# Synthesis of PSI Oligosaccharide for the Development of Total Synthetic Vaccine against Clostridium difficile

## TL;DR

This paper describes the first efficient synthesis of a key sugar structure from Clostridium difficile, which could help in developing a synthetic vaccine against the bacteria.

## Contribution

The study introduces a novel one-pot synthesis method for phosphorylated PSI oligosaccharides at gram scale.

## Key findings

- An efficient synthesis of phosphorylated PSI oligosaccharide and its derivatives was achieved.
- A one-pot strategy successfully produced a pentasaccharide repeating unit in gram quantities.
- The method allows for the synthesis of various lengths of PSI oligosaccharides.

## Abstract

Clostridium difficile causes
serious
nosocomial diarrhea in humans. In particular, C. difficile ribotype 027 strain, which is more virulent in nature, is associated
with higher mortality rates. To prevent disease caused by C. difficile, capsular polysaccharides such as PSI,
PSII, and PSIII from the outermost protective layer of C. difficile bacterium are good targets in the development
of vaccine against C. difficile. In
this study, we report for the first time an efficient synthesis of
phosphorylated PSI oligosaccharide and its derivatives in various
lengths. We have also developed a one-pot strategy for the synthesis
of a pentasaccharide repeating unit and used this approach to successfully
synthesize the protected pentasaccharides in the gram scale.