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Visar resultat 6 - 10 av 26 avhandlingar som matchar ovanstående sökkriterier.

  1. 6. Non Natural Aromatic Amino Acids Applications in cage-construction, metal ion coordination and asymmetric catalysis

    Författare :Ruxandra Ionescu; Centrum för analys och syntes; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diethylzinc additions.; spectroscopy; metal ion coordination; cage-like compounds; Amino acids; C3-symmetry; Organic chemistry; Organisk kemi;

    Sammanfattning : Aromatic non-natural amino acids, the outstanding feature of which was the presence of several arms, were synthesised and their properties investigated. The amino acids were synthesised following a standard procedure starting with a Horner-Wadsworth-Emmons or a Heck reaction, which provided didehydroamino acids. LÄS MER

  3. 7. Bispyridylamides as ligands in asymmetric catalysis

    Författare :Oscar Belda de Lama; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; asymmetric catalysis; chiral ligand; pyridine; amide; allylic alkylation; enantioselective; cyanation; ring-opening; chiral Lewis acid;

    Sammanfattning : This thesis deals with the preparation and use of chiralbispyridylamides as ligands in metal-catalyzed asymmetricreactions. The compounds were prepared by amide formation usingdifferent coupling reagents. LÄS MER

  4. 8. 13C-Enriched Dehydrogenation Polymers Used for Studying Light-Induced Yellowing of Lignocellulosic Materials

    Författare :Jim Parkås; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; lignin model compounds; differentiating xylem; yellowing; Picea abies; 13C NMR spectroscopy; lignin; DHP; 13C-enrichment; solid state; spruce;

    Sammanfattning : This study deals with the use of selectively 13C-enriched dehydrogenation polymers (DHPs) as models of lignin in lignocellulosic materials for elucidating the reaction pathways involved in light-induced yellowing. Methods for the synthesis of coniferin, a precursor to lignin and DHP, selectively 13C-enriched in the aromatic ring (positions 1, 3, 4, and 5) have been developed. LÄS MER

  5. 9. Metallocene based peptidomimetics and chiral catalysts

    Författare :Suzana Maricic; Centrum för analys och syntes; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; Organisk kemi; asymmetric catalysis.; metallocene based amino alcohols; one-pot macrocyclisation; cyclic peptides; Organometallic substance P and Leu 5 -enkephalin; conformational analysis;

    Sammanfattning : Several optically active organometallic Phe-AAn-Phe peptidomimetics and macrocyclic Phe-(Phe)n peptides have been synthesized by either intra- or intermolecular peptide bond formation of the corresponding bis(amino acid) derivatives. The key bis(amino acid) derivatives were available from an improved multi-step synthetic route, utilising Horner-Wadswort-Emmons olefination of organometallic aldehydes with phosphonylglycine reagents, enantioselective hydrogenation of didehydro amino acids and classical solution and/or solid phase peptide synthesis methodology. LÄS MER

  7. 10. Discovery-Oriented Screening of Dynamic Systems: Combinatorial and Synthetic Applications

    Författare :Marcus Angelin; Olof Ramström; Stefan Kubik; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; chemical education; crystallization; dynamic combinatorial chemistry; dynamic combinatorial resolution; dynamic system; enzyme catalysis; isoindolinone; lipase; nitroalcohol; nitroaldol reaction; phthalide; reversible; secondary alcohol; systems chemistry; tandem reaction; Organic chemistry; Organisk kemi; Bioorganic chemistry; Bioorganisk kemi;

    Sammanfattning : This thesis is divided into six parts, all centered around the development of dynamic (i.e., reversibly interacting) systems of molecules and their applications in dynamic combinatorial chemistry (DCC) and organic synthesis. LÄS MER