79434-10-9Relevant academic research and scientific papers
Rare keto-aldoses from enzymatic oxidation: Substrates and oxidation products of pyranose 2-oxidase
Freimund, Stefan,Huwig, Alexander,Giffhorn, Friedrich,Koepper, Sabine
, p. 2442 - 2455 (2007/10/03)
Pyranose oxidases are known to oxidise D-glucose, D-xylose and L- sorbose to keto-aldoses, biochemically interesting compounds that may also be used for synthetic purposes in a variety of reactions. In this study pyranose oxidase from the basidiomycete Peniophora gigantea was investigated, and it was found that this enzyme is able to oxidise a broad variety of substrates very effectively. In analogy to its natural mode of action, most substrates are oxidised regioselectively in position 2. Certain compounds, however, are converted into 3-keto derivatives, and the enzyme even exhibits transfer potential, that is, disscharides are formed from β-glycosides of higher alcohols. Substrates that may be oxidised at C-2 in yields between 40-98% are D-allose, D-galactose, 6-deoxy-D-glucose, D-gentiobiose, α-D-glucopyranosyl fluoride and the very interesting 3-deoxy-D-glucose. 1,5-Anhydro-D-glucitol (1-deoxy-D-glucose) is very effectively oxidised in position 2 in 98% yield and additionally gives a product of dioxidation at C-2 and C-3 upon prolonged reaction time Selective oxidation at C-3 was found for 2-deoxy-D-glucose in very good yields and for methyl β-D-gluco- and methyl β-galactopyranoside in lower yields. All oxidation products were unequivocally characterised by NMR spectroscopy and/or chemical derivatisation. In addition, the kinetic data of the enzymatic reactions were determined for all substrates. On the basis of these data and the structural characteristics of the substrates, a model for the minimal structural requirements of the enzyme-substrate interaction is suggested. The enzyme presumably uses two different binding modes for the regioselective C-2 and the C-3 oxidations, which are described.
DEGRADATION OF 2-DEOXYALDOSES BY ALKALINE HYDROGEN PEROXIDE
Isbell, Horace S.,Frush, Harriet L.,Naves, Renee,Soontracharoen, Preeda
, p. 111 - 122 (2007/10/02)
Reaction of 2-deoxy-D-arabino-hexose, 2-deoxy-D-lyxo-hexose, and 2-deoxy-D-erythro-pentose with alkaline hydrogen peroxide in the presence of magnesium hydroxide afforded the corresponding 2-deoxyaldonic acid, the 1,4-lactone, and the 1-O-formyl derivative of the next lower alditol.The 2-deoxyaldonic acids were separeted in 60-80 percent yields, as new, crystalline lithium salts.The 1,4-lactones were obtained under conditions that precluded intermediate formation of the free acids; preasumbly, the reaction proceeded by way of an intermediate, furanosyl hydroperoxide, which was converted into the lactone by elimination of water.With an excess of alkaline hydrogen peroxide, in the absence of magnesium hydroxide, the substrates were degraded to formic acid, with concurrent decomposition of hydrogen peroxide.It is shown that decomposition of hydrogen peroxide is catalyzed by hydroperoxide anion, and that is takes place by both a chain, and a non-chain, process.The decomposition reactions afford an abundant source of hydroxyl radical capable of oxidizing a wide variety of compounds.
