Glycosylated foldamers: synthesis of carbohydrate-modified β3hSer and incorporation into β-peptides

Solid-Phase O-Glycosylation with a Glucosamine Derivative for the Synthesis of a Glycopeptide

An efficient synthesis of the O-linked glycosylamino acid Fmoc–l-Ser((Ac)3–β-d-GlcNAc)-OH building block is described. The utility of the method was demonstrated with direct solid-phase O-glycosylation of the hydroxyl group on the amino acid (Ser) side chain of a human α-A crystallin-derived peptide (AIPVSREEK) in nearly quantitative glycosylation yield.

Synthesis of glycosylated β³-homo-threonine conjugates for mucin-like glycopeptide antigen analogues

Glycopeptides from the mucin family decorated with tumour-associated carbohydrate antigens (TACA) have proven to be important target structures for the development of molecularly defined anti-cancer vaccines. The strategic incorporation of β-amino acid building blocks into such mucin-type sequences offers the potential to create pseudo-glycopeptide antigens with improved bioavailability for tumour immunotherapy. Towards this end, T(N) and TF antigen conjugates O-glycosidically linked to Fmoc-β³-homo-threonine were prepared in good yield via Arndt-Eistert homologation of the corresponding glycosyl α-amino acid derivative. By incorporation of T(N)-Fmoc-β³hThr conjugate into the 20 amino acid tandem repeat sequence of MUC1 using sequential solid-phase glycopeptide synthesis, a first example of a mixed α/β-hybrid glycopeptide building block was obtained. The latter is of interest for the development of novel glycoconjugate mimics and model structures for anti-cancer vaccines with increased biological half-life.