bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetical Study of Hydrocarbon‐Nitrous Oxide Flames
Authors: D'Olieslager J. , van Tiggelen A.
Published: September 2010

A comparative kinetical study of flames burning in mixtures of nitrous‐oxide and different hydrocarbons has been made. It has been found that the mean molecular weight of the chain carriers changes with the nature of the fuel. A probable reaction mechanism requests the formation of alkoxy radicals which decompose more or less easily according to their structure. Concerning the apparent activation energy derived from burning velocities at different degrees of dilution with nitrogen, no systematic change with the nature of the fuel has been observed.
Étude Cinétique de L'Hydrolyse des Amides X. Hydrolyse acide des Diamides
Authors: Vigneron‐Voortman Mme , Crooy P. , Bruylants A.
Published: September 2010

En milieu acide, l'hydrolyse d'une diamide comprend deux étapes consécutives compétitives: la transformation en acide amique (VI) et l'hydrolyse de celui‐ci en diacide (VII). Le dernier phénomène est complexe. II comprend une réaction apparemment non catalysée et une autre catalysée par l'acide minéral. On a observé, en effet, les deux relations cinétiques suivantes.

VI=k[diamide] [H3O+]

VII= (k+k[H3O+]) [diamide]

A 65° C, les paramètres cinétiques qui ont été déterminés dans ce travail sont les suivants:

acide oxamique

k= 1,22 . 10−5s−1; ΔH≠= 16,2 Kcal . m−1; ΔS≠= − 35,3u.e.s.

acide malonamique

k= 6,31 . 10−6s−1; ΔH≠= 18,2 Kcal . m−1; ΔS≠= − 30,7u.e.s.

maléamide

k= 1,1 . 10−41.m−1s−1; ΔH≠= 21,5 Kcal . m−1; ΔS≠= − 15,1u.e.s.

acide maléamique

k= 2,4 . 10−3s−1; ΔH≠= 19,6 Kcal . m−1; ΔS≠= −21,2u.e.s.

k= 8,5 . 10−41.m−1s−1; ΔH≠= 18,1 Kcal . m−1; ΔS≠= − 21,2u.e.s.

fumaramide

k= 9,5 . 10−51.m−1s−1; ΔH≠= 16,6 Kcal . m−1; ΔS≠= − 31,8u.e.s.

acide fumaramique

k= 0; il n' pas été possible de réaliser l'hydrolyse en l'absence de catalyseur.

k= 5,7 . 10−51.m−1s−1; ΔH≠= 12,3 Kcal . m−1; ΔS≠= − 43,7u.e.s.
Étude Théorique de Molécules Conjuguées II. Structure électronique et propriétés énergétiques de trois colorants polyméthiniques
Authors: Leroy G. , Nys J.
Published: September 2010

The electronic structure and some energetic properties of one cyanine and two azacyanines are calculated by the method described in paper I of this series. The results of these calculations are discussed in the light of available experimental data.
N.M.R. Experiments on Ketals III. P.M.R. Spectrum and conformations of the glycolketal of 1,2‐propanediol with acetone and acetaldehyde
Authors: Anteunis M. , Alderweireldt F.
Published: September 2010

The P.M.R. spectra of 2,2,4‐trimethyl‐1,3‐dioxolane and both cis and trans 2,4‐dimethyl‐1,3‐dioxolane are qualitatively analysed. The magnetic anisotropy of a methylgroup causes an upfield shift of the cis‐γ protons of about 0,15 ppm, and an analogous shift of 0,05 ppm for the cis‐γ methyl resonance. This can be used for structure elucidation.

In the acetonide and the cis‐compound (III) long range coupling between HA and 4‐CH3 (see II and III) is observed, while in the trans compound (II) it is not.
The Humulinic Acids IV. Humulinic acids C, D.
Authors: Anteunis M. , Bracke M. , Alderweireldt F. , Verzele M.
Published: September 2010

Humulinic acids C and D have respectively stucture III and IV. The methyl derivative of HAD(2) has structure V. The assignments are based on physical and chemical evidence. A mechanism for the formation of these substances is advanced.

The preparation and isolation of a number of humulinic acid isomers or derivatives called humulinic acids A, B, C, D (HAA, HAB, HAC, HAD) was reported by us before (2). The structure elucidation of humulinic acids A and B showing them to be trans and cis isomers I and II was also reported by our laboratory (1). The recent structure attribution to humulinic acid C by English authors (3) prompts us now to publish our further results.
The isomerization products of humulone
Authors: Alderweireldt F. , Verzele M. , Anteunis M. , Dierckens J.
Published: September 2010

The substance known as “isohumulone” is in fact a mixture of four components. They were separated by C.C.D. According to a new nomenclature based mainly on the chemically related humulinic acids A,B, C etc. series they are the stereoisomers isohumulone A and B (IV and V) and alloisohumulone A and B (VI and VII).
Hydrogenation. II. Mechanism of the catalytic reduction of ketones (and enol derivatives) in alcoholic acid solution
Authors: Acke M. , Anteunis M.
Published: September 2010

A mechanism is proposed for the formation of ethers and alkanes by the alcoholic acidic reduction of ketones with Adam's catalyst. An enol precursor for the alcohol formation seems logical, while enol, enolether and a half hydrogenated carbonium ion (HHC) also play a role in the formation of ethers and alkanes, as depicted in chart II.
Effets Électroniques dans les Systèmes Hétérocycliques Aromatiques Spectres de Résonance Magnétique Nucléaire de Pyridazines, Pyrimidines et S‐Triazines Substituées
Authors: Declerck F. , Degroote R. , De Lannoy J. , Nasielski‐Hinkens R. , Nasielski J.
Published: September 2010

Substituted pyridazines, pyrimidines and s‐triazines yield very simple N.M.R. spectra. Substituent effects of electron releasing groups are enhanced in these heterocycles, and surprisingly large shifts occur at the meta positions. The J4–5 in 3,6‐disubstituted pyridazines vary with the electron releasing ability of the substituent located at position 6 and are shown to parallel the bond index P4–5. Nitrogen quadrupole relaxation broadens the signal of 2‐Hydrogen in pyrimidine, whereas the s‐triazine protons yield sharp lines.
Synthèse des Oxo‐2‐Oxathiadiazoles‐L, 2, 3, 5
Authors: Eloy F. , Lenaers R.
Published: September 2010

Derivatives of 2‐oxo‐1, 2, 3, 5‐oxathiadiazole, are synthesized by the dipolar addition of sulfinylamines to nitrile oxides. They are also formed by treating a N‐substituted amidoxime with thionyl chloride in pyridine.
Recherches dans la Serie des Benzofurannes. XIV. Spectres Infra‐Rouges D'Alcoyl‐2 Benzofurannes
Authors: Binon F. , Goldenberg C.
Published: September 2010

The infra‐red spectral study of the γ C  H, γ C  C and δ C  H vibrations of 2‐alkyl benzofurans and of certain of the 3‐substituted derivatives of the latter has enabled specific frequencies of these compounds to be determined as well as criteria indicative of a non‐substitution in the 3‐position of the benzofuran.

The results obtained furthermore demonstrate the particular character resulting, for the C2 = C3 double bond, from the presence of the oxygen in the furan moiety of the molecule.
Absolute raman intensities of symmetrical stretching modes in some molecules and ions from delta‐function model of chemical binding
Authors: Lippincott E. R. , Nagarajan G.
Published: September 2010

A delta‐function potential model is used to derive an analytical expression for the derivative of the mean molecular polarizability with respect to a change in the internuclear distance at the equilibrium configuration for symmetrical stretching modes in the ground electronic states of diatomic and polyatomic systems. The calculated polarizability derivatives are in reasonable agreement with the experimental ones derived from Raman intensities. Bond orders are calculated from experimental polarizability derivatives for various ionic systems and the results are discussed.
Oxydation du Sulfure de 2,2′ Dichlordiéthyle par L'Hypochlorite de Calcium
Authors: Vassart S. , Jadot R.
Published: September 2010

The oxidation of 2,2′‐dichlordiethylsulfide by calcium hypochlorite has been shown to proceed mainly along two ways: the first giving the sulfoxyde and stopping at this stage, the second producing the sulfone which is further transformed into calcium sulfate and carbon dioxyde.
The humulinic acids. V. Specific catalytic reductions methyl allohumulinic acid D.
Authors: Anteunis M. , Bracke M. , Lepoivre A. , Verzele M. , Alderweireldt F.
Published: September 2010

Methylallohumulinic acid D (I) was isolated after acid treatment of either humulinic A (HAA) or humulinic acid B (HAB). Some specific reductions on this and other humulinic acids are reported. Dihydromethylhumulinic acid D (IV) is described. A new route to dihydro‐HAB was developed.
Recherches dans la Série des Benzofurannes. XVI. Spectres Infra‐Rouges D'Esters de L'Acide Coumarylique
Authors: Goldenberg C. , Blnon F.
Published: September 2010

The infra‐red spectrum of the coumarilic acid esters showed two absorption peaks in the γ C=O region. By means of various experiments, it was possible to exclude as causes of this duplication of absorption, FERMI's resonance hypotheses and the existence of associations. The phenomenon observed may best be explained on the basis of rotational isomerism. Study of the spectra of both cyclic and acyclic derivatives showed that this rotational isomerism affects the link magnified image whose sequence is in fact present in the esters of coumarilic acid.
Mise au Point D'Une Synthèse du Chlorure D'Ortho Méthylsélénobenzoyle. Étude de son Comportement VIS‐A‐VIS des Dérivés Organocadmiques
Authors: Ruwet A. , Renson M.
Published: September 2010

Nous étudions la préparation en quantités importantes, des différents stades de la synthèse des ortho méthylsélénoacylophénones. Dans ce but, nous avons mis au point une méthode permettant d'obtenir les chlorures d'acides possédant une fonction sélénoéther arylaliphatique sans destruction de celle‐ci. Nous avons pu préparer ainsi le chlorure d'ortho méthylsélénobenzoyle, qu'on n'avait pas pu obtenir jusqu' à présent. Nous avons montré en outre que, contrairement à l'opinion généralement admise, les dérivés organocadmiques sont susceptibles de réagir sur les cétones les plus courantes, et que cette réaction est même particulièrement aisée avec le diméthylcadmium. Enfin, nous décrivons plusieurs modes d'obtention de l'ortho méthylsélénobenzaldéhyde, encore inconnu.
L'Étude des Décompositions thermiques par Spectrométrie de Masse. II. Nitrite d'éthyle
Authors: Collin J. E. , Delplace A.
Published: September 2010

The thermal decomposition of ethylnitrite, at pressures between 100 and 200 microns, has been investigated in a quartz reactor coupled to a TOF mass spectrometer. A general decomposition scheme is proposed and discussed. It is found that acetaldehyde and ethanol, as well as nitric oxide, are important products of the reaction. No free radicals could be detected with certainty. The activation energy of the decomposition of ethylnitrite, apparently homogeneous, is found to be 37.5 kcal/m, and is consistent with a first order reaction.
Synthèses dans la Série des Acides Pyridine‐Carboxy‐Sulfoniques et Pyridine Disulfoniques
Authors: Delarge J. , Lapiere C. L.
Published: September 2010

The authors have synthetised pyridin‐3‐carboxy‐2‐sulfonic acid (XII), pyridin‐2‐carboxy‐3‐sulfonic acid (IV) and pyridin‐2, 3‐disulfonic acid.

The reaction of Meerwein and al. has been applied for the first time in the pyridin series. Several original intermediates are described (X, XIV, XV, XVI, IV).
Méthode Spectrographique de Détection des Méthylènes Actifs et Synthèse de Quelques Dérivés Styriliques, Cyanostilbéniques et Cyanazométhiniques. X. Étude cinétique des Condensations Stilbéniques et Azométhiniques
Authors: Feytmans Medicis M. E. ‐De , Bruylants A.
Published: September 2010

Ce travail est consacré à la réaction de condensation des nitriles phényl‐acétiques avec lep‐diméthylaminobenzaldéhyde (réaction de Meyer‐Frost) et avec lap‐nitrosodiméthylaniline (réaction d'Ehrlich‐Sachs). L'étude a porté sur le nitrile phénylacétique et ses dérivés cyano‐4, cyano‐3, bromo‐4 et chloro‐4 phénylacétiques. Les deux réactions sont régies par la même cinétique formelle d'ordre trois. Les constantes de vitesse (ks) sont reliées à la nature de substituant (σ) par la relation de Hammett et les constantes de réaction, dans la série stilbénique (MF) et dans la série azométhinique (ES), sont ρMF(30°C) = +1,95 et ρES(30°C) = +3, 29. Le domaine de température exploré a permis la détermination des températures isocinétiques (β); on a trouvé βMF= 416°K et βES= 455° K. Une évaluation de l'acidité des nitriles phénylacétiques a permis de préciser, dans le mécanisme réactionnel, le rôle du carbanion en tant que nucléophile et de caractériser, pour les deux familles de réactions étudiées, les étapes limitatives comme étant des substitutions à nucléophiles variables [SN(PN)v] sur centre insaturé.
Indole Alkaloids XIII. The Structure of Jollyanine
Authors: Hootele C. , Levy R. , Kaisin M. , Pecher J. , Martin R. H.
Published: September 2010

Jollyanine, a minor alkaloid from Conopharyngia jollyana, is shown to have structure XI (R1 = OCH3).
Structure De La Di (Fer‐Tricarbonyle)‐Diphénylurée Fe2 (CO)6 (C6 H5 NCONC6 H5)
Authors: Piron Jacques , Piret Paul , Meerssche Maurice Van
Published: September 2010

Fe2C19N2O7H10, product of the reaction between Fe3(CO)12 and C6H5NCO, crystallizes in the space group P2i/c with four molecules in a unit cell of dimensions a = 8.54, b = 13.25, c = 19.49 Å, β = 106.6°. The crystal structure has been determined by three‐dimensional X‐ray diffraction methods (Weissenberg photographs, symbolic addition procedure, electron‐density maps, least‐squares refinement). The molecule is formed by association between C6H5‐N‐C(O)‐N‐C6H5 and (OC)3 Fe‐Fe(CO)3: each N atom of the first part is linked to the two Fe atoms of the second.
Étude Du Comportement Électrochimique Des Organo‐Magnésiens Dans Les Éthers Anhydres (2e partie)
Authors: Martinot L.
Published: September 2010

Afin d'élucider le mécanisme de l'oxydation électrochimique des organomagnésiens, on a appliqué plusieurs méthodes réservées jusqu'ici à la cinétique électrochimique en solution aqueuse.

La mesure du facteur de fréquence de la réaction lente ainsi que la détermination de l'ordre de la réaction indiquent que la particule électro‐active est un anion qui réagit selon un processus purement ionique.

La réaction cinétiquement déterminante consiste dans le transfert du premier électron de ľentité réactionnelle vers l'anode.
Ethanolysis of Ortho‐, Meta‐, and Parasubstituted Phenylacetyl Chlorides
Authors: Heidbuchel P. W.
Published: September 2010

The ethanolysis of substituted phenylacetyl chlorides was examined at 20°C in a binary solvent mixture of benzene and ethanol. The variation of the rate in the degenerated second order reaction was examined in function of the influence of the substituents. Quite a good Hammett relation was found for the meta‐ and parasubstituted derivatives (p = +0.160), while the ortho‐substituted ones have a low rate and don't follow this relation.
Preparation of Cytidine, Cytidylic Acids and Ribonucleic Acid Specifically Acetylated in the Exocyclic Amino Group of Cytosine
Authors: van Montagu M. , Molemans F. , Stockx J.
Published: September 2010

The synthesis and some properties are described of N(6)‐acetyl cytidine, the corresponding 3′‐, 5′‐, and cyclic 2′,3′‐phosphates and of RNA with N(6)‐acetylated cytosine groups.
Physico‐Chemical Properties of Acid Saponins Molecular Weight, Dissociation Constant, Micellar Aggregation in Solution
Authors: Vochten R. , Joos P. , Ruyssen R.
Published: September 2010

Het zuurequivalent van sapoalbine werd potentiometrisch bepaald als 1545. Bij een ionensterkte gelijk aan nul werd potentiometrisch een pKz = 3,52 afgeleid, terwijl de konduktometrische werkwijze voor een sapoalbine koncentratie van 0,080 g/l een pKz = 3,32 opleverde. De onderlinge afwijkingen tussen de konduktometrische resultaten zouden in verband staan met de veranderlijke aggregatietoestand van deze oplossingen. Aan de hand van een aantal technieken (oppervlaktespanning, geleidbaarheid, dissociatiekonstante, de snelheid waarmee het oppervlakte‐evenwicht zich instelt, polarografie, diffusie, solubilisatie van kleurstoffen, differentiaalrefraktometrie en turbidimetrie) werd aangetoond dat oplossingen van sapoalbine vanaf ±0.100g/l (7.10−5 mol/l) micellair zijn. Uit lichtverstrooiingsproeven werd een micelgewicht van 7.142 afgeleid, hetgeen benaderend overeenkomt met een aggregatiegetal van 5. Deze kleine micellen kan men als bolvormig veronderstellen. De straal van het gehydrateerd deeltje, berekend uit viskosimetrische resultaten, bedroeg 14,5 Å terwijl voor de dikte van de watermancel een waarde van 2 Å gevonden werd.
Structure Cristalline Du Chlorure De Lithium Dioxanne‐1,4 Monohydrate: LiCl.C4H8O2. H2O
Authors: Durant F. , Griffé M.
Published: September 2010

LiCl. C4H8O2. H2O crystallizes in the monoclinic system, space group P21/c with unit‐cell dimensions a = 5.98, b = 12.85, c = 10.49 Å, β = 113.67°, Z = 4. The structure has been determined from 1290 single‐crystal data by a three‐dimensional X‐ray analysis using heavy atom method, refined by Fourier synthesis and least‐squares method to an R index of 0.157. Each LiN+ is tetrahedrally surrounded by one Cl−, two O (dioxanne) and one O(H2O). The structure consists of infinite chains (Li+.C4H8O2)n and (Cl−. H2O)n parallel to the c crystallographic axis and held together by means of Li+‐O(H2O) and Li+‐Cl− bonds. The principal distances are Li‐Cl : 2.35, Li‐O : 1.90, 1.96, 1.97, O‐H…Cl : 3.15 and 3.19 Å. It is shown that a correlation exists between Li‐O distances and valence angles of the oxygen atoms. Mean distances in dioxanne : C‐O : 1.45, C‐C : 1.46 Å.
Un Disaccharide Nouveau Extrait De La Farine De Manioc II. Synthèses Du 5‐O‐α‐D‐Glucopyranosyl D‐Glucofuranose
Authors: Maghuin‐Rogister G.
Published: September 2010

Nous avons effectué la synthèse chimique du 5‐O‐α‐D‐glucopyranosyl D‐glucofuranose par deux voies différentes. Le composé synthétique possède les mêmes propriétés que le maniocose. Cet oligosaccharide était le seul disaccharide du D‐glucose non connu à ce jour.
Synthèse D'Amino‐3 Oxadiazoles‐1,2,4
Authors: Eloy F. , Deryckere A.
Published: September 2010

La réaction de l'hydroxylamine sur les N‐cyanoamidines fournit des mélanges d'oxadiazoles‐1,2,4 isomères aminés en positions 3 et 5. Les amino‐3 oxadiazoles sont prépondérants en série aromatique, tandis que les composé aminés en position 5 se forment surtout à partir des amidines aliphatiques. Le mécanisme des réactions est discuté.
Étude par R.M.N. de Haute Résolution de l'état Adsorbé. I. Mise en Évidence D'un Système Nucléaire Triphasé
Authors: Derouane Eric G.
Published: September 2010

Adsorbed systems were generally considered as composed of 2 distinct phases on the N.M.R. viewpoint. One phase corresponds to the first strongly perturbed monolayers, the other one being the liquid contained in the micro‐ and macropores of the support. We show that such an adsorbed system is in fact to be considered as composed of three N.M.R. phases wich correspond to the classical regions one distinguishes in classical studies of the adsorbed state; the first adsorbed monolayers, the compressed liquid in the micropores, and the unperturbed liquid in the macropores.

Linewidths variations as function of the amount adsorbed are explained and transverse relaxation times have been determined for each of these phases. They show an increasing molecular mobility as the number of adsorbed layers is increased.
N.M.R. Spectra of Dihydrostreptomycin and Some of its Degradation Products
Authors: Claes P. , Vanderhaeghe H. , Totté J. , Slinckx G.
Published: September 2010

The N.M.R. spectra of dihydrostreptomycin (I) sulfate, N‐methyldihydrostreptomycin (II) trihydrochloride, α‐ and β‐methyl dihydrostreptobiosaminide (VI and VII), and dideguanyldihydrostreptomycin (VIII) were taken in deuterium oxide. The J12 values of the anomeric protons of the dihydrostreptose and the L‐glucos‐amine fragment were in agreement with the α‐L configuration of the two glycosidic linkages of the streptomycin molecule proposed by McGilveray and Rinehart [2].
Étude par R.M.N. de Haute Résolution de L'état Adsorbé. IV. Influence de la Température Sur L'état de L'adsorbat dans les Micropores non Saturés
Authors: Derouane Eric G.
Published: September 2010

We have shown previously that adsorbed systems were to be considered as composed of three nuclear phases undergoing fast exchange between themselves (1). A careful examination of the linewidth dependence as a function of the amount of adsorbate showed that one was able to determine the molecular orientation in the satured micropores (II). In the present article we deal mainly with a quantitative discussion of the temperature effects on both the adsorbate state and adsorbate N.M.R. linewidth before micropore saturation. The capillary condensation model is used. It enables one to get a theoretical relation which expresses the linewidth corresponding to that sort of adsorbed system. The use of that relation permits the evaluation of incremental energies due to the interactions of the adsorbed molecules with the surface and between themselves. Adsorption energies are derived for the different adsorbates, and are found to be in close agreement with calorimetric values.
Synthesis of Thiosultones
Authors: Goethals E. J. , Huylebroeck J. , Smolders W.
Published: September 2010

Thiosultones (cyclic thiolsulfonates) have been prepared by two methods: oxidation of cyclic disulfides with hydrogen peroxide in acetic acid and reaction of the corresponding chlorosulfonyl chlorides with sodium sulfide in dry methanol.

Butanethiosultone and 4,4‐dimethylpropanethiosultone have been made using both methods, o.xylylenethiosultone using the first and propanethiosultone using the second method. The latter compound was unstable and polymerized upon standing. The other thiosultones were stable crystalline substances.
Theory on the Collapse Pressure of Mixed Insoluble Monolayers with Miscible Components
Authors: Joos P.
Published: September 2010

Using the chemical potential of each component in the surface and the bulk phases an equation was deduced, which allows to predict the collapse pressure of a mixed insoluble monolayer with miscible components, from the collapse pressure of each component separately. It was shown that the collapse of a mixed monolayer, is completely analogue to the distillation or crystallisation from a mixture. The equation deduced previously by Crisp is only of limited value. The present theory allows to investigate interaction at the interface. The theory was illustrated by a few systems cholesterol/cholanic acid, disteraoyllecithin/cholesterol, desoxycholic acid/tripalmitin and soybean lecithin/oleic acid.
Organometallic Compounds. X. P.M.R. Spectra of Tetrasubstituted Methyltin Derivatives: Steric Effects and the J(Sn–C–H) Coupling Constant
Authors: Gielen M. , De Clercq M. , Nasielski J.
Published: September 2010

A redistribution of s‐character in the tin orbitals of the Sn–C bonds of methyl‐substituted tetraorganotins R3SnR' are expected to depend on the steric requirements of the R and R' groups and might be held responsible for the differences found for the J(Sn–C–H) coupling constants.
Configuration Électronique des Catalyseurs D'époxydation
Authors: Rouchaud J. , Mingiedi F.
Published: September 2010

Propylene dissolved in benzene is oxidised by oxygen in the presence of catalytic amounts of chelates of heavy cations. The selectivity in epoxypropane induced by the catalyst is related to the structure of the ligand. The ratio selectivity in epoxypropane‐electronic structure of the ligand does not vary with the kind of the chelated cation. The peroxydic form of the catalyst being epoxidising, the same electronic configuration of the ligand induces the same capacity toward reversible epoxidation of the chelate.
Organometallic Compounds. XII. Topological Representations of Intramolecular Isomerizations of Five‐Coordinate Structures
Authors: Gielen M. , Nasielski J.
Published: September 2010

Topological representations are presented to describe the intramolecular isomerization paths in five‐coordinate trigonal bipyramids. The most general case, involving five different ligands is described by the graph of figure 2. It is shown how variations in the complexity in the ligand system are reflected in the corresponding graphs.
Theoretical Study of Small Ring Compounds. I. Cyclopropene and Cyclobutene
Authors: André J. M. , Cl. André M. , Leroy G.
Published: September 2010

In this work, we report an all‐electron SCF—LCAO—MO computation for the ground‐state wave functions of the cyclopropene and cyclobutene molecules. The study of the ethylenic bond shows some delocalization of π‐like electrons to the methylene groups. Experimental results are discussed.
Alcaloïdes peptidiques. IX[1] la canthiumine alcaloïde ducanthium euryoidesBull. (rubiacées)
Authors: Boulvin G. , Ottinger R. , Païs M. , Chiurdoglu G.
Published: September 2010

Un nouvel alcaloïde peptidique, la canthiumine1, a été isolé duCanthium EuryoidesBull. (Rubiacées). La nature des fragments qui le constituent —N,N‐diméthyl‐L‐phénylalanine,p‐hydroxy‐styrylamine, L‐proline et L‐thréo‐β‐phénylsérine — a été déterminée par hydrolyse acide de la dihydrocanthiumine2et par spectrométrie de masse. Le mode d'enchaînement de ces fragments est déduit du spectre de masse de la canthiumine.
NMR Experiments On Acetals. XIX. The NMR Analysis and Structure of 3‐Keto‐Lactose and β‐d‐Galactose
Authors: Anteunis M. , van Beeumen J. , De Bruyn A. , De Ley J.
Published: September 2010

The chemical structure of the glucoside‐ulose O‐β‐D‐xylo‐hexopyranosyl‐3‐ulose‐(1 → 4)‐D‐glucopyranoside (trivial name: 3‐keto‐lactose) is studied by nuclear magnetic resonance in deuterated dimethyl sulfoxide. The technique of multiple irradiation allows the identification of most of the signals in the spectrum (fig. 2). informative data are also obtained from the spectrum of β‐D‐galactopyranose (2) and methyl O‐β‐D‐ribohexopyranoside‐3‐ulose (3) (trivial name: methyl β‐3‐keto‐D‐glucopyranoside).

The lack of a free carbonyl function in 3‐keto‐lactose is due to the presence of the hemiacetal which is formed on crystallizing the compound from methanol. The hydroxyl group at the anomeric carbon atom has the β‐configuration (1). It is suggested that this ketosugar prevails dominantly as the hydrate when it is prepared from aqueous solutions.
Comportement Anormal Lors D'Une Réaction de Reformatsky. Obtention de Dérivés du Benzo(b) Thiophène et du Benzo(b) Sélénophène
Authors: Ruwet A. , Renson M.
Published: September 2010

Examination of the abnormal Reformatsky reaction on o‐methylthio and o‐methylselenoacetophenones shows the influence of SCH3 and SeCH3. When ethylbromacetate is used, the sulfur or selenium atoms are first attacked but ethyl α‐bromopropionate gives the desired cinnamic acids. Ethyl bromacetate leads to benzo(b)thiophene and benzo(b)selenophene compounds. When we first form the organozincic derivate, cinnamic acids are again obtained.
Formation de Chromones (O,S,Se) et D'Autres Dérivés par Action du Dicétène sur le Phénol, le Thiophénol et le Sélénophenol. Contribution â L'étude des Réactions de Pechmann et Simonis
Authors: Ruwet A. , Janne D. , Renson M.
Published: September 2010

The Pechmann and Simonis reactions are investigated with phenols (O, S, Se). Thio and selenophenols give thio‐1 and seleno‐1 chromones (Simonis reaction). Several cyclizing agents are studied. Ethyl acetylacetate is replaced by diketene. They give the Simonis reaction. From diketene we synthesize phenyl acetylthiol and selenolacetates which possess thiol or selenolester function. The cyclization produces rearrangement and leads to Simonis reaction. These 2 new ways give also chromones from oxygen compounds. We don't isolate thio‐1 and seleno‐1 coumarins. However, we obtain dimethyl‐2,6 phenylselenolcarboxylate‐3 γ‐pyrone which is yet converted to seleno‐1 chromone. We discuss all these results: the Pechmann and Simonis reactions intermediates are to be reconsidered, especially phenyl acetylacetates (O, S, Se).
Étude du Spectre ir des Thio‐1 et Séléno‐1 Coumarines et des Dérivés Thio‐2 Correspondants. Comparaison Avec les Thio‐1 et Séléno‐1 Chromones Isomères
Authors: Ruwet A. , Renson M.
Published: September 2010

Infrared spectra of coumarins (O, S, Se) and chromones (O, S, Se) in several solvents and of their complexes with Lewis‐acids are examined. The carbonyl band of thio‐1 and seleno‐1 coumarins is complex, abnormally low and not pure. A methyl group in position 3 gives important lowering of the CO. Infrared spectra of thio‐1 and seleno‐1 coumarins are very similar and constitute a rapid identification of isologous seleno‐1 coumarins. The thio‐1 and seleno‐1 chromones possess very different spectra, except the carbonyl region. There is doubt for the CS vibration because the formation of dithiocoumarins and thio‐2 seleno‐1 coumarins leads to 2 strong bands near 1000‐1150 cm−1. The CC is approached by comparison of coumarins (O, S, Se) with thio‐2 derivates. Interpretation of many results is possible by the hypothesis that a polar form occurs partly in thio‐1 and seleno‐1 coumarins, in dithiocoumarins and thio‐2 seleno‐1 coumarins, in thio‐1 and seleno‐1 chromones.
Synthèses de Telluroéthers Arylaliphatiques Substitués en Ortho par Différents Groupements Fonctionnels Carbonylés Préparation et Étude des Propriétés Chimiques de L'o‐méthyltellurobenzaldéhyde
Authors: Piette J. L. , Renson M.
Published: September 2010

La réaction entre l'o‐diéthoxyméthyl phényllithium et le tellure commercial a été appliquée avec succès à la préparation de l'o‐butyltellurobenzaldéhyde et de l'o‐méthyltellurobenzaldéhyde. À partir de cette dernière substance en particulier nous avons pu mettre au point les conditions de réaction de transformation du groupement aldéhyde de manière à obtenir pour la première fois des telluroéthers du type arylaliphatique substitués dans la position ortho par la plupart des groupements fonctionnels simples de la chimie organique.
Synthèse de Tétrahydrothiénopyridines
Authors: Eloy F. , Deryckere A.
Published: September 2010

Des tétrahydrothiénopyridines ont été obtenues par formylation réductive des thiénopyridines et par réduction par le borohydrure de sodium des sels quaternaires de thiénopyridinium.
Energy Level Diagrams of the “NiAs”‐, “Pyrite”‐ and “Spinel”‐Type Sulfides of Fe, Co and Ni
Authors: Pauwels L. J.
Published: September 2010

The crystallografic, magnetic and electrical data from literature, and results of own electrical resistivity measurements have been used to develop for the sulfides of Fe, Co and Ni, qualitative energy level diagrams, allowing a consistent interpretation of their properties. The development is made in terms of ligand‐field theory as well as band theory. The importance of covalent cation‐anion‐cation ** interaction is emphasized.
Free Energy, Enthalpy and Entropy Changes of the Ag (I) Complexes of Some ω‐Aminocarboxylic Acids
Authors: van Poucke L. C. , Thiers G. F. , Herman M. A. , Eeckhaut Z.
Published: September 2010

The acidity constants of the ω‐aminocarboxylic acids with n = 1,2,3,4,5 and the stability constants of the Ag(I) complexes of the corresponding aminocarboxylates were determined at 0°, 15° and 40°C in o.5 M KNO3. From this and the same data at 25°, reported previously, the free energy, enthalpy and entropy changes involved in complex formation were calculated using the temperature coefficient method. The same thermodynamic functions were also obtained from calorimetric data.
Hydroxy‐4 Thio‐1 et Séléno‐1 Coumarines voie Nouvelle de Synthèse
Authors: Ruwet A. , Draguet C. , Renson M.
Published: September 2010

Reaction of thio and selenophenols with malonic acids in polyphosphoric acid leads to 4‐hydroxy 1‐thio and 1‐seleno coumarines. This new synthesis is compared with other ways.
Étude par Diffraction‐X de Quelques Composés du Système Nicote Obtenus par Synthèse Thermique
Authors: de Meester de Betzembroeck P. , Naud J.
Published: September 2010

We have studied the compounds with metal/tellurium ratio less or equal to unity in the ternary system NiCoTe.

The limits of the homogeneity range of the hexagonal (Ni, Co)1–xTe phase have been fixed for different Ni/Co ratios.

The compounds formed in the series (NiλCo1–x)0,75 Te and (NixCo1–x)0,50 Te and their cristallographic parameters have been determined.
Propriétés Magnétiques et Schémas Électroniques des Séléniures et des Tellurures de Co et de Ni
Authors: Vandenbempt E. , Pauwels L. , de Clippeleir K.
Published: September 2010

L'étude de la susceptibilité magnétique en fonction de la température indique que les séléniures et tellurures de Co suivent la loi de Curie‐Weiss dans un grand domaine de température, tandis que les composés de Ni possèdent un comportement magnétique totalement différent: leur susceptibilité est quasi indépendante de la température (paramagnétisme de Pauli).

Par combinaison de nos résultats avec des données cristallographiques et électriques, nous avons déduit des schémas électroniques possibles pour ces composés.
NMR Experiments On Acetals. Part 30. Cyclopentanones VI≠. The Reaction Of 3‐Methyl‐1,2,4‐Cyclopentatrione With Ethylene Glycol A Case Of An A Typical Long‐Range Coupling
Authors: Anteunis M. , Vandewalle M. , van Wijnsberghe L.
Published: September 2010

Reaction of ethylene glycol with 1,2,4‐cyclopentatriones (and other pentacyclic α‐diketone systems) results in a mixture of two isomers: a bisdioxolane and the thermodynamically more stable tetraoxadecalane (naphtodioxane). In acidic conditions both systems may be interconverted. Chemical and PMR spectroscopic evidence for the structures is advanced. In one case the hydrolysis of a tetraoxadecalane system leads to a monodioxolane derivative of an α‐dione.

An anomalous long‐range PMR effect through four bonds (contraining sp2 hybrirds) is observed in the cyclopentanone moiety of 1,2‐bisethylenedioxy‐3‐methyl‐4‐cyclopentanone.
Study of the Kinetics, Intermediates and Product Distribution in the Synthesis and Decomposition Reactions of Thiourea Derivatives
Authors: Vanassche W. , Hoornaert G.
Published: September 2010

The solvent‐effect together with the influence of substituents in the aryl group on the yield of isothiocyanates in the decomposition of N‐mono aryl thioureas can partly be explained by solvent‐ and substituent‐effects on a consecutive reaction of two decomposition products amine and isothiocyanate. A more detailed investigation of this step, which is representative for the reaction scheme of thioureas, shows that reactions of aromatic amines with aryl isothiocyanates are characterized by an equilibrium limiting the yield of the product NN′ diaryl thiourea. Both amine and product seem to effect about equal catalytic influences on both steps of the equilibrium.

From a study of the solvent‐effect on the reaction rate, it can be concluded that besides the unspecific factors, polarity and polarisability, also association‐effects and catalytic activities of the solvent must be taken into account.

The considerable influence of the basicity of the amine on the reaction rate together with the pronounced effect of substituents in the phenyl isothiocyanate shows that the nucleophilic attack of the amine on the isothiocyanate must be the rate determining step; this view is in agreement with the low value for the isotope‐effect. The whole of the data can be correlated by assuming a reaction scheme wherein amine attacks the isothiocyanate both as a dimeric form and a monomeric form complexed with reaction product or solvent.
Conductivité électrique Du Picrate De N‐Butylammonium Dans Les Mélanges Eau Ou Alcool‐Dioxanne Et Nitrobenzène‐Benzène
Authors: Macau J. , Lamberts L.
Published: September 2010

The conductance of dilute solutions of n‐butylammonium picrate has been measured in water or ethanol‐dioxane mixtures and in nitrobenzene‐benzene mixtures. The data were analysed by the Fuoss conductance theory. The conductometric behavior of the salt in the different solvent mixtures has been discussed. The comparison suggests that solvation of the ions in hydrogen bonded solvents greatly lowers ion‐pairing. Points of the logarithm of the association constant against reciprocal dielectric constant lie on a straight line for the three solvent mixtures. The contact distance values obtained from the slopes are a σ 6 Å.
Attempted Synthesis of a Phosphaferrocene
Authors: Braye E. H. , Joshi K. K.
Published: September 2010

Potassium 2,3,4,5‐tetraphenylphosphol‐l‐ide (I) reacts with cyclopentadienyldicar‐bonyliron iodide yielding cyclopentadienyldicarbonyliron tetraphenylphosphol‐l‐ide (II), which could not be converted into a phosphaferrocene by thermal treatment.
The Influence of Oxygen on the Decomposition of Ammonium Persulfate
Authors: Liegeois J. M.
Published: September 2010

The decomposition of ammonium persulfate has been investigated in buffered solution with either purge of nitrogen, or saturation with oxygen. A decrease of the decomposition rate is observed when oxygen is forced to stay in the solution, the most pronounced in the second stage of the decomposition experiment. In the first stage, a higher rate of decomposition is observed which does not depend on the presence or not of oxygen. This can be due partly to the suppression by oxygen of an induced decomposition mechanism. The other part of the effect is explained by a reversible reaction of decomposition and a decomposition mechanism which involves the intervention of water. A kinetic equation is deduced which explains other results given in the literature.
Alcaloïdes Pipéridiniques II. Structures de la Prosopine et de la Prosopinine, Alcaloïdes du Prosopis Africana (Guill. et Perr.) Taub. [1]
Authors: Khuong‐Huu Qui , Ratle Georges , Monseur Xavier , Goutarel Robert
Published: September 2010

In a preliminary note [1] we established the plane structure of the prosopine 1,2‐hydroxymethyl 3‐hydroxy 6‐dodecyl 11°‐hydroxypiperidine and the prosopinine 8, 2‐hydroxymethyl 3‐hydroxy 6‐dodecyl 10°‐keto piperidine, alkaloids isolated from Prosopis africana (Guill & Perr) Taub.

This paper contains the study of the reduction products of the pyrrolidine 18b and the establishment of the relative and absolute configurations of these two alkaloids. The experimental part involves the details for the determination of these structures and also the extraction method of these two alkaloids as well as the new alkaloids: prosophylline, prosafrine and the prosafrinine isolated from leaves of P. africana and isoprosopinines A and B extracted from roots and stem bark of the same plant. The establishment of the structure of the new five alkaloids is the subject of the next paper.
Mechanism of Chlorite Oxidations Part I. Kinetics of the Oxidation of Formaldehyde by Chlorite Ion
Authors: Kudesia V. P.
Published: September 2010

The kinetics of oxidation of formaldehyde by chlorite ion in aqueous solution has been studied. The reaction is found to be of the first order with respect to formaldehyde and first order with respect to chlorite ion. Arrhenius equation is found to be valid for the reaction between 25° and 55°. The values of activation energy, ΔE≠; frequency factor, A; heat of activation, ΔH≠; entropy of activation, – ΔS≠ and free energy of activation, ΔG≠ (at 25°) are found to be 15.86 kcals/mole, 9.42 ± 107 l. mole−1 sec−1, 15.92 kcals/mole, 10.7 e. u. and 12.7 kcals/mole respectively.
La Déshydrohalogénation des Dérivés Halogènes de L'Éthylène. I. Étude Théorique Préliminaire par la Méthode CNDO
Authors: Leloup Geneviève , Leroy Georges
Published: September 2010

On étudie théoriquement les réactions de déshydrohalogénation des dérivés fluorés et chlorés de l'éthyléne par la méthode CNDO/2 de POPLE. Dans cette optique, on calcule les acidités thermodynamiques de ces composés ainsi que les chemins de réaction des éliminations cis et trans. L'analyse des résultats obtenus, grandeurs de structure et propriétés énergétiques, conduit à attribuer la préfférence trans à L'énergie d'activation de l'Elimination de l'halogène.
Formal Properties of Stereoisomerizations of Pentacoordinate Complexes. I. General Ligand Partition
Authors: Brocas J. , Willem R.
Published: September 2010

Trigonal bipyramidal complexes may undergo rearrangements without bondbreaking. We propose in this paper a model which describes the kinetic behaviour of the most general ligand partition [where all ligands are different) of the trigonal bipyramid. It unables us to derive the multiplication table of the rearrangement mode operators and to diagonalize them by the same linear transformation. Relaxation times and time evolutions are calculated for the five possible isomerization modes.
Potential Constants of Iodine Heptafluoride
Authors: Srinivasan G. J.
Published: September 2010

A most general harmonic potential energy function has been assumed for the pentagonal bipyramidal XY7 type of molecules belonging to the symmetry point group D5h and an attempt has been made to evaluate a complete set of potential constants of Iodine Heptafluoride by Wilson's F‐G matrix method and by making use of redundancy constraints obtained from the redundant symmetry coordinates.
Study of The Decomposition of Cyclobarbital (PhanodormR)
Authors: Willems G. , De Backer D. , Bouché R. , De Ranter C.
Published: September 2010

The cyclobarbital 2 (see formula fig 3) deteriorates when stored, due to a photochemical oxidation process. The components thus formed were separated by column chromatography and for the most important one, a structure determination was carried out. From NMR‐data the formation of 5‐(6‐oxo‐l‐cyclohexen‐1‐yl)‐5‐ethyl‐barbituric acid 1 (see formula fig 2) was concluded.
Oxidation products of hop bitter acids. Part VII. A further five‐membered ring product from the oxidation of colupulone
Authors: van Den Bossche R. , Anteunis M. , Verzele M.
Published: September 2010

Oxidation of colupulone (I) produces a complex mixture, separation of which by counter current distribution gives the spiro compound IV. Support for this structure comes mainly from 1H‐N. M. R. and mass spectral data.
NMR experiments on acetals. Part 48 the prins‐reaction on cyclic (poly) olefins and the characterization of resulting 1, 3‐dioxanes
Authors: Coryn M. , Anteunis Marc
Published: September 2010

We have investigated the Prins‐reaction of formaldehyde on several cyclic (poly) olefins. The nature (100 and 300 MHz NMR studies; table II) and yields of the resulting 1,3‐dioxanic compounds have been carefully assessed (Table I). The results indicate that most previous claims are to be taken only as general rules, with many exceptions however. Thus, a wide variety in stereospecificity of the primary reaction must be accepted, leading to syn and anti (diaxial) and even trans (diequatorial) addition routes. It seems acceptable that only protonated polymeric formaldehyde oligomers may rationalize such a broad spectrum of possibilities.
Application de la Spectrométrie de Masse en Serie Hétérocyclique. Système N‐Phenyl‐3,6‐Dihydro‐2H‐1,2‐Oxazine
Authors: Maquestiau A. , van Haverbeke Y. , Flammang R. , De Meyer C.
Published: September 2010

The behaviour of some N‐pheny 1‐3, 6‐dihydro‐2H‐ 1, 2‐oxazines is examined under electron impact. These compounds undergo essentially two competitive reactions : 1) a thermal elimination of water which leads to the corresponding N‐phenylpyrrole, as it is proved by the comparison of the metastable ratios evaluated on the oxazine‐H2O⌉·+fragment ions and on the N‐phenylpyrrole itself; 2) a retro Diels Alder fragmentation giving the nitrosobenzene and the butadienyl system.
The Separation and purification of ribofuranose derivates by countercurrent distribution
Authors: Vanbroeckhoven J. H. , Dierckens J. J. , Alderweireldt F. C.
Published: September 2010

This paper reports the purification and separation of several tri‐O‐benzoyl‐D‐ribofuranose derivates (2,3,4,5) by counter current distribution. A new product 1‐O‐Ethyl‐2,3,5‐tri‐benzoyl‐β‐D‐ribofuranose (5) has been isolated. The purity of all these products was tested by T. L. C. The N. M. R. spectra are discussed.
The anodic behaviour of lead in acid sulphate solutions. Influence of copper and cobalt ions
Authors: Ravindran Kanechamkandy , Heerman L. , van Simaeys L.
Published: September 2010

The anodic behaviour of lead has been studied at Pb/PbSO4 and PbSO4/PbO2 potentials in sulphuric acid solutions in presence of copper and cobalt ions by galvanostatic and potentiokinetic methods. The presence of cobalt ions has been observed to exert a beneficial effect in reducing the anodic dissolution of lead. Anodic corrosion products, in function of cations in solution, have been analyzed by X‐ ray diffraction technique. A schematic model of passivated lead anode in presence of cobalt ions has been proposed.
Réactions Chimiques de Composes de Neptunium Dans L'Eutectique LiCl‐KCl Fondu
Authors: Lysy R. , Landresse G. , Duyckaerts G.
Published: September 2010

Visible and near IR absorption spectrophotometry provides a good method for the study of chemical reactions in fused salts. It has been applied in the case of neptunium, whose chemical properties in a LiCl‐KCl eutectic between 400° and 600°C have been investigated.
Oxidation products of hop bitter acids. Part VIII. Six‐membered ring products from the oxidation of colupulone.
Authors: van Den Bossche R. , Anteunis M. , Borremans F. , Verzele M.
Published: September 2010

Air oxidation of colupulone in iso‐octane solution produces a complex mixture, separation of which by counter‐current distribution with the two phase system iso‐octane/buffer pH 6.40 gives the cyclohexa‐2,4,6‐trione epoxide (III).
Calcul De La Densité Des États Électroniques Des Polymères Stéréoréguliers. I. Procédé Par Échantillonnage
Authors: Delhalle J.
Published: September 2010

On décrit un programme de calcul de la densité des états électroniques des polymères stéréoréguliers par une technique d'échantillonnage. La somme équidistante est plus efficace que le procédé de Monte Carlo. Le programme est appliqué à l'étude du polyène régulier infini.
Conformation De L'Acide 3‐(Aminocarboxymethyl) 2‐Pyrrolidone 5‐Carboxylique
Authors: Welter A. , Marlier M. , Dardenne G.
Published: September 2010

A new naturally occuring amino acid, isolated from the seeds of Pentaclethra Macrophylle was found to be l the 3‐(Aminocarboxymethyl) 2‐Pyrrolidone 5‐Carboxylic acid.

The conformation of this amino acid in solution is determined from N. M. R. spectra and compared with the conformation in solid state.

The absolute configuration is established through a comparative study of the results obtained by O. R. D., C.D. spectroscopy and X‐ray diffraction.
Spectroscopic Intensity and Dipole Moment Study on Malononitriles
Authors: van Haverbeke L. , Herman M. A.
Published: September 2010

The Infrared and Raman intensities of the 2250 cm−1 band in malononitrile and some of its derivatives has been determined.

The dipole moments of these compounds have been measured in benzene solutions. The results are compared mutually and are discussed in terms of the inductive and electron delocalisation effects of the substituents.
Hydrolyse de l'acide 3(R)‐ [1′ (S) ‐ Aminocarboxymethyl] 2‐Pyrrolidone 5(S)‐Carboxylique
Authors: Welter A. , Jaddt J. , Dardenne G. , Marlier M. , Casimir J.
Published: September 2010

During the acid hydrolysis of the lactam linkage of the 3(R) ‐ [1′ (S)‐aminocarboxymethyl] 2‐pyrrolidone 5(S)‐carboxylic acid, three aminoacids were isolated. Their structure and absolute configuration are determinated.

Tha acid hydrolysis is found to proceed to an equilibrium between an open chain tricarboxylic di‐α aminoacid, a lactam aminoacid and two γ lactam amino acids as shown in fig. 3.
Mise en Evidence des Tautomeres Enethioliques des Mercaptopyridines en Spectrometrie de Masse
Authors: Maquestiau A. , van Haverbeke Y. , De Meyer C. , Katritzky A. R. , Frank J.
Published: September 2010

Equimolar mixtures of HS‐Py (Py=pyridine) and DS‐Py show primary isotope effects upon metastable ions for the CS loss. This is valid for the 3‐ and 4‐ isomers and this observation implies that thiol forms exist in the gaz phase. This result is also confirmed by the analogy in isotope effects between molecular ions of H(D)S‐Py and the daughter ones, generated by a four centered elimination of C2H4 and C2D4 respectively from Py‐S‐C2H5 and Py‐S‐C2D5. The insensibility of the CS loss following deuteriation of the 2‐isomer does not exclude the presence of the thiol tautomer: this phenomenon is explained by and ortho effect exerted by the pyridinic nitrogen.