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  • 1.
    Ahlford, Katrin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zaitsev, Alexey B.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ekström, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    A Simple and Efficient Catalyst System for the Asymmetric Transfer Hydrogenation of Ketones2007Inngår i: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, nr 16, s. 2541-2544Artikkel i tidsskrift (Fagfellevurdert)
  • 2.
    Ali, Tara
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Structural Studies of O-Polysaccharides from Diarrhoeal Escherichia coli2007Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    This thesis describes the structural analysis of O-polysaccharides from the Gram-negative bacterium Escherichia coli that is a diarrhoeal pathogen. The Escherichia coli serotypes investigated were O178, O171, O166 and O128. The methods used in these studies were nuclear magnetic resonance spectroscopy and component analysis.

    All analysed serotypes had pentasaccharide repeating units. E. coli strain O128 and O166 was shown to have the topology of four carbohydrate residues in the backbone while the 5-residue backbone is found in E. coli O178 and O171.

    The biological repeating units have been determined for the analysed polysaccharides and it was shown that all of the serotypes studied had a 3-substituted N-acetylgalactosamine residue at the reducing end. From this it was deduced that the terminal end of E. coli O171 and O128 have sialic acid and blood type antigens, respectively. This should make E. coli O171 and O128 less recognizable to the immune system as a foreign invader. This can result in that E. coli O171 and O128 may evade the immune system more easily.

  • 3.
    Ali, Tara
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Weintraub, Andrej
    Widmalm, Göran
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Structural determination of the O-antigenic polysaccharide from Escherichia coli O1662007Inngår i: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 342, nr 2, s. 274-278Artikkel i tidsskrift (Fagfellevurdert)
  • 4.
    Andersson, M.
    et al.
    YKI Institute for Surface Chemistry, Box 5607, SE-114 86 Stockholm, Sweden.
    Hillerström, A.
    YKI Institute for Surface Chemistry, Box 5607, SE-114 86 Stockholm, Sweden.
    Svensk, A.
    YKI Institute for Surface Chemistry, Box 5607, SE-114 86 Stockholm, Sweden.
    Younesi, S. R.
    YKI Institute for Surface Chemistry, Box 5607, SE-114 86 Stockholm, Sweden.
    Sjöström, E.
    Blute, I.
    Kjellin, M.
    Kizilng, J.
    Kronberg, B.
    Oldgren, J.
    Hansson, A.
    Sjöstrand, S.
    A New Class of Labile Surfactants that Break Down to Non-surface Active Products upon Heating or after a Pre-set Time, without the Need for a pH Change2007Inngår i: Tenside Surfactants Detergents, ISSN 0932-3414, E-ISSN 2195-8564, Vol. 44, nr 6, s. 366-372Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new class of labile surfactants that break down at a controllable rate without the need for a change in pH will be presented. The invention has been patented by YKI Institute for Surface Chemistry, and is based on use of β-keto acids or their salts as surface-active compounds. These surfactants spontaneously break down through decarboxylation, to form an oil-like ketone and CO 2/HCO 3 -/CO 32 - depending on pH. The rate of breakdown can be controlled within a wide range by temperature or by certain additives, but, unlike most cleavable surfactants, a change in pH is not needed. Furthermore the surfactants can be conveniently activated from a stabile precursor just before use, and one (of many possible) precursors of this kind is already available on the industrial scale in the form of a wellknown chemical that is FDA-approved in other, non-surfactant, applications. The compound in question, alkyl ketene dimer (AKD), is produced in large scale by a number of large chemical producers today, and used for hydrophobization of paper. The present article gives an overview of the surfactant chemistry, with focus on recent studies of the kinetics of activation of the surfactant precursor and breakdown kinetics of the labile surfactant at different conditions. Furthermore, possible industrial applications of the surfactant will be discussed, with one example taken from a recent feasibility study performed within the car washing area. © Carl Hanser Publisher.

  • 5.
    Andersson, Nina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Mesostructured materials: Synthesis towards applications2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    A new class of materials with well-defined structures on mesoscopic (2-50 nm) length scales has attracted considerable interest during the last decade. These mesostructured mataterials are formed from the self-assembly of amphiphillic molecules and inorganic precursors. The aim of this thesis has been to develop preparation methods that are scalable, and at the same time allow for efficient structural control coupled with possibility to incorporate different functionalities.

    Two different industrial processes for production of particles with spherical morphology were successfully tailored for synthesis of well-ordered mesostructured particles. An existing spray drying method for a fast and continuous production was further developed, and for the first time, an emulsion-based method was implemented. The latter method resulted in superior control of both particle size and internal mesostructure.

    Mesostructured photochromic pigments were synthesised by incorporating photochromic dyes in the organic domains of the surfactant templated inorganic/organic mesostructured silica particles. The pigments were produced using a one-pot synthesis method employing an aerosol reactor, allowing control over both the internal mesostructure and the dye content. We show that transparent photochromic films can be prepared using latex binders and conventional coating technology.

    Mesoporous magnetic carrier materials were prepared by adding iron oxide nanoparticles during either the emulsion- or aerosol processing. The surfactant templated silica matrix displayed well-ordered internal pore architecture with limited pore blocking caused by the incorporated iron oxide nanoparticles. The iron oxide content was precisely controlled, and the magnetic properties were preserved during the processing. Finally we demonstrate that these materials can be used to magnetically separate water-soluble dyes from solution.

  • 6. Back, Marcus
    et al.
    Nyhlén, Jonas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kvarnström, Ingemar
    Rosenquist, Åsa
    Samuelsson, Bertil
    Design, synthesis and SAR of potent statin-based β-secretase inhibitors: Exploration of P1 phenoxy and benzyloxy residues2007Konferansepaper (Annet vitenskapelig)
  • 7.
    Baltzer, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi, Organisk kemi II.
    Polypeptide Conjugate Binders for Protein Recognition2007Inngår i: Topics in current chemistry, ISSN 0340-1022, E-ISSN 1436-5049, Vol. 277, s. 89-106Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    A new class of hybrid molecules for protein recognition is presented, where polypeptides are covalently linked to small organic molecules to form polypeptide conjugates that bind proteins with high affinity and selectivity. To illustrate the concept, a binder for human carbonic anhydrase 11 with a dissociation constant of 4 nM is described. The affinity of the polypeptide conjugate arises from cooperativity in binding between a benzenesulfonamide residue, with a dissociation constant of 1.5 mu M, and the polypeptide scaffold with a dissociation constant of < 1 mM. The combination of a ligand with moderate affinity for a target protein with a polypeptide relaxes considerably the need for high affinity on the part of the polypeptide, and thus the need for structural complexity and preorganization. At the same time, the requirement for high affinity on the part of ligand is relaxed. As a consequence, the time for development of robust, high affinity, selective binder is shortened. The chemical approach to protein recognition provides well-defined molecular entities that are conveniently handled, stored and site-specifically functionalized.

  • 8.
    Barman, Jharna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Targeting RNA by the Antisense Approach and a Close Look at RNA Cleavage Reaction2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis summarizes the results of studies on two aspects of nucleic acids. Chemically modified antisense oligonucleotides (AONs) have been evaluated with regards to their suitability for mRNA targeting in an antisense approach (Paper I – III). The chemically modified nucleotidic units 2'-O-Me-T, 2'-O-MOE-T, oxetane-T, LNA-T, azetidine-T, aza-ENA-T, carbocyclic-ENA-T and carbocyclic-LNA-T were incorporated into 15-mer AONs and targeted against a 15-mer RNA chosen from the coding region of SV-40 large T antigen. The comparative study showed that a single modified nucleotide in the AON with North-East locked sugar (oxetane-T and azetidine-T) lowered the affinity for the complementary RNA whereas North locked sugars (LNA-T, aza-ENA-T, carbocyclic-ENA-T, and carbocyclic-LNA-T) significantly improved the affinity. A comparative RNase H digestion study showed that modifications of the same type (North-East type or North type) in different sequences gave rise to similar cleavage patterns. Determination of the Michaelis-Menten parameters by kinetic experiments showed that the modified AONs recruit RNase H resulting in enhanced turnover numbers (kcat) although with weaker enzyme-substrate binding (1/Km) compared to the unmodified AON. The modified AONs were also evaluated with regards to resistance towards snake venom phosphodiesterase and human serum to estimate their stability toward exonucleases. The aza-ENA-T and carbocyclic-ENA-T modified AONs showed improved stability compared to all other modified AONs. In general, the modified AONs with North type nucleotides (except LNA-T) were found to be superior to the North-East type as they showed improved target affinity, comparable RNase H recruitment capability and improved exonuclease stability.

    The second aspect studied in this thesis is based on physicochemical studies of short RNA molecules utilizing NMR based pH titration and alkaline hydrolysis reactions (Paper IV – V). The NMR based (1H and 31P) pH titration studies revealed the effect of guaninyl ion formation, propagated electrostatically through a single stranded chain in a sequence dependent manner. The non-identical electronic character of the internucleotidic phosphodiesters was further verified by alkaline hydrolysis experiments. The internucleotidic phosphodiesters, which were influenced by guaninyl ion formation, were hydrolyzed at a faster rate than those sequences where such guaninyl ion formation was prevented by replacing G with N1-Me-G.

  • 9.
    Bergqvist, Per-Anders
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Zaliauskiene, Audrone
    Field study considerations in the use of passive sampling devices in water monitoring2007Inngår i: Passive Sampling Techniques in Environmental Monitoring / [ed] R. Greenwood, G. Mills and B. Vrana, Amsterdam: Elsevier, 2007, s. 311-328Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Semipermeable membrane devices (SPMDs) are passive monitors that are being increasingly used by monitoring agencies and wastewater dischargers to measure the contents of lipophilic organic chemicals that may adversely affect water quality. This chapter addresses the most frequently asked questions regarding the use of SPMDs for water monitoring and other questions related to the field application of SPMDs. It provides a sound understanding of the applicability and limitations of SPMDs for obtaining reliable monitoring data. The chapter discusses under field study considerations: pre-exposure considerations; SPMD storage considerations; and precautions/procedures during deployment and retrieval of SPMDs. In environmental monitoring projects using SPMDs, quality control (QC) procedures for sampling and analysis are applied to ensure that the data are of high quality. Appropriate QC samples are prepared to quantify possible sampler contamination during transport, deployment, retrieval, storage, processing, enrichment, fractionation operations and analyte recovery. In general, two groups of quality assurance measures are implemented: replicate QC and sampling device control.

  • 10.
    Bielawski, Marcin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Olofsson, Berit
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    High-Yielding One-Pot Synthesis of Diaryliodonium Triflates from Arenes and Iodine or Aryl Iodides2007Inngår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, nr 24, s. 2521-2523Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Unsymmetric and symmetric diaryliodonium triflates are synthesized from both electron-deficient and electron-rich substrates in a fast, high yielding, and operationally simple protocol employing arenes and aryl iodides or iodine.

  • 11.
    Bielawski, Marcin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhu, Mingzhao
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Olofsson, Berit
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Efficient and General One-Pot Synthesis of Diaryliodonium Triflates: Optimization, Scope and Limitations2007Inngår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 349, nr 17-18, s. 2610-2618Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Symmetrical and unsymmetrical diaryliodonium triflates have been synthesized from both electron-deficient and electron-rich arenes and aryl iodides with mCPBA and triflic acid. A thorough investigation of the optimization, scope and limitations has resulted in an improved one-pot protocol that is fast, high-yielding, and operationally simple. The reaction has been extended to the direct synthesis of symmetrical iodonium salts from iodine and arenes, conveniently circumventing the need for aryl iodides.

  • 12.
    Bielawski, Marcin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhu, Mingzhao
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Olofsson, Berit
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Efficient and general one-pot synthesis of diaryliodonium triflates: scope and limitations2007Inngår i: SIS Report: The 10th Symposium on Iodine Science, Chiba University, Japan 2007, 2007, s. 19-22Konferansepaper (Annet vitenskapelig)
  • 13.
    Blid, Jan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Panknin, Olaf
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Tuzina, Pavel
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Somfai, Peter
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Lewis acid mediated asymmetric 2,3 -sigmatropic rearrangement of allylic amines. Scope and mechanistic investigation2007Inngår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 72, nr 4, s. 1294-1300Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    [GRAPHIC] The first asymmetric [2,3]-sigmatropic rearrangement of achiral allylic amines has been realized by quaternization of the amines with an enantiomerically pure diazaborolidine and subsequent treatment with Et3N. The resultant homoallylic amines were obtained in good yields and excellent ee's. The observed diastereo- and enantioselectivities were rationalized by invoking a kinetically controlled process, and support for this model was obtained from an NMR spectroscopic investigation of the chiral Lewis acid-substrate complex. The structure of the Lewis acid-product complex was established by X-ray crystallographic analysis and supported the proposed mechanism.

  • 14.
    Blomberg, David
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Synthesis of β-turn and pyridine based peptidomimetics2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Despite the unfavorable pharmacokinetic properties associated with peptides, they are still of great interest in drug development due to a multitude of interesting biological functions. The development of peptidomimetics strives to maintain or improve the biological activity of a peptide concurrently with removing the unwanted properties. This thesis describes two synthetic approaches to peptidomimetics with particular emphasis on secondary structure mimetics.

    First the design, synthesis and evaluation of two beta-turn mimetics incorporated in the endorphin Leu-enkephalin is presented. The beta-turn mimetics were stabilized by replacement of the intramolecular hydrogen bond with an ethylene bridge, and the amide bond between Tyr and Gly was replaced with an ether linkage. Linear analogues of the two mimetics were also synthesized. The peptidomimetics and their linear analogues were evaluated in a competitive binding assay at two opiate receptors, my and delta. One of the cyclized beta-turn mimetics was found to be a delta receptor antagonist with an IC50 value of 160 nM.

    Second a synthetic strategy to a beta-strand mimetic using 2-fluoro-4-iodopyridine as scaffold is described. The synthesis involved a Grignard exchange reaction on the pyridine scaffold using an amino acid derivative as electrophile followed by an SNAr reaction using an amine as nucleophile. The synthesis of a tripeptidomimetic of Leu-Gly-Gly and attempts to introduce chiral building blocks at the C-terminal, as well as studies towards elongated mimetics are presented.

    Two additional studies deal with the synthesis of two classes of potential thrombin inhibitors based on the pyridine scaffold. The first class contain pyridine as central fragment (P2 residue) substituted with a para-amidinobenzylamine group as P1 residue and various benzoyl groups as P3 residues. Three potential thrombin inhibitors were synthesized and found to be microM inhibitors in an enzymatic assay. In the second class, the pyridine ring serves as P3 residue. This class also lacks a strongly basic group in the P1 position. A small library of eight compounds were synthesized and evaluated in the enzymatic assay. Unfortunately, these compounds lacked inhibitory activity.

  • 15.
    Bogár, Krisztián
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthetic Transformations via Metal- and Enzyme-Catalyzed Dynamic Kinetic Resolution2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis deals with the preparation of a new half-sandwich type ruthenium(II)- catalyst for racemization of optically active secondary alcohols and the development of a highly efficient method in combination with lipases such as Candida antarctica lipase B and Pseudomonas cepacia lipase for dynamic kinetic resolution of various functionalized alcohols under mild reaction conditions.

    It was shown that the RuCl(CO)25-C5Ph5) complex can racemize optically active aliphatic and aromatic secondary alcohols at room temperature in rather short times. Different parameters, such as the nature of the catalyst, catalyst loading and solvent effect were studied. After the optimization steps, the Ru-catalyzed racemization of (S)-1-phenylethanol in the presence of Candida antarctica lipase B was also investigated. The compatibility of the metal- and enzyme-catalyzed reactions led to a highly efficient coupled catalytic system for transformation of racemic alcohols to their enantiomerically pure acetates. This protocol was applied for a wide range of secondary alcohols. It was shown that in the case of allylic alcohols the obtained enantiopure allylic acetates are useful compounds for synthesis of α-methyl carboxylic acids such as (R)-Flurbiprofen and acyloin acetates. Highly selective dynamic kinetic asymmetric transformation of 3,5-piperidine diol to deliver various 3,5-dioxygenated piperidines is also described.

  • 16.
    Bogár, Krisztián
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    High-yielding metalloenzymatic dynamic kinetic resolution of fluorinated aryl alcohols2007Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 48, nr 31, s. 5471-5474Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dynamic kinetic resolution (DKR) of various fluorinated aryl alcohols by a combination of lipase-catalyzed enzymatic resolution with in situ ruthenium-catalyzed alcohol racemization is described. (R)-Selective Candida antarctica lipase B (CALB) was employed for transesterification of different fluoroaryl alcohols in DKR reactions delivering the corresponding acetates in high yield (97%) with excellent enantiomeric excess (98%).

  • 17.
    Bogár, Krisztián
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Hoyos Vidal, Pilar
    Alcántara León, Andrés R.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Chemoenzymatic Dynamic Kinetic Resolution of Allylic Alcohols: A Highly Enantioselective Route to Acyloin Acetates2007Inngår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 9, nr 17, s. 3401-3404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dynamic kinetic resolution (DKR) of a series of sterically hindered allylic alcohols has been conducted with Candida antarctica lipase B (CALB) and ruthenium catalyst 1. The optically pure allylic acetates obtained were subjected to oxidative cleavage to give the corresponding acylated acyloins in high yields without loss of chiral information.

  • 18. Bogár, Krisztián
    et al.
    Martín-Matute, Belén
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Large-scale ruthenium- and enzyme-catalyzed dynamic kinetic resolution of (rac)-1-phenylethanol2007Inngår i: Beilstein Journal of Organic Chemistry, ISSN 1860-5397, Vol. 3, s. artikel nr 50-Artikkel i tidsskrift (Fagfellevurdert)
  • 19.
    Borg, Tessie
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Restorp, Per
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Somfai, Peter
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    ORGN 988-Diastereoselective addition of nucleophiles to aldehydes having polar - and -substituents2007Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 234Artikkel i tidsskrift (Annet vitenskapelig)
  • 20. Carballeira, José Daniel
    et al.
    Krumlinde, Patrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bocola, Marco
    Vogel, Andreas
    Reetz, Manfred T.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Directed evolution and axial chirality: optimization of the enantioselectivity of Pseudomonas aeruginosa lipase towards the kinetic resolution of a racemic allene2007Inngår i: Chemical Communications, ISSN 1359-7345, Vol. 20, s. 1913-1915Artikkel i tidsskrift (Fagfellevurdert)
  • 21.
    Carlsson, Marcus
    Umeå universitet, Teknisk-naturvetenskaplig fakultet, Kemi.
    Synthesis and optical characterization of optical power limiting platinum(II) acetylides2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Interactions between light and a molecule can result in reversible or irreversible changes in properties of both the light and the molecule. Of the many known interactions, nonlinear absorption is a process in which an intense light signal, for instance from a laser, can be moderated. This can be manifested either in a marked lowering of the light’s intensity or in reductions in fluctuations of its intensity. Such an effect is often termed ‘optical power limiting’ (OPL).

    High power lasers can be very dangerous since their high intensity can damage or destroy eyes and optical sensors. However, there are currently no adequate protective measures against lasers that cover the entire visible region and there is an increasing demand for new or improved OPL materials. Some of the most promising optical power limiting materials are substances that combine nonlinear optical properties with high transparency in normal light, but after activation by a laser beam, their light transmittance falls extremely rapidly via so-called self-activating mechanisms. The platinum(II) acetylides comprise one class of compounds with such properties.

    In this study, various OPL Pt(II) acetylides were synthesized and their nonlinear optical properties were characterized. The emphasis of the work was on preparation of the compounds, but in order to design organoplatinum chromophores for OPL, attempts were also made to obtain insight into the mechanisms of nonlinear absorption.

    The work was divided into two main parts. In the first the goal was to find compounds that are good optical limiters in solution. The possibility of isolating the chromophore site by dendron shielding and the effects of incorporating a thiophene ring into the organic molecular system were also explored. In addition, a new route for synthesizing these compounds was developed. The second part was focused on incorporating the most interesting compounds into solid materials. The preparation and characterization of Pt(II) acetylides with molecular groups for covalent attachment to a silica matrix via the solution gel approach is described.

  • 22.
    Chatterjee, Subhrangsu
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Physicochemical and Structural Aspects of Nucleic Acids2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis consists of seven research publications concerning (i) pKa studies of nucleobases in model nucleotides to understand why RNA duplexes are more stable than DNA duplexes (Paper I), (ii) the role of Me(T)-π interactions in the relative stability of DNA-RNA heteroduplexes (Paper II), (iii) pKa measurements in nucleotides with different 2′-substituents (paper III), (iv) a conformation study of constrained sugars and a pKa study of 1-thyminyl to reveal effect of sugar constraints on the pKa of the nucleobase (paper IV), (v) NMR and MD studies of 1′, 2′-oxetane constrained thymidine incorporated Dickerson Drew dodecamer (paper V), (vi) the sequence dependent pKa perturbation of 9-guaninyl moeity in single stranded (ss) DNA and RNA (paper VI), (vii) the non identical chemical nature of internucleotidic phosphates in (ss) RNA using 31P NMR (paper VI), and an alkaline hydrolysis study of phosphodiesters in ssRNAs (paper VII). The architecture of DNA and RNA molecules is determined by (a) hydrogen bonding (b) base stacking (c) a variety of additional non-covalent interactions. In paper (I) we showed that A-U and G-C base pairings in RNA are more stable than A-T and G-C base pairings in DNA by 4.3 and 1 kJ mol-1 respectively. Me(T)-π interaction plays a dominant role in the relative stability of DNA-RNA duplexes (paper II). In paper III and IV, we have shown that 1′ , 2′- oxetane and azetidine rings have strong inductive effect on pyrimidine bases, and that the H2′-sugar proton can be the marker to understand the pseudoaromaticity of pyrimidine bases, as well as increasing constraints in sugar reducing the basicity of nucleobases. A 1′, 2′-oxetane locked thymidine (T) moiety deforms the local structure of Dickerson-Drew dodecamer, d(CGCGAATTCGCG)2- investigated by High resolution NMR and MD study, as is discussed in the paper V. In papers VI and VII, we showed sequence context dependent pKa (N1) of 9-guaninyl perturbation in (ss) DNAs and RNAs and the non identical chemical nature of inter-nucleotidic phosphate groups in single stranded RNAs.

  • 23.
    Dong, Hai
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Pei, Zhichao
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Angelin, Marcus
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Byström, Styrbjörn
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Ramström, Olof
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Efficient Synthesis of β-D-Mannosides and β-D-Talosides by Double Parallel or Double Serial Inversion2007Inngår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 72, nr 10, s. 3694-3701Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A neighboring equatorial ester group plays a highly important role in the Lattrell-Dax (nitrite-mediated) carbohydrate epimerization reaction, inducing the formation of inversion compounds in good yields. On the basis of this effect, efficient synthetic routes to beta-D-mannosides and beta-D-talosides, from the corresponding beta-D-galactosides and beta-D-glucosides, have been designed. The present routes are based on multiple regioselective acylation via the respective stannylene intermediates, followed by inversions to the corresponding manno- and talopyranoside structures by nitrite or acetate substitution. It was found that the ester group was able to induce the inversion of its two neighboring groups in high yields following either a double parallel or a double serial inversion process. By combination of direct inversion, and neighboring- as well as remote-group participation, several beta-D-mannoside and beta-D-taloside derivatives were very conveniently obtained in good yields.

  • 24.
    Dong, Hai
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Pei, Zhichao
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Byström, Styrbjörn
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Ramström, Olof
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Reagent-dependent regioselective control in multiple carbohydrate esterifications2007Inngår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 72, nr 4, s. 1499-1502Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Regioselective control in organotin-mediated multiple acylation of carbohydrates is presented. The acylation reagent could be efficiently used to direct the product formation. Reagent-dependent thermodynamic and kinetic control and dynamic assistance mechanisms are suggested, resulting in the efficient preparation of building blocks that normally require many steps with traditional synthesis.

  • 25.
    Ekström, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Transition Metal Hydrides: Biomimetic Studies and Catalytic Applications2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In this thesis, studies of the nature of different transition metal-hydride complexes are described. The first part deals with the enantioswitchable behaviour of rhodium complexes derived from amino acids, applied in asymmetric transfer hydrogenation of ketones. We found that the use of amino acid thio amide ligands resulted in the formation of the R-configured product, whereas the use of the corresponding hydroxamic acid- or hydrazide ligands selectively gave the S-alcohol.

    Structure/activity investigations revealed that the stereochemical outcome of the catalytic reaction depends on the ligand mode of coordination.

    In the second part, an Fe hydrogenase active site model complex with a labile amine ligand has been synthesized and studied. The aim of this study was to find a complex that efficiently catalyzes the reduction of protons to molecular hydrogen under mild conditions. We found that the amine ligand functions as a mimic of the loosely bound ligand which is part of the active site in the hydrogenase.

    Further, an Fe hydrogenase active site model complex has been coupled to a photosensitizer with the aim of achieving light induced hydrogen production. The redox properties of the produced complex are such that no electron transfer from the photosensitizer part to the Fe moiety occurs.

    In the last part of this thesis, the development of a protocol for the transfer hydrogenation of ketones to secondary alcohols without the involvement of transition metal catalysts is described. A variety of ketones were efficiently reduced in 2-propanol using catalytic amounts of alkali alkoxide under microwave irradiation.

  • 26.
    Ekström, Jesper
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Wettergren, Jenny
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Adolfsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    A Simple and Efficient Catalytic Method for the Reduction of Ketones2007Inngår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 349, nr 10, s. 1609-1613Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A range of ketones was efficiently reduced in the presence of catalytic amounts of lithium isopropoxide in 2-propanol under microwave heating, with alcohol products being formed in yields up to 99 %.

  • 27.
    Frigell, Jens
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Cumpstey, Ian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    First synthesis of 4a-carba-beta-D-galactofuranose2007Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 48, nr 52, s. 9073-9076Artikkel i tidsskrift (Fagfellevurdert)
  • 28.
    Frölander, Anders
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Impact of Secondary Interactions in Asymmetric Catalysis2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis deals with secondary interactions in asymmetric catalysis and their impact on the outcome of catalytic reactions.

    The first part revolves around the metal-catalyzed asymmetric allylic alkylation reaction and how interactions within the catalyst affect the stereochemistry. An OH–Pd hydrogen bond in Pd(0)–π-olefin complexes of hydroxy-containing oxazoline ligands was identified by density functional theory computations and helped to rationalize the contrasting results obtained employing hydroxy- and methoxy-containing ligands in the catalytic reaction. This type of hydrogen bond was further studied in phenanthroline metal complexes. As expected for a hydrogen bond, the strength of the bond was found to increase with increased electron density at the metal and with increased acidity of the hydroxy protons.

    The second part deals with the use of hydroxy- and methoxy-containing phosphinooxazoline ligands in the rhodium- and iridium-catalyzed asymmetric hydrosilylation reaction. The enantioselectivities obtained were profoundly enhanced upon the addition of silver salts. This phenomenon was explained by an oxygen–metal coordination in the catalytic complexes, which was confirmed by NMR studies of an iridium complex. Interestingly, the rhodium and iridium catalysts nearly serve as pseudo-enantiomers giving products with different absolute configurations.

    The final part deals with ditopic pyridinobisoxazoline ligands and the application of their metal complexes in asymmetric cyanation reactions. Upon complexation, these ligands provide catalysts with both Lewis acidic and Lewis basic sites, capable of activating both the substrate and the cyanation reagent. Lanthanide and aluminum complexes of these ligands were found to catalyze the addition of the fairly unreactive cyanation reagents ethyl cyanoformate and acetyl cyanide to benzaldehyde, whereas complexes of ligands lacking the Lewis basic coordination sites failed to do so.

  • 29.
    Frölander, Anders
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Moberg, Christina
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Ag+-Assisted Hydrosilylation: Complementary Behavior of Rh and Ir Catalysts (Reversal of Enantioselectivity)2007Inngår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 9, nr 7, s. 1371-1374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The presence of a suitably situated hydroxy function in a PHOX ligand leads to an enhancement of the enantioselectivity in Rh-catalyzed hydrosilylations of prochiral ketones in the presence of AgBF4 (95% ee for acetophenone as compared to 75% using i-Pr-phosphinooxazoline (PHOX)). Exchanging Rh for Ir affords the product with the opposite absolute configuration (78% ee).

  • 30.
    Hagberg, Daniel
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Synthesis of Organic Chromophores for Dye Sensitized Solar Cells2007Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis is divided into four parts with organic chromophores for dye sensitized solar cells as the common feature and an introduction with general concepts of the dye sensitized solar cells.

    The first part of the thesis describes the development of an efficient organic chromophore for dye sensitized solar cells. The chromophore consists of a triphenylamine moiety as an electron donor, a conjugated linker with a thiophene moiety and cyanoacrylic acid as an electron acceptor and anchoring group. During this work a strategy to obtain an efficient sensitizer was developed. Alternating the donor, linker or acceptor moieties independently, would give us the tool to tune the HOMO and LUMO energy levels of the chromophores. The following parts of this thesis regard this development strategy.

    The second part describes the contributions to the HOMO and LUMO energy levels when alternating the linker moiety. By varying the linker the HOMO and LUMO energy levels was indeed shifted. Unexpected effects of the solar cell performances when increasing the linker length were revealed, however.

    The third part describes the investigation of an alternative acceptor group, rhodanine-3-acetic acid, in combination with different linker lengths. The HOMO and LUMO energy level tuning was once again successfully shifted. The poor electronic coupling of the acceptor group to the semiconductor surface proved to be a problem for the overall efficiency of the solar cell, however.

    The fourth part describes the contributions from different donor groups to the HOMO and LUMO energy levels and has so far been the most successful in terms of reaching high efficiencies in the solar cell. A top overall efficiency of 7.1 % was achieved.

  • 31.
    Hamberg, Anders
    et al.
    KTH, Skolan för bioteknologi (BIO), Biokemi.
    Lundgren, Stina
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Wingstrand, Erica
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Moberg, Christina
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Hult, Karl
    KTH, Skolan för bioteknologi (BIO), Biokemi.
    High Throughput Synthesis and Analysis of Acylated Cyanohydrins2007Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 13, nr 15, s. 4334-4341Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The yields and optical purities of products obtained from chiral Lewis acid/Lewis base-catalysed additions of alpha-ketonitriles to prochiral aldehydes could be accurately determined by an enzymatic method. The amount of remaining aldehyde was determined after its reduction to an alcohol, whilst the two product enantiomers were analysed after subsequent hydrolysis first by the (S)-selective Candida antarctica lipase B and then by the unselective pig liver esterase. The method could be used for analysis of products obtained from a number of aromatic aldehydes and aliphatic ketonitriles. Microreactor technology was successfully combined with high-throughput analysis for efficient catalyst optimization.

  • 32.
    Hartikka, Antti
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Towards Rational Design of Asymmetric Catalyst for Organometallic and Organocatalytic Reactions2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis deals with synthetically modified chiral molecules and their application in asymmetric catalysis. The first part of the thesis describes the use of commercially available chiral diamine ligands in the iridium catalyzed transfer hydrogenation of aromatic ketones. The chiral diamine ligands were mixed with an appropriate transition-metal complex, which after addition of suitable base provided a chiral transition metal complex capable of reducing a range of different aromatic ketones in high yields and enantioselectivities. The developed methodology constitutes a cost effective and readily available procedure for transfer hydrogenation reactions. The following chapters in the thesis are completely devoted to rational design of small organic molecules acting as catalyst in various organocatalytic transformations. Organocatalytic methodology, represent a new and complementary approach to asymmetric organic synthesis, as compared to e.g. transition metal based methodology. Advantages of this methodology typically include mild and less stringent reaction conditions. This, in combination with the lack of toxic transition metal by-products, makes the process more environmentally benign; the organocatalytic methodology, therefore represent a promising approach towards implementation of green chemistry in organic synthesis. Despite this promise, typical drawbacks of the current methodology are long reaction times and the need for high catalyst loadings. Thus, a large demand exists for enhancing reactivity and increasing selectivity in organocatalytic reactions. The present thesis describes several efforts where we have tried to rationally design improved catalysts for various enantioselective organocata-lytic reactions. First, a structurally modified L-proline, incorporating a 1H-tetrazolic acid, was synthesized and evaluated in the direct asymmetric organocatalytic aldol reaction. As shown in Paper II, the catalyst displayed very high reactivity and subsequent studies were initiated in order to rationalize the reactivity enhancement (Paper III). Delightfully, the design principle of a 1H-tetrazolic acid as replacement for a carboxylic acid has since been widely used in the community, including our own efforts in organocatalytic asymmetric cyclopropanations (Paper V)and Diels-Alder reactions (Paper VII). Novel catalysts, including other functionalizations, were also designed for organocatalytic asymmetric addition of nitroalkanes to α,β-unsaturated aldehydes (Paper IV) and for cyclopropanations (Paper VI).

  • 33.
    Hasimbegovic, Vedran
    et al.
    Unit for Organic Chemistry, Department of Biosciences and Nutrition, Karolinska Institute, Novum Research Park.
    Slätt, Johnny
    Unit for Organic Chemistry, Department of Biosciences and Nutrition, Karolinska Institute, Novum Research Park.
    Bergman, Jan
    Unit for Organic Chemistry, Department of Biosciences and Nutrition, Karolinska Institute, Novum Research Park.
    Janosik, Tomasz
    Unit for Organic Chemistry, Department of Biosciences and Nutrition, Karolinska Institute, Novum Research Park.
    The synthesis of some 3-acylindoles revisited2007Inngår i: Journal of Heterocyclic Chemistry, ISSN 0022-152X, E-ISSN 1943-5193, Vol. 44, nr 5, s. 1213-1217Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A study probing the scope of acylation of indoles with dicarboxylic acids in acetic anhydride has beenperformed, resulting in products incorporating 3-acylindole- or 1-acylindole motifs depending on thechoice of the acid reactant. Synthetically useful results were only obtained from reactions involvingmalonic acid or Meldrum’s acid. Correlations to previous studies have also been made and discussed.

  • 34.
    Haugaard-Kedström (published under the name Haugaard-Jönsson), Linda M.
    et al.
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Hossain, Akther
    Daly, Norelle
    Bathgate, Ross
    Craik, David
    Wade, John
    Rosengren, Johan
    Högskolan i Kalmar, Naturvetenskapliga institutionen.
    Structural characterization of a H3-INSL5 relaxin peptide chimera2007Inngår i: Proceedings of the 4th International Peptide Symposium / [ed] Wilce, Jackie, Cairns, Australia, 2007Konferansepaper (Fagfellevurdert)
  • 35. Holmgren, Arne
    et al.
    Lu, Jun
    Vlamis-Gardikas, Alexios
    Zhao, Rong
    Kandasamy, Karuppasamy
    Engman, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi, Organisk kemi I.
    Hoffner, Sven
    Bacterial Thioredoxin Reductase Inhibitors and Methods for Use Thereof2007Patent (Annet (populærvitenskap, debatt, mm))
  • 36.
    Ibrahem, Ismail
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Development of organocatalytic asymmetric transformations2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The ability of amino acids and amino acid derivatives to mediate various organocatalytic asymmetric transformations has been investigated and applied in the development of various reactions. This work describes the development of a direct catalytic asymmetric α-aminomethylation of ketones and aldehydes, a catalytic asymmetric aziridination, hydrophosphination and amination of α,β-unsaturated aldehydes.

  • 37.
    Ibrahem, Ismail
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rios, Ramon
    Vesely, Jan
    Hammar, Peter
    Eriksson, Lars
    Himo, Fahmi
    Cordova, Armando
    Enantioselective Organocatalytic Hydrophosphination of α,β- Unsaturated Aldehydes2007Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 46, s. 4507-Artikkel i tidsskrift (Fagfellevurdert)
  • 38.
    Ibrahem, Ismail
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rios, Ramon
    Vesely, Jan
    Zhao, Guiling
    Cordova, Armando
    Organocatalytic Asymmetric 5-Hydroxyisoxazolidine Synthesis: A Highly Enantioselective Route to β-Amino Acids2007Inngår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, s. 849-852Artikkel i tidsskrift (Fagfellevurdert)
  • 39.
    Ibrahem, Ismail
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Rios, Ramón
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Vesely, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Hammar, Peter
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Himo, Fahmi
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Enantioselective organocatalytic hydrophosphination of alpha,beta-unsaturated aldehydes2007Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 46, s. 4507-4510Artikkel i tidsskrift (Fagfellevurdert)
  • 40.
    Ibrahem, Ismail
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zhao, Guiling
    Cordova, Armando
    Direct Catalytic Enantioselective α-Aminomethylation of Aldehydes2007Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 13, s. 683-Artikkel i tidsskrift (Fagfellevurdert)
  • 41.
    Kauppi, Anna M.
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Andersson, David C.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Norberg, Henrik A.
    Innate Pharmaceuticals AB, Umestan Företagspark, SE-90347 Umeå, Sweden.
    Sundin, Charlotta
    Innate Pharmaceuticals AB, Umestan Företagspark, SE-90347 Umeå, Sweden.
    Linusson Jonsson, Anna
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Elofsson, Mikael
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Kemiska institutionen.
    Inhibitors of type III secretion in Yersinia: design, synthesis and multivariate QSAR of 2-sulfonamino-benzanilides2007Inngår i: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, E-ISSN 1464-3391, Vol. 15, nr 22, s. 6994-7011Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Compound 1, 2-(benzo[1,2,5]thiadiazole-4-sulfonylamino)-5-chloro-N-(3,4-dichloro-phenyl)-benzamide, was identified as a putative type III secretion inhibitor in Yersinia, and the compound thus has a potential to be used to prevent or treat bacterial infections. A set of seven analogues was synthesized and evaluated in a type III secretion dependent reporter-gene assay with viable bacterial to give basic SAR. A second set of 19 compounds was obtained by statistical molecular design in the building block and product space and subsequent synthesis. Evaluation in the reporter-gene assay showed that the compounds ranged from non-active to compounds more potent than 1. Based on the data multivariate QSAR models were established and the final Hi-PLS model showed good correlation between experimentally determined % inhibition and the calculated % inhibition of the reporter-gene signal.

  • 42.
    Lundgren, Stina
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Efficient Synthesis and Analysis of Chiral Cyanohydrins2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis deals with the development of new methods for efficient synthesis and analysis in asymmetric catalysis. It focuses on the preparation of chiral cyanohydrins by enantioselective addition of cyanide to prochiral aldehydes.

    The initial part of the thesis describes the development of a dual Lewis acid– Lewis base activation system for efficient synthesis of chiral O-acylated and Ocarbonylated cyanohydrins. This system was used for the preparation of a variety of cyanohydrins in high isolated yields and with up to 96% ee. Activation of the cyanide by nucleophilic attack of the Lewis base at the carbonyl carbon atom was supported experimentally.

    Secondly, convenient procedures for the synthesis of polymer-bound chiral YbCl3-pybox and Ti-salen complexes are described. The polymeric complexes were employed in cyanation of benzaldehyde.

    A T-shaped microreactor was used for screening of reaction conditions for the enantioselective cyanation of benzaldehyde using trimethylsilyl cyanide and acetyl cyanide as cyanide sources. A microreactor charged with the polymeric Tisalen complex was used for enantioselective cyanation of benzaldehyde.

    Finally, an enzymatic method for high throughput analysis of ee and conversion of products from chiral Lewis acid–Lewis base-catalysed additions of α- ketonitriles to prochiral aldehydes was developed. The method could be used for the analysis of a variety of O-acylated cyanohydrins. Microreactor technology was successfully combined with high throughput analysis for efficient catalyst optimisation.

  • 43.
    Lundgren, Stina
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Wingstrand, Erica
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Moberg, Christina
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Lewis acid-Lewis base-catalysed enantioselective addition of alpha-ketonitriles to aldehydes2007Inngår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 349, nr 3, s. 364-372Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Additions of structurally diverse alpha-ketonitriles to aromatic and aliphatic prochiral aldehydes yielding highly enantioenriched acylated cyanohydrins were achieved using a combination of a titanium salen dimer and an achiral or chiral Lewis base. In most cases high yields and high enantioselectivities were observed. The ee was moderate in the initial part of the reaction but increased over time. This could be avoided, and higher ees obtained, by keeping the titanium complex, in the presence or absence of aldehyde and ketonitrile, at -40 degrees C prior to the addition of the Lewis base. A mechanism initiated by nucleophilic attack of the tertiary amine at the carbonyl carbon atom of the ketonitile is supported by C-13 labelling experiments.

  • 44.
    Macáková, Lubica
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Interactions Between Biopolymers and Surfactants with Focus on Fluorosurfactants and Proteins2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The aim of this thesis was to obtain a better understanding of the association between surfactants and biopolymers in bulk solutions and at solid/aqueous liquid interface. In order to do this, the interactions between surfactants and biopolymers were investigated with a variety of experimental techniques.

    The main focus has been on the interactions between fluorosurfactants and proteins, which are important during electrophoresis of proteins in silica capillaries. Electrophoretic separation of positively charged proteins is often complicated by non-specific adsorption of protein onto capillary wall, while it was found to improve when cationic fluorosurfactants were added into the background buffer. We investigated the interactions between a cationic fluorosurfactant, FC134, and a positively charged protein, lysozyme. By employing Nuclear Magnetic Resonance (NMR) and tensiometry we could conclude that the cationic fluorosurfactant did not associate with positively charged lysozyme in bulk solutions. At the solid/aqueous liquid interface, the adsorption of fluorosurfactants and lysozyme onto silica was studied by the surface force technique (MASIF), ellipsometry, reflectrometry, Quartz Crystal Microbalance (QCM-D) and Atomic Force Microscopy (AFM). Cationic fluorosurfactant FC134 was found to adsorb onto the silica surface in a form of bilayer aggregates, which led to a charge reversal of the originally negatively charged substrate. The adsorption of lysozyme onto silica was also extensive and it corresponded to the more than monolayer coverage. When adsorbing from mixed solutions, the presence of the cationic fluorosurfactant in the solution led to an elimination of the lysozyme in the resulting adsorbed layer. For the lysozyme concentration of 0.2 mg/ml, which is typical for the electrophoretic separation, it was found that adsorption of protein was suppressed by more than 90% when only 30 μM of FC134 was added into the buffer. The presence of the low amounts of residual proteins in the adsorbed layers caused an enhancement of the adsorption of fluorosurfactants, which was attributed to adsorption of the fluorosurfactants between proteins in a form of large vesicles.

    The interactions between a positively charged biopolymer chitosan and an anionic surfactant sodium dodecylsulfate (SDS) were studied with respect to the effect of the ionic strength of the background electrolyte, both in the bulk solution and at the silica/liquid interface. It was shown that SDS and chitosan form complexes in the bulk solution, which reverse their charge at higher SDS concentrations. At SDS concentrations above the critical micellar concentration, large aggregates were formed, which were trapped in long-lived nonequilibrium states at both high and low ionic strengths. SDS did not adsorb at the silica/liquid interface by itself. However, by employing QCM-D and ellipsometry we detected an extensive adsorption of SDS on the silica substrate, which has been modified by adsorbed chitosan. The structure of the chitosan layer on the lowly charged silica was strongly affected by the ionic strength of the solution from which the chitosan adsorption took place. The interactions between SDS and the pre-adsorbed chitosan were found to be similar on lowly charged silica and on highly charged mica.

    A novel method based on the Bruggeman effective medium approximation was proposed for the evaluation of ellipsometric data characterizing composite adsorbed layers.

    Finally, the effect of the adsorbed layer surface roughness on the QCM-D response in liquid was studied with focus on trapped water. It was found that QCM-D effectively senses water, which is mechanically trapped inside topographical structures with the size in nano-meter scale.

  • 45.
    Mannerstedt, Karin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ekelöf, Kerstin
    Oscarson, Stefan
    Evaluation of Thioglycosides of Kdo as Glycosyl Donor2007Inngår i: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 342, nr 3-4, s. 631-637Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The use of Kdo thioglycosides as glycosyl donors using DMTST, IBr/AgOTf and NIS/AgOTf as promoters has been evaluated. Activation at low temperature allowed to escape the formation of 2,3-glycal byproducts to give glycosides in high yield and with good β-anomeric selectivity. The use of diethyl ether as solvent and (especially) isopropylidene acetals as protecting groups improved the α-anomeric selectivity. NIS/AgOTf as promoter surprisingly yielded the 3-iodo-product via the glycal intermediate.

  • 46.
    Mirpourzadeh, Sara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Development of new mimetics for the Tyr-pair of the Epoxide Hydrolase2007Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 47.
    Moberg, Christina
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Frölander, Anders
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    ORGN 31-Secondary interaction in hydroxy-containing phosphinooxazolines2007Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 234, s. 31-ORGN-Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Phosphinooxazolines, first employed by Williams, Pfaltz, and Helmchen, serve as versatile ligands for a variety of asym. catalytic reactions.  The hydroxy group in hydroxy-contg. phosphinooxazolines such as 1 can take part in hydrogen bonding to low valent metal ions, thereby affecting the conformation and, as a result, the stereochem. of catalytic reactions.  The hydroxy group is also capable of coordinating to high valent metal ions via the oxygen atom, resulting in more rigid complexes.  This leads for example to enhanced enantioselectivity in Rh- and Ir-catalyzed hydrosilylations of prochiral ketones.  The influence of these secondary interaction on the conformation and dynamics of metal complexes and on the selectivity in catalytic reactions will be discussed.

  • 48.
    Norinder, Jakob
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bogár, Krisztián
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kanupp, Lisa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    An enantioselective route to alpha-methyl carboxylic acids via metal and enzyme catalysis2007Inngår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 9, nr 24, s. 5095-5098Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dynamic kinetic resolution of allylic alcohols to allylic acetates followed by copper-catalyzed allylic substitution gave alkenes in high yields and high optical purity. Subsequent oxidative C-C double bond cleavage afforded pharmaceutically important alpha-methyl substituted carboxylic acids in high ee.

  • 49.
    Norinder, Jakob
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dynamic processes in the copper-catalyzed substitution of chiral allylic acetates leading to loss of chiral information2007Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 13, s. 4094-4102Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Copper-catalyzed α-substitution of enantiomerically pure secondary allylic esters with Grignard reagents was studied with the aim to find conditions that give racemic products. It was observed that the degree of chiral transfer is strongly dependent on the temperature. The loss of chiral information is consistent with an equilibration of the CuIII(allyl) intermediates prior to product formation. Equilibration of the reaction intermediates is of importance for a possible development of a dynamic kinetic asymmetric transformation (DYKAT) process, in which a chiral catalyst is used to produce an optically active product from a racemic substrate, by means of a dynamic equilibrium of the diastereomeric reaction intermediates.

  • 50. Odell, Luke R.
    et al.
    McCluskey, Adam
    Failes, Timothy W.
    Tiekink, Edward R. T.
    Crystal and Molecular Structures of Benzyl-(2-chloro-6-methylpyrimidin-4-yl)amine and Benzyl-(4-chloro-6-methylpyrimidin-2-yl)amine: Confirmation of Computationally Predicted Restricted Rotation2007Inngår i: Journal of Chemical Crystallography, ISSN 1074-1542, E-ISSN 1572-8854, Vol. 37, nr 12, s. 817-824Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Crystal structures for the isomeric compounds benzyl-(2-chloro-6-methylpyrimidin-4-yl)amine (1), as its hemi-hydrate, and benzyl-(4-chloro-6-methylpyrimidin-2-yl)amine (2) have been determined. Conformational differences lead to multiple molecules, i.e. two and three, in their respective structures. Layers feature in each of the crystal structures and are stabilized by substantial hydrogen-bonding interactions. Compound (1) crystallizes as a hemi-hydrate in the triclinic space group P-1 with a = 8.667(5) Å, b = 11.421(7) Å, c = 12.954(8) Å, α = 78.330(10)°, β = 84.553(10)°, γ = 75.510(9)°, and Z = 4. Compound (2) crystallizes in the monoclinic space group P21/c with a = 10.740(3) Å, b = 21.487(6) Å, c = 14.914(4) Å, β = 95.014(5)°, and Z = 12.

12 1 - 50 of 81
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