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Dissertations / Theses on the topic 'Polycyclic'

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Published: 4 June 2021
Last updated: 2 February 2022

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1

Reginato, Nada McGlinchey Michael J. "Polycyclic compounds of manganese /." *McMaster only, 2003.

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2

Edwards, W. D. "Synthesis of polycyclic orthoamides." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370413.

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3

Tian, Zhenjiao. "Oxidation and Reduction Process for Polycyclic Aromatic Hydrocarbons and Nitrated Polycyclic Aromatic Hydrocarbons." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1228333650.

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4

Freeman, David John. "Polycyclic aromatic compounds in flames." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308234.

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5

Billington, Helen. "Novel approaches to polycyclic heterocycles." Thesis, University of Liverpool, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272632.

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6

Williams, David Alan John. "Radical approaches toward polycyclic alkaloids." Thesis, University of York, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323499.

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7

Crofts, Gavin Andrew. "Polycyclic peptides as host molecules." Thesis, University of York, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304170.

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8

Crowley, Colin. "Fullerenes from polycyclic aromatic hydrocarbons." Thesis, University of Sussex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360582.

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9

Houlsby, Ian. "Asymmetric syntheses of polycyclic amines." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:7c73384d-da09-41ee-b1fc-4509dd20aaf8.

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This thesis centers on the asymmetric synthesis of polycyclic amines, focussing on three distinct classes of polycyclic alkaloid natural products. The work aims to use common methodology of lithium amide conjugate additions as the source of asymmetry in all cases, and for each product class a single strategy is used to synthesise a variety compounds. Chapter 1 describes the importance of the synthesis of polycyclic alkaloids, highlighting three classes of compounds and documenting prior synthetic strategies. The classes discussed are: the Hancock alkaloids, hydroxymethyl-substituted azabicycles, and the tetraponerine alkaloids. Chapter 2 describes two separate synthetic strategies towards the Hancock alkaloid (-)-cuspareine, one using a benzyne mediated cyclisation and one a Buchwald-Hartwig cyclisation. The Buchwald-Hartwig methodology was also applied in the synthesis of two more Hancock alkaloids (-)-galipinine and (-)-galipeine; the synthesis of (-)-galipeine led to a reassignment of the structure of the natural product. Chapter 3 describes work in the synthesis of four [x.y.0]-azabicycles with differing in ring sizes (x, y = 3, 4). The strategy employs sequential SN2-like ring-closing reactions to form the bicyclic structures where pyrrolizidine, indolizidine and quinolizidine scaffolds can be accessed. Amongst the products are two natural alkaloids, (-)-lupinine and (+)-isoretronecanol. Chapter 4 describes the synthesis of all eight tetraponerine alkaloids T1-8. Two sequential lithium amide conjugate addition reactions allow for the synthesis of the differing ring-sizes and diastereoisomers displayed by the eight alkaloids. Ring-closing metathesis and diamine condensation with 4-bromobutanal provide the ring-closing steps in the syntheses. Chapter 5 contains full experimental procedures and characterisation data for all compounds synthesised in Chapters 2-4.
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10

Ren, Chien-Tai. "Synthesis of Polycyclic "Cage" Molecules." Thesis, University of North Texas, 1989. https://digital.library.unt.edu/ark:/67531/metadc500575/.

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The synthesis of a novel, cage spiro-oxetane was carried out. Pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecane-8- one (PCUD-8-one) undergoes one-carbon homologation to a mixture of endo- and exo- PCUD-carboxaldehydes which then are converted into 8,8-bis(hydroxymethyl)PCUD. The monotosylate obtained via reaction of 8,8- bis(hydroxymethyl)PCUD with tosyl chloride(1 equivalent) reacts with sodium hydride to afford the corresponding spiro-oxetane via intramolecular Williamson reaction. Six new substituted heptacyclo[6.6.0.0^2,6.0^3,13.0^4,11. 0^5,9.0^10,14]tetradecanes (HCTD) were synthesized. These compounds will be used as substrates in a photoelectron spectroscopic study. The ring-expansion reaction of PCUD-8-one with ethyl diazoacetate in the presence of BF_3:OEt_2 was performed. The major product was converted into an alcohol, and the structure of the 3,5-dinitrobenzoate of this alcohol was elucidated by single crystal x-ray structural analysis.
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11

Jones, David G. "Polycyclic monoids and their generalisations." Thesis, Heriot-Watt University, 2011. http://hdl.handle.net/10399/2473.

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12

Wang, Yanjun. "The Synthesis and Chemistry of Polyciclic Cage Compounds." Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc278447/.

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Chapter I describes the synthesis of a trishomocubyl helical tubuland diol and some aspects of its inclusion chemistry. Thus, all three isomers of 4,7-dimethylpentacyclo[6.3.0.0^2,6.0^3,10.0^5,9]undecane-4,7-diol have been prepared and their X-ray structures have been determined. The syn,syn-isomer crystallizes in a double-stranded hydrogen-bonded lattice, while anti,syn-isomer forms a hydrogen-bonded layer lattice. In contrast, the anti,anti-isomer is a new member of the helical tubuland diol host family; its crystal lattice consists of parallel canals with a trefoil-shaped cross-section of area 25.4 Å^2. Chapter II describes the synthesis of new molecular clefts. These molecular clefts have been synthesized via base-promoted reactions of 3,6-diaryl-l,2,4,5-tetrazines with tetracyclo[6.3.0.0^4,11.0^5,9]undecane-3,6-dione and with tricyclo[6.3.0.0^2,6]undecane-3,11-dione, respectively. Compounds of this type are of interest as a potential new class of host molecules for use in host-guest complexation studies. Chapter III reports the synthesis of stereospecifically deuterated spiro(oxetane-3,8'-pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecanes) and their acid-promoted ring opening and concomitant rearrangements. The deuterium-containing reaction products have been characterized via analysis of their NMR and mass spectra. The results strongly suggest that intramolecular 1,5-hydride shifts provide an important pathway through which the acid promoted rearrangements occur. Chapter IV reports the oxidation of heptacyclo-[6.6.0.0^2,6.0^3,13.0^4,11.0^5,9.0^10,14] tetradecane (HCTD) via application of Barton's "GoAgg" systems. The products have been characterized by NMR and mass spectral analysis. Under GoAgg^v conditions, oxidation of HCTD proceeds to afford heptacyclo [6.6.0.0^2,6.0^3,13.0^4,11.0^5,9.0^10,14]tetradecan-7-one in 1% yield.
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13

Rey, Carrizo Matías. "New polycyclic amines with biological activity." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/285111.

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Influenza is a major health problem worldwide, as the periodic pandemics of the 20th century have highlighted. Some countermeasures have been developed and have indeed diminish the devastating effects of the disease, such as modern health care, vaccination and novel medicines. Yet, the threat of a recombinant mutant virus that could affect millions of people and the recently discovered resistance of some virus strains to the current available treatments, render the need for new ways of fighting influenza A virus urgent. In the present dissertation we have taken amantadine as a model, an antiviral drug in disuse at the moment due to the appearance of resistant strains, that targets a viral proton channel named M2. Thus, we have synthesized and evaluated several polycyclic amines as potential wild-type M2 channel blockers and amantadine-resistant mutants, like V27A, as well. We have succeeded in the obtention of highly potent wild-type and V27A inhibitors and most remarkable, some of them exhibited a dual activity on both M2 channels. Noteworthy, among the prepared compounds, a polycyclic guanidine presented the higher activity ever recorded against the V27A mutant. Again working with polycyclic molecules but from a more theoretical point of view, the monomer, dimer and dihydrodimer of a highly strained pyramidalized alkene were synthesized and fully characterized. Importantly, the dimer featured four cyclohexanes in a frozen boat conformation and possessed hydrogen flagpole interactions that were relevant to theoretical organic chemists.
La grip presenta un greu problema arreu del món, com les pandèmies del segle XX han demostrat. S’han pres algunes mesures per lluitar-hi que han realment disminuït els efectes devastadors de la malaltia, com son la hospitalització moderna, la vacunació i les noves medicines. Tot i així, l’amenaça d’un virus recombinant mutant que pugui afectar a milions de persones i la recentment descoberta resistència d’algunes soques del virus als tractaments actuals, han provocat que la necessitat per a noves maneres de lluitar contra la grip A sigui urgent. En la present Tesi, hem pres amantadina com a model, un medicament antiviral actualment en desús degut a l’aparició de soques resistents, que té com a diana un canal de protons del virus anomenat M2. Així doncs, hem sintetitzat i avaluat diverses amines policícliques com a potencials blocadors del canal salvatge M2 i mutants resistents a amantadine, com el V27A, també. Hem tingut èxit en l’obtenció de potents inhibidors del canal salvatge i del V27A i lo més destacable és que alguns han mostrat una activitat dual en ambos canals M2. Cap remarcar que, entre els compostos preparats,una guanidina policíclica va presentar l’activitat més alta mai enregistrada contra el mutant V27A. Seguint amb les molècules policícliques però des d’un punt de vista més teòric, el monomer, dimer i dihidrodimer de un alqué altament piramidalitzat van ser sintetitzats i completament caracteritzats. Cal subratllar que, el dimer posseïa quatre ciclohexans en conformació bot congelat i mostrava interaccions entre els hidrògens flagpole que eren rellevants per als químics orgànics teòrics.
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14

Wu, Tao. "Synthetic studies on polycyclic indole alkaloids." [Ames, Iowa : Iowa State University], 2006.

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15

Safinowski, Michael. "Anaerobic biodegradation of polycyclic aromatic hydrocarbons." kostenfrei, 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=97648627X.

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16

Robertson, Charles Ray. "Chemistry towards curved polycyclic aromatic hydrocarbons." abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1438911.

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17

Wanene, Wilson Kamau. "Toward curved polycyclic aromatic hydrocarbons (PAHs)." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1445914.

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18

Sinanan, Shavak. "Algorithms for polycyclic-by-finite groups." Thesis, University of Warwick, 2011. http://wrap.warwick.ac.uk/49186/.

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A set of fundamental algorithms for computing with polycyclic-by-finite groups is presented here. Polycyclic-by-finite groups arise naturally in a number of contexts; for example, as automorphism groups of large finite soluble groups, as quotients of finitely presented groups, and as extensions of modules by groups. No existing mode of representation is suitable for these groups, since they will typically not have a convenient faithful permutation representation. A mixed mode is used to represent elements of such a group; utilising a polycyclic presentation or a power-conjugate presentation for the elements of the normal subgroup, and a permutation representation for the elements of the quotient.
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19

Close, Marjory. "The chemistry of polycyclic #omega#hydroxylactams." Thesis, University of Wolverhampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359669.

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20

Owens, K. A. "Polycyclic crown ethers incorporating cyclophane units." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370864.

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21

Gleisner, Florian Hans. "Bacterial degradation of polycyclic aromatic hydrocarbons." Thesis, University of York, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247752.

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22

Tyszka, Joanna Helen Margaret. "Towards the synthesis of polycyclic peptides." Thesis, University of York, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282302.

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23

Peters, Andrew John. "Polycyclic aromatic hydrocarbons in seasonal snowcover." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315520.

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24

Sritongkam, Pornpimol. "Electrochemical measurement of polycyclic aromatic hydrocarbons." Thesis, Cranfield University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274039.

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25

Tucker, Sheryl A. (Sheryl Ann). "Spectroscopic Properties of Polycyclic Aromatic Compounds." Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc278682/.

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The fluorescence spectrum of many polycyclic aromatic compounds (PACs) depends upon solvent polarity. The emission spectrum of PAC monomers consists of several major vibronic bands labeled I, II, etc., in progressive order. Emission intensity enhancement of select bands is observed in polar solvents.
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26

Ward, Collin P. "Direct and Indirect Photochemical Degradation of Two Polycyclic Musk Fragrances and Two Polycyclic Aromatic Hydrocarbons in Natural Waters." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275577426.

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27

Ouellette, Mélanie. "Gas-phase Ion Chemistry of Hydroxy and Amino-substituted Interstellar Polycyclic Aromatic Hydrocarbons and Protonated Polycyclic Aromatic Hydrocarbons." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31349.

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The gas-phase ion chemistry of hydroxyl- and amino-substituted polycyclic aromatic hydrocarbons (PAHs) and their protonated counterparts were studied using mass spectrometry. Ions were generated using an electron ionization (EI) source and the unimolecular chemistry of metastable ions was studied by performing mass-analysed ion kinetic energy spectrometry (MIKES) experiments with a magnetic sector tandem mass spectrometer. Collision-induced dissociation (CID) experiments were used in conjunction with MIKES experiments to determine ion structure. The ten molecules studied were: 1-naphthol, 2-naphthol, 1-naphthylamine, 2-naphthylamine, 1-aminoanthracene, 2-aminoanthracene, 1-phenanthrol, 9-phenanthrol, 1-hydroxypyrene and 1-aminopyrene. Since it is believed that larger PAHs, on the order of more than 50 carbon atoms, populate the interstellar medium, the goal of this study was to attempt to extrapolate the results from smaller systems to larger ones. The trends found include: hydroxy-substituted PAH radical cations lose carbon monoxide spontaneously and amino-substituted PAH radical cations lose HCN. Mechanisms for both processes are proposed, and it appears from the present results that this process should extrapolate to larger PAHs. Another trend found was that all the remaining fragment ions were always a closed ring. Protonated amino-substituted PAHs were generated by electrospray ionization using a quadruple time-of-flight mass spectrometer. By protonating 1-naphthol and 2-naphthol using methane in the high-pressure EI source, it was found that they lost exclusively H2O. As for 2-naphthylamine, 1-aminoanthracene and 2-aminoanthracene, it was found that 2-naphthylamine lost NH3 and a hydrogen atom, NH3being the dominant channel. However, as the ion size 3 increases, the hydrogen-loss channel became the dominant channel. This means that larger PAHs will likely lose exclusively a hydrogen atom to reform the parent radical cation.
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28

Labib, Sarah. "Utility of Toxicogenomics Tools for the Toxicological Assessment of Polycyclic Aromatic Hydrocarbons and Complex Polycyclic Aromatic Hydrocarbon Mixtures." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35342.

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Human exposures to polycyclic aromatic hydrocarbons (PAHs) occur as components of complex mixtures. Evaluations of health risks posed by complex mixtures containing PAHs rely on the toxicological knowledge of prioritized PAH mixture components, assuming that these PAHs share a common mode of action and that the sum of the contributions of these PAHs equals the toxic potency of the mixture (i.e., additivity). Traditional toxicity testing methods emphasizing apical endpoints have had limited success at evaluating the validity of these assumptions. Toxicogenomic tools that are able to rapidly generate toxicologically-relevant and mechanistic information have gained acceptance in the regulatory arena for individual chemicals; however, the applicability of these tools for chemical mixtures has been inadequately addressed. This thesis used toxicogenomic tools to (1) improve the understanding of mechanisms underlying the adverse, toxicological responses induced by individual PAHs and (2) evaluate the contention that transcriptional profiles and pathway information can be used to critically examine interactions between individual PAHs in PAH-containing mixtures, and the assumption of additivity. Microarrays were used to profile gene expression changes (transcriptomes) in forestomach, liver, and lung tissues (targets of PAH exposure) from mice orally exposed to three doses of eight individual PAHs, two defined PAH mixtures, and one complex PAH-containing mixture (coal tar). The results revealed that each PAH induced transcriptional changes that were significantly associated with several pathways implicated in carcinogenesis. However, despite a uniform ability to induce DNA damage (i.e., DNA adducts), mutations, and increases in enzyme activity, the pathways differ across PAHs and tissues. A novel strategy that employs single-PAH transcriptome data to models of additivity revealed that the assumption of additivity in PAH mixtures is valid at the pathway level; however, the independent action model of additivity yielded better estimates compared to concentration addition (used in human health risk assessment of PAH mixtures) or generalized concentration addition. Additionally, predicted and observed coal tar-induced transcriptional benchmark doses were comparable to those derived from previously published coal tar-induced murine lung tumour incidence data. Overall, this thesis demonstrates the utility of toxicogenomic data to expand the current understanding regarding the toxic potential of individual PAHs and PAH-containing complex mixtures.
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29

Warner, Stephanie D. "Photochemical degradation of selected polycyclic aromatic compounds." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84446.

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Polycyclic aromatic hydrocarbons and many of their derivatives are considered to be ubiquitous environmental pollutants, which often exhibit mutagenic and/or carcinogenic activity. In the atmosphere, photolysis is generally considered to be the dominant degradation pathway for these pollutants. The photochemical behaviours of benzo(a)pyrene, benzo(b)fluoranthene and benzo(k)fluoranthene have been examined in the laboratory. This study was complemented by an analysis of ambient air samples collected in the vicinity of a Horizontal Stud Soderberg aluminum smelter in Beauharnois, Quebec. Benzo(a)pyrene is much more reactive in the presence of light when compared to the fluoranthene compounds. The products were identified as the 1,6-, 3,6- and 6,12-benzo(a)pyrenediones. An analysis of the ambient air samples revealed the prevalence of benzo(b)fluoranthene in the emissions from the aluminum smelter. Its relatively high abundance and resistance to degradation indicates that it will be a suitable indicator to represent total polycyclic aromatic hydrocarbon levels at the smelter. The photochemical behaviour of a series of nitropolycyclic aromatic hydrocarbons has also been investigated. The photoreactivity of these compounds in solution and adsorbed onto a surface has previously been associated with the torsion angle of the nitro group with respect to the aromatic moiety. Initially, through a combination of spectroscopic techniques and semi-empirical calculations, the orientation of the nitro group in each compound was determined. Solution studies were inconclusive in determining the role of the torsion angle of the nitro group in influencing the photochemical degradation. However, when the compounds were adsorbed onto a surface, no relationship could be established between photoreactivity and the orientation. The stability of these compounds was also examined during the sampling process. In an effort to further examine the relationship between th
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30

Torres, Costa Eva. "Synthesis of polycyclic compounds with antiviral activity." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/124040.

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Research for new antivirals to treat Influenza A virus infections has gained importance during this last decade due to the imminent danger of an Influenza pandemic. For some years, several new strains of this virus have appeared worldwide causing small outbreaks with a notable relevance, for example the ‘avian flu’ (H5N1 in 2007; H7N9 in 2012) and ‘swine flu’ (H1N1 in 2009), that have triggered the assumption that a new pandemic is coming. There are several strategies to treat an Influenza A virus infection targeting some of its surface proteins. In this Thesis, several compounds inhibiting the M2 channel of the virus are designed, synthesized and evaluated. Our approach is based on the synthesis of amantadine’s analogues by ring expansion, contraction and rearrangement. Amantadine is a drug already approved by the FDA for the treatment of Influenza A virus and it is known to target the M2 channel. Although it is no longer in use, because the FDA has recommended against its use, due to the appearance of resistance, it possessed good activity and an acceptable pharmacological behaviour. Our main goal was to synthesize an analogue of amantadine that was able to overcome the resistant virus and provide a new therapeutic alternative to the already marketed neuraminidase inhibitors such as Oseltamivir and Zanamivir. Importantly, we took advantage of the wide expertise of our research group in synthesizing polycyclic compounds to start a new research field that was based on the application of these optimized synthetic routes to the Medicinal chemistry. We established some external collaboration in order to set up the milestones and to build the rationale of the current project. These new collaborations are the following: - Prof. Lieve Naesens research group in the Rega Institute for Medical Research in Leuven, Belgium. This group of virologist made the plaque reduction assays and the study of the mutants to establish the mechanism of action of the tested compounds. - Lawrence H. Pinto research group of the Northwestern University, Evanston, Illinois, USA. This group of biochemist made the patch clamp assay to check if our compounds targeted the M2 channel. - Prof. Javier Luque of Universitat de Barcelona, Barcelona, España. This group made the docking and molecular dynamics of our compounds. In the following figures, the general structures of the compounds synthesized in the current Thesis are shown. Several of them showing an outstanding activity that allowed us to publish in the most important journals of the Medicinal Chemistry field: It it worth to mention that, several compounds have shown better activity than the reference compound, Amantadine. The most distinguished compounds are the following: Compound 1, 2 and 3 showed a superior activity against H1N1 strain in the cell culture assay while being almost inactive in the patch clamp assay. Prof. Lieve Naesen’s research group tried to identify the mechanism of action of these compounds selecting the mutants of hemagglutinin under the pressure of our compounds, revealing that this protein was the target of the first cluster of molecules. Compound 4 and 5 showed an outstanding activity against the wild-type and V27A M2 channels of influenza A virus. Taken together, all of these results show that tuning the polycyclic scaffold of amantadine could be the way to overcome the already stated resistance. A second part of this current Thesis consisted in a collection of compounds that have activity against vaccinia virus. These compounds are analogues of Tecovirimat®, a compound that it is currently in phase III clinical trials. When we started this project, we wanted to explore the impact in the EC50 of changing the polycyclic scaffold of the Tecovirimat® molecule, a common tool used in Medicinal Chemistry. We synthesized nearly 40 compounds and we obtained activities similar to Tecovirimat®, although none of our molecules was better than the reference compound.
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31

Lu, Yingzi. "Polycyclic and oligocyclic phosphorus-nitrogen ring systems." [S.l.] : [s.n.], 2006. http://www.digibib.tu-bs.de/?docid=00005216.

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32

Pizzul, Leticia. "Degradation of polycyclic aromatic hydrocarbons by actinomycetes /." Uppsala : Department of Microbiology, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200650.pdf.

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33

Rogers, Joseph Nathan. "Biomimetic studies towards the polycyclic diterpene bielschowskysin." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/13999/.

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Thesis describes synthetic studies directed towards evaluating the biosynthetic relationships between several novel polycyclic diterpenes, including bielschowskysin 1, verrillin 2, plumarellide 3 and intricarene 4, and their probable furanobutenolide -based cembrane precursors, e.g. bipinnatin J (5) and bipinnatin G (6). These interesting natural products have all been isolated from marine corals in recent years. The Introduction describes a general overview of biologically active compounds isolated from natural sources, followed by the isolation, structure and biological profile of the aforementioned marine natural products. The Discussion section introduces the family of furanobutenolide - based cembrane natural products and then discusses the structures of bielschowskysin 1, verrillin 2, plumarellide 3 and intricarene 4 and their proposed biogenetic origins from simple furanocembranes via transannular pericyclic cycloaddition processes. A synthetic study towards the model bielschowskysin structures 106 and 132 from rubifolide analogues, i.e. 102 and 125 is then described. Difficulties with the stabilities of various substrates led to abandonment of this route, but an alternative strategy produced the 14-membered furanocembrane structure 142 which lacked a delta11,12-alkene bond. Further manipulation of 142 into the modified bielschowskysin structure 125 could not be achieved, due to the dearth of material. The oxidation chemistry of 2-alkenylfurans was next studied. Model studies established that treatment of the alkenylfuran 162 with peroxy reagents led to the Zdienedione 163. When 163 was left in the presence of p-TSA in THF-H20 it was first converted into the beta-hydroxyketone 165 and then into the vicinal diol 178, presumably via the transient enol ether species 166. In complementary studies, treatment of the Z-dienedione 163 with K2C03 in THF-H20 led to the 4-hydroxycyclopent-2-enone 193 (53%), and isomerisation in the presence of iodine gave the corresponding E-isomer 194 (90%). These observations may have significance for the origins of coralloidolide F (195) and the macrocyclic Edienedione 196 from furanocembrane precursors in corals. A brief review of the syntheses of furanobutenolide - based cembranes is presented and then two synthetic approaches towards deoxybipinnatin G (188b/ 188e), using Aldol/Stille/Nozaki-Hiyama-Kishi (NHK) and ring-closing metathesis (RCM)/StilieINHK reactions, are presented. The RCM/StillelNHK approach produced the macrocyclic precursor 275b which, unfortunately, upon exposure to CrCh in THF, produced the acyclic intermediate 318. In contemporaneous studies, attempts were made to form the furanobutenolide - based cembrane bis-deoxylopholide 319 en route to plumarellide 3, via a ReM approach. Unfortunately, exposure of the vinyl furan 322 to Grubbs 2nd generation catalyst in refluxing DCM only led to the phenylvinylfuran 338 and to the dimer 339. In a separate study, treatment of isoepilophodione B (159), derived from bipinnatin J (5) via rubifolide 49, with p- TSA in THF-H20 led to the novel and unusual 19-hydroxyrubifolide 353, presumably via the enol ether intermediate 354 and allylic transposition. The Experimental section contains full details of the preparative work carried out, and collects together spectroscopic and analytical data for all the new compounds described.
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34

Candian, Alessandra. "Polycyclic aromatic hydrocarbons in the interstellar medium." Thesis, University of Nottingham, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604895.

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The Unidentified Infrared (UIR) bands are a family of emission features seen in dusty objects, which are generally attributed to IR fluorescence of small (~ 50 C-atoms) polycyclic aromatic hydrocarbon (PAH) molecules. However, no specific PAH has so far been identified. The spatial distribution of 3.3 p,m PAH emission in the inner region of the Red Rectangle nebula is studied using an Integral Field spectroscopy technique. The presence of two components at 3.28 and 3.30 p,m with different spatial distributions, originally proposed by Song et al. (2003, 2007) is supported by these data. This implies the presence of two classes of 3.3 p,m band carrier with peak wavelength separation of ",0.02 p,m. From comparison of the 3.3 p,m observations with laboratory and theoretical spectra for a range of PAH molecules it is inferred that the 3.28 p,m and 3.30 p,m components arise from 'bay' and 'non-bay' hydrogen sites, respectively, on the periphery of neutral PAHs. The vibrational spectrum of a large number of PAH molecules are investigated with Density Functional Theory (DFT) calculations to find possible trends which may help in the identification of specific PAHs. It has been found that for acenes (single row), the position of the solo out-of-plane bending mode moves to shorter wavelength with increase number of carbon atoms. A similar behaviour holds also for 2-rows, 3-rows and large compact PAH molecules. Pericondensed and catacondensed PAHs with functional groups are investigated to assess their contribution to the unidentified 21 p,m feature, found in carbon-rich environments. They are unlikely to be responsible for the feature. The results of DFT calculations for large, solo-containing PAHs are then used to model Abstract 4 the asymmetric profile of the 11.2 p,m feature. The IR emission mechanism is taken into account, together with the effects of the DV radiation field in different sources; the temperature dependence of the solo out-of-plane bending mode and position are also considered, using state-of-the-art experimental data. It is found that the model reproduces very well the shape and the val1ations of the 11.2 p,m band in a few environments, supporting the idea that these variations are due to different mass distributions of PAHs, rather than anharmonicity. A similar model is then applied to acenes, which appear to contribute most of the intensity of the 11.0 p,m feature. High-resolution long-slit spectroscopic observations of the 11.2 p,m band in two PNe (NGC 7027 and BD+30° 3639) and in a PDR (The Orion Bar), in a search for fine stmcture have been carried out. While the presence of fine structure cannot ruled out, changes in the 11.2 p,m feature along the Orion Bar, from the molecular cloud to the ionised region, is seen suggesting possible evolution of the carriers of the feature. ..
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35

Hussain, Sabir. "Polycyclic receptors for anion binding and transport." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547832.

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36

Ciochina, Roxana. "STUDIES TOWARD SYNTHESIS OF POLYCYCLIC POLYPRENYLATED ACYLPHLOROGLUCINOLS." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_diss/291.

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Polycyclic polyprenylated acylphloroglucinols (PPAPs) are a class of compounds that reveal intriguing biological activities and interesting and challenging chemical structures. These products are claimed to possess antioxidant, antiviral, and antimitotic properties. Increasing interest is related to their function in the CNS as modulators of neurotransmitters associated to neuronal damaging and depression. All these features make PPAPs targets for synthesis. We decided to focus our own initial efforts in this area on the type A PPAP, nemorosone because we thought that its fairly simple structure relative to other PPAPs would present fewer hurdles as we developed our methodology.In the past decade many approaches to the synthesis of the bicyclo[3.3.1]nonane-2,4,9-trione structure of type A PPAPs have been reported, but only two total syntheses of any PPAP, garsubellin A by Shibasaki and Danishefsky, have been published recently, near the end of 2005. All approaches have relied on the ??,????-annulation of a three-carbon bridge onto a cyclohexanone, although the methods used to execute this annulation differ dramatically. The methods most often used to form the two new C–C bonds have involved classical carbonyl chemistry.We have developed a short and efficient synthetic approach to the bicyclo[3.3.1]nonane skeleton of the PPAPs that involves a novel three-carbon ??,????-annulation of a sterically hindered cyclic ??-keto ester with 3,3-diethoxypropyne. The alkynylation reaction permits the construction of the two contiguous quaternary centers of the PPAPs in reasonable yield and without complications from side reactions. We have also successfully applied a recently developed syn hydrosilylation to the very hindered product of this alkynylation reaction. Our methodology received positive feedback already, and we see this total synthesis of nemorone as an ideal platform for the implementation of new synthetic methodologies.
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37

Engel, García Paloma. "Novel coupling reactions for complex polycyclic ethers." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4339/.

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Development of cascade RCM reactions, where two different approaches are proposed. The first route involves a ruthenium-catalysed enyne RCM reaction, followed by a metallotropic [1,3]-shift and a final alkene RCM. The second route incorporates an enyne RCM reaction followed by direct alkene metathesis. These methodologies provide access to common bicyclic and tricyclic polyether skeletons such as those present in tamulamide, prymnesin, gambierol and maitotoxin, respectively. The second project is concerned with the synthesis of the C-G ring fragment of gambieric acid and the development of novel methodology for the formation of the seven membered E ring.
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38

Hempenstall, Francis. "Chemoenzymatic synthesis of polycyclic aromatics and derivatives." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287469.

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39

Smith, Michael John. "Bioremediation of polycyclic aromatic hydrocarbons in soil." Thesis, University of Kent, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242929.

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40

Hoban, T. J. "Polycyclic aromatic hydrocarbons in the Severn Estuary." Thesis, University of South Wales, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305737.

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41

Carter, Steven Robert. "The synthesis of polycyclic peptide host molecules." Thesis, University of York, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359259.

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42

Zindo, Frank T. "Polycyclic propargylamine derivatives as multifunctional neuroprotective agents." University of the Western Cape, 2018. http://hdl.handle.net/11394/6748.

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Philosophiae Doctor - PhD
The abnormal death of neurons in the central nervous system of individuals suffering from neurodegenerative diseases such as Parkinson’s disease, Alzheimer’s disease, Huntington’s disease and amyotrophic lateral sclerosis, takes place by an intrinsic cell suicide programme known as apoptosis. This process is triggered by several stimuli, and consists of numerous pathways and cascades which lead to the death of neuronal cells. It is this multifactorial nature of neurodegenerative diseases that has over the years seen many researchers develop compounds that may serve as multi-target directed ligands (MTDLs) which could potentially confer neuroprotection by acting simultaneously on different receptors and target sites implicated in neurodegeneration. This study was aimed at developing MTDLs that may serve as neuroprotective agents by simultaneously (a) inhibiting N-methyl D-aspartate receptors (NMDAR) and blocking L-type voltage gated calcium channels (VGCC) thus regulating the Ca2+ influx mediated excitotoxic process; (b) inhibiting the monoamine oxidase enzymes A and -B (MAO-A/B) thus allowing increase in dopamine levels in the central nervous system and reducing the levels of the highly oxidative products produced by the activity of these enzymes; (c) possessing anti-apoptotic activity to halt the neuronal cell death process. In designing the compounds we focused on the structures of rasagiline and selegiline, two well-known MAO-B inhibitors and proposed neuroprotective agents, and of NGP1-01, a known VGCC blocker and NMDAR antagonist. The first series of compounds (reported in research article 1, Chapter 3), comprised polycyclic propargylamine and acetylene derivatives. Compounds 12, 15 and 16 from this series showed promising VGCC and NMDA receptor channel inhibitory activity ranging from 18 % to 59 % in micromolar concentrations, and compared favourably to the reference compounds. In the MAO-B assay, compound 10 exhibited weak MAO-B inhibition of 73.32 % at 300 μM. The rest of the series showed little to no activity on these target sites, despite showing significant anti-apoptotic activity. This suggested the compounds in this series to be exhibiting their neuroprotective action through some other mechanism(s) unexplored in this study.
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43

Chen, Dongping. "Numerical investigation of polycyclic aromatic hydrocarbon clusters." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708341.

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44

Ball-Jones, Matthew Phillip. "Cascading cycloadditions for polycyclic sp³-rich architecture." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7986/.

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This thesis describes the formation of complex 3-dimensional polycyclic heterocycles via intramolecular Diels-Alder reactions of highly functionalised 4-aminooxazoles. The research presented discusses the advances made in the formation of alkene and alkyne tethered aminides alongside the synthesis of a range of 1,6- and 1,7- enynamides and the rapid transformation of such components into a densely functionalised core. The scope of this process, using both C-2 and C-5 dienophile-tethered oxazoles is discussed and the potential of 1,6-enynamides to undergo cycloisomerisation under gold-catalysis is unveiled. Mechanisms for both the cycloisomerisation and the oxazole formation are provided, with brief investigations into inner and outer sphere processes. The gold-catalysed formal (3+2)-dipolar cycloaddition of both aminides and dioxazoles with thioalkynes is also presented, with the production of a range of diversely functionalised 5-thiooxazoles. Preliminary investigations into the use of Bronsted acid catalysis for the synthesis of 4-thiooxazoles is discussed alongside mechanistic proposals.
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45

Harris, Katherine S. M. Massachusetts Institute of Technology. "Diversity of polycyclic triterpenoids in Rhodospirillum rubrum." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/58195.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 22-24).
Sedimentary rocks of all ages abound with geostable lipids of microbial origin, but many biomarkers lack known organismal sources and clear environmental contexts. Here we used Rhodospirillum rubrum, a metabolically versatile, genetically tractable c-Proteobacterium, to explore the diversity of its non-polar terpenoids as a function of growth condition and growth phase. We analyzed the nonpolar fraction of lipids extracted from R. rubrum grown under aerobic, anaerobic, heterotrophic and phototrophic conditions and detected a variety of bicyclic, tricyclic, tetracyclic and pentacyclic triterpenoids, derived from the enzymatic cyclization of squalene and produced in amounts comparable to diploptene. Identified compounds included bicyclic polypodatetraenes, malabaricatriene, euphadiene, adianane, and fernene. Prior to this work, malabaricatriene was an "orphan" biomarker suspected to have a microbial origin, yet it lacked a proven source. We observed similar patterns of polycyclic terpenoids in other hopanoid-producing c-proteobacteria, including Zymomonas mobilis, Rhodopseudomonas palustris, and Rhodomicrobium vannielii. The presence and relative abundance of polycyclic triterpenoids in R. rubrum varied with the growth stage (exponential versus early stationary phase) and growth condition (photoheterotrophic versus photoautotrophic growth). Since R. rubrum's genome contains a single squalene-hopene cyclase gene, the array of triterpenoids produced by it and other c-proteobacteria likely evolves from this enzyme performing low-fidelity cyclization. The observed diversity of sedimentary triterpenoids might therefore result from a select few squalene-hopene cyclase enzymes operating with varying specificity under a range of physiological and environmental conditions, rather than reflecting a great diversity of squalene-hopene cyclases.
by Katherine Harris.
S.M.
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46

Richter, Marcus, Karl Sebastian Schellhammer, Peter Machata, Gianaurelio Cuniberti, Alexey Popov, Frank Ortmann, Reinhard Berger, Klaus Müllen, and Xinliang Feng. "Polycyclic heteroaromatic hydrocarbons containing a benzoisoindole core." Royal Society of Chemistry, 2017. https://tud.qucosa.de/id/qucosa%3A36567.

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By the combination of 9a-azaphenalene and a perpendicularly oriented acene, we have synthesized three derivatives of a series of novel, fully-conjugated nitrogen-containing polycyclic aromatic hydrocarbons (PAHs), namely [7,8]naphtho[2′,3′:1,2]indolizino[6,5,4,3-def]phenanthridine, with an acetylene triisopropylsilyl (TIPS), phenyl or benzothiophenyl substituent. Their optoelectronic properties were studied via UV-Vis-NIR absorption, fluorescence spectroscopy and cyclic voltammetry. In addition, in situ spectroelectrochemistry was performed to investigate the optical and magnetic properties of the mono-radical cation and anion by quasi-reversible oxidation and reduction of 11-(tert-butyl)-5,17-bis((triisopropylsilyl)ethynyl)[7,8]naphtho[2′,3′:1,2]indolizino[6,5,4,3-def]phenanthridine (1a). Theoretical modelling confirmed the predominately closed-shell electronic ground state with a weak diradical character depending on the geometry.
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47

Branan, Bruce Monroe. "The chemistry of polycyclic and spirocyclic compounds /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487849696968107.

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48

Richter, Marcus, Yubin Fu, Evgenia Dmitrieva, Jan J. Weigand, Alexej Popov, Reinhard Berger, Junzhi Liu, and Xinliang Feng. "Polycyclic Aromatic Hydrocarbon Containing A Pyrrolopyridazine Core." Wiley-VCH, 2019. https://tud.qucosa.de/id/qucosa%3A73140.

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Polycyclic aromatic azomethine ylide (PAMY) is a versatile building block for the bottom-up construction of unprecedented nitrogen-containing polycyclic aromatic hydrocarbons (N-PAHs). Here, we demonstrate the 1,3-dipolar cycloaddition between PAMY and 1,4-diphenylbut-2-yne-1,4-dione as well as the subsequent condensation reaction with hydrazine, which led to synthesis of unique N-PAHs with a phenyl-substituted pyrrolopyridazine core (PP-1 and PP-2). The molecular structures of pristine PP-1 and tert-butyl-substituted PP-2 were verified by NMR and mass spectroscopy. Moreover, the structure of PP-2 was unambiguously elucidated by X-ray single crystal analysis. The optoelectronic properties were investigated by solvent-dependent UV-Vis absorption and fluorescence emission spectroscopy as well as cyclic voltammetry. Additionally, the density functional theory (DFT) calculations exhibited a push-pull behavior for PP-1 and PP-2. Furthermore, the in situ EPR/UV-Vis-NIR spectroelectrochemistry allowed the detailed insight into the spectroscopic properties and spin distribution of radical cation species of PP-2.
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49

Liu, Junzhi, Ji Ma, Ke Zhang, Prince Ravat, Peter Machata, Stanislav Avdoshenko, Felix Hennersdorf, et al. "π-Extended and Curved Antiaromatic Polycyclic Hydrocarbons." ACS Publications, 2017. https://tud.qucosa.de/id/qucosa%3A36577.

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Synthesis of antiaromatic polycyclic hydrocarbons (PHs) is challenging because the high energy of their highest occupied molecular orbital and low energy of their lowest unoccupied molecular orbital cause them to be reactive and unstable. In this work, two large antiaromatic acene analogues, namely, cyclopenta[pqr]indeno[2,1,7-ijk]tetraphene (CIT, 1a) and cyclopenta[pqr]indeno[7,1,2-cde]picene (CIP, 1b), as well as a curved antiaromatic molecule with 48 πelectrons, dibenzo[a,c]diindeno[7,1,2-fgh:7′,1′,2′-mno]-phenanthro[9,10-k]tetraphene (DPT, 1c), are synthesized on the basis of the corona of indeno[1,2-b]fluorene. These three antiaromatic PHs possess a narrow energy gap down to 1.55 eV and exhibit high kinetic stability under ambient conditions. Moreover, these compounds display reversible electron transfer processes in both the cathodic and anodic regimes. Their cation and anion radicals are characterized by in situ vis−NIR absorption and electron paramagnetic resonance spectroelectrochemistry. The X-ray crystallographic analysis confirms that while CIP and CIT manifest planar structures, DPT shows a curved πconjugated carbon skeleton. The synthetic strategy starting from ortho-substituted benzene units to construct five-membered rings in this work provides a unique entry to novel pentagon-embedding or curved antiaromatic polycyclic hydrocarbons. In addition, besides the detailed chemical and physical investigations, microscale single-crystal fiber field-effect transistors were also fabricated.
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50

Brown, James S. "The chemistry of nickel on the edge of polycyclic aromatic hydrocarbons /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1422914.

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