References of "Nicks, Francois"
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See detailAmphiphilic structure-surface property relationships of monosaccharide-based surfactants
Razafindralambo, Hary ULg; Nicks, Francois ULg; Richard, Gaetan ULg et al

Poster (2013, April 08)

A set of monosaccharide-based renewable surfactants has been prepared, structurally checked, and systematically screened for different activities and functionalities. These compounds vary in the polar ... [more ▼]

A set of monosaccharide-based renewable surfactants has been prepared, structurally checked, and systematically screened for different activities and functionalities. These compounds vary in the polar head group, linker, and hydrophobic tail. Beyond the goal to find out the most potential valuable surfactants for each measurement, relationships between chemical structure, basic properties, and functionalities have been examined by comparing compounds differing in a single structural variable. In this paper, we show and explain the impact of the anomeric alpha or bêta, neutral or acid sugar derivatives, equatorial or axial position of hydroxyl group, alkyl chain substitute attachment position, number, and length on surface properties of sugar-based surfactants. [less ▲]

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See detailStudy of the Influence of Pure Ionic Liquids on the Lipase-catalyzed (Trans)esterification of Mannose Based on their Anion and Cation Nature
Galonde, Nadine ULg; Nott, Katherine ULg; Richard, Gaetan ULg et al

in Current Organic Chemistry (2013), 17(7), 763-770

A screening of nine ionic liquids (ILs) has been carried out in order to study the influence of the anion's and cation's nature and structure on the synthesis of mannosyl myristate by (trans ... [more ▼]

A screening of nine ionic liquids (ILs) has been carried out in order to study the influence of the anion's and cation's nature and structure on the synthesis of mannosyl myristate by (trans)esterification catalyzed by Novozym® 435. The best ILs in terms of yield (η) and initial rate (v0) are those based on the TFO- anion. The 24h yield (24h-η) reached 64.9% in [Bmim][TFO] and 70.9% in [Bmpyrr][TFO] by transesterification while it reached 29.7% and 44.5% respectively in each IL by esterification. [Bmpyrr][TFO] based on the pyrrolidinium cation gave the best results although this cation has been rarely used for biocatalysis. This work has thus highlighted a cation that could be further studied in biocatalysis of glycosylated compounds. The study of the relationship between the structure of the ILs and the v0 and η for the biocatalysis of mannosyl myristate showed that the lipase effectiveness is influenced by the anions while the cations have an indirect influence on the interaction strength between Novozym® 435 and the anions. [less ▲]

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See detailEffect of New Synthetic PEGylated Ferulic Acids in Comparison to Ferulic Acid and Commercial Surfactants on the Properties of Wheat Flour Dough and Bread
Nicks, Francois ULg; Richel, Aurore ULg; Dubrowski, Thomas ULg et al

in Journal of the Science of Food and Agriculture (2013), 93(10), 2415-2420

BACKGROUND: Ferulic acid esterified with poly(ethylene glycol) with three different average molecular weights (200, 400 and 1000 g/mol) was studied in breadmaking. The effects of these antioxidants on the ... [more ▼]

BACKGROUND: Ferulic acid esterified with poly(ethylene glycol) with three different average molecular weights (200, 400 and 1000 g/mol) was studied in breadmaking. The effects of these antioxidants on the properties of wheat flour dough and bread were analyzed and compared with those obtained with ferulic acid and two commercial surfactants, diacetyl tartaric acid ester of mono- and diglycerides and sodium stearoyl lactylate. Farinographic and alveographic methods as well as weight, volume and bread firmness measurements were used for this purpose. <br /> <br />RESULTS: Such as ferulic acid, when the PEGylated derivatives were implemented in the dough (5000 ppm), it accelerated its breakdown and decreased its rheological properties. However, it allowed to avoid the important diminution of loaf volume observed when dough supplemented with ferulic acid was baked. That decrease in volume was related to the inhibition of the yeast (Saccharomyces cerevisae) by the unesterified ferulic acid. Moreover, two of the PEGylated ferulic acids even contributed to an increase of loaf volumes (5-6%) and demonstrated crumb softener properties. <br /> <br />CONCLUSION: The addition of ferulic acid in wheat flour dough caused the inhibition of the yeast, which resulted in decreased bread volume. That effect could be avoid by the esterification of ferulic acid with poly(ethylene glycol). [less ▲]

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See detailSynthesis and physico-chemical characterization of fatty esters
Sainvitu, Pauline ULg; Nott, Katherine ULg; Nicks, Francois ULg et al

Poster (2012, November 16)

Specific antioxidant molecules (e.g. phenolics) help to prevent oxidation reaction of the cell membrane. A fatty chain grafted on these compounds should enhance their capacity to interact with the ... [more ▼]

Specific antioxidant molecules (e.g. phenolics) help to prevent oxidation reaction of the cell membrane. A fatty chain grafted on these compounds should enhance their capacity to interact with the membrane lipids. In our study, three fatty esters comprising an aromatic part were synthesized. They differentiate the aromatic substituent and the number of carbons between the aromatic ring and the ester function. A structure-function relationships study was performed to identify the structural pattern affecting the interfacial properties and the membrane interaction properties. The behavior of their monolayer film at an air-water interface was studied. The interactions with membrane were assessed on living cells and were predicted by a computational approach. In the future, we will investigate the effect of the presence of a sugar unit on these molecules. [less ▲]

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See detailGreen synthesis and antioxidant activity of new PEGylated ferulic acids
Nicks, Francois ULg; Richel, Aurore ULg; Richard, Gaetan ULg et al

in Tetrahedron Letters (2012), 53(19), 2402-2405

PEGylation of ferulic acid is described through a green esterification process involving poly(ethylene glycol) (PEG) with three different average molecular weights (200, 400 and 1000 g/mol) as both ... [more ▼]

PEGylation of ferulic acid is described through a green esterification process involving poly(ethylene glycol) (PEG) with three different average molecular weights (200, 400 and 1000 g/mol) as both reactive and solvent. Esterification with PEG400 and PEG1000 leads to original compounds soluble in all proportions in water. These new compounds display an antioxidant activity similar to that of ferulic acid. [less ▲]

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See detailOlefin metathesis as key step in the synthesis of bioactive compounds: Challenges in the total synthesis of (-)-kendomycin
Bicchielli, Dario; Borguet, Yannick ULg; Delaude, Lionel ULg et al

in Current Organic Synthesis (2012), 9(3), 397-405

In this short review article, we highlight the application of the olefin metathesis reaction as a key step in the total synthesis of (-)-kendomycin, a macrocyclic polyketide ansamycin exhibiting ... [more ▼]

In this short review article, we highlight the application of the olefin metathesis reaction as a key step in the total synthesis of (-)-kendomycin, a macrocyclic polyketide ansamycin exhibiting pronounced activity as an endothelin receptor antagonist and antiosteoporotic agent, as well as important antibiotic potency against multiresistant bacteria and remarkable cytotoxicity versus a series of human tumour cell lines. By selecting this example from the recent literature, we hope to illustrate the great synthetic ability of olefin metathesis, while also revealing some problems encountered in the syntheses. © 2012 Bentham Science Publishers. [less ▲]

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See detailEfficient microwave-promoted synthesis of glucuronic and galacturonic acid derivatives using sulfuric acid impregnated on silica
Richel, Aurore ULg; Nicks, Francois ULg; Laurent, Pascal ULg et al

in Green Chemistry Letters & Reviews (2012), 5(2), 179-186

Monomode microwave-assisted syntheses of D-glucuronic and D-galacturonic acid derivatives are reported in the presence of a solid acid catalyst, consisting of sulfuric acid loaded onto silica. This ... [more ▼]

Monomode microwave-assisted syntheses of D-glucuronic and D-galacturonic acid derivatives are reported in the presence of a solid acid catalyst, consisting of sulfuric acid loaded onto silica. This approach affords a variety of surface-active monoglycosylated glucofuranosidurono-6,3-lactones and disubstituted galacturonic adducts in excellent yields in less than 10 min at 85 °C. This study illustrates the application of microwave heating mode, in combination with a cost-effective solid catalyst, as an efficient, selective and eco-friendly methodology in carbohydrate chemistry. [less ▲]

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See detailNovel, Highly Efficient and Selective Ruthenium Catalysts for the Synthesis of Vinyl Esters from Carboxylic Acids and Alkynes
Nicks, Francois ULg; Aznar, Rozario; Sainz, Daniel et al

in European Journal of Organic Chemistry (2009), 2009(29), 5020-5027

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See detailMicrowave-Assisted Ruthenium-Catalyzed Reactions
Nicks, Francois ULg; Borguet, Yannick ULg; Delfosse, Sebastien et al

in Australian Journal of Chemistry (2009), 62(3), 184-207

Since the first reports on the use of microwave irradiation to accelerate organic chemical transformations, a plethora of papers has been published in this field. In most examples, microwave heating has ... [more ▼]

Since the first reports on the use of microwave irradiation to accelerate organic chemical transformations, a plethora of papers has been published in this field. In most examples, microwave heating has been shown to dramatically reduce reaction times, increase product yields, and enhance product purity by reducing unwanted side reactions compared with conventional heating methods. The present contribution aims at illustrating the advantages of this technology in homogeneous catalysis by ruthenium complexes and, when data are available, at comparing microwave-heated and conventionally heated experiments. Selected examples refer to olefin metathesis, isomerization reactions, 1,3-dipolar cycloadditions, atom transfer radical reactions, transfer hydrogenation reactions, and H/D exchange reactions. [less ▲]

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See detailRuthenium-arene complexes bearing imidazol(in)ium-2-dithiocarboxylate ligands: Evaluation of their catalytic activity in the synthesis of enol esters
Willem, Quentin ULg; Nicks, Francois ULg; Sauvage, Xavier et al

in Journal of Organometallic Chemistry (2009), 694(25), 4049-4055

The catalytic activity of four ruthenium imidazol(in)ium-2-dithiocarboxylates was evaluated for the synthesis of vinyl esters through addition of 4-acetoxybenzoic acid to 1-hexyne, and compared to those ... [more ▼]

The catalytic activity of four ruthenium imidazol(in)ium-2-dithiocarboxylates was evaluated for the synthesis of vinyl esters through addition of 4-acetoxybenzoic acid to 1-hexyne, and compared to those of the parent ruthenium-N-heterocyclic carbene complexes and [RuCl2(p-cymene)(PPh3)] (a standard catalyst). It turned out that ruthenium imidazol(in)ium-2-dithiocarboxylates were poorly active and selective. Quantitative yields, indeed, were obtained only after extended reaction times. However, the catalytic activity could be improved significantly under microwave heating or conventional heating in a sealed tube at 160 degrees C, driving the reaction to completion in less than 4 h of reaction. [less ▲]

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See detailMicrowave-Assisted Synthesis of Vinyl Esters through Ruthenium-Catalyzed Addition of Carboxylic Acids to Alkynes
Nicks, Francois ULg; Libert, Lionel ULg; Delaude, Lionel ULg et al

in Australian Journal of Chemistry (2009), 62(3), 227-231

A rapid and efficient method is described for the selective synthesis of enol esters via the microwave-accelerated addition of carboxylic acids to terminal alkynes. The method employs the readily ... [more ▼]

A rapid and efficient method is described for the selective synthesis of enol esters via the microwave-accelerated addition of carboxylic acids to terminal alkynes. The method employs the readily available [RuCl2(p-cymene)(PPh3)] complex as catalyst without the need of bases, and reactions are complete in 20 min. [less ▲]

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See detailMicrowave-assisted synthesis of vinyl esters through ruthenium-catalyzed addition of carboxylic acids to alkynes
Nicks, Francois ULg; Libert, Lionel ULg; Delaude, Lionel ULg et al

in Polymer Preprints (2008), 49(2), 944-945

1-Hexen-2-yl 4-acetoxybenzoate was regioselectively prepd. via microwave-assisted ruthenium-catalyzed addn. of 4-acetoxybenzoic acid to 1-hexyne. Species of catalysts, reaction time and temp. play roles ... [more ▼]

1-Hexen-2-yl 4-acetoxybenzoate was regioselectively prepd. via microwave-assisted ruthenium-catalyzed addn. of 4-acetoxybenzoic acid to 1-hexyne. Species of catalysts, reaction time and temp. play roles in the reaction respect to yields and selectivity, therefore were examd. Microwave effect was obsd. and preferred to the generation of the Markovnikov-type product compared to traditional heating. [less ▲]

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