- Synthesis of glycotriazololipids and observations on their self-assembly properties
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Abstract Various carbohydrate-anchored triazole-linked lipids prepared by solvent-free mechanochemical azide-alkyne click reaction, on analysis by TEM, have been found to spontaneously self-assemble in solvents leading to structures of interesting physicochemical attributes. Interestingly, analogous compounds based on different sugars (e.g., d-glucose, and d-galactose, as also d-lactose) assemble in patterns distinctly different from each other thus reiterating the fact that the structure of the sugar as well as that of the lipid are important factors that determine the size and shape of the supramolecular assembly formed. Besides, the molecular self-assembly was also found to be solvent-as well as temperature-dependent.
- Tyagi, Mohit,Kartha, K.P. Ravindranathan
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supporting information
p. 85 - 92
(2015/06/30)
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- Chemoenzymatic synthesis of β-D-glucosides using cellobiose phosphorylase from Clostridium thermocellum
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Abstract Over the past decade, disaccharide phosphorylases have been successfully applied for the synthesis of numerous α-glucosides. In contrast, much less research has been done with respect to the production of β-glucosides. Although cellobiose phosphorylase was already successfully used for the synthesis of various disaccharides and branched trisaccharides, its glycosylation potential towards small organic compounds has not been explored to date. Unfortunately, disaccharide phosphorylases typically have a very low affinity for non-carbohydrate acceptors, which urges the addition of solvents. The ionic liquid AMMOENGTM 101 and ethyl acetate were identified as the most promising solvents, allowing the synthesis of various β-glucosides. Next to hexyl, heptyl, octyl, nonyl, decyl and undecyl β-D-glucopyranosides, also the formation of vanillyl 4-O-β-D-glucopyranoside, 2-phenylethyl β-D-glucopyranoside, β-citronellyl β-D-glucopyranoside and 1-O-β-D-glucopyranosyl hydroquinone was confirmed by nuclear magnetic resonance spectroscopy and mass spectrometry. Moreover, the stability of cellobiose phosphorylase could be drastically improved by creating cross-linked enzyme aggregates, while the efficiency of the biocatalyst for the synthesis of octyl β-D-glucopyranoside was doubled by imprinting with octanol. The usefulness of the latter system was illustrated by performing three consecutive batch conversions with octanol imprinted cross-linked enzyme aggregates, yielding roughly 2 g of octyl β-D-glucopyranoside.
- De Winter, Karel,Van Renterghem, Lisa,Wuyts, Kathleen,Pelantová, Helena,K?en, Vladimír,Soetaert, Wim,Desmet, Tom
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p. 1961 - 1969
(2015/06/02)
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- Preparation of two glycoside hydrolases for use in micro-aqueous media
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Enzymatic synthesis of alkyl glycosides using glycoside hydrolases is well studied, but has yet to reach industrial scale, primarily due to limited yields. Reduced water content should increase yields by limiting the unwanted hydrolytic side reaction. However, previous studies have shown that a reduction in water content surprisingly favors hydrolysis over transglycosylation. In addition, glycoside hydrolases normally require a high degree of hydration to function efficiently. This study compares six enzyme preparation methods to improve resilience and activity of two glycoside hydrolases from Thermotoga neapolitana (TnBgl3B and TnBgl1A) in micro-aqueous hexanol. Indeed, when adsorbed onto Accurel MP-1000 both enzymes increasingly favored transglycosylation over hydrolysis at low hydration, in contrast to freeze-dried or untreated enzyme. Additionally, they displayed 17-70× higher reaction rates compared to freeze-dried enzyme at low water activity, while displaying comparable or lower activity for fully hydrated systems. These results provide valuable information for use of enzymes under micro-aqueous conditions and build toward utilizing the full synthetic potential of glycoside hydrolases.
- Lundemo, Pontus,Karlsson, Eva Nordberg,Adlercreutz, Patrick
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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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- 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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- 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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- Chemoenzymatic synthesis of n-hexyl and O-β-D-xylopyranosyl-(1→6) -β-D-glucopyranosides
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Direct β-glucosidation between 1,6-octanediol (5) and D-glucose (3) using the immobilized β-glucosidase (EC 3.2.1.21) from almonds with the synthetic prepolymer ENTP-4000 gave a mono-β-glucoside (6) in 61.4% yield, which was converted into the n-hexyl β-D
- Kishida, Masashi,Nishiuchi, Miho,Kato, Keisuke,Akita, Hiroyuki
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p. 1105 - 1108
(2007/10/03)
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- Preparation of alkyl α- and β-D-glucopyranosides, thermotropic properties and X-ray analysis
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Monohydrates of heptyl to decyl α-D-glucopyranosides as obtained from product mixtures of the Fischer glucosylation were crystallized from water at the Krafft point. The results of the single-crystal X-ray analysis of anhydrous α anomers and their monohydrates provide for a better understanding of crystal formation and stability of their hydrates. The preparation of alkyl β-D-glucopyranosides-without concomitant formation of α anomers as by-products-has been described. The thermotropic properties have been investigated for the α compounds and their monohydrates, and for the β-D-glucopyranosides. Copyright (C) 1998 Elsevier Science Ltd.
- Adasch, Volker,Hoffmann, Bettina,Milius, Wolfgang,Platz, Gerhard,Voss, Gundula
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p. 177 - 187
(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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- 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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