bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxidation of Coals in Liquid Phases. IX. Kinetics of the Base-Catalyzed Oxidation of Acetate Ion by Oxygen at Elevated Temperatures
Authors: Wakabayashi Takayoshi , Okuwaki Akitsugu 
Published: July 2006

Abstract
The kinetics of the oxidation of the acetate ion by oxygen have been studied to clarify the mechanism of the formation of oxalate from coal in concentrated alkaline solutions at elevated temperatures. The rate for the oxidation in a nickel reactor in the presence of 3 g of iron powder was expressed as −dmAc⁄dt=k′ mAcmOH2Po2, where k′ is the apparent rate constant, mAc is the molality of acetate ion, mOH is molality of the hydroxide ion, and Po2 is the partial pressure of oxygen. This result indicates that the oxidation of the acetate ion proceeds according to a base-catalyzed mechanism. The activation energy was 160 kJ mol−1. In addition, the rate of oxidation was affected by the coexistence of the metal powder and the oxidation activity in the order Cu&gt; Ni&gt; Co&gt; Mn \fallingdotseq Fe&gt;Cr. The catalytic effect of metal oxides on the rate is discussed.
Regioselective 6-Amination and 6-Arylation of 5,8-Quinolinedione Promoted by Metal Ions
Authors: Yoshida Katsuhira , Ishiguro Miwa , Honda Hiroyuki , Yamamoto Mayumi , Kubo Yuji 
Published: July 2006

Abstract
The effects of some metal ions on the amination and arylation of 5,8-quinolinedione (1) and on the amine displacement of 6-piperidino-5,8-quinolinedione have been investigated. The reaction of 1 with various amines in chloroform or ethanol was specifically promoted by Ni(II) ions to give selectively the corresponding 6(substituted amino)-5,8-quinolinediones. With N,N-dialkylanilines in acetic acid the reaction was strongly promoted by Cu(II) ions to give exclusively 6-arylated products, 6-[p-(dialkylamino)phenyl]-5,8-quinolinediones. The metal chelate complex was proposed as an activated intermediate.
Mechanism of the Carboxylation of Cyclohexanone with Carbon Dioxide Catalyzed by 1,8-Diazabicyclo[5.4.0]undec-7-ene
Authors: Mori Hisakazu 
Published: July 2006

Abstract
The dependence of the rate of carboxylation upon the concentration of the reactant was investigated in dimethyl sulfoxide. The reaction rate depended upon the concentration of cyclohexanone and 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU) in the first order, respectively. The reaction also followed first-order kinetics regarding the CO2 pressure in the range 50–400 Torr. From these reaction characteristics, it is suggested that carboxylation proceeds via a reaction between CO2 dissolved in dimethyl sulfoxide and the anion of cyclohexanone, rather than between the CO2 adduct with DBU and cyclohexanone. The results of carboxylation by the CO2 adduct with DBU and by CO2 dissolved in dimethyl sulfoxide also support the above conclusion. The formation of the cyclohexanone anion by a reaction of cyclohexanone with DBU was verified by the UV spectrum of a solution of concentrated DBU and cyclohexanone.
Carbonylation of Enynes under Hydroformylation Conditions Catalyzed by Rhodium Carbonyl. A New Method for Synthesis of Cyclic Enones
Authors: Doyama Kazuo , Joh Takashi , Shiohara Tomoo , Takahashi Shigetoshi 
Published: July 2006

Abstract
The reactivities of 1-buten-3-yne derivatives toward hydroformylation were studied using a rhodium catalyst. Unexpectedly, cyclopentenone derivatives were obtained in moderate yields together with formylsubstituted dienes and unsaturated lactones. This reaction offers a new method for the catalytic synthesis of cyclopentenones. A mechanism for the cyclic carbonylation of enynes is also discussed.
The Chlorination of Vinyl Compounds in Alcohols
Authors: Shinoda Kiyonori , Yasuda Kensei 
Published: July 2006

Abstract
Upon the chlorination of vinyl compounds in alcohols, the reaction products were composed of 2-alkoxy-1-chloro compound (A), 1-alkoxy-2-chloro compound (B) and vicinal dichloride (C). Various vinyl compounds were chlorinated in alcohols at 40 °C in order to elucidate the effect of their molecular structure on the product distribution. The A/(A+B) was inversely proportional to the relative rate of ordinary chlorination in carbon tetrachloride. The A/(A+B) for the chlorination of allyl chloride in methanol was little affected by the reaction conditions: (1) reaction temperature, (2) mole ratio, and (3) elapse of time. However, the A/(A+B) increased with increasing Es value of the alkyl group of alcohol.
Kinetics of the Oxidation of [N-(2-Hydroxyethyl)ethylenediamine-N,N′,N′-triacetato]chromium(III) by Periodate
Authors: Abdel-Khalek Ahmed A , Elsemongy Mahmoud M 
Published: July 2006

Abstract
The kinetics of oxidation of [CrIII(H2O)(TOH)], (TOH=N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetate) by periodate in aqueous solutions has been found to obey the following equation
Rate=\frack2K6[CrIII]T[IVII]T1+[H+]⁄K5+K6[IVII]T
where k2 is the rate constant for the electron-transfer process, K5 is the equilibrium constant for dissociation of [CrIII(H2O)(TOH)] to [CrIII(OH)(TOH)]−+H+ and K6 is the pre-equilibrium formation constant. The activation parameters are reported. It is proposed that electron transfer proceeds via an innersphere mechanism with the hydroxo ligand of the chromium(III) complex bridging the two reactants.
Studies of the Selective O-Alkylation and Dealkylation of Flavonoids. XI. A New Convenient Method for Synthesizing 3,5,7-Trihydroxy-8-methoxyflavones from 7-Hydroxy-3,5,8-trimethoxyflavones
Authors: Horie Tokunaru , Tsukayama Masao , Kawamura Yasuhiko , Seno Masamichi , Yamamoto Shigeo 
Published: July 2006

Abstract
The 3- or 5-methoxyl group in the ditosylates of 5,7-dihydroxy-3,4′,8-trimethoxy- and 3,7-dihydroxy-4′,5,8-trimethoxyflavones was quantitatively demethylated with anhydrous aluminum bromide in acetonitrile to give the corresponding monohydroxyflavones, which were easily hydrolyzed into 3,5,7-trihydroxy-4′,8-dimethoxyflavone. On the basis of the results, the following convenient method for synthesizing 3,5,7-trihydroxy-8-methoxyflavones from 7-hydroxy-3,5,8-trimethoxyflavones was established. 7-Hydroxy-3,5,8-trimethoxyflavones or their tosylates were demethylated with 5% w/v anhydrous aluminum bromide in acetonitrile to give a mixture of the corresponding 3- and 5-hydroxyflavones. The mixture was tosylated and the resultant mixture was demethylated under the same conditions. The demethylated products were hydrolyzed with anhydrous potassium carbonate in methanol to give the desired 3,5,7-trihydroxy-8-methoxyflavones in high yields.
Synthesis and Structure of the Diterpenoid Peucelinendiol
Authors: Moran Joaquín R , Alcazar Victoria , Grande Manuel 
Published: July 2006

Abstract
The synthesis of peucelinendiol has been carried out starting from geraniol, and using as a key intermediates the anion of phenylthiogeraniol and (−)-geraniol epoxide obtained by the Sharpless procedure. Its structure was stablished as (6S,7R)-7-hydroxymethyl-2,6,10,14-tetramethylpentadeca-2,9,13-trien-6-ol. Isopeucelinendiol, epipeucelinendiol, and epiisopeucelinendiol were also synthesized.
The Magnetic Properties of Copper(II) Alkanoate Adducts with Pyridine and Quinoline Analogues
Authors: Emori Shuji , Ohishi Katsuko , Kurihara Hikari , Muto Yoneichiro 
Published: July 2006

Abstract
Various copper(II) alkanoate adducts with pyridine and quinoline analogues have been prepared, and characterized by means of magnetic susceptibility and IR measurements. The effects of axial ligands on the magnetic moments are discussed on the basis of their basicities and steric requirements.
The Preparation and the Structure of Bis(1,3-dimethylureido)methane
Authors: Ebisuno Toichi , Takimoto Michiaki , Takahashi Miyuki , Shiba Ryuichi 
Published: July 2006

Abstract
A new 1,3-dimethylurea–formaldehyde condensate, bis(1,3-dimethylureido)methane, was prepared and the molecular structure, as determined by X-ray analysis, and possible specific interaction to alkaline metal ions were compared with those of 1,3,5,7-tetramethyltetrahydro-1,3,5,7-tetrazocine-2,6(1H,3H)-dione. Although both structures are different from each other, their UV spectra in aqueous solution show that alkaline metal ions, Li+ and Na+, are caught by both of them.
A Theoretical Study on Bromochlorination
Authors: Yamabe Shinichi , Minato Tsutomu 
Published: July 2006

Abstract
The bromochlorination to ethylene is studied by ab initio MO calculations. The presence of the bridge ion is verified by a transition state (TS) search. The TS geometry is represented as an ion pair. Two mechanistic questions, orientation of Br–Cl and the anti Cl− addition, are discussed in terms of the frontier-orbital theory.
The Baeyer–Villiger Reaction of Polycyclic Aromatic Aldehydes: Preparation of Polycyclic Phenols
Authors: Fujishiro Koichi , Mitamura Shuichi 
Published: July 2006

Abstract
Baeyer–Villiger reactions of such polycyclic aromatic aldehydes as 2-dibenzofurancarbaldehyde with various peroxy compounds have been studied in detail, giving predominantly the corresponding phenols.
New Synthetic Methods and Reagents for Complex Carbohydrates. II. Synthesis of 2-Acylamino-2-deoxy-d-glucopyranose Derivatives by Dimethylphosphinothioic Mixed Anhydride Method
Authors: Inazu Toshiyuki , Hosokawa Hideaki , Amemiya Masahide 
Published: July 2006

Abstract
Dimethylphosphinothioic (Mpt) mixed anhydrides of carboxylic acids were found to be useful for N-acylation of 2-amino-2-deoxy-d-glucopyranose derivatives without protecting the hydroxyl functions. By this method, N-acylation of 2-amino-2-deoxy-d-glucopyranose hydrochloride in methanol was also found to be possible.
Carbonyl Fluoride of Molybdenum (Synthesis and Structural Investigation)
Authors: Misra Sudhindra N , Venkatasubramaniant K 
Published: July 2006

Abstract
Difluorotricarbonylmolybdenum MoF2(CO)3 has been synthesized by selective fluorination of molybdenum carbonyl by xenon difluoride in perfluoro solvents as well as in anhydrous hydrogen fluoride. The titled compound was isolated as an orange yellow solid and its composition was established by elemental analysis. It decomposes very slowly at room temperature, but on heating at 100 °C it decomposes completely to yield molybdenum carbonyl, molybdenum fluoride oxide and molybdenum fluoride. The compound was structurally characterized using IR, mass spectral, and X-ray powder diffraction analysis.
Synthesis, Characterization, and the Thermal Decomposition of Copper(II) Bis(oxalato)cuprate(II) Dihydrate
Authors: Deb Nidhuban , Gogoi Pradip K , Dass Narendra N 
Published: July 2006

Abstract
Copper(II) bis(oxalato)cuprate(II) dihydrate, Cu[Cu(C2O4)2]·2H2O, has been synthesized and characterized by elemental analysis, magnetic moment measurement, and IR, electronic and ESR spectral studies. The low value of magnetic moment (1.57 B.M.) from spin-only value is indicative of the antiferromagnetic spin pairing between two paramagnetic copper(II) ions. The ESR spectrum of the powder showed a single signal with a g value of 2.1. The thermal decomposition in air and nitrogen media was investigated by TG, DTG, and DSC. Some of the decomposition products were identified by spectral, analytical and X-ray powder diffraction studies.
Organophosphorus Analogues and Derivatives of the Natural l-Amino Carboxylic Acids and Peptides. V. Synthesis of Analogues of Plumbemycin A
Authors: Natchev Ivan A 
Published: July 2006

Abstract
Analogues of antibiotic Plumbemycin A were synthesized by an exchange of d-norvaline residue with 1,2,3,6-tetrahydro-1,2-azaphosphorine and by coupling of alanylaspartic acid with N-terminal norvaline. The protecting groups were released by highly selective enzyme hydrolysis.
Reaction of Benzeneseleninyl Chloride with Olefins in the Presence of a Lewis Acid. A Novel One Step Vinylic Chlorination
Authors: Kamigata Nobumasa , Satoh Takeshi , Yoshida Masato 
Published: July 2006

Abstract
In the presence of aluminum chloride benzeneseleninyl chloride was found to be an excellent vinylic chlorinating reagent of olefins under mild conditions. However, such olefins as styrene, trans-stilbene, and trans-1-phenylpropene afforded dichloro adducts under similar conditions. A plausible reaction mechanism involving positive chlorine intermediate is proposed.
Spectral and Biological Studies on Organotin(IV) Complexes of Heterocyclic Benzothiazolines
Authors: Singh Kiran , Singh Ranvir , Tandon Jagdish Prasad 
Published: July 2006

Abstract
The monobasic bidentate benzothiazolines, which were produced by the reaction of 2-mercaptoaniline and the heterocyclic aldehydes e.g., 2-furaldehyde, 2-thiophenecarbaldehyde, 2-pyridinecarbaldehyde, and 3-indolecarbaldehyde, have reacted with dialkyltin dichloride to give colored compounds. These compounds were characterized on the basis of elemental analyses, molar conductance, molecular weight determination, electronic and infrared spectral studies. Multinuclear NMR(1H, 13C, and 119Sn) data suggest trigonal bipyramidal and octahedral geometries for the resulting Me2SnCl(\ {NS}) and Me2Sn(\ {NS})2 type complexes where \ {NS} indicates benzothiazoline ligand, respectively. The fungitoxicity of 2-(2-thienyl)benzothiazoline and its complexes has been evaluated on pathogenic fungi.
Studies in the Extraction of Metals with 3-Phenyl-4-acetyl-5-isoxazolone
Authors: Jyothi A , Rao G N 
Published: July 2006

Abstract
Extraction of manganese(II), iron(II), cobalt(II), nickel(II), copper(II), zinc(II), and cadmium(II) from aqueous solution with 3-phenyl-4-acetyl-5-isoxazolone (HPAI) in 4-methyl-2-pentanone (MIBK) has been studied and the extraction constants have been calculated for all the systems except cadmium(II). Separation factors have been calculated for the separation of metals.
The Asymmetric Diels–Alder Cycloaddition Using Ethyl (−)-(Z)-(R)S-2-Methyl-3-(p-tolylsulfinyl)propenoate: Application to an Enantioselective Synthesis of (+)-epi-β-Santalene
Authors: Arai Yoshitsugu , Yamamoto Masatoshi , Koizumi Toru 
Published: July 2006

Abstract
The Diels–Alder reaction of ethyl (−)-(Z)-(R)S-2-methyl-3-(p-tolylsulfinyl)propenoate (6) with cyclopentadiene gave the cycloadducts 7, 8, and 9 in a high diastereoselective manner. The cycloadduct 7 was transformed into the acetal (−)-25. The racemic 25 was used as an intermediate in the synthesis of (±)-β-santalol. Thus, the chiral acetal (−)-25 should provide a route to (−)-β-santalol. The cycloadduct 8 was converted into (+)-epi-β-santalene in 11 steps.
Molecular Motion in Some Hydrogen-Bonded Complexes of Trichloroacetic Acid as Studied by 35Cl-NQR
Authors: Nogaj Boleslaw 
Published: July 2006

Abstract
The paper presents the results of 35Cl-NQR frequency and spin-lattice relaxation time measurements as a function of the temperature in some solid hydrogen-bonded complexes: Trichloroacetic acid (TCA)–3-cyanopyridine, TCA–4-methylpyridine and [CCl3COO···H···OOCCCl3]−[K]+. The activation energies, Ea, for hindered rotation of CCl3 group of the TCA molecule were determined. Employing the available Ea data for the other complexes of this type a linear dependence between the activation energy and 35Cl–NQR frequency shift was obtained. This dependence allowed us to find Ea=f(ΔpKa) as well as Ea=f′(P) where P is the proton transfer degree. The influence of hydrogen bond on the potential barrier of the rotating CCl3 groups of TCA in the complexes studied is also discussed.
A Conformational Study on Some Thiobenzophenones. Molecular Orbital Calculations
Authors: Abu-Eittah Rafie Hassan , El-Kourashy Abdel-Ghany 
Published: July 2006

Abstract
MO calculations were performed on the different conformers of thiobenzophenone and on the planar conformer of a number of its derivatives using the INDO-CI procedures. A nonplanar conformer with an angle of 15° between the planes of benzene rings was predicted for thiobenzophenone. Dipole moment and charge density were calculated and correlated to the reactivity of the studied molecules. A Gaussian analysis was performed on the spectra of the studied compounds, results compared satisfactorily with the results of MO calculations.
Different Acyl Specificity between Mold and Kidney Acylases: Correlation of Hydrolytic Rate to Molecular Size and Electronegative Property of Acyl Group in Acyl-l-phenylalanine Hydrolysis
Authors: Kang Shinwon , Minematsu Yoshihiro , Shimohigashi Yasuyuki , Waki Michinori , Izumiya Nobuo 
Published: July 2006

Abstract
A series of acyl-l-phenylalanines were hydrolyzed by mold and hog kidney acylases. The formyl was found to be the most susceptible for mold acylase, and the butyryl for kidney acylase, indicating the different preferences of these acylases in molecular size and electronegative property of acyl group of substrates.
The Crystal Structure of a Charge-Transfer Complex of Tetrakis(methylthio)tetrathiafulvalenium Dibromoiodate, TMT-TTF·IBr2
Authors: Honda Kazumasa , Goto Midori , Kurahashi Masayasu , Anzai Hiroyuki , Tokumoto Madoka , Ishiguro Takehiko 
Published: July 2006

Abstract
The crystal structure of the title complex, a semiconductor, has been determined. The space group is P21⁄n, with a=8.207(3), b=11.537(4), and c=21.804(12) Å, β=91.88(5)°, and Z=4. The donor cations assume dimer structures with short intermolecular S···S contacts of 3.43, 3.53, and 3.60 Å.
Pentaamminechromium(III) t2g3 Level Properties as Determined from Vibronic Spectra and Crystal Field Calculations
Authors: Schmidtke Hans-Herbert , Adamsky Heribert , Schönherr Thomas 
Published: July 2006

Abstract
Low temperature (∼5 K) absorption and emission spectra of various halogenopentaamminechromium(III) salts have been recorded at high sensitivity in the intercombination region from pure microcrystalline powders and doped into corresponding rhodium complexes. Zero phonon and vibrational side bands are better resolved than reported in earlier investigations. They depend on the crystal lattice and allow a more detailed analysis of the vibrational fine structure. For carrying out reliable assignments to vibronic energy levels, the influence of the crystalline environment in different salts is found to be of major importance. Ligand field and angular overlap calculations are very helpful for solving the assignment problem, they can reproduce the proposed energy level scheme if symmetry adapted π-orbital expansion coefficients are introduced into the electron repulsion terms.
Halogenation Using Quaternary Ammonium Polyhalides. VII. Iodination of Aromatic Amines by Use of Benzyltrimethylammonium Dichloroiodate(1—)
Authors: Kajigaeshi Shoji , Kakinami Takaaki , Yamasaki Hiromichi , Fujisaki Shizuo , Okamoto Tsuyoshi 
Published: July 2006

Abstract
The reaction of aromatic amines with benzyltrimethylammonium dichloroiodate(1—) in dichloromethane–methanol in the presence of calcium carbonate powder for several hours at room temperature gave selectively iodosubstituted aromatic amines in good yields.
An Improvement of the Anderson Test by the Use of High Performance Liquid Chromatography
Authors: Miyazawa Toshifumi , Yamada Takashi , Kuwata Shigeru 
Published: July 2006

Abstract
The replacement of the N-benzyloxycarbonyl (Z) group in the Anderson peptide (Z–Gly–l/d–Phe–Gly–OEt) by Z–l-Ala and the subsequent separation of the diastereomers of the resulting tetrapeptide by reversed-phase HPLC offer a more convenient version with higher accuracy to the original Anderson test for studying racemization in peptide synthesis.
Atom Trapping Atomic Absorption Spectrometric Determination of Some Trace Elements in Soils, Natural Waters, Seawater, and Bovine Liver
Authors: Lau C M , Ure A M , West T S 
Published: July 2006

Abstract
The operational conditions for the determination of Ag, As, Au, Bi, Cd, Cu, Mn, Pb, Sb, Se, Tl, and Zn by atom trapping atomic absorption spectrometry are summarised. With this technique some of these trace elements can be determined in soils, natural waters, seawater and bovine liver at concentrations that are not possible by the conventional technique of flame AAS. For example, seawater is diluted ten-fold with distilled water to overcome nebulisation problems due to salt concentrations and the trace elements are collected for 2 min in situ in the air-acetylene flame before release and measurement. The attack of sodium on the hot silica atom trap tube in the flame gases is prevented by pre-aspiration of aluminium chloride into the flame, thus depositing a protective film of Al2O3. X-Ray diffraction, infrared spectroscopy, scanning electron microscopy, and spark source mass spectrometry are used to show that the protective alumina film consists of mainly σ alumina with a small amount of θ alumina spheroids of varying sizes &lt;1 μm diameter and is highly pure. The nature of a similarly deposited Fe2O3 film is shown to be a more closely packed and irregular form of hematite with a small content of metallic iron. The results obtained by this simple new technique compare well with those obtained by spark source mass spectrometry and electrothermal AAS with a graphite furnace.
Photochemical Reactions of Phthalazine in 2-Propanol
Authors: Inoue Hiroyasu , Sakurai Tadamitsu , Tomiyama Koichi , Sano Ryo , Oshio Masahiro , Hoshi Toshihiko , Okubo Jun 
Published: July 2006

Abstract
Phthalazine undergoes dual photoreactions to simultaneously give two photoproducts, 1,2-dihydrophthalazine (1) and 1,1′,2,2′-tetrahydro-1,1′-biphthalazine (2), upon ultraviolet light irradiation in 2-propanol under nitrogen. There occurs neither photochemical nor thermal interconversion between 1 and 2; these compounds are formed independently from a common intermediate through different reaction pathways. The results of quenching and sensitization experiments for both the reactions and the phosphorescence emission show that the lowest excited singlet and triplet states of phthalazine participate in the formation of 1 and 2, respectively. The observed photochemical behaviors under various conditions lead us to propose a reaction mechanism: Phthalazine is photoreduced in the S1 state to form 1,2-dihydro-1-phthalazinyl radical. The resulting radical in a solvent cage undergoes a subsequent hydrogen abstraction to form 1. On the other hand, the same radical produced in the T1 state escapes from the solvent cage to cause a dimerization which affords 2.
Photocatalytic Decomposition of 2-Ethoxyethanol on Titanium Dioxide
Authors: Yamagata Sadamu , Baba Ryo , Fujishima Akira 
Published: July 2006

Abstract
The reaction mechanism of the photocatalytic oxidation of 2-ethoxyethanol (Ethyl Cellosolve, EtOCH2CH2OH) on TiO2 powder was investigated by gas chromatography-mass spectrometry (GC-MS), infrared (IR) spectroscopy, and electron spin resonance (ESR) with spin trapping technique. Irradiation of TiO2 powder with UV light in the presence of EtOCH2CH2OH under air led to the formation of ethyl formate, ethanol, acetaldehyde and carbon dioxide. The main product, ethyl formate was different from the product through the reaction pathway proposed before for primary alcohols. It was also different from the product of electrolysis on Pt. Reaction mechanism is proposed based on IR and ESR studies.