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  • 1.
    Abbas, Alaa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC.
    Palladium-Catalysed Carbonylative Synthesis of Acylamidines2014Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
  • 2.
    Blomkvist, Björn
    KTH, Skolan för kemivetenskap (CHE).
    The application of reversible covalent bonds in catalysis2014Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    I detta projekt har ligandutbyte på trimetylborat, samt dess möjlighet att inducera intramolekularitet studerats. Experiment har utförts som inriktats på en fördjupad förståelse för boraffiniteten hos alkoholer och aminer, samt jämvikterna i dessa system. Vidare har reaktioner screenats i sökandet efter en reaktion som kan katalyseras av inducerad intramolelcularitet av trimetylborat.

  • 3.
    Dhillon, Prakriti
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för kemi och biomedicin (KOB).
    Cobalt-catalysed, regioselective C-H activation of amides with unsymmetrical 1,3-diynes using 8-aminoquinoline as a bidentate directing group2018Självständigt arbete på avancerad nivå (masterexamen), 80 poäng / 120 hpStudentuppsats (Examensarbete)
    Abstract [en]

    A cobalt-catalysed, ortho-directed, C-H activation of 8-aminoquinoline amides for the preparation of functionalised isoquinolones is reported. The C-H activation was performed with the amide derived from 8-aminoquinoline which acts as a bidentate directing group to facilitate the C-H activation at the ortho carbon atom of the amide towards annulation/cyclisation, with unsymmetrical 1,3-diynes. The work presented here is an exploration of the regiochemical outcome of an efficient and a novel route of synthesis that tries to gain a deeper insight into the regioselective preference for C-H activated annulations that result in the formation of a diverse range of alkynylated regioisomeric heterocycles. Of the four possible regioisomers, only one is formed as the major product depending on the stereoelectronic properties of the diyne in combination with the nature of the 8-aminoquinoline amide.

  • 4.
    Fauquet, Germain
    KTH, Skolan för kemivetenskap (CHE).
    Reconnaissance biomoléculaire, Comparaison de l'impact du soufre et de l'oxygène dans la liaison glycosidique2011Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Interactions between carbohydrates and proteins play a key role in many biological processes. Cell-cell interactions, cell communication and cell proliferation are examples of processes based on highly specific interactions between proteins and complex oligosaccharides. The synthesis of carbohydrate mimics is essential for the study and understanding of such recognition processes, and has therefore become increasingly popular over the latest decades. In synthesis, thiol derivatives have several advantages. Thus, the combined nucleophilicity and chemical stability of sulfhydryl groups render thiol carbohydrate analogs as excellent building blocks for glycosylation processes. The objectives of the present project were to investigate the differences between naturally occurring oligosaccharides and their sulfur-analogs in biomolecular interactions with specific proteins. Convenient methodologies to the synthesis of a range of D-mannopyranose thioanalogs were developed. These strategies allows for the access to 1,2- and 1,6-linked dimannosides by glycosylation. A carbohydrate-protein interaction methodology to test the developed compounds against a mannose-specific lectin (Concanavalin A) using quartz crystal microbalance (QCM) methodology was furthermore developed.

  • 5.
    Kinschel, Dominik
    KTH, Skolan för kemivetenskap (CHE).
    Stable Redox Systems for Dye-Sensitized Solar Cells2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Dye sensitized solar cells are a new type of solar cells which open a new market thanks to their unique properties, which are semi transparency and the fact that they can be produced in various colors.

    After improving two existing syntheses for industrial applications, this thesis takes the approach to develop new redox mediators for devices with an aim on improving stability. Five redox mediators with cobalt, copper and iron as metal center were synthesized and characterized by NMR spectroscopy, cyclic voltammetry and UV/VIS spectrophotometry. Three of them were selected for evaluation in test cells. Most promising results were obtained with a copper complex, using the tandem redox approach a new record efficiency of 7.7% for copper based electrolytes in dye-sensitized solar cells was obtained.

  • 6.
    SEIGEL, KAROLINA
    KTH, Skolan för kemivetenskap (CHE).
    Hydrogen Bonding Catalysis of Imine Exchange with Thiourea and Squaramide Donors2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

     

    Syftet med detta projekt har varit att utforska möjligheten för aromatiska tioureor och skvaratamider att katalysera en reversibel iminutbytesreaktion genom vätebindningskatalys. Det primära målet var att finna en organokatalysator som skulle kunna ersätta eller vara ett komplement till befintliga katalysatorer för att möjliggöra nya tillämpningar. Flera parametrar såsom katalysatorns sammansättning och koncentration samt beroendet av lösningsmedel och vattenmängd har undersökts. Resultaten tyder på att ett lågt pKa för de vätebindningsdonerande väteatomerna och ett polärt och ickekoordinerande lösningsmedel är väldigt viktigt för att nå jämvikt på kort tid. Katalysatorerna har dessutom visat sig ha hög aktivitet även vid låga koncentrationer och förmågan att katalysera mer än ett steg i utbytesreaktionen. Tiden för att uppnå jämvikt bestämdes genom att regelbundet mäta integralerna för iminernas signaler i ett 1H NMR-spektrum, medan reaktionen pågick.

  • 7.
    Song, Yan
    KTH, Skolan för kemivetenskap (CHE).
    Regio- and Stereoselectivity in Glycosyl Disulfide Desulfurization. Generation of S-linked Disaccharides2011Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This report describes the synthesis of thiomonosaccharides and the subsequent oxidation to carbohydrate disulfides followed by evaluation of a desulfurization reaction with the aim of developing a facile method for production of S-linked oligosaccharides. The carbohydrate disulfides were synthesized in few steps from commercially available starting materials. Small and simple disulfides were used to evaluate the desulfurization process yielding important information about choice of solvent, catalyst and temperature required for the desulfurization to occur. The optimized conditions were then applied to the carbohydrate disulfides. Results showed that the reactivity of the carbohydrate disulfides depends a lot on the position of the disulfide. One of the carbohydrate disulfides was efficiently desulfurized giving the thioether linked disaccharide, as determined by mass spectrometry. However, more work is needed to develop a general procedure for the desulfurization working on many different carbohydrate disulfides.

  • 8.
    Starkholm, Allan
    KTH, Skolan för kemivetenskap (CHE).
    Synthesis of Water-Soluble Catalysts for Olefin Metathesis2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The need of efficient and sustainable chemical processes in the field of organic chemistry is essential in order to meet the environmental demands that societies and industries require from us. One key chemical reaction that is widely used in industrial plants is olefin metathesis, a reaction that involves exchange and formation of C-C double bonds. It is a crucial reaction in polymerization reactions and as a means of connecting building blocks together. Consequently it is necessary to enable these reactions to work in aqueous media for increased sustainability and for applications in biochemistry. Carbenes are a class of compounds that constitute a crucial role as ligands in olefin metathesis catalysts. This project will aim to explore the water applicability of a certain category of carbenes, cyclic (alkyl)-(amino)carbenes (CAAC), which recently have caught attention due to their remarkable catalytic activity in organometallic catalysis. The CAAC based catalysis display high stability towards air and moisture, and thus making them attractive alternatives for industrial applications. Throughout the project, synthetic routes towards water soluble CAAC:s have been designed and investigated. Moreover, an approach of evaluating a CAAC-ruthenium catalyst in micellar solutions have been investigated and illustrated promising results regarding activity and stability.

  • 9.
    Svensson, Fredric
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för kemi och biomedicin (KOB).
    Identification, Synthesis and Characterization of Semiochemicals of some Forest Beetles2015Självständigt arbete på avancerad nivå (masterexamen), 30 poäng / 45 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This work consists of three parts. Part one deals with the syntheses of a number of common Cerambycidae and bark beetle semiochemicals. Additionally, syntheses for three new suspected Cerambycidae semiochemicals were developed. In part two, the elution order and Kovats retention indices of various bark beetle associated semiochemicals were determined on an enantioselective GC-column. In part three, SPME/GC-MS analyses of bark beetle associated fungi cultivations on terpenes were undertaken to find fungal degradation products with known electrophysical activity to bark beetles. A large number of bark beetle semiochemicals were found, including two bark beetle pheromones.

  • 10.
    Widing, Joakim
    KTH, Skolan för kemivetenskap (CHE).
    Preparation of Affinity Based Probes to Elucidate the Mode of Action of y-Secretase Modulators2011Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    γ-Secretase is an enzyme that takes part of the breakdown of amyloid precursor protein (APP) into amyloid-β (Aβ) peptides. Aβ-peptides from this process can be linked to Alzheimer’s disease. γ-Secretase modulators (GSMs) have been reported in the literature to reduce the potentially dangerous variant of Aβ-peptides. However, the mechanism of the binding site for these modulators is poorly understood. In this report substances of affinity based probes (AfBPs) have been prepared that can be used as a method to extract the binding site. The AfBPs were constituted of a cross-linking group, a biotinyl group and a γ-secretase modulator. Different variants of the biotin probe were prepared to investigate if the activity of the original modulator could be retained. The report will show that this could be done.

    In the future, the synthesised affinity based probes could be used to understand the mode of action of γ-secretase modulators. For instance the modulator could be incubated with the enzyme and the crosslinking group, when activated, covalently bind to a residue near the binding site. The complex could then be captured on avidin and the binding site be determined.

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