Pyranoside‐into‐Furanoside Rearrangement of 4‐Pentenyl Glycosides in the Synthesis of a Tetrasaccharide‐Related to Galactan I of Klebsiella pneumoniae

Abstract

An efficient strategy for synthesis of a spacer‐armed tetrasaccharide related to galactan I of Klebsiella pneumoniae is described, which uses newly developed acid‐free conditions for the pyranoside‐into‐furanoside (PIF) rearrangement of a digalactoside bearing a 4‐pentenyl group at the anomeric position. The 4‐pentenyl aglycon was successfully used both as a leaving group in the glycosylation of 3‐(trifluoroacetamido)propanol, and as a temporary anomeric protecting group, allowing conversion into an imidate donor. Regioselective coupling of the disaccharide blocks gave the desired tetrasaccharide sequence required for investigation of the interaction of galactan I with immune‐system proteins.

Influence of per-O-sulfation upon the conformational behaviour of common furanosides

“…The knowledge of conformational changes occurring in sulfated furanosides may be important for better understanding of the driving force of the pyranoside- into -furanoside rearrangement [ 14 – 16 ], which is widely used for preparative synthesis of different oligosaccharides, including fragments of a galactomannan from Aspergillus fumigatus [ 17 – 19 ], diheteroglycan from Enterococcus faecalis [ 20 ], galactan I from Klebsiella pneumoniae [ 21 ] and fucoidan from brown seaweed Chordaria flagelliformis [ 22 ].…”

Lysozyme's lectin-like characteristics facilitates its immune defense function

“…The synthesis of tetrasaccharide 2 (Verkhnyatskaya et al . 2017) was based on similar approaches and is described in the online supplementary information (Scheme S1).…”

Convergent Synthesis of Oligosaccharides Structurally Related to Galactan I and Galactan II of Klebsiella Pneumoniae and their Use in Screening of Antibody Specificity

“…The preparation of Gal f ‐containing di‐, tetra‐ and hexasaccharides 4a – 6a described here includes first preparation of selectively substituted galactopyranoside block and its further pyranoside‐ into ‐furanoside (PIF) rearrangement into substituted galactofuranoside derivativate. Such approach was previously successfully applied by us to the synthesis of tetrasaccharide related to galactan I . The previously employed synthetic strategy included PIF rearrangement of the disaccharide precursor and regioselective glycosylation of the 2,3‐diol .…”

“…Such approach was previously successfully applied by us to the synthesis of tetrasaccharide related to galactan I . The previously employed synthetic strategy included PIF rearrangement of the disaccharide precursor and regioselective glycosylation of the 2,3‐diol . The synthetic scheme described below (see Scheme ) is more efficient for preparation of longer oligosaccharides and included PIF rearrangement of galactopyranoside precursor 14 followed by glycosylation of monohydroxyl acceptors.…”