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  • 1. Daikoku, S.
    et al.
    Pendrill, Robert
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kanie, Y.
    Ito, Y.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kanie, O.
    Synthesis and structural investigation of a series of mannose-containing oligosaccharides using mass spectrometry2018In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 16, no 2, p. 228-238Article in journal (Refereed)
    Abstract [en]

    A series of compounds associated with naturally occurring and biologically relevant glycans consisting of alpha-mannosides were prepared and analyzed using collision-induced dissociation (CID), energy-resolved mass spectrometry (ERMS), and H-1 nuclear magnetic resonance spectroscopy. The CID experiments of sodiated species of disaccharides and ERMS experiments revealed that the order of stability of mannosyl linkages was as follows: 6-linked > 4-linked >= 2-linked > 3-linked mannosyl residues. Analysis of linear trisaccharides revealed that the order observed in disaccharides could be applied to higher glycans. A branched trisaccharide showed a distinct dissociation pattern with two constituting disaccharide ions. The estimation of the content of this ion mixture was possible using the disaccharide spectra. The hydrolysis of mannose linkages at 3- and 6-positions in the branched trisaccharide revealed that the 3-linkage was cleaved twice as fast as the 6-linkage. It was observed that the solution-phase hydrolysis and gas-phase dissociation have similar energetics.

  • 2.
    Elgland, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Synthesis and application of β-configured [18/19F]FDGs: Novel prosthetic CuAAC click chemistry fluoroglycosylation tools for amyloid PET imaging and cancer theranostics2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Positron emission tomography (PET) is a non-invasive imaging method that renders three-dimensional images of tissue that selectively has taken up a radiolabelled organic compound, referred to as a radiotracer. This excellent technique provides clinicians with a tool to monitor disease progression and to evaluate how the patient respond to treatment. The by far most widely employed radiotracer in PET is called 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG), which is often referred to as the golden standard in PET. From a molecular perspective, [18F]FDG is an analogue of glucose where a hydroxyl group has been replaced with a radioactive fluorine atom (18F). It is well known that covalent attachment of carbohydrates (i.e., glycosylation) to biomolecules tend to improve their properties in the body, in terms of; improved pharmacokinetics, increased metabolic stability and faster clearance from blood and other non-specific tissue. It is therefore natural to pursuit the development of a [18F]fluoroglycosylation method where [18F]FDG is chemically conjugated to a ligand with high affinity for a given biological target (e.g., tumors or disease-associated protein aggregates).

    This thesis describes a novel [18F]fluoroglycosylation method that in a simple and general manner facilitate the conjugation of [18F]FDG to biological ligands using click chemistry. The utility of the developed [18F]fluoroglycosylation method is demonstrated by radiolabelling of curcumin, thus forming a tracer that may be employed for diagnosis of Alzheimer’s disease. Moreover, a set of oligothiophenes were fluoroglycosylated for potential diagnosis of Alzheimer’s disease but also for other much rarer protein misfolding diseases (e.g., Creutzfeldt-Jakob disease and systemic amyloidosis). In addition, the synthesis of a series of 19F-fluoroglycosylated porphyrins is described which exhibited promising properties not only to detect but also to treat melanoma cancer. Lastly, the synthesis of a set of 19F-fluorinated E-stilbenes, structurally based on the antioxidant resveratrol is presented. The E-stilbenes were evaluated for their capacity to spectrally distinguish between native and protofibrillar transthyretin in the pursuit of finding diagnostic markers for the rare but severe disease, transthyretin amyloidosis.

  • 3. Gisbert, Patricia
    et al.
    Trillo, Paz
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Organic Chemistry Dpt. and Instituto de Sintesis Organica (ISO).
    Pastor, Isidro M.
    Comparative Study of Catalytic Systems Formed by Palladium and Acyl-Substituted Imidazolium Salts2018In: CHEMISTRYSELECT, ISSN 2365-6549, Vol. 3, no 3, p. 887-893Article in journal (Refereed)
    Abstract [en]

    Amino amides, which are readily accessible from amino acids, were used in the preparation of both monoamido and diamido functionalized imidazolium salts in very straightforward protocols. Different catalytic systems formed with palladium(II) acetate and acyl functionalized imidazolium salts were tested in the Matsuda-Heck reaction. The comparative study revealed that the presence of one carbamoyl moiety in the N-heterocyclic carbene precursor is more beneficial during the catalytic process. Thus, better activity was observed with the catalytic system formed using 3-benzyl-1-(N-phenylcarbamoyl-methyl)imidazolium chloride in a 1:1 metal/ligand ratio. Moreover, this fact was evidenced by means of UV/vis studies.

  • 4.
    Hur, Deniz
    et al.
    Anadolu Univ, Turkey; Bionkit Co Ltd, Turkey.
    Say, Mehmet Girayhan
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Bionkit Co Ltd, Turkey.
    Diltemiz, Sibel E.
    Anadolu Univ, Turkey; Bionkit Co Ltd, Turkey.
    Duman, Fatma
    Anadolu Univ, Turkey.
    Ersoz, Arzu
    Anadolu Univ, Turkey; Bionkit Co Ltd, Turkey.
    Say, Ridvan
    Anadolu Univ, Turkey; Bionkit Co Ltd, Turkey.
    3D Micropatterned All-Flexible Microfluidic Platform for Microwave-Assisted Flow Organic Synthesis2018In: CHEMPLUSCHEM, ISSN 2192-6506, Vol. 83, no 1, p. 42-46Article in journal (Refereed)
    Abstract [en]

    A large-area, all-flexible, microwaveable polydimethoxysilane microfluidic reactor was fabricated by using a 3D printing system. The sacrificial microchannels were printed on polydimethoxysilane substrates by a direct ink writing method using water-soluble Pluronic F-127 ink and then encapsulated between polydimethoxysilane layers. The structure of micron-sized channels was analyzed by optical and electron microscopy techniques. The fabricated flexible microfluidic reactors were utilized for the acetylation of different amines under microwave irradiation to obtain acetamides in shorter reaction times and good yields by flow organic synthesis.

  • 5.
    Rabten, Wangchuk
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    The Use of N,P-Iridium and N,P-Palladium Complexes in Asymmetric Synthesis2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The work presented in this thesis concerns asymmetric catalysis using chiral N,P-ligands and iridium or palladium transition metals. The first part  (Chapters 2 and 3) highlights the N,P-iridium catalyzed asymmetric hydrogenation of 1,4-cyclohexadienes having functionalized or unfunctionalized substituents, including allylsilane side chains. A series of N,P-iridium catalysts were synthesized and screened on a number of cyclohexadienes. The developed N,P-iridium catalysts have provided excellent chemo-, regio- and enantioselectivity for most of the products obtained. For substrates having an allylsilane sidechain, the chiral cyclic allylsilane products were used to induce stereocontrol in a subsequent Hosomi-Sakurai reaction using TiCl4 as Lewis acid and aldehydes as electrophiles. The corresponding homoallylic alcohols were obtained in good to excellent diastereoselectivity. 

    The second part (Chapter 4) describes the N,P-iridium catalyzed asymmetric hydrogenation of various vinyl fluorides. A number of tri- and tetrasubstituted vinyl fluorides were synthesized and evaluated for the asymmetric hydrogenation. The corresponding saturated chiral fluoro compounds were obtained in very high enantioselectivity (up to 99% ee). The defluorination, usually known to occur under the catalytic hydrogenation conditions, were not observed for the majority of the substrates. 

    Finally, Chapter 5 describes the application of N,P-ligands in the asymmetric cycloisomerization of 1,6-enynes using a palladium precatalyst. The enantioselectivities for the products were found to depend both on the substrate as well as the hydrogen source. These developed catalytic reactions provide attractive methods to create multiple stereogenic centers in a molecule in relatively few steps from readily available starting materials.

  • 6.
    Revoju, Srikanth
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Molecular design, synthesis and performance evaluation of phenothiazine-based small molecules for efficient organic solar cells2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Photovoltaics offers one of the most promising routes to generate electricity in a clean way. As an emerging technology in photovoltaics, organic solar cells (OSC) have attracted a great deal of attention owing to their potential low-cost, lightweight, flexibility and solution processability. Although power conversion efficiencies above 12% have been achieved at this date, there is a great interest for new ideal materials to further improve the PCEs and address device durability, which are major concerns for the commercialization of this technology. The main objective of this thesis is to design and synthesize phenothiazine-based conjugate small molecules and explore their use as electron donor components in OSCs. Phenothiazine is a non-planar moiety with unusual “butterfly” type of geometry, which is known to reduce molecular aggregation and intermolecular excimer formation.

    In the first study of this thesis, a small molecule based on a cyano-arylenevinylene building block with deep HOMO level was prepared. Although a high open-circuit voltage of 1.0 V was achieved, the tendency of the small molecule to crystallize in the active layer at a higher temperature and with time hindered the attainment of an optimal phase morphology required for the achievement of a higher efficiency. In the second and third studies, phenothiazine was used as a π-system bridge and as a core unit to construct small molecules based on symmetric and asymmetric frameworks with varying terminal electron-withdrawing groups. The electron-withdrawing property of the terminal units was found to have a significant influence on the optical absorption properties, electronic energy levels, molecular ordering, charge carrier mobility and morphology of the resulting active layers. In the fourth study, side-chain modification of the phenothiazine unit of symmetrically configured small molecules with an oxygen-containing (methoxyethoxy ethyl) side chain resulted in the enhancement of the dielectric constant. Although absorption properties were unchanged in solution, a dense π-π stacking was observed in the solid state.

    In summary, it is demonstrated that phenothiazine is a promising candidate and worth exploring donor material for OSCs. Its versatility as a π-linker and as a central core unit in symmetric and asymmetric configurations has been explored. The use of nonplanar building blocks such as phenothiazine for the construction of donor materials is an interesting strategy for controlling molecular aggregation and difficult solution processability of small molecules if it is combined with a judiciously designed conjugate backbone.

  • 7.
    Revoju, Srikanth
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Biswas, Subhayan
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sharma, Ganesh D.
    Asymmetric triphenylamine–phenothiazine based small molecules with varying terminal acceptor for solution processed bulk-heterojunction organic solar cells2018In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084Article in journal (Refereed)
    Abstract [en]

    Three compounds consisting of the electron-donating triphenylamine-phenothiazine conjugate backbone and each of the electron-withdrawing groups 3-ethylrhodanine, malononitrile and 1,3-indandione have been synthesized and used as donors in blends with [6,6]-phenyl-C70-butyric acid methyl ester (PC71BM) for organic solar cell devices. After improvements of the active layer structure by a selected donor-to-acceptor weight ratio and a two-step solvent and thermal annealing, the organic solar cells showed power conversion efficiency (PCE) in the range of 4.29-7.25 %. The highest PCE was obtained for the bulk heterojunction device with the indandione compound, which can be attributed to its better absorption profile, higher crystallinity, more balanced electron and hole transport, higher charge collection efficiency and reduced recombination, in comparison with the photovoltaic cells from the other two compounds. DFT-calculated characteristics, absorption spectra and cyclic voltammetry of the compounds, along with x-ray diffraction patterns of blend films, are used to validate photovoltaic results. 

  • 8.
    Saleeb, Michael
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sundin, Charlotta
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Aglar, Öznur
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pinto, Ana Filipa
    Ebrahimi, Mahsa
    Forsberg, Åke
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Schüler, Herwig
    Elofsson, Mikael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Structure-activity relationships for inhibitors of Pseudomonas aeruginosa exoenzyme S ADP-ribosyltransferase activity2018In: European Journal of Medicinal Chemistry, ISSN 0223-5234, E-ISSN 1768-3254, Vol. 143, p. 568-576Article in journal (Refereed)
    Abstract [en]

    During infection, the Gram-negative opportunistic pathogen Pseudomonas aeruginosa employs its type III secretion system to translocate the toxin exoenzyme S (ExoS) into the eukaryotic host cell cytoplasm. ExoS is an essential in vivo virulence factor that enables P. aeruginosa to avoid phagocytosis and eventually kill the host cell. ExoS elicits its pathogenicity mainly via ADP-ribosyltransferase (ADPRT) activity. We recently identified a new class of ExoS ADPRT inhibitors with in vitro IC50 of around 20 μM in an enzymatic assay using a recombinant ExoS ADPRT domain. Herein, we report structure-activity relationships of this compound class by comparing a total of 51 compounds based on a thieno [2,3-d]pyrimidin-4(3H)-one and 4-oxo-3,4-dihydroquinazoline scaffolds. Improved inhibitors with in vitro IC50 values of 6 μM were identified. Importantly, we demonstrated that the most potent inhibitors block ADPRT activity of native full-length ExoS secreted by viable P. aeruginosa with an IC50 value of 1.3 μM in an enzymatic assay. This compound class holds promise as starting point for development of novel antibacterial agents.

  • 9.
    Urbán, Béla
    et al.
    University of Pannonia, Institute of Chemistry, Department of Organic Chemistry, Egyetem u, Hungary.
    Szabó, Péter
    University of Pannonia, Institute of Chemistry, Department of Analytical Chemistry, Egyetem u, Hungary.
    Srankó, Dávid
    Hungarian Academy of Sciences, Centre for Energy Research, Department of Surface Chemistry and Catalysis, Hungary.
    Sáfrán, György
    Hungarian Academy of Sciences, Research Institute for Technical Physics and Materials Science, Hungary.
    Kollár, László
    University of Pécs, Department of Inorganic Chemistry and MTA-PTE Research Group for Selective Chemical Syntheses, Hungary.
    Skoda-Földes, Rita
    University of Pannonia, Institute of Chemistry, Department of Organic Chemistry, Egyetem u, Hungary.
    Double carbonylation of iodoarenes in the presence of reusable palladium catalysts immobilised on supported phosphonium ionic liquid phases2018In: Molecular Catalysis, ISSN 2468-8231, Vol. 445, p. 195-205Article in journal (Refereed)
    Abstract [en]

    The first heterogeneous carbonylation reaction carried out with palladium catalysts immobilised on phosphonium ion modified silica supports is reported. The supported ionic liquid phases were characterised by solid state NMR and FT-IR measurements. The presence of the phosphonium ions on the surface made it possible to carry out double carbonylation in apolar toluene efficiently that resulted in reduced metal leaching. The introduction of dicationic moieties on the solid support has been proved to lead to a further increase in catalyst stability. The catalysts were proved to produce α-ketoamide products with excellent selectivity in the carbonylation of iodoarenes with aliphatic amines while monocarbonylation was the only reaction observed with aniline derivatives. The catalysts could be recycled and used in at least 10 subsequent runs under optimised conditions.

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