98600-45-4Relevant articles and documents
Synthesis of Some Deuterated Aromatic Mesomorphic Compounds Used in Broad-Line 2H-NMR Studies
Neubert, Mary E.
, p. 327 - 374 (2007/10/02)
Twenty-one deuterated mesogens of the following types: HOAB (perdeuterated chains), 4-alkoxybenzoic acids (perdeuterated chain and acid deuteron), 7S5 and 8S5 (perdeuterated alkoxy chain), 4-alkoxybenzylidene-4'-alkylanilines (2 or 4 deuterons in the aniline ring, 2-α-deuterons on the alkyl chain and perdeuterated alkyl or alkoxy chain) and TBBA (perdeuterated alkyl chains or anil deuterons) were prepared for use in broad-line 2H-NMR by using standard literature methods.The required 4-alkoxybenzoic acids, aldehydes and anilines with perdeuterated chains were prepared by alkylation of the appropriate 4-substituted phenol.The acid proton in the 4-alkoxybenzoic acids were replaced with a deuteron either by basic hydrolysis of the ester or acid chloride or by base-catalyzed exchange on the acid.Two deuterons were incorporated into the aniline ring ortho to the amino group by exchange in dilute H2SO4.Four ring deuterons, two α-chain deuterons or a perdeuterated chain were incorporated into 4-alkylanilines by the following sequence of steps: Friedel-Crafts acylation of benzene with an acid chloride, catalytic reduction, Friedel-Crafts acylation with oxalyl chloride, hydrolysis in base and a Schmidt rearrangement in H2SO4.New deuteration equipment was designed for the catalytic reduction using deuterium.IR NMR and MS were used to determine the deuterium content of these compounds.Small differences in mesophase transition temperatures were observed for mesogens containing perdeuterated alkyl or alkoxy chains.
