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D ‐Galacturonsäurederivate, VI. D ‐Galacturonsäurederivate mit flüssigkristallinen Eigenschaften
Author(s) -
Vogel Christian,
Jeschke Udo,
Vill Volkmar,
Fischer Hartmut
Publication year - 1992
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.1992199201192
Subject(s) - chemistry , trifluoroacetic acid , alkyl , mesophase , molecule , chloride , nucleophile , polymer chemistry , organic chemistry , catalysis , phase (matter)
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.