Glycopeptides synthesis on the solid phase

Glycopeptide Synthesis on the Solid Phase oAC5Neu(OMe)-(2-6)-aAc2GalNac... 

Using the automated stepwise method of synthesis on a solid phase allows the synthesis of polypeptides consisting of up to 120 amino acids. The final polypeptide is purified by HLPC (high pressure liquid chromatography). O-glycopeptides are also constructed on a solid phase using DCC and N-hydroxybenzotriazole in DMF. ... 

Polystyrene-based resins have been used successfully for the solid-phase synthesis of glycopeptides and oligosaccharides. Experiments that compare the rates of a reaction on a PS-resin compared to TentaGel have revealed that the rate of reaction completely depends on the nature of the reaction itself [36], Some reactions perform better on hydro-phobic resins, while others are better on hydrophilic resins. Another issue of particular importance for the synthesis of oligosaccharides on solid phase is the influence of the solid support on the stereochemical outcome of the reaction. There are few detailed studies that address this issue however, preliminary results are contradictory, but indicate that as in solution-phase reactions, the anomeric ratio is strongly influenced by the solvent, C-2 group on the donor and temperature [37-39]. In some cases there seems to be an enhancement of anomer selectivity on the solid phase [38]. 

Branched Homotrisaccharides.—The 0-serine glycoside of 0-p-D-Gl( -(l- 3)-0-[ 3-D-Glcp-(l- 6)]-D-Glcp has been synthesised in connection with studies on the solid phase synthesis of glycopeptides. ... 

Compared with O-glycopeptides, aecess to A-glycopeptides on the solid phase is more readily possible via two different pathways [42]—conventional sequential incorporation of preformed and suitably protected building blocks into the solid-phase synthesis or assembly of the peptide chain, selective removal of the aspartic acid side-chain protecting groups, and formation of the amide linkage between glycosyl amines and the peptide backbone [81] on the solid phase. 

For the solid-phase synthesis of glycopeptides, both polystyrene and PEG-based resins have been successfully used. Experiments that compare the rates of reactions on various resins have revealed that the rate of reaction completely depends on the nature of the reaction itself 45 Some reactions perform better on hydrophobic resins, while others are better on hydrophilic resins. 

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