Liquid-crystal properties of octyl 6′-O-alkylmelibiosides

6-O-α-d-Galactopyranosyl-d-glucopyranose (melibiose) derivatives with alkyl groups at the terminal 1-O and 6′-O positions have been synthesized. They show thermotropic and lyotropic liquid-crystal properties. The d-spacings of the strong inner X-ray diffraction rings correspond to ∼ 0.9 times the extended length of the molecule. The molecules are therefore either extended in monomolecular layers or U-shaped in bimolecular layers.