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  • 151.
    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.

  • 152.
    Angelin, Marcus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Larsson, Rikard
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Vongvilai, Pornrapee
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Ramström, Olof
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Introducing Dynamic Combinatorial Chemistry: Probing the Substrate Selectivity of Acetylcholinesterase2010In: Journal of Chemical Education, ISSN 0021-9584, E-ISSN 1938-1328, Vol. 87, no 11, p. 1248-1251Article in journal (Refereed)
  • 153.
    Angelin, Marcus
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Rahm, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Fischer, Andreas
    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.
    Diastereoselective One-Pot Tandem Synthesis of 3-Substituted Isoindolinones: A Mechanistic Investigation2010In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 75, no 17, p. 5882-5887Article in journal (Refereed)
    Abstract [en]

    The mechanism of a base-catalyzed one-pot reaction of 2-cyanobenzaldehyde and primary nitroalkanes, to produce 3-substituted isoindolinones, has been investigated. A route starting with a nitroaldol (Henry) reaction, followed by a subsequent cyclization and rearrangement, was supported by intermediate analogue synthesis and DFT calculations. Direct diastereoselective crystallization from the reaction mixture was also achieved and studied for a number of substrates. Furthermore, the 3-substituted isoindolinones are an interesting group of compounds, both present important natural products, as well as being precursors to other valuable building blocks.

  • 154.
    Angles d'Ortoli, Thibault
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Assembling and Unraveling Carbohydrates Structures: Conformational analysis of synthesized branched oligosaccharides2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Advances in the elaboration of vaccines and enzyme inhibitors rely on acquiring more knowledge about protein-carbohydrate binding events. Furthermore, the relationships between biological function and the three-dimensional properties of large glycans can be studied by focusing on the structural components they contained, namely, by scaling down the system under analysis. Chemical methods are useful assets as they allow the isolation and determination of epitopes; these small and recognizable fragments that lead to very specific interactions. In this thesis, biologically relevant saccharides were obtained using recently developed concepts in carbohydrate synthesis and NMR spectroscopy was used to unravel their conformational preferences.

    In paper I, the convergent synthesis of the tetrasaccharide found in the natural product solaradixine is described. Reactivity enhanced disaccharide glycosyl donors were coupled to a disaccharide acceptor in a 2 + 2 fashion. The computer program CASPER was subsequently used to verify the synthesized structure.

    The conformation arming concept employed in paper I was further investigated in paper II. An NMR-based methodology enabled the determination of the ring conformations of a set of donors. Subsequently, glycosylation reactions were performed and yields were correlated to donors ring shapes. Perturbations in the rings shape caused by bulky silyl ether protective groups were sufficient to boost the potency of several donors. As a matter of fact, complex branched oligosaccharides could be obtained in good to excellent yields.

    In paper III, NMR spectroscopy observables were measured to elucidate the ring shape, the mutual orientation of the rings across the glycosidic bond and the positions of the side chains of 5 trisaccharides found in larger structures. With the aid of molecular dynamics simulations, their overall conformational propensities were revealed.

    Finally, the software CASPER prediction skills were improved by adding, inter alia, NMR information of synthesized mono- and disaccharides to its database. Unassigned chemical shifts from polysaccharides served as input to challenge its ability to solve large carbohydrate structures.

  • 155.
    Angles d'Ortoli, Thibault
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hamark, Christoffer
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Structure-Reactivity Relationships of Conformationally Armed Disaccharide Donors and Their Use in the Synthesis of a Hexasaccharide Related to the Capsular Polysaccharide from Streptococcus pneumoniae Type 372017In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 82, no 15, p. 8123-8140Article in journal (Refereed)
    Abstract [en]

    To advance the field of glycobiology, efficient synthesis methods of oligosaccharides and glycoconjugates are a requisite. In glycosylation reactions using superarmed donors, both selectivity and reactivity issues must be considered, and we herein investigate these aspects for differently protected beta-linked 2-O-glycosylated glucosyl donors carrying bulky tert-butyldimethylsilyl groups to different extents. The acceptors in reactions being secondary alcohols presents a challenging situation with respect to steric crowding. Conformational pyranose ring equilibria of the superarmed disaccharide donors with axial-rich substituents contained skew and boat conformations, and three-state models were generally assumed. With NIS/TfOH as the promotor, 2,6-di-tert-butyl-4-methylpyridine as the base, and a dichloromethane/toluene solvent mixture, ethyl 1-thio-beta-d-glucosyl disaccharide donors having 6-O-benzyl group(s) besides tert-butyldimethylsilyl groups were efficiently coupled at -40 degrees C to the hydroxyl group at position 3 of glucopyranosyl acceptors to form beta-(1 -> 2),beta-(1 -> 3)-linked trisaccharides, isolated in excellent 95% yield. The more axial-rich donors in skew and boat conformations are thus preorganized closer to the assumed transition state in these glycosylation reactions. The developed methodology was subsequently applied in the synthesis of a multibranched hexasaccharide related to the capsular polysaccharide from Streptococcus pneumoniae type 37, which consists of a beta-(1 -> 3)-linked backbone and a beta-(1 -> 2)-linked side chain of D-glucosyl residues in disaccharide repeating units.

  • 156.
    Angles d'Ortoli, Thibault
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mobarak, Hani
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Ståhle, Jonas
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hamark, Christoffer
    Fontana, Carolina
    Engström, Olof
    Apostolica, Patricia
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Complete 1H and 13C NMR chemical shift assignments of mono- to tetrasaccharides as basis for NMR chemical shift predictions of oligo- and polysaccharides using the computer program CASPERManuscript (preprint) (Other academic)
  • 157.
    Angles d'Ortoli, Thibault
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sjöberg, Nils A.
    Vasiljeva, Polina
    Lindman, Jonas
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bergenstråhle-Wohlert, Malin
    Wohlert, Jakob
    Temperature Dependence of Hydroxymethyl Group Rotamer Populations in Cellooligomers2015In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 119, no 30, p. 9559-9570Article in journal (Refereed)
    Abstract [en]

    Empirical force fields for computer simulations of carbohydrates are often implicitly assumed to be valid also at temperatures different from room temperature for which they were optimited: Herein, the temperature dependence of the hydroxymethyl group rotamer populations in short oligogaccharides is invegtigated using Molecular dynamics simulations and NMR spectroscopy. Two oligosaccharides, methyl beta-cellobioside and beta-cellotetraose were simulated using three different carbohydrate force fields (CHARMM C35, GLYCAM06, and GROMOS 56A(carbo)) in combination with different water models (SPC, SPC/E, and TIP3P) using replica exchange molecular dynamics simulations. For comparison, hydroxymethyl group rotamer populations were investigated for methyl beta-cellobioside and cellopentaose based- on measured NMR (3)J(H5,H6) coupling constants, in the latter case by using a chemical shift selective NMR-filter. Molecular dynamics simulations in combination with NMR spectroscopy show that the temperature dependence of the hydroxymethyl rotamer population in these short cellooligomers, in the range 263-344 K, generally becomes exaggerated in simulations when compared to experimental data, but also that it is dependent on simulation conditions, and most notably properties of the water model.

  • 158.
    Angles d'Ortoli, Thibault
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of the tetrasaccharide glycoside moiety of Solaradixine and rapid NMR-based structure verification using the program CASPER2016In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 72, no 7, p. 912-927Article in journal (Refereed)
    Abstract [en]

    The major glycoalkaloid in the roots of Solanum laciniatum is Solaradixine having the branched tetrasaccharide beta-D-Glcp-(1 -> 2)-beta-D-Glcp-(1 -> 3)[alpha-L-Rhap-(1 -> 2)]-beta-D-Galp linked to O3 of the steroidal alkaloid Solasodine. We herein describe the synthesis of the methyl glycoside of the tetrasaccharide using a super-armed disaccharide as a donor molecule. A 2-(naphthyl)methyl protecting group was used in the synthesis of the donor since it was tolerant to a wide range of reaction conditions. The 6-O-benzylated-hexa-O-tert-butyldimethylsilyi-protected beta-D-Glcp-(1 -> 2)-beta-D-Glcp-SEt donor, which avoided 1,6-anydro formation, was successfully glycosylated at O3 of a galactoside acceptor molecule. However, subsequent glycosylation at O2 by a rhamnosyl donor was unsuccessful and instead a suitably protected alpha-L-Rhap(1 -> 2)-beta-D-Galp-OMe disaccharide was used as the acceptor molecule together with a super-armed beta-D-Glcp-(1 -> 2)-beta-D-Glcp-SEt donor in the glycosylation reaction, to give a tetrasaccharide in a yield of 55%, which after deprotection resulted in the target molecule, the structure of which was verified by the NMR chemical shift prediction program CASPER.

  • 159.
    Ankarloo, Jonas
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Wikman, Susanne
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Nicholls, Ian A.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Escherichia coli mar and acrAB Mutants Display No Tolerance to Simple Alcohols2010In: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 11, no 4, p. 1403-1412Article in journal (Refereed)
    Abstract [en]

    The inducible Mar phenotype of Escherichia coli is associated with increased tolerance to multiple hydrophobic antibiotics as well as some highly hydrophobic organic solvents such as cyclohexane, mediated mainly through the AcrAB/TolC efflux system. The influence of water miscible alcohols ethanol and 1-propanol on a Mar constitutive mutant and a mar deletion mutant of E. coli K-12, as well as the corresponding strains carrying the additional acrAB deletion, was investigated. In contrast to hydrophobic solvents, all strains were killed in exponential phase by 1-propanol and ethanol at rates comparable to the parent strain. Thus, the Mar phenotype does not protect E. coli from killing by these more polar solvents. Surprisingly, AcrAB does not contribute to an increased alcohol tolerance. In addition, sodium salicylate, at concentrations known to induce the mar operon, was unable to increase 1-propanol or ethanol tolerance. Rather, the toxicity of both solvents was increased in the presence of sodium salicylate. Collectively, the results imply that the resilience of E. coli to water miscible alcohols, in contrast to more hydrophobic solvents, does not depend upon the AcrAB/TolC efflux system, and suggests a lower limit for substrate molecular size and functionality. Implications for the application of microbiological systems in environments containing high contents of water miscible organic solvents, e. g., phage display screening, are discussed.

  • 160.
    Ankerfors, M.
    et al.
    RISE, Innventia.
    Duker, E.
    Lindström, T.
    RISE, Innventia.
    Topo-chemical modification of fibres by grafting of carboxymethyl cellulose in pilot scale2013In: Nordic Pulp and Paper Research Journal, ISSN 0283-2631 , no 1, p. 6-14Article in journal (Refereed)
  • 161.
    Ansari, Farhan
    KTH.
    Cellulose fibers reinforced thermoset composites - micro vs nano2016In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Article in journal (Other academic)
  • 162.
    Antoni G., Amschler H., Zech K., Långström B.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Synthesis of [18F]labelled roflumilast using difluoro[18F]bromo methane as alkylating agent2001In: Synthesis and Applications of Isotopically LabelledArticle in journal (Refereed)
  • 163.
    Antoni G., Ögren M., Långström B.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Enzymes as catalysts in labelling synthesis using short-lived radionuclides2001In: Synthesis and Applications of Isotopically LabelledArticle in journal (Refereed)
  • 164.
    Antoni, Gunnar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Kihlberg, T.
    Långström, B.
    11C: Labelling chemistry and labelled compounds2003In: Handbook Chem03_0302, 2003, no 332, p. 119-165Chapter in book (Refereed)
  • 165.
    Antoni, Gunnar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Långström, Bengt
    Asymmetric synthesis of L-2-amino[3-11C]butyric acid, L-[3-11C]norvaline and L-[3-11C]valine.1987In: Acta Chemica Scandinavica, ISSN 0904-213X, E-ISSN 1902-3103, Vol. B41, p. 511-Article in journal (Refereed)
  • 166.
    Antoni, Gunnar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Långström, Bengt
    Synthesis of DL-11C-labelled alanine, 2-aminobutyric acid, norvaline, leucine and phenylalanine and preparation of L-[3-11C]alanine and L-[3-11C]phenylalanine.1987In: Journal of labelled compounds & radiopharmaceuticals, ISSN ISSN 0362-4803, EISSN 1099-1344, Vol. 24, p. 125-Article in journal (Refereed)
  • 167.
    Antoni, Gunnar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Långström, Bengt
    Synthesis of DL-[3-11C]valine using [2-11C]isopropyl iodide and preparation of L-[3-11C]valine by treatment with D-amino acid oxidase.1987In: Int. J. Appl. Radiat. Isot., Vol. 38, p. 655-Article in journal (Refereed)
  • 168.
    Antoni, Gunnar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Långström, Bengt
    Synthesis of gamma-amino[4-11C]butyric acid.1989In: Journal of labelled compounds & radiopharmaceuticals, ISSN 0362-4803, E-ISSN 1099-1344, Vol. 27, p. 571-Article in journal (Refereed)
  • 169.
    Antoni, Gunnar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Ulin, Johan
    Långström, Bengt
    Synthesis of the 11C-labelled b-adrenargic receptor ligands atenolol, metoprolol and propranol.1989In: The international journal of applied radiation and isotopes, ISSN 0020-708X, E-ISSN 1878-1284, Vol. 40, p. 561-Article in journal (Refereed)
  • 170.
    Antonsson, Cecilia
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Mjölk, gluten och ADHD: En litteraturundersökning om mjölk och glutens påverkan hos barn med ADHD2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Attention Deficit Hyperactivity Disorder (ADHD) is becoming a more common diagnosis of younger children. In recent years the perception that some ingredients in our food may have a negative effect regarding the symptoms in children with ADHD has grown stronger. Children with ADHD often suffer from irritated bowel syndromes which affect their ability to digest food. This may result in malnutrition as well as a release of substances that are harmful.The purpose of this report is to compile and illustrate the knowledge of how special food, particular milk protein and gluten, may affect the symptoms of children with ADHD. Also, the report aims to evaluate if there should be changes made in Kindergarten to increase the well-being of these children. The report is a summary of research results on the effects milk protein and gluten have on children with ADHD.The majority of children with ADHD demonstrate decreased symptoms if they receive a diet without milk protein and gluten.If children with ADHD would be given a special diet excluding milk protein and gluten it is realistic to assume that their ADHD-symptoms might be reduced with a greater sense of well-being and quality of life as a result.

  • 171.
    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.

  • 172.
    Arafa, Wael A. A.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kärkäs, Markus D.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Lee, Bao-Lin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Åkermark, Torbjörn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Liao, Rong-Zhen
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Berends, Hans-Martin
    Messinger, Johannes
    Siegbahn, Per E. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Dinuclear manganese complexes for water oxidation: evaluation of electronic effects and catalytic activity2014In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 24, p. 11950-11964Article in journal (Refereed)
    Abstract [en]

    During recent years significant progress has been made towards the realization of a sustainable and carbon-neutral energy economy. One promising approach is photochemical splitting of H2O into O-2 and solar fuels, such as H-2. However, the bottleneck in such artificial photosynthetic schemes is the H2O oxidation half reaction where more efficient catalysts are required that lower the kinetic barrier for this process. In particular catalysts based on earth-abundant metals are highly attractive compared to catalysts comprised of noble metals. We have now synthesized a library of dinuclear Mn-2 (II,III) catalysts for H2O oxidation and studied how the incorporation of different substituents affected the electronics and catalytic efficiency. It was found that the incorporation of a distal carboxyl group into the ligand scaffold resulted in a catalyst with increased catalytic activity, most likely because of the fact that the distal group is able to promote proton-coupled electron transfer (PCET) from the high-valent Mn species, thus facilitating O-O bond formation.

  • 173. Arafa, Wael A. A.
    et al.
    Mohamed, Ashraf M.
    Abdel-Magied, Ahmed F.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    ULTRASOUND-MEDIATED THREE-COMPONENT REACTION ON-WATER PROTOCOL FOR THE SYNTHESIS OF NOVEL MONO- AND BIS-1,3-THIAZIN-4-ONE DERIVATIVES2017In: Heterocycles, ISSN 0385-5414, E-ISSN 1881-0942, Vol. 94, no 8, p. 1439-1455Article in journal (Refereed)
    Abstract [en]

    Green synthetic and catalyst-free strategy towards the synthesis of novel mono- and bis-1,3-thiazin-4-one scaffolds through a one pot, reaction of carbon disulfide, monoacetylenic esters and amines under ultrasonication has been reported. The merits of this protocol comprise no need for tedious workup steps and afforded the desired products in excellent yields make this synthetic protocol more efficient and worthy of further attentiveness. Moreover, the method exhibited excellent score in a number of green metrics.

  • 174. Arafa, Wael Abdelgayed Ahmed
    et al.
    Abdel-Magied, Ahmed Fawzy
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Nuclear Material Authority, Egypt.
    Utilization of ultrasonic irradiation as green and effective one-pot protocol to prepare a novel series of bis-2-amino-1,3,4-oxa(thia) diazoles and bis-tetrazoles2017In: ARKIVOC, ISSN 1551-7004, E-ISSN 1551-7012, p. 327-340Article in journal (Refereed)
    Abstract [en]

    In an effective and straightforward conversion, bis-semicarbazones and bis-thiosemicarbazones are transformed into a diversity of novel substituted bis-2-amino-1,3,4-oxadiazoles and bis-2-amino-1,3,4-thiadiazoles, respectively under ultrasonic irradiation. Bis-tetrazoles are obtained from the dialdehydes by sequential reaction with hydroxylamine hydrochloride, phosphorus pentoxide and sodium azide without isolation of the intermediates oximes and nitriles. All the reactions proceed cleanly and smoothly under mild conditions, with short reaction times and broad functional groups possibility. No side reactions were observed. [GRAPHICS]

  • 175.
    Arefalk, Anna
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Pharmacy, Department of Medicinal Chemistry.
    New Methods for the Synthesis of 3-Substituted 1-Indanones: A Palladium-Catalyzed Approach2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In medicinal chemistry, there is a constant need for new preparative methods, both to make the synthesis process more effective, and to increase the accessibility to a wide variety of compounds. A number of different approaches can be used to attain these goals. Transition metal catalysis is generally performed under mild conditions, providing both regio- and chemoselective reactions. Thus, it offers an attractive means of preparation of complex drug candidates. Two additional methodologies used to increase the preparative efficiency are one-pot protocols and controlled microwave heating. One-pot and multi-component reactions are less time consuming than step-by-step reactions, and microwave heating has been used to considerably shorten the reaction times.

    This thesis describes a new palladium-catalyzed, one-pot reaction producing racemic acetal-protected 3-hydroxy-1-indanones from ethylene glycol vinyl ether and triflates of salicylic aldehydes. The triflates were prepared using controlled microwave heating. The reaction sequence starts with a regioselective internal Heck coupling, followed by an annulation cascade. By including secondary amines in the reaction mixture, the reaction was further developed into a three-component reaction delivering racemic acetal-protected 3-amino-1-indanones. This new method was utilized for the synthesis of primary, secondary and tertiary aminoindanones. Finally, by using enantiopure t-butyl sulfinyl imines, derived from salicylic aldehyde triflates and ethylene glycol vinyl ether as starting materials in a closely related type of palladium coupling–annulation sequence, a stereoselective protocol providing enantiomerically pure 3-amino-1-indanones was developed. To demonstrate an application in medicinal chemistry, the enantiopure 3-amino-1-indanones were incorporated as P2 and/or P2´ substituents into active HIV-1 protease inhibitors.

  • 176.
    Arja, Katriann
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Multimodal Porphyrin-Based Conjugates: Synthesis and characterization for applications as amyloid ligands, photodynamic therapy agents and chiroptical materials2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Organic compounds that interact both with certain biological targets and display specific photophysical properties can be utilized as molecular tools to visualize and possibly effect disease related processes taking place in living organisms. In this regard, porphyrins are a class of naturally occurring molecules that possess intriguingly interesting photophysical properties where they can act as luminescent probes by emitting detectable light, as well as photosensitizers in the light mediated therapy called photodynamic therapy. In this thesis, the porphyrin structure has been synthetically combined with other molecule classes to achieve compounds with desirable multimodal characteristics.

    Firstly, luminescent conjugated oligothiophenes (LCOs) that have extensively, and with great success, been utilized as fluorescent ligands for amyloid formations, have been conjugated to porphyrins to render oligothiophene porphyrin hybrids (OTPHs) comprising two optically active modalities. When applied as fluorescent amyloidophilic dyes for visualization of amyloid-β (Aβ), one of the pathological hallmarks in Alzheimer’s disease, an enhanced optical assignment of distinct aggregated forms of Aβ was afforded.  Thus, properly functionalized OTPHs could give us more information about pathological processes underlying devastating disorders, such as Alzheimer’s disease. In addition, the OTPHs can be associated with synthetic peptides inducing peptide folding into certain three-dimensional helical structures giving rise to novel optically active materials.

    Secondly, this thesis also embraces porphyrins’ potential as photosensitizers in photodynamic therapy to kill cancer cells. Grounded on the prerequisites for an optimal photosensitizer, we designed porphyrin-based conjugates equipped with common carbohydrates for improved cancer cell selectivity and with a fluorinated glucose derivative, 2-fluoro 2-deoxy glucose, for advantageous metabolism in cancer cells. Furthermore, incorporation of a radioisotopic fluorine-18 atom into the glycoporphyrins could give the means for diagnostic use of the conjugates in positron emission tomography (PET).

    In order to tether together the above-mentioned molecular moieties in a controlled fashion, we developed a robust synthetic strategy for asymmetrical functionalization of porphyrin core. The method involves chlorosulfonation of this otherwise inert tetrapyrrolic structure, followed by alkynylation. Parallelly to amide coupling reactions, copper(I)-catalyzed alkyne azide cycloaddition is used for fast and high-yielding late-stage conjugations. Overall, this thesis demonstrates how combining different molecular moieties in synthetic organic chemistry yields novel molecules with combined and improved multimodal properties for biological and medicinal applications, guided by the design-by-function methodology.      

  • 177.
    Arkhypchuk, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Novel Approaches to Phosphorus-containing Heterocycles and Cumulenes2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Fast development in all areas of life and science over the last 50 years demands versatile, energy efficient and cheap materials with specific but easily tuneable properties which can be used for example in organic light emitting diodes (OLEDs), thin-film transistors, photovoltaic cells, etc. This thesis is devoted to the development of novel synthetic approaches to molecules with potential applications in the field of molecular electronics.  The acquisition of a detailed mechanistic understanding of the newly developed reactions is central to the work presented in this thesis.

    The first chapter is dedicated to the development of a new procedure for the preparation of phospha-Wittig-Horner (pWH) reagents, i.e. a reagents that has been known to convert carbonyl compounds into compounds with P=C double bonds. Each step of the synthetic sequence, i.e. preparation of the starting P,P-dichlorophosphines, their phosphorylation using the Michaelis-Arbuzov protocol, coordination to the metal centre and final hydrolysis, are presented in detail. A possible route to uncoordinated pWH reagents is also discussed.

    The second chapter focuses on the reactivity of the pWH reagents with acetone under different reaction conditions. The results show how changes in the ratio of starting material vs. base as well as reaction time or structure of the pWH reagent can influence the reaction outcome and the stability of the obtained products. The possibility to prepare unusual phosphaalkenes with unsaturated P-substituents is presented.

    The third chapter of the thesis is dedicated to the reactivity of pWH reagents towards symmetric and asymmetric ketones which contain one or two acetylene units. The proposed mechanisms of the reactions are studied by means of in situ FTIR spectroscopy as well as theoretical calculations. Physical-chemical properties of oxaphospholes, cumulenes and bisphospholes are presented.

    The last chapter is dedicated to reactivity studies of pWH reagents towards ketenes, and the exploration of a reliable route to 1-phosphaallenes. Detailed mechanistic studies of the pWH reaction that are based on the isolation and crystallographic characterization of unique reaction intermediates are presented. The reactivity of phosphaallenes towards nucleophiles such as water and methanol are examined.

    In summary, this thesis presents synthetic routes to novel phosphorus-containing molecules, together with detailed studies of the reaction mechanisms of the observed transformations.

  • 178.
    Arkhypchuk, Anna I.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    D'Imperio, Nicolas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    One-Pot Intermolecular Reductive Cross-Coupling of Deactivated Aldehydes to Unsymmetrically 1,2-Disubstituted Alkenes2018In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 20, no 17, p. 5086-5089Article in journal (Refereed)
    Abstract [en]

    The phospha-Peterson reaction between a lithiated secondary phosphane, MesP(Li)TMS, and an aldehyde affords Mes-phosphaalkenes which, upon methanol addition and P-oxidation, react with a second carbonyl compound site specifically to produce unsymmetric alkenes. The E/Z selectivity of the one-pot cross coupling is largely determined by the electronic nature of the aryl substituent of the first aldehyde, with electron-donating groups giving rise to increased amounts of Z-alkenes.

  • 179.
    Arkhypchuk, Anna I.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    D'Imperio, Nicolas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Triarylalkenes from the site-selective reductive cross-coupling of benzophenones and aldehydes2019In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 55, no 43, p. 6030-6033Article in journal (Refereed)
    Abstract [en]

    PhP(Li)TMS converts benzophenones to phosphaalkenes which upon activation under oxidizing, basic conditions react with aromatic aldehydes under the formation of triarylalkenes. The one-pot reaction omits transition metals, proceeds at room temperature and precludes the formation of any homo-coupling products. Systematic substrate variations reveal reactivity patterns that are useful for the identification of ketone/aldehyde combinations that can be coupled in yields up to 80%.

  • 180.
    Arkhypchuk, Anna I.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Kovacs, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Isolation and Characterization of a Monoprotonated Hydroporphyrin2018In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 48, p. 7051-7056Article in journal (Refereed)
    Abstract [en]

    A simple protocol for the controlled preparation of mono- and diprotonated hydroporphyrins (chlorins) is presented. The chlorins carried 10-aryl groups with electron-neutral (phenyl), electron-donating (p-OMe-C6H4) or electron-withdrawing (pentafluorophenyl) substituents. The protonation reactions were readily followed by UV/Vis absorption spectroscopy, enabling the determination of the first (4.8-5.3) and second pK(a)'s (1.7-0.5). Both mono- and diprotonated species were fully characterized by H-1 NMR spectroscopy, which, in combination with theoretical studies, showed that these macrocycles were significantly distorted in solution. A 10-phenyl-substituted monoprotonated chlorin was characterized by X-ray crystallography. This is the first structurally characterized hydroporphyrin monocation, and the first crystal structure of a sterically unencumbered singly protonated tetrapyrrole. The photostabilities of the mono- and diprotonated 10-phenylchlorins were measured upon irradiation into their Soret bands; protonation yielded increased photostabilities.

  • 181.
    Arkhypchuk, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Mihali, Viorica Alina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Ehlers, Andreas
    VU University Amsterdam.
    Lammertsma, Koop
    VU University Amsterdam.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Phosphorus Heterocylces from Phosphinophosphonates and α,β-Unsaturated KetonesManuscript (preprint) (Other academic)
  • 182.
    Arkhypchuk, Anna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Svyaschenko, Yurii
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Mechanism of the Phospha-Wittig-Horner Reaction2013In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 52, no 25, p. 6484-6487Article in journal (Refereed)
  • 183. Aronsson, Per
    et al.
    Munissi, Joan J E
    Gruhonjic, Amra
    Fitzpatrick, Paul A
    Landberg, Göran
    Nyandoro, Stephen S
    Erdelyi, Mate
    Phytoconstituents with Radical Scavenging and Cytotoxic Activities from Diospyros shimbaensis.2016In: Diseases (Basel, Switzerland), ISSN 2079-9721, Vol. 4, no 1, article id E3Article in journal (Refereed)
    Abstract [en]

    As part of our search for natural products having antioxidant and anticancer properties, the phytochemical investigation of Diospyros shimbaensis (Ebenaceae), a plant belonging to a genus widely used in East African traditional medicine, was carried out. From its stem and root barks the new naphthoquinone 8,8'-oxo-biplumbagin (1) was isolated along with the known tetralones trans-isoshinanolone (2) and cis-isoshinanolone (3), and the naphthoquinones plumbagin (4) and 3,3'-biplumbagin (5). Compounds 2, 4, and 5 showed cytotoxicity (IC50 520-82.1 μM) against MDA-MB-231 breast cancer cells. Moderate to low cytotoxicity was observed for the hexane, dichloromethane, and methanol extracts of the root bark (IC50 16.1, 29.7 and > 100 μg/mL, respectively), and for the methanol extract of the stem bark (IC50 59.6 μg/mL). The radical scavenging activity of the isolated constituents (1-5) was evaluated on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The applicability of the crude extracts and of the isolated constituents for controlling degenerative diseases is discussed.

  • 184. Arukuusk, Piret
    et al.
    Pärnaste, Ly
    Hällbrink, Mattias
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Langel, Ülo
    Stockholm University, Faculty of Science, Department of Neurochemistry. Tartu University, Estonia.
    PepFects and NickFects for the Intracellular Delivery of Nucleic Acids2015In: Cell-Penetrating Peptides: Methods and Protocols / [ed] Ülo Langel, New York: Springer, 2015, Vol. 1324, p. 303-315Chapter in book (Refereed)
    Abstract [en]

    Nucleic acids can be utilized in gene therapy to restore, alter, or silence gene functions. In order to reveal the biological activity nucleic acids have to reach their intracellular targets by passing through the plasma membrane, which is impermeable for these large and negatively charged molecules. Cell-penetrating peptides (CPPs) condense nucleic acids into nanoparticles using non-covalent complexation strategy and mediate their delivery into the cell, whereas the physicochemical parameters of the nanoparticles determine the interactions with the membranes, uptake mechanism, and subsequent intracellular fate. The nanoparticles are mostly internalized by endocytosis that leads to the entrapment of them in endosomal vesicles. Therefore design of new CPPs that are applicable for non-covalent complex formation strategy and harness endosomolytic properties is highly vital. Here we demonstrate that PepFects and NickFects are efficient vectors for the intracellular delivery of various nucleic acids.This chapter describes how to form CPP/pDNA nanoparticles, evaluate stable nanoparticles formation, and assess gene delivery efficacy.

  • 185.
    Arvidsson P., Frackenpohl J., Ryder N., Liechty B., Petersen F., Zimmermann H., Camenisch G., Woessner R., Seebach D.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    On the antimicrobial and hemolytic activities of amphiphilic B-peptides.2001In: ChemBioChem, no 2(10), p. 771-773Article in journal (Refereed)
  • 186.
    Arvidsson P., Ruepling M., Seebach D.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry.
    Design, machine synthesis, and NMR-solution structure of a B-heptapeptide forming a saltbridge stabilized 314-helix in methanol and in water2001In: Chemical Communications (Cambridge, U K), p. 649-650Article in journal (Refereed)
  • 187.
    Arvidsson, Per
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Frackenpohl, J
    Seebach, D
    Syntheses an CD-Spectroscopic Investigations of Longer-Chain B-Peptides: Preparation by Solid-Phase Couplings of Single Amino Acids, Dipeptides, and Tripeptides2003In: Helvetica Chemica Acta, no 86, p. 1552-1553Article in journal (Refereed)
  • 188.
    Arvidsson, Per
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Ryder, N
    Weiss, M
    Gross, G
    Kretz, O
    Woessner, R
    Seebach, D
    Antibiotic and Hemolytic Activity of a B2/B3 Peptide Capable of Folding into a 12/10-Helical Secondary Structure2003In: ChemBioChem, no 4, p. 1345-1347Article in journal (Refereed)
  • 189.
    Arvidsson, Per
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Organisk kemi.
    Ryder, Neil S.
    Weiss, H. Markus
    Hook, David F.
    Escalante, Jaime
    Seebach, Dieter
    Exploring the Antibacterial and Hemolytic Activity of Shorter- and Longer-Chain B-, a,B-, and y-Peptides, and of B-Peptides from B2-3-Aza- and B3-2-Methylidene-amino Acids Bearing Proteinogenic Side Chains - A Survey2005In: Chemistry & Biodiversity, Vol. 2, p. 401-420Article in journal (Refereed)
    Abstract [en]

    The antibacterial activities of 31 different b-, mixed a/B-, and y-peptides, as well as of B-peptides derived from B2-3-aza- and B3-2-methylidene-amino acids were assayed against six pathogens (Enterococcus faecails, STaphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa), and the results were compared with literature data. The interaction of these peptides with mammalian cells, as modeled by measuring the hemolysis of human erythrocytes, was also investigated. In addition to those peptides designed to fold into amphiphilic helical conformations with positive charges on one face of the helix, one new peptide with hemolytic activity was detected within the sample set. Moreover, it was demontrated that neither cationic peptides used for membrane translocation (B3-oligoarginines), nor mixeda/B- or y-peptides with somatostatin-mimicking activities display unwanted hemolytic activity.

  • 190. Asgari, Parham
    et al.
    Hua, Yuanda
    Bokka, Apparao
    Thiamsiri, Chanachon
    Prasitwatcharakorn, Watcharapon
    Karedath, Ashif
    Chen, Xin
    Sardar, Sinjinee
    Yum, Kyungsuk
    Leem, Gyu
    Pierce, Brad S.
    Nam, Kwangho
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gao, Jiali
    Jeon, Junha
    Catalytic hydrogen atom transfer from hydrosilanes to vinylarenes for hydrosilylation and polymerization2019In: Nature Catalysis, ISSN 2520-1158, Vol. 2, no 2, p. 164-173Article in journal (Refereed)
    Abstract [en]

    Because of the importance of hydrogen atom transfer (HAT) in biology and chemistry, there is increased interest in new strategies to perform HAT in a sustainable manner. Here, we describe a sustainable, net redox-neutral HAT process involving hydrosilanes and alkali metal Lewis base catalysts-eliminating the use of transition metal catalysts-and report an associated mechanism concerning Lewis base-catalysed, complexation-induced HAT. The catalytic Lewis base-catalysed, complexation-induced HAT is capable of accessing both branch-specific hydrosilylation and polymerization of vinylarenes in a highly selective fashion, depending on the Lewis base catalyst used. In this process, the Earth-abundant, alkali metal Lewis base catalyst plays a dual role. It first serves as a HAT initiator and subsequently functions as a silyl radical stabilizing group, which is critical to highly selective cross-radical coupling. An electron paramagnetic resonance study identified a potassiated paramagnetic species, and multistate density functional theory revealed a high HAT character, yet multiconfigurational nature in the transition state of the reaction.

  • 191. Ashitani, T.
    et al.
    Kusumoto, N.
    Borg-Karlson, Anna Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Fujita, K.
    Takahashi, K.
    Antitermite activity of β-caryophyllene epoxide and episulfide2013In: Zeitschrift für Naturforschung C - A Journal of Biosciences, ISSN 0939-5075, E-ISSN 1865-7125, Vol. 68 C, no 7-8, p. 302-306Article in journal (Refereed)
    Abstract [en]

    Caryophyllene-6,7-epoxide and caryophyllene-6,7-episulfide can be easily synthesized from β-caryophyllene by autoxidation or episulfidation. The bioactivities of β-caryophyllene and its derivatives were investigated against the subterranean termite Reticulitermes speratus Kolbe. The antifeedant, feeding, and termiticidal activities of each compound were tested using no-choice, dual-choice, and non-contact methods. Antitermitic activities were not shown by β-caryophyllene, but were observed for the oxide and sulfide derivatives. Caryophyllene- 6,7-episulfide showed especially high antifeedant and termiticidal activities. Thus, naturally abundant, non-bioactive β-caryophyllene can be easily converted into an antitermite reagent via a non-biological process.

  • 192.
    Ashkan, Fardost
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Skillinghaug, Bobo
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Fredrik, Svensson
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Prasad, Wakchaure
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Matyas, Wejdemar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Mats, Larhed
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry.
    Christian, Sköld
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Pharmacy, Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry.
    Experimental and Theoretical Investigation of Palladium(II)-Catalyzed Decarboxylative Synthesis of Electron-Rich Styrenes and 1,1-DiarylethenesManuscript (preprint) (Other academic)
  • 193. Ashour, Radwa M.
    et al.
    Abdel-Magied, Ahmed F.
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Nuclear Materials Authority, Egypt.
    Abdel-Khalek, Ahmed A.
    Helaly, O. S.
    Ali, M. M.
    Preparation and characterization of magnetic iron oxide nanoparticles functionalized by L-cysteine: Adsorption and desorption behavior for rare earth metal ions2016In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 4, no 3, p. 3114-3121Article in journal (Refereed)
    Abstract [en]

    In this work, magnetic iron oxide nanoparticles functionalized with L-cysteine (Cys-Fe3O4 NPs) was synthesized and fully characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infra-red (FTIR), thermogravimetric analysis (TGA) and zeta potential measurements. The synthesized Cys-Fe(3)O(4)NPs has been evaluated as a highly adsorbent for the adsorption of a mixture of four rare earths RE3+ ions (La3+, Nd3+, Gd3+ and Y3+) from digested monazite solutions. The influence of various factors on the adsorption efficiency such as, the contact time, sample pH, temperature, and concentration of the stripping solution were investigated. The results indicate that Cys-Fe3O4 NPs achieve high removal efficiency 96.7, 99.3, 96.5 and 87% for La3+, Nd3+, Gd3+ and Y3+ ions, respectively, at pH = 6 within 15 min, and the adsorbent affinity for metal ions was found to be in order of Nd3+ > La3+ > Gd3+ > Y3+ ions. Using the Langmuir model, a maximum adsorption capacity of La3+, Nd3+, Gd3+ and Y3+ at room temperature was found to be 71.5, 145.5, 64.5 and 13.6 mg g (1), respectively. The Langmuir isotherm and pseudo-second order model fitted much better than the other isotherms and kinetic models. The obtained results for the thermodynamic parameters confirmed the spontaneous and endothermic nature of the process. Moreover, the desorption was carried out with 0.1 M nitric acid solutions. In addition, Cys-Fe3O4 NPs can be used as a highly efficient adsorbent for the adsorption of La3+, Nd3+, Gd3+ and Y3+ ions from digested monazite solutions.

  • 194.
    Aster, Alexander
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström. Univ Geneva, Dept Phys Chem, 30 Quai Ernest Ansermet, CH-1211 Geneva, Switzerland.
    Wang, Shihuai
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Mirmohades, Mohammad
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Esmieu, Charlène
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics. CNRS, LCC, 205 Route Narbonne,BP 44099, F-31077 Toulouse 4, France.
    Berggren, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Lomoth, Reiner
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Metal vs. ligand protonation and the alleged proton-shuttling role of the azadithiolate ligand in catalytic H-2 formation with FeFe hydrogenase model complexes2019In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 10, no 21, p. 5582-5588Article in journal (Refereed)
    Abstract [en]

    Electron and proton transfer reactions of diiron complexes [Fe(2)adt(CO)(6)] (1) and [Fe(2)adt(CO)(4)(PMe3)(2)] (4), with the biomimetic azadithiolate (adt) bridging ligand, have been investigated by real-time IR- and UV-vis-spectroscopic observation to elucidate the role of the adt-N as a potential proton shuttle in catalytic H-2 formation. Protonation of the one-electron reduced complex, 1(-), occurs on the adt-N yielding 1H and the same species is obtained by one-electron reduction of 1H(+). The preference for ligand vs. metal protonation in the Fe-2(i,0) state is presumably kinetic but no evidence for tautomerization of 1H to the hydride 1Hy was observed. This shows that the adt ligand does not work as a proton relay in the formation of hydride intermediates in the reduced catalyst. A hydride intermediate 1HHy(+) is formed only by protonation of 1H with stronger acid. Adt protonation results in reduction of the catalyst at much less negative potential, but subsequent protonation of the metal centers is not slowed down, as would be expected according to the decrease in basicity. Thus, the adtH(+) complex retains a high turnover frequency at the lowered overpotential. Instead of proton shuttling, we propose that this gain in catalytic performance compared to the propyldithiolate analogue might be rationalized in terms of lower reorganization energy for hydride formation with bulk acid upon adt protonation.

  • 195.
    Athley, Karin
    et al.
    RISE, Innventia.
    Granlöf, Lars
    RISE, Innventia.
    Söderberg, Daniel
    RISE, Innventia.
    Ström, Göran
    RISE, Innventia.
    Optimizing the benefit of retention chemicals2014Conference paper (Refereed)
    Abstract [en]

    Pre-flocculation of filler has been tested as a concept for improving the retention of filler and the strength properties of the sheet. The impact of the size of the filler floes on the mechanical retentionin a fibre network was investigated using a modified laboratory hand sheet former. The mechanical retention was found to increase linearly with both particle size and grammage of the fibre web. These results were confirmed in a full scale production trial on the FEX pilot paper machine at Innventia. Here different filler floe sizes were created through different chemical pre-flocculation strategies. The particle size in the flow to the headbox was measured with FBRM, and a linear relation between particle size and filler retention was found. Corresponding linear relation was seen in a pilot trial when adding filler and retention aid conventionally. This implies that mechanical retention constitute an important part of the filler retention not only upon pre-flocculation but also with conventional addition of filler and retention aid. Thus, the particle size before the headbox can be a good indicator of the retention level. For the conventional application of a two component retention aid system, the increased filler retention correlated to impaired formation and decreased sheet strength. On the contrary, pre-flocculation led to an increase in both sheet strength and filler retention, demonstrating the advantage of pre-flocculating filler.

  • 196. Atilaw, Yoseph
    et al.
    Duffy, Sandra
    Heydenreich, Matthias
    Muiva-Mutisya, Lois
    Avery, Vicky M
    Erdelyi, Mate
    Yenesew, Abiy
    Three Chalconoids and a Pterocarpene from the Roots of Tephrosia aequilata.2017In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 22, no 2, article id E318Article in journal (Refereed)
    Abstract [en]

    In our search for new antiplasmodial agents, the CH₂Cl₂/CH₃OH (1:1) extract of the roots of Tephrosia aequilata was investigated, and observed to cause 100% mortality of the chloroquine-sensitive (3D7) strain of Plasmodium falciparum at a 10 mg/mL concentration. From this extract three new chalconoids, E-2',6'-dimethoxy-3',4'-(2'',2''-dimethyl)pyranoretrochalcone (1, aequichalcone A), Z-2',6'-dimethoxy-3',4'-(2'',2''-dimethyl)pyranoretrochalcone (2, aequichalcone B), 4''-ethoxy-3''-hydroxypraecansone B (3, aequichalcone C) and a new pterocarpene, 3,4:8,9-dimethylenedioxy-6a,11a-pterocarpene (4), along with seven known compounds were isolated. The purified compounds were characterized by NMR spectroscopic and mass spectrometric analyses. Compound 1 slowly converts into 2 in solution, and thus the latter may have been enriched, or formed, during the extraction and separation process. The isomeric compounds 1 and 2 were both observed in the crude extract. Some of the isolated constituents showed good to moderate antiplasmodial activity against the chloroquine-sensitive (3D7) strain of Plasmodium falciparum.

  • 197. Atilaw, Yoseph
    et al.
    Muiva-Mutisya, Lois
    Ndakala, Albert
    Akala, Hoseah M
    Yeda, Redemptah
    Wu, Yu J
    Coghi, Paolo
    Wong, Vincent K W
    Erdelyi, Mate
    Yenesew, Abiy
    Four Prenylflavone Derivatives with Antiplasmodial Activities from the Stem of Tephrosia purpurea subsp. leptostachya.2017In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 22, no 9, article id E1514Article in journal (Refereed)
    Abstract [en]

    Four new flavones with modified prenyl groups, namely (E)-5-hydroxytephrostachin (1), purleptone (2), (E)-5-hydroxyanhydrotephrostachin (3), and terpurlepflavone (4), along with seven known compounds (5-11), were isolated from the CH₂Cl₂/MeOH (1:1) extract of the stem of Tephrosia purpurea subsp. leptostachya, a widely used medicinal plant. Their structures were elucidated on the basis of NMR spectroscopic and mass spectrometric evidence. Some of the isolated compounds showed antiplasmodial activity against the chloroquine-sensitive D6 strains of Plasmodium falciparum, with (E)-5-hydroxytephrostachin (1) being the most active, IC50 1.7 ± 0.1 μM, with relatively low cytotoxicity, IC50 > 21 μM, against four cell-lines.

  • 198.
    Aune, Marie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Danielsson, Rolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Hussenius, Anita
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Arts, Centre for Gender Research. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Ryberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Kristjansdottir, AG
    Uppsala University.
    Matsson, Olle
    Uppsala University.
    1,3-hydron transfer in some 5- or 7-substituted 1-methylindenes. Reaction rates and kinetic isotope effects1998In: Acta Chemica Scandinavica, ISSN 0904-213X, E-ISSN 1902-3103, Vol. 52, no 7, p. 911-920p. 911-920Article in journal (Refereed)
    Abstract [en]

    Rate constants and primary deuterium kinetic isotope effects (KIEs) have been determined for the base-catalysed 1,3-hydrotropic rearrangements of 1-methyl-5-nitroindene (12), 1-methyl-7-nitroindene (13), 5-methoxy-1-methylindene (14) and 5-fluoro-1-methy

  • 199.
    Aune, Marie
    et al.
    Uppsala University.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry.
    Matsson, Olle
    Uppsala University.
    Solvent Dependence of Enantioselectivity for a Base Catalyzed 1,3-Hydron Transfer Reaction: A Kinetic Isotope Effect and NMR Spectroscopic Study.1995In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 60, no 5, p. 1356-1364p. 1356-1364Article in journal (Refereed)
    Abstract [en]

    The base-catalyzed rearrangement of 1-methylindene (1) to 3-methylindene (2) has been studied. The reaction proceeds with substrate enantioselectivity (kinetic resolution) when chiral tertiary amines are used as catalysts. When dihydroquinidine (DHQD) (3

  • 200.
    Axelsson, Karolin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Chemical signals in interactions between Hylobius abietis and associated bacteria2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The pine weevil (Hylobius abietis L.) is one of the two topmost economically important insect pests in Swedish conifer forests. The damage increase in areas were the silvicultural practice is to use clear cuttings were the insects gather and breed. During egglaying the female protects her offspring by creating a cave in roots and stumps were she puts her egg and covers it with frass, a mixture of weevil feces and chewed bark. Adult pine weevils have been observed to feed on the other side of the egg laying site and antifeedant substance has been discovered in the feces of the pine weevil. We think it is possible that microorganisms present in the frass contribute with antifeedant/repellent substances. Little is known about the pine weevils associated bacteria community and their symbiotic functions. In this thesis the bacterial community is characterized in gut and frass both from pine weevils in different populations across Europe as well as after a 28 day long diet regime on Scots pine, silver birch or bilberry. Volatile substances produced by isolated bacteria as well as from a consortium of microorganisms were collected with solid phase micro extraction (SPME) and analyzed with GC-MS. The main volatiles were tested against pine weevils using a two-choice test. Wolbachia, Rahnella aquatilis, Serratia and Pseudomonas syringae was commonly associated with the pine weevil. 2-Methoxyphenol, 2-phenylethanol, 3-methyl-1-butanol were found in the headspace from Rahnella aquatilis when grown in substrate containing pine bark. 2-Methoxyphenol and 3-methyl-1-butanol, phenol and methyl salicylate were found in pine feces. Birch and bilberry feces emitted mainly linalool oxides and bilberry emitted also small amounts of 2-phenylethanol.

    A second part of the thesis discusses the role of fungi in forest insect interactions and the production of oxygenated monoterpenes as possible antifeedants. Spruce bark beetles (Ips typhographus L.) aggregate with the help of pheromones and with collected forces they kill weakened adult trees as a result of associated fungi growth and larval development. A fungi associated with the bark beetle, Grosmannia europhoides, was shown to produce de novo 2-methyl-3-buten-2-ol, the major component of the spruce bark beetle aggregation pheromone. Chemical defense responses against Endoconidiophora polonica and Heterobasidion parviporum were investigated using four clones of Norway spruce with different susceptibility to Heterobasidion sp. Clone specific differences were found in induced mono-, sesqui and diterpenes. A number of oxygenated monoterpenes which are known antifeedants for the pine weevil were produced in the infested areas.

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