bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculation of Diagonal Force Constants by the Stepwise Coupling Method: M.P.E.M. (Matrix Polynomial Expansion Method)
Authors: Alix Alain J. P. , van Der Veken Benjamin , Isotani Sadao , Manfait Michel
Published: September 2010

The calculation of an approximate Simple symmetry Valence Force Field including determination of diagonal symmetry valence force constants is achieved by using an iterative process derived from the Stepwise Coupling Method (SCM) in the form of the Matrix Polynomial Expansion Method (M.P.E.M.) of Alix. The discussion on the method itself and the comparison with similar methods such as the Eigen‐Vector Method (EVM) is given in detail. Numerical examples are given to illustrate the effectiveness of the method.
X‐ray Diffraction Study of 2,4a,4b,5,6,7,8,9,9a,10‐Decahydro‐7, 10‐Dihydroxy‐2, 4a‐epoxy‐8‐methylene‐7, 9a‐Methanobenz |a| Azu‐lene‐1‐Carboxylic Acid Ethyl Ester (2α, 4aα, 4bβ, 7β, 9aα, 10β)
Authors: van Meerssche M. , Declercq J. P. , Grootaert W. M. , De Clercq P. J.
Published: September 2010

C19H22O5, monoclinic, P21/a, a = 16.298(6), b = 8.359(2), c = 13.183(3) Å, β = 112.32(2)°; V = 1661.4(8)Å3, Dx = 1.32 g cm−3 for Z = 4.

The structure has been solved by direct methods (MULTAN 80) and refined to a final R value of 0.051 for 2017 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(3)R, C(6)R, C(8)S, C(9)R, C(10)R, and C(13)S. The five‐membered B ring is a half‐chair with pseudodiad axis through C(10). The six‐membered ring of the bicyclo|3.2.1| octane substructure adopts a distorted chair conformation.
The Determination of the Rotational Strength of the Gauche C‐C‐C‐SH Unit, Based on the 1H NMR Conformational Analysis of 2‐Butanethiol
Authors: Tavernier D. , Hosten N. , Anteunis M. J. O. , Spiessens L. I.
Published: September 2010

2‐Butanethiol was analysed by 1H NMR spectroscopy and its conformational composition in CDCl3 was determined: a: 0.53; g+: 0.35; g−: 0.12 (see Table I). The rotational strength of the gauche C‐C‐C‐SH fragment was thus estimated to be 126°. Analogously, the optical activity of 2‐butanol was related to its conformational composition, as determined by 1H NMR spectroscopy (T = 298 K): a: 0.45; g+: 0.32; g−: 0.23.
Ring Current and Aromaticity in Annulenes
Authors: Verbruggen A.
Published: September 2010

IF T0 ‐ Ti is the chemical shift difference of outer and inner protons in annulenes, S is their ring area and REPE their resonance energy per π‐electron, the linear correlation (T0 ‐Ti)/S=k.REPE is confirmed, both in theory and practice.
Prominent Aspects of Electroorganic Synthesis in β‐Lactam Chemistry
Authors: Torii Sigeru , Tanaka Hideo , Sasaoka Michio , Saitoh Norio , Siroi Takashi , Nokami Junzo
Published: September 2010

The potentiality of electrolysis procedures in the penicillin‐cephalosporin conversion as well as in the direct transform of penicillins into oxazolineazetidinones as an intermediate for the preparation of the sulfur‐free analogues of cephalosporins are discussed. Especially, a chemoselective electrolytic chlorination of methyl group of 3‐methyl‐3‐butenoate moiety of thiazolineazetidinone derived from penicillins, a direct synthesis of 3′‐thiosubstituted cephalosporins from the thiazoline‐azetidinones, an improved synthesis of exomethylenecephams, an efficient route to 3‐chloromethyl‐Δ3‐cephems, electrochemical S‐S bond fission of 4‐(2‐benzothiazolyldithio) azetidinones, a direct transformation of penicillins into oxazoline‐azetidinones by chloride salt‐promoted electrolysis, and a versatile intermediate for new β‐lactam antibiotics are presented.
Spectres RMN‐1 H et‐13 C Des Acides Mercapto‐2 Pyridinecarboxylique‐3, Mercapto‐3 Pyridinecarboxylique‐2 et de Leurs Derives Methyles Correspondants
Authors: Gelbcke M. , Grimée R. , Lejeune R. , Thunus L. , Dejardin J. V.
Published: September 2010

Proton and carbon‐13 chemical shifts and coupling constants of 2‐mercapto‐3‐pyridinecarboxylic acid, 3‐mercapto‐2‐pyridinecarboxylic acid and their seven respective methylated derivatives are reported. Substituent effects are discussed.
Rates of alkaline racemisation of carbobenzoxy protected pentachlorophenyl esters of γ‐Thiapipecolic acid and γ‐thiaproline
Authors: Wante Dirk P. M. , Borremans Frans A. M. , Anteunis Marc J. O.
Published: September 2010

Racemisation rates of Z‐blocked pentachlorophenylesters of the imino acids proline, pipecolic acid and their γ‐thia congeners are measured in triethylamine chloroform or tetrahydrofuran as the base/solvent system. The data is discussed in relation to the corresponding (but different) racemisation behaviour of the same residues in cyclic dipeptides.
Ouverture Par Les Orcanolithiens D'Isothiazoles et Isoselenazoles Heterocondenses
Authors: Onvamboko N. V. , Weber R. , Fauconnier A. , Renson A.
Published: September 2010

The ring‐opening of bi‐and tricyclic systems bearing an isothiazole or isoselenazole ring fused to a thiophene or a selenophene ring was studied by their reaction with methyl lithium.

The ring‐opening of the nitrogen ring occurs preferentially, except when, in a tricyclic system, the selenophene ring is central and fused to an isothiazole ring. In this case, the selenium heterocycle is opened before the nitrogen ring.
Structure and Stability Constants of Some Transition and Rare Earth Metal Complexes with Eiknogen
Authors: Abou‐Elwafa S. M. , Elzawawi F. M. , Issa R. M.
Published: September 2010

The complex formation of divalent ions, Mn, Co, Ni, Cu, Zn, Cd; the trivalent ions, Fe, Y, La‐Lu and U ion with eiknogen have been investigated spectrophotometrically and potentiometrically in 75% (v/v) dioxane. The metals form 1:1 and 1:2 complexes. Stability constants log K1 and log K2 are determined. The complexes formed have been characterised by elemental analyses and infra‐red spectral data from which bonding mode have been suggested.

Phenolic ligands are frequently used as complexing agents for the detection and determination of metal ions in solution1,2. Eiknogen (1‐amino‐2‐naphthol‐4‐sulphonic acid) is usually used for the determination of low silicate and arsenate ion concentrations3, however, few studies on metal chelates with eiknogen are also reported. It was considered, of interest, to study the complex formation of some transition metals with eiknogen and determination of their structures and stability constants.
The Analysis of the Homogeneous Saponification Reaction Applied to High Pressure Ethylene Vinylacetate Copolymers Part II: Influence of the Reaction Parameters on the Formation of EVA1/EVA1VA Polymers
Authors: Koopmans R. J. , Van Linden R. Der , Vansant E. F.
Published: September 2010

The influence of 4 reaction parameters on the homogeneous saponification method is examined. Firstly, the use of xylene, cyclohexane and tetrachloromethane instead of toluene indicates some experimental complications. It could however be concluded that a changing solubility parameter had a minor effect on the VA conversion rate. Secondly, reactions in an ethanol or a 2‐propanol medium are faster than when a methanol medium is used. Thirdly, it is not possible to control the % wt conversion VA only by a suitable amount of potassiumhydroxide. A larger than expected % wt conversion VA is observed, due to a base catalyzed transesterification sidereaction. Fourthly, a methanol concentration change influences the contribution of the sidereaction. Furthermore, the methanol and potassiumhydroxide concentration influence, on the VA conversion rate is not independent of each other.
Studies on the Dissociation Constants and Ion‐Solvation in Aqueous Ethanol, Non‐Aqueous Solvents and their Aqueous Mixtures of Some Benzocyclobuten‐1 (2H) Ones
Authors: Wasif Saad , Nashid Barsoum , Iskander George M.
Published: September 2010

The pK'a values of five 4‐hydroxybenzocyclobuten‐1 (2H)ones (I) in aqueous ethanol, dioxane, acetonitrile and dimethylformamide have been determined. The Hammett parameter ρ varies for each phenolic ketone with the aqueous solvent composition, which reflects possible sensitivity to solvent polarity. The molar free energies of transfer of (I) from water to 20‐60 wt % of organic solvent‐water mixtures haven evaluated. The results so obtained, are explained by a structural theory of ion salvation.
Étude Structurale Des Stilbènes I. Structures Par Diffraction de Rayons X de Trois α‐Cyanostilbènes
Authors: Tinant B. , Touillaux R. , Declercq J. P. , van Meerssche M. , Leroy G. , Weiler J.
Published: September 2010

The X‐Ray crystal and molecular structures of three α‐cyanostilbene derivatives were solved by direct methods from diffractometer data. (I) Trans‐4′‐dimethylamino‐4‐nitro‐α‐cyano‐β‐ethylstilbene, C19 H19 N3 C2, is triclinic, P 1, with a=10.725(3), b=10.860(3), c=8.451(2)Å, α=113.24(3), β=79.56(2), γ=111.13(3)°, V=842.8 Å3, Z=2. (II) Cis‐4′‐nitro‐α‐cyanostilbene, C15 H10 N2 O2, is monoclinic, P21, with a=5.655(2), b=17.004(5), c=6.521(2) Å, β=95.50(3)°, V=624.1 Å3, Z=2. (III) Cis‐4‐nitro‐α‐cyano‐β‐methylstilbene, C16 H12 N2 O2, is monoclinic, C2/c, with a=23.104(3), b=10.319(2), c=13.310(4)Å, β=118.08(2)°, V=2799.8 Å3, Z=8.

In the three compounds, the phenyl groups are twisted out of the ethylenic bond plane in order to avoid steric hindrance. The C(phenyl)‐CC bond angles are significantly greater than 120° except around C(β) in I and III.
X‐Ray diffraction study of 5‐hydroxy‐6‐methyl‐14‐oxatetracyclo|7.4.11,11.O2,6|tetradecan‐8‐one (lα, 2α, 5β, 6β, 9β, 11α)
Authors: van Meerssche M. , Declercq J. P. , van Royen L. A. , De Clercq P. J.
Published: September 2010

C14 H20 O3, monoclinic P21/n, a=14.479(5), b=11.693(5), c=7.139(2)Å, β=98.70(3)°; V=1194.7(7)Å3, Dx=1.31 g cm−3 for Z=4. The structure has been solved by direct methods (MULTAN 80) and refined to a final R value of 0.046 for 1402 observed reflections. The stereochemistry of the title compound is as depicted for one enantiomer in 1; the configuration of the asymmetric carbons corresponds to C(5)S, C(8)S, C(9)S, C(13)S, C(14)R and C(17)S (numbering according to steroid convention). The five‐membered D‐ring is a quasi‐envelope with pucker at C(13). The six‐membered C‐ring adopts a distorted boat conformation.
Activation Collisionnelle D'Ions Fragments Générés en Région Libre de Champ D'Un Spectromètre de Masse a Trois Secteurs
Authors: Maquestiau A. , Flammang R. , Meyrant P.
Published: September 2010

The structure of some fragment ions formed in the source and in the first field‐free region (FFR) of a triple sector mass spectrometer has been investigated by the collisional activation technique. It is shown that the elucidation of fragmentation pathways by metastable peak analysis may lead to erroneous conclusions. Indeed, high energy (source) fragmentation and the corresponding low energy (FFR) processes produce frequently isobaric or even isomeric ions.
Acétonylation Radicalaire de la Norbornanone‐2 Par Réaction Avec le Percarbonate de O,O‐t‐Butyle et O‐Isopropenyle
Authors: Villenave J‐J. , Jaouhari R. , Baratchart M. , Filliatre C.
Published: September 2010

The free radical decomposition of O,O‐t‐butyl and O‐isopropenyl peroxycarbonate in 2‐norbornanone leads to isomeric derivatives of the solvent. The products are identified using 13C NMR spectroscopy. The composition of the reaction mixture depends on the concentration of the peroxycarbonate solutions. At lowest concentrations, intermolecular transfer reactions enhance markedly the relative amounts of the 3‐acetonylated isomer.
Synthesis of a Series of 12‐Oxo‐5α‐Steroids with Variable 17β‐Side Chain
Authors: Biesemans M. , van de Woude G. , van Hove L.
Published: September 2010

5α‐Androstan‐12‐one and its homologues up to 5α‐cholan‐12‐one were synthesized, partly by breaking down the 17β‐side chain of 5α‐pregnan‐12,20‐dione 12‐ethylene acetal 7 and partly by means of Wittig condensation reactions. They were all characterized by their spectral properties.
Synthesis of NAD+ Analogs. Part II. Synthesis and Anomeric Separation of 3‐Benzoylpyridine Nucleotide
Authors: Winné C. H. R. , Dommisse R. A. , Lepoivre A. J. , Alderweireldt F. C.
Published: September 2010

The title compound is synthesized from the corresponding 2′,3′‐O‐isopropylidene nucleoside with POCl3 in trimethylphosphate. The anomers are separated by preparative HPLC.
1H And 1 3C NMR of some mercaptopyridine and pyridinethione carboxylic acids
Authors: Schanck A. , Dereppe J. M. , van Meerssche M.
Published: September 2010

Proton and carbon‐13 NMR data are presented for positional isomers of mercapto‐pyridine carboxylic acids.

A tautomerism effect is observed for 2‐and 4‐mercapto‐pyridine derivatives.
Spectres RMN‐13C de β‐Aminothiols Disulfures et Thiazolidines Derivés de la Thioephedrine
Authors: Kone B. , Gelbcke M.
Published: September 2010

The carbon‐13 NMR spectra of β‐aminothiols and disulfides related to nor‐and pseudonorthiophedrine (N‐CH3; N‐C2H5; N‐iC3H7 and N‐tC4H9) and the series of the corresponding thiazolidine from paraformaldehyde were obtained. Their study allowed the differentiation of the diastereomers in these three series.
Organometallics, part VII. The synthesis of α,α‐disubstituted methyl ethers by reaction of ethyldiphenylorthoformate with organomagnesium compounds
Authors: Poncini L.
Published: September 2010

The reaction conditions are investigated for the production of pure α,α‐disubstituted methyl ethers. Crotyl‐and ethyl‐magnesium bromides on reaction with ethyldiphenylorthoformate in ether, under reflux conditions, yielded mixtures of mono‐and disubstituted ethers; the former with total allylic transposition. Crotyl Grignard, at room temperature, gave only the monosubstituted mixed acetal. Acetylenic organomagnesiums produced high yields of pure α,α‐disubstituted methyl ethers when the solvent was dichloromethane. Methyl vinyl and isopropenyl vinyl organomagnesiums in THF gave only disubstituted ethers. The products obtained are rationalized in terms of a mechanism incorporating a two‐fold nucleophilic attack on the ethoxyphenoxycarbonium ion formed from the orthoformate by the organometallic anion, displacing two phenoxy groups to yield the α,α‐disubstituted methyl ethers.
The catalytic decomposition of formic acid into carbon monoxide
Authors: Malinowski Marek , Malinowska Krystyna , Zatorski Leon Wiesław
Published: September 2010

Decomposition of formic acid has been studied at 250°‐400°C on some heterogeneous catalysts. Alumina, silica, natural (clinoptilolite) and synthetic (3A, ZSM‐5) zeolites were used as catalysts. H‐ZSM‐5 mixed with γ‐alumina has been found to be the very good catalyst to prepare pure carbon monoxide in a laboratory practice.
The unusual rearrangement of N‐nitroso‐N,O‐dibenzylhydroxylamines with acetic anhydride
Authors: Kano Kunio , Anselme Jean‐Pierre
Published: September 2010

Treatment of N‐nitroso‐N,O‐dibenzylhydroxylamine (2a) with acetic anhydride in benzene at reflux results in a remarkable rearrangement to 2‐benzoyl‐1‐acetylbenzylhydrazine and it was established that it is the N‐benzyl substituent of 2a that is transformed into the benzoyl group of the rearranged product (3a).
The crystal structure of racemic sodium‐hydrogen‐1‐malate
Authors: Doesburg M. M. , Lenstra A. T. H.
Published: September 2010

Na+C4H5O5− crystallizes in the monoclinic space group Pa with Z=4. The unit cell is given by a=10.074(4)Å, b=6.032(2)Å, c=10.338(4)Å and β=120.11(2)°. The OOC‐CH2‐CHOH‐COO chain has the gauche conformation in contrast to the trans conformation observed in the ammonium‐and potassium‐(dl)‐hydrogen‐malates.
A New electrochemical access to unsymmetrical γdiketones via the corresponding γbisdioxolanes. Application to the synthesis of dihydrojasmone
Authors: Bacquet‐Einhorn Cathy , Soulier Jean‐Louis , Lelandais Daniel
Published: September 2010

Summary: A series of unsymmetrical γ bisdioxolanes has been prepared by a mixed coupling of the Kolbe's radicals obtained by anodic oxidation of mixtures of two dioxolanes of γ ketoacids.
The Conformation and Charge Distribution in the Hydrogen Bonded Chelate Ring of Mannich Bases
Authors: Koll A.
Published: September 2010

The dipole moment of 17 Mannich bases has been measured for a broad range of the intramolecular hydrogen bond strength. The increase of the dipole moment caused by the hydrogen bond formation has been calculated and is discussed in terms of the proton transfer equilibrium.

The conformation of the chelate ring was analyzed by means of the atom‐atom and Lippincott‐Schroeder potentials. The calculations predict a nonplanar structure for both the molecular hydrogen bonded form and the zwitterionic proton transfer form. The correlation between the chelate ring structure and the hydrogen bond strength is discussed.
Temperature Dependence of the Dipole Moment of Mannich Bases with An Intramolecular Hydrogen Bond
Authors: Rospenk M. , Koll A.
Published: September 2010

The dipole moments of Mannich bases with an intramolecular hydrogen bond have been measured as function of temperature. For two compounds where proton transfer is apparent in benzene from UV‐VIS spectra, a distinct decrease of dipole moment with increasing temperature has been observed. The dipole moments and their temperature dependence have been analyzed in terms of a tautomeric equilibrium related to the proton transfer within the bridge. It is shown that the quantitative description of the proton transfer process obtained by UV‐spectroscopy is completely valid in the interpretation of the dielectric behavior.
Polarographic Behaviour of Some Arylidene Salicylichydrazides in Solutions of Varying PH at the Dropping Mercury Electrode
Authors: Temerk Y. M. , Kamal M. M. , Ahmed Z. A.
Published: September 2010

The polarographic reduction of some arylidene salicylichydrazides at a dropping mercury electrode was studied in universal buffer solutions containing 40 % ethanol. The mechanism of the electrode processes corresponding to the observed cathodic wave is reported. The effect of substituent group on the half‐wave potential has also been discussed. The values of the kinetic parameters for the electrode reaction at different pH values are computed using the Koutecky and Delahay equations.
Études Structurales en Relation Avec le Concept de Substitution “Capto‐Dative” II. Analyse des déformations moléculaires dans cinq déhydrodimères de formule générale: RCH2 (CN) (SR') C‐C (CN) (SR') CH2R(1, 2)
Authors: Parfonry A. , Tinant B. , Declercq J. P. , van Meerssche M.
Published: September 2010

The crystal structures of five 1,4‐butanedinitrile derivatives have been determined using X‐Ray diffractometry in order to study the effects of captodative substitution on molecular geometry. (I) meso 2,3‐diacetonyl‐2,3‐bis (tert‐butylthio)‐1,4‐butanedinitrile, C18H28N2O2S2, is monoclinic, P21/c with a = 9.694(6), b = 10.208(4), c = 10.404(4) Å, β = 97.46(4) º, V = 1020.8(8)Å3, Z = 2. (II) meso 2,3‐bis[(acetylthio)methyl]‐2,3‐bis(tert‐butylthio)‐1,4‐butanedinitrile, C18H28N2O2S4, is triclinic, PI, with a = 12.867(4), b = 11.175(3), c = 10.430(2)Å, α = 90.43(2), β = 54.82(2), γ = 103.61(2) º, V = 1175.8(6)Å3, Z = 2. (III) meso 2,3‐bis(tert‐butylthio)‐2,3‐bis(butyrylmethyl)‐1,4‐butanedinitrile, C22H36N2O2S2 is monoclinic, C2/c, with a = 22.562(6), b = 10.932(4), c = 10.157(4)Å, β = 90.35(4) º, V = 2505.2(8)Å3, Z = 4. (IV) meso 2,3‐bis (tert‐butylthio)‐2,3‐diethyl‐l,4‐butanedinitrile, C16H28N2S2, is monoclinic, P21/n, with a = 10.004(2), b = 13.794(2), c = 6.633(1)Å, β = 95.61(2) º, V= 910.9(3)Å3 Z = 2. (V) dl 2,3‐diacetonyl‐2,3‐bis(methylthio)‐1,4‐butanedinitrile, C12H16N2O2S2, is triclinic, P1, with a = 9.347(3), b = 9.646(1), c = 8.318(2)Å, α = 99.70(2), β = 104.65(2), γ = 99.23(2) º, V = 698.8(3)Å3, Z = 2.

The central carbon carbon bond lengths are very long in the five molecules. Mean C‐C distance is 1.593(2)Å. Bond angles around central carbon atom take values between 105 and 115°.
119SN‐NMR Spectra of triphenyltin compounds
Authors: Gielen Marcel
Published: September 2010

The 119Sn chemical shifts of fourteen triphenyltin compounds RSnPh3 are reported and discussed.
Produits Lourds Insaturés de la Radiolyse du Diméthyl‐2,3 Butane en Phase Solide III. Processus Ioniques
Authors: Tilquin B. , Bombaert‐Michielsen C.
Published: September 2010

The γ‐radiolysis of solid solutions of N2O, Ar, and CCl4 in 2,3 dimethylbutane has been examined at 77 K. With N2O and Ar, no significant changes in yields of the unsaturated heavy products are produced, however, the yield of the major products (deshydrodimer) was increased. With CCl4, yields of the heavy products were all reduced.

In the case of N2O on Ar as solutes, the results show that ionic mechanism does not produce unsaturated heavy products, by contrast the radical cation does produce at least one of the deshydrodimers.
Study of the mesomorphic behaviour of ternary mixtures of alkoxybenzalazines by means of the Scheffé design
Authors: Marcos M. , Meléndez E. , Serrano J. L. , Mathieu D. , Phan Tan Luu R. , Elguero J.
Published: September 2010

The Scheffé design was applied to a ternary mixture of 4,4′‐diethoxy‐2,2′‐dihydroxy‐α,α‐dimethylbenzalazine, 4,4′‐dipropoxy‐2,2′‐dihydroxy‐α,α'‐dimethylbenzalazine and 4,4′‐dibutoxy‐2,2′‐dihydroxy‐α,α‐dimethylbenzalazine in order to improve the physical properties of each individual component. Twenty‐two different mixtures were selected and their thermodynamical properties measured. A third order model was chosen to account for the experimental measurements. Thus, it was possible to determine the best region in the ternary diagram.
Etudes Structurales en Relation Avec le Concept de Substitution “Capto‐Dative” III. Structures de Cinq Dehydrodimères de Formule R1R2CH‐CHR2R1
Authors: Parfonry A. , Tinant B. , Declercq J. P. , van Meerssche M.
Published: September 2010

From X‐ray diffractometry molecular structure of five 2,3‐bis(disubstituted)‐butanedinitrile or‐dimethylsuccinate have been determined. The aim of this study is to analyse the effects of capto‐dative substitution on molecular deformation in compounds with tertiary central carbon atoms. (I) meso 2,3‐bis (dimethylamino) butanedinitrile, C8H14N4 is monoclinic, P21/α with α=10.545(5), b=6.314(2), c=7.943(3)Å, B=109.25(3)°, V=499.3(3)A3, Z=2. (II) meso 2,3‐bis(methylthio) dimethylsuccinate, C8H14S2O4, is triclinic, P1 with α=8.349(2), b=5.761(1), c=7.928(2)Å, α=71.85(2), β=113.12(2), γ=74.41 (2)°, V=298.0(1)Å3, Z=1. (III) dl 2,3‐bis(phenylthio)dimethylsuccinate, C18H18S2O4, is orthorhombic, Pbnb with α=15.265(3), b=16.618(4), c=7.063(2)Å, V=1791.7(6)Å3, Z1 (III) dl 2,3‐diphenoxy dimethylsuccinate, C18H18O6 is orthorhombic, Pcab with α=21.612(6), b=17.662(4), c=9.029(2)Å, V=3446.5(6)Å3, Z=8. (V) dl 2,3‐diacetoxy dimethylsuccinate, C18H14O8, is orthorhombic, Pca21, with α=10.879(2), b=13.558(2), α=9.133(2)Å, V=1347.1(5)Å3, Z=4.

The geometry of the five molecules is quite normal. These results are compared with those concerning dimers with quaternary central carbon atoms (R1R2R3C)2 in which a long central C‐C bond was found.
Dichloro [1,5‐diphenylcarbazonato‐N,N′]dimercury (II), C13H10N4OHg2Cl2
Authors: Blaton N. M. , Peeters O. M. , De Ranter C. J.
Published: September 2010

C13H10N4OHg2Cl2 is orthorhombic, Pnab with Z=4, a=7.775(1), b=10.375 (1), c=20.117(3)Å, V=1622.8(3)Å3, Dm=2.95, Dc=2.91 Mg m−3, F(000)=1272, μ(CuKα)=39.12 mm−1, Mr=710.34, R=0.114 for 1173 independent reflections.

π‐Electron delocalisation in the Ph‐N‐N‐C‐N‐N‐Ph chain, as was found in the structurally related dithizone molecule, does not occur but a localised single bond for C(Ph)‐N and a localised double bond for N‐N show up. Each mercury atom, sandwiched between the planes of two benzene rings, forms an almost linear bond with a nitrogen and a chlorine atom in a digonal characteristic coordination.
Trigallic Acid or Trimeric Gallic Acid
Authors: Delahaye P. , De Bruyn A. , van Damme F. , Verzele M.
Published: September 2010

Trigallic acid was isolated by Counter Current Distribution from a partial acid hydrolysate of Chinese tannic acid. Trigallic acid in polar solvents solution occurs in four isomeric forms. This is revealed by the four peaks obtained with reversed phase high performance liquid chromatography. Their ratio is function of the solvent. The four isomeric trigallic acid forms are in equilibrium. They result from the meta‐meta, meta‐para, para‐meta and para‐para coupling of the three gallic acid building blocks in trigallic acid. This was proved by spectroscopic and chemical methods.
Mono‐and bi‐nuclear metal complexes of the Schiff bases, arylidenes‐anthranilic acid
Authors: Mahmoud M. R. , Hamed M. M. A. , Youssef M. S. K. , El‐Gyar S. A.
Published: September 2010

Schiff bases, arylidenes‐anthranilic acid complexes with Th(IV), UO2(II), La(III), Ce(III) and Zr(IV) have been isolated. The structure of the complexes is recognized by elemental analysis, electronic spectra and i.r. spectral data as well as conductance measurements. The salicylidene‐anthranilic acid L3 is coordinated to the metal ion as bivalent tridentate ONO ligand (L−2) while the other compounds studied are coordinated to the metal ion as monovalent bidentate ON ligand. The molecular structure effect of these compounds on the strength of their complexes is discussed.

It is identified that the Cu(II) complex of L3 can act as bidentate ligand, coordinating through its cis oxygen atoms to form binuclear metal complexes.
Carbon‐13 nuclear magnetic resonance spectra of some 12‐keto steroids and related compounds
Authors: Biesemans M. , van De Woude G.
Published: September 2010

The 13C magnetic resonance spectra of fifteen 12‐keto steroids, ten corresponding ethylene acetals and seven related 12‐unsubstituted steroids have been assigned.

Substituent effects are analyzed separately and deviations from additivity for different substituent effects are rationalized in terms of conformational changes and intramolecular interactions.
Enzymatic “in vitro” reduction of ketones Part 10 (1). Study of 3‐Acetylpyridine Adenine Dinucleotide in a Co‐enzyme Recycling System Ethanol‐Ketone‐3‐AcPyAD+‐HLAD
Authors: Lemière Guy L. , Jaco Jan , Merckx Erik M. , Lepoivre Josef A. , Alderweireldt Frank C.
Published: September 2010

The NAD+ analogue 3‐acetylpyridine adenine dinucleotide (3‐AcPyAD+) has been studied in the co‐enzyme recycling system ethanol‐ketone‐3‐AcPyAD+‐HLAD. All reaction parameters are tested in analogous conditions as for the NAD+‐recycling system. The stereospecificity of the new system is investigated for the reduction of 4‐, 3‐ and 2‐alkylcyclohexanones. The new recycling system is kinetically and stereochemically very similar to the NAD+ system, but 3.2 times slower.
A Perturbational Force Field Calculation Explains the Increased Conformational Inversion Barrier of 1α,4α‐Dihydroxy‐cis‐1,2,3,4,4a,5,8,8a‐Octahydronaphthalene
Authors: Vanhee P. , Tavernier D.
Published: September 2010

The Gibbs activation energy for the inversion of the (half‐chair) chair conformers of the title compound has been obtained from dynamic 13C‐NMR: ΔG≠239=44.7 kJ mol−1 (k=0.5). It is thus 3.4 kJ mol−1 higher than for the parent hydrocarbon. This increase is rationalized by a perturbational force field study. The reliability of the perturbational calculation was tested by a comparison of calculated and experimental conformational equilibria in various 1‐ and 2‐oxygenated cis‐decalins.
Complexes of Some N‐Substituted Picolinamides with Pd(II) and Pt(II)
Authors: Perlepes S. P. , Kabanos T. H. A. , Tsangaris J. M.
Published: September 2010

The new complexes Pt(NopyH)2Cl2, Pt(NmpyH)2Cl2, Pt(BpnH2)Cl2·1.5H2O, Pt(Bpn).4H2O and Pd(Bpn).H2O, where NopyHN‐(2‐aminophenyl)pyridine‐2′‐carboxamide, NmpyHN‐(3‐aminophenyl)pyridine‐2′‐carboxamide and BpnH2=N,N′‐bis(2′‐pyridinecarboxamide)‐1,8‐naphthalene, have been prepared. Properties, molar conductance measurements and spectral (d‐d, IR and 1H‐NMR) data are discussed in terms of possible structural types and the nature of the bonding. The deprotonated complexes have N4 square planar coordination, while in the compound Pt(BpnH2)Cl2·1.5H2O the ligand displays an apparent unique trans‐bidentate function. NopyH and NmpyH act as monodentate ligands, bonding through the amino group.
Electron Donor‐Acceptor Complexes of Iodine with Imidazole and Some of its Derivatives
Authors: Mahmoud Refat A. , El‐Samahy Ahmed A. , Rabia Mostafa M.
Published: September 2010

Electron donor‐acceptor complexes of iodine with imidazole and some of its derivatives have been studied spectrophotometrically in chloroform. Equilibrium constants and molar extinction coefficients of the charge‐transfer complexes as well as the thermodynamic properties were computed at different temperatures. From the results obtained it has been concluded that the charge‐transfer complexes formed are of the “n” type and the imidazole molecule presents a single energetically favorable donating site for charge transfer complex interaction (i.e. the unshared pair of electrons on the pyridine‐nitrogen N‐3). Furthermore, the effect of the molecular structure of the investigated compounds have been studied. It is found that the equilibrium constants increase regularly as the electron donating character of the substituent is increased. On the other hand, the equilibrium constants decrease with increasing electron withdrawing character of substituents. This is due to the fact that the electron donating group increases the basicity of the donor molecule while the withdrawing group decreases the basicity of N‐3 in the donor molecule.
Vibrational Spectra of 1,4,5,6‐Tetrahydropyrimidine‐2‐Thione and ‐2‐One
Authors: Shunmugam R. , Sathyanarayana D. N.
Published: September 2010

The infrared and Raman spectra of 1,4,5,6‐tetrahydropyrimidine‐2‐thione (Tpt) and‐2‐one (Tpe) have been measured; polarized infrared spectra of Tpt have also been obtained. An assignment of most of the observed bands has been proposed on the basis of polarized infrared spectra, Raman spectra and analogy with the spectra of related compounds. The polarized infrared spectra of imidazolidine‐2‐thione have also been measured as a model compound for comparison with Tpt.
Chiral SC Liquid Crystal Obtained by mixtures and study of the smectic mixtures using the Scheffé algorithm
Authors: Marcos M. , Meléndez E. , Serrano J. L. , Mathieu D. , Phan Tan Luu R.
Published: September 2010

Binary, ternary and quaternary mixtures of four smectogenic compounds: 4,4′‐didecyloxy‐2,2′‐dihydroxybenzalazine, S‐4′‐decyloxy‐2‐hydroxy‐4‐(2‐methylbutoxy)‐α,α′‐dimethylbenzalazine, 4,4′‐didodecyloxy‐2,2′‐dihydroxy‐α,α′‐dimethylbenzalazine and 2‐hydroxy‐4,4′‐dinonyloxy‐α,α'‐dimethylbenzalazine were studied.

These systems of mixture were studied using the Scheffé algorithm which had proved to be particularly useful in the study of these types of mixture.

Induction of chirality in a SC phase by mixture with compounds optically active was studied.

Numerous transition solid‐solid in mixtures during the melting were obtained and their repetition was verified.
N‐Acylamino Acids and Peptides. VII. Synthesis of Oxygen‐Sensitive N‐Acylglycines (N‐Caffeoylglycine, N‐Protocatechuoylglycine and N‐Galloylglycine) and a N‐Acyldipeptide (N‐Caffeoylglycyl‐L‐Phenylalanine)
Authors: Hanselaer R. , D'Haenens L. , Martens M. , van Nieuwenhuyse H. , van Sumere C. F.
Published: September 2010

The synthesis of N‐caffeoylglycine (6), N‐protocatechuoylglycine (16), N‐galloylglycine (17) and N‐caffeoylglycyl‐L‐phenylalanine (7) by means of the active ester method is described.
Isoxazolines‐Key Intermediates For Syntheses of Some Naturally Occuring Amino Compounds
Authors: Jäger Volker , Grund Hartmut , Buß Volker , Schwab Wilfried , Müller Ingrid , Schohe Rudolf , Franz Roland , Ehrler Rudolf
Published: September 2010

[3+2]‐Cycloaddition of nitrile oxides with alkenes, modification of isoxazoline intermediates, and subsequent cleavage give rise to a variety of functionalized acyclic structures. Each step may be used to diastereoselectively increase the number of chiral centres. Application of this concept to the synthesis of natural amino polyols, amino sugars and hydroxy amino acids is discussed.
New Data About Molecular Structure of β‐Trilaurin
Authors: Gibon V. , Blanpain P. , Norberg B. , Durant F.
Published: September 2010

The X‐ray molecular structure of the ß‐trilaurin has been refined starting from the X‐ray model of ß‐tri‐ll‐bromoundecanoin (1). The interatomic distances and angles have been defined with a precision of 0.01 Å and 0.1° respectively. They are compared with those of the ß‐tricaprin (2). In both compounds, we observe a chair‐conformation for the molecule with all the hydrocarbon chains which lie in parallel plans.
The Influence of PH on the Stability of N‐Chloro‐2‐Ethylaminoethanol
Authors: Antelo J. M. , Arce F. , Casado J. , Castro R. , Sanchez M. E. , Varela A.
Published: September 2010

Studying the kinetic behaviour of the system 2‐ethylaminoethanol+hypochlorite under various experimental conditions shows that the rapid formation of N‐chloro‐2‐ethylaminoethanol (t1/2 <1 min) is followed by its slower decomposition, the exact rate of decomposition depending on the pH of the medium. N‐chloro‐2‐ethylaminoethanol is most stable in the range pH 4.5–7.0, where its half‐life is approximately 12.0 days at 25°C.
Pyridines. XI1 ‐ Acidité Relative Des Hydrogènes Des Méthyles de La S‐Collidine Dans L'Éther Diéthylique et L'Ammoniac Liquide
Authors: Compagnon Paul‐Louis , Kimny Tan , Compagnon Odette
Published: September 2010

The adicity of methyl bonded to pyridine nucleus of the s‐collidine depends on the solvent and the counterion nature. With Li+ or Na+ cations in Et2O, we have observed the decreasing acidity order: NH3 > Me‐2 > o‐tolunitrile > Me‐4; with Li+ or Na+ in liquid NH3: o‐tolunitrile > Me‐4 > NH3 > Me‐2. On the other hand, with K+ in Et2O or in liquid NH3: Me‐4 Me‐2 > NH3. An estimate for the pKa value of the s‐collidine (4‐methyl group) is ∼︁∼29 at –33°C in liquid NH3, with Na+ as counterion.
Dipole Moments of Hydrogen Bonded Adducts of Oxygen Bases with 2,6‐Dichloro‐Phenols
Authors: Wolny R. , Koll A. , Sobczyk L.
Published: September 2010

The dipole moments of 30 complexes of oxygen bases with various 2, 6‐dichlorophenols have been measured. The range of ΔpKa = (pKa (BH+) ‐ pKa(AH)) of the complexes varies from ‐9 to +2. The calculated values of the hydrogen bond polarity Δμ have been correlated with ΔpKa based on the Huyskens and Zeegers‐Huyskens proton transfer equilibrium model. Considerably high values of ΔμHB (with no proton transfer), and a small ΔpKa value of the inversion point, at which an equal population of non‐proton‐transfer and proton‐transfer states takes place, are characteristic for the systems studied.
A DC Polarographic Study of Dysprosium(III)
Authors: Bogaert M. , Kiekens P. , Temmerman E.
Published: September 2010

A study of the DC polarographic behaviour of the lanthanide ion dysprosium(III) in an aqueous solution of 0.1 M N(CH3) 4ClO4 has been made. At the very negative potentials where the reduction of Dy(III) takes place, there are several difficulties in the polarographic experiments. Multiple waves are observed, which are associated with the presence of different hydroxycomplexes at the electrode surface.
Investigations Cinétiques Sur L'Oxydation Électrochimique Du Méthanol Sur Une Surface Non Renouvelée et Continuellement Renouvelée D'Une Électrode De Platine
Authors: Vassileva‐Dimova M. P. , Ivanov I. P. , Noninski Ch. I.
Published: September 2010

A coneshaped self‐cleaning rotating electrode (1,2) was used for the investigation of the electrochemical oxidation of methanol in a 0.5 M CH3OH+0.5 M H2SO4 upon an unchanged and continuously renewed surface of a platinum electrode. It was shown that the increase of the speed of renewal of the electrode surface within the potential range 0.50 − 1.60 V leads to a significant increase of the rate of methanol oxidation. It was found that the shape of the i‐y curves obtained during the oxidation of methanol upon a continuously renewed surface differs from the shape of the same curves upon unchanged electrode surface. The observed current maximums at 0.05, 0.85 and 1.35 V upon unrenewed surface have tendency towards disappearing at high rotation speed. A tendency towards disappearing of current maximums is also observed in solutions of methanol when some halide ions are present.
Vibrational Spectra of Pyrimidine‐2‐Thione and Pyrimidine‐2‐Selone
Authors: Shunmugam R. , Sathyanarayana D. N.
Published: September 2010

The synthesis and characterization of pyrimidine‐2‐selone (pymse) is reported. The infrared spectra of pymse and its corresponding sulfur compound namely, pyrimidine‐2‐thione (pymt) have been measured. The Raman spectrum of pymt and the infrared spectra of S‐methyl and N‐deuterated compounds of pymt have been recorded. The fundamental frequencies for these compounds have been assigned and the spectra of pymse and pymt compared. Correlation of the vibrational assignments with those of related molecules have been pointed out.
Acid Catalyzed Rearrangement of Hederagenin
Authors: Singh Anil K. , Dhar Durga N.
Published: September 2010

Hederagenin on treatment with concentrated sulphuric acid at −5–0°C underwent a rearrangement leading to the formation of a new triterpenoidal skeleton, 3‐isopropylidene‐A‐nor‐5‐β‐methyl‐Δ910‐oleanenolactone.
Cyclopolymerization and Conformation of Dimethacrylamides in Polymer Matrices
Authors: Jakus Catherine , Smets Georges , Zeegers‐Huyskens Thérèse
Published: September 2010

N‐phenyl (PDMA) and N‐methyl (MDMA) dimethacrylamide and unsubstituted dimethacrylamide (DMA) have been polymerized in polyvinylchloride film, and the resulting polymers and oligomers were analyzed by infrared and 1H‐NMR spectrometry. The structure of poly (PDMA) and poly (MDMA) corresponds to five‐membered recurring units without unsaturated side groups. On the contrary poly (DMA) contains both five‐ and six‐membered rings as well as some unsaturation. The structures are however identical to those of the corresponding polymers prepared in benzene solution. Consequently the reaction medium does not affect the cyclopolymerization of these dimethacrylamides. A further infrared analysis of the monomers in solution and in the solid state (KBr pellets and PVC films) suggests that the monomers preexist already in a conformation suitable for cyclopolymerization.
Glycosidase Catalyzed Transfer Reactions
Authors: van Opstal O. , De Bruyne C. K.
Published: September 2010

A general reaction scheme for glycosidase catalyzed hydrolyses, proceeding via a two‐phase reaction, is presented. It explains, on the basis of some simple assumptions, transfer to nucleophiles other than water, selftransfer and substrateinhibition. Steady‐state rate equations are derived. Their practical use and mechanistic meaning is discussed.
Bicyclic Isomerization Products of Humulone
Authors: van De Velde M. , De Keukeleire D. , De Bruyn A. , Verzele M.
Published: September 2010

The humulone isomerization mixture is investigated by means of efficient preparative High Performance Liquid Chromatography. New bicyclic humulone isomers are isolated and identified (8 and 10 in FIG. 1).
A Simple Preparation of Pure 2‐Thiothiazolidine‐4‐Carboxylic Acid (TTCA) as a Reference Standard for Carbon Disulfide Exposure Tests
Authors: Kopecký J. , Smejkal J.
Published: September 2010

A simple synthesis and purification of 2‐thiothiazolidine‐4‐carboxylic acid is described starting from cystine and carbon disulfide.
Thermodynamics of Multicomponent Electrolyte Solutions IV. Individual Activities in Electrolyte Solutions
Authors: Vilcu Rodica
Published: September 2010

The individual activity coefficients of ions for alkaline halides in the binary systems LiCl‐H2O; NaCl‐H2O; KCl‐H2O; CsCl‐H2O, and in the ternary systems LiCl‐NaCl‐H2O; LiCl‐KCl‐H2O; LiCl‐CsCl‐H2O; NaCl‐KCl‐H2O are calculated on the basis of the data obtained by cryoscopic measurements. The contribution of the ions to the interaction coefficients of the electrolytes in the solutions studied is determined by means of ion activity coefficients.
The Kinetics of Oxidation of Benzyl Alcohol by Chromic Acid in Two Phase Systems
Authors: Thyrion F. C.
Published: September 2010

The kinetics of oxidation of benzyl alcohol by chromic acid is studied in homogeneous and extractive conditions.

Reaction rates are found to be of the same magnitude when the reaction are localized in aqueous phase or in the organic phase in the presence of a phase‐transfer reagent, although the reactivity seems to be much higher in organic phase.

The mechanism and the effect of the reaction conditions on the rate of the reaction are discussed.
Molecular Structure Determination and Spectroscopic Investigation of {Mn (CO)4 [S‐ (C6H5) 2P‐N (CH3) [CH(CH3) (C6H5)]]}2
Authors: Meunier‐Piret J. , van Meerssche M. , Gielen M. , Vanden Eynde I.
Published: September 2010

Synthesis and molecular structure determination of the title compound are reported. The NMR spectra of {Mn (CO) 4 (C6H5) 2P‐N (CH3) [CH(CH3) (C6H5)] }2 and (Co(CO)3 (C6H5) 2P‐N(CH3) [CH(CH3) (C6H5)]}2 are compared.
Structure de L'Acide Zanhique et de L'Acide Zanhique‐γ‐Lactone, Triterpenoïdes Nouveaux Isoles de Zanha Golugensis et de Ganophyllum Giganteum
Authors: Dimbi Makoso Zeza , Warin Roger , Delaude ClÉMent , Huls Robert
Published: September 2010

Medicagenic acid and two novel triterpenoids, zanhic acid and zanhic acid‐γ‐lactone, have been isolated simultaneously from Zanha golungensis and from Gano‐phyllum giganteum. The structures have been elucidated by spectroscopic means. Zanhic acid is: 2β, 3β, 16α‐trihydroxyolean‐12‐ene, 23,28‐dioic and zanhic acid‐γ‐lactone is: 2β, 3β, 16α, trihydroxy‐oleanane 28:13‐olide‐23‐oïc.
Radicals and Radical Ions Derived from 1,3‐Dienes
Authors: Courtneidge John L. , Davies Alwyn G.
Published: September 2010

Recent improvements in experimental methods have made it possible to generate radicals and radical ions derived from simple 1,3‐dienes, so that their e.s.r. spectra can be observed in fluid solution.

Photolysis of various cyclopentadienylmetallic compounds, or even of pentamethylcyclopentadiene itself, serves as a source of the corresponding cyclopentadienyl radicals, and the former method can be extended to the preparation of the fulvalene and pentalene radical anions.

Cyclobutadiene radical cations are formed when the complexes formed between dimerised dialkylalkynes and aluminium chloride are photolysed. Di‐t‐butyl‐ethyne may also undergo a double nucleophilic rearrangement when it is treated with aluminium chloride, resulting in the formation of the hexamethylbutadiene radical cation, which can also be prepared from hexamethylbutadiene itself.

Radical anions and cations can be regarded as being the conjugate bases and acids, respectively, of neutral radicals, and this principle has been exploited in the generation of cyclopentadiene radical cations from the photolysis of cyclopentadienes in acid solution.
Electrochemical Reduction of M‐Nitrophenol in Buffered Aqueous Solutions
Authors: Heras A. M. , Avila J. L. , Capdevila F. , García Blanco F.
Published: September 2010

A study on the electrochemical reduction of m‐nitrophenol on a mercury electrode in buffered aqueous solutions, has been carried out, focusing on the zone of potentials corresponding to the rising portion of the wave (i/iL<0.05), whose corresponding kinetic parameters allow us to suggest a reduction mechanism for each of the pH‐ranges of 0–1, 1–8.4, 8.4–10.6 and 10.6–13.5.
Studies on Dissociation Equilibria in Water + Dimethylsulphoxide Mixtures and Free Energies of Transfer of Hydrogen Ions
Authors: Deb C. C. , Hazra D. K. , Lahiri S. C.
Published: September 2010

The dissociation constants for the ‘isoelectric’ reactions of the type AH+ · A + H+ (where A = 2,2′‐bipyridine or 1,10‐phenanthroline) have been determined in water + dimethylsulphoxide mixtures (0–90.81 wt% of DMSO) pH‐metrically (using glass and calomel electrodes) and spectrophotometrically. The free energies of transfer of the H+ ion have been calculated. The ΔGto (H+) values have been found to be increasingly negative up to 80 wt% organic solvent indicating that basicity is maximum in this region beyond which the basicity decreases.
Ag(I) ‐ Catalysed Oxidation of Diacetone Alcohol by ce(iv) in H2SO4 Medium
Authors: Nageswar Rao K. , Sondu S. , Sethuram B. , Navaneeth Rao T.
Published: September 2010

The rate of oxidation of diacetone alcohol (DAA) by Ce(IV) in H2SO4 medium increases significantly in the presence of Ag+ ions. The order with respect to [Ce(IV)] is strictly one both in the presence and absence of Ag(I) while the order in [DAA] is fractional in the presence of Ag(I). A mechanism involving the formation of (Ag(I)‐substrate) adduct in the initial step, followed by the reaction with Ce(IV) in the rate determining step to form (Ag(II)‐substrate) adduct which subsequently undergoes internal oxidation to yield the products has been suggested to explain the results. Thermodynamic parameters both in the presence and absence of Ag(I) are also presented and discussed.
Études Structurales En Série Helicenique II. Structure Du (Hydroxy‐1 Éthyl)‐1 Hexahelicene
Authors: van Meerssche M. , Declercq J. P. , Germain G. , Soubrier‐Payen B. , Lindner H. J. , Kitschke Brigitte
Published: September 2010

The crystal and molecular structure of the title compound has been determined by X‐ray diffractometry. The crystal are orthorhombic, space group P212121 with four molecules in the unit cell with dimensions a = 8.541(3), b = 14.100(4), c = 15.812(5)Å. The analysis shows that the compound is the (dl) PR‐MS isomer.
Étude De La Réactivité De Composes Enaminocarbonyles Vis‐À‐Vis De La 1‐Phénylpyrazolidine‐3,5‐Dione.
Authors: Maquestiau A. , Vanden Eynde J.‐J.
Published: September 2010

In acetic acid at room temperature, 3‐amino‐1‐phenyl‐2‐buten‐1‐one, 4‐amino‐3‐penten‐2‐one, various 3‐aminocrotonic esters and amides react with 1‐phenylpyrazolidin‐3,5‐dione to yield compounds resulting from the elimination of ammonia between the two precursors and the so obtained derivatives cyclize on heating to pyrano [2,3‐c] pyrazoles. The rates of these reactions are measured by 1H NMR spectroscopy and mechanistic interpretations are proposed.

Under the same experimental conditions, β‐dicarbonyl compounds are less reactive than the enaminocarbonyl analogues.
Iridoids. Alternative Synthesis of a Key Intermediate for the Synthesis of (±)‐Mussaenoside and (±)‐8‐Epiloganin from 2‐Methoxycarbonyl Tricyclo|3.3.0.02,8|Octanone‐3
Authors: Callant P. , De Wilde H. , Storme P. , Vandewalle M.
Published: September 2010

Starting from 2‐methoxycarbonyl tricyclo|3.3.0.02,8|octanone‐3 (5b) am alternative synthesis of 2‐methoxycarbonyl‐cis‐bicyclo|3.3.0|‐2‐octenone‐6 (9) is reported. 9 has previously been used as an intermediate for (±)‐mussaenoside (3) and (±)‐8‐epiloganin (4).
New Prototropic Processes in the Synthesis of Heterocyclic Compounds
Authors: Grigg R.
Published: September 2010

XYZH systems are considered in general terms and divided into four classes according to the number of constituent atoms that possess lone pair electrons. Those systems in which the central Y atom possesses a lone pair are shown to be capable of participating in formal 1,2‐H shifts generating 1,3‐dipolar species. The scope, regiochemistry and stereochemistry of the cycloadditions of these 1,3‐dipoles is discussed including the relevance of these processes to the biochemistry of pyridoxal enzymes.
NIMO/Al2O3 Catalysts. NI and MO Concentrations Effect. A Comparative Study of Pyridine HDN and Thiophene HDS Reactions on Reduced and Sulfided Catalysts
Authors: Ledoux H. J. , Agostini G. , Benazouz R. , Michaux O.
Published: September 2010

The Ni and Mo concentrations effect on the pyridine HDN and thiophene HDS under normal H2 pressure, on reduced or sulfided classical NiMo/Al2O3 has been studied by comparison of activities and by simultaneous analysis of the selectivity in different products. If the expected promoting effect of Ni for the HDS reaction has been found, the best catalyst for HDN was the pure Mo/Al2O3. It has also been found that the sulfided Mo catalyst is a better hydrogenating system than the reduced oxidic form and the sulfided Ni promoted catalysts. An attemp to explain the promoting effect of Ni on Mo based catalysts is given.