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Pyranose

About: Pyranose is a research topic. Over the lifetime, 1619 publications have been published within this topic receiving 35348 citations. The topic is also known as: pyranoses & hexopyranose.


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Journal ArticleDOI
TL;DR: In this article, a new synthetic method providing both enantiomers by heteroconjugate addition strategy was described for stereocontrolled synthesis of optically active compounds from sugar chirons.

17 citations

Journal ArticleDOI
TL;DR: 1H and 13C nuclear magnetic resonance studies show that 5KF exists in different forms in anhydrous dimethyl-d6 sulfoxide and D2O, and both the beta-pyranose and beta-furanose forms of 5Kf are proposed to be substrates for yeast hexokinase.
Abstract: 5-Keto-D-fructose (5KF) is isolated from cultures of Gluconobacter cerinus growing on D-fructose as the sole carbon source. 5KF is a substrate for hexokinase, fructokinase, and several polyol dehydrogenases. 1H and 13C nuclear magnetic resonance studies show that 5KF exists in different forms in anhydrous dimethyl-d6 sulfoxide and D2O. In dimethyl-d6 sulfoxide, 5KF exists as a spirane dimer with linked furanose and pyranose rings, similar to the structure reported for crystalline 5KF [Hassen, L., Hordvik, A., & Hove, R. (1976) J. Chem. Soc., Chem. Commun., 572-. In D2O, 5KF exists predominantly (greater than 95%) in a beta-pyranose form with the 5-keto group hydrated to form a gem-diol. 13C--1H coupling patterns, 13C relaxation measurements, and 13C deuterium-induced differential isotope shifts confirm this structure of 5KF. The phosphorylation of 5KF by fructokinase can be accounted for by an approximately 2% proportion of the beta-furanose form in solution at 25 degrees C. Both the beta-pyranose and beta-furanose forms of 5KF are proposed to be substrates for yeast hexokinase.

17 citations

Journal ArticleDOI
TL;DR: In this paper, two disaccharides, maltose and cellobiose, are used as model compounds to explore differences in thermal stability due to the orientation of the glycosidic bond.
Abstract: Thermochemical conversion of lignocellulosic biomass to renewable fuels and chemicals occurs through high temperature decomposition of the main structural components in plants, including cellulose, hemicellulose, and lignin. Cellulose and hemicellulose comprise mostly carbohydrates. Two disaccharides, maltose and cellobiose, are used as model compounds to explore differences in thermal stability due to the orientation of the glycosidic bond. First principles molecular dynamics and density functional theory have been used to probe the decomposition of these disaccharides during pyrolysis at 700 K. The results suggest that maltose, the α-disaccharide, is less thermally stable. Dynamic bond length analysis for maltose indicates that several CC bonds and the CO bonds on the pyranose ring demonstrate signs of weakening, whereas no such scissile bonds were identified for cellobiose. The higher stability of the cellobiose is believed to originate from the persistence of low-energy hydroxymethyl conformers throughout the simulation which enable strong inter-ring hydrogen bonding. Thermogravimetric and mass spectroscopic experiments corroborate the enhanced thermal stability of cellobiose, wherein the onset of decomposition was observed at higher temperatures for cellobiose than for maltose. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2562–2570, 2015

17 citations

Journal ArticleDOI
TL;DR: In this paper, Melezitose [O-α-d-glucopyranosyl-(1→3)-β-d -fructofuranosyl α- d -glucophyranoside] monohydrate was crystallized in two polymorphic forms (I and II) and the structure of form II, studied by X-ray crystallography, showed an orthorhombic cell having a 7.135 (4), b 15.362 (8), c 19.134 (8) A, space group P212121,

17 citations

Journal ArticleDOI
TL;DR: By this novel, two-step redox isomerization process the four disaccharide substrates could be converted to the corresponding keto-disaccharides allolactulose, gentiobiulose and isomaltulose in high yields, which could find application in food technology as alternative sweeteners.
Abstract: Pyranose 2-oxidase, a homotetrameric FAD-flavoprotein from the basidiomycete Trametes multicolor, catalyzes regioselectively the oxidation of the 1→6 disaccharides allolactose [β- d -Galp-(1→6)- d -Glc], gentiobiose [β- d -Glcp-(1→6)- d -Glc], melibiose [α- d -Galp-(1→6)- d -Glc], and isomaltose [α- d -Glcp-(1→6)- d -Glc] at position C-2 of their reducing moiety. The resulting glycosyl d -arabino-hexos-2-uloses can be reduced specifically at C-1 by NAD(P)H-dependent aldose reductase from the yeast Candida tenuis. By this novel, two-step redox isomerization process the four disaccharide substrates could be converted to the corresponding keto-disaccharides allolactulose [β- d -Galp-(1→6)- d -Fru], gentiobiulose [β- d -Glcp-(1→6)- d -Fru], melibiulose [α- d -Galp-(1→6)- d -Fru], and isomaltulose (palatinose, [α- d -Glcp-(1→6)- d -Fru]) in high yields. These products could find application in food technology as alternative sweeteners.

17 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202317
202228
202118
202027
201926
201819