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  • 1
    Electronic Resource
    Electronic Resource
    Strukturelle Abwandlungen anN-Acetylneuraminsäure, 4. Mitt. Transformationen am Diethyl-dithioketal desN-Acetylneuraminsäure-γ-lactons (1985)
    Springer
    Monatshefte für Chemie 116 (1985), S. 253-262 
    Details
    ISSN: 1434-4475
    Keywords: 9,8,7,6-Tetra-O-acetyl-N-acetylneuraminic acid-γ-lactone, synthesis of ; N-Acetylneuraminic acid-γ-lactone diethyldithioketale ; Sylilation with t-butyldimethylchlorosilane and TIPSiCl2 ; 6,7-Carbonate ofN-Acylneuraminic acid-γ-lactone diethyldithioketal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Partial protection of diethyldithioketal ofN-acetylneuraminic acid-γ-lactone using one or two equivalents oft-butyldimethylchlorosilane leads to the 9-O-silyletherderivative7 and the 8,9-bis-O-silylderivative5, resp. The reaction of1 as well as7 with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane (TIPSiCl2) yields selectively the protected products4 and9. The 9,8,7,6-tetra-O-acetyl-N-acetylneuraminic acid-γ-lactone derivative3 is formed by the oxidative desulfurazation of the peracteylated form of1 (i. e.2) by means ofNBS. By reaction of5 withTPPDEAD the 6,7-carbonato compound6 arises instead of the expected 6,7-epoxyderivative. The analogous carbonate8 is formed by treating7 with bisimidazolylcarbonate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00798461
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  • 2
    Electronic Resource
    Electronic Resource
    Indium-assisted allylation in carbohydrate chemistry: A convenient route to D-glycero-D-galacto- and D-glycero-L-galacto-heptose (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 73-78 
    Details
    ISSN: 0170-2041
    Keywords: Allylation, indium-assisted ; Aldoheptoses ; Catalytic osmylation ; Indium-assisted allylation ; Carbohydrates ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Starting with unprotected D-pentoses 1-4 we achieved a chain elongation reaction by utilizing indium-assisted allylation. After acetylation, the polyol derivatives 1a-4a were transformed into the corresponding α,β-unsaturated aldehydes 1b-4b. Protection of the carbonyl group yielded the diethyl acetals 1c-4c. Subsequent dihydroxylation of the double bond by catalytic osmylation followed by acetylation of the newly introduced hydroxyl functions gave a mixture of diastereomeric products. However, only those diastereomers could be easily separated by column chromatography which were derived from 1c and 2c, giving access to D-glycero-D-galacto and D-glycero-L-galacto precursor 5 and 7, respectively. Final deprotection yielded the title aldoheptoses 6 and 8.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419940113
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