Bromine oxidation of methyl alpha- and beta-pyranosides of D-galactose, D-glucose, and D-mannose.
Methyl alpha- and beta-pyranosides of D-galactose, D-glucose, and D-mannose have been oxidized with bromine in aqueous solution at various pH values. The resulting keto glycosides were converted into their more-stable O-methyloxime derivatives which were characterized by spectroscopy and chromatography. Oxidation at a ring carbon atom where the hydrogen is axial is hindered by bulky substituents in syn (i.e., a 1,3) diaxial relationship. Thus, the aglycon group in the alpha anomers protects position 3, the axial HO-4 in galactopyranosides protects position 2, and the axial HO-2 in mannopyranosides protects position 4 from oxidation.
D001966:Bromine; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008722:Methods; D008756:Methylgalactosides; D008757:Methylglucosides; D008759:Methylglycosides; D008766:Methylmannosides; D010084:Oxidation-Reduction
D008756:Methylgalactosides; D008757:Methylglucosides; D008759:Methylglycosides; D008766:Methylmannosides; D001966:Bromine