Dissertations / Theses on the topic 'Heterocycle'
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1
Qaddo, Akram. "Enantiospecific nitrogen heterocycle synthesis." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/15791/.
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Morley, Thomas James. "Sulfur mediated heterocycle synthesis." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613825.
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Sadig, Jessie E. R. "Palladium-catalysed heterocycle synthesis." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:c9608957-d215-4a15-87e3-5871c1391946.
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Chapter 1 is a literature review of selected palladium-catalysed aryl C-N and C-S bond forming reactions. The application of these reactions to the synthesis of heterocycles is also discussed. Chapter 2 highlights the importance of the benzimidazole motif and gives a brief discussion of the existing routes to this scaffold. The utility of N-(o-halophenyl)imidoyl chlorides and imidates as precursors to heterocycles is demonstrated in a palladium-catalysed reaction with N-nucleophiles to afford benzimidazole products. Chapter 3 provides a brief introduction to the synthesis of benzothiazoles and describes efforts towards the use of our established substrates for the preparation of these heterocycles. This is achieved via reaction of N-(o-chlorophenyl)imidoyl chlorides with a sulfur nucleophile in a metal-free process. Chapter 4 is a literature review of palladium-catalysed carbonylation chemistry with specific focus on aminocarbonylation and thiocarbonylation reactions of aryl halides. Heterocycle syntheses which employ such carbonylative methods are also discussed. Chapter 5 describes existing protocols for the synthesis of quinazolinones. A novel palladium-catalysed synthesis of these heterocycles from the reaction of our imidate substrates with an amine and carbon monoxide is described. This further demonstrates their utility as general heterocycle precursors
4
Wang, Yinli. "Development of A New Heterocycle Forming Reaction and Kinetic Resolution with N-Heterocyclic Carbenes." Kyoto University, 2018. http://hdl.handle.net/2433/232320.
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Foster, Radleigh. "Tandem reactions for nitrogen heterocycle syntheses." Thesis, University of Oxford, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.669897.
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Shirtcliff, Laura Donnell. "'Coarctate' cyclizations : applications to heterocycle synthesis /." view abstract or download file of text, 2006. http://proquest.umi.com/pqdweb?did=1188876631&sid=1&Fmt=2&clientId=11238&RQT=309&VName=PQD.
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Thesis (Ph. D.)--University of Oregon, 2006.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 336-357). Also available for download via the World Wide Web; free to University of Oregon users.
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Braunton, Alan James. "Tethered cycloaddition reactions for heterocycle synthesis." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407915.
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Tadd, Andrew. "Palladium and copper catalysed heterocycle synthesis." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504606.
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Brumwell, Julie E. "Heterocycle synthesis using free radical cyclisations." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357926.
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Ball, Catherine Jane. "Palladium- and copper-catalysed heterocycle synthesis." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:589b70fb-0823-4ccf-8b35-1883908f917d.
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A number of privileged starting materials based on aryl halide frameworks have emerged that allow access to a variety of different heterocyclic scaffolds through judicious choice of reaction conditions. This work describes efforts to develop and extend the utility of two of these general heterocycle precursors - ortho-(haloalkenyl)aryl halides A and α-(ortho-haloaryl) ketones B - in conjunction with cascade reactions involving the construction of key carbon-heteroatom bonds via palladium or copper catalysis. Chapter 1 entails an overview of the development of palladium- and copper-catalysed carbon-heteroatom bond forming processes. The application of these processes in heterocycle synthesis using ortho-(haloalkenyl)aryl halide and ortho-haloacetanilides/ α-(ortho-haloaryl) ketone precursors is also described. Chapter 2 focuses on the development of a two-step synthesis of cinnolines using ortho-(haloalkenyl)aryl halides via intermediate protected dihydrocinnoline derivatives C. Chapter 3 demonstrates how the inherent reactivity of protected dihydrocinnoline derivatives C can be harnessed to provide access to functionalised products. A brief target synthesis of a pharmaceutically-relevent cinnoline is also described. Chapter 4 details attempts to develop a novel synthesis of benzothiophenes D from both ortho-(haloalkenyl)aryl halide and α-(ortho-haloaryl) ketone precursors.
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Cartwright, Matthew William. "Highly functionalised fused heterocycle synthesis from fluoropyridines." Thesis, Durham University, 2006. http://etheses.dur.ac.uk/2622/.
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Current approaches to drug discovery tends to involve the rapid analogue synthesis and testing of small, focused libraries of low molecular weight, structurally similar "drug-like" molecules, often based around heterocyclic core scaffolds. If some desired activity is shown by a compound, elaboration can give higher activity and more favourable pharmiokinetic properties. As this "lead generation" stage of drug development has been identified as a major bottleneck in the drug pipeline process, there is a great demand for methodology detailing the synthesis of highly functionalised heterocyclic compounds. Our approach involves the sequential nucleophilic aromatic substitution of highly fluorinated pyridines, in an efficient and flexible manner, to furnish a range of novel, functionalised polycyclic systems.
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Holden, Catherine. "Transition metal-free arylation and heterocycle synthesis." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/transition-metalfree-arylation-and-heterocycle-synthesis(4ecff18c-6cf9-4dfe-a874-1d83601c94d3).html.
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Arenes are ubiquitous motifs in both naturally occurring and synthetic functional organic molecules. The investigation of metal-free methodology for the installation of these motifs is important for sustainable development and the discovery of new modes of reactivity. Chapter 1. The preparation of halogenated phenoxathin 10,10 dioxides was ascertained to proceed through fluoride-induced decomposition and subsequent recombination of two molecules of the o-trimethylsilyl(aryl) triflate aryne precursors. Chapter 2. A new mild and metal-free methodology for the transition metal-free preparation of 2-amino biaryls using the benzyne intermediate was established. This proceeds via a desulfonative Truce-Smiles rearrangement of an aryl anion in the key bond-forming step. Chapter 3. The electron-poor S-aryl sulfonamides developed in chapter 2 were explored as reagents for metal-free 1,1- and 1,2-carbonamination. Asymmetric catalysis was also investigated for the preparation of enantioenriched alpha,alpha-disubstituted aryl glycine derivatives. Chapter 4. Some organocatalytic methods for the vicarious nucleophilic substitution of hydrogen were investigated to expand the remit of this classical arylation mechanism.
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Visco, Michael David. "Chiral Silanediols Designed for Enantioselective Heterocycle Functionalization." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492438099945523.
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Swindlehurst, Marianne. "Ethoxyvinylarenes as versatile intermediates for heterocycle synthesis." Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/841208/.
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In the field of drug discovery, pyrrolopyridine moieties are often incorporated into bioactive molecules. This is due to their ability to form both pi-stacking and hydrogen bonding interactions when binding to target proteins. This project aimed to provide a robust and rapid method of synthesis that will provide access to substituted pyrrolopyridines. The work is based on a previously published method involving the synthesis of ethoxyvinyl(amino)arenes, by Suzuki reaction of halo-aminoarenes, followed by cyclisation. It was hoped this method would be advanced by applying alternative cyclisation reactions to the ethoxyvinyl(amino)arenes to give 3-substituted products in one step. In comparison with previous methods, this route would be inexpensive, robust and applicable to a wide range of substrates. It was also envisaged that alternative starting materials could be used to make it a more generalised method for the synthesis of bicyclic arenes. Work began with testing the reproducibility of the previously published method of synthesising the ethoxyvinyl(amino)arenes. This was done successfully, although a change in ligand (SPhos to RuPhos) proved beneficial, with seven different analogues being synthesised in yields ranging from 36% to 98%. This same reaction was attempted with halo-hydroxypyridines, with a novel route to furopyridines in mind, but with no success. The synthesis of non-commercially available halo-hydroxypyridines themselves also proved to be challenging with no material being isolated. Various methods were tested for the bromo-cyclisation of ethoxyvinyl(amino)arenes to 3-bromopyrrolopyridines. A two-step method using acid cyclisation followed by bromination was entirely successful. Two-step, one-pot and one-step methods both appeared to promote polymerisation/oligermisation. Success was achieved with a one-step method employing an acid additive but only on selected ethoxyvinyl(amino)arene isomers and with varying yields. The work was extended to the attempted synthesis of anti-malarial precursors using the bromo-pyrrolopyridine isomers as building blocks and converting them to alkyl-linked glutarimides. This led to the successful and novel synthesis of the reactants vinyl glutarimide and glutarimylethylborolane. However, successful conditions for their palladium catalysed cross coupling with the bromides were not found.
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SASSI, MAURO. "Heterocycle-based redox active, electrochromic organic materials." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2011. http://hdl.handle.net/10281/25393.
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ELECTROCHROMIC MATERIALS represent a special and intriguing class of redox active compounds, characterized by a drastic change in their optical properties
upon reduction or oxidation. Many aromatic organic molecules, monomeric
or polymeric, are electrochromic, and some of them can even outperform their
inorganic counterparts in some aspects. In particular, the ability to easily tune
the colour of the redox states, represent an invaluable asset of this class of compounds.
Among the many different organic electrochromic materials, those
possessing a highly transmissive colourless state have gained much attention
for their potential application in smart windows, self-darkening eyeglasses,
anti-glare car rearview mirrors, etc. Moreover, a neutral tint of the coloured
form is desired for these applications in order to avoid colour distortion.
This work develops a novel class of discrete and polymeric electrochromic materials
based on the violene structural motif. In particular, the class of diazinium
ethenes has been explored and the electrochromic properties of the derivatives
have been evaluated by electrochemical measures. These compounds
have shown to undergo a reversible two-electron transfer, accompanied by a
colourless −)−−*− coloured electrochromic behaviour with high contrast in the
450-550nm region.
The new violene discrete electrochromes were then incorporated in a poly(3,4-
ethylenedioxythiophene) (PEDOT) matrix, developing an hybrid multichromophoric
system that take advantage of the characteristics of both systems to
achieve a panchromatic absorption in the reduced state and a very high contrast
value. In particular, the incorporation of the violene electrochromes has been
obtained linking them, through a tether, to an EDOT moiety, and subsequently
polymerizing (chemically or electrochemically) themodifiedmonomers (ISOx).
The obtained polymers, poly(ISOx), display colourless highly transmissive oxidized
states and reduced states with an extended colour palette (violet-red,
purple and brown). Moreover, an impressive electrochromic contrast in the
visible region has been achieved, with calculated luminance variations as high
as 72%. This result represent a big improvement compared to the literature reported
52% for a system with comparable spectral characteristics.
In the last chapter, a novel and versatile synthon for EDOT derivatization,
exo-methylene-EDOT, is described and characterized along with some of its
derivatives. This compound readily react with alcohols under acid catalysis
to give Markovnikov addition products, and with thiols, in presence of radical
initiators or photochemically, to give sulfides (anti-Markovnikov products).
The latter reactivity proved to be very interesting for the extreme rapidity and
high conversions achieved. An EDOT derivative with a pendant trialkoxysilane
moiety has been prepared using 3-mercaptopropyltrimetoxysilane as thiol
counterpart. This compound was subsequently tested as reagent for the functionalization
of surfaces with EDOT moieties. An alternative approach, relying
on an in situ thiol-ene reaction between exo-methylene-EDOT and a thiol functionalized
surface, was also tested to achieve such functionalization. Both procedures
have demonstrated to provide the desired surface modification. This
kind of ultra thin films could find application as coupling layers for the deposition
of PEDOT-like polymers on metal oxides, solving the adhesion problems
that hamper the long-term operation of the devices.
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Pillai, Jayasheela. "Heterocycle synthesis by hydrogen atom transfer and cyclisation." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298644.
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Hadden, Mark. "Enamides and enaminones : versatile intermediates for heterocycle formation." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322956.
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Simpson, Mark Geoffrey. "Steroid and heterocycle-based macrocyclic N-Acyl hydrazones." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621549.
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Sandon, Nicolas. "New and efficient strategies in stereoselective heterocycle synthesis." Thesis, University of Sheffield, 2009. http://etheses.whiterose.ac.uk/15106/.
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This thesis describes the development and the application of three different [3+3] annelation strategies for the formation of functionalised piperidines. Initially, the scope of the [3+3] cycloaddition reaction of Pd-trimethylenemethane and aziridines towards functionalised piperidines was investigated for its application to silyl ether substituted aziridines. These substrates appeared to be very challenging, undergoing the cycloaddition only under very rigorous conditions. Since this methodology was not trivial to repeat, a two-step strategy was explored that involved the addition of a Grignard reagent to the aziridines followed by ringclosure to the corresponding piperidines. These two procedures were found to be enantiospecific, providing good routes for the synthesis of enantiopure piperidines. The functionalisation of the exo-alkene group of these piperidines was also investigated with particular regard to the reaction diastereoselectivity. A third [3+3] annelation reaction towards the synthesis of the piperidine core has also been employed, which invoked the addition of the Bilchi Grignard reagent to the enantiopure silyl ether substituted aziridine (R)-139 to provide the corresponding acetal 263 in good yield. Acid catalysed cyclisation of the acetal produced the corresponding enantiopure tetrahydropyridine 264. The last section of this work focused on the applicability of these methods for the synthesis of natural products and highlights our attempts towards the synthesis of quinolizidine alkaloid (-)217A.
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Majhail, Manjeet K. "Applications of rhodium-catalysed hydroacylation in heterocycle synthesis." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:0ac3e86d-e031-408b-b861-20740853bb0b.
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The work compiled in this thesis documents the development of new methodologies towards the synthesis of a range of N-containing heterocycles. These methods utilise intermolecular Rh(I)-catalysed hydroacylation of chelating aldehydes with alkynes and alkenes to install carbonyl groups, which are exploited in subsequent heterocycle forming cascades. Chapter 1 presents a literature review of the development of both intramolecular and intermolecular rhodium-catalysed hydroacylation, with the focus of different methods to suppress decarbonylation and promote constructive catalysis. A brief description of some precedented examples of hydroacylation in heterocycle synthesis is also included. Chapter 2 describes the optimisation studies for the hydroacylation of S-/N-chelating aldehydes with terminal and internal propargylic amines. The studies are largely focussed on achieving high regioselectivity for the linear gamma-amino enone product. The cyclisation of these gamma-amino enone adducts to form pyrrole rings is also described. Chapter 3 presents the de novo one-pot cascade synthesis of mono-, di- and tri- substituted pyrroles via a highly regioselective hydroacylation pathway. The pyrroles are exploited in further modifications to access fully substituted heteroaromatic systems or in a three-component coupling of aldehydes, propargylic amines and boronic acids or alkynes to access 'traceless' pyrrole rings. The one-pot cascade methodology is extended to the synthesis of dihydropyrroles, through the hydroacylation of allylic amines, which grants access to pyrrolidine rings via diastereoselective reductions. Chapter 4 details the initial investigations towards the development of rhodium- catalysed hydroacylation of ynamides with chelating aldehydes. This provides access to beta-amino enones in a regioselective manner. These hydroacylation products, which are known to be versatile building blocks, are subsequently exploited in the synthesis of five- and six-membered heterocycles via bi-nucleophilic additions. Chapter 5 discusses the conclusions of the research and the potential for further work. Chapter 6 compiles the experimental procedures and data.
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Dexter, Hannah. "Towards the synthesis of heterocycle containing natural products." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/40735/.
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Chapter 1 gives an introduction to ribosomally synthesised and post-translationally modified peptides. The different classes of this group of natural products are described. Examples of linear azol(in)e-containing peptides and cyanobactins are given, along with more detail about these classes of peptides and examples of their chemical synthesis. Chapter 2 explains the importance of the natural product goadsporin 64, along with the retrosynthesis and a review of methods to synthese oxazoles, thiazoles and dehydroalanines. The first total synthesis of goadsporin 64 is then reported, demonstrating the use of rhodium catalysis to construct the four oxazole rings. Synthesis of the N-terminal fragment 78 validated methods for incorporating the sensitive enamide functionality, and removal of the necessary protecting group. These methods were then applied to the full structure to complete the total synthesis. Chapter 3 describes work carried out towards the total synthesis of the wewakazole natural products, again using rhodium catalysis methodology. The structures of wewakazole A 65 and wewakazole B 66 share a largely peptidic fragment 267, differing only by the bis-oxazole fragments 266 and 268, allowing the synthesis of two natural products via three main fragments. Reported herein is the synthesis of the bis-oxazole fragments 266 and 268 of wewakazole A 65 and B 66.
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Alharthy, Rima D. "The synthesis of procyanidin B3 and heterocycle-linked oligonucleotides." Thesis, University of Nottingham, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.594244.
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The first section of this thesis describes the synthesis of procyanidin B3, a dimeric flavanoid consists of monomeric (+}-catechin and a member of the polyphenol family. A study of the leaving groups at C4 catechin together with Lewis acid activator effects on the formation of the interflavan hond formation was conducted. A range of electrophilic ethers was prepared via DDQ oxidation and a1coholic trapping (propanol, crotyl a1rohol and propargyl alcohol) at the C4 position of (+}-catechin. The Lewis acid-mediated nucleophilic C4 substitution of each of these ethers was examined and it was found that the propargyl ether was the best overall e1ectrophile. A range of Lewis acids were then examined as activators and it was found that BF3oOEt2 was the best in terms of both yield and stereochemical control at the C4 position. In our view, the strength of the nucleophiles used contributed mainly to the diastereoselectivity preference for the substitution reactions. This newly developed set of conditions was then used to prepare the natural product nutraceutical procyanidin B3 with high control of diastereoselectivity. To extend the versatility of this synthesis, a novel dimeric polyphenol analogue was synthesised utilising the optimum conditions used for the synthesis of pro cyanidin B3. The second section of this thesis is devoted to the synthesis of novel morpholino antisense oligonucleotides. Herein, the synthesis of amine and amide triazolelinked Morpholinos (TI.Morpholinos) using click copper-catalysed Huisgen [3 + 2] cycloaddition is illustrated. Replacing the charged phosphodiester backbone with a neutral, achiral 1.2.3-triazole linkage was chosen to improve the biostability in antisense applications. The synthesis of terminal alkyne morpholinos and examples of azide monomers required for the click chemistry was successfully achieved. The synthesis presented in this work tolerated a range of functionalities and was amenable to all nucleosides. The amine and amide TI.Morpholino oligonucleotides were constructed using the standard solid-phase DNA synthesis. Both the amine and amide TLMorpholinos formed were characterised by MALDITOF and HPLC experiments. The thermal stability of the amine and amide TI.Morpholinos relative to a standard DNA was assessed and it was found that the amine and amide triazole linkages stabilised the DNA duplex. It was concluded that these modifications enhanced the stability of the DNA duplex and consequently might contribute to the development of new candidates for the antisense applications
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Williams, Andrew John. "Cyclic sulfates and sulfamidimates for asymmetric N-heterocycle synthesis." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288585.
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Adero, Philip O. "Heterocycle Synthesis via Rhodium (II)-Catalyzed Azido Carbenoid Cyclization." Youngstown State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1348595887.
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Kureppadathu, Raman Sumesh. "Carbon monoxide/heterocycle copolymerisation : new catalysts and new biodegradable polymers." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066575.
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Certains polymères synthétiques biodégradables ont montré des propriétés physico-chimiques aussi intéressantes que celles des plastiques issus du pétrole. Cependant, leur coût élevé dû au prix des matières premières ainsi qu’au faible nombre de voies de synthèse efficaces empêchent leur rentabilité. Une des alternatives serait le développement de méthodes de production viables économiquement par l’utilisation de catalyseurs productifs et de voies de synthèses à économie d’atomes. Ce manuscrit rassemble les travaux effectués durant la thèse sur une série de catalyseurs organométalliques hautement actifs pour la synthèse du poly(lactide), de nouvelles stratégies catalytiques pour la production du poly(3-hydroxybutyrate) et la polymérisation à économie d’atomes d’α-aminoacide-N-carboxyanhydrides pour la production de poly(α-peptides)Many synthetic biodegradable polymers show competitive physical properties compared to petrochemically derived plastics. However, due to the low availability and high cost of renewable feed stocks or lack of efficient synthetic routes, their industrial production and successful commercial execution lacks economical feasibility. One way to improve the current situation is the implementation of cost efficient methods either by using productive catalysts or by atom-efficient synthetic methods. Here we report the discovery of a series of highly active organometallic catalysts for the synthesis of poly(lactide), new catalytic methodologies for the production of poly(3-hydroxybutyrate), and an atom-efficient polymerization of α-aminoacid-N-carboxyanhydrides to poly(α-peptides)
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Jaffar, Sami Khawar. "Optimizing selectivity in heterocycle C-H functionalization through computational design." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:47ef06ba-b309-40e0-bbec-0539daaa7dbe.
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This thesis describes the application of quantum chemical methods to understand Pdcatalyzed C-H activation of aromatic and heteroaromatic molecules, with a view to establishing the factors that enable predictions of site-selectivity to be made. The first chapter introduces palladium catalyzed C-C bond formation and the synthetic field of direct (C-H/C-X) and oxidative cross-couplings (C-H/C-H), the postulated mechanisms of C-H activation, and the theoretical background to the project. The focus of Chapter 2 is the mechanism and site-selectivity of Pd catalyzed direct arylation of N-methyl indole. The mechanism is shown to proceed via a concerted metalation deprotonation of N-methyl indole followed by transmetalation with PhB(OH)2. Importantly, this second step determines the C2 regioselectivity observed experimentally, and the key transition structure is stabilized through a p-polar bond between AcOH and the C2-C3 p system of indole. In Chapter 3 we apply DFT calculations to examine the mechanism of Pd catalyzed activation of N-methyl indole in an oxidative cross-coupling. Calculations predict the mechanism to proceed via initial C-H activation of the indole followed by C-H activation of benzene. Concerted metalation deprotonation is favoured, and assisted by coordinating solvent molecules. Alternative mechanisms, previously postulated in the literature, are calculated and do not support observed experimental results. We extend our examination into the C-H activation and oxidative arylation of N-acetyl indole by investigating a co-catalyst Pd/Cu system in Chapter 4. Calculations demonstrate that a Pd-Cu dimer is energetically viable and leads to initial cleavage at C3. The regioselectivity of the mechanism is determined through the subsequent C-H activation of benzene and completed with a facile reductive elimination step. In Chapter 5 we apply a combination of DFT and kinetic modelling on the trifluoroacetic acid (TFA) tuned homocoupling of benzene and the heterocoupling of benzene and anisole. Concentration terms are applied with the implementation of transition state theory to develop kinetic models. Various catalytic models are investigated to show that Pd(OTFA)2, formed at high concentrations of TFA, favours homocoupling, while at lower TFA concentrations the catalytic species will be Pd(OAc)2-TFA which favours heterocoupling. Finally, Chapter 6 presents DFT studies on the Pd-catalyzed homocoupling and chemoselectivity of p-xylene. Pd(OTFA)2 is computed to display greater activity than Pd(OAc)2 in oxidative C-H cross coupling. Benzylic (sp3) C-H activation of p-xylene is computed to be relatively difficult compared with sp2 activation, but can nonetheless occur via an eight membered intermolecular deprotonation transition state.
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Picker, Jesse L. "Routes to N-Heterocycle Functionalized Poly(arylene ether sulfone)s." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1409597075.
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Henry, Christopher Edwin. "Phosphine-catalysis of allenoates mechanism, heterocycle synthesis, and asymmetric catalysis /." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1779690221&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Ghose, S. "Cycloaddition reactions of nitroalkenes." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384381.
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Wagland, A. M. "The application of the Diels-Alder reaction in the synthesis of some nitrogen heterocycles." Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377952.
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Young, Brian. "Synthesis of Aromatic Heterocycles via Pericyclic and Coarctate Cyclizations." Thesis, University of Oregon, 2013. http://hdl.handle.net/1794/13260.
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Highly conjugated, extended heterocycles are recognized as important materials for use in electronic applications, and therefore the synthesis and characterization of new molecules of this type are necessary. One method of forming extended heterocycles relies on the dual cyclizations of the hetero-ene-ene-yne motif. By controlling the reaction conditions, these systems can be made to selectively undergo either a pericyclic reaction to form a cinnoline or a coarctate cyclization to form an isoindazole. The ability of the hetero-ene-ene-yne motif to produce two different heterocycles with distinct properties makes it an attractive system to study. Another method of forming extended heterocycles with tunable properties is by fusing aromatic hydrocarbons with aromatic heterocycles such as thiophene.
Chapter I introduces the coarctate reaction and gives an overview of the Haley lab's work in this area. Chapter II explores the dual cyclizations of a phenanthrene-based system. In Chapter III an anthraquinone-based cyclization precursor is used to make diazaheterocycle analogs of tetracene. In Chapter IV isoindazoles were joined by an ethynyl linker to either phenyltriazenes and phenyldiazenes to yield molecules that could undergo both coarctate ring-forming and coarcate ring-opening reactions. Chapter V presents the synthesis and characterization of a series of indacenedithiophenes. Chapter VI advances the synthetic methodology of making larger heteroacenes by presenting work toward heterocyclic pentacene analogs.
This dissertation includes both previously published and unpublished co-authored material.10000-01-01
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Counceller, Carla Marie. "Development of Novel Methodologies for the Synthesis and Functionalization of Nitrogen Heterocycles." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275047798.
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MOUTOU, JEAN-LUC. "Synthese et interet pharmacologique d'imidazo (1,2-x) azines diversement fonctionnalisees en position 3." Strasbourg 1, 1993. http://www.theses.fr/1993STR15095.
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Barnes, Samuel. "Synthesis of 2,4-Disubstituted Pyrimidines of Possible Biological Interest." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/chemistry_theses/10.
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The synthesis of 2,4-disubstituted pyrimidine derivatives is described. The synthetic route involved the addition reaction of lithiated intermediates, mostly heterocycles, to position 4 of 2-chloropyrimidine to give a dihydropyrimidine intermediate which was oxidized back to a pyrimidine. This was followed by nucleophilic aromatic substitution with various amines of the chlorine in the position 2. A number of compounds were prepared which showed binding towards various serotonin receptors in preliminary biological evaluation.
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Stainforth, Nikki. "The catalytic generation and trapping of chiral enolates : enantioselective heterocycle synthesis." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497102.
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Hasan, Syed. "Synthesis of a peptide nucleic acid oligomer of a Janus heterocycle." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45751.
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Noble, A. "Investigation into the use of 1,2-diamines in fused heterocycle synthesis." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1346443/.
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The introductory chapter of this thesis gives a brief outline of the literature concerning the importance of 1,2-diamines. This includes their biological significance, their successful application to synthetic chemistry, especially in asymmetric synthesis, and methods available for their preparation. One particular method, the nitro-Mannich reaction, is reviewed in more detail. The synthetic utility of the products of the nitro-Mannich reaction is demonstrated by their application to the synthesis of natural products and pharmaceutical agents. Improvements to the scope of the nitro-Mannich reaction through the development of conjugate addition nitro-Mannich reactions are also discussed, including a brief outline of the methods available for asymmetric conjugate additions to nitroalkenes. The introductory chapter closes with the importance of 1,2-diamine-containing fused heterocycles, especially in pharmacological compounds, and describes some of the methods available for their preparation. The results and discussion chapter gives a detailed account of the work that has been performed towards the development of an expedient synthesis of 1,2-diamine-containing fused heterocycles. The synthesis utilises a highly anti-selective reductive nitro-Mannich reaction to form structurally complex β-nitroamines in high yield. These are subsequently reduced to the corresponding 1,2-diamines, which undergo a palladium catalysed intramolecular N arylation to synthesise an array of fused heterocyclic compounds. This cyclisation reaction can be performed highly selectively to form both 2-aminomethylene indolines and 3-aminotetrahydroquinolines through the use of a trifluoroacetyl protecting group. Details of the optimisation studies for the nitro-Mannich, nitro reduction and intramolecular N-arylation reactions are given. Investigations into the further derivatisation of the heterocyclic products are also presented. Finally, investigations into the development of an alternative synthesis of tetrahydroquinolines utilising an intramolecular nitro-Mannich reaction are discussed. The conclusions drawn from the research have been summarised and future investigations to be carried out discussed, including the application of this new methodology to the synthesis of schizozygine. The experimental section presents detailed preparative methods and analytical data for all novel compounds. Finally, X-ray crystallographic data and a comprehensive list of references are provided in the appendices section.
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Murlykina, M. M., O. V. Kolomiets, Y. I. Sakhno, A. V. Tsygankov, and V. A. Chebanov. "Application of Doebner-type aminoazole based heterocycle acides in Ugi 4CR." Thesis, Ekskluziv Publ, 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/44935.
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Plé-Koerber, Karen. "Approche vers la synthese du nosiheptide : preparation des heterocycles." Reims, 1993. http://www.theses.fr/1993REIMP207.
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Johnson, Comlan Ansah. "Thio-benzazoles et thio-pyridiniques : synthese et etude biologique de monomeres, dimeres et hetero-dimeres benzazolo- et/ou pyridino-acridiniques." Aix-Marseille 2, 1993. http://www.theses.fr/1993AIX22960.
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Lamm, Ashley, and Ashley Lamm. "Fundamental Chemistry of 1,2-Dihydro-1,2-Azaborines." Thesis, University of Oregon, 2012. http://hdl.handle.net/1794/12514.
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Benzene and its derivatives are ubiquitous in chemical research, with applications ranging from material science to biomedical research. 1,2-Dihydro-1,2-azaborine is a benzene mimic which replaces a CC bond with a BN bond. The basic science and applications of 1,2-azaborines is relatively underdeveloped. This thesis expands the fundamental understanding of 1,2-azaborines. Chapter I describes the air and moisture stability of 1,2-azaborines. Chapter II introduces nucleophilic aromatic substitution reactions that the parent 1,2-dihydro-1,2-azaborine will undergo. Chapter III discusses a trimerization reaction that 1,2-dihydro-1,2-azaborine can perform, which is unique from benzene. Chapter IV examines a novel protection free synthesis of 1,2-azaborines, which provides a more direct route to functionalized 1,2-azaborines. Chapter V discusses the novel deprotection of the N-silicon using an amide, giving one of the first 1,2-azaborine pharmaceutical mimics. Finally, chapter VI summarized miscellaneous contributions I have made to the basic science of 1,2-azaborines.
This dissertation includes previously published and unpublished co-authored material.10000-01-01
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Ojwach, Stephen Otieno. "Heterocycle carbonyl pyrazolyl palladium(II) complexes :synthesis, ethylene oligomerisation and polymerisation catalysis." Thesis, University of the Western Cape, 2004. http://etd.uwc.ac.za/index.php?module=etd&.
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Moore, Stephen. "New reactions of lithiated aziridines and pyrrolidines : applications in nitrogen heterocycle synthesis." Thesis, University of York, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485840.
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This PhD thesis describes the original developments of new reactions of lithiated aziridines and pyrrolidines and their use in nitrogen heterocycle synthesis. Chapter one represents a comprehensive overview of the literature covering the different modes of reactivity of lithiated epoxides and aziridines. These include: (i) carbenoid insertion into CH bonds and transannular CH bond insertions, (ii) carbenoid insertion into organolithium reagents (also known as reductive alkylation) and (iii) electrophilic trapping. Chapter two describes the development of a new route to aza-spirocycle-containing compounds using reductive alkylation as a key step. Thus, the reductive alkylation of a range of cyclic substituted p-methoxy aziridines gave high yields of allylic sulfonamides, which were converted into aza-spirocycles using a two-step hydroboration-Mitsunobu protocol. This included our work towards the synthesis of the aza-spirocycle-containing natural product, (±)-cephalotaxine. Chapter three describes the diastereoselective synthesis and organolithium-mediated reactions of a range of p-methoxy aziridines derived from acyclic alkenes. This included a Z-stereoselective reductive alkylation and a novel alkyne forming reaction. The preparation of a N-2,4,6-triisopropylbenzenesulfonyl (Tris) p-methoxy aziridine was also carried out. Chapter four represents the development of a new route for the asymmetric synthesis of 2,3-substituted piperidines. First, the asymmetric lithiation-aldehyde trapping ofNBoc pyrrolidine gave the corresponding amino alcohols with high enantioselectivity and diastereoselectivity. Second, the ring expansion from pyrrolidines to piperidines was carried out. This included a total synthesis of the pharmaceutical (+)-L-733,060 and a formal synthesis of the natural product (+)-swainsonine. A brief overview ofthe literature covering these topics is also included.
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Edwards, Neil. "Applications of allene sulpoxides in heterocycle synthesis and studies towards the herbicidins." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260664.
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Markovic, Tim. "Uitilizing SO2 in functionalized sulfinate synthesis : new methods for heterocycle cross-couplings." Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:26225f4f-b974-48f6-b773-009235d8a269.
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In the following thesis, new methodologies towards the synthesis of a variety of heteroaromatic biaryl molecules are documented. These methods utilize straightforward to prepare and stable sulfinate salts or allyl sulfones, and exploit palladium-catalyzed crosscoupling reactions.
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Arnold, Jeffrey Scott. "Rhodium-catalyzed asymmetric amination of trichloroacetimidates with application to nitrogen heterocycle synthesis." Diss., University of Iowa, 2014. https://ir.uiowa.edu/etd/4565.
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Chiral quaternary centers possessing a bond to nitrogen are an important class of amine compounds, however, methods for their enantioselective preparation remain sparse. The focus of my graduate research described herein has been the development of a novel rhodium-catalyzed regio- and enantioselective allylic aryl amination of tertiary trichloroacetimidates for the synthesis of amine-bearing quaternary centers (also termed α,α-disubstituted amines). Prior to our work, allylic carbonates and acetates had been successfully utilized in transition-metal catalyzed substitution reactions with anilines for the asymmetric synthesis of tertiary centers. In contrast, these electrophiles have not proven useful in dynamic kinetic asymmetric transformations (DYKAT) that yield enantioenriched amine products, and no reports describing the asymmetric preparation of α,α-disubstituted allylic aryl amines via allylic substitution are noted.
Many of the ideas for development of our rhodium-catalyzed amination method were based upon the findings of Overman where linear allylic trichloroacetimidates are utilized in [3,3]-sigmatropic rearrangements and substitution reactions by oxygen nucleophiles under palladium (II) catalysis. Our method diverges from this previous work by application of branched allylic trichloroacetimidates where the olefin component is mono-substituted, and the use of a transition-metal complex capable of facile oxidative addition to an intermediate organometallic complex. We hypothesized that bidentate chelation of these substrates at the imidate nitrogen and the relatively unimpeded olefin by a rhodium (I) complex would lead to rapid ionization to an activated complex and competent electrophile for substitution by neutral aniline nucleophiles. This premise was supported by many control studies and resulted in the development of a highly regioselective amination of branched allylic trichloroacetimidates for the operationally simple synthesis of α-substituted and α,α-disubstituted allylic aryl amines. Work followed utilizing chiral diene ligands that rendered the reaction enantioselective for preparation of enantioenriched tertiary and quaternary amine-containing centers. A highlight of these studies is the first example of DYKAT using a tertiary electrophile and an aryl amine nucleophile. The reaction is of broad substrate scope, is tolerant of varied functionality and substitution patterns on the nucleophilic partner, and solves regioselectivity issues often encountered with some substrate and aniline classes. I end by showing the synthetic utility of our rhodium-catalyzed reaction by applying this method to the synthesis of enantioenriched amino acids and construction of 7-membered nitrogen-containing heterocycles by a 2-step DYKAT amination and olefin hydroacylation sequence.
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FRANCESCONI, VALERIA. "Synthesis and biological evaluation of nitrogen heterocycle systems as potential antiviral agents." Doctoral thesis, Università degli studi di Genova, 2020. http://hdl.handle.net/11567/1001191.
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Viruses are obligate intracellular parasites that consist of either double- or single-stranded DNA or RNA enclosed in a protein coat called capsid. Some viruses also possess a lipid envelope that, like the capsid, may contain antigenic glycoproteins. Most of them contain or encode enzymes essential for their replicative cycle inside host cells, sometimes usurping their metabolic machinery.
Traditional therapeutic approaches have mostly focused on targeting specific viral components or enzymes. This pathogen-directed strategy, while successful in numerous cases, in many others results ineffective due to the emergence of drug-resistance. A different approach, addressed to target host-factors essential for viral replication, has recently draw an increasing attention.
My PhD project aimed at synthesizing new nitrogen heterocycle systems, designed especially against RNA viruses, such as those belonging to Flaviviridae, Orthomyxoviridae and Paramyxoviridae families. Among them there are, respectively, pathogens responsible for diseases with a high epidemiological impact, as BVDV in cattle and HCV in humans, influenza A and B viruses and respiratory syncytial virus (RSV). The project has been organized into the following phases:
1. Chemical synthesis of the novel compound series. During my PhD I designed and synthesized diverse chemical series of different chemotypes, in order to obtain new antiviral agents: the acridine nucleus, the dihydrotriazine scaffold, the benzimidazole ring as well as anilino and benzenesulfonamide derivatives. Previous studies performed by the research group where I develop my Ph.D. thesis identified some prototypes for the different classes endowed with intrinsic antiviral activity; thus, during my Ph.D. research work I explored various possibilities of functionalisation with the aim of increasing their potency and selectivity profiles towards the respective antiviral target.
2. Characterization of the new compounds. Each newly synthesized compound have been characterised by spectroscopic methods (such as UV, IR, 1H-NMR and 13C-NMR) and elemental analysis.
3. Evaluation of cytotoxicity, antiviral activity in vitro, enzymatic assays and computational studies have been performed in collaboration with several national and international research groups, to assess the biological activity and to identify/confirm the respective molecular targets.
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Morin, Marie. "Applications of new phosphorus-based 1,3-dipolar cycloaddition reagents in nitrogen heterocycle synthesis." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117088.
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This thesis describes the study of phospha-Münchnones, a new class of 1,3-dipole. These 1,3-dipoles have been previously demonstrated to be accessible in a one-pot reaction of imines, acid chlorides and organophosphorus reagents, and participate in 1,3-dipolar cycloaddition reactions. The objective of the research described in this thesis is to both understand the reactivity of these dipoles, and exploit their cycloaddition with alkynes and alkenes to synthesize pyrroles and 2-pyrrolines with high regio-, diastereo- and enantioselectivity. Chapter 2 focuses on understanding the factors that control regioselectivity in 1,3-dipolar cycloaddition reactions of phospha-Münchnones with alkynes, as well as the related mesoionic heterocycles Münchnones and Münchnone-imines. While each of the dipoles are established to participate in 1,3-dipolar cycloaddition reactions, until now, no general rules regarding the factors that control regioselectivity have been described. Cycloaddition reactions of the above mentioned dipoles are examined with a range of unsymmetrical electron poor and electron rich alkynes, and by comparing the behavior of these related dipoles, trends are observed in regioselectivity that relates to the alkyne ionization potential. In conjunction with Prof. Houk and Dr. Krenske at UCLA, DFT calculations were performed that provides a rational for the different behaviors of each of these dipoles. Importantly, these 1,3-dipoles display divergent regioselectivity, which can be exploited to synthesize a variety of pyrroles with high selectivity through the use of the appropriate reactant. Similarly, the rational on regioselectivity also allows the prediction of regioselectivity for a wide scope of alkynes. In Chapter 3 we explore the effect of the organophosphorus unit in phospha-Münchnones on their structure, reactivity and regioselectivity. X-ray crystallographic studies demonstrate the significant role of the PR3 unit on the ground state structure of these dipoles and their reactivity. In addition, the results of the theoretical investigation of Chapter 2 are exploited to show how changes in the phosphorus substituents can be used to fine tune regioselectivity of alkyne cycloadditions without modifying the substituents on the final product. In Chapter 4, phospha-Münchnone cycloaddition with alkenes is explored. Different phosphites and phosphonites are tested for their ability to mediate intramolecular cycloaddition with alkenes, and optimum results are obtained with (2-catechyl)PPh. Polycyclic 2-pyrrolines are generated in rapid cycloaddition reactions, in a modular fashion from easily accessible starting materials: olefin-tethered imines, acid chlorides and phosphonites. In addition, the reaction proceeds with high diastereo- and regioselectivity. The utility of this reaction has been extended to other products, including in situ reduction of the 2-pyrroline to pyrolidines, or oxidation to form pyrroles. In Chapter 5, a new way to control the enantioselectivity in 1,3-dipolar cycloaddition reactions is described. By the use of (R)-BINOL-based phosphites, a phospha-Münchnone can be prepared that is easily accessible, modular, yet requires no additional steps to install or remove the chiral fragment. As such, this provides a straightforward approach to control chirality in 1,3-dipolar cycloaddition reactions. This has been used to generate polycyclic pyrrolines and pyrrolidines with three or four stereogenic centers in one pot, and up to 99% ee.Cette thèse décrit l'étude du phospha-Münchnone, une nouvelle classe de 1,3-dipôle. Il a été démontré précédemment que ces 1,3-dipôles peuvent être facilement générés à partir des imines, des chlorures d'acides et de composés organophosphorés et peuvent être utilisés dans des réactions de cycloadditions 1,3-dipolaires. Le but de cette recherche est à la fois de comprendre la réactivité de ces dipôles et de les exploiter dans des réactions de cycloadditions avec des alcynes et des alcènes pour synthétiser des pyrroles et des 2-pyrrolines de façon hautement régio-, diastéréo- et énantiosélective. Le Chapitre 2 focalise sur la compréhension des facteurs qui contrôlent la régiosélectivité des réactions de cycloadditions 1,3-dipolaires avec les phospha-Münchnones et les alcynes ainsi qu'avec des hétérocycles mésoioniques analogues, les Münchnones et les Münchnones-imines. Malgré que chacun de ces 1,3-dipôles soit reconnu pour sa participation aux réactions de cycloadditions 1,3-dipolaires, aucune règle générale concernant les facteurs qui contrôlent la régiosélectivité n'a été encore établie jusqu'à maintenant. Grâce à l'étude des cycloadditions de ces trois 1,3-dipôles avec une gamme d'alcynes asymétriques électron pauvres et électron riches, et par la comparaison des comportements de ces 1,3-dipôles, des tendances au niveau de la régiosélectivité en fonction du potentiel d'ionisation de l'alcyne ont pu être observées. Conjointement avec le Pr. Houk et le Dr. Krenske à L'UCLA, des calculs DFT ont été réalisés et fournissent une explication logique sur les différents comportements de ces dipôles. De plus, ces 1,3-dipôles présentent des régioselectivités divergentes qui peuvent être exploitées pour la synthèse d'une variété de pyrroles avec de hautes sélectivités grâce au choix du réactif approprié. Cette étude permet également la prédiction de la régiosélectivité pour une large gamme d'alcynes. Dans le Chapitre 3, l'effet de l'unité organophosphorée sur la structure, la réactivité et la régiosélectivité du phospha-Münchnone est étudié. Les études aux rayons-X cristallographiques démontrent le rôle important de l'unité PR3 sur l'état fondamental et la réactivité de ces 1,3-dipôles. De plus, les résultats de l'étude théorique du Chapitre 2 sont exploités pour varier de façon logique les substituants du phosphore afin d'améliorer la régiosélectivité des cycloadditions d'alcynes sans modifier les substituants du produit final. Dans le Chapitre 4, la cycloaddition du phospha-Münchnone avec des alcènes est explorée. Différents phosphites et phosphonites sont testés pour leur capacité à participer aux cycloadditions intramoléculaires d'alcènes, et les résultats optimaux sont obtenus avec le (2-catechyl)PPh. Les 2-pyrrolines polycycliques sont générées dans des réactions de cycloadditions rapides, de façon modulaires et à partir de réactifs facilement accessibles : des imines contenant un alcène, des chlorures d'acyles et des phosphonites. De plus, la réaction procède avec une haute régio- et diastéréosélectivité. L'utilité de cette réaction a été étendue à d'autres produits, avec la réduction in situ des 2-pyrrolines en pyrrolidines, et avec l'oxydation en pyrroles. Dans le Chapitre 5, une nouvelle façon de contrôler l'énantiosélectivité des réactions de cycloadditions 1,3-dipolaires est décrite. Grâce à l'utilisation d'un phosphite substitué par un groupement (R)-BINOL, un nouveau phospha-Münchnone peut être synthétisé avec l'avantage d'être facilement accessible, modulaire, et ne requiert aucune étape supplémentaire pour installer ou enlever le fragment chiral. Cela offre une approche simple pour contrôler la chiralité des réactions de cycloadditions 1,3-dipolaires et générer des pyrrolines et des pyrrolidines polycycliques avec trois ou quatre centres stéréogènes de façon « one-pot » et jusqu'à 99% ee.
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Bower, John F. "Cyclic sulfamidates as versatile intermediates for N-heterocycle construction : applications in total synthesis." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439953.
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Uzelac, Eric James. "Thiazole vs. Thiophene: Heterocycle Effects on the Properties of Fused-Ring Conjugated Materials." Diss., North Dakota State University, 2017. https://hdl.handle.net/10365/29091.
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Conjugated polymers and related molecular materials comprise a field of materials chemistry focused on the development of semiconducting organic plastics that find use in applications such as organic solar cells and organic light-emitting diodes. The optical and electronic properties of these molecules, such as absorption and emission of light, can be tuned through engineering at the molecular level. However, many of the current molecules of choice suffer from high-lying frontier orbitals, which results in a mismatch of energy levels to common components of electronic devices along with potential oxidative instability, constraining device performance in real environments. To rectify these issues, the electron-deficient thiazole heterocycle has been incorporated into fused-ring conjugated motifs of both organic and inorganic nature. The new thiazole materials all exhibited the expected stabilization of their frontier orbitals compared to the thiophene analogues. The absorption profiles of the thiazole materials are similar to the thiophene analogues, but with reduced molar absorptivity as a general trend, potentially limiting the efficiency of thiazole derived materials as components of photovoltaic devices. Through experimentation and development of multiple new classes of organic and inorganic thiazole materials, it was found that a larger proportion of thiazole content correlates to a larger decrease in molar absorptivity, but also a larger relative stabilization of the frontier orbitals. The limitations in molar absorptivity can thus be mitigated to an extent by increasing the molecule’s effective conjugation path through functionalization with additional conjugated units, but with the countereffect of less-stabilized frontier orbitals.