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Tesi sul tema "Cyclopropane"

Autore: Grafiati
Pubblicato: 4 giugno 2021
Ultima modifica: 7 luglio 2024

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1

Watson, Hayley. "Synthesis and reactivity of cyclopropanes and cyclopropenes". Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/9032.

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Activated cyclopropanes have been extensively used in synthetic chemistry as precursors for cycloaddition reactions. The rationale behind this is their ability to undergo ring-opening when activated by a Lewis acid, this can be enhanced further by the presence of a carbocation stabilising group like electron-rich aromatics. The stabilised dipole formed after ring opening can be trapped with suitable electrophiles such as imines and aldehydes via a [3+2] cycloaddition reaction. This results in the synthesis of pyrrolidines and tetrahydrofurans in excellent yields but moderate diastereoselectivity. Similarly, 6-membered heterocycles can be formed via a [3+3] cycloaddition reaction of activated cyclopropanes with nitrones. Now to extend the scope of the methodology, a [3+3] dipolar cycloaddition has been developed using activated 2,3 disubstituted cyclopropane diesters to access a range of highly functionalised oxazines in moderate to good yields (50-75%) and with reasonable diastereoselectivity. The use of activated symmetrical disubstituted cyclopropanes afforded the desired oxazines in a regio- and diastereocontrolled manner, while the use of unsymmetrical cyclopropanes significantly reduced the diastereoselectivity of the reaction. The stereochemistry outcome of the reaction developed was determined by nOe analyses and X-ray diffraction structures could be recorded in some examples. A new methodology has also been developed to gain access to novel N-heterocyclic- and phenol- substituted cyclopropanes in one step from the corresponding cyclopropene via a conjugated addition.
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2

Huber, Florian Anton Martin. "Stereocontrolled cyclopropane synthesis". Thesis, Bangor University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297672.

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3

Pedersen, Daniel Sejer. "Asymmetric cyclopropane synthesis". Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613762.

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4

Licence, Peter. "Synthetic studies in cyclopropane chemistry". Thesis, Bangor University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364988.

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5

Thomas, Stephen Patrick. "Phosphorus mediated asymmetric cyclopropane synthesis". Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613118.

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6

Glen, Anthony D. "Synthetic studies on cyclopropane fatty acids". Thesis, University of Newcastle Upon Tyne, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386040.

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7

Phun, Lien Hoang. "Innovative approaches to carbocyclic and heterocyclic compounds using strained carbocycles". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47542.

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Natural products and small molecules play a major role in drug development. However, using natural products as a source of medicine comes with many challenges, such as lack of natural abundance and difficulty in isolation. Consequently, synthetic organic chemistry is a solution in order to access these compounds in usable quantities. However, synthetic chemisty comes with its own challenges such as efficiency, chemoselectivity, stereoselectivity and enantioselectivity. Therefore, synthetic tools that addresses these challenges are required solve these limitations. This thesis discusses new methodologies using strained carbocycles (cyclopropanes and cyclopropenes) as the reactive subunit for the construction of different carbocyclic and heterocyclic compounds. The homo-Nazarov cyclization of alkenyl and heteroaryl cyclopropyl ketones was used in order to construct cyclohexenones, cyclohexenols, heteroaryl ring-fused cyclohexenones, dihydrofurans, furans and furanones in a mild and efficient manner. Benzofused heteroaromatic compounds were achieved via the Lewis acid-catalyzed cycloisomerization of cyclopropene-3,3-dicarbonyls and furan-3-carboxylates. These heteroaromatic compounds can be applied to medicinal chemistry and material science.
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8

Walther, Stefan. "Cyclopropane als Edukte zur Synthese von Calicenen /". [S.l : s.n.], 1985. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.

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9

Tarwade, Vinod. "Directed carbozincation reactions of cyclopropene derivatives". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 210 p, 2010. http://proquest.umi.com/pqdweb?did=1993336541&sid=7&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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10

Yan, Ni. "Stereoselective carbometallation reactions of cyclopropenes". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 207 p, 2008. http://proquest.umi.com/pqdweb?did=1456289621&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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11

Jevric, Martyn. "Synthesis of 1,2-Dihydronaphtho[2,1-b]furans. Reactions of 1,2-Dioxines and stabilised phosphorus ylides /". Title page, Index and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phj589.pdf.

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12

Afshari, Mohammad. "Quelques aspects de la réactivité ambiphile de carbocycles à trois chaînons". Aix-Marseille 3, 1992. http://www.theses.fr/1992AIX30044.

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Ce travail est consacre a l'etude des deux aspects de la reactivite ambiphile de la structure cyclopropanique. La premiere partie porte sur le comportement electrophile d'acylcyclopropanes qui ont ete opposes a l'allyltrimethylsilane en presence d'acide de lewis. Cette etude nous a permis de mettre en evidence un aspect nouveau de la reactivite du cyclopropane monoactive. L'identification des produits nous a fait postule l'intervention d'un intermediaire cyclopropylcarbinyle forme apres l'addition d'une premiere molecule d'allylsilane sur le carbonyle. Suivant la structure de l'acylcyclopropane, cet intermediaire reagit soit par addition bimoleculaire d'une deuxieme molecule d'allylsilane sur le carbocycle, soit par attaque direct sur le carbone porteur de la charge positive formelle. Dans une deuxieme partie, pour etudier l'aspect nucleophile de la reactivite du microcycle, tout en conservant l'homogeneite du modele, nous avons synthetise des silylmethylenecyclopropanes. Le reactif nucleophile ambident genere a partir de ces composes par reaction avec l'ion fluorure (tbaf) a ete oppose a des aldehydes. Les produits obtenus consistent en un melange d'alcools a structure methylenecyclopropanique et cyclopropenique. L'ensemble de ces resultats peut d'interpreter par l'intervention partielle d'un anion silicate pentacoordine
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13

Hanlon, David James. "u-vinylidene and n-1-cyclopropenyliron complexes : chemistry and synthesis via 1, 1-dichlorocyclopropanes /". Full-text version available from OU Domain via ProQuest Digital Dissertations, 1985.

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14

Avery, Thomas Daniel. "New methodologies involving 1,2-dioxines and stabilised phosphorus ylides for diastereoselective and enantioselective cyclopropanation : a thesis submitted towards the degree of Doctor of Philosophy". Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09pha955.pdf.

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Copies of the author's previously published works inserted. Includes bibliographical references (leaves 170-176). Two novel methods for the synthesis of di- and tri-substituted diastereomerically-pure and enantiomerically enriched cyclopropanes have been developed and are discussed. Outlines preliminary procedures exploiting the two cyclopropyl manifolds, allowing for the preparation of closely related cyclopropyl di-acids
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15

Coxon, Geoffrey David. "The synthesis and chirality of cyclopropane fatty acids". Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285742.

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16

Pietruszka, Jörg. "Enantiomerenreine Cyclopropane : neue Bausteine für die Natur- und Wirkstoffsynthese /". Herdecke : GCA-Verl, 2001. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=009621579&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.

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17

Poitou, Frédéric. "Résolution enzymatique de cyclopropylcarbinols : application à la séparation des isomères de l'alcool chrysanthémique". Aix-Marseille 3, 1992. http://www.theses.fr/1992AIX30014.

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Cette etude se situe dans le contexte de l'application des reactions enzymatiques au dedoublement de cyclopropylcarbinols, par reactions d'esterification et de transesterification catalysees par deux lipases commerciales, la lipase pancreatique de porc (ec 3. 1. 1. 3) et la lipase de candida cyclindracea (ec 3. 1. 1. 3). Ce travail presentera successivement: la synthese chimique des produits de depart; la determination des configurations absolues et des exces enantiomeriques; la synthese asymetrique de quelques composes modele, gemdihalogenocyclopropyl, monohalogenocyclopropyl et cyclopropylcarbinols; l'application des resultats obtenus et des strategies mises au point a la separation des enantiomeres et stereoisomeres du chrysanthemol
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18

NEVELLEC, LAURENCE. "Synthese d'analogues de nucleosides cyclobutaniques et cyclopropaniques". Le Mans, 1995. http://www.theses.fr/1995LEMA1018.

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Ce travail est axe sur la synthese d'analogues de nucleosides cyclobutaniques et cyclopropaniques a visee antivirale, par differentes voies d'introduction directe de la base purique ou pyrimidique sur des carbocycles fonctionnalises. Des composes cyclobuteniques ont ete synthetises a partir de l'anhydride cis-4-cyclobut-3-ene-1,2-dicarboxylique, obtenu par la reaction photochimique entre l'acetylene et l'anhydride maleique. L'ouverture nucleophile d'epoxydes cyclobutaniques en derivant a ainsi conduit a la synthese d'analogues de nucleosides cyclobutaniques trihydroxyles. La contraction de cycle c4-c3 stereoselective d'un -bromocyclobutanol en milieu basique a permis d'acceder a un aldehyde cyclopropanique, precurseur d'un analogue de nucleoside cyclopropanique-1,2,3 trisubstitue possedant un groupe methylene entre la base et le carbocycle. Cette approche constitue une voie originale dans la synthese d'analogues de nucleosides cyclopropaniques. L'introduction directe de l'adenine s'est egalement operee par substitution nucleophile d'un mesylate cyclobutanique. Seul le mesylate de stereochimie cis a conduit a la synthese d'un analogue de nucleoside cyclobutanique dihydroxyle. Dans des conditions de reaction de couplage identiques, le mesylate de stereochimie trans, a conduit a une regression de cycle dont certains aspects mecanistiques ont ete determines par deuteriation du mesylate en deux positions. Tous ces travaux ont necessite une etude approfondie en rmn: la mesure d'effets noe a permis la determination de la stereoselectivite des reactions, notamment lors de l'addition de phsecl sur differents cyclobutenes. L'identification de la regiochimie des attaques nucleophiles de la base heterocyclique a ete effectuee grace a diverses sequences en rmn
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19

Bouchtalla, Sahib. "Etude thermodynamique des clathrates hydratés d'hydrocarbures légers par mesure de tension de vapeur d'eau". Dijon, 1986. http://www.theses.fr/1986DIJOS039.

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20

Terki-Hassaïne, Mounir. "Étude à haute résolution du cyclopropane par spectroscopie Raman stimulé". Dijon, 1987. http://www.theses.fr/1987DIJOS046.

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La technique de jet moléculaire a été utilisée pour clarifier le spectre et simplifier les attributions rotationnelles. Néanmoins, a partir des données Raman, seules les simulations des contours des bandes 2v2 et v1 ont pu être obtenues en raison de la complexité du spectre due aux interactions rovibrationnelles multiples dans la région spectrale étudiée
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21

Podder, Ranjan Kumar. "Formation and cleavage of cyclopropane ring systems and related studies". Thesis, University of North Bengal, 1986. http://hdl.handle.net/123456789/848.

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22

Gillman, Kevin W. "Hydroboration of strained cyclopropane ring systems promoted by Wilkinson's catalyst /". Online version of thesis, 1991. http://hdl.handle.net/1850/10947.

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23

James, Rachel Anne. "Nucleophilic substitution reactions of (alkoxymethylene) dimethylammonium chloride and cyclopropane methodology". Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342180.

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24

Ner, S. K. "The synthesis and testing of cyclopropane inhibitors of Carboxypeptidase A". Thesis, University of Strathclyde, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381719.

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25

Terki, Hassaïne Mounir. "Etude à haute résolution du cyclopropane par spectroscopie Raman stimulé". Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376102709.

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26

Johnson, William T. G. "Synthesis of precursors of a highly pyramidalized alkene and ab initio calculations on methylenecyclopropane, cyclopropene, and 1,3-diradicals /". Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/11586.

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27

Willis, Terrance James 1959. "THERMAL RING OPENING OF CYCLOPROPANES AS INITIATORS FOR POLYMERIZATION". Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276540.

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Donor-Acceptor tetramethylenes have been studied by polymerizations. 1,4-Zwitterionic intermediates are indicated when reactive tetramethylenes initiate homopolymerization. Alternately, 1,4-diradical intermediates initiate copolymerization. This basis for studying intermediates has led to an empirical table for predicting the zwitterionic and diradical nature of addition and polymerization reactions of tetramethylenes. Here we attempted to extend this work to trimethalylenes by studying the thermal ring opening of ethyl chrysanthemate, ethyl 1-cyano-2-(4-methoxyphenyl)-cyclopropane-corboxylate, ethyl 1-cyano-2-(2-methoxyphenyl)-cyclopro-panecroboxylate, and diethyl 1,3-dicyano-w,r-di(2-methoxyphenyl)-cyclobutanedicarboxylate. These compounds were found to be thermally stable to 150°C and did not initiate polymerization in styrene, methyl methacrylate, a series of high boiling acrylates, and dimethyl fumarate. Free radicals were trapped in dimethyl fumarate to give oligomers at temperatures above 110°C. Even though the compounds studied did not initiate polymerization at decomposition temperatures of 175°-200°C, dimethyl fumarate may prove useful in these studies in the future.
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28

Carné-Carnavalet, Benoît de. "Synthèse de cyclopropanes substitués par des couplages catalysés au palladium". Paris 6, 2012. http://www.theses.fr/2012PA066650.

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Les cyclopropanes sont rencontrés dans de nombreux produits naturels ou synthétiques bioactifs. Les travaux réalisés portent sur le développement de couplages catalysés par le palladium permettant d’accéder à des cyclopropanes diversement substitués. Des couplages de Suzuki-Miyaura impliquant les cis- et trans-2-benzyloxy-cyclopropyltrifluoroborates de potassium ont pu être mis au point après un important travail d’optimisation. L’accès à des aminocyclopropanes par des couplages de type Hartwig Buchwald impliquant des iodures cyclopropaniques s’est révélé beaucoup plus difficile à mettre en œuvre. Leur faisabilité a été démontrée avec un exemple, en version intramoléculaire, mais les résultats n’ont pas pu être généralisés. Les premiers exemples de couplages de Sonogashira entre des iodures cyclopropaniques diversement substitués et des alcynes terminaux ont été décrits. Les alcynylcyclopropanes correspondants sont obtenus avec d’excellents rendements et rétention de configuration. Les cis-2-alcynylcyclopropanecarboxamides préparés par cette méthode peuvent subir une cyclisation 5 exo-dig en milieu basique et conduire à des énamides incorporant un motif 3-azabicyclo[3. 1. 0]hexane. En milieu acide, ces composés engendrent des ions N-acyliminiums bicycliques pouvant être impliqués dans des réductions ioniques ou des cyclisations de Pictet-Spengler menant à une grande diversité de composés hétérocycliques azotés originaux de manière totalement diastéréosélective
Cyclopropanes are encountered in several natural and synthetic products displaying a wide range of biological activities. The goal of our studies has been the development of palladium-catalyzed cross coupling reactions allowing access to diversely substituted and functionalized cyclopropanes. Suzuki-Miyaura cross-couplings involving potassium cis- and trans-2-benzyloxy-cyclopropyltrifluoroborates have been successfully developed after an important optimization work. The synthesis of aminocyclopropanes by Hartwig-Buchwald cross-couplings involving cyclopropyl iodides turned out to be more difficult to achieve. The feasibility of such couplings was demonstrated with an example, dealing with an intramolecular reaction, but the results could not be generalized. The first examples of Sonogashira cross-couplings of diversely substituted cyclopropyl iodides with terminal alkynes have been described. The corresponding alkynylcyclopropanes were obtained with excellent yields and with retention of configuration. The cis-2-alkynylcyclopropanecarboxamides prepared by this strategy can be subsequently involved in a 5 exo dig cyclization under basic conditions to provide enamides incorporating a 3 azabicyclo[3. 1. 0]hexane moiety. Under acid conditions, these compounds generate bicyclic N-acyliminium ions that can be involved in ionic reductions or Pictet-Spengler cyclizations to provide a wide variety of structurally complex heterocyclic compounds with complete diastereoselectivity
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29

Oudeyer, Sylvain. "Nouveaux procédés d'électrosynthèse et de synthèse de cyclopropanes, d'époxydes et d'aziridines". Paris 12, 2003. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990003949000204611&vid=upec.

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Le but de ce travail est la mise au point de nouvelles méthodes de réduction de polyhalogénométhanes activés permettant l’accès à des espèces nucléophiles hautement réactives qui conduiront à la formation de petits cycles par addition sur divers réactifs électrophiles. Nous avons mis au point un procédé d’électrolyse catalysée par un système fer/cuivre ainsi qu’un procédé chimique, de type Barbier, impliquant du magnésium en milieu DMF. La synthèse de cyclopropanes, d’époxydes et d’aziridines a été réalisée à partir respectivement de cétones ou d’esters alpha, beta-éthyléniques, d’aldéhydes ou de cétones non conjugués, et d’imines. En fonction des réactifs utilisés, ces deux méthodes se sont avérées complémentaires et souvent plus simples, plus efficaces et moins polluantes que les voies de synthèse décrites dans la littérature. Par ouverture en milieu acide, les 2-acyl-1,1- diphénylcyclopropanes conduisent soit à des beta-benzhydryl-alpha, beta-cycloalcénones soit à des naphtalènes polysubstitués
The aim of this work is to develop new synthetic methods for preparation of reactive nucleophilic species by activation of polyhalomethyl compounds. The latter species would react with various electrophilic compounds to produce small rings. An electrochemical process involving an iron/copper complex catalytic system and a simple Barbier reaction involving magnesium in DMF were used to prepare cyclopropanes, oxiranes and aziridines from respectively alpha, beta-unsaturated ketones or esters, nonconjugated aldehydes or ketones, and imines. These two simple and complementaiy new processes provide good yields in small rings, and moreover, they must be regarded as interesting alternatives to most common syntheses which use pollutant compounds or require very complex procedures. The 2-acyl-1,1-diphenylcyclopropanes thus obtained lead, through acid-catalysed ring-opening, to either substituted naphtalenes or beta-benzhydryl-alpha, beta-cycloalkenones
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30

Oudeyer, Sylvain Nedelec Jean-Yves. "Nouveaux procédés d'électrosynthèse et de synthèse de cyclopropanes, d'époxydes et d'aziridines". Créteil : Université de Paris-Val-de-Marne, 2007. http://doxa.scd.univ-paris12.fr:8080/theses-npd/th0394900.htm.

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31

Ernouf, Guillaume. "Réarrangements sigmatropiques - Synthèse de cyclopropanes fonctionnalisés". Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066719/document.

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Les cyclopropanes sont rencontrés dans de nombreux produits naturels ou synthétiques bioactifs. Les travaux exposés dans ce manuscrit portent sur le développement de réarrangements sigmatropiques [3,3] impliquant des dérivés de cyclopropénylcarbinols pour accéder à des alkylidènecyclopropanes fonctionnalisés, précurseurs de cyclopropanes diversement substitués. Le réarrangement des cyanates de cyclopropénylcarbinyle a permis d'obtenir des dérivés N-acylés d'alkylidène(aminocyclopropanes). Une méthode efficace et stéréosélective, impliquant le réarrangement d'Ireland-Claisen des glycolates et glycinates de cyclopropénylcarbinyle, a également été mise au point pour synthétiser des alkylidènecyclopropanes possédant un motif α-hydroxy ou α-amino acide. Le champ d'application de ce réarrangement a été étendu avec succès à des gem-difluorocyclopropènes. L'hydrogénation diastéréosélective des alkylidènecyclopropanes diversement substitués issus de ces rérrangements sigmatropiques a ensuite permis d'obtenir des cyclopropanes fonctionnalisés
The cyclopropane ring is ubiquitous in natural and biologically active compounds. [3,3]-Sigmatropic rearrangements of cyclopropenylcarbinol derivatives have been developed to access functionalized alkylidenecyclopropanes, which are useful precursors of diversely substituted cyclopropanes. We have shown that the rearrangement of cyclopropenylcarbinyl cyanates could be accomplished under mild conditions to obtain N-acyl alkylidene(aminocyclopropanes). The Ireland–Claisen rearrangement of glycolates or glycinates derived from secondary cyclopropenylcarbinols has been developed as an efficient and stereoselective method for the synthesis of alkylidenecyclopropanes possessing an α-hydroxy or α-amino acid moiety. The scope of this transformation was successfully extended to gem-difluorocyclopropenes. The alkylidenecyclopropanes resulting from these latter sigmatropic rearrangements are valuable precursors of substituted cyclopropanes by diastereoselective hydrogenation of the exocyclic olefin
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32

Jerome, L. "The generation and reactivity of functionalised organozinc carbenoids for cyclopropane synthesis". Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/17481/.

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This thesis describes the generation and reactivity of functionalised organozinc carbenoids for cyclopropane synthesis with alkenes. In the introductory chapter, a brief overview of the different methods for preparation of heteroatom-functionalised cyclopropanes is presented, including [2+1] cycloaddition reactions using a carbene or carbenoid as a cyclopropanating agent with an alkene, ionic stepwise methods, and chemical modifications from existing cyclopropanes. The remainder of this chapter then focuses on previous work within our own group in this area. The second chapter presents the results obtained from different areas of research in the present study, the first of these being a deeper understanding and extension of the research work undertaken by my predecessor for the development of the cyclopropanation reaction using an “amidoorganozinc” carbenoid derived from N,N diethoxymethyloxazolidinones derivatives in the presence of a source of zinc and chlorotrimethylsilane. Thus, the chemoselectivity and stereoselectivtity of the reaction were fully studied, and a quadrant model was constructed to rationalise the stereochemistry of the products obtained. The second part of this section outlines the generation of new enantiopure organozinc carbenoids precursors derived from substituted chiral precursors followed by the synthesis of novel enantiopure highly functionalised N-cyclopropyl oxazolidinones. The intramolecular version of this cyclopropanation reaction was then successfully studied using diethoxylactam derivatives as organozinc carbenoid precursors. The methodology was then applied to the preparation of novel aminocyclopropyl functionalised compounds selected as interesting building blocks which can lead to the synthesis of natural and biologically active compounds. The fifth part of this chapter describes subsequent studies towards the design of new carbenoid precursors containing additional functional groups of interest. Finally, a brief study on the potential of an organozinc carbenoid to participate in a novel [2,3] sigmatropic rearrangement was investigated. The thesis concludes with a summary of the results obtained, a detailed description of the experimental procedures used and the characterization and analysis of the compounds prepared, together with a full bibliography.
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33

Courtois, Fabienne. "Etudes mécanistiques de la cyclopropane Fatty Acid synthase d' Escherichia coli". Paris 6, 2006. http://www.theses.fr/2006PA066017.

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34

Ross, Adam. "Novel routes to, and reactions of, cyclopropanes". Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/16315.

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An array of different cyclopropanes have been synthesised, including the structurally simple 1-phenylcyclopropanol. These were synthesised in yields upwards of 60%, using the well published Kulinkovich reaction. From 1-phenylcyclopropanol, variations of the cyclopropane core structure were synthesised, creating species ideal for palladium cross coupling reactions, such as 1-phenylcyclopropyl methanesulfonate and 1-phenylcyclopropyl 4-methylbenzenesulfonate. These were formed in 50 and 60% yield respectively. Once obtained these cyclopropanes were used to perform Suzuki cross coupling reactions towards the formation of 1,1- diphenyl cyclopropane. Unfortunately, despite various attempts, the palladium cross coupling reactions were unsuccessful. The work did facilitate the discovery of a novel methodology for the synthesis of tetra substituted alkenes. Using similar methodology as that developed for the formation of 1- phenylcyclopropanol, a McMurry reaction was able to be performed on a number of different ketones. This reaction formed a wide array of different tetra-substituted alkenes with yields ranging from 20-99%, depending on the nature of the starting material. The method, involving the use of 9 equivalents of Grignard reagent and stoichiometric amounts of titanium isopropoxide, is a unique way of making low valent titanium in situ, as well as being homogeneous. Methodology for the formation of vinyl cyclopropanes containing an amide moiety has been developed, allowing a variety of different amines to be coupled to two different cyclopropanes. Once these species were synthesised, a palladium catalysed cyclisation, Heck reaction, carbonylation cascade was developed. This allowed the core cyclic structure of the stemona alkaloids to be obtained in a single reaction vessel with good yields of up to 52% depending on the amine used. The cascade was then applied to a fully substituted cyclic natural product core. However, the cascade reaction was unsuccessful. Efforts to alter the structure of the starting material, to remove the potentially hindering bromine, provided no improvement. It was established that the tetrakis(triphenylphosphine) palladium (0) catalyst used was too encumbered for insertion in to the sterically hindered starting material, which is likely to be causing the failure of the reaction.
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35

Pallerla, Mahesh Kumar. "Strain as a design principle stereoselective Pauson-Khand reactions of cyclopropenes /". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 274 p, 2008. http://proquest.umi.com/pqdweb?did=1456289601&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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36

Le, Gall Lefas Marie. "Synthese et proprietes biologiques de derives beta-substitutes ou cyclopropaniques de ligands melatoninergiques". Paris 11, 1998. http://www.theses.fr/1998PA114850.

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37

Niger, Robert J. "Addition of arenesulfenyl chlorides to quadricyclene /". Online version of thesis, 1992. http://hdl.handle.net/1850/11153.

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38

Hillier, Michael Campion. "The intramolecular cyclopropanation reaction and its application towards the synthesis of pseudopeptides and natural products /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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39

Davidson, James Prentice. "Calorimetric and structural studies of 1,2,3-trisubstituted cyclopropanes as conformationally constrained peptide mimics /". Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3008309.

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40

Kikuchi, Kai. "Studies Towards the Total Synthesis of Avenaol". Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/25861.

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Plant hormones (phytohormones) control all aspects of plant growth and development. Strigolactones are a class of phytohormones that also trigger the germination of parasitic plants of the Orobanchaceae family. Avenaol was the first isolated non-canonical strigolactone and was found to contain an all-cis cyclopropane, a highly synthetically interesting structure. The total synthesis of avenaol in 2017 by Tsukano and co-workers was the first total synthesis of any non-canonical strigolactone. It was completed in 35 steps with an overall yield of 0.14%. As expected the all-cis cyclopropane presented the major challenge, being prepared in 19 steps and 6.2% yield. In this work, we outline the stereo-controlled synthesis of dihalocyclopropanes (chapter 2) and reactivity under both radical (chapter 3) and polar (chapter 4) conditions as promising intermediates en route to the core of avenaol. We have developed a route to an advanced intermediate in the synthesis of 7-epi-avenaol, an epimer which is believed to be produced by the same plant (A. strigosa) as avenaol.
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41

Grech, Jason Mark. "The synthetic applications of organomercurials arising by the cleavage of cyclopropane derivatives". Thesis, University of Leicester, 1996. http://hdl.handle.net/2381/33701.

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Organomercurial esters 2a-c obtained from cyclopropyl alcohols la-c in three or five (depending on whether the system is cis or trans) steps, react with organocuprates via an intramolecular addition across the carbonyl bond to generate the corresponding lactolate. Quenching of the latter intermediate with water leads to the lactol 3a, c in the cycloheptane and cyclopentane series, whereas the open hydroxyketone 4b is formed in the cyclohexane series. Quenching of the lactolate with BF3 Et2O gives different products, as demonstrated for the cyclohexane series. The Pd(II)-catalysed carbonylation of chloromercurio alcohols 5a-c allows the construction of either cis- or trans-fused lactone rings 6a-c. The stereochemistry of the lactone annulation is controlled by the Hg (II) reagent to initially open the cyclopropane ring, in conjunction with oithogonal protection.
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42

Roje, Marin. "Synthèse asymétrique de petits cycles : Epoxydes,aziridines et cyclopropanes". Université Louis Pasteur (Strasbourg) (1971-2008), 2003. https://publication-theses.unistra.fr/public/theses_doctorat/2003/ROJE_Marin_2003.pdf.

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Le travail décrit dans ce mémoire porte sur la synthèse asymétrique d'époxydes et d'aziridines énantiomériquement enrichis au départ d'ylure de soufre chiraux dérivé du (+)-(R,R,R)-oxathiane d'Eliel, aussi bien que la synthèse asymétrique de cyclopropanes par la cyclopropanation catalytique. Dans un premier temps l'ylure de benzyle sulfonium chiral, obtenu grâce à l'emploi de base phosphazène EtP2, a été mis en réaction avec des aldéhydes polyaromatiques afin de générer des époxydes diaromatiques avec des excès énantiomériques très élevé entre 94,6% et 98,7% et de configuration absolue (R,R). La configuration absolue de ces époxydes a été déterminé à partir des alcools correspondants (ouverture par LiAlH4) en utilisation la méthode de "CD-exciton-tweezer ". La configuration absolue est (1R,2R), en accord avec le modèle d'approche postulé auparavant. Dans un deuxième temps nous avons montré que cette méthode était applicable à la synthèse de N-tosyl aziridines 2,3-disubstituées de configuration absolue (2R,3R) avec d'excellents excès énantiomériques allant de 98,7 à 99,9 % et des temps de réaction inférieurs à 30 minutes. Nous avons montré que la configuration absolue est (2R,3R) pour les trans-aziridines et (2S,3R) pour les cis-aziridines en utilisant la méthode de Bijvoet dans l'analyse par des rayons X. Ces résultats sont en concordance avec notre modèle d'approche proposé. Nous avons également réalisé une étude comparative des ligands azotés de symétrie C1 afin d'améliorer la stéréosélectivité de la réaction de cyclopropanation catalytique en modifiant leur topologie chirale
The asymmetric synthesis of enantiomerically enriched epoxides and aziridines starting from chiral sulphur ylide derived from (+)-(R,R,R)-Eliel's oxathiane, as well as asymemetric synthesis of enantiomerically enriched cyclopropanes by asymmetric cyclopropanation is described in this present work. The reaction between the chiral benzyl sulfonium ylide, derived from Eliel's oxathiane by the use of phosphasene base EtP2, and polyaromatic aldehydes afforded disubstituted epoxides with high enantiomeric purity between 94,6 and 98,7% and with an absolute configuration (R,R). The absolute configuration of these epoxides has been determined by "CD-exiton-tweezer" method using corresponding alcohols (opening with LiAlH4) and it was found to be (1R,2R)-configuration in consistency with the model established earlier. We have shown that this method can be successfully applied in the asymmetric synthesis of 2,3-disubstituted N-tosyl aziridines with (2R,3R) absolute configuration and with excellent enantiomeric purities from 98,7 to 99,9 % in less than 30 minutes. We have also shown that the absolute configuration is (2R,3R) for trans-aziridines and (2S,3R) for cis-aziridines by applying the Bijvoet X-ray method. These results are consistent with our proposed model. We have also performed a comparative study of some C1 chiral nitrogen ligands with the use in catalytic cyclopropanation, trying to increase the stereoselectivity by modifying their chiral topology
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43

Chawner, Stephen John. "Divergent synthesis of cyclopropane-containing fragments and lead-like compounds for drug discovery". Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/56635.

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The cyclopropane ring is key to a large number of medicinally‑relevant compounds that possess a broad spectrum of biological activities. This thesis details the preparation of novel bifunctional cyclopropanes through a divergent functionalisation approach utilising two readily accessible cyclopropyl‑scaffolds. The cyclopropanes generated sampled new areas of chemical space whilst being suitable 3‑dimensional fragments and lead-like compounds for drug discovery. A novel CoII-catalysed cyclopropanation generates two diastereoisomeric bifunctional cyclopropyl-scaffolds from commercially available reagents in an excellent yield and can be conducted on multi-gram scales. Asymmetric cyclopropanation has been explored with max ee = 73%. Divergent functionalisation of the ester was explored, utilising hydrolysis, reduction and amidation reactions to create a variety of functionalised cyclopropyl sulfides. The sulfide synthetic handle was oxidised to give the corresponding sulfoxides or sulfone selectively. Sulfoxide–magnesium exchange was explored and the cyclopropyl-organometallic species generated was trapped with a variety of electrophiles to create a diverse range of cyclopropane-containing products. The cyclopropyl-organometallic species was also utilised in Negishi cross-coupling, proving to be a versatile method to attach an aromatic or heteroaromatic directly onto the cyclopropane ring.
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44

Badiani, Kamal. "Synthesis and evaluation of enzyme inhibitors based on amino- and cyclopropane carboxylic acids". Thesis, University of St Andrews, 1997. http://hdl.handle.net/10023/14052.

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The coenzyme B12-dependent enzyme, glutamate mutase (E. C. 5.4.99.1), catalyses the reversible carbon-skeleton rearrangement of (2S)-glutamic acid to (25.35)-3-methylaspartic acid. Glutamate mutase is the first enzyme on the mesaconate pathway. A variety of glutamate and 3-methylaspartate analogues (which also include isotopically labelled molecules), were synthesised as molecular probes of the enzyme. Synthesis of stereospecifically labelled 3-ethylaspartic acid: (2S,3S)-[3'-C2H3], and (2S,3S)-[C2H2C2H3]-ethylaspartic acids were constructed using appropriately labelled iodoethane. (2S,3S)-2-Bromo-3-methylsuccinic acid was synthesised via the diazotization of (2S,3S)-3-methylaspartic acid, in the presence of bromide ion. (2S)-Methylsuccinic acid was synthesised by the catalytic hydrogenation of (2S,3S)-2-bromo-3-methylsucdnic acid. Biological studies of the synthesised compounds (including the labelled isotopomers) displayed no activity against glutamate mutase. 3-Methylaspartate ammonia-lyase, the second enzyme in the mesaconate pathway, catalyses the deamination of (2S,3S)-3-methylaspartic acid to mesaconic acid. A range of 1-substituted cyclopropane 1,2-dicarboxylic acids were synthesised using short efficient routes and were found to be good to potent inhibitors of 3-methylaspartase. X-ray crystallographic studies have determined the absolute stereochemistry. The mode of action of the most potent inhibitor, (1S,2S)-1-methylcyclopropane 1,2-dicarboxylic acid (20 mumol dm-3), is consistent with it acting as a transition state analogue for the central substrate deamination reaction catalysed by the enzyme. beta-Amino acids are constituents of many biologically active peptides. A general procedure for the synthesis of alpha-substituted-beta-amino acids has been developed. The synthesis involves a Baylis-Hillman amine catalysed conversion of methyl acrylate, with an appropriate aldehyde, to give the alpha-(hydroxyalkyl) acrylate. Bromination and subsequent azide displacement furnishes the azido alkene, which is catalytically hydrogenated, to furnish the beta-amino ester.
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45

Nyadanu, Aude. "Nouvelles réactions multicomposants et ouverture de cycles contraints pour la synthèse d’hétérocycles". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX065/document.

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Les réactions multicomposants (MCR) constituent une réponse à deux grands défis rencontrés par la chimie pharmaceutique : la découverte de nouvelles molécules bioactives ainsi que leur production à moindre coût dans le respect de l’environnement. En effet, en combinant plusieurs réactifs de façon monotope, les MCR permettent de synthétiser une grande diversité de molécules complexes par des procédés simples et rapides, avec de bons rendements, et en limitant fortement les déchets de réaction. Dans le cadre de cette thèse, nous avons mis au point de nouvelles réactions multicomposants impliquant des isonitriles, composés à la réactivité exceptionnellement riche.Nous nous sommes d’abord intéressés à l’utilisation d’acides forts dans la réaction de Ugi. Les premiers essais ont été réalisés avec des acides sulfiniques, sulfoniques, phosphiniques et phosphoniques, sans succès. Mais grâce à l’introduction de l’acide nitrique comme composant acide dans la réaction de Ugi, nous avons décrit une synthèse monotope de nitramines hautement fonctionnalisées à partir d’un aldéhyde, un isonitrile et un nitrate d’ammonium. Nous avons ainsi développé la première réaction multicomposant conduisant à la formation d’une liaison N-N.Nous avons également proposé une nouvelle variante de la réaction de Passerini impliquant des dérivés thiocarbonylés. Ces derniers étant généralement peu stables, nous avons mis au point une stratégie pour générer un thiocarbénium in situ à partir d’un 3-sulfanyl phthalide, en présence de tétrachlorure de titane. Le couplage de ce thiocarbénium avec un isonitrile et un acide carboxylique a conduit à la synthèse divergente de deux types d’hétérocycles soufrés : les thiophthalides et les 3-amino-4-sulfanyl isocoumarines. Cette étude constitue la première approche formelle de la réaction de Thio-Passerini.Enfin, dans la continuité de notre intérêt pour les dérivés soufrés, nous avons décrit une nouvelle synthèse de thiovinyléthers. Ces composés, synthétiquement équivalents à des dérivés thiocarbonylés, ont été obtenus par l’ouverture palladocatalysée de thiocyclopropanes. Si le recours à des métaux de transition pour l’ouverture de cycles contraints est bien connue pour des dérivés oxygénés ou azotés, il s’agit de la première réaction de ce type pour des dérivés soufrés.Ainsi, trois méthodologies originales ont été développées. Elles donnent accès à différents types de composés fonctionnalisés, potentiellement utiles en pharmacie et en agrochimie. Ces travaux s’appuient fortement sur la réactivité unique des isonitriles et viennent compléter cette chimie particulièrement riche
Multicomponent reactions (MCR) are a response to two big challenges faced by pharmaceutical chemistry : the discovery of new bioactive molecules and their production with reduced costs in a environmentally acceptable way. Indeed, by combining several reactants in one pot, MCR allow the synthesis of a wide diversity of complex molecules by simple and quick procedures, with good yields, and with limited amounts of reaction waste. In the framework of this thesis, we have developed new isocyanide-based multicomponent reactions, these compounds having an exceptionnaly rich reactivity.First, we were interested in the use of strong acids in the Ugi reaction. The first trials were made with sulfinic, sulfonic, phosphinic and phosphonic acids, and they failed. Nevertheless, thanks to the introduction of nitric acid as the acid component in the Ugi reaction, we described a one-pot synthesis of highly functionalized nitramines starting from an aldehyde, an isocyanide and an ammonium nitrate. This transformation is the first multicomponent reaction leading to a N-N bond formation.We also proposed a new variant for the Passerini reaction, involving thiocarbonyl derivatives. These compounds generally being quite unstable, we imagined a strategy in order to generate a thiocarbenium in situ from a 3-sulfanyl phthtalide, in the presence of titanium chloride. The coupling of this thiocarbenium with an isocyanide and a carboxylic acid leads to a divergent synthesis of two types of sulfur-containing heterocycles : thiophthalides and 3-amino-4-sulfanyl isocoumarines. This study represents the first formal approach of a Thio-Passerini reaction.Finally, as part of our continuing interest in in sulfur-containing derivatives, we described a new synthesis of thiovinylethers. These compounds, synthetically equivalent to thiocarbonyl derivatives, were obtained by the palladium-catalyzed ring opening of thiocyclopropanes.While the use of transition metals for constrained ring opening is well known for oxygen or nitrogen derivatives, this is the first reaction of this type for sulfur derivatives.Overall, we developed three original methodologies that give access to different types of functionalized compounds, potentially useful in pharmacy and agrochemistry. This work relies on the unique reactivity of isocyanides and adds on this especially rich chemistry
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46

Milanole, Gaëlle. "Les cyclopropanes monofluorés : nouvelle architecture pour la conception de peptidomimétiques". Phd thesis, INSA de Rouen, 2013. http://tel.archives-ouvertes.fr/tel-00924074.

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L'intérêt des composés organiques fluorés est de nos jours de plus en plus important en raison de leur large domaine d'application (agrochimie, nucléaire, matériaux, chimie médicinale...). Par exemple, en chimie médicinale, la présence d'un ou plusieurs atomes de fluor au sein de biomolécules conduit très souvent à une amélioration de leur profil thérapeutique. Par ailleurs, le cyclopropane, le plus petit et le plus tendu des cycloalcanes, permet également de modifier les caractéristiques pharmacologiques de composés biologiques de par sa géométrie inhabituelle. En effet, la rigidification structurale apportée par ce motif influe sur la biodisponibilité d'une biomolécule en améliorant sa sélectivité et son affinité pour un récepteur biologique. Dans ce contexte, nous avons choisi d'associer les propriétés remarquables de l'atome de fluor à la contrainte structurale du cyclopropane dans le but d'élaborer deux nouvelles classes de fluoropeptidomimétiques.Tout d'abord, nous nous sommes intéressés à la modification de la chaîne latérale d'acides aminés naturels en développant la synthèse des analogues cyclopropaniques fluorés de la méthionine, de la leucine, de la lysine et de l'arginine. Nous avons ensuite appliqué l'un de nos acides aminés cyclopropaniques fluorés à la synthèse totale de l'analogue fluoré d'un inhibiteur de la sérineprotéase NS3/4A, le TMC 435.Enfin, dans le but de proposer une voie de synthèse générale permettant l'accès aux pseudopeptides fluorés comportant un monofluorocyclopropane à la place du lien peptidique, nous avons développé une nouvelle stratégie basée sur une étape d'addition nucléophile de réactifs organométalliques sur des N-(tert-butanesulfinyl)-α-fluoroimines chirales.
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47

Hewlins, Stuart A. "Reactions of alkenes with nitrogen containing reagents". Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246192.

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48

Gandon, Vincent. "Nouvelles méthodes de synthèse à partir des complexes du ziconium". Reims, 2002. http://www.theses.fr/2002REIMS009.

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Ce mémoire est consacré à la présentation des nouvelles méthodes de synthèse que nous avons mises au point grâce aux complexes du zirconium. Dans un première partie, nous avons détaillé la préparation des complexes zirconocéniques, leurs propriétés et leurs applications en synthèse. Dans la deuxième partie, nous avons décrit une nouvelle méthode de préparation des cyclopropanes, à partir des aldhéhydes et des cétones, grâce à l'utilisation du complexe Cp2Zr(éthylène) et d'un acide de Lewis. Basée sur le concept de contraction déoxygénative des oxazirconacycles, cette réaction de cyclopropanation a ensuite été adaptée au cas des éthers allyliques, eux-mêmes transformés en cyclopropanes substitués avec une bonne diastéréosélectivité. Dans la troisième partie, nous nous sommes intéressés à l'activation des 3-silyloxy-2-aza-1,3-diènes. Nous avons traité ces hétérodiènes par le complexe Cp2Zr(but-1-ène) et obtenu des zirconaoxazolines C-silylées, suite à un arrangement de type rétro-Brook. La présence de ces intermédiaires particulièrs nous a permis de transformer les 3-silyloxy-2-aza-1,3-diènes en amide α-silylés, en amides α,β-insaturés ainsi qu'en β-cétoamides. Nous avons également constaté que les 2-aza-1,3-diènes étaient susceptibles de réagir avec les organomagnésiens, à condition d'introduire une quantité catalytique de Cp2ZrCl2 dans le milieu réactionnel. Cette découverte nous a amené à mettre au point une réaction plus générale d'éthylmagnésiation des imines, catalysée par des complexes du zirconium. Cette réaction fait l'objet de la quatrième partie de ce document. Des amines possédant un carbone quaternaire en α de l'atome d'azote ont ainsi été préparées très facilement à partir des cétimines.
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49

Lo, Wai-cheung. "Metal complexes of porphyrins and porphycenes in catalytic cyclopropanation and aziridination of alkenes /". Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19481731.

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50

Nzihou, Ange. "Cinétique de cristallisation de l'hydrate de cyclopropane : méthodes expérimentales et modélisation de la croissance". Toulouse, INPT, 1994. http://www.theses.fr/1994INPT045G.

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Notre travail a porte sur l'etude de la cinetique de cristallisation de l'hydrate de cyclopropane de type i. Le choix du systeme d'etude s'est porte sur le cyclopropane a cause des faibles pressions d'equilibre, inferieures a 10 bar, ce qui a permis la construction d'un cristallisoir en verre. Au cours de ce travail, nous avons mis au point un dispositif experimental qui a permis de mesurer la consommation de gaz et la granulometrie des cristaux d'hydrate formes. L'etape theorique nous a permis de representer la vitesse de croissance des cristaux d'hydrates en fonction des parametres cinetiques que sont la temperature, la force motrice, la vitesse d'agitation, la taille des cristaux et la sursaturation de la solution par les deux methodes de mesure utilisees. En utilisant les bilans de population et en faisant appel aux lois de cristallisation couplees aux phenomenes de transfert de matiere qui regissent la formation du reseau cristallin, nous avons pu modeliser la vitesse de croissance des cristaux d'hydrate de cyclopropane
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