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  • 2601. Trillo, Paz
    et al.
    Slagbrand, Tove
    Tinnis, Fredrik
    Adolfsson, Hans
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden.
    Mild Reductive Functionalization of Amides into N-Sulfonylformamidines2017In: ChemistryOpen, ISSN 2191-1363, Vol. 6, no 4, p. 484-487Article in journal (Refereed)
    Abstract [en]

    The development of a protocol for the reductive functionalization of amides into N-sulfonylformamidines is reported. The one-pot procedure is based on a mild catalytic reduction of tertiary amides into the corresponding enamines by the use of Mo(CO)(6) (molybdenum hexacarbonyl) and TMDS (1,1,3,3-tetramethyldisiloxane). The formed enamines were allowed to react with sulfonyl azides to give the target compounds in moderate to good yields.

  • 2602.
    Trupina, Snjezana
    Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry . Linköping University, Department of Physics, Chemistry and Biology.
    Synthesis of Metalloporphyrins with Oligothiophenes as Probes for Amyloid Diseases2010Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Abnormal aggregation of misfolded proteins is related to numerous neurodegenerative diseases, which include Alzheimer’s, Parkinson’s disease and prion diseases. Luminescent conjugated probes (LCPs) have been used as dyes for these supramolecular assemblies termed amyloid fibrils. To these probes, metalloporphyrin (MP) derivates have been attached to achieve new spectroscopic properties, which will allow for new ways to study protein aggregation diseases.

    In this thesis the synthesis of two different LCPs anchored porphyrin derivates are described. The LCPs are synthesized from 3-thiopheneacetic acid and additional thiophene units are added with the use of Suzuki cross coupling reaction. The porphyrin is synthesized from pyrrol, benzaldehyde and methyl-4- formylbenzoate in a condensation reaction. In the first target molecule (TM) the porphyrin and thiophene are coupled with a spacer and the second one is a direct coupling between the two compounds.

  • 2603.
    Träff, Annika
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Asymmetric transformation of ß- and γ-functionalized alcohols: Study of combined ruthenium-catalyzed racemization and enzymatic resolution2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The major part of this thesis describes the asymmetric synthesis of β- and γ-amino alcohols through the combination of ruthenium catalyzed racemization and enzymatic kinetic resolution.

    The dynamic kinetic resolution, DKR, protocol for chlorohydrins was improved by employing Bäckvall’s catalyst, which is a base activated racemization catalyst, in combination with Burkholderia cepacia lipase. These optimized conditions broadened the substrate scope and improved the yields and ee’s of the obtained chlorohydrin acetates. The utility of the method was demonstrated in the synthesis of (S)-salbutamol.

    In the second part of the thesis, DKR was utilized in the enantio-determining step of the total synthesis of (R)-duloxetine. Optimized DKR conditions, combining Bäckvall’s catalyst together with Candida antarctica lipase B, afforded a β-cyano acetate in high yield and ee. (R)-Duloxetine was accessible through synthetic alterations of the enantioenriched β-cyano acetate in high overall yield.

    A dynamic kinetic asymmetric transformation, DYKAT, protocol to obtain enantio- and diastereomerically pure γ-amino alcohols was developed. In a first step N-Boc-aminoketones were obtained in high enantiomeric purity through a proline-catalyzed Mannich reaction. Subsequent in situ reduction coupled with a highly efficient DYKAT yielded γ-amino acetates in high dr and ee. The γ-amino alcohols were available through simple hydrolysis/deprotection with retained stereochemistry.

    In the final part of the thesis a heterogeneous bifunctional catalytic system is reported, which combines the catalytic properties of transition metal-catalyzed racemization with enzymatic acylation. A novel ruthenium-phosphonate complex was synthesized and then covalently anchored to the active site of solid supported Candida antarctica lipase B. The partially inhibited beads proved to be catalytically active both in racemization as well as enzymatic acylation.

  • 2604.
    Träff, Annika
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dynamic Kinetic Resolution. A Tool for Bringing Bioorganic and Organometallic Chemistry together.2009Licentiate thesis, comprehensive summary (Other academic)
  • 2605.
    Träff, Annika
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bogár, Krisztián
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Warner, Madeleine
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Highly efficient route for enantioselctive preparation of chlorohydrins via dynamic kinetic resolution2008In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 10, no 21, p. 4807-4810Article in journal (Refereed)
    Abstract [en]

    Dynamic kinetic resolution (DKR) of various aromatic chlorohydrins with the use of Pseudomonas cepacia lipase (PS-C “Amano” II) and ruthenium catalyst 1 afforded chlorohydrin acetates in high yields and high enantiomeric excesses. These optically pure chlorohydrin acetates are useful synthetic intermediates and can be transformed to a range of important chiral compounds.

  • 2606.
    Träff, Annika
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bogár, Krisztián
    Warner, Madeleine
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Highly efficient route for enantioselective preparation of chlorohydrins via dynamic kinetic resolution2009In: Abstracts of Papers, 238th American Chemical Society National Meeting, Washington, DC, United States, August 16-20, 2009, American Chemical Society , 2009Conference paper (Other academic)
  • 2607.
    Träff, Annika
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lihammar, Richard
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    A Chemoenzymatic Dynamic Kinetic Resolution Approach to Enantiomerically Pure (R)- and (S)-Duloxetine2011In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 76, no 10, p. 3917-3921Article in journal (Refereed)
    Abstract [en]

    The synthesis of (R)-duloxetine is described. Dynamic kinetic resolution of β-hydroxynitrile rac-1 using Candida antarctica lipase B (CALB, N435) and ruthenium catalyst 6 afforded β-cyano acetate (R)-2 in high yield and in excellent enantioselectivity (98% ee). The subsequent synthetic steps were straightforward and (R)-duloxetine was isolated in 37% overall yield over 6 steps. The synthetic route also constitute a formal total synthesis of (S)-duloxetine.

  • 2608.
    Träff, Annika
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Solarte, Carmen E.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Chemoenzymatic dynamic kinetic resolution as a key step in the enantioselective synthesis of (S)-salbutamol2011In: Collection of Czechoslovak Chemical Communications, ISSN 0010-0765, E-ISSN 1212-6950, Vol. 76, no 7, p. 919-927Article in journal (Refereed)
    Abstract [en]

    The synthesis of (S)-salbutamol is described.  By utilizing DKR in the enantiodetermining step, employing Burkholderia cepacia lipase (PS-IM), (S)-acetate ((S)-6) was obtained in excellent enantiomeric excess (98%).  The subsequent transformations yielded the salt of (S)-salbutamol with retained stereochem.

  • 2609.
    Tsakoumis, Nikolaos E.
    et al.
    Norwegian Univ Sci & Technol NTNU, Dept Chem Engn, NO-7491 Trondheim, Norway..
    Patanou, Eleni
    Norwegian Univ Sci & Technol NTNU, Dept Chem Engn, NO-7491 Trondheim, Norway..
    Lögdberg, Sara
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Johnsen, Rune E.
    Tech Univ Denmark, Dept Energy Convers & Storage, DK-4000 Roskilde, Denmark..
    Myrstad, Rune
    SINTEF Mat & Chem, NO-7465 Trondheim, Norway..
    van Beek, Wouter
    ESRF, Swiss Norwegian Beamlines SNBL, F-38043 Grenoble, France..
    Rytter, Erling
    Norwegian Univ Sci & Technol NTNU, Dept Chem Engn, NO-7491 Trondheim, Norway.;SINTEF Mat & Chem, NO-7465 Trondheim, Norway..
    Blekkan, Edd A.
    Norwegian Univ Sci & Technol NTNU, Dept Chem Engn, NO-7491 Trondheim, Norway..
    Structure-Performance Relationships on Co-Based Fischer-Tropsch Synthesis Catalysts: The More Defect-Free, the Better2019In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 9, no 1, p. 511-520Article in journal (Refereed)
    Abstract [en]

    Understanding and utilizing structure-performance relationships in catalytic nanomaterials is the epitome of catalysis science. Knowledge at the atomic level can potentially allow rational design of more selective and energy-efficient catalytic materials. Fischer-Tropsch synthesis on cobalt is an example of a complicated system that operates in a narrow process regime, and the nature of the reaction product is governed by numerous parameters. On an industrial model catalyst, we have simplified the structure of the active, metallic nanoparticles into a predominantly hexagonal close-packed structure via the use of a Co2C precursor. By varying the final reduction temperature, we could mildly modify catalyst microstructural properties at the nanoparticle (NP) level. Catalytic materials, although with minimal structural differences, showed significantly different performance. Evidently there is a narrow window for complete utilization of the hexagonal close-packed Co crystallites that lies between removal of lattice carbon, that remains from the Co2C precursor, and the initiation of stacking disorder, because of a transition to the face-centered cubic Co structure. Fischer-Tropsch synthesis performance indicators show that Co NPs with minimum number of crystal defects outperform catalysts with lattice defects, because of the existence of either lattice carbon or stacking faults. Therefore, catalyst preparation and activation procedures probably should be designed targeting defect-free Co crystallites.

  • 2610.
    Tsupova, Svetlana
    et al.
    Heidelberg Univ, Organ Chem Inst, Neuenheimer Feld 270, D-69120 Heidelberg, Germany..
    Cadu, Alban
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry. Heidelberg Univ, Organ Chem Inst, Neuenheimer Feld 270, D-69120 Heidelberg, Germany..
    Stuck, Fabian
    Heidelberg Univ, Organ Chem Inst, Neuenheimer Feld 270, D-69120 Heidelberg, Germany..
    Rominger, Frank
    Heidelberg Univ, Organ Chem Inst, Neuenheimer Feld 270, D-69120 Heidelberg, Germany..
    Rudolph, Matthias
    Heidelberg Univ, Organ Chem Inst, Neuenheimer Feld 270, D-69120 Heidelberg, Germany..
    Samec, Joseph S. M.
    Stockholm Univ, Dept Organ Chem, S-10691 Stockholm, Sweden..
    Hashmi, A. Stephen K.
    Heidelberg Univ, Organ Chem Inst, Neuenheimer Feld 270, D-69120 Heidelberg, Germany.;King Abdulaziz Univ, Fac Sci, Dept Chem, Jeddah 21589, Saudi Arabia..
    Dual Gold(I)-catalyzed Cyclization of Dialkynyl Pyridinium Salts2017In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 9, no 11, p. 1915-1920Article in journal (Refereed)
    Abstract [en]

    Novel dialkynyl pyridines were synthesized and protected as alkyl salts for dual gold(I)-catalyzed cycloisomerization. Different alkyl groups and counter ions were screened for the salts, with benzyl and hexafluorophosphate providing the best results. The cyclization led to NMR yields of >95% being obtained for a number of substrates. Step-wise hydrogenation of products could be performed in one-pot by Pd/C, with selective reduction of the double bonds, followed by deprotection of the benzyl group.

  • 2611.
    Tundup, Smanla
    et al.
    Univ Georgia, Dept Infect Dis, Coll Vet Med, Athens, GA 30602 USA.;Univ Chicago, Dept Microbiol, Chicago, IL 60637 USA..
    Srivastava, Leena
    Univ Georgia, Dept Infect Dis, Coll Vet Med, Athens, GA 30602 USA..
    Norberg, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Watford, Wendy
    Univ Georgia, Dept Infect Dis, Coll Vet Med, Athens, GA 30602 USA..
    Harn, Donald
    Univ Georgia, Dept Infect Dis, Coll Vet Med, Athens, GA 30602 USA.;Univ Georgia, Ctr Trop & Emerging Global Dis, Athens, GA 30602 USA..
    A Neoglycoconjugate Containing the Human Milk Sugar LNFPIII Drives Anti-Inflammatory Activation of Antigen Presenting Cells in a CD14 Dependent Pathway2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 9, article id e0137495Article in journal (Refereed)
    Abstract [en]

    The milk pentasaccharide LNFPIII has therapeutic action for metabolic and autoimmune diseases and prolongs transplant survival in mice when presented as a neoglycoconjugate. Within LNFPIII is the Lewis(x) trisaccharide, expressed by many helminth parasites. In humans, LNFPIII is found in human milk and also known as stage-specific embryonic antigen-1. LNFPIII-NGC drives alternative activation of macrophages and dendritic cells via NF kappa B activation in a TLR4 dependent mechanism. However, the connection between LNFPIII-NGC activation of APCs, TLR4 signaling and subsequent MAP kinase signaling leading to anti-inflammatory activation of APCs remains unknown. In this study we determined that the innate receptor CD14 was essential for LNFPIII-NGC induction of both ERK and NFkB activation in APCs. Induction of ERK activation by LNFPIII-NGC was completely dependent on CD14/TLR4-Ras-Raf1/TPL2-MEK axis in bone marrow derived dendritic cells (BMDCs). In addition, LNFPIII-NGC preferentially induced the production of Th2 "favoring" chemokines CCL22 and matrix metalloprotease protein-9 in a CD14 dependent manner in BMDCs. In contrast, LNFPIII-NGC induces significantly lower levels of Th1 "favoring" chemokines, MIP1 alpha, MIP1 beta and MIP-2 compared to levels in LPS stimulated cells. Interestingly, NGC of the identical human milk sugar LNnT, minus the alpha 1-3 linked fucose, failed to activate APCs via TLR4/MD2/CD14 receptor complex, suggesting that the alpha 1-3 linked fucose in LNFPIII and not on LNnT, is required for this process. Using specific chemical inhibitors of the MAPK pathway, we found that LNFPIII-NGC induction of CCL22, MMP9 and IL-10 production was dependent on ERK activation. Over all, this study suggests that LNFPIII-NGC utilizes CD14/TLR4-MAPK (ERK) axis in modulating APC activation to produce anti-inflammatory chemokines and cytokines in a manner distinct from that seen for the pro-inflammatory PAMP LPS. These pathways may explain the in vivo therapeutic effect of LNFPIII-NGC treatment for inflammation based diseases.

  • 2612.
    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.

  • 2613.
    Tuzina, Pavel
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Development of New Methodology in Organic Synthesis: Lewis Acid-Mediated Rearrangements of Ammonium Ylides and Addition of 1, 3-bis(silyl) propenes to Aldehydes2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with the development of new methodologies in organicsynthesis. The main focus is on the development of Lewis acid-mediated [1,2]-rearrangements of ammonium ylides and the novel addition of 1,3-bis(silyl)propenes to carbonyl compounds.The first part of this thesis describes the development of a Lewis acidmediated[1,2]-Stevens rearrangement of various glycine derivatives. Thismethodology was then applied to the development of an asymmetric Lewis acid mediated [1,2]-Stevens rearrangement of cyclic ammonium ylides. There markably high degree of C→N→C chirality transfer is described. In addition, this methodology was successfully applied to the synthesis of various quaternary proline derivatives in enantiomerically pure form.Secondly, a brief study of the asymmetric [2,3]-rearrangement of α-substitutedglycine derivatives is presented. The investigation revealed a severely limitedreaction scope. The subsequent study on developing super-reactive cationicLewis acid also met with little success.Finally, an addition reaction of various 1,3-bis(silyl)propenes to glyoxalates has been developed. The reaction products correspond to the direct vinylation ofglyoxalates. The corresponding highly functionalized δ-hydroxy allylsilanes were obtained in high yields.

  • 2614.
    Tuzina, Pavel
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Somfai, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Asymmetric Lewis Acid Mediated 1,2 -Rearrangement of Proline-Derived Ammonium Ylides2009In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 11, no 4, p. 919-921Article in journal (Refereed)
    Abstract [en]

    The first example of asymmetric Lewis acid mediated [1,2]-rearrangement of N-benzylic proline amides to form quaternary proline derivatives is reported. The presented reaction is shown to proceed with remarkable high C-N-C chirality transfer. Various quaternary proline derivatives have been prepared in good to excellent yields and high enantiomeric purity.

  • 2615.
    Tuzina, Pavel
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Somfai, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lewis acid mediated 1,2 -rearrangement of ammonium ylides2007In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 48, no 28, p. 4947-4949Article in journal (Refereed)
    Abstract [en]

    The first example of Lewis acid mediated [1,2]-rearrangement of various glycine derivatives has been developed. A brief study of steric and electronic properties of the migrating group is presented. The corresponding amides were obtained in good yields and in the case of substrate 4d, moderate diastereoselectivity was observed.

  • 2616.
    Tuzina, Pavel
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Somfai, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lewis acid-promoted carbonyl addition of 1,3-bis(silyl)propenes2008In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, no 48, p. 6882-6884Article in journal (Refereed)
    Abstract [en]

    A novel synthetic protocol for Lewis acid-promoted addition of 1,3-bis(silyl)propenes to N-phenyl glyoxylamide and ethyl glyoxylate is developed. The reaction does not appear to be influenced by the steric bulk of the 1,3-bis(silyl)propenes, and represents a new approach to vinylation of glyoxylates; the products are obtained in good yields.

  • 2617.
    Tyagi, Mohit
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Poongavanam, Vasanthanathan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Lindhagen, Marika
    AstraZeneca, Early Prod Dev, IMED Biotech Unit, Pharmaceut Sci, Gothenburg, Sweden.
    Pettersen, Anna
    AstraZeneca, Early Prod Dev, IMED Biotech Unit, Pharmaceut Sci, Gothenburg, Sweden.
    Sjö, Peter
    DNDi, 15 Chemin Louis Dunant, CH-1202 Geneva, Switzerland.
    Schiesser, Stefan
    AstraZeneca, Med Chem Resp Inflammat & Autoimmun, IMED Biotech Unit, Gothenburg, Sweden.
    Kihlberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Toward the Design of Molecular Chameleons: Flexible Shielding of an Amide Bond Enhances Macrocycle Cell Permeability2018In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 20, no 18, p. 5737-5742Article in journal (Refereed)
    Abstract [en]

    A series of macrocycles inspired by natural products were synthesized to investigate how side-chains may shield amide bonds and influence cell permeability. NMR spectroscopy and X-ray crystallography revealed that the phenyl group of phenylalanine, but not the side-chains of homologous or aliphatic amino acids, shields the adjacent amide bond through an intramolecular NH-pi interaction. This resulted in increased cell permeability, suggesting that NH-pi interactions may be used in the design of molecular chameleons.

  • 2618.
    Tšupova, Svetlana
    et al.
    Ruprecht-Karls-Universität Heidelberg.
    Cadu, Alban
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
    Stuck, Fabian
    Ruprecht-Karls-Universität Heidelberg.
    Rominger, Frank
    Ruprecht-Karls-Universität Heidelberg.
    Rudolph, Matthias
    Ruprecht-Karls-Universität Heidelberg.
    Samec, Joseph
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry. Stockholm University.
    Hashmi, A. Stephen K.
    Ruprecht-Karls-Universität Heidelberg.
    Dual Gold (I) Catalysed Cyclisation of Dialkynyl Pyridinium saltsManuscript (preprint) (Other academic)
    Abstract [en]

    Novel dialkynyl pyridines were synthesised and protected as alkyl salts for dual gold (I) catalysed cycloisomerisation. Different alkyl groups and counter ions were screened for the salts, with benzyl and PF6- providing the best results. The cyclisation led to NMR yields of >95% being obtained for a number of substrates. Step-wise hydrogenation of products could be carried out in one-pot by Pd/C, with selective reduction of the double bonds, followed by deprotection of the Bn group.

  • 2619.
    Ullah, Farman
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zhao, Gui-Ling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Deiana, Luca
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zhu, Mingzhao
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dziedzic, Pawel
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ibrahem, Ismail
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hammar, Peter
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Department of Structural Chemistry. Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Córdova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Enantioselective organocatalytic conjugate addition of fluorocarbon nucleophiles to α,β-unsaturated aldehydes2009In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 15, no 39, p. 10013-10017Article in journal (Refereed)
    Abstract [en]

    A highly chemo- and enantioselective organocatalytic addition of fluorocarbon nucleophiles, such as 1-fluoro-bis(phenylsulfonyl)methane, toα,β-unsaturated aldehydes is presented (see scheme). The reactions are catalyzed by simple chiral amines and give access to optically active fluorine derivatives in good yields and up to 95 % ee. Notably, the methodology can be applied to the formation of a chiral quaternary carbon center bearing a fluorine atom with high enantioselectivity.

  • 2620. Umlauf, G.
    et al.
    Bouwman, H.
    Cardenas, B.
    Fiedler, Heidelore
    United Nations Environment Programme (UNEP) Chemicals Branch, Châtelaine GE, Switzerland.
    Mariani, G.
    Mirikau, C.
    Skejo, H.
    Thanner, G.
    PCDD/F, PCB and HCB in soil and ash from brick production sites in Kenya, South Africa and Mexico2011In: Organohalogen Compounds, ISSN 1026-4892, Vol. 73, p. 1041-1045Article in journal (Refereed)
  • 2621.
    Unelius, C. Rikard
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Bohman, Björn
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Lorenzo, Marcelo
    Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas. Centro de Pesquisas René Rachou/FIOCRUZ, Belo Horizonte, BRAZIL.
    Tröger, A
    Univ of Hamburg.
    Franke, S
    Univ of Hamburg.
    Francke, Wittko
    Univ of Hamburg.
    (4S,5S)-2,2,4-Triethyl-5-methyl-1,3-dioxolane: A New Volatile Released by a Triatomine Bug2010In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 12, no 24, p. 5601-5603Article in journal (Refereed)
    Abstract [en]

    Adults of the triatomine bug, Triatoma brasiliensis release 2,2,4-triethyl-5-methyl-1,3-dioxolane (1) as a mixture of the (4S,5S)- and (4R,5R)-enantiomers in a ratio of 4:1. Among the volatile acetals identified from insects so far, this is the first example resulting from an intermolecular condensation of a carbonyl moiety and a diol substructure.

  • 2622.
    Unelius, C. Rikard
    et al.
    The Horticulture & Food Research Institute of New Zealand Limited (HortResearch), P.O. Box 51 Lincoln, New Zealand.
    Townsend, R J
    Mundy, D C
    Manning, L M
    Jackson, T A
    Suckling, D M
    Trap Comparisons and Lures for Monitoring Grass Grub, Costelytra zealandica2008In: New Zealand Plant Protection, ISSN 1175-9003, Vol. 61, p. 215-221Article in journal (Refereed)
  • 2623.
    Unelius, Rikard
    Organic Chemistry, KTH.
    Pheromone Synthesis: Conjugated Diene Systems and Oxygenated Carene Derivatives1989Doctoral thesis, comprehensive summary (Other academic)
  • 2624. Urbina, Felipe
    et al.
    Nordmark, Eva-Lisa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yang, Zhennai
    Weintraub, Andrej
    Scheutz, Flemming
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Structural elucidation of the O-antigenic polysaccharide from the enteroaggregative Escherichia coli strain 180/C3 and its immunochemical relationship with Escherichia coli O5 and O652005In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 340, no 4, p. 645-650Article in journal (Refereed)
    Abstract [en]

    The structure of the O-antigen polysaccharide (PS) from the enteroaggregative Escherichia coli strain 180/C3 has been determined. Sugar and methylation analysis together with 1H and 13C NMR spectroscopy were the main methods used. The PS is composed of tetrasaccharide repeating units with the following structure:→2)-β-d-Quip3NAc-(1→3)-β-d-Ribf-(1→4)-β-d-Galp-(1→3)-α-d-GalpNAc-(1→Analysis of NMR data indicates that the presented sequence of sugar residues also represents the biological repeating unit of the O-chain. The structure is closely related to that of O-antigen polysaccharide from E. coli O5 and partially to that of E. coli O65. The difference between the O-antigen from the 180/C3 strain and that of E. coli O5 is the linkage to the d-Quip3NAc residue, which in the latter strain is 4-O-substituted. The E. coli O65 O-antigen contains as part of its linear pentasaccharide repeating unit a similar structural element, namely →4)-β-d-GalpA-(1→3)-α-d-GlcpNAc-(1→2)-β-d-Quip3NAc-(1→, thereby indicating that a common epitope could be present for the two polysaccharides. Monospecific anti-E. coli O5 rabbit serum did not distinguish between the two positional isomeric structures neither in slide agglutination nor in an indirect enzyme immunoassay. The anti-O65 serum did react with both the 180/C3 and O5 LPS showing a partial cross-reactivity.

  • 2625.
    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.

  • 2626.
    Utas, Josefin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hydrogen Bonded Phenols as Models for Redox-Active Tyrosines in Enzymes2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with the impact of hydrogen bonding on the properties of phenols. The possibility for tyrosine to form hydrogen bonds to other amino acids has been found to be important for its function as an electron transfer mediator in a number of important redox enzymes. This study has focused on modeling the function of tyrosine in Photosystem II, a crucial enzyme in the photosynthetic pathway of green plants.

    Hydrogen bonds between phenol and amines in both inter- and intramolecular systems have been studied with quantum chemical calculations and also in some solid-state structures involving phenol and imidazole.

    Different phenols linked to amines have been synthesized and their possibilities of forming intra- and intermolecular hydrogen bonds have been studied as well as the thermodynamics and kinetics of the generation of phenoxyl radicals via oxidation reactions.

    Since carboxylates may in principle act as hydrogen bond acceptors in a manner similar to imidazole, proton coupled electron transfer has also been studied for a few phenols intramolecularly hydrogen bonded to carboxylates with the aim to elucidate the mechanism for oxidation. Electron transfer in a new linked phenol—ruthenium(II)trisbipyridine complex was studied as well.

    The knowledge is important for the ultimate goal of the project, which is to transform solar energy into a fuel by an artificial mimic of the natural photosynthetic apparatus

  • 2627.
    Utas, Josefin E.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olofsson, Berit
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Efficient Synthesis of 2-Substituted Imidazoles by Palladium-Catalyzed Cross-Coupling with Benzylzinc Reagents2006In: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, no 12, p. 1965-1967Article in journal (Refereed)
    Abstract [en]

    Substituted benzylzinc reagents have been used in novel cross-coupling reactions with 2-iodo imidazoles to form compounds containing both a phenol and an imidazole moiety. The ­intramolecular hydrogen-bonding properties of these compounds were subsequently studied.

  • 2628.
    Utas, Josefin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kritikos, Mikael
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Sandström, Dick
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Water as a Hydrogen Bonding Bridge between a Phenol and Imida-zole. A Simple Model for Water Binding in Enzymes2006In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1757, no 12, p. 1592-1596Article in journal (Refereed)
    Abstract [en]

    The X-ray crystal structure of the mono-hydrate of 2,2-bis(imidazol-1-ylmethyl)-4-methylphenol has been determined. Three hydrogen bonds hold water very tightly in the crystal, as determined by deuterium solid-state NMR. The hydrogen bond between the phenolic hydroxyl and water appears to have about the same strength as the direct hydrogen bond to imidazole, suggesting that the structure can be a good model for hydrogen bonds that are mediated by a water molecule in enzymes.

  • 2629. Vallin, K S A
    et al.
    Emilsson, P
    Larhed, M
    Hallberg, A
    High-speed Heck reactions in ionic liquid with controlled microwave heating2002In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 67, no 17, p. 6243-6246Article in journal (Refereed)
    Abstract [en]

    Palladium-catalyzed Heck arylations in the polar and robust ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF(6)), have for the first time been accomplished under microwave irradiation. The couplings were efficiently performed in sealed tubes within 5-45 min of heating. Without significant reductions in yield, a phosphine-free ionic catalyst phase could be recycled in five successive 20 min reactions at 180 degreesC. The product was easily removed from the reaction medium by distillation.

  • 2630. Vallin, K S A
    et al.
    Larhed, M
    Hallberg, A
    Aqueous DMF-potassium carbonate as a substitute for thallium and silver additives in the palladium-catalyzed conversion of aryl bromides to acetyl arenes2001In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 66, no 12, p. 4340-4343Article in journal (Refereed)
    Abstract [en]

    Highly selective palladium-catalyzed internal alpha -arylations of alkyl vinyl ethers with aryl and heteroaryl bromides were conveniently conducted in aqueous DMF with potassium carbonate as base and with DPPP as bidentate ligand. The corresponding acetyl arene products were, after hydrolysis, isolated in good to excellent yields. This Heck reaction procedure does not require toxic thallium or expensive silver salt additives, is promoted by water, and is suggested to proceed via charged organopalladium intermediates. Single-mode microwave irradiation was utilized in one example to shorten the reaction time.

  • 2631. Vallin, K S A
    et al.
    Larhed, M
    Johansson, K
    Hallberg, A
    Highly selective palladium-catalyzed synthesis of protected alpha,beta-unsaturated methyl ketones and 2-alkoxy-1,3-butadienes. High-speed chemistry by microwave flash heating2000In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 65, no 15, p. 4537-4542Article in journal (Refereed)
    Abstract [en]

    A selective and mild procedure is described for the direct synthesis of 2-alkene-2-methyl-1,3-dioxolanes via regiocontrolled Heck vinylation of commercially available 2-hydroxyethyl vinyl ether. The procedure permits chemoselective transformation of a vinylic triflate or bromide into a blocked alpha,beta-unsaturated methyl ketone. Furthermore, a significantly improved and highly regioselective synthesis of 2-alkoxy-1,3-butadienes has been developed. Flash heating by microwave irradiation promotes the palladium-catalyzed reactions, and the starting materials are fully converted after reaction times of 5-7 min.

  • 2632. Vallin, K S A
    et al.
    Zhang, Q S
    Larhed, M
    Curran, D P
    Hallberg, A
    A new regioselective Heck vinylation with enamides. Synthesis and investigation of fluorous-tagged bidentate ligands for fast separation2003In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 68, no 17, p. 6639-6645Article in journal (Refereed)
    Abstract [en]

    Internal ligand-controlled Heck vinylations of enamides were performed with high regioselectivity and delivered moderate to good yields of dienamides. Controlled heating by microwave irradiation accelerated the palladium-catalyzed reactions, and full conversions were achieved after reaction times of only 15-30 min. New bidentate fluorous-tagged 1,3-bis(diphenylphosphino)propane ligands (F-dppp's) were synthesized and examined. The cationic vinylations of the enamides with F-dppp ligands rendered essentially the same alpha-selectivity and catalytic activity as in those vinylations where nonfluorous ligands were employed. After reaction, the fluorous-tagged ligand material was easily removed by convenient solid fluorous phase separation. The high selectivity, simplicity, and generality of the experimental procedure should make this approach to 2-acylamino-1,3-butadienes attractive.

  • 2633.
    van Bavel, Bert
    et al.
    Örebro University, School of Science and Technology.
    van der Veen, I.
    Nilsson, H.
    de Boer, J.
    Fiedler, Heidelore
    United Nations Environment Programme DTIE Chemicals Branch, Châtelaine GE, Switzerland.
    Results from UNEPs 2nd Global Interlaboratory Assessment: Dioxinlike POPs2014In: Organohalogen Compounds, ISSN 1026-4892, Vol. 76, p. 1632-1635Article in journal (Refereed)
  • 2634. van der Veen, I.
    et al.
    Nilsson, H.
    van Bavel, Bert
    Örebro University, School of Science and Technology.
    de Boer, J.
    Fiedler, Heidelore
    United Nations Environment Programme (UNEP) Chemicals, Châtelaine GE, Switzerland.
    Results of UNEP’s 2nd Global Interlaboratory Assessment of the Persistent Organic Pollutants under the Stockholm Convention in Various Matrices2013In: Organohalogen Compounds, ISSN 1026-4892, Vol. 75, p. 387-390Article in journal (Refereed)
  • 2635.
    van der Veen, Ike
    et al.
    Vrije Universiteit, Dept. Environment & Health, Amsterdam, The Netherlands.
    Fiedler, Heidelore
    Örebro University, School of Science and Technology.
    de Boer, Jacob
    Vrije Universiteit, Dept. Environment & Health, Amsterdam, The Netherlands.
    Bi-ennial Global Interlaboratory Assessment on Persistent Organic Pollutants – Third Round 2016/2017, Organochlorine Pesticides, PCBs and Brominated Flame Retardants2017In: Organohalogen Compounds, Vol. 79, p. 575-578Article in journal (Refereed)
  • 2636.
    van der Werf, Angela
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Transformations of Nitrosoarenes and Alkynyl Enones: Selective Synthesis of Nitrogen-Containing Compounds2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The nitrogen atom plays a unique role in organic chemistry. It is abundantly found in organic materials and is responsible for the activity of many biologically relevant compounds. In this thesis, nitrosoarenes and keto- and pyridyl-substituted enynes are used as convenient starting materials for the selective synthesis of nitrogen-containing compounds.

    Nitrosoarenes are versatile compounds that can undergo a broad range of reactions. The nature of the nitroso group is significantly different from that of related nitrogen-based functional groups and this can be used as an advantage in the development of new methodology. In the first part of this thesis, the para-selective halogenation of nitrosoarenes with copper(II) halides as halogenating reagents is explored. The one-pot transformation of the products to the corresponding nitroarenes and anilines is demonstrated. The use of nitrosoarenes for radical N-perfluoroalkylation is presented in the next chapters. N-Perfluoroalkylation is a relatively new field and only a limited number of reagents and substrates have been employed so far. In this thesis, the stable and convenient Langlois reagent was used to achieve selective N-trifluoromethylation of nitrosoarenes to obtain the corresponding hydroxylamines. Longer perfluoroalkyl chains were investigated as well, but the less stable products were defluorinated to form hydroxamic acid derivatives. These products could be reduced to yield perfluoroalkyl amides.

    Keto- and pyridyl-substituted enynes are starting materials designed to undergo cyclization reactions in the presence of a metal catalyst and a nucleophile. This offers the possibility to obtain a variety of more complex molecular structures in a single step. In the second half of the thesis, the reaction between these starting materials and enamines is explored. A range of cyclopenta[c]furans were synthesized in good yields and with high diastereoselectivities from alkynyl enones and enamines with InBr3 as the catalyst. The enamines were formed in situ in a multicomponent reaction. Pyridyl-substituted enynes are the pyridine analogues of alkynyl enones and were found to form polycyclic indolizines in the reaction with cyclic enamines with AgOTf as a catalyst. Good yields and high to excellent diastereoselectivities were obtained. When the reaction was performed with in situ-generated enamines, different indolizine derivatives were obtained.

  • 2637.
    van der Werf, Angela
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hribersek, Matic
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selander, Nicklas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    N-Trifluoromethylation of Nitrosoarenes with Sodium Triflinate2017In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 19, no 9, p. 2374-2377Article in journal (Refereed)
    Abstract [en]

    A highly efficient N-trifluoromethylation of nitro-soarenes is reported. The inexpensive and convenient Langlois reagent (sodium triflinate) is employed as a Ch(3)-radical source in combination with a copper catalyst and an oxidant. N-Trifluoromethylated hychoxylamines are obtained in high yields within 1 h at room temperature. The addition of hydroquinone was found to be instrumental to prevent the formation of side products. The method is high-yielding is scalable, and displays a high functional group tolerance.

  • 2638.
    van der Werf, Angela
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selander, Nicklas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Para-Selective Halogenation of Nitrosoarenes with Copper(II) Halides2015In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 17, no 24, p. 6210-6213Article in journal (Refereed)
    Abstract [en]

    The para-selective direct bromination and chlorination of nitrosoarenes with copper(II) bromide and chloride is reported. Under mild reaction conditions, a rang of halogenated arylnitroso compounds are obtained in moderate to good yields with high regioselectivity. Additionally, the versatility of the method is demonstrated by the development of a One-pot procedure to obtain the corresponding para-halogenated aniline- and nitrobenzene derivatives.

  • 2639.
    van der Werf, Angela
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zheng, Zhiyao
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Selander, Nicklas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    N-Perfluoroalkylation of Nitrosoarenes with PerfluoroalkanesulfinatesManuscript (preprint) (Other academic)
  • 2640. Varedian, M.
    et al.
    Erdélyi, Máté
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Organic Chemistry.
    Karlén, A.
    Gogoll, Adolf
    A photoswitchable peptide mimetic2006Conference paper (Refereed)
  • 2641.
    Varedian, Miranda
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Photoswitchable Peptidomimetics: Synthesis and Photomodulation of Functional Peptides2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The secondary structure of peptides is of pivotal importance for their biological function. The introduction of photoswitchable moieties into the backbones of peptides provides a unique way of regulating their conformation using an external stimulus, i.e., light. This thesis addresses the design, synthesis, and conformational analysis of photoswitchable peptidomimetics (PSPM). Examples of photomodulation of their functional properties are given.

    PSPM were prepared by incorporation of stilbene and thioaurone chromophores (switches) into dipeptides. Synthetic schemes for preparing these chromophores have been developed. Their suitability for incorporation into peptidomimetics has been demonstrated, and the resulting PSPM have been subjected to photoisomerization as well as computational and spectroscopic conformational analysis. The chromophore’s potential as a β-hairpin inducer was particularly interesting.

    To investigate the factors that govern the formation of β-hairpins, a series of decapeptides were prepared. Turn regions consisting of amino acids or chromophores were combined with antiparallel peptide strands with hydrophobic side chains. Linear tryptophan zipper peptidomimetics and cyclic peptidomimetics with a second, hairpin-inducing turn region were particularly promising. Comparison between switches revealed that the more flexible stilbene is a better choice for upholding the β-hairpin conformation than the thioaurone.

    The catalytic properties of an artificial hydrolase with a helix-loop-helix structure can be improved by introducing a stilbene photoswitch into the loop region. Photoisomerization regulates the catalytic activity of this peptidomimetic, and provides a means to control its aggregation state.

    The activity of the enzyme Mycobacterium tuberculosis ribonucleotide reductase was realized by incorporating a stilbene moiety into a linear peptide. Here, one photoisomer proved to be an inhibitor at nM concentrations. A significantly lower effect was observed for the other isomer.

    Finally, the decomposition of thioaurones, mainly to thioflavonols and thiaindenes, under conditions used for solid-phase peptide synthesis has been mapped. These findings are expected to have implications for future use of this chromophore.

  • 2642.
    Varedian, Miranda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Erdélyi, Máté
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Persson, Åsa
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Interplaying factors for the formation of photoswitchable β-hairpins: The advantage of a flexible switch2009In: Journal of Peptide Science, ISSN 1075-2617, E-ISSN 1099-1387, Vol. 15, no 2, p. 107-113Article in journal (Refereed)
    Abstract [en]

    A series of peptidomimetics intended to promote the β-hairpin motif have been studied. Structural variations include a turn region with and without a photoswitchable chromophore, and strands with amino acid side chains supporting various degrees of interstrand interactions for hairpin stabilisation. The propensity of the compounds to form β-hairpinswas evaluated experimentally by NMR spectroscopy, translational self-diffusion studies and CD spectroscopy. In the presence of hairpin stabilising interstrand interactions, the structurally flexible stilbene chromophore appeared to be well compatible with the imposed secondary structure.

  • 2643.
    Varghese, Oommen P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Bioorganic Chemistry.
    Barman, Jharna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Bioorganic Chemistry.
    Pathmasiri, Wimal
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Bioorganic Chemistry.
    Plashkevych, Oleksandr
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Bioorganic Chemistry.
    Honcharenko, Dmytro
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Bioorganic Chemistry.
    Chattopadhyaya, Jyoti
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Bioorganic Chemistry.
    Conformationally constrained 2'-N,4'-C-ethylene-bridged thymidine (aza-ENA-T): synthesis, structure, physical, and biochemical studies of aza-ENA-T-modified oligonucleotides2006In: J. Am. Chem. Soc., Vol. 128, no 47, p. 15173-15187Article in journal (Refereed)
  • 2644.
    Vasil'ev A.A, Vielhauer O, Engman L, Pietzsch M, Serebryakov E.P
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Enzymatic Dissymmetriszation of Meso-2,3-dimethylbutane-1,4-diol and its Diacetate, Synthesis of Scalemic (-)Lasiol2002In: Russ. Chem. Bull. Int. Ed., no 14, p. 153-Article in journal (Other scientific)
  • 2645.
    Vasse, Jean Luc
    et al.
    KTH, Superseded Departments, Chemistry.
    Stranne, Robert
    KTH, Superseded Departments, Chemistry.
    Zalubovskis, Raivis
    KTH, Superseded Departments, Chemistry.
    Gayet, Carole
    KTH, Superseded Departments, Chemistry.
    Moberg, Christina
    KTH, Superseded Departments, Chemistry.
    Influence of steric symmetry and electronic dissymmetry on the enantioselectivity in palladium-catalyzed allylic substitutions2003In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 68, no 8, p. 3258-3270Article in journal (Refereed)
    Abstract [en]

    Chiral P,N-ligands with pseudo-C2 and pseudo-Cs symmetry based on chiral pyrrolidine and phospholane rings or on dinaphthatodihydroazepino and dinaphthatodihydrophosphepino moieties were prepared and assessed in the palladium-catalyzed allylic substitutions of allylic acetates. Higher selectivity was achieved with pseudo-C2-symmetric ligands based on the binaphthyl skeleton than with the analogous C2-symmetric P,P- and N,N-analogues. Pseudo-C2-type ligands had properties superior to those of pseudo-meso-type ligands when 1,3-diphenyl-2-propenyl acetate was used as a substrate, whereas the reverse situation was found for 3-cyclohexenyl acetate. Chirally flexible ligands, prepared by substitution of one of the rigid binaphthyl skeletons for a flexible biphenyl system, were found to induce chirality to the same extent as a 1:1 mixture of the rigid ligands.

  • 2646. Vasur, Jonas
    et al.
    Kawai, Rie
    Jonsson, K. Hanna M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Engström, Åke
    Frank, Martin
    Andersson, Evalena
    Hansson, Henrik
    Forsberg, Zarah
    Igarashi, Kiyohiko
    Samejima, Masahiro
    Sandgren, Mats
    Ståhlberg, Jerry
    Synthesis of cyclic β-glucan using Laminarinase 16A glycosynthase mutant from the basidiomycete Phanerochaete chrysosporium2010In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, no 5, p. 1724-1730Article in journal (Refereed)
    Abstract [en]

    Glycosynthases are precise molecular instruments for making specifically linked oligosaccharides. X-ray crystallography screening of ligands bound to the 1,3(4)-β-d-glucanase nucleophile mutant E115S of Phanerochaete chrysosporium Laminarinase 16A (Lam16A) showed that laminariheptaose (L7) bound in an arch with the reducing and nonreducing ends occupying either side of the catalytic cleft of the enzyme. The X-ray structure of Lam16A E115S in complex with α-laminariheptaosyl fluoride (αL7F) revealed how αL7F could make a nucleophilic attack upon itself. Indeed, when Lam16A E115S was allowed to react with αL7F the major product was a cyclic β-1,3-heptaglucan, as shown by mass spectrometry. NMR confirmed uniquely β-1,3-linkages and no reducing end. Molecular dynamics simulations indicate that the cyclic laminariheptaose molecule is not completely planar and that torsion angles at the glycosidic linkages fluctuate between two energy minima. This is the first report of a glycosynthase that joins the reducing and nonreducing ends of a single oligosaccharide and the first reported synthesis of cyclic β-glucan.

  • 2647.
    Vazquez-Romero, Ana
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bermejo Gómez, Antonio
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Acid- and Iridium-Catalyzed Tandem 1,3-Transposition/3,1-Hydrogen Shift/Chlorination of Allylic Alcohols2015In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 5, no 2, p. 708-714Article in journal (Refereed)
    Abstract [en]

    A method for the selective synthesis of alpha-chlorocarbonyls from allylic alcohols is presented. The reaction occurs through an acid- and iridium-catalyzed tandem process that combines a 1,3-transposition, a 3,1-hydrogen shift, and a chlorination process, and can be applied to a wide range of alpha-aromatic and heteroaromatic secondary allylic alcohols. Saturated non-chlorinated ketones or other side-products derived from overchlorination were not detected.

  • 2648. Veiga, Alberte
    et al.
    Arenz, Sven
    Erdelyi, Mate
    N-Arylation of Protected Azamacrocycles2013In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, Vol. 45, no 6, p. 777-784Article in journal (Refereed)
    Abstract [en]

    A rapid method for efficient palladium-catalyzed N-aryl­ation of polynitrogenated macrocycles is presented. Its applicability for functionalization of protected azamacrocycles of various sizes with substituted aryl bromides of optional electronic properties is demonstrated. The compatibility of the protocol with common N-protecting schemes as well as the impact of electronic versus steric factors is discussed. Using a commercially available catalytic system and easily available alkoxide or phenoxide base, the method provides moderate to excellent yields of N-arylated azamacrocycles (45–96%).

  • 2649.
    Velikyan, I.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Lendvai, G.
    Välilä, M.
    Roivainen, A.
    Bergström, M.
    Långström, B.
    68Ga-Labelling and Characterization of 17-mer Antisense Oligoncleotides Complementary to Human K-ras Oncogene2003In: BMC Open house, BMC Uppsala, 2003Conference paper (Other scientific)
  • 2650.
    Velikyan, Irina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Synthesis, Characterization and Application of 68Ga-labelled Peptides and Oligonucleotides2004Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The positron emitting 68Ga radionuclide (T1/2 = 68 min) has the potential of practical interest for clinical PET. The metallic cation, 68Ga3+, is suitable for complexation reactions with chelators either naked or conjugated with macromolecules such as peptides and oligonucleotides. Such labeling procedures require pure and concentrated radiometal preparations, which cannot be sufficiently fulfilled by the presently available 68Ge/68Ga generator eluate. This thesis presents a method to increase the concentration and purity of 68Ga obtained from a commercial 68Ge/68Ga generator. DOTATOC (DOTA = 1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid, TOC = D-Phe1-Tyr3–Octreotide) was used as a test molecule for comparing the labeling properties of different 68Ga preparations. In addition, DOTA-RDG (RGD = Cys2-6; c[CH2CO-Lys(DOTA)-Cys-Arg-Gly-Asp-Cys-Phe-Cys]-CCX6-NH2) and NODAGATATE (NODAGA = 1,4,7-triazacyclononane-1,4,7-triacetic, TATE = Tyr3 - Octreotate) were used to prove the concept. The use of the concentrated and purified 68Ga eluate along with microwave activation allowed quantitative 68Ga-labelling of peptide conjugates of ≤1 nanomolar quantities within 10 min. The specific radioactivity of the radiolabelled peptides was improved by a factor of >100 compared to previously applied techniques using non-treated generator eluate and conventional heating. A commercial 68Ge/68Ga generator in combination with this method for purification, concentration and microwave activated labeling resulted in a kit technology for 68Ga-tracer production.Four 17-mer oligonucleotides modified and functionalised with an hexylamine group in the 3'- or 5'- position were conjugated with DOTA and labelled with 68Ga using microwave activation. Chemical modification of the oligonucleotide backbone or sugar moiety did not influence the labelling nor the hybridisation ability of the oligonucleotides. However, the radioactivity organ biodistribution in rats differed dependent on the oligonucleotide structure. This indicated that metabolism and non-specific binding were affected by the backbone and sugar moiety structure.

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