Conformational analysis of β-linked glucobiosides based on hetero- and homonuclear couplings across the glycosidic linkage
2008 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Journal of physical chemistry, ISSN 0022-3654, Vol. 112, no 14, 4447-4453 p.Article in journal (Refereed) Published
Four β-linked glucobioses selectively 13C labeled at C1‘ or C2‘ have been prepared. The inter-residue coupling constants, JCH, and JCC, have been determined and related to the solution conformations of the disaccharides using Karplus-type relationships. Relying only on the experimental coupling constants, glycosidic linkage conformation in methyl α-sophoroside (methyl 2-O-β-d-glucopyranosyl-α-d-glucopyranoside), methyl α-laminarabioside (methyl 3-O-β-d-glucopyranosyl-α-d-glucopyranoside), and methyl α-cellobioside (methyl 4-O-β-d-glucopyranosyl-α-d-glucopyranoside) were found to be close to those observed in the solid state (39° < H < 41°, −24° < ψH < −36°). The laminarabioside and cellobioside were found to have conformations that accommodate an intramolecular hydrogen bond to O5‘ that is observed in the solid state. In all compounds, the exocyclic hydroxymethyl groups retain a conformation close to that observed in unsubstituted glucose (gt/gg 1:1). Methyl α-gentiobioside (methyl 6-O-β-d-glucopyranosyl-α-d-glucopyranoside) shows greater flexibility at the ψ-torsion than the other disaccharides, but the population distribution around the C5−C6 bond is essentially unaffected by substitution. None of the O2‘ hydroxyl groups of the β-d-glucopyranosyl residues in any of the disaccharides appear to be involved in inter-residue hydrogen bonding since 1JCH, 1JCC, and 2JCH values sensitive to C2‘−O2‘ rotamer distribution remain close to those observed in methyl β-d-glucopyranoside.
Place, publisher, year, edition, pages
2008. Vol. 112, no 14, 4447-4453 p.
IdentifiersURN: urn:nbn:se:su:diva-24631DOI: 10.1021/jp710977kISI: 000254659900041OAI: oai:DiVA.org:su-24631DiVA: diva2:197973
Part of urn:nbn:se:su:diva-72832008-01-102008-01-092010-07-14Bibliographically approved