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Dissertations / Theses on the topic 'Aromatic Substitution'
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1
Martyn, R. J. "Ipso aromatic substitution." Thesis, University of Canterbury. Chemistry, 1985. http://hdl.handle.net/10092/7318.
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In the first part of this thesis the conformation and stereochemistry of a number of polychlorocyclohex-3-enones, formed by the reaction of chlorine in acetic acid and hydrochloric acid with polysubstituted phenols (or anilines), are discussed. Those polychlorocyclohex-3-enones with the H(Cl)CS or the Me(Cl)CS structural features were shown to exist in a twist-boat conformation with the CS-Cl bond in the flagpole orientation. In contrast, two polychlorocyclohex-3-enones with gem-dichloro substituents at C5, were shown to be conformationally mobile in solution. The alicyclic ring of two 4,4,5-trichlorocyclohex-2-enones were also shown to exist in twist-boat conformations, but with the CS-Cl bond in the equatorial orientation. A satisfactory correlation between the ¹H n.m.r. and infrared spectroscopic data and the known structures in the solid state indicates that these polychlorocyclohex-3-enones and polychlorocyclohex-2-enones adopt conformations in solution close to those observed in the solid state.
Extensive use of single-crystal X-ray structure analysis was made in the above structural studies; some thirteen structure analyses are reported in this thesis.
In the second part of this thesis are discussed the reactions of polysubstituted 2-methylphenols with chlorine in carbon tetrachloride in the presence of pyridine to give
6-chloro-6-methylcyclohexa-2,4-dienones. These 6-chloro-6-methylcyclohexa-2,4-dienones arise from ipso chlorine attack on the phenol ortho to the hydroxy function. It was shown that attack ipso to a methyl group occurred in preference to attack ipso to a chlorine atom. Where both ortho positions of the phenolic substrate are methyl substituted, the site of ipso chlorine attack is affected by the meta substituents.
In the third part of this thesis the additions of chlorine to 6-chloro-6-methylcyclohexa-2,4-dienones to give polychlorocyclohex-3-enones and polychlorocyclohex-2-enones are discussed. These addition reactions proceed by three distinct reaction mechanisms, 2,3-, 4,5- and 2,5-chlorine addition. The 2,3-chlorine addition reaction was shown to be powerfully acid-catalysed. In contrast, the 4,5- and 2,5-chlorine additions were shown to be only mildly acid-catalysed. Reaction mechanisms which accommodate these observations are discussed.
Finally, the formation of an acyclic pentachloro hex-3-enoic acid by the chlorination of 4-chloro-2-methyl-6-nitrophenol (130) in acetic acid and hydrochloric acid is described and a probable mode of formation suggested.
2
Kennedy, R. J. "Copper-promoted nucleophilic aromatic substitution." Thesis, University of Kent, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355148.
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Hartley, Joseph P. "Indium catalysed electrophilic aromatic substitution." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760785.
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Rodriguez, Medina Inmaculada Concepcion. "Studies on oxidative aromatic substitution." Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390923.
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Clough, Robert Steven. "The synthesis of aromatic polyethers by aromatic nucleophilic substitution." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1057072167.
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Nguyen, Quang. "Reinventing Aromatic Substitution: A Novel Look." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1292.
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Electrophilic aromatic substitution (EAS) and directed ortho-metalation (DoM) involve the direct substitution of an arene hydrogen. A major drawback involving EAS is the necessity for harsh forcing conditions for the reaction to proceed. Catalysts such as Lewis acids FeBr3 and AICI3 for the introduction of halogens and acyl groups, respectively, are each highly toxic and corrosive. Textbook preparations of aryl iodides classicaly involved the use of iodine and nitric acid. This approach affords only modest yields and does not provide regiospecific substitution of most substituted aromatics because most contain ortho/para directors which afford mixtures of isomers. The novelty of our procedure for the synthesis of the iodinated aromatics is twofold in that regiospecific para-iodination is observed and hydrocarbon media are utilized. Hydrocarbon media are less hazardous and greener than media used for halogenations reported in literature. This procedure always yields derivatives regiospecifically substituted para to an electron donating substituent. Moreover, this method eliminates the need to use hazardous oxidative catalysts. DoM is a reaction regiospecifically substitute an arene hydrogen at the ortho position. The media used in DoM reactions are less hazardous than those required for a variety of EAS reactions. The only problem for this reaction is use of extremely strong bases, alkyllithium reagents, which are known to be air and water sensitive. However, the DoM reaction does eliminate the need to separate ortho/para isomer mixtures so that only a single product is generated. The metalation yields predominantly products regiospecifically substituted ortho-to the direcing metalating group (DMG). With our deficiency catalysis concept and subsequent purificaion methods, relatively pure ortho-lithiated intermediates have been prepared. The study of catalysts/promoters on the derivatization of these intermediates is anticipated to be extremely insightful. For this study, we have shown that highly selective, efficient ortho-lithiation can be achieved by deficiency catalysis utilizing n-BuLi as the only strong metalating base.
7
Murphy, Nicholas Patrick. "Radical aromatic cyclisation and substitution reactions." Thesis, University of Warwick, 2008. http://wrap.warwick.ac.uk/2286/.
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This dissertation is divided into five chapters. Chapter One consists of an introduction to radical cyclisation and rearrangement reactions. Chapter Two investigates the reactions of substituted arylsulfonamides 278a-l with copper bromide and an amine ligand-TPA. This reaction involves an alkyl radical generated from the copper (I) bromide/TPA complex, which can then undergo a 1,5- ipso attack onto the sulfonamide leading to a cyclohexadienyl radical intermediate. Re-aromatisation and extrusion of sulfur dioxide leads to an amidyl radical intermediate. This can undergo either cyclisation back onto the aromatic ring to give the 6-substituted oxindole 336, or reduction from H-atom abstraction by the solvent leading to rearranged amides. A minor product identified as a 5-substituted oxindole 333 may be formed from direct radical cyclisation onto the sulfonamide followed by extrusion of sulfur dioxide. An unambiguous synthesis of 333 was obtained through the Stollé method in order to rigorously identify this product. For completion, the rearranged amide 280e was also unambiguously synthesised from known literature sources. It has been shown that the selectivity towards either rearrangement or cyclisation is dependent upon the solvent used and temperature. For example, toluene induces excellent selectivity towards cyclisation (to furnish oxindoles), while using dichloromethane (DCM) induces a greater selectivity towards rearranged amides. Chapter Three explores the effects of varying the alkyl chain length on the nitrogen atom on selectivity, while keeping both the aryl group and initiator the same. It has been shown that selectivity towards the rearrangement (or decrease in cyclisation) occurred when the alkyl chain was increased from N-butyl to N-dodecyl. In addition a similar solvent effect on selectivity was observed as discussed in Chapter 3, notably relatively more rearranged amide was produced with DCM and oxindoles with toluene. Chapter four involves investigating the copper-mediated radical cyclisation of haloamides to give oxindoles directly. The final chapter consists of the experimental.
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McMurdo, J. "Electrophilic aromatic substitution using methoxyacetyl chloride." Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302997.
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Liljenberg, Magnus. "Quantum Chemical Studies of Aromatic Substitution Reactions." Doctoral thesis, KTH, Tillämpad fysikalisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206964.
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In this thesis, density functional theory (DFT) is used to investigate the mechanisms and reactivities of electrophilic and nucleophilic aromatic substitution reactions (SEAr and SNAr respectively). For SEAr, the σ-complex intermediate is preceded by one (halogenation) or two (nitration) π-complex intermediates. Whereas the rate-determining transition state (TS) for nitration resembles the second π-complex, the corresponding chlorination TS is much closer to the σ-complex. The last step, the expulsion of the proton, is modeled with an explicit solvent molecule in combination with PCM and confirmed to be a nearly barrierless process for nitration/chlorination and involves a substantial energy barrier for iodination. It is also shown for nitration that the gas phase structures and energetics are very different from those in polar solvent. The potential energy surface for SNAr reactions differs greatly depending on leaving group; the σ-complex intermediate exist for F-/HF, but for Cl-/HCl or Br-/HBr the calculations indicate a concerted mechanism. These mechanistic results form a basis for the investigations of predictive reactivity models for aromatic substitution reactions. For SEAr reactions, the free energy of the rate-determining TS reproduces both local (regioselectivity) and global reactivity (substrate selectivity) with good to excellent accuracy. For SNAr reactions good accuracies are obtained for Cl-/HCl or Br-/HBr as leaving group, using TS structures representing a one-step concerted mechanism. The σ-complex intermediate can be used as a reactivity indicator for the TS energy, and for SEAr the accuracy of this method varies in a way that can be rationalized with the Hammond postulate. It is more accurate the later the rate-determining TS, that is the more deactivated the reaction. For SNAr reactions with F-/HF as leaving group, the same method gives excellent accuracy for both local and global reactivity irrespective of the degree of activation.<br><p>QC 20170510</p>
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Shen, Bin. "Studies on the nucleophilic aromatic 18 F-Fluorination from model compounds to aromatic amino acids /." [S.l. : s.n.], 2008.
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Jones, Craig Warren. "Nucleophilic aromatic substitution using supported copper(I) reagents." Thesis, University of York, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236184.
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Martin, Peter Arnold. "Nucleophilic substitution reactions of some polyhalogenated compounds." Thesis, Durham University, 1987. http://etheses.dur.ac.uk/6876/.
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Rate measurements for the reactions of a series of polyfluoro - and polychloro - pyridines with aniline and ammonia in 60/40 dioxan/water at 25ºC has shown that chlorine, when ortho and para to the position of attack, is activating with respect to fluorine, but at the position meta to the point of attack, chlorine and fluorine are virtually equivalent in their effect on reaction rate. The trifluoromethyl and nitrile groups were found to be activating relative to fluorine when ortho and para to the position of substitution and the nitrile group was thus found to be ortho/para directing. The ortho/para orienting effect of ring nitrogen was shown to be dominant in heterocyclic systems. It has been demonstrated for several different nucleophiles that nucleophilic attack in polyfluorinated heterocycles occurs so as to maximise the number of ortho and meta fluorines with fluorine being of little significance. Of the nucleophiles examined aniline and ammonia were found to be similar in their behaviour. Benzylamine however showed some propensity for substitution at positions ortho to ring nitrogen whilst N-methylaniline showed strong steric effects due to the N-methyl group, most notably when the heterocylic ring substituents were chlorine, trifluoromethyl and nitrile. Sodium was shown to have a 'salt effect' in the reactions of methoxide and phenoxide, and, a catalytic effect on the reactions of aniline affecting both the rate and position of substitution. The use of transition state, and molecular orbitals to explain the patterns of substitution is discussed. The trifluoromethylsilyl group was found to undergo nucleophilic attack at silicon and the series of mono, di and tri-fluoromethyl-pentafluorobenzenes were used to examine the concept of negative ion hyperconjugation.
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Roberts, S. D. "Regioselective electrophilic aromatic substitution reactions of naphthalene over solids." Thesis, Swansea University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638685.
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Chapter 1 highlights the many advantages of heterogeneous inorganic solids as catalysts, and summarises the various microporous and mesoporous solids that have been employed as catalysts. The synthesis and characterisation of the mesoporous materials that were used in the study are described. Chapter 2 focuses on the nitration of naphthalene. An introduction to nitration is given, and the results of nitration over a range of solids are presented. Unusual dinitronaphthalene product ratios were achieved over Al-MCM-41. Reactions catalysed by heteropoly acid immobilised within the pores of mesoporous materials are also described. Chapters 3 to 6 focus upon the alkylation of naphthalene. Emphasis is placed upon the importance of 2,6-dialkylnaphthalenes (2,6-DAN) as intermediates for the production of high performance engineering plastics, and why there is still significant room for improvement in both 2,6-DAN yield and selectivity. A molecular modelling study of 2,6- and 2,7- di-<I>tert</I>-butylnaphthalene (DTBN) highlighted the potential for achieving selectivity for the 2,6-over the 2,7-isomer. Zeolite H-Mordenite (HM) was the most selective catalyst for 2,6-DTBN, but showed poor activity. Efforts to increase both the 2,6-DTBN yield and selectivity over HM focused upon varying the reaction time; temperature; pressure; solvent; amount of alkylating agent, solvent, and catalyst; Si/Al ratio of the catalyst; and mode of addition. Optimisation resulted in a 60% yield of 2,6-DTBN with a 2,6/2,7 ratio of over 50. <I>tert</I>-Butylation reactions were achieved using mainly <I>tert</I>-butanol as the alkylating agent. The identification of by-products in the <I>tert-</I>butylation reaction has been attempted. Alkylation with other alkylating agents has been attempted, but selectivity for 2,6-DAN was inferior to that achieved in the <I>tert</I>-butylation reaction using <I>tert</I>-butanol.
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Earle, Martyn John. "New approaches to aromatic substitution reactions with carbon electrophiles." Thesis, Loughborough University, 1992. https://dspace.lboro.ac.uk/2134/33242.
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The thesis gives an account of work directed towards developing new reagent systems and methodology, with particular reference to the Friedel–Crafts and Vilsmeier–Haack reactions of aromatic and heteroaromatlc compounds. Ways of improving regioselectivity and developing a stereoselective Friedel–Crafts reaction have been investigated for a range of hetero-atom stabilised carbocations. This work is divided into two main areas: (1) the synthesis and use of pyrophosphoryl chloride in the Vilsmeier–Haack reaction, the results of this has shed new light on the mechanism of this classical reaction; (2) the control of the Friedel–Crafts reactions of bi-functional derivatives of glyoxylic acid and the use of chiral relays to induce diastereoselectivity.
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Cheong, C. L. "Substitution of polyhalogenoaromatic compounds by sterically hindered nucleophiles." Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376844.
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Duffy, Anne Merete. "Students' ways of understanding aromaticity and electrophilic aromatic substitution reactions." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3210647.
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Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2006.<br>Title from first page of PDF file (viewed June 7, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 280-290).
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Sherburn, Michael S. "Radicals and reactive rings." Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277935.
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Živković, Aleksandra. "RNA recognition by fluoro aromatic substituted nucleic acid analogues." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976480190.
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Moonga, B. S. "The kinetics of protiodecarbonylation reactions." Thesis, Brunel University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375474.
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Hagelin, Helena. "Palladium-catalyzed aromatic coupling and allylic substitution : an experimental and theoretical study /." Stockholm, 1999. http://www.lib.kth.se/abs99/hage0528.pdf.
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Donham, Leah L. "Gas-Phase Studies of Nucleophilic Substitution Reactions: Halogenating and Dehalogenating Aromatic Heterocycles." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5645.
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Halogenated heterocycles are common in pharmaceutical and natural products and there is a need to develop a better understanding of processes used to synthesize them. Although the halogenation of simple aromatic molecules is well understood, the mechanisms behind the halogenation of aromatic heterocycles have been more problematic to elucidate because multiple pathways are possible. Recently, new, radical-based mechanisms have been proposed for heterocycle halogenation. In this study, we examine and test the viability of possible nucleophilic substitution, SN2@X, mechanisms in the halogenation of anions derived from the deprotonation of aromatic heterocycles. All the experiments were done in a modified Thermo LCQ Plus equipped with ESI. The modifications allow a neutral reagent to be added to the helium buffer gas in the 3D ion trap. In this system, it is possible to monitor ion/molecule reactions over time periods up to 10 seconds. A variety of aromatic heterocyclic nucleophiles were chosen based on their inclusion of nitrogen and or sulfur as the heteroatoms. In addition to this, the halogenating molecules chosen included traditional halobenzenes and a new class of perfluorinated alkyl iodides. It was found that, experimentally, the SN2@X path is the likely mechanism in the halogenation of deprotonated heterocycles. With computational modeling, we have additional support for this substitution mechanism.
From this original study, two more studies were developed to look at the competing nucleophilic aromatic substitution reaction, SNAr. In the first of these studies, the focus was to look at how electron withdrawing substituents about an aromatic ring affect the ratio of SN2@X verses SNAr. As nucleophiles, 2-thiophenide and 5-thiazolide were used. The neutral reagents focus on trifluorobromobenzene derivatives along with pentafluorobromo- and -iodobenzene, and a two trifluoroiodobenzenes. What was found was that the ratio of the reactions depends on where the fluorines, or electron withdrawing substituents are in relation to the bromine or iodine on the ring. If the fluorines are in a close location to stabilize the resulting ionic product, SN2@X proceeds easily. However, the fluorines directly adjacent to the bromine or iodine also provide steric hinderance in the SNAr reaction.
In the final project, arylation and benzylation of bromopyridines was examined. The nucleophiles used were benzyl and phenyl anions as well as 5-thiazolide, and the neutral reagents were bromopyridines, with fluorines used as an electron withdrawing groups to help stabilize the transition state. In these experiments, steric hinderance highly affected the results between the phenyl and benzyl nucleophiles. With benzylic anions, the nucleophile is able to reach the aromatic ring with less steric interference and therefore can proceed with an SNAr reaction. In addition to this, with mono and difluorinated pyridine substrates, the nitrogen in the ring activated the ring yielding nucleophilic aromatic substitution losing fluoride rather than bromide in many cases.
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Seo, Sangwon. "Decarboxylative and direct functionalisations of aromatic compounds." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/decarboxylative-and-direct-functionalisations-of-aromatic-compounds(a9ddab1b-86a0-491e-a95b-d6b40c8bd7ab).html.
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Aromatic rings are privileged structures found in a diverse range of natural and synthetic compounds, thus synthetic methods for their functionalisations are important in organic synthesis. Despite significant advancements made, especially in the field of transition metal catalysis, work still continues for the development of milder, more efficient, and more atom economical reactions. We describe here our efforts towards the development of decarboxylative/direct C(aryl)–N and C(aryl)–C bond forming reactions using aromatic carboxylic acids and unfunctionalised arenes as cheap and widely available aromatic sources. The investigations into copper-catalysed and copper/palladium-catalysed intermolecular and copper/silver/palladium-catalysed intramolecular decarboxylative amination of aromatic carboxylic acids are reported. A new approach to decarboxylation of benzoic acids is also described. The reaction uses silver (I) catalyst and peroxydisulfate salt to generate aryl radicals via oxidative decarboxylation. The applications of this approach in intra- and intermolecular decarboxylative C–H arylation, and protodecarboxylation are described. Also described is the development of silver-catalysed trifluoromethylation of simple arenes and heteroarenes. The reaction proceeds via radical trifluoromethylation using trimethyl(trifluoromethyl)silane as the trifluoromethyl radical source. This method has been applied to the trifluoromethylation of complex agrochemical molecules, proving its synthetic utility in late-stage functionalisation. Furthermore, we describe the exploitation of trifluoroacetate derivatives as cheap trifluoromethylating reagents in copper-mediated decarboxylative C–H trifluoromethylation of 2-phenylpyridine.
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Telu, Sanjay. "AN INVESTIGATION OF OXIDATITIVE-SUBSTITUTION REACTIONS OF POLYCYCLIC AROMATIC HYDROCARBONS AND OTHER ELECTRON-RICH AROMATIC COMPOUNDS WITH HYPERVALENT IODINE REAGENTS." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1162492437.
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Mangion, Bernardino. "Extending and diverting the photochemical nucleophile-olefin combination, aromatic substitution (photo-NOCAS) reaction." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ66652.pdf.
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Shah, Parin Ajay. "Synthesis of terpenoids using a tandem cationic cascade cyclization-electrophilic aromatic substitution reaction." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6639.
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The terpene and terpenoid family of compounds is considered to be the largest group of natural products. These compounds not only display great diversity in their structural features but are also known to have a multitude of biological activities including but not limited to anti-bacterial, anti-cancer, anti-inflammatory, and anti-HIV properties. Remarkably, all the terpenoids formed in nature come from two molecules viz. isopentenyl pyrophosphate and its isomer, dimethylallyl pyrophosphate both consisting of just five carbons but assembled in many ways. Nature utilizes highly efficient, enzyme-mediated cascade reactions to transform simple linear molecules to more complex cyclic scaffolds.
Cascade or domino reactions are organic chemistry’s most powerful tools that, if executed correctly, mimic the extreme complexity of reactions occurring in nature. Our group has successfully utilized cationic cascade cyclization reactions, to prepare a large library of natural products along with their analogues. It was during the synthesis of one such natural product that it was discovered that a methoxymethyl (MOM) “protecting group” had been transferred within the same molecule. The optimization of this process not only allowed the synthesis of the desired tricyclic framework but also resulted in the liberated MOM group doing an EAS reaction which gave a new C-C bond. This transferred MOM group was further elaborated to different functional groups.
Use of the tandem reaction sequence in an attempt to prepare radulanin E has been described. Total syntheses of two chalcone-based analogous meroterpenoids have been successfully completed using the aforementioned sequence. An advanced intermediate for an entire new class of acridine-based schweinfurthins has been elaborated. The results will be discussed in detail.
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Serve', Brian J. "RUTHENIUM-MEDIATED NUCLEOPHILIC AROMATIC SUBSTITUTION OF HALOGENS ON BENZENE SYSTEMS: SYNTHESIS OF 1,3,5-TRIAMINOBENZENES." Case Western Reserve University School of Graduate Studies / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=case1152813193.
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Smith, Philip Henry Gaunt. "An investigation of the preparation of heterocyclic ring systems via intramolecular nucleophilic aromatic substitution." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/10458.
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Heterocyclic synthesis via processes involving single electron transfer, namely aromatic SRN1 ,reactions and copper metal- and cuprous halide-promoted substitutions have been investigated. The cyclisation step in all the 'syntheses is effected by an intramolecular aromatic nucelophilic substitution on a halogen atom which is ortho to the side chain bearing the nucleophilic species (generally an amide or thioamide moiety). The process of entrainment has been shown to be a valuable technique for effecting reactions performed' under SRN1 conditions. The mechanisms of, and the mechanistic relationships between the substitution processes, were investigated using well documented diagnostic probes for the SRN1 reaction and by conducting series of experiments on simple reaction systems whose behaviour under SRN1 conditions was already known. Ring systems prepared by the methods noted above include benzoxazoles, benzothiazoles, 1 ,3-benzothiazines, indoles and a tricyclic system. Attempts to prepare seven-membered heterocycles by increasing the length of the side chain proved unsuccessful. When the side chain bears a carbonyl function adjacent to the aromatic ring, an intramolecular SNAr reaction takes place and cyclisation of N-(2-haloaroyl)-N'-phenylthioureas occurred under mild conditions. Quinazolinones and a 1 ,3-benzothiazinone have been synthesised in this manner which appears to have little precedent in the chemical literature. The preparation of seven-membered heterocycles by an SNAr cyclisation proved fruitless extension of the side chain length by one carbon atom (effected by the preparation of an N-cinnamoyl-N-phenylthiourea) resulted in the cyclisation of the side chain. Reaction of certain of the N,N-disubstituted thioureas with copper (1) iodide results in the formation of 2-halobenzanilides by a novel rearrangement.
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Schory, David Henry. "Quantum Chemical Investigations of Nucleophilic Aromatic Substitution Reactions and Acid Dissociations of Aliphatic Carboxylic Acids." Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1253480264.
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Conde, Amanda Solis. "Synthesis of 5-methyl-3-phenyl-1,3,4-oxadiazol-2(3H)-one derivatives by electrophilic aromatic substitution." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1547584724393162.
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Gumus, Selahaddin. "Secondary Electronic and Solvent Effects on Regiospecific P-Bromination of Aromatic Systems." TopSCHOLAR®, 2018. https://digitalcommons.wku.edu/theses/3031.
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Bromoarenes are important aromatic building blocks that are commonly used to synthesize various functional compounds in pharmaceutical, agrochemical and related industries.1,2 This great demand for bromoarenes makes their preparation a widely studied area of synthetic organic chemistry. However, further understanding of the reactivity and regiochemistry of aromatic functionalization reactions is still necessary, as much about the secondary substitution and solvent effects remain unknown.
Resonance Theory is a widely used theoretical model to predict the regiospecifity and reactivity of the bromination of various aromatic compounds.3 The reactivity and regiospecificity of many substituted aromatic compounds is well explained using resonance theory.4 However, kinetic understanding of the p-bromination of halosubstituted aromatic compounds has not been investigated to the best of our knowledge.5,6In this thesis, the reactivity and regiospecifity of the p-bromination of activated secondary substituted aromatic compounds as well as media effects on the process will be discussed.
Synthesizing bromoarenes has been accomplished using many different experimental setups.7-11 N-bromosuccinimide is the most highly utilized electrophilic aromatic brominating agent. Many of the NBS- based aromatic bromination reactions have been reported using strong acids, strong bases, halogenated solvents, nonpolar solvents and polar solvents alike.12 The bromination reactions reported herein were performed using two different solvents, acetonitrile and acetone, to investigate the effects of solvent polarity on p-bromination. Although acetonitrile is one of the most commonly used solvents in the p-bromination of aromatic compounds, acetone has not been investigated.
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Leeming, S. W. "An investigation of those structural features necessary for copper-promoted nucleophilic substitution of aromatic halogen compounds by cyanide ion." Thesis, University of Kent, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373239.
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Modekrutti, Subrahmanyam. "UNHINDERED TRIANGULENE SALT PAIRS: SUBSTITUTION-DEPENDENT CONTACT ION PAIRING AND COMPLEX SOLVENT-SEPARATED DISCOTIC IONS IN SOLUTION." UKnowledge, 2015. http://uknowledge.uky.edu/chemistry_etds/50.
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This work sought to enforce aromatic interactions between compatible π-molecular orbital systems with ionic bonding. In this case the interacting partners are oppositely charged discotic triangulene derivatives. The observed properties of the heterodimeric ion-pairs likely arise due to a hypothetical synergy between electrostatics and π-interactions. The work presented here describes investigation of putative covalency arising from this hypothetical synergy in the electrostatics driven π-stacking. In order to probe this, various hypotheses were made and experiments were designed to test their validity. The results from the experiments show existence of contact ion-pairs and complex solvent-separated discotic ions in solution. The formation of complex ion-pairs arise due to the fact that the electrostatic interaction that brings the discotic ions together is strong, but does not neutralize when the contact is made. So, the dipole created by the monopoles in a dimeric contact ion-pair can attract ions at both termini forming oligomers. This process apparently continues towards highly aggregated states and then to nanometric species and at some point the material precipitates. The propensity to aggregate and form complex-ions limited our approach to the measurement of the energetics of the ion-pairing for two reasons: (1) the observables had a complex dependence on temperature, solvent, concentration and ionic strength; and (2) the mass in solution was undergoing kinetic evolution towards solid states. The turbidimetric effects arising due to aggregate formation further complicated the extraction of weak interactions between the ions and hence effects determination of ion-pairing constants.
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Brown, James John. "Organic reactivity and through-space effects." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/16244.
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Chapter 1 presents a mini-review of the prominent theoretical models which are employed in the prediction of the outcome of organic chemical reactions. The chapter covers the most widely used empirical and semi-empirical models, as well as some more recently developed models. Most have a common theme in that they were developed using electrophilic aromatic substitution as a model reaction. Chapter 2 describes the development of a predictive model based on the average local ionisation energy. The model is shown to be of use in predicting both the regioselectivity and relative reactivity of a wide range of molecules in electrophilic aromatic substitution reactions. An attempt is made to expand the model beyond electrophilic aromatic substitution to various other electrophilic reactions. Chapter 3 details the investigation into the predicted enhancement of reactivity of aromatic rings. Calculations of electrostatic surface potential surfaces show that the proximity of an electron rich atom to an aromatic ring increases the electron density of the ring. Analysis of the local ionisation energy surfaces of these molecules suggests that the reactivity of these rings towards electrophiles is also increased. Preliminary studies on model systems using NMR spectroscopy aim to determine whether this effect can be observed experimentally. Chapter 4 introduces a method for applying the average local ionisation energy to nucleophilic reactions. The ability of the model to predict the regiochemical outcome and relative reaction rates of various molecules is examined in a variety of reaction types, including nucleophilic aromatic substitution. Chapter 5 reports studies into the polarisation-induced cooperative effects that exist between hydrogen bonding groups. The cooperative effect has been measured quantitatively in some simple hydroxybenzene derivatives. An improved understanding of this effect, developed using small molecule models, should lead to an improved ability to predict the extent of this effect in larger systems.
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Wang, Yongfeng. "SYNTHESIS AND STRUCTURE-PROPERTY STUDIES OF ORGANIC MATERIALS CONTAINING FLUORINATED AND NON-FLUORINATED # SYSTEMS (SMALL MOLECULES AND POLYMERS)." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/593.
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Loline alkaloids (LA) are secondary metabolites produced by Epichloandamp;euml; (anamorph, Neotyphodium) grass endophytes. They are toxic and deterrent to a broad range of herbivorous insects but not to livestock. This protective bioactivity has spurred considerable research into the LA biosynthetic pathway. LOL, the gene cluster containing nine genes, is required for LA biosynthesis. The regulation of LOL genes during LA production in culture and in symbio is of interest. In this study, coordinate regulation between LOL gene expression and LA production level was investigated in both MM culture and symbiota. Results showed that expression of LOL genes in N. uncinatum MM culture were tightly correlated with each other (p andamp;lt; 0.0005), and all presented a significant temporal quadratic pattern during LA production. Gene expression started before LA were detectable, and increased while LA accumulated. The highest gene expression level was reached before the highest amounts of LA were detected, and gene expression level declined to a very low level after amounts of LA plateaued. Observations suggested that the hierarchical clusters based on the correlation coefficient could help to predict the roles of LOL genes in the LA pathway. In symbiota, coordinate coregulation of LOL gene expression with LA was found in E. festucae-meadow fescue inflorescences and stromata, whereby lower LOL gene expression corresponded with the lower LA level in stromata. In N. uncinatum (or N. siegelii)-meadow fescue vegetative tissues, dramatically higher LA levels were found in younger leaf tissue than in older leaf tissue, yet no evidence was found to relate this difference to LOL gene expression differences. Instead, substrate availability may regulate the LA level. In particular, asparagine was more than 10-fold higher in young leaf tissue than in old tissue, although proline was significantly lower in young tissue. Therefore, different regulatory mechanisms underlie LOL gene expression and LA production in different circumstances. The GUS activity of Pro-lolC2-GUS and Pro-lolA2-GUS in Neotyphodium species was almost undetectable in culture, though the activity could be detected in symbiota. The mRNA of GUS did not exhibit the same pattern as lolC2 or lolA2 in culture during LA production time course. A Pro-lolC2-cre transgene was expressed in complex medium, in which lolC2 mRNA was not detectable. These results suggest that proper regulation of LOL genes in culture or symbiota is dependent on the LOL cluster.
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Campbell, Joseph Patrick. "Toward Macromolecular Shape And Size Control: Novel Enantioselective Nitrations And Iterative Exponential Growth Methods For Polymer Synthesis." ScholarWorks @ UVM, 2019. https://scholarworks.uvm.edu/graddis/1090.
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Chirality is a key principle in organic chemistry. All chiral compounds are non-superimposable mirror images of each other and therefore lack an improper axis of rotation (Sn). These mirror images often have identical properties in an achiral environment, however when two chiral molecules interact, they produce different shapes and properties. Nature, to this extent takes advantage of this aspect through unique formation of shape defined biological macromolecules that are tailored to carry out various life processes. This level of shape control is only made possible because of natural chiral monomers such as amino acids or glycosides that make up such macromolecules. Under new methods such as Chirality Assisted Synthesis (CAS), shape and size-controlled polymers and macromolecules can be realized through the use of chiral monomers to make well defined macromolecules. Because chirality dictates shape, and shape defines function in reference to macromolecules, controlling the chirality of monomers, while concurrently dictating shape and size can lead to the potential of biomimetic methodologies and cage like structures.
Accessing shape defined monomers can be difficult especially when in reference to chiral compounds. The unique structure of enantiopure tribenzotriquinacenes show promise in the formation of well-defined cage like structures through utilization of CAS methodology. Synthesis of functionalized tribenzotriquinacenes along with development of an enantioselective electrophilic aromatic nitration method was attempted. Further exploration into the effectiveness of through-space enantioselective nitrations found a dependence on solvent temperature, and the auxiliary that is used. Synthetic difficulties, results, modifications and processes toward a generalized method are presented herein.
In addition, controlling the size of polymers has always been a difficult synthetic challenge. Overall selectivity toward one product over another is determined via a variety of chemical properties. However, the formation of sequence and size defined polymers are a prominent aspect of natural polymers. The size selective synthesis, of unique ABAB sequenced polymers was attempted using an iterative exponential growth method. The ability to scale up these processes and create monodisperse oligoethers is also presented and described herein.
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Herblot, Martin. "Synthèse et caractérisation de monomères téléchéliques précurseurs de polymères thermostables de type PEKK." Thesis, Rouen, INSA, 2014. http://www.theses.fr/2014ISAM0009.
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Le développement d'une nouvelle voie de synthèse de poly(éther cétone cétone),polymères thermostables, a été étudiée pour des matériaux composites à matrice thermoplastique obtenus par le procédé de moulage par injection de résine RTM. Pour cela,nous nous sommes orientés vers une polymérisation par couplage réactif entre des monomères difonctionnels et des agents de couplage. Neuf monomères X-EKKE-X avec différentes extrémités réactives ont été synthétisés par acylation de Friedel-Crafts ou substitution nucléophile aromatique puis caractérisés structurellement et thermiquement.Des essais de couplage à partir de monomères à extrémités COOH sur des bisoxazoline sont permis la synthèse en masse de quatre polymères, semi-cristallins ou amorphes, de faibles masses molaires. A travers l'étude du comportement thermique de molécules modèles, une fragilité thermique à partir de 250°C a été mise en évidence pour ces polymères et attribuée au pont ester-amide entre deux unités EKKE<br>A new synthetic route to poly(ether ketone ketone), thermostable and semi-crystalline polymers, has been studied towards composite materials with a thermoplastic matrix obtained by a resin transfer molding process (RTM). This original synthesis was conducted by coupling reactions between difunctionals monomers and coupling agents. Nine X-EKKE-X monomers with different reactive extremities have been synthesized by Friedel-Crafts acylation or nucleophilic aromatic substitution. Thermal and structural properties were thoroughly investigated. Four polymers with semi-crystalline or amorphous morphologies and low molecular weights were obtained by coupling reactions between monomers with COOH functional extremities and bisoxazolines. Through the study of the thermal behavior of models molecules, a thermal fragility was highlighted for these polymers from 250°C and assigned to the amide-ester bridge between two EKKE units
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Buquoi, John Quentin III. "Exploration Using Reaction Temperature to Tailor the Degree of Order in Micro-Block Copolymer Proton Exchange Membranes." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1274493418.
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Liu, Jiangqiong. "Kinetic Studies of 6-Halopurine Nucleoside in SNAr Reactions; 6-(Azolyl, Alkylthio and Fluoro)-purine Nucleosides as Substrates for Suzuki Reactions." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1821.pdf.
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Zheng, Huaiben. "Kinetics and mechanism of the hydrolysis and nucleophilic attachment/substitution of transition metal carbene complexes : kinetics of carbon proton transfers that lead to aromatic anions /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2006. http://uclibs.org/PID/11984.
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Nguyen, Thi Thanh Thuy. "Métallation chimiosélective des azobenzènes. Substitution nucléophile aromatique des acides naphtoïques en présence de ligands chiraux." Thesis, Le Mans, 2014. http://www.theses.fr/2014LEMA1035.
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Cette thèse comporte deux parties indépendantes. La première étude présente les premiers exemples de métallation de la structure azobenzène par les réactifs organométalliques polaires. Largement utilisés en tant que colorants, les azobenzènes trouvent actuellement de nombreuses applications dans le domaine des matériaux en raison de leur facile photoisomerisation E/Z. Il est montré que les bases organométalliques polaires classiques (n-BuLi, n-BuLi/TMEDA, n-BuLi/t-BuOK, TMPMgCl.LiCl, LDA) ne métallent pas l’azobenzène parent mais réduisent plutôt la liaison N=N. Cependant la métallation est possible avec le tétraméthylpipéridure de lithium si un groupement directeur de métallation tel que le méthoxy (OMe), diéthylamide (CONEt2) ou fluoro (F) est présent sur l’azobenzène. La réaction permet un accès original et direct à de nouveaux azobenzènes substitués. L’objectif de la deuxième partie est la synthèse de dérivés biaryliques chiraux en l’absence de métaux de transition (Pd, Ni…). Les biaryles chiraux sont présents dans de nombreuses molécules biologiquement actives et peuvent être utilisés comme ligands pour la catalyse asymétrique. La substitution nucléophile aromatique des acides naphtoïques en présence de ligands chiraux a été étudiée. Une optimisation fine des conditions réactionnelles (choix du solvant, température, structure du ligand…) a permis de préparer des 1,1’-binaphtalènes, 1,2’-binaphtalènes et phénylnaphtalènes avec de bons rendements et excès énantiomériques (jusqu’à 89% ee). La substitution nucléophile aromatique atroposélective de dérivés d’acides naphtoïques de type naphtyloxazolines et naphtoates est également décrite<br>This thesis is divided into two independant parts. The first part describes for the first time the chemoselective lithiation of azobenzenes. Azobenzenes derivatives are widely used as dyes and more recently have been applied to the preparation of photoresponsive molecular switches and materials by taking advantage of the N=N bond E/Z photoisomerization. Whereas standard polar organometallics (n-BuLi, n-BuLi/TMEDA, n-BuLi/t-BuOK, TMPMgCl.LiCl, LDA) reduce the N=N bond of the parent compound, aromatic HLi permutation occurs with LTMP when a suitable director of lithiation (OMe, CONEt2, F) is present in the benzene residue of the azo compound. The method allows a direct access to new substituted azobenzenes.Axially chiral biaryls, which are found in many biologically active natural products, are conventionally used as ligands for asymmetric catalysis. The purpose of the second part is to develop a new method for the preparation of axially chiral biaryls in the absence of transition metals (Pd, Ni…). To tackle that goal, nucleophilic aromatic substitution reactions on unprotected naphthoic acids were performed in the presence of chiral ligands. A careful optimization of the reaction parameters (choice of the solvent, temperature, structure of the ligand…) allowed to prepare chiral 1,1’- binaphthalenes 1,2’- binaphthalenes and phenylnaphthalenes in good yields and enantiomeric excesses (up to 89% ee). The atroposelective SNAr reaction of naphthyloxazoline and naphthoate derivatives was also reported
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Pichette, drapeau Martin. "Nouvelles méthodes de synthèse pour la formation de liaisons C(aryl)-hétéroatome et C(aryl)-C par réactions de substitution nucléophile aromatique et vinylique." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2015. http://www.theses.fr/2015ENCM0005.
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L'objectif central de notre thèse de doctorat visait l'utilisation d'halogénures d'aryles en tant qu'électrophiles dans des réactions de substitution nucléophile aromatique (SNAr). D'abord, nous avons cherché à former des liaisons C(aryl) hétéroatome par réaction entre des nucléophiles hétéroatomiques et des halogénures d'aryles substitués par des groupements électro-attracteurs. Les résultats de cette étude ont été comparés à des incohérences relevées dans la littérature et montrent que l'ordre de réactivité d'halogénures d'aryles communément accepté n'est pas toujours respecté. Un effet positif a été observé par l'ajout de 2,2,6,6-tétraméthyl-3,5-heptanedione pour l'arylation de phénols avec des halogénures d'aryles substitués par des groupements électro-donneurs, ce qui en fait la première méthode capable de générer des diaryléthers par cette voie réactionnelle sans ajout de catalyseurs métalliques. Ensuite, nous avons mis au point une réaction générale d'± arylation de cétones aromatiques avec des halogénures d'aryles dans des conditions réactionnelles douces. L'utilisation du t-BuOK, une base inorganique capable de transferts mono-électroniques, et de DMF comme additif permet la synthèse d'±-arylcétones avec d'excellents rendements. Cette méthode a été appliquée à la synthèse d'hétérocycles fusionnés et de (Z)-tamoxifène, des molécules montrant une activité biologique. Une étude mécanistique a montré que l'anion carbamoyle du DMF est impliqué dans une étape clé de transfert mono-électronique avec des halogénures d'aryles. Nous avons également appliqué cette méthode à la substitution nucléophile vinylique de ″-halostyrènes. Bien que des précédents de la littérature font état de mécanismes ioniques pour les réactions de ces substrats, nos résultats expérimentaux supportent un mécanisme radicalaire. Enfin, nous avons tenté de mettre au point le premier protocole permettant la synthèse de biaryles dissymétriques au départ d'halogénures d'aryles et de triarylbismuths(III) via une catalyse par des sels de cuivre. Malgré le fait que de nombreux ligands bidentates et tétradentates ont été testés, les faibles rendements obtenus font que les conditions réactionnelles demeurent à optimiser. Globalement, nous avons donc apporté une contribution en ce qui concerne la détermination de la frontière expérimentale entre la SNAr et la catalyse métallique, la fonctionnalisation en ± de cétones aromatiques et la synthèse de biaryles dissymétriques par réactions de couplages croisés de triarylbismuths catalysées au cuivre<br>The primary objective of our doctoral research was centered on the use of aryl halides as electrophiles for nucleophilic aromatic substitution (SNAr). First, we tried to create C(aryl)−heteroatom bonds by reacting heteroatom nucleophiles with aryl halides substituted by electron-withdrawing groups. The results of this study were compared with inconsistencies found in the literature and show that the expected order of reactivity of aryl halides is not always observed. A beneficial effect was observed by adding 2,2,6,6-tetramethylheptane-3,5-dione to the reaction of phenols and aryl halides substituted by electron-donating groups in what is the first method allowing the synthesis of diarylethers without added metal catalysts by this pathway. Second, we developed a general α-arylation reaction of aryl ketones with aryl halides under mild reaction conditions. Use of KOt-Bu, an inorganic base capable of single-electron transfer, and DMF as additive enables the synthesis of α-arylketones in excellent yields. This method was applied to the synthesis of fused heterocycles and (Z) tamoxifen, molecules possessing biological activity. A mechanistic study showed that the carbamoyl anion of DMF is involved in a single-electron transfer reaction with aryl halides as the key step of the mechanism. We next applied this method to the nucleophilic vinylic substitution of β-halogenostyrenes. While literature precedents suggest ionic mechanisms for reactions involving these substrates, we obtained experimental evidence suggesting a radical mechanism. Third, we tried to develop the first protocol enabling the copper-catalyzed synthesis of unsymmetrical biaryls starting from aryl halides and triarylbismuthanes(III). Although many bidentate and tetradentated ligands were tested, further optimization is required in order to develop a general method, as only low yields are obtained. Globally, we have contributed to the determination of the experimental frontier between SNAr and metallic catalysis, to the α-functionnalization of aryl ketones and to the synthesis of biaryls through copper-catalyzed cross-coupling reactions of triarylbismuths
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Fetters, Hannah. "Functionalized PEEK Analogues from 2,4- and 3,5- Difluorobenzophenone Derivatives." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1559497023409191.
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Dehbi, Oussama. "Synthèse de nouveaux dérivés pyridopyrimidiniques, imidazopyridiniques et imidazopyridaziniques : évaluation de leurs propriétés biologiques." Thesis, Orléans, 2012. http://www.theses.fr/2012ORLE2078/document.
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Les produits appartenant à la famille des pyridopyrimidines sont caractérisés par leur intense utilisation dans le domaine pharmacologique, ce qui a poussé différentes équipes de recherche, de par le monde, à les étudier chimiquement et biologiquement. Dans ce travail, nous nous sommes intéressés au groupe des pyridopyrimidines et, plus particulièrement, à l’isomère le moins décrit dans la littérature, à savoir les pyrido[3,2-d]pyrimidines. Les composés ciblés sont synthétisés à partir de la 2,7-dichloropyrido[3,2-d]pyrimidine, via des substitutions nucléophiles aromatiques et des couplages pallado-catalysés et ce, dans le but d’obtenir de puissants inhibiteurs de kinases. Ce but a été atteint puisqu’en effet plusieurs des molécules élaborées inhibent les kinases testées avec des concentrations de l’ordre du nanomolaire. Des résultats pharmacologiques aussi concluants nous ont amenés à étendre nos études à d’autres pyridopyrimidines, à savoir les pyrido[2,3-d]pyrimidines ainsi qu’à d’autres types de bicycles polyazotés, en l’occurrence les imidazo[1,2-a]pyridines et les imidazo[1,2-b]pyridazines<br>Products belonging to the pyridopyrimidine family are characterized by their intense use in pharmacology. The increase of interest for this heterocyclic scaffold prompted different research teams around the world to study their chemically and biologically properties. In this work, we are interested in the functionalization of pyridopyrimidines and, more specifically, of the less described regioisomer, namely pyrido[3,2-d]pyrimidines. The target compounds were synthesized from 2,7-dichloropyrido[3,2-d]pyrimidine via nucleophilic aromatic substitution and palladium-catalyzed couplings and, in order to obtain potent kinases inhibitors. Our goal has been achieved with several elaborate molecules. These bioactive compounds inhibit kinases such as Cyclin Dependant Kinases (CDK), Glycogen Synthase 3 (GSK3) or Dual specificity tYRosine-phosphorylation-regulated Kinase 1A (DYRK1A) in the nanomolar range. These biological targets are mainly involved in degenerative process or down syndrome. These pharmacological results led us to extend our studies to other pyridopyrimidines, namely pyrido[2,3-d]pyrimidines as well as other types of polynitrogenated bicycles, namely imidazo[1,2- a]pyridine and imidazo[1,2-b]pyridazine
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Labadi, Adnan Ghaleb Mohammed al. "Nucleophilic aromatic substitution by [18F]fluoride and its applications to the synthesis of model precursors for the multi-step synthesis of the PET-tracer 6-[18F]fluoro-L-DOPA." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980292638.
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Cook, Teresa L. "Developing Green One-Step Organic Reactions in the High Speed Ball Mill." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397736534.
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HADDAD-FAHED, OMAIMA. "Catalyse micellaire de reactions de substitution nucleophile aromatique comportant des reactifs electriquement charges." Paris 6, 1987. http://www.theses.fr/1987PA066419.
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Chan, Mary S. W. "Factors influencing the regiochemistry of nucleophilic addition to the radical cation of alkenes and dienes studied in the context of the photochemical nucleophile-olefin combination, aromatic substitution (photo-NOCAS) reaction." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ36574.pdf.
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Bielawski, Marcin. "Efficient and High-Yielding Routes to Diaryliodonium Salts." Licentiate thesis, Stockholm : Department of Organic Chemistry, Stockholm University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-7969.
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Le, Tin Thanh. "Métallation et substitution nucléophile aromatique des acides benzoïques non protégés : application à la synthèse totale de l’apogossypol." Thesis, Le Mans, 2011. http://www.theses.fr/2011LEMA1016/document.
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Dans le cadre d’un projet général concernant l’étude de la réactivité des acidesbenzoïques non protégés avec les organométalliques, la synthèse totale d’analoguesstructuraux de l’apogossypol mettant en jeu des réactions de métallation aromatique a étéétudiée ainsi que la réaction de substitution nucléophile aromatique des acides benzoïquesortho-fluorés et ortho-méthoxylés.Le gossypol, (1,1’,6,6’,7,7’-hexahydroxy-5,5’-di-iso-propyl-3,3’-diméthyl-2,2’-binaphtalène-8,8’-dicarboxaldéhyde), pigment principal des graines du cotonnier, existe sousla forme de deux atropoisomères et possède de multiples applications pharmaceutiques. Il estnotamment un inhibiteur efficace des protéines anti-apoptotiques de la famille Bcl-2. Legossypol déformylé ou apogossypol présente des propriétés similaires mais est plus stable,plus sélectif et moins toxique. Une méthode permettant de remplacer les groupes iso-propylesdu gossypol par des groupes structurellement proches a été mise au point. La stratégie retenuemet à profit les compétences du laboratoire dans le domaine des réactions de métallation etrepose sur la lithiation latérale de l’acide 4-hydroxy-6,7-diméthoxy-8-méthyl-2-naphtoïquepar le tétraméthylpipéridure de lithium. Divers dérivés 5,5’-didés-iso-propyl-5,5’-dialkylapogossypol racémiques ont été préparés selon cette méthode. La synthèse asymétriqued’analogues de l’apogossypol a également été étudiée et la voie de synthèse sélectionnéerepose sur le « concept lactone ». Un intermédiaire avancé de la synthèse, une lactonefonctionnalisée potentiellement réductible de façon asymétrique, a été préparée.La deuxième partie est consacrée à l’étude de la réaction de substitution nucléophilearomatique des acides benzoïques ortho-fluorés et ortho-méthoxylés (réaction SNArAB). Unerevue de la littérature des réactions de substitution nucléophile aromatique activée par lesesters est présentée. L’influence de substituants méthoxylés et halogénés (F, Cl, Br) sur lasélectivité SNAr/addition 1,2 a été évaluée. Il est montré que les acides 2-fluoro-6-halogénobenzoïques conduisent, par réaction avec les aryllithiens et les arylmagnésiens, auxproduits d’ipso-C2-substitution avec un excellent rendement et la réaction SNArAB permet unaccès efficace aux acides 3-halogéno-[1,1’-biphényl]-2-carboxyliques. Dans le cas de l’acide2,3-diméthoxybenzoïque, il a été découvert que la présence d’un substituant méthoxy enposition 3 permet de limiter la formation de cétone et le produit d’ipso-substitution est isoléavec un rendement correct<br>As part of a program directed toward the study of the reactivity of unprotected benzoicacids with polar organometallics, the total racemic synthesis of apogossypol analogues bymetalation reactions was studied as well as the aromatic nucleophilic substitution reaction ofortho-fluoro- and ortho-methoxybenzoic acids (SNArAB reaction).Gossypol (1,1’,6,6’,7,7’-hexahydroxy-5,5’-di-iso-propyl-3,3’-diméthyl-2,2’-binaphtalène-8,8’-dicarboxaldéhyde) which is the main pigment of cotton seed, displaysmultiple pharmacological applications. It is a potent anti-apoptotic Bcl-2 protein inhibitor.The racemic route developed herein allows the replacement of the iso-propyl groups byvirtually any alkyl groups, providing a series of 5,5’-dides-iso-propyl-5,5’-dialkylapogossypolderivatives. Lateral metalation of 4-hydroxy-6,7-dimethoxy-8-methyl-2-naphthoic acid withLTMP is the key step of the synthesis. Atroposelective synthesis of apogossypol analoguewas also examined. The strategy relies on the “lactone concept” and involves a functionalizedlactone as a key intermediateThe influence of halogen atoms (F, Cl, Br) and methoxy groups on the 1,2-addition/SNArAB selectivity was examined. Treatment of 2-fluoro-6-halobenzoic acids withorganolithiums or Grignard reagents gives ipso-substituted products in excellent yields. Themethod allows the efficient preparation of 3-halo-[1,1’-biphenyl]-2-carboxylic acids and doesnot require protection of the carboxylate. Interestingly, the presence of an additional methoxyin C3 reduces the nucleophilic addition of the organometallic species to the carboxylate and2,3-dimethoxybenzoic acid affords ipso-substituted products in good yields
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Chen, Zhongrui. "Azacalixphyrines : émergence d'une nouvelle famille de tétraazamacrocycles aromatiques." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4074.
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Les travaux de thèse présentés dans ce mémoire ont ciblé trois familles de molécules π-conjuguées et s’inscrivent plus particulièrement dans le développement de la chimie des amino-azacalixarènes et des dérivés de phénazine, et d’une nouvelle classe de tétraazamacrocycles aromatiques appelés « azacalixphyrine ». Ces composés étant émergents dans la littérature, nous avons volontairement porté nos efforts sur la synthèse et la compréhension de ces nouveaux systèmes π-conjugués afin d’élaborer de nouvelles voies de synthèse mais aussi, le cas échéant, d’établir des relations structure / propriétés. L’accès synthétique à ces composés est basé sur des réactions de substitutions nucléophiles aromatiques. De nouveaux outils moléculaires sont ainsi proposés pour différentes applications dans le domaine de l’énergie, des matériaux et/ou de la santé<br>The thesis work deals with three families of π-conjugated molecules and particularly focuses on amino-azacalixarenes and phenazine derivatives as well as a new class of aromatic tetraazamacrocycles named “azacalixphyrin”. Since these compounds are emerging in the literature, we have deliberately focused our efforts on their synthesis and on the physico-chemical studies of these new π-conjugated systems in order to, when it is appropriate, establish structure / properties relationships. The synthetic accesses to these compounds are mainly based on aromatic nucleophilic substitutions. All these derivatives are potentially new molecular tools for various applications in the fields of energy, materials and medicines