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Hydrogenation of fructose on Ru/C catalysts
The hydrogenation of D-fructose on Ru/C catalysts was studied. Under the conditions applied (1 bar H2, 72 °C), the furanose forms of D-fructose react, while the pyranose forms do not. However, all anomers adsorb with comparable strength on the surface. The reaction rate is controlled by product inhibition. The selectivity to D-mannitol can be increased from 47 to 63% by promotion of Pd/C and Pt/C catalysts with Sn. (C) 2000 Elsevier Science Ltd.
Heinen, Annemieke W,Peters, Joop A,Van Bekkum, Herman
p. 449 - 457
(2000)
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Selective and Scalable Synthesis of Sugar Alcohols by Homogeneous Asymmetric Hydrogenation of Unprotected Ketoses
Sugar alcohols are of great importance for the food industry and are promising building blocks for bio-based polymers. Industrially, they are produced by heterogeneous hydrogenation of sugars with H2, usually with none to low stereoselectivities. Now, we present a homogeneous system based on commercially available components, which not only increases the overall yield, but also allows a wide range of unprotected ketoses to be diastereoselectively hydrogenated. Furthermore, the system is reliable on a multi-gram scale allowing sugar alcohols to be isolated in large quantities at high atom economy.
Tindall, Daniel J.,Mader, Steffen,Kindler, Alois,Rominger, Frank,Hashmi, A. Stephen K.,Schaub, Thomas
supporting information
p. 721 - 725
(2020/10/19)

HYDROGENATION OF L-SORBOSE
The invention relates to a process for L-Iditol by hydrogenating L-Sorbose. Further, the invention also relates to a use of a transition metal complex as hydrogenation catalyst for L-Sorbose. The invention relates to a process for the preparation of L-Iditol comprising at least one reaction step, in which a composition comprising L-Sorbose and hydrogen is reacted in the presence of a transition metal catalyst complex in a homogeneous solution, wherein the transition metal catalyst complex comprises at least one chiral ligand containing at least one phosphorus atom, which is capable of coordinating to the transition metal, and wherein the transition metal is selected from metals of groups 8, 9 and 10 of the periodic table of the elements according to IUPAC. The invention further relates to a use of a transition metal complex as defined above and below as hydrogenation catalyst for compositions comprising L-Iditol or mixtures thereof.
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(2021/10/22)

Direct conversion of cellulose into isosorbide over Ni doped NbOPO4catalysts in water
Isosorbide is a versatile chemical intermediate for the production of a variety of drugs, chemicals, and polymers, and its efficient production from natural cellulose is of great significance. In this study, bifunctional catalysts based on niobium phosphates were prepared by a facile hydrothermal method and used for the direct conversion of cellulose to isosorbide under aqueous conditions. NH3-TPD analysis showed that a high acid content existed on the catalyst surface, and pyridine infrared spectroscopic analysis confirmed the presence of both Lewis acid and Br?nsted acid sites, both of which played an important role in the process of carbohydrate conversion. XRD and H2-TPR characterization determined the composition and the hydrogenation centers of the catalyst. An isosorbide yield of 47% could be obtained at 200 °C for 24 h under 3 MPa H2 pressure. The Ni/NbOPO4 bifunctional catalyst retains most of its activity after five consecutive runs with slightly decreased isosorbide yield of 44%. In addition, a possible reaction mechanism was proposed that the synergistic effect of surface acid sites and hydrogenation sites was favorable to enhancing the cascade dehydration and hydrogenation reactions during the conversion of cellulose to isosorbide. This study provides as an efficient strategy for the development of novel multifunctional heterogeneous catalysts for the one-pot valorisation of cellulose. This journal is
Guo, Jiaxing,He, Minyao,Li, Cuiqing,Liu, ShanShan,Song, Yongji,Wang, Hong,Wang, Xincheng
supporting information
p. 10292 - 10299
(2020/07/14)

Highly efficient catalytic conversion of cellulose into acetol over Ni-Sn supported on nanosilica and the mechanism study
Selective conversion of cellulose into high value-added C3 chemicals is a great challenge in biorefinery due to the complicated reaction process. In this work, 61.6% yield of acetol was obtained by one pot conversion of cellulose using Ni-Sn/SiO2 catalysts. A series of characterization methods including TEM, STEM-HAADF, EDS, AAS, XRD, XPS, H2-TPR, Py-FTIR, and CO2-TPD were carried out to explore the structure-activity relationship. The strong basicity of the catalysts was a key factor affecting the production of acetol. In addition, catalysts with the hydrothermally stable L-acid sites and no B-acid sites inhibited side reactions and ensured efficient conversion of cellulose into small molecules. Further studies showed that the formation of the Ni3Sn4 alloy significantly promoted the acetol production, and its weak hydrogenation activity inhibited further conversion of acetol. Noninteger valence tin species (Snδ+ and SnOx) were formed both in Ni3Sn4 and Sn/SiO2. These Sn species were the source of basic sites and the active sites for catalyzing cellulose to acetol. Under the synergistic catalysis of Sn/SiO2 and the Ni3Sn4 alloy, cellulose was efficiently converted into acetol. This work provides guidance for the selective conversion of cellulose into C3 products.
Liu, Xiaohao,Liu, Xiaodong,Xu, Guangyue,Zhang, Ying,Wang, Chenguang,Lu, Qiang,Ma, Longlong
p. 5647 - 5656
(2019/11/05)

Effect of carbon chain length on catalytic C–O bond cleavage of polyols over Rh-ReOx/ZrO2 in aqueous phase
Production of linear deoxygenated C4 (butanetriols, -diols, and butanols), C5 (pentanetetraols, -triols, -diols, and pentanols), and C6 products (hexanepentaols, -tetraols, -triols, -diols, and hexanols) is achievable by hydrogenolysis of erythritol, xylitol, and sorbitol over supported-bimetallic Rh-ReOx (Re/Rh molar ratio 0.5) catalyst, respectively. After validation of the analytical methodology, the effect of some reaction parameters was studied. In addition to C–O bond cleavage by hydrogenolysis, these polyols can undergo parallel reactions such as epimerization, cyclic dehydration, and C–C bond cleavage. The time courses of each family of linear deoxygenated C4, C5, and C6 products confirmed that the sequence of appearance of the different categories of deoxygenated products followed a multiple sequential deoxygenation pathway. The highest selectivity to a mixture of linear deoxygenated C4, C5, and C6 products at 80percent conversion was favoured under high pressure in the presence of 3.7wt.percentRh-3.5wt.percentReOx/ZrO2 catalysts (54–71percent under 80 bar) at 200 °C.
Besson, Michèle,Da Silva Perez, Denilson,Perret, Noémie,Pinel, Catherine,Sadier, Achraf
(2019/08/30)

Role of the Strong Lewis Base Sites on Glucose Hydrogenolysis
This work reports the individual role of strong Lewis base sites on catalytic conversion of glucose hydrogenolysis to acetol/lactic acid, including glucose isomerisation to fructose and pyruvaldehyde rearrangement/hydrogenation to acetol/lactic acid. Las
Yazdani, Parviz,Wang, Bo,Gao, Feng,Kawi, Sibudjing,Borgna, Armando
p. 3845 - 3853
(2018/07/31)

Hydrothermally Stable Ruthenium–Zirconium–Tungsten Catalyst for Cellulose Hydrogenolysis to Polyols
In this work, we describe a catalytic material based on a zirconium–tungsten oxide with ruthenium for the hydrogenolysis of microcrystalline cellulose under hydrothermal conditions. With these catalysts, polyols can be produced with high yields. High and stable polyol yields were also achieved in recycling tests. A catalyst with 4.5 wt % ruthenium in total achieved a carbon efficiency of almost 100 %. The prepared Zr-W oxide is mesoporous and largely stable under hydrothermal conditions (493 K and 65 bar hydrogen). Decomposition into the components ZrO2 and WO3 could be observed at temperatures of 1050 K in air.
Lucas, Martin,Fabi?ovicová, Katarina,Claus, Peter
p. 612 - 618
(2017/12/28)

METHOD FOR PRODUCING ISOPROPANOL BY CATALYTIC CONVERSION OF CELLULOSE
This invention provides a method for producing isopropanol from cellulose, which is characterized by: cellulose is catalytically converted to isopropanol under existence of a Cu-Cr catalyst. In the method, the Cu-Cr catalyst contains an active phase of CuCr2O4 or further contains an active phase selected from a group consisting of CuO and Cr2O3; the mass ratio of cellulose and water is 15 wt% or below; and the temperature of catalytic reaction is 200-270℃.
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(2017/07/13)

Influence of the Surface Chemistry of Multiwalled Carbon Nanotubes on the Selective Conversion of Cellulose into Sorbitol
Carbon nanotubes (CNT) were submitted to liquid-phase chemical treatments using HNO3 and subsequently to gas-phase thermal treatments to incorporate different sets of oxygenated groups on the surface. The modified CNT were used as supports for 0.4 wt % Ru in the direct conversion of ball-milled cellulose to sorbitol and high conversions were reached after 3 h at 205 °C. Ru supported on the original CNT, although less active, was the most selective catalyst for the one-pot process (70 % sorbitol selectivity after 2 h). Unlike the one-pot process, the support acidity greatly promoted the rate of cellulose hydrolysis (35 % increase after 2 h) and the glucose selectivity (12 % increase after 2 h). The rate of glucose hydrogenation was almost not affected by the support modification. However, the catalyst acidity improved the sorbitol selectivity from glucose. The support acidity was a central factor for the one-pot conversion of cellulose, as well as for the individual hydrolysis and hydrogenation steps, and the original CNT supported Ru catalyst was the most efficient and selective catalyst for the direct conversion of cellulose to sorbitol.
Ribeiro, Lucília S.,Delgado, Juan J.,de Melo órf?o, José J.,Ribeiro Pereira, M. Fernando
p. 888 - 896
(2017/03/13)

One-pot catalytic conversion of cellulose into polyols with Pt/CNTs catalysts
A series of Pt nanoparticles supported on carbon nanotubes (CNTs) were synthesized using the incipient-wetness impregnation method. These catalysts were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscope (TEM) techniques. The characterization results indicate that the Pt nanoparticles were highly dispersed on the surface of the CNTs, and the mean size was less than 5 nm. These catalysts were utilized to convert cellulose to hexitol, ethylene glycerol (EG), and 1,2-propylene glycol (1,2-PG) under low H2 pressure. The total yields were as high as 71.4% for EG and 1,2-PG using 1 Pt/CNTs as the catalyst in the hydrolytic hydrogenation of cellulose under mild reaction conditions.
Yang, Li,Yan, Xiaopei,Wang, Qiwu,Wang, Qiong,Xia, Haian
supporting information
p. 87 - 92
(2015/03/05)

Aqueous phase hydrogenolysis of glucose to 1,2-propanediol over copper catalysts supported by sulfated spherical carbon
Aqueous phase hydrogenolysis of glucose was carried out over copper catalysts supported by sulfated spherical carbon for selective production of 1,2-propanediol. The sulfated carbon shows higher acidity by sulfation of its resin precursor than unsulfated or commercial ones. By changing copper loading, the hydrogenolysis capability and the acidity of catalysts were modified to suitable extents, which can optimize the selectivity to 1,2-propanediol. At a moderate copper loading, 5.0Cu/s-AC catalyst has the highest yield of 1,2-propanediol. This catalyst has a lifetime of over 300 h. However, its stability is required to be further improved.
Liang, Dong,Liu, Chengwei,Deng, Shuping,Zhu, Yulei,Lv, Chunxiang
p. 108 - 113
(2014/07/08)

Promoting effect of SnOx on selective conversion of cellulose to polyols over bimetallic Pt-SnOx/Al2O3 catalysts
Cellulose is the most abundant source of biomass in nature, and its selective conversion into polyols provides a viable route towards the sustainable synthesis of fuels and chemicals. Here, we report the marked change in the distribution of polyols in the cellulose reaction with the Sn/Pt atomic ratios in a wide range of 0.1-3.8 on the SnOx-modified Pt/Al 2O3 catalysts. Such a change was found to be closely related to the effects of the Sn/Pt ratios on the activity for the hydrogenation of glucose and other C6 sugar intermediates involved in the cellulose reaction as well as to the notable activity of the segregated SnO x species for the selective degradation of the sugar intermediates on the Pt-SnOx/Al2O3 catalysts. At lower Sn/Pt ratios of 0.1-1.0, there existed electron transfer from the SnOx species to the Pt sites and strong interaction between the catalysts, as characterized by temperature-programmed reduction in H2 and infrared spectroscopy for CO adsorption, which led to their superior hydrogenation activity (per exposed Pt atom), and in-parallel higher selectivity to hexitols (e.g. sorbitol) in the cellulose reaction, as compared to Pt/Al 2O3. The hexitol selectivity reached the greatest value of 82.7% at the Sn/Pt ratio of 0.5, nearly two times that of Pt/Al 2O3 at similar cellulose conversions (～20%). As the Sn/Pt ratios exceeded 1.5, the Pt-SnOx/Al2O3 catalysts exhibited inferior hydrogenation activity (per exposed Pt atom), due to the formation of the crystalline Pt-Sn alloy, which led to the preferential conversion of cellulose to C2 and especially C3 products (e.g. acetol) over hexitols, most likely involving the isomerization of glucose to fructose and retro-aldol condensation of these sugars on the segregated SnOx species, apparently in the form of Sn(OH)2. These findings clearly demonstrate the feasibility for rational control of the cellulose conversion into the target polyols (e.g. acetol or propylene glycol), for example, by the design of efficient catalysts based on the catalytic functions of the SnOx species with tunable hydrogenation activity.
Deng, Tianyin,Liu, Haichao
p. 116 - 124
(2013/02/26)

Sorbitol dehydrogenase of Aspergillus niger, SdhA, is part of the oxido-reductive d-galactose pathway and essential for d-sorbitol catabolism
In filamentous fungi d-galactose can be catabolised through the oxido-reductive and/or the Leloir pathway. In the oxido-reductive pathway d-galactose is converted to d-fructose in a series of steps where the last step is the oxidation of d-sorbitol by an NAD-dependent dehydrogenase. We identified a sorbitol dehydrogenase gene, sdhA (JGI53356), in Aspergillus niger encoding a medium chain dehydrogenase which is involved in d-galactose and d-sorbitol catabolism. The gene is upregulated in the presence of d-galactose, galactitol and d-sorbitol. An sdhA deletion strain showed reduced growth on galactitol and growth on d-sorbitol was completely abolished. The purified enzyme converted d-sorbitol to d-fructose with Km of 50 ± 5 mM and v max of 80 ± 10 U/mg.
Koivistoinen, Outi M.,Richard, Peter,Penttilae, Merja,Ruohonen, Laura,Mojzita, Dominik
experimental part
p. 378 - 383
(2012/07/14)

Copper-based catalysts for efficient valorization of cellulose
Noble causes: Cellulose is effectively converted into methanol, propylene, and ethylene glycol over Cu-based catalysts. Overall yields of above 93 %, together with 63 % yield of C1-C3 compounds, can be reached over simple noble-metal
Tajvidi, Kameh,Pupovac, Kristina,Kuekrek, Murhat,Palkovits, Regina
p. 2139 - 2142
(2013/01/15)

Selective conversion of microcrystalline cellulose into hexitols on nickel particles encapsulated within ZSM-5 zeolite
A highly active and selective Ni/ZSM-5 catalyst was prepared by a simple method. A selectivity of 91.2% to hexitols was obtained at intermediate conversion in the hydrolytic hydrogenation of cellulose.
Liang, Guanfeng,Cheng, Haiyang,Li, Wei,He, Limin,Yu, Yancun,Zhao, Fengyu
supporting information; experimental part
p. 2146 - 2149
(2012/09/10)

METHOD FOR PRODUCING ETHYLENE GLYCOL FROM POLYHYDROXY COMPOUND
A method for producing ethylene glycol, including (a) adding a polyhydroxy compound and water to a sealed high-pressure reactor, (b) removing air and introducing hydrogen, and (c) allowing the polyhydroxy compound to react in the presence of a catalyst while stiffing. The catalyst includes a first active ingredient and a second active ingredient. The first active ingredient includes a transition metal of Group 8, 9, or 10 selected from iron, cobalt, nickel, ruthenium, rhodium, palladium, iridium, and platinum, and/or a mixture thereof. The second active ingredient includes a metallic state of molybdenum and/or tungsten, or a carbide, nitride, or phosphide thereof. The method is carried out at a hydrogen pressure of 1-12 MPa, at a temperature of 120-300° C. for not less than 5 min in a one-step catalytic reaction. The efficiency, selectivity, and the yield of ethylene glycol are high. The preparation process is simple and the materials used are renewable.
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(2011/04/14)

Heteropoly acids as efficient acid catalysts in the one-step conversion of cellulose to sugar alcohols
Cellulose and even spruce can be converted efficiently into valuable platform chemicals via combined hydrolysis and hydrogenation in the aqueous phase. Thereby, heteropoly acids together with supported ruthenium catalysts show not only high activity but also remarkable selectivity to sugar alcohols reaching up to 81% yield of C4 to C6 sugar alcohols in only 7 h at 160 °C.
Palkovits, Regina,Tajvidi, Kameh,Ruppert, Agnieszka M.,Procelewska, Joanna
supporting information; experimental part
p. 576 - 578
(2011/03/17)

Amino acid catalyzed neogenesis of carbohydrates: A plausible ancient transformation
Hexose sugars play a fundamental role in vital biochemical processes and their biosynthesis is achieved through enzyme-catalyzed pathways. Herein we disclose the ability of amino acids to catalyze the asymmetric neogenesis of carbohydrates by sequential cross-aldol reactions. The amino acids mediate the asymmetric de novo synthesis of natural L- and D-hexoses and their analogues with excellent stereoselectivity in organic solvents. In some cases, the four new stereocenters are assembled with almost absolute stereocontrol. The unique feature of these results is that, when an amino acid is employed as the catalyst, a single reaction sequence can convert a protected glycol aldehyde into a hexose in one step. For example, proline and its derivatives catalyze the asymmetric neogenesis of allose with > 99% ee in one chemical manipulation. Furthermore, all amino acids tested catalyzed the asymmetric formation of natural sugars under prebiotic conditions, with alanine being the smallest catalyst. The inherent simplicity of this catalytic process suggests that a catalytic prebiotic "gluconeogenesis" may occur, in which amino acids transfer their stereochemical information to sugars. In addition, the amino acid catalyzed stereoselective sequential cross-aldol reactions were performed as a two-step procedure with different aldehydes as acceptors and nucleophiles. The employment of two different amino acids as catalysts for the iterative direct aldol reactions enabled the asymmetric synthesis of deoxysugars with > 99% ee. In addition, the direct amino acid catalyzed C2+C 2+C2 methodology is a new entry for the short, highly enantioselective de novo synthesis of carbohydrate derivatives, isotope-labeled sugars, and polyketide natural products. The one-pot asymmetric de novo syntheses of deoxy and polyketide carbohydrates involved a novel dynamic kinetic asymmetric transformation (DYKAT) mediated by an amino acid.
Cordova, Armando,Ibrahem, Ismail,Casas, Jesus,Sunden, Henrik,Engqvist, Magnus,Reyes, Efraim
p. 4772 - 4784
(2007/10/03)

METHOD OF DESALTING SUGAR SOLUTION AND ANION EXCHANGER
The present invention provides the means for suppressing the production of decomposition reactant, isomerization reactant, colored material, and so on when a saccharide solution is desalted, thereby suppressing the production of impurities and preventing coloration of an ion exchange resin and decrease in the desalting capacity of the ion exchange resin. The desalting of a saccharide solution is performed by using an anion exchange resin supporting a carbonate ion and/or a hydrogencarbonate ion.
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(2008/06/13)

METHOD FOR PRODUCING SUGAR ALCOHOL
A process for producing sugar alcohols having six carbon atoms, which comprises hydrogenating ketohexose, such as psicose, tagatose, sorbose and the like, in the presence of a catalyst containing a metal selected from the elements belonging to the eighth family in the periodic table, such as nickel, ruthenium, platinum, palladium and the like, is provided. According to this process, sugar alcohols having six carbon atoms can be produced efficiently at a large amount, the separation and recovering of the catalyst after completing the reaction are facilitated, and sugar alcohols having a desired production ratio can be produced efficiently.
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(2008/06/13)

Multiple Forms of Xylose Reductase in Candida intermedia: Comparison of Their Functional Properties Using Quantitative Structure-Activity Relationships, Steady-State Kinetic Analysis, and pH Studies
The xylose-fermenting yeast Candida intermedia produces two isoforms of xylose reductase: one is NADPH-dependent (monospecific xylose reductase; msXR), and another is shown here to prefer NADH ≈4-fold over NADPH (dual specific xylose reductase; dsXR). To compare the functional properties of the isozymes, a steady-state kinetic analysis for the reaction D-xylose + NAD(P)H + H + ? xylitol + NAD(P)+ was carried out and specificity constants (kcat/Kaldehyde) were measured for the reduction of a series of aldehydes differing in side-chain size as well as hydrogen-bonding capabilities with the substrate binding pocket of the enzyme. dsXR binds NAD(P)+ (KiNAD+ = 70 μM; KiNADP+ = 55 μM) weakly and NADH (Ki = 8 μM) about as tightly as NADPH (Ki = 14 μM). msXR shows uniform binding of NADPH and NADP + (KiNADP+ ≈ KiNADPH = 20 μM). A quantitative structure-activity relationship analysis was carried out by correlating logarithmic kcat/Kaldehyde values for dsXR with corresponding logarithmic kcat/Kaldehyde values for msXR. This correlation is linear with a slope of ≈1 (r2 = 0.912), indicating that no isozyme-related pattern of substrate specificity prevails and aldehyde-binding modes are identical in both XR forms. Binary complexes of dsXR-NADH and msXR-NADPH show the same macroscopic pK of ≈9.0-9.5, above which the activity is lost in both enzymes. A lower pK of 7.4 is seen for dsXR-NADPH. Specificity for NADH and greater binding affinity for NAD(P)H than NAD(P)+ are thus the main features of enzymic function that distinguish dsXR from msXR.
Nidetzky, Bernd,Brueggler, Kaspar,Kratzer, Regina,Mayr, Peter
p. 7930 - 7935
(2007/10/03)

A Definitive Synthesis of D-myo-Inositol 1,4,5,6-Tetrakisphosphate and Its Enantiomer D-myo-Inositol 3,4,5,6-Tetrakisphosphate from a Novel Butane-2,3-diacetal-Protected Inositol
New and rapid syntheses of the enantiomeric intracellular signalling molecules D-myo-inositol 1,4,5,6-tetrakisphosphate (1a) and D-myo-inositol 3,4,5,6-tetrakisphosphate (1b) are described. The synthetic strategy employs the novel butane-2,3-diacetal-prot
Mills, Stephen J.,Riley, Andrew M.,Liu, Changsheng,Mahon, Mary F.,Potter, Barry V. L.
p. 6207 - 6214
(2007/10/03)

Impact of the central hydroxyl groups on the activity of symmetrical HIV-1 protease inhibitors derived from L-mannaric acid
The influence of the central hydroxyl groups on the anti-viral activity of symmetrical HIV-1 protease inhibitors derived from L-mannaric acid has been examined. L-Iditol was synthesized and used as a chiral precursor for the synthesis of the corresponding inhibitor with inverted configuration at C-3 and C-4. Key intermediates were 3,4-O-isopropylidene-L-iditol and the activated L-idaric acid succinimidyI ester. The configurations of the central hydroxyl groups required for optimal inhibition of the HIV-1 protease were determined to be the C-3R and C-4R, i.e. the L-manno-configuration. Three C2-symmetric inhibitors were converted to their thiocarbonates and reduced to provide the corresponding hydroxyethyl transition-state mimics. Deletion of the C-4 hydroxyl group in these inhibitors gave no further improvement in the anti-viral activity. (C) 2000 Published by Elsevier Science Ltd.
Wachtmeister, Johanna,Mühlman, Anna,Classon, Bj?rn,Kvarnstr?m, Ingemar,Hallberg, Anders,Samuelsson, Bertil
p. 3219 - 3225
(2007/10/03)

The oxidation of fructose on Pt/C catalysts. The formation of D-threo- hexo-2,5-diulose and the effect of additives
This paper describes a study on the oxidation of D-fructose with molecular oxygen on Pt/C catalysts. Two major products are formed: 2-keto-D- gluconic acid and D-threo-hexo-2,5-diulose ('5-ketofructose'). Deactivation of the catalyst was observed, caused both by over-oxidation of the active surface and inhibition of the reaction by 2-ketogluconic acid. Although promotion of the catalyst with bismuth did not prevent deactivation, it improved the selectivity to 2-ketogluconic acid, probably due to coordination of fructose to the promoter. Other promoting metals (tin, lead and antimony) and additives like borate and hexamethylenetetramine were less successful.
Heinen, Annemieke W.,Peters, Joop A.,Van Bekkum, Herman
p. 155 - 164
(2007/10/03)

Thermodynamics of reactions catalyzed by l-iditol 2-dehydrogenase: The xylose assimilation pathway
Apparent equilibrium constants and calorimetric enthalpies of reaction have been measured for the following enzyme catalyzed (L-iditol 2-dehydrogenase) biochemical reactions in phosphate buffer at pHs near 7.5 and at the temperature 298.15 K D-sorbitol(aq) + NADox(aq) = D-fructose(aq) + NADred(aq), L-iditol(aq) + NADox(aq) = L-sorbose(aq) + NADred(aq), xylitol(aq) + NADox(aq) = D-xylulose(aq) + NADred(aq). Here, NADox is β-nicotinamide-adenine dinucleotide (oxidized form) and NADred is β-nicotinamide-adenine dinucleotide (reduced form). The results are used to calculate equilibrium constants and standard molar enthalpies, entropies, and Gibbs free energies for reference reactions involving specific species. Standard formation properties and standard transformed formation properties of the biochemical reactants are also calculated. The thermodynamics of the xylose assimilation pathway is summarized.
Tewari, Yadu B.,Goldberg, Robert N.
p. 1127 - 1144
(2007/10/03)

Total synthesis of the L-hexoses
Enantiomerically pure polyhydroxylated natural products are synthesized by using a reiterative two-carbon extension cycle consisting of four key transformations. The generality and efficiency of this methodology are demonstrated in the total synthesis of all eight L-hexoses.
Ko, Soo Y.,Lee, Albert W. M.,Masamune, Satoru,Reed III, Lawrence A.,Sharpless, K. Barry,Walker, Frederick J.
p. 245 - 264
(2007/10/02)

Polyamides and polyesters containing 2,4:3,5-di-O-methylene-L-idaroyl residues
Electrochemical oxidation of 2,4:3,5-di-O-methylene-D-gluconic acid in strong alkaline medium afforded a mixture of 2,4:3,5-di-O-methylene-D-glucaric acid 4 and 2,4:3,5-di-O-methylene-L-idaric acid 1 in a 1/8 ratio with a current efficiency of 53percent.Force-field calculations using Allinger's molecular mechanics program MM2p85 on 1 and 4 indicate that these cis-fused tetrahydro-dioxino-1,3-dioxin ring systems possess an O-inside conformation with a steric energy of 110.3 and 123.5 kJ*mol-1, respectively.Their conformation was confirmed by 400-MHz 1H- and 100-MHz 13C NMR measurements.A series of polycondensates were prepared by homogeneous solution polymerisation of 1 with an aromatic diol or aromatic diamine, which were analyzed by DSC and TGA.
Tinnemans, A. H. A.,Budding, H. A.,Stein, F.,Venekamp, J. C.
p. 181 - 186
(2007/10/02)

Interglucosyl Attack of Hydroxyl Group to Epoxy Ring of 2A,3A-Anhydro-(2AS)-α-cyclodextrin. Selective Preparation of 3A,2B-Anhydro-α-cyclodextrin
2A,3A-Anhydro-(2AS)-α-cyclodextrin was isomerized exclusively to 3A,2B-anhydro-α-cyclodextrin by the reaction with aqueous alkali.This implies the selective and interglucosyl attack of 3F-OH to the epoxy ring.
Fujita, Kahee,Tahara, Tsutomu,Sasaki, Hideaki,Egashira, Yoshimitsu,Shingu, Tetsuro,et al.
p. 917 - 920
(2007/10/02)

Chiral Ligands for Organometallic Catalysis containing Two Dioxolane Rings
Treatment of D-mannitol 1,6-dibenzoate with a catalytic quantity of toluene-p-sulphonic acid in 2,2-dimethoxypropane leads to the formation of two cyclic acetals, 4R,8R,9R,10R-2,2',6,6'-tetramethyl-4,8-bis(benzoyloxymethyl)-1,3,5,7-tetraoxadecalin and R,R'-4,4'-bi-(2,2-dimethyl-5-benzoyloxymethyldioxolanyl) in comparable amounts.Successive reaction with sodium methoxide in methanol, methanesulphonyl chloride, and lithium or potassium diphenylphosphide gave the corresponding phosphines namely 4S,8S,9S,10S-2,2',6,6'-tetramethyl-4,8-di-1,3,5,7-tetraoxadecalin and S,S-4,4'-bi-.Similarly, starting from L-iditol, the diphosphines 4R,8S,9S,10R-2,2',6,6'-tetramethyl-4,8-di-1,3,5,7-tetraoxadecalin and S,R-4,4'-bi- were obtained.It was demonstrated through (31)P n.m.r. studies that both cis- and trans-chelate complexes of rhodium were formed by these biphosphine ligands.Their potential in asymmetric hydrogenation was demonstrated, for low to moderate yields of amino acids were formed from a variety of enamide precursors.
Brown, John M.,Dayrit, Fabian M.,Sinou, Denis
p. 91 - 96
(2007/10/02)

Synthesis of Optically Active Inositol Derivatives Starting from D-Glucurono-6,3-lactone
D-Glucurono-6,3-lactone was converted to optically active and partially protected inositols.The synthetic strategy involves an efficient conversion of the D-gluco configuration to the L-ido configuration and dials to cyclitols.
Watanabe, Yutaka,Mitani, Motohiro,Ozaki, Shoichiro
p. 123 - 126
(2007/10/02)

1H Nuclear Magnetic Resonance Spectra and Conformations of Alditols in Deuterium Oxide
The 1H n.m.r. spectra of the tetritols, pentitols, and hexitols in deuterium oxide have been recorded at 400 MHz, and the shifts and coupling constants obtained by computer simulation of the spectra.The shifts and 3J coupling constants were use
Hawkes, Geoffrey E.,Lewis, David
p. 2073 - 2078
(2007/10/02)

CONDENSATION PRODUCTS OF FORMALDEHYDE
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Medevedeva, M. G.,Sukharevich, V. I.,Stanek, Ya. Ya.,Yakovlev, V. I.
p. 2525 - 2527
(2007/10/02)

SYNTHESIS OF L-IDARO-1,4-LACTONE, AN INHIBITOR OF α-L-IDOSID-URONASE
L-Idaro-1,4-lactone was synthesized by two different, published methods: (1) epimerization of monopotassium D-glucarate by refluxing in aqueous barium hydroxide, and (2) oxidation of L-iditol by heating in dilute nitric acid.The lactone, formed by heat dehydration from aqueous solution at low pH, was purified by paper chromatography, and quantitated by gas-liquid chromatography using inositol as the internal standard.The monolactone inhibited human, seminal-fluid α-L-idosiduronase activity, with either phenyl or 4-methylumbelliferyl α-L-idosiduronic acid as the substrate, to the same degree as D-glucaro-1,4-lactone inhibits α-D-glucosiduranose.
Herd, J. Kenneth,Mayberry, William R.,Snell, Robert L.
p. 33 - 40
(2007/10/02)

Synthesis of Saccharides and Related Polyhydroxylated Natural Products. 1. Simple Alditols
A new approach to sugar synthesis is demonstrated through syntheses of tetritols, pentitols, and hexitols; titanium-catalyzed asymmetric epoxidation and a new selective opening reaction of 2,3-epoxy alcohols play essential roles.
Katsuki, T.,Lee, A. W. M.,Ma, P.,Martin, V. S.,Masamune, S.,et al.
p. 1373 - 1378
(2007/10/02)

SYNTHESIS OF 2,3,4,6-TETRA-O-BENZYL-L-IDOPYRANOSE
A synthesis of 2,3,4,6-tetra-O-benzyl-L-idopyranose (15) is described, based on L-sorbose as the starting material.By a succession of well known, high-yielding procedures, the ketose was converted into a 2:1 mixture of 1,3,4,5-tetra-O-benzyl-2-O-(tert-but
Helleur, Robert,Rao, Vanga S.,Perlin, Arthur S.
p. 83 - 90
(2007/10/02)

Chemical Properties

Melting Point: 77 °C
Boiling Point: 494.9°Cat760mmHg
Flash Point:292.6°C
Density: 1.596g/cm³
Solubility:DMSO (Slightly, Sonicated), Methanol (Slightly), Water (Slightly, Sonicated)
Storage Temp.:-20°C Freezer
Vapor Pressure: 7.22E-12mmHg at 25°C
Refractive Index: -3 ° (C=1, H2O)
PSA: 121.38000
LogP: -3.58540

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Chemical Properties

Melting Point: 77 °C

Boiling Point: 494.9°Cat760mmHg

Flash Point:292.6°C

Density: 1.596g/cm³

Solubility:DMSO (Slightly, Sonicated), Methanol (Slightly), Water (Slightly, Sonicated)

Storage Temp.:-20°C Freezer

Vapor Pressure: 7.22E-12mmHg at 25°C

Refractive Index: -3 ° (C=1, H2O)

PSA: 121.38000

LogP: -3.58540

Global suppliers and manufacturers of 488-45-9total 20 suppliers on LookChem

Article Database

488-45-9

Articles about 488-45-9Total 36 be found

More Articles about upstream products of 488-45-9

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Chemical Properties

Melting Point: 77 °C

Boiling Point: 494.9°Cat760mmHg

Flash Point:292.6°C

Density: 1.596g/cm3

Solubility:DMSO (Slightly, Sonicated), Methanol (Slightly), Water (Slightly, Sonicated)

Storage Temp.:-20°C Freezer

Vapor Pressure: 7.22E-12mmHg at 25°C

Refractive Index: -3 ° (C=1, H2O)

PSA: 121.38000

LogP: -3.58540

Global suppliers and manufacturers of 488-45-9total 20 suppliers on LookChem

Density: 1.596g/cm³