Block Synthesis of Streptococcus pneumoniae Type 14 Capsular Polysaccharide Structures*

* In memory of Professor Jacques H. van Boom

Abstract

Synthesis of a thioglycoside tetrasaccharide block, β‐D‐Galp‐(1→4)‐β‐DGlcp‐(1→6)‐[β‐D‐Galp‐(1→4)]‐β‐D‐GlcNPhthp‐(1→SEt, corresponding to the repeating unit of Streptococcus pneumoniae serotype 14 CPS is described. Coupling of this block with a spacer followed by removal of an isopropylidene acetal yielded an acceptor, which was elongated with the donor block to give a protected dimer of the repeating unit. Iteration of this methodology yielded the trimer. Deprotection then produced an octa and a dodecasaccharide derivative ready for conjugation to proteins to afford immunoactive glycoconjugates.

* In memory of Professor Jacques H. van Boom

Keywords:

• Oligosaccharide synthesis
• Block synthesis
• Glycoconjugate vaccines

Acknowledgments

We are indebted to Professor Göran Karlsson at the Swedish NMR Centre for help with the interpretation of the NMR spectra of the octasaccharide 13. Financial support from the Swedish Research Council is gratefully acknowledged.

Notes

* In memory of Professor Jacques H. van Boom