156967-55-4Relevant articles and documents
Oxidation of methyl and n-octyl α-D-glucopyranoside over graphite-supported platinum catalysts: Effect of the alkyl substituent on activity and selectivity
Vleeming, Johannes H.,Kuster, Ben F.M.,Marin, Guy B.
, p. 175 - 183 (1997)
The oxidation of methyl and n-octyl α-D-glucopyranoside to methyl and n-octyl α-D-glucopyranosiduronate with molecular oxygen over a graphite-supported platinum catalyst was investigated. An increase of the length of the n-alkyl substituent from methyl to n-octyl resulted in a ten-fold decrease of the catalyst activity and an increase of the selectivity at pH 8.0 and 323 K. The selectivity decreased with increasing pH. The lower activity for a longer n-alkyl substituent is attributed to steric effects upon adsorption on the platinum surface and not to internal diffusion limitations. A tentative reaction scheme is presented, which describes the formation of side products through oxidation of secondary hydroxyl groups, ring cleavage and hydrolysis. Major side products are mono- and di-carboxylates with 2, 4, and 6 carbon atoms and mono-carboxylates, resulting from the oxidation of the alkyl substituent. C-C-Bond cleavage mainly occurs between C-2 and C-3 or C-4 and C-5, the former being less important for a longer alkyl substituent. The higher selectivity for a longer alkyl substituent is attributed to its protecting ability against hydrolysis and the exposition of neighboring hydroxyl groups to the platinum surface.
Oxidation of different sugar residues catalyzed by [Ru(azpy)2(H2O)2]2+; A comparative study
Boelrijk, Alexandra E. M.,Dorst,Reedijk, Jan
, p. 536 - 541 (2007/10/03)
The oxidation of several sugars by NaBrO3 catalyzed by [Ru(azpy)2(H2O)2]2+, is reported and compared with earlier oxidation results with octyl α-D-glucoside (α-OGP). The sugars studied were 1-octyl β-D-glucoside (β-OGP), 1-octyl β-D-galactoside (β-OGaP), 1-phenyl β-D-glucoside (β-PGP), 1-methyl α-D-glucoside, 1-methyl β-D-glucoside and 1-decyl β-D-maltoside (β-DMP). The results with β-DMP are compared with previously reported oxidation results with β-DMP heterogeneously catalyzed over platinum. The structure of the sugar substrate appears to have a significant effect on the activity and selectivity of the oxidation reaction. The main conclusions from this study are that β-isomers are in general less reactive than α-isomers; α-PGP in particular is very unreactive. The kind of substitution (pnenyl versus alkyl, octyl versus methyl) on the anomeric centre has considerable effect on the reactivity of the sugar. The oxidation of β-DMP catalyzed by [Ru(azpy)2(H2O)2]2+ results in a number of different oxidation products. The C6-primary hydroxy groups of both glucose units of β-DMP can be oxidized to carboxylic groups, in contrast to the previously reported heterogeneous catalyzed oxidation of β-DMP by dioxygen. However, the main reaction is the splitting of the decyl chain from the maltose unit The α-1,4-O link between the glucose units appears to be quite stable under the catalytic oxidation conditions used. Based on the results obtained, possible reaction mechanisms are discussed.
Oxidation of octyl-α-D-glucopyranoside, catalysed by (2+) or (2+) (azpy = 2-(phenyl)azopyridine), produces octyl-α-D-glucuronic acid
Boelrijk, Alexandra E. M.,Reedijk, Jan
, p. 411 - 412 (2007/10/02)
Highly stable ruthenium-2-(phenyl)azopyridine catalysts effect an oxidation of octyl-α-D-glucopyranoside in aqueous conditions with NaBrO3 as a co-oxidant.The oxidation processes involve a two-electron transfer step.
