Methyl 4-O-β-D-mannopyranosyl β-D-xylopyranoside

Methyl β-D-mannopyranosyl-(1→4)-β-D-xylopyranoside, C12H22O10, (I), crystallizes as colorless needles from water, with two crystallographically independent molecules, (IA) and (IB), comprising the asymmetric unit. The internal glycosidic linkage conformation in molecule (IA) is characterized by a φ′ torsion angle (O5′Man—C1′Man—O1′Man—C4Xyl; Man is mannose and Xyl is xylose) of −88.38 (17)° and a ψ′ torsion angle (C1′Man—O1′Man—C4Xyl—C5Xyl) of −149.22 (15)°, whereas the corresponding torsion angles in molecule (IB) are −89.82 (17) and −159.98 (14)°, respectively. Ring atom numbering conforms to the convention in which C1 denotes the anomeric C atom, and C5 and C6 denote the hydroxymethyl (–CH2OH) C atom in the β-Xylpand β-Manpresidues, respectively. By comparison, the internal glycosidic linkage in the major disorder component of the structurally related disaccharide, methyl β-D-galactopyranosyl-(1→4)-β-D-xylopyranoside), (II) [Zhang, Oliver & Serriani (2012).Acta Cryst.C68, o7–o11], is characterized by φ′ = −85.7 (6)° and ψ′ = −141.6 (8)°. Inter-residue hydrogen bonding is observed between atoms O3Xyland O5′Manin both (IA) and (IB) [O3Xyl...O5′Maninternuclear distances = 2.7268 (16) and 2.6920 (17) Å, respectively], analogous to the inter-residue hydrogen bond detected between atoms O3Xyland O5′Galin (II). Exocyclic hydroxymethyl group conformation in the β-Manpresidue of (IA) isgauche–gauche, whereas that in the β-Manpresidue of (IB) isgauche–trans.