X-ray crystallographic analyses of a dibrominated derivative of a key pyrroloazepine-type cyclisation product.
¶
Chapter three An Enantioselective Total Synthesis of the Alkaloid (-)-Rhazinal: An Anti-mitotic Agent Isolated from Kopsia teoi., focuses on the application of methodology developed in the previous chapter, to the original goal of inducing asymmetry in the intramolecular Michael addition reaction, involving cyclisation of the C2 of pyrrole onto an N-tethered and ?,?-disubstituted acrylate to produce a quaternary-carbon stereogenic centre. This is ultimately achieved in a catalytic-enantioselective fashion, resulting in the first such total synthesis of the anti-mitotic alkaloid (-)-rhazinal [(-)-13].
¶
Chapter four Extending the Reaction Manifold to the Syntheses of Related Natural Products: A Formal Total Synthesis of (+)-Aspidospermidine and Syntheses of (-)-Rhazinilam and (-)-Leuconolam from (-)-Rhazinal, describes three extensions to the reaction manifold used in the enantioselective total synthesis of alkaloid (-)-13:
The acquisition in an enantioselective manner, of an intermediate previously obtained in racemic form, en route to the racemic modification of the natural product (±)-aspidospermidine [(±)-134], constitutes a formal and enantioselective total synthesis of (+)-aspidospermidine
[(+)-134].
The direct deformylation of (-)-rhazinal [(-)-13], is carried out, to produce the parent alkaloid
(-)-rhazinilam [(-)-1].
The pyrrole ring present in (-)-rhazinilam [(-)-1] is oxidised, to produce the related natural product (-)-Leuconolam [(-)-12] which has not, hitherto, been prepared by total synthesis.
¶Chapter five contains the experimental procedures and characterisation data associated with compounds described in chapters two to four.
47
Beck, Daniel Antony Speedie. "Stereoselective intramolecular Michael addition reactions of pyrrole and their application to natural product syntheses /." View thesis entry in Australian Digital Theses Program, 2006. http://thesis.anu.edu.au/public/adt-ANU20070130.130009/index.html.
Full text
48
Figueira, Flávio Alberto da Silva. "Expanded porphyrins and their evaluation as anion chemosensors." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13247.
Full textAbstract:
Doutoramento em QuímicaExpanded porphyrins are synthetic analogues of porphyrins, differing from the last ones and other naturally occurring tetrapyrrolic macrocycles by containing a larger central core, with a minimum of 17 atoms, while retaining the extended conjugation features that are a tremendous feature of these biological pigments. The core expansion results in various systems with novel spectral and electronic features, often uniques. Most of these systems can also coordinate cations and/or anions, and in some cases they can bind more than one of these species. In many cases, these molecules display structural features, such as non-planar structures, that have no antecedents in the chemistry of porphyrins or related macrocyclic compounds. This work will discuss several synthetic approaches for the synthesis of expanded porphyrins, namely the construction of new building blocks by Michael addition, as well as potential synthetic routes towards expanded porphyrins. The synthesis of smaller oligopyrrolic compounds namely, bipyrroles and dipyrromethanes, not only were developed for the synthesis of expanded porphyrins as they were also used in Knoevenagel condensations furnishing chromogenic compounds able to recognize different anions in solution. Also, an approach to the synthesis of novel expanded porphyrins namely sapphyrins has been done by aza-Michael additions. Several synthetic routes towards the synthesis of pyridyl and pyridinium N-Fused pentaphyrins and hexaphyrins have been explored in order to achieve compounds with potential applications in catalysis and PDI, respectively. Studies on the synthesis of compounds with potential anion binding properties, led to the structural characterization and NMR anion binding studies of [28]hexaphyrins functionalized with several diamines in the para position of their pentafluorophenyl groups. These compounds allow NH hydrogen bond interactions with various anions. All synthesized compounds were fully characterized by modern spectroscopic techniques.
Porfirinas expandidas são análogos sintéticos das porfirinas, diferindo destes apenas por possuírem um core contendo no mínimo 17 átomos. A expansão do core resulta em vários sistemas com novas características electrónicas e espectrais, e numa extraordinária química de coordenação. Em muitos casos é também possível interação supramolecular com um ou vários aniões. Outra característica interessante é a possibilidade destes macrociclos acomodarem mais do que um estado de oxidação variando as suas características de aromaticidade e planaridade sem antecedentes na química de macrociclos tetrapirrólicos e derivados. Este trabalho discute diversas rotas de síntese de macrociclos expandidos e sua derivatização, bem como a síntese de precursores bipirrólicos sobejamente conhecidos pela sua utilização como precursores na síntese de Porfirinas expandidas. Para este fim, unidades do tipo bipirrolico foram funcionalizadas através de adições de Michael. Estes pequenos compostos foram também derivatizados através de condensações de Knoevenagel para aplicação em coordenação de aniões demonstrando reconhecimento de diferentes aniões mediante uma variação de cor específica. No seguimento destes estudos de reactividade por Diels-Alder e/ou adições de Michael obtiveram-se novos derivativos do tipo safirina com substituições no interior do macrociclo. Tendo em vista a síntese de compostos com reconhecimento de aniões e potencial aplicação em PDT/PDI e catálise, macrocrociclos do tipo pentafirina e hexafirina foram derivatizados com diversos nucleófilos. Neste último, a introdução de grupos amino na sua periferia conduziu a um aumento drástico da capacidade de interação com aniões em solventes polares. Estudos de RMN com os compostos capazes de reconhecer aniões possibilitou a sua total caracterização estrutural demonstrando estruturalmente os grupos que participam no reconhecimento de aniões. Todos os compostos presentes sintetizados foram caracterizados estruturalmente com recurso a diversas técnicas espectroscópicas, nomeadamente: à ressonância magnética nuclear de protão, carbono 13 e de flúor 19, à absorção no Ultravioleta-Visível, à espectrometria de massa e sempre que possível a análise de raio-X de monocristal.
49
Lewandowska, Urszula. "Spontaneous small molecule migration via reversible Michael reactions." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/10635.
Full textAbstract:
Small molecule walkers developed to date take advantage of the reversibility of dynamic covalent bond formation to transport molecular fragments along molecular tracks using both diffusion processes and ratchet mechanisms. However, external intervention (the addition of chemical reagents and/or irradiation with light) is required to mediate each step taken by the walker unit in systems reported so far. In this Thesis, the first synthetic small molecule able to walk back-and-forth upon an oligoethylenimine track without external intervention via intramolecular Michael and retro- Michael reactions is described. The 1D random walk is highly processive and exchange takes place between adjacent amine groups in a stepwise fashion. The walker is used to perform a simple task: quenching of the fluorescence of an anthracene group situated at one end of the track as a result of the walking progress. In the presence of excess of base, the molecule preferentially ‘walks’ towards the favoured final foothold of tracks of increasing length and it is possible to monitor the population of all or a few positional isomers over time. In each case the molar fraction of walkers reaching the final foothold is determined quantitatively by 1H NMR. Control over the rate of exchange is achieved by varying the amount of base added. The dynamic migration of a small molecule upon the track is a diffusion process limited to one dimension and as such can in principle be described using the one dimensional random walk. Chapter I identifies a set of fundamental walker characteristics and includes an overview of the DNA-based and small molecule transporting systems published to date. Chapter II describes the inspiration for this work and model studies which lay the groundwork for the research presented in this thesis. The initial track architecture and optimisation of reaction conditions are demonstrated using a simple model compound which then led to the development and a detailed investigation of a first synthetic small molecule able to walk upon an oligoethylenimine track without external intervention. Chapter III presents a modified synthetic route towards the desired walker-track architectures and a comprehensive investigation of the dynamic properties of a series of tracks of increasing length upon which the walker migrates in a unidirectional fashion. The Outlook contains closing remarks about the scope and significance of the presented work as well as ideas for the design of novel small-molecule walkers, some of which are well under way in the laboratory. Chapter II (with the exception of model studies included at the beginning of the chapter) is presented in the form of article that has recently been published. No attempt has been made to re-write this work out of context other than merging content of the article with the supplementary information published together with the article. Chapter II is reproduced in the Appendix in its published format.
50
di, Iorio Nicola. "Regio- e stereocontrollo nell'addizione viniloga di alchilidenossindoli a nitrostireni via organocatalisi." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/6000/.
Full textAbstract:
The topic of this work is the simultaneous activation, promoted by 9-epi-NH2-DHQA-TU, of alkylideneoxindole and nistirene derivatives, respectively via base catalysis and hydrogen-bond catalysis. The chosen substrates, of high biological interest, are used as starting materials for a vinylogous Michael addition where we wish to control the stereochemistry of the two asymmetric carbons far away from the active site, respectively in γ and δ position. Due to the particular structure of the starting oxindoles, it is hereby presented the first variant of this reaction performed at its highest level of stereochemical complexity. It is possible as a matter of fact, to generate 24 isomers of the product. Specifically, given that the nucleophilic attack can occur from various, non equivalent regions of the starting molecule, our main goal was to achieve a complete regio- and stereocontrol of the reaction. We have verified that the reported organocatalyzed vinylogous reaction represents a valid integration of the metal-catalyzed one, since it affords highly stereochemically complex products in good to high yields and excellent optical purity.