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  • 1
    Electronic Resource
    Electronic Resource
    De-novo-Synthese von Kohlenhydraten und verwandten Naturstoffen, 29. Synthese von partiell geschützten Zuckern aus meso-Divinylglycol (1988)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1988 (1988), S. 209-214 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: De novo Synthesis of Carbohydrates and Related Natural Products, 291). - Synthesis of Partially Protected Carbohydrates from meso-DivinylglycolSelective mono-O-benzylation of meso-divinylglycol (1) and subsequent Sharpless epoxidation afford the enantiomerically pure epoxide 3 which was cleaved with different nucleophiles at carbon atom 1. Cleavage with titanium tetrabenzylate affords directly the 1,4-di-O-benzyl-protected 5,6-dideoxy-L-ribo-hex-5-enitol 15 which provides after ozonolysis the 2,5-di-O-benzyl-D-ribose 16. O-Isopropylidenation of compound 15, subsequent hydroxylation of the vinyl group at the terminal C-atom, and oxidation to the aldehyde stage yield the O-protected 2-deoxy-D-ribo-hexose 19. Deisopropylidenation of this compound provides 3,6-di-O-benzyl-2-deoxy-D-ribo-hexose (20) whose structure is confirmed via the di-O-acetyl derivative 21 P.
    Notes: Selektive Mono-O-benzylierung von meso-Divinylglycol (1) und Sharpless-Epoxidation liefern das enantiomerenreine Epoxid 3, das mit verschiedenen Nucleophilen regioselektiv am C-Atom 1 geöffnet werden kann. Durch Öffnung mit Titantetrabenzylat wird direkt das 1,4-Di-O-benzyl-geschützte 5,6-Didesoxy-L-ribo-hex-5-enitol 15 erhalten, das nach Ozonolyse die 2,5-Di-O-benzyl-D-ribose 16 liefert. O-Isopropylidenierung von 15, Hydroxylierung der Vinylgruppe am endständigen C-Atom und Oxidation führen zur O-geschützten 2-Desoxy-D-ribo-hexose 19. Daraus wird durch Deisopropylidenierung die 3,6-Di-O-benzyl-2-desoxy-D-ribo-hexose (20) gewonnen, deren Stereostruktur im O-Acetylderivat 21 P bestätigt wird.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198819880305
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  • 2
    Electronic Resource
    Electronic Resource
    Glycal-1-ylmethylphosphonates - precursors of glycosyltransferase inhibitors (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 297-303 
    Details
    ISSN: 0170-2041
    Keywords: Carbohydrates ; Glycals ; C-Glycosides ; Hept-2-enoses, lyxo- ; D-Galactal-1-ylmethylphosphonates ; L-Fucal-1-ylmethylphosphonates ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Direct lithiation of 2-phenylsulfinyl- and 2-phenylsulfonylsubstituted galactal derivatives 3a-c and subsequent reaction with DMF gave 1-C-formyl derivatives 4a-c. Reduction afforded hydroxymethyl derivatives 5a-c which were transformed into mesylates 7 and 9, respectively. Treatment with trimethyl phosphite furnished phosphonates 8 and 10; by treatment with sodium in liquid ammonia and subsequent reaction with acetic anhydride in pyridine both compounds were converted into monomethyl galactal-1-ylmethylphosphonate (11) which could not be completely demethylated without structural change. O-Acetyl-protected mesylate 18, obtained from galactosyl cyanide in a few steps, was transformed into bromide 19 which on treatment with P(OSiMe3)3 gave bis(trimethylsilyl) phosphonate 20. Reaction with NaOMe/MeOH afforded the unprotected disodium salt of D-galactal-1-ylmethylphosphonate 1. Similarly, from L-fucopyranosyl cyanide 22 the corresponding target molecule 2 was obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419940312
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  • 3
    Electronic Resource
    Electronic Resource
    Multiple Column Synthesis of a Library of T-Cell Stimulating Tn-Antigenic Glycopeptide Analogues for the Molecular Characterization of T-Cell-Glycan Specificity (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Peptide Science 2 (1996), S. 212-222 
    Details
    ISSN: 1075-2617
    Keywords: mucin glycopeptides ; tumour associated antigen ; cancer ; MHC Class II binding ; glycopeptide synthesis ; Chemistry ; Biochemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of peptides and glycopeptides derived by amino acid and glycosyl amino acid scans through the self peptide from CBA/J mouse haemoglobin Hb (67-76), VITAFNEGLK, was synthesized by multiple column peptide synthesis (MCPS). Investigation of glycopeptide binding to the mouse major histocompatibility class II molecule Ek showed that glycans in position 72 did not interfere with the binding to Ek. Immunization experiments revealed that glycopeptides with the glycan in position 72 were immunogenic. Therefore a series of N-linked and O-linked glycopeptides with the glycan attached in the position 72 either to serine, threonine or asparagine was synthesized by MCPS. The glycan structure was furthermore varied with respect to monosacc haride component, size of oligosaccharide, anomer configuration and stereoche mistry of essential hydroxyl groups in order to investigate the specificity of the interaction with the T-cell receptor. Easy synthesis of ready to use Ser and Thr building blocks corresponding to mucin core 1, the Tn-antigen and its β-anomer were developed using trichloroacetimidates as glycosyl donors and reduction with in situ acetylation of the azide containing glycosylation products. Synthesis of an α-linked GlcNAc-Thr building block was achieved by glycosylation of Fmoc-Thr-OPfp with 2-azido-2-deoxy-3,4,6-tri-O-acetyl-D- glycopyranosyl trichloroacetimidate as a glycosyl donor. Other building blocks were obtained by previously described procedures.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/psc.64
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