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  • 1.
    Ahlford, Katrin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lind, Jesper
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Mäler, Lena
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Adolfsson, Hans
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Rhodium-catalyzed asymmetric transfer hydrogenation of alkyl and aryl ketones in aqueous media2008In: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 10, no 8, p. 832-835Article in journal (Refereed)
    Abstract [en]

    A novel lipophilic rhodium catalyst was evaluated in the enantioselective transfer hydrogenation of ketones in water using sodium formate as the hydride donor, and in the presence of sodium docecylsulfonate. Alkyl alkyl ketones were reduced in good yields and in moderate to good enantioselectivities, and the reduction of aryl alkyl ketones proceeded with excellent enantioselectivity (up to 97% ee).

  • 2. Aili, Daniel
    et al.
    Enander, Karin
    Rydberg, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Nesterenko, Irina
    Björefors, Fredrik
    Baltzer, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Liedberg, Bo
    Folding Induced Assembly of Polypeptide Decorated Gold Nanoparticles2008In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 130, no 17, p. 5780-5788Article in journal (Refereed)
    Abstract [en]

    Reversible assembly of gold nanoparticles controlled by the homodimerization and folding of an immobilized de novo designed synthetic polypeptide is described. In solution at neutral pH, the polypeptide folds into a helix-loop-helix four-helix bundle in the presence of zinc ions. When immobilized on gold nanoparticles, the addition of zinc ions induces dimerization and folding between peptide monomers located on separate particles, resulting in rapid particle aggregation. The particles can be completely redispersed by removal of the zinc ions from the peptide upon addition of EDTA. Calcium ions, which do not induce folding in solution, have no effect on the stability of the peptide decorated particles. The contribution from folding on particle assembly was further determined utilizing a reference peptide with the same primary sequence but containing both D and L amino acids. Particles functionalized with the reference peptide do not aggregate, as the peptides are unable to fold. The two peptides, linked to the nanoparticle surface via a cysteine residue located in the loop region, form submonolayers on planar gold with comparable properties regarding surface density, orientation, and ability to interact with zinc ions. These results demonstrate that nanoparticle assembly can be induced, controlled, and to some extent tuned, by exploiting specific molecular interactions involved in polypeptide folding.

  • 3.
    Andersson, Linnéa
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry. Oorganisk kemi.
    Exploring expandable microspheres as a novel pore former in gel-cast macroporous alumina2008Licentiate thesis, monograph (Other academic)
    Abstract [en]

    Expandable microspheres have been explored as sacrificial templates for the production of macroporous ceramics. Concentrated alumina powder suspensions that contain expandable microspheres have been consolidated by gel-casting. The temperature range for the setting of the monomers and cross-linkers in the gel-casting system was tailored to allow the gas-filled polymer spheres to expand before the surrounding powder body became rigid. It has been demonstrated that it is possible to tune and tailor the porosity up to 86 % and the pore size distribution from 15 up to 150 micrometers by controlling the amount and size of the expandable microspheres. Scanning electron microscopy showed that the porosity became more and more open as the total porosity increased. This was corroborated by a preliminary study by X-ray µ Computed Tomography, which showed a very high connectivity between the pores, in a macroporous alumina body with a high porosity. The connectivity was reduced when alumina particles were deposited as a homogenous coating of on the expandable microspheres by a layer-by-layer coating process. The expandable microspheres has the advantage that a relatively low amount of organic material results in a large pore volume, which allow rapid and facile burn-out. It was demonstrated that the temperature induced expansion of the microspheres, and the associated increase of the suspension volume could be used as a novel casting method to yield macroporous alumina bodies with complex shapes. Ceramics produced with this method could find application ranging from bone scaffolds to low mass kiln furniture.

  • 4.
    Angelin, Marcus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fischer, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Crystallization-induced secondary selection from a tandem driven dynamic combinatorial resolution process2008In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 73, no 9, p. 3593-3595Article in journal (Refereed)
    Abstract [en]

    Crystallization-induced secondary selection from a tandem driven dynamic combinatorial library is presented. In a one-pot experiment, an initial nitroaldol equilibrium was kinetically driven by a tandem reaction resulting in a subsequent dynamic library of diastereoisomers. This library was then further driven by a phase change, resulting in amplification and isolation of a highly diastereomerically enriched and synthetically interesting isoindolinone.

  • 5.
    Appukkuttan, Prasad
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Axelsson, Linda
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Van der Eycken, Erik
    Larhed, Mats
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Microwave-assisted, Mo(CO)(6)-mediated, palladium-catalyzed amino-carbonylation of aryl halides using allylamine: from exploration to scale-up2008In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 49, no 39, p. 5625-5628Article in journal (Refereed)
    Abstract [en]

    Palladium-catalyzed aminocarbonylations of various (hetero)aryl halides with allylamine using Mo(CO)(6) as a solid, in situ CO source, were explored. Microwave-enhanced conditions proved to be highly useful in promoting the conversions in a mere 10-20 min with various (hetero)aryl iodides, bromides and chlorides. The scale-up of a microwave-enhanced aminocarbonylation to 25 mmol scale was performed successfully. (C) 2008 Elsevier Ltd. All rights reserved.

  • 6.
    Aydin, Juhanes
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Enantioselective palladium pincer complex catalyzed carbon carbon coupling reactions between tosylimines and various nucleophiles2008In: Abstracts of Papers, 236th ACS National Meeting, Philadelphia, PA, United States, August 17-21, 2008, Washington, DC: American Chemical Society , 2008Conference paper (Other academic)
  • 7.
    Aydin, Juhanes
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Szabó, Kálmán J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanistic considerations for the enantioselective palladium pincer complex catalyzed carbon-carbon coupling reactions2008In: Abstracts of Papers, 236th ACS National Meeting, Philadelphia, PA, United States, August 17-21, 2008, Washington, DC: American Chemical Society , 2008Conference paper (Other academic)
  • 8.
    Ayesa Alvarez, Susana
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Design and Synthesis of Amine Building Blocks and Protease Inhibitors2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The first part of this thesis addresses the design and synthesis of amine building blocks accomplished by applying two different synthetic procedures, both of which were developed using solid-phase chemistry. Chapter 1 presents the first of these methods, entailing a practical solid-phase parallel synthesis route to N-monoalkylated aminopiperidines and aminopyrrolidines achieved by selective reductive alkylation of primary and/or secondary amines. Solid-phase NMR spectroscopy was used to monitor the reactions for which a new pulse sequence was developed. The second method, reported in Chapter 2, involves a novel approach to the synthesis of secondary amines starting from reactive alkyl halides and azides. The convenient solid-phase protocol that was devised made use of the Staudinger reaction in order to accomplish highly efficient alkylations of N-alkyl phosphimines or N-aryl phosphimines with reactive alkyl halides.

    The second part of the thesis describes the design and synthesis of three classes of protease inhibitors targeting the cysteine proteases cathepsins S and K, and the serine protease hepatitis C virus (HCV) NS3 protease. Chapter 4 covers the design, solid-phase synthesis, and structure-activity relationships of 4-amidofurane-3-one P1-containing inhibitors of cathepsin S and the effects of P3 sulfonamide groups on the potency and selectivity towards related cathepsin proteases. This work resulted in the discovery of highly potent and selective inhibitors of cathepsin S. Two parallel solid-phase approaches to the synthesis of a series of aminoethylamide inhibitors of cathepsin K are presented in Chapter 5. Finally, Chapter 6 reports peptide-based HCV NS3 protease inhibitors containing a non-electrophilic allylic alcohol moiety as P1 group and also outlines efforts to incorporate this new template into low-molecular-weight drug-like molecules.

  • 9.
    Ayesa, Susana
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Samuelsson, Bertil
    Classon, Björn
    A One-Pot, Solid-Phase Synthesis of Secondary Amines from Reactive Alkyl Halides and an Alkyl Azide2008In: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, no 1, p. 77-79Article in journal (Refereed)
  • 10.
    Bartoszewicz, Agnieszka
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Livendahl, Madeleine
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of b-Hydroxy Ketones from Allylic Alcohols via Catalytic Formation of Ruthenium Enolates2008In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 14, no 34, p. 10547-10550Article in journal (Refereed)
    Abstract [en]

    The most efficient Ru-catalyzed isomerization–aldol reaction from allylic alcohols has been achieved by using [η5-(Ph5Cp)Ru(CO)2Cl] as the catalyst. The bulky pentaphenylcyclopentadienyl ligand on the ruthenium atom prevents protonation at the oxygen of the Ru–enolate intermediate and completely suppresses the formation of unwanted ketone byproducts (see scheme). The domino transformation is as good as it can be: aldols are obtained in quantitative yields at ambient temperature.

  • 11.
    Berglund, Per
    KTH, School of Biotechnology (BIO), Biochemistry.
    Asymmetric Organic Synthesis with Enzymes: Edited by Vicente Gotor, Ignacio Alfonso and Eduardo Garcia-Urdiales2008In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 47, no 35, p. 6514-6515Article, book review (Other academic)
  • 12.
    Bergson, Göran
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Linderberg, Jan
    Is a Proposed Reaction Mechanism Free from Unnecessary Assumptions?: Occam's Razor Applied in a Mathematical Way To Complex First-Order Reaction Systems2008In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, no 112, p. 4235-4240Article in journal (Refereed)
    Abstract [en]

    Following Occam's principle, a proposed reaction mechanism should not contain assumptions about the existence of reactive intermediates and reaction paths that are unnecessary for a full description and interpretation of the available facts. A mechanism refers, in this paper, to a proposed reaction scheme or network that represents the reactions supposed to be going on in a complex reaction system with observable species as well as unobservable reactive intermediates. The scope is limited here to (pseudo) first-order reactions and the steady-state approximation is invoked in order to relate unknown mechanistic rate constants to experimentally determined ones, and, when available, theoretically calculated quantities. When the resulting, nonlinear system of equations admits a unique solution within a physically reasonable domain, it is concluded that the reaction mechanism fulfills Occam's principle. Otherwise, there are many or no solutions. No subjective or qualitative arguments enter the procedure and the outcome is not negotiable.

  • 13.
    Bielawski, Marcin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Efficient and High-Yielding Routes to Diaryliodonium Salts2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis summarizes three novel and general reaction protocols for the synthesis of diaryliodonium salts. All protocols utilize mCPBA as oxidant and the acids used are either TfOH, to obtain triflate salts, or BF3•Et2O that gives the corresponding tetrafluoroborate salts in situ.

    Chapter two describes the reaction of various arenes and aryl iodides, delivering electron-rich and electron-deficient triflates in moderate to excellent yields.

    In chapter three, it is shown that the need of aryl iodides can be circumvented, as molecular iodine can be used together with arenes in a direct one-pot, three-step synthesis of symmetric diaryliodonium triflates.

    The final and fourth chapter describes the development of a sequential one-pot reaction from aryl iodides and boronic acids, delivering symmetric and unsymmetric, electron-rich and electron-deficient iodonium tetrafluoroborates in moderate to excellent yields. This protocol was developed to overcome mechanistic limitations existing in the protocols described in chapter two and three.

    The methodology described in this thesis is the most general, efficient and high-yielding existing up to date, making diaryliodonium salts easily available for various applications in synthesis.

  • 14.
    Bielawski, Marcin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Aili, David
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Olofsson, Berit
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Regiospecific One-Pot Synthesis of Diaryliodonium Tetrafluoroborates from Arylboronic Acids and Aryl Iodides2008In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 73, no 12, p. 4602-4607Article in journal (Refereed)
    Abstract [en]

    Diaryliodonium salts have recently received considerable attention as mild arylation reagents in organic synthesis. This paper describes a regiospecific, sequential one-pot synthesis of symmetrical and unsymmetrical diaryliodonium tetrafluoroborates, which are the most popular salts in metal-catalyzed arylations. The protocol is fast and high-yielding and has a large substrate scope. Furthermore, the corresponding diaryliodonium triflates can conveniently be obtained via an in situ anion exchange.

  • 15. Blixt, Ola
    et al.
    Hoffmann, Julia
    Svensson, Stefan
    Norberg, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Pathogen specific carbohydrate antigen microarrays: a chip for detection of Salmonella O-antigen specific antibodies2008In: Glycoconjugate Journal, ISSN 0282-0080, E-ISSN 1573-4986, Vol. 25, no 1, p. 27-36Article in journal (Refereed)
    Abstract [en]

    A Salmonella O-antigen microarray was developed by covalent coupling of oligosaccharide antigens specific for serogroups Salmonella enterica sv. Paratyphi (group A), Typhimurium (group B) and Enteritidis (group D). Antibodies were correctly detected in sera from patients with culture verified salmonellosis. High serogroup-specificity was seen with the disaccharide antigens. With the larger antigens, containing the backbone sequence Man alpha 1-2Rha alpha 1-2Gal (MRG), common backbone-specific antibodies (O-antigen 12) were also detected. This is "proof of principle" that pathogen-specific carbohydrate antigen microarrays constitute a novel technology for rapid and specific serological diagnosis in either individual patients or larger sero-epidemiological and vaccine studies.

  • 16.
    Borén, Linnéa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Enantioselective Synthesis of Sec-Alcohol Derivatives and Diols via Combined Ruthenium and Enzyme Catalysis2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The first part of this thesis describes the synthesis of enantiopure secondary alcohol derivatives. These syntheses are carried out via the combination of an enzyme as a resolution catalyst and a ruthenium catalyst as a racemization catalyst, in what is called dynamic kinetic resolution (DKR). By varying the resolution catalyst enantio-complementary processes can be obtained. A lipase (PS-C II) catalyzed DKR of γ-hydroxyamides gave the corresponding (R)-acetates in high yields and with high enantioselectivity. The synthetic usefulness of these obtained (R)-acetates was demonstrated by the synthesis of (R)-5-methyltetrahydrofurane-2-one. A protease (Subtilisin Carlsberg) catalyzed DKR of various secondary alcohols gave the corresponding (S)-acetates in high yields and with high enantioselectivity. In the second part of this thesis the DKR process has been extended into a dynamic kinetic asymmetric transformation (DYKAT) of diols. Various 1,5- and 1,4-diols were transformed into enantiopure diacetates in a lipase (CALB and PS-C II) catalyzed DYKAT. The synthetic utility of the obtained enantiopure diacetates were demonstrated by the synthesis of various enantiopure disubstituted heterocycles.

  • 17.
    Byrne, Christopher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Church, Tamara
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Kramer, John
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Coates, Geoffrey
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Catalytic Synthesis of B3-Amino Acid Derivatives from a-Amino Acids***2008In: Angew. Chem. Int. Ed., no 47, p. 3979-3983Article in journal (Refereed)
  • 18.
    Chatterjee, Subhrangsu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Bioorganic Chemistry.
    Pathmasiri, Wimal
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Bioorganic Chemistry.
    Chattopadhyaya, Jyoti
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Bioorganic Chemistry.
    Sequence-specific Solution Structures of the Four Isosequential Pairs of Single-stranded DNAs and RNAs2008In: Nature PrecedingsArticle in journal (Other academic)
    Abstract [en]

    The role of the sequence-context in the self-organization of four single-stranded (ss) isosequential pairs of DNAs (1 – 4) and RNAs (5 – 8), [d/r-(5’C1A2X3G4Y5A6C7): X3 = A or C, Y5 = A or C; sequence variations: 22 = 4], has been elucidated by NMR-constrained Molecular Dynamics (MD) simulations (2 ns). Following sequence-specific observations have been made from the solution NMR and the NMR constrained MD simulation study: (i) Analysis of the NOESY footprints, mainly (H8/H6)n to (H1’ and H3’)n-1 contacts, of ssDNAs (1 – 4) and ssRNAs (5 – 8) in the aqueous medium have shown that all ssDNAs (1 – 4) and ssRNAs (5 – 8) adopt right handed stacked helical structures in the NMR time scale. (ii) Intra-residual cross-peak intensities for the H(8/6)n- H(1’/2’/2’’/H3’)n contacts in ssDNAs and ssRNAs are stronger at the 3’-ends in comparison with those at the 5’-ends, suggesting that the dynamics of the nucleobases at the 3’-end are more restricted, whereas those at the 5’-end are more flexible. (iii) This relative NMR found mobility is consistent with the final RMSd calculations of the final NMR-MD structures of ssDNAs and ssRNAs. They show that the 5’-end nucleobases have higher RMSd values compared to those at the 3’-end, except for the sequence d/r(5’C1A2A3G4A5A6C7). (iv) Relative nOe intensities of inter-residual H(8/6)n – H(1’)n-1 and H(8/6)n – H(3’)n-1 contacts, as well as NMR observed fluctuations in the sugar conformations, for ssDNAs (1 – 4) and ssRNAs (5 – 8) show that no ssDNA or ssRNA adopts either a typical B-type DNA or A-type RNA form. (v) In the final NMR-MD structures all the [H8/6N(n)—H1’N(n-1)/ H3’N(n-1), N = A, G, C] distances in different isosequential pairs of ssDNA (1 – 4) and ssRNA (5 – 8) change depending upon the sequence context of the single-stranded nucleic acids. Both in the deoxy and ribo series, it is the purine-rich sequences [d/r-(5’C1A2A3G4A5A6C7) which form the most stable self-organized right-handed helical structures because of the favorable purine-purine stacking interactions. (vi) Stacking pattern at each of the dinucleotide steps show that the base-base nearest neighbor stacking interactions depend solely upon the sequence contexts of the respective ssDNAs (1 – 4) and ssRNAs (5 – 8). See pages 47 – 145 for Supplementary Information for detailed spectroscopic data.

  • 19.
    Cheruku, Pradeep
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Ali, Muhammad
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Neudoerfl, Joerg-M
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Development of new thiazole-based iridium catalysts and their applications in the asymmetric hydrogenation of trisubstituted olefins2008In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 6, no 2, p. 366-373Article in journal (Refereed)
    Abstract [en]

    New thiazole-based chiral N,P-ligands that are open-chain analogues of known cyclic thiazole ligands have been synthesized and evaluated in the iridium-catalyzed asymmetric hydrogenation of trisubstituted olefins. Chirality was introduced into the ligands through a highly diastereoselective alkylation using Oppolzer's camphorsultam as chiral auxiliary. In general, the new catalysts are as reactive and selective as their cyclic counterparts for the asymmetric hydrogenation of various trisubstituted olefins.

  • 20. Cheruku, Pradeep
    et al.
    Paptchikhine, Alexander
    Ali, Muhammad
    Neudörfl, Jörg-M.
    Andersson, Pher
    Development of new thiazole-based iridium catalysts and their applications in the asymmetric hydrogenation of trisubstituted olefins2008In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 6, p. 366-373Article in journal (Refereed)
  • 21. Coleman, V. A.
    et al.
    Knut, Ronny
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Karis, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Grennberg, H.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Jansson, U.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Quinlan, R.
    Holloway, B. C.
    Sanyal, Biplab
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Theory.
    Eriksson, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Theory.
    Defect Formation In Graphene Nanosheets By Acid Treatment: An X-Ray Absorption Spectroscopy And Density Functional Theory Study2008In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 41, no 6, p. 062001-4Article in journal (Refereed)
    Abstract [en]

    In-plane defects have been introduced into graphene nanosheets by treatment with hydrochloric acid. Acid treatment induces bond cleavage in the C–C network via electrophilic attack. These resultant vacancy sites will then undergo further reactions with the surrounding ambient to produce C–O and C–H bonds. A σ* resonance at 287 eV in the carbon K-edge x-ray absorption spectra is observed with acid treatment and is assigned to C–O states. Theoretical modelling of a di-vacancy in a graphene bilayer reproduces all essential features of this resonance and in addition predicts a metallic conductivity of states around this vacancy. The possibility of engineering the properties of graphene via the routes explored here is an important step towards establishing strategies for building devices based on this material.

  • 22.
    Danielsson, Marie
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kännaste, Astrid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lindström, Anders
    School of Industrial Technology and Management, Dalarna University.
    Hellqvist, Claes
    Department of Ecology, Swedish University of Agricultural Sciences.
    Stattin, Eva
    School of Industrial Technology and Management, Dalarna University.
    Långström, Bo
    Department of Ecology, Swedish University of Agricultural Sciences.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Mini-seedlings of Picea abies are less attacked by Hylobius abietis than conventional ones: Is plant chemistry the explanation?2008In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 23, no 4, p. 299-306Article in journal (Refereed)
    Abstract [en]

    The pine weevil, Hylobius abietis (L.), is a major pest in conifer reforestation areas in the Palaearctic region. Size and chemistry of the seedlings may explain the damage rates in plantations. The performance of 10-week containerized seedlings (mini-seedlings) was compared with 1-year-old conventional seedlings of Norway spruce, Picea abies (L.), in a field experiment in central Sweden. After 2 years the weevil damage was lower for the mini-seedlings than for the conventional seedlings (3.5 vs 55%). After 3 years, the overall survival was 82 and 75%, respectively. Weevil damage was the main cause of mortality for conventional seedlings, whereas mini-seedlings mainly died from drought. Volatiles of the two seedling types were compared by solid-phase microextraction-gas chromatography -mass spectrometry (SPME-GC-MS). Unwounded mini-seedlings and conventional seedlings differed in their compositions of monoterpenes and sesquiterpenes. Miniseedlings mainly emitted limonene, known to be repellent to the pine weevil. When wounded, green leaf volatiles were released by mini-seedlings while the pine weevil attractant alpha-pinene was released by conventional seedlings. Volatiles may partly explain the mini-seedlings' resistance against weevil attack. Further studies are needed to clarify how long this miniseedling effect remains.

  • 23.
    Diéguez, Montserrat
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Mazuela, Javier
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Pàmies, Oscar
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Verendel, Johan
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Chiral Pyranoside Phosphite - Oxazolines: A New Class of Ligand for Asymmetric Catalytic Hydrogenation of Alkenes2008In: J. Am. Chem. Soc., no 130, p. 7208-7209Article in journal (Refereed)
  • 24.
    Dong, Hai
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Pei, Zhichao
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Supramolecular activation in triggered cascade inversion2008In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, p. 1359-1361Article in journal (Refereed)
    Abstract [en]

    An unexpected activation effect from combinations of anionic reagent and amine base resulted in dramatic rate enhancements in multiple carbohydrate cascade inversion.

  • 25.
    Dong, Hai
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Rahm, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Brinck, Tore
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Supramolecular Control in Carbohydrate Epimerization: Discovery of a New Anion Host−Guest System2008In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 130, p. 15270-15271Article in journal (Refereed)
    Abstract [en]

    A new anion-carbohydrate recognition system is described. Pyranosides with axial protons in 1-, 3-, and 5-position proved efficient, forming relatively strong complexes between the anion and the B-face of the carbohydrate. This system could furthermore be used in supramolecular control in Lattrell-Dax epimerization reactions, leading to either activation or deactivation effects.

  • 26.
    Eklöf, Anders M.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Lowcoordinated Silicon and Hypercoordinated Carbon: Structure and Stability of Silicon Analogs of Alkenes and Carbon Analogs of Silicates2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Quantum chemical studies on lowcoordinated group 14-16 compounds have been performed. This thesis focuses particularly on silenes influenced by reverse Siδ-=Cδ+ bond polarization. Hypercoordinated carbon compounds are also studied.

    The geometries from calculations with several common computationally inexpensive methods have been tested against high level CCSD/cc-pVTZ geometries for a series of substituted silenes. Hybrid HF/DFT methods performed best among the inexpensive methods tested for silenes.

    Heavy alkenes strongly influenced by reverse polarization are found to have less exothermic dimerization energies for both head-to-head and head-to-tail dimerizations, and to have higher activation energies for water addition than naturally polarized heavy alkenes.

    We also investigated solvated lithium, magnesium and potassium silenolates and found that lithium and magnesium ions coordinate preferably to O, giving their SiC bond some double bond character.

    Reverse polarized 2-siloxy-, 2-thiosiloxy-, and 2-(N-sila-N-methyl)-silenes could according to calculations be formed thermolytically from the corresponding tetrasilanes as transient species. It was, however, found that silenes highly influenced by π-conjugative reverse polarization have low barriers for the back-reaction, and thus these silenes are more difficult to form as stable species than naturally polarized silenes.

    It is also found that conjugated 1-siladienes, formed by electrocyclic ring-opening of 1-silacyclobut-2-enes, which are highly influenced by π-conjugative reverse polarization, have higher barriers for electrocyclization back to starting material than naturally polarized 1-siladienes.

    It is found that CHe54+, CHe64+, CNe54+, and CNe64+ are the closest carbon analogs of SiH5-, SiH62-, SiF5- and SiF62-, respectively. However, due to their exothermic dissociation reaction, these very high-lying local minima will be impossible to reach experimentally.

  • 27.
    Ericsson, Daniel J.
    et al.
    1Department of Cell and Molecular Biology, Uppsala University, Biomedical Center.
    Kasrayan, Alex
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Johansson, Patrik
    1Department of Cell and Molecular Biology, Uppsala University, Biomedical Center.
    Bergfors, Terese
    1Department of Cell and Molecular Biology, Uppsala University, Biomedical Center.
    Sandström, Anders G.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mowbray, Sherry L.
    Department of Molecular Biology, Swedish University of Agricultural Sciences, Biomedical Center.
    X-Ray structure of Candida antarctica lipase A shows a novel lid structure and a likely mode of interfacial activation2008In: Journal of Molecular Biology, ISSN 0022-2836, Vol. 376, no 1, p. 109-119Article in journal (Refereed)
    Abstract [en]

    In nature, lipases (EC 3.1.1.3) catalyze the hydrolysis of triglycerides to form glycerol and fatty acids. Under the appropriate conditions, the reaction is reversible, and so biotechnological applications commonly make use of their capacity for esterification as well as for hydrolysis of a wide variety of compounds. In the present paper, we report the X-ray structure of lipase A from Candida antarctica, solved by single isomorphous replacement with anomalous scattering, and refined to 2.2-Å resolution. The structure is the first from a novel family of lipases. Contrary to previous predictions, the fold includes a well-defined lid as well as a classic α/β hydrolase domain. The catalytic triad is identified as Ser184, Asp334 and His366, which follow the sequential order considered to be characteristic of lipases; the serine lies within a typical nucleophilic elbow. Computer docking studies, as well as comparisons to related structures, place the carboxylate group of a fatty acid product near the serine nucleophile, with the long lipid tail closely following the path through the lid that is marked by a fortuitously bound molecule of polyethylene glycol. For an ester substrate to bind in an equivalent fashion, loop movements near Phe431 will be required, suggesting the primary focus of the conformational changes required for interfacial activation. Such movements will provide virtually unlimited access to solvent for the alcohol moiety of an ester substrate. The structure thus provides a basis for understanding the enzyme's preference for acyl moieties with long, straight tails, and for its highly promiscuous acceptance of widely different alcohol and amine moieties. An unconventional oxyanion hole is observed in the present structure, although the situation may change during interfacial activation

  • 28. Eriksson, Carina
    et al.
    Månsson, Per E.
    Sjödin, Kristina
    Schlyter, Fredrik
    Antifeedants and feeding stimulants in bark extracts of ten woody non-host species of the pine weevil, Hylobius abietis2008In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 34, no 10, p. 1290-1297Article in journal (Refereed)
    Abstract [en]

    Bark of ten woody species, known to be rejected as a food source by the pine weevil, Hylobius abietis, were sequentially extracted by a Soxhlet apparatus with pentane followed by methanol. Species were alder (Alnus glutinosa), aspen (Populus tremula), beech (Fagus sylvatica), guelder rose (Viburnum opulus), holly (Ilex aquifolium), horse chestnut (Aesculus hippocastanum), lilac (Syringa vulgaris), spindle tree (Evonymus europaeus), walnut (Juglans regia), and yew (Taxus baccata). Bark of each species was collected in southern Scandinavia during the summer. Resulting extracts were tested for antifeedant activity against the pine weevil by a micro-feeding choice assay. At a dose corresponding to that in the bark, methanol extracts from Aesculus, Taxus, Ilex, and Populus were antifeedant active, while pentane extracts of Aesculus, Fagus, Syringa, and Viburnum were stimulatory. Four known antifeedants against H. abietis, the straight-chained carboxylic acids, hexanoic and nonanoic acid (C6 and C9), carvone, and carvacrol were identified by gas chromatography (GC)-mass spectrometry (MS) in several extracts. The major constituents were identified and tested for feeding deterrence. The aromatic compounds benzyl alcohol and 2-phenylethanol are new non-host plant-derived feeding deterrents for the pine weevil. Additionally, two feeding stimulants, beta-sitosterol and 5-(hydroxymethyl)-2-furaldehyde, were identified. One active methanol extract of Aesculus bark was sequentially fractionated by liquid chromatography, and major compounds were tentatively identified as branched alcohols and esters of hexanoic acid. Five commercially available hexanoate esters and two commercially available branched alcohols were identified as new active antifeedants. Both stimulatory and inhibiting compounds were found in the same extracts and co-eluted in the same or adjacent fractions. The mix of semiochemicals of opposite activity in each extract or fraction could explain the stimulatory-, inhibitory-, or sometimes neutral activity. Generally, such co-occurrence confounds the isolation of antifeedants.

  • 29.
    Erlandsson, Maria
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Karimi, Farhad
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Takahashi, Kayo
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Långström, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    18F-Labelled vorozole analogues as PET tracer for aromatase2008In: J. Label Compd Radiopharm, no 51, p. 207-212Article in journal (Refereed)
  • 30. Fristrup, Peter
    et al.
    Ahlquist, Mårten
    Department of Chemistry, Technical University of Denmark.
    Tanner, David
    Norrby, Per-Ola
    On the Nature of the Intermediates and the Role of Chloride Ions in Pd-Catalyzed Allylic Alkylations: Added Insight from Density Functional Theory2008In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 112, no 50, p. 12862-12867Article in journal (Refereed)
    Abstract [en]

    The reactivity of intermediates in palladium-catalyzed allylic alkylation was investigated using DFT (B3LYP) calculations including a PB-SCRF solvation model. In the presence of both phosphine and chloride ligands, the allyl intermediate is in equilibrium between a cationic eta(3)-allylPd complex with two phosphine ligands, the corresponding neutral complex with one phosphine and one chloride ligand, and a neutral eta(1)-allylPd complex with one chloride and two phosphine ligands. The eta(1)-complex is unreactive toward nucleophiles. The cationic eta(3)-complex is the intermediate most frequently invoked in the title reaction, but in the presence of halides, the neutral, unsymmetrically substituted eta(3)-CoMplex will be formed rapidly from anionic Pd(0) complexes in solution. Since the latter will prefer both leaving group ionization and reaction with nucleophiles in the position trans to phosphorus, it can rationalize the observed "memory effect" (a regioretention) in the title reaction, even in the absence of chiral ligands.

  • 31.
    Haugaard-Kedström (published under the name Haugaard-Jönsson), Linda M.
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Hossain, Mohammed Akhter
    Daly, Norelle L.
    Bathgate, Ross A.D.
    Wade, John D.
    Craik, David J.
    Rosengren, Johan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Structure of the R3/I5 chimeric relaxin peptide, a selective GPCR135 and GPCR142 agonist2008In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 283, no 35, p. 23811-23818Article in journal (Refereed)
    Abstract [en]

    The human relaxin family comprises seven peptide hormones with various biological functions mediated through interactions with G-protein-coupled receptors. Interestingly, among the hitherto characterized receptors there is no absolute selectivity toward their primary ligand. The most striking example of this is the relaxin family ancestor, relaxin-3, which is an agonist for three of the four currently known relaxin receptors: GPCR135, GPCR142, and LGR7. Relaxin-3 and its endogenous receptor GPCR135 are both expressed predominantly in the brain and have been linked to regulation of stress and feeding. However, to fully understand the role of relaxin-3 in neurological signaling, the development of selective GPCR135 agonists and antagonists for in vivo studies is crucial. Recent reports have demonstrated that such selective ligands can be achieved by making chimeric peptides comprising the relaxin-3 B-chain combined with the INSL5 A-chain. To obtain structural insights into the consequences of combining A-and B-chains from different relaxins we have determined the NMR solution structure of a human relaxin-3/INSL5 chimeric peptide. The structure reveals that the INSL5 A-chain adopts a conformation similar to the relaxin-3 A-chain, and thus has the ability to structurally support a native-like conformation of the relaxin-3 B-chain. These findings suggest that the decrease in activity at the LGR7 receptor seen for this peptide is a result of the removal of a secondary LGR7 binding site present in the relaxin-3 A-chain, rather than conformational changes in the primary B-chain receptor binding site. 

  • 32.
    Hirner, Sebastian
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Kirchner, Donata Katharina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Somfai, Peter
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Synthesis of alpha-Amino Acids by Umpolung of Weinreb Amide Enolates2008In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 33, p. 5583-5589Article in journal (Refereed)
    Abstract [en]

    An efficient and diastereoselective synthesis of alpha-amino acids from readily available starting materials has been developed. The key feature of this reaction is an umpolung of a glycine-derived enolate, providing an alternative approach for the synthesis of alpha-amino acids.

  • 33. Hossain, M. Akhter
    et al.
    Bathgate, Ross A.D.
    Kong, Chze K.R.
    Shabanpoor, Fazel
    Zhang, Suode
    Haugaard-Kedström (published under the name Haugaard-Jönsson), Linda M.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Rosengren, Johan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Tregear, Geoffrey W.
    Wade, John D.
    Synthesis, conformation, and activity of human insulin-like peptide 5 (INSL5)2008In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 9, no 11, p. 1816-1822Article in journal (Refereed)
    Abstract [en]

    Insulin-like peptide 5 (INSL5) was first identified through searches of the expressed sequence tags (EST) databases. Primary sequence analysis showed it to be a prepropeptide that was predicted to be processed in vivo to yield a two-chain sequence (A and B) that contained the insulin-like disulfide cross-links. The high affinity interaction between INSL5 and the receptor RXFP4 (GPCR142) coupled with their apparent coevolution and partially overlapping tissue expression patterns strongly suggest that INSL5 is an endogenous ligand for RXFP4. Given that the primary function of the INSL5–RXFP4 pair remains unknown, an effective means of producing sufficient quantities of this peptide and its analogues is needed to systematically investigate its structural and biological properties. A combination of solid-phase peptide synthesis methods together with regioselective disulfide bond formation were used to obtain INSL5. Both chains were unusually resistant to standard synthesis protocols and required highly optimized conditions for their acquisition. In particular, the use of a strong tertiary amidine, DBU, as Nα-deprotection base was required for the successful assembly of the B chain; this highlights the need to consider incomplete deprotection rather than acylation as a cause of failed synthesis. Following sequential disulfide bond formation and chain combination, the resulting synthetic INSL5, which was obtained in good overall yield, was shown to possess a similar secondary structure to human relaxin-3 (H3 relaxin). The peptide was able to inhibit cAMP activity in SK-N-MC cells that expressed the human RXFP4 receptor with a similar activity to H3 relaxin. In contrast, it had no activity on the human RXFP3 receptor. Synthetic INSL5 demonstrates equivalent activity to the recombinant-derived peptide, and will be an important tool for the determination of its biological function.

  • 34. Hossain, M. Akhter
    et al.
    Rosengren, Johan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Haugaard-Kedström (published under the name Haugaard-Jönsson), Linda M.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Zhang, Suode
    Layfield, Sharon
    Ferraro, Tania
    Daly, Norelle L.
    Tregear, Geoffrey W.
    Wade, John D.
    Bathgate, Ross A.D.
    The A-chain of the human relaxin family peptides has distinct roles in the binding and activation of the different relaxin family peptide receptors2008In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 283, no 25, p. 17287-17297Article in journal (Refereed)
    Abstract [en]

    The relaxin peptides are a family of hormones that share a structural fold characterized by two chains, A and B, that are cross-braced by three disulfide bonds. Relaxins signal through two different classes of G-protein-coupled receptors (GPCRs), leucine-rich repeat-containing GPCRs LGR7 and LGR8 together with GPCR135 and GPCR142, now referred to as the relaxin family peptide (RXFP) receptors 1-4, respectively. Although key binding residues have been identified in the B-chain of the relaxin peptides, the role of the A-chain in their activity is currently unknown. A recent study showed that INSL3 can be truncated at the N terminus of its A-chain by up to 9 residues without affecting the binding affinity to its receptor RXFP2 while becoming a high affinity antagonist. This suggests that the N terminus of the INSL3 A-chain contains residues essential for RXFP2 activation. In this study, we have synthesized A-chain truncated human relaxin-2 and -3 (H2 and H3) relaxin peptides, characterized their structure by both CD and NMR spectroscopy, and tested their binding and cAMP activities on RXFP1, RXFP2, and RXFP3. In stark contrast to INSL3, A-chain-truncated H2 relaxin peptides lost RXFP1 and RXFP2 binding affinity and concurrently cAMP-stimulatory activity. H3 relaxin A-chain-truncated peptides displayed similar properties on RXFP1, highlighting a similar binding mechanism for H2 and H3 relaxin. In contrast, A-chain-truncated H3 relaxin peptides showed identical activity on RXFP3, highlighting that the B-chain is the sole determinant of the H3 relaxin-RXFP3 interaction. Our results provide new insights into the action of relaxins and demonstrate that the role of the A-chain for relaxin activity is both peptide- and receptor-dependent. 

  • 35.
    Ibrahem, Ismail
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Rios, Ramon
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Vesely, Jan
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zhao, Gui-Ling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Cordova, Armando
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Catalytic enantioselective 5-hydroxyisoxazolidine synthesis: An asymmetric entry to beta-amino acids2008In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, no 7, p. 1153-1157Article in journal (Refereed)
    Abstract [en]

    The highly chemo- and enantioselective organocatalytic tandem reaction between N-carbamate-protected hydroxylamines and a,p-unsaturated aldehydes is presented. The reaction represents a unique entry for the asymmetric synthesis of 5-hydroxyisoxazolidines, oxazolidin-5-ones or gamma-hydroxyamino alcohols in high yields and 90-99% ee. A procedure for the conversion of the oxazolidin-5-ones into the corresponding beta-amino acids is also described.

  • 36.
    Johansson, Susanne
    Umeå University, Faculty of Science and Technology, Chemistry.
    Design and Synthesis of Sialic Acid Conjugates as Inhibitors of EKC-causing Adenoviruses2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The combat against viral diseases has been, and still is, a major challenge in the field of drug development. Viruses are intracellular parasites that use the host cell ma-chinery for their replication and release. Therefore it is difficult to target and destroy the viral particle without disturbing the essential functions of the host cell. This thesis describes studies towards antiviral agents targeting adenovirus type 37 (Ad37), which causes the severe ocular infection epidemic keratoconjunctivitis (EKC). Cell surface oligosaccharides serve as cellular receptors for many pathogens, including viruses and bacteria. For EKC-causing adenoviruses, cell surface oligo-saccharides with terminal sialic acid have recently been shown to be critical for their attachment to and infection of host cells. The work in this thesis support these re-sults and identifies the minimal binding epitope for viral recognition. As carbo-hydrate–protein interactions in general, the sialic acid–Ad37 interaction is very weak. Nature overcomes this problem and vastly improves the binding affinity by presenting the carbohydrates in a multivalent fashion. Adenoviruses interact with their cellular receptors via multiple fiber proteins, whereby it is likely that the ideal inhibitor of adenoviral infections should be multivalent. This thesis includes design and synthesis of multivalent sialic acid glycoconjugates that mimic the structure of the cellular receptor in order to inhibit adenoviral attachment to and infection of human corneal epithelial (HCE) cells. Synthetic routes to three different classes of sialic acid conjugates, i.e. derivatives of sialic acid, 3’-sialyllactose and N-acyl modified sialic acids, and their multivalent counterparts on human serum albumine (HSA) have been developed. Evaluation of these conjugates in cell binding and cell infectivity assays revealed that they are effective as inhibitors. Moreover the results verify the hypothesis of the multivalency effect and clearly shows that the power of inhibition is significantly increased with higher orders of valency. Potential inhibi-tors could easily be transferred to the eye using a salve or eye drops, and thereby they would escape the metabolic processes of the body, a major drawback of using carbohydrates as drugs. The results herein could therefore be useful in efforts to develop an antiviral drug for treatment of EKC.

  • 37.
    Jullian, Carolina
    et al.
    Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile.
    Morales, Javier O.
    Departamento de Química Orgánica y Fisicoquímica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile.
    Zapata-Torres, Gerald
    Departamento de Química Inorgánica y Analítica, Facultad de de Ciencias Químicas y Farmacéuticas, Universidad de Chile.
    Aguilera, Benjamín
    Departamento de Química Inorgánica y Analítica, Facultad de de Ciencias Químicas y Farmacéuticas, Universidad de Chile.
    Rodriguez, Jorge
    Departamento de Química Inorgánica y Analítica, Facultad de de Ciencias Químicas y Farmacéuticas, Universidad de Chile.
    Arán, Vicente
    Instituto de Química Médica, CSIC.
    Olea-Azar, Claudio
    Departamento de Química Inorgánica y Analítica, Facultad de de Ciencias Químicas y Farmacéuticas, Universidad de Chile.
    Characterization, phase-solubility, and molecular modeling of inclusion complex of 5-nitroindazole derivative with cyclodextrins.2008In: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, E-ISSN 1464-3391, Vol. 16, no 9, p. 5078-5084Article in journal (Refereed)
    Abstract [en]

    The slightly water-soluble 5-nitroindazole derivative (5-NI) and its inclusion with either beta-cyclodextrin (betaCD) or Heptakis (2,6-di-O-methyl)-beta-cyclodextrin (DMbetaCD) were investigated. The stoichiometric ratios and stability constants describing the extent of formation of the complexes were determined by phase-solubility measurements obtaining type-A(L) diagrams in both cases. According to the continuous variation method (Job's plot) a 1:1 stoichiometry has been proposed for the complexes. Also electrochemical studies were carried out on both CDs complexes, where the observed change in the E(PC) value for DMbetaCD indicated a lower feasibility of the nitro group reduction. The detailed spatial configuration is proposed based on two-dimensional NMR methods. These results are further interpreted using molecular modeling studies. The latter results are in good agreement with the experimental data.

  • 38.
    Kalek, Marcin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Stawinski, Jacek
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Palladium-catalyzed C-P bond formation: Mechanistic studies on the ligand substitution and the reductive elimination. An intramolecular catalysis by the acetate group in PdII complexes2008In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 27, no 22, p. 5876-5888Article in journal (Refereed)
    Abstract [en]

    Ligand substitution and reductive elimination of the palladium-catalyzed C−P bond forming cross-coupling were investigated in depth. It was found that for PhPdII(PPh3)2X (X = I, Br, Cl) complexes, a step commonly referred to as ligand substitution commenced with coordination of an H-phosphonate diester, followed by its deprotonation to form an equilibrium mixture of penta- and tetracoordinate palladiumphosphonate intermediates, from which reductive elimination of the product (diethyl phenylphosphonate) occurred. For the acetate counterpart, PhPdII(PPh3)2(OAc), the incorporation of a phosphonate moiety to the complex was preceded by a rate-determining removal of the supporting phosphine ligand, facilitated by an intramolecular catalysis by the acetate group. Both the reaction steps, i.e., formation of palladiumphosphonate intermediates and reductive elimination, were significantly faster for the acetate versus halides containing PdII complexes investigated. Similar observations were found to be true also for bidentate ligand complexes [(dppp)PdII(Ph)X]; however, in this instance, a single palladiumphosphonate intermediate, (dppp)PdII(Ph)(PO(OEt)2), could be observed by 31P NMR spectroscopy. The synthetic and kinetic studies on the cross-coupling reaction of diethyl H-phosphonate with phenyl halides permitted us to elucidate a crucial catalytic role of an acetate group in PdII complexes and to propose two distinctive catalytic cycles, which complemented traditional Pd0/PdII schemes, for the palladium-mediated C−P bond formation.

  • 39.
    Kalek, Marcin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ziadi, Asraa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Stawinski, Jacek
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Microwave-assisted palladium-catalyzed cross-coupling of aryl and vinyl halides with H-phosphonate diesters2008In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 10, no 20, p. 4637-4640Article in journal (Refereed)
    Abstract [en]

    A general and efficient method for the microwave-assisted formation of the C−P bond was developed. Using a prevalent palladium catalyst, Pd(PPh3)4, a quantitative cross-coupling of various H-phosphonate diesters with aryl and vinyl halides was achieved in less than 10 min. The reactions occurred with retention of configuration at the phosphorus center and in the vinyl moiety. Using this protocol, several C-phosphonates, including those bearing nucleoside and cholesteryl moieties, were prepared in high yields.

  • 40.
    Karimi, Farhad
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Erlandsson, Maria
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Lindhe, Örjan
    Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II. Endokrin tumörbiologi.
    Långström, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Synthesis of 11C-labelled metomidate analogues as adrenocortical imaging agents2008In: J. Label Compd Radiopharm, no 51, p. 273-276Article in journal (Refereed)
  • 41.
    Karlsson, Björn
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    O'Mahony, John
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Karlsson, Jesper G
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Bengtsson, Helen
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Eriksson, Leif A
    Nicholls, Ian Alan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Structure and dynamics of monomer-template complexation: an explanation for molecularly imprinted polymer recognition site heterogeneity2008Conference paper (Other academic)
  • 42.
    Karlsson, Erik A.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mechanism of the palladium-catalyzed carbohydroxylation of allene-substituted conjugated dienes: rationalization of the recently observed nucleophilic attack by water on a (pi-allyl)palladium intermediate2008In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 14, no 30, p. 9175-9180Article in journal (Refereed)
    Abstract [en]

    The mechanism of the palladium-catalyzed oxidative carbohydroxylation of allene-substituted 1,3-cyclohexadiene was studied by DFT calculations. All intermediates and transition states of the reaction were identified and their structures were calculated. The calculations confirm the mechanism previously proposed and show that the CC bond-forming step occurs via insertion of one of the double bonds of 1,3-cyclohexadiene into a Pdvinyl bond of a vinylpalladium intermediate. This reaction leads to a (π-allyl)palladium intermediate, and coordination of benzoquinone and a double bond in the molecule to Pd creates a highly reactive cationic π-allyl complex, which is readily attacked by water according to the calculations.

  • 43.
    Kaukoranta, Päivi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Engman, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Hedberg, Christian
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Iridium Catalysts with Chiral Imidazole-Phosphine Ligands for Asymmetric Hydrogenation of Vinyl Fluorides and other Olefins2008In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 350, no 7-8, p. 1168-1176Article in journal (Refereed)
    Abstract [en]

    New chiral bidentate imidazole-phosphine ligands have been prepared and evaluated for the iridium-catalysed asymmetric hydrogenation of olefins. The imidazole-phosphine-ligated iridium catalysts hydrogenated trisubstituted olefins with the same sense of enantiodiscrimination as known iridium catalysts possessing oxazole and thiazole as N-donors. The imidazole-based catalysts were shown to hydrogenate vinyl fluorides, in some cases with the highest ee values published to date.

  • 44. Koshino, Masanori
    et al.
    Solin, Niclas
    Tanaka, Takatsugu
    Isobe, Hiroyuki
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Nakamura, Eiichi
    Imaging the passage of a single hydrocarbon chain through a nanopore2008In: Nature Nanotechnology, ISSN 1748-3387, E-ISSN 1748-3395, Vol. 3, no 10, p. 595-597Article in journal (Refereed)
    Abstract [en]

    Molecular transport through nanoscale pores in films, membranes and wall structures is of fundamental importance in a number of physical, chemical and biological processes(1-6). However, there is a lack of experimental methods that can obtain information on the structure and orientation of the molecules as they pass through the pore, and their interactions with the pore during passage. Imaging with a transmission electron microscope is a powerful method for studying structural changes in single molecules as they move(7,8) and for imaging molecules confined inside carbon nanotubes(9). Here, we report that such imaging can be used to observe the structure and orientation of a hydrocarbon chain as it passes through nanoscale defects in the walls of a single-walled carbon nanotube to the vacuum outside, and also to study the interactions between the chain and the nanopore. Based on experiments at 293 K and 4 K we conclude that the major energy source for the molecular motions observed at 4 K is the electron beam used for the imaging.

  • 45.
    Kännaste, Astrid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Volatiles of Conifer Seedlings: Compositions and Resistance Markers2008Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Pine weevils cause major damage to newly planted conifer seedlings in reforestation areas. However, recent findings indicate that small (“mini”) seedlings, planted at the age of 7-10 weeks, are gnawed less by pine weevils than the larger, conventionally planted seedlings. Thus, it has been proposed that planting young conifer seedlings in clear-cut areas may reduce the damage caused by pine weevils. In attempts to determine why mini seedlings appear to be less damaged by pine weevils than “conventional” seedlings, the volatiles released by Norway spruce and Scots pine mini seedlings were investigated, since such chemicals are of great importance in herbivore-plant communication, inter alia acting as repellents, attractants or antifeedants.

    Volatiles from the seedlings were collected, separated and identified by solid phase microextraction (SPME) followed by gas chromatography-mass spectrometry.

    The results show that there are high levels of chemodiversity among both spruce and pine seedlings. Between-tissue and age-related variations in their emissions were also found.

    Norway spruce clones infested by mites were also examined to assess genotype- and pest-specific stress reactions of Norway spruce. Finally, the effects of certain spruce defense compounds on the behavior of the large pine weevil Hylobius abietis were examined.

  • 46.
    Kännaste, Astrid
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Vongvanich, Namphung
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Borg-Karlson, Anna-Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Infestation by a Nalepella species induces emissions of alpha- and beta-farnesenes, (-)- linalool and aromatic compounds in Norway spruce clones of different susceptibility to the large pine weevil2008In: Arthropod-Plant Interactions, ISSN 1872-8855, Vol. 2, no 1, p. 31-41Article in journal (Refereed)
    Abstract [en]

    The emissions of spruce grafts (Picea abies), caused by infestation of an acarid species of the genus Nalepella were investigated. Volatiles of three clones, both healthy and infested, with different susceptibility to the large pine weevil Hylobius abietis were collected by solid phase micro extraction (SPME) and analyzed by gas chromatograph coupled to mass-spectrometry (GC-MS). In addition, enantiomers of the main chiral compounds were separated by a two dimensional-gas chromatograph (2D-GC). In the characteristic flower-like fragrances emitted by the infested grafts large amounts of E-beta-farnesene, E, E-alpha-farnesene, (-)-linalool, methyl salicylate and minute amounts of benzyl alcohol, E-anethole, methyl benzoate, neral and geranial were found. All together, these compounds could explain the characteristic scent emitted by the infested seedlings. Large differences in the emissions of E-beta-farnesene, E, E-alpha-farnesene and methyl salicylate were found between but not within the clones.

  • 47.
    Larsson, Rikard
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Dynamic Systems for Screening, Control and Identification of Protein-Ligand Interactions2008Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Dynamic systems for screening, control and identification of different protein-ligand interactions are presented. Dynamic chemistry is used to produce new compounds/constituents in situ that can interact with a target molecule. Several entities can be introduced at the same time and interact with one another. These molecules make a dynamic combinatorial library (DCL) which is used in dynamic combinatorial chemistry (DCC). DCC is a recently introduced approach to generate dynamically interchanging libraries of compounds. These libraries are made of different building blocks that reversibly interact with one another and spontaneously assemble to encompass all possible combinations. If a target molecule, for instance a receptor is added to the system and one or more molecules show affinity to the target species, these compounds will, according to Le Châtelier´s principle, be amplified on the expense of the other non-bonding constituents. To further advance the technique, especially when biological systems are targeted, new reaction types and new screening methods are necessary. This thesis describes the development of different reversible reactions, thiol/disulfide interchange, transthiolesterification and the nitroaldol (Henry) reaction as means of generating reversible covalent bond reactions. Two different types of target proteins are used, enzymes belonging to the hydrolase family and the plant lectin Concanavalin A.

    Dynamic combinatorial resolution (DCR) is presented. This new concept relies on the consecutive kinetic resolution of dynamic combinatorial libraries, leading to complete amplification and control of dynamically interchangeable processes. By applying a kinetically controlled step to a thermodynamically controlled system, complete transformation and amplification can be obtained. The concept has been demonstrated by developing transthiolesterification and nitroaldol exchange reactions to generate diversity, forming libraries under thermodynamic control, and used in one-pot processes with kinetically controlled enzyme-mediated resolution. The results demonstrate that the reaction types are useful for the generation of dynamic libraries, and that the dynamic combinatorial resolution concept is highly valuable for efficient substrate identification, asymmetric synthesis, and library screening.

    The thesis also describes three other dynamic chemistry protocols. The first one describes dynamic kinetic resolution (DKR) of nitroaldol adducts by combined lipase catalysis. The second one describes finding lectin inhibitors from a glycodisulfide library and the third one describes finding an inhibitor of acetylcholinesterase using a tandem driven dynamic self-inhibition approach.

  • 48.
    Leijondahl, Karin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis and asymmetric transformations of diols by enzyme- and ruthenium catalysis2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The major part of this thesis describes the synthesis of aliphatic secondary diols and the development of lipase- and ruthenium-catalyzed asymmetric transformations of these diols.

    Several acyclic 1,4-diols and 1,5-diols were synthesized, and by combining a lipase-catalyzed asymmetric transformation with a ruthenium-catalyzed epimerization, enantiomerically- and diastereomerically enriched diacetates were obtained. The scope and limitations of the system were also investigated, and some problems were encountered with electron-deficient diols. The diacetate products were further transformed into natural product heterocycles and chiral ligands.

    A thorough study of the enzyme-catalyzed asymmetric transformation of 1,3-cyclohexanediol was also performed. It was found that there was a difference in the enzyme selectivity for the cis- and trans- diols, respectively, and while poor selectivity was observed for the trans-diol, cis-1,3-cyclohexanediol could be efficiently desymmetrized. By adding different epimerization catalysts, both cis- and trans-1,3-cyclohexanediol could be obtained in high enantio- and diastereoselectivities.

    The use of hydrogen transfer for the reduction of cyclic 1,3-diketones was also demonstrated, and the reactions could in many cases be carried out in a microwave oven.

  • 49.
    Leijondahl, Karin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Borén, Linnéa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Braun, Roland
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Enantiopure 1,5-diols from dynamic kinetic asymmetric transformation: Useful synthetic intermediates for the preparation of chiral heterocycles2008Conference paper (Other academic)
  • 50.
    Leijondahl, Karin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Borén, Linnéa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Braun, Roland
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Enantiopure 1,5-diols from dynamic kinetic asymmetric transformation: Useful synthetic intermediates for the preparation of heterocycles2008In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 10, no 10, p. 2027-2030Article in journal (Refereed)
    Abstract [en]

    Dynamic kinetic asymmetric transformation (DYKAT) of a series of 1,5-diols has been performed in the presence of Candida antarctica lipase B (CALB), Pseudomonas cepacia lipase H (PS-C II), and ruthenium catalyst 4. The resulting optically pure 1,5-diacetates are useful synthetic intermediates, which was demonstrated by the syntheses of both an enantiopure 2,6-disubstituted piperidine and an enantiopure 3,5-disubstituted morpholine.

12 1 - 50 of 91
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