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Glycoconjugates amine

For conversion of amide to other acid derivatives, a novel synthesis of urea glycosides in aqueous media has been reported via the reaction of Steyermark s glucosyl carbamate with amines in good yields (Eq. 9.17).38 This method was successfully applied to develop a new route to the synthesis of urea-tethered neo-glycoconjugates and pseudooligosaccharides. [Pg.308]

Polysaccharides, glycoproteins, and other glycoconjugates therefore may be specifically labeled on their carbohydrate portions by creating aldehyde functionalities and subsequently derivatizing them with another molecule containing an amine or a hydrazide group. This route of derivatization is probably the most common way of modifying carbohydrates. [Pg.42]

This simple strategy can be used to add amine residues to polysaccharide molecules after formation of aldehydes by periodate or enzymatic oxidation (Section 4.4, this chapter). Thus, glycoconjugates or carbohydrate polymers such as dextran may be derivatized to contain amines for further conjugation reactions. [Pg.125]

Figure 5.35 ABH reacts with aldehyde-containing compounds through its hydrazide end to form hydrazone linkages. Glycoconjugates may be labeled by this reaction after oxidation with sodium periodate to form aldehyde groups. Subsequent photoactivation with UV light causes transformation of the phenyl azide to a nitrene. The nitrene undergoes rapid ring expansion to a dehydroazepine that can couple to nucleophiles, such as amines. Figure 5.35 ABH reacts with aldehyde-containing compounds through its hydrazide end to form hydrazone linkages. Glycoconjugates may be labeled by this reaction after oxidation with sodium periodate to form aldehyde groups. Subsequent photoactivation with UV light causes transformation of the phenyl azide to a nitrene. The nitrene undergoes rapid ring expansion to a dehydroazepine that can couple to nucleophiles, such as amines.
Carboxymethyl glycoside lactones are easily prepared by diverse routes and react readily with nucleophilic species. Their reaction with amines, a simple addition which does not require any intermediate activation, is very general, and many examples of new pseudo-glycoconjugates prepared by this method are described. Moreover, 1,2-bisfunctionalized carbohydrate systems are efficiently constructed by reaction of the free OH on position 2 obtained after the opening of the lactone ring. Applications at the frontier of materials and biology have been envisaged and further studies in these fields will be reported in the near future. [Pg.120]

Prieels et al. (1976) studied the binding of glycoconjugates with galactosyltransferase in both the presence and absence of a-lactalbumin. They concluded that, in contrast to its ability to inhibit AT-acetyllactos-amine production, a-lactalbumin does not inhibit the transfer of d-galactose to oligomers of A -acetylglucosamine or to glycopeptides. [Pg.257]

The direct introduction of active groups on the polysaccharide and the protein could seriously affect the efficiency of the coupling by steric hindrance [114]. By direct attachment, the saccharide epitopes could be shielded by the secondary structure of the protein. To avoid this problem, a spacer arm is frequently introduced either on the modified CPS or on the protein carrier during the design of a glycoconjugate. The conjugates represented in Scheme 4 have been shown to be highly stable. They contained aliphatic amines [115], amides [116,117], or thioethers [118]. [Pg.2713]


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See also in sourсe #XX -- [ Pg.11 , Pg.912 ]




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Glycoconjugate

Glycoconjugates

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