- LEWISSAEURE-KATALYSIERTE SYNTHESEN VON DI- UND TRI-SACCHARID-SEQUENZEN DER O- UND N-GLYCOPROTEINE, ANWENDUNG VON TRIMETHYLSILYLTRIFLUOROMETHANESULFONAT
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In the presence of trimethylsilyltrifluoromethanesulfonate as Lewis acid catalyst, β-acetates reacted, as glycosyl donors and with neighboring-group participation, with secondary hydroxyl groups of saccharides having low reactivity to give β-glycosidicall
- Paulsen, Hans,Paal, Michael
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- Blood-group Ii-Active Oligosaccharides. Synthesis of a Tetrasaccharide, a β-(1->3) Dimer of N-Acetyl-lactosamine
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Condensation of benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside (2) with 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide, followed by de-O-acetylation, acetonation, O-benzoylation, and acidic hydrolysis afforded the 3',4'-diol (5) derived from N-acetyl-lactosamine.This compound was selectively glycosylated at the 3'-position by the oxazoline (7) derived from lactosamine to give the protected tetrasaccharide (8) in 52percent yield.Removal of the protecting groups gave the free tetrasaccharide β-D-Galp-(1->4)-β-D-GlcpNAc-(1->3)-β-D-Galp-(1->4)-D-GlcpNAc (9), a β-(1->3) dimer of N-acetyl-lactosamine.This structure has been found in various glycolipids isolated from erythrocyte membranes and could be recognized by several anti-i antisera.
- Veyrieres, Alain
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p. 1626 - 1629
(2007/10/02)
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- Bausteine von Oligosacchariden, XX. Synthese der Oligosaccharid-Determinanten der Blutgruppensubstanzen der Type 2 des ABH-Systems. Diskussion der &α-Glycosid-Synthese
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The antigenic determinants of type 2 of blood-group substances A and B (23 and 24) as well as blood-group substance H (17) were synthesized by selective glycosidation reactions combined with a series of blocking and deblocking steps.The possibilities and optimization of the α-glycoside synthesis are discussed.In hemagglutination inhibition tests the synthetic haptens A and B of type 2 and type 1 show a similar selective inhibitory effect.In case of hapten H, however, great differences can be observed.Here the type 2 exhibited a strong inhibition activity, whereas type 1 only showed an extremly low activity.This leads to the conclusion that in the determinants of the ABH-system on the surface of erythrocytes the chemical structure of type 2 is predominating.
- Paulsen, Hans,Kolar, Cenek
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p. 306 - 321
(2007/10/02)
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- Synthesis of Blood-group Substances. Part 11. Synthesis of the Trisaccharide O-α-D-Galactopyranosyl-(1-->3)-O-β-D-galactopyranosyl-(1-->4)-2-acetamido-2-deoxy-D-glucopyranose
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Reaction of 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide with benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside in 1,2-dichloroethane in the presence of mercuric bromide and molecular sieves (4 Angstroem) provided after O-deacetylation
- Jacquinet, Jean-Claude,Duchet, Danielle,Milat, Marie-Louise,Sinay, Pierre
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p. 326 - 330
(2007/10/02)
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