Total synthesis of theHelicobacter pyloriserotype O2 O-antigen α-(1 → 2)- and α-(1 → 3)-linked oligoglucosides

Abstract

Unique α-(1 → 2)- and α-(1 → 3)-linked oligoglucosides from the H. pylori serotype O2 O-antigen were synthesized with exclusive α-selectivity using remote participation effects.

Convergent Chemoenzymatic Strategy to Deliver a Diversity of Shigella flexneri Serotype-Specific O-Antigen Segments from a Unique Lightly Protected Tetrasaccharide Core

“…Early attempts at the chemical grafting of the α- d -glucosyl residue on protected di-, tri-, and tetrasaccharide acceptors met issues, resulting in tedious purifications and poor yields of the α-linked glucosylated products. As a general trend in subsequent work, the glucosyl residue was introduced first to form a disaccharide building block featuring the branching point. ,,, While this strategy remains in use, S. flexneri target diversity and complexity call for improvements.…”

“…As a general trend in subsequent work, the glucosyl residue was introduced first to form a disaccharide building block featuring the branching point. 13,17,18,21 While this strategy remains in use, 22 S. flexneri target diversity and complexity call for improvements. However, although several stereoselective methods for the chemical synthesis of 1,2-cis glycosides were reported over the last decade, 23−29 there is still no general strategy enabling versatile 1,2-cis glucosylation, especially when considering complex acceptors.…”

Total synthesis of the O-antigen repeating unit of Providencia stuartii O49 serotype through linear and one-pot assemblies

“…Finally, the benzylidene and the benzyl groups were removed by hydrogenolysis using 10% Pd(OH) 2 /C in methanol at ambient temperature with a H 2 balloon, which afforded the target trisaccha- ride 1 in 68% yield over three steps (Scheme 6). The structure of 1 was confirmed by several NMR spectroscopic techniques such as 1 H NMR, DEPT-135, 13 C NMR, COSY, and HSQC as well as mass spectrometry using HRMS. The NMR data were found to correlate well with the data reported for the natural polysaccharide [38].…”

“…Due to their importance in regulating the host's immune system, the bacterial cell surface LPS in general and the O-antigens in particular have been proposed and reported as candidates for vaccine development [1][2][3][4][5][6][7][8]. This objective has been proposed to be achieved by the synthesis of chemically homogeneous glycoconjugates bearing the O-antigen oligosaccharide conjugated to peptides for eliciting the desired immune response through vaccines [9][10][11][12][13][14][15][16][17][18][19][20][21]. For the above purposes, large scale access to pure, defined, and homogeneous samples of the desired LPS oligosaccharides are essential for realization of the goal towards vaccine development against these pathogens .…”

Conjugation of Synthetic Trisaccharide of Staphylococcus aureus Type 8 Capsular Polysaccharide Elicits Antibodies Recognizing Intact Bacterium

“…The immunological mechanism remains unclear. During the course of our investigations on the synthesis of complex oligosaccharides, we have successfully completed several complicated bacterial lipopolysaccharide repeating antigens (Qin et al, 2018;Zou et al, 2018;Tian et al, 2020). Here, we describe the design and chemical synthesis of CP8 trisaccharide containing an amine linker at the reducing end with Dglucose and L-fucose as starting materials, which is ready for glycoconjugate preparation and glycan microarray fabrication.…”