bluuebunny/crossref_metadata_2025_split huggingface dataset:
Condensation des Organomagnésiens sur les Chlorures D'Acide Dans le Tetrahydrofuranne a Basse Température
Authors: Dubois Jacques‐Emile , Lion Claude , Arouisse Abdelmajid 
Published: September 2010

AbstractLa condensation des organomagnésiens sur les chlorures d'acide substitués dans le THF à basse température permet la synthèse de cétones difficiles à obtenir par d'autres méthodes, en évitant la réaction parasite observée lors de la catalyse de cette réaction par CuCl dans l'éther. Appliquée à des chlorures d'acide et des organomagnésiens insaturés, la méthode permet également l'accès satisfaisant à des cétones éthyléniques comme l'Artémisia cétone.
Isolation of Stilbene Derivatives in the Bromination of 1,2‐Diaryl‐Ethylamides
Authors: Domínguez E. , Lata E. , Iriondo C. , Villa M. J. 
Published: September 2010

AbstractThe bromination reaction of the 1,2‐diaryl‐ethylamides (la‐d) afforded the expected bronoamides, together with two stilbene derivatives as by‐products: the (E)‐1‐(2‐bromo‐4,5‐dimethoxyphenyl)‐2‐(3,4‐dimethoxyphenyl)‐ethylene (3) and the (E)‐1,2‐bis(2‐bromo‐4,5‐dimethoxyphenyl)ethylene (4).
Hydrotreatment of Petroleum Residua Using Oceanic Manganese Nodules in a Trickle Bed Reactor
Authors: Dodet Claude , Noville Francis , Crine Michel , Marchot Pierre , Pirard Jean‐Paul 
Published: September 2010

AbstractOceanic polymetallic nodules could be used as a catalyst and an absorbent for hydrotreatment of petroleum residua in a trickle bed reactor because of their particular composition and porous texture. A kinetic study of this reaction has been undertaken in a micro‐pilot unit using operating conditions similar to those encountered in industrial reactors. Sulphur content, distillation characteristics and viscosity of the outlet liquid product were investigated. The effect of the main operating parameters (pressure, temperature and mass flow rates) has been determined.
A Thermostated Diafiltration Mini‐Apparatus For the Determination of Binding Parameters of Low Molecular Weight Ligands With Macromolecules
Authors: Claeyssens M. , van Tilbeurgh H. , De Bruyne C. K. 
Published: September 2010

AbstractA thermostated diafiltration apparatus (1–2 ml) is described. A more rigorous control of cell‐volume and temperature during equilibrium binding experiments by forced‐flow ultrafiltration is obtained. Because the apparatus induces two reservoirs with appropriate valves, leakage of macromolecular receptor at the start of the binding experiment, which is frequently a problem with commercial ultrafilters, can be controlled. The apparatus is first operated in the dialysis mode and the binding experiment is started by switching to the ligand containing reservoir. The construction of the filtrate‐collecting system overcomes the problem of variable void‐volume a and allows the apparatus to be used in other equilibrium dialysis modes.
On the Amidation of 17‐Deacetyl‐Vinblastine With the Ethylesters of Some Aminoacids
Authors: Bhushana Rao K. S. P. , Collard M. P. , Trouet A. , De Bruyn A. , Verzele M. , Noiret A. , Dejonghe J. P. , Hannart J. 
Published: September 2010

AbstractWe describe the synthesis of amides between 17‐deacetylvinblastine (1) and the ether esters of valine (2), leucine (3), isoleucine (4), tryptophane (5) and valine‐tryptophane (6).
A Preliminary Study About the Production by the Pultrusion Technique of a Fiber Reinforced Plastic (Frp) Tension Member For Use In Dielectric Composite Optical Fibre Communication Cable
Authors: Kiekens P. 
Published: September 2010

AbstractThe replacement of traditional coaxial copper cables for telecommunication networks by optical fibre cables requires the introduction of tension members to strengthen the cable. The production of these tension or strength members by pultrusion is discussed. The choice of reinforcing fibre and protecting matrix resin for the composite tension member is also treated. An optimal combination of these raw materials will lead to a pultruded strength member with outstanding properties for use in optical fibre cable.
Revisited Conformational Aspects of Pro and Hyp Pyrrolidine Rings In Bicyclic Peptide Systems
Authors: Sleeckx J. J. M. , Anteunis M. J. O. 
Published: September 2010

AbstractPyrrolidine ring conformational aspects in some bicyclic Pro and Hyp derivatives (DKP and Hydantoin) are analyzed from 1H nmr data using a generalised Karplus equation as developed by Haasnoot e.a. (3, 4). Previously published data are corroborated, but those for c/Pro, Hyp/ and c/Pro‐β‐Pro/ have been refined and re‐interpreted.
Stéréochimie De L'Électroréduction De Bromocyclopropanes. IV. Nouvel Exemple De L'Influence De La Composition De L'Électrolyte Sur La Stéréosélectivité De La Réaction
Authors: Hazard R. , Jaouannet S. , Tallec A. 
Published: September 2010

AbstractThe stereochemistry of the electroreduction of the two geometrical isomers of methyl 1‐bromocyclopropane 1,2‐dicarboxylate has been investigated:‐ for the trans isomer, electrolysis carried out in the presence of NH4+ ions give rise to a 90% retention ratio while 90% of inversion is attained when Bu4N+ cations are present.‐ preferential inversion of configuration always occurs for the reduction of the cis isomer and stereospecificity (i.e. 100% inversion) is achieved in the presence of Bu4N+ cations.These results are compared with those observed in the study of electroreduction of cis methyl 1‐bromo 2‐methoxymethyl cyclopropane 1,2‐dicarboxylate.
Molecular Structure Analysis of Minaprine Analogs: 3‐Morpholinoethylthio‐4‐Methyl‐6‐Phenyl‐Pyridazine, C17H21N3OS
Authors: van Der Brempt C. , Evrard G. , Durant F. 
Published: September 2010

AbstractMr=315.1, triclinic, P, a=11.162(3), b=10.793(3), c=9.142(4) A, α=103.05 (1), β=98.72(1), γ=126.42(1)º, V=804.0 λ3, Z=2, Dx=1.30 g.cm−3, Cu K+, λ=1.54178 λ, μ=17.18 cm−1, F(0,0,0)=336, T=293 K, final Rw=0.038 for 2559 observed [I 2.5σ(I)] reflections. The sulfur atom is sp2 hybridized and participates to the electronic delocalisation in the pyridazinic ring.
Spectres Rmn‐1H Et −13C Des Acides Mercapto‐2 Pyridinecarboxylique‐4, Mercapto‐4 Pyridinecarboxylique‐2 Et De Leurs Dérivés Méthyles Correspondants
Authors: Gelbcke M. , Grimée R. , Lejeune R. , Thunus L. 
Published: September 2010

AbstractProton and carbon‐13 chemical shifts and coupling constants of 2‐mercapto‐4‐pyridinecarboxylic acid, 4‐mercapto‐2‐pyridinecarboxylic acid and their seven respective methylated derivatives are reported. Substituent effects are discussed.
Carbon Monoxide Hydrogenation on the Reduced Nickel‐Titanium Crystal System
Authors: Malinowski M. , Makowski R. , Muranyi R. 
Published: September 2010

AbstractThe catalytic Ni‐Ti system was studied in the Fischer‐Tropsch reaction in a flow microreactor system under normal pressure. Nickel‐titanium was used as a crystal system reduced in a flow of hydrogen. No support was used. The influence of the titanium on the yield of higher hydrocarbons was observed
Rearrangement of 2‐Acyl‐2‐Chloro‐1, 3‐Cyclohexanediones into 2‐Acylresorcinols and 2‐Acyl‐4‐Chloro‐1, 3‐Cyclohexanediones
Authors: De Buyck L. , Seynaeve D. , De Kimpe N. , Verhé R. , Schamp N. 
Published: September 2010

Abstract2‐Acetylresorcinol was prepared in 80–881 yield from 2‐acetyl‐1, 3‐cyclohexanedione by 2‐chlorination (excess of NCS in boiling carbon tetrachloride or one equivalent of molecular chlorine in the cold solvent) followed by aromatization in a heated dry solution of hydrogen chloride in dimethylformamide. The scope of the method was extended to the preparation of 2‐propionyl‐and 2‐isobutyrylresorcinol (resp. 791 and 661 yield). Application of the method on 2‐acyl‐5, 5‐dimethyl‐1, 3‐cyclohexanediones (acyl=acetyl, propionyl, n‐butyryl, i‐butyryl) afforded the corresponding 2‐acyl‐4‐chlorodimedone derivatives in 40–771 yields
Polarographic Study of Schiff Bases Derived From 2‐Pyrrolecarboxaldehyde and 2‐Thiophenecarboxaldehyde
Authors: Capitán F. , Molina F. , Espinosa P. , Capitán‐Vallvey L. F. 
Published: September 2010

AbstractPolarographic behaviour of Schiff bases derived from 2‐pyrrolecarboxaldehyde and 2‐thiophenecarboxaldehyde has been investigated in 50%, dioxane‐water medium in pH range 4 to 10. The experimental conditions for the study were so chosen that no appreciable hydrolysis of the Schiff bases occurred during the recording of polarograms. Schiff bases gave two well separated monoelectronic waves in the pH range studied, which shifted to more negative potentials as the pH was increased. Dependence of diffusion current on concentration of depolarizer and height of mercury reservoir suggest that both the waves are diffusion controlled.On the basis of the polarographic and cyclic voltammetry data an overall electrode reaction is given.
Characterisation and Elimination of the Interfering Effects of the Foreign Species In Flame Atomic Absorption Spectrophotometric Analysis of Thallium
Authors: Mostafa M. A. , Kabil M. A. 
Published: September 2010

AbstractThe interfering effects of some foreign species in flame atomic absorption spectrophotometric analysis of thallium is discussed. The elimination of these interfering effects using either potassium cyanide or n‐butylamine is done. The mechanism of their releasing effect is illustrated. The inhibition release titration method has been used in studying the interfering effects.
Extraction‐Photometric Determination of Oxalate in Urine With Furohydroxamic Acid (Fha)
Authors: Martínez‐Vidal J. L. , González‐Pradas E. , Villafranca M. , Salinas F. 
Published: September 2010

AbstractFurohydroxamic acid reacts with V(V) and oxalate anion to give a mixed ligand complex of stoichiometry 2:1:1, that it is extracted in toluenic solution of Adogen 464. The ionic pair extracted follows the Beer law between 4 and 13 ppm of oxalate at 633 nm (ε=4,300 L mol−1 cm−1). The determination of oxalate in urine is achieved.
Solution Conformation of Cyclic Dipeptides of Pipecolic and Thiapipecolic Acid Combined With Glycine and Sarcosine
Authors: Reyniers FrançOise S. , Borremans Frans A. M. , Anteunis Marc J. O. 
Published: September 2010

AbstractFrom 1 H NMR parameters we demonstrate that the cyclic dipeptides derived from L‐pipecolic acid and L‐γ‐thiapipecolic acid with glycine or sarcosine are negatively buckled. The degree of folding of the diketopiperazine ring increases in the γ‐thia‐analog. The evaluation of the effect of changing the solvent from chloroform to methanol, and of N‐methylation of the Gly residue, on the buckle of the DKP ring is attempted.
Réaction De L'Indazole Avec Le Chlorure De Trityle: Identification Par Rmn Du Proton Des Isomères 1‐, 2‐Et 3‐Substitues
Authors: Claramunt Rosa Maria , Elguero José , Fruchier Alain 
Published: September 2010

AbstractThe first example of substitution on position 3 of indazole by an alkylating agent is described. It takes place, together with substitution in position 1 and 2, when indazole is allowed to react with trityl chloride. The three isomers were characterized by their proton nmr spectra at 360 MHz.
Synthesis of New Aziridime‐Carboxamide‐, Thioamide‐, Amidime‐Derivatives and Their Reaction With Phosgene
Authors: Lambert C. , Merényi R. , Caillaux B. , Viehe H. G. 
Published: September 2010

AbstractThe reactions of primary amines with α‐chloroacrylamide 2, thioamide 3 or amidinium salts 8 give the corresponding aziridines, which themselves are used for the synthesis of new heterocyclic systems when treated with phosgene.
Chemistry of 2‐Diphenylphosphoryl Ketene Thioacetals
Authors: Schaumann Ernst , Fittkau Stefan 
Published: September 2010

AbstractCarbanions of diphenylphosphane oxides add to carbon disulfide to give, after alkylation, the title compounds 4. In the reaction with the allylphosphane oxide 5, exclusive γ‐attack is observed to yield dienes 6B. An exploratory study of the reactivity of 4 shows that reduction to thioacetal 7 and hydrolysis to 5‐thiocarboxylates 10 are feasible. Deprotonation of phosphane oxides having a β‐sulfur substituent reveals a high tendency to thiolate elimination to give vinyl sulfides 9, resp. 15. However, reaction of thioester 10a with benzaldehyde indicates that the compounds can be used in Wittig‐Horner olefinations. Ketene thioacetal 4e gives a 1,3 methylthio shift on treatment with acid.
Macromolecular Prodrugs of Metronidazole. 1. Esterification of Hydroxyl Containing Polymers With Metronidazole Monosuccinate
Authors: Vermeersch Joan , Vandoorne Filip , Permentier Dirk , Schacht Etienne 
Published: September 2010

AbstractMetronidazole was converted into the corresponding monosuccinate ester by treatment with succinic anhydride in almost quantitative yield and under mild reaction conditions. The monosuccinate derivative was subsequently coupled onto dextran, inulin and poly‐[N‐(2‐hydroxyethyl)aspartamide].
Valence Electron Density, Deformation Potential and Reactivity of α‐Al2O3 Studied By X‐Ray Diffraction
Authors: Lenstra A. T. H. , De Wolf M. , Vanhouteghem F. 
Published: September 2010

AbstractThe structure of α‐Al2o3 was investigated using X‐ray single crystal data. The model of the structure is shown to be stable in θ‐biased refinements. Corrections on the observed intensities adjusting negative function values for Iobs and removing the impact of thermal diffuse scattering have no effect on positional parameters and only a minor effect on thermal parameters. Transfer of electrons between valence shells proved an important characteristic of the structure, but the coupling of thermal parameter values to the choice of scattering functions prevented the determination of net atomic charges. The electronic potential due to outer‐shell electrons (dynamic deformation potential) indicates the preferred sites for attack by positive and negative ions.
Extraction and Spectrophotometric Determination of Ti(IV) Using 2‐Pyrilideniminobenzohydroxamic Acid As Chelating Agent
Authors: Salinas F. , Jiménez‐Arrabal M. , Merás I. Durán 
Published: September 2010

AbstractThe reaction of Ti(IV) with 2‐pyrilideniminobenzohydroxamic acid (2‐PIBHA) was studied in aqueous medium and by using an extraction in isoamyl alcohol. The stoichiometries of the complexes formed are 1:1 and 1:3 (Ti(IV):reagent) in both cases.The extraction and spectrophotometric determination of titanium with 2‐PIBHA can be performed in a concentration range from 0.1 to 1.4 μg/ml of Ti(IV). The apparent molar absorptivity in isoamyl alcohol is 39600 1.mol−1.cm−1 at 375 nm. The relative error of the method is ± 0.64% for 25 μg of Ti(IV) in the aqueous phase (50 ml) and the extraction constant is 1.45×1013.
2‐Hydroxy‐1‐Naphthaldehyde Guanylhydrazone as an Analytical Reagent Extractive‐Spectrophotometric Determination of Iron
Authors: Salinas F. , Berzas J. J. , Eapinosa Mansilla A. 
Published: September 2010

AbstractThe synthesis and the analytical properties of 2‐hydroxy‐1‐naphthaldehyde guanylhydrazone are described for the first time. New methods for estimation of iron in homogeneus medium and by extraction in isoamyl alcohol have been proposed.The extractive‐spectrophotometric determination of iron with NAG can be performed between 6.25–150 μg of iron; the molar absortivity is 5.20×103 liters mole−1.cm−1 at 575 nm, the relative error is ± 1.30% and the extraction constant is 2.17×1011 The proposed method was applied to the determination of iron in a Portland cement and in a high‐purity magnesite.
Computarized Searching Program to Identify the Primary Structure of Peptides and Proteins by Using Chemical Shifts C‐13 Data. Amino Acids
Authors: Hashem K. M. E. , A‐E‐A. Ali F. 
Published: September 2010

AbstractA computer program to identify the primary structure of “unknown” peptides and proteins is described, based upon the Chemical shifts of C‐13 for 28 common amino acids. The spectra have been measured by high resolution nmr spectroscopy to be used as reference data. To facilitate the investigation procedure, the characteristic Chemical shift (s) are selected. The operation of the program and its performance in investigation of unknown spectra of three hypothetical peptides are fully illustrated after complete hydrolysis in 6N HCl. Correlation between the obtainable results proved the stability of a hydrolysis intermediate by‐product kinetically affected by the polar and steric factors of the main function group in the media.
Approche Expérimentale de la Relaxation de L'Énergie Cédée a un Solide Moléculaire par un Rayonnement Ionisant
Authors: Tilquin B. 
Published: September 2010

AbstractThe purpose of this work is to further clarify the subtle matrix effect on the energy transfer in alkane solid radiolysis. In this autoreview, previous results are interpreted in terms of exciton migration inhibited at the solid‐solid interfaces.
Étude de la Réactivité D'Ylideneoxazoline‐5‐Ones vis‐à‐Vis de Composés Enaminocarbonyles
Authors: Maquestiau A. , Vanden Eynde J.‐J. , Papleux P. 
Published: September 2010

AbstractReactions between 4‐ylideneoxazolin‐5‐ones and enaminocarbonyl compounds do not lead to 4,7‐dihydrooxazolopyridines. These reactions yield, by cleavage of the five‐membered ring, monocyclic derivatives whose structures are elucidated.Thus, starting from 4‐arylideneoxazolin‐5‐ones, mixtures of cis and trans dihydro‐α‐pyridones are formed but, in most cases, only the cis isomers can be isolated.Starting from 2‐phenyl‐4‐ethoxymethyleneoxazolin‐5‐one, reactions proceed, in addition, by loss of ethanol and α‐pyridones are obtained.
Application des Règles de Sélection MCD au Spectre du Cristal Dope: YAl3(BO3)4/EU3+
Authors: Görller‐Walrand C. , Vandevelde P. 
Published: September 2010

AbstractThe selection rules previously developed for the magnetic dipole allowed transition 5D1 ← 7Fo and the induced electric dipole allowed transition 5D2 ← 7Fo in the MCD spectrum of Eu3+ are applied and discussed with respect to the spectrum of the huntite crystal: YAl3(BO3)4/Eu3+.The 5D1 ← 7Fo transition appears as a positive A1 signal whereas to the 5D2 ← 7Fo transition correspond two A1‐terms with opposite sign. These features confirm the hypothesis that the magnetic dipole allowed transition is symmetry independent while the induced electric dipole transition is closely related by its sign to the site symmetry of the Eu3+ ion, in this case D3.
Friedel‐Crafts Synthesis of Benzophenone with Little Lewis Acid Catalyst. Factorial Design and Mechanism
Authors: Scuotto Jean‐François , Mathieu Didier , Gallo Roger , Phan‐Tan‐Luu Roger , Metzger Jacques , Desbois Michel 
Published: September 2010

AbstractA series of benzene derivatives C6H5R with R ranging from the two extremes of the σ+ scale of H.C. Brown has been acylated with little FeCl3 catalyst at reflux temperature. Under these conditions the reaction is limited to activated substrates: with benzene and deactivated aromatics the yield is below 10%. A fractional factorial design is carried out with 5 parameters: temperature, % catalyst, time, ratio aromatic/acylation reagent and nature of catalyst in the case of acylation of benzene by benzoyl chloride with a Lewis acid catalyst (AlCl3 or FeCl3). The multivariate analysis shows that the important factors are: temperature, nature and ratio of catalysts; and also that the interaction % of catalyst‐nature of catalyst and temperature‐nature of catalyst are determinant. Acylation of benzene (and deactivated aromatics) with little Lewis acid catalyst will give acceptable yields if both a moderately active catalyst (FeCl3, ZnCl2) and a high temperature of reaction are used.
Rélations et Similarité Structurales: Régularité et Interactions Modèle Topologique Pulso a Environnement Variable
Authors: Dubois J. E. , Doucet J. P. , Panaye A. 
Published: September 2010

AbstractLFER correlations are justified by similarity functions developed in Taylor series. In the same formalism of Palm‐Leffler‐Wold, we present here an equation expressing similarity relations based on information extracted from a model with a variable environment (E) for a transition sO + s. This model is implemented in the PULSO topological method. Thanks to the procedure used, and called “nE/2s”, we can decompose the action of a substituent s in two terms related to the action of s on a reference environment EO and to its interaction on (E1 ‐ EO). This model complements the usual one which has a constant environment E. The LFER relations, procedure (2E/ns) used especially for monosubstitutions, source of action parameters, is hardly efficient for Multiple Substitution Effect studies (MSE) because of the difficulties involved in evaluating interactions. Both models can be used either within the framework of a population (internal treatment) or with external references. The new model, alone or in association with the first, is used to identify the nature of the interactions to be associated with Taylor derivatives.
Barrières de Rotation Adjacentes aux Doubles Liaisons Étude Structurale Théorique D'Acides Carboxyliques, Oléfines et Amides, Relaxation Tensionnelle et Déformations Valencielles des Composés Contraints
Authors: Cossé‐Barbi A. , Massat A. , Dubois J. E. 
Published: September 2010

AbstractConformations associated with alkyl groups adjacent to a double bond are studied on five series of aldehyde, ketone, carboxylic, amide and olefine compounds. The data used, spectroscopic or theoretical, are based on 14 compounds R(C‐X)Y with Y‐H,OH,Me,N (Me)2 and X‐O or CH2. The number, the relative abundance of conformers and the heigth of the rotation barriers obtained by the PCILO method are discussed for two series of compounds with neopentyl chains BuCH2(C=X)Y and triptyl groups tBu(Me)2C(C‐X)Y.In each case, the eclipsed double bond form competes with one or two skew conformers.For simple flexible compounds, the conformational motion is determined primarily by rotation relaxation. But for compounds with high structural constraints, the relaxation mechanism implies variations in the bond angles. The conformational flexibility is greatly increased and linked to a marked attenuation of the rotation barriers. The valency relaxation of tensions is estimated at between 20 and 30 kilocalories. When the constraints are important, they are associated with the existence of strong interactions of the two alkyl groups situated in δ position with regard to each other.