bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Solubility Phase Diagram Study on Optical Resolution of Bis(ethylenediamine)oxalatocobalt(III) (1+) by l-α-Amino Dicarboxylate(1−)
Authors: Yamanari Kazuaki , Igaki Michihito , Shimura Yoichi 
Published: July 2006

Abstract
The binary and ternary solubility phase diagrams for the system of Δ- and Λ-[Co(ox)(en)2]X (X=l-glutamate (l-Hglu−) and l-aspartate (l-Hasp−)) were determined in water. It was found that the former anion l-Hglu− behaves as an excellent resolving agent for [Co(ox)(en)2]+ but the latter anion l-Hasp− forms a pseudoracemate rac-[Co(ox)(en)2](l-Hasp).
The Platinum Complex-catalyzed Reductive N-Carbonylation of Dinitroarenes to the Biscarbamates
Authors: Watanabe Yoshihisa , Tsuji Yasushi , Takeuchi Ryo 
Published: July 2006

Abstract
Dichlorobis(triphenylphosphine) platinum(II) shows good catalytic activity for the reductive N-carbonylation of dinitroarenes in ethanol in the presence of a Lewis acid and triethylamine. From 2,4-dinitrotoluene, diethyl 4-methyl-1,3-phenylenebiscarbamate is obtained in 50% yield at 190°C under carbon monoxide pressure of 60 kg cm−2.
Studies on Pyrazines. II. A Novel Formation of 2-Aminopyrazine from the Reaction of Pyrazine 1-Oxide with Phosphoryl Chloride
Authors: Sato Nobuhiro , Kobayashi Michio 
Published: July 2006

Abstract
The reaction of pyrazine 1-oxide with phosphoryl chloride gave a 49% yield of 2-chloropyrazine and a small amount of 2-aminopyrazine. The precursor of aminopyrazine was elucidated to be a 1-(2-pyrazinyl)pyrazinium salt. The orientation of substitution in the formation of the salt was determined by reaction of deuterium labelled pyrazine N-oxides with phosphoryl chloride.
N-Allylation of Imides Catalyzed by Palladium(0)
Authors: Inoue Yoshio , Taguchi Masaaki , Toyofuku Masanori , Hashimoto Harukichi 
Published: July 2006

Abstract
Palladium(0)–triphenylphosphine complexes catalyzed the allylic exchange reaction of allylic esters, phenyl ethers, and isoureas with imides such as phthalimide to give N-allylic products. Among them, O-allylic isoureas were most effective in exchanging the allylic group of more complex structure. N-Allylic derivatives were also obtained by the telomerization of butadiene or allene with phthalimide catalyzed by a palladium(0) species.
Effect of Hydrogenation on Solubility of Carbonized Pitch
Authors: Yamada Yoshio , Shiraishi Minoru , Furuta Takeshi , Yamakawa Toshio , Sanada Yuzo 
Published: July 2006

Abstract
The effect of hydrogenation of carbonized pitch on its solubility in quinoline was investigated in connection with structural changes of the pitch during carbonization. Naphtha-tar pitch (NTP) and acenaphthylene were carbonized at 673 and 703 K, respectively, for various periods of time. The pitches thus heat-treated were hydrogenated by BenKeser reaction and the amount of quinoline insolubles (QI) in the hydrogenated pitch was determined. An acenaphthylene pitch (ACP) heat-treated for 24 h was rendered completely soluble into quinoline by the hydrogenation, whereas a considerable amount of insolubles was left in the case of NTP treated for longer residence times than 8 h. This can be explained in terms of the difference in interaction among aromatic molecules constituting the QI components derived from NTP and ACP. ACPs doped with elemental sulfur left a significant quantity of QI after the hydrogenation. The addition of sulfur is considered to form crosslinking bonds between aromatic molecules through hydrogen abstraction by the sulfur. When QI separated from carbonized NTP was hydrogenated, the degree of conversion into quinoline solubles (QS) was low as compared with that for the whole sample of the same NTP. The presence of QS in the pitch plays a very important role for the hydrogenation.
Decomposition of Blue Orthorhombic Hydrogen Molybdenum Bronze, H0.30MoO3, by Heating in vacuo and in Helium Gas
Authors: Sotani Noriyuki , Yoshida Noritetsu , Kawamoto Yoji , Kishimoto Shozo , Hasegawa Masatomo 
Published: July 2006

Abstract
The decomposition process of orthorhombic hydrogen molybdenum bronze, H0.30MoO3, was studied by the temperature programmed decomposition (TPD) technique in vacuo and in helium gas. The only gas liberated during the decomposition was H2O and no other gas was detected. The TPD spectrum above 150 °C was composed of three bands (PII, PIII, and PIV). The PII band corresponded to the process from H0.30MoO3 to H0.21MoO2.95 without any structural change. The PIII band corresponded to the process from H0.21MoO2.95 to H0.06MoO2.88 with the structural change and the PIV band, to the process from H0.06MoO2.88 to MoO2.85.
Temperature Effect on Decay of Ions and Radicals in Supercooled Liquids as Studied by Pulse Radiolysis and γ-Radiolysis: 1-Propanol and Ethanol
Authors: Kato Noriyuki , Miyazaki Tetsuo , Kawai Yukihiro , Fueki Kenji 
Published: July 2006

Abstract
The decay-rate constants, k, of dipentyl disulfide anions or benzyl radicals in 1-propanol and ethanol were measured over a temperature range of 107–230 K by pulse- and γ-radiolysis method. The decay-rate constants were found to range over nine orders of magnitude. The decay kinetics is a composite first-order reaction. Since the decay rates of reaction intermediates observed are diffusion-controlled, the decay-rate constants represent directly the rates of molecular transport in the supercooled liquids. It was found that the temperature dependence of the decay-rate constants could be expressed by the following equation.
log\frackT=−\fracAT–Tg+B,
where T is the absolute temperature, A and B are constants. Tg is the glass transition temperature. The molecular diffusion of the ions or radicals in the supercooled liquids was completely suppressed at the glass transition temperature. The temperature dependence of the decay-rate constant was compared with that of the viscosity of the matrix. It was found that the temperature, at which the molecular diffusion is completely suppressed is much higher than the temperature at which the viscosity is infinite.
Acid Dissociation Constants of Alkyl Xanthic Acids and Formation Constants of Cadmium(II) and Zinc(II) Xanthato Complexes in 1:1 v/v H2O-DMF Medium
Authors: Hayashi Kenjiro , Sasaki Yoshiaki , Inomata Shigehiro , Yanagidani Takagimi 
Published: July 2006

Abstract
The overall formation constants, β3, of cadmium(II) and zinc(II) complexes with alkyl xanthates (O-alkyl dithiocarbonates) were determined by polarography in the 1:1 v/v water–N,N-dimethylformamide mixture. The values of these constants increase in the order, methyl&lt;ethyl&lt;propyl&lt;butyl&lt;2-methylpropyl&lt;1-methylethyl xanthate. This order agrees entirely with the order of the basicity of alkyl xanthates determined by using the kinetic parameter of the acid decomposition of xanthates.
Kinetics of Ligand Exchange of Tris(β-diketonato)iron(III) with Acetylacetone, Trifluoroacetylacetone, and 2-Thenoyltrifluoroacetone in Carbon Tetrachloride
Authors: Sekine Tatsuya , Inaba Kazuho 
Published: July 2006

Abstract
The ligand of tris(β-diketonato)iron(III) with acetylacetone (Hacac), trifluoroacetylacetone (Htfa), or 2-thenoyltrifluoroacetone (Htta) in carbon tetrachloride was exchanged with another ligand among these. The rate was measured in order to learn about the reaction mechanism in this medium; one in which no intermediates with the solvent molecules were expected. From the dependence of the rate on the particular leaving and entering ligand and from the values of ΔH\eweq and ΔS\eweq, it was concluded that in an exchange involving [Fe(acac)3] there is always a proceeding dissociative mechanism and for [Fe(tta)3] and [Fe(tfa)3] with Hacac there is an interchange mechanism. Exchanges with a fluorinated β-diketone is thought to have a character intermediate to these two mechanisms.
Dynamic NMR as a Nondestructive Method for the Determination of Rates of Dissociation. IX. Rates of Dissociative Reactions of the Coordinated Form of [o-(Diethylaminomethyl)phenyl]halodimethyl(or diphenyl)stannanes
Authors: Oki Michinori , Ohira Manabu 
Published: July 2006

Abstract
The coordinated form of [o-(diethylaminomethyl)phenyl]halodimethyl(or diphenyl)stannanes was found to exhibit dynamic behaviors in their 1H NMR spectra. Examination of a series of halogen compounds by total line shape analysis of the diastereotopic methylene proton signals revealed that, at 10 °C, the rates of dissociation were 11.7, 22.9, 28.6, and 73.3 s−1 for fluoro, chloro, bromo, and iodo compounds, respectively: The results are in conformity with the expectation from the electronegativity of halogens. The relatively small differences in the activation parameters in the whole series may include contribution by solvation energies. The diphenyl compound exhibited fast exchange rates relative to the corresponding dimethyl compound. This was attributed to the steric factor rather than the pπ-dπ interaction.
Solvent-extraction Behavior of Molybdenum(VI) with 1,5-Diphenylcarbazone and the Extraction-spectrophotometric Determination of Molybdenum(VI)
Authors: Ohashi Kousaburo , Nagashima Kiichiro , Seita Rumiko , Yamamoto Katsumi 
Published: July 2006

Abstract
The solvent extraction of molybdenum(VI) with 1,5-diphenylcarbazone (Hdpco) into chloroform, benzene, or tributyl phosphate (tbp) was studied. The molar ratio of molybdenum(VI): 1,5-diphenylcarbazone in the complex extracted into chloroform or benzene in the range from 1.0 mol dm−3 HNO3 to pH 1.9 was found to be 1:2. The extracted complex was estimated to be MoO2(dpco)2. On the other hand, molybdenum(VI) may be extracted into tbp as a mixture of MoO2(dpco)2 and MoO2(dpco)(OH)(tbp). The extraction constants, Kex(=[MoO2(dpco)2]o/[Mo(OH)6][Hdpco]o2), were determined to be 7.9×106 and 3.8×108mol−2dm6 for chloroform and benzene respectively. A black complex formulated as MoO2(dpco)2·5H2O was formed. Molybdenum(VI) can be determined over the range from 1.50 to 19.0 μg/10 cm3 within a relative error of ±4%. The interference of diverse ions will be described.
Synthetic Photochemistry. XXVIII. A Photochemical C5-Homologation of 4-Isopropenyltoluene with Methyl 2,4-Dioxopentanoate to Isolaurene and a Formal Synthesis of Cuparene
Authors: Takeshita Hitoshi , Mori Akira , Nakamura Satoshi 
Published: July 2006

Abstract
Starting from the photocycloaddition of methyl 2,4-dioxopentanoate with 4-isopropenyltoluene, isolaurene was synthesized, and its further conversion to 5-cuparenone constituted the formal synthesis of cuparene. For the first time, the proto-(2+2)π cycloadduct, a β-keto cyclobutanol derivative, has been isolated from the product mixture.
Structure-taste Relationships of Aspartyl Tripeptide Esters
Authors: Ariyoshi Yasuo 
Published: July 2006

Abstract
A series of twenty four analogues of l-α–Asp–Gly–Gly–OMe has been synthesized in relation to structural features of sweet peptides. The rule in the structure-taste relationships of dipeptides is held in the sweet aspartyl tripeptide esters. In order for the aspartyl tripeptide esters to be sweet, the second amino acid must have a d-configuration and a small, compact alkyl group (Me, Et, or i-Pr) at R2. An l-configuration of the third amino acid is required for a potent sweet taste. It has been concluded that the small alkyl group at R2 participates in binding with the receptor through a hydrophobic interaction and increases the sweetness potency.
Asymmetric Catalytic Hydrogenations of Chiral α-Keto Amides
Authors: Harada Kaoru , Munegumi Toratane 
Published: July 2006

Abstract
Asymmetric catalytic hydrogenations of chiral pyruvamides were carried out using palladium on charcoal (Pd-C) as a catalyst to give lactamides with the diastereoisomeric purities (d.p.) of up to 62%. It was found that there was a linear correlation between the d.p. and the dielectric constant of the solvents used in the hydrogenations of chiral pyruvamides. The results were explained by employing the chelation model and the adsorption of the phenyl group in the substrate molecule on the catalyst. The temperature effect on the d.p. of the product was also examined. The catalytic hydrogenations of chiral benzoylformamides were also performed to give low d.p. presumably, the chelation complexes of the substrates could not take a predominant conformation with the catalyst.
Theoretical Study of Relaxation Mechanism in Magnetic Field Effects on Chemical Reactions
Authors: Hayashi Hisaharu , Nagakura Saburo 
Published: July 2006

Abstract
External magnetic field and magnetic isotope effects on the dynamic behavior of radical pairs in solutions have been studied theoretically, where the relaxation of their electron spins was taken into account. The decay observed with some radical pairs in micellar solutions under high magnetic fields is successfully interpreted in terms of the relaxation mechanism, and the magnetic field dependence of the relaxation rates is calculated for a model system.
The Specific Heat Capacities of d-Glucose and d-Xylose in Water-Ethanol System
Authors: Kawaizumi Fumio , Sasaki Nobuo , Ohtsuka Yasushi , Nomura Hiroyasu , Miyahara Yutaka 
Published: July 2006

Abstract
Using an isoperibol twin calorimeter the specific heat capacities of solutions of d-glucose and d-xylose dissolved in water–ethanol mixtures (10, 20, 30, and 50 wt% of ethanol) have been measured at temperature close to 30 °C and the apparent molar heat capacity of te solutes φCp has been calculated. Dependence of φCp upon solute concentration varied markedly with the solvent composition but the variation was similar for both solutes. The infinite dilution values of φCp° i.e. Cp,2∞ are higher for d-glucose than for d-xylose at any compositions of the solvent system. The Cp,2∞ decreased first noticeably with the amount of ethanol in the solvent, reaching a minimum value at approximately 20 wt% of ethanol, then it increased. Values of the parameter ΔCp,2∞=Cp,2∞–Cp,2*, where Cp,2* is the specific heat capacity of the solute in the solid state, are negative in 10, 20, and 30 wt% of ethanol, while it is positive in 50 wt%. The values of ΔCp,2∞ have been discussed in its connection with the degree of structuring of the solvents.
Potassium-ion Exchange on α-Hafnium Phosphate
Authors: Tomita Isao , Banju Masaru , Noguchi Katsumi , Nakamura Toshihiro 
Published: July 2006

Abstract
Forward and backward pH titration curves were measured for potassium-ion exchange on crystalline α-hafnium phosphate which had been prepared by the direct-precipitation method. Exchange in each direction proceeded in two steps, and the hysteresis was observed in the region of smaller loadings of the potassium ions. Exchange in the ternary H+–Li+–K+ system was also preliminarily investigated, the selectivity of the potassium and lithium ions was what would be expected from the results of the binary hydrogen ion-alkali metal ion systems.
Synergistic Effect of Alcohol-Benzene Mixtures for Coal Extraction
Authors: Iino Masashi , Matsuda Minoru 
Published: July 2006

Abstract
Coals were extracted with alcohol–benzene mixtures at room temperature. For coals of high oxygen content, Yallourn and Taiheiyo coals, the extraction yields for the mixtures were much greater than those for alcohols and benzene alone. This synergistic effect was more marked for less bulky alcohols: The order was methanol&gt;ethanol&gt;isopropyl alcohol&gt;t-butyl alcohol. The degree of swelling and the apparent density of the coals in alcohols were measured. The results show that smaller alcohols may permeate into pores of the coals more extensively and cause greater swelling than larger alcohols. It is reasonable to consider that this swelling of the coals then facilitates the extraction with benzene or alcohol–benzene mixtures, which are better solvents in solubility for coal molecules than alcohols. For Shin-yubari coal having low oxygen content, no such a synergistic effect was observed, probably due to the lower degree of swelling of this coal.
Ozonization of Triphenylmethane Dyes
Authors: Matsui Masaki , Nakabayashi Hideki , Shibata Katsuyoshi , Takase Yoshimi 
Published: July 2006

Abstract
The reaction of Malachite Green (MG, 1a), a model compound of triphenylmethane dye, with ozone proceeded via two paths. The first path involved an ozone attack at the dimethylamino moiety to give a N-formylmethylamino derivative 4a. The second path produced 4-(dimethylamino)benzophenone (2a) and p-(dimethylamino)phenol (6). Other ozonized products, 3a and 5a were also detected. The following is a discussion of the ozonization mechanism.
Heats of Solution of Bolaform Electrolytes in Water. II. Polymethylenebis(trimethylammonium) Dibromides
Authors: Tamaki Kunio , Furuya Rie 
Published: July 2006

Abstract
The heats of solution of polymethylenebis(trimethylammonium) dibromides [(CH3)3N(CH2)nN-(CH3)3]Br2 (n=3–6, 8, 10, and 12) and alkyltrimethylammonium bromides CnH2n+1N(CH3)3Br (n=2–6) in water were measured at 15, 25, and 35 °C. The hydrophobic character of the polymethylene groups was compared with that of alkyl groups on the basis of the changes in the heat capacity for dissolution, which were obtained from the relation between the heats of solution and the temperature.
Deprotection of 4-Methoxybenzyloxycarbonyl Group with p-Toluenesulfonic Acid in Acetonitrile. Application to a Large-scale Preparation of 7-[d-2-Amino-2-(4-hydroxyphenyl)acetamido]cephalosporanic Acid
Authors: Yamada Hirotada , Tobiki Hisao , Tanno Norihiko , Suzuki Hiroyuki , Jimpo Kiyokazu , Ueda Shinji , Nakagome Takenari 
Published: July 2006

Abstract
The 4-methoxybenzyloxycarbonyl group of 7-[d-2-(4-hydroxyphenyl)-2-(4-methoxybenzyloxycarbonylamino)acetamido]cephalosporanic acid was effectively removed with p-toluenesulfonic acid in acetonitrile. The mechanism of the deprotection is discussed and the role of acetonitrile can reasonably be explained in terms of the Ritter reaction.
Synthesis of 2,4-Di(p-formyl)-α-truxillic Acid by Crystal Engineering
Authors: Nakanishi Fusae , Ishii Michiko , Nakanishi Hachiro 
Published: July 2006

Abstract
p-Formycinnamic acid, which usually crystallizes in either the β-form or γ-form of packing, was converted into its diethyl acetal. The introduction of such bulky groups onto a benzene ring successfully provided us with the α-form of packing, from which the desired photodimer, 2,4-di(p-formyl)-α-truxillic acid (c-2, t-4-bis(p-formylphenyl)-r-1,t-3-cyclobutanedicarboxylic acid) was obtained with a yield of 85–90%.
Reactions of Azoxybenzene with Dichlorocarbene in the Phase-transfer-catalyzed System
Authors: Sekiguchi Shizen , Fujiu Tomohisa 
Published: July 2006

Abstract
Azoxybenzene (1) reacted with dichloro-carbene (2) at 40 °C in the presence of a phase-transfer catalyst (18-crown-6 or tributylamine) in a binary solvent (CHCl3–aqueous KOH), giving 2,2,3,3-tetrachloro-1-phenylaziridine (4), azobenzene (5), and 2-hydroxy-1-phenylbenzimidazole.
Oxidation Products of β-Methyl-substituted δ-Lactones Using Benzeneseleninic Anhydride and Selenium Dioxide
Authors: Matsui Takanao , Tahara Shuji , Nakayama Mitsuru 
Published: July 2006

Abstract
When 9,9-ethylenedioxy-6-methoxycarbonyl-5-methyl-2-oxabicyclo[4.4.0]decan-3-one was treated with benzeneseleninic anhydride and selenium dioxide, the former yielded preferentially the 4,5-dehydrogenated compound (2) together with small amounts of the 5-formyl compound (3) and the contraction product (4) of the δ-lactone ring, while the latter produced solely 2 in a poor yield.
The Mercury Volatilization Rate from Water to the Atmosphere
Authors: Okouchi Shoichi , Sasaki Sokichi , Harano Yoshio 
Published: July 2006

Abstract
The volatilization rate of mercury was studied, together with the oxygen reaeration rate, in a laboratory scale under various mixing conditions. The rates of both mercury and oxygen were controlled by mass transfer in the aqueous phase. The obtained ratio of the mercury-volatilization rate constant to the oxygen-reaeration rate constant was 0.94 at temperatures ranging from 283 to 303. If the oxygen-reaeration rate constant is available in a real-water body or in a wastewater-treatment facility, multiplying its value by the ratio of 0.94 permits the determination of the volatilization rate constant of mercury without the direct measurement of the mercury.
Preferred Orientation of Particles in Reflection-type Powder Diffractometry. Preferred Orientations in Benzamide and α-2-Pyrazinecarboxamide Powders
Authors: Nakata Kazuaki , Sugihara Hiroshi , Mori Shinya , Yamaguchi Hiroshi , Takaki Yoshito 
Published: July 2006

Abstract
An improved method for the determination of the orientation distribution function of a powder consisting of preferentially oriented plate-like and needle-like particles was reported. Using this method, the coarse and fine powders of benzamide and α-2-pyrazinecarboxamide were investigated. It was found that the domains (a domain is defined as a collection of particles having the same preferred orientation plane or axis) of preferentially oriented particles exhibit two distinct changes when undergoing grinding of the powder. One change involves a decrease and the other an increase in volume, indicating that the particles in the domain showing the former change transform into those in the domain showing the latter change following grinding. The increase in volume of the domain can be well explained in relation to the existence of molecular layers connected to each other by weak van der Waals force in the crystal.
Pulse Radiolysis of Cycloserine in Aqueous Solutions. One-Electron Oxidation by OH Radicals
Authors: Tanaka Masako , Sakuma Hiroshi , Kohanawa Osamu , Fukaya Seijun , Katayama Meiseki 
Published: July 2006

Abstract
The reaction of (R)-4-amino-3-isoxazolidinone (cycloserine) with OH radicals was studied in aqueous solutions by optical pulse radiolysis at pHs 6.5–12. It was concluded, from a comparison of the transient spectra with those obtained in a reaction with N3 radicals, that OH radicals attacked at the dissociated peptide group, –N−CO–, and an oxidized radical, –\dotNCO–, was produced through one-electron oxidation. From a kinetic analysis, the reaction was considered to have proceeded by two steps: The first step was the formation of OH adducts, where the rate constant, k(OH+cycloserine), was 8×109 mol−1 dm3 s−1 for the zwitterion form of cycloserine at pH 6.5 and 1.2×1010 mol−1 dm3 s−1 for anion form at pHs 8–10. The second step was the formation of oxidized radicals at a rate of 3–4×106 s−1. These radicals decayed with a second-order rate, suggesting a radical-radical recombination. d-Serine was detected as the major product.
Preparation, Stereochemistry, and Kinetics of Isomerization and Racemization of Acetylacetonato Complexes of Chromium(III) Containing 2,2′-Bipyridine N,N′-Dioxide or Its 3,3′-Dimethyl Derivative
Authors: Kanno Hideaki , Utsuno Shunji , Fujita Junnosuke 
Published: July 2006

Abstract
New acetylacetonato (acac) chromium(III) complexes of the type, [Cr(acac)3−nLn]n+ (n=1 and 2), where L denotes a seven-membered chelate ligand, 2,2′-bipyridine N,N′-dioxide (bpdo) or 3,3′-dimethyl-2,2′-bipyridine N,N′-dioxide (rac- or R-mbdo), were prepared. Optically active [Cr(acac)2(R-mbdo)]+ and [Cr(acac)(R-mbdo)2]2+ yielded only one isomer and were assigned to Δ(λ)(lel) and Δ(λλ)(lel2), respectively, on the basis of the circular dichroism spectra and molecular models. The [Cr(acac)(mbdo)2]2+ complex prepared from rac-mbdo formed two racemates of diastereomers, lel2(Δ(λλ), Λ(δδ)) and lel·ob (Δ(λδ)), Λ(δλ), whereas [Cr(acac)2(bpdo)]+ formed only lel(Δ(λ), Λ(δ)) isomer which was resolved by column chromatography. Both rac- and (−)589[Cr(acac)(bpdo)2](ClO4)2·H2O resolved by a chemical method were found to crystallize in lel2 isomer, but isomerize to the isomer in aqueous solution with the rate of 3.31×10−3 s−1 at 295.2 K, the rate constant for racemization (Δ\ightleftarrowsΛ) being 1.08×10−4 s−1 at 295.2 K. An intramolecular conformational inversion of the bpdo chelate ring for the isomerization and an intramolecular twist mechanism for the racemization were proposed.