Synthesis 2024; 56(06): 1007-1016
DOI: 10.1055/s-0042-1751460
paper
Emerging Trends in Glycoscience

Convergent Synthesis of the Octasaccharide Repeating Unit of the K55 Capsular Polysaccharide of Acinetobacter baumannii BAL_204 Strain

Samim Sahaji
,
Pradip Shit
,
Anup Kumar Misra
S.S. thanks UGC-MANF, India for financial support. This work was supported by SERB, New Delhi (Project No. CRG/2019/000352 dated 23.01.2020) (AKM).


Abstract

Synthesis of the octasaccharide repeating unit of the K55 capsular polysaccharide of Acinetobacter baumannii BAL_204 strain has been achieved in very good yield using a convergent [5+3] block glycosylation strategy. The pentasaccharide and trisaccharide components were synthesized using sequential stereoselective glycosylations. The p-methoxybenzyl (PMB) group was used as temporary alkyl protecting group, which was removed under the thiophilic glycosylation condition by raising the temperature. A late-stage TEMPO-mediated selective oxidation of primary hydroxyl group into carboxylic acid allowed getting the d-glucuronic acid moiety in the octasaccharide. A combination of N-iodosuccinimide (NIS) and perchloric acid supported over silica (HClO-SiO2) was used as a thiophilic promoter for the activation of thioglycosides. HClO4-SiO2 was also used as a solid acid activator for glycosyl trichloroacetimidate derivative.

Supporting Information



Publication History

Received: 28 March 2023

Accepted after revision: 03 May 2023

Article published online:
30 May 2023

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