D ‐Galacturonsäurederivate, VI. D ‐Galacturonsäurederivate mit flüssigkristallinen Eigenschaften

D ‐Galacturonic Acid Derivatives, VI. — D ‐Galacturonic Acid Derivatives with Liquid Crystalline Properties Esters, thioesters, and amides of D ‐galacturonic acid have been synthesized from alcohols, thioalcohols, and amines having long alkyl chains. Key intermediate of the reaction with the different nucleophiles was the 1,2;3,4‐di‐ O ‐isopropylidene‐α‐ D ‐galactopyranuronosyl chloride ( 3 ). Deisopropylidenation of the protected esters, thioesters, and amides was achieved by trifluoroacetic acid. The investigation of the liquid crystalline properties was carried out with a polarizing microscop, DSC measurements, and X‐ray diffraction. Molecules with three long alkyl chains can be obtained by reaction of amides 5h and 5i with thioalcohols. MM2 calculations voted a Y‐shaped structure of the mercaptals 8a and 8b which do exhibit thermotropically a columnar hexagonal mesophase (D hd ) as we have proved by X‐ray diffraction.