bluuebunny/crossref_metadata_2025 huggingface dataset:
Low Frequency Bands and Barrier to Internal Rotation in Pentafluoroethane
Authors: Kinumaki Susumu , Kozuka Muneteru
Published: July 2006

The infrared absorption spectra of gaseous and liquid CF3CHF2 were examined in the region from 500 to 60 cm−1. The Raman spectrum of the liquid at room temperature was also photographed. In the gas-phase spectrum, bands were observed at 414, 363, 306, 246, 216 and 82 cm−1. The contour of the medium-intensity band at 82 cm−1 was consistent with that to be expected for torsional oscillation. This frequency would correspond to a triple cosine barrier of 4.4 kcal/mol.
The Polarized Absorption Spectra of Solid Molecular Compounds of Chloranil and Aromatic Amines
Authors: Amano Takako , Kuroda Haruo , Akamatu Hideo
Published: July 2006

The polarized absorption spectra of the single crystal were observed for six molecular compounds which involve chloranil as the electron acceptor and aromatic amines as the electron donor. The molecular compounds of N,N-dimethylaniline, 1-naphthylamine, and N,N-dimethyl-2-naphthylamine have a non-ionic ground state. In these cases, the locations of the charge-transfer bands in the crystal spectra are similar to those of the corresponding bands of the 1 : 1 molecular complexes formed in the solution. The solid molecular compounds of p-phenylenediamine, N,N,N′,N′-tetramethyl-p-phenylenediamine, and diaminodurene can be regarded as ionic crystals composed of the positive ion of the donor and the negative ion of the acceptor. In these cases, the absorption bands associated with the component ions are observed in the crystal spectra, but they are broadened and appreciably shifted to a higher energy as compared with the case of the solution spectra of the ions. The absorption band associated with the charge transfer between ions is observed in the near-infrared region of the crystal spectra of these molecular compounds.
The Reaction between Mercury(II) and Organic Compounds. IV. A Photometric Method for the Determination of Basic Amino Acids Precipitated with a Mercury(II) Perchlorate Precipitant and Some Properties of Their Products
Authors: Kai Fumiaki
Published: July 2006

The particular reactivity of basic amino acids in presence of mercury(II) perchlorate gives white amorphous products (by X-ray powder diffraction). The structures of the products may be considered to be [Arg-Hg]ClO4·Hg(ClO4)2, [His-Hg]ClO4·Hg(ClO4)2 and [Lys-Hg]ClO4·Hg-(C1O4)2 on the bases of elemental analytical data and of infrared patterns showing the absorption bands of νas(Hg–O), ν(Hg–N) and perchlorate ions. The applicability of this peculiar reactivity to the separation and photometric determination of basic amino acids has been studied. The above mentioned products were obtained selectively as a mixture from a mixture of about twenty kinds of amino acids. The isolation of the mixture into each product could be performed satisfactorily by utilizing the different solubilities of the products in 10 n acetic acid containing sodium or potassium chloride (3.3 W/V %), and in an aqueous sodium hydroxide solution. Although the products showed characteristic ultraviolet absorption curves differing from those of the components, there were no absorption maxima in any case. The calibration curves, which followed Beer’s law, could be obtained at any proposed wavelength. By using the calibration curves thus obtained, a very small amount of each basic amino acid could be determined spec-trophotometrically in the 220–250 m/μ region, within detection limits of about 10−5–10−4m. Constant absorbancies could be attained in the pH range of 1.5–10.7 of the sample solutions.
Catalytic Dehydrogenation of Secondary Alcohols with Reduced Copper. VI. The Dehydrogenation of Isopropyl Alcohol (Part III)
Authors: Kawamoto Kazuaki , Nishimura Yoshiharu , Hiraki Teruo
Published: July 2006

In order to determine whether the condensing activity of reduced copper is affected by the mode of preparation of the catalyst, the condensation of isopropyl alcohol to isobutyl methyl ketone, diisobutyl ketone, and isobutylmethylcarbinol was studied with catalysts prepared in different ways. It was found that the copper catalyst obtained by the hydrogen treatment of the oxide prepared from copper nitrate and an excess of sodium hydroxide was the most suitable catalyst for the condensation of isopropyl alcohol to isobutyl methyl ketone and diisobutyl ketone, and that the copper catalyst prepared with potassium carbonate was the most suitable catalyst for the dehydrogenation of isopropyl alcohol to acetone with no side reaction.
Asymmetric Hydrogenation with Modified Raney Nickel. IX
Authors: Izumi Yoshiharu , Tanabe Tadashi , Yajima Shinichi , Imaida Masami
Published: July 2006

The asymmetric hydrogenation catalysts were prepared from the Raney nickel catalyst by modifying it with ls-3,3-dimethyl-2-hydroxybutyric acid and the corresponding amino acid, l-t-leucine, which have most methyl groups at the β-position. The asymmetric activities of the catalysts were measured by the hydrogenation of the methyl acetoacetate to methyl 3-hydroxybutyrate. The asymmetric activity of the catalyst modified with an aqueous solution of ls-3,3-dimethyl-2-hydroxybutyric acid was very low, and the direction of asymmetric activity at pH 5.0 was inverted by the temperature of the modifying solution. However, there was a high asymmetric activity in the catalyst modified with l-t-leucine, and this activity was not so influenced by the temperature of the modifying solution. The aysmmetric activities of catalysts modified with α-hydroxy acids and the corresponding amino acids reported in this paper and the previous papers are compared, and the effect of the bulk of the α-alkyl substituent of the modifying reagent upon the asymmetric activity of the catalyst is discussed.
Stereochemical Studies of Monoterpene Compounds. III. Stereochemistry and Intramolecular Hydrogen Bonding of 1-Hydroxy-p-menth-3-en-2-one and Its Reduction Products
Authors: Suga Takayuki , Shishibori Tsuyoshi , Matsuura Tamon
Published: July 2006

1-Hydroxy-p-menth-3-en-2-one (1) was prepared from α-terpinene by the t-butyl chromate oxidation, trans- and cis-p-Menth-3-ene-1,2-diols (4 and 5), 1-hydroxyisocarvomenthone (2), and 1-hydroxycarvomenthone (3) were also prepared from the compound 1 by lithium aluminum hydride reduction or by hydrogenation. The configurations of these compounds, 1–5, were identified on the basis of chemical evidence, and then the preferred conformation was determined by infrared spectroscopy on the basis of the conception of intramolecular hydrogen bonding. 1 and 2 were found to exist predominantly in the hydrogen-bonded conformations, 1a and 2a, respectively. With respect to 3, the existence of the conformational equilibrium, 3a\ightleftharpoons3b, was demonstrated by the presence of the free and bonded hydroxyl bands. Moreover, 4 and 5 were proved to take the preferred conformations of 4a and 5a respectively.
Studies on Isothiazoles. III. A Novel Ring Closure to Isothiazoles by the Reaction of α-Amino Ketones with Thionyl Chloride or Sulfur Monochloride
Authors: Naito Takayuki , Nakagawa Susumu , Okumura Jun , Takahashi Kiyoshi , Kasai Ken-ichi
Published: July 2006

New compounds, 4-hydroxyisothiazoles, have been prepared by the reaction of α-amino ketones with thionyl chloride or sulfur monochloride, which is a novel procedure for cyclization to an isothiazole ring. Polar solvents, especially dimethylformamide (DMF), were preferable for this cyclization. The reaction hardly proceeded in a nonpolar solvent such as benzene, but was accelerated by an addition of a small amount of DMF.
The Structures and the Reactions of Acetyl- and Benzoylacrylic Acids and Their Esters
Authors: Sugiyama Noboru , Gasha Taketoshi , Kataoka Hiroshi , Kashima Choji
Published: July 2006

The Structures and properties of α,β-unsaturated γ-oxo acid, acetyl- and benzoylacrylic acid, and their esters are studied.
Selective Cleavage of Serine Peptides
Authors: Kaneko Takeo , Takeuchi Ikuko , Inui Toshishige
Published: July 2006

The treatment of N-benzyloxycarbonyl-l-alanyl-l-serine methyl ester (I) with phosgene afforded the corresponding O-chlorocarbonyl derivative (II), which was then cyclized to methyl l-3-(N-benzyloxycarbonyl-l-alanyl)-2-oxo-oxazolidine-4-carboxylate (III) accompanied with N-benzyloxycarbonyl-l-alanyl-3-chloro-l-alanine methyl ester (IV) by refluxing in xylene. By the mild alkaline hydrolysis of III, N-benzyloxycarbonyl-l-alanine and l-2-oxo-oxazolidine-4-carboxylic acid (V) were isolated as a result of the selective cleavage of the peptide bond in which an amino group of the serine residue participated. This method was also applied to three other serine peptides; the same results were obtained.
The Acid-catalyzed Bromination of Aromatic Compounds with Potassium Bromate in Aqueous Acetic Acid
Authors: Furuya Yoshiaki , Morita Atsushi , Urasaki Iwao
Published: July 2006

Bromobenzene is obtained in a 64% yield when an aqueous acetic acid solution containing a catalytic amount of sulfuric acid is slowly added to an aqueous acetic acid solution of benzene and potassium bromate at 60°C. It seems, according to the synthetic data, that the formation of bromobenzene is accelerated by an electron-releasing group. The rate of the consumption of active oxygen has been expressed as follows:

v=k_2[BrO_3^-][C_6H_6]+k_3[BrO_3^-][C_6H_6]^2

Here, both k2 and k3 gave a straight line against −log(CBH+⁄CB), with a slope of ca. −2. The reaction is accelerated by sulfuric acid and does not occur at all in the absence of the acid. The evolution of oxygen gas was not observed during the reaction, but the presence of peroxyacetic acid and/or acetyl peroxide in the reaction mixture was indicated by paper chromatography. A mechanism which involves the rate-determining attack of protonated hypobromous acid and/ or protonated acetyl hypobromite on benzene has been suggested.
On the Viscosity of Liquid Selenium
Authors: Hamada Shuichi , Yoshida Naosato , Shirai Toshiaki
Published: July 2006

The viscosities of liquid selenium and partially-chlorinated liquid selenium were measured in the temperature range from 235°C to 305°C using an Ubbelohde-type tilting viscometer. The “intrinsic” viscosities, η0, were estimated by extrapolating the values of the viscosities, ηθ, of various rates of shear to a zero rate of shear. The “intrinsic” viscosities of the liquid selenium were estimated to be 20.18, 13.46, 9.11, 6.32, 3.67 and 2.30 poise at 235, 245, 255, 265, 285, and 305°C respectively. The viscosities of the chlorinated liquid selenium decreased with an increase in the chlorine content, but they varied discontinuously at a chlorine content of 0.0125% and then decreased linearly. The apparent activation energy for the viscous flow of the liquid selenium was estimated to be 17.9 kcal/mol. The apparent activation energies for the viscous flow of the chlorinated selenium varied discontinuously at a chlorine content of about 0.0125%, as in the case of the viscosity. The average-chain length of the selenium molecules was considered not to be changed, but the radicals at both ends of the linear chain vanish in forming the bonds with chlorine atoms with an increase in the chlorination below a chlorine content of 0.0125%. Therefore, it is concluded that the presence of radicals at the molecular ends would have an influence upon the viscosity and the apparent activation energy for the viscous flow of selenium. The notable large value of the apparent activation energy of such a non-branched polymer as selenium was attributed to the large amount of energy needed to transport the segments into the holes.
Bipolar Ion-Exchange Membranes Prepared from Blends of Graft Copolymers
Authors: Kawabe Hiroshi , Yanagita Masaya
Published: July 2006

Bipolar ion-exchange membranes were prepared from graft copolymers of polyethylene (PE). Powders of styrene-grafted PE (I) and 4-vinylpyridine-grafted PE (II), or powders of ethyl acrylate-grafted PE (III) and II were blended in various proportions and melt-pressed to films. Ion-exchange groups were then introduced by the sulfonation (100%), alkaline hydrolysis (100%), or N-methylation (80–90%) of the blend polymer films. Although, in the titration curves of bipolar membranes, pH regions which apparently resemble the isoelectric point of polyampholytes appeared, no behavior based on the interaction between acidic and basic groups was indicated in the survey of their physico-chemical properties. The dependency of the concentration potential of the membranes (Em), containing one kind of ionized group, on the mole fraction of the group (Fi) is not remarkable. On the other hand, the Em of the membranes containing both positively- and negatively-charged groups is strongly dependent on Fi, because of the additive contribution of the oppositely-charged groups to the potential. The bi-ionic potential of the membrane, EK–Li, was found to be a function of Em⁄|E0|(|E0| is the absolute value of the concentration potential for ideal permselective membranes) in the cases of both I-II and II-III.
The Anodic Reaction of Acetic Acid in the Presence of Enanthaldehyde, Enanthaldehyde Diethyl Acetal, and 2-Octanone
Authors: Takeda Akira , Wada Satosi , Torii Sigeru , Matsui Yuji
Published: July 2006

The anodic methylation of enanthaldehyde, enanthaldehyde diethyl acetal, and 2-octanone was attempted by electrolyzing a mixture of acetic acid, ethanol (or tetrahydrofuran and/or acetone), water, and potassium hydroxide. The major products from the electrolysis of enanthaldehyde consisted of 2-octanone, 1-heptanol, 3-methyl-2-octanone, and enanthaldehyde diethyl acetal. Similar products were isolated from the reaction mixture of enanthaldehyde diethyl acetal. The anodic methylation of 2-octanone gave 3-methyl-2-octanone as a major product. Possible mechanisms of the formation of these ketones were discussed.
The Rotatory Dispersion and Stereochemistry of Organic Compounds. XV. Nitrophenyl Glycosides
Authors: Tsuzuki Yojiro , Koyama Motoo , Aoki Kazuyuki , Kato Tatsuo , Tanabe Koko
Published: July 2006

It has been reported that some ortho-nitrophenyl glycosides exhibit anomalous optical rotation (Montgomery et al., J. Am. Chem. Soc., 64, 690 (1942)). To investigate this anomalous effect of the ortho-nitro group the authors have observed the RD spectra on twenty-five derivatives of o-nitrophenyl, p-nitrophenyl and phenyl glycosides. Every o-nitrophenyl derivative (I, IV, VII, XI, XIV, XVII and XX) exhibited a positive Cotton effect near 340 mμ. Furthermore, in order to inquire into this anomaly the authors have observed the CD and UV spectra of these compounds. It follows that the o-nitro group is twisted from the benzene ring plane, and that the o-nitrophenyl group itself becomes an optical active chromophore, so that the Cotton effects near 340 mμ are caused by the n→π* transition of the nitro group. Therefore, the anomaly of o-nitrophenyl glycosides in the [α]D values is concluded to be affected by the strong Cotton effect near 340 mμ.
The Synthesis of Methylacetylene by the Pyrolysis of Propylene. IV. The Pyrolysis of Allyl Chloride
Authors: Kunichika Sango , Sakakibara Yasumasa , Taniuchi Mamoru
Published: July 2006

Allyl chloride has been pyrolyzed in a flow system over a wide range of conditions (temperature, 800–1200°C; contact time, 0.665×10−3–78.9×10−3 sec; concentration, 4.0–13.5 mol%; pressure, atmospheric pressure) to find suitable conditions for producing methylacetylene and allene. In addition, a study on the mechanism of pyrolysis of allyl chloride at high temperatures (800–1200°C) has been made. A total yield of allene and methylacetylene of 14 mol per 100 mol of allyl chloride pyrolyzed was obtained under suitable conditions. By means of the zero conversion method, hydrogen, propylene, allene, diallyl, 1,3-cyclohexadiene, and benzene have been found to be the main reaction products in the early stage of the pyrolysis, while methane, acetylene, ethylene, methylacetylene, butene-1, and butadiene have been found to be the side reaction products. The over-all activation energy of decomposition was 39.4 kcal/mol for an A factor of 108.7 sec−1. On the basis of the observed results, a free-radical mechanism has been proposed for the main reactions and the principal side reactions. It was further concluded that the pyrolysis was a radical decomposition initiated by the reaction C3H5Cl→C3H5·+Cl and that the over-all mechanism in the early stage of the pyrolysis was represented essentially by the reaction 2C3H5Cl→C3H5·+\dotC3H4Cl+HCl.
Alkoxysilanes. II. Preparation of Tributoxysiloxychlorosilanes, Silanols, and Their Polymeric Substances
Authors: Abe Yoshimoto , Kijima Ichiro
Published: July 2006

Tributoxysiloxychlorosilanes [(BuO)3SiO]xSiCl4−x(Bu=t: x=1,2; Bu=s: x=1,2,3 or 4) were prepared by the reaction of silicon tetrachloride with tributoxysilanol in the presence of pyridine. The hydrolysis of these compounds led to the formation of tributoxysiloxysilanols [(BuO)3SiO]xSi(OH)4−x (Bu=t: x=2; Bu=s: x=2 or 3). Tri-t-butoxysiloxysilanetriol was obtained from the corresponding trichlorosilane under mild hydrolytic conditions by using aniline as an hydrogen-chloride acceptor. On the other hand, the hydrolysis of the trichlorosilane with excess water in the presence of pyridine gave a resinous product. The fractional precipitation of this product gave a white powder soluble in such organic solvents as benzene, n-hexane, ether, and carbon tetrachloride; the powder had a molecular weight between 2500 and 4300. This resin turned into glassy solids upon being heated at 200 or 300°C under reduced pressure; these solids had molecular weights between 5500 and 12500. The possible structures for these polymeric substances were discussed on the basis of the results of the elemental analysis, the IR spectra, and the gas chromatography of volatile substances produced in the course of polymerization.
Synthesis of Carboxylic Acid from Aryl Halide and Carbon Monoxide Catalyzed by Nickel Carbonyl
Authors: Nakayama Mikitake , Mizoroki Tsutomu
Published: July 2006

In the reacion of aryl bromide with carbon monoxide in the presence of water and a catalytic amount of nickel carbonyl, it has been found that aromatic carboxylic acids (benzoic acid, polymethylbenzoic acid, α-naphthoic acid, etc.) are formed in very high yields when such salts of carboxylic acids as potassium acetate or sodium benzoate are added to the starting materials. The carbonylation reaction of aryl bromide is strongly inhibited by the hydrobromic acid formed, and the addition of the salt of carboxylic acid effectively decreases its concentration in the course of the reaction. When the amount of potassium acetate is larger than that of aryl bromide, the rate of the carbonylation reaction of bromobenzene to form benzoic acid is proportional to the amounts of bromo-benzene, nickel tetracarbonyl, and water and to the reciprocal of the carbon monoxide pressure. From these kinetic data, the effect of the salts of carboxylic acids and the course of the reaction are discussed.
Molecular Orbital Treatment of Nitric Oxide Radicals. II. ESR Spectra of Aliphatic Nitric Oxide Radicals
Authors: Kikuchi Osamu
Published: July 2006

Quantitative discussions of the ESR spectra of aliphatic nitric oxide radicals have been undertaken on the basis of the molecular orbitals of all-valence-electrons, which were evaluated by the approximate SCF method with the CNDO/2 approximation. The spin density on the methyl proton in the dimethyl nitric oxide radical is proportional to cos2θ, where θ is the angle between the nitrogen 2pz orbital and the plane containing the C–N and the G–H bonds; the small hyperfine splitting constants of β-protons appearing in some substituted nitric oxide radicals are understood as resulting from the sterically-restricted conformations of substituted groups. The deviation of the g factor of aliphatic nitric oxide from the free spin comes from the large spin densities localized on the nitrogen and the oxygen atoms, and the small excitation energy, from the nonbonding orbital of the oxygen to the odd π-orbital. The electronic structures and g factors of some other radicals are compared to those of aliphatic nitric oxide radicals.
Determination of the S*–T Transition Probabilities of Some Xanthene and Thiazine Dyes on the Basis of the T-Energy Transfer. I. Experiment in Ethanol Solutions
Authors: Nemoto Masae , Kokubun Hiroshi , Koizumi Masao
Published: July 2006

Intersystem crossing probability, \varphiSTA for fluorescein, eosine, erythrosine, methylene blue and thionine in ethanol (only for fluorescein, 30 vol% alkaline aqueous ethanol solution), has been determined by comparing the quantum yield of the direct (Φ) and sensitized photoreduction (Φs), on the basis of the following relations,

Φ=\varphiSTAβ Φs=\varphiSTDγβ

where β is the fraction of triplet dye molecules that are reduced eventually, \varphiSTA and \varphiSTD are respectively for acceptor (dye) and donor (sensitizer) and γ is the energy transfer efficiency, which was assumed as 1. ATU was used as a reducing agent. 1,2,5,6-dibenzanthracene, triphenylene, anthracene and β-acetonaphthone were used as sensitizers. It has been confirmed that the above relations and assumption hold generally. Different sensitizers usually gave nearly the same \varphiSTA values (with the exception of thionine-anthracene. β-Acetonaphthone gave in general somewhat smaller values). The most probable \varphiSTA values obtained are; fluorescein (0.007), eosine 0.43±0.04, erythrosine 1.1±0.06, methylene blue 0.52±0.03, thionine 0.62±0.03. The values for xanthene dyes agree moderately well with the ones reported by Porter et al. for the aqueous solution of pH=9, fluorescein 0.05, eosine 0.71, erythrosine 1.07. Using the above \varphiSTA values, the ratio of the deactivation and genuine reaction between triplet dye and ATU has been evaluated. The ratio increases in the order, fluorescein<eosine<erythrosine, thionine<methylene blue.
Photooxidation of Anthracene
Authors: Sugiyama Noboru , Iwata Masaaki , Yoshioka Michikazu , Yamada Kazutoshi , Aoyama Hiromu
Published: July 2006

It was found that anthracene (I) was converted to 9,10-anthraquinone (III) and bianthrone (IV) by irradiation via anthracene peroxide (II). The reaction proceeded most effectively in carbon disulfide. Also IV was found to be oxidized to III by oxygen in singlet state.
Oligomerization of Isoprene by Hafnium Catalysts
Authors: Misono Akira , Uchida Yasuzo , Furuhata Ken-ichi , Yoshida Shohei
Published: July 2006

Oligomerization of isoprene by the catalyst system consisting of hafnium(IV) n-butoxide and diethylaluminum chloride was studied. Isoprene was oligomerized to a mixture of dimers, trimers and higher oligomers. The compound, 2,6-dimethyl-1-trans-3,6-octatriene, was the main dimer of isoprene in this reaction. The maximum yield of this dimer in the reaction at 130°C for 2 hr was accomplished when the molar ratio of diethylaluminum chloride to hafnium(IV) n-butoxide was 4.7. The addition of tetrahydrofuran or triphenylphosphine kept the selectivity for the dimer nearly constant. These results were compared with those obtained by the catalyst system consisting of titanium (IV) n-butoxide or zirconium(IV) n-butoxide and diethylaluminum chloride.
Specific Association of Riboflavin and Adenine Derivatives in Chloroform Solution and the Effect of Barbiturates on the Association
Authors: Kyogoku Yoshimasa , Yu Byung Sul
Published: July 2006

Riboflavin-2′,3′,4′,5′-tetraacetate and tetrabutyrate have been found to associate with 9-ethyladenine. They form stronger complexes with each other than with themselves and with other nucleic acid purine and pyrimidine derivatives. The association constants of the formation of the complexes were determined from the infrared spectra to be 130 and 95m−1 respectively. The complex is a 1 : 1 cyclic hydrogen bonded dimer through the imino and the 2-C carbonyl groups of the isoalloxazine ring and the amino group of the adenine residue. 9-Ethyladenine is an effective quencher of the fluorescence of riboflavin tetraacetate. The quenching appears mainly due to the coplanar interaction through hydrogen bonds and partly due to the collision interaction with the purine rings. Some barbiturates were found to prevent the formation of the complex of the adenine and riboflavin derivatives by the formation of more stable complexes with ethyladenine.
Synthetic Studies of the Flavone Derivatives. X. The Synthesis of 3,4′,5-Trihydroxy-3′,6,7-trimethoxyflavone and the Structures of Chrysosplenin and Chrysosplenetin
Authors: Fukui Kenji , Matsumoto Takashi , Tanaka Sachihiko
Published: July 2006

The acid-catalyzed isomerization of 4-benzyloxy-2′-hydroxy-3,4′,5′,6′-tetramethoxychalcone gave 4′-benzyloxy-3′,5,6,7-tetramethoxyflavanone, which was then converted by oxidation to 4′-benzyloxy-3-hydroxy-3′,5,6,7-tetramethoxyflavone. This, after debenzylation to 3,4′-dihydroxy-3′,5,6,7-tetramethoxyflavone, was partially demethylated with aluminum chloride or aniline hydrochloride to give 3,4′,5-trihydroxy-3′,6,7-trimethoxyflavone (I) (mp 213–214°C), the structure proposed previously for the chrysosplenetin (mp 177–178°C) isolated from Chrysosplenium japonicum Makino. However, the synthetic flavone was found to be different from natural chrysosplenetin by a mixed melting point determination and by a comparison of the spectra. Finally, the structures of chrysosplenetin and chrysosplenin were established by the spectroscopic studies to be 4′,5-dihydroxy-3,3′,6,7-tetramethoxyflavone (XIII) and its 4′-glucoside (XIV) respectively. The revised structure for chrysosplenetin has been fully confirmed by direct comparison with an authentic sample.
Polarographic Studies of Dissolved Oxygen in DMSO-Water Mixtures
Authors: Fujinaga Taitiro , Izutsu Kosuke , Adachi Takeo
Published: July 2006

The solubility and polarographic behavior of dissolved oxygen have been investigated in air-saturated DMSO-water mixtures at 25°C and 45°C. The first oxygen wave, which corresponds to one-electron reduction to superoxide ions in water-poor DMSO solutions of 0.1 m Et4NClO4, changes to a two-electron process in the range of water content between 10 and 30% because of the protonation reaction due to water. The rate of protonation is potential-dependent. The rate also depends on the species and the concentrations of the supporting electrolytes. The temperature effect is small. Using the solubility and polarographic data obtained, the polarographic diffusion coefficients of oxygen in the mixed solvent have been calculated.
Spectroscopic Studies of Poly nuclear Complexes. I. Preparations and Circular Dichroisms of Tetrakis(l-propylenediamine)-dicobalt(III) Complexes Containing μ-Amido Group
Authors: Sasaki Yoichi , Fujita Junnosuke , Saito Kazuo
Published: July 2006

New binuclear cobalt(III) complexes, (−)D-[(l-pn)2Co(μ-NH2,O2)Co(l-pn)2](NO3)4·3H2O, (+)D-[(l-pn)2Co(μ-NH2,O2)Co(l-pn)2]I3·6H2O, (+)D-[(l-pn)2Co(μ-NH2,NO2)Co(l-pn)2]Br4·6H2O, (+)D-[(l-pn)2Co(μ-NH2,OH)Co(l.pn)2](NO3)4·2H2O and (−)D-[(l-pn)2Co(μ-NH2,SO4)Co-(l-pn)2](NO3)3 were prepared and their absolute configurations determined to be ΛΛ on the consideration of the stereospecific coordination of l-propylenediamine (l-pn) to the metal ion. On the basis of these identifications, absolute configurations of the corresponding ethylenediamine-(en) complex ions were assigned. The nature of the d–d bands of these polynuclear complexes seems to be very similar to those of uninuclear cobalt(III) complexes. One of the two central cobalt(III) ions is regarded as a member of an asymmetric chelate ligand to the other cobalt ion, and the CD corresponding to the d–d bands appears to depend mainly on the strength of vicinal effect due to such a chelate ring.
Polarographic Studies of the Solubilization of Disperse-dyes
Authors: Hayano Shigeo , Shinozuka Noriko
Published: July 2006

The apparent mean particle size of the solubilized dye in nonionic surfactant solutions is determined from the polarographic diffusion coefficient. The diffusion coefficient and the particle size obtained are in good agreement with those of the nonionic surfactant micelle reported in the literature. For the system of polyoxyethylene nonylphenyl ether (NP-\bar19) and 1,4-diaminoanthraquinone, the particle size increases with the dye concentration; however, the particle size is almost constant for the system of NP-\bar19 and 1,4,5,8-tetraaminoanthraquinone (TAA). When a certain quantity of TAA is solubilized into the 10−3–10−2m NP-\bar19 solution, the particle size is also constant. In the case of the polyoxyethylene lauryl ether (LA-\bar14) and TAA system, the particle size markedly decreases with the increase in the dye concentration. This tendency suggests that the numbers of micelles increase with the concentration of the solubilizate. The fact that the half-wave potential of the dye reduction is independent of the concentration of the surfactants is explained in terms of the similarity between the electrode process of the solubilized dye and that of the dissolved dye.
Nature of Acid Sites on the Surface of Silica-alumina. I. The Relation between the Acid Property of Sites and the Heat of Immersion
Authors: Miura Masaji , Kubota Yukio , Iwaki Toru , Takimoto Kazuto , Muraoka Yoshinori
Published: July 2006

The acidity and the acid strength of the sites of such solid catalysts as silica gel, alumina, and silica-alumina were determined by the n-butylamine titration method using the Hammett indicators. The distribution of the acid sites on the surfaces of these catalysts was found to vary with the outgassing temperature, and also with the alumina content in the case of silica-alumina. The heats of immersion of these catalysts in water and in an aqueous solution of n-butylamine were measured. The heat value corresponding to the difference between these two cases, as well as the number of acid sites, showed a maximum at contents of 10–20%. These phenomena are discussed with reference to the results of the diffuse reflection measurements.
The Crystal Structure of Riboflavin Hydrobromide Monohydrate
Authors: Tanaka Nobuo , Ashida Tamaichi , Sasada Yoshio , Kakudo Masao
Published: July 2006

The crystal structure of riboflavin hydrobromide monohydrate has been determined by a three-dimensional X-ray analysis. The space group is P 212121 with four formula units in the unit cell of dimensions a=18.28, b=6.99 and c=14.77 Å. The structural parameters were refined by means of a block-diagonal least-squares method, the final R factor being 0.07. The ribitol does not form a furanose ring but a chain. The protonation of the isoalloxazine ring occurs at the N(1) atom, and the C(4a)-N(10) bond is found to be a double bond. The bromide ion is situated midway between two isoalloxazine rings separated by a period along the b axis.
Preparation and Circular Dichroism of trans(N)- and cis(N)-Isomers of (Ammoniatriacetato)(amino-acidato)cobalt(III) Complexes
Authors: Koine Norio , Sakota Naokazu , Hidaka Jinsai , Shimura Yoichi
Published: July 2006

Eleven new complexes, trans(N)- or cis(N)-isomers of (ammoniatriacetato)(amino-acidato)cobalt(III) ions, have been synthesized as their potassium salts, where the amino acids are glycine, β-alanine, γ-aminobutyric acid, sarcosine, l-alanine, l-serine, l-valine and l-proline. The geometrical isomers have been separated by ion-exchange column chromatography and their structures determined on the basis of their absorption spectra and proton magnetic resonance spectra. Stereoselectivity about the formation of the trans and cis isomers was found. The circular dichroism of the complexes containing optically active amino acidato ligands has been measured and discussed in relation to so-called vicinal contribution by the optically active ligands.
Studies on Fluorene Derivatives. XXV. Abnormal Products, Tribiphenylenepropanes, of the Michael Addition of 9,9′-Bifluorenylidenes and Fluorenes, and Syntheses of Related Compounds
Authors: Suzuki Kazuo , Minabe Masahiro , Fujimoto Minoru , Nohara Noboru
Published: July 2006

A normal compound, 2′,7′-dibromotribiphenylenepropane (IV), and an abnormal compound, 2′,7′,2″,7″-tetrabromotribiphenylenepropane (VI), were obtained by the Michael addition of 9,9′-bifluorenylidene (I) and 2,7-dibromofluorene (III). In addition, another normal compound, 2,7,2′,7′-tetrabromotribiphenylenepropane (VIII) and three abnormal compound, IV, VI, and tribiphenylenepropane (VII), were isolated by the Michael addition of 2,7,2′,7′-tetrabromo-9,9′-bifluorenylidene (IX) and fluorene (II). In both cases, the normal compounds were obtained in the presence of sodium ethoxide in ethanol. The abnormal compounds might be formed by the further condensation of 2,7-dibromo-9,9′-bifluorenylidene (V) and III or II in the presence of alkali. The related compounds, 2,7-dibromotribiphenylenepropane (X), IV, VI, VIII, and 2,7,2′,7′,2″,7″-hexabromotribiphenylenepropane, were synthesized by the reaction of substituted 9-fluorenyllithium and substituted 9-bromo-9,9′-bifluorenyl in an absolute xylene solution. The thermal decomposition of X and VIII afforded bromosubstituted or nonbromosubstituted-9,9′-bifluorenylidenes, 9,9′-bifluorenyls, fluorenones, and fluorenes. The ethanolysis of 2,7-dibromo-9′-hydroxy-9,9′-bifluorenyl gave fluorenone and III.
Kinetics of Multidentate Ligand Substitution Reactions. IV. Substitution Reactions of BT with Cobalt(II) and Nickel(II) Chelates of 1,2-Diaminocyclohexanetetraacetic Acid and Diethylenetriaminepentaacetic Acid
Authors: Kodama Mutsuo , Sasaki Chifumi , Miyamoto Katsumi
Published: July 2006

The substitution reactions of Eriochrom Black T (BT) with cobalt(II) and nickel(II) chelates of 1,2-diaminocyclohexanetetraacetic acid (CyDTA) and of diethylenetriaminepentaacetic acid (DTPA) were studied spectrophotometrically. The reactions of BT with CyDTA and DTPA chelates of these metal(II) ions were found to have the same reaction mechanism as the reactions with EDTA chelates did, but to be considerably slower than the latter reactions. On the basis of a comparison of the observed rate constants with those calculated on the basis of the proposed reaction mechanism (glycinate intermediate), the steric effect due to the cyclohexane ring in the CyDTA or –CH2–CH2–N(CH2–COO−)–CH2–CH2–N(CH2–COO−)2 group in DTPA on the reaction rate was discussed in a quantitative manner. The effect due to the former group was estimated to be smaller than that due to the latter group.
The Hydrogenation Catalysts Prepared from Transition Metal Chloride and Triethylaluminum
Authors: Takegami Yoshinobu , Ueno Toru , Fujii Takao
Published: July 2006

Catalysts composed of anhydrous iron(III) chloride, cobalt(II) chloride, or nickel(II) chloride plus triethylaluminum have been used for the hydrogenation of olefin. The catalytic activity has changed with the Al(C2H5)3/MCln ratio. The optimum ratios for the hydrogenation of styrene have been found to be 1–7 for the iron catalyst, 0.2–1 for the cobalt catalyst, and 0.3–2 for the nickel catalyst. Cyclohexane has been used satisfactorily as a solvent. Tetrahydrofuran could be used for the nickel catalyst, but its presence was unfavorable for the iron and cobalt catalysts. The gas evolved in the reaction of the transition metal chlorides with triethylaluminum has been found to be essentially ethane, and sluggish gas absorption was observed when the atmosphere was switched to hydrogen. Ethylbenzene was formed in the treatment of the catalyst with styrene under nitrogen; the amount increased considerably if the catalyst was pre-treated with hydrogen. Ethane was formed in the hydrogen-treatment of the reaction mixture of nickel chloride and triethylaluminum. On the basis of these results, it has been assumed that metal hydride has been formed by the hydrogenolysis of metal - ethyl bonds.
Mass Spectrometry of Tautomeric Compounds. I. Absence of Keto-Enol Tautomerism in Fragment Ions
Authors: Nakata Hisao , Tatematsu Akira
Published: July 2006

In order to examine a possibility of keto-enol tautomerism in molecular and fragment ions, diethyl di-n-butylmalonate (Ia), methyl 2-n-butylhexanoate (IIa), and 2,2-di-n-propyl-5,5-dimethyl-1,3-cyclohexanedione (IIIa) were synthesized and their mass spectra were compared with those of respective mono-alkyl derivatives, Ib, IIb, and IIIb. The first step of the fragmentation of each dialkyl compounds is the cleavage of one of the alkyl side chains by McLafferty rearrangement to give an enol fragment ion (E). Comparisons of the behavior of this enol fragment ion with that of the corresponding molecular ion (K) of mono-alkyl derivatives indicate that the keto and enol forms of these compounds exhibited entirely different fragmentation patterns. Thus, the enol fragment ion of m/e 216 from Ia loses C3H7· through the allylic cleavage of an enol double bond to give an abundant m/e 173 peak, while the keto ion of m/e 216 from Ib loses C4H8 to afford a strong m/e 160 peak. In a similar manner, the enol fragment ion of m/e 130 from IIa gives an intense peak at m/e 87, and the keto ion of m/e 130 from IIb yields an ion at m/e 74. In the spectrum of IIIa, a peak at m/e 140 that is observed in the IIIb spectrum did not appear. These results clearly suggest that no keto-enol tautomerism takes place in these ions in a mass spectrometer.
Metal Complexes with Amino Acid Amides. II. Preparations and Circular Dichroism Behavior of the Copper(II) Complexes
Authors: Komorita Takashi , Hidaka Jinsai , Shimura Yoichi
Published: July 2006

Planar bis-type complexes of copper(II) with l-leucine-, l-valine-, l-phenylalanine- and l-proline-amidate ligands have been newly synthesized and characterized mainly spectroscopically together with the known complexes with glycine- and l-alanine-amidates. The geometrical structures of these [Cu(N)4]-type complexes have been tentatively determined. The blue colored complexes, Cu(glycine-amide)2SO4 and its l-alanine amide analogue, have been isolated, too. The circular dichroism spectra of the complexes containing optically active ligands have been measured in various solvents and discussed in comparison with the available data for square planar d8-complexes or for amino acidato complexes. A number of interesting relations were observed among the circular dichroism spectra of the copper(II) and the square planar d8 complexes with optically active bidentate ligands.
Reaction Rates in Binary Mixed Solvents.
Authors: Kondo Yasuhiko , Kusaka Toshiharu , Tokura Niichiro
Published: July 2006

The rate constants of the Menschutkin reaction between methyl iodide and pyridine, N,N-dimethylaniline, 2,6-dimethylpyridine, and N,N-dimethyl-o-toluidine have been measured in a liq. SO2-nitrobenzene mixture. These results have then been analyzed by the procedure described in a previous paper. The findings regarding the reactions of unsubstituted amines with methyl iodide have been explained theoretically by taking into account the specific solvation of amines by liq. SO2 and that of an activated complex by a nitrobenzene solvent, whereas the behavior of the rate constants in the reactions of o-substituted amines in mixed solvents can be explained by assuming the specific solvation of an activated complex by liq. SO2 only. In conformity with the above results and the difference in the effect of an o-methyl group on the reaction rates between liq. SO2 and a nitrobenzene solvent, the mutual relation of the activation free energies of these reactions has been discussed.
Photoreversible Photographic Systems. VI. Reverse Photochromism of 1,3,3-Trimethylspiro[indoline-2,2′-benzopyran]-8′-carboxylic Acid
Authors: Shimizu Isamu , Kokado Hiroshi , Inoue Eiichi
Published: July 2006

Many derivatives of 1,3,3-trimethylspiro[indoline-2,2′-benzopyran] (1) exhibit photoreversible color changes in organic solvents. One of the derivatives 1,3,3-trimethylspiro[indoline-2,2′-benzopyran]-8′-carboxylic acid (2) shows “reverse photochromism” in polar solvents. The compound 2 exhibits a deep color in the polar solvent and the color is bleached by irradiation with either visible or ultraviolet light. The color reappears thermally as the irradiation is ceased. The thermal conversion rate from the colorless form to the colored one depends on the solvents. On the other hand, the isomer 1,3,3-trimethylspiro[indoline-2,2′-benzopyran]-6′-carboxylic acid shows neither normal nor reverse photochromism under usual conditions, but exhibits reverse photochromism when acid such as malonic acid is added into the solution. The compound 2 is assumed to have a merocyanine dye-like structure due to the intramolecular proton transfer.
Solvent Effects of Charge-transfer Complexes
Authors: Aihara Jun-ichi , Tsuda Motoyuki , Inokuchi Hiroo
Published: July 2006

The solvent effects of charge-transfer complexes were examined in various solvents. During the course of investigations pertaining to aromatic-TCNE complexes, Brownstein’s and McRae’s formulae were found to be valid. The gas-phase spectra of these charge-transfer complexes may be regarded as the origin of the solvent effects. The anomalous behaviour of carbonyl solvent molecules was also discussed.
Derivatographic Studies on Transition Metal Complexes. I. Deaquation-Anation Reaction of Aquopentaamminechromium(III) Complexes
Authors: Tsuchiya Ryokichi , Kaji Yoriko , Uehara Akira , Kyuno Eishin
Published: July 2006

By using a Derivatograph, the simultaneous analyses in TGA, DTA and DTG on the several aquopentaamminechromium(III) complexes were attempted. The enthalpy changes, ΔH, in the deaquation-anation processes of aquopentaamminechromium(III) nitrate, chloride, bromide, iodide, sulfate and sulfite were calculated as 11.9, 6.1, 9.0, 10.8, 13.8 and 12.8 kcal/mol, respectively, the activation energies, E\eweq, in the corresponding processes of the nitrate, chloride, bromide, sulfate and sulfite were obtained by the DTG curve analysis as 18, 28, 38, 36 and 33 kcal/mol, and those in the nitrate, chloride, bromide, iodide, sulfate and sulfite were obtained by the DTA curve analysis as 14, 25, 36, 19, 39 and 32 kcal/mol, respectively.
Studies on Stable Free Radicals. III. Reactions of Stable Nitroxide Radicals with S-Radicals Derived from Benzenethiols and Thiamine
Authors: Murayama Keisuke , Yoshioka Takao
Published: July 2006

The reaction of the extremely stable free radical, 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (I), was carried out with benzenethiols (IV). The formation of diphenyl disulfides (VI), benzenesulfinic acids (VII), and 1-(p-substituted benzenesulfinyl)-2,2,6,6-tetramethyl-4-oxopiperidines (X) from the above reaction shows that the radical (I) can act as a hydrogen-abstracting agent, an oxidizing agent, and a radical scavenger. Possible mechanisms for the coupling reaction of the radical (I) with the S-radicals (V) to give the sulfinamides (X) were discussed. A substituent effect was observed in the formation of the disulfides (VI). The N-oxyl radical (I) and another stable free radical, such as 2,6-di-t-butyl-4-methylphenoxyl radical (XXV), were shown to react with the S-radical (XVII) derived from thiamine (XIV) to give new types of thiamine derivatives, S-(2,2,6,6-tetramethyl-4-oxopiperidino) thiamine (XX) and S-(2,6-di-t-butyl-4-methylphenoxy)thiamine (XXVI) respectively.
Reaction of Xanthates with t-Amines. VI. The Reaction Mechanism
Authors: Yoshida Hiroshi
Published: July 2006

It was previously reported that xanthate reacted with t-amine to give quaternary ammonium salt at room temperature, and dithiolcarbonates at elevated temperatures. Precise study showed that these reaction products are formed by the following three reactions: the alkylation of t-amine with xanthate affords quaternary ammonium salt and the reaction of xanthate with quaternary ammonium salt yields dithiolcarbonate, while there is transesterification between thiolesters and quaternary ammonium salt. The rate constants and equilibrium constants of these reactions were calculated.
The Mechanism of the Alkaline Decomposition of Triarylsulfonium Bromide with Phenyllithium
Authors: Khim Yong He , Oae Shigeru
Published: July 2006

Tritolylsulfonium bromide was subjected to alkaline decomposition in order to clarify the mechanism of the reaction of triarylsulfonium bromide with phenyllithium in ether. Diaryl sulfides, diaryls, and other aryl derivatives were obtained and the combined yield was nearly quantitative. On the basis of the ratio of the products formed in the reaction, the alkaline decomposition is considered to proceed through two mechanistic routes, i. e., one involving the nucleophilic attack of phenyl anion on the sulfur atom (about 70%) and the other the “benzyne” route (about 20%).
Diffusion Coefficients of Xylose and Maltose in Aqueous Solution
Authors: Ueadaira Hisashi , Uedaira Hatsuho
Published: July 2006

Diffusion coefficients for the systems aqueous xylose solution and aqueous malotse solution at 25°C were measured by the Rayleigh interference method. Viscosities of these systems were also determined. The concentration dependence of diffusion coefficient for maltose solution is well described by the Gordon relation. For xylose solution, however, a small deviation from this relation is observed. The translational frictional coefficient of maltose was calculated by the shell model of Bloomfield et  al. If the effect of the local viscosity around a molecule of the solute is corrected, the agreement between the calculated and the observed values is satifsactory.
ESR and Optical Absorption Studies of the Copper(II) Complexes of Ethylenediamine and Its Alkyl Derivatives
Authors: Yokoi Hiroshi , Isobe Taro
Published: July 2006

The ESR and the optical absorption of the copper(II) complexes of ethylenediamine and a series of alkylated ethylenediamines have been investigated in order to estimate the character of the chemical bonding in the copper(II) complex. The covalency of the bonding of the copper atom to the ligand nitrogen atoms in the complexes has been discussed in connection with the chemical and physical properties of the complexes or of their ligand molecules themselves. The ESR results indicate that the σ bonding of the complexes becomes more covalent as the number of alkyl groups in their ligand molecules increases; furthermore, the tendency toward the σ bonding becomes more pronounced when the alkyl groups are ethyl rather than methyl and when they are N-substituted alkyl groups rather than C-substituted ones. It is also indicated that there is a linear relationship between the energies of the ultraviolet absorption band for the complexes and the relative ionization potentials estimated for their ligand molecules, and that absorption band can be assigned to an electron transfer from a ligand σ orbital to an antibonding orbital associated with the copper atom. From these results, it may be concluded that, as the σ bonding becomes more covalent, this charge transfer band shifts to a longer wavelength.
Deprotonation of Oxime Complexes: Dimethylglyoxime-Cobalt(III) Complexes
Authors: Masuda Isao , Sakano Mitsuhiro , Shinra Koichiro
Published: July 2006

Dimethylglyoxime-Co(III) complexes with the formula [Co(dmgH)2A2]n (I), where dmgH is dimethylglyoximato mono-anion, A is an axial ligand such as aniline, p-anisidine, pyridine, γ-picoline, imidazole, NH3, CN−, and NO2−, and n is −1, 0, or +1, were found to change their electronic absorption spectra reversibly depending on the pH of the solution. These changes have been attributed to the dissociation of the proton from the intramolecular hydrogen bridges of the complex; the changes are accompanied by the formation of the complex [Co(dmgH)(dmg)A2]n−1, where dmg represents the dimethylglyoximato di-anion. The proton dissociation constants (pKa) obtained by the spectrophotometric method indicated that the complex I is generally a weak acid of pKa=7.7–12.6. With the exception of the pyridine and the γ-picoline ligand, axial ligands do not appreciably affect the pKa values. However, axial pyridine and the γ-picoline ligand increase the tendency of the hydrogen bridges to dissociate the proton.