bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Structural Analysis of 5-Deoxy-3-O-methyl-5-C-[(R)- and (S)-phenylphosphinothioyl]-α- and β-d-xylopyranoses
Authors: Hanaya Tadashi , Shigetoh Nobuyuki , Yamamoto Hiroshi 
Published: July 2006

Abstract
Treatment of 5-deoxy-5-iodo-1,2-O-isopropylidene-3-O-methyl-α-d-xylofuranose with ethyl phenylphosphinothioate in the presence of NaH in DMF gave a 1:1 mixture of the 5-deoxy-5-C-[(R)- and (S)-(ethoxy)phenylphosphinothioyl] derivatives. Reduction of these d-xylofuranoses with sodium dihydrobis(2-methoxyethoxy)aluminate, followed by the acid hydrolysis, provided the title compounds, which are the first sugar analogues having a phosphinothioyl group in the hemiacetal ring. These compounds were converted into four, separable 1,2,4-tri-O-acetates, the structures and conformations of which were established by spectroscopy. The corresponding per-O-acetyl-5-deoxy-5-C-[(R)- and (S)-phenylphosphinyl] analogues were also prepared and their previously presented structures were revised. Complete 1H NMR (500-MHz) parameters of these two types of compounds are given for a comparative, structural study.
Promoter Effect of Platinum on Liquid-Phase Dehydrogenation of 2-Propanol by a Nickel Fine-Particle Catalyst
Authors: Noda Michio , Shinoda Sumio , Saito Yasukazu 
Published: July 2006

Abstract
A platinum-deposited nickel fine-particle catalyst was shown to be more active than a nickel-alone catalyst. A study of the temperature dependence of a rate constant revealed that platinum increased the frequency factor of the rate constant. An experiment regarding poisoning showed that the number of active sites was the same for the two catalysts. Thus the promoter effect was ascribed to an increase in the frequency factor per active site.
The Crystal Structure of 1,5-Dithioniabicyclo[3.3.0]octane Bis(trifluoromethanesulfonate). The First Structural Characterization of Dithionia Dication and Strong S···O Interactions between Cations and Anions
Authors: Iwasaki Fujiko , Toyoda Nobuhiko , Akaishi Ryouichi , Fujihara Hisashi , Furukawat Naomichi 
Published: July 2006

Abstract
The crystal structure of 1,5-dithioniabicyclo[3.3.0]octane bis(trifluoromethanesulfonate) has been determined by the X-ray method to elucidate the structure of a dithionia dication. Crystal data; C6S2H122+·2CF3SO3−, Fw=446.43, orthorhombic, Pccb, a=16.775(2), b=9.893(3), c=19.592(3) Å, V=3251(1) Å3, Z=8, Dx=1.825 Mg m−3. There are two independent dications, A and B, in the crystals, each of which has a crystallographic twofold axis. The mean S+–S+ distance is 2.124 Å. The conformation of the eight-membered ring is a distorted chair–chair form. Very strong interactions were observed between S+ of dications and O atoms of counter anions. The average distance of S+···O is 2.724 Å and colinear arrangements of O···S–S···O are formed with the central twofold axis. Other weak S···O interactions (2.903–3.153 Å) were also observed between dications and anions. The coordination around S is a roughly distorted octahedron with two C and two O atoms in a plane and apical S and O atoms.
Rotational Lattice Vibrations of Tetramethyl- and Tetramethyl-d12-pyrazine Crystals
Authors: Maehara Masayoshi , Hieida Toshikazu , Nibu Yoshinori , Shimada Hiroko , Shimada Ryoichi 
Published: July 2006

Abstract
The low-frequency Raman bands of the tetramethyl- and tetramethyl-d12-pyrazine crystals and their hydra ted crystals were studied at various temperatures between 4.2 and 298 K. The isotopic factors and the temperature effects on the frequencies of the Raman bands indicate that the low-frequency Raman bands observed in the crystal are to be ascribed to the rotational lattice vibrations. A smooth curve of the plot of the Raman frequency versus temperature suggests that no apparent temperature-induced phase transition takes place in the tetramethylpyrazine crystal. Classification of the rotational lattice vibrations into symmetry species was made based on the polarization behavior of the Raman bands. It was also observed that tetramethylpyrazine hydrates quite easily with a trace of moisture in the air.
A Conductance Study of 1:1 Complexes of 15-Crown-5, 16-Crown-5, and Benzo-15-crown-5 with Alkali Metal Ions in Nonaqueous Solvents
Authors: Takeda Yasuyuki , Katsuta Koji , Inoue Yoshihisa , Hakushi Tadao 
Published: July 2006

Abstract
Conductivities of alkali metal salts in the presence of 15-crown-5 (15C5), 16-crown-5 (16C5), and benzo-15-crown-5 (B15C5) were measured at 25 °C in acetonitrile, propylene carbonate, and methanol. Formation constants (KML+) of 1:1 complexes of 15C5 and 16C5 with alkali metal ions and conductance parameters (λ0 and å) of the Na+ complexes of 15C5, 16C5, and B15C5 were determined, λ0 and å being limiting ionic molar conductivity and distance of closest approach of ions, respectively. In general, selectivities of 15C5 and 16C5 for alkali metal ions show the size-fit correlation. In contrast to 15C5, 16C5 forms much the most stable complex with Na+ in every solvent. Generally, KML+-value sequences of a given crown ether complex for the solvents are the reverse of donor-number sequences of the solvents. Value of å increases with an increase in the cationic size (Na+→Na(15C5)+→Na(16C5)+→Na(B15C5)+). Mobility of the Na+–crown ether complex decreases with an increase in the size of the crown ether. From λ0 values and Walden products of these Na(crown ether)+ complexes and a tetrapropylammonium ion, it seems likely that Na(15C5)+ and Na(16C5)+ act as structure breakers in hydrogen-bonding solvents, whereas Na(B15C5)+ as a structure maker.
Stabilities and Transfer Activity Coefficients of Benzo-15-crown-5-Alkali Metal Ion Complexes in Various Solvents
Authors: Takeda Yasuyuki , Kumazawa Toshihiro 
Published: July 2006

Abstract
Stability constants in acetonitrile and methanol of 1:1 benzo-15-crown-5 (B15C5)–alkali metal ion complexes and the solubility of B15C5 in acetonitrile, propylene carbonate, methanol, and water were determined at 25 °C by conductometry and spectrophotometry, respectively. In general, selectivity tendency of B15C5 for the alkali metal ions except for Li+ can be interpreted in terms of size-relationship. Stability sequences of the B15C5–alkali metal ion complex among the solvents, except for Rb+ and Cs+ complexes, are the reverse of solvation-ability sequences of the solvents to the corresponding alkali metal ion. By using the stability constants of the B15C5–alkali metal ion complexes, transfer activity coefficients (γ) of the B15C5 complexes were then calculated from γ values of B15C5 (obtained from solubilities of B15C5) and those of alkali metal ions. The γ value of the B15C5 complex from methanol to acetonitrile and propylene carbonate generally varies with a variety of alkali metal ions. From γ values of the B15C5 complexes, it is concluded that there exists a possible specific interaction between the alkali metal ion held in the B15C5 cavity and solvent molecules when the alkali metal ion is much smaller or larger than the B15C5 cavity.
Application of Hydrogen Ion Sensitive Field Effect Transistor to the Kinetic Study of Fast Reaction in Solution
Authors: Nakatsuka Thoru , Nakamura Michihiro , Sano Takayuki 
Published: July 2006

Abstract
The ion sensitive field effect transistor(ISFET) developed for pH measurement was incorporated with the stopped flow apparatus for direct detection of the fast change in the hydrogen ion concentration. By the experiments on the dehydration reaction of carbonic acid, it was proved that the pH sensor has a fast response time (&lt;2 ms) beyond the resolution time of stopped flow apparatus, and the constructed apparatus can be satisfactorily applied to the fast reaction kinetics with the sensitivity for the pH change more than 0.01 pH unit.
57Fe-Moessbauer and 13C-CP-MAS NMR Spectroscopic Studies of the Reaction Products of Ruthenocene Derivatives with Lewis Acids
Authors: Watanabe Masanobu , Masuda Yuichi , Motoyama Izumi , Sano Hirotoshi 
Published: July 2006

Abstract
Adducts of ruthenocene with Lewis acids, such as HgCl2, SnCl4, and I2, are studied mainly by means of high resolution solid state 13C NMR spectroscopy and 57Fe-Moessbauer spectroscopy. The large low-field shifts found in the 13C-CP-MAS NMR spectroscopy suggest the presence of a direct chemical bond between the ruthenium and the Lewis acids. Ferrocenylruthenocene and biruthenocene give stable adducts with HgCl2 and I2. 57Fe-Moessbauer and 13C-CP-MAS NMR spectroscopic studies suggest the presence of a chemical bond, such as Ru–Hg, Ru–I, in the adducts.
Effects of Methyl Substituent on Solvent Extraction of Copper(II) with o-, m-, and p-Methylbenzoic Acids
Authors: Yamada Hiromichi , Horikawa Shiho , Fujii Yukio , Mizuta Masateru 
Published: July 2006

Abstract
The extraction of copper(II) with o-, m-, and p-methylbenzoic acids in 1-octanol was carried out at 25 °C and aqueous ionic strength of 0.1 mol dm−3 (NaClO4). In contrast to the extraction with benzoic acid, in which only the monomeric copper(II) benzoate is extracted, the dimeric copper(II) species is also responsible for the extraction of copper(II) with o- and m-methylbenzoic acids in 1-octanol together with the monomeric one. On the other hand, p-methylbenzoic acid has a poorer extracting capability than o- and m-methylbenzoic acids and only the monomeric copper(II) species is responsible for the extraction.
Raman Spectral Characteristics of Bis(terdentate)cobalt(III) Complexes with N and O Donor Atoms
Authors: Kawamoto Tatsuya , Yasui Takaji , Einaga Hisahiko , Hidaka Jinsai 
Published: July 2006

Abstract
The Raman spectra were measured for the bis and mixed type cobalt(III) complexes with ethylenediamine-N-acetate (edma) in an aqueous solution in the skeletal vibration region. The Raman bands could be classified into five vibration modes; a totally symmetric stretching vibration mode in the 510–650 cm−1 region, a stretching vibration mode excluding the totally symmetric one in the 410–540 cm−1 region, a skeletal breathing vibration mode in the 370–490 cm−1 region, a skeletal bending deformation mode in the 270–420 cm−1 region, and a chelate ring deformation mode in the 220–270 cm−1 region. Differences in the skeletal vibrations were observed between the fac and mer isomers for the chelate ring arrangement. Further, differences for the chelate ring arrangement between the Raman spectra of sym-fac and unsym-fac isomers were observed in the skeletal bending deformation mode. The cobalt(III) complexes with the terdentate ligands containing N-methyl group exhibited Raman bands shifted to a lower frequency than those of the corresponding cobalt(III) complexes containing no N-methyl group in the totally symmetric stretching vibration mode region.
Phase-Transfer-Catalyzed Azo Coupling Reactions in Two-Phase Systems
Authors: Hashida Yoji , Kubota Kazuhiro , Sekiguchi Shizen 
Published: July 2006

Abstract
The azo coupling reaction of p-methoxybenzenediazonium tetrafluoroborate with N,N-dimethylaniline has been investigated in a water-1,2-dichloroethane system. It has been found that, among the several additives examined, the phenolate ion, generated from picric acid or 2,4-dinitro-1-naphthol, acted as an effective phase-transfer catalyst. Further, the reaction of p-diethylaminobenzenediazonium tetrafluoroborate with dimedone, an active methylene compound, has also been investigated in the same two-phase system; a remarkable acceleration in the rate was observed in the presence of tetraalkyl onium salts, and even in their absence.
Studies on Chitin. 14. N-Acetylation Behavior of Chitosan with Acetyl Chloride and Acetic Anhydride in a Highly Swelled State
Authors: Kurita Keisuke , Chikaoka Satoyuki , Kamiya Mami , Koyama Yoshiyuki 
Published: July 2006

Abstract
N-Acetylation on chitosan has been studied in a highly swelled state with acetyl chloride in comparison with that with acetic anhydride under various conditions to establish the general possibility and scope of the acylation reactions on chitosan and other polysaccharides. A highly swelled chitosan precipitate prepared by pouring a chitosan solution in aqueous acetic acid/methanol into pyridine is quite suitable for efficient modifications, and the reaction with either acylating reagent proceeded smoothly and reproducibly under mild conditions. Although acetic anhydride is generally more appropriate in protic solvens, acetyl chloride is effective and advantageous especially in pyridine containing only small amounts of protic solvents.
Solvation Structure of Copper(II) Ion in N,N-Dimethylformamide and N,N-Dimethylformamide–Acetonitrile Mixtures Determined by the X-Ray Diffraction Method
Authors: Ozutsumi Kazuhiko , Ishiguro Shin-ichi , Ohtaki Hitoshi 
Published: July 2006

Abstract
The solvation structure of copper(II) ion in N,N-dimethylformamide (DMF) and N,N-dimethylformamide–acetonitrile (AN) mixtures has been investigated by means of X-ray diffraction at 25 °C. The X-ray scattering data for the copper(II) perchlorate DMF solution were well-interpreted in terms of the presence of the axially elongated octahedral [Cu(dmf)6]2+ ion in DMF. Among the six DMF molecules, four of them are at the distance of 203(3) pm at the equatorial position and the other two are at 243(5) pm at the axial one. On the other hand, in copper(II) perchlorate DMF–AN solutions with the Cdmf⁄CCu mole ratios of 5.308 and 7.435, where Ci denotes the total concentrations of species i, the copper(II) ion is coordinated with four DMF molecules within the square-plane and with no solvent molecule along the axis of the plane. The equatorial Cu–O bond length is 200(1) pm and practically the same as that within the [Cu(dmf)6]2+ ion in DMF. In copper(II) nitrate DMF solutions (1.086 and 1.500 mol dm−3), a nitrate ion binds to copper(II) ion at the equatoral position and the distorted octahedral [CuNO3(dmf)5]+ complex is formed.
Alumina-Anchored Cobalt Porphine Catalysts for the Conversion of Quadricyclane to Norbornadiene
Authors: Miki Sadao , Asako Yoshinobu , Morimoto Masayoshi , Ohno Toshinobu , Yoshida Zen-ichi , Maruyama Toshiro , Fukuoka Masahiro , Takada Tomoaki 
Published: July 2006

Abstract
Methods are described for the preparation of cobalt(II) deuteroporphyrin and cobalt(II) tetrakis(p-sulfonatophenyl)porphine anchored on alumina beads coated with polyaminesulfone-A. Wavelength dispersive X-ray microanalysis showed that the cobalt(II) porphine distributes within the catalyst outer surface layer of ca. 100 μm depth. The catalysts are highly active for the cycloreversion of quadricyclane to norbornadiene. A detailed kinetics of the isomerization using an isothermal recycle reactor gave a rate expression of Langmuir–Hinshelwood type. The catalysts gradually lose their activity, which can be regenerated completely by heating the catalysts at 200 °C in vacuo.
The Crystal Structure of the Gold(III) Complex, Tribromo(dibenzyl sulfide)gold(III)
Authors: Takahashi Kazuhiro , Kato Katsuo 
Published: July 2006

Abstract
The crystal structure of tribromo(dibenzyl sulfide) gold(III) has been determined. The crystal belongs to the triclinic system, with a=7.002(1), b=7.949(1), c=17.244(2) Å, α=88.83(1), β=79.52(1), and γ=66.35(1)°, with the space group P\bar1 and with Z=2. The complex has a square-planar coordination geometry with 3BrlS donor atoms. The bond lengths of the three Au–Br coordinations are in the range of 2.41–2.43 Å.
Active and Selective Transports of Alkali Metal Ions through Hydrophobic Membrane
Authors: Hayashita Takashi , Tedo Kiyotaka , Yamabe Takeo , Igawa Manabu 
Published: July 2006

Abstract
The active and selective transport of alkali metal ions coupled with proton permeation, were observed through a dense hydrophobic membrane. The flux of alkali metal ions increased with the decrease in the degree of hydration. The behavior can be comprehended in terms of the asymmetrical permeabilities of ions through the hydrophobic membrane.
Inclusion Properties of Acyclic p-Substituted Phenol–Formaldehyde Oligomers
Authors: Sone Tyo , Ohba Yoshihiro , Yamazaki Hajime 
Published: July 2006

Abstract
Acyclic para-substituted phenol–formaldehyde oligomers (R=H, Me, n-Bu, t-Bu, and cyclohexyl; the number of phenol units=3–6) form host–guest complexes with various organic compounds. The inclusion property of the acyclic oligomers is greatly influenced by the p-substituents of phenol and the number of phenol units in the oligomers; for example, a) while the t-butyl tetramer is effective, the corresponding butyl tetramer has a poor ability for the complex formation, and b) the tetramers and pentamers are good hosts for organic compounds, forming 2:1 (host:guest) complexes in many cases.
Sequential Reactions of Michael Addition and Peterson Condensation of 1-Silylvinyl Ketones with Grignard Reagents: Study of Stereoselectivity
Authors: Tanaka Junji , Kobayashi Hiroshi , Kanemasa Shuji , Tsuge Otohiko 
Published: July 2006

Abstract
1-Silylvinyl ketones undergo smooth Michael addition with Grignard reagents generating magnesium enolates which are then trapped with benzaldehyde to give E- and Z-isomers of enones after Peterson condensation. (E)-Olefins become major products under a thermodynamic control when the condensation with benzaldehyde is carried out at room temperature in diethyl ether, while Z-isomers are more favored as kinetically controlled products at −78 °C in THF. Reaction mechanism is briefly discussed.
Voltammetric Characterization of α- and β-Dodecamolybdophosphates in Aqueous Organic Solutions
Authors: Himeno Sadayuki , Osakai Toshiyuki , Saito Atsuyoshi 
Published: July 2006

Abstract
The electrochemical properties of α- and β-dodecamolybdophosphates were characterized at the glassy carbon (GC) electrode. It was found that the β-isomer was only stable in neat organic solvents. When molybdophosphate was prepared in aqueous organic solutions, a mixture of α- and β-isomers formed.
A New Method for Determination of Disulfide Pairing in Peptides
Authors: Hidaka Yuji , Shimonishi Yasutsugu 
Published: July 2006

Abstract
A new method was developed for determination of disulfide pairings in peptides. This method consisted in the synthesis of peptides with deuteriocysteine residues at given positions and the analysis of deuteriocystine generated in the acid hydrolyzates of the synthetic peptides by fast atom bombardment mass spectrometry. The availability of this method was confirmed by its application for determining the positions of disulfide linkages in a heat-stable enterotoxin of enterotoxigenic Escherichia coli.
An Efficient Preparation and Reactions of [5,6′-Biguaiazulene]-3,3′(5H,6′H)-dione and 5-Isopropylidene-3,8-dimethyl-1(5H)-azulenone: Key Intermediates for the Autoxidation Products of Guaiazulene
Authors: Matsubara Yoshiharu , Matsui Shuichi , Takekuma Shin-ichi , Quo Yan Pin , Yamamoto Hiroshi , Nozoe Tetsuo 
Published: July 2006

Abstract
Oxidation of guaiazulene (1) with peracetic acid in hexane at 25 °C afforded as high as an 80% yield of the title biguaiazulenedione (12), which upon heating at 60 °C under nitrogen gave the title 1-azulenone (13) quantitatively. Oxidation of 12 and 13 was studied under various conditions, and these compounds were shown to be highly important key intermediates for a large number of the complex products obtained by autoxidation of 1.
Multi-Ionic Potential and Membrane Permeability Matrix. III. Diffusion and Concentration of Ions within Membrane Phase as a Controlling Factor to Ion Permselectivity
Authors: Kaibara Kozue , Inoue Hiroyoshi , Aritomi Toshio 
Published: July 2006

Abstract
Membrane concentrations of cations in the NaCl–CsCl and NaCl–CaCl2 systems with a highly selective cation-exchange membrane were measured under the extensive external electrolyte conditions. The modes of membrane/solution distribution and diffusion of cations, as a controlling factor to the membrane permselectivity, were correlated consistently with the electrochemical and cation flux data, as well as with the estimated membrane permselectivity parameters. The NaCl–CsCl uni-uni valent cation system was characterized well by the Na+/Cs+ concentration ratio of external solution, since the Na+/Cs+ concentration ratio in the membrane phase was related directly to the external ratio. Na+/Cs+ diffusion coefficient ratio varied from 0.5 to 3 with increasing external Na+/Cs+ concentration ratio from 1/100 to 100. While in the NaCl–CaCl2 uni-bi valent cation system, the high and constant membrane concentration of Ca2+ regulated the transport process. The Na+/Ca2+ diffusion coefficient ratio ranged from 0.5 to 500 with external Na+/Ca2+ ratio from 1/100 to 100. Analyses on the phenomenological coefficients, describing the inter-cationic correlations within the membrane phase, as a function of the external cation concentration ratio were also carried out.
Oxovanadium(V)-Induced Ring-Opening Oxygenation of Cyclic Ketones in Alcohol
Authors: Hirao Toshikazu , Mori Makoto , Ohshiro Yoshiki 
Published: July 2006

Abstract
Cyclic ketones underwent ring-opening oxygenation on treatment with VO(OEt)Cl2 in alcohol under oxygen to give the corresponding keto ester or diesters depending on the substituent at 2-position. This system was applicable to a catalytic reaction.
Synthesis and Reaction of a New Chiral Pyridoxamine Analogue; Some Doubt about the Stereochemical Process Tentatively Proposed for a Nonenzymatic Transamination Reaction
Authors: Ando Makoto , Kuzuhara Hiroyoshi 
Published: July 2006

Abstract
A pyridoxamine analogue-like chiral pyridinophane with two sulfonyl groups in the bridging chain, (S)-15-aminomethyl-14-hydroxy-2,8-dithia[9](2,5)pyridinophane S,S,S′,S′-tetraoxide ((S)-7), was prepared by oxidation of the sulfide precursor, (S)-2. The amino group was successfully transferred from (S)-7 to several 2-oxo carboxylic acids in methanol at room temperature in the presence of one-half equimolecular zinc(II) ion, giving (R)-amino acids in excess. The reaction rates of this nonenzymatic transamination using chiral (S)-7 were much smaller than those of the corresponding reaction using chiral (S)-2. The enantiomeric excess of the amino acids obtained through the reactions of (S)-7 was compared with those of (S)-2, showing that (S)-7 was more efficient than (S)-2 for the preparation of (R)-alanine, but was less than that of (S)-2 for the preparations of (R)-valine, (R)-leucine, and (R)-phenylalanine. These results aroused some doubt about the previous explanation of the stereochemical features of such nonenzymatic transamination reactions.
Alkylaion of Toluene with 2-Propanol over Titania–Silica–Alumina Catalysts
Authors: Rao K V C , Sabu K R , Nair C G R 
Published: July 2006

Abstract
The alkylating activity of titania supported on silica–alumina has been reported earlier (V. G. Kumar, T. S. Shoba, and K. V. C. Rao, Tetrahedron Lett., 26, 3281 (1985)). Further investigations to synthesize such a catalyst with optimum alkylation activity resulted in the coprecipitation of the catalyst from a solution of pH 4–the test reaction selected being the alkylation of toluene with 2-propanol in a fixed bed tubular reactor. The product mixtures at different reaction times are analyzed to have a view on the variation of yields of different alkylated products with reaction time. The alkylated products are o-cymene, p-cymene, and diisopropyltoluenes (DIT). The presence of titania exerts a synergistic effect upon the alkylating activity of silica–alumina. Also the catalytic activity is governed by the physical characteristics of the catalyst like surface area and porosity. The trend of para-rich isomer distribution observed in the product mixture is attributed to the steric factors. It has been observed that o-cymene is formed at a constant rate whereas p-cymene formation decreased with reaction time. Increased formation of diisopropyltoluenes are observed with the passing of reaction time. Alkylation studies in the temperature range 165–240 °C have been done to find the effect of reaction temperature on the product distribution. Thus a decrease in the ortho to para molar ratio with increase in reaction temperature and increased formation of diisopropyl toluenes at lower temperatures are observed. No considerable reduction in the alkylation activity has been noticed up to five regeneration cycles.