Sökning: "ketones"

Visar resultat 21 - 25 av 108 avhandlingar innehållade ordet ketones.

  1. 21. The influence of temperature on enzyme selectivity in organic media

    Författare :Åsa Jönsson; Bioteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; water activity; sub-zero temperatures; enantioselectivity; peptide yields; asymmetric reductions of ketones; peptide synthesis; ADH from Thermoanaerobium brockii; subtilisin; Enzyme catalysis; a-chymotrypsin; organic solvent; aqueous media; Biotechnology; Bioteknik;

    Sammanfattning : The influence of different reaction parameters on enzyme selectivity was investigated. The reaction conditions studied were solvent dependence, water activity and reaction temperature. LÄS MER

  3. 22. Synthetic studies of nitrogen containing heterocycles, particularly pyrazole and benzotriazine derivatives

    Författare :Azadeh Nakhai; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :Pyrazole; indazole; tetrahydroindazoles; hexahydroindazoles; alpha; beta-unsaturated ketones; dihydropyrazolone; 3; 3 -biindolyl; 3; 3 -biindazolyl; o-azidobenzonitriles; benzotriazine; aryl-triazene;

    Sammanfattning : This thesis will mainly focus on the chemistry of nitrogen containing heterocyclic compounds, particularly pyrazole and benzotriazine and related ring systems to these compounds. The first part includes a short introduction to biologically important compounds as well as a description of reactivity and chemistry of benzo[c]pyrazole (indazole) and its derivatives. LÄS MER

  4. 23. Synthesis of Organofluorine Compounds and Allenylboronic Acids - Applications Including Fluorine-18 Labelling

    Författare :Denise N. Meyer; Kálmán J. Szabó; Dominique Cahard; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; boron; allenylboronic acid; BINOL; homopropargyl alcohol; organocatalyst; organoboron; organofluorine; fluorine; fluorine-18; late-stage; labelling; labeling; nucleophilic; electrophilic; fluorination; positron emision tomography; PET; radiotracer; hypervalent iodine; benziodoxole; benzoxazepines; diaryliodonium salt; metal-free; neutrophil elastase; NE; neutrophil elastase inhibitor; trifluoromethylation; trifluoromethylthiolation; difluoro enol silyl ethers; organisk kemi; Organic Chemistry;

    Sammanfattning : This work is focused on two areas: the chemistry of organofluorine and organoboron compounds. In the first chapter, a copper-catalysed synthesis of tri- and tetrasubstituted allenylboronic acids is presented. Extension of the same method leads to allenylboronic esters. LÄS MER

  5. 24. Selective transfer hydrogenations : Catalyst development and mechanistic investigations

    Författare :Jenny Wettergren; Hans Adolfsson; Serafino Gladiali; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; asymmetric catalysis; transfer hydrogenation; transition metal; amino acids; amino alcohols; Organic chemistry; Organisk kemi; Organic Chemistry; organisk kemi;

    Sammanfattning : By generating a library of amino acid-based ligands, pseudo-dipeptides, and combining them with transition metals, we have created selective and efficient ruthenium and rhodium catalysts for the asymmetric transfer hydrogenation of ketones. The ruthenium-catalyzed reaction was studied in detail, and we found that alkali metals play a crucial role for the reactivity and selectivity of the reaction. LÄS MER

  7. 25. Transition metal-catalyzed reduction of carbonyl compounds : Fe, Ru and Rh complexes as powerful hydride mediators

    Författare :Elina Buitrago; Hans Adolfsson; Robert Morris; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Asymmetric catalysis; amino acid; N-heterocyclic carbene; iron; ruthenium; rhodium; mechanistic investigation; kinetic study; asymmetric transfer hydrogenation; hydrosilylation; organisk kemi; Organic Chemistry;

    Sammanfattning : A detailed mechanistic investigation of the previously reported ruthenium pseudo-dipeptide-catalyzed asymmetric transfer hydrogenation (ATH) of aromatic ketones was performed. It was found that the addition of alkali metals has a large influence on both the reaction rate and the selectivity, and that the rate of the reaction was substantially increased when THF was used as a co-solvent. LÄS MER