Syntheses Of Tetrasaccharides And Its Analogues In Acinetobacter Baumannii SMAL Capsular By One-Pot Glycosylation

Acinetobacter baumannii is one of the three superbugs pathogens that pose the greatest threat to humans and need to be addressed urgently,announced by the World Health Organization in 2017.Antibiotic therapy and vaccine prevention and control are two effective measures to suppress bacterial pathogen infection.In view of the fact that conventional antibiotic antimicrobial treatment is prone to bacterial resistance,the development of related vaccines is particularly important.The composition and structure of bacterial surface polysaccharides are different from those of mammals,and these polysaccharides act as antigens to activate the body’s immune system and generate an immune response,which can lead to the development of sugar vaccines.Therefore,it is essential to obtain structurally determined bacterial surface polysaccharides.Chemical synthesis is an effective methods to solve the problem of obtaining polysaccharides on the surface of bacteria,among which One-Pot Glycosylation is one of the efficient synthesis strategies in sugar synthesis chemistry,which can reduce the post-treatment and purification steps of the reaction,thereby improving the synthesis efficiency.In this paper,a novel One-Pot Glycosylation synthesis strategy based on Au(I)and Cu(II)catalysts and temperature-guided by using Yu glycoside donor and he orthomethoxycarbonylethynylphenyl thioglycoside(MCEPT)glycoside donor.This strategy has the advantages of convenient operation,flexibility,and diversified products of the same donor and acceptor under different catalyst conditions.This strategy was used to complete the synthesis of surface capsular(CPS)tetrasaccharides and its analogues of Acinetobacter baumannii SMAL strain,and provide antigens for the development of related sugar vaccines.The One-Pot Glycosylation synthesis strategy developed in this paper can improve the synthesis efficiency of oligosaccharides and facilitate the acquisition of bacterial surface polysaccharides and their analogues with determined structure,thereby laying the foundation for the development of sugar vaccines.