bluuebunny/crossref_metadata_2025_split 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

Abstract
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

Abstract
(±)-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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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&lt;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

Abstract
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

Abstract
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

Abstract
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

Abstract
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)&gt;ρH(ortho)&gt;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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.