The crystal and molecular structure of methyl 2,4,6-tri-O-acetyl-3-O(2,3,4,6-Tetra-O-acetyl-β-d-glucopyranosyl)-β-d-glucopyranoside (methyl 2,3,4,6,2′,4′,6′,-hepta-O-acetyl-β-d-laminarabioside)

The crystal and molecular structure of methyl 2,3,4,6,2′,4′,6′-hepta-O-acetyl β-laminarabioside has been determined by X-ray diffraction. The crystal belongs to the orthorhombic system space group P2₁2₁2₁,a 10.471 (1), b 22.482(1), c 13.647(1) Å, D_m 1.33 g.cm^?3, Z 4. The structure was established by the direct method and refined by the block-diagonal, least-squares procedure to R 0.093 for 2043 observed reflections. Difference synthesis showed all the hydrogen atoms except the methyl hydrogen ones. The molecule shows a fully-extended conformation and has no intra-molecular hydrogen bond. The ring-to-ring conformation can be described.as (φψ)  (42.5, 4.7°), according to the definition of Sathyanarayana and Rao, and it is compared with (φψ)  (27.9, ?37.5°) of laminarabiose. There is no inter-molecular hydrogen bond. The d-glucopyranose rings of the molecule are piled up along the a axis and approximately parallel to the bc-plane. Each of the acetyl groups is approximately perpendicular to the d-glucopyranose ring.