bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nucleophilic Reactions of Hexafluoro-1,2-epoxypropane with 1,2-Bifunctional Ethanes
Authors: Kawa Hajimu , Hamouda Hamdy A , Ishikawa Nobuo 
Published: July 2006

Abstract
Reactions between hexafluoro-1,2-epoxypropane and 1,2-bifunctional ethanes were studied. Ethylenediamine, 2-aminoethanol and 2-aminoethanethiol gave corresponding N- and O-pentafluoropropionylated products, while ethylene glycol, 2-mercaptoethanol, and 1,2-ethanedithiol afforded ring closed products, such as 1,4-dioxanone, 1,4-oxathianone, and 1,4-dithianone compounds.
The Thermal Stability of Metal Cation–TCNQ Anion Radical Salts
Authors: Kishimoto Yoshio , Shimotsuma Wataru 
Published: July 2006

Abstract
To study the thermal stability of several metal cation–TCNQ salts (mainly alkali metal salts), the variation in the electrical resistivity and the characteristics of the chemical degradations by heating were measured. Most metal–TNCQ salts do not melt and are not sublimated, but have decomposition points at about 320 °C. Na(TCNQ) has a stable resistivity, even after heating for 500 hours at 200 °C, and is the most stable among the metal–TCNQ salts tested. Metal–TCNQ salts are gradually damaged from the surfaces of the crystalline powders by heating, and the TCNQ, molecule is oxidized, thus losing CN groups. The crystallization process of the TCNQ salts has a great influence upon their thermal stabilities. In the complex salt Cs2(TCNQ)3, the application of d.c. voltage gives rise to the polarization current at a temperature near 200 °C, and the TCNQ molecules tend to migrate in the electric field.
Temperature Dependence of Structural Propensity of 1-Butanol in Water
Authors: Murthy Neriyanuri Manohara , Subrahmanyam Saraswatula Venkata 
Published: July 2006

Abstract
The temperature dependence of structural propensity of 1-butanol has been studied by investigating its effect on the temperature of sound velocity maximum (TVM) in aqueous mixtures of glycerol and pyridine. The structural contribution to the shift in TVM of binary solution, [ΔTstr]exp was found to be positive at low concentrations of 1-butanol for aqueous pyridine solutions whose TVM are 37.6 °C and 23.7 °C. For aqueous glycerol solutions whose TVM is 43.3 °C, [ΔTstr]exp values, in the entire concentration range of 1-butanol studied, are found to be negative. The results indicate that below 40 °C 1-butanol behaves as a structure promoter while above 40 °C it behaves as a structure breaker.
Macroscopic Viscosity and Dielectric Relaxation Process of Ethyl and Butyl Acetates
Authors: Saxena Sudhir Kumar , Shukla Jagdish Prasad , Saxena Mahesh Chandra 
Published: July 2006

Abstract
Dielectric constants and losses have been measured at 9.8 GHz microwave frequency for ethyl and butyl acetates in benzene and benzene–paraffin oil mixtures at 18 °C. The data obtained has been analysed in terms of the two relaxation times τ(1) and τ2 using Higasi, Koga, and Nakamura method and their dependence on the viscosity has been examined. Since the observed values of τ(1)and τ(2) are significantly different, the systems studied represent two Debye type dispersions. It has been found that the relaxation behaviour giving rise to τ(1) in both the ester molecules is not effected to any appreciable extent by the increased macroscopic viscosity. The dielectric relaxation time τ(2) associated with the molecular process lengthens with the increasing macroscopic viscosity of the medium.
The Back-extraction Behavior of Chelate Compounds. III. The Extraction and the Back-extraction of the Metal (II) Diethyldithiocarbamates
Authors: Honjo Takaharu , Imura Hisanori 
Published: July 2006

Abstract
The behavior of trace amounts of cadmium(II), cobalt(II), copper(II), iron(II), mercury(II), manganese(II), nickel(II), lead(II), and zinc(II) in backextraction has been examined in order to establish the basic conditions for the separation of metals as their diethyldithiocarbamates by back-extraction.
Reaction of Bis[1-(2-pyridylazo)-2-naphtholato]cobalt(III) Chloride, [CoIII(pan)2]Cl, with Hyperoxide in Dimethyl Sulfoxide
Authors: Mochizuki Katsura , Imamura Taira , Fujimoto Masatoshi 
Published: July 2006

Abstract
The complex [CoIII(pan)2]+ was found to react in DMSO with hyperoxide, O2−, to give a bivalent cobalt complex [CoII(pan)2]0. The oxidation of [CoII(pan)2]0 to [CoIII(pan)2]+ by oxygen did not proceed in DMSO in the absence of water and/or H+. The standardization of O2− in DMSO were also described.
The Reductive Coupling of Organic Halide Using Hydrazine and a Palladium Amalgam Catalyst. I. The Preparation of Biaryls
Authors: Nakajima Riichiro , Shintani Yuji , Hara Tadashi 
Published: July 2006

Abstract
Iodoarenes could be converted to the corresponding biaryls in high yields by the use of a catalytic amount of a palladium amalgam in place of a palladium–calcium carbonate catalyst in Busch’s reaction. The 2,3′-isomer content in the bitolyls obtained by the homo-coupling of o-iodotoluene was 15% when palladium was used, while it was 1% when a palladium amalgam was used, and the latter was re-usable. The present method is further applicable to some iodoalkanes.
Reactions of Thionitrites or Thionitrates with Carbanions
Authors: Shinhama Koichi , Kim Yong Hae , Oae Shigeru 
Published: July 2006

Abstract
Reaction of several thionitrites (RSNO) or thionitrates (RSNO2) with carbanions such as Grignard reagents, alkyllithium, or the carbanion of diethyl malonate gave C-alkylthio derivatives such as sulfides or diethyl (alkylthio)malonates.
Synthesis Using Allylidenedihydropyridines. VIII. Facile Preparation of 2-Alkylthio-3-vinylpyrazolo[1,5-a]pyridines
Authors: Kakehi Akikazu , Ito Suketaka , Watanabe Kozo 
Published: July 2006

Abstract
Reactions of 1-[bis(alkylthio)methyleneamino]-2-methylpyridinium iodides with activated ethoxymethylene compounds in the presence of alkali gave the corresponding 1-[bis(alkylthio)methyleneamino]-2-allylidene-1,2-dihydropyridines in considerable yields, and their thermolyses in benzene afforded 2-alkylthio-3-vinylpyrazolo[1,5-a]pyridine derivatives.
Diazoalkane Complexes of Molybdenum
Authors: Mizobe Yasushi , Uchida Yasuzo , Hidai Masanobu 
Published: July 2006

Abstract
The hydrazido(2-) complexes [MoX2(NNH2)(PMe2Ph)3] (X=Cl or Br) derived from bis(dinitrogen) complex and HX react with aldehydes or ketones to give a series of diazoalkane complexes [MoX2(\underset←=N–N=CRR′)(PMe2Ph)3].
Raman Study of Aqueous Solutions of Tetraalkylammonium and Bis(tetraalkylammonio) Electrolytes
Authors: Nomura Hiroyasu , Tsukamoto Yoshiaki , Verrall Ronald Ernest , Miyahara Yutaka 
Published: July 2006

Abstract
The Raman and infrared spectra of 1,4-bis(triethylammonio)butane dibromide (J4), 1,10-bis(triethylammonio)decane dibromide (J10), and tetraethylammonium bromide (TEABr) were measured in the solid and dissolved states. The Raman spectra of these salts in the solid and solution states were roughly similar to those of normal paraffins having the same number of skeletal atoms, but some minor differences were found. It was confirmed that molecular conformations of these ions in the solid and solution states are somewhat similar and take the all-trans form, but in main chain of J4 and J10, the gauche form is also observed. In addition, the effects of hydrophobic interaction of these salts in aqueous solution are discussed by comparison of the Raman spectra of OH stretching vibration region of water.
The Gibbs Adsorption Equation for Aqueous Solutions Containing a Weak Base
Authors: Ikeda Shoichi , Ozeki Sumio 
Published: July 2006

Abstract
The Gibbs adsorption isotherm for quaternary systems of water, weak base, HCl or NaOH, and NaCl including a vapor-solution interface is expressed in terms of variations of chemical potentials of neutral components added to make up the solution. Four systems are treated, and the Gibbs convention is introduced in such a way that the surface excess of added water is zero and the surface excesses of solute components are defined. Assuming that the activity coefficients of solute components are unity, the lowering of surface tension is given in terms of variations of total molar concentrations of weak base or its hydrochloride, HCl or NaOH, and NaCl, or of pH of the solution.
Solvent Effect on the Partition Equilibrium of Normal Aliphatic β-Diketones between Heptane and Water–Dimethyl Sulfoxide Mixed Solvents. The Extended McDevit-Long Approach
Authors: Watarai Hitoshi , Suzuki Nobuo 
Published: July 2006

Abstract
The partition equilibria of 7 normal aliphatic (C5-C9) β-diketones were investigated in the two-phase systems of heptane/water–dimethyl sulfoxide (DMSO) mixed solvents at 25 °C. The partition coefficients, P, of the keto and enol forms of the β-diketones were determined, and the linear correlations between logP and the number of carbon atoms in the n-alkyl groups were observed. In general, an increase in the mole fraction of DMSO, Xs, in the mixed-solvent phase caused a lowering of the partition coefficient, while with smaller β-diketones, distinct maxima were observed at Xs\simeq0.2. The solvent effect of the mixed-solvent phase was interpreted on the basis of the extended McDevit-Long theory previously proposed by the present authors.
Molecular Dynamical Studies on Nitrobenzene in Solutions of Tetraethyl and Tetrabutylammonium Bromides
Authors: Nomura Hiroyasu , Tsukamoto Yoshiaki , Miyahara Yutaka 
Published: July 2006

Abstract
The concentration and temperature dependences of the reorientational correlation times of nitrobenzene in solutions of tetraethyl (TEABr) and tetrabutylammonium bromides(TBuABr) have been determined by Raman line shape analysis. Pure liquid nitrobenzene was evaluated for comparison. The reorientational correlation times of nitrobenzene in solutions decreased with increasing concentration of the salts and the apparent activation enthalpy of τor of nitrobenzene in solutions was larger than in that pure nitrobenzene. From the experimental results, the solution structure of TEABr and TBuABr in nitrobenzene are discussed.
Boron Isotope Separation by Ion Exchange Chromatography Using Weakly Basic Anion Exchange Resin
Authors: Sakuma Yoichi , Aida Masao , Okamoto Makoto , Kakihana Hidetake 
Published: July 2006

Abstract
Isotopic plateau displacement chromatography, a useful method for isotope separation is presented. The boric acid band formed in a column of weakly basic anion exchange resin Diaion WA21 can be eluted with pure water. In order to obtain good accumulation of the isotope effect, a series of experiments with different migration length were carried out. The boron-10 enriched part of the boric acid absorbed band was always preceded by the isotopic plateau part, in which the atomic fraction of boron-10 was maintained at its original value. The atomic fraction of boron-10 at the end of the chromatogram increased with migration length, and in the case of 256-m migration, boron-10 was enriched from its original atomic fraction of 19.84 to 91.00%, the separation factor S being constant irrespective of migration length: S=1.0100±0.0005.
The Light-driven Electron Transfer Reaction of Chlorophyll a–Lumiflavin in Micelle
Authors: Yoshimura Akio , Kato Shunji 
Published: July 2006

Abstract
The light-driven electron transfer reaction for the system of chlorophyll a–lumiflavin in micelles was studied by means of flash photolysis. In the sodium dodecyl sulfate micellar solution, the chlorophyll a cation radical appeared on the flash excitation and then decayed by means of a second-order process under aerated conditions as well as under deaerated conditions (the radical was not observed in dioxane). The decay parameter in the aerated solution was smaller than that in the deaerated solution by a factor of twenty. The difference in the decay parameter was explained in terms of the function of the surface charge of micelles. In the deaerated solution, the chlorophyll a cation radical decays by means of a reaction with lumiflavin semiquinone of no charge; in the aerated solution, however, it decays by means of a reaction with the O2\ewdot produced by the electron transfer from lumiflavin semiquinone to oxygen. The latter decay reaction is retarded by the charge on the micelles.
Sound Velocity, Density, and Compressibility in Solutions of Hexamethylphosphoric Triamide in H2O and D2O
Authors: Lyashchenko A K , Goncharov V S , Iijima Toshiro , Uedaira Hisashi , Komiyama Jiro 
Published: July 2006

Abstract
Sound velocity and density measurements for H2O and D2O solutions of hexamethylphosphoric triamide (HMPT), [(CH3)2N]3PO at 25 °C have been carried out. The concentration dependence of the molar volumes and adiabatic compressibilities calculated therefrom are interpreted in terms of the water structure. The differences found between the H2O and D2O solutions are similarly explained.
Photooxidation of 2-Hydroxy Acids by Copper(II) Species in Aqueous Solution
Authors: Matsushima Ryoka , Ichikawa Yoshinori , Kuwabara Katsuyuki 
Published: July 2006

Abstract
Ultraviolet irradiation of aqueous lactic, glycolic, or 2-hydroxybutanoic acid in the presence of copper(II) leads to photoredox reaction to give corresponding α-keto acid, aldehyde with evolution of carbon dioxide, and the precipitate of copper(I). The mole ratio of the carbonyl products to the consumption of copper(II) is close to 0.5. Oxidative decarboxylation dominates at pH&gt;1 while the formation of α-keto acids favors at lower pH. The formation of α-keto acids is selectively suppressed by the addition of free radical scavengers. Free radical oxidations of the acids with bromine atom or benzoyl radicals give exclusively α-keto acids. The reaction mechanism has been discussed.
Molecular Structures of Complexes of Trimethylamine with Boron Trichloride and Boron Tribromide as Determined by Gas Electron Diffraction
Authors: Iijima Kinya , Shibata Shuzo 
Published: July 2006

Abstract
The molecular structures of trimethylamine-boron trichloride (CH3)3N·BCl3 and trimethylamine-boron tribromide (CH3)3N·BBr3 were determined from gas electron diffraction and vibrational-spectroscopic data. The molecular parameters and their uncertainties for (CH3)3N·BCl3 were rg(B–Cl)=1.836±0.002 Å, rg(N–B)=1.652±0.009 Å, rg(C–N)=1.497±0.003 Å, rg(C–H)=1.107±0.005 Å, ∠ClBCl=110.9±0.2°, ∠CNC=108.1±0.3°, while those for (CH3)3N·BBr3 were rg(B–Br)=2.001±0.003 Å, rg(N–B)=1.663±0.013 Å, rg(C–N)=1.500±0.005 Å, rg(C–H)=1.095±0.007 Å, ∠BrBBr=110.3±0.3°, ∠CNC=107.8±0.5°. The potential barriers around the N–B bonds in (CH3)3N·BCl3 and (CH3)3N·BBr3 were also estimated to be higher than 18 kcal mol−1 and about 12 kcal mol−1 respectively.
Synthesis of a Partial Sequence of Proinsulin Using the A-Chain of Natural Insulin. II. Synthesis of a Peptide Corresponding to Positions 53–81 of Bovine Proinsulin
Authors: Aiba Hiroko , Shimonishi Yasutsugu 
Published: July 2006

Abstract
For the synthesis of bovine proinsulin, the S-sulfonate of the A-chain of bovine insulin was elongated by two single-step reactions using Boc–Arg(Tos)–ONSu and Boc–Leu–Glu(OBut)–Gly–Pro–Pro–Gln–Lys[Z(2-Cl)]–N3. The S-sulfonate of the Leu–Glu–Gly–Pro–Pro–Gln–Lys[Z(2-Cl)]–Arg–A-chain, corresponding to positions 53–81 of bovine proinsulin, was obtained after removal of the protecting groups. The S-sulfonates of the elongated derivatives of the A-chain were shown to be very soluble not only in water, but also in organic solvents such as DMF and DMSO in the presence of water. Therefore, these S-sulfonates could react with protected peptides in homogeneous solution. Furthermore, the S-sulfonates could easily be purified by ion-exchange chromatography. The S-sulfonates of the A-chain and its elongated derivatives are thus useful intermediates for the synthesis of proinsulin.
Quantitative Study of Metachromasy. The Analysis of the Dye–Polyphosphate Multiequilibrium System by the Principal Component Analysis Method
Authors: Takatsuki Mineo 
Published: July 2006

Abstract
The absorption spectra of three dyes, 9-aminoacridine (AA), Crystal Violet (CV), and Trypaflavine (TF), were measured in the presence of sodium polyphosphate (NaPP). The optical titrations were performed at phosphate residue-to-dye ratios between 26.6 and 2130 for AA, between 42.6 and 788 for CV, and between 53.9 and 1120 for TF. Using a model in which the condensation of dyes to a poly electrolyte and the bound monomer\ightleftharpoons bound aggregate equilibrium in the vicinity of the polymer are assumed, the extended principal component analysis was applied to the observed spectra of each dye–NaPP system. The equilibrium constants and the pure spectra of bound dye species were determined. Both the bound monomer and the bound dimer were present in the AA–NaPP system, while the bound monomer, bound dimer, and bound tetramer were present in both CV– and TF–NaPP systems. In all the cases, the absorption spectrum of the bound monomer showed a slight bathochromic shift. The absorption spectrum of the bound dimer of AA showed a considerable bathochromic shift without any new band, while the spectrum of the bound dimer and bound tetramer of CV and TF showed metachromasy bands in wavelength ranges both shorter and longer than the peak wavelength of free CV and TF.
Theory of A.c. Polarization and A.c. Polarography and Voltammetry of Two-step Surface Redox Reactions
Authors: Kakutani Tadaaki , Senda Mitsugi 
Published: July 2006

Abstract
Theoretical expressions are presented of the a.c. polarization and of the a.c. polarography and voltammetry for a two-step surface redox reaction (Oad+n1e\ightleftharpoonsSad,Sad+n2e\ightleftharpoonsRad) in which the charge transfer reactions take place exclusively between the adsorbed reactants Oad, Sad, and Rad, and all the reactants are adsorbed so strongly that the amount of O, S, or R brought to or removed from the electrode surface can be neglected. The interaction between the adsorbed reactants is assumed to be expressed by Frumkin’s a-parameters. The effect of the double layer impedance is taken into account. Several simplified cases are discussed in detail.
The Crystal and Molecular Structure of Grayanotoxin II
Authors: Furusaki Akio , Hamanaka Nobuyuki , Matsumoto Takeshi 
Published: July 2006

Abstract
The detailed molecular geometry of grayanotoxin II has been examined by means of X-ray crystallographic analysis. The crystals are orthorhombic, with four molecules in a unit cell with dimensions of a=10.040, b=26.517, and c=6.672 Å; the space group is P212121. 1908 unique intensity data were collected on a four-circle diffractometer with LiF-monochromated Cu Kα radiation. The structure was solved by the Monte Carlo direct method, using the 20 strongest reflections as the starting set; the 3rd random phase set led to the correct solution. The R value reached 3.8% by repeated block-diagonal least-squares refinements. The A, B, C, and D rings take envelope, twist-chair, chair, and half-chair conformations respectively. The conformation of the B ring closely resembles the preferred one of cycloheptane itself. The crystal consists of hydrogen-bonded double molecular layers piled parallel to the (010) plane.
A Quantum Chemical Study on the Ion Influence on Linear Water Polymer
Authors: Rode Bernd M , Fujikura Ryo , Fujiwara Shizuo 
Published: July 2006

Abstract
Quantum chemical model calculations have been performed using an STO-3G basis set for linear water polymers under the influence of electrostatically approximated cations and anions. It is found that the influence of the cations on the ligand chains can be described properly as a purely electrostatic interaction from the third water molecule on. The mutual influencing of cation and anion in ion pairs separated by more than one solvent molecule seems to be also a merely electrostatic one. An estimation of the range of these electrostatic forces is given.
The Reaction of cyclo-Triphosphate with l-Valine
Authors: Tsuhako Mitsutomo , Fujita Naoko , Nakahama Akiko , Matsuo Tsuneo , Kobayashi Masamitsu , Ohashi Shigeru 
Published: July 2006

Abstract
The reaction of cyclo-triphosphate(P3m) with l-valine in an aqueous solution was studied by means of anionexchange chromatography, paper chromatography, chemical analysis for phosphorus and valine, IR spectroscopy, and ninhydrin reaction. 1) P3m reacted with l-valine at pH 10–12 to form an unknown compound, the amount of which reached about 22% at pH 12 and about 9% at pH 10. This compound decomposed into orthophosphate(P1) and valine at a lower pH. 2) The unknown compound was proved to be a P1-derivative of valine, (Remark: Graphics omitted.), which has a P–N bond in its molecule. 3) In the reaction of P3m with l-valine at pH 10, in addition to the unknown compound, small amounts of tetra(P4) and pentaphosphate(P5) were produced. 4) The disappearance rate of P3m in this reaction was first-order, and its rate constants were 0.317 and 0.138 d−1 at pH 12 and 10 respectively at room temperature. 5) Short-chain phosphates, such as P1 pyro (P2), and triphosphate(P3), did not react with l-valine at all. 6) The mechanism of the reaction of P3m with l-valine was discussed.
The Reductive Acylation of Organic Disulfides with Aldehydes under Photochemical and Radical Conditions
Authors: Takagi Makoto , Goto Setsuo , Tazaki Masato , Matsuda Tsutomu 
Published: July 2006

Abstract
The irradiation of organic disulfides in aldehyde solvents resulted in the reductive fission of the S–S linkage, giving an equimolar mixture of the corresponding thiol and the thiol acylate in a good yield. The cyclic disulfides gave mono S-acylated dithiols. The reaction proceeded by means of the photo-initiated radical chain mechanism, and AIBN (azobisisobutyronitrile) effected the same reaction under thermal conditions.
Electronic Structures and Conformations of N-Benzylideneanilines. I. Electronic Absorption Spectral Study Combined with CNDO/S CI Calculations
Authors: Akaba Ryoichi , Tokumaru Katsumi , Kobayashi Tsunetoshi 
Published: July 2006

Abstract
The electronic structures and molecular conformations of N-benzylideneaniline and its several derivatives bearing 2-methyl, 2,6-dimethyl, and/or 4-nitro groups on the anilino benzene ring (ring A) have been investigated by electronic absorption spectroscopy combined with CNDO/S CI calculations. The lower energy bands are assigned and the molecular conformations are estimated. The results show that the 4-nitro derivatives as well as the 2,6-dimethyl derivatives take considerably twisted conformations.
Electrochemical Generation of Unstable Nitrogen Species. Part 4. Electrochemical and Chemical Oxidation of Cyclic and Open-chain Diamines. The Formation of Cyclic Hydrazine Derivatives
Authors: Fuchigami Toshio , Iwaoka Tomoyasu , Nonaka Tsutomu , Sekine Taro 
Published: July 2006

Abstract
Intramolecular N,N-coupling by the electrochemical oxidation of cyclic and open-chain diamines such as 3,3,7,7-tetraethylperhydro-1,5-diazocine (1) and N,N-dimethyl-2,2-diethyl-1,3-diaminopropane (2) was investigated with the use of platinum, silver, nickel, and carbon anodes. In the case of 1, cyclic hydrazine derivatives, 3,3,7,7-tetraethyl-1,5-diazabicyclo[3.3.0]octane and 1-(2-ethyl-2-formylbutyl)-4,4-diethyl-4,5-dihydropyrazole, were formed in high current efficiency. In the case of 2, the corresponding hydrazines, 1,2-dimethyl-4,4-diethylpyrazolidine and 1-methyl-3,3-diethyl-4,5-dihydropyrazole, were obtained in low current efficiency, because C–N bond cleavage took place before N,N-coupling. A carbon anode was found to be effective for N,N-coupling of such diamines. Chemical oxidative N,N-coupling of 1 and 2 was studied by using sodium peroxodisulfate and lead tetraacetate.
Catalysis by 12-Heteropolymolybdic Acid. II. Friedel-Crafts-type Reaction of Aromatic Compounds
Authors: Nomiya Kenji , Sugaya Yoshio , Sasa Sadayoshi , Miwa Makoto 
Published: July 2006

Abstract
12-Heteropolymolybdic acid, a heteropolyacid of Keggin-structure, behaves as an effective catalyst of the Friedel-Crafts-type reactions for aromatic compounds, such as alkylation by benzyl chloride and t-butyl chloride, acylation by acetyl chloride, and sulfonylation by tosyl chloride. The catalyst mainly gives para-substituted products for phenol and anisole. The reactions proceed via carbocation-generation mechanism brought about by the strong Brønsted acid.