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1
Jones, D. "The synthesis of aryl ethers." Thesis, Swansea University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637726.
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The synthesis of biaryl ethers is a process of importance in many fields within the chemical industry. Generally, the Ullmann ether synthesis is employed, though improvements in the general method have not been commonplace since the inception of the process at the turn of the century. By reinvestigating the parameters present, it was found that the use of cuprous iodide in a solventless reaction led to high yields of diaryl ethers. Further improvements were developed by the implementation of ultrasound in conjunction with lower reaction temperatures, with similarly high yields being afforded. Study was then undertaken to investigate the applicability of electrophilic bromination of various aromatic moieties. Thus, phenol, 2-methoxyphenol and aniline were examined in relation to the amount of ortho-bromination occurring with reagents such as 1,3-dibromo-5,5-dimethylhydantoin and N-bromosuccinimide in the presence of solid supports. These studies indicated that the use of solid supports, especially Amberlyst 15 and XN1010 and Montmorillonite K10 realised high degrees of bromination, though in the case of aniline the natural tendency to realise bromination in the para-position reduced the observed effectiveness of the process. By the implementation of acetyl hypobromite and N,N-dibromourethane, good para selectivity was found for the bromination of toluene in the presence of solid supports, though when applied to nitrobenzene, bromination of the straight chain alkane present at the internal standard present for gas chromatography analysis occurred. The use of molecular bromine in conjunction with solid supports such as Montmorillonite K10 led to high yields of 1-bromonaphthalene.
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Fruteau, de Laclos Anne-Marie F. (Anne-Marie François). "Cleavage of benzyl aryl ethers by chlorine." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70291.
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In order to extend application of the gel-degradation mechanism of delignification, model compounds of the general structure (3,4-dimethoxyphenyl)-CH(OR)R$ sp prime$ were treated at room temperature with increasing charges of molecular Cl$ sb2$ in glacial HOAc.Catalytic amounts of Cl$ sb2$ cleaved benzyl aryl ether bonds (OR=2-methoxy-4-methylphenoxy) before any ring chlorination occurred. Yields of cleavage decreased in the order: R$ sp prime$=H; R$ sp prime$=$-$CH$ sb2$-2-methoxyphenoxy; R$ sp prime$=$-$CH(CH$ sb2$OH)-2-methoxyphenoxy. These results support the concept that the delignification of wood pulp by chlorine results from benzyl aryl ether cleavage. The conditions of the reaction, as well as control reactions with hydrochloric acid, suggest that the cleavage is due to conventional acid hydrolysis induced by chlorine. The experimental evidence does not rule out another possible mechanism in which the cleavage is initiated by molecular chlorine.
Benzyl ether links were generally stable in models of the benzyl alkyl type, whose primary reactions were ring chlorination. A large excess of chlorine caused side-chain displacement, hitherto considered the primary reaction in the solubilization of lignin.
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Chamberlin, Rachel Alexandra. "Some substitution reactions of aryl sulfides and aryl ethers with aliphatic amines in DMSO : the mechanism of base catalysis." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5213/.
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The reactions of several nitro-aromatic substrates with the aliphatic amines, n- butylamine, pyrrolidine and piperidine in DMSO have been studied. Reaction of the amines with trinitroaromatic compounds, such as ethyl thiopicrate, phenyl thiopicrate and phenyl 2,4,6-trinitrophenyl ether, was shown to occur in two well separated processes. A rapid reaction, occuring at an unsubstituted ring position, resulted in the formation of a a-adduct; this was followed by a slower substitution reaction, resulting in the displacement of the 1-substituent to give the amino-substituted compound. Kinetic results show that in the formation of the σ-adduct, the rate determining step changes from nucleophilic attack by amine with n-butylamine to proton transfer from the zwitterionic intermediate with piperidine; with pyrrolidine the proton transfer step is partially rate limiting. The substitution reaction involving n-butylamine is not base catalysed indicating nucleophilic attack, the k(_1) step, is rate determining. However, the reactions with pyrrolidine and piperidine are subject to general base catalysis showing proton transfer is involved in the slow step. The rate limiting step is thought to be the proton transfer from the zwitterionic intermediate to base. A single substitution reaction was seen for the reaction of the less activated 1-substituted 2,4-dinitrophenyl and 1-substituted 2,4-dinitronaphthyl compounds. The rate limiting step again changes from nucleophilic attack with n-butylamine to proton transfer with pyrrolidine and piperidine. The uncatalysed, k(_2), pathway was detected during the reaction of the 1-substituted 2,4-dinitrophenyl compounds. Those were the least activated substrates studied and as the effectiveness of the base catalysed step relative to the uncatalysed decomposition of the intermediate decreases with decreasing activation of the substrate, detection of the uncatalysed step became possible. Kinetic and equilibrium studies were also made on the reaction of morpholine with several phenyl ethers. Results were compared with those for piperidine with the same substrates, the values of the kinetic and equilibrium constants were as expected considering morpholine has the same steric requirements as piperidine but is considerably less basic.
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May, Leslie J. "Design of functionalized cyclic aryl ethers and alkenes and their subsequent ring-opening polymerization." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62792.pdf.
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Leung, Joe Cho Tak. "Radical fluorination methods for the synthesis of aryl mono-, di-, and tri- fluoromethyl ethers." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45726.
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New reagents for selective radical fluorine transfer have been identified and utilized to develop two novel photochemical reactions to access fluorinated methoxy arenes. I have discovered that SelectfluorTM can be employed as a radical fluorinating agent, leading to the development of a photochemical methodology (in aqueous alkaline SelectfluorTM solutions containing 2-aryloxyacetic acids) for the synthesis of aryl fluoromethyl, difluoromethyl, and trifluoromethyl ethers. In the second reaction developed, acetone N-fluorobenzensulfonimide solutions containing 2-aryloxyacetic acids will promote a different, milder, photosensitized decarboxylative fluorination reaction capable of delivering more electron rich aryl fluoromethyl ethers, and aryl difluoromethyl ethers. Density Functional Theory calculations support the assertion that radical intermediates are involved in fluorination.
Alkoxyl radical reactions have also been investigated. I have found that the rate of alkoxyl 5-exo cyclization onto a silyl enol ether is only marginally faster than cyclization onto a trisubstituted alkene. The assumption that secondary and primary alkoxyl radicals display similar cyclization behaviour was proven unsound, and primary alkoxyl 5-exo cyclization onto a simple terminal alkene is likely faster than published rates. Alkoxyl radical 1, 5-hydrogen atom transfer was studied in the context of a radical relay cyclization methodology. I have demonstrated that primary, secondary and tertiary alkoxyl radicals may be successfully employed in the relay cyclization of 5 (5-exo), and 6 (6-endo) membered carbocyclic rings.
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Liang, Theresa. "Silver-Mediated Trifluoromethoxylation of Aryl Nucleophiles and Synthesis of 3-Deoxy-3-Fluoromorphine." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10547.
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Fluorine incorporation has become increasingly important in pharmaceutical applications. Upon fluorination and incorporation of fluorinated moieties such as trifluoromethoxy groups, many small molecules become more bioavailable and metabolically stable and additionally can better cross the blood-brain-barrier. This thesis describes the development of a method mediated by silver salts for the synthesis of pharmaceutical-like trifluoromethoxylated compounds via \(C-OCF_3\) bond formation. Additionally the synthesis of 3-deoxy-3-fluoromorphine via late-stage fluorination of morphine is described as well as in vitro and in vivo evaluation of 3-deoxy-3-fluoromorphine as a potential analgesic.Chemistry and Chemical Biology
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Chatalova, Sazepin Claire. "Radical methods for the synthesis of fluoroalkanes and fluoromethyl aryl ethers and copper-catalyzed three-component carboetherification of alkenes." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55907.
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Fluorinated molecules have become popular compounds among pharmaceuticals. The introduction of fluorine atoms on bioactive compounds has indeed the potential to improve their biophysical properties. Given the utility of fluorinated substituents on pharmaceuticals, fluorine chemistry has become an area of intensive research. Despite the progress made in selective fluorination, however, radical fluorination has been limited notably due to the paucity of atomic fluorine sources. In this thesis, the uncovering of new atomic fluorine sources and the development of new radical fluorination methods will be described.
Chapter 1 presents the importance of fluorinated molecules and the currently available fluorinating agents. A discussion on radical fluorination is presented that includes the most recent advances in the field.
In Chapter 2, the exploratory work on the ability of electrophilic N—F fluorinating agents to transfer fluorine to alkyl radicals is detailed. Peresters were chosen as radical precursors and reacted with traditionally electrophilic fluorine sources, NFSI and Selectfluor®. Under those conditions, various fluoroalkanes could be synthesized in good yields.
A radical fluorination method subsequently developed using Selectfluor® is described in Chapter 3. The ability of phenoxyacetic acid derivatives to undergo fluorodecarboxylation under UV-light excitation using Selectfluor® was demonstrated. The methodology was successfully applied to the synthesis of mono- and difluoromethyl aryl ethers in 40 to 86% yields.
Chapter 4 details the application of the photofluorodecarboxylation to the synthesis of trifluoromethyl aryl ethers. It was found that the wavelength required for the substrate’s excitation led to the decomposition of the desired products. A method using benzophenone as a photosentizer was developed allowing the use of another wavelength to promote the reaction, which proved to be substrate dependent. The use of a faster fluorine transfer agent, XeF2, allowed the synthesis of trifluoromethoxy arenes in good yields.
A copper catalyzed difunctionalization of alkenes, developed in collaboration with Prof. Jieping Zhu, is presented in Chapter 5. This reaction allows the direct introduction of alkyl nitriles via C—H activation. A C—O bond and a C—C bond were created in a single step. A wide range of α substituted styrenes were difunctionalized in yields up to 82%.Science, Faculty of
Chemistry, Department of
Graduate
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Stridfeldt, Elin. "Hypervalent Iodine Reagents in Metal-Free Arylations and Vinylations : Investigation of Suitable Coupling Partners and Synthesis of New Reagents." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-141580.
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This thesis concerns the development of metal-free reactions to obtain carbon-heteroatom and carbon-carbon bonds. This is achieved by transferring carbon ligands from hypervalent iodine reagents to suitable nucleophiles. The bulk of the work presented herein concerns arylation of oxygen and nitrogen nucleophiles, using the well-known diaryliodonium salts as aryl sources. In the first project, O-arylation of the oxime ethyl acetohydroxamate was studied. It was found that electron-poor as well as electron-rich aryl moieties could be transferred successfully to this nucleophile. Furthermore, the protocol could be extended to a sequential one-pot synthesis of benzo[b]furans. This method allowed for a fast synthesis of the natural product stemofuran A and formal syntheses of other natural products. In a successive project, O-arylation of hydroxide and aliphatic alkoxides was investigated. It is known that electron-poor aryl moieties can be transferred to these nucleophiles in moderate to high yields. However, combined with more electron-rich diaryliodonium salts, a large amount of side products were formed. These were suppressed upon addition of aryne traps, suggesting that aryne pathways are competing with the desired ligand coupling. It was also observed that secondary alcohols were oxidized to the corresponding ketones. The mechanism for this oxidation was investigated and aryne pathways could be excluded. Instead we suggest that the carbinol hydrogen gets deprotonated via an internal mechanism, after the alkoxide has coordinated to the iodonium salt. Highly sterically congested alkyl aryl ethers could be obtained in high yields by combining tertiary alcohols with ortho-blocked diaryliodonium salts. Next, N-arylation of secondary acyclic amides was studied using acetanilide as the model substrate. This procedure was suitable for transfer of electron-poor as well as ortho-substituted aryl moieties, but attempts to transfer very electron-rich aryl groups were unsuccessful. On the other hand, the amides displayed a complementary reactivity, allowing phenylation of electron-rich amides. In the final project, a one-pot synthesis of the cyclic iodonium reagent vinylbenziodoxolone is presented. These compounds have not been explored as reagents earlier. Initial screenings showed that the vinyl moiety could be transferred to nitrocyclohexane with opposite regioselectivity compared to the acyclic analogue of the reagent.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.
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Lindstedt, Erik. "Metal-Free O- and C-Arylation with Diaryliodonium Salts." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-140944.
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This thesis concerns the development of metal-free applications using diaryliodonium salts. The first project describes an arylation protocol of allylic and benzylic alcohols in aqueous media. The method proceeds under mild conditions and the ether products were obtained in moderate to good yields. The methodology was also expanded to include arylation of phenols, giving diaryl ethers in good to excellent yields. In the second project, an arylation method that included a wider range of aliphatic alcohols was developed. The scope of accessible alkyl aryl ethers was studied and included a comparative study of phenylation and nitrophenylation of various alcohols. Finally, a formal metal-free synthesis of butoxycain was performed, illustrating the applicability of the developed method. The third project focused on the limitations and side reactions occurring in Chapter 2 and 3. First, an approach to access symmetric diaryl ethers via arylation of hydroxide was presented. This reaction gave rise to a number of side products, which we hypothesized to originate from aryne-type intermediates. A mechanism for the formation of these side products was suggested, supported by trapping and deuterium labeling experiments. Oxidation of the alcohol to the corresponding ketone was also observed and the mechanism of this interesting side reaction was investigated. The latter was suggested to proceed via an intramolecular oxidation without the involvement of radicals or arynes. The fourth project covers a method to synthesize highly sterically congested alkyl aryl ethers via arylation of tertiary alcohols using diaryliodonium salts. The method displayed a broad scope of tertiary alcohols and was also suitable for fluorinated alcohols. The final project detailed in this thesis deals with C-arylation with diaryliodonium salts, showcasing nitroalkanes as well as a nitro ester as suitable nucleophiles for metal-free arylation.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.
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Neto, Carlos Alberto Felipucci. "Mn(III)porfirinas sintéticas como modelos químicos do Citocromo P-450: a O-desalquilação oxidativa de aril éteres substituídos como modelos de drogas por iodosilbenzeno." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-15082008-081032/.
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Reações de O-desmetilação oxidativa estão entre as várias oxidações realizadas pelas enzimas do citocromo P-450. Entretanto, poucos estudos de O-desmetilação catalisadas por enzimas do citocromo P-450 ou modelos químicos baseados em metaloporfirinas sintéticas têm resultado em dúvidas acerca do mecanismo da O-desmetilação destes compostos orgânicos. Neste trabalho, foi estudada a O-desmetilação oxidativa, com PhIO, do benzil metil éter e alguns de seus derivados para substituídos (com os grupos doadores de elétrons -OCH3 e -CH3 e os grupos retiradores -NO2 e -Cl) catalisada pelas Mn(III)P [Mn(TPP)]Cl, [Mn{T(4-N-MePy)P}](PF6)5, [Mn(TMP)]Cl, [Mn(TDCSPP)]Cl e [Mn(TFPP)]Cl para verificar o efeito destes diferentes catalisadores na conversão e seletividade de produtos da O-desmetilação oxidativa e avaliar o efeito dos diversos substituintes citados no mecanismo de O-desalquilação. Inicialmente, realizou-se o estudo das oxidações catalíticas do metil benzil éter. Todas as reações catalisadas pelas MnP se mostram seletivas, sendo que o benzaldeído foi o produto comum a todas as oxidações. A melhor condição encontrada foi 1:50:1224 (catalisador/oxidante/substrato). Em relação às reações com os substratos contendo os substituintes na posição -para, as reações de oxidações catalíticas do p-metóxibenzil metil éter por PhIO não se mostraram tão seletivas quanto as do metil benzil éter, mostrando claramente que o grupo metóxi alterou a reatividade do aril éter original. Mesmo assim, o p-metoxibenzaldeído ainda foi o produto principal, sendo a conversão ao álcool p-metoxibenzílico observada em escala menor. Já com o substrato p-nitrobenzil metil éter, novamente o efeito provocado pelo substituinte na posição para no anel benzênico pôde ser percebida na distribuição final dos produtos, sendo que houve seletividade total para a formação de p-nitrobenzaldeído em detrimento ao álcool p-nitrobenzóico. Em relação aos dois últimos substratos da série proposta, metil p-metilbenzil éter e metil p-clorobenzil éter, de um modo geral, as reações realizadas com o p-clorobenzil metil éter não se mostraram tão seletivas quanto as do metil p-nitrobenzil éter, mostrando que o grupo cloro aumentou a reatividade do cloroéter em relação ao éter com o substituinte nitro- original. Mesmo assim, o p-clorobenzaldeído foi o produto principal, sendo a conversão ao álcool p-clorobenzílico observada em menor escala. Em relação às reações de oxidação do p-metilbenzil metil éter, observou-se que os resultados experimentais são semelhantes aos encontrados para o metil benzil éter. Esses resultados corroboram o principal mecanismo proposto para os sistemas modelo do citocromo P-450 que envolve abstração inicial do átomo de hidrogênio, o mecanismo por recombinação de oxigênio.O-dealkylation oxidative reactions are among the several oxidations accomplished by the cytochrome P-450 enzymes. However, few studies on O-dealkylation catalyzed by such enzymes or chemical models based on synthetic metalloporphyrins have resulted in doubts concerning the mechanism of these reactions involving organic compounds. In this work, we studied the oxidative O-dealkylation by PhIO of benzyl methyl ether and some of its para-substituted derivatives (with the electron donor groups -OCH3 and -CH3 and the electronwithdrawing groups -NO2 and -Cl) catalyzed by the following Mn(III)P: [Mn(TPP)]Cl, [Mn{T(4-N-MePy)P}] (PF6)5, [Mn(TMP)]Cl, [Mn(TDCSPP)] Cl, and [Mn(TFPP)]Cl. Our aim was to verify the effect of these different catalysts on the conversion yields and product selectivity, as well as evaluate the effect of the several substituents on the ether on the O-dealkylation mechanism. We initially studied the catalytic oxidation of methyl benzyl ether. All the reactions catalyzed by the various MnPs were selective, and benzaldehyde was the product common to all oxidations. The best reaction condition was catalyst/oxidant/substrate molar ration = 1:50:1224. As for the reactions with the substituted substrates, the catalytic oxidation of p-methoxybenzyl methyl ether by PhIO was not as selective as the ones of methyl benzyl ether, clearly showing that the methoxy group affects the reactivity of the original aryl ether. Nevertheless, p-methoxybenzaldehyde was still the main product, being the conversion to p-methoxybenzylic alcohol observed in minor amount. With the substrate p-nitrobenzyl methyl ether, the effect of the electronwithdrawing substituent in the para- position of the aromatic ring could be observed in the final product distribution once again, and total selectivity toward the formation of p-nitrobenzaldehyde to the detriment of p-nitrobenzoic alcohol was observed. In relation to the two last substrates of the proposed series, the methyl p-methylbenzyl and methyl p-chlorobenzyl ethers, the reactions accomplished with p-chlorobenzyl methyl ether were not as selective as the ones carried out with methyl p-nitrobenzyl ether, showing that the chloro group increased the reactivity of the chloro-ether in relation to the ether with the original nitro- substituent. Even so, p-chlorobenzaldehyde was the main product, being the conversion to the p-chlorobenzylic alcohol observed in smaller amount. Concerning the oxidation reactions of p-methylbenzyl methyl ether, the experimental results were similar to those obtained in the case of methyl benzyl ether. These results corroborate the main mechanism proposed for the cytochrome P-450 model systems, which involves initial hydrogen atom abstraction, followed by oxygen rebound.
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Dingley, Alison Mary. "Molecular orientation in poly (aryl ether ether ketone)." Thesis, University of Leeds, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303429.
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Hernandez, Raul S. "Perfluorocyclobutyl aryl ether polymers for proton exchange membranes." Connect to this title online, 2008. http://etd.lib.clemson.edu/documents/1211388507/.
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Oates, Christine. "X-ray diffraction studies of poly(aryl-ether-ether-ketone) and related polymers." Thesis, Keele University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280899.
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Neilson, Andrew R. "Perfluorocyclobutyl aryl ether polymers a modular approach to tailored emission /." Connect to this title online, 2008. http://etd.lib.clemson.edu/documents/1211390898/.
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Platon, Mélanie. "Propriétés et performances de phosphines ferrocéniques dans le couplage C-O, C-S et C-N : nouvelles méthodologies de synthèse au palladium." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00818998.
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Les ligands multidentes montrent généralement de très bonnes activités dans la catalyse organométallique au palladium à faibles charges. Parmi ces ligands, l'utilisation des ligands polyphosphines ferrocéniques mènent à des résultats intéressants. Des systèmes catalytiques palladium/triphosphine ferrocénique robustes ont permis d'obtenir d'une part des diarylamines et d'autre part des éthers d'aryle et d'hétéroaryle avec de faibles charges catalytiques. Des calculs théoriques de DFT sur le cycle catalytique lors de la formation d'éthers d'aryle et d'hétéroaryle ont été réalisés. La présence d'un troisième groupement phosphino permettrait de stabiliser les états de transition et accélèrerait l'élimination réductrice. Les triarylamines ont pu être obtenues à l'aide d'une diphosphine ferrocénique avec une charge de 2 mol% de palladium. Des résultats modérés à excellents ont été obtenus. Enfin, les thioéthers d'aryle et d'hétéroaryle ont été obtenus avec d'excellents résultats à l'aide d'une tétraphosphine ferrocénique en présence de 0,2 mol% de palladium
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Pagé, Danny J. Y. S. "Neutron and gamma radiation effects on the viscoelastic behaviour of poly(aryl ether ether ketone)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22776.pdf.
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Douglas, Judy E. "Design, synthesis and characterization of naphthalene-based poly(aryl ether)s." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ32333.pdf.
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MacKinnon, Sean M. "Design, synthesis and characterization of novel functional poly(aryl ether)s." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ60965.pdf.
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Haworth, Ian Stuart. "N.M.R. and computational studies of polymer structure." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257184.
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Wails, David. "The synthesis and characterisation of perfluoralkyl substituted poly(aryl ether sulfone)s." Thesis, University of York, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283429.
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Yeomans, Kevin A. "Novel poly(aryl ether)s containing nitrile groups : synthesis, characterization and cross-linking studies." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=67538.
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Four novel aromatic difluoride compounds were synthesized for use as monomers in nucleophilic aromatic displacement polymerization reactions. Attempts were then made to polymerize these monomers with a series of bisphenols, using potassium carbonate as a base, in a dipolar aprotic solvent as in equation 1. eqalign qquad{& rm K sb2CO sb3 cr rm F{-}Ar{-}F + HO{-}Ar{-}OH quad& rm quad longrightarrow quad quad bigl(O{-}AR{-}O{-}Ar bigr) sb{n} cr& rm Dipolar aprotic cr& rm solvent cr& rm 160-195 sp circ C cr} eqno(1) sing the reaction above, several novel poly(aryl ether)s have been produced and some of their physical properties, such as glass transition temperature and thermal stability, have been investigated. The polymers all contain nitrile groups which have potential to form cross-links upon heating, thereby increasing the use temperature and solvent resistance of the resulting materials. This cross-linking potential was investigated. Also, polymers containing the 9,10-dicyanophenanthrene moiety were prepared and then reacted with cuprous chloride and phthalonitrile to give poly(aryl ether)s containing copper phthalocyanine groups.
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Cox, Robert John. "Ullmann etherification." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/25968.
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Formation of the diaryl ether moiety remains a challenging target for organic synthesis despite modern technologies, however, better understanding of older techniques often leads to improvements. The copper-catalysed Ullmann ether synthesis, whilst attractive in many ways, is frequently problematic due to the inherent irreproducibility of the reaction on scale up. Little is yet known about the mechanism of the reaction and conflicting views are rife within the scientific community. In a well-studied example, we show that the potassium iodide formed during the reaction slows catalysis. Additionally, the deprotonation of phenol is complicated by the insolubility of the inorganic base. This results in a beneficial outcome, providing a rate enhancement and reduction of by-products, which can be further exploited to provide lower stoichiometries, improved selectivity and greater functional group tolerance. The development of an improved, more reproducible procedure in combination with reaction calorimetry has allowed the mechanism to be studied in intricate detail. Excellent agreement with a mechanistic model has led to further insight into the enigmatic aryl halide activation and provides good evidence for a single electron transfer mechanism. In addition, evidence for a dynamic catalyst resting state has been observed which adds to the complexity of the mechanism. This, in turn, leads to a fine balance of concentration and electronic effects that prove vital to the rate of reaction.
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Datta, Gopal K. "Heck Reactions with Aryl Chlorides : Studies of Regio- and Stereoselectivity." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9202.
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Mao, Min. "Synthesis and Characterization of Highly Functional Substituted Stilbene Copolymers and Semi-crystalline Poly(aryl ether sulfone)s." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/29028.
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Novel, highly functional rod-like copolymers have been synthesized by alternating copolymerization of N, N, Nâ , Nâ -tetraalkyl-4, 4â -diaminostilbenes (TDAS) with maleic anhydride. Dynamic light scattering, 2H solid state NMR and persistence length measurement reveal high chain rigidity of the polymer backbone. Double quantum heteronuclear local field solid state NMR spectroscopy (2Q-HLF Solid State NMR) has been employed to investigate the chain structure of 13C labelled copolymer. The torsional angle of the H-13C-13C-H part of the anhydride ring was zero degrees, indicating an all cis configuration of the H-13C-13C-H moiety of the anhydride ring.
Rod-coil block copolymers containing rigid polyampholyte blocks were designed and synthesized by addition-fragmentation chain transfer (RAFT) copolymerization. The rigid polyampholytes blocks were formed by hydrolysis of alternating copolymers and the flexible coil block consists of poly(oligo(ethylene glycol) methacrylate). The rod-coil block copolymers form polyion complex (PIC) aggregates even when the polyampholyte blocks are charge imbalanced. The aggregates did not dissociate upon the addition of high concentrations of NaCl unlike the dissociation of flexible polyampholytes in NaCl solution. These unique solution properties are induced by â like-charge attractions' of the rigid polyampholytic alternating copolymer chains.
An example, of what is birefringent to be a novel class of material, has been prepared which enables the control of the birefringence of a polymer film by controlling the rotation of aromatic groups pendant to the polymer backbone.
A linear rigid bisphenol monomer, 4,4â -dihydroxyterphenyl (DHTP), has been incorporated into poly(aryl ether sulfone)s (PAES) in a study to impart crystallization to these amorphous polymers. Three bisphenols, 4, 4â -isopropylidenediphenol, 4, 4â -(hexafluoroisopropylidene)diphenol and 4,4â -dihydroxybiphenyl have been copolymerized with DHTP and dichlorodiphenylsulfone. Only the segmented polysulfone containing 50% BP and 50% DHTP was semi-crystalline. This PAES had a melting temperature (Tm) 320oC in the first heating cycle of a DSC measurement and the presence of crystallites was confirmed by wide angle X-ray diffraction (WAXS).Ph. D.
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Xie, Donghang. "Part I: Synthesis and Ring Opening Polymerization of Macrocyclic Monomers for Production of Engineering Thermoplastics." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30539.
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Part I: Single sized, pure arylene ether macrocycles ranging from 30 to 60 atom ring sizes were synthesized in good yields (up to 83%) by the two component method under high dilution conditions. These macrocycles have unsymmetric structures containing sulfone/ketone or sulfone/phosphine oxide functional groups and have relatively low melting points. The melt ROP of the single sized macrocycles to form poly(arylene ether)s exhibits two stage characteristics: the first stage is very fast, driven by the large entropy difference between cyclics and linears; the second stage is very slow and is diffusion controlled due to the high viscosity created in the first stage reaction. The latter stage leads to incomplete polymerization at the low initiator concentrations (1-3 mol%). At high initiator concentrations (5-7 mol%), 100% conversion is reached due to improved initiator distribution in macrocycles; however, this reduces molecular weights of the polymers. The molecular weight is found to build up very rapidly, independent of conversion, reaction time and type of initiator. The ROP is initiated by CsF and alkali phenoxides. The efficiency of the alkali counterion is generally in the order of Cs+>K+>Na+, while a phenoxide initiator is more efficient than a fluoride initiator. It is also found that the Cs counterion leads to highest degree of crosslinking. The ROP of cyclic oligomeric mixtures is also reported for comparison; the study shows that the molecular weight depends on time and conversion, and that the conversion is sensitive to the content of linear impurities and the average ring size of cyclic mixtures.
Part II: Polyrotaxanes are novel polymeric materials comprised of linear polymer molecules and threaded macrocycles with no covalent bond between the two components. With potential movements of the cyclic component and judicious combinations of the two components of different properties, these materials have brought interesting changes of physical properties, such as morphology, crystallinity, solubility, viscosity, etc. In this part of the dissertation, a new family of polyrotaxanes with poly(arylene ether)s as backbones and crown ethers as cyclic components are described. These include linear poly(arylene ether) based polyrotaxanes and hyperbranched poly(ether ether ketone) based polyrotaxanes; both are synthesized via aromatic nucleophilic substitution reactions. Preliminary studies show that these polymers exhibit great enhancement of solubility. The polymers form emulsions in water and methanol which are normally non-solvents for the poly(arylene ether) backbones. In some cases, they are even soluble in water to form a clear solution. The attempted syntheses of polyrotaxanes using aromatic macrocycles described in Part I was not successful, with no indication of threading.Ph. D.
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Osegueda, Juan. "Synthèse et caractérisation de poly(aryl éther cétone amide)s." Thesis, Rouen, INSA, 2016. http://www.theses.fr/2016ISAM0022/document.
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Certaines applications (notamment dans l'aéronautique) demandent des polymères thermostables semi-cristallins avec des résistances et des températures de fonctionnement de plus en plus élevées (Tg supérieures à 170°C) tout en conservant de bonnes propriétés de mise en œuvre (Tf ne dépassant pas 350°C) aptes aux procédés industriels. Ce projet de thèse porte sur la synthèse et la caractérisation de nouveaux polymères hautes performances de type poly(aryl éther cétone amide)s à partir d'un monomère de type EKKE aux extrémités acide carboxylique. Ainsi, trois voies de synthèse des amides par condensation ont été étudiées : entre les acides carboxyliques et les isocyanates, entre les chlorures d'acyle et les amines, et entre les acides carboxyliques et les amines par phosphorylation. La comparaison des propriétés thermiques et leurs corrélations avec les structures chimiques des poly(aryl éther cétone amide)s aromatiques et semi-aromatiques obtenus sont particulièrement détailléesSome demanding applications (especially in aerospace) require more and more semi-crystalline thermostable polymers with high temperature resistance and durability (Tg above 170 °C) while maintaining good processing properties (Tm not exceeding 350°C) suitable for industrial manufacturing.This work deals with the synthesis and characterization of new high performance poly(aryl ether ketone amide)s polymers from an EKKE monomer with carboxylic acid extremities. Thus, three amide condensation synthetic routes were studied: between carboxylic acids and isocyanates, between acyl chlorides and amines, and between carboxylic acids and amines by phosphorylation. The thermal properties and their correlation with the chemical structures of the obtained aromatic and semi-aromatic poly(aryl ether ketone amide)s are compared and especially detailed
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Verma, Ravi Kant. "A study of the damage accumulation process in poly(aryl ether ketone ketone) and its AS4 carbon fiber reinforced composites." Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/43146.
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This thesis presents the results of a study done on the damage accumulation process in poly(ether ketone ketone) and its AS4 carbon fiber reinforced composites. The damage accumulation process was studied as a function of applied heat treatment. This study is the result of a project funded by duPont and was done in part to explain the dramatic change in fatigue properties observed at duPont as the applied heat treatment is changed.
The mechanical properties were characterized using a battery of tests. The quenched composite systems have lower moduli, but higher toughness and elongations. The quenched systems also have the best fatigue performance and therefore, it can be concluded that the quenched composite systems have the best potential as far as industrial applications are concerned. Quenching has other advantages in industrial applications. These include decreased chances of operator error, and decreased processing times.
The damage accumulation process was characterized using the acoustic emission method and also the drop in stiffness during flexure testing. It has been observed that the ultimate mechanical properties show a weak dependence on the applied heat treatment, whereas the damage accumulation process changes dramatically. A model has been developed to simulate the damage accumulation process. This model has then been used to predict the fatigue S-N curve in stroke control and to qualitatively relate it to the available fatigue data in stress control.Master of Science
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Smith, Craig R. "Metal-Catalyzed Reactions of Ethene: Asymmetric Hydrovinylation and Palladacycle-Mediated Low Pressure Vinylation of Aryl and Vinyl Halides." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274734379.
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Verma, Ravi Kant. "A study of the damage accumulation process in poly(aryl ether ketone ketone) and it's [sic] AS4 carbon fiber reinforced composites /." This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-06112009-063316/.
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Milton, Edward J. "Pd catalysed C-C & C-O bond formation using bis-(dialkyl/diarylphosphino)ferrocene ligands." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/1022.
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A brief introduction explaining phosphine ligand properties, Pd catalysed cross-coupling reactions; the importance of the steps involved in the catalytic cycle (oxidative addition, transmetalation & reductive elimination), mechanistic studies and a comparison of various reactions will give an overview of important cross-coupling reactions and their limitations. The development of a “super-concentrated” (5M) Pd catalysed Kumada type coupling reaction has been developed for coupling a range of aryl bromide and chloride substrates with the Grignard reagents ((p-CF₃-C₆H₄)MgBr)) and PhMgBr in methyl-tetrahydrofuran (Me-THF). Using a range of bidentate ligands such as bis-phosphinoferrocenyl ligands, good conversions were achieved using small amounts of solvent; up to 10 times less than typical procedures in THF. The unsymmetrical Pt complexes of the form [Pt(P-P)Br₂], [Pt(P-P)(Ph)Br] and [Pt(P-P)Ph₂] have been synthesised and characterised. The variations of substituents on the ligand system and the steric bulk have been shown to have a dramatic effect on the rate of transmetalation. The results provide one explanation why 1,1’-bis(di tert-butylphosphino)ferrocene (dtbpf), an excellent ligand for certain Suzuki reactions, is quite poor in reactions where transmetalation is more difficult. Palladium dichloride complexes of the ferrocenylphosphine based ligands 1,1’-bis- (diphenylphosphino)ferrocene (dppf), 1,1’-bis-(diisopropylphosphino)ferrocene (dippf) and 1,1’-bis-(di-tert-butylphosphino)ferrocene (dtbpf) have been shown to be active in the Hiyama cross-coupling of p-bromoacetophenone and vinyltrimethoxysilane (CHCH₂Si(OMe₃)) in the presence of TBAF under thermal heating and microwave conditions. Ligands with the optimum balance for promoting the transmetalation, oxidative addition and reductive elimination steps along the reaction pathway have been identified. Competition experiments are consistent with slow transmetalation being an issue with the Hiyama reaction relative to the Suzuki coupling. A novel protocol has been developed for the synthesis of aryl-alkyl ethers via C-O bond activation under Pd catalysed conditions. Utilising the unsymmetrical 1-bis-(ditertbutyl-1’- bis-diphenylphosphino)ferrocene (dtbdppf) under optimised conditions with silicon based nucleophiles and NaOH or TBAF as an activator, the formation of methyl, ethyl, n-propyl and n-butyl ethers with a range of aryl halides was achieved in good yield.
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Addo, Isaac D. "Diazonium 4-(trifluorovinyloxy) Perfluorobutanesulfonyl Benzenesulfonimide Zwitterionic Monomer Synthesis." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etd/3137.
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3-Diazonium- 4-(trifluorovinyloxy) - perfluorobutanesulfonyl benzenesulfonimide zwitterionic monomer (see figure 1) is proposed to be polymerized and further act as a new electrolyte for Polymer exchange membrane fuel cells (PEMFCs). One reason is that, the aromatic trifluorovinyl aryl ether (TFVE) group can easily be homopolymerized to aromatic perfluorocyclobutane (PFCB) polymer. Furthermore, the diazonium moiety in the monomer is expected to covalently attach the electrolyte to the carbon electrodes support. The perfluoroalkyl(aryl) sulfonimide (PFSI) pendant provides good chemical and mechanical stability as well as better proton conductivity. Several multi-step synthetic schemes are designed to obtain such monomer from perfluoroalkyl(aryl) sulfonimide (PFSI). Among them, the purified coupling product 4-OCF2CF2Br-3-NO2-PhSO2(M) SO2C4F9 from the first approach was successfully completed. The next stages of the work will involve dehalogenation, reduction, and diazotization to achieve the targeting monomer. All the intermediates were characterized by 1H and 19F NMR and FT-IR spectroscopy.
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Ndzie, Elias. "Etude de la nucléation et de la croissance cristalline au cours du dédoublement par cristallisation préférentielle auto-ensemencée de dérivés 5-méthyl-5-alkyl (ou 5-aryl) hydantoïnes." Rouen, 1998. http://www.theses.fr/1998ROUES072.
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Le dédoublement par cristallisation préférentielle de dérivés 5-alkyl-5-alkylhydantoïnes : 5-éthyl-5-méthylhydantoïne (12H), et des dérivés 5-méthyl-5-(4-Xphényl)hydantoïnes : X = méthyle (17H), chloro (pCl61H), méthoxy (pMeO61H) et bromo (pBr61H) est réalisé selon le procédé auto-ensemencé AS3PC à une échelle de 35mL puis étendu à 2 litres pour les dérivés 12H et pBr61H. Le suivi de l'évolution de la population de particules pendant la cristallisation permet de conclure que l'effet d'entraînement n'est pas le fait d'un mécanisme unique. Pour le dérivé 12H, il est le résultat d'une action combinée de croissance cristalline et de nucléations. Dans le cas du dérivé pBr61H, seule la croissance cristalline est observée.
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Maddaluno, Jacques. "Synthèse énantiosélective de composés d'intérêt biologique : approche de polyols vicinaux par aldolisation stéréocontrôlée, approche de bêta-amino esters par addition de Michael stéréocontrôlée sous haute pression." Paris 6, 1986. http://www.theses.fr/1986PA066240.
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La réaction d'aldolisation des benzoylaryacetates avec l'acétaldéhyde fait ressortir la capacité de ce synthon à effectuer un transfert d'asymétrie. Etude de la réactivité des alcoxy-3 acroléines. L'addition d'amines primaire sur des crotonates à haute pression permettent d'obtenir de meilleures sélectivités
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Figadère, Bruno. "Les composes organomanganeux mixtes : addition 1-2 selective sur des aldehydes ou des cetones portant un groupe fonctionnel, enolisation regioselective de cetones : application en synthese." Paris 6, 1987. http://www.theses.fr/1987PA066371.
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Les reactifs organomanganeux rmnx(x=cl, br, i; r=n-, sec- t-alkyl, alcenyl, aryl, alcynyl) s'additionnent aux aldehydes et cetones fonctionnels pour donner selectivement les alcools correspondant avec d'excellents rendements. Les reactifs rmnz(z=nphme) enolisent les cetones avec une excellente regioselectivite. Les enolates manganeux ainsi prepares sont tres aisement acyles, silyles, alkyles, hydroxyalkyles, avec des rendements de 60% a 90%, a la temperature ambiante
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Denys, Goument Colombe. "Dicétones-1,4 thiosubstituées." Rouen, 1988. http://www.theses.fr/1988ROUES023.
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Lei, Yun. "Synthesis of alkyl aryl ethers, thioethers, and sulfones." 1995. http://hdl.handle.net/1993/18820.
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Chen, Chi-Ren, and 陳啟任. "Reactions of Ruthenium Complexes with Terminal Aryl Alknyes and 2-Ethynylphenyl Vinyl Ethers." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/30761817478462958022.
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博士國立臺灣大學
化學研究所
104
Herein, we report that η5-pentadienyl ruthenium complex (η5-C5H7)(PPh3)2RuCl (1) is an efficient catalyst for the synthesis of 1,4-disubstituted butenynes in THF from the dimerization of aryl alkynes with a catalyst loading as low as 1-2 mol % under mild conditions, furnishing the (Z)-butenyne as the major product in the moderate yield along with a small amount of the E isomer. When aryl group which contains the substituent in the ortho position, the catalytic procedure results seem to indicate that the steric effect affects the yields of the desired enyne product more than the electronic effect. Dimerization reactions in different solvents showed that oxygen-containing solvents such as THF, diethyl ether, and acetone are better solvents than nitrogen-containing solvents. O-containing solvents are known to have relatively weaker coordinating power than the N-containing solvents. These results possibly indicate that the process could be assisted by the weak coordination between a solvent molecule and the metal center to stabilize the active intermediate. Treatment of a phenyl alkyne with 1 and KPF6, both in stoichiometric quantities, gives a phenyl phosphonium salt 6, whose structure has been confirmed. A series of synthesis of polyaryl phosphonium salts (APS) by cyclotrimerization of various aryl alkynes are also induced by a stoichiometric amount of the ruthenium η5-pentadienyl complex (η5-C5H7)(PPh3)2RuCl (1). A mechanism consisting of continuous insertion reactions of aryl alkynes into Ru-C bonds is proposed for the formations of enynes and APSs. In second study, catalytic cyclization reactions of three 2-ethynylphenyl vinyl ether 7a, 7b-Z and 7d in various alcohol are efficiently catalyzed by [Ru]Cl to give the benzoxepine derivatives, respectively. Surprisingly, in CH2Cl2, 7a and 7b containing no methyl and one methyl substituted vinyl groups undergo different skeletal rearrangement processes involving cleavage of C≡C and C=C bonds, respectively, in their reactions with [Ru]Cl. For both 7a and 7b, the terminal triple bonds are converted to the vinylidene ligands, then different [2+2] cycloadditions of the vinyl group with either the Cα=Cβ or the Ru=Cα bonds of the vinylidene ligand are proposed to take place. In the reaction of 7a, with no methyl group, the [2+2] cycloaddition process involves the vinylidene Cα=Cβ bond leading to formation of a bicyclic carbene intermediate followed by cleavage of the original C≡C triple bond, to give the cationic γ,δ-unsaturated vinylidene complex 9a which contains the trans-form double bond detected by coupling constant in NMR spectrum. The skeletal rearrangement of 7b-Z and -E, with one terminal methyl group on the vinyl unit, is believed to proceeds via a different [2+2] cycloaddition process involving the Ru=Cα bond, followed by cleavage of the C=C double bond of the original vinyl group to afford the carbene complex 14b. The structure of 14b is determined by single crystal X-ray diffraction analysis. Thus in the reaction of [Ru]Cl with a similar aryl vinyl ether 7c containing two terminal methyl groups on the vinyl unit, only the vinylidene complex 16c is isolated with no C-C bond formation. In addition, this catalytic cyclization is inhibited by the presence of a terminal methyl group on the vinyl unit trans to the phenolic oxygen atom as in the case of 7b-E. We also found that hydrolysis of i-propenyl phenyl ether to phenol probably occurs prior to cyclization to lead the formation of carbine complex 18d. Labeling experiments using 13C and 2D isotopes lead to better discernment of the skeletal rearrangement of the enyne system.
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Edouard, Guy Anthony. "Late Transition Metals Supported by Aryl Ethers and Phenoxides Bearing Pendant Phosphines: Mechanistic Insights Relevant to Ether C-O Bond Cleavage." Thesis, 2016. https://thesis.library.caltech.edu/9349/1/2016_0102.Edouard_ThesisRevised.pdf.
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Terphenyl diphosphines bearing pendant ethers were prepared to provide mechanistic insight into the mechanism of activation of aryl C–O bonds with Group 9 and Group 10 transition metals. Chapters 2 and 3 of this dissertation describe the reactivity of compounds supported by the model phosphine and extension of this chemistry to heterogenous C–O bond activation.
Chapter 2 describes the synthesis and reactivity of aryl-methyl and aryl-aryl model systems. The metallation of these compounds with Ni, Pd, Pt, Co, Rh, and Ir is described. Intramolecular bond activation pathways are described. In the case of the aryl-methyl ether, aryl C–O bond activation was observed only for Ni, Rh, and Ir.
Chapter 3 outlines the reactivity of heterogenous Rh and Ir catalysts for aryl ether C–O bond cleavage. Using Rh/C and an organometallic Ir precursor, aryl ethers were treated with H2 and heat to afford products of hydrogenolysis and hydrogenation. Conditions were modified to optimize the yield of hydrogenolysis product. Hydrogenation could not be fully suppressed in these systems.
Appendix A describes initial investigations of bisphenoxyiminoquinoline dichromium compounds for selective C2H4 oligomerization to afford α-olefins. The synthesis of monometallic and bimetallic Cr complexes is described. These compounds are compared to literature examples and found to be less active and non-selective for production of α-olefins.
Appendix B describes the coordination chemistry of terphenyl diphosphines, terphenyl bisphosphinophenols, and biphenyl phosphinophenols proligands with molybdenum, cobalt, and nickel. Since their synthesis, terphenyl diphosphine molybdenum compounds have been reported to be good catalysts for the dehydrogenation of ammonia borane. Biphenyl phosphinophenols are demonstrated provide both phosphine and arene donors to transition metals while maintaining a sterically accessible coordination sphere. Such ligands may be promising in the context of the activation of other small molecules.
Appendix C contains relevant NMR spectra for the compounds presented in the preceding sections.
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Davies, Katherine. "An Iterative synthesis of oligo-vinyl ethers and applications thereof." Thesis, 2012. http://hdl.handle.net/1828/3900.
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An iterative protocol is a highly efficient strategy for the generation of large, complex molecules that has been applied in many different subfields of organic synthesis. The use of a tandem or cascade reaction is also an effective approach for the rapid introduction of molecular complexity into a system since the number of steps requiring independent optimization is greatly reduced. With the aim of creating new synthetic strategies to efficiently gain access to stereochemically complex small molecules, we envisioned the use of short iterative protocols to prepare reactive oligomers to which a diverse range of cascade cyclization processes could be applied.
In an attempt to minimize reaction optimization and chromatographic purification steps during the development of our small molecule precursors, we first developed an iterative synthesis based on a conjugate addition/reduction sequence that has allowed us to access a diverse series of oligo-vinyl ether intermediates. Significantly, both the addition and reduction steps proceed in near-quantitative yield, and reaction co-products can be removed without column chromatography. At the same time, most of our vinyl ether intermediates are stable to silica gel, and so analytically pure samples can be prepared when desired. Except for when very sterically demanding substrates are employed as electrophiles, the intermediates are isolated as single geometrical isomers. We also developed an improved synthesis of a previously intractable class of alkynoate starting materials (4-aryl-2-butynoates) to ensure a diverse range of easily accessible monomeric building blocks were available for our use.
With this effective iterative route in hand, we have several interesting small molecule targets at our disposal. We first applied our iterative route to synthesize oxygen-containing analogues of juvenile hormone III. These mono- and bis-vinyl ethers are currently undergoing biological testing (in collaboration with Dr. Steve Perlman and Dr. Michael Horst), and early results show promise as ecologically degradable insect control agents.
We also developed an unprecedented 6-endo/5-exo radical cascade reaction across bis-vinyl ethers which proceeds in good yield, high diastereoselectivity, and excellent regiochemical control. This reaction represents the first cascading radical cyclization ever reported for a bis-vinyl ether system and validates our iterative approach to molecular complexity.Graduate
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YANG, HSUAN, and 楊璿. "Nickel-CDC Catalyzed Kumada Cross-Coupling of Aryl Methyl Ethers with Grignard Reagents via C−O Bond Cleavage." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/9952t6.
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碩士國立中正大學
化學暨生物化學研究所
106
As the second largest renewable energy source in the world, how lignin can be effectively transformed into higher economic crops is the goal pursued by modern scientists. Among them, the functionalization of carbon and oxygen bonds to convert lignin to other compounds is a common method at present. However, the problem is that compared to common carbon and halogen bonds, the higher bond energy of carbon and oxygen bonds leads to less dissociation, so the use of organometallic catalysis can lower the activation energy of the reaction and thus facilitate the reaction, resulting in a more rapid rate of conversion. A common method is to use a nickel metal complex, which is catalyzed by a strong electron-donor ligand, so that the C–O bond is more easily oxidized and the functionalization reaction is completed. We utilized nickel and Grignard reagent to performed catalytic C–O bond cleavage. The inert C–O bond could be cleaved by a new type of nickel-catalyzed cross-coupling reaction with the assistance of Grignard reagents with an electron-rich carbodicarbene ligand synthesized by our laboratory. The scope of substrates, application and proposed mechanism of this reaction will be reported in this work.
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GEMECH, MENKIR MENGISTU, and 門吉書. "Computational and theoretical studies on the mechanisms of metal-catalyzed cycloisomerization and rearrangement reactions of aryl propargyl ethers, o-propargylbiaryls and 2/3-allenylindoles." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/753jw3.
Full textAbstract:
博士國立中正大學
化學暨生物化學研究所
106
This thesis contains seven chapters and the first chapter introduces homogeneous metal-catalyzed cycloisomerization and the importance of density functional theory (DFT) calculations in understanding the mechanism of homogeneous catalysis. In chapters 2 and 3, the mechanisms for the cesium fluoride-mediated Claisen rearrangement and the indium-catalyzed intramolecular hydroarylation of phenyl propargyl ether were investigated by means of DFT method. The calculation results indicate that CsF-mediated Claisen rearrangement of phenyl propargyl ether involves [3,3]-sigmatropic rearrangement followed by deprotonation of -allenylketone and nucleophilic cyclization to offer 2-methylbenzofuran. On the other hand, the computed results revealed that the indium-catalyzed intramolecular hydroarylation of phenyl propargyl ether proceeds through initial -coordination of the propargyl moiety to indium, which triggers nucleophilic attack of the phenyl ring via 6-endo-dig cyclization pathway in a Friedel-Crafts type mechanism leading to 2H-chromene. In the case of substituted aryl propargyl ethers, a methoxy group on the benzene ring lowers the activation barrier compared to that of the unsubstituted precursor for both CsF- and indium-catalyzed reactions. In chapter 4, a theoretical investigation of the mechanism and regioselectivity of the InCl3- and Au(I)-catalyzed cycloisomerization of o-propargylbiphenyl as well as the InCl3-catalyzed cycloisomerization of o-allenylbiphenyl has been carried out with the aid of DFT calculations. The calculation results reveal that the Au(I)-catalyzed cycloisomerization of o-propargylbiphenyl occurs exclusively via 6-exo-dig cyclization in a Friedel-Crafts-type mechanism. The results also indicate that the 6-exo-dig cyclization is highly favored over the 7-endo-dig cyclization with InCl3 catalyst, while the mechanism via allene intermediate is less likely. The feasibility of the InCl3-catalyzed cycloisomerization of o-propargylbiphenyl depends on the nature of a substituent on the phenyl ring and/or in the propargyl moiety. It is found that the cycloisomerization of electron-deficient o-propargylbiaryl as well as unfunctionalized biaryl bearing alkyl group in the propargyl moiety may not be feasible. In chapter 5, the mechanisms and selectivity of PtCl2- and AuCl-catalyzed cyclizations of indolyl allenols as well as PtCl2- and InCl3-catalyzed cyclization of biaryl propargyl alcohol were analyzed by means of DFT calculations to gain deeper insights into the reaction mechanisms and the different reactivity of Pt and In catalysts. By performing an exhaustive search on the potential energy surface, we found that PtCl2- and AuCl-catalyzed cyclizations of indolyl allenols involve 6-endo-trig cyclization followed by water cluster-assisted elimination of H2O, and the generation of product-catalyst complex occurs by in situ-generated H2O-assisted deprotonation/proto-demetalation sequence for Pt-catalysis and by 1,2-H shift for Au-catalysis. In contrast, PtCl2-catalyzed cyclization of biaryl propargyl alcohol proceeds through 6-exo-dig cyclization followed by direct hydrogen abstraction by hydroxyl group and 1,2-H shift processes to afford vinyphenanthrene, while the same reaction in the presence of InCl3 catalyst offers fluorene via concerted 5-exo-tet cyclization/aromatization. In chapter 6, the mechanism and regioselectivity of Au(I)-catalyzed cycloisomerization of 3-allenylmethylindole 1 were examined by means of DFT calculations. The calculated results ruled out pathway a that has been concluded as a feasible pathway in the original study for the cycloisomerization of substrate 1. In contrast, the calculated results suggest that 6-endo-trig cyclization in which the initial nucleophilic attack by C2 of the indole group towards the terminal carbon atom of the allene moiety leads to 6-membered ring fused indoly intermediate, which upon proton transfer provides the final product. Furthermore, the calculated results indicate that the regiochemistry of the initial nucleophilic attack of the indole core (i.e. C2 vs C3) is dependent upon the nature of substituent on the allene moiety and the phosphine ligand. The bistriflimide counterion is found to play crucial role as a proton shuttle by assisting proton transfer.
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Ramanathan, Mani, and 馬瑞門. "Synthetic studies towards the antimalarial fungal polyketide Codinaeopsin via an intramolecular Diels-Alder reaction and Efficient deprotection of benzyl ethers and aryl acetals using triphenylphosphine hydrobromide." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/pbp37w.
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博士國立中央大學
化學學系
101
Codinaeopsin (1) a new tryptophan derived polyketide was isolated in 2008 from an endophytic fungus collected in Costa Rica (Fig.1).1 The unique chemical structure of this target includes a densely substituted trans decalin carbocycle which is connected to an indole fragment through an unusual heterocyclic unit. Among the natural products found in this family, Codinaeopsin has the most substituted decalin unit with four methyl and a 1-methyl-propenyl groups attached to it. The unusual α-acyl-γ-hydroxy lactam (modified tetramic acid cores) with oxidized Cα position of tryptophan are often present in natural products from fungal sources. Codinaeopsin is having promising activity against plasmodium falciparum, the causative agent of most lethal form of malaria (IC50=2.33μg/mL) or 4.7μM. The structural complexity, together with the extraordinary biological profile, prompted us to choose this natural product as an ideal synthetic target. The synthetic plan relied on a late stage Lewis acid mediated intramolecular Diels-Alder (IMDA) reaction of E,E,E-triene with a suitable dienophile to yield the appropriately decorated decalin skeleton.The synthetic approach described here shares a number of key features, including rhodium catalyzed hydrogenation of commercially available mesitol, E-selective Horner-Wittig olefination protocol to construct the trisubstituted alkene and one pot TPAP oxidation/Wittig olefination of the sensitive polyene substrate. Syntheses of racemic exo and endo decalin cores of Codinaeopsin are accomplished via intramolecular Diels-Alder reaction under thermal and Lewis acidic conditions. The relative stereochemistry of these IMDA adducts were confirmed by NOE and single crystal X-ray techniques. In chapter 2, Triphenylphosphine hydrobromide is reported to cleave the benzyl ethers derived from 1o, 2o, alkyl and aryl alcohols to the corresponding alcohols and benzyltriphenylphosphonium bromide in good yields. The reaction is optimized both under microwave and conventional heating conditions using stoichiometric amount of triphenylphosphine hydrobromide. The mechanism of this reaction is also discussed. In chapter 3, Triphenylphosphine hydrobromide is reported to deprotect the aryl acetals and ketals to give the corresponding carbonyl compounds and alkyl phosphonium salts under convenient conditions (50 oC, microwave, 5 min. yields up to 90%). The reaction is compatible with acid sensitive functional groups and the mechanism is discussed through the substrates surveyed.
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Tai, Chun K'uan, and 戴俊寬. "Aryl Propargyl Ether Claisen Rearrangement: A DFT Study." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/89163924498616688220.
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碩士國立中正大學
化學暨生物化學研究所
101
The mechanism of Claisen rearrangement of aryl propargyl ether in gas phase and in solution phase has been investigated using DFT methods. The solution phase calculations were carried out using N, N-diethylaniline as a solvent in PCM model. The most possible routes involves [3, 3]-sigmatropic reaction followed by proton transfer in the first two steps and then deprotonation or [1, 5]-sigmatropic reaction. Finally, cyclization yield benzopyran or benzofuran derivatives. The [3, 3]-sigmatropic reaction is the rate-determining step for benzopyran and benzofuran with ΔG‡ value of 38.4kcal/mol and 37.9 kcal/mol at M06/6-31+G (d, p)//B3LYP/6-31+G (d) level in gas and solution phase, respectively, this computational results is excellently consists with the experimental value. More, it is found that the derivatives of aryl propargyl ether proceeded Claisen rearrangement, the rate-determining step might be changed from the first step (i.e. [3, 3]-sigmatropic reaction) to the second step (i.e. proton transfer step). According to the structure information and the NBO analysis, the substituent methyl groups on the aliphatic segment make the C3-O4 bond lengthen from 1.43 Å to 1.45 Å and C1-C10 bond shorten from 3.97 Å to 3.70 Å in the reaction center. The donor-acceptor NBO results suggest that the fewer methyl groups at C3- position result in the stabilization energy E(2) is higher and it means that the structure of transition state easily resonate to the reactant in the Claisen rearrangement reaction.
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Ramakrishna, T. "Synthesis, Metal Complexation And Catalytic Studies Of Poly(Ether Imine) And Poly(Benzyl Aryl Ether) Dendrimers." Thesis, 2004. http://etd.iisc.ernet.in/handle/2005/1311.
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Yang, Cheng-Juei, and 楊三睿. "Nonlinear Optical Polymers: polyurethane, polyimide and poly(aryl ether ketone)." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/06919805033993506299.
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碩士國立交通大學
應用化學研究所
85
Three types of new nonlinear optical polymers have been synthesized. The polymeric backbones are polyurethane, polyimide, and poly(arylether ketone), respectively. The NLO chromphores p-N,N-dialkyl(or diaryl)amono-[(5-tricyanovinyl)-2-thienylvinyl]benzene, which have substantial μβ, were covalently attached as side-chain pendant groups. The glass transition temperatures of the polymers are 174 ℃, 181℃, and 188 ℃. The onset of decomposition temperatures determined by TGA are 254℃, 406℃, and 444℃. The thermal stabilities of the NLO chromphores in the polymers were also studied by monitoring the change of the π─π* charge transfer absorption with temperature. The E-O coefficients of the NLO polymers are currently under inverstigation.
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Gong, Zhi-hao, and 龔智豪. "Synthesis and Characterization of Hyperbranched poly(aryl ether oxazole)s." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/43370143372889003735.
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碩士國立交通大學
應用化學系
87
Nucleophilic aromatic substitution polymerization of type monomers 4-[2-(4-Flourophenyl)-5-(4-hydroxyphenyl)-1,3-oxazol-4-yl]phenol and 3-[2-(4-fluorophenyl)-4-(3-hydroxyphenyl)-1,3-oxazol-5-yl]phenol,using K2CO3 as reagent and DMPU(1,3-Dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone) as solvent yielded hyperhranched(aryl ether oxazole)s PAEO(Ⅰ) and PAEO(Ⅱ),respectively. The reactivity of two aryl fluoride mononers used in nucleophilic aromatic substitution polymerization was explored utilizing 19F-NMR experiments. The 19F shifts reflect the reactivity of the individual monomers examined. The hyperbranched marcomolecules contain a large number of chain end function groups, and the physical properties of the polymers such as thermal property and solubility depend on the nature of the chain ends. The degree of branching of PAEO(Ⅰ) was determined with the help of model compounds using 1H-NMR and was found to be near 52% ,similar to what has been observed in other hyperbranched polymer systems.
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Tsai, Hung-Lung, and 蔡宏隆. "Synthesis and Properties of 1,2,4-Triazole Contained Poly(aryl ether)s." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/vuk42d.
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碩士國立臺北科技大學
化學工程研究所
95
We synthesized three 1,2,4-triazole based difluoro monomers containing azobenzene, carbazole, and triphenylamine, and azobenzene, respectively. The monomers were polymerized with various diols in polar aprotic solvent, 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU), in the presence of potassium carbonate yielding novel poly(aryl ether)s. The structures of monomers and polymers were confirmed by Elemental analyzer(EA), FT-IR and NMR. The optical properties were analyzed by UV-Vis and photoluminescence(PL) spectroscopy. The polymers exhibited UV-Vis absorption bands at 240-380nm in THF solution. Their photoluminescence spectra showed emission peaks around 320-520 nm in THF solution. The thermal properties of polymers were evaluated by TGA and DSC. The polymers exhibited glass-transition temperatures above 185 ℃, and the temperatures at 5% weight loss above 316 ℃ in nitrogen.
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Tseng, Yi Cheng, and 曾怡誠. "Physical Characterization of A Novel Poly(aryl ether ketone) and Related Topics." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/92882587035732497967.
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碩士國立成功大學
化學工程學系
86
Abstract The miscibility of two binary blend systems: poly(aryl ether ketone)(PAEK)/poly(ether imide)(PEI) and poly(aryl ether ketone) (PAEK)/poly(ether ether ketone)(PEEK) were investigated by using differential scanning calorimeter(DSC),optical and scanning electron microscopy(SEM), and Fourier-transform infrared spectrometer (FTIR). A single glass transition temperature (Tg) in the PAEK/PEI blends within the full range of composition was observed using DSC. The thermal transition breadth suggests that the scales of mixing are fine and uniform. A single Tg in the PAEK/PEEK blends within the full range of composition was confirmed by observing a single and sharp enthalpy relaxation peak . The shifting of the absorbance peaks of the carbonyl and ether groups in the PAEK/PEEK blends indicated that the special molecular affinity existed between these two functional groups. A negative value of the polymer-polymer interaction parameter,( ≒-1.15,was estimated from melting point depression. Phase homogeneity in this two binary blends was confirmed using SEM, indicating that the scales of homogeneity were beyond the resolution limits of SEM. Additionally, a rare miscibility of a ternary blend system formed by PAEK,PEEK and PEI was found .
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Zhuang, Chao-Yu, and 莊昭宇. "Synthesis and Properties of Poly(aryl ether)s Containing Triphenylamine and 1,3,4-Oxadiazole Moieties." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/j9dj86.
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碩士國立臺北科技大學
化學工程研究所
101
We synthesized three types of difluoro monomers containing triphenylamine and 1,3,4-oxadiazole. The monomers were polymerized with different bisphenols respectively to form novel poly( aryl ether )s by the nucleophilic displacement. According to the position of the fluoro atoms in the polymers, the thermal properties, optical properties and electrochemical properties of the polymers were investigated and discussed. The structures of monomers and polymers were confirmed by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy. The polymers showed excellent solubility in organic polar solvents such as NMP, DMF, DMSO, THF, and DCM. The polymers exhibited UV-vis maximum absorption bands about 280nm and 360nm, and showed PL maximum emission peaks at 458nm to 507nm in NMP solution. The glass transition temperatures ranged from 163 to 219°C, the temperature at 5% and 10% weight loss measured by TGA were in the range of 358 to 465°C and 392 to 486°C under nitrogen, respectively. The inherent viscosity of the poly( aryl ether )s were 0.10 ~ 1.26 dL/g. The electrochemical properties of the poly( aryl ether )s were investigated by cyclic voltammetry. The energy levels of the HOMO and LUMO were respectively estimated as -5.54 ~ -5.42 eV and -2.52 ~ -2.25 eV, respectively, calculated from the oxidation potentials and onset absorption wavelengths of the UV-vis spectra.
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Liu, Chan-Hua, and 劉展華. "Synthesis and characterization of low-dielectric poly(aryl ether) derivatives for high-frequency communication." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/16349877386075356506.
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碩士國立中興大學
化學工程學系所
103
To prepare materials with low dielectric constant, three synthetic approaches were performed by modifying the phenol moiety of phosphinated poly(aryl ether), P1. First, the phenol moiety of P1 was esterified with acetic anhydride. The product was cured with various commercial epoxy resins by the active ester moiety. The polarity of thermosets were decreased so that the dielectric constant of materials were decreased. But the thermal properties were also decreased. The esterification of P1 was performed with methacrylic anhydride in the second approach. The product was also cured with various commercial epoxy resins by the active ester moiety. Furthermore, the methacrylic moiety would crosslink by the curing procedure. The dielectric constant of thermosets were reduced without sacrificing too much in glass transition temperature (Tg). The phenol moiety of P1 was also modified by 4-chloromethylstyrene in this research to form a polymer with styrene-type terminals. The self-polymerization of this product was carried out by thermal curing. Thermoset products exhibits the best thermal and dielectric properties.