Synthesis of a teichoic acid fragment of <i>Bacillus subtilis</i> using a modified phosphotriester approach

Abstract

Abstract The synthesis of a teichoic acid fragment ( i.e. compound 8e ), containing three 3‐ O –(β‐glucopyranosyl)‐ sn ‐glycerol residues connected via two phosphodiester linkages, is described. The assemblage of the teichoic acid fragment was effected using a modified phosphotriester approach based on the use of 1‐hydroxybenzotriazole‐activated phosphorylating agents ( i.e. phosphorylating agents 5c and 6c ). Three suitably protected building blocks were prepared: i.e. , 2b , 3c and 4b . Special attention was paid to the preparation of the middle unit 3c which contains a stable phosphodiester anilidate to avoid intramolecular reaction of the free hydroxyl function on phosphorus. Compound 2b was condensed with derivative 3c to give fragment 7a . The aniline group could be removed from dimer 7a to give 7b , which was then condensed with monomer 4b to give the fully protected teichoic acid fragment 8a . Stepwise removal of the protecting group of 8a afforded the teichoic acid fragment 8e .