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Amphiphilic sugar derivatives, formed by condensation of functionalized aliphatic chains with aldoses, form liquid crystals, in most cases smectic. A puzzling observation was the failure of the S,S-acetals of 6-deoxy sugars, L-rhamnose and D-fucose, to form such phases. A satisfactory model to explain this behavior involves-in most cases-the formation of columns, which are destabilized with the deoxy sugars in which the apolar end methyl groups are pushed together.Despite the abundance of chiral centers in the mono-and disaccharides used the smectic phases themselves in general display no chirality. By appropriate molecular design in which the amphiphilic character was deliberately suppressed it was possible to prepare glucose derivatives that exhibit chiral nematic phases as well as impressive helical twisting powers. Simple condensation chemistry is used to produce such derivatives.The amphiphilic character can be deliberately enhanced, and this is readily achieved in double headed 'gemini' derivatives formed by condensation of glucose or lactose with a long chain diamine followed by reduction followed by acylation of the nitrogen atoms with long chain acyl anhydrides. The thermodynamics of micellization of precursors to these derivatives have been studied. The gemini derivatives themselves display remarkable properties including the formation of giant vesicles and an appreciable capacity for the solubilization of hydrocarbons.

Reliable method for the synthesis of aryl β-D-glucopyranosides, using boron trifluoride-diethyl ether as catalyst Smits, Elly; Engberts, Jan; Kellogg, Richard M.; Doren, Henk A. van Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Stereospecific formation of aryl 2,3,4,6-tetra-O-acetyl-β β-D-glucopyranosides was achieved by reaction of penta-O-acetyl-β β-D-glucose 1 with substituted phenols in the presence of boron trifluoride. Yields of the purified products varied from 52-85%. Benzyl alcohol could also be glucosylated using similar conditions. All products were purified by crystallization from ethanol. The purity and the anomeric configuration of the products were determined by means of 1 H and 13 C NMR spectroscopy, melting points and optical rotation.

For the production of a commercially useful dye extract from madder, the glycoside ruberythric acid has to be hydrolysed to the aglycone alizarin which is the main dye component. An intrinsic problem is the simultaneous hydrolysis of the glycoside lucidin primeveroside to the unwanted mutagenic aglycone lucidin. Madder root was treated with strong acid, strong base or enzymes to convert ruberythric acid into alizarin and the anthraquinone compositions of the suspensions were analysed by HPLC. A cheap and easy method to hydrolyse ruberythric acid in madder root to alizarin without the formation of lucidin turned out to be the stirring of dried madder roots in water at room temperature for 90 min: this gave a suspension containing pseudopurpurin, munjistin, alizarin and nordamnacanthal. Native enzymes are responsible for the hydrolysis, after which lucidin is converted to nordamnacanthal by an endogenous oxidase.