- Selective Reductive Dimerization of CO2into Glycolaldehyde
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The selective dimerization of CO2 into glycolaldehyde is achieved in a one-pot two-step process via formaldehyde as a key intermediate. The first step concerns the iron-catalyzed selective reduction of CO2 into formaldehyde via formation and controlled hydrolysis of a bis(boryl)acetal compound. The second step concerns the carbene-catalyzed C-C bond formation to afford glycolaldehyde. Both carbon atoms of glycolaldehyde arise from CO2 as proven by the labeling experiment with 13CO2. This hybrid organometallic/organic catalytic system employs mild conditions (1 atm of CO2, 25 to 80 °C in less than 3 h) and low catalytic loadings (1 and 2.5%, respectively). Glycolaldehyde is obtained in 53% overall yield. The appealing reactivity of glycolaldehyde is exemplified (i) in a dimerization process leading to C4 aldose compounds and (ii) in a tri-component Petasis-Borono-Mannich reaction generating C-N and C-C bonds in one process.
- Zhang, Dan,Jarava-Barrera, Carlos,Bontemps, Sébastien
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p. 4568 - 4575
(2021/05/04)
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- Catalytic Gels for a Prebiotically Relevant Asymmetric Aldol Reaction in Water: From Organocatalyst Design to Hydrogel Discovery and Back Again
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This paper reports an investigation into organocatalytic hydrogels as prebiotically relevant systems. Gels are interesting prebiotic reaction media, combining heterogeneous and homogeneous characteristics with a structurally organized active solid-like catalyst separated from the surrounding environment, yet in intimate contact with the solution phase and readily accessible via liquid-like diffusion. A simple self-assembling glutamine amide derivative 1 was initially found to catalyze a model aldol reaction between cyclohexanone and 4-nitrobenzaldehyde, but it did not maintain its gel structure during reaction. In this study, it was observed that compound 1 could react directly with the benzaldehyde to form a hydrogel in situ based on Schiff base 2 as a low-molecular-weight gelator (LMWG). This new dynamic gel is a rare example of a two-component self-assembled LMWG hydrogel and was fully characterized. It was demonstrated that glutamine amide 1 could select an optimal aldehyde component and preferentially assemble from mixtures. In the hunt for an organocatalyst, reductive conditions were applied to the Schiff base to yield secondary amine 3, which is also a highly effective hydrogelator at very low loadings with a high degree of nanoscale order. Most importantly, the hydrogel based on 3 catalyzed the prebiotically relevant aldol dimerization of glycolaldehyde to give threose and erythrose. In buffered conditions, this reaction gave excellent conversions, good diastereoselectivity, and some enantioselectivity. Catalysis using the hydrogel of 3 was much better than that using non-assembled 3 - demonstrating a clear benefit of self-assembly. The results suggest that hydrogels offer a potential strategy by which prebiotic reactions can be promoted using simple, prebiotically plausible LMWGs that can selectively self-organize from complex mixtures. Such processes may have been of prebiotic importance.
- Hawkins, Kirsten,Patterson, Anna K.,Clarke, Paul A.,Smith, David K.
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supporting information
p. 4379 - 4389
(2020/03/05)
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- Convergent in situ Generation of Both Transketolase Substrates via Transaminase and Aldolase Reactions for Sequential One-Pot, Three-Step Cascade Synthesis of Ketoses
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We describe an efficient three-enzyme, sequential one-pot cascade reaction where both transketolase substrates are generated in situ in a convergent fashion. The nucleophilic donor substrate hydroxypyruvate was obtained from l-serine and pyruvate by a transaminase-catalyzed reaction. In parallel, three different (2S)-α-hydroxylated aldehydes, l-glyceraldehyde, d-threose, and l-erythrose, were generated as electrophilic acceptors from simple achiral compounds glycolaldehyde and formaldehyde by d-fructose-6-phosphate aldolase catalysis. The compatibility of the three enzymes was studied in terms of temperature, enzyme ratio and substrate concentration. The efficiency of the process relied on the irreversibility of the transketolase reaction, driving a shift of the reversible transamination reaction and securing the complete conversion of all substrates. Three valuable (3S,4S)-ketoses, l-ribulose, d-tagatose, and l-psicose were obtained in good yields with high diastereoselectivity.
- Lorillière, Marion,Guérard-Hélaine, Christine,Gefflaut, Thierry,Fessner, Wolf-Dieter,Clapés, Pere,Charmantray, Franck,Hecquet, Laurence
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p. 812 - 817
(2019/12/27)
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- Shape-selective Valorization of Biomass-derived Glycolaldehyde using Tin-containing Zeolites
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A highly selective self-condensation of glycolaldehyde to different C4 molecules has been achieved using Lewis acidic stannosilicate catalysts in water at moderate temperatures (40–100 °C). The medium-sized zeolite pores (10-membered ring framework) in Sn-MFI facilitate the formation of tetrose sugars while hindering consecutive aldol reactions leading to hexose sugars. High yields of tetrose sugars (74 %) with minor amounts of vinyl glycolic acid (VGA), an α-hydroxyacid, are obtained using Sn-MFI with selectivities towards C4 products reaching 97 %. Tin catalysts having large pores or no pore structure (Sn-Beta, Sn-MCM-41, Sn-SBA-15, tin chloride) led to lower selectivities for C4 sugars due to formation of hexose sugars. In the case of Sn-Beta, VGA is the main product (30 %), illustrating differences in selectivity of the Sn sites in the different frameworks. Under optimized conditions, GA can undergo further conversion, leading to yields of up to 44 % of VGA using Sn-MFI in water. The use of Sn-MFI offers multiple possibilities for valorization of biomass-derived GA in water under mild conditions selectively producing C4 molecules.
- Tolborg, S?ren,Meier, Sebastian,Saravanamurugan, Shunmugavel,Fristrup, Peter,Taarning, Esben,Sádaba, Irantzu
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p. 3054 - 3061
(2016/11/17)
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- Catalytic effect of aluminium chloride on the example of the conversion of sugar model compounds
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Abstract In this work, the catalytic effect of the Bronsted acid hydrochloric acid, the Bronsted base sodium hydroxide and the Lewis acid AlCl3 on the conversion of biomass derived carbohydrates is investigated. On the example of the glycolaldehyde conversion, it is shown that the Lewis acid catalyses the ketol-endiol-tautomerism, the dehydration, the retro-aldol-reaction and the benzilic-acid-rearrangement. The main products are C4- and C6-carbohydrates as well as their secondary products 2-hydroxybut-3-enoic acid 1 and several furans. Under the same reaction conditions hydrochloric acid catalyzes mainly the dehydration and sodium hydroxide the tautomerism and subsequent aldolization.
- Schwiderski, Martin,Kruse, Andrea
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- Zeolite-catalyzed isomerization of tetroses in aqueous medium
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The isomerization of erythrose (ERO) was studied in water over commercially available large-pore zeolites, e.g. H-Y, H-USY and H-beta. Among the employed zeolites, H-USY(6) was found to efficiently isomerize the sugar, yielding 45% erythrulose (ERU), 42% ERO and 3% of the epimer threose (THO) (corresponding to the equilibrium mixture), i.e. total tetrose yield 90%, after reaction for 5-7 h at 120 °C. Changing the solvent from water to methanol decreased the yield of ERU markedly to 18% and gave only a total yield of tetroses of 27% which is significantly lower than that obtained in water. Hence, the results demonstrate that water is the preferred solvent compared to lower alcohols for zeolite-catalyzed tetrose isomerization, which is opposite to what has been found previously for analogous pentose and hexose isomerization. A reuse study revealed further that H-USY(6) could be applied for at least five reaction runs with essentially unchanged activity and without significant aluminum leaching from the catalyst. The use of benign reaction conditions and an industrially pertinent solid catalyst in combination with water establishes a new, green tetrose isomerization protocol. the Partner Organisations 2014.
- Saravanamurugan, Shunmugavel,Riisager, Anders
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p. 3186 - 3190
(2014/08/18)
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- Efficient biocatalytic processes for highly valuable terminally phosphorylated C5 to C9 D-ketoses
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A green enzymatic strategy for the synthesis of terminally phosphorylated C5 to C9 naturally occurring D-ketose phosphates and analogues was developed using D-fructose-6-phosphate aldolase (FSA) as a catalyst. This enzyme has stereoselectively catalysed aldol reactions between glycolaldehyde phosphate or ribose-5-phosphate as an acceptor substrate and dihydroxyacetone, hydroxyacetone or hydroxybutanone as a donor. Furthermore, D-glycero-d-altro-2-octulose 8-phosphate was obtained using a straightforward one-pot domino biocatalytic system involving FSA, ribulose-5-phosphate epimerase and ribose-5-phosphate isomerase controlling five contiguous asymmetric centres and starting from achiral material.
- Guerard-Helaine,Debacker,Clapes,Szekrenyi,Helaine,Lemaire
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supporting information
p. 1109 - 1113
(2014/03/21)
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- Asymmetric organocatalytic formation of protected and unprotected tetroses under potentially prebiotic conditions
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Esters of proteinogenic amino acids efficiently catalyse the formation of erythrose and threose under potentially prebiotic conditions in the highest yields and enantioselectivities yet reported. Remarkably while esters of (l)-proline yield (l)-tetroses, esters of (l)-leucine, (l)-alanine and (l)-valine generate (d)-tetroses, offering the potential to account for the link between natural (l)-amino acids and natural (d)-sugars. The effect of pH and NaCl on the yields and enantioselectivities was also investigated and was shown to be significant, with the optimal enantioselectivities occurring at pH 7.
- Burroughs, Laurence,Clarke, Paul A.,Forintos, Henrietta,Gilks, James A. R.,Hayes, Christopher J.,Vale, Matthew E.,Wade, William,Zbytniewski, Myriam
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experimental part
p. 1565 - 1570
(2012/04/05)
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- Efficient immobilization of fructose-6-phosphate aldolase in layered double hydroxide: Improved stereoselective synthesis of sugar analogues
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Fructose-6-phosphate aldolase immobilized on layered double hydroxide (FSA@LDH) has been characterized and evaluated as a biocatalyst in aldol reactions. The versatile FSA@LDH showed a comparable activity to the free FSA and can be reused several times without a notable loss of activity.
- Guerard-Helaine, Christine,Legeret, Bertrand,Fernandes, Carlos,Prevot, Vanessa,Forano, Claude,Lemaire, Marielle
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supporting information; experimental part
p. 776 - 779
(2011/06/22)
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- A mutant D-fructose-6-phosphate aldolase (Ala129Ser) with improved affinity towards dihydroxyacetone for the synthesis of polyhydroxylated compounds
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A mutant of D-fructose-6-phosphate aldo-lase (FSA) of Escherichia coli, FSA A129S, with im-proved catalytic efficiency towards dihydroxyacetone (DHA), the donor substrate in aldol addition reac-tions, was explored for synthetic applications. The Kcat/KM value for DHA was 17-fold higher with FSA A129S than that with FSA wild type (FSA wt). On the other hand, for hydroxyacetone as donor sub-strate FSA A129S was found to be 3.5-fold less effi-cient than FSA wt. Furthermore, FSA A129S also ac-cepted glycolaldehyde (GA) as donor substrate with 3.3-fold lower affinity than FSA wt. This differential selectivity of both FSA wt and FSA A129S for GA makes them complementary biocatalysts allowing a control over donor and acceptor roles, which is par-ticularly useful in carboligation multi-step cascade synthesis of polyhydroxylated complex compounds. Production of the mutant protein was also improved for its convenient use in synthesis. Several carbohy-drates and nitrocyclitols were efficiently prepared, demonstrating the versatile potential of FSA A129S as biocatalyst in organic synthesis.
- Castillo, Jose A.,Guerard-Helaine, Christine,Gutierrez, Mariana,Garrabou, Xavier,Sancelme, Martine,Schuermann, Melanie,Inoue, Tomoyuki,Helaine, Virgil,Charmantray, Franck,Gefflaut, Thierry,Hecquet, Laurence,Joglar, Jesus,Clapes, Pere,Sprenger, Georg A.,Lemaire, Marielle
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scheme or table
p. 1039 - 1046
(2010/07/14)
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- Efficient asymmetric organocatalytic formation of erythrose and threose under aqueous conditions
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Esters of proteinogenic amino acids efficiently catalyse the formation of erythrose and threose under aqueous conditions in the highest yields and enantioselectivities yet reported. Remarkably while esters of (l)-proline yield (l)-carbohydrates, esters of (l)-leucine and (l)-alanine generate (d)-carbohydrates, offering the potential to account for the prebiotic link between natural (l)-amino acids and natural (d)-sugars.
- Burroughs, Laurence,Vale, Matthew E.,Gilks, James A. R.,Forintos, Henrietta,Hayes, Christopher J.,Clarke, Paul A.
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supporting information; experimental part
p. 4776 - 4778
(2010/09/05)
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- Methods for the electrolytic production of erythrose or erythritol
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Methods for the production of erythrose and/or erythritol are provided herein. Preferably, the methods include the step of electrolytic decarboxylation of a ribonic acid or arabinonic acid reactant to produce erythrose. Optionally, the reactant can be obtained from a suitable hexose sugar, such as allose, altrose, glucose, fructose or mannose. The erythrose product can be hydrogenated to produce erythritol.
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Page/Page column 8-9
(2008/06/13)
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- Mitochondrially targeted antioxidants
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The invention provides mitochondrially targeted antioxidant compounds comprising a lipophilic cation moiety covalently coupled to a glutathione peroxidase mimetic. These compounds can be used to treat patients who would benefit from the reduction of oxidative stress.
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- Prebiotic carbohydrate synthesis: Zinc-proline catalyzes direct aqueous aldol reactions of α-hydroxy aldehydes and ketones
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Zn-proline catalyzed aldolisation of glycoladehyde gave mainly tetroses whereas in the cross-aldolisation of glycoladehyde and rac-glyceraldehyde, pentoses accounted for 60% of the sugars formed with 20% of ribose. The Royal Society of Chemistry 2005.
- Kofoed, Jacob,Reymond, Jean-Louis,Darbre, Tamis
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p. 1850 - 1855
(2007/10/03)
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- Methods for treating plants and enhancing plant growth using polyacylglycosides and/or polyalkylglycosides and formulations for same
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Methods and formulations for treating plants and enhancing plant growth and for safening high concentrations of one or more phytocatalysts, wherein one or more formulations, comprising, a high concentration of one or more phytocatalysts, and an effective amount of one or more polyacylglycosides and polyalkylglycosides; and isomers, and metabolites, salts, hydrates, esters, amines, and derivatives of the polyacylglycosides and polyalkylglycosides, and combinations thereof, is applied to the plants.
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- Kinetics and mechanism of electron transfer reactions of aquo- thallium(III) perchlorate with aldopentoses
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The kinetics of electron transfer reactions of aquo-thallium(III) perchlorate with D-xylose, D-arabinose and D-ribose have been studied under the pseudo-first order condition. The fractional order with respect to aldopentose concentrations suggest the Michaelis-Menten type of kinetics. The rate decreases with acid concentration, and is strongly inhibited by the complexing chloride, acetate ions and acetic acid. A free radical mechanism involving aldopentose derived free radical has proposed for these reactions. Rate law consistent with the experimental data has been also derived.
- Fadnis, Anand G.,Arzare, Sapana
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p. 235 - 237
(2007/10/03)
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- Metal-mediated decarbonylation and dehydration of ketose sugars
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Ketose sugars can be decarbonylated and/or dehydrated by the action of certain metal complexes. Fructose reacts with 1 equiv of RhCl(PPh3)3 (1) in N-methyl-2-pyrrolidinone (NMP) at 130°C to give furfuryl alcohol, Rh(CO)Cl(PPh3)2 (2), and a small amount of 1-deoxyerythritol. 1,3-Dihydroxyacetone consumes 2 equiv of 1, giving methane and ca. 2 mol of 2. With manno-2-heptulose the primary product is 2,7-anhydromanno-2-heptulopyranose. The mechanisms of these unusual reactions have been studied by using 13C-labeling experiments and model reactions employing Pd(II) and HCl. Attempts to make the reactions catalytic using [Rh(Ph2PCH2CH2CH2PPh 2)2]+[BF4]- in place of 1 were not successful. The use of NMP as a solvent offers some advantages in the acid-catalyzed synthesis of certain carbohydrate dehydration products, as exemplified by the conversion of manno-2-heptulose to its 2,7-anhydride and of 2-deoxyglucose to 1-(2-furanyl)-1,2-ethanediol.
- Andrews, Mark A.
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p. 2703 - 2708
(2008/10/08)
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- FURANOSE RING ANOMERIZATION: A KINETIC STUDY OF THE 5-DEOXYPENTOSES AND 5-O-METHYLPENTOSES
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The anomerzation of 5-deoxy-L-pentoses (1-4) and 5-O-methyl-D-pentoses (5-8) in aqueous solution has been studied by (13)C saturation-transfer n.m.r. (s.t.-n.m.r.) spectroscopy, using compounds substituted with (13)C at the anomeric carbon atom.Unidirectional rate-constants of ring-opening (kopen) and ring closing (kclose) have been obtained for these compounds under identical solution conditions (50mM acetate buffer, pH 4.0 at 60 deg C), and have been compared to those measured for the D-tetroses (9 and 10) and four D-pentose 5-phosphates (11-14).Based on these comparisons, several correlations between furanose structure and reactivity have been revealed, and models have been proposed to explain the observed kinetic behavior of compounds 1-10.The effect of exocyclic structure on acid-catalyzed rate-constants was also examined by comparing the behavior of 5-deoxy-L-lyxose and 5-O-methyl-D-lyxose.Some consideration has been given to identifying the factors (enthalpic and entropic) that may play roles in determining the effect of structure on anomerization reactivity.
- Snyder, Joseph R.,Serianni, Anthony S.
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- KINETICS OF OXIDATION OF MONOSACCHARIDES WITH CERIUM(IV)
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The kinetics of the oxidation of D-galactose, D-glucose, D-mannose, D-fructose, L-sorbose, L-arabinose, D-ribose, and D-xylose with cerium(IV) in perchloric acid were studied.Two complexes were found to form in each case.The first complex forms in a pre-equilibrium reaction during mixing in the stopped-flow apparatus.Michaelis-Menten kinetics were observed for this oxidation.The values of the complex-formation and dissociation rate-constants were determined in 1.0 M HClO4.The dissociation partly involves the oxidation of the first complex and partly, the formation of a second, more-stable complex.This second complex is oxidized much more slowly than the first, and the values of the pseudo-first-order rate-constant were again determined in 1.0 M HClO4.The values proved to be almost constant in the range of 0.1 M to 1.0 M , from which it was concluded that practically all of the Ce(IV) was complexed.
- Virtanen, Pentti O. I.,Lindroos, Raija,Oikarinen, Eija,Vaskuri, Juhani
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- Anomerization of Furanose Sugars and Sugar Phosphates
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Thermodynamic and kinetic parameters for the ring-opening and -closing reactions of several aldo- and ketofuanoses and their phosphate esters have been determined by NMR line-width and saturation-transfer methods.Cyclic forms interconvert via a single, acyclic carbonyl form under either acid or base catalysis.Ring-opening rates do not correlate with thermodynamic stability of the rings.For aldofuranose phosphates, α anomers open faster than β anomers; for ketofuranose phosphates the converse is observed.Intramolecular catalysis of anomerization by the phosphate group of sugar phosphates is documented.Biological and mechanistic implications of the observed kinetics are discussed.
- Pierce, John,Serianni, Anthony S.,Barker, Robert
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p. 2448 - 2456
(2007/10/02)
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- Kinetics, Catalysis, and Mechanism of the Secondary Reaction in the Final Phase of the Formose Reaction
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In the final phase of the formose reaction sugars are formed by the reaction of glycolaldehyde, glyceraldehyde and dihydroxyacetone.The application of high-pressure liquid chromatography allows for the first time to investigate intermediate and final products quantitatively.The results of kinetical investigations allow to suggest a reaction mechanism for the secondary reaction in the final phase of the formose reaction.This mechanism is compared with that of the starting phase and other known mechanisms.From the results metal ion-catalyzed aldol reactions have to be assumed.
- Harsch, Guenther,Bauer, Hermann,Voelter, Wolfgang
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p. 623 - 635
(2007/10/02)
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- THE FORMOIN REACTION
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The formoin reaction, i.e., the autocondensation of formaldehyde in an aprotic solvent catalysed by the conjugate base of a thiazolium ion, has been studied in detail.Glucose, galactose, dihyroxyacetone dimer, xylose, and arabinose have been identified as products.The influence of catalysts, temperature, basicity, and reaction time is documented.N,N-Dimethylformamide is a more convenient solvent than ether, benzene, or diglyme.Ethyldi-isopropylamine affords better yields of carbohydrate material than triethylamine.At =60 deg, aldol condensations are reduced to a minimum.After 1-2 h of reaction (depending on the conditions), the yields begin to decrease and become zero after ca. 24 h.
- Castells, Josep,Lopez-Calahorra, Francisco,Geijo, Fernando
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p. 197 - 208
(2007/10/02)
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- Anomerization of Furanose Sugars: Kinetics of Ring-Opening Reactions by 1H and 13C Saturation-Transfer NMR Spectroscopy
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With the tetroses D-threose and D-erythrose, kinetic and thermodynamic parameters for the interconversion of α- and β-furanoses and the acyclic hydrate with the intermediate aldehyde form have been obtained from 1H and 13C NMR measurements.Unidirectional rate constants for the various equilibria involving the aldehyde have been determined, and from them the overall rate constants for interconversion of the abundant species.The approach can be applied to systems in which only solutions at tautomeric equilibrium are available or in which interconversions are too rapid to observe by other methods.Analyses by 13C NMR were facilitated by the use of tetroses.Aqueous solutions of the tetroses were examined at 17-81 deg C by 13C and 1H NMR spectroscopy to evaluate tautomeric composition.Solutions of D-threose contain ca. 51percent α-furanose and ca. 38percent β-furanose at all temperatures, while the amount of aldehyde (a) increases from 0.7 to 4.7percent and the amount of hydrate (h) decreases from 10.2 to 7.1percent. ΔG (kcal mol-1), ΔH (kcal mol-1), and ΔS (cal mol-1 K-1) at 25 deg C were estimated for the reaction a -> α, -2.4, -6.0, and -12; a -> β, -2.2, -6.0, -13; a -> h, -1.4, -7.3, -20, respectively.Rate constants for ring opening of the tetroses in 2H2O were obtained by 1H and 13C saturation-transfer NMR spectroscopy by saturating H-1 or C-1 of the aldehyde, respectively, and observing the transfer of saturation to the α- and β-furanose and hydrate resonances.Rate constants (+/-10percent) for the ring-opening reactions of D-threose (unbuffered) are as follows: α-furanose, 0.034 s-1 (51 deg C), 0.10 s-1 (66 deg C); β-furanose, 0.083 s-1 (38 deg C), 0.53 s-1 (66 deg C).Ring-closing rate constants (+/-18percent), determined from equilibrium constants, and ring-opening rate constants are as follows: α-furanose, 0.74 s-1 (51 deg C), 1.5 s-1 (66 deg C); β-furanose, 2.0 s-1 (38 deg C), 5.9 s-1 (66 deg C).Activation energies were estimated for β-threofuranose ring-opening (14 +/- 3 kcal mol-1) and ring-closing (8 +/- 2 kcal mol-1) reactions.From the unidirectional rate constants, overall rate constants at 66 deg C for the conversion of α- and β-threofuranose were calculated as follows: kαβ = 0.08 +/- 0.01 s-1, kβα = 0.11 +/- 0.01 s-1.Rate constants for ring-opening of D-threose and D-erythrose in 50 mM sodium acetate (p2H 5.0) were compared.At 55 deg C, α-erythrose (0.40 s-1) > β-threose (0.36 s-1) > β-erythrose (0.19 s-1) > α-threose (0.11 s-1).Rate constants obtained by 13C and 1H ST NMR spectroscopy were in good agreement.
- Serianni, Anthony S.,Pierce, John,Huang, Shaw-Guang,Barker, Robert
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p. 4037 - 4044
(2007/10/02)
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