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  • 101.
    BERGER, RA
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Oorganisk kemi.
    ON THE SYMMETRY OF LICUO21995In: J Solid State Chem, Vol. 114, p. 590-591Article in journal (Refereed)
    Abstract [en]

    Utsumi et al., J. Solid State Chem. 107, 507, 1993, claim that LiCuO2 transforms from an orthorhombic modification to a monoclinic one by applying pressure. This interpretation is disputed on the basis of evidence from X-ray and neutron diffraction refinements which show that LiCuO2 is already monoclinic (NaCuO2 structure type) at ambient pressure.

  • 102.
    Berger, Rolf
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Oorganisk kemi.
    Bucur, Romulus V.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Materials Chemistry, Inorganic Chemistry. Oorganisk kemi.
    Diffusion in Copper Sulphides: An experimental study of chalcocite, chalcopyrite and bornite1996Report (Other scientific)
    Abstract [en]

    Diffusion measurements on three copper-containing sulphides have been performed by an electrochemical potentiometric method. -- The diffusion coefficient for chalcocite is in good agreement with values found previously, and a reasonable agreement is also found for chalcopyrite and bornite when our data are compared with values acquired at much higher temperatures with a different technique. The activation energies are remarkably similar for the three sulphides, considering that their relative errors are of a 10% magnitude, which indicates that the bonding strengths and the diffusion mechanisms are similar.

  • 103.
    Berger, Rolf
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Oorganisk kemi.
    Bucur, Romulus V.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Oorganisk kemi.
    Electrochemistry applied on the TlCu3Se2/TlCu2Se2 phase transformation1992In: Materials Research Bulletin, Vol. 27, p. 439-446Article in journal (Refereed)
    Abstract [en]

    PreviousLy, chemical oxidation of TlCu3X2 (X= S,Se) as a powder immersed in ammonia solution effectuated a phase transformation into the p-metal TlCu2X2. In order to explore whether the small grain size and intimate contact with the liquid phase were imperative, we introduce an electrochemical method with the starting phase as a polished rotating electrode.---The microstructures of polished electrode surfaces indicate that processes within the solid rather than in the interface with the electrolyte are important. The slower and less efficient reduction process may be explained from topotactic symmetry considerations.

  • 104.
    Berger, Rolf
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Oorganisk kemi.
    Dronskowski, Richard
    Norén, Lasse
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Oorganisk kemi.
    Copper extraction in TlCu3S2 -- a neutron diffraction and electronic calculation study1994In: J Solid State Chem., Vol. 112, p. 120-125Article in journal (Refereed)
    Abstract [en]

    The mechanism of the TlCu3S2/TlCu2S2 phase transformation has been studied experimentally by neutron diffraction and theoretically by three-dimensional Hueckel band calculations. Experiments show that only one of the sites is attacked during oxidative extraction of copper from TlCu3S2, the site that according to the calculations should be the most vulnerable. The results support a previously presented transformation mechanism model based on topotaxy.

  • 105.
    Berger, Rolf
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Oorganisk kemi.
    Eriksson, Lars
    Meerschaut, Alain
    The Crystal Structure of TlCu5Se31990In: Journal of Solid State Chemistry, Vol. 87, p. 283-288Article in journal (Refereed)
    Abstract [en]

    The crystal structure of copper-deficient TlCu5Se3 has been refined from single-crystal diffraction data. The previously suggested new structure type was confirmed with agreement factors R(F)= 0.033 and R(wF)= 0.035. The symmetry is tetragonal, space-group P4(2)/mnm (136).

  • 106. Berglof, T
    et al.
    Jonsall, G
    Markides, KE
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Selectivity in supercritical fluid extraction: Recovery of pesticides from model matrices1999In: JOURNAL OF CHROMATOGRAPHIC SCIENCE, ISSN 0021-9665, Vol. 37, no 10, p. 400-406Article in journal (Refereed)
  • 107.
    Berglöf, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Supercritical Fluid Extraction (SFE) in Environmental Analysis1996Licentiate thesis, monograph (Other academic)
  • 108.
    Bergman, Jan
    et al.
    CNT, DEPT ORGAN CHEM, S-14157 HUDDINGE, SWEDEN .
    Lidgren, Göran
    ROYAL INST TECHNOL, DEPT ORGAN CHEM, S-10044 STOCKHOLM 70, SWEDEN.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Synthesis and Reactions of Oxazolones from L‑Tryptophan and α‑Haloacetic Anhydrides1992In: Bulletin des Sociétés chimiques belges, ISSN 0037-9646, Vol. 101, no 7, p. 643-660Article in journal (Refereed)
    Abstract [en]

    Optically active 5(4H)-oxazolones have been synthesized from L-tryptophan and an excess of trifluoro-, trichloro-, and dichloroacetic anhydrides. Some of the 5(4H)-xazolones have been further transformed to the isomeric 5(2H)-oxazolones as well as oxazolones with exocyclic double bonds. Treatment of the various oxazolones under hydrolytic, acidic and Friedel-Crafts acylation conditions gave indole-3-pyruvic acid, alpha,beta-dehydrotryptophans, beta-carbolines as well as the functionalized cyclopentanoindole 32. Treatment of the 4-(3-indolylmethyl)-2-trifluoromethyl-5(2H)-oxazolone (17) with trifluoroacetic acid gave the 3,4-bridged azepinoindole 35.

  • 109.
    Bergquist, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    From MALDI-TOF MS to Two Dimensional CE-FTICR-MS of Proteins in Spinal Fluid2002In: Molecular Testing in Laboratory Medicine, 2002, p. 171-172Chapter in book (Other academic)
  • 110.
    Bergquist, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    From molecule to man - using electrospray Fourier Transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) in proteomics2003In: ISMAS Silver Jubilee Symposium on Mass Spectrometry, 2003Chapter in book (Other academic)
  • 111.
    Bergquist, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    FTICR mass spectrometry in proteomics2003In: Current Opinion in Molecular Therapeutics, no 5, p. 310-314Article in journal (Refereed)
  • 112.
    Bergquist, J
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Andersen, O
    Westman, A
    Rapid method to characterize mutations in transthyretin in cerebrospinal fluid from familial amyloidotic polyneuropathy patients by use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry2000In: Clin. Chem., Vol. 46, no 9, p. 1293-1300Article in journal (Refereed)
  • 113.
    Bergquist, J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Ekman, R.
    The dynamics of the cell nucleus - Lymphocyte nuclei associated peptides studied by mass spectrometry and future peptidomic aspects2002In: Mass spectrometry and Hyphenated Techniques in Neuropeptide Research, John Wiley & Sons, N.Y. , 2002, Vol. Chapter 21, p. 519-553Chapter in book (Refereed)
  • 114.
    Bergquist, J
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Gobom, J
    Blomberg, A
    Roepstorff, P
    Ekman, R
    Identification of nuclei associated proteins by 2D-gel electrophoresis and mass spectrometry2001In: J. Neurosci. Meth., no 109, p. 3-11Article in journal (Refereed)
  • 115.
    Bergquist, J
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Ohlsson, B
    Tarkowski, A
    Nuclear factor-kB is involved in the catecholaminergic suppression of immunocompetent cells2000In: Neuroimmodulation, Vol. 917, p. 281-289Article in journal (Refereed)
  • 116.
    Bergquist, J.
    et al.
    ION PHYSICS. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Palmblad, M.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Wetterhall, M., Håkansson, P., Markides, K.E.
    Peptide mapping of proteins in human body fluids using electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry2002In: Mass. Spectrom. Reviews, no 21, p. 2-15Article in journal (Refereed)
  • 117.
    Bergquist, J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Sciubisz, A.
    Kaczor, A.
    Silberring, J.
    Catecholamines and methods for their identification and quantitation in biological tissues and fluids2002In: J. Neurosci. Meth., no 113, p. 1-13Article in journal (Refereed)
  • 118.
    Bergquist, J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Träskman-Bendz, L.
    Lindström, M.B.
    Ekman, R.
    Suicide-attempters having immunoglobulin G with affinity for dopamine in cerebrospinal fluid2002In: European Neuropsychopharmacology, no 12, p. 153-158Article in journal (Refereed)
  • 119.
    Bergson, G., Matsson, O.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Daniel Strömholm, The Svedberg och isotoperna2001In: Acta Academica Regiae Scientiarum Upsaliensis, ISSN ISBN 91-85832-14-6, Vol. 21, p. 53-60Article in journal (Other scientific)
  • 120.
    Bergstad, Katarina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Molecular oxygen and hydrogen peroxide as mild oxidants in catalytic oxidations: Applications to palladium and osmium catalysis1998Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis the use of molecular oxygen and hydrogen peroxide as mild oxidants in transition metal-catalyzed oxidations of organic substrates is discussed. The thesis is divided into three parts.

    In the first part the use of heteropolyacids as robust oxygen-activating agents for aerobic reoxidation of zerovalent palladium is described. This aerobic reoxidation system has been applied to two different palladium-catalyzed reactions, the allylic oxidation of cyclohexene and the 1,4-oxidation of conjugated dienes. It was demonstrated that the presence of a benzoquinone, which can act both as an electron-transfer mediator and a coordinating ligand in the intermediate palladium π-allyl complex, is of importance for efficient reactions.

    In the second part, studies of systems for mild oxidations of tertiary amines to amine N-oxides are described. It was found that a fully reduced N1,N5- dialkylblocked flavin catalyzes the H2O2 oxidation of tertiary amines, giving the amine N-oxides in good yields in fast reactions. The reduced flavin acts as a precursor of the active catalyst, which is generated in the presence of air. Co(salophen), another investigated potential catalyst, was found to form a 1:2 complex with N-methylmorpholine N-oxide (NMO). This catalyst-product complex may inhibit the amine oxidations.

    The final part deals with in situ generation of NMO from N-methylmotpholine (NMM) in the osmium-catalyzed dihydroxylation of olefins. In a model study it was demonstrated that mCPBA in the presence of catalytic amounts of NMM is an efficient reoxidant for osmium(VI) in the dihydroxylation. Further investigations showed that H2O2 is an excellent oxidant in osmium-catalyzed dihydroxylations where NMM and a flavin are employed as cocatalysts. Different cis diols were synthesized in good yields by this procedure.

  • 121.
    Bergstrom, M
    et al.
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Juhlin, C
    Department of Surgical Sciences.
    Bonasera, TA
    Sundin, A
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
    Rastad, J
    Department of Surgical Sciences.
    Åkerström, Göran
    Department of Surgical Sciences.
    Langstrom, B
    Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    PET imaging of adrenal cortical tumors with the 11beta-hydroxylase tracer11C-metomidate.2000In: J Nucl Med, Vol. 41, p. 275-Article in journal (Refereed)
  • 122.
    Bergström, M.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Awad, R.
    Estrada, S., Malman, J.
    Lu, L., Lendvai, G.
    Bergström-Pettermann, E., Långström, B.
    Autoradiography with positron emitting isotopes in positron emission tomography tracer discovery2003In: Mol Imaging Biol., Vol. 6, no 460, p. 390-396Article in journal (Refereed)
  • 123. Bergström, M.
    et al.
    Fasth, K-J.
    Kilpatrick, G.
    Ward, P.
    Cable, K M.
    Wipperman, M D.
    Sutherland, D R.
    Långström, B.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Brain uptake and receptor binding of two (11C)labelled selective high affinity NK1-antagonists, GR203040 and GR205171 - PET studies in rhesus monkey.2000In: Neuropharmacology, ISSN 0028-3908, Vol. 39, no 4, p. 664-670Article in journal (Refereed)
  • 124. Bergström, Mats
    et al.
    Muhr, Carin
    Lundberg, Per-Ola
    Bergström, Kjell
    Lundkvist, Hans
    Antoni, Gunnar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Fasth, Karl-Johan
    Långström, Bengt
    Amino acids distribution and metabolism in pituitary adenomas using positron emission  tomography with 11C-L- and D-methionine.1987In: Journal of computer assisted tomography, ISSN 0363-8715, E-ISSN 1532-3145, Vol. 11, p. 384-389Article in journal (Refereed)
  • 125.
    Bergström, Sara
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Analytisk kemi.
    Development of Integrated Micro-Analytical Systems2003Licentiate thesis, monograph (Other scientific)
  • 126.
    Bergström, Sara
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Integrated Micro-Analytical Tools for Life Science2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Advances in life science require knowledge of active molecules in complex biological systems. These molecules are often only present for a certain time and at limited concentrations. Integrated micro-analytical tools for sampling, separation and mass spectrometric (MS) detection would meet these requests and are therefore continuously gaining interest. An on-line coupling of analytical functions provides shorter analysis time and less manual sample handling. In this thesis, improved compatibility of microdialysis sampling and multidimensional separations coupled to MS detection are developed and discussed.

    Microdialysis was used in vitro for determination of the non-protein bound fraction of the drug ropivacaine. The sampling unit was coupled on-line to capillary column liquid chromatography (LC) followed by ultraviolet or MS detection. For MS detection, the system was extended with a desalting step and an addition of internal standard. A method for MS screening of microdialysates, collected in vivo, was also developed. The method involved sampling and measurements of the chemical pattern of molecules that generally are ignored in clinical investigations. Chemometric tools were used to extract the relevant information and to compare samples from stimulated and control tissues.

    Complex samples often require separation in more than one dimension. On-line interfaces for sample transfer between LC and capillary electrophoresis (CE) were developed in soft poly(dimethylsiloxane) (PDMS). MS detection in the LC-CE system was optimised on frequent sampling of the CE peak or on high resolution in mass spectra using time-of-flight (TOF)MS or Fourier transform ion cyclotron resonance (FTICR)MS, respectively. Aspects on electrode positioning in the LC-CE interface led to development of an on-column CE electrode. A successful method for deactivation of the PDMS surface using a polyamine polymer was also developed. The systems were evaluated using peptides and proteins, molecules that are gaining increased attention in bioscience, and consequently also in chemical analysis.

    List of papers
    1. Determination of the free concentration of ropivacaine in plasma by packed capillary liquid chromatography: A comparison of ultrafiltration and microdialysis as sample preparation methods
    Open this publication in new window or tab >>Determination of the free concentration of ropivacaine in plasma by packed capillary liquid chromatography: A comparison of ultrafiltration and microdialysis as sample preparation methods
    2001 (English)In: Journal of Microcolumn Separations, ISSN 1040-7685, E-ISSN 1520-667X, Vol. 13, no 5, p. 197-201Article in journal (Refereed) Published
    Abstract [en]

    In this study, ultrafiltration and microdialysis have been compared as sample preparation methods to separate the free fraction of ropivacaine from the protein bound in 150 μL plasma. A liquid chromatographic system with packed capillary columns (0.2 mm internal diameter) was used to enhance sensitivity when analyzing the small sample volumes obtained after the ultrafiltration and the microdialysis. The microdialysis was performed with probes of our own construction, and to save analysis time, the microdialysis sampling was coupled on-line to the liquid chromatographic system. The reduction of back pressure in the microdialysis outlet tube and in the injector was found to be essential. The free fraction obtained with each method was equivalent: both gave a free fraction of 6%.

    Keywords
    microdialysis, ultrafiltration, free fraction, ropivacaine, capillary liquid chromatography
    National Category
    Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-93670 (URN)10.1002/mcs.1042 (DOI)
    Available from: 2005-10-28 Created: 2005-10-28 Last updated: 2017-12-14Bibliographically approved
    2. On-line coupling of microdialysis to packed capillary column liquid chromatography-tandem mass spectrometry demonstrated by measurement of free concentrations of ropivacaine and metabolite from spiked plasma samples
    Open this publication in new window or tab >>On-line coupling of microdialysis to packed capillary column liquid chromatography-tandem mass spectrometry demonstrated by measurement of free concentrations of ropivacaine and metabolite from spiked plasma samples
    2002 (English)In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 775, no 1, p. 79-87Article in journal (Refereed) Published
    Abstract [en]

    An on-line coupling of microdialysis to a packed capillary column switching liquid chromatographic system (0.2 mm I.D.) and mass spectrometric detection was developed. The microdialysates were collected in the loop of the first of three valves, coupled in direct series. A deuterated internal standard was added on-line by the middle valve and the third valve operated both a pre-column, for desalting of the physiological buffer used in the sampling procedure, and a separation column. The on-line system was used to study free concentrations of ropivacaine and its metabolite (PPX) in human plasma samples. The analytes were detected by electrospray ionization in a tandem mass spectrometer operating in multiple reaction monitoring mode. The free fractions of ropivacaine (200 nM total concentration) and PPX (20 nM total concentration) in spiked plasma samples were 12±3 and 47±5% (±standard deviation for day-to-day variations, n=3), respectively.

    National Category
    Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-93671 (URN)10.1016/S1570-0232(02)00280-5 (DOI)
    Available from: 2005-10-28 Created: 2005-10-28 Last updated: 2017-12-14Bibliographically approved
    3. Screening of microdialysates using on-line desalting and mass spectrometric detection
    Open this publication in new window or tab >>Screening of microdialysates using on-line desalting and mass spectrometric detection
    Show others...
    In: J. Chromatogr. AArticle in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-93672 (URN)
    Available from: 2005-10-28 Created: 2005-10-28Bibliographically approved
    4. On-column polymer-imbedded graphite inlet electrode for capillary electrophoresis coupled on-line with flow injection analysis in a poly(dimethylsiloxane) interface
    Open this publication in new window or tab >>On-column polymer-imbedded graphite inlet electrode for capillary electrophoresis coupled on-line with flow injection analysis in a poly(dimethylsiloxane) interface
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    2003 (English)In: Electrophoresis, ISSN 0173-0835, E-ISSN 1522-2683, Vol. 24, no 11, p. 1723-1729Article in journal (Refereed) Published
    Abstract [en]

    A method for coupling an electrophoretic driven separation to a liquid flow, using conventional fused-silica capillaries and a soft polymeric interface is presented. A novel design of the electrode providing high voltage to the electrophoretic separation was also developed. The electrode consisted of a conductive polyimide/graphite imbedded coating immobilized onto the capillary electrophoresis (CE) column inlet. This integrated electrode gave the same separation performance as a commonly used platinum electrode. The on-column electrode also showed good electrochemical stability in chronoamperometric experiments. In addition, with this electrode design, the electrode position relative to the inlet end of the CE column will always be constant and well defined. The on-line flow injection analysis (FIA)-CE system was used with electrospray ionization (ESI)-time of flight (TOF)-mass spectrometry detection. The preparation of the PDMS (poly(dimethylsiloxane)) interface for FIA-CE is described in detail and used for initial tests of the on-column polymer-imbedded graphite inlet electrode. In this interface, a pressure-driven liquid flow, a make up CE electrolyte and a CE column inlet meet in a two-level cross (95 μm ID) in the PDMS structure, enabling independent flow characterization.

    Keywords
    Capillary electrophoresis, Flow injection, Hyphenation, On-column electrode, Poly(dimethylsiloxane)
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-94267 (URN)10.1002/elps.200305362 (DOI)
    Available from: 2006-04-07 Created: 2006-04-07 Last updated: 2017-12-14Bibliographically approved
    5. Development of a poly(dimethylsiloxane) interface for on-line capillary column liquid chromatography-capillary electrophoresis coupled to sheathless electrospray ionization time-of-flight mass spectrometry
    Open this publication in new window or tab >>Development of a poly(dimethylsiloxane) interface for on-line capillary column liquid chromatography-capillary electrophoresis coupled to sheathless electrospray ionization time-of-flight mass spectrometry
    2003 In: Anal. Chem., ISSN 0003-2700, Vol. 75, no 20, p. 5461-5467Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-93674 (URN)
    Available from: 2005-10-28 Created: 2005-10-28Bibliographically approved
    6. Polyamine deactivation of integrated poly(dimethylsiloxane) structures investigated by radionuclide imaging and capillary electrophoresis experiments
    Open this publication in new window or tab >>Polyamine deactivation of integrated poly(dimethylsiloxane) structures investigated by radionuclide imaging and capillary electrophoresis experiments
    Show others...
    2005 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 77, no 3, p. 938-942Article in journal (Refereed) Published
    Abstract [en]

    The poly(dimethylsiloxane) (PDMS) material provides a number of advantageous features, such as flexibility, elasticity, and transparency, making it useful in integrated analytical systems. Hard fused-silica capillary structures and soft PDMS channels can easily be combined by a tight fit, which offers many alternatives for structure combinations. PDMS and fused silica are in different ways prone to adsorption of low levels of organic compounds. The need for modification of the inner wall surface of PDMS channels may often be necessary, and in this paper, we describe an easy and effective method using the amine-containing polymer PolyE-323 to deactivate both fused-silica and PDMS surfaces. The adsorption of selected peptides to untreated surfaces was compared to PolyE-323-modified surfaces, using both radionuclide imaging and capillary electrophoresis experiments. The polyamine modification displayed a substantially reduced adsorption of three hydrophobic test peptides compared to the native PDMS surface. Filling and storage of aqueous solution were also possible in PolyE-323-modified PDMS channels. In addition, hybrid microstructures of fused silica and PDMS could simultaneously be deactivated in one simple coating procedure.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-93675 (URN)10.1021/ac0492618 (DOI)
    Available from: 2005-10-28 Created: 2005-10-28 Last updated: 2017-12-14Bibliographically approved
    7. A simplified multidimensional approach for analysis of complex biological samples: on-line LC-CE-MS
    Open this publication in new window or tab >>A simplified multidimensional approach for analysis of complex biological samples: on-line LC-CE-MS
    Show others...
    2006 (English)In: The Analyst, ISSN 0003-2654, E-ISSN 1364-5528, Vol. 131, no 7, p. 791-798Article in journal (Refereed) Published
    Abstract [en]

    Information on protein expression, disease biomarkers or surrogate markers and genetic disorders can nowadays be achieved from analysis of complex biological samples by liquid separation coupled to mass spectrometric (MS) detection. This paper describes fast multidimensional separation by on-line liquid chromatography (LC) and capillary electrophoresis (CE), followed by electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FTICR) MS detection. This detector provides ultrahigh resolution of the detected ions, mass accuracy at the ppm-level and high sensitivity. Most of the challenge of this system lies in the development of a new interface for the on-line coupling of LC to CE. The interface developed in poly(dimethylsiloxane) provides a RSD for injection repeatability of <3.5% and surface control for unspecific binding by deactivation with a cationic polymer, PolyE-323. We have evaluated the interface, as well as the overall system, with respect to robustness and deconvolution ability. Sequence coverage for bovine serum albumin (BSA) of 93% showed a high recovery of sample in the different transfer steps through the system. The detection limit for identification is 277 ng mL−1 (or 280 nM) on average for peptides. In the future, we expect LC-CE-MS to be a novel strategy for elucidating the chemistry of biological matrices.

    National Category
    Analytical Chemistry
    Identifiers
    urn:nbn:se:uu:diva-80932 (URN)10.1039/b601660j (DOI)
    Available from: 2006-06-29 Created: 2006-06-29 Last updated: 2017-12-14Bibliographically approved
    8. Poly(dimethylsiloxane)-Based Microchip for Two-Dimensional Solid-Phase Extraction-Capillary Electrophoresis with an Integrated Electrospray Emitter Tip
    Open this publication in new window or tab >>Poly(dimethylsiloxane)-Based Microchip for Two-Dimensional Solid-Phase Extraction-Capillary Electrophoresis with an Integrated Electrospray Emitter Tip
    Show others...
    2005 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 77, no 16, p. 5356-5363Article in journal (Refereed) Published
    Abstract [en]

    A microchip in poly(dimethylsiloxane) (PDMS) for in-line solid-phase extraction-capillary electrophoresis-electrospray ionization-time-of-flight mass spectrometry (SPE-CE-ESI-TOF-MS) has been developed and evaluated. The chip was fabricated in a novel one-step procedure where mixed PDMS was cast over steel wires in a mold. The removed wires defined 50-um cylindrical channels. Fused-silica capillaries were inserted into the structure in a tight fit connection. The inner walls of the inserted fused-silica capillaries and the PDMS microchip channels were modified with a positively charged polymer, PolyE-323. The chip was fabricated in a two-level cross design. The channel at the lower level was packed with 5-um hyper-cross-linked polystyrene beads acting as a SPE medium used for desalting. The upper level channel acted as a CE channel and ended in an integrated emitter tip coated with conducting graphite powder to facilitate the electrical contact for sheathless ESI. An overpressure continuously provided fresh CE electrolyte independently of the flows in the different levels. Further studies were carried out in order to investigate the electrophoretic and flow rate properties of the chip. Finally, six-peptide mixtures, in different concentrations, dissolved in physiological salt solution was injected, desalted, separated, and sprayed into the mass spectrometer for analysis with a limit of detection in femtomole levels.

    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-74074 (URN)10.1021/ac050495g (DOI)16097780 (PubMedID)
    Available from: 2005-08-26 Created: 2005-08-26 Last updated: 2017-12-14Bibliographically approved
  • 127.
    Bergström, Sara K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Edenwall, Niklas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Lavén, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Velikyan, Irina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Organic Chemistry.
    Markides, Karin E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Polyamine deactivation of integrated poly(dimethylsiloxane) structures investigated by radionuclide imaging and capillary electrophoresis experiments2005In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 77, no 3, p. 938-942Article in journal (Refereed)
    Abstract [en]

    The poly(dimethylsiloxane) (PDMS) material provides a number of advantageous features, such as flexibility, elasticity, and transparency, making it useful in integrated analytical systems. Hard fused-silica capillary structures and soft PDMS channels can easily be combined by a tight fit, which offers many alternatives for structure combinations. PDMS and fused silica are in different ways prone to adsorption of low levels of organic compounds. The need for modification of the inner wall surface of PDMS channels may often be necessary, and in this paper, we describe an easy and effective method using the amine-containing polymer PolyE-323 to deactivate both fused-silica and PDMS surfaces. The adsorption of selected peptides to untreated surfaces was compared to PolyE-323-modified surfaces, using both radionuclide imaging and capillary electrophoresis experiments. The polyamine modification displayed a substantially reduced adsorption of three hydrophobic test peptides compared to the native PDMS surface. Filling and storage of aqueous solution were also possible in PolyE-323-modified PDMS channels. In addition, hybrid microstructures of fused silica and PDMS could simultaneously be deactivated in one simple coating procedure.

  • 128.
    Bergström, Sara K
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry, Analytical Chemistry.
    Goiny, Michel
    Danielsson, Rolf
    Ungerstedt, Urban
    Andersson, Marit
    Markides, Karin E
    Screening of microdialysates using on-line desalting and mass spectrometric detectionIn: J. Chromatogr. AArticle in journal (Refereed)
  • 129.
    Bergström, Sara K.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Markides, Karin E.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    On-line coupling of microdialysis to packed capillary column liquid chromatography-tandem mass spectrometry demonstrated by measurement of free concentrations of ropivacaine and metabolite from spiked plasma samples2002In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 775, no 1, p. 79-87Article in journal (Refereed)
    Abstract [en]

    An on-line coupling of microdialysis to a packed capillary column switching liquid chromatographic system (0.2 mm I.D.) and mass spectrometric detection was developed. The microdialysates were collected in the loop of the first of three valves, coupled in direct series. A deuterated internal standard was added on-line by the middle valve and the third valve operated both a pre-column, for desalting of the physiological buffer used in the sampling procedure, and a separation column. The on-line system was used to study free concentrations of ropivacaine and its metabolite (PPX) in human plasma samples. The analytes were detected by electrospray ionization in a tandem mass spectrometer operating in multiple reaction monitoring mode. The free fractions of ropivacaine (200 nM total concentration) and PPX (20 nM total concentration) in spiked plasma samples were 12±3 and 47±5% (±standard deviation for day-to-day variations, n=3), respectively.

  • 130.
    Bergström, Sara K
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Samskog, Jenny
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Markides, Karin E
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Development of a Poly(dimethylsiloxane) Interface for On-Line Capillary Column Liquid Chromatography: Capillary Electrophoresis Coupled to Sheathless Electrospray Ionization Time-of-Flight Mass Spectrometry2003In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 75, no 20, p. 5461-5467Article in journal (Refereed)
    Abstract [en]

    An interface in elastomeric poly(dimethylsiloxane) (PDMS) for on-line orthogonal coupling of packed capillary liquid chromatography (LC) (i.d. = 0.2 mm) with capillary electrophoresis (CE) in combination with sheathless electrospray ionization (ESI) time-of-flight mass spectrometric (TOFMS) detection is presented. The new interface has a two-level design, which in combination with a continuous CE electrolyte flow through the interface provides integrity of the LC effluent and the CE separation until an injection is desired. The transparent and flexible PDMS material was found to have a number of advantages when combined with fused silica column technology, including ease to follow the process and ease to exchange columns. By combining conventional microscale systems of LC, CE, and ESI−MS, respectively, the time scales of the individual dimensions were harmonized for optimal peak capacity per unit time. The performance of the LC−CE−TOFMS system was evaluated using peptides as model substances. A S/N of about 330 was achieved for leucine-enkephaline from a 0.5 μL LC injection of 25 μg/mL peptide standard.

  • 131.
    Bergström, Sara K
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry, Analytical Chemistry.
    Samskog, Jenny
    Markides, Karin E
    Development of a poly(dimethylsiloxane) interface for on-line capillary column liquid chromatography-capillary electrophoresis coupled to sheathless electrospray ionization time-of-flight mass spectrometry2003In: Anal. Chem., ISSN 0003-2700, Vol. 75, no 20, p. 5461-5467Article in journal (Refereed)
  • 132.
    Bergström, S.K.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Samskog, J.
    Markides, K.E.
    Development of a Poly(dimethylsiloxane) Interface for On-Line Capillary Column Liquid Chromatography-Capillary Electrophoresis Coupled to Sheathless Electrospray Ionization Time-of-Flight Mass Spectrometry2003In: Anal. Chem., no 75, p. 5461-5467Article in journal (Refereed)
  • 133.
    Bergström, Örjan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Lithium-ion insertion in a V6O13 cathode1998Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The transition metal oxide V6O13 is a promising cathode material for high-capacity lithium-polymer batteries in conjunction with a lithium-metal anode. The electro-chemical behaviour of V6O13 has its origin in the ability of the vanadium ions to change their-oxidation states, combined with the open nature of its crystal structure which allows lithium ions to diffuse through it. When incorporated into the cathode, the material passes through a series of lithiated phases as the battery is discharged. Inthis thesis, structure-property relationships of these lithiated phases have been studied. The techniques used have been in situ X-ray powder diffraction and single-crystal X-ray diffraction on electrochemically lithiated samples, in combination with electrochemical cycling.

    Five different lithiated phases were identified : LixV6O13 for x = 0.5, 1.0, 2.0, 3.0 and 6.0 at potentials 2.78, 2.68, 2.52, 2.45 and 2.00V vs. Li/Li+, respectively. The structures of the x = 0, 2.0 and 3.0 phases have been investigated using single-crystal techniques; deformation electron density refinement has been performed for the x=0 and 2.0 phases. The reduction (from V5+ to V4+) of one of the threeindependent vanadium atoms (V2) in the asymmetric unit can be identified with some degree of certainty as Li2V6O13 is formed. On this basis, a proposal is made for the complete sequence of vanadium oxidation-state changes for the entire lithium insertion process.

  • 134.
    Berlin, S
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Engman, L
    A radical cyclization route to pyrrolidines based on conjugate addition to electron deficient phenylselenenylalkenes2000In: TETRAHEDRON LETTERS, ISSN 0040-4039, Vol. 41, no 19, p. 3701-3704Article in journal (Refereed)
    Abstract [en]

    alpha-Phenylselenenyl-alpha,beta-unsaturated esters, amides, ketones, nitriles and sulfones were prepared by zinc chloride promoted chloroselenation/dehydrochlorination of the corresponding alpha,beta-unsaturated compounds. After Michael addition of allyl

  • 135.
    Berlin, S.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Ericsson, C
    Engman, L
    Construction of Tetrahydrofuran-3-ones from Readily Available Organochalcogen Precursors via Radical Carbonylation/Reductive Cyclization2002Article in journal (Other scientific)
  • 136.
    Berlin, S
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Ericsson, C
    Engman, L.
    Radical Carbonylation/Reductive Cyclization for the Construction of Tetrahydrofuran-3-ones and Pyrrolidin-3-ones2003In: J. Org. Chem., no 68, p. 8386-Article in journal (Refereed)
  • 137.
    Berlin, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Construction of Five-Membered Heterocycles via Radical Cyclization2001Licentiate thesis, monograph (Other scientific)
  • 138.
    Berlin, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Construction of Five-Membered Heterocyclic Compounds via Radical Cyclization2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis describes how radical cyclization chemistry can be applied for the construction of heterocyclic compounds.

    In the first part, a series of electron deficient α-phenylselenenylalkenes were prepared via a PhSeCl-addition/HCl-elimination sequence. Allyl- and propargylamines readily underwent conjugate addition to these species to produce pyrrolidines or dihydropyrrol derivatives, after triethylborane initiated reductive radical cyclization in the presence of tris(trimethylsilyl)silane.

    The second part describes a convergent synthesis of the pineal hormone melatonin. The indole nucleus is secured via a tris(trimethylsilyl)silane mediated 5-exo radical cyclization. The protocol provides convenient and simple access to compounds useful for studies of biological activity and structure activity relationships.

    The third part describes construction of substituted tetrahydrofuran-3-ones and pyrrolidin-3-ones. Regioselective ring-opening of epoxides or aziridines with benzeneselenolate/tellurolate, followed by Michael addition to electron deficient alkynes afforded the corresponding O/N-vinylated compounds. The tetrahydrofuran-3-ones and pyrrolidin-3-ones were secured via radical carbonylation/reductive cyclization using pressurized carbon monoxide (80 atm).

    The fourth part is concerned with the effect of an N-protecting group on the cyclization of 2-substituted-3-aza-5-hexenyl radicals. Relative energies for reactants and transition states were determined using density functional calculations. Reactant and transition state conformers leading to cis-product were lower in energy than those leading to trans-product. The results can be explained by the unfavorable 1,2-strain present in chair-equatorial and boat-equatorial conformers.

    List of papers
    1. A Radical Cyclization Route to Pyrrolidines Based on Conjugate Addition to Electron Deficient Phenylselenenylalkenes
    Open this publication in new window or tab >>A Radical Cyclization Route to Pyrrolidines Based on Conjugate Addition to Electron Deficient Phenylselenenylalkenes
    2000 In: Tetrahedron Letters, Vol. 41, no 19, p. 3701-3704Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-90418 (URN)
    Available from: 2003-05-12 Created: 2003-05-12Bibliographically approved
    2. Efficient Route to the Pineal Hormone Melatonin by Radical-Based Indole Synthesis
    Open this publication in new window or tab >>Efficient Route to the Pineal Hormone Melatonin by Radical-Based Indole Synthesis
    2003 (English)In: Synthetic Communications, ISSN 0039-7911, E-ISSN 1532-2432, Vol. 33, no 20, p. 3631-3641Article in journal (Refereed) Published
    Abstract [en]

    The hormone melatonin, which is known to have a range of important biological effects, has been prepared in a high-yielding route that features formation of the indole nucleus by radical cyclization. Mediation of the radical cyclization by tristrimethylsilylsilane (TTMSS) is more efficient than by N-ethylpiperidine hypophosphite.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-90419 (URN)10.1081/SCC-120024751 (DOI)
    Available from: 2003-05-12 Created: 2003-05-12 Last updated: 2017-12-14Bibliographically approved
    3. Construction of Tetrahydrofuran-3-ones from Readily Available Organochalcogen Precursors via Radical Carbonylation/Reductive Cyclization
    Open this publication in new window or tab >>Construction of Tetrahydrofuran-3-ones from Readily Available Organochalcogen Precursors via Radical Carbonylation/Reductive Cyclization
    2002 In: Organic Letters, Vol. 4, p. 3-6Article in journal (Refereed) Published
    Identifiers
    urn:nbn:se:uu:diva-90420 (URN)
    Available from: 2003-05-12 Created: 2003-05-12Bibliographically approved
    4. Radical Carbonylation/Reductive Cyclization for the Construction of Tetrahydrofuran-3-ones and Pyrrolidin3-0nes
    Open this publication in new window or tab >>Radical Carbonylation/Reductive Cyclization for the Construction of Tetrahydrofuran-3-ones and Pyrrolidin3-0nes
    In: Journal of Organic ChemistryArticle in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-90421 (URN)
    Available from: 2003-05-12 Created: 2003-05-12Bibliographically approved
    5. On the origin of cis selectivity in the cyclization of N-protected 2-substituted 3-aza-5-hexenyl radicals: a density functional study
    Open this publication in new window or tab >>On the origin of cis selectivity in the cyclization of N-protected 2-substituted 3-aza-5-hexenyl radicals: a density functional study
    Show others...
    2004 (English)In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 69, no 5, p. 1487-1491Article in journal (Refereed) Published
    Abstract [en]

    Cyclization of the N-dimethylphosphinoyl-2-methyl-3-aza-5-hexenyl radical has been studied at the UB3LYP/6-31+G(d)//UB3LYP/6-31G(d) hybrid density functional level. The corresponding radical precursor has been synthesized and found to give cis/trans ratios of up to 10/1 in reductive radical cyclizations. The relative energies of reactant and transition state conformers were determined. In discord with the Beckwith-Houk model, it has been found that chair-axial transition states, which lead to cis products, are lowest in energy, rationalizing the observed experimental diastereoselectivity.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-90422 (URN)10.1021/jo030294h (DOI)14987001 (PubMedID)
    Available from: 2003-05-12 Created: 2003-05-12 Last updated: 2017-12-14Bibliographically approved
  • 139.
    Berlin, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Construction of Tetrahydrofuran-3-ones from Readily Available Organochalcogen Precursors via Radical Carbonylation/Reductive Cyclization2002In: Organic Letters, Vol. 4, p. 3-6Article in journal (Refereed)
  • 140.
    Berlin, Stefan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Radical Carbonylation/Reductive Cyclization for the Construction of Tetrahydrofuran-3-ones and Pyrrolidin3-0nesIn: Journal of Organic ChemistryArticle in journal (Refereed)
  • 141.
    Berlin, Stefan
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Engman, Lars
    A Radical Cyclization Route to Pyrrolidines Based on Conjugate Addition to Electron Deficient Phenylselenenylalkenes2000In: Tetrahedron Letters, Vol. 41, no 19, p. 3701-3704Article in journal (Refereed)
  • 142. Berlin, Stefan
    et al.
    Ericsson, Cecilia
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry, Organic Chemistry.
    Engman, Lars
    Construction of Tetrahydrofuran-3-ones from Readily Available Organochalcogen Precursors via Radical Carbonylation/Reductive Cyclization2002In: Organic Letters, Vol. 4, p. 3-Article in journal (Refereed)
  • 143. Berlin, Stefan
    et al.
    Ericsson, Cecilia
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry, Organic Chemistry.
    Engman, Lars
    Radical Carbonylation/Reductive Cyclization for the Construction of Tetrahydrofuran-3-ones and Pyrrolidin-3-ones2003In: Journal of Organic Chemistry, Vol. 68, p. 8386-Article in journal (Refereed)
  • 144. Bertilsson, S. K.
    et al.
    Ekegren, J. K.
    Modin, S. A.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Andersson, P. G.
    The aza-Diels-Alder reaction protocol - a useful approach to chiral, sterically constrained alpha-amino acid derivatives2001In: Tetrahedron, ISSN 0040-4020, Vol. 57, no 30, p. 6399-6406Article in journal (Refereed)
  • 145.
    Bertilsson, SK
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Andersson, PG
    A rigid dirhodium(II) carboxylate as an efficient catalyst for the asymmetric cyclopropanation of olefins2000In: JOURNAL OF ORGANOMETALLIC CHEMISTRY, ISSN 0022-328X, Vol. 603, no 1, p. 13-17Article in journal (Refereed)
    Abstract [en]

    The dirhodium(II) complex 7 of (1S,3R,4R)-2-(p-tert-butylphenylsulphonyl)-2-aza-bicycol[2.2.1]heptane-3-carboxylic acid (3) (or its enantiomer) was synthesised in four steps from cyclopentadiene, (R)- or (S)-phenylethylamine and methyl glyoxylate. Complex

  • 146.
    Bertilsson, SK
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Ekegren, JK
    Modin, SA
    Andersson, PG
    The aza-Diels-Alder reaction protocol - a useful approach to chiral, sterically constrained alpha-amino acid derivatives2001In: TETRAHEDRON, ISSN 0040-4020, Vol. 57, no 30, p. 6399-6406Article in journal (Refereed)
    Abstract [en]

    Different types of polycyclic alpha -amino acid derivatives are prepared from chiral imines by using well-established aza-Diels-Alder reaction conditions. Simply by varying the diene moiety, different products such as spirocyclic compounds 8 and 9, anthra

  • 147.
    Bertilsson, Sophie
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Asymmetric Formation and Isomerization of Three-Membered Rings: Catalyst Development and Evaluation2001Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Enantiopure α-amino acid derivatives were prepared using a protocol which allows for highly controlled regio- and chemoselectivity in the hydrogenation/ hydrogenolysis of aza-Diels-Alder adducts. One of the resulting α-amino esters, (1S,3R,4R)-2-azabicyclo[2.2.1]heptane-3-carboxylic acid ethyl ester, was utilized further as a catalyst precursor.

    Significant improvements were achieved in the asymmetric lithium amide-mediated epoxide rearrangement reaction. An efficient catalytic system was developed, based on 5 mol% of (1S,3R,4R)-3-(amino)methyl-2-azabicyclo[2.2.1]heptanes and stoichiometric amounts of lithium diisopropylamide (LDA). With pyrrolidine or (2R,5R)-dimethylpyrrolidine as the amine moiety, the isomerization into allylic alcohols was accomplished for 5–7-membered cycloalkene oxides and (Z)-octene oxide with yields of >90% and enantioselectivities up to 99% ee. The studies indicate that the active catalyst species is a monomer, which is in equilibrium with inactive aggregates. The addition of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) led to a reaction rate acceleration. In the catalytic reaction, where there is a competing LDA-mediated rearrangement, the presence of DBU also improved the enantioselectivity.

    Furthermore, the asymmetric addition of carbenes and nitrenes to olefins was investigated. N,N'- and N,O-oxazolines were evaluated as ligands in the Cu-catalyzed aziridination of alkenes. Two of the oxazolines formed highly active catalysts (90% yield). However, the enantioselectivity was moderate (≤34% ee). Another catalyst, tetrakis-[(1S,3R,4R)-2-(p-tert-butylbenzene)sulphonyl-2-azabicyclo[2.2.1]heptane-3-carboxylate]dirhodium(II) was prepared and successfully applied in the reaction of styrenes and cyclic enol ethers with phenyl- and vinyldiazoacetates, affording cyclopropanes in up to 95% yield and 92% ee. In contrast to earlier observations, the best results were obtained with electron-rich olefins.

  • 148.
    Bertilsson, Sophie
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Asymmetric base-promoted epoxide rearrangement: achiral lithium amides revisited2002In: Tetrahedron, no 58, p. 4665-4668Article in journal (Refereed)
  • 149.
    Bertilsson, Sophie
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Södergren, Mikael
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    New Catalysts for the Base-Promoted Isomerization of Epoxides to Allylic Alcohols. Broadened Scope and Near-Perfect Asymmetric Induction2002In: J. Org. Chem., no 67, p. 1567-1573Article in journal (Refereed)
  • 150.
    Bertilsson, Sophie
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Tedenborg, Lars
    Alonso, Diego
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Chiral N, N' - and N,O-Bidentate Anionic Ligands. Preparation, Metal Complexation, and Evalution in the Asymmetric Aziridination of Olefins1999In: Organometallics, no 18, p. 1281-1286Article in journal (Refereed)
1234567 101 - 150 of 1047
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