Search for dissertations about: "amino acids synthesis"

Showing result 1 - 5 of 170 swedish dissertations containing the words amino acids synthesis.

  1. 1. Asymmetric Synthesis of C-Glycosylated Amino Acids : Incorporation in Collagen Glycopeptides and Evaluation in a Model for Rheumatoid Arthritis

    Author : Tomas Gustafsson; Jan Kihlberg; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Total synthesis; stereoselective synthesis; chiral glycine templates; Evan’s alkylation; asymmetric hydrogenation; alpha-amino acid synthesis; C-glycoside; rheumatoid arthritis; MHC; T cell; Organic chemistry; Organisk kemi;

    Abstract : This thesis describes stereoselective syntheses of four amino acids, three of which are C-glycosidic analogues of glycosylated amino acids. The overall goal of the project was to probe the interactions between MHC molecules, glycopeptide antigens and T cell receptors, that are essential for development of collagen induced arthritis. READ MORE

  2. 2. Amino acid-catalyzed synthesis of amino acid derivatives : Application and semi-synthesis of Paclitaxel, Docetaxel and their derivatives

    Author : Pawel Dziedzic; Armando Córdova; Stephen Hanessian; Stockholms universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Organocatlysis; amino acids; syntesis; Taxol and Taxotere derivatives; Chemistry; Kemi; organisk kemi; Organic Chemistry;

    Abstract : This thesis deals with different applications of organocatalysis, where amino acid derivatives and small peptides are applied as catalysts. First, the development of environmentally friendly aldol reactions, carried out in aqueous media is illustrated. The corresponding β-hydroxy ketones are formed with ee´s up to 99%. READ MORE

  3. 3. New Methodologies in Organic Chemistry: Applications to the Synthesis of α-Amino Acids and Natural Products

    Author : Sebastian Hirner; Peter Somfai; Varinder Aggarwal; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Organic synthesis; 2-Vinylaziridines; 3-Pyrrolines; Ringexpansion; Rearrangement; Anisomycin; Total synthesis; α-Amino acids; Arylglycines; Weinreb amides; α-Arylation; Grignard reagents; Umpolung; Organic chemistry; Organisk kemi;

    Abstract : This thesis deals with the development and application of new synthetic methodology in organic chemistry. The first part describes the development of a new protocol for the synthesis of 3-pyrrolines by means of a microwave-assisted ring-expansion reaction of 2-vinylaziridines. READ MORE

  4. 4. Synthesis of aromatic bis- and tris(amino acids) and chiral dendrimers

    Author : Andreas Ritzén; Centrum för analys och syntes; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Organisk kemi; Organic chemistry; HWE reaction; asymmetric hydrogenation; Heck reaction; Amino acids; chiral dendrimers;

    Abstract : A number of protected aromatic bis- and tris(amino acids) have been synthesised by catalytic asymmetric hydrogenation of the corresponding didehydroamino acid derivatives. The didehydroamino acid derivatives were prepared either by a Heck coupling of a 2-amidoacrylate with an aryl dihalide, or by Horner-Wadsworth-Emmons olefination of aromatic aldehydes with phosphonylglycine reagents. READ MORE

  5. 5. Rate and Accuracy of Bacterial Protein Synthesis with Natural and Unnatural Amino Acids

    Author : Ka-Weng Ieong; Måns Ehrenberg; Simpson Joseph; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ribosome; protein synthesis; translation; efficiency-accuracy trade-off; kinetics; unnatural amino acids; Molecular Biology; Molekylärbiologi;

    Abstract : This thesis addresses different questions regarding the rate, efficiency, and accuracy of peptide bond formation with natural as well as unnatural amino acids: Which step is rate-limiting during peptide bond formation? How does the accuracy vary with different transfer RNAs (tRNAs) and codons and how is it relevant to the living cells? Does proofreading selection of codon reading occur in a single- or multi-step manner as theoretically suggested? How does the E. coli translation system discriminate unnatural amino acids? Based on that, how to improve the incorporation efficiencies of unnatural amino acids?Based on the study on pH dependence of peptide bond formation, we show that the rate of the chemistry of peptidyl transfer to aminoacyl-tRNA (AA-tRNA) Gly-tRNAGly or Pro-tRNAPro limits the rate of peptide bond formation at physiological pH 7. READ MORE