bluuebunny/crossref_metadata_2025 huggingface dataset:
Ortho Effects in Organic Molecules on Electron Impact. VIII. Intramolecular Aromatic Substitution in (Arylmethylene)barbituric Acids
Authors: Ramana Devalla Venkata , Kasi Viswanadham Somayajula
Published: July 2006

Mass spectral decomposition process involving intramolecular aromatic substitution with the ejection of either the hydrogen or the substituent in the ortho position from the M+· ion is noticed in the eleven 5-(arylmethylene) barbituric acids studied. It has been generally noticed that for such a cyclization to occur, the presence of an α,β-unsaturated carbonyl function, in conjugation with the ring, is essential in aromatic systems.
Bulk Copolymerization of Acrylonitrile with α-Chloroacrylonitrile
Authors: Okamoto Masao , Ishizuka Osamu
Published: July 2006

Copolymerization of acrylonitrile (M1) with α-chloroacrylonitrile (M2) was carried out at 60 °C using 4.3×10−2 mol% of α,α′-azobisisobutyronitrile. The four copolymers obtained were analyzed, their mole fractions of α-chloroacrylonitrile units being 0.196, 0.377, 0.532, and 0.722, and the monomer reactivity ratios r1 and r2 were found to be 0.31 and 3.25, respectively.
The Solvent Effects of Water–Dimethyl Sulfoxide Mixtures on the Keto-Enol Tautomerization Rate of Di-n-alkyl β-Diketones
Authors: Watarai Hitoshi
Published: July 2006

The kinetic solvent effects of water–dimethyl sulfoxide (DMSO) mixtures on the ketonization and the enolization rate constants of eight di-n-alkyl β-diketones were analyzed in terms of the group-transfer free energy from water to the mixed solvents. The transfer free energy of the transition state, as calculated from the rate constant and the partition coefficient of the keto or enol form, is found to be divided into three contributions: the two group-transfer free energies of the “transition state skeleton” and the methylene group, and the transfer free energy change due to the inductive effect of the n-alkyl group.
Kinetic Studies of the Electron Transfer Reaction in Iron(II) and Iron(III) Systems. X. The Electron Transfer Reaction between Iron(II) and Iron(III) in the Presence of Pyridine in Aqueous Solution
Authors: Wada Goro , Kawauchi Aiko
Published: July 2006

When pyridine is added to the reaction system of the electron transfer between Fe(II) and Fe(III) in aqueous solution at constant [HClO4]o, the apparent rate constant k grows rapidly with [Py]o at [Py]o[HClO4]o. The predominant paths of the reaction will be discussed.
A.c, Polarographic Determination of Cyanide Ion after Conversion to Mercury(II) Cyanide by Use of Hg-form Resin
Authors: Hanagata Goro , Ohzeki Kunio , Kambara Tomihito
Published: July 2006

Cyanide ion was converted to mercury(II) cyanide by shaking with Hg(II)-form resin and determined by a.c. polarography at pH 9.0. The recovery was 80.5%. A linear calibration curve was obtained in the cyanide concentrations ranging from 10−4 to 10−3 M (1 M=1 mol dm−3).
Evidence for Electron-transfer Process in Abnormal Grignard Reactions. Enolization and α-Diketone Formation
Authors: Okubo Masao , Morigami Yoshiaki , Suenaga Reiko
Published: July 2006

The effect of 2,6-dimethyl groups on enolization vs. addition in the reaction of PhMgBr with PhCH2COPh, and also the formation of α-diketone from 2,4,6-Me3C6H2COCl by the treatment with MeMgX and i-PrMgX in the presence of CoCl2, were studied. The results were discussed on the basis of electron-transfer mechanism.
A New Synthesis of Allethrolone
Authors: Ono Noboru , Tanabe Yo , Tanikaga Rikuhei , Kaji Aritsune , Matsuo Takashi
Published: July 2006

A new synthesis of 2-allyl-4-hydroxy-3-methyl-2-cyclopenten-1-one, so called allethrolone is described, in which the Michael addition of 3-phenylthio-5-hexen-2-one to 1-nitro-1-propene followed by conversion of the nitromethyl group in the adduct to an aldehyde function is involved as the key step.
ESR Studies of Abnormal Methyl Radicals on Various Solid Surfaces
Authors: Oduwole Duro A , Wiseall Barrie
Published: July 2006

Direct spectroscopic evidence is presented that strongly caged methyl iodide (or methane) molecules in porous surfaces are the precursors of abnormal methyl radicals. The implication of this result as concerns the nature of radical surface interaction is discussed in terms of a matrix effect.
The Hydrothermal Activation of Silica–Alumina for Butene Isomerization. A Device to Prepare a Standard Sample
Authors: Furuyama Shozo , Murashita Osamu , Yukumoto Yuko , Morimoto Tetsuo
Published: July 2006

Three kinds of silica–alumina catalysts were prepared by hydrothermal treatment (heating a sample in hot water) over the range of 25–250 °C for various periods. It was found that the hydrothermal treatment significantly increased its catalytic activity for butene isomerization. The dependencies of various surface properties (the production ratio of 2-butene isomers, the surface acidity, the surface area, the pore-size distribution, and the shape and size of the catalyst particle) on the hydrothermal conditions and the kind of starting catalyst sample were systematically investigated, too. It was concluded that the increase in the catalytic activity might be due to the progress of the Si/Al isomorphic substitution in the tetrahedral surface silica network. Hot water might serve as a solvent for the cations and facilitate their movements. Since the hydrothermal treatment can erase the effects of the blending method on the catalytic activity and other surface properties almost completely, this treatment can be used to prepare a standard sample.
Studies of the Magnetic Circular Dichroism and Tautomerism of Pyridinols (Pyridinones) and Pyrimidinols (Pyrimidinones)
Authors: Kaito Akira , Hatano Masahiro
Published: July 2006

The magnetic circular dichroism(MCD) spectra of pyridinols (pyridinones) and pyrimidinols (pyrimidinones) were measured in the wavenumber region of 27000–50000 cm−1. The transition energies, the oscillator strengths, and the Faraday B terms were calculated within the framework of the INDO/S-CI approximation. The calculated results for the π*←π transitions were in good agreement with the experimental results. The lactim-lactam tautomerism of 3-pyridinol(3(1H)-pyridinone) and 2-pyrimidinol (2-pyrimidinone) was discussed.
Liquid Crystal Formation in Binary Systems. II. Induction of Nematic and Smectic Phases by Electron Donor-Acceptor Interaction between the p-Dimethylamino and p-Nitro Derivatives of N-Benzylideneaniline
Authors: Araya Kotaro , Matsunaga Yoshio
Published: July 2006

The formation of solid molecular complexes and the induction of nematic and smectic phases have been demonstrated with a number of binary mixtures of potentially-mesomorphic electron donors and acceptors of the type N-(p-X-benzylidene)-p-Y-aniline. One of the components contains a dimethylamino group as X or Y, and the other a nitro group as X or Y. The remaining substituents are methoxyl, ethoxyl, or propoxyl groups. The maximum temperature of the nematic phase induced in these electron donor-acceptor systems is higher by 23 to 45 °C than the straight line joining the latent transition temperatures of the two components. The tendency to form a solid complex and that to induce a nematic phase are both shown to a large extent by the propoxy derivatives, to a lesser extent by the methoxy derivatives, and least by the ethoxy derivatives. All the solid molecular complexes are reddish brown and exhibit an additional electronic absorption band located at about 500 nm. The mesophases are similarly colored. The enhanced thermal stability of the nematic and smectic phases in these binary mixtures is ascribed to the complex formation by an electron donor-acceptor interaction.
Charge Transfer and Proton Transfer in the Formation of Molecular Complexes. XII. o-Aminobenzoic Acid–Picric Acid and Related Complexes
Authors: Matsunaga Yoshio , Usui Reiko
Published: July 2006

The combination of o-aminobenzoic acid and picric acid was found to yield four kinds of adducts. These were a stable yellow (1:1) salt, formed by the proton transfer from the picric acid to the o-aminobenzoic acid molecule, two red (1:1) molecular complexes of markedly different stability, and a red (2:1) complex consisting of the o-aminobenzoic acid molecule, its protonated ion, and the picrate ion. The enthalpy change and the activation energy for the isomerization from the salt to the charge-transfer complex by a solid-solid transformation were shown to decrease during storage. The 1,3,5-trinitrobenzene complexes with o-(methylamino)benzoic acid, o-, m-, and p-(dimethylamino)benzoic acids, and their sodium and potassium salts were prepared. Their electronic spectra were measured, along with those of the complexes with o- and p-aminobenzoic acids and their salts presented in the work of Sudborough and Beard. The displacement of the charge-transfer absorption maxima to the lower wavenumber side by the salt formation is 2×103 cm−1 on the average and seems to be consistent with our proposition that the picrate ion acts as an electron acceptor in aromatic amine-picric acid (2:1) complexes.
The Isomerization of cis-2-Butene over SO2-adsorbing Mg(OH)2 and MgO
Authors: Otsuka Kiyoshi , Tanaka Kimiaki , Morikawa Akira
Published: July 2006

The reaction of butenes caused by the surface compounds formed from SO2 on Mg(OH)2 or MgO has been studied. It has been shown that the cis-trans isomerization of 2-butene is selectively induced by the sulfur compounds. This specific isomerization has been explained by the previously proposed mechanism that the reaction is accompanied by the copolymerization of 2-butene and SO2. The infrared spectroscopic study on the sulfur compounds formed on Mg(OH)2 or on MgO has demonstrated the presence of SO32−, SO42−, or sulfinato complexes. The formation of these surface species may cause a strong electrostatic field on the surface, resulting in the polarization of reactant molecules, which is necessary for the initiation of the copolymerization or of the cis-trans isomerization. It has been shown, however, that the presence of weakly adsorbed SO2 is essential for determining the catalytic activities of the solids in the SO2-induced isomerization.
Electronic Spectra of Single Crystals of 1,1′-Diethyl-2,2′-Cyanine Iodide, Bromide, and Chloride
Authors: Tanaka Jiro , Tanaka Masashi , Hayakawa Masuo
Published: July 2006

Reflection spectra of single crystals of 1,1′-diethyl-2,2′-cyanine iodide, bromide and chloride were measured in order to find the origin of the J band. The spectra were obtained by the Kramers-Kronig transformation of reflectivity. The positions of absorption peaks and the shapes of vibronic envelope for each crystalline faces are explained by a calculation of surface exciton splitting with a weak coupling model. The intensity of each bands is interpreted by the oriented gas model, however, a peculiar anomalous band shape characteristic of J band is explained by the charge resonance (CR) and the molecular exciton interaction. The J band is found along particular crystalline direction, in which the dye molecules are stacked face to face, showing importance of interplanar π electron interaction. The molecular exciton band shape is changed significantly to give a J band because the higher vibronic bands are blurred off by the enhanced relaxation mechanism of the CR interaction.
Behavior of Sulfate Ions daring Formation of Anodic Oxide Film on Aluminium
Authors: Fukuda Yoshio , Fukushima Toshiro
Published: July 2006

The incorporation of sulfate into anodic film formed on aluminium in an H2SO4–MgSO4 solution was investigated by infrared spectroanalysis using the compensation method. The sulfate content of the film was very small at the initial stage of anodizing, but increased with time to a nearly constant value. This result is explained in terms of the variation of strength of electric field and the mobility of each anion in the barrier layer. The distribution of sulfate across the cell wall also was examined. The sulfate content was relatively small near the wall/solution interface, but increased with the distance across the wall from the surface, reached a maximum value on the intermediate layer between the wall/solution interface and the cell boundary, and decreased gradually. Such distribution is considered to be similar to that across the barrier layer. The SO4 distribution and the transfer of anions from the barrier layer to the porous layer are explained.
On the Excimer Formation of Pyrene in Electrochemiluminescenece
Authors: Suminaga Takeshi , Hayakawa Sohachiro
Published: July 2006

Temperature effect in electrochemiluminescenece (ECL) of pyrene was investigated in order to clarify the formation of excimers. The ratio of intensity of excimer to monomer emission was measured on solutions of pyrene in N,N-dimethylformamide (DMF) at various temperatures from the decay curves of excimer emission due to pulse excitation with a nitrogen laser. The temperature change of concentration dependence of the ratio was derived from the rate equations for the respective direct and indirect formation of excimers. The mechanism of direct excimer formation was confirmed in ECL of pyrene more clearly by analysis of the temperature effect than by that of the concentration effect at a certain temperature.
The Temperature Dependence of the Mixed and Intervalence State in Mono-oxidized trans-μ-(as-Indacene)bis(cyclopentadienyliron)
Authors: Iijima Sei’ichiro , Motoyama Izumi , Sano Hirotoshi
Published: July 2006

The temperature dependence first observed in the Mössbauer spectrum for mono-oxidized trans-μ-(as-indacene)bis(cyclopentadienyliron) was interpreted in terms of the increase in the rate of intervalence-electron transfer between two irons with an increase in the temperature. The cyclic voltammetric study of trans-μ-(as-indacene)bis(cyclopentadienyliron) indicates that the metal-metal interaction in the monocation of the compound is greater than that in the monocation of biferrocene at room temperature.
Hypochlorite Oxidation of Ammonia. Effective Removal of Ammonia from Waste Water by UV-irradiation
Authors: Kimura Makoto , Suzuki Teiichi , Ogata Yoshiro
Published: July 2006

The hypochlorite oxidation of ammonia giving rise to nitrogen evolution was carried out in the dark or under irradiation in order to study the reaction mechanism and application to waste water treatment. UV-irradiation accelerates remarkably the rate of decomposition of unfavorable chloramines. The acceleration covers the pH region 2–12, where corresponding dark reactions are slow. The irradiation also affects the formation of byproducts such as NO2− and NO3−, the effect being a slight increase in NO2− formation in the pH range 2–12. These results suggest an effective industrial application to avoid eutrophication in seas and lakes. The irradiation effect is discussed in relation to reaction mechanism, in which the irradiation possibly facilitates the N–N bond formation after chloramine formation.
Metal Complexes of Peptides. I. The Cobalt(III) Complexes Containing Dipeptidate and N-Methyliminodiacetate as Mixed Ligands
Authors: Kawaguchi Hiroshi , Kanekiyo Makoto , Ama Tomoharu , Yasui Takaji
Published: July 2006

The mixed-ligand complexes, Ba[Co(mida)(dipept)]2 (where mida is N-methyliminodiacetate and dipept denotes dianions of glycyl-l-alanine, l-alanylglycine, glycyl-l-leucine, l-leucylglycine, glycyl-β-alanine, β-alanyl-glycine, l-alanyl-β-alanine, and β-alanyl-l-alanine) have been prepared. The structure and properties of these complexes have been characterized by their electronic absorption, CD, and NMR spectral data.
Monochromatic Light-induced Reactions of Benzophenone Hydrazones and the N-Acetyl Derivatives in Carbon Tetrachloride in the Presence of Oxygen
Authors: Suginome Hiroshi , Uchida Tsutomu
Published: July 2006

Irradiation of hydrazones of benzophenone, 4-methylbenzophenone and 4-methoxybenzophenone in carbon tetrachloride with monochromatic light in the presence of oxygen afforded the corresponding azine, resulting from N–N bond cleavage, as the major product together with the hydrazone hydrochloride. In contrast to the hydrazones, benzophenone acetylhydrazone in carbon tetrachloride in the presence of oxygen afforded an unstable hydroperoxide as the only product, on photolysis with monochromatic light (288±8 nm); this product was transformed spontaneously into benzophenone on evaporation of the solvent at room temperature. 4-Methylbenzophenone acetylhyd razone and 4-methoxybenzophenone acetylhydrazone reacted in a manner similar to benzophenone acetylhydrazone. Irradiation of benzophenone diacetylhydrazone with 266±8 nm light under conditions analogous to the photo-reactions of hydrazones and acetylhydrazones resulted in loss of an acetyl group, resulting in N–CO bond cleavage to afford acetylhydrazone. The mechanism of the photooxygenation of benzophenone acetylhydrazones is interpreted in terms of chlorine radical-induced autoxidation.
Reduction by a Model of NAD(P)H. 28. Reduction of an α-Diketone in the Presence of Zinc Ion
Authors: Ohno Atsuyoshi , Yasui Shinro , Oka Shinzaburo
Published: July 2006

Reduction of 1-phenyl-2-(2-pyridyl)-1,2-ethanedione with 1-benzyl-1,4-dihydronicotinamide in acetonitrile in the presence of zinc perchlorate has been studied. The α-diketone coordinates onto zinc ion through its pyridine-ring nitrogen and benzene-side carbonyl oxygen, whereas the reduction takes place on pyridine-side carbonyl group. It is concluded that an effective ligand to a metal ion is not necessarily a facile substrate of the reduction.
Substituent Effects in Heterogeneous Catalysis. VII. Temperature Independence of the Relative Rates in Metal-catalyzed Hydrogenation of Cyclohexanone and Its 2-Alkyl Derivatives
Authors: Chihara Teiji , Tanaka Kazunori
Published: July 2006

The rates of hydrogenation of cyclohexanone and its 2-alkyl derivatives have been measured using decalin as the solvent in a temperature range of −5 to 68 °C over Ru/Al2O3, Rh/Al2O3, and Pt/Al2O3 catalysts. As predicted previously, 2-methyl-, 2-ethyl-, and 2-propylcyclohexanone have exhibited nearly identical temperature dependencies in adsorption and hydrogenation, while cyclohexanone and 2-isopropylcyclohexanone had quite different dependencies.
Acid-catalyzed Rearrangement of the exo-1,2-Dioxetane Derivative from 1-Isopropylidene-4,4-diphenyl-2,5-cyclohexadiene
Authors: Kawamoto Akira , Uda Hisashi , Harada Nobuyuki
Published: July 2006

It is shown that acid-catalyzed decomposition of the 1,2-dioxetane derivative, 3,3-dimethyl-7,7-diphenyl-1-2-dioxaspiro[3.5]nona-5,8-diene, obtained from 1-isopropylidene-4,4-diphenyl-2,5-cyclohexadiene, gives 1-methyl-1-(o-terphenyl-4′-yl)ethyl hydroperoxide, bis[1-methyl-1-(o-terphenyl-4′-yl)ethyl] peroxide, 1-(1-hydroperoxy-1-methylethyl)-4,4-diphenylcyclohexa-2,5-dien-1-ol, and o-terphenyl-4′-ol, along with the usual dioxetane-scission product, 4,4-diphenyl-2,5-cyclohexadienone. The distribution and yield of these products depend on acidic agents and/or conditions employed.
A Kinetic Study of the Reaction of 1-Propyl-1,4-dihydronicotinamide with Hexacyanoferrate(III)
Authors: Okamoto Tadashi , Ohno Atsuyoshi , Oka Shinzaburo
Published: July 2006

The reaction of 1-propyl-1,4-dihydronicotinamide with hexacyanoferrate(III) in 20% aqueous methanol follows a second-order rate law with first order with respect to each reactant concentration. Kinetic parameters are ΔH\eweq: (8.8±0.4)×103 J mol−1 and ΔS\eweq: −1.8×102 J mol−1 K−1, the observed kinetic isotope effect, kH/kD, being 1.51. The mechanism of the reaction is discussed.
A New and Highly Effective Aldol Synthesis
Authors: Maruoka Keiji , Hashimoto Shinsuke , Kitagawa Yoshizo , Yamamoto Hisashi , Nozaki Hitosi
Published: July 2006

A new approach has been demonstrated for the regiospecific aldol synthesis by the simultaneous addition of α-halo carbonyl derivatives and aldehydes or ketones to a suspension of diethylaluminum chloride and zinc in tetrahydrofuran at low temperature. This technique is also employable under mild conditions for the Reformatsky reaction to give β-hiydroxy esters in excellent yield. One of the unique synthetic applications of this process is illustrated by the intramolecular cyclization of α-bromo esters of ω-hydroxy aldehyde, which produces macrolides, an important class of compounds in the antibiotic field.
Silver(I) Ion-catalyzed Rearrangement of 3,5-Dehydronoriceane (Pentacyclo[5.3.1.02,6.03,5.04,9]undecane). Empirical Force-field Calculations and Behavior of 3-Noricyl (Tetracyclo[5.3.1.02,6.04,9]undec-3-yl) Cation
Authors: Katsushima Takeo , Yamaguchi Ryohei , Kawanisi Mituyosi , Osawa Eiji
Published: July 2006

Treatment of 3,5-dehydronoriceane (1) with a catalytic amount of silver tetrafluoroborate results in a novel skeletal rearrangement to afford tetracyclo[5.3.1.02,6.03,9]undec-4-ene (2,4-ethenonoradamantane) (5) in 85% yield. Empirical force-filed calculations suggest that there is no substantial difference in strain energies between 1 and bicyclo[2.1.0]pentane which is inert toward silver(I) ion. Acetolysis of endo-3-noricyl (endo-tetracyclo[5.3.1.02,6.04,9]undec-3-yl) tosylate (7) gives exo-3-acetoxynoriceane (exo-3-acetoxytetracyclo[5.3.1.02,6.04,9]undecane) (11), exo-4-acetoxytetracyclo[5.3.1.02,6.03,9]undecane (12), and 5 in a ratio of 36:42:22. Similar acetolysis of the exo-isomer of 7 gives the same products but in a different ratio (11:12:5=9:47:44). A stepwise carbocation mechanism is proposed for the above mentioned silver(I) ion-catalyzed rearrangement.
α-Cyclodextrin-catalyzed Hydrolysis of 2,2,2-Trifluoroethyl 4-Nitrobenzoate
Authors: Komiyama Makoto , Inoue Shohei
Published: July 2006

The hydrolysis of 2,2,2-trifluoroethyl 4-nitrobenzoate (1) was catalyzed by α-cyclodextrin at pH 8.6, 16 °C. The reaction, involving the complex formation of 1 with α-cyclodextrin, proceeded mostly (80%) via the general base catalysis by the secondary alkoxide ion of α-cyclodextrin with 20% contribution of the nucleophilic catalysis. This is the first finding of the general base catalysis of the hydrolyses of esters by cyclodextrins. The rate constants of the cleavage of 1 by the general base catalysis and the nucleophilic catalysis, respectively, of α-cyclodextrin were 5.3×10−2 and 1.5×10−2 min−1, whereas the value in the absence of α-cyclodextrin was 1.2×10−2 min−1. The hydrolysis of an analogous substrate, 2,2,2-trifluoroethyl 3-methyl-4-nitrobenzoate, however, was little affected by α-cyclodextrin, showing that 1 included the cavity of α-cyclodextrin with the nitro group first.
New Type of Active Carbon Catalyst for Simultaneous Removal of SOx, and NOx
Authors: Nishijima Akio , Kurita Minoru , Kiyozumi Yoshimichi , Kobayashi Rikio , Hagiwara Hiroyuki , Ueno Akifumi , Sato Toshio , Todo Naoyuki
Published: July 2006

Active carbons prepared from nitrogen containing compounds were found to show high activity for SO2removal. Enhancement of the activity for NO reduction was realized by supporting vanadium ions on these active carbons. Regeneration of the catalyst was examined with various reducing agents. The activity for SO2 removal was recovered by removing sulfate ions on the catalyst with NH3 at 350 °C. The 200 h life test of the present catalyst was carried out for the simultaneous removal of SOx and NOx.
CO Shift Reaction on the Potassium Polyaluminate Catalyst
Authors: Kihara Seiji , Koumoto Kunihito , Nishikawa Yasuo , Yanagida Hiroaki
Published: July 2006

Potassium polyaluminate (βK″-alumina) has been employed as a catalyst for CO shift reaction (CO+H2O=CO2+H2). The dependence of catalytic activity on the K+ content was investigated. The initial reaction rate abruptly increased above 11 wt% K2O.
The Stereo-differentiating (Asymmetric) Hydrogenation of the C=O Double Bond with a Modified Nickel Catalyst. XXXV. A Facile Method for the Preparation of Optically Pure β-Diols
Authors: Ito Kazuhisa , Harada Tadao , Tai Akira
Published: July 2006

The hydrogenation of RCOCH2COR over a Raney nickel catalyst modified with a mixture of tartaric acid and NaBr gave (R*, R*-RCH(OH)CH2CH(OH)R selectively with a high optical purity. The substrates with R=CH3–, CH3CH2–, CH3CH2CH2–, CH3(CH2)4CH2–, and Ph– were employed in this study. In all cases, the recrystallization of the hydrogenation product gave an optically pure (R*,R*)-isomer which was free from the (R*,S*)-isomer.
The Preparation of Pyrrolotropones from Furotropones
Authors: Takeshita Hitoshi , Chisaka Atsuko , Mametsuka Hiroaki
Published: July 2006

Furotropones were transformed into a series of pyrrolotropones by heating with amines. The methine proton of 1-isopropyl-2-methylcyclohepta[1,2-b]pyrrol-8-one was found to appear at an unusually low field.
The Chemical Shifts of the Bridge Methylene Protons of 1,6-Methano[11]annulene Systems. Positive Evidence for the Assignments
Authors: Uyehara Tadao , Ichida Akito
Published: July 2006

The assignments of the chemical shifts to the bridge methylene protons of 1,6-methano[11]annulen-9-one (3) were established on the basis of their lanthanoid-induced shifting. Those of the protonated cation of 3 were proven from the spectrum of a mixture of 12-d1 derivatives of 3 in trifluoroacetic acid.
A One Step Transformation of a 7-Oxo Steroid into a 7-Oxa Steroid. A New Photo-oxidation of Cyclic Ketone
Authors: Suginome Hiroshi , Shea Chi- Ming
Published: July 2006

Irradiation of 3α,5-cyclo-5α-cholestan-7- one in methanol saturated with oxygen gives a novel cyclo-7-oxa steroid, 3α,5-cyclo-7-oxa-5α-cholestane, together with methyl 3α,5-cyclo-7,8-seco-5α-cholestan-7-oate.
The Acidity and Basicity of Bi2O3-based Binary Oxides
Authors: Ai Mamoru
Published: July 2006

The numbers of both acidic and basic sites in a series of Bi2O3-XnOm binary oxides, with different kinds and amounts of the second component, XnOm, were systematically determined by means of the adsorption of NH3 and CO2 from the gas phase, using the static method. Pure Bi2O3 has both acidic and basic sites, much like TiO2, SnO2, and Fe2O3, and it is more basic than these oxides. The generation of an unexpectedly high acidity or basicity was not observed in the combination of Bi2O3 with 11 kinds of oxides, and the acid-base properties of the binary oxides can be understood in terms of the nature of the second component. The order of ability for the promotion of the acidity and the diminution of the basicity is: MoO3, SO3, WO3>V2O5, P2O5>Sb2O4>TiO2, SnO2, Fe2O3. The addition of K2O decreases the acidity and increases the basicity. The relationship between the acid-base properties and the catalytic activities for the isomerization of 1-butene, the dehydration and dehydrogenation of 2-propanol, and the oxidative decomposition of formic acid was investigated. It was proposed that the basic sites of the Bi2O3based mixed oxides originate from Bi2O3 and that the nature remains approximately the same, regardless of any change in the kind and amount of the second component. However, the acidic sites are generated by the combination with second component; therefore, the nature varies widely depending on the nature of the second component.
Structure Determination of the 1,4-Cycloadduct Quenched after the High-pressure Reaction of Tetracyanoethylene with Styrene and Its Derivatives
Authors: Nakahara Masaru , Uosaki Yasuhiro , Sasaki Muneo , Osugi Jiro
Published: July 2006

The electronic, 13C NMR, 1H NMR, and IR spectra of the 1,4-cycloadducts of TCNE with styrene, styrene-α-d1, p-chlorostyrene, p-methylstyrene, α-methylstyrene, and 1,1-diphenylethylene were taken at low temperatures at 1 bar after the high-pressure reaction; the 13C NMR spectra were of decisive importance in determining the structure; the other kinds of spectra were consistent with the established structure. They have an electronic absorption band around 320 nm, which is assigned to the π-π* transition of the triene system in the adducts. Neither cis- nor trans-stilbene, which have a lower ionization potential, provides the 1,4-cycloadduct even at high pressure.
Kinetics of the Reactions of Ni(II) with Several Ligands in Water-t-Butyl Alcohol Mixtures
Authors: Takahashi Tatsuo , Koiso Takefumi
Published: July 2006

The kinetics of the complex-formation reactions of Ni(II) with 4-phenylpyridine, isoquinoline, 2,2′-bipyridine, 1,10-phenanthroline, and 2,2′: 6′,2″-terpyridine in water-t-butyl alcohol mixtures were investigated by means of stopped-flow measurement. With an increase in the t-butyl alcohol content of mixtures for all ligands, the rate constants for the reactions decrease monotonically, while the activation parameters, ΔHf\eweq and ΔSf\eweq, pass through distinct minimum values, and the minima occur at the same concentration of t-butyl alcohol. The results are briefly discussed in terms of the stability of the outer-sphere complex of Ni(II) with the ligands, and the structural properties of the solvents.
Full-range Bond-order Dependence of Intramolecular Vibrations: Ethylene and Tetracyanoethylene
Authors: Aihara Jun-ichi
Published: July 2006

For analogous normal vibrations in conjugated systems of a similar type a linear relationship often exists between vibrational frequencies and bond orders. We find that this linearity can, in principle, be extended to include conjugated systems in both excited electronic states and ionic states. This indicates that the linearity covers a full range of bond order conceivable for conjugated systems. Such an aspect of molecular vibrations gives a concise and sometimes decisive clue not only to vibrational assignments but also to structural analyses of conjugated systems in various electronic states. Symmetric C=C stretching vibrations of ethylene and tetracyanoethylene nicely illustrate this situation.
Cotton Effect Induced in Optically Inactive Molecules and Molecular Complexes by Optically Active Environment. III. Circular Dichroism Induced by Association of α-Chymotrypsin and Dyes
Authors: I’Haya Yasumasa J , Oikawa Yasunobu , Nakamura Tomoyasu
Published: July 2006

Two types of circular dichroism (CD) spectra are found to be induced in the solution systems of α-chymotrypsin (αCT) and dyes. One is a single positive CD band which is due to a 1 : 1 αCT–dye complex (Type I; proflavine, Acridine Yellow G, acriflavine), and the other consists of one positive and one negative CD bands which are mainly due to a complex of the composition, one αCT to two dye molecules (Type II; Pyronin B, Rhodamine 6G). Mechanisms of CD induction tentatively proposed are that in Type I complexes a single dye molecule is bound to an asymmetric environment of the active site of αCT while in Type II complexes two dye molecules are bound at a specific site exerting a dipole-dipole interaction with one another.
Use of Propagators in the Hückel Model
Authors: Aono Shigeyuki , Nishikawa Kiyoshi
Published: July 2006

The electronic structures of molecules composed of identical atoms are investigated in terms of propagators under the Hückel approximation. General rules to get propagators for systems under considerations are presented. Then some physical quantities (the charge densities, the bond orders and the total energies) are obtained by making the analysis of the propagators. Expressions for the mutual polarizabilities are also exactly derived. Some discussions about the approximate natures of current results are made.
Absorption and Reflection Spectra of Pure and ClSO3H Doped Polyacetylene Films
Authors: Tanaka Masashi , Watanabe Atsushi , Tanaka Jiro
Published: July 2006

Optical absorption and reflection measurements are carried out on pure and ClSO3H doped polyacetylene films over a wide wavelength region (350–35000 cm−1). In the doped polymer, the transition from the valence band to the impurity level is observed at 870 cm−1 and the free carrier absorption band appears over the wide region of 350 to 20000 cm−1, while the interband transition located in the region of 15000 cm−1 disappears. This means that doping removes the bond alternation leading to a uniform bond length and all π-electrons contribute to the transport. For the heavily doped films, the d.c. conductivity of polyacetylene films is obtained by the optimum fit of the theoretical curve to the observed absorption and reflection spectra. The obtained values are comparable with the d. c. conductivity (σ\simeq280–250 Ω−1 cm−1) obtained by the four probe method.
The Preparation and 13C-NMR Spectra of Alkoxymethyltriphenylphosphonium Salts
Authors: Yamamoto Yoshihisa , Kanda Zenjiro
Published: July 2006

Alkoxymethyltriphenylphosphonium salts, [(C6H5)3PCH2OR]X, X: Cl, Br, and I, R: CH3, C2H5, and i-C3H7, have been obtained from the reaction of the triphenylphosphine and the corresponding alkyl halomethyl ether. In the 13C-NMR spectra of these salts, the coupling constant (JCP) is 68–71 Hz, which is larger than that (JCP: 48–56 Hz) of [(C6H5)3PCH2R]Br, R: H, CH3, and i-C3H7, Me3P=S and Me3P=Se, while it is close to that(66–69 Hz) of Me3P=O and Et3P=O. The coupling constant (JCP) of these salts can be caused by the oxygen atom in the salts.
Mass Spectrometric Studies of Some Carboxylic Acid Dimers Produced by a Nozzle Beam: HCO2H, CH3CO2H, C2H5CO2H, and n-C3H7CO2H
Authors: Mori Yoshihiro , Kitagawa Taiji , Yamamoto Tomoki , Yanada Kazuo , Nagahara Shigeru
Published: July 2006

Characteristic ions (M+1)+ and (M+45)+, assigned to be the protonated monomer ion MH+ and (M·CO2H)+ respectively, have been detected in the mass spectrometric measurements of the dimer molecules M2 and the higher clusters Mn of some carboxylic acids produced in their nozzle beams. It has been shown from the dependences of their relative intensities on the stagnation conditions that these ions are mainly formed through the fragmentation of the dimer ions. The MH+ ion plays the most important role in these fragmentation processes of the dimers, while no dimer ion M2+ was observed. These results are discussed in terms of the enthalpy changes for the unimolecular decomposition reactions of M2+.
Electron Spin Resonance Study of Cu(II)–Crown Ether Complexes with 3dZ2 Ground State Doublet in Solution
Authors: Ishizu Kazuhiko , Haruta Tokuhiro , Kohno Yuji , Mukai Kazuo , Miyoshi Kiyonori , Sugiura Yukio
Published: July 2006

Copper(II) chloride and crown ethers (12-crown-4, 15-crown-5 and 18-crown-6) formed orange or orangeyellow complexes in dry chloroform. We found that the ESR g-anisotropy of the complexes was greatly dependent on the numbers of donor oxygens and the ring-numbers. The complexes obtained from 12-crown-4 and 18-crown-6 showed g-anisotropy (g⁄⁄>g⊥); these are well characterized by the 3dx2−y2, or 3dxy ground state. On the other hand, the complexes of 15-crown-5 and its benzo derivatives exhibited the reverse g-anisotropy (g⁄⁄<g⊥); these are characterized by the 3dz2 ground state with S=1/2. The electron nuclear dipolar term and the Fermi’s isotropic term were estimated from the ESR parameters based on Bleaney’s calculation. The chlorine superhyperfine splittings were observed in the g⁄⁄- component. The MO bonding parameters were estimated by assuming the compressed octahedral, the trigonal bipyramidal, and pentagonal bipyramidal geometry at the paramagnetic site. The bonding nature was studied on the basis of the observed ligand spin densities.
The trans-cis Isomerization of the Diaquabis(malonato)chromate(III) Ion in Various Organic Solvent–Water Mixtures
Authors: Uchida Kengo , Takinami Yoshinobu
Published: July 2006

The kinetics of the trans-cis isomerization of [Cr(mal)2(H2O)2]− have been investigated in binary mixed solvents, including methanol-, ethanol-, dioxane-, and acetone-water mixtures. The first-order rate constant increases with a decrease in the volume percentage of the water, but is independent of the kind of organic solvent. The rate is not affected by the addition of any cation to an aqueous solution. These results are in contrast to those for the analogous oxalato complex, and are interpreted in terms of a dissociation mechanism in which the rate-determining step is the dissociation of the coordinating water molecule.
The Stereochemistry and Reactivity of Metal-Schiff Base Complexes. III. The Kinetic and Thermodynamic Stereoselectivities in the Formation of N,N′-Ethylenebis(α-methylsalicylideneaminato)cobalt(III)Complexes with l-Proline, Hydroxy-l-proline, and allo-Hydroxy-l-proline
Authors: Fujii Yuki , Shiono Katsuji , Ezuka Kuniko , Isago Takashi
Published: July 2006

Under air-oxidation conditions, the reaction of [Co(α-Me-sal2en)] with l-aaH, where α-Me-sal2en represents the dianion of N,N′-ethylenebis(α-niethylsalicylideneaniine) and where l-aaH denotes l-proline, hydroxy-l-proline, or allo-hydroxy-l-proline, proceeded rapidly to yield Λ-cis-β2–[Co(α-Me-sal2en)(l-aa)] stereoselectively, followed by the slow isomerization of the Λ-cis-β2-isomer thus formed to give the corresponding Δ-cis-β2-isomer in a yield of almost 100% under equilibrium conditions. The complexes thus formed were isolated and characterized by the use of their absorption, circular dichroism, and 1H-NMR spectra. The preferential formation of the Λ-cis-β2-isomer in the initial reaction was found to be kinetic in origin. The kinetic stereoselectivity was determined to be 87% for l-proline, 56% for hydroxy-l-proline, and 23% for allo-hydroxy-l-proline by the measurement of the rotation at 435 nm of the reaction solutions. On the other hand, no kinetic differentiation was observed for the formation of the similar cis-β2-complexes with l-alanine, l-valine, l-methionine, l-phenylalanine, l-tryptophan, N-benzyl-l-alanine, and N-methyl-l-alanine. On the basis of these data, the mechanism of the initial complexation was discussed. The high thermodynamic stereoselectivity for Δ-cis-β2-isomer was explained in terms of the intramolecular steric interaction between the pyrrolidine ring of the coordinated l-aa and the distorted α-Me-sal2en ligand in the complex.
Configurations of Solvated Complex Ions of First Transition Metals in Hexamethylphosphoric Triamide as Inferred from Their Absorption Spectra and Stokes Radii
Authors: Abe Yuriko , Wada Goro
Published: July 2006

The absorption spectra and Stokes radii of solvated complex ions of first transition metals (Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II)) were observed in hexamethylphosphoric triamide (HMPA) in order to determine their configurations. It seems that the Stokes radii of complex ions are sensitive to the configurational change, since the diameter of an HMPA molecule is very large as compared with the crystallographic diameters of central metal ions. As to the result, metal ions are tetrahedrally solvated in the cases of Mn(II), Fe(II), Co(II), and Cu(II), while in the case of Ni(II), equilibria are established among octahedral, square planar and tetrahedral solvated species. Zn(II) forms probably a complex ion solvated octahedrally by HMPA.
Anodic Stripping Semidifferential Electroanalysis of Mercury(II) at Gold Disk Electrode and Its Application to Environmental Analysis
Authors: Goto Masashi , Ikenoya Kazuhiko , Ishii Daido
Published: July 2006

Anodic stripping semidifferential electroanalysis using a gold disk working electrode was proposed for the trace determination of mercury(II) ion, theoretical predictions being verified. A gold electrode was steeped in aqua regia, activated electrochemically before use, and rotated during the course of pre-electrolysis. A hydroxylamine hydrochloride medium was selected as supporting electrolyte. The detection limit was found to be ca. 0.5 nM under the pre-electrolysis conditions of 10 min at 0 V vs. Ag/AgCl. The relative standard deviation was ca. ±4% for the measurement at 2 nM level. Removal of the oxygen dissolved in sample solutions was not necessary. Experiments were carried out to examine the feasibility of the technique to environmental analysis. The method consists of only the following procedure: sample acidification, standard mercury(II) ion addition, UV irradiation pretreatment, and medium exchange for stripping. It was successfully applied to river water and sea water to separately evaluate ionic mercury, mercury occluded in organic matter, and total mercury (excluding mercury occluded in inorganic matter).
The Reduction of Hexakis(urea)chromium(III) Ions at the Dropping Mercury Electrodes
Authors: Yamada Akifumi , Nakabayashi Yasuo , Yoshikuni Tadatsugu , Tanaka Nobuyuki
Published: July 2006

The polarographic reduction of hexakis(urea) chromium (III) ions at the dropping mercury electrode has been studied in various supporting electrolyte solutions. This complex exhibits two irreversible reduction waves; the first corresponds to Cr(III)→Cr(II), and the second, to Cr(II)→Cr(0). The kinetic parameters of the electrode reactions were determined in various supporting electrolyte solutions and at varied ionic strengths by means of Tast polarography. The differential-pulse polarographic characteristics of this complex are also given.
Preparation and Characterization of Dinuclear Cobalt(III) Complexes Bridged by Quadridentate Ligand with Thioether Donor Atoms
Authors: Yamanari Kazuaki , Shimura Yoichi
Published: July 2006

From the reaction of (2-aminoethanethiolato)bis(ethylenediamine)cobalt(III)(2+) complex with α,ω-dibromoalkanes Br(CH2)nBr, a series of novel monobridged dinuclear cobalt(III) complexes [(en)2Co{NH2(CH2)2S(CH2)nS(CH2)2NH2}Co(en)2]6+ (n=1, 2, 3, 4, 5, 6, 8, and 10) were prepared and characterized on the basis of their absorption, circular dichroism, and infrared spectra and elemental analyses. In the case of n=2, two geometrical isomers, meso and rac, were isolated and identified.
Neighboring Group Participation in the Oxidation of Hydroxy Sulfides. Control of the Reaction Courses and Products
Authors: Ueno Yoshio , Miyano Tadaaki , Okawara Makoto
Published: July 2006

Oxidation of the hydroxy sulfides [PhS(CH2)nCH(OH)R] with hexabutyldistannoxane (HBD)–bromine system was studied in order to clarify neighboring group participation during the course of reaction. The oxidation products were found to be highly dependent on the positions of the two functional groups [sulfide and hydroxyl group]. Thus hydroxy sulfoxides [PhSO(CH2)nCH(OH)R] were obtained as the main product when n=1 or 2, bromo sulfones [PhSO2(CH2)nCHBrR] being predominant when n=3 or 4. Keto sulfoxide [PhSO(CH2)nCOR] was exclusively formed when n=6. The results are discussed in terms of the different intramolecular interactions depending on the positions of the two functional groups.
The Conformations of Several Aliphatic Alcohols. The General Occurrence of the Attractive Alkyl/Phenyl Interaction
Authors: Uzawa Jun , Zushi Shoji , Kodama Yoshio , Fukuda Yoshimasa , Nishihata Ken , Umemura Koshiro , Nishio Motohiro , Hirota Minoru
Published: July 2006

The conformation has been studied, by means of NMR spectroscopy, for diastereoisomeric pairs of a series of alcohols having the following general structure:

CH_3CH(C_6H_5)CH(OH)–R

where R is a methyl, ethyl, isopropyl, or a t-butyl group. It has been demonstrated that the alkyl group (R) is oriented close to the phenyl group in the most preferred conformations; this conclusion is essentially in accord with the results obtained for the structurally related sulfoxides. The general occurrence of an attractive interaction (the CH/π interaction) has, therefore, been suggested between an alkyl and a phenyl group.
Modification of Aminocyclitol Antibiotics. 8. Preparation of 5,6″-Dideoxykanamycin B
Authors: Suami Tetsuo , Nakamura Katsumi
Published: July 2006

In order to obtain an effective antibiotic against a resistant strain of bacteria, two hydroxyl groups on C-5 and 6″ of kanamycin B were removed. 5,6″-Dideoxykanamycin B thus prepared was subjected to antimicrobial tests, its structure being established by mass and 13C NMR spectroscopy.
Nucleophilic Substitution on Dialkoxy Disulfides. III. Reaction with Thioureas
Authors: Kagami Hiroaki , Hanzawa Takashi , Suzuki Nobuo , Yamaguchi Shoso , Saito Masami , Motoki Shinichi
Published: July 2006

1,3- and 1,1-Disubstituted thioureas reacted with diethoxy disulfide to give carbodiimides and 1,2,4-thiadiazoles respectively. 1,1,3-Trisubstituted thioureas and diethoxy disulfide afforded trialkyl(trialkylamidino)thioureas.
Studies of Unusual Amino Acids and Their Peptides. XIII. The Chemistry of N-(Carboxy methyl) amino Acids. II. The Synthesis of Peptides Containing N-(Carboxymethyl) amino Acids
Authors: Miyazawa Toshifumi
Published: July 2006

The basic problems in the synthesis of peptides with N-carboxymethyl(Cm-)amino acids were investigated. Several kinds of N-protected derivatives of a free Cm-amino acid and the N-benzyloxycarbonyl (Z) derivative of its monoester were obtained by the conventional methods used for the parent amino acid. The peptide-bond formation at either carboxyl group of a Cm-amino acid proved to be achievable by the usual methods, such as the carbodiimide, dicyclohexylcarbodiimide–1-hydroxybenzotriazole, or mixed anhydride method, as illustrated by the examples using the Z–Cm-amino acid derivatives as the carboxyl components. On the other hand, a peptide using a Cm-amino acid diester as the amino component could not be prepared by the usual methods mentioned above. The desired compound was eventually obtained by the acid chloride method. A peptide containing a Cm-amino acid with the free imino group was also prepared by the condensation of a bromoacetylated amino acid ester with an amino acid or peptide ester.
The in Situ-generated Nickel(0)-catalyzed Reaction of Aryl Halides with Potassium Iodide and Zinc Powder
Authors: Takagi Kentaro , Hayama Naomi , Inokawa Saburo
Published: July 2006

The in situ-generated nickel(0) species, presumably atomic nickel, from nickel(II) salt and zinc powder has been proved to be an effective catalyst for the Finkelstein-type displacement reaction of aryl bromides with potassium iodide to give aryl iodides under mild conditions. This species was also effective for the Ullmann-type coupling of bromides or aryl iodides by the use of zinc powder to give biaryls. Furthermore, in the presence of excess nickel(II) salt, the coupling reaction proceeded smoothly, even at an ambient temperature, to give various biaryls in very good yields.
Synthesis of 2-Formylazulene and Its Derivatives by Oxidative Cleavage of 2-Styrylazulenes
Authors: Saito Motoyasu , Morita Tadayoshi , Takase Kahei
Published: July 2006

2-Formylazulene and its derivatives were prepared by the oxidative cleavage of styrylazulenes with NaIO4−OsO4. 1,2-Diformyl-, 1,2,3-triformylazulenes, and 5-formylazulene derivative were also synthesized. The reaction of dimethyl 2-methylazulene-1,3-dicarboxylate with p-nitroso-N,N-dimethylaniline in the presence of NaOR (R=Me or Et) gave the corresponding 3-alkoxycarbonyl-2-[p-(dimethylamino)phenyliminomethyl]azulene-1-carboxylic acids followed by hydrolysis with hydrochloric acid to give 3-alkoxycarbonyl-2-formylazulene-1-carboxylic acids. Acetylation of 2-formylazulene-1-carboxylic acids with acetic anhydride gave five membered lactol acetates.
The Effect of Fatty Alcohols on the Dodecane–Water and the Dodecane–SDS Solution Interfaces
Authors: Mieno Fumitake , Ogino Keizo
Published: July 2006

The effects of fatty alcohols (CmH2m+1OH, m=1–12) at the dodecane–water and the dodecane–sodium dodecyl sulfate (SDS)-solution interfaces has been investigated by measuring the interfacial tension and by observing the stability of the emulsion. The following results have been obtained: the addition of lower alcohols (m=1–3) increases the interfacial tenrion at the dodecane–SDS-solution interface, and they are considered as emulsion breakers. With regard to middle and higher alcohols, though, the interfacial tension decreases with the increase in the carbon number. They can thus be used as emulsion stabilizers.
Energy Transfer in γ-Irradiated Cyclohexane–Benzene Mixture Studied by Spin Trapping-ESR Technique
Authors: Doba Takahisa , Nishimura Susumu , Ichikawa Tsuneki , Noda Shoji , Yoshida Hiroshi
Published: July 2006

Cyclohexyl and phenyl radicals were detected in γ-irradiated cyclohexane-benzene mixtures by a spin trapping-ESR technique. The dependence of the radical yields upon mixture composition showed that energy transfer occurs efficiently from cyclohexane to benzene with the transfer efficiency of ca. 0.5 dm3 mol−1.