Transformations of sugars in alkaline solutions

Isbell, Horace S.; Linek, K.; Hepner, K.E.

doi:10.1016/s0008-6215(00)86162-5

Cited by 24 publications

(18 citation statements)

References 12 publications

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“…Tritium, with a molecular weight three times that of the common natural isomer, might react more slowly than H. Goldstein (1966) observed a large kinetic isotope effect when the rate-limiting step in a reaction sequence involved the breaking of a covalent bond of the heavy atom. Isbell et al (1971) found an isotope effect for enolization of sugars in alkaline solutions. The ratio of the rate constants for loss of T and H (kr/ku) was 0.13.…”

Section: Resultsmentioning

confidence: 99%

Studies on limit-peptide pigments from glucose-casein browning systems using radioactive glucose

Clark¹,

Tannenbaum²

1973

J. Agric. Food Chem.

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Section: Resultsmentioning

confidence: 99%

Studies on limit-peptide pigments from glucose-casein browning systems using radioactive glucose

Clark¹,

Tannenbaum²

1973

J. Agric. Food Chem.

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“…[58] This triple-isomerization process was further named after its discoverers (hereinafter, LdB-AvE). [56] On the basis of detailed investigations of the LdB-AvE reaction, which included protium-deuterium and protium-tritium exchange measurements, [59b, [60][61][62] kinetic and UV-spectroscopic studies, [49] the plausible mechanism of the LdB-AvE reaction based on the "least motion" principle and involving enediolanion as a key-intermediate was proposed. [49,59] The LdB-AvE processes were long believed to be responsible for the isomerization of carbohydrates during the FR.…”

Section: Isomerization Of Monosaccharidesmentioning

confidence: 99%

Catalytic Formation of Monosaccharides: From the Formose Reaction towards Selective Synthesis

et al. 2014

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The formose reaction (FR) has been long the focus of intensive investigations as a simple method for synthesis of complex biologically important monosaccharides and other sugar-like molecules from the simplest organic substrate-formaldehyde. The fundamental importance of the FR is predominantly connected with the ascertainment of plausible scenarios of chemical evolution which could have occurred on the prebiotic Earth to produce the very first molecules of carbohydrates, amino- and nucleic acids, as well as other vitally important substances. The practical importance of studies on the FR is the elaboration of catalytic methods for the synthesis of rare and non-natural monosaccharides and polyols. This Minireview considers the FR from the point of view of chemists working in the field of catalysis with emphasis on the mechanisms of numerous parallel and consequent catalytic transformations that take place during the FR. Based on its kinetics, the FR may be considered as a non-radical chain process with degenerate branching. The Minireview also considers different approaches to the control of selectivity of carbohydrate synthesis from formaldehyde and lower monosaccharides.

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“…6,7) Many studies reported that glucose was isomerized to fructose more easily than mannose under alkaline conditions. 15,19,20) These studies were carried out at low reaction temperatures. The unique product distribution among the investigated saccharides in subcritical aqueous ethanol can be attributed to the difference in the temperature dependence of the rate constants of the reactions.…”

Section: Mutual Isomerization Of Hexosesmentioning

confidence: 99%

Kinetic analysis for the isomerization of glucose, fructose, and mannose in subcritical aqueous ethanol

Gao

Kobayashi

Adachi

2015

Bioscience, Biotechnology, and Biochemistry

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Fructose, glucose, and mannose were treated with subcritical aqueous ethanol for ethanol concentrations ranging from 0 to 80% (v/v) at 180–200 °C. The aldose–ketose isomerization was more favorable than ketose–aldose isomerization and glucose–mannose epimerization. The isomerization of the monosaccharides was promoted by the addition of ethanol. In particular, mannose was isomerized most easily to fructose in subcritical aqueous ethanol. The apparent equilibrium constants for the isomerizations of mannose to fructose, Keq,M→F, and glucose to fructose, Keq,G→F, were independent of ethanol concentration and increased with increasing temperature. Moreover, the Keq,M→F value was much larger than the Keq,G→F value. The enthalpies for the isomerization of mannose to fructose, ΔHM→F, and glucose to fructose, ΔHG→F, were estimated to be 18 and 24 kJ/mol, respectively, according to van’t Hoff equation. Subcritical aqueous ethanol can be used to produce fructose from glucose and mannose efficiently.

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Transformations of sugars in alkaline solutions

Cited by 24 publications

References 12 publications

Studies on limit-peptide pigments from glucose-casein browning systems using radioactive glucose

Studies on limit-peptide pigments from glucose-casein browning systems using radioactive glucose

Catalytic Formation of Monosaccharides: From the Formose Reaction towards Selective Synthesis

Kinetic analysis for the isomerization of glucose, fructose, and mannose in subcritical aqueous ethanol

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