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1
Warburton, Elizabeth Jean. "The metabolism of cycloalkanes by different species of Xanthobacter". Thesis, Nottingham Trent University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329184.
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2
Shirley, Neil John. "Synthesis of compounds of natural and unnatural origin by intramolecular alkylations". Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09PH/09phs558.pdf.
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3
Parkinson, Nigel Christopher. "Nucleoside and nucleotide analogues containing fluorine". Thesis, Durham University, 1993. http://etheses.dur.ac.uk/5639/.
Testo completoAbstract (sommario):
The work contained in this thesis is divided into four sections detailing the formation of (diethoxyphosphinyl)difluoromethylene substituted cycloalkanes and alkenes and their chemistry, as well as the syntheses of purine and pyrimidine substituted polyfluoroethers:(i) The methodology for the introduction of the (diethoxyphosphinyl)difluoromethylene group was studied and extended, with specific reference to cyclic systems. The group was successfully introduced into cyclic alkenes with (diethoxyphosphinyl)difluoro- methylene zinc bromide and saturated systems with (diethoxyphosphinyl)difluoromethyl lithium. The organolithium reagent was also shown to be capable of ring opening epoxides to yield alcohols ;(ii) The (diethoxyphosphinyl)difluoromethylene substituted cyclohexene derivative was further functionalised in a four step process to a new class of adenine and guanine based nucleotide analogues. Model studies were carried out on the (diethoxyphosphinyl)- difluoromethylene substituted cyclohexene derivative with a variety of reagents to introduce functionality at the double bond;(iii) The radical addition of (diethoxyphosphinyl)bromodifluoromethane and (diethoxyphosphinyl)difluoroiodomethane to cycloalkenes using ultraviolet photolysis and gamma-ray initiation were successfully carried out, thus opening up a new route into (diethoxyphosphinyl)difluoromethylene substituted cycloalkanes;(iv) The synthesis of purine and pyrimidine nucleoside analogues is described via the coupling of 2-amino-6-chloropurine, 6-chloropurine, silylated 5-fluorouracil and silylated uracil to various α-haloethers. The α-haloethers having previously been synthesised by radical chlorination of both cyclic and acyclic polyfluoroethers.
4
Gray, Gary. "The oxidation of cycloalkanes using dioxygen catalysed by homogeneous and supported metalloporphyrins". Thesis, University of York, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245972.
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Budkina, Darya S. "Ultrafast photophysical and photochemical dynamics of polyhalogenated alkanes, cycloalkanes, and transition metal complexes". Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1553686775405944.
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6
Navasero, Neenah. "Synthetic routes to non-symmetric tropones". Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101647.
Testo completoAbstract (sommario):
The synthesis of substituted non-symmetric tropones has proven to be a considerable synthetic challenge. Particularly, a 3,4,6-tnsubstituted tropone which is required for the total synthesis of CP-225,917 is currently being undertaken by our group.Two approaches towards the synthesis of substituted tropones are presented. Both utilize linear diene precursors which are closed to 7-membered cycloheptene rings via ring closing metathesis. In the first method, linear precursors are synthesized by addition of nucleophilic substituents to carbonyl groups to form alcohol groups. After forming the cycloheptene ring, the alcohol groups are eliminated to form the tropone. The second method uses an oxidation protocol to form a,(3-unsaturation on either side of a cycloheptenone precursor. An attempt towards the synthesis of the desired tropone required for the CP-225,917 synthesis is also presented.
The methods described here use simple inexpensive starting materials and provide access to tropone substitution not readily available through other means.
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McCleary, Michelle Angela, e n/a. "Synthetic and Structural Studies on the Novel Formation of Bicyclo[n.2.0]alkan-1-ols". Griffith University. School of Science, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040520.143342.
Testo completoAbstract (sommario):
Reaction of phenyl vinyl sulfoxide with the lithium enolates of simple ketones of varying ring size (cyclopentanone, cycloheptanone and cyclooctanone) under controlled cyclisation conditions followed by subsequent oxidation resulted in the formation of the bicyclo[n.2.0]alkan-1-ols 253-255, 262, 263, 265, 268 and 269 in conjunction with alkylated species 256, 257, 264, 266 and 267. The ratio of bicyclo[n.2.0]alkan-1-ols to alkylated ketone formation observed was dependent on a number of factors including the variation of enolate reactivity between the different ring sizes, conversion of phenyl vinyl sulfoxide, time, temperature and concentration of reaction and the stability and steric strain observed in the final bicyclo[n.2.0]alkan-1-ol product. X-ray crystal structures of 253, 262 and 265 were obtained and a structural study showed that as the overall steric strain in the bicyclo[n.2.0]alkan-1-ol product is decreased there is a corresponding increase in product distribution in favour of bicyclo[n.2.0]alkan-1-ol formation in conjunction with increased yields. Selected substituted and functionalised ketones (2-methylcyclopentanone, 2,6-dimethylcyclohexanone, 2-methylcyclohexanone and 1,4-cyclohexanedione mono-ethylene ketal) also reacted in the cyclisation reaction to give bicyclo[n.2.0]alkan-1-ols 270, 271, 277, 278, 281, 282, 285 and 286 in conjunction with alkylated products 272, 279, 280, 283, 284 and 287. Incorporation of substitution at the bridgehead and C2 position had a role in the preference of the major stereochemical isomer observed for a bicyclo[n.2.0]alkan-1-ol (n = 3, 4). A structural comparison of the X-ray crystal structures of 278, 281 and 286 indicated that the pseudo chair conformation of the six-membered ring influenced ring torsion and bond angles in the bicyclo[4.2.0]octanol ring system. Two model studies were selected to illustrate the potential application of the cyclisation process as methodology towards natural product synthesis or complex ring systems. No bicyclo[n.2.0]alkan-1-ol formation was evident in an intramolecular example using the starting ketone 291 in which the electrophile is tethered to the ketone. 2,6-Dimethyl-2-cyclohexen-1-one 301 considered as a model study towards the synthesis of the antibiotic mellolide, upon reaction with phenyl vinyl sulfoxide and oxidation displayed poor reactivity. The novel bicyclo[2.2.2]octanones 303, 304 and 305 were formed in very low yields. The lack of reactivity of the ketones 2,6-dimethyl-2-cyclohexen-1-one, 1,2-cyclohexanedione and 1,4-cyclohexanedione towards bicyclo[n.2.0]alkan-1-ol formation suggested that conjugation in the enolate prior to reaction with phenyl vinyl sulfoxide was not favourable. The non-reactivity of these ketones and the hindered ketone camphor indicated the potential limitations to the cyclisation methodology. However, conversion of the ketal functionality of 286 to a ketone resulted in the formation of the functionalised bicyclo[4.2.0]octanol 288 providing positive indications for further synthetic applications.
8
McCleary, Michelle Angela. "Synthetic and Structural Studies on the Novel Formation of Bicyclo[n.2.0]alkan-1-ols". Thesis, Griffith University, 2004. http://hdl.handle.net/10072/366615.
Testo completoAbstract (sommario):
Reaction of phenyl vinyl sulfoxide with the lithium enolates of simple ketones of varying ring size (cyclopentanone, cycloheptanone and cyclooctanone) under controlled cyclisation conditions followed by subsequent oxidation resulted in the formation of the bicyclo[n.2.0]alkan-1-ols 253-255, 262, 263, 265, 268 and 269 in conjunction with alkylated species 256, 257, 264, 266 and 267. The ratio of bicyclo[n.2.0]alkan-1-ols to alkylated ketone formation observed was dependent on a number of factors including the variation of enolate reactivity between the different ring sizes, conversion of phenyl vinyl sulfoxide, time, temperature and concentration of reaction and the stability and steric strain observed in the final bicyclo[n.2.0]alkan-1-ol product. X-ray crystal structures of 253, 262 and 265 were obtained and a structural study showed that as the overall steric strain in the bicyclo[n.2.0]alkan-1-ol product is decreased there is a corresponding increase in product distribution in favour of bicyclo[n.2.0]alkan-1-ol formation in conjunction with increased yields. Selected substituted and functionalised ketones (2-methylcyclopentanone, 2,6-dimethylcyclohexanone, 2-methylcyclohexanone and 1,4-cyclohexanedione mono-ethylene ketal) also reacted in the cyclisation reaction to give bicyclo[n.2.0]alkan-1-ols 270, 271, 277, 278, 281, 282, 285 and 286 in conjunction with alkylated products 272, 279, 280, 283, 284 and 287. Incorporation of substitution at the bridgehead and C2 position had a role in the preference of the major stereochemical isomer observed for a bicyclo[n.2.0]alkan-1-ol (n = 3, 4). A structural comparison of the X-ray crystal structures of 278, 281 and 286 indicated that the pseudo chair conformation of the six-membered ring influenced ring torsion and bond angles in the bicyclo[4.2.0]octanol ring system. Two model studies were selected to illustrate the potential application of the cyclisation process as methodology towards natural product synthesis or complex ring systems. No bicyclo[n.2.0]alkan-1-ol formation was evident in an intramolecular example using the starting ketone 291 in which the electrophile is tethered to the ketone. 2,6-Dimethyl-2-cyclohexen-1-one 301 considered as a model study towards the synthesis of the antibiotic mellolide, upon reaction with phenyl vinyl sulfoxide and oxidation displayed poor reactivity. The novel bicyclo[2.2.2]octanones 303, 304 and 305 were formed in very low yields. The lack of reactivity of the ketones 2,6-dimethyl-2-cyclohexen-1-one, 1,2-cyclohexanedione and 1,4-cyclohexanedione towards bicyclo[n.2.0]alkan-1-ol formation suggested that conjugation in the enolate prior to reaction with phenyl vinyl sulfoxide was not favourable. The non-reactivity of these ketones and the hindered ketone camphor indicated the potential limitations to the cyclisation methodology. However, conversion of the ketal functionality of 286 to a ketone resulted in the formation of the functionalised bicyclo[4.2.0]octanol 288 providing positive indications for further synthetic applications.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Science
Full Text
9
Rogers, Bruce. "Approaches to cyclobutane containing cage compounds". Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299584.
Testo completo
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Skibiński, Maciej. "Effect of gem-difluorination on the conformation of selected hydrocarbon systems". Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/7058.
Testo completoAbstract (sommario):
Owing to its unique electronic properties, the CF₂ group has the potential to affect the conformation and polarity of molecules. The Introduction provides an overview of the conformational effects induced by the incorporation of fluorine into hydrocarbons, e.g. gauche effect, 1,3-C,F bond repulsion and angle deviation in organofluorine compounds. A summary of synthetic strategies for the introduction of the gem-difluoride motif into organic molecules is also presented. In order to explore the conformational impact of the CF₂ group in alicyclic hydrocarbon systems, cyclododecane was employed as the molecular framework. In 1,1,4,4- and 1,1,7,7- tetrafluorocyclododecanes, two CF₂ groups replaced CH₂ units within the square [3333] cyclododecane ring where the spacing enables the CF₂ groups to occupy adjacent or opposite corner locations. In the case of 1,1,6,6-tetrafluorocyclododecane, one of the CF₂ groups was forced to the edge position, which changes the ring conformation dramatically. Strategic incorporation of two CF₂ groups is shown to either stabilise or significantly alter the conformation of the cyclododecane framework, a revealing conformational preference of the CF₂ group to locate at the corner rather than the edge position of hydrocarbon rings. The study extends to larger cycloalkanes, rectangular [3434] cyclotetradecanes and square [4444] cyclohexadecanes. The target cycloalkanes bearing two CF₂ units were assembled through a novel synthetic route, employing ring-closing metathesis (RCM) as the key step. X-Ray structure analyses revealed that the CF₂ groups occupy exclusively corner locations of these rings too. The spacing between the CF₂ moieties dictates the overall ring conformations and offers a useful tool for controlling molecular arrangement. An accelerating role of the CF₂ group, relative to the CH₂ group, on the ring-closing metathesis of C5-substituted 1,8-nonadienes has also been studied. Remarkably, the CF₂ group exhibited a similar reaction rate to that observed for nonadienes bearing 1,3-dioxolane or dimethylmalonate groups. This effect was rationalised by the thermodynamic stability of the cycloheptene products, rather than a Thorpe-Ingold effect.
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Yasrebi, Kaveh [Verfasser], Andreas [Gutachter] Hilgeroth, Sibel Gutachter] Süzen e Michael [Gutachter] [Lalk. "Synthesis and biological evaluation of trisindolyl-cycloalkanes and bis-indolyl naphthalene small molecules as potent antibacterial and antifungal agents / Kaveh Yasrebi ; Gutachter: Andreas Hilgeroth, Sibel Süzen, Michael Lalk". Halle (Saale) : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2020. http://d-nb.info/1237685796/34.
Testo completo
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Wang, Chang-Sheng. "Selective catalytic C(sp²)–H and C(sp³)–H bond functionalizations for the synthesis of phosphorus and nitrogen containing molecules". Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S106/document.
Testo completoAbstract (sommario):
Dans la thèse de doctorat, nous avons développé une approche efficace pour la modification rapide d'oxydes d'arylphosphines via la fonctionnalisation de liaisons C-H en position ortho du groupement P=O catalysée par le ruthénium (II) en présence des alcènes. Intéressement, l'ajustement du pH du milieu réactionnel permet de contrôler la sélectivité de la réaction à savoir alkylation or oléfination. La réduction des oxydes de phosphines fonctionnalisées permet la formation d'arylphosphines portant un carboxylate flexible. Dans le second objectif, un couplage C(sp3)–H /N-H oxydatif catalysé par le cuivre a permis l'alkylation d'hétérocycles à partir de (cyclo alcanes abordables. Ce protocole implique la formation de liaisons C (sp3)–N via une voie radicalaire générée par un clivage homolytique du peroxyde de di-tert-butyle et le piégeage du ou des radicaux par des catalyseurs au cuivre. Dans une troisième partie, nous avons utilisé ces processus radicalaires pour la fonctionnalisation le liassions C(sp3)–H benzylique d'oxyde de 2-alkylpyridines. Ces transformations impliquent un processus en cascade : estérification oxydative catalysée par le cuivre suivie d'un transfert d'atome d'oxygène. Enfin, des dérivés tosylés de pyridin-2-ylméthyl ont été obtenus avec des rendements élevés à partir des oxide de 2-alkylpyridines grâce à un réarrangement sigmatropic [3,3] du produit d'addition entre les oxides de 2-alkylpridine avec des chlorures de chlorure de benzènesulfonyles. De plus, les alkylnitrones subissent également ce réarrangement sigmatropique [3,3] pour donner des cétones α-tosylées après hydrolyseIn the first chapter, we have developed an efficient approach for the fast modification of arylphosphine oxides using ruthenium(II)-catalyzed C–H bond functionalization with alkenes. Interestingly, we have found that the selectivity of the reaction, namely alkylation versus alkenylation, is depending on the reaction pH. The reduction of the phosphine oxide allows the formation of aryl phosphines bearing a flexible pendent carboxylate. In the second objective, a copper-catalyzed oxidative C(sp3)–H/N–H coupling of NH-heterocycles with affordable (cyclo)alkanes was developed. This protocol involved C(sp3)–N bond formation via a radical pathway generated by a homolytic cleavage of di-tert-butyl peroxide and trapping of the radical(s) by copper catalyst.In a third part, benzylic C(sp3)–H acyloxylation of 2-alkylpyridine, 2-alkylpyrazine and 2-alkylthiazole compounds was achieved using simple aldehydes via a copper-catalyzed tandem reaction, involving oxidative esterification followed by O-atom transfer. Finally, pyridin-2-ylmethyl tosylate derivatives are obtained in high yields from 2-alkylpyridine N-oxides via a [3,3]-sigmatropic rearrangement of the adduct between 2-alkylpridine N-oxides with benzenesolfonyl chlorides. Moreover, alkylnitrones also underwant [3,3]-sigmatropic rearrangement to give α-tosylated ketones after hydrolysis
13
Rakotoalimanana, Andrianjafy Darwin. "Pyrolyse du n-butylcyclohexane à haute pression (100 bar) : application à la stabilité thermique des naphtènes dans les fluides pétroliers HP/HT". Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0029/document.
Testo completoAbstract (sommario):
L’objectif de cette thèse est de mieux comprendre les réactions de craquage thermique des naphtènes (hydrocarbures saturés cycliques) se déroulant dans les réservoirs pétroliers. Les naphtènes, représentant une famille importante de composés dans les huiles « Haute Pression/Haute Température » des gisements profonds, ont fait l’objet de très peu d’études dans ces conditions. La pyrolyse du n-butylcyclohexane a été étudiée à haute pression (100 bar) dans des réacteurs fermés en tubes en or, entre 300°C et 425°C. Le n butylcyclohexane produit majoritairement des n-alcanes (C1 à C4), d’autres naphtènes et des composés aromatiques. Un modèle cinétique complexe a été développé (833 réactions essentiellement radicalaires) ; il rend bien compte de nos résultats expérimentaux jusque 60% de conversion. L’extrapolation du modèle dans les conditions géologiques (température initiale de 160°C, gradient thermique de 2°C/MA et temps de réaction en millions d’années), montre que ce composé commence à se décomposer vers 180°C et que son temps de demi-vie correspond à 200-210°C. D’autres systèmes réactionnels impliquant des naphtènes, ont été également étudiés à 400°C et 100 bar. L’étude de la pyrolyse de la n-butyldécaline montre que cette molécule bicylique possède une réactivité similaire à celle du n-butylcyclohexane. L’étude à 400°C du mélange binaire n-octane/n-butylcyclohexane ne met pas en évidence d’effet cinétique significatif du n-butylcyclohexane sur la décomposition thermique du n-octane, mais l’extrapolation du modèle aux conditions géologiques montre que les naphtènes inhibent la décomposition des n-alcanes à basse température (200°C) et à haute pression (100 bar)This thesis aims at better understanding the thermal cracking reactions of naphthenes (saturated cyclic hydrocarbons), occurring in petroleum reservoirs. Naphthenes represent a significant fraction of “High Pressure/High Temperature” oils in deeply buried reservoirs; however, studies in these conditions are very limited in literature. The pyrolysis of n-butylcyclohexane is studied in a gold sealed tube reactor between 300 and 425°C, at 100 bar. n-Butylcylohexane mainly leads to n-alkanes (C1-C4), other naphthenes and aromatic compounds. A detailed model is developed (833 reactions, mainly free-radical reactions); a good agreement with our experimental results is reached up to a conversion of 60%. According to simulation results obtained by extrapolating to lower temperature, this compound starts to undergo thermal cracking at 180°C and its time of half-life corresponds to a temperature around 200-210°C, while considering the following burial scenario of an oil reservoir: initial temperature of 160°C and a heating rate of 2°C/MY (Million Years). Other chemical systems including naphthenes, are also studied at 400°C and 100 bar. The study of 1-n-butyldecaline shows, that this bicyclic compound and n-butylcyclohexane have a similar reactivity at 400°C. The study of the binary mixture n-butylcyclohexane/n-octane at 400°C does not provide any significant evidence of a kinetic effect of n-butylcyclohexane on the thermal decomposition of n-octane, but the extrapolation of our model at geological conditions shows that naphthenes are inhibitors of the decomposition of n-alkanes at low temperature (200°C) and at high pressure (100 bar)
14
Schneider, Marc Andre. "Iridium- und Rhodiumhydrido-Komplexe mit 1,8-Bis(diorganylphosphino)anthracen-Liganden als thermostabile homogene Katalysatoren für die Dehydrierung von Alkanen". [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968540732.
Testo completo
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Sirjean, Baptiste. "Étude cinétique de réactions de pyrolyse et de combustion d'hydrocarbures cycliques par les approches de chimie quantique". Thesis, Vandoeuvre-les-Nancy, INPL, 2007. http://www.theses.fr/2007INPL093N/document.
Testo completoAbstract (sommario):
Les carburants dérivés du pétrole constituent la première source mondiale énergétique et leur approvisionnement constitue un défi actuel majeur impliquant des enjeux économiques et environnementaux cruciaux. Une des voies les plus efficaces pour peser simultanément sur ces deux enjeux passe par la diminution de la consommation en carburant. La simulation numérique constitue dès lors un outil précieux pour améliorer et optimiser les moteurs et les carburants. Les modèles chimiques détaillés sont nécessaires pour comprendre les phénomènes d’auto-inflammation et caractériser la nature et les quantités de polluants émis. Ces modèles mettent en jeu un nombre très important d’espèces et de réactions élémentaires, pour une espèce donnée et pour lesquelles la détermination des données thermodynamiques et cinétiques est un problème crucial. La chimie quantique constitue un outil précieux permettant d’une part de déterminer de façon précise les données thermocinétiques pour bon nombre de systèmes chimiques et d’autre part de mieux comprendre la réactivité de ces systèmes. Dans ce travail, les réactions unimoléculaires de décomposition d’hydrocarbures monocycliques et polycycliques (amorçages, réactions moléculaires, ß-scissions, formations d’éthers cycliques) ont été étudiées à l’aide des méthodes de la chimie quantique. Un mécanisme détaillé de pyrolyse d’un alcane polycyclique a été développé à partir des données thermodynamiques et cinétiques et des corrélations entre structure et réactivité déterminées pour les cyclanes à partir des calculs quantiques. Les simulations effectuées à partir de ce modèle sont en très bon accord avec les résultats expérimentaux de la littératurePetroleum fuels are the world’s most important primary energy source and the need to maintain their supply is a major actual challenge involving both economical and environmental features. Decreasing fuels consumption is one of the more efficient ways to reconcile the goals of energy price and environmental protection. Numerical simulations become therefore a very important tool to optimize fuels and motors. Detailed chemical kinetic models are required to reproduce the reactivity of fuels and to characterize the amount of emitted pollutants. Such models imply a very large number of chemical species and elementary reactions, for a given species, and the determination of thermodynamic and kinetic data is a critical problem. Nowadays, quantum chemistry methods are able to calculate accurately thermodynamic data for a large number of chemical systems and to elucidate the reactivity of these systems. In this work we have used quantum chemistry to study the unimolecular reactions (initiation, molecular reactions, ß-scissions, cyclic ethers formations) involved in the decomposition of monocyclic and polycyclic hydrocarbons. From the results of quantum chemical calculations, a detailed chemical kinetic mechanism of the pyrolysis of a polycyclic alkane has been developed and validated against experimental data
16
Ucak-Astarlioglu, Mine Gunes. "The electronic structure and spectroscopy of diarylidene-cycloalkanones and their protonated cations". Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0506103-160044.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Worcester Polytechnic Institute.Keywords: polyene ketones; diarylidene-cycloalkanones; spectroscopy; electronic structure; protonated cations; photochemistry; electronic states. Includes bibliographical references (p. 189-191).
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Pi, i. Boleda Bernat. "Supramolecular studies on the behaviour of different chiral cycloalkane-based compounds as receptors, gelators and surfactants". Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/400575.
Testo completoAbstract (sommario):
En aquesta tesi, s’han estudiat quatre diferent sistemes supramoleculars com a receptors, gelificadors o tensioactius. S’ha analitzat la influència de diferents factors estructurals de la molècula senzilla en la seva propietat supramolecular final. S’han utilitzat diferents estratègies per a preparar els compostos estudiats. La combinació de diferents tècniques ens ha permès entendre millor aquests sistemes obtenint un resultat sinèrgic. Els resultats d’aquesta tesi estan dividits en quatre capítols:
1) Diferents receptors d’anions tripodals s’han sintetitzat i la seva complexació amb diferents anions s’ha estudiat. Fent servir RMN, les energies de Gibbs de complexació s’han calculat i la seva afinitat de cordinació s’ha estudiat. Mitjançant càlculs teòrics, l’estructura dels diferents complexes s’ha predit. També, la termodinàmica dels sistemes estudiats s’ha calculat. Els càlculs teòrics ens han permès entendre i racionalitzarels resultats experimentals.
2) Tres famílies diferents de gelificadors basats en carbocicles que contenen dos grups amida s’han estudiat per tal de determinar la influència de la mida de l’anell, les substitucions de l’anell i l’estereoquímica de la molècula en les seves habilitats gelificants. Usant el test de la inversió del tub i racionalitzant-lo amb diferents paràmetres de solubilitat, les habilitats gelificants dels diferents compostos s’han determinat. Aquest estudi s’ha acompanyat amb RMN d’alta resolució. L’agregació s’ha estudiat mitjançant càlculs teòrics, els quals estan en acord amb els espectres de dicroïsme circular obtinguts dels xerogels. Finalment, fent servir SEM, s’ha determinat la morfologia dels agregats.
3) Quatre diferents tensioactius tipus bola s’han sintetitzat i el seu caràcter com a tensioacitus s’ha estudiat per tal de determinar la influència de l’esteroquímica i la regioquímica en el seu comportament com a tensioactius. Fent servir el mètode de la gota penjatn, la variació de la tensió superficial amb la concentració s’ha analitzat. Hem desenvolupat un nou mètode per predir l’estructura dels tensioactius agregats a la superfície. Finalment, les tècniques de cryoTEM i SAXS ens han permès estudiar la morfologia i la mida dels agregats.
4) Al darrer capítol, qutre tensioactius depenents del pH s’han sintetitzat. L’estudi supramolecular de les seves propietats s’ha dut a terme usant diverses tècniques. Aquests tensioactius mostren un interessant comportament àcid-base adequat per a possibles aplicacions biològiques. És per això que s’han estudiat com a possibles nous vectors no-virals per a teràpia gènica fent servir diferents tècniques biofísiques i biològiques. Els resultats mostren que no són tòxics i que tenen propietats interessants per ser usats com a vectors.In this thesis, four different supramolecular systems were studied as receptors, gelators or surfactants. The influence of different structural factors of the single molecule on the final supramolecular properties was analysed. Different strategies were used to prepare the studied compounds. The combination of different techniques leads us to better understand these systems obtaining synergistic results. Results of this thesis are divided in four chapters: 1) Different tripodal anion receptors were synthesised and their complexation with different anions were studied. Using NMR, complexation Gibbs energies were calculated and the binding affinity were studied. Using theoretical calculations, the structure of the complexes were predicted. Also, thermodynamics of the host-guest system were calculated and theoretical calculations lead us to rationalise the experimental results. 2) Three different families of cycloalkane diamide-based gelators were studied to determine the influence of the ring size, the substitutions of the ring and the stereochemistry on the final gelation abilities. Using the tube inversion test and rationalising it with different solubility parameters, the gelation ability was determined. This study was accompanied by high resolution NMR. Self-assembly was studied using theoretical calculations and circular dichroism. Results show that all of the studied gels are chiral despite some of the monomers are meso compounds. Then, using SEM, the morphology of the aggregates was determined. 3) Four different bolaform amphiphiles were synthesised and their behaviour as surfactants were studied to determine the influence of the stereochemistry and the regiochemistry on the final surfactant behaviour. Using the pendant drop method, the variation of the surface tension with the concentration was analysed. We developed a new method to predict the structure of the self-assembled surfactants at the surface. CryoTEM and SAXS were used to determine the morphology and size of the aggregates. 4) In the last chapter, four pH-dependent β-amino acid-based surfactants were synthesised. Supramolecular properties of these systems were studied using pendant drop method, cryoTEM, theoretical calculations, different physicochemical titrations, circular dichroism, UV-vis absorption and DLS. These surfactants show interesting acid-base behaviour suitable for biological applications. They have been studied as potential new non-viral vectors for gene therapy using different biophysical and biological techniques. Results show that these surfactants are not toxic and they have interesting features to be used as vectors.
18
Fresu, Sonia [Verfasser]. "Synthesis of bridged bicycles and macrocycles from cycloalkanones via tandem reactions and ring expansion / Sonia Fresu". Dortmund : Universitätsbibliothek Technische Universität Dortmund, 2004. http://d-nb.info/1011532913/34.
Testo completo
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Therene, Hubert. "Etude physico-chimique de la fraction dite saturée des bitumes". Rouen, 1987. http://www.theses.fr/1987ROUES006.
Testo completoAbstract (sommario):
Les composés saturés des bitumes c'est-à-dire les alcanes et les cyclanes sont séparés des bitumes par précipitation sélective et chromatographie d'adsorption. Ils sont analysés par des méthodes spectrométriques et chromatographiques. L'influence des composés saturés sur les démixtions et les propriétés mécaniques dynamiques du bitume est déterminée par microscopie en contraste de phase et en lumière polarisée
20
Lai, Guan-Hong, e 賴冠宏. "The Conformations of Cycloalkanes and The Conformations and Biochemical Activities of Both Epothilones and Macrolides". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/40138928306288659632.
Testo completoAbstract (sommario):
碩士國立成功大學
化學系碩博士班
91
We discuss the conformations of cycloalkanes(C12H24、C14H28、C16H32、C18H36、C20H40) and the relations between conformations and biochemical activities of both Epothilones and Macrolides by semi-emprcial AM1 quantum mechanical calculation methods with PC-SPARTAN. The calculation results show that the torsional energy of C-C bond in cycloalkanes is so low, even lower than 20 kJ/mol, reveals cycloalkanes are easily affected by external force so as to occur many conformation variations. In conformation, only dihedral angle locating the torsional position changes larger than any other positions where is less affected. The cyclopropyl C-C bond has the larger torsional energy than usual ones, which means the conformation near cycloprpyl is more rigid, and not too easily be changed. For cycloalkanes, the results of conformational analysis indicate that the simultaneous torsions of several dihedral angles can move the arrangement of carbon atoms in cycloalkanes. Despite the variation is not so apparent, the C-H bonds oscillate for the torsion of C-C bond. Those cyclopropyl cycloalkanes can fasten the local conformation of cycloalkanes, so that the oscillating angles of C-H bonds near cyclopropyl would be smaller. From the conformation analysis of medicines, the flapping range of the side chain and functional groups in the medical cyclopropyl compounds would reduce largely because of the rigid cyclopropyl local conformation. Compared with the large flap of other conformations' medical side chain and functional groups, those which get cyclopropyl conformations in them are the medical compounds whose side chain and functional groups react with the active center much possibly. We think this is the main reason which results the difference of activities of medicines.
21
Lu, Wan-Sam, e 呂宛珊. "Theoretical study on the gas-phase ion-molecule SN2 and E2 reactions of halides of cycloalkanes". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/e9496v.
Testo completoAbstract (sommario):
碩士國立中正大學
化學暨生物化學研究所
103
This thesis consists of three chapters. We studied the bimolecular nucleophilic substitution (SN2) and bimolecular elimination (E2) reactions of cyclic and noncyclic alkyl halides. In Chapter 1, we studied RX + SH( R=ethyl (C2H5), isopropyl (C3H7), tert-butyl (C4H9), cyclopentyl (C5H9), cyclohexyl (C6H11), n-propyl (C3H7), n-butyl (C4H9), n-pentyl (C5H11), n-hexyl (C6H13)；X=Cl、Br、I). For reactions of C4H9X (tert-butyl，X=Cl、Br、I) + SH and C5H9I (Iodocyclopentane) + SH, the elimination reactionas were favored . The substitution reactions were the most feasible pathway for the other reactions. When the reactant is cyclopentyl halide, the differences in barrier heights between substitution and elimination reactions ranged from 0.5 to 2.6 kcal/mol. The elimination reactions would compete with the substitution reactions. In chapter 2, we studied RX + CN( R=ethyl (C2H5), isopropyl (C3H7), tert-butyl (C4H9), cyclopentyl (C5H9), cyclohexyl (C6H11), n-propyl (C3H7) , n-butyl (C4H9), n-pentyl (C5H11), n-hexyl (C6H13)；X=Cl、Br、I) reactions. According to theoretical study of transition state theory (TST), the elimination reactions were favored over the substitution reactions for the C5H9X (cyclopentyl，X=Cl、Br、I) + CN. Especially, the rate constants of the elimination reactions were higher than theose of the substitution reactions by 1.6 to 15.6 times for the reactions of C5H9X (cyclopentyl，X=Cl、Br、I) + CN. The rate constants of the elimination reactions were higher than theose of the substitution reactions by 2.6 to 6 times for the reactions of C6H11X (cyclohexyl, X=Cl、Br、I) + CN. The substitution and the elimination pathways are competitive for the reactions of C5H9X and C6H11 X.l. In Chaper 3, we studied the identity exchange SN2 reactions of RX + X(R=ethyl (C2H5), isopropyl (C3H7), tert-butyl (C4H9), cyclopentyl (C5H9), cyclohexyl (C6H11), X=Cl、Br、I). The energy barrier of C5H9Cl + Cl(4.4kcal/mol) is lower than that of C3H7Cl + Cl(6.3 kcal/mol) by 1.9 kcal/mol. The deuterium KIEs of both cyclic and noncyclic halides were predicted to be normal with those of cyclic halides being slightly higher.
22
Kim, Jungchul. "Natural product synthesis via cyclobutanes : part I, Asymmetric synthesis of (+)-byssochlamic acid, part II, An approach to the nootropic agent huperzine A". Thesis, 2000. http://hdl.handle.net/1957/32732.
Testo completoAbstract (sommario):
PART I. Asymmetric syntheses of both natural (+)- and nonnatural (-)-
byssochlamic acid via a [2+2] photoaddition-cycloreversion strategy are
described. X-ray crystallographic analysis of the cyclohexylamine salt 99 showed
that the structure of the monomethyl ester 100 from esterase hydrolysis of 44
was originally misassigned as 56. The enantiomeric relationship of the two
diolides 106 and 70 permitted syntheses of nonnatural byssochlamic acid (-)-3
and natural byssochiamic acid (+)-3 from enantiopure alcohol (+)-64 and from its
enantiomer (-)-110, respectively. Through the use of (��)-103 to reach both
enantiomers of byssochlamic acid (3) and subsequent epimerization of the npropyl
chain, it was proved that the cis configuration of the two alkyl substituents
is strongly preferred in the natural product.
PART II. An asymmetric approach towards the nootropic agent huperzine A
is described. Formation of cyclobutane 122 with the desired stereochemistry was
accomplished using intramolecular [2+2] photoaddition of the enantiopure enone
121. Attempts to prepare the methoxypyridine system via an azadiene Diels-
Alder reaction were unsuccessful. However, intramolecular Michael addition of
181 produced silyl ether 182 which was converted into the pyridone 187 by
treatment with hydrogen fluoride followed by selenoxide elimination. Attempts to
effect the key sigmatropic rearrangement of ketone 197 into a direct precursor of
huperzine A were unsuccessful.Graduation date: 2001
23
Shirley, Neil John. "Synthesis of compounds of natural and unnatural origin by intramolecular alkylations / by Neil John Shirley". Thesis, 1987. http://hdl.handle.net/2440/21578.
Testo completo
24
Kesavan, V. "Studies On Catalytic Oxygen Transfer Reactions In Organic Synthesis". Thesis, 1999. http://etd.iisc.ernet.in/handle/2005/1619.
Testo completo
25
李晏成. "Silicon-directed hydroxymethylation of ��-trimethylsilyl cycloalkanones through anodic oxidation". Thesis, 1992. http://ndltd.ncl.edu.tw/handle/33232531056085255143.
Testo completo
26
張文昇. "Photo-cyclization of a-iodo cycloalkanones bearing an allenic side chain". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/56860367154407452025.
Testo completoAbstract (sommario):
碩士國立清華大學
化學系
89
The main goal of the synthesis is to study the Photo-induced cyclization reaction of α- iodo cycloalkanones bearing an allenic side chain. We first use the α- iodo cycloalkanone compound 71a-b as starting material, introduce the side chain of allene from β-position successfully by 1,4-Michael addition and then follow with Photo-induced Electron Transfer（PET） cyclization reaction, we obtain the 5、5-fused, 6、5-fused bicycle compounds 73a-b and 74a-c. Besides, we compare the difference of reaction by using Iodide and Slow-addition radical cyclization. From the results, we conclude that the products are all the same. It is avoidable to use the reagent that generate radical because of the allenic side chain can proceed the Photo-induced Electron Transfer cyclization reaction. It is also more convenient of purification. We can construct the structure of 5、5-fused and 6、5-fused bicycle compounds efficient and take advantage of in the synthesis of natural compounds such as (+)-Axamide-4 or (+)-Axisonitrile-4.
27
Shun-Yuan, Luo, e 羅順原. "α-Carbonyl Radical Cyclization of Cycloalkanones Bearing an Allenic Side Chain". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/55199829837733977359.
Testo completoAbstract (sommario):
碩士國立清華大學
化學系
88
Abstract We prepared α-iodo ketone, and used iodo-atom transfer to form α-keto radical. α-iodo radical is cyclized with allenic side chain to form vinyl spiro compound.
28
Hsien-Hsun, Lin, e 林賢勳. "Photoinduced Spiro Cyclization of α-Iodo Cycloalkanones Bearing an Allenic Side Chain". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/54008135954626882676.
Testo completo
29
林賢勳. "Photoinduced spiro cyclization of A-iodo cycloalkanones bearing an allenic side chain". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/54097484830229205380.
Testo completo
30
Lee, Fang-Chen, e 李芳城. "Iodine Atom Transfer Cyclization of a-Iodo Cycloalkanones Mediated by AlCl3 / ICl". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/37909763745965174778.
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31
Zhang, Jianbin. "Ring-opening of cycloalkane epoxides and aziridines with aromatic amines : toward the total synthesis of pactamycin". Thèse, 2009. http://hdl.handle.net/1866/3794.
Testo completoAbstract (sommario):
Résumé
Cette thèse consiste en trois thèmes résumés dans les paragraphes ci-dessous. L’influence de différents groupements protecteurs du groupe hydroxyle lors des réactions d’ouverture des cis- et trans- 3-hydroxy-1,2-époxycycloalcanes a été étudiée. Il a été montré que Yb(OTf)3 constituait un catalyseur doux pour l’ouverture régiosélective de cycles afin d’obtenir les -anilino cycloalcanols correspondants avec de bons rendements. Le chauffage du milieu réactionnel dans le toluène comme solvant a permis d’augmenter la cinétique de la réaction, au dépend du rendement. La partie aniline a été régiosélectivement introduite en position vicinale du groupe hydroxyle ou éther afin d’obtenir un unique régioisomère. La même tendance a été observée avec les époxydes du 3-azidocyclohex-1-ène et du 3-carbamate correspondant. Le temps de réaction a été réduit lorsque Yb(OTf)3 a été dissous dans l’acétonitrile. Le triflate d’ytterbium (III) a également été utilisé comme catalyseur pour l’ouverture de cycle régiosélective d’aziridines non-activées sur des cyclohexanes portant des substituants azotures ou éthers de benzyle. L’ion azoture ou l’aniline forment les produits trans correspondants, donnant alors accès à des diamines vicinales avec de bons rendements.
Un éther ω-alcoxy p-méthoxybenzylique racémique, inhibiteur de HDAC, a été ainsi préparé en huit étapes synthétiques (rendement total de 26%) à partir du 1-((tert-butyldiphénylsilyl)oxy)hept-6-èn-2-ol. Ceci représente un progrès par rapport à la précédente méthode (9 étapes, rendement total de 16%). La métathèse croisée se montre particulièrement efficace et pratique dans cette stratégie et l’alkylation par le trichloroacétimidate de p-méthoxybenzyle en présence de Sc(OTf)3 améliore le rendement global de la synthèse.
Un aminoalcool présent dans la pactamycine et contenant le squelette carboné, les groupements fonctionnels et la stéréochimie requise a été synthétisé en 27 étapes à partir de la L-thréonine. La méthodologie décrite dans cette thèse permet la synthèse de cet intermédiaire clé à l’échelle multigramme.Abstract Ring-opening reactions of epoxides and aziridines have been extensively studied. The influence of different protecting groups on the hydroxyl group in the ring-opening reactions of cis- and trans- 3-hydroxy-1,2-cycloalkane epoxides with aromatic amines was studied. It was shown that Yb(OTf)3 in toluene was a mild catalyst for regioselective ring-opening, to give -anilino cycloalkanols in good yields. Heating the reaction mixture accelerated the rate of the reaction, albeit at the expense of yield. The aniline moiety was regioselectively added at the carbon furthest from the hydroxyl or ether group to yield a single regioisomer. The same trend was also observed with 3-azidocyclohex-1-ene epoxides and the corresponding 3-carbamates. The reaction time became shorter when acetonitrile was used as solvent, possibly due to the homogeneous medium. Ytterbium(III) triflate has also been used as the catalyst for the regioselective ring-opening of unactivated aziridines in cyclohexanes having an azide or benzyl ether substituent. Azide ion or aniline forms the corresponding trans-products giving access to vicinal diamines in good yields. A racemic ω-alkoxy p-methoxy benzyl ether HDAC inhibitor has been prepared in 8 synthetic steps (26% overall yield) from 1-((tert-butyldiphenylsilyl)oxy)hept-6-en-2-ol. This is an improvement over the published method (9 steps, 16% overall yield). The cross-metathesis method proved to be efficient and practical in this strategy, and alkylation using p-methoxybenzyl trichloroacetimidate in the presence of Sc(OTf)3 improved the overall yield of the synthesis. An amino alcohol that contains all the core carbons, functional groups and the required stereochemistry present in pactamycin was obtained starting from L-threonine over 27 steps. The methodology described in this thesis allows for a synthesis of this key intermediate on a multigram scale.
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Alshanqiti, Ahmed M. "Cycloalkane Metathesis using a Bi-metallic System: Understanding the Effect of Second metal in Metathesis Reaction". Thesis, 2018. http://hdl.handle.net/10754/630968.
Testo completoAbstract (sommario):
Over the past decades, since the discovery of a single–site silica-supported catalyst for the alkane metathesis reaction by our group, we have been extensively working on the development of supported catalytic systems for the improved alkane metathesis reaction. During these developments, we understand the reaction mechanism and reached a new perspective for the synthesis of various supported bimetallic systems via the surface organometallic chemistry (SOMC) approach. Recently, with this bi-metallic system, we got a very high TON (10000) in propane metathesis reaction. As these catalysts are very efficient for linear alkanes we thought to apply it for cyclo-alkanes specifically, for cyclo-octane metathesis expecting better activity. Besides, the value of the ring alkanes are higher than the linear alkanes.
The current work demonstrates a combination of [(ΞSi−O−)W(Me)5] and [(ΞSi− O−)Ti(Np)3 pre-catalyst with several supports (SiO2-700, SBA-15 and MCM-41) for metathesis of cyclooctane. The catalysts have been synthesized and fully characterized by elemental
analysis (EA), FT-IR and NMR spectroscopies. After fully characterization the bi-metallic catalyst was tested for metathesis of cyclooctane with highest ever TON 2500 as compared to that of mono-metallic catalyst where we got 430 TON. Which again corroborates our prediction that bimetallic catalysts are better catalysts than monometallic catalysts.
33
LIAO, BEN-RUI, e 廖本瑞. "Counterattack reagent hexamethyldisilane in syntheses of allyltrimethylsilanes,oximes and the photoreaction of ▫-trimethylsilyl cycloalkanones". Thesis, 1989. http://ndltd.ncl.edu.tw/handle/16731515827772518479.
Testo completo