bluuebunny/crossref_metadata_2025 huggingface dataset:
Alternative Syntheses of 3,3,5‐Trimethyl‐1,2,4‐Cyclopentanetrione
Authors: Buyck Laurent De , Verhé Roland , Kimpe Norbert De , Courtheyn Dirk , Schamp Niceas
Published: September 2010

Efficient procedures for the synthesis of 3,3,5‐trimethyl‐1,2,4‐cyclopentanetrione are described starting from the commercially available ketones 2,2,4‐trimethylcyclopentanone, 2,4,4‐trimethylcyclopentanone and 3,3,5‐trimethylcyclohexanone. The methods involve polychlorination and dehydrochlorination in dimethylformamide followed by hydrolysis.
X‐ray diffraction study of (±)‐decahydro‐9‐hydroxy‐9‐methylspiro|azuleno| 4,5‐b|furan‐6(2h),2'‐|1,3|dioxolan|‐2‐one (3aβ, 6aα, 9β, 9aβ, 9bα)
Authors: Declercq J. P. , Germain G. , van MEERSSCHE M. , Devreese A. , De Clerco P. , Vandewalle M.
Published: September 2010

C15H22O5, monoclinic, P21/c, a=17.775 (5), b=7.932 (3), c=11.048 (4) Å, β=116.18 (3)º V=1397.9 (8) Å3, Z=4, Dx=1.34 Mg m−3. The structure has been solved by direct methods and refined to a final R value of 0.070 for 2253 observed reflections. The stereochemistry of the title compound is as depicted for one enantiomer in 1; the configuration of the asymmetric carbons can be specified as C(1)R, C(4)S, C(5)R, C(6)R and C(7)R. The cyclopentane and the lactone are envelopes with pseudomirror planes passing through C(5) and C(7), respectively. The seven‐membered ring adopts a conformation intermediate between a twist‐chair (C2 symmetry) and a chair (C8 symmetry) conformation.
Polymères Bioactifs X. Insolubilisation de la β‐Amylase sur des Dérivés de la Cellulose
Authors: Simionescu C. R. , Bouzaher Y. , Dumitriu S.
Published: September 2010

Insolubilization of β‐amylase on cellulose carbonate and aminoaromatic derivatives of carboxymethylcellulose (CMC), such as N‐(4‐aminophenyl)‐CMC amide and N‐(4,4'‐diaminodibenzyl)‐CMC amide, is presented. The optimum coupling conditions depend on the nature of the carrier. By comparing the kinetic data for the reactions of insolubilized enzymes some conclusions are drawn regarding the influence of the support And of the binding mode on the activity of the coupled enzyme.
Étude du Comportement Chimique de Pyrano [2, 3‐c] Pyrazole‐3(2h)‐Ones Vis‐à‐Vis des Bases Azotées. II(f1). Réaction Avec Les Amines Aliphatiques
Authors: Maquestiau A. , van Haverbeke Y. , Vanden Eynde J.‐J.
Published: September 2010

Pyrano [2, 3‐c] pyrazole‐3 (2H)‐ones easily add aliphatic amines on the 6 position: the reaction is reversible. By prolonged heating and with primary amines only, the formation of alkylaminoethylidenepyrazolidin‐3, 5‐diones is observed.
Bonding Trends in Lanthanide Mandelates
Authors: Koppikar D. K. , Soundararajan S.
Published: September 2010

The lanthanide mandelates have been prepared by reacting the lanthanide hydroxides with mandelic acid (HL). The coordination number in these compounds has been discussed on the basis of analytical, infrared and electronic spectral, and thermal data. The mandelates have the general formula, LnL3.nH2O, where n3 for LnLa, Pr, Nd and Sm, and n=2 for LnGd, Dy, Br, Yb and Y. The infrared spectral data reveal that the mandelate ion is coordinated to the lanthanide ions in a bidentate fashion through the oxygen atoms of the carboxylate and the hydroxyl groups. The antisymmetric COO−, the δ OH, and the Ln‐O frequencies in the mandelates show a linear relationship with the ionic radius of the lanthanide ions. The infrared spectral and thermal data afford evidence of the coordination of all the molecules of water to the lanthanide ions. Hence, coordination numbers nine and eight have been assigned to the two sets of mandelates. This conclusion is supported by a study of the shapes of the hypersensitive transitions in the electronic absorption spectra of Nd and Br mandelates. The electronic spectra also suggest that the bonding in these compounds is predominantly ionic.
Analysis of Skeleton Remains, Ascribed to Mary of Burgundy, and of Soil Samples, Recovered from the Central Tomb of the Church of Our Lady, Bruges
Authors: Maenhaut W. , Cornelis R. , Cafmeyer J. , Mees L.
Published: September 2010

Skeleton remains and soil samples, recovered from the central tomb of the Church of Our Lady, Bruges, were analyzed for their major, minor and trace element content by means of instrumental neutron activation analysis (INAA), particle induced X‐ray emission (PIXE) and Rutherford back‐scattering (RBS). The results indicated that the reddish brown patinaed surface layer of the skeleton remains had a lead content of the order of 8 to 241, whereas that in the onderlying normal looking bone tissue was only 0.6%. The soil samples, recovered from inside the skull also showed abnormally high lead contents. It is concluded that the lead in the bone is of exogenous origin, ultimately originating from the lead coffin in which the body was buried. It is further suggested that the high lead concentration in the surface layer of the skeleton may be responsible for its reddish brown colour.
Détermination de la structure de la N, N‐diméthyl chloro‐4 benzamide‐oxime C9h11CL N2O
Authors: Tinant B. , Declercq J. P. , Germain G. , van Meerssche M.
Published: September 2010

The structure of the title compound has been investigated using x‐Ray diffractometer intensities in order to determine the configuration of the oxime group. The molecules appear to be in the E configuration. Crystal data are as follow: monoclinic, P2/c; a=6.197(1), b=7.505(2), c=22.975(5)Å, B=99.73(2)°; V=1053.1 Å3; Z=4; Dx=1.25 Mg m−3.
Applications of Mössbauer Spectroscopy to the Study of HDS Catalysts
Authors: Topsøe Henrik , Clausen Bjerne S. , Candia Roberto , Wivel Carsten , Mørup Steen
Published: September 2010

Mössbauer spectroscopy is one of the new tools which recently have been applied to the study of HDS catalysts. The technique has several unique features which make it especially useful in the study of such catalysts and it has given answers to some of the much debated problems, The studies have yielded insight into, for example.

The origin of promotion, (ii) the reason for catalytic synergy, (iii) the nature of the active phase, (iv) the observed similarities between unsupported and supported catalysts, and (v) loading and support effects. The article will review the available literature as well as bring forward some new results.
Pulse Polarographic Studies on the Adsorption of Adenine, Adenosine and Mono, Di and Triphosphate of Adenosine
Authors: Temerk Y. M. , Kamal M. M.
Published: September 2010

Adenine, adenosine and adenine mononucleotides (3′‐AMP, 5′‐AMP, 5′‐ADP and 5′‐ATP) were studied at various pH values by means of normal pulse polarographic measurements at the dropping mercury electrode. It was found that adenine, adenosine and adenine mononucleotides yield pulse polarographic peak. From its height and potential conclusions can be made about their adsorption effects at the charged interface. Adsorption effects in normal pulse polarography of adenine, adenosine and adenine mononucleotides were also investigated through the dependence of the pulse polarographic current on various parameters such as pH, temperature, adsorption time and bulk concentration of depolarizer. The potential dependence of the pulse peak height is of bell shaped type with an extended maximum region around the potential of electrocapillary maximum (Eecm) of the supporting electrolyte. For the same bulk concentration the pulse peak height decreases in the series adenosine, AMP, ADP and ATP, i.e. with increasing negative charge. Pulse polarography is particularly valuable for calculation of the values of adsorption parameters for the dilute layer (adsorption coefficient b, free adsorption enthalphy ‐ΔG °, interaction coefficient a) provided the span of the drop life before the application of the pulse is adjusted to a period sufficiently long to reach adsorption equilibrium.
The Infra‐red Spectra of Complexes with Planar‐dithio‐Oxamides Part I: The Neutral PdL2 Complexes
Authors: Hofmans H. , Desseyn H. O. , Aarts A. J. , Herman M. A.
Published: September 2010

The neutral complexes of planar dithio oxamides with Pd(II) are investigated by electronic and infrared spectroscopy and the assignments have been proposed for the fundamental vibrations considering a D2h structure for the R.R.D.T.O. and D.T.O. complexes and a C2h structure for the R.D.T.O. complex. The ligands act as bidentates and coordinate through sulfur giving square planar complexes.
Amino Steroids ‐ Further Studies with Conanine and Heteroconanine Systems
Authors: van De Woude G. , Biesemans M. , van Hove L. , Mertens J.
Published: September 2010

Treatment of any of the three following products, heteroconanol methiodide (3′), conanol methiodide (4′) or 18‐dimethylamino‐5α‐pregn‐20‐en‐3β‐ol (1), with a large excess of potassium hydroxide in hot ethylene glycol affords rapidly a mixture of heteroconanol (3, <56%>), conanol (4, <33%>) and the Δ 17(20) isomer of 1 (2,<11%>). The presence of such an isomer has not yet been reported in analogous reactions of related compounds. The Hofmann elimination product 1 is thought to be involved as an equilibrium intermediate in each of the three reactions; its isomer 2 should be formed by base‐catalyzed isomerization and not by eliminative ring fission.
Equilibrium Study of the Mixed Ligand Complexes of Cu(II), Ni(II), Co(II)‐AMINO ACID, 2, 2′‐bipyridyl and iminodiacetic acid with hydroxamic acids
Authors: Janardhan Rao M. , Sethuram B. , Navaneeth Rao T.
Published: September 2010

Formation constants of the mixed ligand complexes MAL where M = Cu(II), Ni(II) & Co(II); A = histidine, 2, 2′‐bipyridyl or iminodiacetic acid and L = N, 2′‐diphenylacetohydroxamic acid and 2, 2′‐diphenylacetohydroxamic acid have been determined in water ‐ ethanol (50% v/v) medium. Stability constants of ternary chelate were found to be less than the stability constant value of M:L complex. This trend in log K values is explained on the basis of electrostatic repulsion between the primary and secondary ligands. Remarkable stability of ternary chelates (Cu‐bip‐N,2′‐DPAHA) as indicated by the stabilization parameters are explained in terms of electronic effects, geometry of the complex and steric hindrance.
Détermination de la Structure de la Mopérone: Fluoro‐4' (Hydroxy‐4 p‐Tolyl‐4 Pipéridino)‐4 Butyrophénone
Authors: Tinant B. , Germain G. , Declercq J. P. , van Meerssche M. , Azibi M. , Draguet‐Brughmans M. , Bouché R.
Published: September 2010

The structure of mopérone has been investigated using X‐Ray diffractometer intensities in order to compare the molecular conformation with that of other butyrophenones.

Crystal data are as follows: monoclinic, P21/c; a = 16.907(8), b = 21.363(8), c = 10.825(4)Å, β = 96.87(3)°; V = 3882 Å3: z = 8; Dx = 1.22 Mg m−3.
Some Nuclear Reactions of Tropolones
Authors: Komolafe Olusegun Oluwole , Femi‐Onadeko Bankole
Published: September 2010

Tropolones are of known biological importance,1‐3 both in the plant and animal world. Their synthesis and physico‐chemical properties are therefore of some importance. Tropolone (2‐hydroxy‐2, 4, 6‐cyclo‐heptatriene‐l‐one), by virtue of its inherent aromatic characteristics, would be expected to undergo electrophilic substitution in a facile manner. This is found not to be the case. Substituted tropolones must therefore be produced by new reaction pathways, which necessarily involves more easily accessible intermediates. Such intermediates could possibly be the aminomethyl derivatives of tropolone, which are easily prepared by a simple Mannich condensation. Elaboration of these adducts could lead to more complex tropolones.

Nuclear substitution of tropolones

Friedel Crafts reactions of tropolones

An investigation of Friedel Crafts alkylations and acylations was undertaken using a variety of Lewis acids as catalysts.
Cobalt Molybdenum Catalysts Supported on Sodium Modified λ‐Al2O3: Characterization and Catalytic Activity in the Hydrogenolysis of Thiophene
Authors: Lycourghiotis Alexis , Defossé Camille , Delmon Bernard
Published: September 2010

A series of cobalt‐molybdenum‐alumina catalysts was fabricated using as carriers λ‐Al2O3doped with various amounts of sodium.

Over these surfaces the H.D.S. of thiophene has been studied. A considerable decrease in the catalytic activity was observed with increasing Na±content.

The decrease in the catalytic activity was explained in terms of structural modification of Mo active species caused by sodium.

D.R.S., X.P.S. and X‐ray spectroscopies were used to characterize the catalysts.
Preparation of Trans‐5‐Hydroxy‐l‐Pipecolic Acid and Cis‐4‐Hydroxy‐l‐Pipecolic Acid from l‐Baikiain (1, 2, 5, 6‐l‐Tetrahydropyridine‐2‐Carboxylic Acid)
Authors: Callens Roland E. A. , Anteunis Marc J. O. , Reyniers FranÇOise
Published: September 2010

Z‐trans‐5‐OH‐L‐pipecolic acid together with Z‐cis‐4‐OH‐L‐pipecolic acid is obtained in a 7:3 ratio by reduction of the oxymercuration product of Z‐L‐baikiain (Z‐1, 2, 5, 6‐L‐tetrahydropyridine‐2‐carboxylic acid). The opposite composition ratio is obtained using mercuric trifluoroacetate, thus giving access to the preparation of either of the two isomers.
Photoelectrochemistry of Ru(bpy)32+ in Basic Medium at SnO2 and Metal Electrodes
Authors: Kirsch‐De Mesmaeker A. , Nasielski J. , Willem R.
Published: September 2010

The influence of the pH on the photoelectrochemical behavior of Ru(bpy)32+ is examined at a highly doped SnO2 electrode. An important photocurrent increase from pH 11 to 13 is explained by the photochemical production of a long‐lived reductant generated from Ru(bpy)32+. Photocurrent observations at metallic electrodes and the photogalvanic cell behavior confirm this interpretation. Furthermore, a modification of the SnO2 electrode by the ruthenium complex has been pointed out.
Molecular Structure Analysis of Monoamine Oxidase Inhibitors IV. Crystal Structure of 3‐[4‐[(3‐nitrophenyl)‐methoxy] phenyl]‐6‐methoxymethyl‐2‐oxazinone: C19H20N2O6
Authors: Durant F. , Bufkens F. , Evrard G. , Lamotte C.
Published: September 2010

This paper is the fourth of a general study of structural properties of a series of new Monoamine Oxidase Inhibitors (MAOI's). The results of the X‐ray crystal structure analysis of an oxazinone derivative are related to and compared with those previously reported for oxazolidinone homologues.
Extraction, Assay and Conversion of NH. A Preparative Procedure for Isotopic Enrichment Determination
Authors: Grognet Pierre , Malaisse‐Lagae Francine , Sener Abdullah , Malaisse Willy J.
Published: September 2010

A method is described for the extraction of NH4+ from biological samples. This method can be combined with the enzymatic conversion of NH4+ to glutamate, which can then be used for measuring 15N isotopic enrichment. Emphasis is laid on the difficulties encountered when the samples contain NH4+ together with the amide derivative of monoaminodicarboxylic acids.
Diluent Influence on the Extraction of some Transition Metalchloride Complexes with Triïsoöctylamine
Authors: Verhaege M. , Claus G. , van Peteghem A.
Published: September 2010

Recently, chlorinated high density hydrocarbons have been proposed as diluent or as additive to more common solvents for the liquid‐liquid extraction of some base metals (1,2,3).

In this communication the extraction curves of some transition metals from chloride solutions with a currently used anionexchanger (triisoöctylamine) solved in perchloroethylene are presented. The results are compared with those obtained for more commonly used solvents in liquid‐liquid extraction: SHELLSOL K (an aliphatic diluent) and SOLVESSO 150 (an aromatic diluent).
Pyridines. Partie X1 ‐ Synthèse de Pyridyl‐ et Quinolylenamidines par Condensation Entre Composes Organolithiens et Benzonitrile. Nouveaux Intermediaires pour Réactions D'Heterocyclisation
Authors: Compagnon Paul‐Louis , Gasquez Françoise , Compagnon Odette , Kimny Tan
Published: September 2010

A series of methylpyridyl‐ and (methyl) quinolylphenylvinylbenzamidines has been synthesized by condensation of organopolylithium compounds derived from polymethylpyridines and ‐quinolines with benzonitrile. In diethyl ether, beside the enamidines, the reaction gives enolizable ketones. Triphenylimidazole, triphenyl‐s‐triazine and triphenylpyrimidine are isolated in the case of benzylmagnesium chloride. Possible routes leading to the various products are suggested. In diethyl ether, the conditions which give the enamidine derivatives in useful yields have been established. In liquid ammonia, on the contrary, no polycondensed products were isolated. The intermediate enamine and enamidine anions are trapped in diethyl ether by acylation of the reaction mixture before hydrolysis. With benzoyl or acetyl chloride, ethyl chloroformate, various C‐ and N‐acylated products (enolizable β‐diketones, enamides, acylenamides, N‐acylenamidines) and their cyclization products (pyrimidines) are obtained. The latter are also prepared from the isolated enamidines and benzoyl chloride.
Résultats Récents en Chimie Hétérocyclique du Germanium
Authors: Satge Jacques
Published: September 2010

Divalent germanium species: germylenes and germanium doubly bonded species (GeY YC, O,S,N‐,P‐,Ge) are powerfull synthetic reagents in organometallic chemistry. The germylenes exhibit properties analogous to those of carbenes and have been shown to insert into various ♀ bonds such as: carbon‐heteroelement, metal‐carbon, metal‐heteroelement, etc.… of heterocyclic derivatives with ring expansion. The additions of germylenes on various unsaturated compounds (alkenes, alkynes, dienes, carbonyl compounds, imines, nitrosobenzene) lead to cycloadducts which have generally a low stability except in the case of dienes. The doubly bonded germanium species are highly reactive and widely used in organometallic synthesis in various types of reactions such as: ‐ addition (or insertion reactions) on various ♀ bonds of organometallic compounds,

‐insertion reactions with ring expansion into small organic rings,

‐cycloaddition reactions on 1‐2, 1‐3 and 1‐4 dipolar reagents

‐condensation and exchange reactions.

The mechanism and the stereochemistry of some reactions are discussed.
Coordination compounds of heterocyclic AZO derivatives II‐transition metal chelates of some pyrazolone AZO dyes
Authors: Mahmoud M. R. , Adam F. A. , Yousef K. , El‐Haty M. T.
Published: September 2010

The chelates of some 4‐arylazo‐3‐amino‐pyrazolone derivatives with Mn(II), Fe(III), Zr(IV), Pd(II) and Ag(I) are prepared and characterized. It is concluded that the ligands and the complexes exist mainly in the hydrazone‐keto form. It is confirmed that such compounds are coordinated to the metal ion as monovalent bidentate ligands, L−, and the bonding sites are the oxygen of the carbonyl group and the α‐nitrogen of the arylazo group.
Sedum alkaloids, IV, the X‐ray crystal and molecular structure of sederine hydrochloride and the absolute configuration of sederine
Authors: Piccinni‐Leopardi Carla , Germain Gabriel , van Meerssche Maurice , Colau Brigitte , Hootele Claude
Published: September 2010

The absolute configuration of the three asymmetric atoms of sederine, a minor alkaloid isolated from Sedum acre, has been established through the use of Horeau's method together with a study by X‐ray diffraction of sederine hydrochloride.
Spectrométrie de Masse Des α‐Diazoimines. Réarrangement Des Cations‐Radicaux D' α‐Iminocarbenes en Phase Gazeuse
Authors: Maquestiau A. , Flammang R. , Meyrant P. , Regitz M. , Arnold B. , Schubert H.
Published: September 2010

The study of the mass spectra of six α‐diazo‐N‐cyanoimines and the collision‐induced dissociation/mass‐analysed ion kinetic energy spectra of their [M‐N2]+· fragment ions demonstrate the decay sequence: [α‐diazoimine]+·→ α‐iminocarbene]+·→ [ketenimine]+. This last ion is shown to be structurally identical to the one formed by electron‐induced cycloreversion of the ketenimine‐benzylideneaniline cycloadduct.
High Yield Synthesis of Filicinic Acid, Based on the Polychlorination of 4,4‐Dimethyl‐2‐Cyclohexenone Part II: Conversion of 2,3,5,6‐tetrachloro‐4,4‐dimethyl‐2,5‐cyclohexadienone into filicinic acid and related cyclohexadienones
Authors: De Buyck L. , De Kimpe N. , Verhé R. , Schamp N.
Published: September 2010

Filicinic acid (5) was prepared in 75‐80% overall yield from 4,4‐dimethyl‐2‐cyclohexenone (1). The key intermediate, tetrachlorodienone 2, underwent facile substitution of both β‐chlorine substituents by methoxide affording the bis enol ether 3 which was converted into dichlorofilicinic acid 4 in hot 85% sulfuric acid. Monohydroxy derivatives were obtained by treatment of 2 or 3 with hydroxide. Palladium‐catalysed low‐pressure hydrogenation of 4 under appropriate conditions produced monochlorofilicinic acid, filicinic acid or 5‐hydroxy‐4,4‐dimethyl‐1,3‐cyclohexanedione (8) with high selectivity.
The crystal structure of manganese(II)‐(±)‐1‐malate trihydrate
Authors: Lenstra A. T. H. , Dillen J.
Published: September 2010

Racemic manganese(II) (±)‐1‐malate trihydrate crystallizes in the space group Pcab, with Z=8 and a=14.201(8), b=14.656(4), c=8.265(5)Å. The Mn‐ion is surrounded by six oxygen atoms forming an octahedron, slightly distorted by the rigidity of one malate ion, acting as a bidentate ligand. The malate ion has the trans conformation in the OOC‐CH2‐CHOH‐COO chain. The racemic manganese salt and its optically active counterpart are practically equal in terms of the Mn‐coordination and the geometrical details of the malate anion.
Structure du Cholestadiene‐4,6 One‐3, C27H43O
Authors: Dupont L. , Dideberg O. , Krzyminiewski R.
Published: September 2010

The structure of cholesta‐4,6‐diene‐3‐one has been investigated using X‐ray diffractometer intensities. The final conventional R value is 0.06.

Crystal Data are as follow: orthorhombic, P212121, a=25.591 (5), b=15.089 (4), c=6.334 (3)Å, V=2445.8A3, Z=4. Dx=1.04Mgm−3, μ=4. 6cm−1.
Long‐acting contraceptive agents: X‐Ray study of levonorgestrel esters
Authors: Crabbé Pierre , Schlemper Elmer O.
Published: September 2010

The X‐ray crystal structure determinations of levonorgestrel (1) and its esters (2) to (7) have been performed in order to assign the molecular features and attempt to correlate the conformation of the molecules with their long‐acting contraceptive activity.

In the most active compounds, i.e., levonorgestrel butyrate (4), cyclopropylcarboxylate (6), and cyclobutylcarboxylate (7), the unusual orientation of the ester chains seems to affect the entire steroid framework. The stereochemistry of ring A is only slightly modified while the tetracyclic skeleton exhibits a more planar conformation than that of levonorgestrel (1) or the other esters (2), (3), and (5), and the ester grouping shields the 0 (17) ester position much more in esters (4), (6), and (7). Since levonorgestrel (1) and norethisterone (8) have very similar conformations, additional factors, different from the molecular geometry, seem to be responsible for the dramatic long‐acting contraceptive properties associated with these esters.
Contribution a L'Étude du Comportement du Chlore et du Brome Dans Les Solvants Nucléophiles
Authors: De Meyer M. , Levert J. M. , Vanclef A.
Published: September 2010

In this paper, we study the oxydant concentration stability of diluted halogen solutions of bromine, chlorine in organic solvents: acetonitrile, nitromethane, N,N‐dimethylformamide, N,N‐dimethylacetamide, 1 methylpyrrolidinone‐2, tetrahydrofuran, dimethylsulfoxide, tetramethylurea and tetramethylthiourea.

Raman spectroscopy examinations of halogen Solutions show undoubted formation of trichloride and tribromide ions in N,N‐disubstituted amide solvents. This specific chlorine solvation explains the immonium chloride formation observed during styren chloration in N,N‐dimethylformamide. Bromine solvation in dimethylsulfoxide and other nucleophilic solvents are also studied.
Étude Comparative de la Réactivité de L'Acetoacetate D'Éthyle et du 3‐Aminocrotonate D'Éthyle Vis‐A‐Vis de Composes Pyrazoloniques
Authors: Maquestiau A. , van Haverbeke Y. , Vanden Eynde J.‐J.
Published: September 2010

1‐phenyl‐3‐methylpyrazolin‐5‐one, 1,5‐dimethylpyrazolin‐3‐one and 1‐phenyl‐pyrazolidin‐3,5‐dione react with ethyl acetoacetate to yield pyrano [2,3‐c] pyrazole‐6‐ones. Starting from 1‐phenyl‐3‐aminopyrazolin‐5‐one or from 1‐methyl‐5‐aminopyrazolin‐3‐one, pyrazolo [3,4‐b] pyridin‐6‐ones are obtained.

When ethyl 3‐aminocrotonate instead of ethyl acetoacetate is used, the course of these reactions remains the same in most cases but yields are always higher.
New Applications of Dipolar Cycloaddition Chemistry Toward the Synthesis of Heterocycles
Authors: Padwa Albert , Chen Yon‐Yih , Koehler Konrad F. , Tomas Miguel
Published: September 2010

A new method for the preparation of β‐lactams has been developed. The protocol involves 1,3‐dipolar cycloaddition of nitrones with nitro substituted alkenes followed by a subsequent reorganization of the resulting 5‐nitroisoxazolidine isomer. The utilization of α‐silyl substituted amines as azomethine ylide equivalents has also been explored.
Hydrogen Bonding and Protonation Site in N,N‐Diethylnicotinamide
Authors: De Taeye J. , Maes G. , Zeegers‐Huyskens T. H.
Published: September 2010

The hydrogen bonded complexes between N,N‐diethylnicotinamide and proton donors such as phenol derivatives or hydrochlorid acid have been studied by infrared spectrometry. The thermodynamic parameters, the ΔνOH values and the shift of the νCO band to lower frequencies indicate that with phenol derivatives (pKa=10.2 ‐7.7 ), normal CO…HO hydrogen bonds are formed. The spectra show that the adduct with HCI is a proton transfer complex and that the protonation occurs at the nitrogen atom of the pyridine ring.
NMR Studies on Imidines. III.1H and 13C Nuclear Magnetic Resonance Study on the Tautomerism and Geometrical Isomerism of 3‐Iminoisoindolinone and Some Alkylated Derivatives. Observation of E and Z Isomers About a Free Imino Grouping
Authors: Spiessens Luc I. , Anteunis Marc J. O.
Published: September 2010

3‐Iminoisoindolinone (1) and some N‐alkyl derivatives (8, 9, 10, 11, 12, 16 and 17) have been fully examined by 1H and 13C NMR spectroscopy. 3‐(Methylimino) isoindolinone (12) cannot be obtained by reaction of 1 with methylamine, because it rearranges to 3‐imino‐2‐methylisoindolinone (11), which reacts further to 2‐methyl‐3‐(methylimino) isoindolinone (10). Both compounds have been shown to adopt the E configuration predominantly (88% E for 11 at‐55°C (CDCl3); 100% for 10). 3‐(Methylimino) isoindolinone (12) favours the Z configuration (96%).

Analogous results are found for the butyl derivatives (16, 17). 3‐Imino isoindolinone (1) is present as the imino tautomer for 70% in DMSO‐d6 solution as established by comparison of 13C NMR chemical shift values of 1 with those of model compounds, 3‐imino‐2‐methyl isoindolinone (11) and 3‐(dimethylamino) isoindoleninone (8). The tautomeric equilibrium is more extreme towards the imino form for the N‐methyl and N‐butyl derivatives 12 and 16. 2, 3, 4, 5‐tetrahydroisoindolino [2,1‐a] pyrimidin‐6‐one served as the imino model compound together with 10. 1H and 13C NMR data are given for several phthalic acid derivatives.
Étude Du Spectre Électronique Des Trichlorures: (n‐C4H9)4NCl3 et ϕ4 AsCl3
Authors: De Meyer H. , Levert J. M. , Vanclef A.
Published: September 2010

The electronic spectra of organic trichlorides (n‐C4Hg)4NCl3 and ϕ4AsCl3) in acetonitrile and dichloromethane are studied and compared with spectra of other trihalide ions: Br3−, I3−, BrCl2−, ICl2−. The apparent constant of the equilibrium, Cl2 + Cl− − Cl3−, is evaluated in acetonitrile with lithium chloride and tetrabutylammonium chloride. Typical trichloride absorption bands in saturated chlorine brines of NaCl (or hydrochloride solutions) are not observed and thus no trichloride complex ions are formed in aqueous phase.
Pyridines. XII1 ‐ Métallation Régiosélective De La S‐Collidine: Influence Du Solvant et Du Cation Associé Sur L'Isomérisation Des Carbanions Formes. Application a la Benzylation et a la Benzoylation
Authors: Compagnon Paul‐Louis , Kimny Tan
Published: September 2010

The metalation of s‐collidine l by PhLi in Et2O, THF and DME leads to the kinetic anion (la,S); in Et2O la is also the thermodynamic product. In THF and DME, (la,S) isomerizes into the more delocalized thermodynamic anion (lb,S), without implication of a steric effect; halflife times T at 23°C are 122 mn in THF, 2 mn in THF + excess of l, < 1 mn in THF + TMEDA, at 22°C 28 mn in DME. In HMPT, PhLi deprotonates l giving within 2 mn an equilibrated mixture la + lb, but (lb,S) is still prevalent. In liquid NH3, with NaNH2 and LiNH2, (lb,S) is the only detectable anion. After the deprotonation step, the anions are trapped by PhCH2Cl (rate constant k3) or PhCN (k2). Note that the condensation with PhCN seems irreversible in DME, but reversible with protonation when liquid NH3 is evaporated and replaced by Et2O. With Li+ cation, a kinetic control is superimposed to the thermodynamic equilibrium la ‐ lb (k), the rate constants (Scheme 2) decreasing in the following order kb3 > kb3 > kb2 > kb2. These various results (selective metalation, isomerization, relative reactivities of la and lb versus PhCH2Cl and PhCN) are interpretable in terms of solvent donating effect DN and acceptor‐number AN (V. Gutmann13) and of the structure of la‐M and lb‐M (contact ion pair and solvent‐separated ion pair).
Polarographic Study of Mixed Ligand Complex Formation in the CD(II) ‐ Cl−‐2,2'‐Bipyridyl System
Authors: Mambetkaziev E. A. , Abilova M. U. , Shaldybaeva A. M. , Zhdanov S. I. , Jarkesheva Sh. A.
Published: September 2010

Complex formation in the system, containing Cd2+, Cl− and 2,2'‐bipyridyl, was studied in the aqueous medium at 25°C using the classic polarographic method. The Schaap‐McMasters method was employed to calculate the stability constants of mixed ligand complexes. The formation of the complexes [CdCl bipy]+, [CdCl2bipy] and [CdCl bipy2]+ was established under the given experimental conditions.
Étude Rmn‐1H Des Hélicènes ‐ 2e Partie
Authors: Defay Nicole , Martin Richard H.
Published: September 2010

The proton chemical shifts of eight benzenoid helicenes, namely: [7], [8], [9], [10], [11], [12], [13] and [14] helicenes, have been assigned by the study of deuteriated or substituted derivatives. The evolution of the chemical shifts with the growth of the helix is discussed.
Some Ring‐Transformation Reactions of Desaurins
Authors: L'abbé Gerrit , Vangheluwe Patricia , Toppet Suzanne , King Geoffrey S. D. , Meervelt Luc Van
Published: September 2010

The desaurin 3, whose stereochemistry has now been established by an X‐ray crystal structure analysis, can be used as a thioketene equivalent (11). Reactions have been carried out with sodium azide/dimethyl sulfate, N,N‐diethyl‐aminopropyne, N‐methyl benzaldimine, tert‐butyl isonitrile and NaN3/CS2 to give the products listed in Schemes I, IV and V. Simple thioketenes (e.g. 16) react analogously with tert‐butyl isonitrile, but not with imines where C‐C adducts are formed instead of C‐S adducts.
Data Collection in X‐ray Single Crystal Diffractometry : Strategy and Error Sources
Authors: De Wolf M. , Lenstra A. T. H.
Published: September 2010

A description is given of (i) tests for the stability and performance of the diffractometer, in particular the mechanical wear and tear, (ii) the influence of wavelength dispersion and mosaic spread on the determination of scan parameters and (iii) experiments showing the importance of multiple scattering on strong reflections. It is demonstrated that counting statistics seriously underestimates the error limits of intensities obtained in single crystal X‐ray diffractometry.
Four‐Membered Ring Peroxide Heterocycles: Photochemistry Through the Backdoor
Authors: Adam Waldemar , Baader Wilhelm J. , Babatsikos Chrisostomos , Schmidt Ernst
Published: September 2010

The unusual property of four‐membered ring peroxide heterocycles (1,2‐dioxetanes) to produce electronically excited carbonyl fragments on thermal decomposition is discussed. The synthetic tools for the preparation of such labile substances and the analytic methods for assessing excitation yields are covered. Using the complete series of methylated derivatives of the parent 1,2‐dioxetane, their thermal stability and excited state production is rationalized in terms of a modified diradical mechanism. With the help of bisdioxetanes, it is shown that generation of upper excited states is improbable, despite the fact that sufficient energy is available for this purpose. Attachment of dioxetanes to biomolecules via mild esterifications provides interesting opportunities for photobiological exploration.
Anchor Effect in HDS of Phenothiazine, Phenoxathiine, Thianthrene and Thioxanthene on Sulfided Nio‐Moo3/γ‐Al2o3Catalyst
Authors: Aubert C. , Durand R. , Geneste P. , Moreau C.
Published: September 2010

The rate constants of hydrodesulfurization of phenothiazine, phenoxathiine thianthrene and thioxanthene on sulfided NiO‐MoO3/γ‐Al2O3catalyst, at 340°C under 70 bar H2, are similar to one another and about 10‐fold higher than that of dibenzothiophene.

From comparison with HDS of dibenzothiophene, the presence of a second heteroatom, N,S,O or of a methylene group has no or little effect on the HDS rates of the title compounds. The observed rate enhancement could result from differences in the strength of adsorption between the adsorbed state and the transition state (anchor effect) which depends on whether the molecules are planar or folded.

The comparison of the rate constants of hydrodeoxygenation of homologous oxygenated compounds, xanthene and phenoxazine, with that of dibenzofurane leads to the same conclusion.
Transition Periods of the Activity of Co‐Mo/Al2o3 Catalysts in Thiophene Hydrodesulfurization
Authors: Dobrovolszky M. , Nagy Z. , Pall Z. , Tétényi P.
Published: September 2010

Hydrodesulfurization (HDS) of thiophene was studied over Co‐Mo/Al2O3 catalysts of various composition. Sulfidation was carried out by the reactant itself, alternating with dimethylsulfoxide. Mo‐rich catalysts reached their maximum activity level when the upper limit of sulfidation was not higher than 15%. From 50–60% sulfidation, a slow activity decrease appeared. Co‐rich catalysts reached very rapidly (2–3% sulfidation) a very low, very stable activity level. The C4‐selectivity was 80–96% at the quasi‐constant activity level. Butane yields were roughly proportional to the HDS activity. The predominance of cis‐2‐butenes permitted us to suggest a mechanism for thiophene HDS.
Influence of Reduction / Sulfidation Treatments on the Physico‐Chemical and Catalytic Properties of Unsupported Cobalt‐Molybdenum/Hydrodesulfurization Catalysts
Authors: Göbölös S. , Wu Q. , Ladriere J. , Delannay F. , Delmon B.
Published: September 2010

Unsupported CoMo sulfide catalysts prepared by the homogeneous sulfide precipitation method were submitted to 3 MPa 4% H2S‐H2 at 573K, and 0.1 MPa H2 at 573 and 723K. The samples were characterized by MES, XPS, XRD and temperature‐programmed sulfur extraction. Their activity was measured in the HDS of thiophene and hydrogenation of cyclohexene. MES reveals the presence of Co9S8, CoS1+x, Co‐Mo‐S and two unidentified species. Treatment under H2 at 573K caused an increase of activity which was correlated with an increase of the Co9S8 concentration at the expense of all other species. Treatment under H2 at 723K caused a further increase of activity which was correlated with the sintering of the Co9S8 phase. Part of the sulfur extracted by treatment under H2 up to 733K cannot be recovered by subsequent treatment under H2S/H2. These results do not provide straightforward evidence for deciding between the current models used for explaining the synergetic effect, namely the existence of a Co‐Mo‐S phase or the remote control hypothesis. The sulfur deficiency of the catalyst appears to play a major role in the activity.
Catalysis by Polymers. V. Some Kinetic Aspects on the Polymer Catalyzed Reactions of Oxiranes
Authors: Oprea S. , Dumitriu E. , Hulea T. , Hulea V.
Published: September 2010

The esterification of epichlorohydrin with acrylic acid in the presence of various macro‐ and micromolecular catalysts has been investigated. The influence of concatenation of the catalytic functional groups on the reaction rate had been studied too.

The previous studies1–4 in the field of polymer catalyzed reactions of oxiranes with organic acids have shown some interesting aspects related to the behaviour of catalytic functional groups which are attached to the polymer backbone. The aim of this paper was to study the concatenation effect of the catalytic functional groups both in the homopolymers and copolymers on the reaction rate of esterification; for the same purpose the small‐molecule analogues were used as references.
Spectroscopic Properties of β‐Phenethyl‐Tin Compounds
Authors: Gielen Marcel , Vermeulen Martine
Published: September 2010

The 60 MHz NMR and 70 eV mass spectra of thirteen β‐phenethyltin compounds are described and discussed.
Improved Synthesis of 2‐Hydroxy‐4,4,6‐Trimethyl‐2,5‐Cyclohexadienone, Useful as a Flavoring Additive
Authors: Buyck Laurent De , Zi‐Peng Yao , Verhé Roland , Kimpe Norbert De , Schamp Niceas
Published: September 2010

The title dienone 1, useful for modification, improvement or increasing organoleptic properties of tobacco, sucrose syrups, flavored beverages, was prepared in 40–558 overall yield from isophorone, by chlorination of 2‐hydroxy‐isophorone (2), rearrangement into 6‐chloro‐2‐hydroxyisophorone (5) and de‐hydrochlorination. An excellent yield of 3‐chloro‐2‐hydroxy‐4,4,6‐trimethyl‐2,5‐cyclohexenone (12) was obtained by chlorination of 5 followed by dehydro‐halogenation.
Reaction of Titanium and Nickel‐Titanium Catalytic Heterogeneous Systems With Acetone
Authors: Malinowski Marek
Published: September 2010

The reaction of acetone with a low‐valent titanium species anchored on silica gel was studied in heterogeneous media. Aldol type condensation products, mesitylene and mesityloxide, were observed as main products. The influence of nickel and cyclopentadienyl ligands on the reaction was observed.
Non‐Catalytic Reduction of α‐Oximinoketones and α‐Oximinoalcohols to erythro‐2‐Amino‐1‐Arylalkan‐1‐Ols
Authors: Oppong‐Boachie Francis Kwabena
Published: September 2010

A non‐catalytic reduction of α‐oximinoketones 1 and α‐oximinoalcohols 2 to erythro‐2‐amino‐1‐arylalkan‐1‐ols 3 with lithium aluminium hydride is reported. The erythro‐2‐amino‐1‐arylalkan‐1‐ols are isolated as their hydrochlorides 5 and characterised as the erythro isomers by benzoylation.
Infrared Study of the Interaction Between Esters and Hydrogen Chloride or Bromide In the Liquid State
Authors: Vanderheyden L. , Zeegers‐Huyskens TH.
Published: September 2010

The interaction between six esters and hydrogen chloride or bromide is studied by infrared spectrometry. The formation constants determined in carbontetrachloride are much lower than those expected from the gas phase acidities of the hydrogen halides. This effect is ascribable to an entropy effect connected with a freezing of rotation of the acid molecules. With HCl, only normal hydrogen bonds are formed and the relative frequency shifts of the νHCl band and of the νC=O vibrations are linearly related, independently of the polarity of the medium and of the temperature. The infrared spectra of the HBr complexes show the characteristics of strong hydrogen bonds
Characterisation of Chromium Doped Raney Nickel Catalysts
Authors: Kordulis C. , Doumain B. , Damon J. P. , Masson J. , Dallons J. L. , Delannay F.
Published: September 2010

Two chromium‐doped Raney nickel catalysts have been prepared from Al‐Ni‐Cr alloys where Cr was introduced in such a way as to substitute for nickel in the Ni2Al3 intermetallic phase. In comparison with the undoped catalysts, the BET and metallic surface areas remain little affected but more aluminium is retained after etching. X.P.S. shows that aluminium and nickel are in the metallic state whereas chromium is completely oxidized. Very large amounts of chromium are found on the surface, which suggests migration of chromium to the surface during leaching. Analytical electron microscopy indicates that the local chromium concentration is not perfectly uniform. Electron probe microanalysis of the precursor alloy reveals the segregation of part of chromium in a separate phase. These results are evaluated in the framework of the available literature data on the microstructure of Raney nickel catalysts.
A High‐Yield Selective N(3)‐Alkylation Process of Hydantoins Using Dimethylformanide Dialkyl Acetals
Authors: Poupaert Jacques H. , Smeyers Claude , Böttcher Patrick
Published: September 2010

A selective N(3)‐alkylation process of 5‐substituted hydantoins is described. Treatment of hydantoins with excess of dimethylformamide dialkyl acetals at 100°C results in N(3)‐alkyl derivatives in 69–90% yield.
Asymmetric Hydrogenation of Dehydrovalyl Peptides
Authors: Calderón S. , Cativiela C. , Mayoral J. A. , Meléndez E.
Published: September 2010

Both N‐benzoyl‐Δ‐valyl‐L and D‐phenylalanine aethyl esters were hydrogenated at atmospheric pressure in quantitative yield, using 5% Pd/C suspended in n‐propanol. Diastereoselectivity is low but in line of expectations.
Synthesis of 5‐Diazomethyl Substituted V‐Triazolo [4,5‐D] Pyrimidines
Authors: L'abbé Gerrit , Godts Françoise , Toppet Suzanne
Published: September 2010

ABSTRACT. The condensation of 5‐azido‐4‐cyano‐1‐substituted‐1,2,3‐triazoles with active methylene nitriles in the presence of a strong base yields the title compounds 6 which exist in equilibrium with the tricyclic systems 5. The equilibrium position is shifted towards the diazo forms for X‐H and for X‐COOEt in non‐polar solvents, thus giving the first examples of open‐chain diazo functions attached to a pyrimidine ring at the 2‐position.
Diazoverbindungen‐671) Elektrophile Diazoalkansubstitution Mit Donorsubstituierten Kationen
Authors: Regitz M. , Weise G. , Lenz B. , Förster U. , Urgast K. , Maas G.
Published: September 2010

The imidazolinium chloride 8 reacts with diazomethyl compounds 3 (in the presence of an amine) or with metal derivatives of 3 under the formation of the 2‐(diazomethyl) imidazolidines 9. Compounds of the same type are received by treatment of the electron‐rich olefine 10 with 3 at elevated temperature. An analogous substitution process at 3 with the donor‐stabilized salts 13 and 17 produces stable 2‐(diazomethyl) benzthiazolines (14) and 6‐(diazomethyl) hexahydro‐1,3,5‐triazines (18) respectively.

Thermolysis and photolysis of 9 mainly yield tetrahydro‐1,4‐diazines (21) by 1,2‐N‐shift of the carbene precursors 20; moreover the hitherto unknown isomerization reaction of the diazo compounds 9 to the azines 25 has been observed. In the thermal decomposition of 14 the formation of 2‐methylenbenzthiazolines (28) is preferred whereas photolysis of the same diazo compounds affords mixtures of 28 and 1,4‐benzothiazines 30. The olefines 28 are characterized by protonation (31) and reaction with the cyclic azo compound 32 (34).
Polarographic Study of the Catalytic Prewave of Co(II) in the Presence of 5,5‐Dimethyl‐1,3‐Cyclohexanedione Dithiosemicarbazone Analytical Applications
Authors: Misiego A.Sánchez , Guiberteau Cabanillas A. , Garcia‐Moncó Carra R. , Caro Gámez C. , Garcia Garcia P.
Published: September 2010

The dissolutions containing Co(II) in a Tris‐HCl medium and in the presence of perchlorate of 5,5‐dimethyl‐1,3‐cyclohexanodione dithiosemicarbazone (DYDT‐HClO4) produce a prewave that has been studied by means of classical polarography (DC) and differencial pulse polarography (DPP). The catalytic nature of the prewave has been established and the possible electrode mechanism proposed. The analytical possibilities of the mentioned prewave have also been analyzed in order to determine the DYDT, Hg(II) and Ag(I).
Synthèse Des Pyrazolyl‐1 Benzimidazoles A Partir Des Dihydro‐1,3(2H) Benzo[2,3‐b] Diazepine‐1,5 Ones‐2
Authors: Essassi E. M. , Salem M.
Published: September 2010

Hydrazinolysis of 4‐phenyl 1,5‐benzodiazepine 2‐thiones 2a‐2b gives N‐(5 (3)‐phenyl 3(5)‐pyrazolyl) 1‐amino 2‐aminobenzene 3a‐3b. The compounds 3a‐3b have been used as precursors to prepare the 1‐[(5)3‐phenyl (3)5‐pyrazolyl] benzimidazoles 5a‐5h.
NMR Imaging Machine Using Components of Commercial HR Spectrometers
Authors: Dereppe J. M. , Lemercinier X. , Moreaux C. , Haut H.
Published: September 2010

Two dimensional mapping of H spin densities in test objects were obtained using a projection reconstruction method. The experiments were carried out on a modified commercial spectrometer. The spatial distorsions of the system are discussed and illustrated.
Comportements Chimique et Électrochimique dans les Hydroxydes Alcalins Fondus. I. Si(IV) ET Ge(IV)
Authors: Claes P. , Peeters G. , Glibert J.
Published: September 2010

The study of the dissolution reaction of the silicium and germanium dioxides was carried out in the NaOH‐KOH (49 mole%) eutectic mixture at 210°C and in pure NaOH at 350°C. The initial acidobasicity of these solvents as well as the CO2‐ and CO modifications after addition of the Si(IV) and Ge(IV) solutes were measured by an original method using linear sweep voltammetry at a platinum electrode. This procedure was nevertheless ineffective in acidic NaOH medium because of the distortion of the water reduction peak by the cathodic front. In this case, the water liberated by the reaction was eliminated by a flow of dry nitrogen and collected in a cell containing anhydrous MgClO4. The equilibrium conditions obtained by addition of minute amounts of SiO2 and GeO2 were determined by aging of the solutions. The SiO44‐ and GeO44‐ oxyani ons were formed in the respective acidic or basic melts according to the reactions:
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Theoretical Study of the Electronic Structure of Ketene, Ketenimine, Keteniminium Ion and Related Cumulenes. Evaluation of a 1,2 Dipolar Model
Authors: Sonveaux E. , André J. M. , Delhalle J. , Fripiat J. G.
Published: September 2010

Molecular orbital and configuration interaction calculations have been performed by ab initio methods for allene, ketene, ketenimine and keteniminium ion. Vinylketene and vinylketenimine were also investigated. The electronic populations, the frontier orbital energies and coefficients were deducted. A 1,2‐dipolar model of heterocumulenes is proposed. The experimental results related to the cycloadditions of these heterocumulenes are discussed on the basis of this model.
Ring Enlargement of the β‐Lactam Nucleus of Penicillins
Authors: Marchand‐Brynaert J. , Ghosez L.
Published: September 2010

Using penicillins as starting materials, a general synthetic route to the bicyclic compounds 7 has been established; they formally result from a ring enlargement of the ß‐lactam with insertion of one nitrogen atom. The key‐step of the procedure is a very mild Lossen rearrangement of hydroxamic acids intermediates upon treatment with N,N‐diethylaminopropyne.
Pyridines. XIII1‐Acylation de Pyridyl‐Lithioènamines Primaires Synthèse de Pyridyl‐Ènamides et de Naphtyridin‐1, 6 Ones‐5
Authors: Compagnon Paul‐Louis , Gasquez Françoise , Kimny Tan
Published: September 2010

The primary lithioenamine 4a is an ambivalent nucleophile resulting from the condensation of benzonitrile with 2‐s‐collidyllithium. Acylation of 4a by acetyl, benzoyl, N, N‐dimethylcarbamoyl chlorides, ethyl chloroformate or methyl benzoate leads to β‐C‐acylated 5, N‐acylated 6 (enamides) and β‐C, N‐diacylated 7 compounds. N‐acylation predominates upon C‐acylation with the studied aliphatic acid chlorides, contrary to benzoylation. 4, 6‐Dimethyl‐2‐pyridyl‐acetate 17 and‐acetamide 18 are formed and their origin is discussed. Thermocyclization of certain enamides, carbamates 6c, 7c and urea 6d leads to 2, 4‐dimethyl‐7‐phenyl‐1, 6‐naphthyridin‐5 (6H)‐ones 9a and 9b, and not to pyrido [1, 2‐c]pyrimidones 8.