Pal D, Naskar M, Bera A, Mukhopadhyay B. Chemical synthesis of the pentasaccharide repeating unit of the O-specific polysaccharide from Ruminococcus gnavus.
Carbohydr Res 2021;
507:108384. [PMID:
34229203 DOI:
10.1016/j.carres.2021.108384]
[Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 06/12/2021] [Accepted: 06/18/2021] [Indexed: 10/21/2022]
Abstract
Microorganisms present in the guts are the causative agents for various diseases in humans. More and more studies are correlating such diseases and the responsible microorganism. The Gram-positive bacterium Ruminococcus gnavus (R. gnavus) has been identified to be responsible for symptoms of Crohn's disease. R. gnavas produces a glucorhamnan polysaccharide and it is postulated that this polysaccharide induces inflammatory response through toll-like receptor 4 (TLR4). The current manuscript describes the chemical synthesis of the pentasaccharide repeating unit of the O-polysachharide from R. gnavus. The major challenge associated with this particular synthesis is the presence of two consecutive 1,2-cis glucose units. The target oligosaccharide is achieved through a linear strategy from commercially available sugars through rational protecting group manipulation. 1,2-cis glycosylation of glucose through remote participation of acyl group at the 6-O position is used successfully with excellent yield. In both cases, sole 1,2-cis products are obtained at -20 °C through the activation of thioglycosides.
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