Oligosaccharide using soluble resins

Considerable effort has been made in recent years to improve the yields of oligosaccharide synthesis. The selection of the appropriate functional resin is, in many cases, crucial to the outcome of oligosaccharide syntheses. Here, we briefly review the functional resins that have been used for oligosaccharide synthesis. The chapter is divided into two main sections First the most common insoluble and soluble resins applied in oligosaccharide synthesis are reviewed and then the different types of linkers applied in oligosaccharide synthesis are summerized. Two subsections are dedicated to ionic liquids (Section 20.3.3), representing a special case of soluble resins , and magnetic parhcles (Section 20.2.3), which are considered a relatively new concept of insoluble solid supports. 

This book covers all of the most recent (at the time of writing) developments in the field of solid support oligosaccharide synthesis. Included are chapters discussing different synthetic strategies, glycosylation protocols, the use of solid supports versus soluble polymeric supports and on-resin analytical methods. Special topics such as the formation of [3-glycosidic linkages on solid support are also discussed. 

Recall from Chapter 23.2.4 that humic substances are isolated from seawater by adsorption on a hydrophobic resin followed by elution using solvents of varying pH. The desorbed compounds are fractionated into two classes, humic acids fulvic acids based on their solubility behavior. A model structure for a humic acid is illustrated in Figure 23.10a in which fragments of biomolecules, such as sugars, oligosaccharides. 

Nonlinear, dendritic or hyperbranched polymers have received considerable attention in recent years. These polymers have seen little use as supports for oligosaccharide synthesis compared to Merrifield or soluble MPEG resins. Nevertheless, some interesting applications of hyperbranched polymers such as hyperbranched polyester and poly(amidoamine) to oligsaccharide synthesis have been reported. 

The acceptor-bound strategy permits more reactive building blocks, because decomposition of the donor results in soluble by-products that can be washed away from the resin-bound oligosaccharide. This strategy was ultimately used for automation. 

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