Takuro Ako

Single‐Step Multisyntheses of Glycosyl Acceptors: Benzylation of n‐1 Hydroxyl Groups of Phenylthio Glycosides of Xylose, Mannose, Glucose, Galactose, 2‐Azido‐2‐deoxy‐glucose, and 2‐Azido‐2‐deoxy‐galactose

An array of synthons is required to access an oligosaccharide library; however, multistep and thus time‐consuming synthesis is inevitable. To rapidly access such synthetic units, multiple benzylation reactions of monosaccharides under phase‐transfer conditions were examined. Multiple benzyl groups were successfully incorporated in one step, especially in the cases of reactions with triol systems.

Energy-Resolved Structural Details Obtained from Gangliosides

Gangliosides, a family of glycosphingolipids (GSLs) that comprise sialic acid residue(s), are an important class of molecules that exist on the outer surface of the plasma membrane. To assess the functions of a particular series of gangliosides that play important roles in brain functions, their structures and localizations need to be investigated. We studied the structures of these gangliosides by collision-induced dissociation using quadrupole ion-trap mass spectrometry. The dissociation processes were investigated in detail based on energy-resolved mass spectrometry using sodiated molecules. The decision of utilization of the positive mode was based on the assumption that it was the generally applicable method for GSLs, including neutral ones. In this investigation, sialic acid residues were esterified to stabilize the linkages and to generate multiple fragment ions for successful structural investigations. A detailed analysis of a series of sodiated species of gangliosides based on energy-resolved mass spectrometry revealed that the GM1-equivelent fragments generated from the precursor ions under low energy CID conditions had the structural characteristics of their individual precursors. It was suggested that this information will be useful in determining the structures of their precursor gangliosides.

Stationary Solid-Phase Reaction (SSPR) for Oligosaccharide Synthesis

Synthetic methods to access oligosaccharide structures are extremely important to provide bio-probes for the functional analysis. Furthermore, a combinatorial oligosaccharide library is potentially important in terms of diagnoses and providing potential seeds for new pharmaceuticals.