bluuebunny/crossref_metadata_2025 huggingface dataset:
N‐Methyldihydrostreptomycin Synthesis, Structure, and Antibacterial Activity
Authors: Vanderhaeghe H. , Totté J. , Claes P.
Published: September 2010

Reductive methylation of dihydrostreptomycin yielded a new derivative, N‐methyl‐dihydrostreptomycin. By this reaction the N‐methyl‐L‐glucosamine fragment of dihydrostreptomycin is converted into N‐dimethyl‐L‐glucosamine. The structure of this derivative is confirmed by degradation and NMR spectroscopy. Methylation of the monomethylamino function of dihydrostreptomycin resulted in a complete loss of antibacterial activity.
Étude par R.M.N. De Haute Résolution de L'état Adsorbé. III. Mise en Évidence de Points de Congélation et Interprétation
Authors: Derouane Eric G.
Published: September 2010

In a former study (I), we have shown that an adsorbed system was to be considered as composed of three distinct phases on the N.M.R. viewpoint. In the present paper we discuss the problem of the freezing point of the adsorbate contained in the micro‐ and macropores. It is found that freezing points are considerably lowered as a result of interactions between molecules themselves, and between the molecules and the surface. The adsorbate, contained in the macropores, is found to be unperturbed and has a freezing point similar to that of the pure liquid. In the micropores, the lowering of the freezing point is of about 10 to 20 deg;C depending on the natures of both the adsorbate and the support. The phenomenon is found to be completely reversible, and a possible explanation is proposed in term of a lowering of the adsorbate activity in the micropores as a result of the interactions with the surface.

It seems well established that N.M.R. provides a very easy tool for the determination of freezing points in the adsorbed state. An extension is also possible for the study of polymer swelling.
Complexes du Fer‐Carbonyle Avec L'acétylène et ses Dérivés. V. Structure de Fe2(CO)6 · (CH3C2CH3)2CO
Authors: Piron J. , Piret P. , Meunier‐Piret J. , van Meerssche M.
Published: September 2010

The structure of one of the products of the reaction between Fe2(CO)9 and CH3C  CCH3 has been determined by X‐ray diffraction. The monoclinic crystals belong to the space group P21/c. The dimensions of the unit‐cell are a = 8.34, b = 26.16, c = 8.31 Å,β = 112.4°, Z = 4. The complex can be formulated as: magnified image.
Synthesis of 5‐Isovaleryl‐3,3‐Dimethyl‐1,2,4‐Cyclopentanetrione, A Homologue of Tetrahydrohulupone
Authors: Verzele M. , De Pooter H. , Schamp N.
Published: September 2010

3,3‐Dimethyl‐1,2,4‐cyclopentanetrione is prepared in high yield by hydrolysis and debromination of the easily accessible 2,3,5,5‐tetrabromo‐4,4‐dimethyl‐2‐cyclopentenone. Acylation with isovaleric anhydride affords the title compound.
Preparation of Octa‐n‐Methyl‐ and Tetra‐n‐Methylkanamycin
Authors: Claes P. , Vanderhaeghe H.
Published: September 2010

Two N‐methylated derivatives of kanamycin A were synthesized. The first compound, octa‐N‐methylkanamycin, was prepared by reductive methylation of kanamycin A. The second, tetra‐N‐methylkanamycin, was obtained by catalytic debenzylation of tetra‐N‐benzyl‐tetra‐N‐methylkanamycin. Both derivatives were devoid of antibacterial activity.
La Cryométrie de Quelques Systèmes Binaires: Coefficients D'Activité Thermodynamique Dans le Système Ternaire Nitrate de Lithium+Nitrate de Sodium+Eau et Dans les Système Binaires Associés
Authors: Vîlcu R. , Irinei F.
Published: September 2010

The present work studies the characteristics of the ternary LiNO3 + NaNO3 + H2O system and of the associated binary solutions LiNO3 + H2O and NaNO3 + H2O, in the concentration range 1, 5‐3 molal.

The change of ion‐ion and ion‐solvant type interactions in ternary systems as regard to the binary systems, are evidenced by the δ and δo deviation functions.

To calculate these functions use is made of the deviations from additivity of Gibbs thermodynamic potential in the ternary system. In the same time a method is presented for calculating Harned's coefficients and activity coefficients of individual electrolytes by means of deviation functions, δ.
L'Étude Théorique des Systèmes Periodiques: IV. Formulation Matricielle de la Méthode LCAO‐SCF‐CO
Authors: André J. M. , Delhalle J. , Leroy G.
Published: September 2010

On déduit une formulation matricielle générale de la méthode des orbitales cristallines autocohérentes (LCAO‐SCF‐CO). L'organisation du programme de calcul correspondant (POLYCOD) est décrite dans la dernière partie de ce travail.
Phase Transitions in Monolayers. Effect of a Second Component on the Transition Pressures
Authors: Joos P.
Published: September 2010

Phase transitions in monolayers are divided into two groups regarding if a flat part in the π‐A curve occurs or only a knikpoint. This distinction is related to the miscibility or immiscibility of the two modifications in the monolayer. Phase transition were compared with monolayer collapse. Upon compression the molecular area decreases till the molecules are highest packed, but instead of collapse by further compression, the molecules undergo a reorientation to a smaller limiting molecular area.

The effect of a second component on the transition pressure was examined theoretically and the corresponding equations derived, starting from the chemical potential in the monolayer as elaborated by Defay et al. The transition pressure depends on the amount of the second component added to the system and is in disagreement with the Goodrich method. The effect of cholesterol on the phase transition in a stearic and myristic acid and ethylpalmitate monolayer was examined. When the two modifications are immiscible (myristic acid and ethylpalmitate) by addition of cholesterol the phase transition disappears and causes a condension of the expanded monolayer. In the case of stearic acid (miscible modifications) addition of cholesterol yields no appreciable difference in the surface pressure at the transition point. For this system the collapse pressure shows anomalities.
NMR‐Experiments on Acetals: XXIII The Ring Shape of m‐Dioxanes, m‐Dithianes and m‐Thioxanes
Authors: Gelan J. , Swaelens G. , Anteunis M.
Published: September 2010

It is shown that the criterion of Lambert (allowing the description of ring shape) and the recent extension by Buys (allowing the calculation of torsion angles of parts of the ring) can be applied to unequal‐populated conformational pairs and to anancomeric systems. The results so obtained for m‐dioxanes, m‐dithianes, and m‐thioxanes are discussed in the light of the pecularities of these ring systems.
Étude des Réctions de Substitution Dans la Série des Thiénopyridines
Authors: Eloy F. , Deryckere A.
Published: September 2010

A partir de la thiéno[3,2‐clpyridone et de son isomère [2,3‐c], on a synthétisé des thiénopyridines contenant des substituants fixés sur les noyaux de la pyridine et du thiophène. La position des substituants a été vérifiée par l'étude des spectres RMN.
Synthèse des Acides O.Acétyl et O. Benzoylthiophènecarboxyliques et de Leurs Chlorures D'Acide et Esters
Authors: Pirson P. , Schonne A. , Christiaens L.
Published: September 2010

The unambiguous synthesis of five new o. benzoyl and o.acetylthiophenecarboxylic acids and simple derivatives (acid chlorides and esters) is reported (I‐II: table II). These o. ketoacids might present the ring‐chain tautomerism like o. formylacids. I. R.‐N. M. R. spectroscopy and X. ray diffraction have been used to determine the positions of the substituent groups and the structure of these compounds. The physical results will be subsequently published.
Étude de Complexes Moléculaires: II. La Conductivité Électrique du Complexe de la Phénothiazine Avec le p‐chloranile
Authors: Barigand[1] M. , Tondeur J. J. , Országh J.
Published: September 2010

The d. c. conductance of the solid complex obtained by melting stoechiometric amounts of phenothiazine and p‐chloranil is measured. The order of magnitude and the dependence of the conductivity from the temperature show that this complex behaves like a semiconductor. The study of the influence of the granulometry, the nature and the pressure of the atmosphere surrounding the sample permits to conclude that the conduction occurs mainly by a superficial mechanism.
Vicinal Exocyclic Coupling and Constitutional Problems
Authors: Anteunis M.
Published: September 2010

Vicinal exocyclic coupling values are larger for (pseudo) axial substituents than for (pseudo) equatorial substituents. This behaviour which seems to be of fundamental nature, may be used for solving constitutional problems. Exceptions are found in pseudorotameric systems when strongly coupled complex spin systems are involved.
Contribution á L'Étude des Arséniures de Fer, Cobalt et Nickel
Authors: Naud J. , Breckpot R.
Published: September 2010

The stable phases in the systems FeAs, CoAs and NiAs obtainable by thermal synthesis and by precipitation with arsine have been examined by X‐ray diffraction and their electrochemical and thermodynamic behaviour compared.

Precipitation of the compounds with Me/As ratio near to one is accompanied by hydrogen evolution whilst the metal rich derivatives obtainable only with nickel (Ni11As8, Ni5x As2) are the result of an oxydo‐reduction reaction function of solution pH with as second member of the couple AsO.

Cathodic polarisation leads to metal rich compounds in the case of iron (Fe2As) and nickel (Ni11, As8 and Ni5As2). In all cases excess metal is bound to the substrate in an amorphous non ferromagnetic form.
Évaluation des Potentiels D'Ionisation et des Électroaffinités des Hydrocarbures Saturés et Insaturés et de Quelques Radicaux au Moyen du Modèle de L'Électron libre (F.E.M.)
Authors: Jannes G. , Puttemans J. P.
Published: September 2010

This study is based on the existing linear relationship between the energy of the highest occupied orbital and the experimental ionization potential as well as on the linear relationship between the energy of the lowest free orbital and the electro‐affinity. The energies of these levels are deduced from F.E.M. calculations.

This method yields results in the different series favourably comparable with those obtained by more sophisticated techniques. Thanks to existing experimental values, it was possible in the aromatics to evaluate unknown electroaffinities, reduction potentials as well as half‐wave potentials.
Kinetics of Oxidation of trans‐2‐Chlorocyclohexanol with Bromine
Authors: Kudesia V. P.
Published: September 2010

The kinetics of oxidation of ttans‐2‐chlorocyclohexanol with bromine has been studied at 40°C. The reaction has been found to obey second order kinetics, with first order dependence on each reactant. The thermodynamic activation parameters are reported. A cyclic mechanism is suggested.
Theoretical Study of Small Ring Compounds. II. Cyclopropane, Methylcyclopropane and Dimethylcyclopropanes
Authors: André Jean‐Marie , André Marie‐Claude , Leroy Georges
Published: September 2010

On décrit des calculs «ab initio» de la fonction d'onde de l'état fondamental du cyclopropane et de ses dérivés méthylé et diméthylés. On discute les relations entre la structure électronique et les propriétés statiques et dynamiques de ces molécules.
Differences in Solvent‐Effects on the Association of Primary, Secondary, and Tertiary Alcohols
Authors: Mullens J. , Hanssens I. , Huyskens P.
Published: September 2010

Different association‐parameters of primary, secondary, and tertiary alcohols dissolved in CCl4 and C6H6 were compared with their values in cyclohexane. The parameters are the monomer‐fraction α1, the fraction of the open entities relatively to the formal number of molecules σαn, o, the average degree of association of one molecule σnw, the fraction of the number of all the real entities relatively to the formal number of molecules σαn and the mean association‐constants kM of a monomer to a given entity (monomer, dimer…).

The experimental methods were the determination of the partition‐coefficients of the alcohols between the organic solvent and water and the infra‐red spectrometry. This study shows that the concurrence the solvents CCl4 and C6H5 oppose to the auto‐association of the alcohols is not the same for all the alcohols. These differences in solvent‐effects lead in some cases to an inversion in the sequence of the alcohols ordered after their association‐parameters in benzene and in CCl4 relatively to this sequence in C6H12.
Ring Contraction In 1,3‐Dioxanes
Authors: Borremans F. , Anteunis M.
Published: September 2010

Ring contraction is observed during nucleophilic displacement reactions of 5‐hydroxy‐2‐methyl‐1,3‐dioxanes.

Evidence is put forward that the mechanism of this contraction is not similar to that of the concerted ring contractions known for analogous pyrane‐ and/or 1,3‐dithiane systems.

A reaction path concordant with experimental facts is advanced.
Preparation of 4,6‐Methyl, Alkyl‐1,3‐Diselenanes; 4,6‐Methyl, Alkyl‐1,3‐Thiaselenanes and 4,6‐Methyl, Alkyl‐Oxaselenanes
Authors: Geens A. , Anteunis M.
Published: September 2010

A general method for the preparation of 4,6‐disubstituted 1,3‐diselenanes and corresponding thiaselenanes and oxaselenanes is reported starting from appropriate (secondary) β‐diols. The corresponding mono‐ or di‐mesylates (alt. β‐dibromides) are treated with sodium selenocyanate and/or sodium sulfocyanate in HMPT below 80°C. The resulting alkyl β‐(di)seleno(sulfo) cyanates are subsequently reduced with sodium in liquid ammonia, followed by formalation in strong acidic medium. The resulting different positional and geometric isomers could not be completely separated by GC. Small amounts of accompanying 1,2‐diselenolanes may disturb class‐separation, but they can be removed after LAH treatment of the reaction mixture.
Hétérocycles Tellures. II. La Telluroflavanone
Authors: Piette J.‐L. , Renson M.
Published: September 2010

L'o‐méthyltelluroacétophénone est préparée par réaction du lithium sur l'(o‐iodo phényl)‐2 méthyl‐2 dioxolane‐1,3, suivie successivement de la condensation avec le tellure et l'Iodure de méthyle.

La condensation de cette substance avec le benzaldéhyde conduit au (cinnamoyl‐2 phényl) méthyltellurure qui peut être cyclisé en telluroflavanone. Le produit principal de la réaction est cependant le (cinnamoyl‐2 phényl) bromure de tellurényle.
The Isomerization Mechanism of Humulone
Authors: Verzele M. , van Boven M.
Published: September 2010

The first step in the isomerization of humulone in mildly acid or alkaline media is the formation of a mono anion. This is followed by stereospecific ketonization and only then by the ring contraction, producing trans and cis isohumulone, in a 32/68 ratio. In strong alkaline medium the reaction proceeds over a dianion form and the isomer ratio is then 50/50.
Oxygen‐inhibited photochlorination of 1,2‐dichloroethane
Authors: Bertrand L. , Bizongwako J. , Huybrechts G. , Olbregts J.
Published: September 2010

The oxygen‐inhibited photochlorination of 1,2‐dichloroethane has been studied in the gas‐phase between 321 and 489,5°K. The following rate constants have been estimated:

magnified image

These results are compared to those observed for the reactions of C2H6, C2HCl5, C2HCl3 and C2Cl4.
Sélénazolidines IV. Sélénazolidines Dérivées de la Séléno Cystéine et de la Sélénopenicillamine
Authors: Draguet C. , Renson M.
Published: September 2010

Nous décrivons la synthèse de quelques carboxy‐4 sélénazolidines, issues de la sélénocystéine et de la sélénopénicillamine.
Mechanism of the Iodide‐Ion Induced Dehalogenation of Substituted Stilbene Dibromides
Authors: Nasielski J. , Guiette‐Limbourg V.
Published: September 2010

Symmetrically ring‐substituted stilbene meso dibromides are dehalogenated by iodide ions in acetone with rates depending on the substituent. The HAMMETT pσ correlation for this E2 concerted elimination is however a curve showing a well‐defined minimum (fig. 1) rather than a straight line. This behaviour is ascribed to the very high polarizability of the transition state.
Radiation chemistry of 1‐chloropentane in the solid phase I. Influence of the dose
Authors: Ceulemans J. , Claes P.
Published: September 2010

The influence of the dose on the yields of the radiolysis products of 1‐chloropentane, irradiated in the solid phase by gamma rays of a 60Co source, has been investigated. We observed a decrease of the yield of hydrogen, hydrogen chloride, the pentenes, the decanes and of certain chlorodecanes and an increase of the yield of pentane and of certain dichloropentanes and dichlorodecanes in function of the dose. Some of these dose effects cannot be explained by a purely radicalar mechanism, but they may be explained by a mechanism, which includes radicalar and ionic reactions. It must therefore be concluded that ionic species play an important role in the radiolysis of solid 1‐chloropentane. The effects, invoked to explain the influence of the dose on the G yields, are reactions of active species with unsaturates formed during the radiolysis or with trapped radicals.
Alcaloïdes Pipéridiniques III. Nouveaux Alcaloïdes du Prosopis Africana (Guill. et Perr.) Taub.: Isoprosopinines A et B, Prosophylline, Prosafrine Et Prosafrinine [1]
Authors: Khuong‐Huu Qui , Ratle Georges , Monseur Xavier , Goutarel Robert
Published: September 2010

The structures of five new alkaloids have been established: the isoprosopinines A and B, 1 and 2 are homogeneous mixture: isoprosopinine A is (2R, 3S, 6R) 2‐hydroxymethyl 3‐hydroxy 6‐dodecyl 7°‐keto piperidine and isoprosopinine B is (2R, 3S, 6R) 2‐hydroxymethyl 3‐hydroxy 6‐dodecyl 8°‐keto piperidine.

Prosophylline 4 is d 2‐hydroxymethyl 3‐hydroxyl 6‐dodecyl 10°‐keto piperidine, prosafrine 9 is (2R, 3R, 6S) 2‐methyl 3‐hydroxy 6‐dodecyl 10°‐hydroxy piperidine and prosafrinine 11, is (2R, 3R, 6S) 2‐methyl 3‐hydroxy 6‐dodecyl 10°‐keto piperidine.
Étude de Complexes Accepteur‐Donneur par Spectrométrie Infrarouge III. Influence de la Nature du Solvant sur les Complexes Formés Entre L'Acétophénone ET SbCl3 (suite)
Authors: Ère‐Zur Nedden G. Lecl
Published: September 2010

Infrared intensity measurements of the free C = 0 band have been used to investigate the complex formation between antimony trichloride and acetophenone in carbon disulfide, benzene and trichlorethylene. The dissociation constants of the acceptor‐donor complexes with a 1:1 stoichiometry are compared with different parameters of the solvents.
Constituents of Peppers II. Piperinic Acid and its Isomers
Authors: Cleyn R. De , Verzele A.
Published: September 2010

The four isomers piperinic, chavicinic, isopiperinic and isochavicinic acid are obtained by irradiation at λ = 350 nm of a methanolic solution of piperinic acid. They are separated by counter current distribution. Their spectral characteristics are discussed.
Structure Cristalline de la 4‐Nitro‐4′‐Méthoxy‐N‐Benzylidène‐Aniline
Authors: Meunier‐Piret J. , Piret P. , Germain G. , Meerssche M. Van
Published: September 2010

The crystal structure of 4‐nitro‐4′‐methoxy‐benzalaniline has been determined by X‐ray diffraction. Space group P21/c, a =12.888, b = 7.098, c= 14.066 Å, β = 102.820°; Z = 4. Distance N = C: 1.235 Å, angles NCC and CNC: 124° and 117°. Angle between the mean planes of the phenyl groups: 52.5°
Isomérie Anneau‐Chaïne Ouverte. Obtention de la Diphényl‐2,2 Benzoxathianne‐1,3 One‐4
Authors: Renson M.
Published: September 2010

L'action du diphénylcadmium sur le chlorure de benzoylthiosalicyloyle donne la diphényl‐2,2 benzoxathianne‐1,3 one‐4. Nous avons préparé cette substance par une seconde méthode non ambiguë. Elle est identique à celle obtenue récemment par Dittmer et Whitman suivant une méthode totalement différente.
Essais de Chloration Dirigée XVII. Photochlorations D'Acétates et de Chlorures D'alkyles en Compétition Avec le Toluène[1]
Authors: Soumillion J. Ph. , Bruylants A. , De Wolf B. , Cuvelier B.
Published: September 2010

Photochlorinations of alkyl acetates (R‐OCOCH3 with R = n‐propyl, n‐butyl, n‐amyl, i‐butyle) and chloroalcanes (R‐Cl with R = n‐amyl, n‐hexyl) were performed in competition with toluene.

With the aid of properly modified TAFT's equation, the relative reactivities of hydrogen atoms were correlated with substituent effects (inductive and mesomeric effects, hyperconjugation).

The authors observed an inversion in the order of reactivities on the terminal positions of 1‐chlorohexane. They attributed this phenomenon to the aliphatic chain's crumpling of the molecule, They also discuss the problem of the transmission of inductive effects across the aliphatic chain of the molecules.
Amino Steroids ‐ Conanine and Heteroconanine Derivatives
Authors: van De Woude G. , van Hove L.
Published: September 2010

Conanine (IIh) and heteroconanine (IIIh) were obtained as the ultimate products of two reaction sequences starting from 3β‐hydroxy‐Sα.‐pregnan‐20‐one oxime and involving the preparation of epimeric 20‐amino steroids.

Comparison of physical properties of these epimer pairs shows that at least qualitative effects can be correlated with the configuration at C‐20 of epimer 20‐amino steroids.
Tautomérie Dans la Série des Pyrazolinones. III. Influence de la Position et de la Nature des Substituants sur L'Équilibre Prototropique des Pyrazoline‐5‐ones N1 Substituées
Authors: Maquestiau A. , van Haverbeke Y. , Jacquerye R.
Published: September 2010

The influence of substituents on N1 substituted pyrazolin‐5‐ones on tautomeric equilibrium has been carried out.

In position 4, the isomer CH is strongly displaced towards NH and equilibrium is shifted by electrowithdrawing substituents to the pyrazol‐5‐ol form.

An explanation for concentration effect observed in a series of pyrazolinone molecules is proposed.
Mesure Du Potentiel Standard Du Couple Pu(IV)/Pu(III) Dans L'eutectique LiCl‐KCl Entre 400 Et 500°C
Authors: Martinot L.
Published: September 2010

We have measured the standard potential of the system Pu(IV)/Pu(III) in a LiCl‐KCl molten eutectic.

The cell used was the following one: magnified image A comparison with previous standard potential determinations of uranium and neptunium in the same eutectic is reported.
N‐alkylation of 1, 4‐dihydropyridine derivatives
Authors: Dommisse R. A. , Alderweireldt F. C.
Published: September 2010

A series of 1‐alkyl‐2, 6‐dimethyl‐3, 5‐diethoxycarbonyl‐4‐aryl‐1, 4‐dihydropyridines have been synthesised by the reaction of the corresponding 1, 4‐dihydro‐pyridines with consecutively sodium hydride and alkyl halides.
Formal Properties of Stereoisomerizations of Pentacoordinate Complexes. II. Particular Ligand Partitions
Authors: Brocas J. , Willem R.
Published: September 2010

In this paper, we present the solution of the rate equation of all the possible isomerization modes of a trigonal bipyramidal pentacoordinate complex in which less than five ligands are different. The possible applications of this model are discussed.
The Role of Charge‐Transfer Complexes in the Reaction of Tertiary Amines with Tetrachlorophthalic Anhydride
Authors: Nagy J. B. , Nagy O. B. , Bruylants A.
Published: September 2010

Tetrachlorophthalic anhydride reacts readily with tertiary amines in non‐hydroxylic organic media to give a highly hygroscopic betaïne‐like product formed by the opening of the anhydride ring. The structure of this product is proven by U. V., I. R. and N. M. R. data. The n‐π charge‐transfer complexes formed between the anhydride and the amines are detected.

The solvent effect study suggests that these charge‐transfer complexes might be real intermediates on the reaction path.

In the light of the results obtained a general scheme is proposed for nucleophilic reactions of the carbonyl, group. A solvent parameter is also proposed to represent the π‐donor ability of aromatic molecules.
Acrylamidines and Polyacrylamidines. Part 2. A New Synthesis of N‐Substituted Acrylamidines
Authors: Fuks R.
Published: September 2010

N‐substituted acrylamidines, a new class of acrylic monomers have been obtained recently(1) from acrylonitrile, an alkyl halide, a Lewis acid and an amine.

I would like to report on a new synthesis starting from β‐chloropropionitrile 1 following the general method previously published(2).

The N‐alkylation of 1 with isopropyl chloride in the presence of ferric chloride gives N‐isopropyl‐β‐chloropropionitrilium tetrachloroferrat 2. Its aminolysis with aniline provides the amidinium salt 3 whose neutralization furnishes the N‐isopropyl‐N′‐phenyl‐β‐chloropropionamidine 4. This rearranges on standing at room temperature within an hour or two into the hydrochloride of N‐isopropyl‐N′‐phenylacrylamidine 5 identical with the compound prepared from acrylonitrile (1).
Conformational Aspects of Some Methoxysubstituted Hexacarbocyclic Derivatives
Authors: Anteunis M. , Geens A. , van Cauwenberghe And R.
Published: September 2010

The quantitative conformational behaviour of a methoxy group is studied in a series of hexacarbocyclic compounds I, II, III and VII depicted in SCHEME 1. It is found (Table I) that the equatorial preference of that group is accentuated in polar solvents such as freon 21, propably for entropy reasons. The conformational behaviour is normal for the spiro derivative II, but in the 2‐methoxy cis‐decalane a complex situation arises from additional no‐bond interactions in the decalane skeleton itself. Some derivatives in which the conformational behaviour of a hydroxy group could be weighted against that of a methoxy group were also investigated, and show results in accordance with expectations.

Finally the barrier for ring reversal between equienergetic conformer possessing various types of methoxy substitutions were studied by different methods (Table III). The unreliability in the calculation of ΔH∦ and ΔS∦ was noted.
Statistical Evaluation of Two Air Samplers and of The activation Analysis of Aerosols
Authors: Heindryckx R. , Dams R.
Published: September 2010

Using two types of high volume air sampling systems the reproducibility of the sampling procedure, the homogeneity of the collected aerosols over the filter and the standard deviation of the analyses are evaluated. Aerosols are collected simultaneously with 4 identical samplers on one location. The 4 filters are quartered and the concentrations of 11 elements are determined in triplicate on all 16 quarters by instrumental neutron activation analysis. A variance and a propagation of errors analysis are performed.
Kinetic Equations of Octahedral Complexes
Authors: Brocas J. , Fastenakel D. , Hicquebrand J. , Willera R.
Published: September 2010

The solution of the rate equations of the isomerization modes of octahedral hexacoordinate complexes is discussed for the general and all the particular ligand partitions. Possible applications of this model are presented.
Étude R. P. E. De La Recombinaison Des Radicaux Pièges Dans Quelques Solides Organiques Polymorphes Irradies A 77°k
Authors: Mauer D. , Tilquin B. , Claes P.
Published: September 2010

The recombination temperature (TR) of radicals trapped in σ‐irradiated organic solids showing phase transitions has been determined. A comparison is made between TR and the entropy of transition. It is concluded that radical diffusion is due to molecular reorganization during phase transition.
On The Occurrence of Fries Type Reactions in Polyphosphoric Acid. Synthesis of 2‐alkyl Substituted 4‐Chromanones from Phenols and α, β‐Unsaturated Carboxylic Acids
Authors: van De Sande C. , Vandewalle M.
Published: September 2010

The condensation of phenols and α, β‐unsaturated carboxylic acids in polyphosphoric acid is investigated. Spectroscopic data are included.
Structure Determination and Absolute Stereochemistry of The Bicyclic Diterpene Lithofellic Acid
Authors: Albert D. , Hootelé C. , Kaisin M.
Published: September 2010

The structure of lithofellic acid, main constituent of a bezoar, has been shown to be 3 (R) hydroxy enantio labdanolic acid I.
Les Nitrates Basiques Mixtes de Zinc et de Nickel
Authors: Mannoorettonnil M. , Glibert J.
Published: September 2010

The basic nitrates of zinc and nickel precipitated at 20°C have the compositions Zn5(OH)8(NO3)2·2 H2O and 4 Ni(OH)2·Ni(OH)0,75 (NO3)I, 25·n H2O· Obtention of this monoclinic zinc salt is preceeded by the formation of a double layered hexagonal compound. At 75°C, ZnO and Ni(OH)2 are formed.

In mixed (Zn, Ni)‐solutions, at 20°C and for a reaction time of about I hour, the solid solution Zn5‐xNix (OH)8(NO3)2·2 H2 2O (I) is obtained in the zinc rich region. The passage to the monoclinic system is inhibited with the increase in the percentage of nickel, resulting in the precipitation of the double layered basic nitrate 4 ZnI‐x Nix (OH)2· Ni(NO3)2·n H2O (II) from 20 to 50 at. · Ni.

A transition zone separates this salt from the basic nitrate of nickel in which the maximum solubility of zinc is about 10% at.

At 75°C, ZnI‐xNixO (xmax· = 0, 4 at. %Ni) and NiI‐yZny(OH)2 (ymax · = 26 at. %Zn) are respectively formed. A demixtion zone separates the oxide from the double layered basic nitrate (II).
The photoproduction of dihydroxotetracyano‐cobaltate(III)
Authors: Viaene L. , D'Olieslager J. , De Jaegere S.
Published: September 2010

The photochemical substitution of CN− by OH− in Co(CN)5OH3‐ yields either cis‐ or trans‐ Co(CN)4 (OH)3‐2 depending on the temperature. At 25°C a quantum yield of 0.093 was calculated. The thermal anation of cis‐Co (CN)4 (OH)3‐2 with CN− was found to follow second order kinetics with a rate constant k2 = 1.2.10−2 l. mole−1 sec−1 at 25°C.
Addition of chlorine atom on vinyl chloride
Authors: Olbregts J.
Published: September 2010

The competitive photochlorination of vinyl chloride and ethane has been studied at 322°K and permits one to measure k2 = 1010 mole −11 sec −1 for the rate constant of the addition of a Cl atom on vinyl chloride. This value is compared with those obtained for other chlorinated ethylenes and is discussed with respect to recent theoretical calculations.
Organometallic Compounds. 40. Electron impact fragmentation of stannacycloalkanes
Authors: Gielen M. , Topart J.
Published: September 2010

The mass spectra of stannacyclopentanes, ‐hexanes and ‐heptanes are described and discussed.
Cyclopentanones. X A novel synthesis of (dl)‐prostaglandin F1α
Authors: De Clercq P. , Vandewalle M.
Published: September 2010

A novel total synthesis of (dl)‐prostaglandin F1α methyl ester is described. The 2,3‐dialkyl‐1,4‐cyclopentanediol system is obtained by the reduction of an appropriate 2,3‐dialkyl‐4‐hydroxy‐2‐cyclopentenone. The facile conversion of the most abundant isomeric cyclopentanediol, with the all trans relation of the four substituents to a δ‐lactone enables the creation of the required prostaglandin configuration and the construction of the C‐12 side chain. Extensive spectroscopic data are included.
Radiation Chemistry of Polycrystalline 1‐Chloropropane at 77 °K
Authors: De Jouge D. , Ceulemans J.
Published: September 2010

The radiation chemistry of polycrystalline 1‐chloropropane at 77°K has been studied, with special emphasis on the influence of the irradiation time. The most important dose effect is a very marked decrease of the yield of hexane as a function of the dose. The concentration of this product even passes through a maximum at high doses. A comparison is made with dose effects in glassy 1‐chloropentane; the most important differences are additional positive dose effects on certain dichloropentanes and dichlorodecanes in 1‐chloropentane. Two distinct processes appear to be responsible for dose effects in irradiated chloroalkanes at 77°K. The first is the reaction of mobile hydrogen atoms with neutral radicals, causing a decrease of the yield of these radicals in function of the dose. The second is charge transfer to radicals and olefins, which were formed in an earlier stage of the radiolysis. Both effects are present in glassy 1‐chloropentane but only the first does manifest itself in polycrystalline 1‐chloropropane. This may be due to a greater range of the secondary electrons or to better migration possibilities of chloride ions in glassy 1‐chloropentane than in polycrystalline 1‐chloropropane. In view of other experimental results, the last explanation seems to be the most plausible.
Determination of the Ash Content of Coal on the Basis of its Chemical Composition
Authors: Block C. , Dams R.
Published: September 2010

An attempt was made to calculate the ash content of Belgian coals, from the analytically determined concentrations of silicon and aluminium. Simultaneously the total oxygen content of the coals was determined. Silicon and oxygen were determined by 44 MeV neutron activation analysis; aluminium was determined by reactor neutron activation.

The precision of the ash content calculated on the basis of the silicon and aluminium concentration is generally better than respectively 8% and 12%. A precise estimation is not possible from the oxygen concentration. The validity of the method has been investigated for samples of different origin. The variations of the oxygen content are not correlated with the variations of the ash content. This is expected from the important contribution of organically bound oxygen.
Nuclear Magnetic Resonance Experiments on Multisulfur Heterocycles: 5‐Methyl‐1,2,3‐Trithiane
Authors: Anteunis M. , Goor G.
Published: September 2010

The aliphatic region in 5‐Me‐1,2,3‐trithiane takes, at least, an ideal chair and the ΔG‐value, found by low temperature 1H n. m. r., is 1.0 Kcal/mole
Comparative Carbon‐13 Nuclear Magnetic Resonance Study at 67.9 MHz on Lysozyme (Human and Egg‐White) and α‐Lactalbumin (Human and Bovine) in Their Native and Denatured State
Authors: Binst Georges Van , Biesemans Monique , Barel A. O.
Published: September 2010

A first detailed comparison of the 13C spectra at high field of two lysozymes (human and egg‐white) and two α‐lactalbumins (human and bovine milk) is presented. Assignments were made on most of the resonance peaks in the aliphatic and aromatic regions of the denatured proteins. The relative peak intensities clearly demonstrate the differences in the amino acid composition of the related proteins. The broadening and the complexity of the spectra of the native proteins reflect the non equivalence of the chemical groups in the folded conformation. The usefulness of 13C nmr spectroscopy in the study of the interaction between small molecules and proteins was tested on N‐acetylglucosamine in the presence of lysozyme.
Fragmentation D'Azoles Sous L'Impact Électronique. VIII. Isomérisation du benzoxazole et du 1, 2‐benzisoxazole avant dégradation
Authors: Maquestiau A. , van Haverbeke Y. , Flammang R. , Pierard J.
Published: September 2010

Benzoxazole and 1, 2‐benzisoxazole are isomerized in an o‐cyanophénol structure before degradation (losses of CO and HCN) as evidenced by analysis of metastable ions abundances and shapes.
Fragmentation D'Azoles Sous L'Impact Electronique. IX. Isomérisation du benzothiazole avant dégradation
Authors: Maquestiau A. , van Haverbeke Y. , Flammang R. , Pierard J.
Published: September 2010

The M‐HCN+. ion observed in the mass spectrum of benzothiazole is the result of two degradation processes:i) specific fragmentation of the heterocyclic part of the molecule and ii) isomerisation into an o‐mercaptobenzonitrile structure which eliminates HCN and CS. This latter process predominates for low‐energy molecular ions.
Effet De La Temperature Sur Les Rendements Des Produits Lourds Dans La Radiolyse Be L'hexane Normal Par Des Electrons Acceleres
Authors: Fontaine R. , Tilquin E. , Claes P.
Published: September 2010

Liquid hexane was irradiated by electrons at temperatures ranging from −60° to + 60°C. The influence of the irradiation temperature on the yields of octane, nonane, decane and dodecane was investigated. Relative yields of addition products containing secondary radical increase with temperature. This should be due to secondary hydrogen abstraction from the solvent by primary hexyl and fragment radicals at high temperature.
Solvent Extraction from Molten Salts. XII. Extraction OP Lutetium by Dialkylammonium Thiocyanates
Authors: David‐Auslaender J. , Zangen M. , Kertes A. S.
Published: September 2010

The partition of lutetium(III) between molten sodium‐potassium thiocyanate and chloronaphthalene solutions of dioctyl‐ and didodecylammonium thiocyanate has been determined radiometrically at 150°, 170° and 190°C. The log‐log plots of the distribution ratios versus the concentration of the alkylammonium salt extractants were found to deviate from linearity. The slopes vary between 1 and 2, being steeper for the extractant with the shorter hydrocarbon chain.

The data are interpreted in terms of anion exchange equilibria between the monomeric and the aggregated extractant and the anion Lu(SCN)−4
An Investigation of the Submicroanalysis of Metal Surfaces by Electrography and Carbon Filament Atomic Absorption Spectrometry
Authors: Shresta I. L. , West T. S.
Published: September 2010

A technique of ultramicro‐atomic absorption spectrometry on a carbon filament following electrographic sampling of the specimen is examined for the analysis of steel surfaces containing Cr, Cu, Mn and Ni in the range down to 0.2%. The matrix effect of the accompanying iron on the anodically dissolved minor elements is studied and simple separation techniques are devised on rapid precipitation of the bulk of the iron or solvent extraction of HFeCl4 to provide extra sensitivity for Cu, Mn or Ni where necessary. Sampling requires only 10 seconds and the entire analysis ± 6 minutes (16 if a separation is necessary). The precision is usually better than 10% but due to variations in sampling or inhomogeneity of the surface a few results may only be within 20% of the expected value. The procedure is recommended as a semi‐quantitative one.
Notiz über Diaddukte aus dem Benzylmercaptan und der Acetylendicarbonsäure Oder Ihrem Dimethylester
Authors: Larsson Erik
Published: September 2010

Es wird gezeigt, dass Benzylmercaptan in alkalischem Medium an Acetylendicarbonsäure und ihren Dimethylester unter Bildung von 2,3‐Di (benzylmercapto)‐bernsteinsäuren (oder Methylestern) angelagert wird.
Spectre de Vibration de Complexes a Transfert de Charge de ICN IV.—Perturbation du Spectre du Donneur d'Electrons
Authors: Leeuw J. Ve. , Zeegers‐Huyskens Th.
Published: September 2010

The infrared spectrum and in some cases, the Raman spectrum of some pyridine derivatives complexed with ICN are studied in solvents of low dielectric constants.

A number of vibrational frequencies and intensities of some pyridine derivatives (H, 4‐CH3, 2‐CH3, 3, 5‐diCH3, 2, 4, 6‐triCH3) is changed when the molecules are complexed with I‐CN. The a1, (or a) vibrations show the greatest perturbations. The modifications are discussed in terms of the charge transfer model proposed by Mulliken and Ferguson.
Molecular Force Field ‐ Some Octahedral XY6 Type Molecules and Ions
Authors: Thirugnanasambandam P. , Mohan S.
Published: September 2010

All the general quadratic valence force field force constants relating to Some octahedral XY6 type molecules and ions have been evaluated afresh using the Raman and infrared spectral frequencies and certain simplifying considerations from the study of kinetic constants and redundancy constraints by Wilson's F‐G matrix method.
Mobilité du Cation Sodium dans Une Série de Solvants Oxygènes
Authors: Detellier Christian , Laszlo Pierre
Published: September 2010

Le temps de corrélation caractéristique de la relaxation quadripolaire du sodium‐23 est obtenu à partir de la largeur de raie. II satisfait à la relation de Debye‐Stokes‐Einstein. Moyennant certaines hypothéses, on peut en déduire un rayon de Stokes de 3, 7 Å pour le cation sodium dans ces solvants.
Isomerization Modes and Longuet‐Higgins Groups
Authors: Fastenakel D. , Brocas J.
Published: September 2010

We analyze the relationship between two fundamental aspects of the study of molecular non‐rigidity: isomerization modes and Longuet‐Higgins groups. We introduce a new formulation of isomerization modes including permutationsinversion. We show how to use this new representation of isomerization modes for constructing Longuet‐Higgins groups, and we illustrate it on an example.
Adsorption of Hydrogen on Supported Metal Catalysts. Microgravimetric Measurements on Supported Rhodium, Platinum and Nickel
Authors: De Vijlder M. , Vanden Kerchove F.
Published: September 2010

A micro‐balance was used to compare the adsorption of hydrogen and deuterium on supported metal catalysts, which contained 50% weight percent of Rh, Pt or Ni. Reversible and irreversible adsorption are discerned.

The reversible adsorption is the same for hydrogen and deuterium and does not differ much for the three metals. Rhodium adsorbs somewhat more than nickel and platinum.

The irreversible adsorption is detected by exchanging the total amount of adsorbed gas by its isotope. For nickel and platinum the irreversible adsorption equals almost the reversible one but for rhodium the irreversible adsorption is by a factor 4 greater.

71% of all Rh atoms have bound a hydrogen atom; the percentage is 21% for Pt and 6% for Ni.

The dispersion of Rh must be very high, which gives a very high specific surface area of about 300 m2/g rhodium; for the two other metals this area is about 50 m2/g.
The Crystal and Molecular Structure of N,N‐Dimethyl‐Dithiooxamide
Authors: Christensen A. , Geise H. J. , van Der Veken B. J.
Published: September 2010

N,N‐dimethyl‐dithiooxamide (DMTO), (CH3)2NCS‐CSNH2 crystallizes in the monoclinic space group P. Cell dimensions at ca. ‐150°C are: a = 9.21 Å, b = 6.76 Å, c = 11.73 Å, β = 104.64 Å. The structure was solved using MULTAN and refined to R = 0.045. The two thiooxamide moieties are in two planes, the dihedral angle between them being 93.1°. The crystal structure confirms predictions of the molecular geometry based on UV, LR, Raman spectra and dipole moment measurements.
A Synthetic Route to Para Cyclopropylaniline
Authors: Breugelmans Micheline , Anteunis Marc J. O.
Published: September 2010

A convenient four‐step synthesis is described for p.‐c. propylaniline in an overall yield of 50%, starting from styrene.
Modification d'un spectromètre de masse à géométrie inversée et applications à l'étude de processus collisionnels
Authors: Maquestiau A. , van Haverbeke Y. , De Meyer C. , Flammang R. , Perlaux J.
Published: September 2010

The design of a collision chamber located between the magnetic and electric sectors of a reversed geometry mass spectrometer is described. The analytical and theoretical interests of this arrangement are discussed.
Evidence for the acyclic structure of the stable ϵ‐Fission product ions from α, β‐unsaturated aldehydes, ketones and methylesters
Authors: van De Sande C. C. , De Meyer C. , Maquestiau A.
Published: September 2010

Collision Induced Dissociation (CID) spectra indicate that the stable ϵ‐fission product ions (lifetimes > 10−5 sec) produced from α, β‐unsaturated aldehydes and methylketones do not have the widely accepted dihydropyrillium ion structure proposed by McLafferty, but are acyclic as predicted by Meyerson. For the corresponding ions in the mass spectra of α, β‐unsaturated methylesters, the actual structure could not be determined (lack of suitable precursors), although it is shown that they certainly do not have dihydropyrillium ion structure. The stable (M‐H)+ ions from dihydropyrane are acyclic.
Mechanisms of substitution reactions of pentacyanoaquocobaltate (III)
Authors: Viaene L. , D'Olieslager J. , De Jaegere S.
Published: September 2010

The thermal and the photochemical reactions of Co(CN)5H2O2‐ with azide, iodide, hydroazoic acid and hydrocyanic acid are investigated. Data on the photochemical aquation of Co(CN)3−6 as a function of the chemical properties of the medium are also reported. On the basis of these kinetic data a reaction mechanism is proposed which takes into account the important role of the solvent cage surrounding the reacting complex.
Contribution à l'étude theorique de la liaison hydrogène I. Les dimères de l'eau
Authors: Leroy G. , Louterman‐Leloup G. , Ruelle P.
Published: September 2010

Dans ce travail, nous tentons d'expliquer l'existence et la nature des complexes intermoléculaires par liaison hydrogéne grâce au programme ab initio GAUSSIAN‐70 utilisé avec la base STO‐3G. Nous avons calculé les propriétés du dimère de l'eau. Lea résultats obtenus pour les trois structures possibles de ce système confirment que la plus stable correspond à l'enchaînement linéaire O…H‐0, où la distance intermoléculaire O…H est la plus courte (1.75 Å); l'approche des deux molécules s'effectue selon l'axe passant par l'un des centroïdes de charge de l'oxygène accepteur d'hydrogène avec un transfert de charge vers le système donneur de proton.
Structure de l'ester méthylique de l'acide 2,3‐diméthyl‐2‐phényl‐4 tosyloxybutyrique
Authors: Declercq J. P. , Germain G. , van Meerssche M. , Debaerdemaeker T.
Published: September 2010

The structure of the title compound has been determined in order to observe the relative configuration around the two asymmetric carbon atoms. Crystal data are a=19.148, b=8.446, c=6.180 Å; α=95.39, β=97.49, γ=100.56°; triclinic Pl Z=2[C20H24O5S]. The structure has been solved by Multan and refined by least squares to R=5,2%. Bond lengths and angles are normal.
Properties and reactions of 1,3‐oxathiolans — V. Conformational energy of an axial 2‐t‐butyl group. An attempt to determine epimer equilibria by microcalorimetry
Authors: Pihlaja K. , Keskinen R. , Nikkilä A.
Published: September 2010

Chemical equilibration of epimeric 2‐t‐butyl‐5‐methyl‐1, 3‐oxathiolans led to ‐ΔHo=4.60±0.05 kJ mol−1 and ‐ΔSo=2.9±0.16 J mol−1K−1 for the trans cis equilibrium. From them and the values of 1H vicinal coupling constants the conformational energy of a ψ‐axial 2‐t‐butyl group was estimated at 8.6±1.3 kJ mol−1. A microcalorimetric determination of the enthalpy difference for the epimer equilibrium resulted in a less accurate value of 4.5±1.0 kJ mol−1 and pointed out some disadvantages connected with the latter method.
Production de Molécules Excitées par Oxydation de Metaux Refractaires
Authors: Forier R. P. , Hiernaut J. P. , van Cakenberghe J.
Published: September 2010

La réaction d'oxydation de métaux réfractaires à haute température (1000‐2500° C) et basse pression (10−2‐ 10 torr) produit des oxydes volatils. Ceux‐ci peuvent se condenser sur une cible qui est la cathode d'une lentille électrostatique suivie d'un multiplicateur d'électrons secondaires. Durant la condensation, il apparait une émission électronique. L'intensité de cette émission est une fonction de la température du filament et de la pression d'oxygène dans le réacteur.
1H‐NMR study of 2,3,4,6,3′,4′‐hexa‐o‐acetyl‐1′,6′‐diacetamido‐1′,6′‐dideoxy sucrose at 300 MHZ
Authors: De Bruyn André , Anteunis Marc , Suami Tetsuo
Published: September 2010

The1H‐NMR parameters of the title compound (1) have been obtained for D2O and benzene/acetone solutions. The conformations of the rings and around the C(5′)‐C(6′) fragment of the β‐D‐fructofuranosyl part are discussed. The furanose moiety behaves differently from that in sucrose octaacetate itself.
Cyclopentanones. XVII: Prostaglandin synthesis involving the lithium‐liquid ammonia reduction of 3‐alkyl‐4‐hydroxy‐2‐(1′‐octynyl)‐2‐cyclopentenones
Authors: De Clercq P. , De Smet M. , Legein K. , Vanhulle F. , Vandewalle M.
Published: September 2010

The present paper describes the lithium‐liquid ammonia reduction of 3‐alkyl‐4‐hydroxy‐2‐(1′‐octynyl)‐2‐cyclopentenones; depending on the nature of the 3‐alkyl side chain prostaglandins of the F1‐series or primary prostaglandins of the 2‐series are synthesised.
Interaction of 1‐anilinonaphthalene‐8‐sulphonate (ANS) with egg‐white lysozyme and bovine α‐lactalbumin. Fluorescence study
Authors: Versee V. , Barel A. O.
Published: September 2010

Fluorescence titrations indicate that both proteins bind approximately one mol of ANS per mol of protein. The dissociation constant of the protein‐dye complex was 0.3 mM for lysozyme and 0.2 mM for α‐lactalbumin, indicating a moderate binding of the dye to either protein.

The results support the view that the enhancement of fluorescence of this dye in presence of both proteins is primarly caused by an environment of decreased polarity.

The fluorescence of the lysozyme‐ANS and α‐lactalbumin‐ANS complexes was not diminished by the presence of salts (KCl and K2SO4). From these last results it is suggested that ionic interactions do not play a significant role in binding.

Considering the fluorescence properties of the α‐lactalbumin‐dye complex, it was found that the binding site on α‐lactalbumin was more hydrophobic than that on lysozyme.