O-glyco side

Ponticelli, F. Trendafilova, A. Valoti, M. Saponara, S. Sgaragli, G. Synthesis and anti-peroxidant activity of new phenolic O-glyco-sides. Carbohydr. Res. 2001, 330, 459-468. 

The position of the sugar residue in the dihydroindole portion can be determined by methylation of the pigment with diazomethane and subsequent alkaline degradation of the resulting neobetanin derivative. In the case of 5-0-glycosides, 5-hydroxy-6-methoxyindole-2-carboxylic acid is obtained, whereas the 6-O-glyco-sides yield 6-hydroxy-5-methoxyindole-2-carboxylic acid (47,48). The indole carboxylic acids are easily identified by TIjC. 

Kite GC, Veitch NC. Identification of common glycosyl groups of flavonoid O-glyco-sides by serial mass spectrometry of sodiated species. Rapid Commun Mass Spectrom. 2011 25 2579-90. 

Cellulose consists of several thousand o-glucose units linked by l- 4-/3-glyco-side bonds like those in cellobiose. Different cellulose molecules then interact to form a large aggregate structure held together by hydrogen bonds. 

FIGURE 3.8 a-o-glyco-linkage (1) and a-o-glyco- and malto-sylated aromasic hydroxy side chain of Tyr-194 (2). 

Since Kishi reported allylation of glycosyl / -nitrobenzoate with allyltrimethylsilane in the presence of a Lewis acid (entry 1 in Table 4) [ 19c], a variety of leaving groups such as halogen, ester, ether, imidate, and phosphate have been employed. Typical examples are shown in O Table 4, indicating the generality of this method for the synthesis of a-allyl-C-glyco-sides [29]. 

Fig. I6A A methanoiic extract of Lespedezae herba (4) contains more highly glycosidated flavonoids (R, range 0.05-0.35) such as kaempferol- and/or isorhamnetin-rhamno-glucoside and rutin (Tl). The EtAc extract (5,6) contains the enriched yellow zones of flavon-C-glyco.sides such as isoorientin (R, -- 0.S/T3), orientin (R, — 0.65/T3) overlapped by isovitexin, a.s well as flavonol-O-glycosides such as lespedin, hyperoside, isoquerdtrin and querdtrin (Rf 0.6-0.8).

Fig. I9A Extracts from trade samples Virgaureae or Solidaginis herba (1-3), show three t o four orange or yellow-green quercetin and kaempferol glyco.sides in varying concentrations in the R, range 0.4-0.75 quercetin and/or kaempferol rutino.side (R, 0.4/Tl),...

Likewise, activated aromatic compounds give mainly -linked aryl C-glyco-sides from tri-O-acetyl-D-glucal (1) in the presence of Lewis acids, presumably because the bulky aryl groups can attain the favoured -equatorial orientation by isomerization via acyclic C-1 carbenium ions which are stabilized by both the allylic and aryl rr-systems [44]. 

Glycochemistry is an important science, particularly for the synthesis of complex carbohydrates which play key roles in several biological events. Phenyl 1-thio-glyco-sides in particular and related thioglycosides have been used extensively for the synthesis of complex oligosaccharides. Moreover, aryl l-thio-P-o-galactopyranosides have been nsed recently as specific inhibitors of human galectins. ... 

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