Change search
Refine search result
1 - 12 of 12
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 1.
    Bowden, Tim
    Stockholm University.
    Studies on glycosylation mechanisms and synthesis of structures related to inositolphosphoglycans2000Doctoral thesis, comprehensive summary (Other academic)
  • 2.
    Hansson, Jonas
    Stockholm University.
    Synthesis of phosphate-containing oligosaccharides corresponding to capsular antigen structures from Haemophilus influenzae2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes the synthesis of spacer-equipped di- and trimeric oligosaccharide structures corresponding to fragments of the capsular polysaccharides of Haemophilus influenzae types c and f. Both of these polysaccharides are of the teichoic acid type, built up by disaccharide repeating units linked via interglycosidic phosphodiester bonds. Introduction of the phosphodiester linkages was accomplished employing the glycosyl H-phosphonate method. The syntheses are designed in such a way as to allow the formation of even larger structures, as well as conjugation to a carrier protein. The first section of this thesis presents a general overview of the biological significance and structural features of anomeric phosphodiesters and synthetic approaches towards these structures, including a literature survey of research in this area during the past decade. In the second part, a new approach to the synthesis of anomeric phosphodiester linkages, utilizing non-anomeric glycosyl H-phosphonate acceptors and various galactosyl donors in glycosylation reactions, is described. Finally, synthesis of the capsular polysaccharide fragments of H. influenzae types c and f is discussed.

  • 3.
    Höög, Christer
    Stockholm University.
    Three-dimensional structure of oligosaccharides from molecular dynamics simulations2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focuses on the conformation and flexibility of oligosaccharides around the glycosidic linkage. The methods employed for the elucidation of the three-dimensional structures of biomolecules are briefly described. The main techniques used here are computer simulations and molecular dynamics simulations in aqueous solution in particular. The experimental data derived from these simulations have been compared with nuclear magnetic resonance measurements. The results obtained demonstrate the occurrence of more than one conformation, even though at the same time the high value of the generalised order parameter indicates rigidity. Of special interest are the folded conformers discovered at the same linkage in a vicinally substituted trisaccharide dissolved in water. Such, folded conformers have been detected in carbohydrates earlier, but never at the same linkage.

    The free energy simulation methods thermodynamic perturbation and thermodynamic integration are described briefly and have been used to calculate the anomeric ratio of the monosaccharides D-xylose in water and methyl D-xyloside in methanol. Solvent effect of the a/b ratios were found to be small. The solvent structures surrounding these four monosaccharides were investigated utilising radial and spatial distribution functions.

  • 4.
    Johansson, Karl-Jonas
    Stockholm University.
    Studies of the anomeric center: mechanism and synthesis2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is based on three publications and one appendix and is divided into two parts. The first part is a mechanistic study of the anomerization reaction of both aldo and keto glycosides and the second part is a synthetic study of a unusual type of glycosidic linker found in the lipopolysaccharide core Proteus Mirabilis 0270.

    The first chapter contains a general introduction to the thesis.The second chapter treats the anomerization reaction of alkyl furanosides both by trapping experiments and kinetics. The conclusion from these studies is that the reaction proceeds via a concerted endo-cyclic C-O bond cleavage.The third chapter concerns the anomerization of alkyl pyranosides by the same techniques as those used in chapter 2. The results from these studies confirm that the reaction proceeds via exo-cyclic C-O bond cleavage.In the fourth chapter the anomerization of methyl fructosides has been investigated by trapping experiments. The outcome of this study is that the anomerization of fructosides occur via exo-cyclic C-O bond cleavage and that the anomerization reaction proceeds faster than ring-interconverison.In the final chapter an analogue of the unusual type of glycosidic linker fond in Proteus Mirabilis 0270 has been synthesised i.e. methyl ((1S)-arabinosyl o-(1Æ4,6))-a-D-galactopyranoside.

  • 5.
    Jonasson, Catrin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium (II)-catalyzed oxidations of allenes and conjugated dienes2000Doctoral thesis, comprehensive summary (Other academic)
  • 6.
    Karlström, A. Sofia E.
    Stockholm University.
    Copper- and nickel-catalyzed cross-coupling reactions: synthesis of 2-substituted 1,3-dienes and mechanistic and synthetic studies of the copper-mediated allylic substitution reaction2000Doctoral thesis, comprehensive summary (Other academic)
  • 7.
    Lindström, Ulf
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis and [3,3]-Sigmatropic Rearrangement of Vinylaziridines2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [sv]

    A general synthetic route from vinylepoxides to vinylaziridines via 1,2-amino alcohols was developed. The 1,2-amino alcohols were obtained from a stereospecific and regioselective aminolysis of vinylepoxides. The synthetic scope of the aminolysis could be expanded by the use of a microwave-assisted protocol. Some of the 1,2-amino alcohols were dehydrated with PPh3/DEAD to afford N-H vinylaziridines. All of the so obtained N-H vinylaziridines were acylated to give the corresponding N-acyl vinylaziridines. When variously substituted N-acyl vinylaziridines were subjected to LiHMDS in THF, the resulting amide enolates underwent a stereoselective aza-[3,3]-Claisen rearrangement to give mono-, di- and trisubstituted seven-membered lactams. The scope and limitations of the rearrangement were investigated. Finally, the aminolysis of vinylepoxides was applied in an asymmetric synthesis of (+)-1-deoxynojirimycin.

  • 8.
    Mühlman, Anna
    Stockholm University.
    Synthesis of inhibitors against the human immunodeficiency virus: diol-based inhibitors of the HIV-1 protase and 4-substituted carbocyclic nucleoside analogues2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The pandemic spread of HIV infection and AIDS has resulted in intensive research designed to develop effective therapeutic agents. Development of inexpensive inhibitors is necessary to allow treatment of HIV infections in the Third World.

    In the present thesis, the design and synthesis of several inhibitors of the HIV-1 virus are described. The first section presents a general overview of the life-cycle of HIV, i.e., the replication cycle and the functions of the HIV reverse transcriptase and HIV protease, as well as the strategies underlying anti-HIV chemotherapy. The design of C2-symmetric inhibitors of the HIV-1 protease, incorporating C-terminal duplication is also outlined. On the basis of molecular modelling, L-mannaric acid was selected as a general scaffold, i.e., the chiral template from which carbohydrate-based inhibitors were developed. By varying the pattern of substitution on this L-mannaric acid template, structural analogues that retained high anti-HIV activity were designed.

    The second section of the thesis describes four different syntheses of the C2-symmetric inhibitors of the HIV-1 protease, two of which provide access to potent inhibitors in a relatively few steps. These procedures open the possibility of developing cost-effective drugs.

    Finally, construction and synthesis of two 4-substituted carbocyclic nucleoside analogues, targeted against the HIV reverse transcriptase, are described.

  • 9.
    Olofsson, Berit
    et al.
    Royal Institute of Technology, Sweden.
    Khamrai, Uttam
    Royal Institute of Technology, Sweden.
    Somfai, Peter
    Royal Institute of Technology, Sweden.
    A regio- and stereodivergent synthesis of vic-amino alcohols2000In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 2, no 25, p. 4087-4089Article in journal (Refereed)
    Abstract [en]

    A regio- and stereodivergent synthesis of vic-amino alcs., e.g., I, starting from vinylepoxides is described. The developed strategy focuses on the propensity of vinylepoxides II and vinylaziridines III (R = PhCH2O, PhCH2, 4-MeOC6H4CH2O, R1 = H, CH2OCH2C6H4OMe-4) to be ring-opened at the allylic position by suitable nucleophiles and makes use of reactions that perform such tasks selectively with either retention or inversion of configuration.

  • 10.
    Salakdeh, Esmail Yousefi
    Stockholm University.
    Synthesis of nucleotide, peptide and lipid containing molecular tools for life science studies2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is based on five parts. The first and second chapters describes two synthetic routes, employing different protecting group strategies for synthesis of uridine 3'-(ethyl, 2-ethoxyethyl, 2-chloroethyl, 2,2-dichloroethyl and 2,2,2-trichloroethyl) phosphate. In the first synthetic route, uridine was protected with acid labile protecting groups, 4-methoxytetrahydropyran-4-yl for the 2'-OH group and 4-methoxytriphenylmethyl for the 5'-OH group. In the second synthesis route the tert-butyldimethylsilyl (TBDMS) was used for protection of the 2'- and 5'- hydroxyls. Silyl deprotection was performed using triethylamine trihydrofluoride.

    In the third chapter a method for O- and S-palmitoylation of non-protected peptides is described. The procedure consists of treatment of the peptides with excess of palmitoyl chloride in neat trifluoroacetic acid for 10 minutes at room temperature. The tripeptides Gly-Cys-Phe and Gly-Ser-Phe were S- and O-palmitoylated and the hydrophobic Pulmonary Surfactant Protein-C model peptides were converted to the respective S,S- and O,O-dipalmitoylated peptides.

    The production of S-citronellyl-L-cysteine and S-dolicyl-L-cysteines for use as mass spectrometry standards is described in chapter four. For formation of the thioether linkage, a mesylated citronellol and/or mesylated dolichols and L-cysteine ethyl ester were employed.

    Finally, in the last chapter a route for synthesis of 8-aminoadenosine 5'-(aminoalkyl phosphates), analogues of aminoacyl adenylates is described. The 5'-H-phosphonate of 2', 3'-O, O-benzylidene-8-bromoadenosine, with unprotected base was condensed with benzyloxycarbonyl (Z) protected amino alcohols (L-isoleucinol, L-histidinol and L-methioninol), in the presence of bis(2-oxo-oxazoline-3-yl)phosphonic chloride. After oxidation the 8-bromo was transformed into the 8-azido moiety by sodium azide in dimethyl sulfoxide. Deprotection of the benzylidene and benzyloxycarbonyl (Z) groups as well as reduction of the azido to the desired amino function was accomplished in a single step by catalytic transfer hydrogenation (palladium-carbon or palladium black in 80% acetic acid).

  • 11.
    Staaf, Mikael
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Structural and conformational studies of bacterial polysaccharides employing NMR spectroscopy2000Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Methods and approaches for performing structural and conformational analysis of bacterial polysaccharides in solution are described. The structure of one exopolysaccharide from Lactobacillus helveticus and two O-antigens from Escherichia coli have been determined using NMR spectroscopy, chemical degradation and mass spectrometry. This thesis discusses different problems encountered in connection with these structural elucidations, namely, overlap of NMR signals, heterogeneity in the polysaccharide sequence and the configurations of a nonulosonic acid.

    A conformational analysis of the enterobacterial common antigen (ECA) in the form of a cyclic dodecamer is described. Nuclear Overhauser effects (NOEs) and heteronuclear three-bond coupling constants (3JCH) over the glycosidic linkages were determined and used to calculate proton-proton distances and torsion angles. Residual dipolar couplings were measured in a liquid crystalline medium. These couplings provide orientational information distinct from that contained in the local NOE and 3JCH data. The experimental data were compared to the averaged distances, three-bond proton-carbon coupling constants and C-H vector orientations in a model obtained by molecular dynamics simulations. From a fragment that were in agreement with experimental data, a three-dimensional structure was generated for the cyclic ECA in solution

  • 12.
    Turek, Dominika
    Stockholm University.
    Synthesis of complex carbohydrates corresponding to the Lewis b blood group antigen and Vibrio cholerae polysaccharide structures2000Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is divided into two parts. The first part describes the syntheses of the Lewis b blood group antigen hexasaccharide and parts thereof. The Leb blood group antigen is one of the binding epitopes for the Helicobacter pylori bacteria in the human stomach. The oligosaccharides containing N-acetyl glucosamine, galactose and fucose, were synthesised as their 8-methoxycarbonyloctyl or 2-azidoethyl spacer glycosides and were conjugated to proteins using activated esters or the diethyl squarate methodology for binding studies with H. pylori. In the second part, structures from the lipopolysaccharide and capsular polysaccharide of Vibrio cholerae O139 synonym Bengal and Vibrio cholerae O22 were synthesised as 2-(4-benzyloxyamidophenyl)ethyl spacer glycosides for the study of their immunological properties. Unusual features of these oligosaccharides are the presence of a 6-membered cyclic phosphate diester and the 2,6-dideoxysugar colitose.

    The glycosylation reactions included halide-assisted couplings of the bromosugars of fucose and colitose, AgOTf promotion of galactosyl bromides, and DMTST or NIS promotion of thioethyl glycosides.

1 - 12 of 12
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf