bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidation of Lipids. IX. Decomposition of Methyl Linoleate and Methyl Linolenate Hydroperoxides in Solution
Authors: Yamamoto Yorihiro , Saeki Noriyuki , Haga Schunichi , Niki Etsuo , Kamiya Yoshio
Published: July 2006

Decompositions of methyl linoleate hydroperoxide (LOOH) induced by di-t-butyl diperoxyoxalate and cobalt ions were investigated in benzene at 50 °C under vacuum to elucidate the degradation mechanism. The major products were dimer (LOOL), oxodiene, hydroxydiene and epoxyhydroxyene (and/or epoxyoxoene). It was suggested that these products were formed by the recombination of L· and LOO· radicals, β-scission of LO· radical, hydrogen abstraction of LO· radical, and intramolecular epoxidation of LOO· radical, respectively. The decomposition of methyl linolenate hydroperoxide (L′OOH) was also studied. The major products were dimer, oxotriene, hydroxytriene, and thiobarbituric acid reactive substances, which were suggested to be formed by the intramolecular cyclization of L′OO· radical.
Synthesis, and the Adjuvant and Tumor-Suppressive Activities of Quinonyl Muramyl Dipeptides
Authors: Kobayashi Shigeru , Fukuda Tsunehiko , Yukimasa Hidefumi , Fujino Masahiko , Azuma Ichiro , Yamamura Yuichi
Published: July 2006

ω-(1,4-Benzoquinon-2-yl)alkanoic acids, 2-[10-(5,6-dimethoxy-3-methyl-1,4-benzoquinon-2-yl)decyl]-3-hydroxytetracosanoic acid, all-trans-5,9,13,17-tetramethyl-4,8,12,16-octadecatetraenoic acid, and stearic acid were coupled to the 6-O-position of the carbohydrate moiety of muramyl dipeptide alkyl esters, and 6-O-aminoacylmuramyl dipeptide methyl esters. The aminoacyl residues used were Gly, Leu, Ahx, and Aud. New synthetic methods were developed for ω-(1,4-benzoquinon-2-yl)alkanoic acids such as 22-(5,6-dimethoxy-3-methyl-1,4-benzoquinon-2-yl)docosanoic acid, and the α-branched ω-(1,4-benzoquinone-2-yl) β-hydroxy acid, 2-[10-(5,6-dimethoxy-3-methyl-1,4-benzoquinon-2-yl)decyl]-3-hydroxytetracosanoic acid. The effects of the resulting quinonyl, multiprenylacetyl, and stearoylmuramyl dipetides on the induction of delayed-type hypersensitivity to ABA-Tyr in guinea pigs and the tumor(meth-A)-suppressive activity in syngeneic BALB/c female mice were measured. The results revealed that all these muramyl-dipeptide derivatives retained the adjuvant activity whereas the potent tumor-suppressive activity was observed only in quinonylmuramyl dipeptides, indicating that the 5,6-dimethoxy-3-methyl-1,4-benzoquinone ring is a requisite for the manifestation of the tumor-suppressive activity. The lipophilicity-hydrophilicity balance of the molecule was also important. Among the compounds tested, N-acetyl-6-O-[10-(5,6-dimethoxy-3-methyl-1,4-benzoquinon-2-yl)decanoyl]muramyl-l-valyl-d-isoglutamine methyl ester showed the most potent tumor-suppressive activity. This compound also showed tumor-regressive activity in guinea pigs, and hence is a good candidate for further studies.
Studies on Peptide Antibiotic “Gratisin”
Authors: Tamaki Makoto
Published: July 2006

According to a primary structure proposed for an antibiotic peptide, gratisin, four peptides containing respectively partial sequences, l-Phe–l-Pro–l-Tyr, d-Phe–l-Pro–l-Tyr, l-Phe–l-Pro–d-Tyr, and d-Phe–l-Pro–d-Tyr, were synthesized by a liquid phase method. Among them, cyclo(–l-Val–l-Orn–l-Leu–d-Phe–l-Pro–d-Tyr–)2 showed the strongest activity against the Gram-positive microorganisms tested. The activity toward Bacillus subtilis was similar to that of gramicidin S. Therefore, it is quite possible that natural gratisin is identical to this peptide. To facilitate a further investigation of the structure-activity relationship, four additional analogs were prepared. The results of their antibiotic activities showed that an interchange of d-Phe residues with d-Tyr residues caused the decrease of activity, and that the hydroxyl group of d-Tyr residues had no important role in this activity. The peptides possessing partial sequences, d-Phe–d-Tyr–l-Pro and l-Pro–d-Phe–d-Phe, exhibited strong activity. These facts show that the positions of Pro residues are not restricted to 5 and 5′ for the exhibition of the activity. The CD spectra of these synthetic peptides in an aqueous solution reflected the partial sequences around Pro residues, which affect largely the conformation of these synthetic antibiotics. The temperature dependence of these CD spectra indicated that the conformation of biologically active peptides is more stable than those of less active peptides.
Steam Reforming of Hydrocarbons and Water Gas Shift Reaction Through a Wall of Stabilized Zirconia Used as Hydrogen Separator
Authors: Otsuka Kiyoshi , Yokoyama Seiichiro , Morikawa Akira
Published: July 2006

Steam reforming of CH4 and C2H4 or water gas shift reaction was allowed to occur through a wall of stabilized zirconia acting as hydrogen separator. The reactions proceed via transport of oxygen ions in the zirconia lattice from cathode to anode of the wall, accompanying an electron transfer in the reverse direction through the outer lead wire. Hydrogen without CO2, CO, or hydrocarbons can be obtained directly by each reaction at the cathode side. The rate of hydrogen production increases exponentially with a rise in applied potentials via chromel-constantan thermocouples. The presence of reducing gas such as CO, CH4, or H2 at the anode side will decrease considerably the applied potential required to produce hydrogen at the same rate. A tentative reaction mechanism is proposed on the basis of kinetic information of the reaction.
Internal Rotation of Tetraphenylethylene Dianion as Studied by H-1 and C-13 NMR
Authors: Morikawa Masaru , Matsui Hideki , Yoshino Akihiro , Takahashi Kensuke , Miyajima Goh
Published: July 2006

The line-shape analyses of the 1H NMR spectra of the title anion have been made by means of a program of DNMR3. The thermodynamical parameters thus obtained are discussed in terms of counterions and other additives.
A Synthesis of dl-Pumiliotoxin-C
Authors: Abe Kyo , Tsugoshi Teruhisa , Nakamura Nobuo
Published: July 2006

Reductive aminocyclization of trans-2-(3-oxohexyl)-3-methyl-1-cyclohexanone (4) with sodium cyanotrihydroborate and ammonium bromide gave dl-pumiliotoxin-C (5) and its stereochemical isomer (6) in a ratio of 48:52.
Adsorption Effects of Highly Polarizable Organic Compounds on Electrode Kinetics
Authors: Ikeda Osamu , Watanabe Ken-ichi , Taniguchi Yasuhiko , Tamura Hideo
Published: July 2006

Adsorption effects of ureas and thioureas on electrode kinetics were studied by using the electrode reactions of Zn2+/Zn(Hg) and Eu3+/Eu2+. The standard rate constant for Zn2+/Zn(Hg) is controlled by the inner-layer permittivity. The effect of this permittivity has been explained in terms of the solvent reorganization energy. The effect of the adsorbates on the electrode kinetics of Eu3+/Eu2+ cannot be explained in terms of the inner-layer permittivity. These two results suggest different locations for the formation of the activated complex: Inside the adsorption layer for Zn2+ and just outside layer for Eu3+.
Interactions of Excited Lithium Atom with Molecular Hydrogen. II. Properties of Wave Functions in the Potential Crossing Region
Authors: Mizutani Kimiko , Yano Takakazu , Sekiguchi Atsushi , Hayashi Kazuko , Matsumoto Shiro
Published: July 2006

To elucidate the electronic mechanism of the quenching of electronically excited Li atoms by H2 molecules, CASSCF calculations were made regarding the Li–H2 system with various geometries. Special attention was payed to the electronic structure of the system in the crossing, or pseudocrossing, region of the potential energy surfaces. Simple CASSCF functions do not have a satisfactory spacial symmetry when the upper and the lower states are almost degenerate in energy, and need to be refined by the addition of a nonorthogonal CI. In the crossing region, electron density maps have shown that the Li atom is bonded more strongly to the nearer H atom than to the farther H atom in the ground state, whereas the opposite is the case for an excited state. Such properties of the wave function lead naturally to a picture of a nonadiabatic process occurring in the crossing region. The pseudocrossing of the first excited and the ground state potential energy surfaces has also been found for all geometries midway between the C2v and C∞v symmetries.
Colloid Chemical Studies on the Aggregation of Phospholipid Vesicles with Metal Cations
Authors: Furusawa Kunio , Kakoki Hiroyuki , Matsumura Hideo
Published: July 2006

Aggregation behavior of phosphatidylethanolamine (PE) and Phosphatidylserine (PS) vesicles that have resulted with various metal cations, has been studied to determine their adsorption characteristics. The critical flocculation concentration of these cations for both vesicles was determined by two techniques, i.e., by the kinetic method in which the rate of flocculation was measured turbidimetrically, and by the traditional static method. The results have been analysed by the usual stability concept in the colloid chemistry, and these analyses revealed that there are two mechanisms in the vesicle aggregation. One is the charge neutralization of the polar groups on the vesicle surface, which is induced by the adsorption of multivalent cations (Th4+, La3+), and the other is the interparticle binding (or the interparticle bridging) caused by the divalent cations (Ca2+, Mg2+).
Stability Constants of Scandium Complexes. II. Dicarboxylate Complexes Species
Authors: Itoh Hisako , Ikegami Yukihiro , Suzuki Yasuo
Published: July 2006

The stability constants of scandium complexes with malonate, maleate, itaconate, glutarate, adipate, and succinate ligands were determined titrimetrically at 25.0 °C and at an ionic strength of 0.1. The chelate effect was negligible for the stability of the scandium complexes with the dicarboxylate ligands studied in contrast with the lanthanoid complexes. The complex formation of scandium might be explained by an electrostatic ionic bond similar to ones exhibited in the lighter rare-earth complexes, due to linear relationships between the stability constants and the ionic potential Z2⁄r.
Oxidative Coupling of 1-(2,6-Dichlorobenzoyl)pyrroles and -pyrazoles and Alkyl Acrylates by Palladium(II) Acetate
Authors: Itahara Toshio , Kawasaki Kazukuni , Ouseto Fumio
Published: July 2006

Treatments of 1-(2,6-dichlorobenzoyl)-, 3-acetyl-1-(2,6-dichlorobenzoyl)-, 1-(2,6-dichlorobenzoyl)-2-formyl-, and 1-(phenylsulfonyl)pyrroles with palladium acetate and alkyl acrylates gave the corresponding α-alkenyl-substituted pyrroles in good yields, while the reaction of 1-(2,6-dichlorobenzoyl)-2,5-dimethylpyrrole gave small amounts of β-alkenyl-substituted pyrroles. Under similar conditions, 1-(2,6-dichlorobenzoyl)pyrazole and 1-(2,6-dichlorobenzoyl)-3,5-dimethylpyrazole reacted with palladium acetate and alkyl acrylates to give the corresponding 4-alkenyl-substituted pyrazoles. The reaction of 1-(2,6-dichlorobenzoyl)-4-methylpyrazole gave 5-alkenyl-substituted pyrazole
Exponential Distribution of Aqueous 1–1 Electrolytes Due to Convective Thermal Diffusion in Vertical Columns
Authors: Takeyama Naokata , Nakashima Kimie
Published: July 2006

Using titanium columns of 10 cm length and glass columns of different lengths, the vertical exponential distribution of the concentration of aqueous 1–1 electrolytes in each column has been ascertained at the steady state of convective thermal diffusion. The value of(a4⁄L) In q is found to be characteristic of individual solutes, and possibly proportional to the thermal diffusion coefficients, where q is the quotient of the steady concentration of a solute at the bottom of column to that at the top, L is the effective column length, and a is the working column space. This fact has been also shown by jointed glass columns with and without top vessel, capable of multistep sampling from the top to the bottom through intermediate jointed parts along columns. The rate constants in processes to the steady state have been examined to be proportional to the square of temperature difference applied, and to decrease with increasing L. Although the enhancement of downward enrichment of solutes has been observed by attaching a large top vessel to the column top, the rate constants decrease inevitably and significantly thereby.
7-Diazo-7H-benz[de]anthracene and 7H-Benz[de]anthracen-7-ylidene
Authors: Izuoka Akira , Murata Shigeru , Iwamura Hiizu
Published: July 2006

7-Diazo-7H-benz[de]anthracene has been prepared by the HgO oxidation of the corresponding hydrazone in ether. The yellow-green diazo compound in a 2-methyltetrahydrofuran matrix has been photolyzed with a high-pressure mercury lamp in an ESR cavity at 14 K. From the X, Y, and Z transitions due to the unoriented triplet species, the zero-field splitting parameters of 7H-benz[de]anthracen-7-ylidene have been determined: |D|=0.2662 and |E|=0.0175 cm−1. A temperature dependence experiment showed linear signal intensities vs. 1⁄T plots, indicating that the carbene is in the ground triplet state. The zero-field splitting parameters have been theoretically calculated by assuming the dipolar interaction of the electron spins one on the n-orbital at the 7-position and the other delocalized on the Hückel π-framework.
Photoelectron Angular Distribution for Jahn-Teller Split Bands of Some Molecules in VUV Photoelectron Spectroscopy
Authors: Shiromaru Haruo , Katsumata Shunji
Published: July 2006

Measurements of photoelectron angular distribution were carried out with NeI and HeI resonance lines for Jahn-Teller split bands of methane, ethane, cyclopropane, neopentane, tetramethylsilane, carbon tetrachloride, and ammonia. The variation of an asymmetry parameter β across the band is presented. Significant β variations across the Jahn-Teller split bands due to the l2T2 states of C(CH3)4+ and CCl4+ could not be explained in terms of photoelectron energy dependence of β. These abnormal variations will be discussed on the basis of characteristics of the degenerate molecular orbitals split by the Jahn-Teller effect.
Variational Determination of Molecular Orbital Energies in Independent Particle Models
Authors: Isihara Makoto
Published: July 2006

A simple construction formalism of molecular orbitals is presented in the context of partitioning of the electronic Hamiltonian. As a consequence of the formalism, a variational method of determining molecular orbital energies is proposed. The method is illustrated with the numerical example for the helium atom, whose result is reasonably meaningful.
Binding of 1-Decylpyridinium Bromide to Poly(vinyl sulfate)
Authors: Shirahama Keishiro , Tashiro Masatoshi
Published: July 2006

Binding of 1-decylpyridinium bromide onto poly(vinyl sulfate) in aqueous solution is measured by using a potentiometric titration method which employs propionyl-α-cyclodextrin as a neutral carrier in a 1-decylpyridinium selective electrode. Binding is highly cooperative and biphasic. The first step binding is reduced, while the second one increased on increasing added NaBr concentration. Temperaure dependence is very small giving an enthalpy of binding equal to −1.4 kJ mol−1.
Synthesis of Azobenzo-crown Ethers and Their Complexation Behavior with Metal Ions
Authors: Shiga Masanobu , Nakamura Hiroshi , Takagi Makoto , Ueno Keihei
Published: July 2006

New crown ethers which have a benzeneazo group as a building block of a macrocyclic polyether ring. The complexation properties of these new azobenzo-crown ethers with alkali and alkaline earth metal iodide salts were investigated in acetonitrile solution spectrophotometrically. The complex formation constants were evaluated for alkali metal salts. The azo group is not particularly a favorable component of a crown ether macrocycle for stabilizing the metal complexes.
Synthesis of N-Tripeptidyl-d-glucosamine by the Stepwise Reaction of N-Carboxy α-Amino Acid Anhydride
Authors: Oya Masanao , Negishi Toshiyuki
Published: July 2006

N-Peptidyl-d-glucosamines were synthesized by the stepwise reaction of N-carboxy α-amino acid anhydrides (4-alkyl-2,5-oxazolidinediones) with d-glucosamine hydrochloride in the presence of equimolar sodium methoxide in a mixture of acetonitrile and methanol, or in methanol, at a low temperature. Polymerization reaction of N-carboxy α-amino acid anhydrides (NCAs) did not occur at −50 °C. The mechanism of the reaction was then studied.
NAD(P)+–NAD(P)H Model. 47. Mechanism of the Formation of 1,4-Dihydronicotinamide in the Reaction of Pyridinium Salt and Amine
Authors: Ohno Atsuyoshi , Ushida Satoshi , Oka Shinzaburo
Published: July 2006

An amine reduces 1-benzyl-3-carbamoylpyridinium ion (BNA+) into 1-benzyl-1,4-dihydronicotinamide (BNAH) in aqueous solution. The mechanism of reduction has been elucidated. The covalently bound adduct of the amine and BNA+ at the 6-position is found to be the true reductant. The reduction with formate proceeds through the direct “hydride-transfer” mechanism. Selectivity of nucleophilic attack on the 4- and 6-positions of BNA+ is discussed in terms of hard-soft-acid-base (HSAB) principle.
Mössbauer Effect of 119Sn in Tin Sulfides Produced through Thermal Decomposition of SnS2
Authors: Ichiba Sumio , Kunita Kazushi
Published: July 2006

The intermediate tin sulfides produced through thermal decomposition of SnS2 were studied by quenching and Mössbauer spectroscopy. The thermal decomposition of SnS2 in a nitrogen gas flow proceeded to SnS via Sn2S3. The existing phases of the decomposition products in the range of the S/Sn ratio less than 1.50 were Sn2S3 and Sn1−xS. A new peak observed in the Mössbauer spectrum of tin sulfides with the S/Sn ratio less than 1.04 was assigned to Sn4+ in the nonstoichiometric compound Sn1−xS.
Kinetics of Ligand Substitution Reaction between Cyanide Ion and NiL2 (L=4-(2-Pyridylazo)resorcinol, Diethylenetriamine, and Ethylenediamine)
Authors: Bajaj Hari Chand , Phull Madhu , Nigam Prem Chandra
Published: July 2006

The kinetics of substitution reaction of cyanide ion with some bis complexes [NiL2]2−2n, where Ln− is 4-(2-pyridylazo)resorcinolate, diethylenetriamine, or ethylenediamine, to form the square planar complex [Ni(CN)4]2− has been studied spectrophotometrically in aqueous solutions. The rate expression has the form:rate={kdNiL2+k′[CN−]}[NiL22−2n], where k′ is a composite rate constant in case of par and dien and is equal to kCNNiL2 in case of en. These results indicate that these bis complexes are not directly converted into [Ni(CN)4]2− but first lose one ligand molecule and cyanide assists this loss. The backward reaction between [Ni(CN)4]2− and L is first order in each reactant and inverse first order in cyanide. Though the mechanism for the reactions appears to be same, there are kinetic differences in the behaviour of en and the other two chelates. The rate determining step for the three reactions have been identified. The activation parameters for the forward reaction have been evaluated to support the proposed mechanism. The temperature dependence of backward reaction has also been given.
Behavior of Amine in Rhodium Complex–Tertiary Amine Catalyst System Active for Hydrogenation of Aldehyde under Oxo Reaction Conditions
Authors: Mizoroki Tsutomu , Kioka Mamoru , Suzuki Masayasu , Sakatani Shiro , Okumura Atsushi , Maruya Ken-ichi
Published: July 2006

The title reaction was investigated to elucidate the reported disagreements on the kinetics. The concentration and the coordination stability of amine were found to affect the optimum pressure of carbon monoxide and the kinetics, and were suggested to control the reaction mechanism.
Catalytic Effects of Chlorate Ions on the Electrode Reaction Processes of 12-Molybdophosphate and 12-Molybdosilicate
Authors: Unoura Kei , Iwashita Atuko , Itabashi Eiki , Tanaka Nobuyuki
Published: July 2006

The third cathodic waves corresponding to the reduction processes from the four-electron to the six-electron reduction products of both 12-molybdophosphate and 12-molybdosilicate are catalytic in nature in the presence of chlorate ions. The six-electron reduction product of 12-molybdophosphate is oxidized by chlorate ions more rapidly than that of 12-molybdosilicate.
Ozonation of Xanthene
Authors: Matsui Masaki , Miyamoto Yoshihiko , Shibata Katsuyoshi , Takase Yoshimi
Published: July 2006

The ozonation of xanthene was studied using an oxygen stream. Ozone attacks the methylene group of xanthene via a 1,3-dipolar insertion reaction to give the hydrotrioxide intermediate, followed by a loss of singlet oxygen to form xanthydrol. The ozonation of xanthydrol gave singlet oxygen, water and xanthone accompanied by autoxidation.
Electrochemical Carboxylation of α,β-Unsaturated Ketones with Carbon Dioxide
Authors: Harada Junji , Sakakibara Yoshihisa , Kunai Atsutaka , Sasaki Kazuo
Published: July 2006

Several aromatic and aliphatic α,β-unsaturated ketones were converted to the corresponding γ-keto acids by the electrochemical reduction in acetonitrile in the presence of CO2. The yields of the keto acid were 73–82% when the enones have at least one aromatic substituent. In the case of aliphatic enones, the yields of the carboxylation reaction were 67% for 2-cyclohexen-1-one and 44% for 3-buten-2-one.
Generation and Reactions of 5,6-Dimethylene-2-cyclohexene-1,4-diones. A New Synthesis of Polycyclic 1,4-Benzoquinones
Authors: Kanao Yoshinori , Oda Masaji
Published: July 2006

1,2,3,6-Tetrahydrobenzocyclobutene-3,6-dione underwent thermal ring opening of the four-membered ring at 140°C to generate 5,6-dimethylene-2-cyclohexene-1,4-dione. This is a highly reactive substance and was trapped as dimers or Diels-Alder adducts giving polycyclic 1,4-benzoquinones. Intramolecular rearrangements preferably took place in some derivatves.
The Intermolecular Interaction of Tetrathiafulvalene and Bis(ethylenedithio)tetrathiafulvalene in Organic Metals. Calculation of Orbital Overlaps and Models of Energy-band Structures
Authors: Mori Takehiko , Kobayashi Akiko , Sasaki Yukiyoshi , Kobayashi Hayao , Saito Gunzi , Inokuchi Hiroo
Published: July 2006

Based on the extended Hückel molecular orbital calculations, the relation between the anisotropy of the band structure and the arrangement of the organic molecules is investigated for two organic donors, tetrathiafulvalene (TTF) and bis(ethylenedithio)tetrathiafulvalene (BEDT–TTF). The intermolecular overlaps of their HOMO are calculated while the intermolecular arrangements are varied. The maps of the overlaps thus obtained are then used to estimate the band-structure parameters of (TMTTF)2X and (BEDT–TTF)2ClO4(C2H3Cl3)0.5. The Fermi surface of (TMTTF)2X is quasi-one-dimensional and not closed. On the contrary, (BEDT–TTF)2ClO4(C2H3Cl3)0.5 is regarded as a two-dimensional semimetal.
Electrical Relaxations in Mixtures of Lithium Chloride and Glycerol
Authors: Howell F Scott , Moynihan Cornelius T , Macedo Pedro B
Published: July 2006

The dielectric constant ε′ and the electrical conductivity σ were measured as a function of frequency (0.1–2 MHz) and temperature for an electrolyte-polar solvent system: lithium chloride in glycerol. Mole fractions of LiCl were 0, 1, 2, 5, 10, 20, and 33.3%. Data were analysed in terms of an inverse complex permittivity(electrical modulus). At lower mole fractions, two separate modulus relaxations were observed, one due to the ionic diffusion and the other to the dipole reorientation. These two relaxation processes converged with increasing LiCl mole fraction and were not distinguishable at 20%. The moduli isotherms at 33.3% were characteristic of a fused salt. Average relaxation times and distributions for both processes were determined by computer fits to a Gaussian distribution in the logarithms of these times. Their temperature and mole fraction dependences are discussed. The conductivity relaxations became slightly broader than single at 10%; this shows the influence of the charge concentration on the structural relaxation process.
Volume and Adiabatic Compressibility of Amino Acids in Urea–Water Mixtures
Authors: Ogawa Toshio , Yasuda Motoo , Mizutani Kiyoshi
Published: July 2006

Apparent molal volumes (φV) and apparent molal adiabatic compressibilities (φKS) at 25 °C have been obtained for the following amino acids in water and in urea-water mixtures (up to 8 mol kg−1 urea for φV and at 3 mol kg−1 for φKS) from measurements of density and ultrasonic velocity: glycine, l-alanine, β-alanine, α-aminoisobutyric acid, l-valine, l-serine, and l-threonine. The limiting values φVo and φKSo were calculated by a linear extrapolation using the least-squares method. These data were used to derive the volumes of transfer and the adiabatic compressibilities of transfer of the amino acids from water to aqueous urea solutions. Both of these transfer functions were positive. The results were interpreted in terms of structure-breaking interaction of urea upon water.
Preparation of Graphite Fluoride by Vertical Vibrating Reactor
Authors: Watanabe Nobuatsu , Katoh Saburo , Nakajima Tsuyoshi
Published: July 2006

A study was made of the yield and crystallinity of graphite fluoride using a vertical vibrating reactor, which made it possible to prepare much graphite fluoride. The yield of graphite fluoride decreased beyond 500 °C for natural graphite and petroleum coke heat-treated at 2800 °C, and beyond 300 °C for calcined petroleum coke. The crystallinity of graphite fluoride was improved through the decomposition and refluorination process in these temperature ranges where the yield decreased. It was found that a sublimative solid by-product was formed together with gaseous fluorocarbons. It was a white solid fluorocarbon with 5–9 cyclohexane rings.
Indole Syntheses Utilizing o-Methylphenyl Isocyanides
Authors: Ito Yoshihiko , Kobayashi Kazuhiro , Seko Norihiko , Saegusa Takeo
Published: July 2006

New indole synthesis starting with o-methylphenyl isocyanides such as o-tolyl, 2,4-xylyl, and 2,6-xylyl isocyanide is described in full detail. Treatment of o-tolyl isocyanide with LDA in diglyme at −78 °C generated selectively o-(lithiomethyl)phenyl isocyanide in an almost quantitative yield, which on warming up to room temperature was cyclized to indole after aqueous workup. Similary, 2,4-xylyl and 2,6-xylyl isocyanides were cyclized to 5-methylindole and 7-methylindole quantitatively. The o-(lithiomethyl)phenyl isocyanides reacted with electrophiles such as alkyl halides and alkylene oxides to give o-alkylphenyl isocyanides, which were cyclized via the lithiation at the orthobenzylic carbon to afford 3-substituted indoles. On the other hand, the o-(lithiomethyl)phenyl isocyanides generated in situ at −78 °C was first warmed up to room temperature and then treated with electrophiles to furnish 1-substituted indoles. The o-(lithiomethyl)phenyl isocyanides were acylated in a fairly good yield with N-acylaziridines to give o-(acylmethyl)phenyl isocyanides, which were readily alkylated in the presence of sodium hydride to produce o-(1-acylalkyl)phenyl isocyanides. On acid hydrolysis followed by neutralization, o-(1-acylalkyl)phenyl isocyanides were converted to 2,3-disubstituted indoles.
The Synthesis of Coleon B Tri-O-methyl Ether
Authors: Matsumoto Takashi , Imai Sachihiko , Nishizaki Katsumi , Kurihara Fumio , Goto Fumitaka
Published: July 2006

Methyl (+)-12-benzoyloxy-11,14-dioxo-8,12-abietadien-18-oate was converted into methyl 11,12,14-trimethoxy-8,11,13-abietatrien-18-oate (8). The Grignard reaction of 8 with phenylmagnesium bromide, followed by oxidation with lead tetraacetate, afforded 11,12,14-trimethoxy-19-norabieta-4(18),8,11,13-tetraene. This was then converted into 3α-bromo-11,12,14-trimethoxy-18-norabieta-8,11,13-trien-2-one (15) by a series of reactions: selenium dioxide oxidation, catalytic hydrogenation, dehydration, hydroxybromination, and Jones oxidation. Acetalization of 15 with 1,2-ethanediol, followed by oxidation with Jones reagent and then with oxygen in the presence of potassium t-butoxide, afforded 3-bromo-2,2-ethylenedioxy-6-hydroxy-11,12,14-tri-methoxy-18-norabieta-5,8,11,13-tetraen-7-one, which was converted into (−)-coleon B tri-O-methyl ether (4) by hydrolysis and dehydrobromination. Another conversion of 15 into 4 was also achieved by a series of reactions: debromination, acetalization, Collins oxidation, oxygen oxidation, hydrolysis, and dehydrogenation.
Preparation and Crystal Structure of Bis[(2-aminoethyl)dimethylphosphine][1,2-bis(dimethylphosphino)ethane]cobalt(III) Tribromide Dihydrate, [Co{NH2CH2CH2P(CH3)2}2-{(CH3)2PCH2CH2P(CH3)2}]Br3·2H2O
Authors: Ohishi Tomoji , Ohba Shigeru , Kashiwabara Kazuo , Saito Yoshihiko , Fujita Junnosuke
Published: July 2006

The title compound has been prepared and the crystal structure determined by the X-ray diffraction method. The complex ion is the trans(P, N) isomer, where one of the N atoms of (2-aminoethyl)dimethylphosphine (edmp) occupies the position trans to the P atom of the other edmp ligand.
Synthesis of 1,2-Polymethyleneimidazoles Utilizing Intramolecular Ring Transformation
Authors: Sasaki Tadashi , Ohno Masatomi , Ito Eikoh
Published: July 2006

Among the intramolecular cyclodehydration of 2-(β-, δ-, and ε-aminoalkyl)oxazoles, 2-(δ-aminoalkyl)oxazoles afforded the desired 1,2-tetramethyleneimidazoles on pyrolysis, while 2-(β- and ε-aminoalkyl)oxazoles unchanged under the same conditions.
Cycloaddition of Vinyl Isocyanate to 1,3-Dipoles
Authors: Ohshiro Yoshiki , Komatsu Mitsuo , Okamura Aiichiro , Agawa Toshio
Published: July 2006

1,2-Cycloadditions of 3-methyl-1-(methylthio)-1-butenyl isocyanate with N-t-butyl-α-toluenimine N-oxide and with in situ-generated N-t-butyl-α-methyl-α-lactam afforded an oxadiazolidinone derivative and a hydantoin derivative in 100 and 46% yields, respectively.
Effects of Dispersion in Carbon Monoxide Adsorption and Carbon Monoxide Hydrogenation over Alumina-supported Ruthenium Catalysts
Authors: Okuhara Toshio , Kimura Tomoo , Kobayashi Kenji , Misono Makoto , Yoneda Yukio
Published: July 2006

Ru/Al2O3 catalysts prepared from [Ru3(CO)12] and from RuCl3 were characterized by chemisorption of H2 and CO, and by infrared measurement of adsorbed CO. By using these catalysts, the effect of the dispersion on the activity and selectivity in CO hydrogenation was studied. Ru/Al2O3 catalysts prepared from [Ru3(CO)12] showed high dispersions (>80%), and were more active and selective for the production of olefins in the CO hydrogenation than Ru/Al2O3 catalysts prepared from RuCl3. However, the distribution of product hydrocarbons was not sensitive to the Ru dispersion. Infrared study of adsorbed CO revealed that twin-type CO (Ru(CO)2) as well as linear-type CO (Ru–CO) was present on each Ru/Al2O3. The twin-type CO was more strongly held and was less reactive to hydrogenation. For each series of Ru/Al2O3, the turnover frequency increased as the dispersion decreased. This change has been explained by the poisoning effect of the twin-type CO. The higher activity of Ru/Al2O3(A) was ascribed to the lower concentration of the twin-type CO on the surface.
Optically Active and Racemic Glycerides. II. Thermodynamic Studies on the Polymorphic Transition of (R)- and (RS)-1,2-Diglycerides
Authors: Iwahashi Makio , Ashizawa Kazuhide , Ashizawa Miyuki , Kaneko Yoshihide , Muramatsu Mitsuo
Published: July 2006

The polymorphic relationship between optically active (R)- and for racemic (RS)-forms of 1,2-distearin and 1,2-dipalmitin were studied by X-ray diffraction, infrared spectrum, and the thermal analysis. These glycerides have two crystalline forms, α and β, wherein α is metastable and β is stable under ordinary conditions. The α→β transformation for the (RS)-1,2-distearin crystal was extremely slow as compared with that for the (R)-form crystal, implying that the β-form crystal of (RS)-1,2-distearin is an eutectic mixture of small (R)- and (S)-crystals while the α-form crystal of (RS)-1,2-distearin is composed of a replacement type solid solution of (R)- and (S)-1,2-distearin molecules. Almost the same results were obtained with 1,2-dipalmitin, for which the rate of α→β transformation is higher than that for the 1,2-distarin, probably because of a higher mobility of this compound.
The Use of N,N-Dimethylformamide–Sulfonyl Chloride Complex for the Preparation of Thiophenesulfonyl Chlorides
Authors: Sone Tyo , Abe Yukio , Sato Norio , Ebina Manabu
Published: July 2006

A 1:1 N,N-dimethylformamide–SO2Cl2 complex was found to be a useful agent for the one-step preparation of thiophenesulfonyl chlorides.
Temperature Effect on Transference Numbers for KCl in Ethanol–Water Mixtures
Authors: Ueno Masakatsu , I Sh\={o}go , Shimizu Kiyoshi
Published: July 2006

Cation-transference numbers were determined by the moving boundary method for 0.02 mol dm−3 KCl in 5-, 10-, 15-, 20-, and 30 mol% ethanol–water mixtures at 15 and 35 °C. The cation-transference number has a maximum around 10 mol% of ethanol at each temperature studied, and becomes larger with decreasing temperature in the solvent of the same composition. From the temperature dependence of the transference number, the differences in the activation energy of transport between K+ and Cl− ions were estimated, and it was found that the activation energy of the K+ ion is less than that of the Cl− ion and the difference becomes larger in the range of 5–20 mol% of ethanol. These results are discussed in terms of structural effects and ion-solvent interactions.
A New Calibration Method for the Measurement of CCl4 Concentration at 10−10 v/v Level and the Behavior of CCl4 in the Atmosphere
Authors: Yokohata Akihito , Makide Yoshihiro , Tominaga Takeshi
Published: July 2006

A new technique was developed for the accurate determination of atmospheric CCl4 at about 100 pptv (=10−10 v/v) concentration level, since at such extremely low concentration CCl4 was found to be adsorbed readily and strongly on clean metal surfaces under dry conditions. The analysis of CCl4 by gas chromatography/electron-capture detector and the preparation of CCl4 primary calibration standard were improved by introducing water vapor into the system to prevent the adsorption of CCl4 and to obtain stable and reproducible results. The total amount of CCl4 in the atmosphere was studied on the basis of our newly calibrated data of CCl4 concentration, and a reasonable lifetime of CCl4 was obtained assuming that its sink is only the UV photodissociation in the stratosphere.
Photoelectrochemical Reduction Products of Carbon Dioxide at Metal Coated p-GaP Photocathodes in Aqueous Electrolytes
Authors: Ikeda Shoichiro , Yoshida Makoto , Ito Kaname
Published: July 2006

In order to increase the current efficiency of the photoelectrochemical reduction of CO2 in aqueous electrolytes, metals such as Pb and Zn, which have a higher overpotential for the hydrogen evolution reaction, were coated on a p-GaP photocathode by sputtering and electroplating. Au was also coated by sputtering. Then, the photoelectrolytic experiments were carried out in a gas-tight cell with a cyclic gas-flow system. The products in a gas phase were determined as well as the products in the electrolyte. Accordingly, CO in addition to HCOOH as a reduction product of CO2 was found to be produced as well as substantial amount of H2 as a by-product. However, other products such as HCHO and CH3OH were not found at all. In the case of the Pb coated p-GaP electrode, the current (faradaic) efficiency, η, for HCOOH formation was increased up to 48.2%, although in the case of bare p-GaP it was only 4.8% at maximum. On the other hand, the η for CO formation at the Zn-coated p-GaP electrode went up to 16.5%. While, in the case of an Au-coated p-GaP, the η for the CO2 reduction was not so changed as for the bare p-GaP photocathode.
Amide Ion Formation and N-Alkylation of Aminoanthraquinones in the Presence of Potassium Hydroxide in Dimethyl Sulfoxide
Authors: Arai Sadao , Kato Seijiro , Hida Mitsuhiko
Published: July 2006

Amide ions were formed by the deprotonation of the amino group of amino- and (monoalkylamino)anthraquinones in the presence of powdered potassium hydroxide in dimethyl sulfoxide (DMSO). Under a nitrogen atmosphere these amide ions changed to their radical anions. The amide ions of 1-aminoanthraquinones reacted with excess alkyl halides to yield 1-alkylaminoanthraquinones, while the N-alkylation of 2-aminoanthraquinones afforded 2-dialkylaminoanthraquinones in good yields. 2-Aminobenzophenone underwent mono-N-alkylation, while 4-aminoazobenzene and p-nitroaniline underwent di-N-alkylation. It was also found that the carbanion of DMSO easily attacked the carbonyl group of the (dialkylamino)anthraquinones.
Synthetic Photochemistry. XXIX. A Convenient Preparation of 1,2,3-Substituted Cyclopentenes from the Photoadducts of Methyl 2,4-Dioxopentanoate–Isoprene
Authors: Kato Nobuo , Takeshita Hitoshi
Published: July 2006

Photoadducts obtained by cycloaddition of isoprene with methyl 2,4-dioxopentanoate were converted to cyclopentene derivatives. The stereochemistry of the intermediate glycols was estabilished by chemical correlations to each other; only the cis-glycols were convertible to the cyclopentenes under the conditions employed, suggesting a fore-going acetylation of the hindered glycol functions.
Synthesis of cis-transoid-cis- and cis-cisoid-cis-Tricyclo[6.3.0.02,6]undecan-1-ols
Authors: Kakiuchi Kiyomi , Takeuchi Hideyuki , Tobe Yoshito , Odaira Yoshinobu
Published: July 2006

Two isomeric linear triquinanes, cis-transoid-cis- and cis-cisoid-cis-tricyclo[6.3.0.02,6]undecan-1-ols, were effectively synthesized by means of the modified Barbier cyclization.
The Solution Chemistry of Organotin Compounds. III. A Thermodynamic Study of the Molecular Interaction of Me2SnCl2 with Lewis Bases by Means of Nuclear Magnetic Resonance Spectroscopy
Authors: Fujiwara Hideaki , Sakai Fumihiko , Mikawa Yoshihiro , Sasaki Yoshio
Published: July 2006

Molecular interaction of Me2SnCl2 with Lewis bases has been investigated by measuring the concentration and temperature dependence of NMR coupling constant 2J(119Sn,H). It is found that 1 : 1 and 1(acid):2(base) complexes are formed concurrently in solution. Association constants and coupling constants in these complexes are determined at different temperatures, leading to the enthalpies ΔH° and entropies ΔS° for the relevant molecular interaction. The coupling constants are temperature independent and a merit of using this constant as a diagnostic tool has been proven. The E and C parameter treatment of ΔH°AB has given reasonable EA and CA values for Me2SnCl2. Entropies ΔS° are also estimated in gas phase on the basis of molecular theory for the third-law entropy, and the contribution from solvation is shown important in the solution of CHCl2CHCl2.
Kinetics of Heterogeneous Photocatalytic Decomposition of Phenol over Anatase TiO2 Powder
Authors: Okamoto Ken-ichi , Yamamoto Yasunori , Tanaka Hiroki , Itaya Akira
Published: July 2006

The photocatalytic decomposition of phenol over anatase TiO2 powder followed the first-order kinetics, upto high conversions, of which the apparent rate constant kap depended on initial concentration of phenol [phenol]0, [TiO2], O2 pressure pO2, and incident light intensity I. The dependence of the initial reaction rate Ω0 on [phenol]0 showed characteristic curvature convex to the concentration axis. The pO2 dependence of both Ω0 and kap was very similar each other and showed characteristic curvature to the pO2 axis. The dependence of both Ω0 and kap on [phenol]0 was affected by the [TiO2] and I. Both Ω0 and kap were proportional to I below ca. 1×10−5 mol m−2 s−1 and to I1⁄2 above 2×10−5 mol m−2 s−1. The activation energy was 10 kJ/mol. The results were satisfactorily explained by the equation;

Ω=φ·OHIan\fracKO2pO21+KO2pO2·\frac[phenol][phenol]0+β,

where Ω is the reaction rate; φ·OHIan, a parameter related to the formation rate of ·OH radicals or real reactive species; KO2, the equilibrium constant of Langmuir adsorption of O2; β, the ratio of the combined first-order rate constant of the reaction of ·OH with species other than organic compounds to the second-order rate constant of the reaction of ·OH with phenol.
Formaldehyde Electro-oxidation on Copper Metal and Copper-based Amorphous Alloys in Alkaline Media
Authors: Machida Ken-ichi , Enyo Michio
Published: July 2006

Copper metal and copper-based amorphous alloys, a-Cu35Ti65 and a-Cu33Zr67, exhibit a very high and stable activity for the anodic HCHO oxidation in aqueous NaOH and Na2CO3. The oxidation current was already observable at electrode potentials as low as 0.1 V (RHE) and, in particular, the HF-treated amorphous alloys gave high current densities around 40 mA cm−2 (apparent) at 0.2 V. Kinetic data, roughly first order both in HCHO and OH− concentration, are in favour of the mechanism in which the oxidation proceeds via hydroxymethanolate ion (HOCH2O−) formed from HCHO and OH−, producing HCOO− and H2: This ion is readily oxidized on the copper metal or copper-based amorphous alloy electrodes. The Tafel slope was in general agreement with the reaction mechanism assuming a rate-determining one-electron transfer step.
Crystal Structure of 6-[6(e)-Carbamoyltetrahydro-2(e)-pyranyl]8-oxa-6-azabicyclo[3.2.1]octan-7-one
Authors: Yamane Takashi , Nanayama Hiroto , Ashida Tamaichi , Hashimoto Kazuhiko , Sumitomo Hiroshi
Published: July 2006

The structure of the dimerization product of bicyclic oxalactam, 8-oxa-6-azabicyclo[3.2.1] octan-7-one, was determined by the X-ray diffraction method. The final R value was 0.062 for 2009 reflections. The structure suggests that the cationic oligomerization of the bicyclic oxalactam proceeds through the C5–N6 scission, differing from the cases of other common lactams.
Photocatalytic Isomerization of Butenes over ZnO and SnO2
Authors: Kodama Sukeya , Yabuta Masaaki , Anpo Masakazu , Kubokawa Yutaka
Published: July 2006

It has been found with ZnO as well as TiO2 that 2-butene is much more reactive than 1-butene for their photocatalytic isomerization. Although both cis-trans and double bond isomerizations take place on ZnO, only cis-trans isomerization occurs over SnO2. The photocatalytic isomerizations were suppressed drastically in the presence of NO. From those results together with the ESR studies the following conclusions emerge: a butene molecule interacts with the photoformed O− to form a radical species as a result of fission of the C=C bond; the photocatalytic isomerization proceeds via such a radical intermediate; the lack of the reactivity of 1-butene appears to be explicable on such basis.
The Stereochemistry of the Six Geometrical Isomers of the Bis(ethylenediamine-N-acetato)cobalt(III) Ion, [Co(edma)2]
Authors: Ama Tomoharu , Kawaguchi Hiroshi , Yasui Takaji , Matsumoto Keiji , Ooi Shun’ichiro
Published: July 2006

All of the six geometrical isomers possible in [Co(edma)2]+ (edma: ethylenediamine-N-acetate) were isolated, and the five chiral isomers were resolved into optically active isomers by a column-chromatographic method. Their structures were determined on the basis of the X-ray analysis and the visible absorption, 1H NMR, and CD spectral data. One of the methylene protons in the glycinate-ring of the facially coordinating edma is stereospecifically exchanged by a deuteron in the basic D2O solution, and its deuteration rate is influenced by the ligating atoms in the trans position. A 1H NMR method to determine the absolute configurations of the optically active isomers, which contain the stereospecifically deuterated edma, is reported and applied to the [Co(edma)2]+ systems. The relationship between the absolute configurations and the CD spectral behaviors of these complexes is also discussed.
Conductometric and Potentiometric Studies of the Association of α-Cyclodextrin with Ionic Surfactants and Their Homologs
Authors: Satake Iwao , Ikenoue Tadashi , Takeshita Tokuro , Hayakawa Katumitu , Maeda Tamaki
Published: July 2006

The conductometric determination was made of the association constants of α-cyclodextrin (αCD) with ionic surfactants and their homologs. For 1-alkanesulfonate ions with carbon atoms (n) of 5–12, the association constant was found to increase regularly with n and become abruptly constant at n=10. The association constants for sodium 1-dodecanesulfonate, dodecylammonium chloride, dodecyltrimethylammonium chloride, and 1-dodecylpyridinium chloride were all similar in their magnitude. The effect of complexation on the micellar properties of sodium dodecyl sulfate and dodecyltrimethylammonium chloride were also studied potentiometrically by determining the counterion activities. In both cases, the critical micelle concentration increased regularly, while the degree of counterion association to the micelle decreased almost linearly with increasing αCD concentrations. It was suggested that the αCD-surfactant ion complex is solubilized in the hydrophilic surface region of surfactant micelle to give rise to a decrease in the surface charge density.
Reactions of NH Radicals. IV. Photolysis of HN3 in the Presence of CH4 at 313 nm
Authors: Kodama Sukeya
Published: July 2006

The photolysis of HN3 vapor in the presence of CH4 was studied at 313 nm, 30 °C, and a low light intensity. The reaction products were N2, H2, NH4N3, CH3NH2·HN3, and CH3N3. CH3 radicals were also detected as intermediates. The quantum yields of these products were measured as a function of the CH4 and HN3 pressures. The following mechanisms for the main reactions were proposed: HN3+hν(313nm)→N2+NH(a1Δ); NH(a1Δ)+HN3→2N2+2H(2a); NH(a1Δ)+HN3→N3+NH2 (2b); NH(a1Δ)+HN3→N2+N2H2* (2c); NH(a1Δ)+ CH4→CH3NH2* (3); NH(a1Δ)+CH4→NH(X3Σ−)+CH4 (4); CH3NH2*→H+CH2NH2 or CH3NH (5); CH3NH2*→CH3+NH2 (6). The rate-constant ratios at 30°C were: k3⁄k2=0.175; k4⁄k2=0.177; k6⁄k5=0.133. The collisional deactivation of CH3NH2* was not found in the total pressure range, from 6.4 to 24.3 kPa.
Formation and Reactions of 2-Substituted 4,4-Dimethyl-5(4H)-oxazolones. The 5(4H)-Oxazolone as a Stable Intermediate in Peptide Bond Formation
Authors: Narita Mitsuaki , Ishikawa Kazunori , Kudo Koji , Endo Takeshi
Published: July 2006

The reaction of Boc–Leu3–Aib–OH with H–Leu3–OBzl using DCC as a coupling reagent proceeded via the exclusive 2-substituted 4,4-dimethyl-5(4H)-oxazolone formation followed by a slow aminolysis. Similar treatment of Boc–Leu3–Aib–OH with DCC in the presence of p-nitrophenol did not produce a p-nitrophenyl ester, but produced the 2-substituted 4,4-dimethyl-5(4H)-oxazolone (1) in a high yield within 20 min. The high potential for the oxazolone formation of Boc–Leun–Aib–OH (n=3 and 4) is apparently attributed to the conformational effect of C-terminal Aib residues, namely, the restriction of the backbone dihedral angles φ and ψ of Aib residues. Ring-opening reactions of oxazolones with hydroxy compounds were easily monitored by following the disappearance of the intense oxazolone peak at 1820 cm−1. The oxazolone (1) reacted faster with HOSu than H–Leu3–OBzl, followed by the slow aminolysis of the succinimide ester produced. In contrast, HOBt did not react with the oxazolones derived from Boc–Leu3–Aib–OH (n=3 and 4), but strongly catalyzed the aminolysis of the oxazolones in dichloromethane to form peptide bonds in nearly quantitative yields. A little catalytic effect of acetic acid on the oxazolone aminolysis indicated that the oxazolone aminolysis in the presence of HOBt did not proceed through a simple acid catalytic pathway, but proceeded through a biphilic (electrophilic–nucleophilic) pathway.
Stereochemical Study on 1,3-Dipolar Cycloaddition Reactions of Heteroaromatic N-Ylides with Unsymmetrically Substituted Olefinic Dipolarophiles
Authors: Tsuge Otohiko , Kanemasa Shuji , Takenaka Shigeori
Published: July 2006

Regioselectivity and stereoselectivity of the cycloadditions of heteroaromatic N-ylides with unsymmetrically-substituted olefins such as methyl-substituted cis olefins, an acrylate, the related olefins, trans nitro olefins, and other trans olefins have been investigated. These cycloadditions are highly regioselective, while the stereoselectivity depends upon both the electronic and steric nature of substituents of the ylide and olefin. The 1-endo-2-exo cycloadducts of the anti form of ylides which have been formed as kinetically controlled products undergo the isomerization into either the 1-endo-2-exo cycloadducts of the syn ylides through a retro cycloaddition process or the 1-exo-2-endo cycloadducts of the syn ylides via betaine intermediates.