title: Synthesis of methyl 2-acetamido-2,6-dideoxy-alpha- and beta-d-xylo-hexopyranosid-4-ulose, a keto sugar which misled the analytical chemists.
abstract: To understand the contradictory results on the structure of the lipopolysaccharide isolated from a Yersinia enterocolitica O:3, both anomers of methyl 2-acetamido-2,6-dideoxy-d-xylo-hexopyranosid-4-ulose were prepared. The key steps of the synthetic pathway were the selective acetylation of the methyl 2-acetamido-2,6-dideoxy-alpha,beta-d-glucopyranosides, the oxidation of the 4-position to form the keto-sugars, and deacetylation to provide the target compound. Surprisingly, the last step was accompanied by a disproportionation to give methyl 2-acetamido-2,6-dideoxy-alpha- and beta-d-glucopyranosides and N-(5-hydroxy-6-methyl-4-oxo-4H-pyran-3-yl)acetamide as side-products.
authors.affiliation: University of Rostock, Institute of Chemistry, Albert-Einstein-Strasse 3a, D-18059 Rostock, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Borowski
authors.forename: Dirk
authors.initials: D
authors.lastname: Michalik
authors.forename: Helmut
authors.initials: H
authors.lastname: Reinke
authors.forename: Christian
authors.initials: C
authors.lastname: Vogel
authors.forename: Anna
authors.initials: A
authors.lastname: Hanuszkiewicz
authors.forename: Katarzyna A
authors.initials: KA
authors.lastname: Duda
authors.forename: Otto
authors.initials: O
authors.lastname: Holst
mesh_terms: D000107:Acetylation; D007651:Keto Acids / Q000138:chemical synthesis* / Q000737:chemistry; D007661:Ketoses / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure
chemical_list: D007651:Keto Acids; D007661:Ketoses; C530759:methyl 2-acetamido-2,6-dideoxy-xylo-hexopyranosid-4-ulose