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See detailMechanistic Insight into the Staudinger Reaction Catalyzed by N-Heterocyclic Carbenes
Hans, Morgan ULg; Wouters, J.; Demonceau, Albert ULg et al

in Chemistry : A European Journal (2013), 19(19), 9668-9676

Four zwitterions were prepared by treating 1,3-dimesitylimidazolin-2-ylidene (SIMes) or 1,3-dimesitylimidazol-2-ylidene (IMes) with either N-tosyl benzaldimine or diphenylketene. They were isolated in ... [more ▼]

Four zwitterions were prepared by treating 1,3-dimesitylimidazolin-2-ylidene (SIMes) or 1,3-dimesitylimidazol-2-ylidene (IMes) with either N-tosyl benzaldimine or diphenylketene. They were isolated in high yields and characterized by IR and NMR spectroscopy. The molecular structures of three of them were determined by using X-ray crystallography and their thermal stability was monitored by using thermogravimetric analysis. The imidazol(in)ium-2-amides were rather labile white solids that did not show any tendency to tautomerize into the corresponding 1,2,2-triaminoethene derivatives. They displayed a mediocre catalytic activity in the Staudinger reaction of N-tosyl benzaldimine with diphenylketene. In contrast, the imidazol(in)ium-2-enolates were orange-red crystalline materials that remained stable over extended periods of time. Despite their greater stability, these zwitterions turned out to be efficient promoters for the model cycloaddition under scrutiny. As a matter of fact, their catalytic activity matched those recorded with the free carbenes. Altogether, these results provide strong experimental insight into the mechanism of the Staudinger reaction catalyzed by N-heterocyclic carbenes. They also highlight the superior catalytic activity of the imidazole-based carbene IMes compared with its saturated analogue SIMes in the reaction under consideration. [less ▲]

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See detailPhysicochemical characterization of fat blends related to margarine formulation
Danthine, Sabine ULg; Fernando Munoz, J; Cavillot, V et al

Poster (2009)

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See detailPHYSICOCHEMICAL PROPERTIES OF EUROPEAN BAKERY MARGARINES WITH AND WITHOUT TRANS FATTY ACIDS
Cavillot, V.; Pierart, Céline ULg; De Meerendre, M Kervyn et al

in Journal of Food Lipids (2009), 16(3), 273-286

Physicochemical properties of commercially available European bakery margarines (cream margarines, cake margarines [CM] and puff pastry margarines [PPM]) containing and devoid of trans fatty acids (TFAs ... [more ▼]

Physicochemical properties of commercially available European bakery margarines (cream margarines, cake margarines [CM] and puff pastry margarines [PPM]) containing and devoid of trans fatty acids (TFAs) were investigated. Studied physical properties were the solid fat content (SFC), dropping points (DPs), polymorphism, texture (hardness), plasticity and the melting profile by differential scanning calorimetry. Experimental results confirm that physical properties of the margarines corresponded with their application area. For example, SFC and DPs of PPM were higher than cream margarines and CM; they were also harder at 15C. Moreover, all the investigated physical properties were affected by the suppression of TFA in bakery margarines. PRACTICAL APPLICATIONS This study has shown that margarines present different physical properties with respect to their purposed application but also highlight changes that appear due to the absence of trans-fatty acids in the formulations. These changes can really affect the bakery abilities and will, finally, influence the quality of the bakery products. [less ▲]

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See detailEffect of the content of partially hydrogenated oils on the physical and structural properties of bakery margarines
Cavillot, V; Danthine, Sabine ULg; Kervyn de meerendré, M. et al

Poster (2008)

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See detail(+/-)-2-Benzoyl-8-ethyl-1,2-dihydro-isoquinoline-1-carbonitrile: an original Reissert compound
Graulich, Amaury ULg; Norberg, B.; Liégeois, Jean-François ULg et al

in Acta Crystallographica Section E-Structure Reports Online (2007), 63(Part 7), 3161-3073

The title compound, C19H16N2O, is a Reissert compound. The heterocyclic fragment of the molecule exhibits a 1,3-diplanar conformation. The phenyl ring is connected to the isoquinoline ring system via an ... [more ▼]

The title compound, C19H16N2O, is a Reissert compound. The heterocyclic fragment of the molecule exhibits a 1,3-diplanar conformation. The phenyl ring is connected to the isoquinoline ring system via an amide bond that adopts an anti conformation with respect to the adjacent C-N bond in the adjacent heterocyclic ring. Intra-and intermolecular C-H center dot center dot center dot O hydrogen bonds are present in the crystal structure. [less ▲]

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See detailComposition of degumming residues from oil physical refining : valorization for food application
Pierart, Céline ULg; Cavillot, Véronique; Kervyn de Meerendré, M. et al

Poster (2007)

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See detailCharacterization of puff pastry margarines with and without TFA
Cavillot, V; Kervyn de Meerendré, M; Pierart, Céline ULg et al

Poster (2007)

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See detailCaking phenomena and physical parameters of amorphous inulin related to adsorption and desorption isotherms.
Ronkart, Sébastien; Paquot, Michel ULg; Fougnies et al

Poster (2006, March)

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See detailDetermination of physical changes of inulin related to sorption isotherms: An X-ray diffraction, modulated differential scanning calorimetry and environmental scanning electron microscopy study
Ronkart, Sébastien ULg; Blecker, Christophe ULg; Fougnies, C. et al

in Carbohydrate Polymers (2006), 63(2), 210-217

This paper gives a relationship between powdered inulin behaviour and physical parameters determination. Glass transition temperature (T,) and development of crystallinity were measured in relation to the ... [more ▼]

This paper gives a relationship between powdered inulin behaviour and physical parameters determination. Glass transition temperature (T,) and development of crystallinity were measured in relation to the water moisture of the polymer. These parameters were obtained by Modulated Differential Scanning Calorimetry (MDSC) and powder X-ray diffraction, respectively. In order to change the water content of the powder, adsorption and desorption isotherms (using different relative humidity storage conditions) were done and successfully fitted to the Guggenheim-Anderson-de Boer (GAB) model. Dependent on the relative humidity storage, a caking phenomenon occurred when glass transition temperature was under storage temperature. An Environmental Scanning Electron Microscopy (ESEM) study showed a structural change when water activity increased above 0.56 at 20 degrees C. A correlation between the increase of the crystallinity and the hardening of the powder was determined. ESEM permitted an observation of the development of some crystal structures among the amorphous system, confirmed by an increase of the diffraction peaks obtained by powder X-ray diffraction. These observations lead to an understanding of the physical characteristics of inulin related to the water moisture. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

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See detailCyproterone and a comparison with its acetate ester
de Ruyck, J.; de Hassonville, S. H.; Liégeois, Jean-François ULg et al

in Acta Crystallographica Section E-Structure Reports Online (2005), 61(Part 11), 3576-3578

The crystal structure of cyproterone (systematic name: 6-chloro-1,2-dihydro-17-hydroxy-30H-cyclopropa[a]pregna-1,4,6- triene-3,20-dione), C22H27ClO3, is compared with cyproterone acetate, a potent anti ... [more ▼]

The crystal structure of cyproterone (systematic name: 6-chloro-1,2-dihydro-17-hydroxy-30H-cyclopropa[a]pregna-1,4,6- triene-3,20-dione), C22H27ClO3, is compared with cyproterone acetate, a potent anti-androgen steroid. The two compounds adopt a similar conformation, except for the cyclopropyl ring attached to the cyclohexenone ring (ring A). Cyproterone further adopts a crystal packing distinct from that of the acetate form. These differences result from hydrogen bonding between the free hydroxy group and the carbonyl group of ring A. [less ▲]

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See detail3,6-Disubstitued coumarins as mechanism-based inhibitors of thrombin and factor Xa
Frederick, R.; Robert, S.; Charlier, C. et al

in Journal of Medicinal Chemistry (2005), 48

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See detailPhysicochemical Characteristics of some ternary Fat Blends
Danthine, Sabine ULg; gibon, véronique; norberg, B. et al

Poster (2004, November)

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See detailComparison between co-crystallisation properties of POP and OPP
Danthine, Sabine ULg; tirtiaux, a; wouters, j et al

Poster (2004)

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See detailCrystal structure of Enterobacter cloacae 908R class C beta-lactamase bound to iodo-acetamido-phenyl boronic acid, a transition-state analogue
Wouters, J.; Fonze, E.; Vermeire, M. et al

in Cellular and Molecular Life Sciences (2003), 60(8), 1764-1773

The structures of the, class C beta-lactamase from Enterobacter cloacae 908R alone and in complex with a baronic acid transition-state analogue were determined by X-ray crystallography at 2.1 and 2.3 ... [more ▼]

The structures of the, class C beta-lactamase from Enterobacter cloacae 908R alone and in complex with a baronic acid transition-state analogue were determined by X-ray crystallography at 2.1 and 2.3 Angstrom, respectively. The structure of the enzyme resembles those of other class C beta-lactamases. The structure of the. complex with the transition-state analogue, iodo-acetamido-phenyl boronic acid, shows that the inhibitor is covalently, bound to the active-site serine (Ser64). Binding of the inhibitor within the active site is compared with previously determined structures of complexes with other class C enzymes. The structure of the boronic acid adduct indicates ways to improve the affinity of this class of inhibitors. This structure of 908R class C beta-lactamase in complex with a transitionstate analogue provides further insights into the mechanism of action of these hydrolases. [less ▲]

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See detailNew 3-deoxyanthocyanidins from leaves of Arrabidaea chica
Devia, B.; Llabres, Gabriel ULg; Wouters, J. et al

in Phytochemical Analysis [=PCA] (2002), 13(2, Mar-Apr), 114-120

Two new 3-deoxyanthocyanidins, 6,7,3',4'-tetrahydroxy-5-methoxyflavylium and 6,7,4'-trihydroxy-5-methoxyflavylium, and the pigment carajurin, which has been previously identified, were isolated from dried ... [more ▼]

Two new 3-deoxyanthocyanidins, 6,7,3',4'-tetrahydroxy-5-methoxyflavylium and 6,7,4'-trihydroxy-5-methoxyflavylium, and the pigment carajurin, which has been previously identified, were isolated from dried leaves of Arrabidaea chica, a creeper native to the American tropics. The structures of the components were elucidated by H-1- and C-13-NMR spectroscopy and HPLC-MS, including X-ray crystallographic analysis for carajurin. Copyright (C) 2002 John Wiley Sons, Ltd. [less ▲]

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See detailStructural approach of the mechanism of inhibition of -chymotrypsin by coumarins
Wouters, J.; Huygens, M.; Pochet, L. et al

in Bioorganic & Medicinal Chemistry Letters (2002), 12

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See detailCrystallographic analysis of family 11 endo-beta-1,4-xylanase Xyl1 from Streptomyces sp. S38.
Wouters, J.; Georis, J.; Engher, D. et al

in Acta Crystallographica Section D-Biological Crystallography (2001), 57(Pt 12), 1813-9

Family 11 endo-beta-1,4-xylanases degrade xylan, the main constituent of plant hemicelluloses, and have many potential uses in biotechnology. The structure of Xyl1, a family 11 endo-xylanase from ... [more ▼]

Family 11 endo-beta-1,4-xylanases degrade xylan, the main constituent of plant hemicelluloses, and have many potential uses in biotechnology. The structure of Xyl1, a family 11 endo-xylanase from Streptomyces sp. S38, has been solved. The protein crystallized from ammonium sulfate in the trigonal space group P321, with unit-cell parameters a = b = 71.49, c = 130.30 A, gamma = 120.0 degrees. The structure was solved at 2.0 A by X-ray crystallography using the molecular-replacement method and refined to a final R factor of 18.5% (R(free) = 26.9%). Xyl1 has the overall fold characteristic of family 11 xylanases, with two highly twisted beta-sheets defining a long cleft containing the two catalytic residues Glu87 and Glu177. [less ▲]

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See detailExpression, purification, crystallization and preliminary X-ray analysis of the native class C beta-lactamase from Enterobacter cloacae 908R and two mutants.
Wouters, J.; Charlier, Paulette ULg; Monnaie, D. et al

in Acta Crystallographica Section D-Biological Crystallography (2001), 57(Pt 1), 162-4

Crystals have been obtained of the Enterobacter cloacae 908R beta-lactamase and two point mutants by the vapour-diffusion method using similar conditions [pH 9.0, polyethylene glycol (M(r) = 6000) as ... [more ▼]

Crystals have been obtained of the Enterobacter cloacae 908R beta-lactamase and two point mutants by the vapour-diffusion method using similar conditions [pH 9.0, polyethylene glycol (M(r) = 6000) as precipitant]. The three crystal forms belong to the orthorhombic space group P2(1)2(1)2, with roughly the same unit-cell parameters; i.e. for the wild-type crystals a = 46.46, b = 82.96, c = 95.31 A. In the best cases, the crystals diffract to about 2.1 A resolution on a rotating-anode X-ray source at room temperature. Co-crystallization experiments of poor substrates with the wild-type protein and the active-site serine mutant (S64C) are planned and should lead to a better understanding of the catalytic mechanism of class C beta-lactamases. [less ▲]

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