Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles: DFG German National Licenses  (6)
  • Saccharides  (6)
  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of a Hydroxymethylene-Bridged Galβ(→3)Gal c-Disaccharide (1992)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1992 (1992), S. 983-986 
    Details
    ISSN: 0170-2041
    Keywords: D-Galactal ; Galactopyranosides ; Carbohydrates ; Disaccharides ; Saccharides ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Direct lithiation of the readily available 2-phenylsulfinyl-D-galactal 3S furnishes with aldehyde 8 as electrophile in a diastereocontrolled reaction the C-disaccharide intermediate 9. Subsequent removal of the phenylsulfinyl group with Raney nickel and diastereospecific 2b-hydrogen and 3b-hydroxy transfer provide the β(1→3)-connected C-disaccharide 11 in high yield. The structure of 11 was deduced from its derivative 12 on the basis of 1H-NMR data. Hydrogenolytic O-debenzylation gives compound 13, which is characterized as O-acetylated compound 14.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1992199201161
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Glycosyl Imidates, 62. - Synthesis of the Heptasaccharide Moiety of Ganglioside BGM1 (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 859-864 
    Details
    ISSN: 0170-2041
    Keywords: Glycosphingolipids ; Ganglio series ; Blood group B determinant ; Glycosides ; Trichloroacetimidates ; Saccharides ; Carbohydrates ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the O-acetyl protected heptasaccharide moiety (2) of BGM1 was performed according to the following reaction sequence: Reaction of 2,3-di-O-acetyl-4,6-O-benzylidenegalactosyl trichloroacetimidate 4 (as donor) with 3-O-unprotected 2-azidogalactose 5 (as acceptor) gave β(1→3)-connected disaccharide 6. Subsequent O-deacetylation followed by reaction with galactosyl donor 8 afforded regioselectively trisaccharide 9 which was converted into tetrasaccharide 12 by treatment with fucosyl donor 11. Transformation of 12 via acid-catalyzed O-deisopropylidenation, O-acetylation, anomeric O-desilylation, and then base-catalyzed treatment with trichloroacetonitrile afforded trichloroacetimidate 16 as tetraosyl donor. Reaction of 16 with the known 4b-O-unprotected sialyllactose derivative 17 gave in acetonitrile at -40°C in the presence of TMSOTf as the catalyst the desired heptasaccharide 18. Azido group reduction with propanedithiol, N-acetylation, hydrogenolytic O-debenzylation, and O-debenzylidenation under acidic conditions followed by O-acetylation afforded the target molecule 2. The structural assignments were based on the 1H-NMR data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1993199301136
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Glycosyl Imidates, 66. Synthesis of the Tetrasaccharide Moiety of Plant Growth Regulator Calonyctin A (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 645-651 
    Details
    ISSN: 0170-2041
    Keywords: Calonyctin A ; Saccharides ; Resin glycosides ; Glycosides ; Trichloroacetimidates ; Carbohydrates ; D-Quinovose ; L-Rhamnose ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-O-Benzyl-protected quinovose 6 was transformed into 1,2-O-unprotected derivative 9 which on treatment with TBS-Cl in the presence of a base gave selectively 2-O-unprotected glycosyl acceptor 10. Similarly, 3-O-allyl-protected quinovose 11 was transformed into 1,2-O-unprotected derivative 14. 1,2-O-Acetylation of 14, selective removal of the 1-O-acetyl group with hydrazinium acetate, and subsequent treatment with trichloroacetonitrile in the presence of DBU furnished the versatile 2-O-acetyl-3-O-allyl-protected quinovosyl donor 17. Reaction of donor 17 with acceptor 10 in the presence of TMSOTf as the catalyst gave disaccharide 19. Treatment of 19 with NaOMe/MeOH provided 2b-O-unprotected derivative 20 which gave with rhamnosyl donor 18 in the presence of TMSOTf as the catalyst trisaccharide 21. 3b-O-Deallylation of 21 and subsequent reaction with donor 17, again in the presence of TMSOTf as the catalyst, gave target tetrasaccharide 2. Removal of all O-protective groups furnished D-Quiß(1→3)[L-Rhaα(1→2)]D-Quiß(1→2)D-Qui (3), the tetrasaccharide moiety of calonyctin A.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419940702
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Glycosyl Phosphites as Glycosyl Donors - A Comparative Study (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 325-329 
    Details
    ISSN: 0170-2041
    Keywords: Glycosides ; Phosphites ; Lewis antigen X (LeX) and A (Lea) ; Carbohydrates ; Saccharides ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tri-O-benzyl-L-fucose (3) was transformed into the bis(trichloroethyl) phosphite derivative 4 which was allowed to react with 3-O-unprotected azidoglucose 7 as fucosyl acceptor in the presence of TMSOTf as catalyst to furnish disaccharide building block 1, useful in Lewis antigen X (LeX) synthesis, in 75% yield. Similarly, 2,3,4,6-tetra-O-acetyl-D-galactose (8) was transformed into the bis(trichloroethyl) phosphite derivative 9 which afforded by treatment with acceptor 7 disaccharide 10 in 64% yield. The reaction of the derived acceptor 11 with donor 4 furnished trisaccharide building block 12, useful in Lewis antigen A (Lea) synthesis, in 88% yield. Transformation into the less reactive donor 14 and reaction with lactose acceptor 15 gave pentasaccharide 2 only in modest yield, thus exhibiting the scope and limitations of phosphite leaving groups in glycosylation reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419940403
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Glycosyl Imidates, 61. - Synthesis of the Hexasaccharide Moiety of the Saponin Holotoxin A (1993)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 853-858 
    Details
    ISSN: 0170-2041
    Keywords: Glycosides ; Trichloroacetimidates ; Xylose ; Quinovose ; Saponins ; Holotoxin A ; Sea cucumbers ; Stichopus japonicus SELENCA ; Carbohydrates ; Saccharides ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of O-(3-O-methylglucosyl) trichloroacetimidate 2a as glycosyl donor and 1,2:5,6-di-O-isopropylidene-D-glucofuranose (3) as glycosyl acceptor furnished in the presence of TMSOTf as catalyst the β-(1→3)-connected disaccharide 5a. Similarly, from O-quinovosyl trichloroacetimidate 2b and 3 the disaccharide 5b was obtained. Compound 5a was transformed via acid-catalyzed O-deisopropylidenation, O-acetylation, and selective 1-O-deacetylation into 7. Treatment of 7 with trichloroacetonitrile in the presence of DBU furnished trichloroacetimidate 8 as glycosyl donor. Reaction of 8 with 2,4-O-unprotected xylopyranoside 9 as glycosyl acceptor afforded selectively trisaccharide 10. Similarly, reaction of 8 with 2,4-O-unprotected quinovoside 12 furnished selectively trisaccharide 13 which gave upon O-acetylation, 1-O-desilylation, and then treatment with trichloroacetonitrile in the presence of DBU trichloroacetimidate 15 as triosyl donor. Reaction of 10 with 15 in the presence of TMSOTf as catalyst led to hexasaccharide 16; ensuing hydrogenolytic O-debenzylation and then O-acetylation afforded the desired hexasaccharide 17.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1993199301135
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Glycosyl Imidates, 56. Synthesis of the Hexasaccharide Moiety of Pectinioside E (1992)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1992 (1992), S. 975-982 
    Details
    ISSN: 0170-2041
    Keywords: Steroids ; Glycosides ; Saponins ; Pectinioside E ; Saccharides ; Trichloroacetimidates ; Carbohydrates ; Starfishes ; Asterina pectinifera ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the hexasaccharide moiety 2 of pectinioside E (1), isolated from the whole bodies of the starfish Asterina pectinifera Müller et Troschel, is described. Building block 4 was prepared by a six-step procedure from D-glucose. A reasonable yield was obtained via selective glycosylation of 4 at 2-OH with donor 5 to give the desired disaccharide 6 which served as an acceptor in the following fucosylation with 9 to afford the crucial trisaccharide 10. This was easily transformed into trichloroacetimidate 12. Disaccharide 17, obtained in high yield by glycosylation of donor 13 with acceptor 14 followed by deacetylation, turned out to be more reactive at 4b-OH than at 2b-OH. Thus, the reaction of donor 12 with acceptor 17 gave the desired pentasaccharide 18 β in an acceptable yield; 18 β was readily transformed into the hexasaccharide 20 by glycosylation with donor 15. Debenzylation of 20 followed by deacylation furnished the target hexasaccharide 2 which was characterized by its per-O-acetylated product 21.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1992199201160
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...