bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure of Reaction Products of 5-Nitrosotropolone and Arylamine
Authors: Asao Toyonobu , Imajo Seiichi , Nozoe Tetsuo 
Published: July 2006

Abstract
The structures of abnormal reaction products (1:1 and 1:2) between 5-nitrosotropolone and arylamine are elucidated. The reaction of 5-nitrosotropolone with arylamine (e.g., aniline and p-toluidine) affords initially a bicyclic addition product, having 8-azabicyclo[3.2.1]octane system which could be formed by the attack of the amine on 4- and 1-positions of the tropolone ring. The adduct contains two isomers having syn and anti configuration with respect to the hydroxyimino group. These adducts easily isomerized under alkaline conditions to form lactams having the 6-azabicyclo[3.2.1]octane system, which may have been resulted from skeletal rearrangement of a seven-membered ring to a six-membered one. The former adducts, the 8-azabicyclo[3.2.1]octane system, further react with another mole of arylamine to give 1:2 products containing a lactam moiety via similar skeletal rearrangement.
Double Silylation of 1,4-Bis(trimethylsilyl)butadiyne with Disilanes Using a Palladium Catalyst
Authors: Kusumoto Tetsuo , Hiyama Tamejiro 
Published: July 2006

Abstract
Reaction of 1,4-bis(trimethylsilyl)butadiyne with polychlorodisilanes Si2ClxMe6−x in the presence of a palladium catalyst gives, after methylation, 1,1,4,4-tetrakis(trimethylsilyl)butatriene and/or 1,1,2,4-tetrakis(trimethylsilyl)-1-buten-3-yne selectively. Hydrogenation, hydrosilylation, and oxidation of the obtained butatriene were found to take place at C(1)=C(2) double bond exclusively. The regioselectivity is ascribed to the geminally substituted silyl groups which sterically direct the attack of electrophile and stabilize postulated radical intermediates.
Tertiary Amine-Catalyzed Acyl Group Exchange Reaction of N,O-Diacyl-o-aminophenols. Its Mechanism and Factors Determining the Relative Stability of Acyl Exchanged Isomer Pairs
Authors: Sakurai Tadamitsu , Kojima Shuichi , Inoue Hiroyasu 
Published: July 2006

Abstract
Acyl substituent effects on the equilibrium and rate constants for the acyl group exchange reactions of various N,O-diacyl-o-aminophenols have been investigated in solvents with different polarities. It was found that the relative stability of acyl exchanged isomer pairs is determined solely by the inductive effect of acyl groups, provided that the steric hindrance of acyl substituents bonded to amide nitrogen affects the stability to the same extent. The importance of steric hindrance exerted by a bulky acyl group in determining the relative stability was demonstrated by analyzing the correlation between the standard free energy change (ΔG°) and pKa, which were used as the measure of the relative stability of isomer pairs and of the electron-withdrawing ability of acyl groups, respectively. On the other hand, the logarithms of catalytic rate constants for the acyl migration reactions were correlated well to the pKa values. In addition to this finding, a large negative value of activation entropy ΔS\eweq=−160 J K−1 mol−1) and the Brønsted coefficient β of 0.65 for the reaction of N,O-(acetyl)-(1-naphthoyl) pair of N,O-diacyl-o-aminophenol provide a definitive evidence for the rate-determining proton transfer from this derivative to amine catalyst in the transition state.
1H NMR Study of Conformation of Formyl-l-phenylalanyl-6-deoxy-6-amino-cyclomaltoheptaose That Has Excellent Ability of Chiral Recognition
Authors: Saka Wataru , Yamamoto Yasuhiko , Inoue Yoshio , Chûjô Riichirô , Takahashi Keiko , Hattori Kenjiro 
Published: July 2006

Abstract
N-(N-Formyl-l-phenylalanyl)-6-deoxy-6-aminocyclomaltoheptaose (f-l-Phe-β-CD) is one of CD derivatives with excellent ability of chiral recognition. In order to make clear the mechanism of chiral recognition, the conformation of free f-l-Phe-β-CD has been studied by using 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. From the measurement of 1H homonuclear Overhauser enhancement on the rotating frame, it is concluded that f-l-Phe- residue of the f-l-Phe-β-CD is inserted into its cavity from the upside of primary hydroxyl groups of the macrocyclic ring. Analysis of 1H and 13C spectra of f-l-Phe-β-CD and model compounds of f-l-Phe- residue also support this conclusion. The macrocyclic ring is found to be distorted.
Study of Polarographic Anodic Wave Controlled by the Rate of Precipitation Reaction in the Presence of Citrate Ion
Authors: Kikuchi Kenji , Murayama Teisuke 
Published: July 2006

Abstract
The anodic wave of mercury observed in the presence of citrate ions has been studied by a numerical method previously proposed by us. The anodic current increases with an increase of concentration of citrate ion. The anodic wave does not show any diffusion current plateau. The logarithm of the anodic current is plotted against the electrode potential, giving a straight line with a slope of 53–55 mV/unit. With the numerical method, it becomes clear that the anodic wave is controlled by the rate of precipitation, which is too low to attain equilibrium within a drop life and is independent of the surface area of the precipitates.
Formation of CH3Si8O197− Cubic Octameric Anion in (2-Hydroxyethyl)trimethylammonium Silicate Aqueous Solutions Containing Hydrolysis Products of Methyltriethoxysilane
Authors: Hasegawa Isao , Sakka Sumio 
Published: July 2006

Abstract
CH3Si8O197−, in which a Si(O−)4 unit in the cubic octameric silicate anion (Si8O208−) is displaced by a CH3Si(O−)3 unit, has been formed in aqueous solutions of mixture of hydrolysis and polycondensation products of tetraethoxysilane and methyltriethoxysilane under the presence of (2-hydroxyethyl)trimethylammonium ions. The ammonium ions have not had any significant effects on polymerization of hydrolysis products of methyltriethoxysilane in aqueous solutions and the polymerization has taken place randomly to form a widespread distribution of the species with various structures. The hydrolysis product, however, has taken part in the formation process of the cubic octameric silicate anion with the aid of the organic ammonium cations, resulting in the formation of CH3Si8O197−.
Synthesis and Reaction of Diaminosulfoxonium Salts
Authors: Okuma Kentaro , Higuchi Naotsugu , Kaji Shinji , Takeuchi Hiroshi , Ohta Hiroshi , Matsuyama Haruo , Kamigata Nobumasa , Kobayashi Michio 
Published: July 2006

Abstract
Diaminosulfoxonium salts were prepared by alkylation of sulfonimidamides. Their physical properties were described. Their reaction with bases gave the corresponding ylides and sulfonimidamides. The intramolecular rearrangement of the ylides led to ortho substitution via intermediate cyclohexadienimines. Hydrogen transfer, accompanying rearomatization and the subsequent action of bases gave dihydro-2,1-benzisothiazole derivatives. These ylides were also found to react with aldehydes to afford epoxides in moderate yields.
Photocarboxylation of Naphthalene in the Presence of Carbon Dioxide and an Electron Donor
Authors: Tagaya Hideyuki , Onuki Masatoshi , Tomioka Yoshiki , Wada Yoshinori , Karasu Masa , Chiba Koji 
Published: July 2006

Abstract
Naphthalene was carboxylated to naphthoic acids by the irradiation of naphthalene and a donor in the presence of carbon dioxide. The UV irradiation through Pyrex caused reactions of naphthalene, itself, giving a naphthalene dimer etc. Such undesirable reactions were partly depressed by using a CuSO4 filter solution; the selectivities of naphthoic acids and dihydronaphthalenecarboxylic acid increased from 2.2–9.8 to 12.2–23.0%. To avoid any direct irradiation to naphthalene and naphthoic acids was critical. Their high selectivities, up to 67%, were obtained upon visible light irradiation by using phenazine as a sensitizer. More than 90% of the naphthoic acids was 1-naphthoic acid, which was confirmed by GC and ms.
What Does Hückel MO Method Calculate?—On the Relationship between HMO Energy and the Kinetic Energy of π Electrons
Authors: Ichikawa Hiroshi , Sameshima Keiichiro 
Published: July 2006

Abstract
The Hückel MO energies of linear polyenes (1–9 in Fig. 1)were compared with each energy component of the Hartree–Fock total energy. It was concluded that the Hückel MO energy is closely proportional to the kinetic energy of the π electrons between the 2p AOs. This linear relation held in various types of these (1–43) polyenes. It was also shown that the ratio of the π kinetic energy to the total kinetic energy is almost constant. Thus, we may understand with the help of the virial theorem why the Hückel MO energy represents the total energy. We also give a physical background to the theories of aromaticity/antiaromaticity.
119Sn-Emission Mössbauer Studies on 119mTe and 119Sb in S, Se, and Te
Authors: Ambe Shizuko , Ambe Fumitoshi 
Published: July 2006

Abstract
The valence states of 119Sn produced by the EC decay of diluted 119Sb and 119mTe chemically doped in S, Se, and Te were studied by emission Mössbauer spectroscopy. The Mössbauer spectra of S(119mTe) and Se(119mTe) consist of peaks ascribable to Sn(IV) and to Sn(II) surrounded by S or Se, respectively. The Mössbauer spectra of Te(119Sb) samples show that, though a greater part of the 119Sb atoms are dispersed in the Te matrix after coprecipitation and sublimation, upon slow recrystallization after fusion most of the dispersed 119Sb atoms aggregate to form microcrystals of 119Sb2Te3.
Behavior of I2 and I3− Molecular Units Near the Crystal Surface of CsI and Related Polyiodides. Raman-Spectroscopic Studies
Authors: Odagi Kazumasa , Nakayama Hideyuki , Ishii Kikujiro 
Published: July 2006

Abstract
Raman spectra of CsI3 and Cs2I8 crystals were measured for the samples whose structures were carefully examined. The surface of Cs2I8 samples was found to turn into CsI3 when they were kept in air. The heating effect of laser irradiation was shown to change the spectra of Cs2I8 samples to those of CsI3. These results imply that diffusion of iodine molecules occurs in polyiodide crystals. Then, we monitored the reaction of CsI crystals with iodine vapor, and found that iodine makes the layers of CsI3 and CS2I8 on the surface of CsI crystals. It was also found that nearly free I3− ions are generated near the surface of samples during both the thermal decomposition of Cs2I8 and the reaction of CsI with iodine vapor.
Hydrogenation of Unsaturated Carboxylic Acid Catalyzed by Platinum–Silica Coupled with Alkylsilyl Chloride
Authors: Kuno Hideyuki , Takahashi Kyoko , Shibagaki Makoto , Matsushita Hajime 
Published: July 2006

Abstract
Platinum–silica catalysts coupled with alkylsilyl chloride were prepared for the regioselective hydrogenation of unsaturated compounds. These catalysts were stable in polar solvents. It was found that the carbon–carbon double bond far from a hydrophilic site was more rapidly hydrogenated in this catalyst system.
1H and 19F NMR Relaxations of Electroconducting Polypyrrole and Polythiophene Trifluoromethanesulfonates
Authors: Mizuno Motohiro , Asaji Tetsuo , Nakamura Daiyu , Inoue Michiko B , Inoue Motomichi 
Published: July 2006

Abstract
The NMR relaxation time T1 of 1H and that of 19F were determined for polypyrrole and polythiophene doped with trifluoromethanesulfonate (triflate) or perchlorate ions. The 1H T1 is governed by the paramagnetism of the polymer chains. The 19F T1 of the triflate ions is explained by the combined effect of the F–F dipolar interaction and the electron–nucleus coupling. The activation energy for CF3 reorientation about the C3 axis was 7.5 kJ mol−1 for polypyrrole triflate and 15 kJ mol−1 for the corresponding polythiophene.
Temperature Dependence of the Fluorescence Intensity of 1-Benzyloxy-2-pyridone and Related Compounds
Authors: Sakurai Tadamitsu , Yoshikawa Kazuhiro , Inoue Hiroyasu 
Published: July 2006

Abstract
A quantitative analysis of the temperature dependence of fluorescence intensity of the title compounds in saturated hydrocarbon solvents has revealed that the relevant thermally-activated radiationless process from singlet manifold involves a rotation about the N–O bond in these compounds.
Synthesis and Catalytic Capability of Zeolite-Encapsulated Iron and Manganese Tetramethylporphine Complexes
Authors: Nakamura Makoto , Tatsumi Takashi , Tominaga Hiro-o 
Published: July 2006

Abstract
Iron and manganese tetramethylporphine (TMP) complexes were synthesized within the cages in NaY zeolite. The ligation of porphine to the metals enhanced the capability of ion-exchanged zeolite to oxidize saturated hydrocarbons with hydrogen peroxide.
1H NMR Characterization of the Hydrogen-Bond Network in the Water Complex of Resorcinol-Dodecanal Cyclotetramer
Authors: Tanaka Yasutaka , Aoyama Yasuhiro 
Published: July 2006

Abstract
1H NMR spectroscopy on the water complex of resorcinol-dodecanal cyclotetramer indicates that a bound water molecule and a pair of OH groups on adjacent benzene rings of the macrocycle are strongly NOE correlated, but the proton exchange in the resulting hydrogen-bond network is very slow.
Photoreactions of 2-(Dialkylamino)ethyl Esters of γ-Oxo Acids via Remote Hydrogen Transfer: Influence of the Stability and Conformational Flexibility of the Biradical Intermediate on Its Chemical Behavior
Authors: Hasegawa Tadashi , Mukai Keiko , Mizukoshi Kimiko , Yoshioka Michikazu 
Published: July 2006

Abstract
2-(Dibenzylamino)ethyl 4-phenyl-3-oxobutanoate underwent photocyclization via remote hydrogen migration to give 9-membered azalactones, while 2-(dimethylamino)ethyl 4-phenyl-3-oxobutanoate gave only a polymer. Irradiation of 2-(N-methylbenzylamino)ethyl 4-phenyl-3-oxobutanoate gave azalactones via a benzylic hydrogen transfer. No azalactones via methyl hydrogen migration could be detected. The stability and conformational flexibility of biradical intermediates are important factors in the present photocyclization.
Effect of the Chain Length of N-Alkyl-β-alanine on Their Copper Complex Formation in Aqueous Solution
Authors: Nakamura Akio , Koshinuma Masakatsu , Tajima Kazuo 
Published: July 2006

Abstract
The effects of the chain length of N-alkyl-β-alanine (NAA) (the number of carbon atoms in the alkyl chains; n=0, 2, 4, 6, 8, 10, 12) on the copper(II) complex formation and its properties were investigated. The complex formation constants for two-step reactions were determined by potentiometry using the selective electrodes of copper(II) and hydrogen ions. The values of the complex formation constants decreased with increasing chain length of the alkyl substituents, and became constant for the substituents longer than the butyl group. These results could be explained in terms of a steric hindrance effect of the N-alkyl substituents on these coordination reactions. Each logarithmic function of the solubility and of the solubility product of the 1(Cu):2(NAA)-complexes was found to be expressed, respectively, as a linear function of the number of carbon atoms in the alkyl group. From these data, the standard free energies of the formation and the precipitation of the 1:2-complexes from these constituent ions have been estimated, and a standard free energy diagram was constructed for 1:2-complex formation. It was concluded that the hydrophobic interaction is a driving force which promotes crystalline complex formation from the constituent ions.
Selective Separation of Structurally or Electronically Similar Ethers with MAD
Authors: Maruoka Keiji , Nagahara Sigeru , Yamamoto Hisashi 
Published: July 2006

Abstract
Selective separation of the less hindered or electronically more labile of two different ethers has been accomplished with exceptionally bulky, Lewis acidic MAD by the yield of precipitates as selective Lewis acid-base complexes.
Selective Skeletal Rearrangement of Tricyclo[5.4.0.01,5]undecanes to Tricyclo[5.3.1.01,5]- and [5.4.0.03,8]undecanes
Authors: Kakiuchi Kiyomi , Kumanoya Shuichi , Kobiro Kazuya , Tobe Yoshito , Odaira Yoshinobu 
Published: July 2006

Abstract
An acid-catalyzed rearrangement of tricyclo[5.4.0.01,5]undecan-ll-one gave tricyclo[5.3.1.01,5]undecan-11-one in a nonnucleophilic media and tricyclo[5.4.0.03,8]undecane-7, 8-diol in the presence of a nucleophile, respectively. Tricyclo[5.4.0.01,5]undecan-11-ols also rearranged to tricyclo[5.4.0.03,8]undecan-7-ol. A reductive rearrangement with a hydride transfer of the alcohol gave only tricyclo[5.4.0.03,8]undecane.
Convenient Synthesis of β-Silyl Ketones from β-Stannyl Enol Silyl Ethers via a [1,4] Anionic Rearrangement of Silicon
Authors: Nakahira Hiroyuki , Ryu Ilhyong , Ogawa Akiya , Kambe Nobuaki , Sonoda Noboru 
Published: July 2006

Abstract
The transmetalation (Sn to Li) and [1,4] anionic rearrangement of β-stannyl enol silyl ethers have been achieved, providing a convenient method for synthesis of β-silyl ketones.
Comparison between Intra- and Intermolecular Photoinduced Electron Transfer Reactions of Micelle-Solubilized Substances
Authors: Suga Kosaku , Fujita Shigeru , Yamada Hiroshi , Fujihira Masamichi 
Published: July 2006

Abstract
The rate constants of intramolecular photoinduced electron-transfer reactions of a linked pyrene–viologen molecule A and a linked pyrene–ferrocene molecule B solubilized in micellar solutions of a hexadecyltrimethylammonium chloride were determined to be 9×108 and 4×108 s−1 respectively, from the stationary fluorescence intensity. However, the observed fluorescence decay curve of A suggests that a large fraction of the molecules have conformations for which the distances between two functional moieties are sufficiently small to permit direct electron transfer. The quasi-first-order rate constants of the intermolecular photoinduced electron-transfer reactions between 1-hexylpyrene (HPy) and dodecylviologen (DDV), and between HPy and butylferrocene (BFc) solubilized in a micellar solution, were also determined to be 9×106 and 2×107 s−1 respectively, from the fluorescence decay curves. It is shown that the rate constants of the intermolecular photoinduced electron-transfer reaction in micelles are determined by the diffusion of the reactants in a micelle. On the other hand, it is suggested that the rate constants of the intramolecular electron-transfer reactions are determined by the molecular conformations of the linked compounds in micelles.
Hydration of Oligosaccharides
Authors: Uedaira Hisashi , Ishimura Miyuki , Tsuda Sakae , Uedaira Hatsuho 
Published: July 2006

Abstract
The spin-lattice relaxation times, T1, of H217O have been measured for aqueous solutions of 2 di-, 2 trisaccharides, α-, and γ-c clodextrins as a function of the concentration at 25°C. The dynamic hydration numbers, nDHN, for 17 sugars including monosaccharides were expressed by the linear relation of the mean number of the equatorial OH groups. The second virial coefficients showed a good correlation with nDHN. Though the rotational correlation times, τch, of water molecules in the cosphere of sugar molecules increased with increasing the number of equatorial OH groups for monosaccharides, those for trisaccharides and cyclodextrins showed almost constant values. The relation between the values of the limiting diffusion coefficients and nDHN for sugars was found to be expressed by two lines with a large negative slope for mono- and di- saccharides, and a small negative slope for trisaccharides and cyclodextrins.
Synthesis and Chromogenic Properties of Some Water-Soluble 5-Nitro-2-Pyridylhydrazones
Authors: Kohata Katsunori , Kawamonzen Yoshiaki , Odashima Tsugikatsu , Ishii Hajime 
Published: July 2006

Abstract
Four new water-soluble hydrazones, α-(5-nitro-2-pyridyl)hydrazono-α-(2-quinolyl)-3-toluenesulfonic acid, α-(5-nitro-2-pyridyl)hydrazono-α-(2-thiazolyl)-3-toluenesulfonic acid, α-(2-benzothiazolyl)-α-(5-nitro-2-pyridyl)hydrazono-3-toluenesulfonic acid, and α-(2-benzimidazolyl)-α-(5-nitro-2-pyridyl)hydrazono-3-toluenesulfonic acid, were synthesized. Their proton dissociation constants were determined spectrophotometrically. The chromogenic properties of the synthesized hydrazones and their reactions with metal ions were investigated spectrophotometrically in detail. The results revealed that the synthesized hydrazones react with various metal ions including transition metal ions, especially with cadmium(II), nickel(II), and zinc(II) to form stable colored complexes with very large apparent molar absorptivities, so that they were found to be all very useful as highly sensitive spectrophotometric reagents.
The Solubility and Cyclodextrin Complexations of Fluorene, Fluoranthene, and Pyrene in Aqueous Medium
Authors: Wu Yue , Ishibashi Kazunari , Deguchi Toshio , Sanemasa Isao 
Published: July 2006

Abstract
The vapor saturation method was applied to prepare aqueous solutions saturated with a volatile solid solute such as fluorene, fluoranthene, or pyrene. Henry’s law was found to hold for their aqueous solubility, and sublimation enthalpy was evaluated for each solid solute. Complex formation constants with cyclodextrins at 25°C have been determined by the vapor saturation method. The applicability and limitation of the method are discussed.
The Anion Radicals of Pheophytin a and its Derivatives Studied by Means of CIDNP Technique
Authors: Maruyama Kazuhiro , Yamada Hiroko , Osuka Atsuhiro 
Published: July 2006

Abstract
We applied the Chemically Induced Dynamic Nuclear Polarization (CIDNP) technique to the photochemical reaction of pheophytin a (P1) and 4-methoxyphenol (1) in benzene-d6. The observed CIDNP effects were explained in terms of reversible electron-transfer reactions from 1 to 3(P1)* and from (P1)\ewdot to (1)\underset.+. The polarized signals of P1 were induced from the in-cage recombination of the triplet radical ion pair.
Excimer Fluorescence of Pyrene in Sol–Gel Silica
Authors: Matsui Kazunori , Usuki Naomi 
Published: July 2006

Abstract
The fluorescence and excitation spectra of pyrene at high concentrations were studied along the sol to xerogel stages of the sol–gel silica formed by the acidic hydrolysis of tetraethyl orthosilicate. The monomer and excimer fluorescence of pyrene were observed in the reaction system. Their relative intensities revealed that complex changes occurred that depended on the reaction time and the excitation wavelengths. The environmental polarity of the probe molecules also changed as shown by the fluorescence vibronic structure. The excitation spectrum of the excimer fluorescence in some stages was red shifted in comparison with that of the monomer fluorescence, indicating the existence of bimolecular ground-state pyrene associations. The mechanism by which pyrene molecules are trapped in the silica network is discussed on the basis of the results.
Tentative Reaction Network for Bromate–Bromide–Ferroin System and Simulation of Behavior of the System under Batch Reactor and Continuous-Flow Stirred Tank Reactor Conditions
Authors: Sasaki Yoshihiro 
Published: July 2006

Abstract
One tentative reaction network for the bromate–bromide–tris(1,10-phenanthroline)iron(II) (ferroin) system in an acidic medium was examined by means of a simulation method, which involved the Field–Körös–Noyes scheme, the reduction of HBrO2 and HOBr by ferroin via two-electron transfer processes and the reactions of Fe(phen)22+ with BrO3−, HBrO2, HOBr, and BrO2·. The network successfully reproduced the behavior of the system in a batch reactor. The behavior of the system in a continuous-flow stirred tank reactor (CSTR) was simulated under two CSTR conditions: 1) Bromide flowed into the CSTR, and 2) bromide did not flow into the CSTR. Under the former condition, the system exhibited bistability and sustained oscillations. The calculated oscillations were of small amplitude and high frequency. Under the latter condition, the system exhibited bistability.