bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial Oxidation of Geranylacetone and Geranyloxycoumarin, Aurapten
Authors: Müller A. , Abraham W. R. , Kieslich K.
Published: September 2010

Geranylacetone and geranyloxycoumarin (aurapten) were investigated with 14 selected microorganisms for ω‐hydroxylation and epoxydation of the subterminal double bond. Trichoderma koningii and Verticillium theobromae are in principal useable for both reactions of geranyacetone. Although the yields of these preferably intended reactions were low, while ω‐1‐, ω‐3‐, ω‐4‐hydroxylations partially combined with reductive side reactions take place, the results gave an insight in the different pathways of oxidations dependent on the microorganism used. In contrast aurapten is transformed in relatively high yield to the E‐ or/and Z‐configurated ω‐alcohols (auraptenols) and to the aurapten‐6,7‐epoxide. The exclusively useable microorganisms for the oxidation of aurapten selected from the 237 strains tested were Nocardia alba and Bacillus cereus, which both formed enantioselectively the naturally configurated epoxyaurapten R‐(+)‐[6′,7′‐epoxy‐3′,7′‐dimethyl‐2′ octenyl]‐7‐oxycoumarin in yields of 10.5% respectively 21% of excellent optical purity of 99%ee.
Total Synthesis of Periplanone‐B Via Intramolecular Diels‐Alder Reaction with Furan‐Diene and Allene‐Dienophile
Authors: Geyter Tom De , Cauwberghs Serge , De Clercq Pierre J.
Published: September 2010

A synthetic route towards (±)‐periplanone‐B is described based on (i) an intramolecular Diels‐Alder reaction involving a furan‐diene and an allene‐dienophile, (ii) selective (C‐O)‐cleavage in the resulting adduct by lithium di‐tert‐butylbiphenyl radical anion; (iii) a Grob fragmentation leading to the ten‐membered ring, as key‐steps.
Dichloro(2,2‐Dimethylcyclopropyl)Methyl Phenyl Sulfone ‐ a Radical Probe for Detecting Single Electron Transfer Processes
Authors: Makosza Mieczyslaw , Kwast Andrzej
Published: September 2010

The title compound was synthesized and was shown to be a fast radical probe for studying single electron transfer processes in reactions of carbanions with polyhaloalkanes. It has a universal character ‐ being originally an electron acceptor, upon dehelogenation forms carbanion which is an electron ‐ donor radical probe.
The Reaction of Perfluorobutanesulfonyl Fluoride with Alcohols in the Presence of 4‐Dialkylaminopyridines
Authors: Bennua‐Skalmowski Bärbel , Krolikiewicz Konrad , Vorbrüggen Helmut
Published: September 2010

Primary hydroxy groups as in neopentyl alcohol 7 or neopentylglycol 18 react readily with perfluorobutanesulfonyl fluoride 1 in the presence of 2 equiv. of the nucleophilic 4‐dialkylaminopyridines 4 to afford high yields of the corresponding N‐alkyl‐4‐dialkylaminopyridinium perfluorobutanesulfonates (nonaflates). Secondary hydroxy groups give rise to a mixture of the corresponding olefins and monofluorides as well as of the corresponding N‐alkyl‐4‐dialkylaminopyridinium nonaflates.
Synthesis of Glycosidase‐Inhibiting Iminopolyols Via Isoxazolines1,2
Authors: Jäger Volker , Müller Rudolf , Leibold Thomas , Hein Matthias , Schwarz Marietta , Fengler Marion , Jaroskova Libuse , Pätzel Michael , Leroy Pierre‐Yves
Published: September 2010

The 1,3‐dipolar cycloaddition of allyl halides with chiral nitrile oxides, derived from glyceraldehyde derivatives, affords ca. 1:1‐mixtures of C5‐epimeric isoxazolines. The diastereomers can be separated on a preparative scale by MPLC; the configurations at C5 are established by chemical correlation/X‐ray analysis initially, and then routinely, based on consistent, large differences of respective specific rotations. – An unexpected finding, which turned out to be the key to efficient transformation of 5‐halomethyl‐isoxazolines into hydroxy‐pyrrolidines, is that highly stereoselective catalytic hydrogenations are feasible with proper combination of both 3‐ and 5‐side chain structures and the catalyst system. – This (C3 + Cn)‐approach is extended to include dihydroxy‐pyrrolidines, i. e. 1,4‐iminopolyols, and further 1,5‐iminopolyols and bicyclic 1,5,8‐iminopolyols. The substrates for the latter hydrogenation/cyclization are derived from optically active furoisoxazolines. – Some of the new iminopolyols show strong inhibition of glucosidases.
Phosphorus Substituted “CN2 ” Groups: Building Blocks in Heterocyclic Chemistry
Authors: Baceiredo Antoine , Réau Régis , Bertrand Guy
Published: September 2010

The synthesis and reactivity of diazomethylenephosphoranes 2, bis(phosphanyl)carbodiimide 5, and N‐phosphanyl nitrilimine 10 are presented. The synthesis of transient N‐phosphanyl isodiazirine 19 and its rearrangement into 1,3,2λ5‐diazaphosphete 20 are discussed.
Design and Synthetic Applications of New Heterometallacycles
Authors: Echavarren Antonio M. , Cárdenas Diego J. , Castaño Ana M. , Cuerva Juan M. , Mateo Cristina
Published: September 2010

The reaction of cyclic anhydrides with Ni(0) complexes lead to the formation of nickelacycles by oxidative addition followed by decarbonylation. The preparation of chiral nickelacycles from anhydrides derived from amino acids and their reactivity is described. The formation of new heteropalladacycles by C‐H activation or transmetallation reactions and their reactivity will be also discussed.
Palladium‐Catalyzed Aerobic Oxidation of Allylic Amines via Heterocyclic Intermediates
Authors: Hiemstra Henk , van Benthem Rolf A. T. M.
Published: September 2010

The efficient transformation of allylic amines into 2‐amino‐3‐alken‐1‐ols and 1,2‐diamino‐3‐alkenes is described. The key step is the functionalization of the π‐bond of the starting material via palladium(II)‐mediated attack by an oxygen or nitrogen nucleophile, followed by palladium hydride elimination. When this reaction is carried out in DMSO as the solvent, molecular oxygen serves as a clean and efficient oxidant (without the need of a co‐oxidant), thus making the process catalytic in palladium. By tethering the nucleophile to the nitrogen atom of the starting allylic amine, the intramolecular character of the key reaction ensures excellent regio‐ and stereoselectivity in several cases. The tether is readily removed by using an electrochemical oxidation and hydrolysis.
Highly Stereocontrolled Formal Total Synthesis of Hemibrevetoxin B
Authors: Yamamoto Yoshinori , Kadota Isao
Published: September 2010

Stereocontrolled synthesis of hemibrevetoxin B framework, 7,7,6,6‐tetracyclic ether skeleton, has been accomplished via the intramolecular allylic tin‐aldehyde (and ketone) condensation.
AIPO4 AS CATALYST IN ORGANIC REACTIONS. V. INFLUENCE OF THE CHEMICAL AND TEXTURAL PROPERTIES OF SOLID CATALYST IN THE ESTERIFICATION PROCESS
Authors: Fernández‐Sánchez C. , Gandasegui M. T. , Marinas J. M. , Sinisterra J. V.
Published: September 2010

The influence of the chemical and textural properties of several aluminium orthophosphates catalysts in the esterification of acetic acid with n‐amyl alcohol is studied. The surface area but not the number of acid site of the catalyst is the determinant property in the catalytic activity. The influence in the yield of the water present in the medium is analyzed.
LINEAR AND ANGULAR ANALOGUES OF 5‐METHOXYFUROCOUMARIN
Authors: Antonello Cipriano , Zagotto Giuseppe , Miranda RocÍO , Uriarte Eugenio
Published: September 2010

Formation of the furan ring of 5‐methoxyfurocoumarins by cyclization of the corresponding keto‐ether gave angular and linear isomers in ratios varying between 3:1 and 3:2 in favour of the angular isomer. Starting 7‐hydroxy‐5‐methoxy‐4‐methylcoumarin (5) and its 5‐hydroxy‐7‐methoxy isomer (6) were obtained in approximately 1:1 ratio by Pechman reaction of 5‐methoxyresorcinol (4) and ethyl acetoacetate. All products were isolated by flash chromatography and characterized by NOE spectroscopy.
SYNTHESIS, CHARACTERIZATION AND ELECTRIC PROPERTIES OF TERNARY LANTHANIDE(III) COMPLEXES WITH M‐HYDROXYBENZOATE AND THE BIDENTATE LIGAND (BIPY OR PHEN)
Authors: Zhao Xiueyuan , Wang Liufang , Wang Shuangxi , Wu Jigui , He Fengying , Xu Jiwu
Published: September 2010

The ternary lanthanide (III) complexes with m — hydroxybenzoate and the bidentate ligand (the ligand = bipy. phen) having the formulas Ln(bipy)L3. nH2O and Ln(phen) L3(where L = m‐hydroxybenzoate, Ln = La, Gd, Dy, Y) have been prepared and characterized by elemental analyses, IR and electronic spectra, molar conductance and thermal analyses. The electrically conductive properties for these complexes have also been examined. It has been found that the bipy complexes have semiconductor properties, whereas the phen complexes don't.
FACILE SYNTHESIS OF 2‐SUBSTITUTE BENZOTHIAZOLES VIA KETENES
Authors: Abayeh O. J. , Olagbemiro T. O. , Agho M. O. , Amupitan J. O.
Published: September 2010

The generation of phenyl‐, diphenyl‐, phenoxy‐, and chloroketenes, by the dehydrochlorination of the corresponding acid chlorides with triethylamine, in the presence of 2‐aminothiophenol 1 gave 2‐substituted benzothiazoles 3 in good yields.
ORTHOAMIDES, XLVIII: REACTIONS OF AN AZAVINYLOGUE AMIALESTER [2‐AZA‐1,3‐BIS(DIMETHYLAMINO)‐3‐METHOXY‐1‐PROPEN] WITH CH2‐ACIDIC COMPOUNDS
Authors: Kantlehner Willi , Hauber Michael
Published: September 2010

Condensation reactions of azavinylogue orthoamides 5a and 6a with CH2‐acidic compounds are described. Reaction products are formylated ‐ or azavinylogue formylated compounds 8 and 9 resp. The condensation reactions of 5a can be enhanced by addition of trimethyl borate. Under these conditions the formylations reaction‐leading to compounds of type 8 ‐ is preferred.
SYNTHETIC MODIFICATIONS OF ANTISENSE OLIGONUCLEOTIDES: NOVEL BACKBONE REPLACEMENTS WITH IMPROVED PROPERTIES
Authors: Mesmaeker Alain De , Waldner Adrian , Fritsch ValÉRie , Lebreton Jacques , Wolf Romain M.
Published: September 2010

Eleven different types of backbone replacements have been investigated. The thermodynamic stability of the duplexes formed between these modified oligonucleotides and their RNA complements are summarized. Among these backbone replacements, we identified two amide derivatives which display improved properties for their application to the antisense strategy. A summary of our molecular modeling study on some of these modifications is also presented.
CYCLOADDITION DIPOLAIRE‐1,3 DES N‐ARYL‐C‐ETHOXYCARBONYLNITRILIMINES SUR LA 1‐METHYL‐5,7‐DIPHENYL‐1,4‐DIAZEPINE ET SUR LA 2‐METHYL‐4‐PHENYL‐1,5‐BENZODIAZEPINE
Authors: Baouid A. , Benharref A. , Hasnaoui A. , Lavergne J. P.
Published: September 2010

The reaction of N‐aryl‐C‐ethoxycarbonyl nitrilimines with the title compounds leads to [1,2,4] triazolo [1,4] diazepine, [1,2,4] triazolo [1,5] benzodiazepine and bis [1,2,4] triazolo [1,5] benzodiazepine. The 1,3‐dipolar cycloaddition is completely peri and regioselective.
ADDITION DE 2‐ALCOXYCARBONYL AZIRIDINES YLURES D'AZOMETHINE POTENTIELS A QUELQUES VINYLISOCYANATES
Authors: Mamoun O. , Benhaoua H.
Published: September 2010

The addition of azomethine ylides generated from the thermal ring opening of the corresponding 2‐alcoxycarbonylaziridines on various vinylisocyanates occured exclusively on the CN double bond. Only one orientation of the addition was observed in accordance with previous work in this area. The structure of the epimeric imidazolidones obtained was established by spectroscopic methods (RMN1H, 13C and mass spectrometry).
OLD AND NEW APPROXIMATE FORMULAE FOR ELEMENTARY PH CALCULATIONS, AND THEIR LIMITS OF APPLICABILITY
Authors: Cardinali Mario E. , Giomini Claudio , Marrosu Giancarlo
Published: September 2010

The paper discusses the limits of applicability of the most common approximate formulae employed for calculating the [H3O+] value of aqueous solutions containing a weak electrolyte whose acid‐base behaviour is completely described by a single ionization process. These limits are so fixed as to avoid that absurd results are obtained. In addition, a new simple formula is proposed, that overcomes some drawbacks of the traditional formulae, and an unknown, singular feature of a well‐known formula is pointed out.
UNSUPPORTED NiMo CATALYSTS. INFLUENCE OF THE SULFINDING TEMPERATURE AND EVOLUTION OF THE UNSUPPORTED NiMoS PHASE DURING REACTION
Authors: Karroua M. , Matralis H. , Grange P. , Delmon B.
Published: September 2010

A series of unsupported NiMo catalysts, containing 30% Ni atoms, were prepared by the homogeneous sulfide precipitation method (HSP) and sulfided at different temperatures in the range 673‐1073 K. XPS, XRD, microelectrophoresis and BET surface area measurements were used to characterize the samples. The catalytic activity of the various catalysts for the hydrodesulfurization of thiophene and the hydrogenation of cyclohexene in a mixture containing both compounds was measured in mild conditions (573 K, 3 MPa). Both the evolution of the “NiMoS phase” during catalytic reaction and the influence of the sulfidation temperature on the properties of the unsupported NiMo catalysts were investigated.

The sample sulfided at 673 K gave all the characteristic signals of the “NiMoS phase”. As the sulfidation temperature increases, larger amounts of nickel segregate from “NiMoS phase” to form nickel sulfide. The “NiMoS phase” was found unstable under reaction conditions. The maximum catalytic activity for both HDS and HYD reactions was obtained when both “NiMoS phase” and bulk Ni3S2were present in the catalyst. It thus appears as a precursor of a very active mixture of phases rather than of the stable catalyst itself. These results are discussed in relation to some models attempting to explain the synergy in the NiMo catalysts. They are compatible with the remote control mechanism.
SYNTHESE D'AMINO ACIDES PYRAZOLIQUES
Authors: El Mahdi O. , Lavergne J.‐P. , Viallefont P. H. , Akssira M.
Published: September 2010

In the field of our synthesis of heterocyclic amino acids, we describe here the preparation of two regioisomeric pyrazolic amino acids.
PREPARATION DE PYRROLIDINES N‐METHYLEES A PARTIR DE PYRROL‐1‐INES
Authors: Perrocheau J. , Danion D. , Carrié R.
Published: September 2010

Pyrrol‐1‐ines obtained by 1,3‐dipolar cycloaddition of nitriles ylides to gem‐disubstituted by withdrawing groups olefins are converted to 1‐pyrrolinium salts by methylfluorosulfonate. Nucleophilic addition to these iminium salts affords 1 ‐pyrrolidines in good yields. Attempts to synthesize aziridines by thermolysis or flash thermolysis of these pyrrolidines through cycloreversion was unsuccessful. However the fragmentation under electronic impact of the pyrrolidines obtained from imidoyl chloride 5A and 5B allowed us to establish the 5 position of the paranitrophenyl group in the pyrrol‐1‐ine cycloadducts.
A CONVENIENT ACCES TO 1,7‐DIFUNCTIONAL NAPHTHALENES: THE SYNTHESIS OF THE 1,7‐DICARBALDEHYDE 7‐MONODIMETHYLACETAL
Authors: Jouanno Chantal , Floc'H Yves Le , Grée René
Published: September 2010

An easily accessible route to the 1,7‐dicarbaldehyde 7‐monodimethylacetal 7 is described. It proceeds in a six step sequence from the known 7‐methyl‐l‐tetralone.
REACTION DES METHYLENE γ‐BUTYROLACTONES AVEC LES ARYLNITRILOXYDES. EVOLUTION INATTENDUE DU BISADDUIT ISSU DE LA 5‐METHYLENE(5H)FURAN‐2‐ONE
Authors: Fihi Rachid , Ciamala Kabula , Vebrel Joël , Rodier Noël
Published: September 2010

In explorations of synthesis and chemistry of spiroheterocycles, we found that reaction of aromatic nitrile oxydes with methylene γ‐butyrolactones (at room temperature) produced spiroheterocycles 4, 5 and 6. When cycloadditions were carried out in refluxing toluene, the methylene(5H)furan‐2‐one 3 gives a totally unexpected product 8.
STUDIES ON MACROCYCLIC DITERPENOIDS (XV) ‐ TOTAL SYNTHESIS OF (R)‐(‐)‐CEMRENE‐A
Authors: Yue Xiangjun , Li Yulin
Published: September 2010

The total synthesis of (R)‐(‐)‐cembrene‐A was described in ∼29% overall yield from E‐geranyl acetone and (R)‐(+)‐limonene through ten steps by using the modified Wittig reaction and titanium‐induced intramolecular carbonyl coupling as key steps.
FIRST TOTAL SYNTHESIS OF (‐)‐DEHYDROCARISSONE
Authors: Liu Lijun , Xiong Zhaoming , Nan Fajun , Li Tongshuang , Li Yulin
Published: September 2010

The first synthesis of (‐)‐ dehydrocarissone (1) has been described, employing the dehydrogenation with DDQ as the key step.
SIMPLE AMPHOLYTIC ELECTROLYTES A SHORTCUT TO AN ACCURATE pH CALCULATION
Authors: Giominl Claudio , Marrosu Giancarlo , Cardinali Mario E.
Published: September 2010

The interval bisection method is employed to find the pH of the aqueous solutions of those electrolytes which are characterized by only one acid, and only one basic, ionization process.
CRYSTAL STUDIES OF MUSK COMPOUNDS. XIV. A REDETERMINATION OF THE MOLECULAR STRUCTURES OF THREE NITROBENZENE MUSKS : DISCUSSION OF THE GEOMETRY OF A TERT‐BUTYL GROUP ATTACHED TO A BENZENE RING AND EMBEDDED BY TWO NITRO GROUPS
Authors: De Ridder Dirk J. A. , Schenk Henk
Published: September 2010

The crystal structures of Musk Xylene (1, 1‐tert‐butyl‐3,5‐dimethyl‐2,4,6‐trinitrobenzene), Musk Ketone (2, 4‐acetyl‐1‐tert‐butyl‐3,5‐dimethyl‐2,6‐dinitrobenzene) and Musk Tibetene (3, 1‐tert‐butyl‐3,4,5‐trimethyl‐2,6‐dinitrobenzene) have been redetermined (1 and 3 at reduced temperature) and the accuracy is compared. Compound 2 has four molecules in the asymmetric unit but no additional crystallographic symmetry could be detected.

The tert‐butyl group in the molecules is adjacent to two nitro groups at the neighbouring sites and a systematic pattern is observed in its bond distances and angles. The influence of a tert‐butyl group on the endocyclic angles of a phenyl ring is discussed.
THERMOLYSIS OF N‐BENZYL DERIVATIVES OF 2‐AMINOPYRIDINES. A CHARGE SENSITIVITY (CS) AND MNDO STUDY OF ELECTROPHILIC SUBSTITUTION OF 2‐AMINOPYRIDINES
Authors: Kowalski Piotr
Published: September 2010

The thermolysis reaction of N‐mono (1, 2) and N‐disubstituted (3, 4) benzyl derivatives of 2‐aminopyridines were carried out at 250°C in order to verify the scheme of the reaction of 2‐aminopyridines with electrophiles. N‐Annular benzyl substituent in 1 and 3 rearrange into N‐exocyclic (2 and 4, respectively) both in mono and disubstituted series. C‐Benzyl derivative formation (2‐benzylamino‐5‐benzylpyridine (10) hydrochloride) takes place as the result of rearrangement of N‐disubstituted benzyl derivatives, 3 and 4 hydrochlorides, only. N‐Mono benzyl derivatives, 1 and 2 hydrochlorides, did not rearrange to C‐benzyl compounds. Hard‐soft parameters of atoms‐in‐molecule (AIM) in 2‐aminopyridine systems as well as the nature of the electrophilic agent influence different reactivity of the 2‐aminopyridine systems. The N‐annular derivative formation (B) is controlled mainly by an electrostatic component (ES) i.e. interaction hard‐hard, while C‐substitution, formation of D, mainly by charge transfer (CT) component i.e. interaction soft‐soft. Increasing of effectively of N‐exocyclic (C) and C‐substituted (D) derivative formation is influenced by decreasing of the hardnesses of an electrophilic agent and hardnesses of AIM in 2‐aminopyridine system.
NICKEL(II) AND COPPER(II) COMPLEXES OF 5‐ARYL‐1‐PHENYLPENT‐1‐YNE‐3,5‐DIONES
Authors: Hassaan Aly M. A. , Marei M. G.
Published: September 2010

Ni(II) and Cu(II) complexes of 5‐aryl‐1‐phenylpent‐1‐yne‐3,5‐diones have been synthesized and characterized by elementary analysis, infrared and electronic spectra, molar conductivity and magnetic measurements. Octahedral and distorted octahedral configurations are suggested for Ni(II) and Cu(II) complexes, respectively.
VANADIUM‐TITANIUM OXIDE CATALYSTS. INFLUENCE OF THE PREPARATION METHOD ON THE o‐XYLENE SELECTIVE OXIDATION
Authors: Georgiadou I. , Slavov S. , Papadopoulou CH. , Matralis H. K. , Kordulis CH.
Published: September 2010

Vanadium oxide supported on titania catalysts prepared by the “Equilibrium Deposition followed by Filtration” method (EDF) and the conventional Wet‐impregnation method (WI) were extensively characterized by the joint use of various physicochemical techniques (BET, XRD, FT‐IR, DRS, XPS, AEM, TPR, and TPD of NH3) and were tested for the partial gas‐phase oxidation of o‐xylene. It was found that the EDF method leads to more selective monolayer catalysts. The increased selectivity has been attributed to the reduction of the surface acidity, to the enhancement of the VV/ VIV ratio and to the redox properties induced in this catalyst by the above preparation method
CONVERSATION DU GAZ DE SYNTHESE EN HYDROCARBURES LIQUIDES:INFLUENCE DU SUPPORT ET DES PROMOTEURS (La, Ce ET Mn) SUR LES CATALYSEURS AU COBALTS
Authors: Barrauit JoËL , Biwole Nazaire
Published: September 2010

The hydrocondensation of carbon monoxide into liquid hydrocarbons was studied in presence of cobalt catalysts modified with cerium, lanthanum or manganese salts and supported on carbon. After an oxidative activation of the support, the addition of cerium to cobalt increases the (C5‐C11) fraction while the addition of manganese increases the (C12‐C25) fraction.
GC/MS SEPARATION AN IDENTIFICATION OF THE C5H10 ISOMERS. APPLICATION TO THE Hg 6(3P1) PHOTOSENSITIZED REACTIONS OF cis‐2‐PENTENE, 1‐PENTENE AND trans‐1,2‐DIMEHYLCYCLOPROPANE
Authors: De Maré George R. , Termonia Marc
Published: September 2010

The analysis (separation and identification) of eleven C5H10 isomers is performed using coupled GC/MS with a 70 m glass capillary column containing a 2.5 μm thick film of PS225 as stationary phase. Cryogenic CO2 cooling improves the separations. The total analysis time is less than 12 minutes.

Some mechanistic details on the Hg 6(3P1) (hereafter denoted by Hg*) photosensitization of the title compounds are elucidated. Thus the Hg* photosensitization of cis‐2‐pentene at 20 Torr yields methylcyclobutane with a quantum yield ø = 0.1, not ethylcyclopropane as was previously thought. (Ethylcyclopropane is formed in trace quantities.) The photostationary state for the Hg* sensitization of the 2‐pentenes is confirmed to correspond to the concentration ratio [trans]/[cis] = 1.00. Trans‐1,2‐dimethylcyclopropane is a product of the Hg* photosensitization of 1‐pentene. The major products of the Hg* photosensitization of trans‐1,2‐dimethylcyclopropane at 80 Torr are 3‐methyl‐1‐butene, trans‐ and cis‐2‐pentene and cis‐1,2‐dimethylcyclopropane which are all formed with quantum yields near 0.1 and in the ratios 1.04:1.07:1.00:1.45.
THE FUNCTION OF PHOSPHORUS , NICKEL AND H2S IN THE HDN OF PIPERIDINE AND PYRIDINE OVER NiMoP/Al2O3 CATALYSTS
Authors: Jlan M. , Cerda J. L. Rico , Prins R.
Published: September 2010

The effect of phosphorus in the hydrodenitrogenation (HDN) of piperidine and pyridine over NiMo/Al2O3 catalysts was studied. In the absence of H2S no effect of P was found, but in the presence of H2S the HDN activity of NiMo/Al2O3 catalysts decreased as the P content in the catalysts increased. It is concluded that phosphorus has a negative effect on the C‐N bond cleavage in piperidine, as well as on the subsequent hydrogenation of the C5 alkene intermediates. Also the influence of Ni was found to depend on the reaction conditions. A substantial promotion effect of Ni could only be observed in the presence of H2S, both in the C‐N bond cleavage of piperidine and in the pyridine hydrogenation. The activity for the HDN of piperidine of NiMo(P)/Al2O3 catalysts increased with increasing H2S concentration up to H2S/H2 = 12.5 × 10−3 mol/mol.
PREPARATION OF UNIFORMLY DISPERSED MoP/AL2o3 CATALYSTS
Authors: Jian M. , Prins R.
Published: September 2010

Several preparative factors which determine the properties of MoP/Al2O3 catalyst have been studied. With sequential impregnation, the Mo dispersion is always worse than with co‐impregnation, while in co‐impregnation the pH of the impregnating solution should be properly adjusted according to the P content. Since both molybdate and phosphate ions interact strongly with the alumina surface, they can adsorb directly at the pore mouths and inhibit other ions to enter the pores. Especially in the case of sequential impregnation, this results in a non‐uniform distribution of Mo and P over the alumina particles. In the case of co‐impregnation, with controlled pH and enough phosphoric acid, phosphomolybdate ions are formed which interact less strongly with the alumina surface. In that case, Mo can reach the inside part of the alumina particles and attain a uniform distribution. Also the Al2O3 particle size influences the Mo dispersion. Smaller particles have more outer surface and therefore it is easier for the molybdate and phosphate ions to diffuse to the centers of the pores, so that there is less chance that bulk Mo compounds are formed.
Effect of Boron Addition on the State and Dispersion of Mo Supported on Alumina
Authors: Morishige Hidetaka , Akai Yoshio
Published: September 2010

The influence of B on the state and dispersion of Mo phases on Al2O3 have been investigated by bulk and surface characterization techniques, e.g., XRD, XPS and TPR, respectively. In the absence of B, the dispersion of Mo phases is in good agreement with the theoretical value calculated from Kerkhof‐Moulijn model, suggesting that Mo atoms disperse easily on Al2O3 surface. XPS results indicate that B addition to Al2O3 leads the Mo dispersion to decrease in comparison with the theoretical monolayer value. This result is also confirmed by XRD analysis, which shows the formation of crystalline MoO3 particles with B addition. TPR profiles for Mo/Al2O3 consists of two reduction peaks, a low temperature peak (400°C ± 450°C) and a high temperature one (770°C ± 810°C), respectively. The peak Intensity of the higher temperature decreases rapidly with B addition, whereas that of lower temperature increases with increasing B contents. Consequently, these results suggest that B addition weakens the interaction between Mo species and the Al2O3 surface.
Effect of H2S and NH3 on Aromatics Hydrogenation Over Sulfided Pt and NiMo Based Hydrotreating Catalysts
Authors: Mignard S. , Marchal N. , Kasztelan S.
Published: September 2010

The influence of H2S or NH3 partial pressure on the rate of toluene hydrogenation over sulfided NiMo and Pt catalysts has been investigated. H2S is an inhibitor for both catalysts and its negative effect is totally reversible. NH3 is also a contaminant, however, its negative effect is only partially reversible. At very low H2S and NH3 partial pressure and in the same operating conditions, the Pt catalyst is always more active per gram of metal than the NiMo catalyst. The NiMo sulfide catalyst is more sensitive to NH3 than to H2S whereas the Pt catalyst is more sensitive to H2S than to NH3.
Organometallic Complexes as Models for the Adsorption of Thiophenes on Hydrodesulfurization (HDS) Catalysts
Authors: Angelici Robert J.
Published: September 2010

In this review are discussed the known modes of thiophene coordination η1(S), η2, η4 and η5) in organometallic complexes. Their structures, bonding and stabilities are related to the adsorption of thiophene on heterogeneous hydrodesulfurization (HDS) catalysts. Modes of benzo[b]thiophene and dibenzothiophene coordination in organometallic complexes are briefly summarized.
The Bond Energy Model for Hydrotreating Reactions: Theoretical and Experimental Aspects
Authors: Topsøe H. , Clausen B. S. , Topsøe N.‐Y. , Nørskov J. K. , Ovesen C. V. , Jacobsen C. J. H.
Published: September 2010

Recently, we have shown that the periodic variations in the HDS activities of different transition metal sulfides can be explained by a Bond Energy Model (BEM) based on theoretically calculated metal sulfur bond energies. The model differs from many previous explanations for the observed Balandin‐type volcano curves. Specifically, the BEM model suggests that under most conditions, the variations in HDS activities are dominated by differences in the concentration of coordinatively unsaturated sites (CUS). The model has also been used to estimate the metal sulfur‐bond strength of Co‐Mo‐S and NL‐Mo‐S and the promotion is explained in terms of the estimated bond energies for the different types of surface structures. EXAFS and TPR‐S results are seen to provide experimental evidence for the BEM model. Besides coordinatively unsaturated sites, surface SH groups are also present and new evidence is presented based on 1H MAS NMR measurements. SH groups may also play an important catalytic role in the supply of hydrogen and for acid catalyzed reactions. The relative importance of the SH groups and the CUS sites appears to depend critically on the metal‐sulfur bond energy. Furthermore, the BEM model is shown to provide a useful starting point for understanding various reactivity trends observed under different reaction conditions.
Interaction of Thiophene with a Molybdenum Disulfide Catalyst: An Inelastic Neutron Scattering Study
Authors: Mitchell P. C. H. , Green D. A. , Grimblot J. , Payen E. , Tomkinson J.
Published: September 2010

The inelastic neutron scattering (INS) spectra of thiophene adsorbed on MoS2/alumina catalysts are compared with the spectrum of free thiophene. Changes in the vibrational modes of thiophene due to interaction of thiophene with the catalyst are observed. On the sulfided not‐reduced catalyst out‐of‐plane C‐H motions of thiophene are modified. On the reduced catalyst in‐plane motions of α‐H's are also modified. Evidently the thiophene molecules lie flat on the sulfided catalyst and, in addition on the reduced catalyst, bind to the exposed molybdenum centre through ring sulfur with consequent modification of the α‐H motions.
Off‐site Regeneration of Hydroprocessing Catalysts
Authors: Dufresne P. , Brahma N.
Published: September 2010

This paper describes the basic phenomena occurring during oxidative regeneration of hydroprocessing catalysts, as well as laboratory experiments studying the removal of carbon and sulfur as a function of temperature. It was found that carbon is readily eliminated in a single step between 300°C and 450°C. The elimination of sulfur starts as low as 150°C and is terminated only at high temperatures (600°C). The combustion of C and S, however, seems to be limited by an oxygen diffusion effect into the pores of the catalyst. In addition, the evolution of Surface Area (SA) and Dynamic Oxygen Chemisorption (DOC) values versus regeneration temperature applied is discussed. DOC is used to evaluate the dispersion of the active metal‐sulfide phase. DOC and SA measurements are complementary techniques for quality assurance of the regeneration process. A substantial loss of SA is found above 600°C while DOC values begin to decrease at lower temperatures.

The EURECAT regeneration process is described as well as an example of an industrial regeneration.
ETUDE PHYSICO‐CHIMIQUE ET REACTIVITE DES COMLPEXES DE TRANSFERT DE CHARGE ENTRE LES IMINES SUBSTITUEES ET LES P‐BENZOQUINONES
Authors: Abdaoui Mohamed , Messadi Djelloul , Dewynter Georges‐Francis
Published: September 2010

Substituted imines (donors) and acceptors such as the chloranil (CHL), the bromanil (BRL) and the 2,3‐dichloro‐5,6‐dicyano benzoquinone (DDQ) form charge transfert complexes in the liquid and solid states. Physico‐chemical properties as well as the reactivity of the complexes have been studied.

Complexes maximal wave lengths and their formation constants and the ionization potentials of the donors have been determined by UV‐visible absorption spectrometry. The CTC formation is confirmed by infrared, CNMR, and mass (electronic impact method) spectra. The unexpected formation of the substitution derivatives of the CHL and the BRL has been investigated and explained.
SUR LA SENSIBILITE MAGNETIQUE DES RESONATEURS PIEZOELECTRIQUES
Authors: Gire Alain , Lomaglio Germaine , Théobald Jean‐GÉRard
Published: September 2010

Quartz resonators are influenced by magnetic fields. This is easily observed in strong magnetic fields (0,1 ‐ 0,7 Tesla). The perturbations are mainly due to the magnetic properties of nickel contains of the electrodes, and also to the ΔE effects also called Guillemin effect on the same electrodes.

One can observe also “accidents” which occur in very low fields and for which we call for magnetic resonance. These effects could be due to the magnetic resonance of the nickel metallisation of the electrodes. We examine also the possibility that the presence of paramagnetic centers inside the cristal is responsible of absorption of piezoelectric vibrations. These phenomenon occur by the modulation of the magnetic field caused by the neighbouring of one magnetic center.
X‐RAY ANALYSIS OF PYRROLIZIDINES SYNTHESIZED BY DIASTEREOSELECTIVE α‐CYCLISATION OF CAPTODATIVE OR PUSH‐PULL ENAMINES WITH DIMETHYL ACETYLENEDICARBOXYLATE
Authors: Tinant B. , Feneau‐Dupont J. , Declercq J. P. , De Boeck B. , Jiang S. , Janousek Z. , Viehe H. G.
Published: September 2010

The title reactions lead to unique diastereoisomers of pyrrolizidines 1a [dimethyl 2,3‐dehydro‐1‐methyl‐3‐cyanopyrrolizidine‐1,2‐dicarboxylate] or 1b [dimethyl 2,3‐dehydro‐1‐(ethoxycarbonylmethyl)l‐3–phenyl‐pyrrolizidine‐1,2‐dicarboxylate] with relative stereochemistry (1a: trans; 1b: cis) established by X‐ray diffraction analysis. The heterocycle adopts a different conformation in 1a and 1b.
TUNGSTEN CARBONYL PRECURSORS IN CATALYZED OLEFIN METATHESIS VI. HOMOGENEOUS 2‐PENTENE METATHESIS BY [W(CO)3Cp]2/RnSnX4‐n/iBuALCL2OR AICI3/O2 SYSTEMS
Authors: van Ruyskensvelde S. , Bossuyt A. , Haemers T. , Verdonck L.
Published: September 2010

The catalytic systems [W(CO)3Cp]2/ RnSnX4‐n activated by iBuAICI2 or AICI3 / O2 show high conversion and good selectivity for the metathesis of 2‐pentene. When the system is activated by iBuAICI2, both % conversion and selectivity are optimized with a W/Sn/AI/O2 ratio of 1/1/10/10. For the AICI3‐systems the optimal W/Sn/AI/O2 ratio seems to be 1/1/10/5.

The influence of the coprecursor, RnSnX4‐n, is based on the modulation of the alkyl/halogen balance and Lewis‐acidity of the reaction mixture. The stereoselectivity data of all studied catalytic systems, compare well with those of totally different homogeneous catalytic tungsten systems.
REACTIONS OF DICHLOROACETYLENE WITH PRIMARY ALIPHATIC AMINES
Authors: Pielichowski Jan , Czub Piotr
Published: September 2010

Primary aliphatic amines are good nucleophilic reagents which easily react with dichloroacetylene (DCA). The reactions of DCA with primary aliphatic amines have been studied and a mechanism of these reactions has been proposed and discussed.
SYNTHESE DE NOUVELLES STRUCTURES D'INTERET BIOLOGIQUE RENFERMANT UN BLOC ADAMANTANE PAR MONOALKYLATION ET MONOCARBAMOYLATION L'URACILE DE LA THYMINE ET DU 5‐FLUOROURACILE
Authors: Hedayatullah Mir , Challier Anthony , Roger Annie , Nachawati Imad
Published: September 2010

A novel, efficient, and regioselective route to the potentially active pyrímidines of biological interest bearing cage system derived from adamantane is described utilizing substitution or addition reactions under solid‐liquid phase transfer conditions or by a non‐catalytic procedure.
VOLTAMMETRIC BEHAVIOUR OF IMIDAZOLE AND 2‐METHYLDERIVATIVE WITH PENTACYANOFERRATE II. Ko AND α VALUES
Authors: López V. , Arevalillo A. M.
Published: September 2010

Voltammetric investigation of imidazole and 2‐methyl‐imidazole with pentacyanoferrate II in aqueous solutions has been carried out with a platinum rotating electrode. The kinetic parameters ko and α of these systems have been determined at different pH values.
OXYDATION CATALYTIQUE DU TOLUENE EN PHASE LIQUIDE PAR LE REACTIF DE FENTON FeII‐H2O2 ET LE SYSTEME D'UDENFRIEND MODIFIE FeII‐O2REGENERES PAR VOIE ELECTROCHIMIQUE
Authors: Doidy V. , Carré B. , Bouchoule C. , Barrault J. , Blanchard M.
Published: September 2010

The oxidation of toluene was carried out at room temperature with a Fenton reactant FeII‐H2O2 in a diphase medium and a modified Udenfriend FeII‐O2 system electrochemically regenerated We remarked that the Udenfriend system is much more selective for oxidation products of the methyl group (benzaldehyde, benzyl alcohol) than for the hydroxylation products of the aromatic cycle (ortho‐ and para‐cresols, methyl‐p‐quinone). This tendency is the opposite with a Fenton reactant. Furthermore, it is to be noted that the regeneration of the catalyst results in a significant increase in the activity of the two catalytic systems. As for as the Fenton reactant is concerned, the use of a phase transfering agent (tetrabutylammonium bromide) made the reaction possible and improved the activity of the system.
Pd/AIPO4 CATALYSED SELECTIVE LIQUID‐PHASE HYDROGENATION OF β‐IONONE INTO CIS‐DIHYDROIONONE
Authors: Bouchry Naima , Aune Jean‐Pierre , Rais Taoufiq
Published: September 2010

The liquid‐phase hydrogenation of β‐ionone 1 was carried out at 302 K with 0.205 MPa of initial hydrogen pressure in methanol on Pd/AIPO4 catalyst (2‐3 %). The cis‐dihydroionone 2. was obtained with a 83 % selectivity which is independent of the degree of conversion. The reaction rate depends on the chloride concentration in the catalyst and the reaction selectivity is a function of the support of the Pd. According to the Langmuir‐Hinshelwood kinetic models and the Horiuti‐Polanyi type mechanism, the reaction order with respect to β‐ionone concentration is negative and of one half order with respect to the hydrogen pressure. The comparison with results obtained over Pd/C catalyst and those obtained in the catalytic hydrogenation of α‐ionone suggests that the catalytic hydrogenation of β‐ionone could take place on two different active sites of the Pd.
ADDITION DES DIAZOMETHANE ET DIAZOETHANE ET AUX α‐NITRO PARANITROCINNA‐MATES DE METHYLE ISOMERES GEOMETRIQUES ET A L'α‐NITRO PARANITRO‐BENZYLIDENE ACETONE Z. ETUDE PHYSICOCHIMIQUE ET THERMOLYSE DES PYRAZOLINES OBTENUES
Authors: Piet J. C. , Cailleux P. , Benhaoua H. , Danion‐Bougot R. , Carrié R.
Published: September 2010

Cycloadditions of diazomethane and diazoethane on methyl α‐nitro paranitrocinnamates E and Z lead to corresponding pyrazol‐1‐ines, Relations between stereochemistry (and conformation) of these latter and nature (and stereochemistry) of obtained compounds during their thermolysis are shown. After isomerisation in pyrazol‐2‐ines and removal of HNO2, these pyrazol‐1‐ines give pyrazoles. In comparison, reactions of α‐nitro paranitrobenzylidene acetone Z with CH2N2 and CH3CHN2 are also studied.
OXYDATION DE PYRROL‐1‐INES A L'AIDE DE PERACIDES
Authors: Perrocheau J. , Carrié R.
Published: September 2010

Oxidation of 2‐phenyl pyrrol‐1‐ines with metachloro‐ or paranitro‐perbenzoic acids gives to corresponding nitrones. The photochemical cyclisation leads to bicyclic oxaziridines. Discussion on the stereochemistry of this electrocyclisation has been attempted.
Structural Characterization of Paramagnetic Octahedral Homoscor‐Pionate (Polypyrazolylborate) Cobalt Complexes by 1H and 13C NMR Spectroscopy and by FAB‐Mass Spectrometry
Authors: Aubagnac Jean‐Louis , Claramunt Rosa MarÍA , Elguero JosÉ , Gilles Isabelle , Sanz Dionisia , Trofimenko Sviatoslav , Virgili Albert
Published: September 2010

1H and 13C NMR spectroscopy as well as the FAB mass spectrometry have been applied to six bis[tris(pyrazol‐1‐yl)borates]Co(ll) and one bis[tetrakis(pyrazol‐1‐yl)borate]Co(ll). These octahedral complexes are paramagnetic and it was therefore very difficult to obtain their 13C NMR. The isotropic shifts are very large and characteristic of the different positions of the pyrazole and the boron substituents. FAB‐MS also is an interesting method to characterize these complexes, since they give abundant molecular ions and specific fragmentation.
Reactivite De la N‐Ethoxycarbonyl‐N‐(2,2,2‐Trichloroethylidene)Amine Avec Les Precurseurs De Quelques Diarylnitrilimines et Quelques Arylnitriloxydes
Authors: Belaissaoui Abdelhak , Morpain Claude , Laude Bernard
Published: September 2010

The reaction of diarylnitrilimines 2 with N‐ethoxycarbonyl‐N‐(2,2,2‐trichloroethylidene)amine 1 gives substituted 1,2,4‐triazolines 4. With the arylnitriloxides precursors 3, the cycloaddition reaction competes with a nucleophilic addition leading to a mixture of substituted 1,2,4‐oxadiazoline 6 and ethyl 1‐O‐(a‐chloroaraldoximino)‐2,2,2‐trichloroethylcarbamate 7.
Chlorosulfonic Acid Promotes Unusually Selective Chlorination of 2‐Alkanones with Sulfuryl Chloride. Synthesis of 3,3‐Dichloro‐and 1,1,3,3‐Tetrachloro‐4‐Methyl‐2‐Pentanone
Authors: De Buyck Laurent , Esprit Bart
Published: September 2010

Chloride ions formed during the chlorination of ketones with sulfuryl chloride catalyze the production of chlorine. The phenomenon can be suppressed by addition of chlorosulfonic acid, causing a significant change in the regioselectivity of chlorination of 2‐alkanones. Thus from 4‐methyl‐2‐pentanone in the presence of chlorosulfonic acid and the N,N‐dime‐thyloctylammonium salt the 3,3‐dichloroketone was obtained with 76‐78% selectivity (70% isolated) at 40 ± 7°C. After 24h at 90‐105°C the 1,1,3,3‐tetrachloroketone was formed with 90‐92% selectivity and isolated in 80% yield after haloform cleavage of the 1,1,1,3‐isomer. In the absence of chlorine the chlorination involves equilibrated mixtures of enolic intermediates due to competing C‐protonation.
Synthesis of 7‐Bromo‐5‐iodo‐4‐oxo‐1,4‐dihydroquinoline‐2‐carboxylic acid
Authors: Dumont Filip , Slegers Guido
Published: September 2010

The synthesis of 7‐bromo‐5‐iodo‐4‐oxo‐1,4‐dihydroquinoline‐2‐carboxylic acid 7 is described. The synthesis was started from 2,6‐dibromo‐4‐nitroaniline and carried out using a modified Conrad‐Limpach procedure followed by a nucleophilic non‐isotopic exchange.
Studies on the Stereo‐ and Enantioselective Synthesis of 11,12‐epoxy‐Sarcophytol‐A, 11,12‐epoxysarcophytol‐A acetate and 11,12‐epoxy‐cembrene‐C. Synthesis of 5,9,13‐trimethyl‐2‐isopropyl‐12(S),12(S)‐epoxy‐14‐bromo‐2(Z),4(E),8(E)‐tetradecatrienenitrile
Authors: Yue Xiangjun , Li Yulin , Sun Yajie
Published: September 2010

An efficient synthesis of 5,9,13‐trimethyl‐2‐isopropyl‐12(S), 13(S)‐epoxy‐14‐bromo‐2(Z),4(E),8 (E)‐tetradecatrienenitrile, a key intermediate in the synthesis of antitumor cembranoids including 11,12‐epoxy‐sarcophytol‐A, 11, 12‐epoxysarcophytol‐A acetate and 11, 12‐epoxycembrene‐C, was first described through seven step sequence in ∼32% overall yield from E, E‐farnesol.
Nouveaux decontaminants generation “in situ” d'un peracide par action d'un persel sur un initiateur, reactivite de ce peracide vis‐a‐vis du paraoxon
Authors: Lion Claude , Hedayatullah Mir , Charvy Claude , Briand Sylvette , Vincent StÉPhane , Fosset Laurent , Delmas GÉRard , Magnaud Gilbert , Desgranges Michel , Sentenac‐Roumanou Henri
Published: September 2010

The formation of peroxyacids by the reaction of a persalt (sodium percarbonate, sodium perborate,…) with an initiator (TAED, TAGU, NOBS, ISNOBS, PAG, acylsugars) has been developed. The reactivity of these peroxyacids generated “in situ” has been studied in the destruction of paraoxon (0,0‐diethyl O‐paranitrophenylphosphate) with some long chain tetraalkylammonium salts.
Successive‐Substitution Methods in Chemical Equilibrium Calculations. A Novel, Always‐Converging, Usually Fast Algorithm
Authors: Cardinali Mario E. , Giomini Claudio , Marrosu Giancarlo
Published: September 2010

Successive‐substitution methods, long employed for solving difficult cases of numerical problems concerning chemical equilibrium, often generate divergent or slowly convergent sequences. The method in this paper overcomes the first, and often also the second, drawback.
Vibrational Analysis of Thionylimide and Its Isotopes
Authors: Kamaraj V.
Published: September 2010

The potential energy constants of HNSO, DNSO and H 15NSO have been evaluated using Cyvin's W‐matrix method employing the General Valence Force Field. Making use of these constants, the mean‐square amplitudes of vibration, the Coriolis coupling constants and centrifugal distortion constants have also been evaluated and presented here.
Elaboration de Matrices Organiques Photopolymerisables Par le Laser a Argon a 488 et a 514 NM Par Etude de la Polymerisation Des Monomeres Presents Par Spectroscopies IRTF et Uv‐Visible
Authors: Lalèque Nathalie , Giral Louis , Montginoul Claude , Schué FranÇOis , Sledz Joseph
Published: September 2010

In this work we determined the composition of organic matrix which were photopolymerisable at 488 and 514 nm using an argon Laser and which gave the best conversion degree of used monomers (bis‐GMA and teg‐DMA). At 488 nm, camphorquinone and N,N‐dimethylaminoethylmethacrylate (DAM) were respectively used as polymerisation initiator and accelerator. At 514 nm, this system being unable to induce monomer polymerisation, we showed that the use of eosin as photosensitizer, PDO as initiator and DAM or N‐methyldiethanolamine (MDEA) as accelerator were necessary to make the polymerisation possible.
Action de Divers Dienophiles Sur Quelques 2‐(3‐Indolyl)‐1,4‐Naphtoqui‐Nones‐N‐Substituees. Synthese D'une Nouvelle Serie de Naphto‐[2,3‐c]‐Carbazole‐5,13‐Quinones
Authors: Lion Claude , Hocquaux Michel , Amouzegh Patricia , Philippe Michel , Henrion Jean‐Christophe , Caron Emmanuelle , Briand Sylvette
Published: September 2010

Addition of an N‐substituted indole without any substitution in the 2 and 3 positions to 1,4‐naphtoquinone leads to the expected, 2‐(3‐indolyl)‐1,4‐naphtoquinone. The latter reacts with some dienophiles via a Diels ‐ Alder reaction and gives new N‐substituted naphto‐[2,3‐C]‐carbazole‐5‐13‐quinones.
Crystal Structure of 4‐(Bromomethyl)‐5,5‐Dimethyl‐1,3‐Dioxaspiro[5.5]Undec‐2‐One
Authors: Feneau‐Dupont J. , Declercq J. P. , Patiny L.
Published: September 2010

C12H19BrO3, Mr = 291.18, monoclinic, P21/a, a = 12.063(4), b = 19.751(4), c = 12.300(3)Å, β = 115.86(3), V = 2637(1)Å3, Z = 8, Dx = 1.48g.cm−3, MoKα radiation (λ = 0.71069Å). The final R indice is 0.11 for 1641 observed reflections.
Diphenylacetylene from the Base‐Catalyzed Fragmentation of 3,6‐Dihydro‐5,6‐Diphenyl‐3‐Tosyl‐1,3,4‐Oxadiazin‐2‐One
Authors: Allen Aberdeen , Anselme Jean‐Pierre
Published: September 2010

Treatment of 3,6‐dihydro‐5,6‐diphenyl‐3‐tosyl‐1,3,4‐oxadiazin‐2‐one with sodium hydride in THF affords diphenylacetylene in better than 70% yield.
Synthesis and Characterization of Metal Complexes Derived from Potassium 3‐(Benzotriazole‐1‐carbonylmethyl)‐dithiocarbazate
Authors: Xu Peng‐Fei , Liu Zhang‐Lu , Wu Shao‐Zu
Published: September 2010

The preparation and characterization of some dipositive metal ion complexes derived from potassium 3‐(benzotriazole‐1‐carbonylmethyl)‐dithiocarbazate (BCDHK) is reported. The solid complexes of the composition ML · nH2O (M = Mn(II), Ni(II), Cu(II), Cd(II), Zn(II) and Co(II), n = 0,1) and ML2 · 2H2O (M = Pb (II), UO2(VI)), have been characterized on the basis of elemental analyses, IR, UV and TGA. IR spectral data indicate that BCDHK behaves as either a mononegative or binegative ligand and coordinates in a tridentate or bridging tetradentate manner.
X‐Ray K‐Absorption Spectroscopic Studies of Some Cobalt(II) Complexes
Authors: Kekre P. A. , Joshi K. P. , Mishra Ashutosh , Chaturvedi K. K.
Published: September 2010

X‐ray K‐absorption spectra of some cobalt(II) complexes of newly synthesized mannich bases of biological interest have been studied using Seifert X‐ray generator and Cauchois type bent crystal X‐ray spectrograph of 0.4 m radius. The observed X‐ray parameters, e.g. chemical shift, shift of principal absorption maximum, edge‐width, effective nuclear charge and percentage covalency have been used to explain the structure of the complexes, and these parameters have also been correlated with earlier chemical studies.
Regioselective Synthesis of 9‐[(2‐Hydroxyethoxy)Methyl]‐6‐Benzylaminopurine Analogue of Acyclovir
Authors: Taha Mohamed L , Lazrek Hassan B.
Published: September 2010

The 6‐benzylaminopurine 1 has been alkylated with (2‐acetoxyethoxy)methylbromide 3, using trimethylsilylation and phase transfer catalysis procedures. The influence of the base, the solvent and the catalyst were studied. When the solid‐liquid phase transfer catalysis was conducted in tetrahydrofuran in the presence of the potassium tert‐butoxide and 18‐crown‐6, the reaction was regioselective to give 9‐[(2‐acetoxyethoxy)methyl]‐6‐benzylaminopurine 5 in 80% yield.