bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protection of Phosphonate Function by Means of Ethoxycarbonyl Group. A New Method for Generation of Reactive Silyl Phosphite Intermediates
Authors: Sekine Mitsuo , Mori Hiroyuki , Hata Tsujiaki 
Published: July 2006

Abstract
Nucleoside ethoxycarbonylphosphonates were prepared by condensation of appropriately protected nucleosides with ethoxycarbonylphosphonic acid. They were easily converted by treatment with 1 M NaOH followed by trimethylsilylation to highly reactive bis(trimethylsilyl) nucleoside phosphite intermediates which were allowed in situ to react with water, diphenyl disulfide, 2,2′-dipyridyl disulfide, and aldehydes to afford the corresponding nucleoside phosphonates, nucleoside S-phenyl phosphorothioates, nucleoside phosphates, and nucleoside α-hydroxy phosphonates in good yields, respectively. The nucleoside phosphonates were further converted to nucleosides under mild acidic conditions. Thus, the ethoxycarbonyl group proved to serve as a versatile protecting group for not only H–P(O) but also HO–P(O) and hydroxyl groups of sugars.
Structure of Rishitinone, a Valencane Stress Metabolite in Diseased Potato
Authors: Katsui Nobukatsu , Yagihashi Fujio , Murai Akio , Masamune Tadashi 
Published: July 2006

Abstract
The isolation and structure elucidation of the title valencane sesquiterpene, a stress metabolite produced in diseased potato tubers, are described.
Substituent Effects on the Mesophase Stability for Cholesteryl Benzoylbenzoates
Authors: Koden Mitsuhiro , Takenaka Shunsuke , Kusabayashi Shigekazu 
Published: July 2006

Abstract
The thermal properties of cholesteryl esters of substituted benzoylbenzoic acids were examined. The substituent effects on the thermal stability of the chloesteric phase of these esters are quite striking. For cholesteryl 4-(4′-substituted benzoyl)benzoates, the Ch-I transition temperatures are slightly influenced by an electronic effect of the substituents, because the bond direction of the substituents is tilted with respect to the long molecular axis. For cholesteryl 4-(3′-substituted benzoyl)benzoates and cholesteryl 3-(4′-substituted benzoyl)benzoates, the Ch-I transition temperatures are influenced by the polarizability anisotropy of the terminal phenyl ring, which probably gives rise to a change in the ratio of the number of more-linear isomers to the number of less-linear isomers. For cholesteryl 4-(2′-substituted benzoyl)benzoates, the substituents increase the angle between the two phenyl rings, i.e., the thickness of the benzophenone moiety, due to the repulsive interaction between the substituent(s) and ortho-hydrogens of the other phenyl ring, and therefore decrease the Ch-I transition temperature largely.
The Synthesis of Racemic Fomannoxin, Anodendroic Acid, and 5-Acetyl-2-[1-(hydroxymethyl)vinyl]-2,3-dihydrobenzofuran
Authors: Yamaguchi Seiji , Kondo Seizo , Shimokawa Keiko , Inoue Osamu , Sannomiya Michiko , Kawase Yoshiyuki 
Published: July 2006

Abstract
2-Isopropenyl-2,3-dihydrobenzofuran was effectively prepared by two new methods. Fomannoxin and 5-acetyl-2-[1-(hydroxymethyl)vinyl]-2,3-dihydrobenzofuran were synthesized from 2-isopropenyl-2,3-dihydrobenzofuran, while anodendroic acid was synthesized from 2-(1-hydroxy-1-methylethyl)-2,3-dihydrobenzofuran.
Multidentate Ligand Kinetics. IV. Computer Simulation of the Steady State of the Free Ligands in a Coordination Chain Reaction
Authors: Katsuyama Tetsuo , Kumai Toshihiko 
Published: July 2006

Abstract
The ligand-substitution reactions between two multidentate ligand complexes in the presence of free ligands proceed by means of a coordination chain-reaction mechanism. The reaction was simulated on a computer under various conditions. The character of the steady state of the free ligands in the coordination chain reaction was discussed. The conditions under which the coordination chain reaction proceeds with the steady state of the free ligands were determined. The diagrams of the time development of the free ligands were found to be useful for studies using the coordination chain reaction.
A Kinetic Study of the Interaction of Sodium Dodecyl Sulfate with Bovine Serum Albumin by Means of a Pressure-jump Method
Authors: Takeda Kunio 
Published: July 2006

Abstract
A single relaxation was found in the system of sodium dodecyl sulfate and bovine serum albumin using a pressure-jump method with conductivity detection. The relaxation was observed in the concentration range of the surfactant below the critical micelle concentration. The relaxation time becomes fast with the stepwise formation of a complex between them and finally attains values compatible with those in the system of the pure surfactant micelle. This suggests a correlation of the relaxation phenomena with the partial breakdown and reformation of the complex. The similarity of the complex to the surfactant micelle was discussed on the basis of the kinetic aspects of the interaction of the surfactant with the protein.
Organofluorosilicates in Organic Synthesis. XVI. Synthesis of Organopentafluorosilicates via the Diels-Alder, Ene, and Friedel-Crafts Reaction. Their Transformations to Organic Halides and Alcohols
Authors: Tamao Kohei , Yoshida Jun-ichi , Akita Munetaka , Sugihara Yoshihiro , Iwahara Takahisa , Kumada Makoto 
Published: July 2006

Abstract
Described herein are several representative examples of cleavage reactions of otherwise hardly accessible organopentafluorosilicates which are obtainable via the Diels-Alder reaction, ene reaction, and the Friedel-Crafts reaction of vinyl-, ethynyl-, or allyl-trichlorosilanes. The Diels-Alder reaction between vinyltrichlorosilane and o-xylylene generated in situ by debromination of α,α′-dibromo-o-xylene afforded (1,2,3,4-tetrahydro-2-naphthyl)trichlorosilane which was converted to the corresponding silicate. The silicate reacted with NBS and MCPBA to give the respective bromide and alcohol. The Diels-Alder reaction between ethynyltrichlorosilane and methyl coumalate gave a mixture of meta and para isomers of methyl (trichlorosilyl)benzoate in the ratio of 55/45, the silicate of which reacted with NBS to give two positional isomers of methyl bromobenzoate. The electronic effect of the methoxycarbonyl group on the Si–C bond cleavage was small. The silicate derived from 4-octenyltrichlorosilane which was obtained by the ene reaction between vinyltrichlorosilane and 1-hexene afforded, upon treatment with NBS, 4-octenyl bromide in the ratio of E⁄Z=83⁄17. The sterically crowded neophylsilicate obtainable via the Friedel-Crafts reaction of 2-methyl-1-propenyltrichlorosilane with benzene underwent the cleavage reaction with NBS in methanol. Neophyl bromide was formed with CuBr2 in a low yield, no product being formed arising from rearrangement of the neophyl radical.
Tris(2,2′-bipyridine)ruthenium(II)-photosensitized Reductions of Methyl Viologen and Molecular Oxygen in a Network of Water-swollen Cation-exchange Resin
Authors: Kurimura Yoshimi , Katsumata Kimiyo 
Published: July 2006

Abstract
The visible-light-induced reduction of methyl viologen was found to occur in water-swollen cation-exchange resin, which adsorbed both Ru(bpy)32+ and methyl viologen (RMCA resin) with the aid of triethanolamine (TEA) as a donor. With illumination, the generation of hydrogen peroxide proceeds in an oxygenated TEA solution containing RMCA resin. Hydrogen peroxide is produced via the superoxide ion, which is itself formed by the reaction of the methyl viologen radical in the resin with the oxygen molecule in the bulk of the solution. The Ru(bpy)32+-photosensitized reaction processes leading to the generation of methyl viologen radical and hydrogen peroxide in the heterogeneous systems are discussed on the basis of the results obtained.
Direct Measurement of the Interaction Energy between Solids and Gases. VIII. A High-temperature Calorimeter for the Determination of Heats of Adsorption from Room Temperature to 700 K
Authors: Tsutsumi Kazuo , Hagiwara Seiichi , Mitani Yoshio , Takahashi Horoshi 
Published: July 2006

Abstract
A high-temperature calorimeter of the twin conduction type was designed with the capability of measuring heats of adsorption of gases on solids in the temperature range RT to 700 K. A chromel-alumel thermopile was used as the detector and a volumetric adsorption apparatus was equipped. Its calibration and preliminary experiments on heats of adsorption of ammonia on zeolites are described.
Reactions of Chloroiron(III) Schiff Base Complexes with Superoxide Ion in Dimethyl Sulfoxide
Authors: Matsushita Takayuki , Kono Hiroshi , Nishino Mitsuru , Shono Toshiyuki 
Published: July 2006

Abstract
A series of monomeric chloroiron(III) complexes with the quadridentate or quinquedentate Schiff bases such as N,N′-disalicylideneethylenediamine or bis[3-(salicylideneamino)propyl]amine react with superoxide ions, O2−, in dimethyl sulfoxide to give the corresponding μ-oxo dimers. The polymeric chloroiron(III) complexes with the polymeric (oligomeric) Schiff bases derived from 5,5′-methylenedisalicylaldehyde and triamines react with O2− in dimethyl sulfoxide to give the oxygenated complexes, probably dioxygen adducts, FeIII–O2−. This is suggested by the absorption spectra and the polarographic measurements.
The Temperature Dependence of the Peak Height of the Lead Ion in Square-wave Polarography
Authors: Hatanaka Nobuko 
Published: July 2006

Abstract
The peak height of the square-wave (s.w.) polarogram of lead increased markedly upon the addition of anions forming insoluble compounds with lead, and the temperature coefficient of the peak height showed a negative value, different from the theoretical value in a diffusion-controlled or an electrode-reaction-rate-controlled process at the following concentrations of anions; [Cl−]=1 M, [Br−]=10−2 M, [SCN−]=10−1 M for 10−4 M lead. In the case of the addition of iodide, the s.w. peak height of lead increased at concentrations of iodide above 10−4 M for 10−4 M lead but the temperature coefficient of the peak height was always positive. Moreover, another peak due to lead appeared superimposed on the oxidation peak of iodide at a more positive potential, and this peak had a negative temperature coefficient. It was found that these phenomena were attributable to a specific adsorption of lead on mercury electrodes, induced by the foremost adsorbed anions. However in the case of the addition of iodide or in that of a high concentration of bromide or thiocyanate, the reversibility of the electrode process decreased and the temperature coefficient varied to a positive value in spite of the increase in adsorbed depolarizers.
Configuration of Alanine Part in Natural Octopine
Authors: Goto Kazuo , Waki Michinori , Mitsuyasu Nobuo , Kitajima Yasuo , Izumiya Nobuo 
Published: July 2006

Abstract
Octopine has a structure of N2-(1-carboxyethyl)arginine or N-(1-carboxy-4-guanidinobutyl)alanine. Configuration of the arginine part in natural octopine is determined as (S), whereas that of the alanine part has been assumed as (R). The configuration of the alanine part was concluded to be (R) by the present synthesis of (+)-octopine, which was identical with the natural one, by a sequence of reactions starting from (R)-alanine and (R)-2-bromo-5-acetamidopentanoic acid. The reaction of (R)-alanine and (R)-2-bromo-5-acetamidopentanoic acid in alkaline conditions gave N2-((R)-1-carboxyethyl)-N5-acetyl-(S)-ornithine which was converted to N2-((R)-1-carboxyethyl)-(S)-ornithine ((R),(S)-octopinic acid) by hydrolysis with hydrochloric acid. (R),(S)-Octopinic acid gave (+)-octopine ((R),(S)-octopine) by guanidination. The reaction of (S)-alanine and (R)-2-bromo-5-acetamidopentanoic acid led to give (S),(S)-octopinic acid and subsequently (+)-isooctopine ((S),(S)-octopine).
Sorption Behavior of Aromatic Compounds in Water on β-Cyclodextrin Polyurethane Resins
Authors: Kawaguchi Yoshihiro , Mizobuchi Yoshikazu , Tanaka Minoru , Shono Toshiyuki 
Published: July 2006

Abstract
The sorption behavior of aromatic compounds in water on β-cyclodextrin polyurethane resins was evaluated by batch and column procedures. The values of their sorption capacities obtained in the batch experiments were comparable to those of Amberlite XAD-2 and/or -7. In the column experiments, β-H6XDI-P-6.0-M showed a quantitative collection of the aromatic compounds at low concentrations, while Amberlite XAD-7 did not.
The Conversion of Methanol into Hydrocarbons over Metal Salts of Heteropolyacids
Authors: Baba Toshihide , Sakai Junya , Ono Yoshio 
Published: July 2006

Abstract
Metal salts of heteropolyacids are active catalysts for the conversion of methanol into hydrocarbons. Though the activity depends on the kind of metal salt, the reaction mechanism for the conversion is common to most of the metal salts, and the active centers are probably Brönsted acid centers.
Efficient Photoreduction of Methylviologen Sensitized by Chlorophyll Derivatives and Hydrogen Evolution by Visible Light
Authors: Koiso Takashi , Okuyama Masataka , Sakata Tadayoshi , Kawai Tomoji 
Published: July 2006

Abstract
The photoreduction of methylviologen sensitized by chlorophyll derivatives and porphines was investigated using EDTA as a reducing agent. The quantum yield of the photoreduction depends greatly on the kind of central metal ion of chlorophyll derivatives and porphines. Zn–chlorophyll-a and Zn–tetraphyenylporphine show a high quantum efficiency amounting 0.4, which is higher than that of chlorophyll-a.
A Theoretical Study of the Resonance Raman Scattering from a Molecular System. Effects of Vibronic and Nonadiabatic Couplings
Authors: Seo Katsumi , Kono Hirohiko , Fujimura Yuichi 
Published: July 2006

Abstract
A theory of the resonance Raman scattering (RRS) from a molecular system in which the vibronic levels of the resonance state are perturbed by both the Herzberg-Teller vibronic and the nonadiabatic coupling is developed. By using the time-independent Green-function formalism, an expression for the RRS is derived in the three-electronic-state model. The RRS cross-sections obtained are classified into four types: the pure RRS cross-section, independent of the coupling mode: the vibronically induced one, the nonadiabatically induced one, and the interference term. Assuming that the molecular system consists of a totally symmetric mode characterized by a displaced harmonic oscillator, with a nontotally symmetric mode as the inducing mode, analytical expressions for the relevant RRS cross-sections of the ns-th order vibrational transition for the totally symmetric mode are derived. Model calculations of the cross-sections indicate that, for an increasing potential displacement parameter, Δ, between the coupled states, the nonadiabatic correction to the higher-order vibrational transitions, as well as the zero-order vibrational transition, makes a significant contribution.
Reactions of Polymeric Chloromanganese(III) Schiff Base Complexes with Superoxide Ion in Dimethyl Sulfoxide
Authors: Matsushita Takayuki , Nishino Mitsuru , Shono Toshiyuki 
Published: July 2006

Abstract
The polymeric Mn(III) Schiff base complexes react with superoxide ions (O2−) in dimethyl sulfoxide (DMSO) to give the oxygenated complexes, while the corresponding monomeric Mn(III) complexes are reduced with O2− to the Mn(II) complexes.
Syntheses and Configurations of Copper(II) and Nickel(II) Complexes of trans-1,2-Dicyano-1,2-cyclohexanediamine
Authors: Okawa Hisashi , Kakimoto Miyuki , Izumitani Tatsuo , Kida Sigeo 
Published: July 2006

Abstract
Complexation of the solid and oily isomers of 1,2-dicyano-1,2-cyclohexanediamine (abbreviated as s-cychd and o-cychd respectively) with nickel(II) and copper(II) ions have been investigated. Only s-cychd formed the complexes Ni(s-cychd)2Cl2 and Cu(s-cychd)2X2 (X=Cl, Br, NO3, ClO4). Based on the configuration of the nickel complex, s-cychd was shown to be the (E)-isomer and thence o-cychd the (Z)-isomer. Configurations of the copper complexes have been dicussed on the basis of electronic spectra of DMF solution and of powder sample.
Photoredox Chemistry of Copper(II) Perchlorate in Methanolic Medium
Authors: Silva Paulo Augustro Correa da , David Pazhayirayyathu Geeverghese 
Published: July 2006

Abstract
Ultraviolet irradiation of copper(II) perchlorate in methanol yields copper(I) and formaldehyde as the products. The primary photoprocess is believed to be the homolytic cleavage of copper(II)-methanol bond. Secondary reactions of oxidized solvent species with copper(II), copper(I), and solvent molecules affect the product quantum yields. Variation of the quantum yield for copper(I) as a function of irradiating wavelength indicates the existence of methanol-to-copper(II) charge transfer band in the 200–250 nm region.
The Thermal Decomposition of N,O-Diacyl-N-t-butylhydroxylamines. IV. A Novel Acyloxyl Migration in N,O-Diacyl-N-t-butylhydroxylamines
Authors: Uchida Yuzuru , Kozuka Seizi 
Published: July 2006

Abstract
Several N,O-diacyl-N-t-butylhydroxylamines were prepared, and their thermal decompositions were studied. N-Propionyl-O-benzoyl-N-t-butylhydroxylamine gave N-t-butyl-2-benzoyloxypropanamide, together with the decomposition products, N-t-butylpropanamide and benzoic acid, upon thermal decomposition in tetralin. Similar benzyloxyl migrations were found in the thermal decomposition of N-butyryl, N-valeryl, and N-(3-phenylpropionyl) derivatives.
Steric Effect on Carbon-13 Nuclear Magnetic Resonance Shifts in Poly(vinylnaphthalene)s
Authors: Seki Kazuhiko , Mori Shinji , Imamura Yoshio 
Published: July 2006

Abstract
From the point of view of the rotational isomeric state for the side groups (π- and o-conformation), the steric compression effect on the 13C chemical shift of the aliphatic carbons in poly(1-vinylnaphthalene)(P1VN) and poly(2-vinylnaphthalene)(P2VN) were evaluated according to H.J. Schneider’s method. In addition to the steric compression effect, the ring current effect by the naphthyl groups in P1VN and P2VN was taken into account. The numerical results suggested that the marked higher field shifts of the methine carbon of P1VN in comparison with that of P2VN, was attributed to the strong steric compression with the 1-naphthyl group (occupied the stable π-conformation) in the same monomer units. While in the P2VN chain, the resonances of the aliphatic carbons were calculated to be in the vicinity of those of polystyrene. Naphthyl ring current contribution to 13C-NMR chemical shifts was found to be small in comparison to the dominant steric compression effect.
Thermochemical Studies on 2,4,6-Triisopropylbenzophenone and Its Photo-isomer, 3′,5′-Diisopropyl-4,4-dimethyl-3-phenyl-1,2-benzocyclobuten-3-ol. Evaluation of Magnitude of Light Energy Stored in the Latter Molecule
Authors: Inagaki Sadayasu , Murata Shigeo , Sakiyama Minoru , Ito Yoshikatsu , Umehara Yasutoshi , Hijiya Toyoto , Matsuura Teruo 
Published: July 2006

Abstract
Standard energy of combustion and standard enthalpy of sublimation were determined for the title compounds with static bomb combustion calorimetry and with sublimation calorimetry, respectively. Derived standard enthalpies of combustion and of formation at 298.15 K were as follows: ΔH°c(c)=−(12354.3±1.8), ΔH°f(c)=−(304.6±3.4), and ΔH°f(g)=−(189±8) kJ mol−1, respectively, for 2,4,6-triisopropylbenzophenone(1), and ΔH°c(c)=−(12440.6±1.6), ΔH°f(c)=−(218.3±3.3), and ΔH°f(g)=−(101±10) kJ mol−1, respectively, for 3′,5′-diisopropyl-4,4-dimethyl-3-phenyl-1,2-benzocyclobuten-3-ol(2). The enthalpy change for the reaction: 1(g)→2(g), of 88 kJ mol−1, which may be supposed to be the magnitude of light energy stored in the latter molecule, has been discussed.
Specific Anion Effects on Water Structure at Polypeptide Monolayer–Water Interface
Authors: Shibata Akira , Yamashita Shinsuke , Yamashita Takuya 
Published: July 2006

Abstract
The specific anion effects on water structure at the polypeptide monolayer–water interface were investigated. It was found that the effects of anions on increasing the film transition pressure were in the order of SCN−&gt;Br−&gt;Cl−&gt;F− in line with that of those anions as breakers of water structure. The SCN− ion disrupts the hydrophobic hydration surrounding the hydrocarbon moieties of polypeptides and lipids at the interface. On the other hand, the presence of F− ion as a structure maker tends to stabilize the hydrophobic bonding. The increase of the film transition pressure on KSCN subsolution was associated with a difference in the conformation between poly(γ-benzyl l-glutamate) and poly(γ-benzyl Dl-glutamate). The infrared spectra of polymers obtained from single and mixed films were practically identical with the collapsed films in the presence and the absence of SCN− and F− ions.
Spectroscopic Properties for High-pressure Polymorphs of Calcium and Strontium Metasilicates
Authors: Machida Ken-ichi , Adachi Gin-ya , Shiokawa Jiro 
Published: July 2006

Abstract
The IR spectra for the high-pressure polymorphs of alkaline-earth metasilicates, viz. α-CaSiO3, δ-CaSiO3, α-SrSiO3, δ-SrSiO3, and δ′-SrSiO3, which consist of cyclic anions, (Si3O9)6− or (Si4O12)8− rings, were studied over a range of 1200–400 cm−1. These silicates gave absorption bands in wavenumbers of about 1050–820 cm−1, 750–620 cm−1, and below about 580 cm−1, based on symmetrical and anti-symmetrical stretches of Si–O bonds and Si–O bending modes for tetrahedral SiO4 units, and Ca–O or Sr–O stretches. Among them, the bands characteristic of the silicate anions with ring structure in the SrSiO3 polymorphs were found to shift to lower wavenumber with transformation into the δ′ form. This suggests that the (Si4O12)8− ring in δ′-SrSiO3 is less flexible than the (Si3O9)6− ring in the α or δ form. The experimental result that the quenching temperature of δ′-SrSiO3:Eu2+ phosphor is higher than that of the δ form supports this consideration.
Electroreduction of 4-(2-Thienyl)quinazoline in Acetonitrile
Authors: Devi T Priyamvada , Kalidas Chatty , Venkatachalam Chitoor Sivaramakrishnan 
Published: July 2006

Abstract
The electroreduction of 4-(2-thienyl)quinazoline (4-TQ) in acetonitrile solutions gave a single two-electron well-defined polarographic wave. The well-defined wave was found to be diffusion-controlled and irreversible on the basis of the usual criteria. Based on the controlled-potential electrolysis and cyclic voltammetric experiments, a disproportionation reaction mechanism is suggested for 4-TQ reduction in acetonitrile.
Synthesis of 4,7-Indolequinones by Photoinduced Reaction of Azidoquinones
Authors: Kozuka Tadashi 
Published: July 2006

Abstract
Various azidoquinones were prepared from methyl 3-substituted 2,3-dihydro-5-hydroxy-6-methylbenzofuran-2-carboxylate. Irradiation of these azidoquinones gave methyl 3-substituted 6-methyl-4,7-dioxoindole-2-carboxylates, a model of mitomycin analogs, in a moderate yield.
Syntheses and Properties of Copolymers of Isopropenyl-1,3,5-triazines and Methacrylic Esters
Authors: Seo Toshihiro , Kakurai Toshio 
Published: July 2006

Abstract
Copolymerizations of 2-amino-4-(substituted amino)-6-isopropenyl-1,3,5-triazines (methacryloguanamine) with alkyl methacrylates using redox initiator gave polymers with high molecular weights in satisfactory yields. The monomer reactivity ratios and Q-e values were also determined. Softening and glass transition temperatures rose and specific gravity increased with the increase in the content of triazine units. The copolymers were slightly soluble in nonpolar solvents and readily soluble in polar solvents with a solubility parameter (δ)=11–13. This polymer with aminotriazine groups showed high viscosity in acid solution and can be utillized as polyelectrolyte.
Studies on the Interaction between Mercury(II) Chloride and Copper(I) Halides in Solid State
Authors: Beg Mirza Aijaz , Ahmad Afaq 
Published: July 2006

Abstract
Kinetics and mechanism of HgCl2–CuI and HgCl2–CuBr reactions were studied in solid state. It has been demonstrated that HgCl2 reaches CuI by surface migration and the reaction proceeds through counter diffusion of Cu+ and Hg2+. Both the reactions follow the parabolic rate law and the activation energies are 77.11±3.84 and 51.08±1.29 kJ/mol. While the former is a complex multi-stage reaction, the latter is a simple exchange process.