N-Fucose

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... 

Sugars with 0-benzyl substituents can be oxidized to the corresponding aldonic acid. The oxidation of 2-0-benzyl-n-fucose to 2-0-benzyl-n-fuconic... 

The synthesis of 2-methyl-n-fucose was carried out first directly from D-fucose. Methylation of methyl 3,4-isopropylidene-D-fucopyranoside (XI) and hydrolysis of the glycosidic methyl group in the product (XII) led directly to the desired sugar (XIII). 

D-Arabinose, L-galactose, n-fucose, and possibly L-glucose also occur in nature. The physical properties of these sugars and their derivatives are identical with those of the corresponding enantiomorphs listed above except for the sign of the optical rotation. 

Kabat has proposed that the side chains that are removed first during acid treatment hang from the linear polymer. The side chains consist of n-fucose-containing oligosaccharides and impart blood group specificity. If thia ia true, the chemical constitution of blood group substances would be reduced to a modification of the ground substance. 

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