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The (2-azidomethyl)phenylacetyl group (AMPA) is described as a new protecting group for carbohydrates. AMPA was introduced to carbohydrate hydroxyl groups in the presence of DCC, while its removal was conveniently achieved via Lindlar catalyst-catalyzed hydrogenation that had no influence on other protecting groups including benzyl, acyl, acetal and ketal.

Four glycolipids carrying different glycans and a nitroxide free radical spin at the glycan non-reducing end were designed and synthesized from free glucose and maltooligosaccharides by an efficient and streamlined synthetic strategy. The main features of this synthetic strategy include regioselective functionalization of the free carbohydrates and coupling of the radical spin label with functionalized free glycans as the last synthetic step. These glycolipids are useful probes for the study of cell surface glycans by electron paramagnetic resonance spectroscopy. Moreover, the key synthetic intermediates, free glycolipids carrying a flexible azido group at the glycan non-reducing end, are widely useful platforms for accessing glycolipids with other molecular labels. [ABSTRACT FROM AUTHOR]

Research has been conducted on N-glycopeptides. The authors report that the synthesis of these compounds which contain trisaccharide chains has been carried out via the use of glycosylated Fmoc-asparagine as a key building block.

Trialkylsilane-mediated reductive etherification has been actively used in carbohydrate O-benzylation since it emerged decades ago. In this review, we first trace the origin, development, and possible reaction mechanism of trialkylsilane-mediated reductive etherification, then focus on its typical applications in carbohydrate synthesis including regioselective protection, one-pot combinatorial protection, and one-pot protection-glycosylation. At the end, we discuss its limitations and potentials in global benzylation. [ABSTRACT FROM AUTHOR]

Burkholderia multivorans is a Gram-negative bacterium, and an important opportunistic human pathogen that can cause fatal infections. Its O-antigens are useful templates for the development of carbohydrate-based vaccines. A highly convergent and efficient strategy was developed for the synthesis of tri-, hexa-, and nonasaccharide fragments of the O-antigen of B. multivorans species Y. In these syntheses, a trisaccharyl thioglycoside, which was assembled from thiomannoside acceptor and rhamnosyl and mannosyl trichloroacetimidate donors, was used as a key building block. Glycosylation of 3-azidopropanol with the trisaccharyl donor followed by global deprotection gave the target trisaccharide. The trisaccharyl donor was also used to elongate the carbohydrate chain to obtain the dimer and trimer in a [3 + 3] and [3 + 3 + 3] manner. All of the synthetic targets have a free amino group at their reducing end to facilitate further derivatization, such as conjugation with other functional biomolecules. [ABSTRACT FROM AUTHOR]

Glycosylphosphatidylinositol (GPI) anchoring of proteins to the cell surface is important for various biological processes, but GPI-anchored proteins are difficult to study. An effective strategy was developed for the metabolic engineering of cell-surface GPIs and GPI-anchored proteins by using inositol derivatives carrying an azido group. The azide-labeled GPIs and GPI-anchored proteins were then tagged with biotin on live cells through a click reaction, which allows further elaboration with streptavidin-conjugated dyes or other molecules. The strategy can be used to label GPI-anchored proteins with various tags for biological studies. [ABSTRACT FROM AUTHOR]

β-Glucans are important carbohydrate antigens that are found on the surface of fungal cells, and they could be useful for the development of antifungal vaccines. This paper describes a highly convergent and efficient strategy for the synthesis of structurally defined branched β-glucan oligosaccharides that can be used for detailed studies of β-glucans and for the design of β-glucan-based vaccines. The strategy was highlighted by assembling three target compounds through preactivation-based glycosylation with thioglycosides as glycosyl donors. It was used to successfully prepare β-glucan oligosaccharides consisting of a β-1,3-linked nonaglucan backbone linked to a β-1,6-glucotetraose, a β-1,3-glucodiose, or a β-1,3-glucotetraose branch at the 6- O-position of the nonaglucan central sugar unit. The structure and size of the glycosyl donors and acceptors used in the syntheses did not significantly affect the efficiency of the glycosylation, which suggests that this strategy can be generally useful for the synthesis of more complex structures. [ABSTRACT FROM AUTHOR]

Tumor-associated carbohydrate antigens (TACAs) are important molecular markers on the cancer cell surface, useful for the development of therapeutic cancer vaccines or cancer immunotherapies. However, because of their poor immunogenicity and/or immunotolerance, most TACAs fail to induce T cell-mediated immunity that is critical for cancer therapy. This review summarizes the recent effort to overcome this problem via constructing TACA conjugates with improved immunogenicity, such as by covalently coupling TACAs to proper carrier molecules to form clustered or multi-epitopic conjugate vaccines, coupling TACAs to a T cell peptide epitope and/or an immunostimulant epitope to form fully synthetic multi-component glycoconjugate vaccines, and developing vaccines based on chemically modified TACAs, which is combined with metabolic engineering of cancer cells. [Copyright &y& Elsevier]

The carbohydrate core of amipurimycin in its fully acetylated form was synthesized in 24 steps starting from commercially available methyl 4,6-O-benzylidene-α-D-glucopyranoside to give an overall yield of 1.5%. The late-stage intermediates involved were suitable for total synthesis of amipurimycin. It was further discovered that the branches and the protecting groups on the sugar rings of involved intermediates had a significant influence on their conformations, which in turn resulted in new and interesting cyclization reactions. [ABSTRACT FROM AUTHOR]

MUC1 glycopeptide was efficiently coupled to glycosylphosphatidylinositol (GPI) derivatives by sortase A (SrtA), verifying that SrtA can accept sterically hindered glycopeptide as substrate for ligation with GPIs. This work has established a practical method for the chemoenzymatic synthesis of GPI-linked glycopeptides. [ABSTRACT FROM AUTHOR]

An efficient synthesis of a derivative of monophosphoryl lipid A suitable for coupling to various structures for the construction of glycoconjugate vaccines and its conjugation with an N-modified form of the tumor-associated antigen GM3 is presented. [ABSTRACT FROM AUTHOR]

In this article, the authors focus on a research published in the journal "Current Organic Synthesis" in 2013 related to the glycosylphosphatidylinositol (GPI) anchors and GPI-anchored glycopeptides, peptides and proteins.

Review: 146 refs. [ABSTRACT FROM AUTHOR]

A derivative of the tumor-associated globo H antigen, a complex hexasaccharide, is synthesized by convergent and efficient [3+2+1] strategy using various glycosylation methods. [ABSTRACT FROM AUTHOR]