Crystal and molecular structures of derivatives formed by reaction between toluenesulfonhydrazide and D-glucose, D-galactose, and L-arabinose

Derivatives formed by reaction of toluenesulfonhydrazide with D-glucose, D-galactose, and L-arabinose are shown by X-ray crystal structure analysis to be N-glycosides rather than open-chain hydrazones in the solid state. All three sugar derivatives assume the ⁴C₁ pyranosyl form, and in all three cases the orientation of the N-glycosidic linkage is equatorial. The gauche conformation of the glucoside and galactoside at the N(2)–N(1)–C(1)–C(2) linkage allows formation of an intramolecular hydrogen bond between the O(2) hydroxyl group and a sulfonyl oxygen atom, but no corresponding intramolecular interaction is found in the arabinoside due to its trans conformation at this linkage. In both the galactoside and arabinoside an S–O bond is eclipsed with the phenyl ring, but in the glucoside the phenyl ring assumes a staggered orientation with respect to the S–O bonds. Intermolecular hydrogen bonding interactions bind the molecules together to form alternating layers of hydrophilic groups (the pyranosyl rings) and hydrophobic groups (the aryl rings) in the crystal.