Collect. Czech. Chem. Commun. 2004, 69, 1877-1888

Kinetics of Methylation of Methyl 5-Deoxy-α/β-D-xylofuranosides

Mária Oščendová and Jitka Moravcová*

Department of Chemistry of Natural Compounds, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic


The kinetics of methylation of methyl 5-deoxy-α-D-xylofuranoside (1), methyl 5-deoxy-β-D-xylofuranoside (2) and their partly methylated derivatives with methyl iodide in the presence of sodium hydroxide in acetonitrile was studied. The reaction rate was independent of the base concentration during the first half-time only and the methylation proceeded as a first-order reaction. The rate constants of all side and consecutive reactions were calculated and the influence of both polar and steric effect is discussed. The methylation of 1 was highly regioselective giving almost exclusively 5-deoxy-2-O-methyl-α-D-xylofuranoside.

Keywords: Regioselectivity; Rate constants; Partial methylation; Methyl pentofuranoside; Kinetics; Pentofuranosides; Glycosides; Carbohydrates; Methylated saccharides.

References: 20 live references.