Fucoside methyl

The latter was isolated in the form of fully methylated methyl fuco-side, i. e., methyl 2,3,4-trimethyl-a-L-fucoside (XLVII), a compound previously obtained from methylated gum tragacanth.128 The recognition of this particular derivative indicates that the n-fucose residues in part at least must constitute end groups linked glycosidically to the rest of the molecule. The same compound128 was isolated by methylation and... 

Conchie and Percival97 found that the direct methylation of fucoidin with dimethyl sulfate and sodium hydroxide was more satisfactory than the simultaneous deacetylation and methylation of its acetyl derivative. Methylated fucoidin was hydrolyzed and the products were converted to their methyl glycosides. By chromatography on alumina there were isolated methyl L-fucosides (about 20%), methyl 3-methyl-L-fucosides (57%) and methyl 2,3-dimethyl-L-fucosides (20%). 

Other partially protected carbohydrates also undergo very regioselective oxidation. Noteworthy is the oxidation of isopropylideneglucofuranose 29 to 5-ketofuranose 30 (O Scheme 10) [109]. For oxidation of the axial hydroxy group in cis-1,2 diols, the dibutylstannylene acetal method is often employed. Oxidation of methyl fucoside 31 with this procedure gives ketone 32 in good yield (O Scheme 10) [111]. 

Takaichi S, Maoka T, Masamoto K (2001) Myxoxanthophyll in Synechocystis sp. PCC 6803 is myxol 2 -dimethyl-fucoside, (31 ,2 S)-myxol 2 -(2,4-di-0-methyl-a-L-fucoside), not rhamnoside. Plant Cell Physiol 42 756-762... 

Highly porous and hydrophilic supports have been prepared by co-polymerization of A-tris(hydroxymethyl)methyl acrylamide or A-tris(hydroxymethyl)-methyl methacrylamide with acrylic monomers bearing carboxyl functions, and then treated with 4-aminophenyl a-L-fucoside using a water-soluble carbodi-imide mediator. The support was used for purification of the L-fucose-binding lectin from Ulex europeus. 

The regioselectivity of the butanoylation of methyl a-L- and a-D-rhamnoside and fucoside has been examined. Lipase catalysed transesterification from 2,2,2-trifluoroethyl butanoate in THF gave the 4-monoesters in >70% yield from the L-glycosides, while the D-... 

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