bluuebunny/crossref_metadata_2025 huggingface dataset:
Étude théorique de l'isomérisation Z‐E des oximes C‐substituées1
Authors: Leroy Georges , Nguyen Minh‐Tho , Sana Michel , Villaveces José‐Luis
Published: September 2010

Dans ce travail, nous avons étudié les isomérisations s cis‐ strans et Z‐E de l'hydroxy‐formaldoxime et de l'azido‐formaldoxime. Tous nos calculs ont été effectués en utilisant la méthode LCAO‐SCF‐MO de Roothaan. La base minimale STO‐3G, avec ou sans interaction de configurations, et la base étendue 4‐31G du groupe de Pople ont été employées.

Au total, nous avons montré que le mécanisme d'isomérisation dépend fortement de l'effet de substituants et les calculs nous permettent de rationaliser certains faits expérimentaux.
Synthesis and reactivity of polychlorocyclopentanones
Authors: De Buyck L. , De Kimpe N. , Verhé R. , Courtheyn D. , Schamp N.
Published: September 2010

Selective chlorination methods were elaborated for the conversion of cyclopentanone into 2, 2, 5, 5‐tetrachloro‐, 2, 2, 3, 5, 5‐pentachloro‐ and 2, 2, 3, 3, 5, 5‐hexachlorocyclopentanone. Dimethylformamide‐hydrogen chloride mixtures served as catalysts for enolization and for dehydrochlorination to chlorinated cyclopentenones.

The reactivity of the polychlorocyclopentanones was tested towards zinc (in acetic acid, methanol or acetone) and towards bases in protic solvents. A number of chlorinated cyclopentenones, substitution products and open chain compounds (Grob elimination) were obtained in good yields.
Diterpenes acycliques de cystoseiracées (phéophycées) de la côte méditerranéenne
Authors: Combaut Georges , Francisco Christian , Piovetti Louis , Gonzales Emmanuel , Teste Jean , Codomier Louis
Published: September 2010

A set of mediterranean brown algae belonging to Cystoseira family is analysed by a G. L. C. and I. R. method. Easy determination of diterpenic compounds is presented. Among all the samples analysed, the only one Cystoseira elegans contains eleganolone, epoxy eleganolone and elegandiol as the atlantic Bifurcaria bifurcata.
Novel metabolites from some predator‐prey pairs1
Authors: Cimino G. , De Stefano S. , De Rosa S. , Sodano G. , Villani G.
Published: September 2010

The isolation of known and novel metabolites from several predator‐prey pairs is reported. The usefulness of secondary metabolites as tracers to detect predation is also discussed.

Many species of nudibranchs are closely associated with their food species, which include sponges, bryozoans and coelenterates, and are often so closely associated that they easily fit the criteria for a symbiotic association.

The nudibranch associations have a high potential2 as models for the study of basic biological problems such as the chemorecognition and chemotaxis, the settling and metamorphosis of veligers, the defence mechanisms. The chemistry of these biological problems is poorly understood, with the exception of few reports3 related to the third point, namely the isolation of toxic or antifeedant substances from both preys and predators.

We have undertaken a study of several predator‐prey pairs with the intention, at the present time, of the isolation and structural elucidation of the organic natural products accumulated by the predators during the diet because some of these compounds may have a number of the biological properties listed above.

In addition we investigated the use of the secondary metabolites as a tracer to detect predator‐prey pairs.
Mycosporine aminoacids and related compounds from the eggs of fishes
Authors: Chioccara F. , Delia Gala A. , De Rosa M. , Novellino E. , Prota G.
Published: September 2010

A survey of the distribution of mycosporines in marine organisms has shown that these compounds, previously found only in a few species, are almost ubiquitary among invertebrates and occur also in fishes, mainly in ripe eggs. These were found to contain, in addition to known members of the series, two related metabolites which were isolated and formulated as the enolised β‐diketones 4 and 5, the latter corresponding to the postulated precursor of the mycosporine chromophoric system.
Dissociation Constants of Acetic Acid and Protonated Tris(Hydroxymethyl)‐Aminomethane in 80 mass% 2‐Methoxyethanol/20 Mass % Water in the Range 10 to 50°
Authors: Shanbhag P. M. , Bates Roger C.
Published: September 2010

Electromotive‐force measurements of cells without transference have been used to determine the thermodynamic dissociation constants of acetic acid and protonated Tris (hydroxymethyl)aminomethane (Tris.H+) in the mixed solvent 80 mass% 2‐methoxyethanol/20 mass% water from 10 to 50°. Hydrogen gas electrodes and silver‐silver chloride electrodes were used. Thermodynamic constants for the dissociation process were derived. The enthalpy of dissociation of Tris.H+ was also determined by titration calorimetry and found to be in acceptable agreement with the value obtained from the emf measurements. Allowance for association of the ions of the salts used altered the calculated pK values by about 0.03 unit (acetic acid) and 0.06 unit (Tris.H+).
Rapid Extraction and Spectrophotometric Determination of Tantalum With N‐P‐Chlorophenylbenzohydroxamic Acid
Authors: Agrawal Y. K. , Patel S. A.
Published: September 2010

A rapid and sensitive method for the extraction and spectrophotometric determination of tantalum in presence of niobium with N‐p‐chlorophenylbenzohydroxamic acid has been described. The tantalum‐N‐p‐chlorophenylbenzohydroxamic acid (Ta‐p‐Cl‐BHA) complex is extractable into toluene or benzene in HCl media. The addition of ammonium thiocyanate and malachite green (MG) increases the molar absorption coefficients of the complexes 7.8 × 103 and 4.0 × 1041 mol−1 cm−1 respectively.
Tautomerism of Some Aminomethylphenols in Aqueous Solution
Authors: Martinek H. , Wolschann P.
Published: September 2010

The tautomerism of several aminomethyl‐phenols and‐naphthols in aqueous solution is studied, using electron absorption spectroscopy. From the UV‐VIS‐spectra at different pH‐values both pK‐values can be calculated, together with the proton transfer equilibrium constant KPT, At neutral pH the aminomethyl‐phenols and‐naphthols exist mainly as zwitter ions without intramolecular hydrogen bond. Log KPT follows a linear relation to ApKa.
Synthesis, 1H‐and 13C‐NMR Spectra of 2‐Tropanone Derivatives. The “6‐Endo” or “6‐Exo”‐8‐Methyl or Phenyl‐2‐Oxo‐8‐Azabicyclo of 3,2,1]‐Oct‐3‐Ene‐6‐Carbonitrile and 3,4‐Dihydrogenated Analogues
Authors: Lepoivre J. A. , Dommisse R. A. , Esmans E. L. , van Luppen J. J. , Merckx E. M. , Alderweireldt F. C.
Published: September 2010

The 1,3‐dipolar addition reaction of acrylonitrile to the betaine 1‐phenyl or methyl‐3‐oxidopyridinium is not so highly regioselective as generally assumed. New regioisomers are isolated. Their structures are proven by mass spectroscopy and proton‐and carbon‐NMR spectroscopy. Some 3,4dihydroderivatives are also prepared.
Reactions of 2‐(Tert‐Butylimino)‐3‐Methyl‐4‐Tosylimino‐1,3‐Thiazetidine
Authors: L'abbé Gerrit , Sorgeloos Dominique , Toppet Suzanne , King Geoffrey S. D. , Meervelt Luc Van
Published: September 2010

This paper describes the reactivity of the title bis(imino)thiazetidine in terms of three reactivity centers of the molecule; C2, C4 and C=NTs. Reactions have been carried out with nucleophilic reagents (NaOMe, NaSEt, KCN and malonic ester/DMSO/NaH), hydrazoic acid and electron‐rich olefins (enamines and ynamines), giving rise to products 2‐10. The two products, 9‐and 10, obtained in equal amounts from 1 and N,N‐diethylaminopropyne have been subjected to a detailed analysis by spectral methods and the structure of one of them (10) has been confirmed by the determination of its crystal structure.
Enamine Chemistry, Part XXI. N‐and/or C‐substitution (alkylation, acylation) of ethyl 3‐amino‐2‐butenoate. the preparation of 2‐substituted 4‐methyl‐1,3‐thiazine‐6‐thiones
Authors: Shabana R. , Rasmussen J. B. , Lawesson S.‐O.
Published: September 2010

Alkylation of ethyl 3‐amino‐2‐butenoate, 1, with methyl iodide, ethyl iodide, and benzyl bromide gave both C‐ and N‐alkylated products (contrary to earlier findings) the ratio of which was determined by GLC. Methylation of 1 was studied under different conditions (solvent, reaction time, and temperature). Also the sodium salt of 1 was reacted with methyl iodide and gave both C‐ and N‐methylated products. Compound 1 reacted with acyl chlorides RCOC1 (RCH3 (a), CH(CH3) (b), C(CH3)3 (c), C6H6 (d), ClCH2 (e)) giving both N‐acylated products 6 (Z) and 7 (E), and C‐acylated products 8 and 8'. Compounds 6 and/or 7 reacted with 2, 4‐bis (4‐methoxyphenyl)‐1,3,2,4‐dithiadiphosphetane‐2,4‐disulfide, 5, giving N‐thioacylated ethyl 3‐amino‐2‐butenoate, 9, and 2‐substituted 1,3‐thiazine‐6‐thiones, 11 (main product). A similar reaction of 8a with 5 gave ethyl 3‐amino‐2‐thioacetyl‐2‐butenoate, 13. The 13C NMR data for the compounds 6, 7, 8, 11, 13, and to some extent 9 are presented.
Alkaloids of Vinca Rosea L Isolation and Identification of Coronaridine
Authors: Taeye Leo De , Bruyn André De , Pauw Christiaan De , Verzele Maurice
Published: September 2010

We report on the isolation and the identification of the alkaloid coronaridine from Vinca rosea L. The 1H NMR data are discussed.
Synthesis of symmetrical 1,6‐dihetero‐6aλ4‐thia‐3,4‐diazapentalenes from 5‐amino‐1,2,3,4‐thiatriazole
Authors: L'abbé Gerrit , Vermeulen Guido
Published: September 2010

1,6‐Dioxa‐6aλ4‐thia‐3,4‐diazapentalenes 7 and 1,3,4,6‐tetraaza‐6aλ4‐thiapentalenes 15, two new classes of compounds with single bond‐no bond resonance, have been prepared by reaction of 5‐amino‐1,2,3,4‐thiatriazole 4 with acyl chlorides and imidoyl chlorides. In the latter case, the salts of 5‐imino‐Δ3‐1,2,4‐thiadiazolines 12 were first isolated and subsequently reacted with a second equivalent of imidoyl chloride. This also led to the synthesis of unsymmetrically substituted 1,3,4,6‐tetraaza‐6aλ4‐thiapentalenes. In the presence of bases, the salts 12 decompose via the isolable free bases 13 into N‐cyanoamidines 14 and sulfur. Treatment of the dioxathiapentalenes 7 with P4S10, or direct thiobenzoylation of 4 gave the 3,4‐diaza‐1,6aλ4‐trithiapentalenes 9.
Configurational Stability of Methylneophylphenyltin 1‐(R)‐Phenyl‐2‐(5)‐Dimethylaminopropoxide
Authors: Gielen Marcel , Eynde Ivan Vanden
Published: September 2010

The title compound, (PhMe2CCH2)PhMeSn‐O‐CHPhCHMeNMe2 is configurationally stable within the NMR time scale and does not undergo any fast intermolecular exchange of alkoxy groups.
Surface Tension of Freshly Formed Surfaces of Surfactant Solutions
Authors: Rillaerts E. , van Havenbergh J. , Joos P.
Published: September 2010

A method is described to obtain the dynamic surface tension at an expanding interface. This method consists by receeding a meniscus inside a capillary, the surface at the meniscus is continuously renewed. A simple approximation is given for the dilatation. Experimental results are considered by applying the theory of Van Voorst‐vader. Good agreement between theory and experiment is achieved.
Problèmes relatifs a la détermination de la constante d'acidité de l'acide hypochloreux dans les saumures de NaCl
Authors: De Meyer M. , Levert J. M.
Published: September 2010

This paper studies the equilibrium HOCl
equation image
in NaCl brines and the variation of the apparent constant (ka) with ionic strength and temperature. Several reactions (decomposition, chloride formation and loss of Cl(I)) that remove the equilibrium are also examined. The brine acidity is experimentally determined and compared to the concept of pH.
The Correlation Between the Polarographic and Structural Parameters of Alizarin and its Substituents
Authors: Qureshi G. Ali
Published: September 2010

The correlation between the half‐wave potentials and Hammett substitution constants of 8 substituents of 1,2 dihyroxy anthraquinone (Alizarin) are worked out. These substituents are reduced in one step on the DME showing the similar degree of reversibility fulfilling the Hammett substitution relationship.

The nonlinearity obtained by the 5‐sulphonated substituents of Alizarin and Alizarinfluorine blue is attributed to their adsorption nature on ME at the measured pH.
Radioimmunoassay of 11α, 15‐Dihydroxy‐9‐Keto‐Prosta‐5, 13‐Dienoic Acid (Prostaglandin e2) and 9α, 11α, 15‐Trihydroxyprosta‐5, 13‐dienoic acid (prostaglandin f2α) in human plasma
Authors: Lijnen P. J. , Verschueren L. J. , Amery A. K.
Published: September 2010

A radioimmunoassay of prostagland in E2, (11α, 15‐dihydroxy‐9‐keto‐prosta‐5, 13‐dienoic acid; PGE2) and prostagland in F2α (9α, 11α, 15‐trihydroxy‐prosta‐5, 13‐dienoic acid; PGF2α) is described after an extraction‐chromatographic separation procedure of the plasma samples. The recovery of the extraction procedure averaged respectively 98 and 97.5% while the mean recovery after extraction and chromatography was 69.8% and 80.8%.

The intra‐assay variation, checked by multiple analysis of a plasma pool, averaged 7.65% for PGE2 and 5.50% for PGF2α. The inter‐assay variation investigated by measuring the PGE2 and PGF2α concentration in different plasma samples on two occasions, averaged 7.3% for PGE2 and 6.9% for PGF2α.

The prostagland in E2 and F2α concentration increased gradually by delaying the centrifugation of the blood samples after withdrawal, probably due to release by blood platelets. Addition of a prostagland in synthesis inhibitor such as indomethacin prevented the in vitro prostaglandin synthesis as reflected by the lower (p<0.001) plasma values for PGE2 and PGF2α compared to the values obtained without indomethacin.
Coordinative Role of Alkali Cations in Organic Reactions. VI. Molecular Transformation of Benzil to Benzilic Acid
Authors: Poonia Narinder S. , Porwal Prafulla K. , Sen Swagata
Published: September 2010

Studies on the rearrangement of benzil (1) to benzilic acid (2) in the presence of caustic alkalis (M+OH−) reveal that the transformation is triggered by 1‐M+ coordination and is propagated by a nucleophilic attack of OH− on the M+‐complexed 1. Solid 1‐M+OH− complexes can be isolated from CHCl3‐EtOH (1:1) medium which can be transformed to M+‐benzilate on refluxing. Conductometric studies reveal 1‐M+ coordination in EtOH‐water (transformation medium) while UV spectrophotometric studies reveal that the presence of a Lewis acid is a prerequisite for the 1 to 2 transformation to take place. A modified mechanism for the transformation is proposed.
A short and stereoselective entry into the 2‐substituted eudesmane series
Authors: Audenhove Martine Van , Keukeleire Denis De , Vandewalle Maurits
Published: September 2010

The photocycloaddition reaction of (‐)‐piperitone(2') and 1, 2‐bis (trimethylsiloxy) cyclobutene (1) occurs with complete stereoselectivity. Face subsequent transformation leads to the cis‐2, 5‐decalanedione, which is a suitable intermediate for the 2‐substituted eudesmane skeleton.
Benzohydroxamic Acid as an Indicator for Titrimetric Determination Of Zirconium
Authors: Agrawal Yadvendra K.
Published: September 2010

A titrimetric method has been developed for the determination of zirconium using benzohydroxamic acid. The effect of various metal ions on the determination of zirconium is discussed.
The Classification of Iron Meteorites. A Reappraisal of Existing Classification
Authors: Massart D. L. , Kaufman L. , Coomans D. , Eabensen K. H.
Published: September 2010

A new non hierarchical clustering procedure is used to evaluate an existing classification of iron meteorites. It is shown that the classification obtained resembles the existing classification to a large degree. This confirms the consistency of both the clustering method and the existing classification. The principal disagreement between the existing classification and the clustering concerns the so‐called anomalous meteorites. The reason for this disagreement is discussed.
Neutron Activation Analysis of the Trace Element Molybdenum in Urine of Healthy Persons
Authors: Cornelis R. , Versieck J. , Desmet A. , Mees L. , Vanballenberghe L. , Gent Rijksuniversiteit
Published: September 2010

Neutron activation of Mo in urine was performed by radiochemical separation, both via the 101Mo (T1/2 14.6 min) and via the 99Mo (T1/2 66.2 h)‐99mTc (6.02 h). The urinary excretion of Mo of 9 healthy individuals ranged from 11.1 up to 88.0 μg. day−1. The variation of the Mo‐excretion in the course of the day was studied as well.
The Determination of Boron, Carbon and Nitrogen in Zircaloy by Charged Particle Activation Analysis
Authors: Mortier R. , Strijckmans K. , Vandecasteele C.
Published: September 2010

Charged particle activation analysis is used for the determination of boron, carbon and nitrogen in zircaloy. Carbon can be determined instrumentally using the 12C (d,n) 13N reaction. For the determination of boron and nitrogen the 10B (d, n) 11C and the 14N (α, αn) 13N reactions are used. 11C is separated as 11Co2 formed by dissolution of the sample in an oxidizing solution. Carbondioxide is trapped in sodiumhydroxyde. 13N is separated as 13NH3 which is trapped in 10 ml of 0.2 M hydrochloric acid. The yield of the chemical separations is determined experimentally. Concentrations of 0.163, 113.4 and 36.8 μg g−1 are obtained for boron, carbon and nitrogen respectively.
Influence of Photoplate Evaluation Parameters in Spark‐Source mass Spectrometric Analysis
Authors: Verbueken A. , van Grieken R.
Published: September 2010

In view of optimising the multi‐element spark‐source mass spectrometric analysis of biological material by photoplate detection, the effect of changing some important parameters in the densitometry, linearisation procedure and further data evaluation has been investigated. In the used procedure, the relative exposure values for the different stages on the photoplate are derived from the overall experimental relative blackening data rather than from coulometer readings. This approach is especially attractive when the simple Seidel linearization method is applied.

The influence of changing the maximum transmittance setting for continuous background correction appeared not to be critically important in practice. The setting of boundaries of a linear working range of the photoplate characteristic curve and its influence on the final concentration value was studied in detail. A significant difference was found, especially in trace element analysis, between the results obtained by presuming intuitively a routine dynamic range and by using a carefully established range. A comparison was also made with the more laborious Hull linearization procedure. The importance of the assumed linear range on the analytical data quality has to be emphasized.
Determination of the Main, Minor and Trace Elements in Lead/Tin‐Based Solder by Atomic Absorption Spectrophotometry
Authors: Carleer R. , François J.‐P. , van Poucke L. C.
Published: September 2010

A procedure is described for the determination of tin, lead, bismuth, copper, iron, silver, cadmium and zinc in Sn‐Pb alloy, composed of ca. 50% Sn, 47% Pb, and 3% Bi, by means of atomic absorption spectrophotometry. The sample is dissolved in aqua regia. Tin and lead are determined against standard solutions in which the Sn/Pb ratio is approximately the same as in the alloy. The relative precision, with respect to gravimetric determinations, is ca. 1.5%. For the bismuth, copper, iron, silver, cadmium and zinc determinations the standard addition method has been used.
Contribution a L'étude électrochimique de dérivés de L'acide mercapto‐2 pyridine carboxylique‐5
Authors: Lejeune R. , Vandenbalck J. L. , Patriarche G. J. , Lapière C. L.
Published: September 2010

5‐methoxycarbonyl‐1‐methyl‐2‐methylthio‐pyridinium iodide and 5‐carboxyl‐methyl‐2‐methylthio‐pyridinium iodide have been studied by recent polarographic and voltammetric technics.

The results obtained with a continous and an alternative polarographic current were compared to those obtained by cyclic voltammetry. These former experiments and a study as a function of pH lead to proposing a reduction mechanism of the thioether function with is the reactive site of these molecules.

A complementary study as a function of concentration permetted to establish the optimal conditions for quantitation and the detection limit reached with classical and differential pulse polarographies.
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

The 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

The 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

The 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

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

Nine‐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

The 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

This 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

2‐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

A 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

Kinetics 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

The 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

The 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

A 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

The 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

The 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

10,12‐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

Information 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

Typical 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

From 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

This 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

Active 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

Pd(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

The 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

C35H49N3O3, 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

The 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

L'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

O,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

The 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

The 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

The 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.
The Probable Phase Composition of the Mineral in Sound Enamel and Dentine
Authors: Driessens F. C. M. , Verbeeck R. M. H.
Published: September 2010

A reevaluation of the chemical, physical and physicochemical properties of the mineral in tooth enamel and dentine shows that the current models can not adequately account for the observed characteristics. On the basis of thermodynamical and solid state chemical principles an alternative model for the mineral in tooth enamel and dentine is proposed. According to the model the tooth enamel mineral consists of a magnesium whitlockite, a sodium‐ and carbonate containing apatite and a slightly carbonated hydroxyapatite approximately in the ratio 1: 1: 3. The latter phase also contains the chloride and fluoride ions of the mineral. The consistency of this three‐phase model is discussed. Dentine mineral appears to have qualitatively the same phase composition as bone mineral, although the relative amounts of the three constituting mineral phases differ considerably.
Structures et Étude Comparative des Géométries de Six Dérivés du Cyano‐1 Diphényl‐1, 2 Cyclopropane
Authors: Tinant B. , De Block I. , Declercq J. P. , Germain G. , van Meerssche M. , Leroy G. , Weiler J.
Published: September 2010

The structure of six l‐aryl‐l‐cyanocyclopropane derivatives were solved by direct methods (MULTAN) from diffractometer data. (I): r‐I‐cyano‐c‐2‐p‐dimethylamlnophenyl‐1‐phenylcyclopropane C18 H18 N2 is orthorhombic, P21 21 21 with a = 20.537(6), b = 9.010(2), c = 7.956(3)Å, z = 4. (II): r‐l‐cyano‐c‐ ‐2‐ ‐ v‐dimethylaminophenyl‐1‐p‐nitrophenylcyclopropane C 18H17N3O2 is triclinic, P1 with a = 14.547(5), b = 8.521(2), c = 6.402(2)Å, α = 93.59(2), β = 96.37(3), γ = 88.30(2)°, = 2. (III): r‐l‐cyano‐c‐2‐p‐dimethylaminophenyl‐t‐3‐methyl‐l‐p‐nitrophenylcyclopropane C 19H19N3O2 is triclinic, P1 with a = 9.873(3), b = 10.134(3), c = 9.335(3)°, α = 73.10(2), β = 84.07(2), γ = 98.68(2)°, Z = 2. (IV): r‐l‐cyano‐c‐2‐ (p‐dimethylamino‐α‐methylbenzyl) ‐t‐3‐methyl‐1‐p‐nitrophenylcyclopropane C21H23 N3 O2 is monoclinic, C2/c with a = 23.837(5), b = 12.389 (3), c = 14.374(5)Å, β = 113.82°, Z = 8. (V): r‐l‐cyano‐l‐p‐nitrophenyl‐c‐2‐ phenylcyclopropane C16H12 N2O2 is monoclinic, P21/c with a = 7.152(1), b = 17.814(6), c = 10.717(4)Å, β = 96.40(3)°, Z = 4. (VI): r‐l‐cyano‐t‐3‐methyl‐l‐p‐nitrophenyl‐c‐2‐phenylcyclopropanc C17H14N2O2 is monoclinic, P21/a with a = 7.783(2), b = 24.492(4), c = 8.501(1)Å, β = 115.59(1)°, Z = 4. The substituent induced bond length asymmetries observed in these cyclopropane derivatives are in good agreement with analysis of Allen (1980). There is no evidence of conjugation transmission from an electrodonor substituent to an acceptor one through the small ring.
Carbon‐13 Chemical Shifts of Three Oxo‐, Six Monohydroxy‐, and Six Dihydroxycyclohexyl Derivatives of Procyclidine
Authors: Paeme G. , Grimée R. , Vercruysse A.
Published: September 2010

In order to elucidate the metabolic pattern of procyclidine in the rat, a variety of OXO‐, monohydroxy‐, and dihydroxycyclohexyl derivatives of this drug were synthetized. All of them have been identified by 13C‐NMR spectroscopy.
Spectres RMN ‐1H et ‐13C de Quelques Quinoléines et Quinaldines Mono et Disulfonees
Authors: Gelbcke M. , Masiala‐Tsobo C. , Dumont L. , Parmentier F. , Grimée R.
Published: September 2010

Proton and carbon‐13 chemical shifts and coupling constants are reported for one disulfonated and four monosulfonated quinolines, two monosulfonated and two disulfonated quinaldines. Substituent effects for the alpha, ortho, meta, para and peri positions are discussed.
Cavernosine, a Novel Ichthyotoxic Terpenoid Lactone from the Sponge Fasciospongia Cavernosa
Authors: Braekman J. C. , Daloze D. , Bertau R. , Macedo De Abreu P.
Published: September 2010

Cavernosine, a novel ichthyotoxic terpenoid lactone has been isolated from the sponge Fasciospongia cavernosa. Its structure has been determined by spectral analysis, chemical degradation and correlation with β‐ionone.