bluuebunny/crossref_metadata_2025 huggingface dataset:
Syntheses of Lividomycin B Analogues, 5-O-[3-O-(6-Amino-6-deoxy-β-l-idopyranosyl)-β-d-ribofuranosyl]-3′-deoxyparomamine and ribofuranosyl]-3′-deoxyparomamine
Authors: Torii Takahiro , Tsuchiya Tsutomu , Watanabe Isamu , Umezawa Sumio
Published: July 2006

The preparation of lividomycin B analogues, the title pseudotetrasaccharides, is described. Condensation of 6-azido-2,3,4-tri-O-benzyl-6-deoxy-l-idopyranosyl chloride with 4′,6′-di-O-benzoyl-5-O-(5-O-benzoyl-β-d-ribofuranosyl)-3,2′-bis(N-benzyloxycarbonyl)-1-N:6-O-carbonyl-3′-deoxyparomamine was followed by deblocking and reduction of the azido groups. Structure determinations and the antibacterial activities of the products are described.
Preferential Crystallization of 2-Amino-2-phenylethanol and Its Application as a Resolving Agent
Authors: Saigo Kazuhiko , Miura Hisao , Ishizaki Kozi , Nohira Hiroyuki
Published: July 2006

(±)-2-Amino-2-phenylethanol (phenylglycinol) prepared from (±)-2-amino-2-phenylacetic acid (Dl-phenylglycine) by lithium aluminium hydride reduction was efficiently resolved into a pair of optically active forms by preferential crystallization. The optically active amino alcohol was successfully applied as a basic resolving agent to the resolution of tartaric acid, 2-hydroxy-2-phenylpropionic acid, 2-hydroxy-3-phenylpropionic acid, 2-phenylpropionic acid, and 2-phenyl-2-ureidoacetic acid.
Synthesis of Aubergenone, a Sesquiterpenoid Phytoalexin from Diseased Eggplants
Authors: Murai Akio , Abiko Atsushi , Ono Mitsunori , Masamune Tadashi
Published: July 2006

The synthesis of aubergenone, a stress metabolite isolated from diseased eggplants, from α-cyperone, which implies revision of the assigned structure to the metabolite, is described.
Kinetic Studies on the Amination of Leucoquinizarin
Authors: Kikuchi Masashi , Yamagishi Takamichi , Hida Mitsuhiko
Published: July 2006

Leucoquinizarin reacts with amines to give mono- and diaminoanthraquinones. The amination mechanism of leucoquinizarin was investigated on the basis of the kinetics and structures of leuco compounds. The amination reaction of leucoquinizarin was characterized as follows. This amination proceeded in polar solvent but not in nonpolar solvent at all. The reaction rate was not influenced by the addition of a small amount of water (95% ethanol) but enhanced largely in 80% ethanol. This amination reaction has a low activation energy (ΔE\eweq=5.7–9.0 kcal mol−1) and an extraordinarily small pre-exponential term (A=103–105 l mol−1 min−1). Leucoquinizarin was proposed to be aminated by the addition of amine to carbonyl group at its 1,4-position. The oxidation of leuco monoaminohydroxyanthraquinone was also examined.
Synthesis of 3-Aminonocardicinic Acid, the Basic Nucleus of Nocardicins
Authors: Hatanaka Minoru , Noguchi Noriyoshi , Ishimaru Toshiyasu
Published: July 2006

A short and high-yielding synthesis of optically active 3-aminonocardicinic acid (3-ANA) is described. The fourth component condensation reaction of N2-protected l-2,3-diaminopropanoic acid with p-benzyloxybenzaldehyde and butyl isocyanide gave directly the amide derivatives of 3-ANA, as a diastereomeric mixture, which was, after conversion of the amide group into the benzhydryl ester, led in good yield to a single disatereomer with natural chirality via epimerization. Deprotection of the 3-ANA derivative gave 3-ANA.
The Enrichment of Tritium in Hydrogen or Deuterium by Thermal Diffusion
Authors: Takayasu Osamu , Makino Ikuro , Yamagami Susumu , Takeuchi Toyosaburo
Published: July 2006

Tritium in H2 or D2, 1.7×10−2 Ci mol−1, was enriched by means of thermal diffusion at the bottom of a 100-cm glass column with a gas reservoir on top. Four columns with different diameters (8, 20, 30, and 41 mmφ) were used. The temperature of the wire stretched along the axis of the column was changed over a range from 200 °C to 450 °C. The maximum equilibrium separation factors in hydrogen and in deuterium were 17 and 4.5 respectively. The optimum diameters were estimated by a modification of Waldmann’s equation, which can be used for the separation using the flat-type system.
Electronic Structure of Transition Metal Complexes. III. A Comparative Study of Bondings in Metal Porphyrins
Authors: Kai Eiko , Nishimoto Kichisuke
Published: July 2006

In order to elucidate π-type interaction between the metal and the ligand, the electronic structure of various metal porphyrins, [M(Por)], where M=Mn, Fe, Co, Ni, and Cu, has been investigated by the CNDO/2 method. The present calculation shows that the nature of σ-type interaction in M–N bond of porphyrin complex is similar to that of the corresponding ammine complex. The calculated ionization potentials reproduce the experimental data. The electron population of macrocycle π-electron systems in metal porphyrins is about 18 which accords with Hückel’s 4n+2 rule.
The Effect of Diluents on the Mechanochemical Change in the Solid State of Amobarbital
Authors: Ikekawa Akiko , Hayakawa Sohachiro
Published: July 2006

The effect of ball-milling with dextran 2000, microcrystalline cellulose, or methylcellulose (MC) on the solid state of amobarbital was investigated. There are three kinds of polymorphs for amobarbital; Crystals I, II, and III. Crystal I is obtained by heating Crystal II recrystallized from a 25 v/v % aqueous ethanol solution at 150 °C. The part of Crystal I decreased remarkably at the first stage of ball-milling, while the amorphous part increased gradually. The heat of fusion decreased remarkably; this was considered to be due to the increase in the amorphous part. The peak of fusion in the DTA thermogram was broadened, and the temperature at which amobarbital began to fuse was lowered. This phenomenon was considered to be due to the increase in the lattice imperfection. The solubility in the KH2PO4–Na2HPO4 buffer solution with a pH of 6.0 increased; the increase in the amorphous part was considered to contribute to this increase. This phenomenon was the most remarkable in the case of the mixture with MC. The interaction of amobarbital with MC was suggested by the heat of fusion and the DTA thermograms. It was also suggested that the interaction of amobarbital with the diluent was one of the most important reasons for the increase in the solubility upon ball-milling.
High-overtone Spectra and Dipole Moment Functions for the C–H Stretching Vibration of Chloroform
Authors: Hyodo Shi-aki , Tamagake Keietsu , Fujiyama Tsunetake
Published: July 2006

The absorption spectra of liquid chloroform were observed for the C–H stretching fundamental vibration and its overtones up to v=←50. The spectral parameters were analyzed on the basis of the one-dimensional local mode representation, which led to the determination of the mechanical and electrical anharmonicities. The solvent effects on the absorption intensities are discussed from the viewpoint of the solvent effect on the dipole moment function. The finally obtained dipole moment function was compared with that obtained by the ab initio calculation.
The Viscosities of Aqueous Solutions Containing Metal Complexes. IV. Nitrilotriacetato Complexes
Authors: Mizutani Kiyoshi , Yasuda Motoo
Published: July 2006

Viscosity B-coefficients of bivalent metal complexes formed with nitrilotriacetic acid (H3nta) were determined with Cannon-Fenske capillary viscometers at 25±0.01 °C. The B-coefficients obtained are smaller for metal chelates having larger stability constants, and larger for metal chelates having smaller stability constants.
Synthesis and Circular Dichroism Spectra of mer(N)-cis(NH3)-[Co(OO)(NH3)2(py)(H2O)]+ and mer(N)-[Co(OO)(en)(py)(H2O)]+ Complexes
Authors: Fujinami Shuhei , Tsuji Kenshi , Minegishi Kumiko , Shibata Muraji
Published: July 2006

The mer(N)-cis(NH3)-[Co(OO)(NH3)2(py)(H2O)]+ and mer(N)-[Co(OO)(en)(py)(H2O)]+ complexes (OO=ox2− or mal2−) have been prepared and optically resolved. The CD spectra are different. The difference seems to be due to the additional optical activity derived from the helical arrangement of two bidentate ligands in the latter ethylenediamin complexes.
Studies of 8-Quinolinethiol as Chelating Agents, III. Distribution Behavior of 8-Quinolinethiol between Chloroform and Aqueous Solutions
Authors: Sekido Eiichi , Kobayashi Tadashi , Masuda Yoshitaka
Published: July 2006

The distribution behavior of 8-quinolinethiol between chloroform and aqueous solutions was examined and compared with that of 8-quinolinol. The distribution coefficient was KDR=2140 and macroscopic acid dissociation constants were pKa1=2.05 and pKa1=8.39.
Cycloadditions of Constrained Dicyclopropylethylenes and Divinylcyclopropanes with Tetracyanoethylene
Authors: Nitta Makoto , Kuroki Toshio
Published: July 2006

2,4-Dimethyl-7-methylenetetracyclo[3.3.-0.0.2,804,6]octan-3-one and its corresponding alcohol were reacted with TCNE to give π2+π2 cycloadducts at the exomethylene group. On the other hand, 1,5-dimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-one did not react with TCNE, whereas its corresponding alcohol and 1,5-dimethyl-6,8-dimethylenetricyclo[3.2.1.02,7]oct-3-ene afforded π2+π2 cycloadducts. The reactivities were correlated with the 13C-NMR data of the exomethylene groups, the electron densities of which are affected by the carbonyl group.
Upon DNP-aromatic Rule. Effect of Chromophore Exchange on the CD Spectra of N-DNP-arylalkylamines
Authors: Kawai Masao , Nagai Ukon
Published: July 2006

CD spectra of the analogs of aromatic DNP-α-amino acids and the related N-DNP-arylalkylamines, in which the positions of the two chromophoric groups were exchanged with each other, were studied. The analogs, in which the DNP-amino group is separated from the asymmetric carbon, did not show any marked Cotton effect near 400 nm, indicating the importance of direct attachment of the DNP–NH group to the chiral carbon atom for showing the characteristic CD spectra of N-DNP-aromatic α-amino acids.
Carbon-Carbon Bond Formation by the Use of Chloroiodomethane as a C1 Unit. IV. The Mannich Reaction of Ketones by Means of Dihalomethane and Secondary Amine
Authors: Miyano Sotaro , Mori Akira , Hokari Hiroshi , Ohta Katsuaki , Hashimoto Harukichi
Published: July 2006

Treatment of ketones with dihalomethane (CH2Br2, CH2ClI, and CH2I2) in the presence of secondary amine, preferably pyrrolidine, gave the corresponding Mannich base in varing yields depending on the substrate and/or combination of the reagents.
Weathering of H3BO3–ZnO Bond for Forming Glass Fiber Reinforced Composite
Authors: Utsumi Yoshikazu , Murakami Tadaki , Ishii Isao
Published: July 2006

H3BO3–ZnO bond stored in humidity above 75% causes the bending strength of a fiber reinforced composite to decrease. The lowering behavior corresponds to formation of 2ZnO·3B2O3·7H2O and to a decrease of H3BO3. The weathering of the bond is attributed to the decreasing of H3BO3, which becomes liquid during hot pressing.
Conformational Change of Delta-chymotrypsin Caused by Sodium Dodecyl Sulfate as Studied by Stopped-flow Circular Dichroic Method
Authors: Takeda Kunio
Published: July 2006

The conformational change of delta-chymotrypsin was studied in a sodium dodecyl sulfate (SDS) solution containing 3.33 mmol/dm3 NaH2PO4 and 3.56 mmol/dm3 Na2HPO4 (pH 7.0, μ=0.014) by means of the circular dichroism (CD) and absorbance stopped-flow methods. The protein adopts a conformation with a higher helix content than the native state upon the addition of SDS. The rate of the conformational change strongly depends on the SDS concentration. The corresponding rate constant sharply increases in the range of 5–12 mmol/dm3 SDS, indicating that the higher the helix content, the faster the coil to α-helix transition. The nature of the conformational change was examined by parallel measurements of the CD, the difference spectra, and the binding isotherm. As a result, it was concluded that, at a certain SDS concentration above 5 mmol/dm3, the native conformation of the protein is directly transformed to another conformation without passing through any intermediate one which may be caused when the SDS concentration is below the one mentioned above.
A Temperature-dependent Desorption Process of Molecular Ions in Field Desorption Mass Spectrometry
Authors: Shiraishi Hiroaki , Otsuki Akira , Fuwa Keiichiro
Published: July 2006

A temperature dependent desorption process of molecular ions operating in field desorption mass spectrometry (FDMS) was examined by means of measurements of desorption rates using cholesterol, stearic acid, and poly(oxyethylene) nonylphenyl ether. The desorption of ions formed under high electric field followed the first order kinetics. The desorption rate constants were measured at several emitter currents, and apparent activation energies for the desorption of molecular ions were calculated. A mass transfer process operating in FDMS is discussed.
Solvation Effect on the Complex Formation between o-Quinones and Metal Chlorides in Nonaqueous Media
Authors: Kataoka Kazuaki , Takagi Tatsuya , Sasaki Yoshio
Published: July 2006

The complex formation of o-quinones with metal chlorides was studied by means of spectrophotometry in CH3NO2 and CH3CN, where the metal chloride behaved as a nonelectrolyte. The results obtained in both solutions showed that the complex formation was obviously affected by the solvation of CH3CN to the metal chloride. The participation of CH3CN in the o-quinone–ZnCl2 complex was assumed as a result of comparing the Δνmax values, and the results obtained by NMR and spectrophotometry proved the coordination of two molecules of CH3CN to the complex. The values of Kc in CH3NO2 increased in the order of BiCl3<ZnCl2, whereas those in CH3CN were in the reverse order; this fact was ascribed to the number of the solvent molecules liberated in the complex formation. The conventional elimination of the solvation effect from the observed Kc was proposed in order to obtain a parameter of solvation-free Kc.
The Penetration of Lysine into the Monolayers of Lecithin from the Underlying Aqueous Solutions
Authors: Nakagaki Masayuki , Okamura Emiko
Published: July 2006

The surface pressure of the monolayers of dimyristoyl phosphatidylcholine (DMPC) on the lysine solutions was measured. The monolayer was more expanded on the solution than on pure water. The amount of lysine penetrating into the DMPC monolayer was calculated by means of a successive approximation. It was found that the amount of lysine penetrating increased with the increase in the concentration of the solution and with the decrease in the area per molecule of a DMPC monolayer, but it decreased with the further decrease in the area per molecule of DMPC. The average area per molecule of the monolayer consisting of lysine and DMPC was linearly related to the mole fraction of lysine. This linear relation indicates that partial molecular areas of both DMPC and lysine are independent of the amount of lysine in the monolayer. It is concluded that lysine and DMPC do not interact in the monolayer, although the monolayer of lysine and DMPC is formed as a result of the interaction between DMPC and lysine in a subsolution.
ESR Investigation of Alkali Metal Complexes of Galvinoxyl-labeled Benzo-15-crown-5 in Frozen Solution
Authors: Mukai Kazuo , Iida Nobuhito , Ishizu Kazuhiko
Published: July 2006

A stable galvinoxyl derivative (1) of benzo-15-crown-5 was prepared and the complex formation between the spin labeled crown ether 1 and the alkali metal and ammonium salts was studied by the ESR technique. Existence of the (2:1) complex of 1 with potassium, rubidium, and ammonium salts was confirmed by the observation of the triplet ESR spectra in ethanol rigid matrix at 77 K. Essentially the same g- and D-tensor values are observed for all the (2:1) complexes, indicating similar conformation of the ligand molecule 1. The zero-field splitting parameters (D and E) are calculated on the basis of the spin distribution of 1 and the assumed molecular structures for the (2:1) complex. By comparing the observed D and E parameters with the calculated ones, the structure of the (2:1) complex in ethanol rigid matrix is discussed. On the other hand, the sodium complexes of 1 show a slightly asymmetric single line, suggesting the (1:1) complex formation between 1 and the sodium salts. No anions (SCN−, Br−, and I−) have any appreciable effect on the ESR spectra of both the (2:1) and (1:1) complexes.
The Binding of Sodium Dodecyl Sulfate to Lysozyme in Aqueous Solutions. II. The Effect of Added NaCl
Authors: Fukushima Kohsuke , Murata Yoshio , Sugihara Gohsuke , Tanaka Mitsuru
Published: July 2006

The isotherms for the binding of sodium dodecyl sulfate (SDS) to lysozyme have been investigated as a function of the concentration of added NaCl at pH 5.8 and 25 °C by a potentiometric method utilizing a surfactant-selective electrode. The equilibrium surfactant concentration at which the binding begins to occur increases with increasing NaCl concentration. The equilibrium surfactant concentration giving the same binding number above 10, on the contrary, decreases with increasing NaCl concentration. Thermodynamic analysis shows that there takes place not only the exchange between chloride ion (Cl− ion) and dodecyl sulfate ion (DS− ion) but also the binding of DS− ion to the positively charged site unoccupied by Cl− ion. The addition of NaCl does not change the equilibrium SDS concentration at which the binding number begins to exceed 10. This equilibrium concentration is regarded as a characteristic one at which the affinity between lysozyme and SDS can be evaluated. The value of standard free energy change upon DS− ion binding and the number of Na+ ions bound to a DS− ion which forms a cluster on lysozyme were estimated from a thermodynamic equation based on the phase separation model.
Internal Heavy Atom Effect on the T1 States of Halogen-substituted Benzonitriles
Authors: Asahi Yoshinori , Hirota Noboru
Published: July 2006

The magnetic and decay properties of the ortho-, meta-, and para-substituted benzonitriles have been investigated and the nuclear charge and the position dependences of the internal heavy atom effects are examined in detail. From the single crystal EPR studies spin densities at the halogen atoms (ρH) are found to be in the order ρH(para)>ρH(ortho)>ρH(meta), but ρH(meta) is found to be much larger than that expected from the spin distribution in benzonitrile. The changes in the ZFS on going from the chloro-substituted molecules to the bromo-substituted molecules correlate with ρH and are explained in terms of the second order effect of the spin orbit mixing with 3σπ* (3πσ*) and (3nπ*) states. In the para-substituted molecules the relative increases of the Ty sublevel decay rates (ky) are much greater than those of the Tz sublevel decay rates (kz). The dependence of the average decay rate, 1/2(ky+kz) on the atomic spin orbit coupling constant (ζ), is considerably larger than expected from the ζ2 dependence. These results were discussed in connection with the closeness of the 3σπ* (3πσ*) states in bromine containing molecules. A correlation between the decay rate and ρH is observed and the factors affecting the position dependence are examined.
The Existence of an Unstable Limit Cycle in the Oregonator Model for the Belousov-Zhabotinskii Reaction
Authors: Sakanoue Shinji , Endo Mitsuo
Published: July 2006

With an Oregonator model for the mechanism of the Belousov-Zhabotinskii reaction (an oscillatory chemical system), the coexistence of a stable and an unstable limit cycle was confirmed from the results of computer simulations and the real unstable limit cycle was shown. The relation of the amplitude of the unstable limit cycles to the parameters f and p in Tyson’s equation was found.
Identification and Quantification of Poly(oxyethylene) Alkyl Ether Nonionic Surfactants in River Water at Trace Levels by Field Desorption Mass Spectrometry
Authors: Shiraishi Hiroaki , Otsuki Akira , Fuwa Keiichiro
Published: July 2006

Field desorption mass spectrometry (FDMS) was applied to the identification and quantification of poly(oxyethylene) alkyl ethers in natural waters at trace levels. The FD mass spectrum of poly(oxyethylene) (POE) derivatives, which produce (M+H)+, (M+cation)+, and cluster ions of the type (M1+M2+H)+, was mainly affected by emitter current, amount of sample loading, and the presence of metal salts. POE alkyl ethers were extracted from water by means of XAD-4 resin adsorption or solvent extraction under nitrogen bubbling, and determined by FDMS using tetradeuterioocta(oxyethylene) dodecyl ether as an internal standard. Sample sizes from 10−6 to 10−8 g are suitable for the quantification of POE alkyl ethers. The mole ratio of POE methyl-substituted undecyl ethers to POE dodecyl ethers was estimated by comparison with the FD mass spectra of the HPLC fractions of the extract.
Theoretical Signal-to-noise Ratio and Resolution in Ion-cyclotron-resonance Spectroscopy
Authors: Amano Chikara
Published: July 2006

A comparison is made theoretically of the signal-to-noise (S/N) ratio between the usual slow-sweep or the continuous-wave method and the pulsed Fourier-transform (FT) method in ion-cyclotron-resonance spectroscopy. Expressions of the maximum S/N ratio, as characterized by experimental parameters, are given in concrete form for both methods. Based on these expressions, it is shown that the FT method has a Fellgett S/N advantage when the resolution of a measurement is selected so as to be nearly equal to the true linewidth. A tradeoff between the S/N ratio and the resolution is discussed, and a possible reconciliation is suggested of inconsistent statements on a relation between the S/N and the resolution in the literature.
Reactions of the Bis(β-diketonato)platinum(II) Complexes with Various Nitrogen Bases
Authors: Okeya Seichi , Nakamura Yukio , Kawaguchi Shinichi
Published: July 2006

The bis(β-diketonato)platinum(II) complexes react with various nitrogen bases (L) to afford [Pt(β-dik)L2](β-dik), [Pt(β-dik-O)2L2], [PtL4](β-dik)2, and [Pt(β-dik)(β-dik-C)L] depending on the natures of the β-diketonate anions and L. All of these complexes are stable in solution, showing no sign of isomerization and dissociation of L. The platinum(II) complexes containing the O-unidentate β-diketonate ligand are much more stable than the corresponding palladium(II) complexes and [Pt(acac)(piperidine)2](acac) and [Pt(acac-O)2(piperidine)2] constitute a pair of linkage isomers. The complexes containing the 2,4-pentanedionate anion (acac) in the outer sphere readily undergo the H-D exchange of the methine proton of acac and the NH protons of coordinated amines with CDCl3.
Di- and Trinuclear Metal Complexes Containing a β-Diketonate Dianion as a Bridging Ligand
Authors: Otani Yukie , Nakamura Yukio , Kawaguchi Shinichi , Okeya Seichi , Hinomoto Tetsu
Published: July 2006

The dinuclear palladium(II) complexes [(PP)Pd(C1–C3-β-dik(2−)-O,O′)Pd(PP)](ClO4)2 containing a β-diketonate dianion as a bridging ligand were prepared by the reactions of the mononuclear complexes [Pd(β-dik(2−)-C1–C3)(PP)] with [Pd(PP)(H2O)2](ClO4)2. In the reactions of [Pd(etac(2−)-C1–C3)(dpe)] with [Pt(PPh3)2(H2O)2](ClO4)2 and [Ni(acac)2] in the 1:1 mole ratio, similar dinuclear complexes [(dpe)Pd(C1–C3-etac(2−)-O,O′)Pt(PPh3)2](ClO4)2 and [(dpe)Pd(C1–C3-etac(2−)-O,O′)Ni(acac)2] were produced, respectively, while the reactions of [Pd(β-dik(2−)-C1–C3)(PP)] with Ni(ClO4)2·6H2O and Mg(ClO4)2 in the 2:1 mole ratio afforded the trinuclear complexes [M{O,O′-β-dik(2−)-C1–C3Pd(PP)}2](ClO4)2 (M=Ni(II) and Mg(II)). The trihapto coordination to palladium(II) and O,O′-chelation to another metal atom of the β-diketonate dianion in these complexes were deduced mainly by IR and NMR spectroscopy.
The Reaction Involving One Electron Transfer in Key Step. NO2-Catalyzed Halogenation of Polycyclic Aromatic Compounds with Metal Halides
Authors: Sugiyama Takashi
Published: July 2006

In the co-existence of catalytic amount of nitrogen dioxide and oxygen, aluminum halide, titanium(IV) halide, and some other metal halides have been found to be highly selective and regiospecific halogenating agents for polycyclic aromatic compounds, including anthracene, pyrene, benz[a]anthracene, chrysene, phenanthrene, naphthalene, triphenylene, fluoranthene, benzo[b]thiophene, and dibenzothiophene.
Enzymatic Synthesis of Pyridine Nucleotides. Structural Property of Some New NAD-analogs, and Base Conditions Available for the Analog Formation
Authors: Tono-oka Shuichi
Published: July 2006

Some new β-NAD-analogs were prepared by a base-exchange reaction catalyzed by pig-brain NADase. The analogs produced from methyl 4-(methylamino)- and 4-(dimethylamino)nicotinates were proved to be 1,4-dihydropyridine form. On the contrary, the analog obtained from 4-(acetylamino)nicotinamide was shown to be a quaternary pyridinium form. Moreover, an unexpected analog of 1,4-dihydro-4-pyridinone form was given by 4-methoxynicotinamide. It was shown to be indispensable for the formation of NAD-analog that the ring nitrogen of pyridine bases concerned should at least be free from protonation around pH 7. Interestingly nicotinic acids with 4-amino, methylamino, and dimethylamino groups were found to be much more basic for the ring nitrogen atom than their respective methyl esters.
Oxidation of Lipids. II. Rate of Inhibition of Oxidation by α-Tocopherol and Hindered Phenols Measured by Chemiluminescence
Authors: Niki Etsuo , Tanimura Ritsuko , Kamiya Yoshio
Published: July 2006

The rate constants for the interactions of peroxyl radicals with α-tocopherol and hindered phenols were determined by chemiluminescence method. The thermal decomposition of di-t-butyl diperoxyoxalate in o-dichlorobenzene with and without ethylbenzene was found to give chemiluminescence under oxygen. 9,10-Dibromoanthracene was an effective activator. The addition of 1-tetralyl hydroperoxide gave chemiluminescence both in the presence and absence of oxygen, while the addition of t-butyl hydroperoxide suppressed the chemiluminescence almost completely even under oxygen. The addition of α-tocopherol and phenols also diminished the chemiluminescence, but after reaching the minimum intensity it again increased as the inhibitors were consumed. The rate constants for the scavenging of 1-phenylethylperoxyl radical by α-tocopherol, 2,4,6-tri-t-butylphenol and 2,6-di-t-butyl-4-methylphenol were obtained as 1.5×105, 1.2×104, and 1.0×104 M−1 s−1 (1 M=1 mol dm−3) respectively.
Attractive Interactions between Carbonyls and Groups Bearing Lone-pair Electrons in Triptycene Systems
Authors: Oki Michinori , Izumi Giichi , Yamamoto Gaku , Nakamura Nobuo
Published: July 2006

Compounds which carry a methoxyl or a chloro group in 1-position and a substituted carbonylmethyl group in 9-position of the triptycene system have been prepared to examine populations of rotamers by 1H NMR spectra. The methoxy compounds favored the ±sc conformations, whereas the ap conformations were relatively favored in the chloro compounds. The results indicate that there are attractive interactions between the carbonyls and a methoxyl or a chloro group and are discussed from the electron-accepting ability of the carbonyl group and the electron-donating ability of the methoxyl and the chloro groups. An aldehyde group was apparently less able to interact with electron-donors than a ketone. This apparent anomaly was discussed from the intramolecular dipolar interactions.
Photochemical Reactions of Aromatic Compounds. XXXVII. Solvent Effects on Fluorescence Quenching and Photoreactions of Naphthonitrile–Olefin and Furan Systems. Qualitative Consideration on Electronic Structures and Reactivities of Nonemissive Exciplexes
Authors: Pac Chyongjin , Yasuda Masahide , Shima Kensuke , Sakurai Hiroshi
Published: July 2006

Solvent effects on the fluorescence-quenching rate constants (γkc) as well as on the quantum yields (φ∞−A) of photoreactions have been investigated for the nonemissive exciplex systems in which 1- or 2-naphthonitrile is the electron acceptor whereas the donors are some enol ethers, a few simple alkenes, furan, 2-methylfuran, and ethyl phenyl ether. On the basis of the assumption of the solvent as a continuous dielectric medium, the relationships between electronic structures and reactivities of nonemissive exciplexes have been qualitatively estimated from the plots of logγkc and log[φ∞−A⁄(1−φ∞−A)] vs. (ε−1)⁄(2ε+1). In nonpolar and moderately polar aprotic solvents, the nonemissive exciplexes have low charge-transfer contributions but relatively high reactivities in the cycloaddition while much larger charge-transfer contributions are induced in more polar alcoholic solvents; the reactivities in the protic solvents decrease with the increase of solvent polarity. For some exciplexes, the occurrence of complete electron transfer in very polar solvents such as ethanol, methanol, and acetonitrile is strongly suggested from the product distributions. The possible availability of ET(30) or Z value as a scale of solvent polarity has been tested for the solvent effects on the processes from the nonemissive exciplexes.
Room-temperature Fluorine Addition to Fluoro-substituted Naphthalene Derivative Using Xenon Difluoride
Authors: Zajc Barbara , Zupan Marko
Published: July 2006

Room-temperature boron trifluoride catalyzed addition of fluorine to octafluoronaphthalene with xenon difluoride proceeds as 1,4- and 1,2-addition, giving decafluoro-1,4-dihydronaphthalene and decafluoro-1,2-dihydronaphthalene. Fluorine addition to 2-methoxy- and 2-ethoxyheptafluoronaphthalene gave only 1,4-adducts, while reaction with 2-isopropoxyheptafluoronaphthalene resulted in octafluoro-1,2-dihydronaphthalene-2-one and 6-isopropoxynonafluoro-1,4-dihydronaphthalene.
Study of Molecular Complexes by Refractometry
Authors: Singh Ram Adhar , Bhat Subray Narayan
Published: July 2006

The refractive index measurement technique is used to investigate molecular complex formation in liquid solutions and the association constants are determined directly. The association constants at 25 °C and heats of complexation for naphthalene–phenol, benzene–tetracyanoethylene, p-xylene–tetracyanoethylene, hexamethylbenzene–tetracyanoethylene, and triethylamine–iodine in cyclohexane are 8.2, 2.2, 8.6, 231, and 4620 dm3 mol−1 and 19.25, 11.30, 18.00, 32.21, and 51.46 kJ/mol, respectively. These values agree well with the literature data obtained by spectroscopic methods.
A Perturbative Study of Medium and Long Range Interactions between Some Characteristic Fragments of Lipid–Protein Systems
Authors: Raudino Antonio , Zuccarello Felice , Buemi Giuseppe , Rigano Carmelo
Published: July 2006

An intermolecular perturbation theory, originally presented by Murrell and developed by use of the LCAO approximation, was applied to a theoretical study on the interaction of a hydrogen-bonded dimer of formamide with ethane molecule or ammonium ion in order to simulate interaction between characteristic frameworks of proteins and lipids. Ethane has a preferential orientation parallel to the carbonyl bond supported by the prevailing charge-transfer contribution. Ammonium ion has preferential interaction regions dependent on the balance between the charge-transfer and coulombic forces along the NH···OC axis.
Adsorption of Electron Acceptors on Titania
Authors: Esumi Kunio , Meguro Kenjiro
Published: July 2006

Four electron acceptors with electron affinities ranging from 1.26 to 2.84 eV were adsorbed from acetonitrile solution on to a titania sample. On adsorption, radical anions were formed on the titania surface as a result of electron transfer to the acceptors from the surface of the titania. The concentration of radical anions thus formed decreased with the decreasing electron affinity of the acceptors; the decrease is steep between 1.26 and 1.77 eV. These results suggest that the limit of electron transfer from the titania surface to the acceptor ranges between 1.77 and 1.26 eV in the electron affinity of the acceptor.
Effect of the Chlorine Contents on the Lattice Constants of β-FeOOH
Authors: Ohyabu Matashige , Ujihira Yusuke
Published: July 2006

The lattice constants of β-FeOOH including chlorine and fluorine, were determined by X-ray diffractometry. The chlorine-content dependence of the lattice constants showed that chlorine ions are distributed at random, occupying certain sites of β-FeOOH.
The Cheletropic Addition of Dichlorocarbene to 2-Phenylsulfonyl-2-azabicyclo[3.2.1]octa-3,6-diene and Its 8-Substituted Derivatives
Authors: Inoue Hiroo , Tokisato Kazuhiko , Umano Katsumi
Published: July 2006

It was found that dichlorocarbene undergoes exo addition preferentially on the C3–C4 double bond of 2-phenylsulfonyl-2-azabicyclo[3.2.1]octa-3,6-diene and endo addition on that of 2-phenylsulfonyl-syn-8-benzoyloxy-2-azabicyclo[3.2.1]octa-3,6-diene.
The Reaction of 1-Methoxycarbonyl-2-imidazolidone with Phenylmagnesium Bromide
Authors: Matsumura Noboru , Matsukawa Kimihiro , Sakaguchi Yujiro , Inoue Hiroo
Published: July 2006

It is found that 1-methoxycarbonyl- or 1-phenoxycarbonyl-2-imidazolidone reacts with phenylmagnesium bromide to afford benzophenone and triphenylmethanol, together with 2-imidazolidone, by nucleophilic attack on the carbonyl group at the side chain.
Electrosynthesis of 2-Methyl-1,4-naphthoquinone (Vitamin K3) Directly from 2-Methyl-5,8-dihydro-1,4-naphthalenediol by a Four-electron Oxidation Procedure
Authors: Torii Sigeru , Tanaka Hideo , Nakane Shoji
Published: July 2006

A straightforward synthesis of Vitamin K3 was performed by electrolysis of 2-methyl-5,8-dihydro-1,4-naphthalenediol in a MeCN–t-BuOH (9/1)–LiClO4–(Pt or C electrodes) system. The use of perchlorate salts or tetrafluoroborate salts as supporting electrolytes in various electrolysis systems, such as AcOH–t-BuOH (9/1)–LiClO4–(Pt) and AcOEt–t-BuOH (9/1)–Bu4NClO4–(Pt), also provided good results, while the use of Et4NOTs in MeOH afforded 2-methyl-5,8-dihydro-1,4-naphthoquinone, preferentially.
Heterocylic Studies. Synthesis of 9-Hydroxybenzimidazo[2,1-b]benzothiazoles and Their Quaternary Derivatives
Authors: Soni R P , Saxena J P
Published: July 2006

A series of substituted 9-hydroxybenzimidazo[2,1-b]benzothiazoles has been synthesized. The position of phenolic hydroxyl group in these compounds has been ascertained on the basis of spectral data.
Static and Dynamic Properties of Quinoxalines in the Phosphorescent Triplet State from Optically Detected Magnetic Resonance
Authors: Suga Kazuhiko , Kinoshita Minoru
Published: July 2006

The static and dynamic properties of the phosphorescent triplet states of quinoxaline and 2,3-disubstituted derivatives in hexane have been studied at 1.4 K using the methods of optically detected magnetic resonance. In addition, the absorption and phosphorescence excitation spectra have also been measured to attain the information about the low lying excited states. A systematic comparison has been made for the purpose of examining the effect of substitution. A significant enhancement of the pumping rates for the y spin sublevel observed in the chlorinesubstituted derivatives is concluded to be due to the additional indirect process of intersystem crossing which occurs from S1 of n,π* to T1 passing through the intermediate triplet state of π,π*. A detailed discussion on the observed phosphorescence spectra originating from the three sublevels has achieved a satisfactory success in understanding the mechanisms responsible for the radiative decay processes. It is concluded that the mechanisms due to vibronic coupling with closely lying n,π* triplet states are of little importance in the systems studies here.
ESR Studies on the Free Radical Intermediates in the Photoreduction of Duroquinone in Alcohol Solutions
Authors: Noda Shoji , Sanehira Kiyoshi , Doba Takahisa , Yoshida Hiroshi
Published: July 2006

ESR measurements during photolysis of duroquinone (DQ) solutions in ethanol and 2-propanol have revealed the generation of both durosemiquinone anion (DQ−) and durosemiquinone radicals (DQH·). Correspondingly, alkoxyl radicals have been detected from the photolyzed solutions by the spin trapping-ESR technique, though the quantum yield of their formation is very low (10−3 for the ethanol solution). Main conclusions deduced from the present work are (1) that DQ\ewdot is generated through the one-electron reduction of DQ by α-hydroxyalkyl radical and through the photodissociation of (DQ-DQH2) complex, and (2) that DQH· is generated through the hydrogen abstraction of 3DQ* either from solvent alcohols or from photoproduct durohydroquinone (DQH2). The one-electron reduction in alcohol solution previously reported for p-benzoquinone is a minor pathway of chemical quenching of 3DQ*. The quantum yield of the DQH2 formation in an early period of photolysis of a dilute DQ in methanol, ethanol, and 2-propanol has been observed to be 0.12, 0.23, and 0.36 respectively. These values are discussed in terms of the mechanism of the quinone photorecduction.
Studies on 2-Aziridinecarboxylic Acid. V. Formation of Dehydroamino Acid Containing Peptides via the Isomerization by NaI of 2-Aziridinecarboxylic Acid Containing Peptides
Authors: Okawa Kenji , Nakajima Kiichiro , Tanaka Takumi , Neya Masahiro
Published: July 2006

The 2-aziridinecarboxylic acid residue in peptides was isomerized with NaI in an acetone solution into the corresponding dehydroalanine or dehydro-2-aminobutyric acid derivatives, but not into the corresponding 2-oxazoline derivatives.
The Nature of Oxygen Species Responsible for Propene Oxidation over V–Mo and V–Sn Oxides
Authors: Ono Takehiko , Kubokawa Yutaka
Published: July 2006

The rate of oxidation of C3H6 has been investigated over V–Mo oxides using 18O2(99%) tracer. The extent of participation of lattice oxygen in the oxidation increases with increasing MoO3 content, showing a maximum at V–Mo (33 mol% of MoO3) oxide. The rate of oxidation of C3H6 varies parallel to the extent of participation of lattice oxygen. A marked dependence of the rate of oxidation upon oxygen pressure observed with V–Mo(33) oxide is attributed to its high reducibility. Similar experiments have been carried out with V–Sn (94 mol% of SnO2) oxide. The rate of reduction of the oxide with C3H6 is about ten times smaller than that of the corresponding catalytic oxidation of C3H6, suggesting the participation of adsorbed oxygen in the oxidation. The results of 18O tracer experiments show participation of lattice oxygen in the oxidation. A mechanism which explains such conflicting results has been proposed.
The Decomposition of Water on the CO- or H2-reduced Indium Oxide
Authors: Otsuka Kiyoshi , Yasui Takao , Morikawa Akira
Published: July 2006

The reduction of In2O3 by H2 or CO and the reoxidation of the reduced oxide by water, accompanying the formation of hydrogen, have been investigated at ≥673 K. The reduction of In2O3 and the decomposition of water have been expressed by the forward reaction and the backward reaction respectively of this equation: In2O3(s)+xH2(g)\ightleftarrowsIn2O3−x(s)+xH2(g), where In2O3−x(s) is a mixture of indium metal and In2O3. Surface oxygen atoms of fresh In2O3 are easily removed by H2- or CO-reduction at 673 K, but they can not be reformed by oxidation with water. This explains the observation that the quantity of hydrogen produced in the oxidation step was somewhat deficient compared to that consumed by the reduction. The maximum rate of the decomposition of water is observed when the oxide has been reduced up to a 50% reduction-level. However, an excessive reduction (greater than 85%) results in a sharp decrease in the rate of the decomposition of water, probably because of the isolation of metallic indium from the host In2O3.
Chemistry of 1,3-Glycol Derivatives. IV. Mechanism of the Solvolyses of 2,4-Pentanediol Derivatives and the Reactions of the Proposed Intermediate Acetoxonium Ions with Carbanions and Hydride
Authors: Itoh Osamu , Iwakoshi Naoki , Saitoh Toshihide , Katano Hiroaki , Fujisawa Yoshiki , Hasegawa Yoshinori , Sugita Toshio , Ichikawa Katsuhiko
Published: July 2006

Regio- and stereochemical studies of the solvolyses of various kinds of 2,4-pentanediol derivatives, including 2-acetoxy-4-tosylates, cyclic orthoformates and orthoacetates, have been done and the previously proposed mechanism has been partially revised. The reactions of the proposed intermediate acetoxonium ions with carbanions and with a hydride ion have also been studied.
The Kinetics of Bromate-Cerium(III) and -Iron(II) Reactions
Authors: Yoshida Toshihisa , Ushiki Yataro
Published: July 2006

The bromate-cerium(III) and -iron(II) reactions in acidic media were examined with special reference to their induction periods and reaction rates. In the bromate-cerium(III) reaction, the induction period is followed by a burst of cerium(IV) formation and then a gradual formation of cerium(IV). In the bromate-iron(II) reaction, a slow decrease occurs only in acidic media, even without bromate, so it may differ from the decrease in the tris(1,10-phenanthroline)iron(II) concentration based on the oxidation by bromate. It was interpreted as the dissociation from [Fe(phen)3]2+ to [Fe(phen)2]2+ and phen. This is the induction period for iron(III) formation, which follows as the burst. The induction period and the rates of cerium(IV) or iron(III) formation can be interpreted on the basis of the mechanism for the Belousov oscillatory and the present redox reactions proposed by Noyes and his co-workers.
Spin Density Distribution and Energy Stabilization in the Cation Radicals of Multilayered Compounds
Authors: Ohya-Nishiguchi Hiroaki , Terahara Atsushi , Hirota Noboru , Sakata Yoshiteru , Misumi Soichi
Published: July 2006

The spin density distributions and the energy stabilizations in the polymer cation radicals (Rn+·) have been investigated by measuring the oxidation potentials (E1⁄2°) and the electron spin resonance (ESR) spectra of the cation radicals generated by the electrochemical oxidations of some multilayered compounds. E1⁄2° decreased monotonically as the number of layers increased. The spin densities on the aromatic rings have been estimated from the hyperfine coupling constants with the help of the McLachlan’s and INDO calculation. It was found that the spin density tends to localize in the central moieties in Rnn+·. The localization of the spin density and the energy stabilization are interpreted with a simple theoretical model of Rnn+·, which takes into accounts the repulsion integral (γ1) and resonance integral (ζ) between the nearest neighbor molecules. The comparison with the experimental data has lead to the numerical estimates of γ1=0.1 eV and ζ=0.4 eV.
Nanosecond Laser Flash Photolysis of 1-Anilinonaphthalene
Authors: Nakamura Hiroki , Tanaka Jiro , Nakashima Nobuaki , Yoshihara Keitaro
Published: July 2006

The photoionization mechanism of 1-anilinonaphthalene (1-AN) was investigated by a nanosecond laser flash photolysis and the result was compared with that of 8-anilino-1-naphthalenesulfonate (ANS). The photoionization of 1-AN in polar solvent is shown to occur through a biphotonic process via a triplet state; the mechanism is different from those of ANS, in which an intermediate of a charge transfer to solvent (CTTS) state was observed. Thus the major deactivation process of the lowest excited singlet state is an intersystem crossing in 1-AN, while it is a transition to the CTTS state in ANS which might be stabilized by the sulfonato group.
Flash Pyrolysis of Selenides. Syntheses of Bibenzyls, Olefins, and Related Compounds
Authors: Higuchi Hiroyuki , Otsubo Tetsuo , Ogura Fumio , Yamaguchi Hachiro , Sakata Yoshiteru , Misumi Soichi
Published: July 2006

Pyrolyses of a series of selenides and diselenides were studied. Selenides and diselenides bound with an active methylene group like benzyl gave a variety of substituted bibenzyls and related ethane derivatives in high yields. Other diselenides were easily caused to cleave to give various aromatic and aliphatic olefins in good yields together with elemental selenium. Lepidopterene, [2.2]paracyclophane, and benzocyclobutene were prepared by thermal cleavage of their corresponding phenylselenomethyl-substituted compounds as an application of the pyrolysis concerned.
Phase Equilibria in the Gd2O3–V2O3–V2O5 System at 1200 °C
Authors: Kitayama Kenzo , Katsura Takashi
Published: July 2006

The phase equilibria in the Gd2O3–V2O3–V2O5 system are studied at 1200 °C by changing the oxygen partial pressure from −0.68(air) to −12.50 in terms of logPO2. In this system, Gd2O3, GdVO4, GdVO3, 0.81Gd2O3. 0.19V2O5, V2O3, V3O5, V4O7, V5O9, V6O11, V7O13, and VO2 are stable. GdVO4 and 0.81Gd2O3·0.19V2O5 have nonstoichiometric compositions. The crystallographic properties of the latter are determined with reference to the indices of a certain compound, 4Tm2O3·V2O5. On the basis of the phase equilibria, the Gibbs free energy of these two reactions: 31/50 Gd2O3+19⁄50 GdVO3+19⁄100 O2= Gd1.62V0.38O3.38 and: GdVO3+1⁄2 O2= GdVO4 are determined to be 57.0 and 127.8 kJ respectively.
Separation and Quantification for Various Phosphorus Oxoacids by Isotachophoresis
Authors: Yagi Takao , Kojima Kayoko , Nariai Hiroyuki , Motooka Itaru
Published: July 2006

The analytical procedure for the separation and quantification of various phosphorus oxoacids was investigated by the capillary type isotachophoresis. The various phosphorus oxoacids, such as linear-, cyclic-, and lower phosphorus oxoacids, were separated at pH 5.5 with a 0.01 mol dm−3 hydrochloric acid–histidine–0.1% triton X-100 mixture as the leading electrolyte and a 0.01 mol dm−3 hexanoic acid as the terminating electrolyte. The PU value increased in the order of P3m<P4m<P3<P2<\overset1P<\overset3P<P1. The calibration curves for the various phosphorus oxoacids were linear in the range of 0.5–3.5 μg as phosphorus oxoacids. Coefficients of variation for the measured phosphorus oxoacids were less than 2% except for P3. Separation times were approximately 15 min. This procedure was applied to the ground phoshates.
Synthesis of [3.3](1,3)Ferrocenophane and Its Derivatives
Authors: Kasahara Akira , Izumi Taeko , Yoshida Yoshio , Shimizu Iwao
Published: July 2006

[3.3](1,3)Ferrocenophane-1,15-diene-3,14-dione was synthesized via the base-catalyzed condensation of 1,3-ferrocenedicarbaldehyde with 1,3-diacetylferrocene utilizing the high dilution technique. The reduction of the compound with LiAlH4–AlCl3 and the subsequent catalytic hydrogenation led to the formation of [3.3](1,3)ferrocenophane. The transannular π-electronic interactions between the two ferrocene moieties in these compounds were examined on the basis of NMR and electronic spectra.
2-Methylamino-4,5-imidazoledione. A Revised Structure for Creatone, Methylparabanic Acid Imide, and (3-Methylguanidino)glyoxylic Acid
Authors: Yamamoto Hiroshi , Pfleiderer Wolfgang
Published: July 2006

The previous structures presented for the Hg(OAc)2 oxidation product of creatine, the condensation product of methylguanidine and diethyl oxalate, and the peracid oxidation product of 1-methyl-2-amino-dihydropyrimidines are all replaced by a revised formulation, 2-methylamino-1H-imidazole-4,5-dione on the basis of the pKa values (0.62 and 7.87) and the spectra. The equilibria between this thermodynamically controlled product and the previous formulations are discussed.
Addition Reaction of Carboxylic Anhydrides to the Carbon-Nitrogen Double Bond of Unsubstituted Cyclic Imidates
Authors: Kobayashi Shiro , Isobe Michihisa , Saegusa Takeo
Published: July 2006

Acyclic and cyclic (SAn and GAn) carboxylic anhydrides were added at room temperature to the C=N bond of unsubstituted cyclic imidates of 2-oxazoline (OZO) and 5,6-dihydro-4H-1,3-oxazine (OZI) to give addition products quantitatively. In contrast to these findings, the reactions of acetyl halides with OZO and OZI yielded ringopened products and the reactions of carboxylic anhydrides with 2-benzyl-2-oxazoline (BzOZO) afforded also the ring-opened products. The bicyclic addition product of OZO with SAn is equilibrated with a mixture of starting materials. The stereochemistry of addition products having a six-membered ring system is discussed.