bluuebunny/crossref_metadata_2025 huggingface dataset:
Circular Dichroism and Stereochemistry of Tetranuclear Cobalt(III) Complexes of Hexol Type. III. The meso-2,3-Butanediamine, (R)-1,2-Propanediamine, and (R,R)-1,2-Cyclohexanediamine Complexes
Authors: Kudo Tomikatsu , Shimura Yoichi
Published: July 2006

Eight, six, and four optical isomers of diamine hexols [Co{(OH)2Co(diarnine)2}3]6+ containing meso-2,3-butanediamine, (R)-1,2-propanediamine, and (R,R)-1,2-cyclohexanediamine, respectively, were separated by column chromatography. The absorption and CD (circular dichroism) spectra were measured in the visible and ultraviolet regions in 0.01 mol dm−3 HCl, the absolute configurations being determined mainly on the basis of the CD spectra. Assuming that the configurational chiralities are identical to those of the corresponding ethylene-diamine hexol isomers, it has been established that the lel and ob orientations of the (R)-diamine ligand show different vicinal CD curves due to the asymmetric carbon atom in the ligand.
Synthesis of (±)-Dihydrofomannosin Acetate
Authors: Kosugi Hiroshi , Uda Hisashi
Published: July 2006

The synthesis of (±)-dihydrofomannosin acetate [5-acetoxymethyl-1-(4,4-dimethyl-2-oxocyclopentyl)-3-oxabicyclo[4.2.0]oct-5-en-4-one] is described. Photocycloaddition of 4-(2-acetoxy-4,4-dimethylcyclopentyl)-2(5H)-furanone to ethylene gave 5-(2-acetoxy-4,4-dimethylcyclopentyl)-3-oxabicyclo[3.2.0]heptan-2-one, which was converted into ethyl [2-acetoxymethyl-2-(2-acetoxy-4,4-dimethylcyclopentyl)cyclobutyl]glyoxylate by the reaction with 2-methylthio-1,3-dithiane, followed by acetylation and ethanolysis. Introduction of an additional one carbon unit to the glyoxylate was accomplished by the Wittig reaction, and the subsequent hydrolysis and lactonization afforded 1-(2-hydroxy-4,4-dimethylcyclopentyl)-5-methylene-3-oxabicyclo[4.2.0]octan-4-one, which was transformed into 5-acetoxymethyl-5-hydroxy-1-[4,4-dimethyl-2-(tetrahydropyranyloxy)cyclopentyl]-3-oxabicyclo[4.2.0]-octan-4-one. Mesylation followed by elimination and oxidation led to (±)-dihydrofomannosin acetate.
Effects of Sodium Tetraborate as an Additive on the Reaction of α-Alumina with Sodium Carbonate
Authors: Chang Byong-Tae , Oh Jae-Gun , Om Suk-Ja
Published: July 2006

Effects of sodium tetraborate as an additive in the reaction of α-alumina with molten sodium carbonate have been studied mainly in a N2 atmosphere. Addition of sodium tetraborate accelerates the reaction, the α-alumina reacted increasing from 31.7% to 99.3% by addition of sodium tetraborate corresponding to the initial B2O3/Na2O molar ratio of only 1/15 under the other same conditions. By means of the Jander equation the activation energy was found to be 53 kcal/mol for the α-Al2O3–Na2CO3–Na2B4O7, system, which was lower by 10 kcal/mol than that for the α-Al2O3–Na2CO3 system. X-Ray diffraction and thermal data were analyzed in relation to the phase equilibrium of the melt.
The Chromatographic Concentration of Mercury in Sea Water with 2-Mercaptobenzothiazole Supported on Silica Gel
Authors: Terada Kikuo , Morimoto Kumiko , Kiba Toshiyasu
Published: July 2006

A solid chelating material, 2-mercaptobenzothiazole supported on silica gel (MBT-SG), was prepared and used for the preconcentration of inorganic and organic mercury compounds from a sea-water sample. The chelating capacity of the material was 12 μeq. Hg/g. The mercury (II) ion, the methylmercury ion, and the ethylmercury ion were quantitatively retained on the MBT-SG at pH values of 1.0, 5.0, and 4.0 respectively from an aqueous solution, and at pH values of 4.0, 4.5, and 5.0 respectively from a sea-water. A column packed with the material provided a quantitative recovery of these ions from a sea-water sample at a high flow rate (1–3 1 h−1). Mercury was eluted by the use of a acetone–hydrochloric acid mixture (25: 1) or a 1% thiourea solution in 0.1 mol dm−3hydrochloric acid. The latter effluent was submitted atomic-absorption spectrometry after reductive vaporization for the determination of mercury.
Binuclear Metal Complexes. XXXI. Synthesis and Magnetic Property of Binuclear Manganese(III) Complexes with 3-Salicylideneamino-1-propanol and Its Homologues
Authors: Torihara Naoyuki , Mikuriya Masahiro , Okawa Hisashi , Kida Sigeo
Published: July 2006

Binuclear manganese(III) complexes with 3-salicylideneamino-1-propanol and its homologues, MnL(ac) and MnLXH2O (L=Schiff base dianion; ac=acetate ion; X−=Cl−, Br−, N3−), were synthesized. It was shown that manganese(III) ions were bridged by the deprotonated alcoholic oxygen of the Schiff base in the equatorial plane and coordinated by bidentate acetate ion or X− and H2O groups in apical positions to form six-coordination. Cryomagnetic measurements indicated that an antiferromagnetic spin-exchange interaction operates between a pair of manganese(III) ions; exchange integral being evaluated at −13.5–−20.4 cm−1.
The Extraction of Several Anions by Methyltrioctylammonium into Various Solvents
Authors: Inoue Yasushi , Tochiyama Osamu
Published: July 2006

The back extraction of methyltrioctylammonium chloride (MTOACl) from ten kinds of organic solvents was investigated as a function of the MTOACl concentration. The chemical species of the ammonium salt in the organic phase were found to be in the form of dissociated ions, of ion pairs, or of dimeric ion pairs, according to the dielectric constant of the solvent. MTOACl was better extracted into more polar and acidic solvents, such as nitrobenzene, 3-methyl-1-butanol, and chloroform. The selectivity coefficients (KX/Cl) of MTOA for the exchange of Br−, I−, ClO4−, vs. Cl− were obtained from the study of the distribution of several organic color reagents; they were found to increase with the anion size, irrespective of the organic solvent used. For all but acidic solvents, the values of KX/Cl were similar to each other. Such acidic solvents as 3-methyl-1-butanol and chloroform, however, reduced the selectivity of the extraction for anions.
The Synthesis of Tedanin and Its Isomer, 3-Hydroxy-2,3-didehydro-β,φ-caroten-4-one
Authors: Yasuhara Mitsuki , Inanaga Kazuko , Kumae Takashi , Brahmana Hemat Rysona , Okukado Nobuhisa , Yamaguchi Masaru
Published: July 2006

The structure, 3-hydroxy-2,3-didehydro-β,χ-caroten-4-one, assigned to tedanin, the main carotenoid pigment of the marine sponge “Tedania digitata (O. Schmidt),” has been confirmed by total synthesis starting with β,χ-carotene. An isomer, 3-hydroxy-2,3-didehydro-β,φ-caroten-4-one, was also synthesized from β,φ-carotene.
Stereochemistry of Nucleophilic Addition Reactions. VIII. Preparation of 1,5-Anhydro-4,6-O-benzylidene-2,3-dideoxy-3-nitro-d-erytho-hex-2-enitol and Its Reactions with Some Nucleophiles
Authors: Sakakibara Tohru , Nomura Yutaka , Sudoh Rokuro
Published: July 2006

The title compound was synthesized from 1,5-anhydro-d-glucitol via nitromethane cyclization. The reduction of the compound with sodium borodeuteride afforded a mixture of saturated nitro compounds having an axial and equatorial deuterium atom at C-2 in an approximate ratio of 2:1. On the other hand, the reaction with hydrogen cyanide gave predominantly the adduct with the manno configuration, together with small amounts of a cyano olefin. The reaction with hydrazoic acid yielded addition products with the gluco and manno configurations; the ratio was strongly affected by the solvent used.
The Reactions of (1-Halo-1-alkenyl)dialkylboranes with Lead(IV) Acetate or (Diacetoxyiodo)benzene. A Stereoselective Synthesis of 1-Halo-1,2-dialkylethylenes
Authors: Masuda Yuzuru , Arase Akira , Suzuki Akira
Published: July 2006

The reaction of (1-halo-1-alkenyl)dialkylboranes with lead(IV) acetate or (diacetoxyiodo)benzene was studied. (1-Bromo-1-alkenyl)dialkylboranes gave 1-bromo-1,2-dialkylethylenes. When alkyl groups on the boron atom of vinylboranes were bulky or the reaction temperatures were low, Z-isomers were afforded, whereas when alkyl groups on the boron atom were small or the reaction temperatures were relatively high, E-isomers were afforded as the main products. (1-Chloro-1-alkenyl)dialkylboranes gave (Z)-1-chloro-1,2-dialkylethyienes regardless of the reaction conditions. (1-Iodo-1-alkenyl)dialkylboranes failed to give satisfactory yields of 1-iodo-1,2-dialkylethylenes.
Enolate Anions. II. Substituent Effects of Sodium Ethyl Phenylacetates in DMSO
Authors: Kiyooka Syun-ichi , Ueda Yoshinobu , Suzuki Kojiro
Published: July 2006

The UV-visible, IR, and 1H-NMR spectra of the sodium enolates of ethyl phenylacetates (substituents; p-CH3O, p-CH3, m-CH3, H, p-Cl, p-CH3CO, m-CH3CO, p-COOC2H5, p-CN, and p-NO2) in DMSO were measured at room temperature. The derivatives with electron-attracting groups at the para position exhibit their absorption maxima with ε>104 in visible regions above 400 nm. The visible spectra suggest the presence of a resonance between their electron-attracting groups at the para position and the enolate anion parts through the benzene ring. The carbonyl-stretching vibrations of the enolates in the IR spectra and the chemical shifts of the residual methine proton of the enolates in the 1H-NMR spectra can be well explained by using the substituent constants, σ and σ−. The ρ values of the meta and para lines are extremely different. In the case of the p-NO2 derivative, the 1H-NMR spectra of the benzene-ring protons indicate that the free rotation of the partially double bond between the benzene ring and the enolate-anion part is fixed at room temperature.
The Reaction of Alkenylboranes with Palladium Acetate. Stereoselective Synthesis of Olefinic Derivatives
Authors: Yatagai Hidetaka
Published: July 2006

The reactions of alkenylboranes with palladium acetate were investigated. Alkenyldialkylboranes, derived from terminal alkynes, underwent intramolecular migration reaction in the presence of an equimolar amount of palladium acetate and triethylamine to give (E)-olefins. On the other hand, under the same conditions as above or even in the presence of catalytic amounts of palladium acetate, alkenyldialkylboranes derived from internal alkynes underwent protonolysis reaction to produce (Z)-olefins. An alkenylpalladium intermediate which was presumably involved in the latter reaction was trapped by allylic chloride to give 1,4-dienes.
Photochemical Reactions of Dicyanobenzenes with Aliphatic Amines
Authors: Ohashi Mamoru , Miyake Kentaro , Tsujimoto Kazuo
Published: July 2006

Upon irradiation, p-dicyanobenzene reacted with primary, secondary, and tertiary aliphatic amines to give substitution products in which one of the cyano groups was replaced by the amine at α-CH position or by an alkyl group of the amine. o-Dicyanobenzene reacted similarly, but the meta-isomer did not react under similar conditions. The rates of the fluorescence quenching of p-dicyanobenzene with the amines are close to the diffusioncontrolled rate, but are somewhat dependent on the ionization potentials of the amines. When the substitution product was irradiated, the corresponding alkylation product was obtained. The mechanisms of these reactions have been investigated by the use of such proton donors as MeOH(MeOD); on the basis of those investigations, new photochemical reactions involving charge-transfer, followed by proton-transfer and then addition-elimination, are proposed, as well as a new type of photo-induced Birch reduction.
Abnormal Nazarov Reaction. A New Synthetic Approach to 2,3-Disubstituted 2-Cyclopentenones
Authors: Hirano Shigeo , Takagi Seiji , Hiyama Tamejiro , Nozaki Hitosi
Published: July 2006

Acid-catalyzed reaction of β,β′-disubstituted cross conjugated dienones or the corresponding ethylene acetals gives mainly 2,3-disubstituted 2-cyclopentenones in stead of the simple Nazarov cyclization products, 3,4-disubstituted 2-cyclopentenones. This transformation is explained in terms of electrocyclic ring-closure, addition of hydroxylic solvent(s), tautomerization of the resulting 2-hydroxycyclopentanone intermediates, followed by solvolysis and isomerization. Based on this working hypothesis a new route to jasmonoids is disclosed which involves acid-treatment of the acyloin disilyl ethers derived from substituted glutarates.
Nucleophilic Reactions of Hexafluoro-1,2-epoxypropane with 1,2-Bifunctional Ethanes
Authors: Kawa Hajimu , Hamouda Hamdy A , Ishikawa Nobuo
Published: July 2006

Reactions between hexafluoro-1,2-epoxypropane and 1,2-bifunctional ethanes were studied. Ethylenediamine, 2-aminoethanol and 2-aminoethanethiol gave corresponding N- and O-pentafluoropropionylated products, while ethylene glycol, 2-mercaptoethanol, and 1,2-ethanedithiol afforded ring closed products, such as 1,4-dioxanone, 1,4-oxathianone, and 1,4-dithianone compounds.
The Thermal Stability of Metal Cation–TCNQ Anion Radical Salts
Authors: Kishimoto Yoshio , Shimotsuma Wataru
Published: July 2006

To study the thermal stability of several metal cation–TCNQ salts (mainly alkali metal salts), the variation in the electrical resistivity and the characteristics of the chemical degradations by heating were measured. Most metal–TNCQ salts do not melt and are not sublimated, but have decomposition points at about 320 °C. Na(TCNQ) has a stable resistivity, even after heating for 500 hours at 200 °C, and is the most stable among the metal–TCNQ salts tested. Metal–TCNQ salts are gradually damaged from the surfaces of the crystalline powders by heating, and the TCNQ, molecule is oxidized, thus losing CN groups. The crystallization process of the TCNQ salts has a great influence upon their thermal stabilities. In the complex salt Cs2(TCNQ)3, the application of d.c. voltage gives rise to the polarization current at a temperature near 200 °C, and the TCNQ molecules tend to migrate in the electric field.
Temperature Dependence of Structural Propensity of 1-Butanol in Water
Authors: Murthy Neriyanuri Manohara , Subrahmanyam Saraswatula Venkata
Published: July 2006

The temperature dependence of structural propensity of 1-butanol has been studied by investigating its effect on the temperature of sound velocity maximum (TVM) in aqueous mixtures of glycerol and pyridine. The structural contribution to the shift in TVM of binary solution, [ΔTstr]exp was found to be positive at low concentrations of 1-butanol for aqueous pyridine solutions whose TVM are 37.6 °C and 23.7 °C. For aqueous glycerol solutions whose TVM is 43.3 °C, [ΔTstr]exp values, in the entire concentration range of 1-butanol studied, are found to be negative. The results indicate that below 40 °C 1-butanol behaves as a structure promoter while above 40 °C it behaves as a structure breaker.
Macroscopic Viscosity and Dielectric Relaxation Process of Ethyl and Butyl Acetates
Authors: Saxena Sudhir Kumar , Shukla Jagdish Prasad , Saxena Mahesh Chandra
Published: July 2006

Dielectric constants and losses have been measured at 9.8 GHz microwave frequency for ethyl and butyl acetates in benzene and benzene–paraffin oil mixtures at 18 °C. The data obtained has been analysed in terms of the two relaxation times τ(1) and τ2 using Higasi, Koga, and Nakamura method and their dependence on the viscosity has been examined. Since the observed values of τ(1)and τ(2) are significantly different, the systems studied represent two Debye type dispersions. It has been found that the relaxation behaviour giving rise to τ(1) in both the ester molecules is not effected to any appreciable extent by the increased macroscopic viscosity. The dielectric relaxation time τ(2) associated with the molecular process lengthens with the increasing macroscopic viscosity of the medium.
The Back-extraction Behavior of Chelate Compounds. III. The Extraction and the Back-extraction of the Metal (II) Diethyldithiocarbamates
Authors: Honjo Takaharu , Imura Hisanori
Published: July 2006

The behavior of trace amounts of cadmium(II), cobalt(II), copper(II), iron(II), mercury(II), manganese(II), nickel(II), lead(II), and zinc(II) in backextraction has been examined in order to establish the basic conditions for the separation of metals as their diethyldithiocarbamates by back-extraction.
Reaction of Bis[1-(2-pyridylazo)-2-naphtholato]cobalt(III) Chloride, [CoIII(pan)2]Cl, with Hyperoxide in Dimethyl Sulfoxide
Authors: Mochizuki Katsura , Imamura Taira , Fujimoto Masatoshi
Published: July 2006

The complex [CoIII(pan)2]+ was found to react in DMSO with hyperoxide, O2−, to give a bivalent cobalt complex [CoII(pan)2]0. The oxidation of [CoII(pan)2]0 to [CoIII(pan)2]+ by oxygen did not proceed in DMSO in the absence of water and/or H+. The standardization of O2− in DMSO were also described.
The Reductive Coupling of Organic Halide Using Hydrazine and a Palladium Amalgam Catalyst. I. The Preparation of Biaryls
Authors: Nakajima Riichiro , Shintani Yuji , Hara Tadashi
Published: July 2006

Iodoarenes could be converted to the corresponding biaryls in high yields by the use of a catalytic amount of a palladium amalgam in place of a palladium–calcium carbonate catalyst in Busch’s reaction. The 2,3′-isomer content in the bitolyls obtained by the homo-coupling of o-iodotoluene was 15% when palladium was used, while it was 1% when a palladium amalgam was used, and the latter was re-usable. The present method is further applicable to some iodoalkanes.
Reactions of Thionitrites or Thionitrates with Carbanions
Authors: Shinhama Koichi , Kim Yong Hae , Oae Shigeru
Published: July 2006

Reaction of several thionitrites (RSNO) or thionitrates (RSNO2) with carbanions such as Grignard reagents, alkyllithium, or the carbanion of diethyl malonate gave C-alkylthio derivatives such as sulfides or diethyl (alkylthio)malonates.
Synthesis Using Allylidenedihydropyridines. VIII. Facile Preparation of 2-Alkylthio-3-vinylpyrazolo[1,5-a]pyridines
Authors: Kakehi Akikazu , Ito Suketaka , Watanabe Kozo
Published: July 2006

Reactions of 1-[bis(alkylthio)methyleneamino]-2-methylpyridinium iodides with activated ethoxymethylene compounds in the presence of alkali gave the corresponding 1-[bis(alkylthio)methyleneamino]-2-allylidene-1,2-dihydropyridines in considerable yields, and their thermolyses in benzene afforded 2-alkylthio-3-vinylpyrazolo[1,5-a]pyridine derivatives.
Diazoalkane Complexes of Molybdenum
Authors: Mizobe Yasushi , Uchida Yasuzo , Hidai Masanobu
Published: July 2006

The hydrazido(2-) complexes [MoX2(NNH2)(PMe2Ph)3] (X=Cl or Br) derived from bis(dinitrogen) complex and HX react with aldehydes or ketones to give a series of diazoalkane complexes [MoX2(\underset←=N–N=CRR′)(PMe2Ph)3].
Synthesis of Dihydrosphingosine
Authors: Saitoh Yutaka , Moriyama Yoshihiko , Hirota Hiroshi , Takahashi Takeyoshi
Published: July 2006

A conversion of (S)-3-acetoxy-2-phthalimidopropanal into dihydrosphingosine is described.
Raman Study of Aqueous Solutions of Tetraalkylammonium and Bis(tetraalkylammonio) Electrolytes
Authors: Nomura Hiroyasu , Tsukamoto Yoshiaki , Verrall Ronald Ernest , Miyahara Yutaka
Published: July 2006

The Raman and infrared spectra of 1,4-bis(triethylammonio)butane dibromide (J4), 1,10-bis(triethylammonio)decane dibromide (J10), and tetraethylammonium bromide (TEABr) were measured in the solid and dissolved states. The Raman spectra of these salts in the solid and solution states were roughly similar to those of normal paraffins having the same number of skeletal atoms, but some minor differences were found. It was confirmed that molecular conformations of these ions in the solid and solution states are somewhat similar and take the all-trans form, but in main chain of J4 and J10, the gauche form is also observed. In addition, the effects of hydrophobic interaction of these salts in aqueous solution are discussed by comparison of the Raman spectra of OH stretching vibration region of water.
The Gibbs Adsorption Equation for Aqueous Solutions Containing a Weak Base
Authors: Ikeda Shoichi , Ozeki Sumio
Published: July 2006

The Gibbs adsorption isotherm for quaternary systems of water, weak base, HCl or NaOH, and NaCl including a vapor-solution interface is expressed in terms of variations of chemical potentials of neutral components added to make up the solution. Four systems are treated, and the Gibbs convention is introduced in such a way that the surface excess of added water is zero and the surface excesses of solute components are defined. Assuming that the activity coefficients of solute components are unity, the lowering of surface tension is given in terms of variations of total molar concentrations of weak base or its hydrochloride, HCl or NaOH, and NaCl, or of pH of the solution.
Solvent Effect on the Partition Equilibrium of Normal Aliphatic β-Diketones between Heptane and Water–Dimethyl Sulfoxide Mixed Solvents. The Extended McDevit-Long Approach
Authors: Watarai Hitoshi , Suzuki Nobuo
Published: July 2006

The partition equilibria of 7 normal aliphatic (C5-C9) β-diketones were investigated in the two-phase systems of heptane/water–dimethyl sulfoxide (DMSO) mixed solvents at 25 °C. The partition coefficients, P, of the keto and enol forms of the β-diketones were determined, and the linear correlations between logP and the number of carbon atoms in the n-alkyl groups were observed. In general, an increase in the mole fraction of DMSO, Xs, in the mixed-solvent phase caused a lowering of the partition coefficient, while with smaller β-diketones, distinct maxima were observed at Xs\simeq0.2. The solvent effect of the mixed-solvent phase was interpreted on the basis of the extended McDevit-Long theory previously proposed by the present authors.
Molecular Dynamical Studies on Nitrobenzene in Solutions of Tetraethyl and Tetrabutylammonium Bromides
Authors: Nomura Hiroyasu , Tsukamoto Yoshiaki , Miyahara Yutaka
Published: July 2006

The concentration and temperature dependences of the reorientational correlation times of nitrobenzene in solutions of tetraethyl (TEABr) and tetrabutylammonium bromides(TBuABr) have been determined by Raman line shape analysis. Pure liquid nitrobenzene was evaluated for comparison. The reorientational correlation times of nitrobenzene in solutions decreased with increasing concentration of the salts and the apparent activation enthalpy of τor of nitrobenzene in solutions was larger than in that pure nitrobenzene. From the experimental results, the solution structure of TEABr and TBuABr in nitrobenzene are discussed.
Boron Isotope Separation by Ion Exchange Chromatography Using Weakly Basic Anion Exchange Resin
Authors: Sakuma Yoichi , Aida Masao , Okamoto Makoto , Kakihana Hidetake
Published: July 2006

Isotopic plateau displacement chromatography, a useful method for isotope separation is presented. The boric acid band formed in a column of weakly basic anion exchange resin Diaion WA21 can be eluted with pure water. In order to obtain good accumulation of the isotope effect, a series of experiments with different migration length were carried out. The boron-10 enriched part of the boric acid absorbed band was always preceded by the isotopic plateau part, in which the atomic fraction of boron-10 was maintained at its original value. The atomic fraction of boron-10 at the end of the chromatogram increased with migration length, and in the case of 256-m migration, boron-10 was enriched from its original atomic fraction of 19.84 to 91.00%, the separation factor S being constant irrespective of migration length: S=1.0100±0.0005.
The Light-driven Electron Transfer Reaction of Chlorophyll a–Lumiflavin in Micelle
Authors: Yoshimura Akio , Kato Shunji
Published: July 2006

The light-driven electron transfer reaction for the system of chlorophyll a–lumiflavin in micelles was studied by means of flash photolysis. In the sodium dodecyl sulfate micellar solution, the chlorophyll a cation radical appeared on the flash excitation and then decayed by means of a second-order process under aerated conditions as well as under deaerated conditions (the radical was not observed in dioxane). The decay parameter in the aerated solution was smaller than that in the deaerated solution by a factor of twenty. The difference in the decay parameter was explained in terms of the function of the surface charge of micelles. In the deaerated solution, the chlorophyll a cation radical decays by means of a reaction with lumiflavin semiquinone of no charge; in the aerated solution, however, it decays by means of a reaction with the O2\ewdot produced by the electron transfer from lumiflavin semiquinone to oxygen. The latter decay reaction is retarded by the charge on the micelles.
Sound Velocity, Density, and Compressibility in Solutions of Hexamethylphosphoric Triamide in H2O and D2O
Authors: Lyashchenko A K , Goncharov V S , Iijima Toshiro , Uedaira Hisashi , Komiyama Jiro
Published: July 2006

Sound velocity and density measurements for H2O and D2O solutions of hexamethylphosphoric triamide (HMPT), [(CH3)2N]3PO at 25 °C have been carried out. The concentration dependence of the molar volumes and adiabatic compressibilities calculated therefrom are interpreted in terms of the water structure. The differences found between the H2O and D2O solutions are similarly explained.
Photooxidation of 2-Hydroxy Acids by Copper(II) Species in Aqueous Solution
Authors: Matsushima Ryoka , Ichikawa Yoshinori , Kuwabara Katsuyuki
Published: July 2006

Ultraviolet irradiation of aqueous lactic, glycolic, or 2-hydroxybutanoic acid in the presence of copper(II) leads to photoredox reaction to give corresponding α-keto acid, aldehyde with evolution of carbon dioxide, and the precipitate of copper(I). The mole ratio of the carbonyl products to the consumption of copper(II) is close to 0.5. Oxidative decarboxylation dominates at pH>1 while the formation of α-keto acids favors at lower pH. The formation of α-keto acids is selectively suppressed by the addition of free radical scavengers. Free radical oxidations of the acids with bromine atom or benzoyl radicals give exclusively α-keto acids. The reaction mechanism has been discussed.
Molecular Structures of Complexes of Trimethylamine with Boron Trichloride and Boron Tribromide as Determined by Gas Electron Diffraction
Authors: Iijima Kinya , Shibata Shuzo
Published: July 2006

The molecular structures of trimethylamine-boron trichloride (CH3)3N·BCl3 and trimethylamine-boron tribromide (CH3)3N·BBr3 were determined from gas electron diffraction and vibrational-spectroscopic data. The molecular parameters and their uncertainties for (CH3)3N·BCl3 were rg(B–Cl)=1.836±0.002 Å, rg(N–B)=1.652±0.009 Å, rg(C–N)=1.497±0.003 Å, rg(C–H)=1.107±0.005 Å, ∠ClBCl=110.9±0.2°, ∠CNC=108.1±0.3°, while those for (CH3)3N·BBr3 were rg(B–Br)=2.001±0.003 Å, rg(N–B)=1.663±0.013 Å, rg(C–N)=1.500±0.005 Å, rg(C–H)=1.095±0.007 Å, ∠BrBBr=110.3±0.3°, ∠CNC=107.8±0.5°. The potential barriers around the N–B bonds in (CH3)3N·BCl3 and (CH3)3N·BBr3 were also estimated to be higher than 18 kcal mol−1 and about 12 kcal mol−1 respectively.
Synthesis of a Partial Sequence of Proinsulin Using the A-Chain of Natural Insulin. II. Synthesis of a Peptide Corresponding to Positions 53–81 of Bovine Proinsulin
Authors: Aiba Hiroko , Shimonishi Yasutsugu
Published: July 2006

For the synthesis of bovine proinsulin, the S-sulfonate of the A-chain of bovine insulin was elongated by two single-step reactions using Boc–Arg(Tos)–ONSu and Boc–Leu–Glu(OBut)–Gly–Pro–Pro–Gln–Lys[Z(2-Cl)]–N3. The S-sulfonate of the Leu–Glu–Gly–Pro–Pro–Gln–Lys[Z(2-Cl)]–Arg–A-chain, corresponding to positions 53–81 of bovine proinsulin, was obtained after removal of the protecting groups. The S-sulfonates of the elongated derivatives of the A-chain were shown to be very soluble not only in water, but also in organic solvents such as DMF and DMSO in the presence of water. Therefore, these S-sulfonates could react with protected peptides in homogeneous solution. Furthermore, the S-sulfonates could easily be purified by ion-exchange chromatography. The S-sulfonates of the A-chain and its elongated derivatives are thus useful intermediates for the synthesis of proinsulin.
Quantitative Study of Metachromasy. The Analysis of the Dye–Polyphosphate Multiequilibrium System by the Principal Component Analysis Method
Authors: Takatsuki Mineo
Published: July 2006

The absorption spectra of three dyes, 9-aminoacridine (AA), Crystal Violet (CV), and Trypaflavine (TF), were measured in the presence of sodium polyphosphate (NaPP). The optical titrations were performed at phosphate residue-to-dye ratios between 26.6 and 2130 for AA, between 42.6 and 788 for CV, and between 53.9 and 1120 for TF. Using a model in which the condensation of dyes to a poly electrolyte and the bound monomer\ightleftharpoons bound aggregate equilibrium in the vicinity of the polymer are assumed, the extended principal component analysis was applied to the observed spectra of each dye–NaPP system. The equilibrium constants and the pure spectra of bound dye species were determined. Both the bound monomer and the bound dimer were present in the AA–NaPP system, while the bound monomer, bound dimer, and bound tetramer were present in both CV– and TF–NaPP systems. In all the cases, the absorption spectrum of the bound monomer showed a slight bathochromic shift. The absorption spectrum of the bound dimer of AA showed a considerable bathochromic shift without any new band, while the spectrum of the bound dimer and bound tetramer of CV and TF showed metachromasy bands in wavelength ranges both shorter and longer than the peak wavelength of free CV and TF.
Theory of A.c. Polarization and A.c. Polarography and Voltammetry of Two-step Surface Redox Reactions
Authors: Kakutani Tadaaki , Senda Mitsugi
Published: July 2006

Theoretical expressions are presented of the a.c. polarization and of the a.c. polarography and voltammetry for a two-step surface redox reaction (Oad+n1e\ightleftharpoonsSad,Sad+n2e\ightleftharpoonsRad) in which the charge transfer reactions take place exclusively between the adsorbed reactants Oad, Sad, and Rad, and all the reactants are adsorbed so strongly that the amount of O, S, or R brought to or removed from the electrode surface can be neglected. The interaction between the adsorbed reactants is assumed to be expressed by Frumkin’s a-parameters. The effect of the double layer impedance is taken into account. Several simplified cases are discussed in detail.
The Crystal and Molecular Structure of Grayanotoxin II
Authors: Furusaki Akio , Hamanaka Nobuyuki , Matsumoto Takeshi
Published: July 2006

The detailed molecular geometry of grayanotoxin II has been examined by means of X-ray crystallographic analysis. The crystals are orthorhombic, with four molecules in a unit cell with dimensions of a=10.040, b=26.517, and c=6.672 Å; the space group is P212121. 1908 unique intensity data were collected on a four-circle diffractometer with LiF-monochromated Cu Kα radiation. The structure was solved by the Monte Carlo direct method, using the 20 strongest reflections as the starting set; the 3rd random phase set led to the correct solution. The R value reached 3.8% by repeated block-diagonal least-squares refinements. The A, B, C, and D rings take envelope, twist-chair, chair, and half-chair conformations respectively. The conformation of the B ring closely resembles the preferred one of cycloheptane itself. The crystal consists of hydrogen-bonded double molecular layers piled parallel to the (010) plane.
A Quantum Chemical Study on the Ion Influence on Linear Water Polymer
Authors: Rode Bernd M , Fujikura Ryo , Fujiwara Shizuo
Published: July 2006

Quantum chemical model calculations have been performed using an STO-3G basis set for linear water polymers under the influence of electrostatically approximated cations and anions. It is found that the influence of the cations on the ligand chains can be described properly as a purely electrostatic interaction from the third water molecule on. The mutual influencing of cation and anion in ion pairs separated by more than one solvent molecule seems to be also a merely electrostatic one. An estimation of the range of these electrostatic forces is given.
The Reaction of cyclo-Triphosphate with l-Valine
Authors: Tsuhako Mitsutomo , Fujita Naoko , Nakahama Akiko , Matsuo Tsuneo , Kobayashi Masamitsu , Ohashi Shigeru
Published: July 2006

The reaction of cyclo-triphosphate(P3m) with l-valine in an aqueous solution was studied by means of anionexchange chromatography, paper chromatography, chemical analysis for phosphorus and valine, IR spectroscopy, and ninhydrin reaction. 1) P3m reacted with l-valine at pH 10–12 to form an unknown compound, the amount of which reached about 22% at pH 12 and about 9% at pH 10. This compound decomposed into orthophosphate(P1) and valine at a lower pH. 2) The unknown compound was proved to be a P1-derivative of valine, (Remark: Graphics omitted.), which has a P–N bond in its molecule. 3) In the reaction of P3m with l-valine at pH 10, in addition to the unknown compound, small amounts of tetra(P4) and pentaphosphate(P5) were produced. 4) The disappearance rate of P3m in this reaction was first-order, and its rate constants were 0.317 and 0.138 d−1 at pH 12 and 10 respectively at room temperature. 5) Short-chain phosphates, such as P1 pyro (P2), and triphosphate(P3), did not react with l-valine at all. 6) The mechanism of the reaction of P3m with l-valine was discussed.
The Reductive Acylation of Organic Disulfides with Aldehydes under Photochemical and Radical Conditions
Authors: Takagi Makoto , Goto Setsuo , Tazaki Masato , Matsuda Tsutomu
Published: July 2006

The irradiation of organic disulfides in aldehyde solvents resulted in the reductive fission of the S–S linkage, giving an equimolar mixture of the corresponding thiol and the thiol acylate in a good yield. The cyclic disulfides gave mono S-acylated dithiols. The reaction proceeded by means of the photo-initiated radical chain mechanism, and AIBN (azobisisobutyronitrile) effected the same reaction under thermal conditions.
Electronic Structures and Conformations of N-Benzylideneanilines. I. Electronic Absorption Spectral Study Combined with CNDO/S CI Calculations
Authors: Akaba Ryoichi , Tokumaru Katsumi , Kobayashi Tsunetoshi
Published: July 2006

The electronic structures and molecular conformations of N-benzylideneaniline and its several derivatives bearing 2-methyl, 2,6-dimethyl, and/or 4-nitro groups on the anilino benzene ring (ring A) have been investigated by electronic absorption spectroscopy combined with CNDO/S CI calculations. The lower energy bands are assigned and the molecular conformations are estimated. The results show that the 4-nitro derivatives as well as the 2,6-dimethyl derivatives take considerably twisted conformations.
Electrochemical Generation of Unstable Nitrogen Species. Part 4. Electrochemical and Chemical Oxidation of Cyclic and Open-chain Diamines. The Formation of Cyclic Hydrazine Derivatives
Authors: Fuchigami Toshio , Iwaoka Tomoyasu , Nonaka Tsutomu , Sekine Taro
Published: July 2006

Intramolecular N,N-coupling by the electrochemical oxidation of cyclic and open-chain diamines such as 3,3,7,7-tetraethylperhydro-1,5-diazocine (1) and N,N-dimethyl-2,2-diethyl-1,3-diaminopropane (2) was investigated with the use of platinum, silver, nickel, and carbon anodes. In the case of 1, cyclic hydrazine derivatives, 3,3,7,7-tetraethyl-1,5-diazabicyclo[3.3.0]octane and 1-(2-ethyl-2-formylbutyl)-4,4-diethyl-4,5-dihydropyrazole, were formed in high current efficiency. In the case of 2, the corresponding hydrazines, 1,2-dimethyl-4,4-diethylpyrazolidine and 1-methyl-3,3-diethyl-4,5-dihydropyrazole, were obtained in low current efficiency, because C–N bond cleavage took place before N,N-coupling. A carbon anode was found to be effective for N,N-coupling of such diamines. Chemical oxidative N,N-coupling of 1 and 2 was studied by using sodium peroxodisulfate and lead tetraacetate.
Catalysis by 12-Heteropolymolybdic Acid. II. Friedel-Crafts-type Reaction of Aromatic Compounds
Authors: Nomiya Kenji , Sugaya Yoshio , Sasa Sadayoshi , Miwa Makoto
Published: July 2006

12-Heteropolymolybdic acid, a heteropolyacid of Keggin-structure, behaves as an effective catalyst of the Friedel-Crafts-type reactions for aromatic compounds, such as alkylation by benzyl chloride and t-butyl chloride, acylation by acetyl chloride, and sulfonylation by tosyl chloride. The catalyst mainly gives para-substituted products for phenol and anisole. The reactions proceed via carbocation-generation mechanism brought about by the strong Brønsted acid.
Telomerization of Isoprene with Dialkylamine Catalyzed by Palladium Complexes
Authors: Hidai Masanobu , Mizuta Haruyoshi , Hirai Kiyomiki , Uchida Yasuzo
Published: July 2006

Telomerization of isoprene with diethylamine in the presence of catalytic amounts of palladium chloride and triphenylphosphine under carbon dioxide and/or using methanol as solvent gave three kinds of 2:1 adducts in good yields, one of which was found to be an adduct of new type.
Restricted Rotation Involving the Tetrahedral Carbon. XXXI. Barriers to Rotation in 2,3-Dichloro-9-(1-cyano or 1-methoxycarbonyl-1-methylethy)triptycenes
Authors: Otsuka Soichi , Yamamoto Gaku , Mitsuhashi Tsutomu , Oki Michinori
Published: July 2006

The title compounds were prepared to see the effects of substituents in 1-position on the barriers to rotation about the C9–Csubst bond. The barrier was found to be higher for the cyano compound than those for the corresponding compounds carrying a substituent in 1-position, whereas the methoxycarbonyl compound gave almost the same barrier irrespective of the substituent.
Heterogeneous Catalysis in the Liquid-phase Oxidation of Olefins. IV. The Activity of a Supported Vanadium or Chromium Oxide Catalyst in the Decomposition of t-Butyl Hydroperoxide
Authors: Takehira Katsuomi , Hayakawa Takashi , Ishikawa Toshio
Published: July 2006

The liquid-phase decomposition of t-butyl hydroperoxide (t-BuOOH) has been carried out in benzene under an N2 atmosphere using a vanadium or chromium oxide, supported on γ-Al2O3 or SiO2 as the catalyst, for the purposeof clarifying the reaction mechanism of the cyclohexene oxidation. The decomposition of t-BuOOH on the supported oxide catalyst was a first-order reaction; the main products were t-butyl alcohol, di-t-butyl peroxide, and acetone, suggesting that t-BuOOH is decomposed homolytically on the catalyst by the Haber-Weiss mechanism. The effect of the vanadium–chromium binary system formation was small, but the interaction between metal oxides and the supports appeared to be important in the t-BuOOH decomposition. Tetrahedrally co-ordinated vanadium species were formed on SiO2 and showed the highest activity, followed by the chromium co-ordinated tetrahedrally on SiO2 or on γ-Al2O3, while an octahedrally co-ordinated vanadium or chromium showed low activity. Such order of the activity was in good agreement with that obtained in the liquid-phase oxidation of cyclohexene. We observed a relatively good correlation between the catalytic activity and the acidity of the supported binary metal oxides. The V2O5–SiO2 system showed an especially large acidity; here t-butyl alcohol was dehydrated into di-t-butyl ether and 2-methyl propene.
The Crystal Structure of the A′-form of Tridecanoic Acid
Authors: Goto Midori , Asada Eiichi
Published: July 2006

The A′-form of tridecanoic acid is triclinic, with the space group P\bar1 and with a=4.273(1), b=4.972(1), c=37.69(1) Å, α=90.36(2), β=109.44(2), and γ=112.43(2)°. The structure was determined by the Patterson method. Refinement by block-diagonal least-squares methods gave a final R factor of 0.071.
The Thermal Desorption of Surface Hydroxyls on Tin(IV) Oxide
Authors: Morishige Kunimistu , Kittaka Shigeharu , Morimoto Tetsuo
Published: July 2006

The structure of the adsorbed layer of water on SnO2 was investigated by means of thermal desorption, water physisorption, and electron diffraction, using four kinds of SnO2 samples which differ in method of preparation. Two distinct peaks appear around 513 and 573 K in the thermal-desorption spectra. The peak around 513 K is due to the condensation dehydration of hydroxyls on the (100) plane of SnO2, on which the two-dimensional condensation of water occurs. The peak around 573 K is associated with that on the (101) plane, on which the physisorption of water is strong and the two-dimensional condensation of water does not occur. The portion of the (100) plane occupied by water molecules is relatively small, and the 1 : 4 ratio (H2O : OH) holds also on the surfaces on which the two-dimensional condensation of water does not occur. In conclusion, the fully hydroxylated surfaces of SnO2 are hydrophobic in the sense that they sparsely adsorb water molecules.
Film Dichroism. V. Linear Dichroism Study of Acridine Dyes in Films with Emphasis on the Electronic Transitions Involved in the Long-wavelength Band of the Absorption Spectrum
Authors: Matsuoka Yukio , Yamaoka Kiwamu
Published: July 2006

The long-wavelength bands of the absorption spectra of 10-methylacridinium (MeAcr), Acridine Orange (AO), and Acridine Yellow (AY) in the poly(vinyl alcohol) film were investigated by the linear dichroism method. The parallel- and perpendicular-dichroic spectra of each dye were resolved into the long-axis and short-axis polarized absorption components. From these component bands the isotropic spectrum was reconstituted and the reduced dichroism spectrum was simulated by computer with a new technique which utilizes a general expression for the reduced dichroism of planar molecules with the multiple band structure. A weak absorption band (or bands) hidden in a strong one could be revealed by reproducing the observed isotropic and linear-dichroic spectra. The vibrational sub-bands of MeAcr were shown to have the average intervals of ca. 1.5×103 cm−1 for the short-axis polarized 1La band and of ca. 0.7×103 cm−1 for the long-axis polarized 1Lb band. In the visible region of the isotropic spectrum, the weak 1La band of AO was clearly shown to consist of the fine structure with a regular energy separation, although it is overlapped with the intense 1Lb band which is also composed of a vibrational structure. The same spectral feature was observed for AY. The dichroic results are discussed under considerations of (1) the overlap of the mutually orthogonal transition moments, whose angles were determined relative to the long axis of the C2v-symmetric dye molecule, (2) the angle between the orientation axis and the long axis of the molecular plane, and (3) the average degree of orientation of dye molecules in the film.
Thickness Measurement of Surface Layer by the Angular Dependent X-Ray Photoelectron Spectroscopy
Authors: Yamada Masamichi , Kuroda Haruo
Published: July 2006

A sample-holding device to study the photoelectron take-off angle dependence of XPS spectrum is described. The take-off angle dependence was studied on a silicon surface covered with an oxide layer and a contamination carbon layer, and the (thickness)/(electron attenuation length) ratio of each layer was determined from the analysis of the angular dependence of the Si2p, O1s, and C1s peak intensities.
Fluorescence Quenching Process of Anthracene by Maleic Anhydride
Authors: Yesaka Hiroshi , Kobayashi Takayoshi , Suzuki Kaoru , Nagakura Saburo
Published: July 2006

The time dependence of fluorescence intensity after picosecond laser excitation and the steady-state fluorescence intensity were measured in order to study the mechanism of fluorescence quenching of anthracene by maleic anhydride in 1,4-dioxane. The nonlinear relationship between the reciprocal of steady-state fluorescence intensity and quencher concentration was observed for this system and interpreted in terms of the transient effect in the quenching process. The kinetic study by picosecond laser photolysis supports this interpretation. The reaction radius (R) and the sum of diffusion constants of both reactants (D) at various temperatures were determined by applying the diffusion model of Andre et al. The observed values are R=7.2 Å, D=1.46×10−5 cm2 s−1 (22 °C), 1.87×10−5 cm2 s−1 (50 °C), 2.42×10−5 cm2 s−1 (75°C). Studies of the main path in the quenching process by nanosecond laser photolysis suggest the existence of an extra path in the quenching process which overwhelms the fluorescent exciplex formation, the photoionization, the triplet anthracene formation, and the adduct formation.
Photodissociation Spectroscopy and Photoreactions in t-Butylbenzene Cation and Its Daughter Cations
Authors: Takenoshita Yoshiya , Dunbar Robert C
Published: July 2006

Photodissociation spectra were observed for t-butylbenzene cation (m/e 134) and its daughter ion (m/e 119). Photoproduction spectra of the ions at m/e 119 and m/e 91 were observed in the visible region. It was shown that the photodissociation of m/e 134 yields m/e 119 almost 100% at wavelengths above 450 nm. Below 450 nm m/e 91 and m/e 57 appear as light-produced species. From pressure dependence and double resonance results, it was concluded that m/e 91 is a direct photoproduct from m/e 119, and that m/e 57 is produced in an ion-molecule reaction of m/e 91 with neutral t-butylbenzene. The photodissociation spectrum of m/e 119 is very similar to that of m/e 105 obtained by protonation of styrene, and it is reasonable to assume that m/e 119 has the protonated methylstyrene structure.
Photo-induced Alkoxybromination of Olefins by N,N′-Dibromo-2,5-piperazinedione
Authors: Sera Akira , Yamada Hiroshi , Itoh Kuniaki
Published: July 2006

Irradiation of N,N′-dibronio-2,5-piperazinedione in dichloromethane in the presence of an alcohol induced alkoxybromination of cyclohexene to give trans-1-bromo-2-alkoxycyclohexane in a good yield. The reaction was thought to proceed through an ionic mechanism.
Electrochemical and Spectroscopic Studies of α,β,γ,δ-Tetrakis[1-(2-hydroxyethyl)pyridinium-4-yl]porphine and Its Metal Complexes
Authors: Kobayashi Nagao , Fujihira Masamichi , Osa Tetsuo , Kuwana Theodore
Published: July 2006

The preparation and properties of a water soluble porphyrin having functional groups, α,β,γ,δ-tetrakis[1-(2-hydroxyethyl)pyridinium-4-yl]porphine, are described. This porphyrin is water soluble from below pH 0 to above pH 14. Acid-base titration revealed the diprotonated diacid-monocation equilibrium (pK4=1.0) and the monocation-free base equilibrium (pK3=1.9) in the acidic range and the free base-monoanion equilibrium (pK2=13.0±0.2) in the basic region. The zinc, iron, and cobalt derivatives of the porphyrin were also synthesized and purified. Catalytic properties of the iron and cobalt complexes for reduction of molecular oxygen in water are reported in terms of cyclic voltammetry. The electrochemical reduction utilizing these complexes was interpreted to proceed via electrochemical catalytic regeneration mechanism as had been observed for tetrakis(1-methylpyridinium-4-yl)orphinatoiron(III). The apparent rate constants for electron transfer from the iron and cobalt porphyrins to oxygen were estimated to be 3–4×107 and 1×107 dm3 mol−1 s−1, respectively.
The Crystal and Molecular Structure of γ-Metasantonin
Authors: Ueda Hideo , Katayama Chuji , Tanaka Jiro
Published: July 2006

The crystal and molecular structure of γ-metasantonin has been determined by the X-ray method. The crystal is orthorhombic, P212121, with lattice parameters a=10.371(1), b=7.904(1), c=15.975(1) Å. The molecule has two independent α,β-unsaturated ketone chromophores which take a chiral configuration. The chromophores show good planarity. A/B ring fusion is cis.
Synthesis and Photoreaction of D-Nor-5α-androstan-16-one Acetylhydrazone in the Presence of Oxygen
Authors: Suginome Hiroshi , Uchida Tsutomu , Kizuka Kazuhiko , Masamune Tadashi
Published: July 2006

D-Nor-5α-androstan-16-one was prepared via seven steps from 16-diazo-3β-hydroxyandrost-5-en-17-one. The major products of the photolysis of its acetylhydrazone in dioxane containing oxygen were the parent ketone and 17-oxa-5α-androstan-16-one, accompanied by low yields of three isomeric lactams: 17-aza-5α-androstan-16-one, 16-aza-5α-androstan-17-one, and 17-aza-5α,13α-androstan-16-one. These three are the same lactams formed in the photo-Beckmann rearrangement of the corresponding oxime, D-nor-5α-androstan-16-one oxime. Their formation from the acetylhydrazone may have some mechanistic significance with regard to the path of the formation of lactams in the photolysis of 5α-androstan-17-one acetylhydrazone in the presence of oxygen reported previously. The mass spectrometric fragmentations of fifteen D-nor-5α-androstanes with functional groups at their C-16 positions are described.