Synthesis of an unusual hexasaccharide repeating unit from the cell wall polysaccharide of Eubacterium saburreum strain T19

Abstract

Eubacterium saburreum is one of the human oral pathogens and has been proved to play a significant role in the development of periodontal diseases. The cell-surface polysaccharides expressed by this...

Recent progress in chemical synthesis of bacterial surface glycans

“…Other bacterial surface glycan oligosaccharides and analogs have been synthesized (Figure 2C) include those of group A Streptococcus (GAS) cell-wall glycans (50) [38]; Bacillus anthracis secondary cell wall glycan (51) [73] ** ; E. saburreum strain T19 cell wall glycan (52) [39]; S. natans cell wall glycan trisaccharide component (53) [76,77] ** ; B. multivorans EPS (54) [74]; lipoteichoic acid glycans from C. difficile (55) [40]; P. aeruginosa 1244 pilin (56) [75] ** ; K. pneumoniae biofilms (57) [41]; mycobacterial glycan (58) [42], arabinomannan oligosaccharides containing α1-6-linked Man, α1-2-linked Man, and/or α1-5-linked Ara ranging from hexasaccharide to dodecasaccharide (59) [44], and a 92-mer arabinogalactan 60 [43] ** .…”

“…Monosaccharide furanose forms are found in many microbial glycoconjugates, such as Galf in 32 and 58, Fucf in 52, Araf in 59 and 60. Compound 52 [39] contains two adjacent 1,2cis-fucofuranosides. The 1,2-cis-glycosyl linkage in its D-Fucf-α1-4Galhepp disaccharide building block (F3G_3) was formed stereoselectively in 92% yield with an α:β ratio of 7:1 using a D-Fucf donor (F3G_1) with the remote participation effect of its C3-O-benzoyl group.…”

“…The 1,2-cis-glycosyl linkage in its D-Fucf-α1-4Galhepp disaccharide building block (F3G_3) was formed stereoselectively in 92% yield with an α:β ratio of 7:1 using a D-Fucf donor (F3G_1) with the remote participation effect of its C3-O-benzoyl group. Introduction of the second α-D-Fucf was achieved using a 5-O-2-quinolinecarbonyl (Quin)-protected donor F3G_5 via the HAD strategy to obtain the trisaccharide building block F3G_6 for compound 52 [39]. Construction of the trisaccharide building block F3G_11 for compound 56 [42] was achieved by glycosylation of acceptor F3G_8 using a glycosyl fluoride donor F3G_7 to form disaccharide F3G_9 which reacted further with disaccharide F3G_10 to produce tetrasaccharide in an excellent 94% yield.…”