bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalytic Reduction of 4H-Cyclopenta[def]phenanthrene under Mild Conditions
Authors: Minabe Masahiro , Yamamoto Y\={o}ji , Yoshida Masaaki , Nakada Katsuko , Suzuki Kazuo 
Published: July 2006

Abstract
The catalytic hydrogenation of 4H-cyclopenta[def]phenanthrene over Raney nickel afforded 8,9-dihydro-4H-cyclopenta[def]phenanthrene and 1,2,3,3a-tetrahydro derivative. Under these conditions, di- and tetrahydro compounds were reduced into two diastereomers, cis-3a-cis-9a- and trans-3a-cis-9a-1,2,3,3a,8,9,9a,9b-octahydro-4H-cyclopenta[def]phenanthrene. The reduction over palladium gave a dihydro compound and a platinum catalyst provided products analogous with those obtained over Raney nickel.
Conversion of 2-Sulfinylated 2-Alkenoate Esters to (2E,4E)-2,4-Alkadienoate Esters by Pyrolysis
Authors: Tanikaga Rikuhei , Nozaki Yoshihito , Nishida Masaharu , Kaji Aritsune 
Published: July 2006

Abstract
Thermal reaction of ethyl (2E)-2-phenylsulfinyl-2-alkenoates (E-2) prepared from aldehydes and ethyl 2-phenylsulfinylacetate have been investigated. Refluxing of E-2 or their Z-isomers in xylene resulted in the formation of ethyl (2E,4E)-2,4-alkadienoates accompanied by ethyl (2E)-4-hydroxy-2-alkenoates. Ethyl 2-cycloalkylidene-2-phenylsulfinylacetates were found to be more susceptible to pyrolysis. The enoate esters (2) undergo migration of their carbon-carbon double bond and then [2,3]sigmatropic rearrangement to benzene-sulfenate esters, followed by thermolytic extrusion of a benzenesulfenic acid probably via ethyl (2E)-4-phenyl-sulfinyl-2-alkenoates to afford ethyl (2E,4E)-2,4-alkadienoates.
Palladium Catalyzed C–C Coupling for Synthesis of π-Conjugated Polymers Composed of Arylene and Ethynylene Units
Authors: Sanechika Kenichi , Yamamoto Takakazu , Yamamoto Akio 
Published: July 2006

Abstract
Palladium compounds such as Pd(PPh3)4 and Pd(OAc)2 catalyze polycondensation between dihalo aromatic compounds, X–Ar–X (Ar=p-phenylene, 2,5-thiophenediyl, 9,10-anthracenediyl, 2,6-pyridinediyl, p-benzenedicarbonyl, p-xylene-α,α′-diyl), and acetylenic compounds (p-C6H4(C≡CH)2 or p-C6H4(C≡CMgBr)2). The polymers obtained have high thermal stabilities and most of them show fluorescence. One of the polymers is converted into semiconductors by doping with electron acceptors.
The Reaction of N-Aryl-C-ethoxycarbonylnitrilimine with Olefins
Authors: Shimizu Tomio , Hayashi Yoshiyuki , Nishio Toshiyuki , Teramura Kazuhiro 
Published: July 2006

Abstract
C-Ethoxycarbonylnitrilimines treated with monosubstituted olefins predominantly gave 5-substituted 3-ethoxycarbonyl-2-pyrazolines. From the analysis of the relative rate and regioselectivity of a variety of monosubstituted olefins for the cycloaddition, the nitrilimine is shown to have reactivity and regioselectivity similar to the throughly studied diphenylnitrilimine. The cycloaddition regioselectivity is discussed in terms of frontier orbital energies and coefficients.
Studies of Molecular Complexes of Some II Donors with Iodine by Constant Activity Method
Authors: Shedbalkar Vinay P , Bhat Subray N 
Published: July 2006

Abstract
The iodine complexes of benzene, toluene, o-, m-, p-xylene and mesitylenes in cyclohexane are studied by using constant activity method. The association constants and the other thermodynamic parameters of the complexes are determined and the results are compared with those obtained by using conventional spectral methods. The blue shifted iodine band maxima are determined directly.
Extraction and Spectrophotometric Determination of Iron(III) with N1-Hydroxy-N1,N2-diphenylbenzamidine in Presence of Azide
Authors: Moges Ghirma , Assefa Demirew , Chandravanshi Bhagwan Singh 
Published: July 2006

Abstract
N 1-Hydroxy-N1,N2-diphenylbenzamidine (HDPBA) reacts with iron(III) in the presence of azide to give a violet-coloured complex insoluble in water. The mixed ligand complex having a composition of 1:2:2 (Fe:HDPBA:N3−) is quantitatively extracted into chloroform at pH 2–5. The violet-coloured complex has an absorption maximum at 530 nm with a molar absorptivity of 4900 l mol−1 cm−1. On the basis of this sensitive colour reaction, a highly selective method has been developed for the extraction and spectrophotometric determination of microgram quantities of iron(III). The effect of foreign ions and several experimental variables have been studied. The method is simple, rapid, precise, and free from the regid control of experimental parameters.
XPS Studies of the Platinum Species Photodeposited on Titania from Aqueous Chloroplatinic Acid
Authors: Sungbom Choi , Kawai Maki , Tanaka Kazunori 
Published: July 2006

Abstract
Several Pt/TiO2 catalysts were prepared by photodeposition from aqueous H2PtCl6 in the presence or absence of a CH3COOH–CH3COONa buffer. The examination of these catalysts by X-ray photoelectron spectroscopy (XPS) revealed that the higher the buffer concentration, the more highly reduced the deposited platinum became.
Ring-contracted Crown Ethers: 14-Crown-5, 17-Crown-6, and Their Sila-analogues. Drastic Decrease in Cation-binding Ability
Authors: Ouchi Mikio , Inoue Yoshihisa , Kanzaki Takashi , Hakushi Tadao 
Published: July 2006

Abstract
As compared with symmetrical 3m-crown-m, the ring-contracted(3m–1)-crown-m showed drastic decrease in cation-binding ability, which is attributable not to the diminished cavity size but to the disordered conformation induced by ring contraction.
Mixed Adsorbed Film of 2-(Octylsulfinyl)ethanol with Decylammonium Chloride at Water/Air Interface
Authors: Uryu Shozo , Aratono Makoto , Yamanaka Michio , Motomura Kinsi , Matuura Ryohei 
Published: July 2006

Abstract
The surface tension of the aqueous solution of 2-(octylsulfinyl)ethanol and decylammonium chloride mixture has been measured by changing the total molality and composition of surfactants at 298.15 K under atmospheric pressure. It has been observed that the surface tension decreases with increasing the total molality at a constant composition and with decreasing the composition of decylammonium chloride at a constant total molality. Further the surface tension vs. total molality curve has been found to have a break point at a relatively low concentration. The thermodynamic equations have been developed so as to be applicable to the adsorption of nonionic–ionic mixture and used to calculate the surface density and the surface composition. It has been shown that the surface density vs. molality curve has the discontinuous change caused by the transition from a gaseous to an expanded film. By drawing the two-dimensional phase diagram and comparing it with the diagrams of the ionic–ionic surfactant mixtures, it has been proved that the shape of the phase diagram is affected greatly by the difference in the surface activity between the two surfactants.
Studies of Bitter Peptides from Casein Hydrolyzate. VI. Syntheses and Bitter Taste of BPIc (Val–Tyr–Pro–Phe–Pro–Pro–Gly–Ile–Asn–His) and Its Analogs and Fragments
Authors: Kanehisa Hidenori 
Published: July 2006

Abstract
In order to investigate the relationship between chemical structure and bitter taste, the bitter peptide BPIc (Val–Tyr–Pro–Phe–Pro–Pro–Gly–Ile–Asn–His) isolated from casein hydrolyzate by Minamiura et al. and its analogs and fragments were synthesized. BPIc, whose threshold value of bitter taste was 0.05 mM, was found to be one of the most bitter compounds, like quinine and phenylthiourea. However, [Gly5,6]- and [Gly9,10]-BPIc, and N-terminal octa- and heptapeptide fragments of BPIc possessed much weaker bitterness than BPIc. The results suggested that 5,6-proline and the basic nature of C-terminal are necessary for the strong bitterness exhibited by BPIc.
Syntheses of 2Fe–2S Ferredoxin Model Complexes of Cys-Containing Oligopeptides by Reaction with Fe2S22+ Ion or by Sulfide Incorporation
Authors: Ueyama Norikazu , Ueno Satoru , Nakata Michio , Nakamura Akira 
Published: July 2006

Abstract
The 2Fe–2S ferredoxin model complexes of two peptide ligands, Z–l-Ala–l-Cys–OMe (Z=benzyloxycarbonyl) and Z–l-Cys–l-Ala–l-Ala–l-Cys–OMe, were synthesized from [NMe4]2[Fe2S2Cl4] by addition of triethylamine. These were characterized by absorption, CD, and MCD spectra in dimethyl sulfoxide or N,N-dimethylformamide. Incorporation of inorganic sulfide to the iron(III) complex, [Fe(Z–cys–Ala–Ala–cys–OMe)2]− (rubredoxin models), results in the selective formation of a 2Fe–2S cluster by a controlling ability of the peptides.
Optically Active Anti Head-to-head Coumarin Dimer. Resolution, Absolute Configuration, and Molecular Structure
Authors: Saigo Kazuhiko , Yonezawa Noriyuki , Sekimoto Kazuhiro , Hasegawa Masaki , Ueno Katsuhiko , Nakanishi Hachiro 
Published: July 2006

Abstract
(±)-Anti head-to-head coumarin dimer was successfully resolved into a pair of optically active forms in good yields and in high optical purity by the fractional crystallization of both lactone-opened diamides with optically active 1-phenylethylamine followed by hydrolysis and relactonization. The absolute configuration of (−)589-anti head-to-head coumarin dimer was confirmed to be (3R,3′R,4R,4′R) by X-ray crystal structure analysis, which showed puckering of the cyclobutane ring (32.5°) and some short nonbonded distances (2.15–2.60 Å).
Reaction of Leucocrystal Violet with Tetracyanoethylene and Chloranil II. Solvent Effects
Authors: Nishimura Norio , Motoyama Takushi 
Published: July 2006

Abstract
The proton/deuteron transfer reaction of Leucocrystal Violet(LCV) with tetracyanoethylene(TCNE) and chloranil(CA) in various solvents has been followed spectrophotometrically. It was found that the reaction proceeds slower in polar solvents such as acetonitrile and acetone than in less polar solvents such as chloroform and 1,2-dichloroethane. The rate is remarkably accelerated by pressure indicating probably a substantial polarity increase in the rate processes. The formation of CT complexes was observed at low temperatures. Their nature is presumed to be similar to that of a complex formed by the reaction of CA with N,N-dimethyl-p-toluidine(DMT), and the latter is discussed in connection with the reaction rate of the LCV–TCNE and LCV–CA systems. A possible reaction path is proposed.
Calorimetric Investigation of N-Acyl Amino Acids
Authors: Miyagishi Shigeyoshi , Matsumura Seiichi , Murata Kazuhiko , Asakawa Tsuyoshi , Nishida Morie 
Published: July 2006

Abstract
The melting characteristics of N-acyl amino acids were examined using a differential scanning calorimeter (DSC). The melting-point temperature of N-dodecanoyl l-amino acid increased with the size of its amino acid residue, while the order was opposite for the Dl-amino acids. The racemic derivatives formed racemic compounds in their solid states. Each N-dodecanoyl l-amino acid had a larger enthalpy and entropy-of-fusion than its racemic isomer. Differences in the thermodynamic quantities between the optically active and racemic isomers were larger for N-dodecanoylvaline and -leucine compared with those of N-dodecanoylalanine. A mixture of these molecules were also studied. Each racemic isomer of N-dodecanoylalanine and -leucine partly formed a racemic pair in the liquid state.
Solution Properties of Low Molecular Weight Fractions of Poly(2-vinylpyridine)
Authors: Yoshida Masafumi , Yamaguchi Shinsuke , Sakamoto Noriyuki , Arichi Shizuo 
Published: July 2006

Abstract
The relationships between the weight-average molecular weight Mw and the intrinsic viscosity [η] of poly(2-vinylpyridine) [P2VP] in benzene and methyl alcohol at 25 °C, were investigated by the use of fractions with molecular weights ranging from 2.1×103 to 2.3×104. The exponent ν in the Mark-Houwink-Sakurada equation, [η]=K0Mwν, was 0.5 in both solvents when Mw was lower than about 104. A constant K0 was approximately in accord with Flory’s Kθ value for ordinary high-molecular-weight P2VP, obtained earlier in respective solvents. By measuring [η] for these low-molecular-weight fractions in several solvents at different temperatures, the temperature coefficients of an unperturbed dimension, dln\barr20⁄dT, of this polymer were estimated and averaged to be −2.3×10−3 K−1. These are quite different from the positive values calculated from the Kθ’s by Dondos et al. which were estimated using the extrapolation method for non-θ-solvents. Our results were further corroborated after adding a Kθ value which was directly determined at another θ-state; i.e. in toluene at 63.7 °C, to that in benzene at 16.2 °C published earlier, which was found from phase-separation experiments in this work.
Electronic Spectra of the Aluminum(III) Complexes of 5,10,15,20-Tetraphenylporphin and 2,3,7,8,12,13,17,18-Octaethylporphin
Authors: Kaizu Youkoh , Misu Naoaki , Tsuji Katsuhisa , Kaneko Yoshiaki , Kobayashi Hiroshi 
Published: July 2006

Abstract
Absorption, magnetic circular dichroism (MCD) and emission spectra as well as preparations of the aluminum(III) complexes of 5,10,15,20-tetraphenylporphin (TPP) and 2,3,7,8,12,13,17,18-octaethylporphin (OEP) are presented. On the basis of the spectral observations, the molecular parameters to describe the lowest (π,π*) excited states of a typical metal porphyrin with only minor perturbation by the incorporated tervalent metal ion were determined. The orbital angular momenta in the excited states were evaluated from the MCD spectra as follows: TPPAlCl, Λz=3.0 h in Q00 band, Λz=±0.61 h Ti in B band and OEPAlCl, Λz=±0.61 h Ti in Q00 band, Λz=0.557 h in band. A Davydov splitting of the Soret band observed for the μ-oxo dimer was interpreted in terms of the exciton coupling between two parallel porphyrin chromophores.
Calorimetric and Spectrophotometric Studies on Formation of Copper(II) Chloride Complexes in N,N-Dimethylformamide
Authors: Ishiguro Shin-ichi , Jeliazkova Bojana G , Ohtaki Hitoshi 
Published: July 2006

Abstract
Formation of copper(II) chloride complexes has been studied by calorimetric and spectrophotometric titrations in N,N-dimethylformamide (DMF) containing different ionic media, 0.1 and 0.2 mol dm−3(C2H5)4NClO4 and 1 mol dm−3 LiClO4 at 25 °C. In all the DMF solutions examined, calorimetric and spectrophotometric titration curves were well explained in terms of formation of a series of four mononuclear complexes, [CuCln](2−n)+(n=1–4), and formation constants, enthalpies and entropies of formation of the complexes were determined. Formation constants were determined by both calorimetry and spectrophotometry and most of the values obtained by the different methods were in good agreement each other. Calorimetric titration curves obtained in 0.1 and 0.2 mol dm−3 (C2H5)4NClO4 ionic media were practically the same, but they significantly differed from those obtained in 1 mol dm−3 LiClO4 ionic medium, the result indicating that the formation of copper(II) chloride complexes was more favored in the former ionic media than in the latter. Stepwise enthalpies of formation were positive for [CuCl]+, [CuCl2], and [CuCl3]−, but negative for [CuCl4]2− in the (C2H5)4NClO4 DMF solutions, while the values in the 1 mol dm−3 LiClO4 DMF solution were more negative by 6–8 kJ mol−1 than the respective values in the (C2H5)4NClO4 solutions. A significant difference was also found for stepwise entropies of formation of copper(II) chloride complexes between the ionic media. The ionic medium effect on the formation of the complexes found was ascribed to ion pairing of LiCl in the 1 mol dm−3 LiClO4 DMF solution, ion pairing of (C2H5)4NCl being insignificant in the (C2H5)4NClO4 DMF solutions used. A largely negative ΔH4° and a small ΔS4° values in the (C2H5)4NClO4 DMF solutions suggested that solvation of the [CUCl3]− complex was not strong, and thus, release of solvent molecules from the [CUCl3]− complex did not play an important role for the formation of [CuCl4]2−. Therefore, the enthalpy and entropy of formation of [CuCl4]2−. were mainly attributable to those of desolvation of chloride ions and of bond formation between Cl− and [CuCl3]−. The [CuCl4]2− complex may have no DMF molecules in the primary coordination sphere of the central metal ion within the complex. Electronic spectra of individual copper(II) chloride complexes were determined from spectra at various concentrations of chloride ions by using the formation constants obtained.
Benzylphenol Derivatives as Antioxidants for Autoxidation of Tetralin
Authors: Yamada Fukiko , Nishiyama Tomihiro , Suzuura Yasuki , Yamamura Tatsuo 
Published: July 2006

Abstract
A series of 4-benzylphenols, 2-methyl-4-benzylphenols, 4-methyl-2-benzylphenols and 4-methoxy-2-benzylphenols have been prepared and evaluated as antioxidants for tetralin at 60 °C by means of an oxygen-absorption method. Very good activities have been observed with a series of 4-methoxy-2-benzylphenols. The electrochemical oxidation potentials of these compounds were determined using linear-sweep voltammetry. The antioxidative activities were found to correlate with both the 13C NMR chemical shifts (δ) of the ipso-carbon of the OH substituent and their peak potentials (Ep).
The Syntheses and Absolute Configurations of Nellionol and 5-Dehydronellionol
Authors: Matsumoto Takashi , Imai Sachihiko , Yoshinari Takashi 
Published: July 2006

Abstract
To determine the absolute configurations of C-15 in natural nellionol and 5-dehydronellionol, (15R)-8,11,13-abietatriene-12,16-diol was converted into (15R)-6α,11,12,16-tetrahydroxy-8,11,13-abietatrien-7-one (3a) and (15R)-6,11,12,16-tetrahydroxy-5,8,11,13-abietatetraen-7-one (4a), which were identical with natural products. For direct comparisons with 3a and 4a, (15S)-6α,11,12,16-tetrahydroxy-8,11,13-abietatrien-7-one (3b) and (15S)-6,11,12,16-tetrahydroxy-5,8,11,13-abietatetraen-7-one (4b) were also synthesized from (15S)-8,11,13-abietatriene-12,16-diol. The synthetic 3b and 4b were not identical with the natural products. From the present study, the absolute configurations of nellionol and 5-dehydronellionol were conclusively assigned as 5S,6R,10S,15R (3a) and 10R,15R (4a), respectively.
The Magnetic Field Effects on the Electrolysis of Hexacyanoferrate(II) Oxidation and Hexacyanoferrate(III) Reduction
Authors: Watanabe Takeshi , Tanimoto Yoshifumi , Sakata Tadayoshi , Nakagaki Ryoichi , Hiramatsu Mitsuo , Nagakura Saburo 
Published: July 2006

Abstract
The effects of a magnetic field on electrolytic currents in hexacyanoferrate(II) and hexacyanoferrate(III) solutions were studied under various conditions by means of potentiometry. These effects were observed for a wide range of current densities (10−6–10−3 A/cm2). The results were interpreted in terms of the magnetohydrodynamic effect, including a change in the solution density during electrolysis. The present observation suggests that a magnetohydrodynamic flow strongly affects the electrochemical processes on an electrode surface.
Studies of Quenching Processes in NE-213 and Insta-Gel Liquid Scintillators by Using Pulse Shape Discrimination Technique
Authors: Endo Kazutoyo , Saotome Tadafumi , Tanaka Keiko , Nakahara Hiromichi 
Published: July 2006

Abstract
Quenching processes for different excitation sources such as alpha-particles and electrons in NE-213 and Insta-Gel were studied by the use of the pulse shape discrimination technique and pulse height analysis. The dependence on electron energies of time spectra due to the difference in pulse shape was observed for NE-213 by setting energy windows to Compton scattered electrons. The results were interpreted on the basis of the linear energy transfer of electrons in liquid scintillator solution. The chemical and oxygen quenchings in Insta-Gel were compared with each other by using conversion electrons and alpha-particles. Quenching constants for those particles were found to be the same for each organo halogen compound used, irrespective of the excitation sources used. Paramagnetic quenchings were also examined for such agents as oxygen, Gd3+ (4f7), and Yb3+ (4f13) by using the above two excitation sources in Insta-Gel. Possible mechanisms of their effects on the quenching processes were discussed in terms of the spin conversion between the paramagnetic quencher and the excited solvent.
Immunoassay Using a Metal-complex Compound as a Chemiluminescent Catalyst. V. Continuous Immunoassay by the Use of CLCCIA
Authors: Hara Tadashi , Toriyama Motohiro , Imaki Masakatsu 
Published: July 2006

Abstract
Immunoassay, using as a labeling reagent a synthesized metal-complex compound having catalytic activity for a chemiluminescence reaction, was continuously carried out by the sandwich method. The time necessary for all the processes (including: an immune reaction, B/F separation, a sandwich reaction, and a chemiluminescence reaction) was reduced to 50 min. Human serum albumin in the range of 5 ng to 1 μg could be determined (continuously) up to 5 times by the use of the same column (immobilized with an antibody).
Polarized Raman and Infrared Spectra of Tetramethyl-d12-pyrazine
Authors: Maehara Masayoshi , Nibu Yoshinori , Shimada Hiroko , Shimada Ryoichi 
Published: July 2006

Abstract
Assignments of the normal vibrations of tetramethyl-d12-pyrazine were made based on the polarization behavior of the Raman and infrared bands and also on the normal coordinate calculation. The result ascertains the assignments of the normal vibrations given previously for tetramethylpyrazine.
Enantioface-differentiating Addition of Butyllithium to Acetophenone by the Use of (1S,2S,5S)-3-[(S)-2-Methoxy-1-alkylethylimino]-2-pinanols as Chiral Ligands
Authors: Kawakami Yuhsuke , Aoki Toshiki , Yamashita Yuya 
Published: July 2006

Abstract
Butyllithium and acetophenone gave optically active 2-phenyl-2-hexanol (33% e.e.) in good yield in the presence of (1S,2S,5S)-3-[(S)-2-methoxy-1-alkylethylimino]-2-pinanol (1).
Furan Derivatives. VII. Synthesis of Cyclohepta[cd]benzofurans
Authors: Horaguchi Takaaki , Hiratsuka Naohiro , Tamura Shigeru , Suzuki Tsuneo 
Published: July 2006

Abstract
7-Methoxy-3,4-dihydrocyclohepta[cd]benzofuran and 7-methoxycyclohepta[cd]benzofuran were synthesized.
Role of the Intermediate Layer and Factors Determining Chemical Composition of the Film in the Electroless Ferrite-plating
Authors: Tamaura Yutaka , Tanno Yukitoshi , Abe Masanori 
Published: July 2006

Abstract
This paper describes electroless ferrite-plating on a Cu substrate whose surface is oxidized (the Cu-oxide layer works as an intermediate layer for the plating). Electron-diffraction and cathodic-reduction analyses showed that a Fe3O4 thin layer is formed on the intermediate layer during the initial reaction of the plating. This thin layer grows by the repetition of the adsorption of metal ions to the surface of the layer and the oxidation of the adsorbed FeII ions. Based on the adsorption-equilibrium of the metal ions on the surface of the film, the relationship between the composition of the metal ions adsorbed and that of the metal ions incorporated into the Co-ferrite film was formulated in terms of the concentrations of the metal ions in the reaction solution and the reaction pH. The analysis of the experimental data with this equation showed that the CoII ions are more readily incorporated into the ferrite layer, as the mol ratio of the adsorbed CoII ions to adsorbed iron ions (Rads.) increases, but that a higher Rads. becomes unfavorable for the incorporation.