- Selective Primary Alcohol Oxidation of Lignin Streams from Butanol-Pretreated Agricultural Waste Biomass
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Chemically modified lignins are important for the generation of biomass-derived materials and as precursors to renewable aromatic monomers. A butanol-based organosolv pretreatment has been used to convert an abundant agricultural waste product, rice husks, into a cellulose pulp and three additional product streams. One of these streams, a butanol-modified lignin, was oxidized at the γ position to give a carboxylic acid functionalized material. Subsequent coupling of the acid with aniline aided lignin characterization and served as an example of the flexibility of this approach for grafting side chains onto a lignin core structure. The pretreatment was scaled up for use on a multi-kilogram scale, a development that enabled the isolation of an anomeric mixture of butoxylated xylose in high purity. The robust and scalable butanosolv pretreatment has been developed further and demonstrates considerable potential for the processing of rice husks.
- Panovic, Isabella,Lancefield, Christopher S.,Phillips, Darren,Gronnow, Mark J.,Westwood, Nicholas J.
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p. 542 - 548
(2019/01/14)
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- Preparation of salidroside with n-butyl β-D-glucoside as the glycone donor via a two-step enzymatic synthesis catalyzed by immobilized β-glucosidase from bitter almonds
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β-Glucosidase from bitter almonds was immobilized on epoxy group-functionalized beads for catalyzing salidroside synthesis in a two-step process with n-butyl-β-D-glucoside (BG) as the glucosyl donor. The formation of salidroside ((0.59 ± 0.02) M) at a yield of 39.04%±1.25% was accomplished in 8 h by the transglucosylation of immobilized β-glucosidase at pH?8.0 and 50 °C when the ratio of BG to tyrosol was 1:2 (mol/mol). A study on the influence of different glycosyl acceptors demonstrated that the yield of the glucosylation reaction of phenylmethanol and cyclohexanol was higher than that of either phenol or cyclohexanol. This may account for the selectivity of the immobilized enzyme towards the alcoholic hydroxyl group of tyrosol in the salidroside synthesis reaction. A study on the synthesis of BG via the reverse hydrolysis of immobilized β-glucosidase showed that a yield of 78.04%±2.2% BG can be obtained with a product concentration of (0.23 ± 0.015) M.
- Wang, Feng,Huang, Dengfa,Ma, Yong,Zhang, Fuming,Linhardt, Robert J.
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p. 246 - 260
(2019/02/03)
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- Influence of acyl groups on glucopyranoside reactivity in Lewis acid promoted anomerisation
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Lewis acid promoted anomerisation has potential in O- or S-glycoside synthesis. Herein, the anomerisation kinetics of thirty-one β-D-glucopyranosides was determined to determine how particular acyl protecting groups and their location influence reactivity towards a Lewis acid promoted reaction. The replacement of acetyl groups with benzoyl groups led to reduced reactivity when located at O-3, O-4 and O-6. However a reactivity increase was observed when the acetyl group was replaced by a benzoyl group at O-2. The 2,3,4,6-tetra-O-(4-methoxy)benzoate had an ~2-fold increase in rate when compared to the tetrabenzoate.
- Farrell, Mark P.,Doyle, Lisa M.,Murphy, Paul V.
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supporting information
p. 2726 - 2731
(2018/06/20)
-
- ALKENYL GLYCOSIDES AND THEIR PREPARATION
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An alkenyl glycoside is prepared by reacting a metathesis-derived unsaturated fatty alcohol containing 10 to 30 carbon atoms with either (1) a reducible monosaccharide or composition hydrolyzable to a reducible monosaccharide, or (2) a hydrocarbyl glycoside produced by reacting an alcohol containing up to 6 carbon atoms with a reducible monosaccharide or composition hydrolyzable to a reducible monosaccharide. Each of these reactions is performed in the presence of an acid catalyst and under conditions sufficient to form the alkenyl glycoside or hydrocarbyl glycoside. The preferred alkenyl glycosides are 9-decen-1-yl glycoside; 9-dodecen-1-yl glycoside; 9-tridecen-1-yl glycoside; 9-pentadecen-1-yl glycoside; 9-octadecen-yl glycoside; or 9-octadecen-1,18-diyl glycoside.
- -
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Paragraph 0088
(2014/09/30)
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- Significantly Improved Equilibrium Yield of Long-Chain Alkyl Glucosides via Reverse Hydrolysis in a Water-Poor System Using Cross-Linked Almond Meal as a Cheap and Robust Biocatalyst
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An array of ten β-D-glucopyranosides with varied alkyl chain lengths were enzymatically synthesized. It was found that for longer alkyl chains a lower initial rate and final yield of glucoside was obtained except for methyl glucoside because of the severe toxicity of methanol to the enzyme. From a thermodynamics point of view, the equilibrium constant and Gibbs free energy variation of the glucoside syntheses were systematically investigated. To improve the final yields of the glucosides containing long alkyl chains the equilibrium of the enzymatic glucoside synthesis was altered. The equilibrium yield of decyl β-D-glucoside increased from 1.9% to 6.1% when the water content was reduced from 10% to 5% (v/v) using tert-butanol as a cosolvent and 0.10 mol/L of glucose as a substrate. As for the other longer alkyl chain glucosides, heptyl β-D-glucoside was found to have significant surface activity as well.
- Wang, Qinqqin,Yu, Huilei,Zhao, Na,Li, Chunxiu,Shang, Yazhuo,Liu, Honglai,Xu, Jianhe
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p. 275 - 280
(2016/04/10)
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- Significantly improved equilibrium yield of long-chain alkyl glucosides via reverse hydrolysis in a water-poor system using cross-linked almond meal as a cheap and robust biocatalyst
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An array of ten β-D-glucopyranosides with varied alkyl chain lengths were enzymatically synthesized. It was found that for longer alkyl chains a lower initial rate and final yield of glucoside was obtained except for methyl glucoside because of the severe toxicity of methanol to the enzyme. From a thermodynamics point of view, the equilibrium constant and Gibbs free energy variation of the glucoside syntheses were systematically investigated. To improve the final yields of the glucosides containing long alkyl chains the equilibrium of the enzymatic glucoside synthesis was altered. The equilibrium yield of decyl β-D-glucoside increased from 1.9 to 6.1 when the water content was reduced from 10 to 5 (v/v) using tert-butanol as a cosolvent and 0.10 mol/L of glucose as a substrate. As for the other longer alkyl chain glucosides, heptyl β-D-glucoside was found to have significant surface activity as well.
- Wang, Qinqqin,Yu, Huilei,Zhao, Na,Li, Chunxiu,Shang, Yazhuo,Liu, Honglai,Xu, Jianhe
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p. 275 - 280
(2012/06/29)
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- Purification, characterization, and gene identification of an α-glucosyl transfer enzyme, a novel type α-glucosidase from Xanthomonas campestris WU-9701
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The α-glucosyl transfer enzyme (XgtA), a novel type α-glucosidase produced by Xanthomonas campestris WU-9701, was purified from the cell-free extract and characterized. The molecular weight of XgtA is estimated to be 57 kDa by SDS-PAGE and 60 kDa by gel filtration, indicating that XgtA is a monomeric enzyme. Kinetic properties of XgtA were determined for α-glucosyl transfer and maltose-hydrolyzing activities using maltose as the α-glucosyl donor, and if necessary, hydroquinone as the acceptor. The Vmax value for α-glucosyl transfer activity was 1.3 × 10-2 (mM/s); this value was 3.9-fold as much as that for maltose-hydrolyzing activity. XgtA neither produced maltooligosaccharides nor hydrolyzed sucrose. The gene encoding XgtA that contained a 1614-bp open reading frame was cloned, identified, and highly expressed in Escherichia coli JM109 as the host. Site-directed mutagenesis identified Asp201, Glu270, and Asp331 as the catalytic sites of XgtA, indicating that XgtA belongs to the glycoside hydrolase family 13.
- Sato, Toshiyuki,Hasegawa, Nobukazu,Saito, Jun,Umezawa, Satoru,Honda, Yuki,Kino, Kuniki,Kirimura, Kohtaro
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body text
p. 20 - 27
(2012/09/05)
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- Isolation and characterization of a novel α-glucosidase with transglycosylation activity from Arthrobacter sp. DL001
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A strain of Arthrobacter sp. DL001 with high transglycosylation activity was successfully isolated from the Yellow Sea of China. To purify the extracellular enzyme responsible for transglycosylation, a four-step protocol was adopted and the enzyme with electrophoretical purity was obtained. The purified enzyme has a molecular mass of 210 kDa and displays a narrow hydrolysis specificity towards α-1,4-glucosidic bond. Its hydrolytic activity was identified as decreasing in the order of maltotriose > panose > maltose. Only 3.61% maltose activity occurs when p-nitrophenyl α-d-glycopyranoside serves as a substrate, suggesting that this enzyme belongs to the type II α-glucosidase. In addition, the enzyme was able to transfer glucosyl groups from the donors containing α-1,4-glucosidic bond specific to glucosides, xylosides and alkyl alcohols in α-1,4- or α-1,6-manners. A decreased order of activity was observed when maltose, maltotriose, panose, β-cyclodextrin and soluble starch served as glycosyl donors, respectively. When maltose was utilized as a donor and a series of p-nitrophenyl-glycosides as acceptors, the glucosidase was capable of transferring glucosyl groups to p-nitrophenyl-glucosides and p-nitrophenyl-xylosides in α-1,4- or α-1,6-manners. The yields of p-nitrophenyl-oligosaccharides could reach 42-60% in 2 h. When a series of alkyl alcohols were utilized as acceptors, the enzyme exhibited its transglycosylation activities not only to the primary alcohols but also to the secondary alcohols with carbon chain length 1-4. Therefore, all the results indicated that the purified α-glucosidase present a useful tool for the biosynthesis of oligosaccharides and alkyl glucosides.
- Zhou, Kun,Luan, Hong-Wei,Hu, Ying,Ge, Guang-Bo,Liu, Xing-Bao,Ma, Xiao-Chi,Hou, Jie,Wang, Xiu-Li,Yang, Ling
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experimental part
p. 48 - 57
(2012/09/07)
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- Green glycosylation promoted by reusable biomass carbonaceous solid acid: An easy access to β-stereoselective terpene galactosides
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An efficient green protocol has been developed for the atom economic glycosylation of unprotected, unactivated glycosyl donors and glycosylation of glycosyl trichloroacetimidates with the aid of reusable eco-friendly biomass carbonaceous solid acid as catalyst. The Royal Society of Chemistry.
- Gorityala, Bala Kishan,Ma, Jimei,Pasunooti, Kalyan Kumar,Cai, Shuting,Liu, Xue-Wei
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supporting information; experimental part
p. 573 - 577
(2011/05/06)
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- Efficient glycosylation of unprotected sugars using sulfamic acid: A mild eco-friendly catalyst
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Sulfamic acid, a mild and environmentally benign catalyst has been successfully used in the Fischer glycosylation of unprotected sugars for the preparation alkyl glycosides. A diverse range of aliphatic alcohols have been used to prepare a series of alkyl glycosides in good to excellent yield.
- Guchhait, Goutam,Misra, Anup Kumar
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experimental part
p. 52 - 57
(2012/01/15)
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- Cellulose conversion into alkylglycosides in the ionic liquid 1-butyl-3-methylimidazolium chloride
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The conversion of cellulose into alkylglycosides is carried out in the ionic liquid 1-butyl-3-methylimidazolium chloride in the presence of an acidic catalyst. Primary alcohols like n-butanol and n-octanol were used as alkylating reagents. The acidic resin Amberlyst 15DRY proved to be the optimum heterogeneous catalyst: it catalyzes the hydrolysis of the β(1→4) links in the cellulose polymeric chain as well as the alkylation of the hydroxyl groups at the C1 position of the glucose intermediate. The cellulose was fully converted under mild conditions; in a reaction with n-butanol, the obtained yield of butylglucopyranoside isomers was 86%.
- Ignatyev, Igor A.,Mertens, Pascal G. N.,Van Doorslaer, Charlie,Binnemans, Koen,De Vos, Dirk E.
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scheme or table
p. 1790 - 1795
(2011/02/21)
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- POLYMER STABILIZER
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A polymer stabilizer comprising the following alkoxy compound: the alkoxy compound: a compound obtained by alkoxylating at least one hydroxyl group contained in a compound of the following formula (1) containing one formyl group or carbonyl group and (n?1) hydroxyl groups in the molecule with an alkyl group having 1 to 12 carbon atoms: [in-line-formulae]CnH2nOn??(1)[/in-line-formulae] (wherein, n represents an integer of 3 or more).
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- SnCl4- and TiCl4-catalyzed anomerization of acylated O - And S -glycosides: Analysis of factors that lead to higher α: β d reaction rates
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The quantification of factors that influence both rates and stereoselectivity of anomerization reactions catalyzed by SnCl4 and TiCl4 and how this has informed the synthesis of α-O- and α-S-glycolipids is discussed. The SnCl4-catalyzed anomerization reactions of β-S- and β-O-glycosides of 18 substrates followed first order equilibrium kinetics and kf + kr values were obtained, where kf is the rate constant for the forward reaction (β → α) and kr is the rate constant for the reverse reaction (α → β). Comparison of the kf + k r values showed that reactions of glucuronic acid or galacturonic acid derivatives were ~10 to 3000 times faster than those of related glucoside and galactopyranoside counterparts and α:β ratios were generally also higher. Stereoelectronic effects contributed from galacto-configured compounds were up to 2-fold faster than those of corresponding glucosides. The introduction of groups, including protecting groups, which are increasingly electron releasing generally led to rate enhancements. The anomerization of S-glycosides was consistently faster than that of corresponding O-glycosides. Reactions were generally faster for reactions with TiCl4 than those with SnCl4. Anomeric ratios depended on the Lewis acid, the number equivalents of the Lewis acid, temperature, and substrate. Very high ratios of α-products for both O- and S-glucuronides were observed for reactions promoted by TiCl4; for these substrates TiCl4 was superior to SnCl4. Anomeric ratios from anomerization of S-glucosides were higher with SnCl4 than with TiCl4. The dependence of equilibrium ratio on Lewis acid and the number of equivalents of Lewis acid indicated that the equilibrium ratio is determined by a complex of the saccharide residue bound to the Lewis acid and not the free glycoside. The high α:β ratios observed for anomerization of both O- and S-glycuronic acids can be explained by coordination of the C-1 heteroatom and C-6 carbonyl group of the product to the Lewis acid, which would enhance the anomeric effect by increasing the electron-withdrawing ability of the anomeric substituent and lead to an increase in the proportion of the α-anomer. Such an observation would argue against the existence of a reverse anomeric effect. Support for a chelation-induced endocyclic cleavage mechanism for the anomerization is provided by the trapping of a key intermediate. The data herein will help predict the tendency of β-glycosides to undergo anomerization; this includes cases where 1,2-trans glycosides are initial products of glycosidation reactions catalyzed by TiCl4 or SnCl4.
- Pilgrim, Wayne,Murphy, Paul V.
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supporting information; experimental part
p. 6747 - 6755
(2010/12/25)
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- Ionic liquid promoted atom economic glycosylation under Lewis acid catalysis
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Straightforward glycosylation of various alcohols with unprotected and non-activated monosaccharides were performed under scandium triflate catalysis. Rate and yield of glycosylation were highly improved when using 1-butyl-3-methylimidazolium trifluoromethanesulfonate as a green solvent. This ionic liquid was allowed to be recycled at least three times without loss of activity. The possibility of drastically reducing the amounts of catalyst (down to 1 mol%) and aglycone (down to 1 equiv) when performing the reaction in ionic liquid opens new perspectives in O-glycosylation, as a direct coupling between an aglycone and free sugars.
- Auge, Jacques,Sizun, Gwenaelle
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scheme or table
p. 1179 - 1183
(2010/05/02)
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- A new method of synthesis of alkyl β-glycosides using sucrose as sugar donor
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Cellobiose phosphorylase from Clostridium thermocellum catalyzed the β-anomer-selective synthesis of alkyl glucosides from cellobiose. Synthesis of alkyl β-glucoside from inexpensive sucrose using cellobiose phosphorylase and sucrose phosphorylase from Pseudomonas saccharophilia was investigated. By combined use of these two phosphorylases, alkyl β-glucoside was anomer-selectively synthesized from sucrose and alkyl alcohol.
- Kino, Kuniki,Satake, Ryoko,Morimatsu, Takayuki,Kuratsu, Shoko,Shimizu, Yu,Sato, Masaru,Kirimura, Kohtaro
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p. 2415 - 2417
(2008/12/23)
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- Novel reaction systems for the synthesis of O-glucosides by enzymatic reverse hydrolysis
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Our studies are presented to replace alcohols as solvents in reverse hydrolytic reactions catalyzed by immobilized β-glucosidase to synthesize O-substituted β-D-glucopyranosides in preparative-scale. We found that 1,2-diacetoxyethane is a suitable solvent and O-alkyl or aryl β-D-glucosides were synthesized in moderate yields (after isolation 12-19%). In these reactions proportion of glucose and glucosyl acceptor hydroxy compounds was 1:20. We suggest that 1,2-diacetoxyethane can be useful not only for alcohols but for other glucosyl donor compounds unsuitable for the role of solvent (e.g., phenols) in the synthesis of O-β-D-glucosides by reverse hydrolysis.
- Balogh, Teréz,Boross, László,Kosáry, Judit
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p. 679 - 682
(2007/10/03)
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- Synthesis of C7-C16-alkyl glycosides: Part I - Synthesis of alkyl D-glucopyranosides in the presence of tin (IV) chloride as a Lewis acid catalyst
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The Lewis acid catalyzed glycosylation reaction of β-peracetylated sugar derivative (glucose) with fatty alkanols is used in a synthesis of C7-C16-alkyl glucopyranosides. The process occurs under the influence of tin (IV) chloride.
- Konstantinovic,Predojevic,Mojsilovic,Dimitrijevic,Milosevic
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p. 796 - 801
(2007/10/03)
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- Microwave-assisted synthesis of alkyl glycosides
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The reaction of sugars with alcohols and catalytic amounts of an acid in a high frequency field (2.45 GHz) leads to high yields of the corresponding alkyl glycosides. The ratio of the α/β-anomers is influenced by the reaction conditions and reaction controlling.
- Nuechter,Ondruschka,Lautenschlaeger
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p. 1277 - 1283
(2007/10/03)
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- Synthesis of butyl-α and β-D-glucopyranosides in the presence of dealuminated H-Y faujasites: Kinetic study, mechanism, stereoelectronic effects, and microreversibility principle
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The glycosylation reaction between D-glucose and n-butanol has been investigated over various dealuminated HY zeolites with Si/Al ratios from 2.5 to 100. In this way, butyl-α- and β-D-glucofuranosides and -pyranosides are readily synthesized at temperatures from 363 to 383 K and with a butanol/glucose ratio from 5 to 40. From the systematic study of the glycosylation reaction, a kinetic scheme involving both consecutive and competitive steps has been proposed. Butyl-D-glucofuranosides and butyl-D-glucopyranosides are primary products, butyl-D-glucofuranosides being then quantitatively converted into their pyranoside form. The use of microporous catalysts, associated with their shape selectivity properties, reduces the amount of oligomers and increases the amount of β-D-glucopyranosides in a significant manner. The β/α anomeric ratios observed are then discussed in terms of stereoelectronic effects which are, according to the principle of microreversibility of the same nature as those reported for the reverse reaction, i.e., hydrolysis of alkyl-D-glucopyranosides.
- Chapat, Jean-Francois,Finiels, Annie,Joffre, Jacques,Moreau, Claude
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p. 445 - 453
(2007/10/03)
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- Synthesis of detergent O-glucosides by reverse hydrolysis in alcohol- water biphasic systems using α- and β-glucosidases
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The α- and β-glucosidases showed significant O-glycosylation activity with glucose as substrate and with different alcohols both as reaction partners and solvents in reverse hydrolytic processes. With native glucosidases upscaling resulted in low yields due to heterogeneity of reaction mixtures. Immobilization of the enzymes on a modified polyacrylamide-type bead support (Acrylex C-100) increased enzyme stability resulting in higher yields and permitted to perform glucosylations on a larger scale. From these experiments O-alkyl glucosides were isolated in moderate yields.
- Kosary, Judit,Stefanovits-Banyai,Boross
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p. 611 - 613
(2007/10/03)
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- Gemini surfactants from alkyl glucosides
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1,5-Bis-[6-O-(n-butyl α-D-glucopyranosid)] glutarate 7 was synthesized starting from D-glucose by a simple procedure. The anomeric mixture of alkylglucosides was separated by flash chromatography of their peracetates. Detritylation in neutral conditions is described. This is the first example of a non ionic gemini surfactant where alkyl glucosides are linked through a spacer at C-6.
- Castro, Mariano J. L.,Kovensky, Jose,Fernandez Cirelli, Alicia
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p. 3995 - 3998
(2007/10/03)
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- Regiospecific enzymic acylation of butyl α-D-glucopyranoside
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Acylated sugars are important sources of surfactants and pharmaceutical materials. Regioselective acylation is necessary for the synthesis of carbonhydrate derivatives where selective protection and deprotection of hydroxyl groups is critical. The authors report reaction conditions that lead to high yields of diesters in a regiospecific manner. The esters were obtained in high yield by enzymic reverse hydrolysis which involved the azeothropic removal of water from mixtures of the acid and substrate in hexane. The use of an apolar solvent such as hexane limits acyl-group migration. The purity of the products was determined by GLC after silylation and characterized on the basis of 13C NMR data.
- Fabre,Betbeder,Paul,Monsan,Perie
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p. 407 - 411
(2007/10/02)
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- Enzyme-catalysed synthesis of alkyl β-D-Glucosides in organic media
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The synthetic potential of Almond β-D-Glucosidase for the synthesis of alkyl glucosides was studied. The regio and stereoselectivity of the synthesis were analysed for the reverse hydrolysis and the transglucosylation methods in tert-butanol and acetonitrile media.
- Vic, Gabin,Thomas, Daniel
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p. 4567 - 4570
(2007/10/02)
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- KINETICS AND MECHANISM OF THE ACID-CATALYSED BUTANOLYSIS OF 1,6-ANHYDRO-β-D-GLUCOPYRANOSE
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The sulfuric acid-catalysed reaction of 1,6-anhydro-β-D-glucopyranose in 1-butanol at 80 deg C gave butyl α- and β-D-glucopyranoside as the sole products.The initial kinetic α/β ratio was 1.5, and the final α/β ratio upon equilibration was 2.7.The four pseudo-first-order reaction rate constants involved have been determined.Conformational studies showed that the reaction probably proceeds via a 1C4-Bo.3 interconversion of 1,6-anhydro-β-D-glucopyranose and a 4H3-like oxycarbonium species.
- Straathof, Adrie J. J.,Vrolijk, Johannes M.,Bekkum, Herman van,Kieboom, Antonius P. G.
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p. 163 - 170
(2007/10/02)
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- Synthesis of β-Alkyl Glucosides by Enzymic Transglucosylation
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Lactase from Kluyveromyces lactis was found to have high transglucosylation activity, transferring the glucosyl group of aryl glucoside to an alcoholic hydroxyl group in high yield.Both primary and secondary alcohols can accept the glucosyl group.Transglucosylation to glycol yielded a single kind of glucoside.A very hydrophilic alcohol, such as glycerol, could not serve as a substrate in this system.Hydrophobic alcohols slightly soluble in water were glucosylated in a two-phase system consisting of water and an organic solvent immiscible with water.Keywords - transglucosylation; transglycosylation; β-glucoside; lactase; Kluyveromyce s lactis; phenyl β-D-glucopyranoside; hydrophobic alcohol; two-phase system; alkyl glucoside; enzymic transglucosylation
- Mitsuo, Naoki,Takeichi, Hiroshi,Satoh, Toshio
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p. 1183 - 1187
(2007/10/02)
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