Dissertations / Theses on the topic 'Heterocyclic'
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1
Locke, Julie Myree, University of Western Sydney, College of Health and Science, and School of Biomedical and Health Sciences. "Synthetic and conformational studies of hexahydropyrimidines and related heterocycles." THESIS_CHS_BHS_Locke_J.xml, 2003. http://handle.uws.edu.au:8081/1959.7/638.
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This thesis explores the synthesis and conformational behaviour of hexahydropyrimidines and related heterocycles, with particular emphasis on 5- hyrdohexahydropyrimidines. The conformational behaviour of these compounds was investigated using dynamic NMR spectroscopy, molecular modelling techniques and X-ray crystal structure analysis. The conformational behaviour of 5- hyrdohexahydropyrimidine, hexahydropyrimidine and their analogous oxygen compounds as well as a series of hexahydropyrimidines with various exocyclic substituents, were examined. The preferred conformations of all these compounds are attenuated by a combination of steric and electronic influences. These influences include intramolecular hydrogen bonding as well as anomeric and gauche interactions. The conformational behaviour of the selected seven membered benzodiazepine rings, which share structural characteristics with the six-membered 5- hyrdohexahydropyrimidines was also explored. The increased flexibility of the seven membered rings facilitates intramolecular hydrogen bonding, which in turn retards ring inversion in these systemsDoctor of Philosophy (PhD)
2
Lewis, William. "Chiral Heterocyclic Ligands." Thesis, University of Canterbury. Chemistry, 2007. http://hdl.handle.net/10092/1383.
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This thesis describes the preparation and characterisation of a number of homochiral coordination and metallosupramolecular assemblies. These species were formed from the reaction of chiral pyridine and quinoline containing ligands and metal ions. The combination of traditional coordination chemistry and supramolecular interactions led to a range of polymeric and network structures being formed. The ligands used in this thesis can be divided into two broad categories: alkaloids and ligands derived from them, and amino acid-based ligands. In the first category three new ligands were synthesized, and a variety of routes towards alkaloid-based homochiral ligands were investigated. The second category focused on three ligand motifs, and resulted in the preparation of 16 ligands. These two categories of ligands were reacted with a range of metal salts to investigate their coordination and supramolecular chemistry. The structure of twenty complexes was determined by single crystal X-ray crystallography. The complexes had a range of structures, with discrete and polymeric species being formed. Hydrogen bonding was an important feature in the supramolecular chemistry of the complexes, playing a different role in different series of complexes. Two chiral coordination polymers and one chiral coordination network were synthesized. All three of these structures possessed directionality to some degree: in the coordination network and one of the polymers the directionality is counterbalanced by the opposite directionality being present in the crystal, while the second coordination polymer is generated by the screw axis present and has a high degree of overall directionality.
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Civcir, Pervin Unal. "Extended heterocyclic systems." Thesis, University of East Anglia, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332359.
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Karatza, Mary-Helen. "Extended heterocyclic systems." Thesis, University of East Anglia, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359850.
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Collier, Steven James. "Heterocyclic ortho-quinodimethanes." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366249.
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White, Lindsay Anne. "Heterocyclic o-quinodimethanes." Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262608.
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Liu, Jing. "Heterocyclic small molecule peptidomimetics." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3125.
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Myers, Eddie Leonard. "Heterocyclic aromatic nucleic acids." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79056.
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In order to investigate the role played by the aromatic moiety of Aromatic Peptide Nucleic Acids (APNAs) in their ability to hybridize with RNA and DNA, as well as improve the solubility of APNA oligomers in aqueous solutions, a new generation of heterocyclic monomers were designed. APNA monomers, where the nucleobase can be thymine, cytosine adenine or guanine, with backbones contain thiophene and pyridine moieties were synthesized. Suitably protected APNA-APNA and PNA-APNA dimers were also synthesized as building blocks for the solid phase synthesis of APNA-PNA chimeras and APNA homopolymers. Due to the instability of the pyridine-containing APNA oligomers to the harsh acidic conditions required to cleave oligomers from the MBHA resin, a new protocol was developed for the synthesis of these molecules on the trityl chloride resin. Oligomers of PNA and APNA-PNA chimeras were successfully synthesized on this solid support, and cleaved from the resin using mild acidic conditions.
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Jones, Richard G. "Studies in heterocyclic synthesis." Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238268.
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Chauncey, Marek Anthony. "Reactions heterocyclic quinone methides." Thesis, University of Ulster, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328193.
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Wren, S. A. C. "Cycloadditions of heterocyclic sulphinylamines." Thesis, University of York, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377290.
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Young, Richard Getliff. "Tetrazoles in heterocyclic synthesis." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47727.
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Garrison, Jered C. "Silver N-Heterocyclic Carbenes." University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1124128998.
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Caruthers, Heather Anne. "Applications of heterocyclic synthesis." [Ames, Iowa : Iowa State University], 2009.
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Nicolson, Neil James. "Some new heterocyclic thermosets." Thesis, University of St Andrews, 1996. http://hdl.handle.net/10023/15293.
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The original aim of this project was to investigate the possibility of synthesising a novel polymer system combining the best features of cyanate ester resins and epoxy resins. Chapter 1 presents the historical background for both types of resin. The remaining three chapters describe attempts to achieve this aim by a) finding a cyanate ester that cures at a lower temperature than those in current commercial use (Chapter 2); b) using mixed epoxy and cyanate ester resins (Chapter 3); and c) designing chemically completely novel polymers from knowledge of the existing ones (Chapter 4). In Chapter 2 it was revealed that different cyanate esters cure at different temperatures, but that no obvious correlation exists between curing temperature and either steric or electronic effects of the ring substituents. The mixing of two dicyanate esters, one of which cures at a lower temperature than the other, leads to some reduction in the overall curing temperature required, but not sufficient to warrant further study at this stage. In Chapter 3 the usefulness of a previously proposed co-reaction between cyanate esters and epoxides was examined. Previous work in this area is full of inconsistencies that put many of the proposed conclusions in doubt. Further examination of the alleged co-reaction reveals that any such co-reaction is unpredictable, can vary significantly with reaction conditions and is in any case a minor reaction pathway by comparison with the self-reactions of the two individual reactants. It was therefore decided that further pursuit of this strategy was also likely to prove unrewarding in the short term. In Chapter 4 a study was made into the effects of including novel monomers in a standard epoxy resin system. These novel monomers had a cyanurate backbone with epoxide functionality, and can be cured at the lower temperatures of epoxy resins. Tests on the properties (mechanical, dielectric, water absorption, fracture toughness etc.) of these polymers were of a preliminary "scouting" nature, but are sufficiently promising to encourage further study.
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Bemowski, Ross David. "Novel N-heterocyclic dicarbene ligands and molybdenum and dimolybdenum N-heterocyclic carbene complexes." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/1291.
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The syntheses of a new class of polycyclic TriAmino DiCarbenes (TADCs), based on 3,9-diazajulolidine, and their precursors and adducts are described.
Starting with 2,6-dimethyl-nitrobenzene, 2,6-bis ((alkylamino)methyl)anilines (alkyl = isopropyl, mesityl, and tert-butyl) were synthesized in 40% yield over five steps. These triamines were then di-cyclized stepwise to diformamidinium dications or formamidinium/2-methoxyformaminals using oxonium salts and trialkyl orthoformates. A diformamidinium dication was characterized by single-crystal X-ray diffractometry. Treatment with various bases, particularly lithium hexamethyldisilylazide, led to the novel TADCs and monocarbenes, two of which were isolated and characterized by 1H and 13C NMR spectroscopies. In both cases, treatment with elemental sulfur trapped the TADCs as dithiobiurets. No TADC-transition metal complexes were successfully isolated from reactions of the diformamidinium dications or LiHMDS TADC complex with a number of transition metal complexes.
With the exception of these two cases, all other TADCs were not isolated because they rapidly reacted to form dimers, trimers, and tetramers. One of these dimers was isolated and its structure determined using 1D and 2D NMR spectroscopies, along with high-resolution electrospray ionization mass spectrometry. This revealed that the TADC had dimerized to form an ene-triamine, likely via 1,3-shift of a benzylic proton.
Novel N-heterocyclic Carbene (NHC) complexes of molybdenum were also synthesized and characterized. Reaction of Cp2Mo2(CO)4 (Cp = C5H5) with dimesityl-imidazol-2-ylidenes (IMes) or dimesityl-imidazolidin-2-ylidenes (SIMes) yielded the molybdoradicals CpMo(CO)2(NHC) (NHC = IMes or SIMes). The carbonyl infrared stretching frequencies and the relative metal-to-NHC π-backbonding for IMes and SIMes complexes are compared. Reaction of the less bulky dimethyl-imidazol-2-ylidene (IMe) with Cp2Mo2(CO)4 yielded the Mo-Mo triple bond complex Cp2Mo2(CO)3(IMe) by CO substitution. This is the first example of an NHC-ligated metal-metal multiply bonded complex. Single crystal X-ray diffractometry of these new organomolybdenum and organodimolybdenum complexes is discussed.
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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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Locke, Julie Myree. "Synthetic and conformational studies of hexahydropyrimidines and related heterocycles." Thesis, View thesis, 2003. http://handle.uws.edu.au:8081/1959.7/638.
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This thesis explores the synthesis and conformational behaviour of hexahydropyrimidines and related heterocycles, with particular emphasis on 5- hyrdohexahydropyrimidines. The conformational behaviour of these compounds was investigated using dynamic NMR spectroscopy, molecular modelling techniques and X-ray crystal structure analysis. The conformational behaviour of 5- hyrdohexahydropyrimidine, hexahydropyrimidine and their analogous oxygen compounds as well as a series of hexahydropyrimidines with various exocyclic substituents, were examined. The preferred conformations of all these compounds are attenuated by a combination of steric and electronic influences. These influences include intramolecular hydrogen bonding as well as anomeric and gauche interactions. The conformational behaviour of the selected seven membered benzodiazepine rings, which share structural characteristics with the six-membered 5- hyrdohexahydropyrimidines was also explored. The increased flexibility of the seven membered rings facilitates intramolecular hydrogen bonding, which in turn retards ring inversion in these systems
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Armugam, S. "Studies on N-Heterocyclic Compounds." Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/108.
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The thesis entitled "Studies on N-Hetero cyclic Compounds: (a) Reaction of 5,6,7,8-Tetrahydroisoquinolines with Vilsmeier Reagent and (b) Amide Induced in situ Alkylation of 5,6-Dihydroisoquinolines" is presented in two parts. Part I involves a study of the Vilsmeier reaction of 4-cyano-1,3-dihydroxy-5,6,7,8 tetrahydroisoquinoline derivatives, while Part II concerns the in situ alkylation of l-alkyl-4-cyano-3-methoxy-5,6- dihydroisoquinolines in presence of KNH2/liq.NH3.
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Perrins, Ross. "Heterocyclic chemistry of trithiazyl trichloride." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283411.
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Jones, Louise. "Combinatorial, heterocyclic and guanidine chemistry." Thesis, Bangor University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429865.
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Hayes, Simon Jonathan. "Flow system for heterocyclic synthesis." Thesis, Cardiff University, 2007. http://orca.cf.ac.uk/54663/.
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The potential of the silver-catalysed cyclisation has been illustrated by the synthesis of furans, pyrroles and pyrazole-N-oxides. With yields predominantly being >95%, and ubiquitous high purity, the results herein show the compatibility of many substituents including alkyl, aryl and silyl, to name but a few. Extended investigations have improved our understanding of reaction rates, the effect of stereochemistry and the use of protection strategies as well as identifying a handful of limitations. With the above results in hand, and a desire to recognise the practical advantages of a metal-catalysed procedure, we have further described two continuous flow systems for heterocyclic synthesis. The first, a trickle-bed reactor, produces heterocycles in excellent yields (>95% except where volatile products were produced) and has been shown to exhibit < 1 ppm silver leaching. Our understanding of the optimal flow rates, catalyst loading and practical attributes associated with such a reactor is then described. The second, a supercritical carbon dioxide : ionic liquid system, has been shown to produce furans in excellent yields (>95%), when used in batch mode, and in slightly lower yield (>70%) when used in a continuous fashion. Once again silver leaching was seen to be <1 ppm. The success of these two systems, and the speed in which their success was achieved, clearly demonstrates the ease of working with silver-catalysed cyclisations. In a further brief foray, the use of heat and microwave irradiation is discussed in view of potential applications to other continuous systems. Finally, several specific applications of the silver-catalysed cyclisation have been shown. It is seen that this procedure is suitable for the synthesis of scented furans and has uses in the preparation of heterocyclic substrates, which can be used for bigger and better things. One such example, which is described in Chapter 6, is the formation of oxepan-4-ones, oxepin-4-ones and oxocins-5-ones from their corresponding furyl alcohols.
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Chilloux, Aurelie Amelia. "Synthesis of anticancer heterocyclic quinones." Thesis, University of Nottingham, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.537637.
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Henderson, Neil. "Studies in nitrogen heterocyclic chemistry." Thesis, University of East Anglia, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280300.
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Fishwick, C. W. G. "Azaxylylenes and their heterocyclic analogues." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356266.
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Brown, J. W. "Studies of heterocyclic reaction mechanisms." Thesis, Bucks New University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356206.
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Jenkins, Graham. "Heterocyclic analogues of ortho-xylylene." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279695.
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Large, Janet. "Asymmetric induction using heterocyclic precursors." Thesis, Open University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272951.
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Hu, Gang. "Conducting polymers from heterocyclic compounds." Thesis, Open University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240331.
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Ellul, Charles. "Trimetallic N-heterocyclic carbene complexes." Thesis, University of Bath, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538279.
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Emans, John. "Synthesis of novel heterocyclic polymers." Thesis, University of St Andrews, 1987. http://hdl.handle.net/10023/15299.
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This work details the synthesis, characterisation and fabrication of a range of copolyesters, containing various angular disrupters, especially disubstituted 2,5-diphenyl- -1,3,4-oxadiazoles. These disrupters were incorporated into the polymers, to reduce the temperature at which the polymers may be processed, to enable their fabrication into fibres. The majority of the polymers prepared were found to be liquid crystalline. However, if the angular disrupter content of the polymer was high, it was found that the resultant polymers were non-liquid crystalline. The polymers were prepared by a melt acidolysis process carried out under a nitrogen flow and subsequently under vacuum, as described in Chapter 3. Eighteen of the polymers were characterised in some detail, though a measure of the relative molecular weights was thought to be of little importance in this work, since all polymers were of a different composition. Differential scanning calorimetry and hot-stage microscopy revealed that several of the polymers had rather unusual melting behaviour. The eighteen polymers that were closely characterised were spun into fibres, using a small melt-spinning apparatus that was designed and produced by Bradford University Research Ltd, The resultant fibres were characterised by differential scanning calorimetry, X-ray diffraction end tensile testing. The general conclusion of the work is that although a reduction in the processing temperature of the polymer is achieved by the incorporation of angular disruptors, which is advantageous, the tensile strength and thermal stability of the fibres produced from such polymers are reduced.
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Bratenko, M. K. "Benzoazepinopyrazoles – a new heterocyclic system." Thesis, БДМУ, 2022. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/19533.
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Sprick, Reiner Sebastian. "Polytriarylamines containing fused ring and heterocyclic structures prepared using N-heterocyclic carbene complexes of palladium." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/polytriarylamines-containing-fused-ring-and-heterocyclic-structures-prepared-using-nheterocyclic-carbene-complexes-of-palladium(c09188eb-490b-452c-945a-22979f58c76d).html.
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For the preparation of semiconducting polymers often ‘standard’ catalytic systems are used without further optimisation. New ligands, such as N-heterocyclic carbenes have shown excellent activity in cross-coupling reactions (e.g. Suzuki-Miyaura reaction, or Hartwig-Buchwald amination). These systems show excellent conversions under mild conditions and even allow the use of aryl chlorides as reagents. Nevertheless, previously no system has been reported for the synthesis of conjugated polymers, e.g. the Suzuki polycondensation or Buchwald-Hartwig type polycondensation using these catalysts. A NHC-Pd based catalytic system was optimised for a polyamination reaction and the catalyst [(IPr)Pd(allyl)Cl] was found to be the most active. Polytriarylamines were synthesised using the optimised catalytic system and tested in organic field-effect transistors. Mobilities found were low which was found to be attributed to the presence of high molecular weight fractions. Molecular weights were controlled using an in situ end-capping approach and polymers tested in the semiconducting layer of OFETs gave similar mobilities tothose reported earlier. Several polytriarylamines, which have not been reported previously, were synthesised using NHC-chemistry and the in situ end-cappingapproach, as well as polytriarylamines that have been reported previously using Pd/phosphine catalysts. One library containing polymers based on biphenyles andbridged biphenyles and another library containing polymers with bridged oligoarenes were synthesised. Suzuki polycondensation was also studied besides the polyamination protocol and low catalyst loadings and reaction temperatures could be realised using a NHC-Pd catalyst. Sulfur containing monomers that could not be polymerised using the polyamination were polymerised successfully. All polymers were fully characterised and studied as the active layer in organic field-effect transistors. The highest mobilities determined for these polymers (~10-2 cm2/Vs) is close to the highest reported for this class of polymer reported to date.
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Nyoni, Dubekile. "Application of the Baylis-Hillman methodology in the construction of novel heterocyclic derivatives." Thesis, Rhodes University, 2008. http://eprints.ru.ac.za/1134/.
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Ganto, Mlungiseleli MacDonald. "Application of Baylis-Hillman methodology in the construction of complex heterocyclic targets." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1006703.
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Baylis-Hillman reactions using various aromatic aldehydes, activated alkenes and catalysts have been used to: - access an extensive range of poly-heterocyclic products;explore chemoselectivity; and optimise reaction efficiency. Chromone-3-carbaldehydes and chromone-2-carbaldehydes, prepared via Vielsmeier-Haack and Kostanecki-Robinson methodology, respectively, have been used as Baylis-Hillman substrates with four different catalysts, viz., 1,4-diazabicyclo[2.2.2]octane (DABCO), 3-hydroxyquinuclidine (3-HQ), imidazole and N’,N’,N’,N’- tetramethylpropanediamine (TMPDA), and with methyl vinyl ketone (MVK), methyl acrylate, cyclic enones (2-cyclohexen-1-one, 2-cyclopenten-1-one and chromones) as activated alkenes. Reactions of the chromone- -carbaldehydes with MVK afforded dimeric Baylis-Hillman adducts when catalyzed by DABCO but when the same reactions were repeated using 3-HQ as catalyst, the dimeric products were accompanied by tricyclic Baylis-Hillman adducts. Use of excess MVK, however, led to mixtures of the normal Baylis-Hillman adducts and the tricyclic adducts – interestingly, with the apparent absence of the dimeric products. While reactions of chromone-3-carbaldehydes with methyl acrylate afforded the normal Baylis-Hillman adducts, the chromone-2- carbaldehydes produced, instead, rearrangement products, consistent with an earlier, single observation. Reactions of 2-nitrobenzaldehydes with cyclic enones using imidazole as catalyst afforded the normal Baylis-Hillman adducts, reductive cyclisation of the 2-cyclohexen-1- one and 2-cyclopenten-1-one adducts, using acetic acid and iron powder, afforded the corresponding quinoline erivatives. Treatment of cyclic enones with pyridine-2-carbaldehydes and quinoline-2-carbaldehydes using TMPDA as catalyst generally gave the expected Baylis-Hillman adducts. However, indolizine derivatives were isolated directly from Baylis-Hillman reactions involving pyridine-2-carbaldehydes and 2-cyclohexen-1-one. The remaining Baylis-Hillman adducts were cyclized to the corresponding indolizines by treatment with acetic anhydride both under reflux and under microwave-assisted conditions, the latter approach providing remarkably rapid and efficient access to the polycyclic products. Computer modelling studies have been conducted on selected polycyclic products at the Molecular Mechanics (MM), Quantum Mechanical (QM) and Density Functional (DFT) levels. The theoretical results have been used to calculate UV, IR and NMR absorption data, which have been compared, in turn, with the experimental spectroscopic data. Use has also been made of the estreNova NMR prediction programme and, generally, good agreement has been observed between the predicted and experimental spectroscopic data.
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Nocanda, Xolani Wittleton. "Applications of Baylis-Idllman methodology in the synthesis of chromene derivatives." Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1018257.
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The reaction of salicylaldehyde with various activated alkenes, viz., methyl vinyl ketone, ethyl vinyl ketone, phenyl vinyl sulfone, phenyl vinylsulfonate, acrolein and acrylonitrile, under Baylis-Hillman conditions, has been found to proceed with the chemoselective formation of chromene derivatives. The reaction conditions have been optimised and chromene derivatives have been obtained in isolated yields up to 87 %. The generality of the reaction, using 1,4-diazabicyclo[2.2.2]octane (DABCO), as the catalyst, and a heterogeneous (chloroform-water) solvent system, has been established using a range of salicylaldehyde derivatives,. including 2-hydroxynaphthaldehyde. The formation of chromene derivatives, under these conditions, has been assumed to proceed via an initial, Baylis-Hillman reaction, followed by cyclisation involving intramolecular conjugate addition, and subsequent dehydration. Evidence supporting this sequence has been obtained from the isolation ofBaylis-Hillman products from reactions involving the use of tertbutylclimethylsilyl-protected salicylaldehyde, 4-hydroxybenzaldehyde and tert-butyl acrylate as substrates. The potential of the ''Baylis-Hillman zwitterion" to participate as a donor species in Michael-type addition reactions has been explored and a series of climeric products has been isolated. The Baylis-Hillman methodology has also been successfully extended to the synthesis of sulfurcontaining heterocyclic systems, and a range of 3-substituted thiochromenes has been obtained in moderate yields, using 2,2'-dithiobenzaldehyde and various activated alkenes in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as catalyst. The electron-impact mass spectra of selected chromene and thiocbromene derivatives have been investigated permitting comparison of the fragmentation of the oxygen- and sulfur-containing analogues. In a study directed at the synthesis of potential HIV -1 protease inhibitors, chromene- and thiocbromene-containing analogues of the clinically useful drug, ritonavir, have been prepared. Thiochromene and chromene derivatives were converted to the corresponding 3 -carboxylic acids and coupled with a specially prepared, hydroxyethylene dipeptide isostere to afford ritonavir analogues containing cbromene and thiochromene termini in ca. 60% yield.
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Bangcuyo, Carlito Ganayo. "Synthesis of heterocyclic poly(aryleneetheynylene)s." Available online, Georgia Institute of Technology, 2006, 2004. http://etd.gatech.edu/theses/available/etd-01112005-182450/.
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Thesis (Ph. D.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2007.Tolbert, Laren, Committee Member ; Weck, Marcus, Committee Member ; Bunz, Uwe, Committee Chair ; Srinivasarao, Mohan, Committee Member.
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Bangcuyo, Carlito Ganayo. "Synthesis of Heterocyclic Poly(aryleneetheynylene)s." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14011.
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Poly(arylenenethynylene)s or PAEs are an interesting class of conjugated polymers that have potential uses in the field of thin film transistors, organic LEDs, sensors, and molecular wires. The field of PAEs have grown in recent years, however very few of its conjugated polymers have a heterocyclic motif contained within them. We have designed some conjugated heterocyclic polymers that contain quinoline, benzothidiazole, and quinoxaline. These polymers show interesting ionochromic and solvochromic effects as well as unusual solid state properties. Some of these polymers will demonstrate their ability to form fascinating nanostructures by use of either mesoporous discs or gold mediated nanotubes. Finally, we also have produced peralkynylated heterocyclic molecules for use in potential n-semiconductive devices. These molecules are not only aesthtically pleasing, but versatile molecules that could be used in conjugated PAEs.
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Miah, Soyfur. "The metallocarbene route to heterocyclic compounds." Thesis, Loughborough University, 1997. https://dspace.lboro.ac.uk/2134/26972.
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Leu, Chao-Wei Chemistry Faculty of Science UNSW. "Synthesis of heterocyclic analogues of phytoestrogens." Publisher:University of New South Wales. Chemistry, 2008. http://handle.unsw.edu.au/1959.4/40824.
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The pyrrolo[3,2,1-ij]quinolin-6-one ring system was synthesised from 3-aryl-4,6-dimethoxyindoles and 2,3-disubstituted-4,6-dimethoxyindoles. The reaction of 4,6-dimethoxyindoles under Friedel-Crafts or Vilsmeier-Haack acylation gave the 2- and 7-indolyldeoxybenzoins in good yield. Cyclisation of 7-indolyldeoxybenzoins with N,N-dimethylformamide dimethyl acetal as a one carbon reagent gave the pyrroloquinolin-6-ones in high yield. Reduction of pyrroloquinolin-6-ones with hydrogen gas and 10% palladium on carbon or lithium aluminium hydride yielded the dihydropyrroloquinolin-6-ones. Demethylation of pyrroloquinolin-6-ones with 48% hydrobromic acid in glacial acetic acid gave a mixture of the monohydroxy and dihydroxy analogues in high yield. The synthesis of quinolin-4-ones using the Conrad-Limpach method was attempted using three different cyclisation conditions such as Dowtherm A, polyphosphoric acid and a mixture of diphenyl ether and methanesulfonic acid. Quinolin-2-ones such as 4-methyl-3-aryl-, 3,4-diaryl- and 3-aryl-4-benzyl-5,7-dimethoxyquinolin-2-ones could be synthesised from either the N-phenylacetylaniline or the N-trifluoroacetyl aniline strategy. Attempted reduction of the quinolin-2-ones with standard metal hydride reagents was unsuccessful. However reduction was achieved via the conversion of quinolin-2-one to the corresponding 2-chloroquinoline followed by reaction of the chloroquinoline with zinc powder and glacial acetic acid to produce a novel, highly substituted quinoline system. Demethylation was successfully carried out with 48% hydrobromic acid in glacial acetic acid to give the trihydroxyquinolin-2-one in high yield. The reactions of 4-substituted-5,7-dimethoxyquinolin-2-ones and the corresponding 2-chloroquinolines as potential organic intermediates were explored. Facile formylation of both quinolin-2-ones and 2-chloroquinolines was observed under Vilsmeier-Haack conditions while acetylation was successful under Friedel-Crafts conditions using antimony (V) pentachloride as the Lewis acid. Further reaction of 8-formyl-quinolin-2-one with 1,2-diaminobenzene in N,N-dimethylformamide led to the formation of a new 8-(benzimidazolyl)-quinolin-2-one ring system. The quinolin-2-ones exhibited selective electrophilic substitution at the C8 position for a range of reactions. However, an unexpected nitration occurred at the C3 position for the 4-methoxy and 4-phenyl-5,7-dimethoxyquinolin-2-ones with good yields. A series of novel 4,6-hydroxylindoles was successfully synthesised from the corresponding methoxy analogues in high yield using anhydrous aluminium chloride. When 3-(4-bromophenyl)-4,6-dimethoxyindole was reacted with 48% hydrobromic acid in glacial acetic acid a 2,2?-indolylindoline dimer was formed. The 5,7-dihydroxyquinolin-2-ones were similarly synthesised in high yield using anhydrous aluminium chloride in chlorobenzene.
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Ryley, Stephen. "Competitive doping in heterocyclic conducting polymers." Thesis, Coventry University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362077.
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Tang, Lam T. "New routes to heterocyclic product families." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365338.
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Xiong, Xin. "Synthetic approaches towards heterocyclic natural producers." Thesis, Cardiff University, 2005. http://orca.cf.ac.uk/55520/.
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A variety of tri- and tetrasubstituted pyridines are prepared by new one-pot processes, developed by modification and improvement of the traditional Bohlmann-Rahtz reaction. The use of zinc(II) bromide catalysis, microwave irradiation and conductive heating in a sealed tube is described to facilitate rapid Michael addition-cyclodehydration of an enamine and alkynone in a single synthetic step and with total control of regiochemistry. Expanding the Bohlmann-Rahtz heteroannulation reaction leads to the development of a mild one-pot three-component syntheses of pyridines, a tandem oxidation-heteroannulation process for one-pot synthesis of pyridines from propargylic alcohols, a highly facile combined three-component tandem oxidation-heteroannulation process and a novel tetrasubstituted bromopyridine synthesis mediated by N-bromosuccinimide. The synthesis of dimethyl sulfomycinamate (13), the acidic methanolysis product of the sulfomycin family of thiopeptide antibiotics, from methyl-4-(trimethylsilyl-2-oxobut-3-ynoate (216) is achieved in 13 steps by the Bohlmann-Rahtz heteroannulation of 1-(oxazol-4-yl)enamine 252 or in 12 steps and 9% overall yield by three-component cyclocondensation with N-[3-oxo-3-(oxazol-4-yl)propanoyl]serine 251 and ammonia in methanol, in a 2,3,6-trisubstituted pyridine synthesis that proceeds with total regiocontrol. Bohlmann-Rahtz reaction of a chiral non-racemic enamine 312 and thiazolylpropynone 114 gives a terminal-protected pyridine-containing gamma-amino acid 311 in high optical purity in a sequential one pot multicomponent reaction that proceeds with total control of regiochemistry and with minimal racemisation. Further elaboration has established the first synthesis of the gamma-lactam acidic hydrolysate of the macrocyclic thiopeptide antibiotic cyclothiazomycin, a selective rennin inhibitor, in only four steps and 30% overall yield and has confirmed its structure.
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Wilson, Jennifer M. "Synthesis of biologically active heterocyclic compounds." Thesis, University of Glasgow, 2007. http://theses.gla.ac.uk/45/.
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More than 11 million people worldwide are diagnosed with cancer every year. New cancer drugs are required that are more effective and selective. Nitrogen mustard alkylating agents crosslink DNA inhibiting transcription and replication. Use of the mustard pharmacophore as part of a macrocycle allows metal complexation and produces a prodrug. Hypoxic tumour cells have increased concentrations of reductase enzymes which could lead to reduction of the complex in situ and release of a cytotoxic drug. Human African Trypanosomiasis is commonly known as Sleeping Sickness and affects over 36 countries of sub-Saharan Africa. It is transmitted to humans by the tsetse fly which carries the parasitic subspecies Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense. Any compounds synthesised would also be tested to assess their potential as anti-parasitic agents. Parker synthesised a range of polyazamacrocycles. Testing of compound A in vitro gave highly efficient DNA crosslinking activity. Copper complexes were formed of the macrocycles and B was found to be 24 times more toxic against hypoxic cells than oxic cells thus exploiting tumour hypoxia and creating a selective drug. Jones synthesised a range of oxaazamacrocycles such as C which when tested in vitro exhibited comparable cross-linking activity to the azamacrocycles although it proved impossible to synthesise the corresponding copper complexes. It was decided to vary the leaving group on the alkylating arms to see if the DNA crosslinking results could be improved. Eight carbamates and the corresponding copper complexes were synthesised. The R-groups were alkyl and aromatic. Anti-cancer DNA crosslinking and hypoxia selectivity results were disappointing however, a number of compounds displayed significant activity when tested against T. brucei. A range of thiaazamacrocycles would complete the set of heteroatom-containing macrocycles (N, O, S) and might produce good DNA crosslinking results. It might also be possible to synthesise the corresponding copper complexes producing prodrugs. Six thiaazamacrocycles were synthesised and 2-hydroxyethyl arms were attached. However it proved impossible to isolate the desired alkylating agents with the 2-chloroethyl arms. In the body, the p53 protein activates the transcription of specific genes. In healthy cells, the levels of p53 have to be kept to a minimum to allow the normal running of the cell, e.g. growth and replication. This function is carried out by the HDM2 protein, which forms an auto-regulatory feedback loop with p53. In some tumours, the p53 function is disrupted due to genetic mutations of p53. However other tumours possess ‘wild type’ p53 – this type of p53 has lost the ability to respond to oncogenic stress due to over-expression of HDM2. Drugs that inhibit HDM2 should cause stabilisation of p53 and induce apoptosis in cancer cells. A small library of 5-deazaflavins were synthesised and biologically tested producing some interesting biological results.
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MacDonald, Ranald John. "Novel routes to heterocyclic Azo compounds." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5787.
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The potential use of electron-deficient heterocyclic azo compounds as inkjet dyes was explored. 2-Nitrosopyridine could be used to form a series of azo compounds via the Mills’ reaction with electron-rich aromatic amines. Conditions for this process were optimised by varying solvent and pH. In the presence of ethers, 2-nitrosopyridine is quickly reduced to azoxypyridine. This reaction follows first order kinetics; diethyl and diisopropyl ether react at similar rates, whereas cyclic ethers such as THF are far slower. Organic bases such as Hunigs base were also found to promote formation of azoxypyridine. The mechanism of this reduction was studied. The electrochemistry of 2-nitrosopyridine and azoxypyridine was also explored. Using the optimised conditions for the Mills’ reaction, 2-nitrosopyridine not only reacts with electron-rich amines but also electron-deficient examples. The series was also expanded to include other heterocycles as well as pyridine via the corresponding heterocyclic nitroso compound. Other nitroso compounds prepared were 1- nitrosoisoquinoline, 2-nitrosopyrazine, 4-nitrosopyrimidine and 2-nitrosopyrimidine. The absorption maxima of azo compounds prepared from these precursors were found to correlate with the values for the corresponding azobenzenes. 2-Nitrosopyridine and 2-nitrosopyrimidine react with diamines to give monoazo products. These in turn could be diazotised and coupled with various components to give either bisazo or trisazo compounds. These dyes were tested for their ozone and light fastness properties. The bisazo examples were found to have good ozone fastness but poor light fastness. The pyrimidine examples only showed a slight improvement in ozone and light fastness compared to their pyridine analogue. 2,3-Phthalocyanines are important components in cyan dyes. New routes to precursors of these compounds were explored using flash vacuum pyrolysis (FVP).
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Casely, Ian J. "Electropositive metal N-heterocyclic carbene complexes." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/3873.
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The first chapter is an introduction to the f-elements, with a focus on the synthesis and chemistry of tetravalent cerium complexes. The synthesis, characterisation and reactivity of carbenes, particularly N-heterocyclic carbenes (NHCs), and anionic-functionalised NHC ligands is discussed. The synthesis and reactivity of s-block, Group three and fblock NHC complexes is reviewed. The synthesis of the alcohol-functionalised unsaturated imidazolium proligand, [H2L]I [H2L = HOCMe2CH2(1-CH{NCHCHNiPr})], is extended to saturated imidazolinium analogues, [H2LR]X, [HOCMe2CH2(1-CH{NCH2CH2NR})]X (R = iPr, abbreviated to P; R = Mes, abbreviated to M; R = Dipp, abbreviated to D, X = Cl, I). Mono-deprotonation results in the isolation of bicyclic imidazolidines HLR, which can be ring-opened and silylated by treatment with Me3SiI, to afford [HLR, OSiMe3]I, R = iPr and Mes. Further deprotonation of HLR with MN"2 (M = Mg, Zn; N" = N(SiMe3)2) affords LRMN" (M = Mg and Zn) and ZnLR 2. These complexes proved active for the polymerisation of raclactide at room temperature without the need for an initiator. The third chapter focuses on cerium chemistry. Repetition of the literature synthesis of CeIV tert-butoxide compounds affords the unsolvated Ce(OtBu)4 and also the cluster Ce3(OtBu)11. Treatment of Ce(OtBu)4 with HL did not yield a CeIV-NHC complex, but one bearing a tethered imidazolium group, (OtBu)3Ce( -OtBu)2( -HL)Ce(OtBu)3. The synthesis of a CeIII-NHC complex, CeL3, and the oxidation of this forms an unprecedented CeIV-NHC complex, CeL4, via ligand redistribution; the complex contains two bidentate ligands and two alkoxide-tethered free NHC groups. Functionalisation of the free NHCs with boranes affords the adducts Ce(L)2(L-B)2, where B = BH3 or 9-BBN (9-Borabicyclo[3.3.1]nonane). A number of cerium complexes of the saturated-backbone NHC, LR, LRCeN"2 and LR 2CeN", have been synthesised and their oxidation chemistry and reactivity investigated. The final chapter contains an NMR study of the synthesis of a series of yttrium LR adducts, LP xYN"(3-x) (x = 1, 2 or 3), and of the synthesis of uranium complexes LRUN"2, R = Mes or Dipp, including a range of small molecule reaction chemistry. The uranyl NHC complexes, UO2LR 2, R = Mes or Dipp, have also been synthesised and characterised; these possess very high frequency carbene carbon chemical shifts.
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Kirkman, Joseph. "Synthesis of Heterocyclic C-Nucleoside Mimics." Thesis, University of Exeter, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531679.
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Jamalis, Joazaizulfazli. "Synthesis of heterocyclic containing oxygen compounds." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529847.
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O'Keefe, Brendan J. "Synthesis and Complexes of Heterocyclic Legends." Thesis, University of Canterbury. Chemistry, 1999. http://hdl.handle.net/10092/5795.
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Twenty nine new nitrogen-containing heterocyclic ligands have been prepared, and characterised. The ligands all contain a central arene core, to which are appended two or more heterocycles via spacer groups. Benzene, naphthalene, biphenyl, binaphthalene or triphenylene has been used as the central arene core, while the heterocycles used are pyridine, quinoline, 1 ,2,4-triazole, and benzotriazole.
The coordination chemistry of the majority of these ligands has been investigated by their reactions with transition metals with the aim of constructing metallosupramolecular architectures. Such assemblies are constructed using the coordination bond as the major intermolecular interaction, as well as weaker secondary interactions including π-π stacking interactions and hydrogen bonds.
The cyclopalladation chemistry some of these ligands, and of five previously prepared ligands, has also been investigated. In particular, a number of doubly palladated compounds containing six-membered chelate rings have been prepared. Such cyclopalladation reactions have been shown to be reversible. This, coupled with the appropriate reaction conditions, has allowed the regiochemistry of the products of the cyclopalladation reaction to be controlled in certain systems.
Techniques used to characterise the ligands and complexes include NMR spectroscopy, mass spectrometry, elemental analysis, and X-ray crystallography. The X-ray crystal structures of thirty-six complexes have been accurately determined, and the structures of two further complexes have been determined with less accuracy. The variety of ligands resulted in the preparation of a range of complexes of diverse structural types. The structures determined include one- and two-dimensional coordination polymers, a triple helicate, macrocycles, chelate complexes and supramolecular boxes.
The triple helicate is the first constructed from trigonal metal termini. The polymers include a molecular ladder that is the first to contain a ligand as the T-connector and metals as the linear connectors.
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Richardson, Christopher. "Synthesis and Complexes of Heterocyclic Ligands." Thesis, University of Canterbury. Chemistry, 1999. http://hdl.handle.net/10092/5801.
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The coordination chemistry of twenty chelating heterocyclic ligands, seven of which are new, is described. These ligands all contain heterocyclic ring systems that have previously received little attention in the literature. The specific ring systems involved are benzoxazoles, benzisoxazoles, benzothiazoles, benzotriazoles, 1,2,4- and 1,2,5- heterodiazoles, and the 1,4,2,5-dioxadiazene systems.
Many of the complexes synthesised are of ruthenium(II). These include monoruthenium complexes of the type [Ru(bpy)2(L)] 2+, homodinuclear complexes {[(bpy)2Ru(µ-BL)Ru(bpy2)4+ with µ-BL representing a doubly bidentate bridging ligand} as well as heterodinuclear ruthenium/palladium and ruthenium/platinum {[(bpy)2Ru(µ-BL)MCl2]2+ with M = Pd/Pt} complexes.
Also investigated are the coordination and supramolecular chemistry of many of the ligands with palladium(II), silver(I) and copper(II) metal ions. The X-ray crystal structures of five ligands and twenty complexes are described. An unexpected, previously unreported, heterocyclic transformation mediated by the Ru(bpy)22+ cation is also reported.
A combination of multinuclear NMR, UV-visible spectroscopy, cyclic voltammetry and X-ray crystallography has been used to study the nature of the metal-ligand and metal-metal interactions in the complexes produced.