bluuebunny/crossref_metadata_2025 huggingface dataset:
Dielectric Relaxation and Molecular Structure. XI. Dielectric Behavior of Various Polar Molecules in the Supercooled o-Terphenyl Solution
Authors: Nakamura Masahiko , Takahashi Hiroaki , Higasi Keniti
Published: July 2006

The dielectric constants and losses of dilute solutions of anthrone, xanthone, phenothiazine, 9-fluorenone, benzophenone, diphenylnitrosamine, 1,8-dinitronaphthalene, p-nitrotoluene and m-nitrophenol in o-terphenyl have been measured in the supercooled state in the frequency range 1–100 MHz and temperature range 15–30 °C. The results have been analyzed by Davidson-Cole’s skewed-arc method to calculate the relaxation times, the distribution parameters, the activation enthalpies and entropies for the dielectric relaxation processes.
Spectroscopic and Theoretical Studies on the Protonation to Xanthone Derivatives
Authors: Mizutani Kimiko , Miyazaki Kimiko , Ishigaki Kimiko , Hosoya Haruo
Published: July 2006

Ultraviolet absorption, fluorescence, and excitation spectra of xanthone and its hydroxyl and methoxyl derivatives were measured in sulfuric acid solutions of various acidities. The basicities (pKa’s) of these compounds were obtained from the spectral change. Variable-β type molecular orbital calculations of the π-systems were performed, assignment of the absorption spectra being made. It was confirmed that protonation occurs at the carbonyl oxygen atom. A method for obtaining the equilibrium constant without knowing the absolute intensity is proposed.
High-resolution Photoelectron Spectroscopy of Naphthacene Polycrystal by Means of Helium 21.22 eV Resonance Line
Authors: Seki Kazuhiko , Harada Yoshiya , Ohno Koichi , Inokuchi Hiroo
Published: July 2006

The photoelectron spectrum of naphthacene polycrystal was obtained with a high-resolution photoelectron spectrometer using a helium 21.22 eV light source, and the vibrational fine structures were examined. The resolution, 21 meV FWHM for the argon P3⁄2 peak, became much better than that obtained by means of a retardingpotential-type electron analyzer. Broad peaks with no distinct intramolecular vibrational structure were observed, and the origin of the peak width was discussed.
An MO Calculation of 1,3-Dipolar Cycloaddition between Ethylene and Diazomethane
Authors: Minato Tsutomu , Yamabe Shinichi , Inagaki Satoshi , Fujimoto Hiroshi , Fukui Kenichi
Published: July 2006

A semiempirical SCF MO calculation of the reaction between ethylene and diazomethane was carried out as an example of 1,3-dipolar cycloaddition. A calculation of the interaction energy and electron population by the use of the configuration interaction wave function showed that the formation of the two new bonds in this reaction is concerted but non-synchronous. This result is attributable to the extension of the highest occupied molecular orbital of diazomethane.
Magnetic Susceptibility of Magnesium 2,2′-Dipyridylide in its THF Adducts
Authors: Horiba Tatsuo , Hara Ken-ichi , Inoue Motomichi , Kubo Masaji
Published: July 2006

The magnetic susceptibility of magnesium 2,2′-dipyridylide has been determined in its THF (tetrahydrofuran) adducts in a temperature range of 1.6–20 K. The susceptibility of Mg(dipy)2.THF exhibits two maxima at about 3.9 and 9.5 K due to short range and long-range interactions, respectively. The observed susceptibility conforms to the alternating linear Heisenberg model above about 6 K. Mg(dipy)2·3THF shows no definite maximum of magnetic susceptibility. The magnetic behavior of these complexes different from that of Be(dipy)2 is attributable to the difference in the ionic character between Mg–N and Be–N bonds.
The Reduction of [Ru(Hedta)(H2O)] at the Mercury Electrode and Subsequent Reactions
Authors: Shimizu Kunio , Matsubara Tadashi , Satô Gen P
Published: July 2006

The reduction of [Ru(Hedta)(H2O)] at the mercury electrode and the subsequent chemical reactions in buffer solutions were investigated by AC and DC polarography and by large-scale electrolysis. Two polarographic steps were observed; the more positive step is discussed in this paper. The step was a diffusion-controlled, one-electron reduction of ruthenium(III) to ruthenium(II). For [H+]=(10−3–10−5) mol dm−3 the reduction was reversible, and it became less reversible if [H+]<10−5 mol dm−3. Large-scale electrolysis in formate buffer solutions at the potential of the polarographic diffusion current plateau confirmed that the reduction is a one-electron process. In formate buffer, the reduced form of the complex is deactivated. Furthermore, in the presence of perchlorate ions the reduced form is reoxidized to the original form. The rate constant for the reoxidation reaction at 25.0 °C was k2=(1.38±0.26)×10−3 mol−1 dm3 s−1. The activation parameters for the reoxidation reaction were ΔH\eweq=(94.1±17.6)×103J mol−1 and ΔS\eweq=(19.0±6.3) J K−1 mol−1.
Diels-AIder Reactions of 5,5,5-Trichloro-3-penten-2-one and Related Compounds
Authors: Tsuboi Sadao , Ishiguro Yasuhiro , Takeda Akira
Published: July 2006

The Diels-AIder reaction of 5,5,5-trichloro-3-penten-2-one (1a) with cyclopentadiene afforded exo-2-acetyl-endo-3-trichloromethylbicyclo[2.2.1]hept-5-ene (2a) stereoselectively. The stereochemistry of the reactions of cyclopentadiene with several γ-chlorinated α,β-unsaturated ketones was examined. The endo-directive abilities decreased in the following order: CCl3>CCl2CH3, CHCl2, CCl(CH3)2>CH(CH3)2>CH3. Compound 1a reacted with butadiene and furan to give 4-acetyl-5-trichloromethylcyclohexene (3) and 4-(2-furyl)-5,5,5-tri-chloropentan-2-one (7) respectively.
The Synthesis of 1,3-Thiazines by the Reaction of Non-isolable β-Imino(dithiocarboxylic) Acids with Aldehydes
Authors: Miyauchi Tetsuko , Kadokura Yutaka , Fukada Naoaki , Takeshima Tatsuo
Published: July 2006

1,3-Thiazines, (1)–(6), were synthesized, in yields ranging from 2.9 to 43%, by the reaction of aldehyde with the intermediate β-iminodithiocarboxylic acids which are formed by the reaction of ketones with carbon disulfide in the presence of ammonia.
The Oxyphenylation of Cyclic Olefins Conjugated to the Benzene Ring by Means of Palladium Chloride
Authors: Horino Hiroshi , Arai Mannosuke , Inoue Naoto
Published: July 2006

The reaction of 1,2-dihydronaphthalene, indene, and acenaphthylene with phenylpalladium chloride prepared in situ from phenylmercuric chloride and lithium chloropalladate in aqueous acetone afforded 2-phenyltetrarol, 2-phenylindanol, and 2-phenylacenaphthenol respectively, accompanying by the corresponding phenylated olefins. Acetoxyphenylation products were also obtained in the reactions in acetic acid. The configurations of these oxyphenylated compounds were determined to be trans.
Pyridoxal Model Compounds. I. The Regioselective Formylation of Methoxy-substituted Aromatic Compounds
Authors: Iwata Masaaki , Emoto Sakae
Published: July 2006

9-Substituted 2-methoxyanthracenes (IVa–d) and -triptycenes (Va, b), and 3-substituted anisoles (VIa, b) were formylated by the use of the Vilsmeier-Haack method (Method A) and the metallation method using n-butyllithium (Method B). By the Method A, IVa–c, Vs’, and VIs’ were regioselectively formylated at C-1, C-3, and C-6 respectively, without exception, while by the Method B IVa–c, Va, VIa, and VIb were regioselectively formylated at C-3, C-3, C-2, and C-6 respectively, and Vb gave C-1 and C-3 formylated derivatives in the ratio of 10 to 1 respectively. Possible transition states concerning the occurrence of the regioselectivity were proposed and discussed.
The One-electron Reduction of Carbonium Ions. VI. The Trapping of the Cycloheptatrienyl Radical with 2-Methyl-2-nitrosopropane in the Course of the Zinc Reduction of the Tropylium Ion
Authors: Okamoto Kunio , Komatsu Koichi
Published: July 2006

The zinc reduction of the tropylium ion was carried out in the presence of 2-methyl-2-nitrosopropane (a radical scavenger) in H2O–THF (7:3 by volume) at room temperature. In the reaction mixture with a short reaction time (5 min), t-butyl tropyl nitroxide (II) (a radical-trapping product) was identified by the ESR analysis. α-Phenyl-N-t-butylnitrone (I), which was isolated from the reaction mixture during a prolonged reaction time (30 min), was proved to be derived from the nitroxide II through the hydrogen abstraction by t-butyl nitroxide, which was itself formed from 2-methyl-2-nitrosopropane in situ in the acidic reaction mixture in the presence of zinc powder. The hydrogenation (on Pd/C) of the product mixture for a short reaction time (1 min) gave N-t-butyl-N-cycloheptylhydroxylamine and bicycloheptyl. On the basis of these observations, it is concluded that the primary product of the zinc reduction of the tropylium ion must be the tropyl radical.
Photoinduced Reactions. LXXVII. On the Applicability of Excited Acetone to Induce Photoaromatization of Dihydroheteroaromatics
Authors: Matsuura Teruo , Ito Yoshikatsu
Published: July 2006

Photoaromatization of various dihydroheteroaromatics and some carbocyclic dihydroaromatics with excited acetone was examined. Among the tested compounds, indoline, 2,3-dihydro-2-methylbenzofuran, and 9,10-dihydroanthracene were found to be photoaromatized. 2-Thiazolines, 2-oxazolines, 2-isoxazolines, 9,10-dihydrophenanthrene, 2,3-dihydro-5,6-dimethylpyrazine, 3,4-dihydro-1-methylisoquinoline, and 6-methyl-3(2H)-pyridazinone did not undergo photoaromatization, but recovered unchanged or underwent their own photochemical reactions.
Inositol Derivatives. 7. Azidolysis of Disulfonates of myo-Inositol and 1,2-O-CyclohexyIidene Derivative
Authors: Suami Tetsuo , Ogawa Seiichiro , Oki Shuichi , Sato Haruo
Published: July 2006

Reactions of azide ion with three disulfonates (1,4-, 1,5-, and 1,6-) of myo-inositol and its 1,2-O-cyclohexylidene derivative were studied. The structures of the new azido compounds thus obtained were established by PMR spectroscopy and reaction sequences. The reaction mechanisms of the neighboring-group participation reactions were discussed. Hydrogenation of the azido compounds followed by acetylation afforded the corresponding six inosadiamines as their hexaacetates: three known (allo-1,5, muco-1,3, and myo-4,5) and three hitherto unknown inosadiamines (allo-1,4, muco-1,2, and chiro-2,4).
A Base-induced Elimination Reaction of Phenylsulfonylacetates. I. General Aspect and Stereochemistry
Authors: Sera Akira , Mano Hiroshi , Maruyama Kazuhiro
Published: July 2006

Esters of phenylsulfonylacetic acid were found to undergo a base-induced β-elimination reaction with t-butoxide in t-butyl alcohol. The intervention of a carbanion as an intermediate of the elimination was proposed. The stereochemistry of the elimination was examined by the use of erythro and threo-2-deuterio-1,2-diphenylethyl phenylsulfonylacetates. From the deuterium content in a product, i.e., trans-stilhene, the elimination was found to occur predominantly in a syn fashion.
Spectral Intensities of Some Er3+ β-Diketonate Complexes
Authors: Isobe Toshiyuki , Misumi Seizo
Published: July 2006

The oscillator strengths of the absorption bands of Er3+ acetylacetonate, thenoyltrifluoroacetate, and dibenzoylmethide in methanol and dimethylformamide were determined and discussed in terms of the Judd-Ofelt’s theory. It was possible to use the Judd-Ofelt parameters for the evaluation of the spectral intensities. The oscillator strength of the hypersensitive transition 2H11⁄2←4I15⁄2 of Er3+ complexes, P(2H11⁄2), was indicated by the P(2H11⁄2)≈τcompνcomp U(2)/2J+1 and it is demonstrated that “hypersensitivity” may be explained only by the τ2 parameter of each complex, originating from the forced electric dipole transition.
Fluctuation of the Myoglobin Structure
Authors: Nakanishi Mamoru , Tsuboi Masamichi , Ikegami Akira
Published: July 2006

The kinetics of hydrogen-deuterium exchange in sperm whale metmyoglobin has been followed in aqueous solutions of various pD values (5.6–7.7) and at various temperatures (0–55 °C) by an infrared absorption measurement. At pD=5.6 and at 0 °C, 117 out of the total 148 peptide hydrogen atoms exchange relatively slowly with a rate of an apparent first-order reaction for one hour of the reaction time. This number (117) is almost equal to the sum of the number of peptide NH-groups (108∼111) which are found to be involved in hydrogen bonds with the carbonyls of other peptide groups and those (8) which are in hydrogen bonds with oxygen atoms of some sidechains in the myoglobin molecule in the crystalline state. At higher temperatures and/or at higher pD’s, however, only 109 peptide NH groups (assignable to those involved in the peptidepeptide hydrogen bonds) are found to exchange relatively slowly. The kinetics of the exchange reactions of these 109 peptide NH groups are explained by assuming that the fluctuation amplitude (i.e., the probability of finding the peptidepeptide hydrogen bonds broken) becomes lower on going from the terminus towards the inner portion in each of the eight α-helices involved in the myoglobin structure.
Molecular Structures of Hydrogen Cyanide and Acetonitrile as Studied by Gas Electron Diffraction
Authors: Karakida Ken-ichi , Fukuyama Tsutomu , Kuchitsu Kozo
Published: July 2006

The structures of HCN and CH3CN have been determined by gas electron diffraction for a critical comparison between diffraction and spectroscopic data. For HCN, the rg(C≡N), determined by gas electron diffraction, 1.158±0.003 Å, is consistent within the estimated limit of experimental error with that calculated from the spectroscopic re structure and the harmonic and anharmonic force constants by a perturbation procedure, 1.1588 Å. For CH3CN, electron diffraction intensities have been analyzed jointly with the rotational constants for the normal and three deuterated species determined by microwave spectroscopy by Kessler et al. and Thomas et al. The isotopic difference in the average C–H distance, δr=rav(C–H)–rav(C–D), has also been treated as one of the independent parameters. The analysis has led to the following structure: rg(C≡N)=1.159±0.002 Å, rg(C–C)=1.468±0.002Å, rg(C–H)=1.107±0.004 Å, ∠C–C–H (rav)=109.7±0.2° and δr=0.001±0.002 Å.
Determination of the Number of Hydrogen-Bonds in a Protein Molecule
Authors: Nakanishi Mamoru , Tsuboi Masamichi
Published: July 2006

By means of an infrared-spectroscopic observation of the hydrogen-exchange reaction, the number of peptidepeptide hydrogen-bonds involved in a given protein molecule in its aqueous solution can be determined.
Total Synthesis of Natural Acetylenic Analogues of Isorenieratene and Renieratene
Authors: Ike Tetsuji , Inanaga Junji , Nakano Akio , Okukado Nobuhisa , Yamaguchi Masaru
Published: July 2006

The total synthesis of two natural acetylenic aromatic carotenoids, 7,8-didehydroisorenieratene (1) and 7,8-didehydrorenieratene (2), was carried out. Although the condensations involving C15-acetylenic ylids (derived from the phosphonium salts 7, and 8) as the intermediates gave only 9-cis isomers of 1 and 2, low-temperature condensations of C25-hexaene yield (derived from 19 and 28) with C15-acetylenic aldehyde (12a) led to all-trans  1 and 2, which were identical with natural specimens.
Viscosity B Coefficients for Some Homologous Series of Organic Electrolytes in Aqueons Solutions. The Effect of Ionic Groups
Authors: Tamaki Kunio , Ohara Y\={o}ko , Kurachi Hisashi , Akiyama Mitsuru , Odaki Hirokazu
Published: July 2006

The viscosity B coefficients for the three homologous series of sodium alkane carboxylates (acetate to butyrate), sodium n-alkyl sulfonates (methyl to hexyl), and n-alkylammonium chlorides (methyl to hexyl) in aqueous solutions at 25 °C have been determined. The B values increase linearly with the number of carbon atoms in the alkyl chains for each homologous series studied in this work, as well as for a homologous series of n-alkyl sulfate ions previously studied. In the case of the three kinds of organic anions with the same alkyl groups, the B values increase in the order: –COO−>>–SO3−>–OSO3−. The ion-solvent interaction effect, as estimated by the combination of the B values with the molal volume at an infinite dilution for ions, is positive for each carboxylate ion; however, it is negative for the lower alkyl sulfonate, alkyl sulfate and alkylammonium ions. From these facts, –COO− may be classified as an “electrostrictive structure-maker,” whereas, –SO3−, –OSO3−, and –NH3+ are “electrostrictive structure-breakers.” In this connection, the reported specific interactions of these ionic parts with simple counter-ions on the activity coefficients of organic electrolytes, the counter-ion binding of polyelectrolytes, and the effect of counter-ions on the critical micelle concentrations of long-chain electrolytes are briefly discussed on the basis of the change in water structure induced by both cations and anions in water.
Synthetic Studies by the Use of Carbonates. I. The Nucleophilic Substitution Reaction of Ethylene Carbonate with Amine Hydrohalides
Authors: Yoshino Teruo , Inaba Shigeru , Komura Hajime , Ishido Yoshiharu
Published: July 2006

The reaction of ethylene carbonate with various amine hydrohalides gave the corresponding quaternary ammonium salts of β-hydroxyethylamines in good yields.
Codimerization of Ethylene and Styrene Catalyzed by Bis(triphenylphosphine)σ-Arylnickel(II) Halide–Trifluoroboron Etherate
Authors: Kawata Noboru , Maruya Ken-ichi , Mizoroki Tsutomu , Ozaki Atsumu
Published: July 2006

The codimerization of styrene with ethylene was studied using the catalyst system composed of bis(triphenylphosphine)σ-aryl(bromo)nickel(II) and trifluoroboron etherate in methylene dichloride. The codimerization takes place readily at 0 °C under atmospheric pressure to give 3-phenyl-1-butene selectively. The reaction scheme was discussed on the basis of the product distribution during the course of reaction and its kinetics.
Dehydration of Secondary Alcohols Catalyzed by Solid Acids
Authors: Yamaguchi Tsutomu , Tanabe Kozo
Published: July 2006

In order to examine the correlation between the acidic properties of catalysts and their activity or selectivity and to elucidate the reaction mechanism, dehydration reactions of 4-methyl-2-pentanol and 2-butanol over Al2O3, SiO2, SiO2–Al2O3, ZnS, NiSO4, Al2(SO4)3 or Al2O3 poisoned with basic compounds were carried out at 80–250°C by means of the conventional flow method or a thermal desorption method. The following results were obtained. 1) Both Brönsted and Lewis acids are active, the latter being so to a greater extent. 2) Even relatively weak acid catalysts of acid strength Ho=4.8–6.8 are active, the catalytic activity being correlated with the number of effective acid sites. 3) The selectivity of 4-methyl-1-pentene/4-methyl-2-pentene and 4-methyl-cis-2-pentene/4-methy-trans-2-pentene is lower for Brönsted acids than for Lewis acids and higher for weaker Lewis acid strengths. 4) The composition of butene isomers varies greatly with changes in desorption temperature and the amount of adsorbed 2-butanol in the case of Al2O3, but not much for SiO2–Al2O3. 5) The ratios of cis-2-butene/trans-2-butene and 1-butene/2-butene over Al2O3 are remarkably increased by poisoning with pyridine. A reaction mechanism including a new reaction path has been proposed.
Pressure Effect on the Absorption Spectra of Iron Compounds
Authors: Hara Yoji , Shirotani Ichimin , Sakai Nobuko , Nagakura Saburo , Minomura Shigeru
Published: July 2006

The effect of pressures up to 50 kbar has been measured on the absorption spectra in five ferric compounds, two ferrous compounds, and one mixed valence compound. In six compounds, but not in basic ferric acetate and soluble prussian blue, we observed pressure-induced bands which were assigned to the d-d transition of the converted Fe(II) for the ferric compounds and to the spin-forbidden d-d transition for the ferrous compounds. The absorption spectra for single crystals of potassium ferri- and ferrocyanide were studied at hydrostatic pressures up to 5 kbar. The band-peak intensity decreased with an increase in the pressure in both cases. The charge-transfer band from Fe(II) to Fe(III) of soluble prussian blue showed a blue shift (69 cm−1/kb) at hydrostatic pressures up to 7.2 kbar.
Polarized Absorption Spectra of the Hydroquinone and 1,4-Dimethoxybenzene Crystals in the Near and Vacuum Ultraviolet Regions
Authors: Kaya Koji , Fuke Kiyokazu , Nagakura Saburo
Published: July 2006

We measured the polarized absorption spectra of the γ-hydroquinone and 1,4-dimethoxybenzene crystals in the wave number region between 30000 cm−1 and 65000 cm−1. The dichroic ratios determined for the spectra of both crystals show that the bands at ∼290 nm and at ∼220 nm are polarized parallel with the short and long molecular axes, respectively; these support the assignment that they correspond to the Lb and La bands of benzene, respectively. The dichroic ratios and intensities determined for the bands in the vacuum ultraviolet region show that they do not simply correspond to the Ba,b bands of benzene and that mixing among appropriate excited states occurs in both crystals.
Organic Charge Transfer Salts. III. Photoconductive and Magnetic Properties of Organic Charge Transfer Salts
Authors: Tamamura Toshiaki , Yasuba Hiroshi , Okamoto Kenichi , Imai Tatsuro , Kusabayashi Shigekazu , Mikawa Hiroshi
Published: July 2006

The photoconductive and semiconductive properties of some organic charge-transfer (CT) salts consisting of a pyrylium or thiopyrylium cation and a polycyanoacid anion were investigated in single crystals. The salts are poor semiconductors with a resistivity of 1010–1012 ohm·cm at room temperature, but show relatively large photoconduction when irradiated with monochromatized light in the interionic CT absorption band. There is a strong possibility that the photocarrier is intrinsic in nature, being generated spontaneously from the excited CT state. A weak ESR signal observed originally in these salts increased on the CT band or near IR excitation. From the relationship between the darkcarriers, photocarriers, paramagnetic species and the excited CT state, a mechanism of electrical conduction is proposed in which the carrier generation by the CT interaction and the carrier migration by trapping conduction are involved.
Heterocyclic Azomethine Compounds and Their Reduction Products as Analytical Reagents. II. The Reaction of 1-Picolylideneamino-2-naphthol with Zinc(II)
Authors: Otomo Makoto , Fukui Kiyoshi , Kodama Kazunobu
Published: July 2006

The acid dissociation constants of 1-picolylideneamino-2-naphthol in aqueous dioxane media of various concentrations and the stability constant of the zinc(II) chelate in a 50 v/v% aqueous dioxane medium were determined potentiometrically at 25 °C and μ=0.1. The acid dissociation constants, pKa1, pKa2, and pKa3, at the zero dioxane mole fraction, evaluated by means of a least-squares treatment of the experimental data, are 3.16, 4.31, and 10.31 respectively. The overall stability constant of the zinc chelate was calculated be to logβ2=12.79. 1-Picolylideneamino-2-naphthol can be used as a sensitive reagent for the extractive spectrophotometric determination of zinc. The zinc chelate extracted into chloroform has an absorption maximum at 520 nm. The bathochromic shift is as large as 120 nm. The color system obeys Beer’s law over a concentration range up to 2×10−5M. The molar absorptivity is 4.5×104l/mol·cm at 520 nm.
Transition-metal Complexes of Pyrrole Pigments. IX. Divalent and Trivalent Iron Chelates of Dipyrromethenes
Authors: Murakami Yukito , Matsuda Yoshihisa , Sakata Kazunori , Harada Kenji
Published: July 2006

The iron chelates of polymethyl-substituted dipyrromethenes were prepared. The ferrous ion was found to form complexes having a ligand to metal ratio of 2 : 1 with 5,5′-substituted dipyrromethenes, 3,3′,5,5′-tetramethyl- and 3,3′,4,4′,5,5′-hexamethyl-dipyrromethene. On the other hand, the ferric ion gave a complex having a 3 : 1 molar ratio of ligand to metal with a 5,5′-unsubstituted ligand, 3,3′,4-trimethyldipyrromethene. The complexes were studied by means of visible and IR spectroscopy as well as by magnetic susceptibility measurements. The iron(II) chelates were confirmed to be of high spin type with distorted tetrahedral structure (D2), while the iron(III) chelate demonstrated a low spin character with hexacoordination. The strong ligand-field bands of the latter complex was ascribed to the trigonally distorted octahedral coordination (D3) along with a high covalent nature of metal-ligand bonds.
Peptides. V. Some Carbonates of Ethyl 2-Hydroximino-2-cyanoacetate and Related Compounds as Esterification Reagents for Peptide Synthesis
Authors: Itoh Masumi
Published: July 2006

Some carbonates (III) of ethyl 2-hydroximino-2-cyanoacetate (Ia) and 2-hydroximino-2-cyanoacetamide (Ib) were prepared and utilized as simple esterification reagents for acylamino acids.
Hydroxyl Stretching Frequencies and Conformations of 4-Chromanol, 4-Thiochromanol, and 4-Thiochromanol 1,1-Dioxide
Authors: Hanaya Kaoru , Onodera Shinji , Awano Sachio , Kudo Hideaki
Published: July 2006

Conformations of ten epimeric alcohols have been examined by the measurements of the OH stretching absorptions. The preference of the OH quasi-axial conformations was shown.
The Magnetic Properties of Manganese(II) Phthalocyanine. II
Authors: Miyoshi Hirokazu
Published: July 2006

The magnetic susceptibilities of manganese(II) phthalocyanine (PcMn) have been measured in the paramagnetic region between 13.8 and 280 K. The deviation from the Curie-Weiss law was found at a moderately high temperature (about 70 K), and the Weiss constant was obtained as 23 K. Comparing the ratio of Tc to θ (0.37) with that of the 2- or 3-dimensional lattice, the data were analysed on the basis of the ferro-magnetic linearchain model. The magnitude of the intra-chain interaction (J) was deduced as 5.64k by comparison with Fisher’s classical form of the theory of the ferromagnetic Heisenberg chain. We have also measured the magnetic susceptibilities of cobalt(II) phthalocyanine (PcCo) and of copper(II) phthalocyanine (PcCu), which are isomorphous with manganese(II) phthalocyanine, from 1.8 to 77 K. In PcCo, a broad maximum has been observed, and the data were analysed in terms of the theory of the antiferromagnetic Ising-chain model. On the other hand, PcCu obeyed the Curie law down to 1.8 K. A qualitative explanation of the exchange interactions in PcMn, PcCo, and PcCu was presented on the basis of their electronic states.
Isomerization of 2-Pinene Catalyzed by Solid Acids
Authors: Ohnishi Ryuichiro , Tanabe Kozo , Morikawa Shinsuke , Nishizaki Tadao
Published: July 2006

The isomerization of 2-pinene (I) and 2(10)-pinene (II) in the liquid phase has been studied at 50 °C over solid acid catalysts such as silica–alumina, aluminum phosphate, nickel sulfate and zinc sulfide which have different acid strengths. The primary reaction products were camphene (III), 1,7,7-trimethyl-tricyclo[2.2.1.02,6]heptane (IV) and p-mentha-1,8-diene (VI). The catalytic activities increased with increasing acid strength and acid amount of the catalysts. The selectivities for the formation of III+IV and VI from I were about 90 and 10% respectively over NiSO4, but about 10 and 70% respectively over SiO2–Al2O3 and AlPO4. Those for the formation of I, III+IV and VI from II also depended on the acid strength. In the isomerization of VI, p-mentha-1,4(8)-diene (VII) was formed predominantly over NiSO4 and p-cymene (IX) over SiO2–Al2O3. From these results together with those of the isomerizations of III and IV, a reaction mechanism is proposed which consists of two parallel reactions proceeding via a common intermediate between I and II: one which gives monocyclic terpenes and the other bi- and tricyclic terpenes.
A Reinvestigation of the Normal Vibrations of Thioacetamide
Authors: Ray Arabinda , Sathyanarayana D N
Published: July 2006

The normal coordinate treatments of thioacetamide and its seven isotopic molecules have been carried out using Urey-Bradley force constants refined by a least-squares procedure. The laser Raman spectrum of thioacetamide has also been recorded.
Studies on Preparation of High Purity Sulfur. IV. Effect of the Distillation with Adsorbent and Silver on the Removal of the Impurities in Sulfur
Authors: Suzuki Hiroshi , Higashi Kunishige , Miyake Yoshizo
Published: July 2006

The distillation was shown to be effective in removing arsenic, selenium, tellurium, carbon, and common elements in sulfur. However, there was the disadvantage that trace amounts of common elements were not reduced further by the repetition of the distillation. This could be carried out by the zone refining.
Direct Syntheses of Methyl 2-Deoxy-2-alkoxycarbonylamino-d-glucopyranoside from 2-Amino-2-deoxy-d-glucose
Authors: Otani Sinichi
Published: July 2006

Methyl 2-deoxy-2-methoxycarbonylamino-and methyl 2-deoxy-2-ethoxycarbonylamino-d-glucopyranosides were synthesized by the reaction of 2-amino-2-deoxy-d-glucose with alkyl chlorocarbonate and sodium carbonate in methanol by a one-step process.
The Gas Chromatographic Determination of Selenium in Plant Material with 4-Nitro-o-phenylenediamine
Authors: Shimoishi Yasuaki
Published: July 2006

Selenium(IV) reacts with 4-nitro-o-phenylenediamine to form 5-nitropiaselenol, which is detected by means of a gas chromatograph equipped with an electron-capture detector. By this highly sensitive method, the determination of very small amounts of selenium in plant materials has been investigated. Fuming nitric acid digests the plant sample completely, and the selenium is converted to the quadrivalent state. No loss of selenium can be found by this treatment. A method is proposed for the determination of selenium in plant materials at levels as low as 0.005 μg/g in dried material.
Solvent Extraction Equilibria of Acids. VII. The Co-extraction of Water with Strong Mineral Acids by Trioctylphosphine Oxide
Authors: Niitsu Masaru , Iritani Nobuhiko , Sekine Tatsuya
Published: July 2006

The extraction of water from a 1 mol dm−3 sodium perchlorate solution with trioctylphosphine oxide (TOPO) in four organic solvents and the co-extraction of water with hydrochloric, hydrobromic, hydroiodic, perchloric, nitric, and thiocyanic acids from 1 mol dm−3 of the acid solution by TOPO in hexane have been studied at 25 °C. The extraction constants of water in the absence of any of the acids, K′H2O=[TOPO·H2O]org[TOPO]org−1, were determined to be 100.40, 100.00, 10−0.12, and 10−0.36 in benzene, hexane, carbon tetrachloride, and chloroform respectively. A discrepancy from the 1: 1 molar ratio of TOPO and water in the extract was observed in the higher-TOPO-concentration region in the hexane system. The co-extraction of water with the acids disolvated by TOPO was greater in the order of HCl\simeqHBr>HI>HClO4, and it was much poorer with the monosolvated acids, nitric and thiocyanic acid. The equilibria for these co-extractions of water with the acids are complicated.
Molecular Weight Distribution and Kinetics of Low-temperature Propene Polymerization with Soluble Vanadium-based Ziegler Catalysts
Authors: Doi Yoshiharu , Takada Morio , Keii Tominaga
Published: July 2006

A kinetic study has been carried out on the low-temperature polymerization of propene with the soluble catalyst system, VCl4 and alkylaluminium (AlEt2Cl, AlEt2Br, or AlEt3). The rate coefficients of the elementary reactions were evaluated at −78 °C. The molecular weight distribution function was derived on the basis of the polymerization mechanism. The theoretical distribution curves and experimental distribution curves obtained by use of a gel permeation chromatography agree, supporting the mechanism proposed for the coordination polymerization.
Acidic Property and Oxidation Activity of MoO3-V2O5-P2O5 Ternary Oxides
Authors: Ai Mamoru
Published: July 2006

The relationship between the acid-base properties and the oxidation activity of a series of ternary oxide catalysts, MoO3–V2O5–P2O5, with different V/Mo composition and a constant phosphorus content, P/(Mo+V)=0.1, was investigated. The acidity was determined by means of the NH3 adsorption and by studying the catalytic activity for acid-catalyzed reactions, such as dehydration of isopropyl alcohol and isomerization of 1-butene, in the presence of an excess of air. A new acidic site is generated by the combination of two binary oxides, i.e., MoO3–P2O5 and V2O5–P2O5, and a broad maximum in the acidity occurs at V/(Mo+V)=0.4–0.9. The basic property is so small that no satisfactory data can be obtained from the adsorption of acidic molecules such as CO2, SO2, and acetic acid. The catalysts, regardless of composition, are inactive for reactions which are accelerated by basic sites, such as oxidative dehydrogenation of isopropyl alcohol to acetone, oxidative decomposition of formic acid to CO2, and oxidation of methanol to CO2. The oxidation activities for butadiene and methanol can be tied to the acidity of the catalysts.
Molecular Dynamics of Polystyrene Model Molecules; Reorientational Correlation Times of Phenyl Groups of 2,4-Diphenylpentane
Authors: Koda Shinbu , Nomura Hiroyasu , Miyahara Yutaka
Published: July 2006

The reorientational correlation times of phenyl groups in 2,4-diphenylpentane in solution were measured as a function of the temperature by means of Raman line-shape analysis. The reorientational correlation times of both isomers increase as the temperature increases, that is, the reorientational motion of phenyl groups in molecules gradually become active. In the low-temperature region, the reorientational correlation times of the meso 2,4-diphenylpentane are longer than those of the racemic one. This fact that the molecular motion of phenyl groups of the racemic isomer rotates more easily than that of the meso one is in agreement with the results obtained from ultrasonic study by Monnerie et al. On the other hand, in the higher-temperature region, the reorientational correlation times of the meso isomer are shorter than those of the racemic one. In addition, the potential barriers for the reorientational motion of phenyl groups are found to be (3.3±0.3) kcal/mol for the meso isomer and (2.0±0.3) kcal/mol for the racemic isomer.
Studies of the Separation Mechanism in Ion-exchange Chromatography. I. Inversion of the Elution Order of cis and trans Isomers of Metal Complexes
Authors: Yoneda Hayami , Yamazaki Shigeo
Published: July 2006

The inversion of the elution order in ion-exchange chromatography was found for cis and trans isomers of [Co(X)2(en)2]+ (X=N3−, NO2−, and NCS−) by the addition of dioxane to NH4Cl or (NH4)2SO4 aqueous solution as eluent, and the separation mechanism was discussed.
EPR Studies of the Cobalt(II)–(N2S2)-Schiff Base Complex with Lewis Bases and CO
Authors: Sakurada Matsujiro , Sasaki Yoshihiro , Matsui Masakazu , Shigematsu Tunenobu
Published: July 2006

The EPR and optical spectra of N,N′-bis-3-thioxo-1-methylbutylidene)ethylenediaminatocobalt(II) in the presence of Lewis bases and CO were measured. The cobalt(II) complex formed five-coordinate adducts with Lewis bases and CO, which had a rhombic symmetry with a (dx2−y2, dxz, dyz)6(dz2)1 ground configuration.
The Carbonylation of α-Haloacetophenones and Benzyl Halides by Disodium Tetracarbonylferrate
Authors: Watanabe Yoshihisa , Taniguchi Kenichi , Suga Masataka , Mitsudo Take-aki , Takegami Yoshinobu
Published: July 2006

α-Haloacetophenones and benzyl chlorides can be converted into derivatives of β-keto acid and phenylacetic acid respectively by two succesive reactions, with Na2-Fe(CO)4 and then with nitrobenzenes or iodine-ethanol as the oxidizing reagents.
Preparation of 1,3-Bis(4-aminobutyl)-1,3-dimethyl-1,3-diphenyldisiloxane and Siloxane-containing Polyamides
Authors: Takiguchi Toshio , Amagai Kazuo , Kawabata Hisashi
Published: July 2006

1,3-Bis(4-aminobutyl)-1,3-dimethyl-1,3-diphenyldisiloxane has been readily obtained by the reduction of 1,3-bis(3-cyanopropyl)-1,3-dimethyl-1,3-diphenyldisiloxane, the hydrolysate of chloro(3-cyanopropyl)methylphenylsilane. The diamine reacted with abietic acid forming an equimolar crystalline adduct which gave a siloxane-containing polyamide by the conventional salt fusion technique.
A Convenient Method of Preparing p-Toluenesulfonates of Ethyl Esters of Amino Acids Using Ethyl p-Toluenesulfonate
Authors: Ueda Kazuo
Published: July 2006

The treatment of amino acids with ethyl p-toluenesulfonate affords the p-toluenesulfonates of the ethyl esters in good yields. Tryptophan ethyl-ester p-toluenesulfonate was also prepared in an 81% yield.
14N Nuclear Quadrupole Relaxation in Sulfuric Diamide and Methanesulfonamide
Authors: Negita Hisao , Kubo Tsuneo , Maekawa Michio , Ueda Akinobu , Okuda Tsutomu
Published: July 2006

The 14N nuclear quadrupole resonances (NQR) in sulfuric diamide (sulfamide), H2NSO2NH2, and methanesulfonamide, CH3SO2NH2, were studied by the pulse method. The resonance frequency and the spin-lattice relaxation time (T1) were measured in the temperature range from liquid nitrogen temperature to room temperature. In the case of sulfuric diamide, T1 decreases monotonously as the temperature rises, and is dominated by the thermal torsional motion below 140 K. On the other hand, T1 is attributed to the reorientation of the amino group in the temperature range from 200 to 240 K, whereas it is due to the reorientation of the molecule above 240 K; the activation energies in these orientations are 43.5 and 61.5 kJ·mol−1 respectively. In the case of methanesulfonamide, the minimum of T1 is found near 130 K. This is caused by the rotation of the methyl group. The activation energy for this motion is calculated to be 9.6 kJ·mol−1. The dominant relaxation mechanism is attributed to the reorientation of the amino group from 200 to 240 K and to the reorientation of the molecule above 240 K. The activation energies for these motions are 19.2 and 40.6 kJ. mol−1 respectively.
Ultrasonic Absorption in Dodecane Solution of Aerosol OT
Authors: Yamashita Teruyo , Yano Hiroshige , Yasunaga Tatsuya
Published: July 2006

The ultrasonic absorptions of Aerosol OT in dodecane solution were measured in the frequency range 5–95 MHz at various temperatures. An excess absorption caused by single relaxation was observed above the second critical micelle concentration. This is attributed to the conformational change in structure of two kinds of Aerosol OT micelles, since the maximum excess absorption per wave length depends on the concentration and temperature. The thermodynamic and kinetic parameters were determined in relation to the reaction.
Intramolecular Charge-transfer Absorption Spectra of Tetracyanotetrathiafulvalene
Authors: Yoneda Shigeo , Kawase Tokuzo , Yoshida Zen-ichi
Published: July 2006

The electronic spectrum and structure of tetracyanotetrathiafulvalene have been investigated by the ASMO-SCF-CI method, in which the 3d orbitals of sulfur atoms are taken into account. The calculated results showed that the absorption band at the longest wavelength can be interpreted in terms of intramolecular charge-transfer.
The Determination of the Chemical Diffusion Coefficients for AgBr and α-Agl by Means of an Improved d.c. Polarization Cell
Authors: Mizusaki Junichiro , Fueki Kazuo , Mukaibo Takashi
Published: July 2006

In order to determine the chemical diffusion coefficients for AgBr and α-AgI, a new experimental technique was developed. A Pt probe was inserted into the middle of the AgX (X=Br or I) pellet in an improved d.c. polarization cell of the Ag/AgX/carbon type, and the applied potential difference between the Ag and carbon electrodes was changed abruptly. The accompanying change in E(L⁄2), the EMF between the Ag electrode and the Pt prcbe, was followed, and the cherrical diffusion coefficient, \ ildeD, was determined by the analysis of the change in E(L⁄2) with the time. In the temperature range from 325 to 400 °C, \ ildeD for AgBr with excess silver was found to be

\ ildeD=7.10×102exp\left(−\frac1.96×104 cal molRT\ight)cm2s−1. (i)

In the temperature range of 330 to 500 °C, \ ildeD for a-AgI was

\ ildeD=4.95×10−1exp\left(−\frac7.71×103 cal mol−1RT\ight)cm2s−1. (ii)

Using these chemical diffusion coefficients and the electronic conductivity data, the nonstoichiomctry, and apparent mobility of electronic carriers of AgBr and α-AgI were determined.
Adsorptive Mechanism on Activated Carbon in the Liquid Phase. I. Free Energy Change for Adsorption of Organic Compounds from Aqueous Solution on Activated Carbon
Authors: Abe Ikuo , Hayashi Katsumi , Kitagawa Mutsuo , Urahata Toshihiro
Published: July 2006

The adsorption isotherms, from aqueous solution onto activated carbon, have been determined for the 22 aliphatic monofunctional compounds; alcohols, carboxylic acids, ketones, ethers, esters, and aldehydes. The free energy change for the adsorption process has been calculated from the adsorption equilibrium constant at infinite dilution; a linear relationship exists between the free energy change and the number of carbon atoms in the solute. The free energy of adsorption has been divided into two contributions: the hydrocarbon and the functional group contribution. The free energy change for the adsorption process has been compared with the free energy change for the precipitation process from solution into the pure liquid solute. The free energy contribution per individual methylene group to the adsorption process shows an approximate agreement with that for the precipitation process indicating that the adsorption process of the hydrocarbon portion of the solute is analogous to the precipitation process. The free energy contribution of the functional group to the adsorption process is smaller than that for the precipitation process indicating that the functional group portion of the solute is not appreciably dehydrated in the adsorption phase.
The Study of Carrier Effects on the ESR of Vanadium Ions Formed in Supported Catalysts, as Assisted by Spectrum Calculation
Authors: Ueda Hisashi
Published: July 2006

In order to study the carrier effects on the supported catalysts of vanadium, the ESR spectra of vanadium ions supported on γ-Al2O3, SiO2, ZrO2, TiO2, MgO, or CaO and reduced in H2 at 500 °C were studied. When γ-Al2O3, SiO2, ZrO2, or TiO2 were used as the carriers, the main spectral component could be assigned to the V4+ ion. The results of data analysis, assisted by spectrum calculation, showed that, on catalyst which had a high activity in the reduction of NOx by NH3, the V4+ ion had a highly populated dxy orbital, while on catalyst of low activity, V4+ had a dxy with a low spin density. If the carrier was MgO, the V ion was reduced to V2+. If the carrier was CaO, no ESR signals due to V ions were observed. It has been suggested that an inhomogeneous and axially symmetric crystal-field model may interpret the intensity ratios among the hyperfine lines of the V4+ ESR absorption rather than a non-axial symmetry model of the V4+ unpaired electron.
Effect of Methyl Substitution on the Electron Spin Resonance Spectra of Yang’s Biradical
Authors: Mukai Kazuo
Published: July 2006

Mono- and dimethyl derivatives (II) and (III) of Yang’s biradical (I) were prepared, and the methyl-substitution effects on the molecular symmetry and spin-density distribution of Yang’s biradical have been studied. Resolved hyperfine structures were observed in the ESR spectra of liquid solutions of the biradicals (II) and (III), giving the hyperfine splitting values theoretically expected for their triplet states. In a fluid solution, the biradical molecules retain a three-fold symmetry, as has been reported for Yang’s biradical, and the expected methyl-substitution effect is too small to induce any asymmetric, unpaired spin distribution. The g- and D-tensor values of the (II) and (III) biradicals were determined from analyses of the asymmetric ESR spectra of frozen solutions containing the biradicals. The results suggest that these biradicals must also lack a three-fold symmetry in a frozen solution, as has been observed for Yang’s biradical. Essentially the same g- and D-tensor values as those of Yang’s biradical are observed for the monomethyl derivative (II). On the other hand, the dimethyl derivative (III) shows quite different g- and D-tensor values.
The Combined Field Emission-Spin Trapping Method for Studying Reactions of Electrons in Organic Solutions
Authors: Noda Shoji , Ohta Yasunari , Yoshida Hiroshi
Published: July 2006

The reactions of electrons injected by field emission into solutions have been investigated. Free radicals generated by the dissociative electron attachment to chlorinated solutes in benzene solutions were detected by the spin trapping-ESR method, using pentamethylnitrosobenzene as a spin trapping agent. Nondissociative electron attachment to styrene caused by the field emission was also evidenced by detecting the α-methylbenzyl radical generated secondarily from the styrene radical anion. The electrons field-emitted into the solutions are captured almost quantitatively by the electron scavenging solutes. The field emission method has been found to be useful for generating authentically free radicals and for studying the anionic reaction induced by electrons without interference of countercations and of any reaction intermediates from solvent molecules. As an example of the chemical utilization of the field emission technique, the ESR parameters of the spin adducts of several hydrocarbon radicals have been collected by this technique.
ESR Study of Molecular Oxygen Anion Radicals Produced on Cation-exchanged X-Type Zeolites by γ-Irradiation
Authors: Kanzaki Natsuko , Yasumori Iwao
Published: July 2006

Molecular Oxygen anion radicals (O2−) were produced on X-zeolites by γ-irradiation in the presence of O2. Their properties were systematically investigated by means of ESR spectroscopy. Two kinds of O2− species with different gz values were formed on monovalent cation-exchanged (LiX, KX, RbX, CsX) zeolites and MgX, while three and single O2− species were observed on divalent cation-exchanged (CaX, SrX, BaX) and trivalent cation-exchanged (LaX) zeolites, respectively. These O2− radicals showed different reactivities with N2O or 1-butene, and their gz values were classified into four groups. By considering the results from the gz values and the effect of introduced high pressure O2 on the O2− spectra, the adsorption sites for the radicals on zeolites were determined.
Antiferromagnetic Spin-exchange Interaction in Mixed-spin Trinuclear Cobalt(II) Complexes with Quadridentate Schiff Bases
Authors: Kasempimolporn Visit , Okawa Hisashi , Kida Sigeo
Published: July 2006

Trinuclear cobalt(II) complexes, [Co(R1R2-L)]2CoX2 (R1 R2=H, Me; L=en, ch, ph; X=Cl−, Br−), have been synthesized, where H2(R1,R2-L) denotes the Schiff bases obtained by condensing a 5(R1), α(R2)-substituted salicylaldehyde with a diamine (H2N-L-NH2) in a 2:1 mole ratio. From IR spectra and cryomagnetic properties, it was concluded that these complexes are in mixed-spin state of a Co(II)(s=l/2)-Co(II)(s=3/2)–Co(II)(s=l/2) system, strong antiferromagnetic spin-exchange interaction operating between low-spin and high-spin cobalt(II) ion via dπ(low-spin Co)-pπ(O)-dπ(high-spin Co) super pathway.
The Revised Structure of Dispermol and Total Synthesis of Maytenoquinone, Dispermol, and Dispermone
Authors: Matsumoto Takashi , Ohmura Taishi , Usui Shuji
Published: July 2006

Condensation of β-cyclocitral with 2-isopropyl-3,4-dimethoxybenzyl chloride afforded an alcohol (15) which was converted into (±)-12,13-dimethoxytotara-8,11,13-trien-6-one (18). Demethylation of (±)-18 followed by air oxidation gave (±)-maytenoquinone. Reductive cleavage of the hydroxyl group in (±)-15 produced a phenethyl derivative which was cyclized to give (±)-12,13-dimethoxytotara-8,11,13-triene (23) and its cis-isomer (24). Oxidation of (±)-23 with chromium trioxide, followed by demethylation of the resulting 7-oxo compound (25), afforded (±)-dispermone. The Wittig reaction of (R)-(−)-α-cyclocitral with 2-isopropyl-3,4-dimethoxybenzyltriphenylphosphonium chloride yielded a styrene derivative. This was partially hydrogenated and then cyclized to give (+)-23 and (−)-24. The trans-isomer (23) was converted into (−)-dispermone (3) via (−)-25 and also partially demethylated to (+)-12-methoxytotara-8,11,13-trien-13-ol (2), the proposed structure for dispermol. Since the synthetic (+)-2 was not identical with the natural compound, (−)-3 was then converted into (+)-13-methoxytotara-8,11,13-trien-12-ol, which was identical with natural dispermol. (−)-25 was also converted into (+)-maytenoquinone.