- 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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- Protection-free synthesis of alkyl glycosides under hydrogenolytic conditions
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A convenient protection-free synthetic route for the preparation of alkyl glycosides has been developed. The alcoholysis of one-step preparable glycosyl donors, 4,6-dibenzyloxy-1,3,5-triazin-2-yl (DBT) glycosides, under hydrogenolytic conditions gave the corresponding glycosides in good yields without the addition of any acid promoters. The method could be successfully applied to the glycosylation of an acidlabile oligosaccharide.
- Ishihara, Masaki,Takagi, Yuka,Li, Gefei,Noguchi, Masato,Shoda, Shin-Ichiro
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supporting information
p. 1235 - 1237
(2013/10/22)
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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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- 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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- Glycosylation using unprotected alkynyl donors
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(Chemical Equation Presented) Gold(III) activation of unprotected propargyl glycosyl donors has been shown to be effective for the synthesis of saccharides. Terminal propargyl glycosides of glucose, galactose, and mannose required heating at reflux in ace
- Mamidyala, Sreeman K.,Finn
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experimental part
p. 8417 - 8420
(2010/01/16)
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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 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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- Preparation of New Terpenyl β-D-Glucopyranosides by a Modified Koenigs-Knorr Procedure.
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Ten new hemi- and monoterpenyl β-D-glucopyranosides have been prepared by a modification of the Koenigs-Knorr procedure which utilises silver fluoroacetate as a soluble catalyst coupled with the introduction of a basic ion-exchange resin to effect the deacetylation step.Most of these compounds could not be obtained in acceptable yields using the classical procedure.
- Ackermann, Irmtraud E.,Banthorpe, Derek V.,Fordham, William D.,Kinder, John P.,Poots, Ian
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- Enzymic Formation of β-Alkyl Glycosides by β-Galactosidase from Aspergillus oryzae and Its Application to the Synthesis of Chemically Unstable Cardiac Glycosides
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β-Galactosidase obtained from Aspergillus oryzae was found to have strong transglycosylation activity.The glycosylation of water-soluble and insoluble alcohols was successfully performed under mild conditions (pH 5 at 4-37 deg C) with this enzyme.The enzyme was also applied to the one-step synthesis of several cardiac glycosides that are difficult to obtain by ordinary chemical methods.Keywords--enzymic transglycosylation; β-galactosidase; Aspergillus oryzae; cardiac glycoside; alkyl β-glycoside
- Ooi, Yasuhiro,Hashimoto, Toshihiro,Mitsuo, Naoki,Satoh, Toshio
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p. 1808 - 1814
(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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