Synthesis, purification and liquid-crystalline behaviour of several alkyl 1-thio-d-glycopyranosides
作者:Saskia A. Galema、Jan B.F.N. Engberts、Henk A. van Doren
DOI:10.1016/s0008-6215(97)00185-7
日期:1997.10
This paper describes the synthesis, purification, and liquid-crystalline behaviour of a series of alkyl 1-thioglycopyranosides. The synthesis of these derivatives was carried out via a Lewis acid mediated coupling of the fully acetylated monosaccharide with an alkanethiol. The choice of the Lewis acid depends on the configuration of AcO-2, The carbohydrate-derived surfactants exhibit thermotropic liquid-crystalline behaviour. The alkyl 1-thioglycopyranosides form the expected smectic A phases upon heating. The clearing temperatures vary with alkyl chain length which is in accordance with the accepted model for the S-A phase of amphiphilic carbohydrate mesogens. For the alkyl 1-thiotalopyranosides, the clearing points are much lower than expected, presumably due to the formation of an intramolecular hydrogen bond in the talose moiety. (C) 1997 Elsevier Science Ltd.