bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiation Chemistry of N‐Hexane Aqueous Solutions as Studied by Chromatographic Analysis of Final Products
Authors: De Doncker J. , Tilquin B.
Published: September 2010

Radiolysis of dilute oxygen‐free hexane aqueous solutions give dodecanes isomers analyzed by capillary gas chromatography. The relative yields for radicals which react by radical‐radical recombination reactions are 39 %, 32 % and 29 % for primary hexyl radical, secondary‐2 hexyl radical and secondary‐3 hexyl radical respectively. This distribution is changed with the N2O saturation before the radiolysis to 22 % 42 % and 37 %. If the first distribution is statistic, the increase of OH available to attack the solute gives the distribution existing in pure alkane radiolysis.
Synthesis and Characterization of Cinnamaldehyde Ferrocene‐Carbonylhydrazone and its Complexes with Lanthanide
Authors: Yong‐xiang Ma , Guo‐sheng Huang , Pei‐song Jin , Xiao‐jun Han
Published: September 2010

A new ligand, cinnamaldehyde ferrocenecarbonylhydrazone, FcCONH‐N = CHCH = CHPh (Cafch) (Fc = η5‐C5H5FeC5H4 and its chelates with lanthanide, Ln(Cafch)3Cl3·O‐4H2O(Ln = Y and lanthanide) have been prepared by the reaction of the Cafch with LnCl3 and characterized by elemental analysis, IR,1H n.m.r., electrolytic conductivities, TG and DSC measurements. In these chelates the ligand coordinates to lanthanide ion in the keto form and the coordination numbers of the central metal ions are probably equal to eight.
Isotope Labelling Studies of Some Aromatic N‐Oxides ‐ Part IV. A Full Vibrational Assignment of the Infrared Spectra (4000‐50 CM−1) of Quinoline N‐Oxide Dihydrate and its Fully Deuterated Analogue
Authors: Thornton David A. , Watkins Gareth M.
Published: September 2010

Full infrared vibrational assignments (4000 to 50 cm−1) of quinoline N‐oxide and its fully deuterated analogue have been made. Coupling within the molecule is examined employing the νD/νH ratio and by comparison with similar molecules.
Recherches En Série Benzodiazepine‐1,5: Synthèses Des Ditriazolo‐[4,3‐a; 3,4‐d]‐Benzodiazepines‐1,5
Authors: Essassi E. M. , Lamkadem A. , Zniber R.
Published: September 2010

The action of several o‐phenylenediamines on malonic acide was studied. Six, new dítriazolo‐[4,3‐a; 3,4‐d]‐1,5‐ benzodiazepines were prepared from 1,5‐benzodiazepin 2,4‐diones‐Their structures are supported by 1H nmr, ir, mass spectrometry and elemental analysis
Benzylation of 1‐Benzylidene‐3‐Pyrazolidinium Oxides
Authors: Dowling† James E. , Anselme J.‐P.
Published: September 2010

The benzylation of 1‐benzylidene‐5‐phenyl‐3‐pyrazolidinium oxide (2a) gives five products including the “head to head” dimer of 2 (7) and the ring‐opened 1‐benzyl‐1‐cinnamoylbenzalhydrazone (4a). Similar behavior was also observed with ylides bearing various substituents at the 4 and 5 positions.
Reductive Coupling of Benzoic Acid Halides and Esters Using Low‐Valent Titanium
Authors: Dang Y. , Geise H. J.
Published: September 2010

The reductive coupling of (substituted) benzoic acid chlorides and esters is achieved using low‐valent titanium, generated from TiCl3 and LiAlH4. Both acid chlorides and esters seem to follow the same two reaction pathways: one path via tolanes to stilbenes, the other via benzils to complex mixtures of products arising from reduction and further coupling reactions. Although the exact product balance depends upon the reaction conditions the major product is (substituted) cis‐stilbene.
Synthesis and Biological Activities of Bradykinin Analogues with Ψ(E,CH=CH) and Ψ(CH2‐NH) Isosteric Peptide Bond Replacements
Authors: Scarso A. , Degelaen J. , Viville R. , De Cock E. , van Marsenille M. , van Der Auwera L. , Tourwé D. , van Binst G.
Published: September 2010

The synthesis of bradykinin analogues is described in which the Gly4‐Phe5, Phe5‐Ser6 or the Pro7‐Phe8 peptide bond has been replaced by a trans carbon‐carbon double bond or by a “reduced” peptide bond. Some of the analogues display high potency and prolonged activity in the rat blood pressure test, indicating increased metabolic stability. A clear selectivity is obtained towards the myotropic effect in the guinea pig ileum.
Spectres de Masse FAB en Mode Positif de Cations Hétérocycliques Doublement Charges Apparentes au Dibenzo[a,e]Cyclooctane
Authors: Aubagnac Jean‐Louis , Claramunt Rosa‐Maria , Lavandera José‐Luis , Elguero José
Published: September 2010

FAB mass spectra in positive mode of doubly charged heterocyclic cations allow identification of such structures. Furthermore, two characteristics of these spectra (low abundance of the doubly charged cations and the reduction phenomenon) are in agreement with previous results.
Synthèse et Identification des 4‐OXO‐1,4‐Dihydropyrimidines en vue des Applications Pharmacologiques
Authors: Védernikova I. V. , Ryabukhin Yu. I. , Haitin M. I. , Simkina Yu. N.
Published: September 2010

There is described synthesis of 2,6‐dimethyl‐5‐phenyl‐4‐oxo‐1,4‐dihydropyrimidines and their perchlorates with phenolic or acetoxyphenolic substituent in the 1st position.

All these compounds possess activities as tranquilizers and antidepressive and neuroleptic geants.
Novel Platinum(II)‐Diaminobiotin Complexes. Their Synthesis and Characterisation
Authors: Noels A. F. , Nihant N. , Hubert A. J.
Published: September 2010

The diaminobiotin ligand 1 (cis‐3, 4‐diamino‐2‐tetrahydrothiophene valeric acid) was reacted with potassium chloroplatinate and with diaquodiammine platinum(II) cation 3 to yield new platinum complexes which were coordinated in a bidentate fashion through the diamine function of the ligand and have [PtN2Cl2] and [PtN4] geometries respectively.
Nouveaux Décontaminants. Action des Péracides à Groupe Ester sur Quelques Toxiques Insecticides ou de Guerre
Authors: Lion C. , Hedayatullah M. , Bauer P. , Boukou‐Poba J. P. , Charvy C. , Delmas G. , Magnaud G. , Fosset L. , Despagne B. , Sentenac‐Roumanou H.
Published: September 2010

A new peroxyacid‐ester series has been obtained and used in the destruction of toxic agents. These structures oROCOC6H4CO3H and ROCO(CH2)nCO3H are more stable than the unsubstituted compounds. The reaction with paraoxon (0,0‐diethyl 0‐paranitrophenylphosphate) and HD (2,2′‐dichlorodiethylsulfide) goes to completion in a very short time. The influence of the R group and the length of the chain (n = 2……12) has been studied. The addition of some long chain tetraalkyl‐ammonium salts enhances the rate of the reaction by micellar catalysis.
An Analysis of Substituent Effects on the Proton and Carbon‐13 Chemical Shifts of 9‐Chloro and 9‐Amino Acridines
Authors: Faure Robert , Galzy Jean‐Pierre , Barbe Jacques , Boukir Abdel Lhatif , Vincent Emile‐Jean , Boyer Gérard , Elguero José
Published: September 2010

The 1H chemical shifts, 1H‐1H coupling constants, 13C chemical shifts, and some 1H‐13C and 13C‐19F coupling constants have been determined for seven 3‐substituted‐9‐chloroacridines and for the corresponding 3‐substituted‐9‐aminoacridines. The effects produced by the substituent in position 3 on the 1H and 13C chemical shifts are discussed using two empirical models, those of Smith and Proulx (F, R, Q*) and Reynolds (σF, σR0, I, O, M).
Unexpected Internal Peptide Butoxycarbonylation of a Linear N‐Me Amide Peptide Derived from Virginiamycin S and Resulting Failure for a Carboxy‐Terminal Sequencing. Preparation of the Tetrapeptide Synthon Thr‐D‐Abu‐Pro‐MePhe‐OBzl
Authors: Moerman Marc C. , Anteunis Marc J.O.
Published: September 2010

Next to the preferential butoxycarbonylation of the picolinic hydroxyl group in Virginiamycin S1 (1a) and of VS‐fragments derived therefrom, a second Boc‐group is invariably and specifically implanted at the proximate amide bond preceding Thr (residue 1 in 1a). This exclusive predisposition for the introduction of a second Boc‐group has prevented the accomplishment of a programmed reaction sequence (SCHEME I) that should have led to the preparation of a VS congener, lacking the N‐methyl at position 1 (des‐4MeVS; 1c). On the other hand this predestined “Boc‐ation” at Thr‐NH can be exploited for the removal of the picolinic residue. This possibility has been tested in the succesful five step preparation of a tetrapeptide ester Thr‐D‐Abu‐Pro‐D, L‐MePhe‐OBzl (SCHEME II) starting from natural VS1.
Synthesis of a New Series of Enkaphalin Related Galactosyl Conjugates
Authors: Vansteenkiste Stefan , Schacht Etienne , Haro Isabel , Reig Francesca , Parente Antonio , Garcia‐Anton Jose Maria
Published: September 2010

(D‐Met2,Pro5)‐enkephalin‐N‐(β‐D‐galactopyranosyl)amide, a glycopeptide containing a galactose residue at the C‐terminal position of the μ‐selective enkaphalin analogue (D‐Met2,Pro5)‐enkaphalinamide, has been synthesized by the liquid phase procedure according to different strategies. Such analogue exhibited a great antinociceptive potency after intracerebroventricular injection in the “in vivo” tail immersion test when compared to the parent compound and the corresponding glucose derivative. Therefore, we suggest that the opioid receptors mediating analgesia, interact more efficiently with galactosyl rather than glucosyl residues. To confirm this hypothesis, we have synthesized a series of galactosyl conjugated (D‐Met2,Pro5)‐enkaphalins, containing up to three galactose residues linked to the oligopeptide backbone throughout a hydrophobic carbon c‐6 spacer.
A Scanning Tunneling Microscopial (STM) Study of (NH4)2[Mo3S13] · H2O and its Thermal Decomposition Product MoS2
Authors: Diemann E. , Branding A. , Müller A.
Published: September 2010

The LDOS of films of (NH4)2[Mos3S13] · H2O on carbon supports have been studied with positive and negative bias voltage in the scanning tunneling electron microscope. The obtained pictures can be assigned to LUMO and HOMO states formed by the cluster anions, respectively. An important result is that the Mo3 planes are always found perpendicular to the support. This orientation is essentially retained when the film of the cluster compound is thermally decomposed to MoS2.
Etude Des Reactions De Coupure Des Liaisons O‐Si(CH3)3 Dans Des Polystyrenes Silicies En Presence De Sels De Triphenylsulfonium Avec Ou Sans Perylene Sous Irradiation UV Et Visible Et En Couche Mince
Authors: Madit N. , Giral L. , Montginoul C. , Sagnes R. , Schué F. , Rosilio C. , Guibert J. C.
Published: September 2010

This paper describes a positive resist formulation containing silylated polystyrene polymer, made photosensitive at wavelengths from 220 to 310 nm by means of an onium salt sensitizer ((C6H5)3SMXn) and at wavelengths from 360 to 450 nm by means of an onium salt and a dye photosensitizer (perylene). In the present study, we report the desilylation of acid‐sensitive polymers as poly (4‐trimethylsiloxystyrene) or poly [p‐trimethylsiloxystyrene‐co‐p‐(tert‐butoxycarbonyl) oxystyrene]. The formed Brönsted acid which induces the cleavage of silicon ‐ containing side groups is HMXn. The transformation reaction is followed by IR spectroscopy before and after exposure. This resist system is resistant to etching in an oxygen plasma.
Ring Transformations of Pyrazolones Via Azo‐Olefins
Authors: Schmitz Ernst , Lutze Gerhard , Kirschke Klaus , Hübner Petra
Published: September 2010

Instead of substitution, 4‐halo‐pyrazolones undergo ring opening to azo‐olefins (2, 12, 16) on reaction with nucleophiles. Attempted Hofmann degradation of N‐Haloamides 4 has to compete with either ring closure, involving NHCl‐shift to 7, or formation of mesoionic compounds 10, whose pyrazolone ring shows a different pattern of nitrogen insertion. Substitution of cyclic amines for chlorine in azo‐olefin 12 is followed by rearrangement to the bicycle 15. Access to 1,2,3‐thiadiazolium salts (18, 22) is possible by electrophilic attack of sulfur reagents to azo‐olefins.
Susceptibilite Electrique Haute‐Frequence De Jonctions Silicium‐Electrolyte
Authors: Ammari M. , Bohnké C. , Bohnké Mme O. , Gire A. , Lomaglio Mme G. , Théobald J.‐G.
Published: September 2010

The electrical susceptibility of the Silicon‐electrolyte interface has been studied when the electrical irradiation field is parallel to the junction. In the High Frequency (H.F.) range, the absorption exhibits one maximum depending on the voltage applied between the semi‐conductor and the electrolyte. This drastic variation, specially the maximum, is at our opinion, due to the minority carriers. It is modified by irradiation. In the microwave range, the maximum of absorption is rather difficult to observe probably because electrochemical reactions occur. The variation of dispersion is negative, we explain that by considering the high frequency local field.
The Use of Thermal Analysis for the Study of the Calcinationprocess of Oxalateprecursors for the Synthesis of High Tc Superconductors
Authors: Vos A. , Mullens J. , Carleer R. , Yperman J. , Vanhees J. , van Poucke L. C.
Published: September 2010

The decomposition of the oxalateprecursors Y2(C2O4)3.4BaC2O4. (6 + n)CuC2O4. xH2O for the synthesis of high Tc superconductors and the individual Y‐, Ba‐, Cu‐oxalate components is investigated by DTA and by TGA coupled with FTIR.
Novel Syntheses of Heterocycles with N‐(1‐Haloalkyl)Azinium Halides Part 1. Preparation of Imidazolidines
Authors: Vanden Eynde J.‐J. , Mayence A. , Maquestiau A. , Anders E.
Published: September 2010

N‐(1‐Chloroalkyl)pyridinium chlorides, prepared from thionyl chloride, pyridine, and an aldehyde, readily react with N,N′‐disubstituted 1,2‐ethanediamine to yield imidazolidines under mild and neutral conditions.
Nouveaux Decontaminants. Destruction De Toxiques Organophosphores Ou Soufres Par Des Peracides Mono‐, Bi‐ Et Tricycliques Satures
Authors: Lion C. , Hedayatullah M. , Bauer P. , Boukou‐Poba J. P. , Charvy C. , Delmas G. , Magnaud G. , Fosset L. , Despagne B. , Desgranges M. , Sentenac‐Roumanou H.
Published: September 2010

New peroxycarboxyclic and peroxyacetic acids have been tested for the destruction of some organophosphorus compounds and mustards. The peroxyacids used have monocyclic, bicyclic or tricyclic structures. These are very reactive against paraoxon or HD and the addition of certain surfactants enhances the reaction rate. Very short half‐live times are obtained with these compounds.
Synthesis of N‐Hydroxy‐2‐Azetidinones from Oximes
Authors: Mulengi J. Kajima , Fatmi N.
Published: September 2010

The title compounds can be prepared by a direct conversion of unprotected oximes using a Reformatsky reagent and anhydrous AlCl3 or triethylamine.
The Oxidative Degradation of Polystyrene Studied by the Coupling of Thermogravimetry with Other Techniques
Authors: Mullens J. , Carleer R. , Reggers G. , Ruysen M. , Yperman J. , van Poucke L. C.
Published: September 2010

A description is given for the combination of techniques for the study of the oxidative degradation of polystyrene samples with different additives. Thermogravimetry is used for the determination of the degradation profile (weight loss versus temperature). The evolved gases are investigated on‐line by Fourier transform infra‐red spectroscopy. Simultaneously, evolved gases are also collected by an adsorbent and, after the thermal experiment, desorbed to release the volatile products for identification using gaschromatography‐mass spectrometry. The combination of the three techniques offers the unambiguous identification of the gaseous decomposition products as a function of the temperature. The identified products are CO2, H2O, benzene, toluene, xylene and styrene for a first sample; CO2, H2O, toluene, styrene, benzaldehyde and methylstyrene for a sample of a second polystyrene with other additives.
Complexes of the Type R'OOC‐CHR‐CH2SnCl3.OPPh3 Readily Undergo Transesterifications into R”OOC‐CHR‐CH2SnCl3.OPPh3 When Reacted with R”OH
Authors: Fu Fangxin , Li Zhongfang , Tian Laijin , Pan Huade , Kayser François , Willem Rudolph , Gielen Marcel
Published: September 2010

Complexes of 2‐alkoxycarbonylethyltin and 2‐alkoxycarbonyl‐2‐methylethyltin trichlorides, R'O‐CO‐CHR‐CH2SnCl3.OPPh3, readily undergo transesterification reactions into the corresponding alkoxycarbonyl analogs R"OOC‐CHR‐CH2SnCl3.OPPh3 when reacted with R"OH.
High Yield Preparation of 2,3,3‐Trichlorinated Tetrahydropyran with an Excess of Refluxing Sulfuryl Chloride in the Dark
Authors: De Buyck Laurent
Published: September 2010

The chlorination of tetrahydropyran with an excess of refluxing sulfuryl chloride in the dark provided 2,3,3‐trichlorotetrahydropyran in 94% isolated yield, showing evidence for a very selective non‐homolytic mechanism, probably involving hydride abstraction as the first step.
Heteroaromatic Cations as Key Intermediates for the Synthesis of Functionalized Dihydro‐Heteroaromatic Compounds
Authors: Akiba Kin‐Ya
Published: September 2010

N‐Ethoxycarbonylpyridinium chlorideAwas generated in solution (CH2Cl2or CH3CN) from pyridine and ethyl chloroformate and reacted to tri‐i‐propyl phosphite, RCu·BF3, and silyl enol ethers at 4‐position exclusively to afford 1,4‐dihydropyridine derivatives containing the corresponding phosphonyl (2), R (6), and 2‐oxoalkyl (11) groups in high yields. These were oxidized to the corresponding 4‐substituted pyridines by oxygen. Methyl nicotinate was also quaternized by ethyl chloroformate to generate the nicotinium saltDin situand silyl enol ethers and RCu·BF3added at 4‐position exclusively to give 1,4‐dihydronicotinic esters12, 13in high yields.N‐Methoxy‐carbonylquinolinium chlorideEwas generatedin situand reacted to silyl enol ethers to give a mixture of 2‐ and 4‐adducts. The major adducts15, 1,2‐dihydroquinolines having 2‐oxoalkyl group at 2‐position, were easily separated by flash column chromatography. Trialkyl phosphite reacted toEat 2‐position exclusively to give the corresponding 1,2‐dihydroquinoline‐2‐phosphonate16, which was alkylated at 4‐position exclusively after deprotonation byn‐butyllithium.N‐Ethoxycarbonyl‐isoquinolinium chlorideGwas also generatedin situand reacted to silyl enol ethers at 1‐position exclusively to afford the corresponding 1,2‐dihydroisoquinolines20. 20was used as a precursor for stereoselective cyclization to benzo[a]qionolizine derivatives.

Chromone and coumarin reacted neat witht‐BuMe2SiOTf by heating and 4‐ (I) and 2‐(K)‐siloxybenzopyrylium salts were prepared. Both salts reacted with conjugated 2‐siloxydienes and afforded [4+2] type cycloadducts32and37in one‐pot process. The stereochemistry of annulation was cis for all the cycloadducts and the structure of the cycloadducts is discussed in detail based on1H NMR.
From Phosphaalkynes to Phosphacubanes — Adventures in Organophosphorus Chemistry[1]
Authors: Regitz Manfred
Published: September 2010

Phosphaalkynes (4) — readily accessible from carboxylic acid chlorides and tris(trimethylsilyl)phosphane — serve as starting materials for the synthesis of phosphirenes (13, 18, 41, 45). The significance of the 1‐chloro‐2‐phosphirene (18) for the generation of phosphirenylium cations (A⟷B or C) as well as its ring enlargement reaction to 1,2‐dihydro‐1,2‐phosphasilete (28) and its ring cleavage reaction to 1,2,3‐butatrienes (48) and vinylallenes (51) are illustrated. The non‐selective thermal cyclotetramerization of 4 to give, among others, the tetraphosphacubane 56 is compared with a preparative, two‐step procedure starting from the tricyclic zirconium complex 60; the latter process provides higher yields of 56. The phosphorus atoms in the pentacyclic system can be functionalized by a wide range (66–73). In the presence of Lewis acids such as aluminium trichloride, phosphaalkynes (4) undergo spirocyclotrimerization to furnish betaines of the type 77.
Synthetic Applications of N‐Sulfonyl Imines
Authors: Weinreb Steven M.
Published: September 2010

N‐Tosyl imines, prepared from aldehydes and N‐sulfinyl‐p‐toluene sulfonamide (Kresze reaction), cyclize with alkenes and vinyl silanes in the presence of a Lewis acid to afford intermediates useful for alkaloid total synthesis.
The Removal of Water in Organic Reactions Trimethylsilanol as a Leaving Group
Authors: Vorbrüggen Helmut
Published: September 2010

In many synthetic reactions water is formed, which is normally removed by drying agents such as Na2SO4 and molecular sieves or alternatively by azeotropic distillation employing auxiliary solvents such as toluene or xylene.
Action Des Amines Et Des Hydrazines Sur Les Imidates Issus Du Methyl 3‐Amino‐2‐Thiophene Carboxylate. Nouvelle Voie D'Acces Aux [3,2‐d]4(3H)Thienopyrimidinones
Authors: Hajjem B. , Ben Khoud M. L. , Baccar B.
Published: September 2010

Methyl 3‐amino‐2‐thiophene carboxylate reacts with orthoesters to produce N‐(2‐carbomethoxy thienyl) imidates 1. Treatment of these imidates with primary amines, hydrazine, methylhydrazine and phenylhydrazine yields only [3,2‐d]4(3H)thieno‐ pyrimidinones 2 and not isomeric 1,3,4‐thienotriazepin‐5‐ones. The type of products obtained gave information relevant to the elucidation of the mechanism of cyclization and the relative activities of the ester and imidate groups.
Preconcentration and Determination of Traces of Strontium in Natural Waters by Ion‐Exchange and Flame Atomic Absorption Spectrometry
Authors: Yebra‐Biurrun M. C. , Bermejo‐Barrera A. , Bermejo‐Barrera P.
Published: September 2010

A flame atomic‐absorption spectrophotometric method for determining strontium in natural waters is described. The use of ethylenediamine tetraacetic acid (EDTA) to suppress interferences was studied, and ion‐exchange with Amberlite IR‐120 (H+) to concentrate the metal was used; strontium being eluted with 3% EDTA.

The precision and reproducibility of the method were also investigated, and optimum results were obtained. Strontium concentrations for samples analyzed were between 4 and 147 μg/l. The detection limit was 1.6 μg/l, and the sensitivity was 3.2 μg/l for strontium.
Mise En Evidence Par Rmn‐1H Et ‐13C D'Isomerisme Z/E Et D'Equilibre Conformationnel Sur Une Serie De Derives Mono‐ Et Diacetyles De 2‐Alkylamino‐1‐Phenylpropan‐1‐Ols
Authors: Tytgat D. , Gelbcke M.
Published: September 2010

1H‐ and 13C‐NMR studies of mono‐ and diacetylated‐erythro‐ and threo‐2‐alkylamino‐1‐phenylpropan‐1‐ols, C6H5CHOHCHNHRCH3 (R = H, CH3, C2H5 and i‐C3H7) show that the series exhibit Z/E isomerism about the C‐N amide bond. The Z/E ratio increases in the monoacetylated series CH3 < C2H5 < i‐C3H7 indicating that the hydrogen bond between the hydroxylic proton and the carbonyl function of the amide is in the case of the isopropyl substituent favoured. In the diacetylated series, where an hydrogen bond is not possible, the Z/E ratio is respectively in the erythro and threo series about 3 and 1. The progressive increase of the volume of the substituent N‐alkyl modifies the conformational equilibrium about the C1‐C2 and N‐C2 bonds. In the Z configuration, the conformer Z‐s‐syn where the proton H‐2 is syn with the N‐alkyl substituent predominates.
Novel Syntheses of Heterocycles with N‐(1‐Haloalkyl)Azinium Halides. Part 3. Preparation of 2‐Aryl‐1‐Arylimino‐2,3‐Dihydro‐1H‐Isoindoles
Authors: Vanden Eynde J.‐J. , Mayence A. , Maquestiau A. , Anders E.
Published: September 2010

The title compounds can be synthesized readily by reaction of primary aromatic amines with the azinium salt obtained from thionyl chloride, pyridine, and 1,2‐benzenedicarboxaldehyde.
New Low Coordination Phosphorus Heterocycles
Authors: Teunissen Herman T. , Bickelhaupt Friedrich
Published: September 2010

With the aim of synthesizing novel functionalized derivatives of phosphinine (phosphabenzene), we investigated Diels‐Alder approaches to 2‐halophosphinines. The reaction of dienes such as 1‐isopropenyl‐1‐cyclohexene and 1‐vinylnaphthalene with Cl2P‐CHCl2 and triethylamine gave 2‐chlorophosphinines, but their substitution pattern was unsuitable for the synthesis of bidentate phosphinine ligands. However, the precursor Cl2P‐CHl2 reacted with triethylamine in the presence of 1,3‐butadiene or its 2,3‐dimethyl derivative to furnish 2‐iodophosphinines 5 which, directly or after formation of their pentacarbonyltungsten complexes, underwent a number of interesting functionalization reactions. Useful for reaction with a number of electrophiles were the organozinc reagent 4,5‐dimethyl‐2‐iodozincophosphinine (26) which could be obtained directly from the corresponding 2‐iodophosphinine 5b and zinc either in DMF or in THF/TMEDA, and the pentacarbonyltungsten coordinated 2‐lithio derivative 36.
Novel Reactions of Carbohydrates Discovered En Route to Natural Products
Authors: Fraser‐Reid B. , Alonso R. A. , McDevitt R. E. , Venkateswara Rao B. , Vite G. D. , Zottola M. A.
Published: September 2010

An approach to the synthesis of tetrodotoxin is described in which two key reactions are used to establish the densely functionalized carbocyclic ring. The [3:2:1]‐bicyclic framework of 1,6‐anhydro mannopyranose serves as the template, and in the first key reaction, oxazolidine ring formation is used to introduce the angular nitrogen and, simultaneously, to preorganize functional groups for the second key reaction. The latter involves formation of the carbocyclic ring via a radical cyclization process.
Electrochemical Study of CIS‐Dicyanoaquoethylenediamine Nitrosylchromium Complex and its Adducts with Mercury(II) and Silver(I)
Authors: Rievaj Miroslav , Korgová Elena , Bustin Dusan
Published: September 2010

The paper describes electrochemical properties of NO(en)(H2O)Cr(CN)2 and the polarographic investigation of its acid hydrolysis. Stoichiometry (1:1) of NO(en)(H2O)Cr(CN)2 reactions with Hg2+ and Ag+ was determined using potentiometric method. Adducts formed by these reactions were investigated polarographically and linkage isomerisation of bridging cyano ligands has been found to be involved in their formation. Decomposition kinetics of the adduct NO(en)(H2O)Cr(NC)2Hg2+ was studied, factors affecting it discussed and found kinetics data compared with those determined for similar cyano complexes.
Crystal Structure of 1,3,5(10)‐Estratriene‐1,17 β‐Diol 17‐Acetate
Authors: Tinant B. , Declercq J. P. , Rajkovic M. , Petrovic‐Davidovic I. , Lorenc Lj. , Mihailovic M. Lj.
Published: September 2010

Oxidative hydrolysis of N‐methyl‐1β, 5‐epoxyimino‐19‐nor‐5β‐androst‐3‐en‐17β‐ol acetate 1 afforded the title compound 2, the molecular structure of which was determined by the X‐ray diffraction technique. 2 : C20H26O3, Mr=314.42, orthorhombic, P212121, a=9.636(3), b=11.307(5), c=16.096(5)Å, V=1754(1)Å3, Z=4, Dx=1.19g.cm−3, MoKα, λ=0.71069Å, μ=0.84cm−1, F(000)=680, T=291K, R=0.060 for 1211 observed reflections. Ring A is slightly non planar, ring B is a half‐chair and ring C a chair. The 5‐membered ring D has a regular half‐chair conformation.
Another Possible Carbon Allotrope
Authors: Elguero José , Foces‐Foces Concepción , Llamas‐Saiz Antonio L.
Published: September 2010

A new allotropic form of carbon formed by allene units is described. Its tetragonal unit cell contains 12 carbon atoms (8 sp2 and 4 sp) and it has a calculated density of 2.72 g. cm−3. As a result of the mixture of sp2 and sp carbon atoms, this new all‐carbon molecule is expected to be rather stable and may have metallic properties.
On the Mechanism of Selective Chlorination of Ethers with Sulfuryl Chloride in the Dark
Authors: De Buyck Laurent , De Pooter Herman
Published: September 2010

Alkyl 4‐chlorobutyl ethers reacted in the dark with an excess of sulfuryl chloride at 70–85°C (bath) to afford α,β,β‐trichlorinated ethers. The reactions were accelerated 3− to 6‐fold by N,N‐dimethyl‐octylammonium salts (0,12 to 1 mmol/mol ether). This catalyst promoted decomposition of sulfuryl chloride to chlorine and sulfur dioxide and thereby caused serious loss of sulfuryl chloride. The proportions of chlorination at α or α' position were identical in the catalyzed or uncatalyzed version and depended on inductive effects, correlating well with Taft's linear free energy relationship log k/kref = ρ* σ* for R = H, Me, Et, Pr in RCH2O(CH2)4Cl with ρ* = −2.6±0.1. The overall reactivity of ethers appears to vary like the nucleophilicity of the ether oxygen. It is concluded that hydride abstraction occurs indirectly, probably involving a chloroxonium ion pair.
A Convenient Preparation of Pivalaldehyde: Some Remarks on the Bouveault Synthesis
Authors: Nazarski Ryszard B. , Tasz Maciej K. , Skowroński Romuald
Published: September 2010

A simple and versatile procedure of pivalaldehyde synthesis is described. The synthesis is based on the formylation of tert‐butyl magnesium chloride with excess of DMF in low temperature and can be easily performed in bulk scale. The application of DMF for the formylation of tertiary Grignard compounds is briefly discussed in terms of steric effects.
Effet Hall Hyperfréquence Dans Des Semi‐Conducteurs Constituant Des Jonctions
Authors: Ammari M. , Gire A. , Lomaglio Mme G. , Théobald J. G.
Published: September 2010

The resonances at microwave frequencies can be observed in polarized junctions; this was studied in previous papers and we have called for an important contribution of minority carriers. With a magnetic field B, a non diagonal component of the electrical conductivity can exist, a sort of microwave Hall effect. This can be considered as the effect of the non‐diagonal part of the microwave susceptibility along the E ⁁ B direction. We report the observation of this non‐diagonal component, which allows to verify the sign of the charge carriers. This experiment can be considered as a generalization of the d.c. Hall effect.
A Fast Method for Fitting the G Tensor of EPR Powder Spectra Using the Levenberg‐Marquardt Algorithm
Authors: Moens P. D. W. , Naessens D. E. , Callens F. J. , Matthys P. F. A. , Maes F. R. C. , Boesman E. R.
Published: September 2010

A finite difference Levenberg‐Marquardt algorithm is used for optimizing the principal g tensor values of paramagnetic radicals observed in EPR spectra of polycrystalline materials. A special method is presented to select a small number of data points which are assumed to be representative for the entire EPR powder spectrum. Thus, the spectrum has only to be calculated in a small number of points resulting in a drastic reduction of the computer time. The method is demonstrated on two simulated EPR powder spectra and one experimentally recorded spectrum of X‐irradiated powdered human tooth enamel.
Basicite De L'Hydroxyde De Tetrabutylammonium En Milieu Acetonitrile Eau
Authors: Borghese A. , Laurent F. , Tondeur J.‐J. , Vandendunghen G.
Published: September 2010

The acidity function H. of tetrabutylammonium hydroxide in aqueous acetonitrile has been evaluated by use of Hammett indicators in the range of molar fractions in water lying between 0.05 and 0.65. The results are correlated with the available data concerning the structure of these mixtures.
Synthese Und Antitumoraktivität Von Platin(II)‐Komplexen Mit Cholesterinderivaten
Authors: Brunner H. , Sperl G.
Published: September 2010

Low‐density‐lipoprotein‐receptor binding moieties were introduced into Pt(II) complexes in order to facilitate the selective transport into cancer cells. Cholesterol esters of aminoacids and 2,3‐diaminopropionic acid were attached to the PtCl2 fragment via their NH2 groups. Steroidal amine and diamine ligands were synthesized and transformed into the corresponding dichloroplatinum(II) complexes. A steroidal carboxylic acid was prepared and coupled with the Pt(NH3)2 fragment. The antitumor activity of the compounds was tested towards the lymphatic P 388 leukemia of the CD2F1 mouse and towards the human mammary carcinoma cell line MDA‐MB 231. The Pt(II) complexes gave a maximum growth inhibition of 54%.
A Theoretical (AM1) and Experimental Dipole Moment Study of 5(4H)‐Oxazolones
Authors: Cativiela C. , Díaz De Villegas M. D. , Fayet J. P. , García J. I. , Mayoral J. A. , Vertut M. C.
Published: September 2010

Experimental and calculated (AM1) dipole moments have been determined for a series of Z and E‐isomers of 4‐phenylmethylene‐5(4H)‐oxazolones (1) and 4(α‐phenylethylidene)‐5(4H)‐oxazolones (2) in order to study the conformation in solution of the phenyl group in position 4. The comparison between experimental and calculated values for the Z‐isomers indicates a planar conformation of the phenyl group. In the case of E‐isomers the agreement is good for IE, which is probably planar, but not so good for 2E, although the perpendicular form shows better agreement. These results have been confirmed by 1H‐NMR.
The Molecular Structure of the Steroidal Isoxazolidine Products Derived from (Z)‐3β,17β‐Diacetoxy‐19‐NOR‐5,10‐Secoandrost‐1(10)‐En‐5‐One
Authors: Tinant B. , Declercq J. P. , Lorenc L.J. , Rajkovic M. , Milovanovic A. , Mihailovic M. Lj.
Published: September 2010

X‐Ray analysis of the steroidal isoxazolidine derivatives 2 and 3b, which are formed (the latter as the corresponding diacetate 3a) in the reaction of (Z)‐3β,17β‐diacetoxy‐19‐nor‐5,10‐secoandrost‐1(10)‐en‐5‐one (1) with N‐methylhydroxylamine, has revealed that both compounds (and therefore also 3a) have the same cis‐1β, 5β‐epoxyimino bridge structure. The conformations of the two molecular skeletons are compared.
Lifetime of the Triplet State of Methylene Blue in the Presence of Salicylic Acid
Authors: Sedlák Petr , Vidóczy Tamás , Luňák Stanislav
Published: September 2010

A break the lifetime of MBH2+ (T1) vs. salicylic acid concentration plot occurs at around 6 × 10 E(‐5) M (corresponding to pH of the solution 4.3). This pH is close to pK1 of leucomethylene blue. The quantum yields of 2,3‐dihydroxybenzoic acid increase with increasing salicylic acid concentration over the whole range investigated (9 × 10 E(‐6) ‐ 3 × 10 E(‐4)M); the growth of the quantum yields becomes more pronounced for pH < 4.35, too.
Catalytic Spectrophotometric Determination of Ruthenium by Flow Injection Analysis Using Amido Black 10B and KIO4
Authors: Xingguo Chen , Zhide Hu , Hongwen Zheng
Published: September 2010

A new method has been developed for the determination of trace ruthenium by flow injection analysis. The proposed method is rapid, simple and sensitive. The method has a limit of detection for ruthenium of 0.050 μg/mL and permits 60 determinations per hour. The method has been applied to determine ruthenium in refined ore with satisfactory results.
Determination Bioelectrocatalytique Du Glucose En Presence D'Autres Glucides. Specificite Du Dosage
Authors: Stoytcheva Margarita
Published: September 2010

The specificity of the bioelectrocatalytical glucose determination with a chronoamperometric detection was tested. It was demonstrated that the high specificity of the enzymatic methods was conserved and the glucose analysis can be accomplished in presence of galactose, maltose, fructose and saccharose.
Bridge Flipping Data from Dynamic 1H‐NMR Spectra of 2,6‐Dimethyl‐[9](3,5)‐Pyridophane and its Pyrylium and N‐Methylpyridinium Analogs
Authors: Balaban Alexandru T. , Balaban Teodor‐Silviu , Nitta Makoto , Kanomata Nobuhiro
Published: September 2010

Dynamic 1H‐NMR spectra between room temperature and −90 °C for the title compounds indicate that the flipping of the nonamethylene bridge is slowed down on cooling (ΔGc‡ = 9.8 kcal/mol for the 2/8 methylene groups in the pyridinophane with coalescence temperature Tc = −58 °C) but the pseudorotation persists even at −90 °C. The bridge flipping is somewhat easier in the N‐methylpyridinium (ΔGc‡ = 9.7 kcal/mol, Tc = −63 °C) and in the pyrylophanium perchlorates (ΔGc‡ = 8.9 kcal/mol, Tc = −78 °C).
Synthesis of Pyridine Containing Macrocyclic Schiff Bases and Their Corresponding Polyamines
Authors: Dhont K. I. , Lippens W. , Herman G. , Goeminne A. M.
Published: September 2010

Three macrocyclic Schiff bases have been synthesized by [2+2] condensation of 2,6‐pyridinedicarbaldehyde with 1,4,7‐triazaheptane, 1,5,9‐triazanonane and 1,5‐diazapentane. Another Schiff base was synthesized by [1+1] condensation of the dicarbaldehyde with 1,5,9‐triazanonane. They were reduced with NaBH4 of the corresponding saturated octaaza, hexaaza and tetraaza polyamines.
EPR, XPS and Spectra Studies of Some 3D Complexes with Salicylidene‐Benzol Hydrazide
Authors: Bo Wang , Dianzhong Feng
Published: September 2010

Studies of transition metal complexes with salicylidene‐aroyl hydrazide Schiff base have been subject of many investigations (1,2). In this communication we present the synthesis, EPR, XPS, electronic and vibrational spectra of Co(II), Ni(II), Cu(II), Mn(II) and Zn(II) complexes with salicylidene‐3‐nitrobenzoyl hydrazide Schiff base (HL) ligand.
Calculation of Dipole Strengths for Magnetic Dipole Transitions in Lanthanide Spectra
Authors: Görller‐Walrand C. , Fluyt L. , Verhoeven P. , Berghmans E. , Vandenberghe G. M.
Published: September 2010

The quantitative treatment of intensities of lanthanide spectra has been the subject of several papers [1],[2],[3],[4],[5]. However due to the kind of samples used or to the type of polarisation of the light, some subtle differences in the expressions relating calculated and experimental values appear to be very misleading for the interpretation of the results. It is thought that subsequent papers could gain in clarification by using Table 1., derived in this paper.
Étude du Mécanisme de La Réaction D'Hydrocondensation D'Oxydes de Carbone
Authors: Ghazi M. , Barrault J.
Published: September 2010

In this work, a reaction mechanism for oxides hydrocondensation of carbon monoxide on nickel‐molybdenum catalyst is proposed. The formation of higher alcohols may occur by a CO insertion into a growing carbon‐carbon chain whereas methanol may be formed from CO via formyl or formate species.

Hydrocarbon formation may result from superficial “CHx” species hydrogenation.
Influence de L'Acidité du Milieu Électrolytique Sur Les Caractéristiques Électrochimiques de Nouvelles Électrodes a La Bromanile
Authors: Fall M. , Dieng M. M. , Bonora Pi. , Aaron J. J.
Published: September 2010

The properties of solid electrodes constituted of a mixture of bromanil and acetylen black have been investigated. The influence of the acidity of the electrolytic medium (sulfuric acid) on the electrochemical characteristics of bromanil in the solid state has been studied by galvanostatic and chronopotentiostatic methods.
Synthesis and HPLC Separation of 6‐Fluoro‐L‐Dopa Metabolites
Authors: Luxen A. , Monclus M. , Hendrickx P.‐Y. , Masson C. , Melega W. P.
Published: September 2010

The synthesis of 6‐fluoro‐L‐dopa metabolites (3‐O‐methyl‐6‐fluorodopa (1b), 6‐fluorodopamine (2a), 3‐O‐methyl‐6‐fluorodopamine (2b), 3,4‐dihydroxy‐6‐fluorophenylacetic acid (3a) and 6‐fluorohomovanillic acid (3b)) is described. A HPLC method for their separation is also presented.
Determination of Some 1,4‐Benzodiazepines by Oxidative Coupling of their Acid‐Induced Degradation Products
Authors: El‐Yazbi Fawzy A. , Galal Shereen M. , Blaih Salah M.
Published: September 2010

The oxidative coupling reaction of 3‐methylbenzothiazolone hydrazone with aromatic amines was applied to the determination of five 1,4‐benzodiazepine derivatives. The drugs were first hydrolyzed in acid medium and the liberated benzophenone derivatives were reacted with the chromogenic reagent in the presence of cerric ammonium sulphate to give a pink color. A linear correlation was found between the absorbance at λmax and concentration. The method was applied to the determination of these drugs in bulk powder and in pharmaceutical preparations. The procedure was extended to develop a stability‐indicating method for these drugs.
Computer‐Assisted Investigation of Possible Rearrangements of (Ch)N (N = 4,6,8,10) Annulenes
Authors: Atovmyan Igor L. , Shcherbukhin Vladimir V. , Zefirov Nikolai S.
Published: September 2010

Application of the computer program for the rationalization and prediction of possible rearrangements in annulenes with the common formula (CH)n (n = 4‐10) is considered. Processes of [2+2]‐, [2+2+2]‐, [4+2]‐cycloaddition and [4]‐, [6]‐ electrocyclic reactions in the families of annulenes are discussed. A list of all possible reactions proceeding as [1,3]‐, [1,5]‐, [3,3]‐sigmatropic shifts in cyclopolyene structures is presented. The whole set of known annulene reactions is reproduced. A wide set of prospective rearrangements is predicted, including several interesting examples of the degenerate Cope rearrangement.
Nouveaux Décontaminants. Destruction Chimique du Paraoxon Et du Parathion au Moyen de Composés a Chlore Positif
Authors: Hedayatullah Mir , Lion Claude , Tourki Amel
Published: September 2010

The use of compounds possessing positive chlorine and precursors of hypochlorite anions, with different micellar systems, permits the very rapid and complete destruction of paraoxon and parathion taken as models of insecticides or potent chemical warfare agents. Their optimized half‐lives are respectively 49 and 142 seconds.
Determination of Mo(VI) with 2‐Indolehydroxamic Acid by Differential Pulse Polarography and Cathodic Stripping Voltammetry
Authors: Valiente P. , Jimenez M. , Sanchez A. , Lopez‐Arza V. , Rodriguez J.
Published: September 2010

In this paper, the polarographic reduction of 2‐IHA and its Mo(VI)‐2‐IHA complex by differential pulse polarographic and by cathodic stripping voltammetry are shown. Very low detection limits have been achieved using cathodic stripping voltammetry to determine this method.
Influence de La Nature du Solvant Sur La Dépendance du Volume Molaire Et de La Conductivité des Solutions D'Électrolytes Vis‐A‐Vis De Leur Concentration
Authors: Claes P. , Mestdagh C. , Glibert J.
Published: September 2010

The systems investigated in this work are composed of the ternary eutectic mixture NH4NO3‐NH4Cl‐LiNO3 (66.7:9.5:25.8 mol. %) on the one hand and of ethylene‐glycol, formamide, dimethylformamide or dimethylsulfoxide on the other hand. The influence of the composition of these mixtures on their molar volume and on the electrical conductivity has been evidenced. At high electrolyte concentration, the composition dependence of the molar volume is explained by the exclusive localisation of the molecular compound in the solvation shell of the ions. The comparison of the conductivity isotherms points out the influence exercised by the dimensions and by the shape of the molecules of the non‐electrolyte on the ionic mobilities.
Medium Effect on the Base‐Catalysed Hydrolysis of Substituted Triphenylsilanes in Acetonitrile
Authors: Tondeur J.‐J. , Vandendunghen G. , Borghese A.
Published: September 2010

The hydrolysis of some p‐substituted triphenylsilanes in the presence of tetrabutyl‐ammonium hydroxide has been investigated in various water‐acetonitrile media with the aim of comparing the results with those already published for triphenylsilane. It appears that the initial rate is first order with respect to both silane and base whereas the order during the time is not constant for some silanes, depending on the water composition. The second order rate constant varies in agreement with the Hammett substituent constant σp. From the calculations of the transfer Gibbs functions for the activated state and for OH− from a reference medium (water mole fraction = 0.225), it is concluded that the solvent effect is not fundamentally altered by the p‐substituents and that the medium influence on the rate can be essentially attributed to solvation modifications around OH−.
Molecular Structure Analysis of Moclobemide, a Monoamine Oxidase Inhibitor
Authors: Wouters J. , Moureau F. , Norberg B. , Evrard G. , Durant F.
Published: September 2010

The crystal structure of Moclobemide,p‐chloro‐N‐(2 morpholinoethyl) benzamide is reported and compared with that of Moclobemide hydrochloride monohydrate. There is free rotation of the phenyl ring and the amidic function of the benzamide moeity as confirmed by a conformation analysis performed with the PCILO “Perturbative Conformation Interaction using Localized Orbitals” method. C13H17N2O2Cl, Mw=268.4, primitif, P‐1, a=11.569(3), b=13.814(4)Å, C10.004(2), α=98.27(2), β=113.87(2), γ=104.13(2)°, V=1363.7Å3, Z=2, DC1.31 g·cm−3, Mo Kα, λ=0.71060Å, μ=2.32 cm−1, F(000)=568.0, T=293 K, final Rw=0.080 for 2995 observed reflections (I≥2 σ(I)).
3′‐5′ Cyclic Oligothymidylic Acids: Conformation and Complexation of Intercalating Agents
Authors: Hamoir G. , Sonveaux E.
Published: September 2010

The cyclic oligonucleotides c‐(TpTp) 4a, c‐(TpTpTp) 4b and c‐[(3‐Me)Tp(3‐Me)Tp] 4c were synthesized. Their conformations were studied by NMR (500 MHz) and CD spectroscopies. The association constants of proflavine and ethidium bromide with 4a and 4b were determined.
Selective Hydrogenation of Styrene on Pd‐Ho/γAl2O3 and Pd/γAl2O3 Catalysts
Authors: Pârvulescu V. I. , Pârvulescu V. , Frunza L. , Grecu N. , Enache C. , Angelescu Em.
Published: September 2010

Pd‐Ho/γAl2O3 catalysts exhibit higher activity for styrene hydrogenation than Pd/γAl2O3 ones. The addition of holmium to Pd catalysts changes the place of the palladium impregnation front depending on the state of the supported palladium. As a consequence of the interaction between holmium and Pd/γAl2O3 support, oxidized forms as holmium aluminate were formed. These forms are catalytically inactive but represent adsorption centers for styrene. On holmium containing catalysts, hydrogenation takes place between the styrene adsorbed on basic centers and the hydrogen spilled over from palladium particles.
Le Mécanisme D'Extinction des Feux D'Hydrocarbures Par Les Halons
Authors: Antonik S.
Published: September 2010

The most recent theories on the inhibition of hydrocarbon flames by halogen containing compounds are critically reviewed: Mill's ionic theory, Creitz's theory and the theory of inhibition by HBr. New results from simultaneous experiments on halons‐H2‐air and halons‐air mixtures have given a new insight into the mechanism of extinction of hydrocarbon fires by these compounds. More precisely, the new mechanism takes into account some valuables processes which are present separately in the three mentioned hypothesis.
Simultaneous Determination of Folpet and Fenamiphos in Water and Pesticide Formulations by Derivative Spectrophotometry
Authors: Ocaña D. Cervantes , Garcia M. D. Gil , Galera M. Martinez , Vidal J. L. Martinez
Published: September 2010

A new method is described to analyse the binary mixture of folpet and fenamiphos, using the first derivative spectrophotometry obtained by mathematical treatment of the data. Calibration graphs were linear between 1.0 to 15.0 μg·mL−1 of folpet and between 1.2 to 27.9 μg·mL−1 of fenamiphos. The method has been applied for determining both pesticides in commercial formulations and groundwater at ng.mL−1 levels after a preconcentration step with C18.
Structure of Ternary Solvent Mixtures. Part I. Water ‐ 1,4‐Dioxane ‐ Organic Solvent Mixtures
Authors: Mazurkiewicz Józef , Tomasik Piotr
Published: September 2010

Using rotary viscometry rheology was studied for ternary solvent mixtures composed of water, 1,4‐dioxane and one of such organic solvents as acetic acid, acetone, acetonitrile, N,N‐dimethylformamide, dimethyl sulfoxide, formamide, methanol, 1‐propanol or pyridine. The structure of solvates was determined and the intermolecular interactions involved are discussed.
Crystal Structures of CH2 = CHCH2OC(O)CH2CH2SnCl3.OPPh3 and BuOC(O)CH(CH3)CH2SnCl3.OPPh3
Authors: Gielen Marcel , Pan Huade , Tiekink Edward R. T.
Published: September 2010

The crystal structures of the title compounds, CH2CHCH2OC(O)CH2CH2SnCl3.OPPh3 1 and BuOC(O)CH(CH3)CH2SnCl3.OPPh3 2, have been determined. The Sn atom in each structure exists in a distorted octahedral geometry defined by three CI atoms, the C and O atoms of a chelating alkoxycarbonylalkyl group and an O atom derived from the strongly attached OPPh3 ligand.
Cyclodimérisation Asymétrique du Penta‐2,4‐Dienoate de Méthyle Activée Par Un Complexe du Nickel
Authors: Masotti H. , Peiffer G. , Siv Ch. , Valls R. , Faure R.
Published: September 2010

The reaction of asymmetric cyclodimerization of penta‐2,4‐dienoic acid methyl ester was investigated by the catalytic system: Ni(acac)2 / Et2AlOEt / L‐Threophos. A 92% convertion was obtained. The main product is the (Z)‐3‐carbomethoxy 4‐(2‐carbomethoxy vinyl) cyclohexen and the enantiomeric excess determinated by chiral HPLC and NMR methods is about 25%.