title: Crystal and molecular structure of methyl O-alpha-D-manno-pyranosyl-(1----2)-alpha-D-mannopyranoside.
abstract: The crystal and molecular structure of a synthetic mannosyl disaccharide, methyl O-alpha-D-mannopyranosyl-(1----2)-alpha-D-mannopyranoside, has been determined from X-ray diffractometer data by direct methods by use of the Multan programs. The crystals are monoclinic, space group P2 with unit cell dimensions, a 8.086(1), b 9.775(1), c 9.975(2) A, beta 104.58(1) degrees, Z 2, and Dm 1.54 g/cm3. The structure was refined to an R-value of 0.033 for 1359 reflections measured with CuK alpha radiation. The mannopyranose units have the chair conformations 4C(D) with C-5' and C-2' deviating from the best plane through the other four atoms of the ring by -0.68 and +0.53 A in the nonreducing group, and C-3 and O-5 deviating from the mean plane through the other four atoms by +0.57 and -0.66 A, respectively, in the "potentially" reducing residue. The ring-to-ring conformation can be described as (phi, psi) = (-64.5, 105.5 degrees). The conformation across the C-5--C-6 bond is gauche-gauche in both the sugars. The crystal structure is stabilized by a network of intermolecular O-H...O hydrogen bonds.
authors.affiliation: Center for Crystallographic Research, Roswell Park Memorial Institute, Buffalo, New York 14263.
authors.forename: T
authors.initials: T
authors.lastname: Srikrishnan
authors.forename: M S
authors.initials: MS
authors.lastname: Chowdhary
authors.forename: K L
authors.initials: KL
authors.lastname: Matta
mesh_terms: D002236:Carbohydrate Conformation; D003460:Crystallization; D004187:Disaccharides; D006860:Hydrogen Bonding; D015394:Molecular Structure; D014961:X-Ray Diffraction
chemical_list: D004187:Disaccharides