Synthesis of the trisaccharide repeating unit of Stenotrophomonas maltophilia O6 antigen through step-wise and one-pot approaches

Synthetic conjugate vaccines are an important area of research for the prevention and occurrence of diseases caused by Gram-negative bacteria. For the development of such vaccines, access to the pure and homogeneous oligosaccharide fragments of the bacterial cell surface polysaccharides are necessary. Stenotrophomonas malto-philia is a typical opportunistic Gram-negative bacteria that causes severe pulmonary and other infections; often in hospitalized patients. With the emergence of multidrug resistant strains and increased virulence, new thera-peutic strategies are needed to combat the threat. Herein, we report the syntheses of the trisaccharide repeating unit of S. maltophilia O6 antigen through stepwise and one-pot assemblies of the trisaccharide. The target trisaccharide was appended with a 2-aminoethyl linker that could provide the opportunity for conjugation to carrier proteins for the synthesis of vaccine candidates.