The synthesis and mesogenic behaviour of the first series of low molar mass thieno[3,2-b]thiophene-2-carboxylate ester-based mesogens

Abstract

Seed (2009) The synthesis and mesogenic behaviour of the first series of low molar mass thieno[3,2-b]thiophene-2-carboxylate ester-based mesogens, Liquid Crystals, 37:1, 101-108,The synthesis of a family of alkyl 5-(4-hexyloxyphenyl)thieno[3,2-b]thiophene-2-carboxylate liquid crystals is described. The synthetic methodology utilised includes a Fiesselmann synthesis of the thieno[3,2-b]thiophene core, and the first report of a completely regioselective a-bromination of the resulting thieno[3,2-b]thiophene-2-carboxylate ester. The target materials display enantiotropic smectic A phases with melting points and transition temperatures that are significantly higher than their phenyl analogues. The synthesis and mesomorphic behaviour of these new materials is reported and discussed.

Low molar mass thieno[3,2-b] and thieno[2,3-b]thiophenes in liquid crystal materials science: recent synthetic approaches

“…[13] This paper represented the first in a series of structure-property studies to evaluate whether the thienothiophene cores were capable of supporting tilted smectic phases and/or the nematic phase.…”

Preparation of Brominated 2-Alkoxythiophenes via Oxidation and Etherification of 2-Thienyltrifluoroborate Salts

“…Formylation of 3c with LDA and N -formylpiperidine afforded 4 in excellent yield (92%). Exploiting our recently reported method for thienothiophene synthesis, we treated aldehyde 4 with nonyl mercaptoacetate 5 in the presence of base at 65 °C, affording thienothiophene 6 in good yield (86%) via a tandem nucleophilic aromatic substitution and aldol condensation reaction (we saw no difference in the two-step yield whether or not intermediate 4 was purified).…”