Molecular and crystal structures of 2,3,4,6,1′,3′,4′,6′-octa-O-acetyl-β-sophorose, methyl 2,3,4,6,3′,4′,6′-hepta-O-acetyl-β-sophoroside, and methyl 2,3,4,6,3′,4′-hexa-O-acetyl-6′-deoxy-β-sophoroside

The molecular and crystal structures of 2,3,4,6,1′,3′,4′,6′-octa-O-acetyl-β-sophorose (β-sophorose octaacetate), methyl 2,3,4,6,3′,4′,6′-hepta-O-acetyl-β-sophoroside (methyl β-sophoroside heptaacetate), and methyl 2,3,4,6,3′,4′-hexa-O-acetyl-6′-deoxy-β-sophoroside (methyl 6′-deoxy-β-sophoroside heptaacetate) were determined by X-ray diffraction. All structures were obtained by the direct method and refined by the full-matrix least-squares procedure. The crystal data and final R values are as follows: (β-sophorose octaacetate, C28O19H38, monoclinic, P21, a = 15.529(4), b = 10.958(2), c = 10.804(2) Å, β = 107.73(3)°, Dobsd = 1.285 g cm−3, Dcalcd = 1.288 g cm−3, Z = 2, R = 0.052, RW = 0.052; methyl β-sophoroside heptaacetate, C27O18H38, orthorhombic, P212121, a = 20.992(5), b = 27.642(7), c = 5.730(2) Å, Dobsd = 1.305 g cm−3, Dcalcd = 1.295 g cm−3, Z = 4, R = 0.064, RW = 0.066; methyl 6′-deoxy-β-sophoroside hexaacetate, C25O16H36, hexagonal, P65, a = b = 15.136(2), c = 23.534(4) Å, Dcalcd = 1.264 g cm−3, Z = 6, R = 0.079, RW = 0.064. All the d-glucose residues have the 4C1 pyranose conformation. These three molecules interact with their surrounding molecules by van der Waals forces, only. Conformational angles of φ and ω at the β (1 → 2) glycosidic linkage of these compounds are similar to each other and close to the energetically minimum positions. All the primary acetate substituents at C-6 take a gauche-gauche conformation.