- Sweet surfactants: Packing parameter-invariant amphiphiles as emulsifiers and capping agents for morphology control of inorganic particles
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Surfactants are not only pivotal constituents in any biological organism in the form of phospholipids, they are also essential for numerous applications benefiting from a large, internal surface, such as in detergents, for emulsification purposes, phase transfer catalysis or even nanoparticle stabilization. A particularly interesting, green class of surfactants contains glycoside head groups. Considering the variability of glycosides, a large number of surfactant isomers become accessible. According to established models in surfactant science such as the packing parameter or the hydrophilic lipophilic balance (HLB), they do not differ from each other and should, thus, have similar properties. Here, we present the preparation of a systematic set of glycoside surfactants and in particular isomers. We investigate to which extent they differ in several key features such as critical aggregation concentration, thermodynamic parameters, etc. Analytical methods like isothermal titration calorimetry (ITC), tensiometry, dynamic light scattering (DLS), small angle-X-ray scattering (SAXS), transmission electron microscopy (TEM) and others were applied. It was found that glycosurfactant isomers vary in their emulsification properties by up to two orders of magnitude. Finally, we have investigated the role of the surfactants in a microemulsion-based technique for the generation of zinc oxide (ZnO) nanoparticles. We found that the choice of the carbohydrate head has a marked effect on the shape of the formed inorganic nanocrystals.
- Voggel, Michael,Meinusch, Rebecca M.,Siewert, Vanessa,Kunkel, Marius,Wittmann, Valentin,Polarz, Sebastian
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p. 7214 - 7227
(2018/09/26)
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- Boronic Acids as Phase-Transfer Reagents for Fischer Glycosidations in Low-Polarity Solvents
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Protocols employing phenylboronic acid as a phase-transfer reagent for Fischer glycosidations in low-polarity organic solvents are described. In addition to providing rate acceleration, the formation of a substrate-derived boronic ester alters the course of the reaction by selective promotion of a furanoside- or pyranoside-selective pathway. Computational modeling of the relative energies of the glycoside-derived boronic esters provides results that are qualitatively consistent with the observed distributions of furanoside versus pyranoside products. The boronic esters that are obtained as direct products of these reactions serve as protected intermediates for the synthesis of functionalized glycosides. Complexation of particular diol groups by the boronic acid also enables selective transformations of mixtures of carbohydrates.
- Manhas, Sanjay,Taylor, Mark S.
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p. 11406 - 11417
(2017/11/10)
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- Protecting group-free immobilization of glycans for affinity chromatography using glycosylsulfonohydrazide donors
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A variety of applications in glycobiology exploit affinity chromatography through the immobilization of glycans to a solid support. Although several strategies are known, they may provide certain advantages or disadvantages in how the sugar is attached to
- Hernandez Armada, Daniel,Santos, Jobette T.,Richards, Michele R.,Cairo, Christopher W.
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p. 109 - 116
(2015/10/19)
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- Polyvinyl trisulfonate ethylamine based solid acid catalyst for the efficient glycosylation of sugars under solvent free conditions
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Heterogeneous Bronsted solid acid catalysts have the potential to decrease the environmental impact related to chemical production. Herein, we have synthesized polyvinyl bound trisulfonate ethylamine chloride (PV-THEAC) and polyvinyl bound disulfonate ethylamine (PV-DSEA) as Bronsted solid acid catalysts which exhibited effective catalytic activity for acid catalyzed glycosylation reactions with sugar derivatives. In particular, 0.3 equiv. of the PV-THEAC catalyst was found to be the most efficient and a reusable catalyst for glycosylation reactions. A high density of the trisulfonic group (-OSO3H) contributed to the excellent catalytic activity during glycosylation. Moreover, glycosylation reactions with d-mannose, d-xylose and d-glucose have been studied with alcohol. Remarkable acceleration of the glycosylation reaction using a glycosyltrichloroacetimidate donor was obtained with the selective production of β-glycoside.
- Chaugule, Avinash A.,Jadhav, Amol R.,Kim, Hern
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p. 104715 - 104724
(2015/12/30)
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- Exploring the meaning of sugar configuration in a supramolecular environment: Comparison of six octyl glycoside micelles by ITC and NMR spectroscopy
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A series of octyl α- and β-glycosides of the manno- galacto- and gluco-series were synthesized and employed in formation of homo- and hetero-micelles in water. Critical micelle concentrations (cmc), thermodynamic quantities of demicellation and, to some extent, the hydrodynamic radii of glycomicelles were determined by isothermal titration calorimetry (ITC) and diffusion NMR studies. The goal of this work was to determine the significance of anomeric configuration as well as of epimerisation at the sugar ring for supramolecular features of the respective glycoside. A new projection of glycoside structures is proposed to facilitate interpretation of structure-property relationships in this regard. This journal is the Partner Organisations 2014.
- Schmidt-Lassen, J?rn,Lindhorst, Thisbe K.
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supporting information
p. 1218 - 1226
(2014/08/05)
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- Glycosylation mediated - BAIL in aqueous solution
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The use of Br?nsted acid ionic liquid (BAIL) as a catalyst for the activation of unreactive and unprotected glycosyl donors has been demonstrated for the first time in aqueous solution.
- Delacroix, Sébastien,Bonnet, Jean-Pierre,Courty, Matthieu,Postel, Denis,Van Nhien, Albert Nguyen
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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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- 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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- Molecular recognition of carbohydrates with acyclic pyridine-based receptors
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The recognition capabilities of acyclic pyridine-based receptors toward monosaccharides were evaluated. Aminopyridine receptors based on the 2,4,6-trimethyl- or 2,4,6-triethylbenzene frame show high β vs α binding selectivity in the recognition of glucopyranosides. Amidopyridine receptors, which are sterically less hindered at nitrogen, display high efficiency and an inverse selectivity. The 2-aminopyridine group has been established as a highly effective recognition group in the binding of monosaccharides. The factors influencing the binding properties of receptors 1-15, which differ in the nature and number of binding and spacer subunits used as the buildings blocks, are discussed.
- Mazik, Monika,Radunz, Wolfgang,Boese, Roland
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p. 7448 - 7462
(2007/10/03)
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- A simple polar deacetylated caloporoside derivative is a positive modulator of the GABA(A) chloride channel complex in cortical mammalian neurones
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Synthesis of octyl-O-β-D-mannopyranoside, a caloporoside analogue was achieved by the activation of 2,3,4,6-tetra-O-benzyl-1-O-1',3'2'-dioxaphosphacy clohexane-α,β-D-mannopyranosyl-2-oxide with TMSOTf (Trimethyl silyl triflate) and subsequent debenzylation. At 100 μM the molecule significantly and reversibly increased the magnitude of GABA(A) currents evoked in cultured rat pyramidal neurones whilst concomitantly reducing the incidence of spontaneous synaptic activity. These results contradict earlier proposals that such molecules bind to the TBPS (tert-Butylbicyclophosphorothionate) site to block the chloride channel. (C) 2000 Elsevier Science Ltd. All rights reserved.
- Lees, George,Chazot, Paul L.,Vankayalapati, Hariprasad,Singh, Gurdial
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p. 1759 - 1761
(2007/10/03)
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