title: Synthesis of regioselectively sulfated xylodextrins and crystal structure of sodium methyl beta-D-xylopyranoside 4-O-sulfate hemihydrate.
abstract: Methyl xylobioside and methyl xylotrioside were prepared from the peracetylated anomeric xylosyl trichloroacetimidates by reaction with methanol followed by Zemplén deacetylation. Methyl beta-D-xylopyranoside, methyl beta-D-xylobioside and methyl beta-D-xylotrioside were subjected to treatment with dibutyltin oxide followed by reaction with the trimethylamine/sulfur trioxide complex in tetrahydrofuran. This way, preferential sulfation of the terminal 4-hydroxy group at the nonreducing xylopyranosyl unit was achieved. In addition, partial sulfation at position 2 of the distal xylose unit was observed. The substitution pattern was derived from NMR spectroscopic data and was confirmed by the X-ray structure determination of sodium methyl beta-D-xylopyranoside 4-O-sulfate. The compound crystallized as a hemihydrate in a triclinic lattice of space group P1 and possesses a pseudomonoclinic 2D supramolecular structure. The sulfation of free pentose oligomers via their intermediate stannylene acetals may thus be exploited to generate biologically active oligosaccharides for biomedical applications.
authors.affiliation: Department of Chemistry, University of Natural Resources and Applied Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Abad-Romero
authors.forename: Kurt
authors.initials: K
authors.lastname: Mereiter
authors.forename: Herbert
authors.initials: H
authors.lastname: Sixta
authors.forename: Andreas
authors.initials: A
authors.lastname: Hofinger
authors.forename: Paul
authors.initials: P
authors.lastname: Kosma
mesh_terms: D018360:Crystallography, X-Ray; D006027:Glycosides / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009844:Oligosaccharides / Q000138:chemical synthesis / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry; D013237:Stereoisomerism; D013431:Sulfates / Q000737:chemistry*; D013463:Sulfuric Acid Esters / Q000737:chemistry*
chemical_list: D006027:Glycosides; D009844:Oligosaccharides; D011134:Polysaccharides; D013431:Sulfates; D013463:Sulfuric Acid Esters; C010807:xylosides; C007916:hemicellulose; C033522:methyl sulfate