289653-64-1Relevant academic research and scientific papers
Synthesis of a derivative of a pentasaccharide repeating unit of the O-antigenic polysaccharide of the bacterium Klebsiella pneumoniae O3 as a benzoylated 2-methoxycarbonylethyl thioglycoside
Abronina,Galkin,Backinowsky,Grachev
scheme or table, p. 457 - 467 (2010/07/08)
Block synthesis of a fully benzoylated derivative of the pentasaccharide α-d-Manp-(1→3)-α-d-Manp-(1→2)-α-d-Manp-(1→2) -α-d-Manp-(1→2)-α-d-Manp-SCH2CH2CO 2Me, the glycoside of the repeating unit of the O-antigenic polysaccharide of the bacterium Klebsiella pneumoniae O3, was performed.
Synthesis of Thio-Linked Disaccharides by 1→2 Intramolecular Thioglycosyl Migration: Oxacarbenium versus Episulfonium Ion Intermediates
Johnston, Blair D.,Pinto, B. Mario
, p. 4607 - 4617 (2007/10/03)
The conversion of 1,1′-thio-linked glucopyranosyl α-D-mannopyranosides to 1,2-thio-linked methyl sophorosides or methyl kojibiosides is described. The method involves the 1→2-migration of the thioglucopyranosyl portion of the nonreducing disaccharide with inversion of configuration at C-2 of the mannopyranose ring and concomitant formation of the methyl glucopyranoside. The thioglucosyl migration does not occur when electron-withdrawing benzoate protecting groups are present. The rearrangement occurs with retention of configuration in the migrating thioglucoside but the methyl glycoside is formed as a mixture of α- and β-isomers. This is attributed to a mechanism involving an oxacarbenium-ion intermediate rather than an episulfonium-ion intermediate. The relevance of this work to recent theoretical predictions concerning the relative stability of such intermediates is discussed.
