bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of the Acceleration Effect of 1,10-Phenanthroline on the Rate of Color Change of Xylenol Orange in the Chelatometric Titration of Nickel(II)
Authors: Murayama Teisuke , Takemura Michio 
Published: July 2006

Abstract
The effect in the title was studied kinetically. Experimental results indicate that the color change reaction in the presence of 1,10-phenanthroline proceeds according to a mechanism proposed by Nakagawa and Wada.
Solubility of Transition Metal Complexes in Aqueous Salt Solutions. II. Tris(1,10-phenanthroline)iron(II)Perchlorate in Hydrophobic Salt Solutions
Authors: Miyoshi Katsuhiko , Shimada Chiyori , Yoneda Hayami 
Published: July 2006

Abstract
Solubility of tris(1,10-phenanthroline)-iron(II) perchlorate in water was found to be much increased by the addition of hydrophobic ions. This was interpreted in terms of hydrophobic interaction of the complex cation with hydrophobic ions added.
Mechanism of the Formation of Phenyltolylmethane by the Reaction of Toluene with Phosphorus Trichloride and Oxygen
Authors: Okamoto Yoshiki , Sakurai Hiroshi 
Published: July 2006

Abstract
The formation of phenyltolylmethane by the reaction of toluene with PCl3 and oxygen was shown to proceed by electrophilic attack on toluene by the benzyl cation, resulting from the decomposition of the trichlorobenzyloxyphosphoranyl peroxy radical (PhCH2OPCl3OO·).
Studies on Nitro Sugars. VI. Synthesis of Methyl 2-Deoxy-2-nitro-α-d-glucopyranoside Derivatives
Authors: Takamoto Tetsuyoshi , Sudoh Rokuro 
Published: July 2006

Abstract
Oxidation of methyl 3-O-benzyl-4,6-O-benzylidene-2-oximino-α-d-arabino-hexopyranoside (5) with trifluoroperoxyacetic acid afforded in 76% yield the corresponding 2-nitro-glucopyranoside (6) which has a twist-boat conformation in chloroform.
Phenolysis of 1,1- and 3,3-Dimethylallyl Chlorides. Rates and Product Distributions
Authors: Takeuchi Ken’ichi , Fujii Yoshinobu , Okamoto Kunio 
Published: July 2006

Abstract
The phenolyses of 1,1- and 3,3-dimethylallyl chlorides were shown by kinetic studies to undergo SN1 solvolysis. The distributions of the products, dimethylallyl phenyl ethers and (dimethylallyl)phenols, supported the mechanism that involves both localized ion-pairs and mesomeric ion-pairs.
A Conversion of 4α-Bromoshionan-3-one into D : B-Friedobacchara-1,5(10)-dien-3-one and A Preparation of D : B-Friedo-bacchar-5(10)-en-3-one
Authors: Tachibana Kazuo , Yamada Sachiko , Yamada Sh\={u}z\={o} , Tsuyuki Takahiko , Takahashi Takeyoshi 
Published: July 2006

Abstract
A mixture of D : B-friedo-bacchar-5(10)-en-3-one (2) and D : B-friedo-bacchar-5-en-3-one (4), prepared from 4α-bromoshionan-3-one (3) by the known procedures, was converted into a mixture of 2ξ-bromo-D : B-friedobacchar-5(10)-en-3-one (6) and 2ξ-bromo-D : B-friedo-bacchar-5-en-3-one (7) by bromination with pyridinium tribromide. The mixture (6 and 7) was subjected to dehydrobromination to give D : B-friedo-bacchara-1,5(10)-dien-3-one (5). Hydrogenation of the dienone (5) gave D : B-friedo-bacchar-5(10)-en-3-one (2).
Thermally Stimulated Current in Perylene Crystals
Authors: Sano Mizuka , Egusa Fukuji , Akamatu Hideo 
Published: July 2006

Abstract
A single current peak characteristic of thermally detrapped holes was observed at 220 K, the depth of the traps being determined to be 0.50±0.02 eV. This value showed no apparent correlation with the activation energy for photoconduction, 0.18±0.01 eV.
Kinetics of Ion Exchange in the Chelating Resin Dowex A-1
Authors: Matsuzuru Hideo , Wadachi Yoshiki 
Published: July 2006

Abstract
The kinetics of ion exchanges of Ag+, Zn2+ and Cr3+ at extremely low concentrations on the chelating resin Dowex A-1 has been studied by means of finite volume method. The rate of exchanges for both Ag+ and Zn2+ is dependent on the ionic strength, particle size of the resin and reaction temperature. At higher ionic strength (0.1–0.05) the kinetics is controlled by particle diffusion, whereas at lower ionic one (0.01–0.001) film diffusion is predominant. The apparent activation energy obtained is 3.84 kcal/mol for Ag+ and 3.91 kcal/mol for Zn2+. The exchange rate of Cr3+ obeys a first-order rate equation independent of the ionic strength and particle size of the resin. The apparent activation energy is 15.5 kcal/mol. These results support the view that the ratedetermining step of this reaction is chelate formation reaction.
Proton Hyperfine Splittings in the ESR of Some Alkylphosphine Dimeric Radicals
Authors: Iwaizumi Masamoto , Kishi Takashi , Watari Fumio , Isobe Taro 
Published: July 2006

Abstract
The triplet splittings due to protons were observed for the ESR of the dimeric cation radicals of P(CH3)3, P(CH2CH3)3, and PH(CH3)2; they were formed by the γ irradiation of the rigid CH2Cl2 solutions of these alkylphosphines at 77 K. The observed proton hyperfine splittings for the dimer-cation radicals, [(CH3)3P–P(CH3)3]+ and [(CH3CH2)3P–P(CH2CH3)3]+, were assigned to the hyperfine interaction with two of the methyl and with two of the methylene protons respectively, while those for the [(CH3)2HP–PH(CH3)2]+ radical were assigned to the hyperfine interaction with the two P–H protons. In the former two radicals, the rotations of the methyl and the ethyl groups are restricted. The conformations of the methyl and the ethyl groups have been estimated on the basis of the observed proton hyperfine splittings. The P–H protons of the [(CH3)2HP–PH(CH3)2]+ radical have an extremely large isotropic coupling constant of 58 G; it may be attributed to the direct interaction with the unpaired electron in the anti-bonding σ* orbital of the P–P bond.
Studies of Phase Transitions in Cholesteryl Myristate by Means of Simultaneous Measurements of Polarizing Microscopy and Thermal Analyses
Authors: Sasaki Kunihisa Kazuko , Shinoda Takako 
Published: July 2006

Abstract
An improved DTA furnace and sample cell have been used for accurate DTA measurements and clear polarizing microscopic photographs. The photographs, DTA and TTA curves were obtained simultaneously at different heating or cooling rates for solid-smectic, smectic-cholesteric and cholesteric-isotropic liquid phase transitions in cholesteryl myristate.
Competition of the Two Reaction Mechanisms of Maleic Anhydride Formation in Vapor-Phase Oxidation of Butadiene over Supported Molybdena Catalysts
Authors: Akimoto Masamichi , Echigoya Etsuro 
Published: July 2006

Abstract
Vapor-phase oxidation of butadiene, 2,5-dihydrofuran and furan over supported molybdena catalysts has been investigated with reference to the reaction mechanism and the rate-determining step of maleic anhydride formation from butadiene. Formation of maleic anhydride during the oxidation of butadiene was found to follow two reaction mechanisms, (a) via 2,5-dihydrofuran and furan, and (b) via 2,5-dihydrofuran but not via furan. The energy barrier for the addition of oxygen species to adsorbed butadiene or furan is very high, i.e., 28.9 or 21.9kcal/g-mol, respectively, as compared to that for the oxidative dehydrogenation of the intermediate compounds such as 2,5-dihydrofuran. Formation of 2,5-dihydrofuran is rate-determining in these mechanisms during the oxidation of butadiene to maleic anhydride. The second mechanism plays a more important role in maleic anhydride formation at low temperatures, the role of the first mechanism increasing with a rise in the reaction temperature.
Studies of the Coagulation Flotation of Bentonite and Its Application to the Removal of Co2+ Ions and Fission Products, Ce and Eu
Authors: Kobayashi Koichi , Sato Hiroshi , Kachi Kosei , Nakamura Masao , Sasaki Tsunetaka 
Published: July 2006

Abstract
The regions of dispersion, coagulation precipitation, coagulation flotation, and redispersion were determined for aqueous bentonite-cationic surfactant and bentonite-cationic surfactant-polyacrylamide(PAA) systems. The region of coagulation flotation was markedly extended by the addition of PAA to both the lower and higher concentration regions of the cationic surfactant, hexadecyldimethylbenzylammonium chloride(HDBAC), and to the lower concentration region of bentonite. The phenomenon of coagulation flotation was investigated in detail and was applied to the removal of Co2+ ions and nuclear fission products, 144Ce and 155Eu, from an aqueous solution. The composition of the reagents for the maximum efficiency of bentonite flotation corresponded to that of the maximum efficiency of Co2+-ion flotation. The effect of the pH on the flotation efficiency was studied in particular. The maximum flotation efficiency of 96% was obtained at pH 11 for Co2+ ions, 86% at pH 9.7 for 144Ce, and 93% at pH 10.5 for 155Eu. These radioactive elements were almost completely adsorbed on the surface of bentonite particles and were floated with them in the pH region of the maximum flotation efficiency. It was confirmed that Co2+ ions could be floated also from an extremely low concentration (10−9 mol/l) of Co2+ ions with nearly the same efficiency of flotation and with the additives in the same condition. Co2+ ions could also be effectively removed by using the step-by-step flotation, showing as high a flotation efficiency as 99.8%.
Interfacial Layer between a Mercury Electrode and Dilute Aqueous Solutions of Alkali-Metal Chloride at Potentials of the Cathodic Limiting Current Plateau
Authors: Takahashi Katsuo , Tamamushi Reita 
Published: July 2006

Abstract
The electrochemical properties of the interfacial layer between a DME and dilute aqueous solutions of MCl (M: alkali-metal) at the cathodic limiting current plateau were studied by means of impedance measurements at relatively low frequencies (≤250 Hz). From the frequency and potential dependence of the capacitive and the resistive components of the electrode impedance, the following conclusions were obtained concerning the properties of the interfacial layer under the above condition: (i) when the concentration of cations is extremely low in the vicinity of the electrode surface, the impedance behaves as if the conventional double-layer were absent: (ii) the impedance behavior of the present system can be explained by assuming an equivalent circuit which is given by a series combination of the Warburg impedance for the reduction of M+ and the resistance of solution; and (iii) such an interfacial layer is conventionally called “the Nernst double-layer” and its formation is determined by the mass-transport of the reacting species M+.
Transition-metal Complexes of Pyrrole Pigments. XII. Optical and Magnetic Resonance Spectra of the Cobalt(II) and Nickel(II) Complexes of 1,19-Disubstituted Tetradehydrocorrins
Authors: Murakami Yukito , Sakata Kazunori , Tanaka Yasuhiro , Matsuo Tadashi 
Published: July 2006

Abstract
The cobalt(II) and nickel(II) complexes of 1,19-dimethyl- and 1,19-diethoxycarbonyltetradehydrocorrins were prepared by the template reaction as functioned by metal ions from the corresponding 1,19-disubstituted 1,19-dideoxybiladiene-ac’s. The absorption bands appearing in the energy region greater than 15000 cm−1 were attributed to the π→π* transitions within a ligand molecule. The ligand-field bands were observed in the lower energy region (&lt;15000 cm−1) for the cobalt(II) complexes in which cobalt(II) assumes the C2v coordination symmetry: 2A1←2A1, 2A2←2A1,2B2←2A1, and 2B1←2A1 in an increasing order of energy. The vibrational spectra provided evidences for the formation of the tetradehydrocorrin complexes with perchlorate ion as the counter ion. The angular methyl groups placed at the 1- and 19-positions of tetradehydrocorrins showed the abnormally large up-field shift (2.0 ppm) of their proton signal relative to the parent biladiene-ac’s due to the magnetic anisotropy of the adjacent pyrrole rings A and D. For a 1,19-diethyoxycarbonyltetradehydrocorrin complex, the 1,19-substituents were also placed in the shielding zone of the neighboring pyrrole rings. In the case of the cyclized 2,8,12,18-tetra(2-ethoxycarbonylethyl) derivative, the ethyl ester groups of the 2,18-substituents were presumably placed in a conformational space different from that occupied by those of the 8,12-substituents according to the proton NMR behaviors. The parent biladiene-ac which carries ethoxycarbonyl groups at the 1,19-positions caused a up-field shift of its methine (at bridge positions) proton signal upon cyclization due to the loss of electronic conjugation of carbonyl groups with pyrrole rings, in consistent with the vibrational data. The ESR spectra were measured in chloroform-benzene (2 : 1) at 77 K in the presence and absence of pyridine. The cobalt(II) complexes were identified as of low-spin square-planar type with the unpaired electron in the cobalt dz2 orbital. The coordination capability of 2-ethoxycarbonylethyl groups, which are directly bound to the pyrrole rings in the cyclized metal complex system, was also suggested.
The Resonance Energies of Polyacenes and Related Compounds
Authors: Aihara Jun-ichi 
Published: July 2006

Abstract
The resonance energies of polyacenes were determined on the basis of the additive principle of π-bond energies in nonaromatic compounds. The additive components in the total π-energies for these compounds were reasonably estimated from the infinitely large polyacene. The calculated resonance energies appear to be much improved as compared with those calculated by Hess and Schaad.
An Investigation of the endo Product Selectivity in the Diels-Alder Reaction
Authors: Seguchi Kazuyoshi , Sera Akira , Otsuki Yoshinobu , Maruyama Kazuhiro 
Published: July 2006

Abstract
The Diels-Alder reactions of cyclopentadienes with a variety of substituted ethylenes were carried out, and their reaction rates and the endo : exo isomer ratios of the products were determined. It was shown that the faster reaction is characterized by a higher endo isomer distribution and the existence of a linear correlation between the reaction rate and the endo isomer distribution. The results were interpreted in terms of the concept of secondary orbital interaction in the transition state.
Oxygen-accelerated Generation of the Bromocarbenoid Reagent of Zinc from Diethylzinc and Bromoform. Bromocyclopropanes from Olefins
Authors: Miyano Sotaro , Hashimoto Harukichi 
Published: July 2006

Abstract
Oxygen greatly accelerates the generation of the bromocarbenoid reagent of zinc from diethylzinc and bromoform. Olefins, including cyclohexene, cyclooctene, 1-hexene, cis- and trans-2-butene, isobutene, and 2-methyl-2-butene were bromocyclopropanated in yields of ca. 60–85% using a diethylzinc-bromoform-oxygen system. The bromocarbenoid showed high syn-selectivity for the addition to cyclooctene and cis-2-butene. 9-Bromo-9-deutero[6.1.0]nonane was obtained from cyclooctene using CDBr3. Styrene inhibited the formation of the bromocarbenoid reagent and polymerized under the reaction conditions, suggesting a free radical chain mechanism for the formation of the carbenoid reagent.
Synthesis of o-Ethynylcinnamaldehyde
Authors: Ojima J\={u}ro , Kimura Akihiko , Yokoyama Y\={o}ji , Yokoyama Tai 
Published: July 2006

Abstract
A synthesis of o-ethynylcinnamaldehyde(IV) starting from o-ethynylbenzaldehyde(I) by the Wittig reaction is described.
Nonenzymatic Hydrolysis of Adenosine 5′-Triphosphate in Micellar and Reversed Micellar Systems
Authors: Sen\={o} Manabu , Shiraishi Shinsaku , Araki Koji , Kise Hideo 
Published: July 2006

Abstract
The nonenzymatic hydrolysis of adenosine 5′-triphosphate (ATP) in micellar and reversed micellar system was examined as an approach to elucidate the function of ATPase. In aqueous micellar systems an anionic surfactant does not affect the hydrolysis rate, but a cationic surfactant, cetyltrimethylammonium bromide(CTAB), retards the hydrolysis. This deceleration effect is interpreted to be owing to the pH change or accumulation of hydroxide ions at the cationic micellar-water interface which serves as reaction site. In the reversed micellar system where aqueous ATP phase is solubilized in n-hexane by dodecylammonium propionate(DAP), the hydrolysis rate of ATP is enhanced by several times as compared with that in an aqueous system. Addition of Mg2+ or Ca2+ enhances the hydrolysis rate markedly only in the DAP reversed micellar system. The catalytic effect of the DAP reversed micellar system is discussed with respect to the polarity of water phase solubilized in the core of reversed micelles.
Restricted Rotation Involving the Tetrahedral Carbon. XVII. Isolation of Three “Diastereomeric” Rotamers of a Triptycene Type Compound and Stereoselectivity in the Synthesis
Authors: Yamamoto Gaku , Oki Michinori 
Published: July 2006

Abstract
Three rotameric forms of 2,3-dichloro-9-(1,1-dimethyl-2-phenylethyl)-11,12-bis(methoxycarbonyl)-9,10-dihydro-9,10-ethenoanthracene (3) were isolated as stable entities at room temperature. The structural assignment of the rotamers based on the PMR characteristics. Since the synthesis of 3 produced only the ap form, another reaction involving benzyne was carried out to test the generality of the stereoselectivity. Thus the ap form and the sc form of 2,3-dichloro-9-(1,1-dimethyl-2-phenylethyl)triptycene (4) were prepared separately. Equilibration of isomers of 4 was carried out and the barrier to isomerization was obtained as 36.6 kcal/mol.
Kinetics and Stereochemistry of Alkaline Cleavage of 1,1-Diacetyl-2-arylcyclopropane
Authors: Itoh Osamu , Yamamoto Nobuyuki , Nakano Katsuyuki , Sugita Toshio , Ichikawa Katsuhiko 
Published: July 2006

Abstract
The kinetics and the stereochemistry of alkaline cleavage of several 1,1-diacetyl-2-arylcyclopropanes (1) in ethanol-water mixture are reported. The rates can be expressed approximately by a third order equation, rate=k2[1][OH−]2. With para-substituted derivatives (p-CH3, H, p-Cl and p-Br) of 2-phenyl ring, the reaction constant ρ was obtained as +4.3 by plotting logk2 against normal Hammett σ. At 0 °C, the main products were thermodynamically unstable cis-1-acetyl-2-arylcyclopropanes. The cis to trans ratio in the products decreased with increasing reaction temperature. The reaction mechanism has been discussed in relation to the cleavage reaction of unenolizable acyclic β-diketone. The large ρ value and preferred formation of cis product suggest that the substituent effects of 2-aryl group are transmitted through cyclopropane ring much more effectively to trans direction than to cis direction.
The Chlorination of Norbornene by Metal Chlorides and the Product Isomerization
Authors: Uemura Sakae , Onoe Akira , Okano Masaya 
Published: July 2006

Abstract
The reaction of norbornene with CuCl2, TlCl3·4H2O, PbCl4, SeCl4, SbCl5, and VCl4 in CCl4, CH2Cl2, or CH3CN gave a mixture of nortricyclyl chloride (1), and six isomeric dichloronorbornanes [trans-2,3-(2), exo-2-anti-7-(3), trans-2,5-(4), exo-cis-2,5-(5), exo-cis-2,3-(6), and exo-2-syn-7-(7)], the product distribution depending very much on metal chlorides and reaction conditions. The reactions did not show any participation of a chlorine molecule which may be released from metal chlorides. The ability of SeCl4 and VCl4 to chlorinate olefins was found for the first time. From a synthetic viewpoint CuCl2 was a good reagent for obtaining 2, while TlCl3·4H2O and SbCl5 were recommended for either 3 or 7. The reactions with the following metal chlorides did not give any dichloronorbornanes; SnCl4, BiCl3, TiCl4, FeCl3, NbCl5, TaCl5, and WCl6. It was revealed that isomerization of 2 or 7 to a mixture of 3, 4, and 5 occurred very rapidly by SbCl5 and smoothly by TlCl3·4H2O. The chlorination of norbornene and their products isomerization were mainly explained by assuming a chloronorbornyl cation as an intermediate.
Formations and Reactions of o-Benzoquinone Mono- and Di-imines. I.
Authors: Nogami Takashi , Hishida Tadanori , Yamada Masakazu , Mikawa Hiroshi , Shirota Yasuhiko 
Published: July 2006

Abstract
We have succeeded in obtaining o-benzoquinone monoimine (o-BQMI) and o-benzoquinone diimine (o-BQDI) by oxidizing o-aminophenol (o-AP) and o-phenylenediamine (o-PD), respectively, with freshly prepared lead dioxide at −10 °C in several organic solvents, and also with potassium hexacyanoferrate (III) in an aqueous buffer solution. The formations and reactions of o-BQMI and o-BQDI in aqueous buffer solution were investigated by a stopped flow technique together with a conventional electronic absorption measurements. Both o-BQMI and o-BQDI were formed in the pH range 8–12, and the hydrolysis of o-BQMI to produce o-benzoquinone was found in the pH range 6–8. Both o-BQMI and o-BQDI were found to be unstable at a room temperature to produce 2-aminophenoxazin-3-one (APZ) and 2,3-diaminophenazine (DAP), respectively, as the main products. The formation reactions of APZ and DAP were investigated by observing the spectroscopic course of the reactions in o-BQMI- o-AP and o-BQDI- o-PD system in diethyl ether.
Charge-transfer Intermediate in The Reaction of Thioketone with Nucleophiles
Authors: Ohno Atsuyoshi , Nakamura Kaoru , Uohama Misao , Oka Shinzaburo , Yamabe Tokio , Nagata Shinichi 
Published: July 2006

Abstract
Thiobenzophenone reacts with butyllithium, phenyllithium, and sodium ethoxide in ethanol giving benzhydryl butyl sulfide, benzhydryl phenyl sulfide, and dibenzhydryl disulfide, respectively. On the other hand di-t-butyl thioketone affords 2,2,4,4-tetramethylpentane-3-thiol, 2,2,4,4-tetramethyl-3-phenylpentane-3-thiol, and 2,2,4,4-tetramethylpentane-3-thiol by the reaction with butyllithium, phenyllithium, and sodium ethoxide in ethanol, respectively. Product analyses and tracer experiments with deuteriums have revealed that these reactions proceed through a charge-transfer mechanism.
Reaction of 2,4,6-Tri-t-butylnitrobenzene with Alky Grignard Reagents
Authors: Inagaki Yoshio , Okazaki Renji , Inamoto Naoki 
Published: July 2006

Abstract
Reactions of 2,4,6-tri-t-butylnitrobenzene (1) with alkylmagnesium halides afforded 2,4,6-tri-t-butylaniline (2), N-alkyl-2,4,6-tri-t-butylanilines (3), 6-alkyl-2,4-di-t-butylanilines (4), 4-alkyl-1-hydroxyimino-2,4,6-tri-t-butyl 2,5-cyclohexadienes (5), and 6-alkyl-1-hydroxyimino-2,4,6-tri-t-butyl-2,4-cyclohexadienes (6) depending on the Grignard reagents used. Reduction of the oxime 6 proved to be responsible for the formation of the aniline 4. Comparison of the present reactions with those of 2,4,6-tri-t-butylnitrosobenzene (7) with Grignard reagent, syn-anti-isomzrs of the oxime 6, and the formation mechanisms of the products have been discussed.
Phosphinidenes and Related Intermediates. IV. Reactions of Phosphinothioylidenes with cis- and trans-Stilbene Oxides
Authors: Nakayama Shigenobu , Yoshifuji Masaaki , Okazaki Renji , Inamoto Naoki 
Published: July 2006

Abstract
Phosphinothioylidenes were generated by the reaction of phosphonothioic dichlorides with magnesium. Reactions of phosphinothioylidenes with cis- and trans-stilbene oxides gave 1,3,2-oxathiaphospholane 2-sulfide derivatives (6, 7, 9, and 11) stereospecifically, except for the reaction of phenylphosphinothioylidene with trans-stilbene oxide, along with cis- and/or trans-stilbenes. The formation mechanisms, which involve phenylphosphinothioylidene coordinated by the ethereal oxygen atom, and the conformation of 1,3,2-oxathiaphospholane 2-sulfides were discussed.