Crystal structures of methyl 6-O-n-alkanoyl-β-d-glucopyranosides

The crystal structures of methyl 6-O-n-octanoyl-β-d-glucopyranoside 1 and methyl 6-O-n-decanoyl-β-d-glucopyranoside 2, which are types of glycosurfactants, were determined by X-ray analysis. Anhydrous crystals were obtained from a diethyl ether-acetone solution. The crystals are monoclinic, and the space group is P21 with Z = 2. The cell dimensions are as follows: 1, a = 7.760(1), b = 7.373(1), c = 15.514(1) Å, β = 102.91(1)°; 2, a = 7.724(1), b = 7.351(1), c = 16.957(2) Å, β = 94.81(1)°. The glucopyranoside moieties are in a 4C1 chair conformation and the conformation of the alkyl chain is the all-trans type. The molecules are arranged parallel to the a–c plane in a bilayer structure where alkyl chains are interdigitated. The sugar moieties are stacked to form a hydrophilic zone elongated parallel to the ab plane and arranged with a packing structure similar to that of methyl β-d-glucopyranoside in spite of a substituted long alkyl chain. Hydrogen bondings of sugar moieties are found only between the bilayers.