Synthesis of protected precursors of chitin oligosaccharides by electrochemical polyglycosylation of thioglycosides

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2021-2022

The use of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry for the analysis of carbohydrates and glycoconjugates is a well-established technique and this review is the 12th update of the original article published in 1999 and brings coverage of the literature to the end of 2022. As with previous review, this review also includes a few papers that describe methods appropriate to analysis by MALDI, such as sample preparation, even though the ionization method is not MALDI. The review follows the same format as previous reviews. It is divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of computer software for structural identification. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other general areas such as medicine, industrial processes, natural products and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. MALDI is still an ideal technique for carbohydrate analysis, particularly in its ability to produce single ions from each analyte and advancements in the technique and range of applications show little sign of diminishing.

Recent advancements in synthesis of cyclic oligosaccharides

The development of synthetic methods for chemical glycosylation enables the synthesis of various oligosaccharides, including nonnatural cyclic oligosaccharides. Electrochemical glycosylation is an enabling technology not only for automated solution-phase synthesis of linear oligosaccharides but also for the chemical synthesis of cyclic oligosaccharides. In this review, recent syntheses of nonnatural cyclic oligosaccharides are also introduced, and glycosylation methodologies are focused on.

Synthesis of cyclic β-1,6-oligosaccharides from glucosamine monomers by electrochemical polyglycosylation

The synthesis of protected precursors of cyclic β-1,6-oligoglucosamines from thioglycosides as monomers is performed by electrochemical polyglycosylation. The monomer with a 2,3-oxazolidinone protecting group afforded the cyclic disaccharide exclusively. Cyclic oligosaccharides up to the trisaccharide were obtained using the monomer with a 2-azido-2-deoxy group.

Towards one-pot selective synthesis of cyclic oligosaccharides

In this chapter are described electrochemical routes to cyclic oligosaccharides. While automated electrochemical methods have been used to prepare linear oligosaccharides, their conversion to cyclic oligosaccharides proved to be a complex process. The concept of polyglycosylation offers an interesting alternative, and the process which has been developed is that of a one-pot electrochemical polyglycosylation-isomerization-cyclization (ePIC) process.