6347-01-9Relevant articles and documents
A hydrothermally stable ytterbium metal-organic framework as a bifunctional solid-acid catalyst for glucose conversion
Burnett, David L.,Chamberlain, Thomas W.,Cherkasov, Nikolay,Clarkson, Guy J.,Degirmenci, Volkan,Krisnandi, Yuni K.,Oozeerally, Ryan,Pertiwi, Ralentri,Walton, Richard I.
, p. 11446 - 11449 (2019)
Yb6(BDC)7(OH)4(H2O)4 contains both bridging hydroxyls and metal-coordinated waters, possessing Br?nsted and Lewis acid sites. The material crystallises from water at 200 °C. Using the solid as a heterogenous catalyst, glucose is converted into 5-hydroxymethylfurfural, via fructose, with a total selectivity of ～70percent after 24 hours at 140 °C in water alone: the material is recyclable with no loss of crystallinity.
Substrate-dependent chemoselective aldose-aldose and aldose-ketose isomerizations of carbohydrates promoted by a combination of calcium ion and monoamines
Tanase, Tomoaki,Takei, Tomoyuki,Hidai, Masanobu,Yano, Shigenobu
, p. 303 - 312 (2007/10/03)
Epimerization of aldoses at C-2 has been extensively investigated by using various metal ions in conjunction with diamines, monoamines, and aminoalcohols. Aldoses are epimerized at C-2 by a combination of alkaline-earth or rare-earth metal ions (Ca2+, Sr2+, Pr3+, or Ce3+) and such monoamines as triethylamine. In particular, the Ca2+ -triethylamine system proved effective in promoting aldose-ketose isomerization as well as C-2 epimerization of aldoses. 13C NMR studies using D-(1-13C)glucose and D-(1-13C)galactose with the CaCl2 system in CD3OD revealed that the C-2 epimerization proceeds via stereospecific rearrangement of the carbon skeleton, or 1,2-carbon shift, and ketose formation proceeds partially through an intramolecular hydrogen migration or 1,2-hydride shift and, in part, via an enediol intermediate. These simultaneous aldose-aldose and aldose-ketose isomerizations showed interesting substrate-dependent chemoselectivity. Whereas the mannose-type aldoses having 2,3-erythro configuration (D-mannose, D-lyxose, and D-ribose) showed considerable resistance to both the C-2 epimerization and the aldose-ketose isomerization, the glucose-type sugars having 2,3-threo and 3,4-threo configurations, D-glucose and D-xylose, are mainly epimerized at C-2 and those having the 2,3-threo and 3,4-erythro configurations, D-galactose and D-arabinose, were mostly isomerized into 2-ketoses. These features are of potential interest in relevance to biomimic sugar transformations by metal ions.
Synthesis of glycosylamines: Identification and quantification of side products
Campa, Cristiana,Donati, Ivan,Vetere, Amedeo,Gamini, Amelia,Paoletti, Sergio
, p. 263 - 273 (2007/10/03)
The synthesis of some glycosylamines (1-amino-1-deoxy-D-glucose, 1-amino-1-deoxy- D-galactose and 1-amino-1-deoxylactose) was carried out by treatment of the corresponding reducing sugars with ammonium hydrogencarbonate in concentrated ammonia. The reaction mixture was first analyzed by capillary electrophoresis with indirect absorbance detection and high performance anion-exchange chromatography with pulsed amperometric detection. Beside glycosylcarbamate, a known reaction by-product, fructose and lactulose were detected during the synthesis of 1-amino-1-deoxyglucose and 1-amino-1-deoxylactose, respectively. Quantification of glycosylamines was carried out by micellar electrokinetic chromatography with UV detection of their 9-fluorenylmethyloxycarbonyl (Fmoc) derivatives; lactulosylamine was thus detected in the synthesis mixture of 1-amino-1-deoxylactose. The Fmoc-glycosylamines were easily purified from the other components of the crude synthesis mixtures.
Mechanism of the action of Leuconostoc mesenteroides B-512FMC dextransucrase: Kinetics of the transfer of D-glucose to maltose and the effects of enzyme and substrate concentrations
Kitaoka, Motomitsu,Robyt, John F.
, p. 183 - 191 (2007/10/03)
The kinetics of the reaction of Leuconostoc mesenteroides B-512FMC dextransucrase with sucrose were studied. This enzyme catalyzes the synthesis of dextran from sucrose with a k(cat) of 641 s-1 and the transfer of D-glucose from sucrose to maltose with a k(cat) of 1070 s-1. The enzyme was also found to catalyze two new reactions in the absence of sucrose, using dextran as the substrate; D-glucose was transferred from the non-reducing ends of dextran chains to maltose with a relatively low k(cat) of 3.2 s-1; and D-glucose was hydrolyzed from the non-reducing ends of dextran chains with a very low k(cat) of 0.085 s-1. Ping-pong/bi-bi kinetics of these reactions are consistent with the formation of a glucosyl-enzyme covalent intermediate. It is shown that an increase in the concentrations of both maltose and sucrose in the D-glucose transfer reaction to maltose gives an exponential decrease in the amount of dextran and a concomitant increase in the amount of acceptor products. It is further shown that increasing the amount of dextransucrase gives a decrease in the amount of dextran and an increase in the amount of acceptor products, after the sucrose has been consumed. This anomaly occurs because the relatively high amounts of enzyme catalyze the transfer of D-glucose from the non-reducing ends of the dextran chains to maltose, giving a decrease in the amount of dextran and an increase in the amount of acceptor product. Further, the high amounts of enzyme catalyze the hydrolysis of the D-glucose residues from the ends of the dextran chains, giving a decrease in the amount of dextran. These reactions are not observed when lower amounts of enzyme are used, as the reactions are much slower than the synthesis of dextran and the usual acceptor transfer reactions of D-glucose from sucrose to acceptor. Copyright (C) 1999 Elsevier Science Ltd.
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.
Catalytic Oxidation of Glucose on Bismuth-Promoted Palladium Catalysts
Besson, Michele,Lahmer, Faousy,Gallezot, Pierre,Fuertes, Patrick,Fleche, Guy
, p. 116 - 121 (2007/10/02)
Water solutions of glucose (1.66 mol liter-1) were oxidized with air at 313 K on palladium catalysts supported on active charcoal.High gluconate yields (99.3percent) were obtained in the presence of bismuth-promoted catalysis.Bismuth was deposited via a surface redox reaction on Pd/C catalysts containing 1- to 2-nm Pd particles.A STEM-EDX study showed that bismuth atoms are selectively and homogeneously deposited on the palladium particles.The catalyst can be recycled without loss of activity and selectivity.Bismuth was not leached from the catalyst during reaction and recycling.Bismuth adatoms prevent oxygen poisoning of the palladium surface by acting as a co-catalyst in the oxidative dehydrogenation mechanism.It was determined by calorimetric measurements that oxygen should adsorb preferentially on bismuth rather than on palladium.
C-2 Epimerization of Aldoses by Calcium Ion in Basic Solutions. A Simple System to Transform D-Glucose and D-Xylose into D-Mannose and D-Lyxose
Yanagihara, Ryoji,Soeda, Kaori,Shiina, Sumito,Osanai, Shuichi,Yoshikawa, Sadao
, p. 2268 - 2272 (2007/10/02)
Aldoses were epimerized at C-2 by Ca2+ in aqueous or alcoholic basic solutions through a stereospecific rearrangement of the carbon skeletons of the aldose.The skeletal rearrangement was confirmed by 13C NMR analysis of the reaction products.The reaction of - and -D-glucose afforded - and -D-mannose, respectively, as major products.The effects of metal ions, bases, and solvents were examined, and it was found that a high concentration of Ca2+ and a base (>pH 12.3) were especially effective for the present rearrangement.Separation of the reaction products was also effected by using Ca2+ cation-exchange chromatography.Thus, under the optimized conditions, D-mannose and D-lyxose, which are rare in nature and expensive, were easily obtained in high isolated yields from D-glucose and D-xylose, respectively.
Epimerization of Aldoses Catalysed by Self-organized Metallomicelles in an Aqueous Solution
Osanai, Shuichi,Yanagihara, Ryoji,Uematsu, Kimitake,Okumura, Atsuo,Yoshikawa, Sadao
, p. 1937 - 1940 (2007/10/02)
Nickel(II) complexes coordinated with long chain N-alkylated ethylenediamine ligands were synthesized.It was found that the complexes possessed a marked C-2 epimerization activity for aldoses in aqueous media.In contrast, a short chain diamine nickel(II) complex had little activity.The agreement between the formation of micelles and the enhancement of epimerization was clearly recognized.Amphiphilic complexes formed "metallomicelles" which coordinated the aldoses and produced a new ternary complex composed of nickel, diamine and sugar.The stereospecific epimerization occurred in this aggregate accompanied by carbon skeleton rearrangement.One explanation for the high epimerizing ability of the amphiphilic nickel complex is the accumulation effect of nickel ion and ethylenediamine at the micelle surface.
C-2 Epimerization of Aldoses Promoted by Combination of Monoamines and Alkaline Earth or Rare Earth Metal Ions, Involving a Rearrangement of the Carbon Skeleton
Tanase, Tomoaki,Murata, Takashi,Yano, Shigenobu,Hidai, Masanobu,Yoshikawa, Sadao
, p. 1409 - 1412 (2007/10/02)
Aldoses are rapidly epimerized at C-2 by combination of alkaline earth or rare earth metal ions (Ca2+, Sr2+,Pr3+, or Ce3+)and monoamines (triethlamine etc.). (13)C NMR studies using -D-glucose of the Ca2+ system revealed that this reaction proceeds via the stereospecific rearrangement of carbon skeleton.
