INVESTIGADORES
SIGNORELLA Sandra Rosanna
artículos
Título:
Kinetics and mechanism of the chromic oxidation of 3-O-methyl-D-glucopyranose
Autor/es:
FRASCAROLI, M. I.; SALAS-PEREGRIN, J. M.; SALA, L. F.; SIGNORELLA, S.
Revista:
POLYHEDRON
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2009 vol. 28 p. 1049 - 1056
ISSN:
0277-5387
Resumen:
The oxidation of 3-O-methyl-D-glucopyranose (Glc3Me) by CrVI in acid medium yields CrIII, formic acid and 2-O-methyl-D-arabinose as final products when a 50-times or higher excess of Glc3Me over CrVI is used. The redox reaction takes place through the combination of CrVI ® CrIV ® CrII and CrVI ® CrIV ® CrIII pathways. Intermediacy of free radicals and CrII in the reaction was demonstrated by the observation of induced polymerization of acrylamide and detection of CrO22+ formed by reaction of CrII with O2. Intermediate oxo-CrV-Glc3Me species were detected by EPR spectroscopy. In 0.3 0.5 mol/L HClO4, intermediate CrV rapidly decompose to the reaction products, while, at pH 5.5 7.5 where the redox processes are very slow, five-coordinate CrV bis-chelates of the pyranose and furanose forms of Glc3Me remain more than 15 h in solution. The C1-C2 bond cleavage of Glc3Me upon reaction with CrVI distinguishes this derivative from glucose, which is oxidized to gluconic acid.
