bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure cristalline et moléculaire de la cyano‐5 triméthyl‐4,4,6 nitrométhylène‐2 oxo‐3 tetrahydro‐1,2,3,4 pyridine et de l'(acétoxy‐1 nitro‐2 vinyl)‐5 dicyano‐3,5 diméthyl‐4,4 pyrazoline‐2‐(z)
Authors: Declercq J. P. , Germain G. , van Meerssche M. , Hajek M. , Kurfürst A. 
Published: September 2010

AbstractThe crystal structure of 5‐cyano‐4,4,6‐trimethyl‐2‐nitromethylene‐3‐oxo‐1,2,3,4‐tetrahydropyridine (compound I) and (Z)‐5‐(1‐acetoxy‐2‐nitroviny1)‐3,5‐dicyano‐4,4‐dimethyl‐2‐pyrazoline (compound II) has been determined by X‐ray diffraction analysis. The direct solution of the structures were performed by the MULTAN 80 method and refined by least squares to R‐value of 0.044 (I) and 0.069 (II) respectively, for 672 (I) and 958 (II) independent observed reflections.The crystals of (1) are monoclinic, space group P21, with a=6.718(5), b=6.464(5), c=15.713(10)Å, β=128.23(5)° and Z=2. The crystals of (II) are orthorhombic, space group Pbca, with a=12.040(6), b=12.808(6), c=16.821(9)Å and Z=8.The obtained distances and angles of the pyrazoline ring are in good agreement with the literature data.
Solution Conformation of Salinomycin and 4‐Methylsalinomycin (Narasin) from 1H NMR Studies. Carboxylic Acid Ionophores with Restricted Flexibility
Authors: Anteunis Marc J. O. , Rodios Nestor A. 
Published: September 2010

AbstractThe solution conformations of salinomycin and narasin, obtained from 1H nmr spectroscopy, reveal that these ionophores, as most other polyethers, possess a constitution that is predestinated for catching an ion and carry it through the lipid bilayer. A few specific bonds only act as hinges. They are designed to act so by the spatial and constitutional distribution of the aliphatic substituents along the ionophoric frame work. This is further exemplified by a comparison with the solid‐state data7 of salinomycin p‐iodophenacyl ester.
Influence of Electronic Delocalization on the Dipole Moment of Enamino Ketones
Authors: Vanbrabant‐Govaerts H. , Huyskens P. 
Published: September 2010

AbstractThe dipole moments of 3‐dimethylamino‐1‐phenyl‐2‐propene‐1‐one and of β‐dimethylaminopropiophenone have been determined in benzene at 298.16 K. They are respectively 4.64±0.02 Debye and 2.88±0.02 Debye. The presence of the CC double bond in the enamino ketones allows an important electronic delocalization from the nitrogen atom towards the oxygen atom in the group N‐CHCH‐CO. This does not occur in the saturated group =N‐CH2‐CH2‐CO, the moment of which results to a good approximation from the vector addition of the group moments at both sides of the CH2‐CH2 bond. In the enamino ketone the electronic delocalization brings about a mesomeric moment as large as 2.5 Debye, markedly larger than the mesomeric moment of dimethylacetamide. This can be ascribed to the larger distance between the nitrogen and oxygen nuclei in the enamino ketone.
Phase Transfer Catalysis in Heterocyclic Chemistry. (A Review)
Authors: Gallo Roger , Dou Henri J‐M , Hassanaly Parina 
Published: September 2010

Abstract
Introduction
Syntheses of heterocyclic compounds
Heterocycles as nucleophilic reagents
Heteroaromatic nucleophilic substitutions.
Additions and insertions on (via) heterocycles.
Heterocycles synthetic intermediates.
Heterocycles catalysts.
Miscellaneous.
Tervalent Lanthanon Derivatives of Monoprotic Tridentate Schiff Bases Containing Oxygen and Nitrogen Donor Atoms
Authors: Gupta C. P. , Sharma K. G. 
Published: September 2010

AbstractNine‐coordinated derivatives of the type [LnL3] and [LnL3], LnPr(III), Nd(III), Sm(III), Ho(III) and Er(III) and LHO‐(N‐α‐furfuralideneimino) ethane sulphonic acid (HFES) and L'HO‐(N‐α‐furfuralideneimino) benzene sulphonic acid (HFBS) have been synthesised by the reaction of lioand with Ln(NO3)3. These derivatives have been isolated in solid state and characterised on the basis of elemental analysis, conductance, magnetic and spectral datas.The room‐temperature magnetic moments of the tervalent lanthanon derivatives are characteristic of terpositive lanthanide ions. Electronic spectra of these derivatives have been analysed in the light of LSJ terms and give characteristic f‐f transitions. A nine‐coordinated polymeric structure is proposed for these derivatives in which the lanthanide atom is bonded through oxygen and nitrogen donor atoms of Schiff bases. Ligands (HFES and HFBS) are structurally similar and are expected to behave as monoprotic tridentates.
Décomposition thermique du N‐butoxy‐1 (t‐butylperoxy)‐1 éthane en solution dans le triisopropyl benzène
Authors: Maillard B. , Filliatre C. , Manigand C. , Villenave J. J. 
Published: September 2010

AbstractThe pyrolysis of 1‐n‐butoxy‐1‐(tert‐butylperoxy) ethane in triisopropylbenzene leads to the formation of methane, tert‐butyl alcohol, n‐butyl formate and n‐butyl acetate as previously described. To verify the hypotheses on the origin of the esters a kinetic analysis of this reaction has been performed by differential scanning microcalorimetry. If the unimolecular homolysis of the peroxide function can account for the formate ester, the formation of the acetate ester cannot be explained only by the induced decomposition of the peroxide by tert‐butoxy radicals. The alternative origin of the acetate ester is the disproportionation of the initial radicals in the solvent cage.
Étude comparative de la réactivité des acridanones, des aminoacridines et des thioacridanones vis‐à‐vis des agents d'alkylation dans les conditions de la catalyse par transfert de phase
Authors: Galy J.‐P. , Vincent E.‐J. , Galy A.‐M. , Barbe J. , Elguero J. 
Published: September 2010

AbstractThis paper describes the results obtained in the alkylation of thioacridanone under phase transfer catalysis conditions. Nine different alkylating agents have been used and in all the cases the thioether was the sole product obtained. Proton and carbon‐13 n.m.r. study of the different compounds has been carried out, giving a useful criteria to differentiate thoethers and thioacridanones. The HSAB principle has been used to discuss the relative amounts of 9‐and 10‐substituted isomers obtained from acridanones, aminoacridines and thioacridanones using different alkylating and acylating agents.
Étude du Comportement Chimique de Pyrano [2, 3‐c] Pyrazole‐3 (2h)‐Ones Vis‐à‐Vis des Bases Azotées. I. Réaction Avec les Amines Aromatiques
Authors: Maquestiau A. , van Haverbeke Y. , Vanden Eynde J.‐J. 
Published: September 2010

Abstract2‐phenyl‐4, 6‐dimethylpyrano [2, 3‐c] pyrazole‐3 (2H)‐one reacts with arylamines to form arylaminoethylidenepyrazolidin‐3, 5‐diones.The reaction pathway is highly dependent on the nature of the arylamine.
An Efficient Synthesis of the Enantiomers of Methadone‐D10
Authors: Gérardy B. M. , Poupaert J. , Dumont P. 
Published: September 2010

AbstractA reactions sequence is described to prepare the enantiomers of Methadone‐d10. The proposed scheme allows to synthesize racemic Methadone‐d10 with 14% overall yield, starting from benzene‐d6. (‐)‐Methadone‐d10 hydrochloride is assigned the (R)‐absolute configuration on the basis of its ORD curve.
Electron Transfer Between Hexacyanoferrate (III) and Thiosulphate‐a Kinetic and Mechanistic Study in Aqueous Alkaline Media
Authors: Panda Rama Krushna , And Gautam Neogi , Ramaswamy D. 
Published: September 2010

AbstractKinetics of oxidation of thiosulphate by hexacyanoferrate (III) in aqueous alkaline media follow a rate‐expression, «span» where Kh and k2 respectively represent the hydrolysis constant of thiosulphate and the self‐decomposition constant of acid thiosulphate ion; the Kh and k2 values have been respectively computed to be (1.09±0.1)x10−3 mol dm−3 and (6.13±0.4)x10−7 s−1 at 318 K and 0.32 mol dm−3 of ionic strength in alkaline medium. The mechanism is interpreted in terms of a spontaneous change of thiosulphate in a rate‐determining step, followed by a rapid reduction of hexacyanoferrate (III).
Ru(III) Chloride Catalysed Oxidation of Some Alcohols by Ditellurato Cuprate(III) in Alkaline Medium. A Kinetic Study
Authors: Reddy K. Bal , Sethuram B. , Rao T. Navaneeth 
Published: September 2010

AbstractThe kinetics of Ru(III) catalyzed oxidation of methanol, ethanol, n‐propanol, iso‐propanol, n‐butanol, benzyl alcohol, cyclopentanol, cyclohexanol and cycloheptanol by ditellurato cuprate(III) in alkaline medium was studied spectrophotometrically. The order in [cu(III)] is zero and that in [alcohol] and [Ru(III)] unity. The rate increases with increase in [oA−]and unaltered with added salts like NaClO4 and KCl. A mechanism involving complex formation between alcohol and Ru(III) which disproportionates in a slow step to Ru(I) and product by hydride ion abstraction is proposed. The Taft's plot was linear with a ρ*=−1.20.
Uranium(VI) and Thorium((IV) Complexes of Salicylideneamino Acids
Authors: Mahmoud M. R. , El‐Samahy A. , Abd El‐Hamide R. , Abdel‐Mowgood A. M. 
Published: September 2010

AbstractThe preparation of a series of new UO2(II) and Th(IV) complexes of some salicylideneamino acids is described. The complexes formed have been characterized by elemental analysis, extension of the spectrophotometric molar ratio and continuous variation methods to a three‐component complex system, IR‐spectra and conductance measurements. It is concluded that the salicylideneamino acid coordinates to the metal ion as a bivalent tridentate ligand. The bonding sites are the two oxygen atoms of the hydroxy and carboxyl groups belonging to the salicyl and amino acid moieties respectively and the central azomethine nitrogen. Furthermore, the apparent formation constants of the different complexes were determined spectrophotometrically and discussed.
Quantum Mechanical Studies of Atomic, Bond, and Molecular Polarizabilities: Application to Some Metal Hexacarbonyls of Octahedral Symmetry
Authors: Nagarajan G. 
Published: September 2010

AbstractA brief survey on the vibrational and structural studies has been made for the hexacarbonyls of chromium, molybdenum, and tungsten possessing an octahedral symmetry. The delta‐function potential model is developed and shown to be valuable in evaluating important quantities through the use of the vibrational method and the delta‐function electronic wave functions. It is then applied to the calculations of atomic polarizabilities, bond polarizabilities, contribution by the nonbonding electrons, bond perpendicular components of the polarizability, and the average molecular polarizability of both diatomic and polyatomic molecules. The delta‐function strengths, the values of the parameter c, and the atomic polarizabilities of all the atoms in the hexacarbonyls of chromium, molybdenum, and tungsten were calculated. The bond polarizabilities, contribution by the nonbonding electrons, bond perpendicular components, and average molecular polarizabilities were also calculated for these molecules. The results have been briefly discussed.
An infrared Study of Pyridine‐Pyridine and Pyridine‐H2O Interactions by the Matrix Isolation Method
Authors: Maes G. 
Published: September 2010

AbstractThe infrared spectrum of matrix isolated pyridine and pyridine‐d5 is studied in noble gas matrices. A number of vibration band splittings is observed, most of which have not yet been reported in literature. The splittings are found to be caused by two types of association, a pyridine‐pyridine one and a pyridine‐H2O complex. Information concerning the structure of the associated systems is obtained from a careful analysis of the experimental results.
Composition Isotopique du plomb total de Roches: Méthodologie Lead Isotopic Composition in Whole Rocks: Methodology
Authors: Aspirante D. Weis 
Published: September 2010

AbstractThe different stages of the lead isotopic analysis and the determination of the Pb and U concentration in whole rocks are treated. We examine successively.the dissolution of the sample;the chemical separation of Pb and U on ion exchange resin columns.the isotopic analysis of Pb by mass spectrometry with a precision better than one per mil per atomic mass unit;the determination of Pb and U contents by isotopic dilution mass spectrometry at ±1% (on samples with 1.5 to 0.1 μg of Pb and 0.8 to 0.05 μg of U);the contamination problem for the whole chemical procedure with blank values less than 3 ng of Pb;the accuracy and reproducibility of the results at the 0.1% level (by analysis of the Pb standard NBS 981 and by repeated analysis of the same sample).
NMR Studies on Imidines. I. An 1H and 13C NMR study of 10,12‐dihydroisoindolo[1,2‐b]quinazoline‐12‐one
Authors: Spiessens Luc I. , Anteunis Marc J. O. 
Published: September 2010

Abstract10,12‐Dihydroisoindolo[1,2‐b]quinazoline‐12‐one (1) was prepared and fully examined by 1H and 13C NMR spectroscopy in CDCl3 and DMSO‐d6 solution.
Exafs Studies of Calcined and Sulfided CO‐Mo HDS Catalysts
Authors: Clausen Bjerne S. , Lengeler Bruno , Candia Roberto , Als‐Nielsen Jens , Topsøe Henrik 
Published: September 2010

AbstractInformation regarding the structure of the cobalt containing phases in calcined as well as sulfided Co‐Mo/Al2O3 catalysts is obtained by analyzing the extended x‐ray absorption fine structure (EXAFS) above the Co K‐edge and comparing these results with those for model compounds. For the catalysts studied, the results show no evidence for any of the well‐ordered cobalt compounds which have been proposed to be present in such catalysts. In the calcined catalyst the Co atoms are observed to be present in quite disordered surroundings with distinct backscattering observed only from the nearest neighbor oxygen atoms. From in situ EXAFS data of the sulfided catalyst it is observed that sulfiding affects a majority of the cobalt atoms such that they now become surrounded by sulfur atoms. However, a well‐ordered cobalt sulfide does not form since only one strong backscatterer peak in the radial distribution function is observed. A comparison of the present Co EXAFS results with Mo EXAFS and Mössbauer spectroscopy measurements on the same catalysts suggests that in sulfided Co‐Mo/Al2O3 catalysts the cobalt promoter atoms seem to be located in surface positions of the Co‐Mo‐S phase. Furthermore, the present results show the necessity of carrying out experiments in situ.
The Sulphided State of Hydrodesulphurisation Catalysts Characterized by XPS
Authors: Grimblot Jean , Dufresne Pierre , And Leon Gengembre , Bonnelle Jean‐Pierre 
Published: September 2010

AbstractTypical Co or Ni‐Mo‐σAl2O3 hydrodesulphurisation catalysts are (partly) sulphided in the catalytic conditions and the questions about the structure, the sulphur content of the catalysts, the chemical state of the promotors are subject to controversial results or interpretations in the literature. In this paper, we present some results about the sulphided state of HDS catalysts by using X‐ray photoelectron spectroscopy (XPS), a powerful technique to analyze this kind of problem. In particular, the influence of sulphiding conditions on the formation of MoS2 cristallites is shown. By performing experiments under mild sulphiding conditions, the molybdenum monolayer observed in the precursor oxide is not greatly modified. Results on the extent of sulphidation expressed by the fraction of MoIV species in a sulphided environment (Mo) and the stoichiometry Sm/Mo are given. On the other hand, the reactivity towards sulphidation of the promotors (Ni or Co) is highly dependent on the localisation in octahedral or tetrahedral sites on the support or on a surface phase. In general, the octahedral sites are more easily sulphided.
STRUCTURE DU (±) ACETYL‐4 PERHYDROTHIAZINE‐1,4 METHYLCARBOXAMIDE‐3 C8H14N2O2S
Authors: Tinant B. , Declercq J. P. , Germain G. , van Meerssche M. 
Published: September 2010

AbstractFrom X‐ray analysis, crystal and molecular structure of 4‐acetyl‐1,4‐per‐hydrothiazine‐3‐methylcarboxamide has been determined.Crystal data are as follow: orthorhombic, space group Pcab, a = 12.797(8), b = 9.923(7), c = 15.533(9) Å, V= 1972.3 Å3, Z = 8.
Étude Structurale des Analogues de la Minaprine: 2. Structure Cristalline du Dichlorhydrate de L'Analogue 4‐Phényle
Authors: Michel A. , Gustin R. , Evrard G. , Durant F. 
Published: September 2010

AbstractThis study is part of a more general investigation about conformations of morpholinoethylamino pyridazines. Some of these molecules exhibit psychotropic activity related with the substitution on the pyridazine ring.The molecular structure of the title compound analyzed by X‐Ray diffraction is discussed in terms of electronic delocalization into the pyridazine ring.
Active Metal Slurries as Coupling Agents
Authors: Dams Rudy , Malinowski Marek , Geise Herman J. 
Published: September 2010

AbstractActive metal slurries, prepared by the reduction of TiCl3, TiCl4, NbCl5, MoCl5 and WCl6 with LiAlH4 in THF, can bring about the reductive coupling of benzophenone to tetraphenylethene. Yields depend critically on the metal used.
The Infra‐red Spectra of Complexes with Planar Dithio Oxamides. Part II: The Pd(LH2) 2X2 Complexes
Authors: Hofmans H. , Desseyn H. O. , Dommisse R. , Herman M. A. 
Published: September 2010

AbstractPd(II) gives square planar complexes Pd(LH2) 2X2 in acid media. X = Cl, Br, I; LH2 = Dithio oxamide (DTO), N methyldithio oxamide (RDTO) and NN′ dimethyldithio oxamide (RRDTO).These ligands act as bidentate ligands with S,S coordination. The hydrogen bonding ability is found to increase on passing from DTO to RRDTO and from Iodide to Chloride.
Détermination par Diffraction de Rayons X de la Structure de la Méphénytoïne C12H14N2O2
Authors: van Meerssche M. , Declercq J. P. , Germain G. , Bouché R. , Draguet‐Brughmans M. 
Published: September 2010

AbstractThe crystal and molecular structure of the title compound, a potent antiepileptic drug, has been established from X‐ray diffractometer data. Crystal data are as follows: orthorhombic, Pcab, a = 27.493 (12), b = 8.516 (3), c = 10.037 (4) Å, Dx = 1.23 Mg m−3 for Z = 8.
X‐Ray Diffraction Study of the Diels‐Alder Adduct of 4‐Phenyl‐1, 2, 4‐Triazoline‐3, 5‐Dione with Previtamin D3
Authors: van Meerssche M. , Tinant B. , Germain G. , Declercq J. P. , Vanmaele L. J. , De Clercq P. J. , Vandewalle M. E. 
Published: September 2010

AbstractC35H49N3O3, orthorhombic, P212121, a = 7.142 (1), b = 11.873 (4), c = 37.852 (9)Å; V = 3209.7 (15) Å3, Dx = 1.16 Mg m−3 for Z = 4. The structure has been solved by direct methods (MULTAN 80) and refined to a final R value of 0.068 for 1920 observed reflections.The absolute stereochemistry of the title compound is shown in 1; the configuration at the asymmetric carbons is C(20)R, C(17)R, C(13)R, C(14)S, C(9)R, C(6)S and C(3)S. The cyclohexene ring A is in a flattened half‐chair conformation. The tetrahydropyridazine ring B adopts a sofa like conformation with N (33) located under the mean plane of the ring. The six‐membered ring C is close to a D2 twist (boat) form. The cyclopentane ring D adopts a conformation intermediate between a half‐chair (C2 symmetry) and an envelope (Cs symmetry). Finally the urazole ring E is almost flat.
Ring Transformations of 3‐Phenyl‐4‐Tosylimino‐1, 3‐Thiazetidine‐2‐One
Authors: L'abbé Gerrit , Dekerk Jean‐Paul , Deketele Martine 
Published: September 2010

AbstractThe title compound 1 can be transformed into functionalized 5‐ and 6‐ membered heterocycles by treatment with nucleophilic reagents. For instance, the reaction of 1 with tert‐butyl isonitrile yields the two isomers 2 and 3, resulting from different positions of attack at the 4‐membered ring. Diethylaminopropyne, on the contrary, reacts only at the C2‐position of 1 giving rise to the 6‐membered ring 4 in high yield. With phosphorus ylides, three pathways, all resulting from initial attack at the C2‐atom of 1, have been observed depending on the substitution pattern of the ylide.
Spectrométrie de masse D'hétérocycles Azotes. XII. Perte de HCN a Partir des Ions Moléculaires des Aminopyridines et Structures de Divérs Ions C4H5N+.
Authors: Abmani Aziz , Aubagnac Jean‐Louis 
Published: September 2010

AbstractL'examen des spectres MIKE et CID/MIKE a permis d'établir que les ions C4H5N+. formés par perte de HCN à partir des ions moléculaires des aminopyridines n'ont pas la structure de l'ion pyrrole.
Décomposition Hétérolytique de Percarbonates de O, O‐Méthyl‐1 Phényl‐1 Éthyle et O‐Alkyle Ou O‐Vinyle en Solution
Authors: Villenave J. J. , Filliatre C. , Maillard B. , Jaouhari R. 
Published: September 2010

AbstractO,O‐α‐cumyl O‐ethyl, O‐vinyl and O‐isopropenyl peroxycarbonates (percarbontes) have been prepared from the corresponding chloroformates. Their decompositionshave been studied in triisopropylbenzene and di‐n‐butyl phtalate as solvents; in both cases the main process was the heterolysis of the peroxydic bond (Criegee rearrangement) which gave 2‐phenoxy propene. Kinetic studies have been performed using Differential Scanning Microcalorimetry; they have shown that the decomposition of O,O‐α‐cumyl O‐ethyl percarbonate is faster in di‐butyl phtalate than in triisopropylbenzene and that the rate constants depend on the initial concentrations of the solutions. From both chemical and kinetic data it has been concluded that the studied percarbonates cannot act as free radical initiators even in non polar media.
Mechanism of Ruthenium (III) Catalysed Oxidation of L‐Valine by Alkaline Hexacyanoferrate (III)
Authors: Shukla Raj Kishor 
Published: September 2010

AbstractThe kinetics of Ruthenium (III) catalysed oxidation of L‐Valine by alkaline solution of hexacyanoferrate (III) were studied by following the rate of disappearance of Fe(CN)3‐. The reaction shows zero order dependence on hexacyanoferrate (III). First order on ruthenium (III). The first order kinetics observed at lower concentration of L‐valine tends towards zero order at its higher concentration. The reaction rate decreases gradually with increasing concentration of hydroxide ion. The main oxiding species base, however, been found to be ruthenium (III) and hexanoferrate (III) is merely used up in generating the ruthenium (III) species from ruthenium (II) formed. A suitable reaction mechanicals involving formation of transit complex between ruthenium (III) species and valine has been proposed. Evidence for complex formation is Obtained by Michselismanten reciprocal plot. Thermodynamic parameters have been recorded and the final rate law has been devised. The product as a result of oxidation has been identified and the different properties have been assigned by using the new techniques.
Mass Spectrometric Study of (Me)4‐n Si(Allyl)n (n = 1‐4)
Authors: Naessens L. A. , Claeys E. G. , Hoste S. , van Der Kelen G. P. 
Published: September 2010

AbstractThe mass spectra of (Me)4‐n Si(Allyl)n (n = 1‐4) are discussed in detail. In these compounds odd‐electron ions play a somewhat more important role in the decay processes than in the mass spectra of other organosilicon compounds where the even‐electron ions are principally formed. The main features of the mass spectra are: the low abundance of molecular ions, hydrogen transfer with formation of cyclic ion‐structures and elimination of a number of neutral fragments.Some similarities between thermolysis and mass spectrometric fragmentation of related organosilicon derivatives are also discussed.
Mass Spectrometric Study of Some Si‐N Compounds (CH3)4‐n Si{N(CH3)2}n (N = 1‐4)
Authors: Naessens L. A. , Claeys E. G. , van Der Kelen G. P. 
Published: September 2010

AbstractThe mass spectra of the various methyl dimethylaminosilanes were studied and the fragmentation processes are discussed. Characteristic features of the mass spectra of these compounds are: (i) the breaking of the Si‐N bond occurs more readily than that of the Si‐C bond (ii) the abundant molecular ions decompose preferably by loss of radicals: CH3., N(CH3)2. and H. (iii) the most likely fragmentation process for the base peak ion consists of elimination of neutral N containing molecules and occurs simultaneously with H or CH3 shift.