bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Chromium(III) Complexes with Natural α-Amino Acids
Authors: Mizuochi Hisayuki , Uehara Akira , Kyuno Eishin , Tsughiya Ryokichi 
Published: July 2006

Abstract
The following chromium(III) complexes with natural α-amino acids were prepared: [Cr(α-ambut)3]·2H2O (red) (I), (−)546-[Cr(l-leu)3]·2H2O (red) (II), (+)546-[Cr(l-leu)3]·2H2O (red) (III), [Cr(l-glu)3]·2H2O (red) (IV), (+)546-[Cr(l-lys)2(H2O)2]Cl·3H2O (red) (V), [Cr(OH)(α-ambut)2(H2O)]·H2O (light purple) (VI), [Cr(OH)(l-val)2(H2O)]·H2O (light purple) (VII), [Cr(OH)(l-leu)2(H2O)]·H2O (light purple) (VIII) and [Cr(OH)(l-glu)2(H2O)]·H2O (light purple) (IX), where α-ambut, l-leu, l-glu, l-lys, and l-val are the basic forms of α-aminon-butyric acid, l-leucine, l-glutamine, l-lysine and l-valine, respectively. From the results of electronic and infrared absorption spectra, molar conductivities and behaviors toward ion exchangers, the composition and structures of the complexes were determined. The striking information obtained is that the complexes (I)–(IV) are considered to have all the β-form unlike the corresponding cobalt(III) complexes having both α- and β-forms. On the basis of ORD and CD measurements, the complexes (II), (III), and (V) were found to be optically active.
Studies of Peptide Antibiotics. XXIV. Synthesis of 4,4′-d-Alanine-gramicidin S
Authors: Lee Sannamu , Ohkawa Reiko , Izumiya Nobuo 
Published: July 2006

Abstract
In order to investigate the contribution to antibacterial activity of the d-phenylalanine residues at 4- and 4′-position in gramicidin S, 4,4′-d-alanine-gramicidin S (XX) and 4-d-alanine-semigramicidin S (XXI) were prepared and tested for antibacterial properties. XX exhibited recognizable activity though weaker than that of gramicidin S, whereas XXI showed no activity on any of the microorganisms tested.
The Reactions of α-Substituted Carbonyl-stabilized Sulfonium Ylides with Succinic Anhydride
Authors: Mukaiyama Teruaki , Hagio Katsuaki , Takei Hisashi , Saigo Kazuhiko 
Published: July 2006

Abstract
It was found that various kinds of α-substituted carbonyl-stabilized sulfonium ylides were conveniently prepared from the corresponding sulfonium salts by treating with 50% aqueous sodium hydroxide. The reactions of sulfonium ylides with succinic anhydride afforded furofuran derivative by one step procedure in yields ranging these from 5 to 14%. The structures of furofuran derivatives were confirmed by IR spectrum, NMR sepctrum, degradation, and its behavior toward alkali and acid.
Substituents Effects on the Azo-Hydrazone Tautomerism of 4-Arylazo-2,6-di-t-butylphenols
Authors: Manda Eiichiro 
Published: July 2006

Abstract
The substituents effects on the azo-hydrazone tautomerism of 4-arylazo-2,6-di-t-butylphenols in carbon tetrachloride were studied by means of infrared and visible spectra. The substituents effects on their absorption spectra were discussed. The azo tautomers are predominant in the tautomeric equilibria of 3′- and 4′-substituted derivatives. Considerable participations of the hydrazone tautomers are found in the equilibria of the 2′-substituted derivatives having substituents capable of forming intramolecular hydrogen bonding with hydrazone-hydrogen atom. In the equilibria of 2′,6′-disubstituted derivatives, the positions of the equilibria move some what to the azo side from those of the corresponding 2′-substituted derivatives.
Hydrogenation and Hydrogenolysis. XIII. The Hydrogenation of Ethyl 4-Methyl-1-cyclohexenyl Ether over Platinum Metal Catalysts
Authors: Nishimura Shigeo , Katagiri Mamoru , Watanabe Tetsuo , Uramoto Masayoshi 
Published: July 2006

Abstract
The hydrogenation and hydrogenolysis of ethyl 4-methyl-1-cyclohexenyl ether (I) have been investigated with six unsupported platinum metals as catalysts at 25°C under atmospheric pressure of hydrogen. The hydrogenation of I in ethanol was accompanied by the formation of 4-methylcyclohexanone diethyl acetal (II), the extent of which depended on the nature of the catalyst metals. The ratio of the acetal formation to hydrogenation increased with respect to the catalyst metals in the sequence Os&lt;Ru&lt;Ir&lt;&lt;Rh&lt;Pd&lt;Pt. The amount of the hydrogenolysis to give methylcyclohexane increased in the order Pd≅Ru&lt;&lt;Os&lt;Rh&lt;Ir&lt;&lt;Pt at an initial stage of the hydrogenation in ethanol. This order in hydrogenolysis was explained in terms of the action of the ionized hydrogen on the catalyst surface and the olefin isomerization activity of the catalyst metals. The stereochemistry of the hydrogenation of I was also studied and the results were interpreted on the basis of the proposed mechanism. I was also hydro-genated in t-butyl alcohol and isopropyl ether as solvents and, except in a few cases, the proportion of hydrogenolysis decreased with solvent in the order ethanol&gt;t-butyl alcohol&gt;isopropyl ether. The stereoselectivity in ether formation did not differ much among the solvents except over palladium.
55Mn Nuclear Magnetic Resonance Studies of the Compounds with Manganese-Tin Bonds
Authors: Onaka Satoru , Miyamoto Takeshi , Sasaki Yukiyoshi 
Published: July 2006

Abstract
The nature of Mn–Sn bonds has been studied by 55Mn-NMR and IR spectroscopies of a series of compounds, R3−xXxSn–Mn(CO)5, where R is C6H5 or CH3 and where X is Cl or Br. Molecular orbital considerations have shown that the chemical shift of the 55Mn-NMR spectra is a measure of the σ-polarity of the L–Mn bond in L–Mn(CO)5-type complexes, and that the linewidth is mainly determined by the π-interaction between Mn and Sn. The π-interaction (back-donation from Mn to Sn) seems to be most pronounced in Br3Sn–Mn(CO)5 in the series of (CH3)3−xBrxSn–Mn(CO)5 compounds. The relationships among the chemical shift, the wave numbers of CO stretching modes, and the eqQ, are also shown.
The Catalytic Dehydrogenation, Dehydroxylation, and Dehydroxymethylation of Benzyl Alcohol. III. The Effect of Metal Chlorides as Additives
Authors: Ishige Masayoshi , Sakai Koji , Kawai Masatoshi , Hata Kazuo 
Published: July 2006

Abstract
This paper will describe the reaction of benzyl alcohol in the presence of various kinds of modified stabilized nickel catalysts, which had been prepared from the mother catalyst by treating it with solutions of appropriate metal chlorides. The catalytic activities of each modified catalyst for the formation of benzene, toluene, and benzaldehyde were compared in terms of the fH,fCH3, and fCHO values; the selectivities for the formation of benzene and toluene against that of benzaldehyde, SH and SCH3, were also evaluated. In general, the formation of toluene and benzene was greatly affected both by the kind and by the amount of metal chlorides used as additives. The reaction was promoted by the addition of a proper quantity of alkali metal chloride. In the cases of the reactions by lowlymodified catalysts, the decreasing order of the fH and fCH3 values according to the kind of metal ion adsorbed on the catalyst was as follows: Na+≥K+&gt;Co2+&gt;Ca2+&gt;Cd2+&gt;Ba2+&gt;Hg2+&gt;Cu2+. On the other hand, in the higher degrees of modification, the corresponding order of the fH and fCH3 values was altered to be as follows: K+&gt;Na+&gt;Co2+&gt;Cd2+&gt;Ba2+≥Ca2+&gt;Cu2+&gt;Hg2+. With regard to the modified nickel catalysts treated with 0.08 n solutions, it was found that the sequence of the fH and fCH3 values due to the kind of metal ion was roughly correlated with that of the atomic numbers of the corresponding metals. The results are discussed in connection with the general concept of catalytic chemistry.
The Preparation and Thermal Decomposition of Alkyl Acyl Dithiol- and Trithiocarbonates. A Convenient Method for the Synthesis of Thiolesters
Authors: Yoshida Hiroshi , Ogata Tsuyoshi , Inokawa Saburo 
Published: July 2006

Abstract
New alkyl acyl dithiol- and trithiocarbonates (1 and 2) were prepared from acid chlorides and tetramethylammonium alkyl dithiol- and trithiocarbonates (3 and 4). 1 and 2 decomposed at around 100°C to give the corresponding thiolesters in good yields. The kinetic studies of the decomposition of 1 and 2 showed that, in o-dichlorobenzene, the decomposition reaction was first order and that it proceeded via a four-membered intramolecular cyclic mechanism.
Methylation of Phenol over Metallic Oxides
Authors: Kotanigawa Takeshi , Yamamoto Mitsuyoshi , Shimokawa Katsuyoshi , Yoshida Yuji 
Published: July 2006

Abstract
Methylation took place only at ortho position of phenol under ah atmospheric pressure at 350°C when the reaction was carried out over an MO–Fe2O3 catalyst containing Cu, Mg, Ca, Ba, Zn, Mn, Co, or Ni each as M. The aromatic fraction in liquid products was only o-cresol and 2,6-xylenol and products substituted at para and meta positions could not be obtained. However, gasification of methanol took place simultaneously as a side reaction. From the relation between methylation and gasification, the catalytic activity was found to be effective in the order Cu&gt;Zn&gt;Ba&gt;Ca&gt;Co&gt;Mn&gt;Mg&gt;Ni. Deactivation of these catalysts was observed before the reaction reaches a steady state. The thermogravimetric curve of the used catalyst was measured. From thermal analysis the reduction of the catalyst seems to be a cause of deactivation in addition to deposition of carbonaceous materials onto the catalyst surface. The used catalysts were reclaimed through the process of Scheme 1.
Macro Rings. III. The Synthesis of [2.1.1.1]Paracyclophane
Authors: Kawato Toshio , Inazu Takahiko , Yoshino Tamotsu 
Published: July 2006

Abstract
Two new macrocyclic compounds, I and II, which incorporate, respectively, four or eight benzene rings and intervening methylene bridges attached to their para positions, were synthesized. The UV, IR, and NMR spectra of these paracyclophanes were compared with a corresponding open-chain compound, III.
Solid Complex Formation of Aminomalonic Acid with Glycine
Authors: Kinugasa Toshio , Nishijo Juziro , Hashizume Genzo , Imanishi Isamu 
Published: July 2006

Abstract
It was found by X-ray analysis that aminomalonic acid forms a solid complex with glycine in a molar ratio of 1 : 1 on crystallization from an aqueous solution. DTA-TGA of the solid complex at a heating rate of 1.0°C/min in air showed that the solid complex decarboxylates at higher temperature, but more slowly than aminomalonic acid and that both endothermic and following exothermic peaks which were distinctly observed in the region of decarboxylation of aminomalonic acid at temperatures 108–140°C are only slightly observed at 168–175°C. Activation energies in the thermal decomposition of aminomalonic acid and the solid complex, caluculated from themogravimetric curves, were 69.4 kcal/mol and 21.3 kcal/mol, respectively. The results indicate that aminomalonic acid is thermally more stabilized than the acid itself by forming the solid complex with glycine.
Proton Spin-Lattice Relaxation Studies of Intermolecular Interactions in Acetic Acid Solution
Authors: Sato Kazuo , Nishioka Atsuo 
Published: July 2006

Abstract
Proton spin-lattice relaxation measurements were carried out by the rapid-passage method on the hydroxyl and methyl protons of acetic acid in carbon tetrachloride, benzene-d6, and chloroform-d in order to investigate the effect of the self-association of acetic acid on the spin-lattice relaxation. It was found that there exists a maximum of the relaxation rate in carbon tetrachloride, and two maxima in benzene-d6 and chloroform-d, on dilution with a solvent. This relaxation behavior was attributed to the change in the self-association mechanism of acetic acid. We tried to keep the proton-density constant in all solution in order to avoid any ambiguity arising from the change in density by using the analogous deuterated compounds.
Syntheses of a New Series of Transition Metal Chelates of Diphenylphosphinothioylthiourea Anion
Authors: Ojima Iwao , Onishi Takaharu , Iwamoto Toschitake , Inamoto Naoki , Tamaru Kenzi 
Published: July 2006

Abstract
New thiourea derivatives, 3-diphenylphosphinothioyl-1 -phenylthiourea (PTTU-A), 3-diphenylphosphinothioyl-1,1-diethyl thiourea (PTTU-B), and 3-diphenylphosphinothioyl-1,1-dimethylthiourea (PTTU-C) were found to behave as bidentate ligands with transition metal ions such as Ni(II), Pd(II), Co(II), and Cu(II) to give a series of novel metal chelates. The structures of these complexes are discussed on the basis of magnetic susceptibilities, infrared spectra, electronic spectra, powder X-ray diffraction patterns and elemental analyses. Tentative assignments of two metal-sulfur stretching vibrations in the far infrared spectra were made for Ni-PTTU and Pd-PTTU, which have square-planar configurations. However, the structures of the Cu-PTTU complexes could not be determined by these methods because of the instability of the complexes. They were confirmed by electronic and ESR spectroscopies.
Some Displacement Reactions of Neopentyl Type Bromide Derived from Thujopsene
Authors: Ito Masaaki , Abe Kazuo , Takeshita Hitoshi , Yatagai Mitsuyoshi 
Published: July 2006

Abstract
The reaction of thujopsene with gaseous hydrogen bromide at low temperature affords a 48% yield of neopentyl type bromide. The reactivity of the homoallyl bromide was inspected. First, the neopentyl type bromide was derived to a diethyl widdryl malonate in order to demonstrate the reaction which indicates the involvement of homoallylcyclopropylcarbinyl ion system. The malonate was converted to a carboxylic acid and then to isomeric lactone. To demonstrate the reaction which suggests the retention of carbon frame work in the reaction, the reaction of the neopentyl bromide was extended to Grignard reaction. The Grignard reagent reacted with cyclohexanone gave a tertiary alcohol, whereas a dimeric hydrocarbon was also obtained through the Wurtz type condensation. The tertiary alcohol was converted to a dehydrated hydrocarbon and then a glycol.
Electronic Structure of Lone Pairs. III. H2S2, H2O2, N2H4, and Diimides
Authors: Yamabe Hiroko , Kato Hiroshi , Yonezawa Teijiro 
Published: July 2006

Abstract
The electronic structure, the electronic transition, and the interaction of lone pairs of H2S2, H2O2, and N2H4 for several dihedral angles are studied by the semi-empirical ASMO SCF method, and their dependencies on the dihedral angle is discussed. Also, the interaction of the lone pairs of diimides, N2H2, N2F2, and (CH3)2N2, the relative stability of the cis forms and of their trans form, and the electronic transition energies of these molecules are calculated. The stable forms of N2H2 and (CH3)2N2 are calculated to be of the trans form, but that of N2H2 is the cis form. An energy component analysis of these compounds has been made. The main factor in the lack of stability of the cis form of N2H2 is shown to be the core-core repulsion term, Vnn. On the other hand, in H2S2 and N2H4 not only the Vnn term but also the electrostatic interaction term, \oversetocc\underseti,jΣ(2Jij−Kji), contributes to their instability.
Cleaning Effects of the Reactant in the Liquid-phase Isomerization of m-Xylene over a Silica-Alumina Catalyst under Pressure
Authors: Takaya Haruo , Todo Naoyuki , Hosoya Tadasuke , Minegishi Toshio , Yoneoka Mikio , Oshio Hideki 
Published: July 2006

Abstract
The activity of silica-alumina catalyst in the isomerization of m-xylene was measured at the temperatures of 290°C, 320°C, 380°C, and 430°C in the liquid phase under a pressure of 300 kg/cm2. The observed activities were considerably higher than those in vapor-phase reactions, moreover even after 20 days practically no decline in the activity was observed except for the measurements at 430°C. This superior ability of the catalyst in the liquid phase can be ascribed to the cleaning effect of the liquid reactant: in the liquid-phase reaction the high-boiling by-product, which, in vapor-phase reactions, diminishes the activity because of its strong adsorptivity on the surface sites, is successively dissolved in the reactant; therefore, more surface sites are constantly available for the isomerization. This interpretation was substantiated by the following results: 1) when the reaction was operated in the liquid phase, about eighteen times as much high-boiling by-product was obtained as in the vapor phase; 2) the activity in the liquid-phase reaction was much higher than that in the vapor phase; 3) the decreased activity caused by the interruption of the flow was regenerable when the flow was resumed; 4) the addition of the high-boiling by-product to the reactant m-xylene resulted in a considerable decrease in the activity. In addition, the identification of the components in the high-boiling by-products was carried out by means of mass and NMR spectroscopic studies.
Topological Index. A Newly Proposed Quantity Characterizing the Topological Nature of Structural Isomers of Saturated Hydrocarbons
Authors: Hosoya Haruo 
Published: July 2006

Abstract
A topological index Z is proposed for a connected graph G representing the carbon skeleton of a saturated hydrocarbon. The integer Z is the sum of a set of the numbers p(G,k), which is the number of ways in which such k bonds are so chosen from G that no two of them are connected. For chain molecules Z is closely related to the characteristic polynomial derived from the topological matrix. It is found that Z is correlated well with the topological nature of the carbon skeleton, i.e., the mode of branching and ring closure. Some interesting relations are found, such as a graphical representation of the Fibonacci numbers and a composition principle for counting Z. Correlation of Z with boiling points of saturated hydrocarbons is pointed out.
Molecular Structure of Piperazine as Studied by Gas Electron Diffraction
Authors: Yokozeki Akimichi , Kuchitsu Kozo 
Published: July 2006

Abstract
A study of piperazine by means of gas electron diffraction has given the following structural parameters (the rg distances and the angles based on the rα structure) with estimated limits of error: C–C=1.540±0.008 Å, C–N=1.467±0.004 Å, ∠C–C–N=110.4±0.8°, ∠C–N–C=109.0±0.8°, C–H=1.110±0.008 Å and ∠H–C–H=109·1±5°; the molecule takes a chair conformation. The C–C distance is nearly equal to that in cyclohexane, and the C–N–C angle is slightly smaller than the C–C–N angle. These angles agree with those predicted by an SCF-CNDO/2 method.
A Fermi Resonance with ν6 of Acetonitrile
Authors: Matsuura Hiroatsu 
Published: July 2006

Abstract
The rotation-vibration spectrum of ν6 of acetonitrile measured by Nakagawa et al. has been reanalyzed by taking account of the Fermi resonance between the states |v6=1&gt; and |v7=1, v8=1&gt;. The previous assignment of Q branches by Amat et al. has been revised on the basis of the obtained values of band constants. The following band constants have been determined for the ν6 band: ν0=1447.9 cm−1, ζ=−0.305 and αA=0.046 cm−1. From the value of the resonance operator, the magnitude of the cubic force constant k678 has been estimated to be about 30 cm−1.
The Ruthenium-Catalyzed Hydrogenation of Aromatic Amines Promoted by Lithium Hydroxide
Authors: Nishimura Shigeo , Kono Yutaka , Otsuki Yoshiharu , Fukaya Yoshio 
Published: July 2006

Abstract
The effects of the addition of various alkaline substances on the ruthenium-catalyzed hydrogenation of aromatic amines have been investigated at raised temperature and pressure. The addition of lithium hydroxide was shown to be the most effective for rapid and selective hydrogenation of aromatic amines. The effect of various solvents on the hydrogenolysis of carbon-nitrogen bonds has also been studied in the hydrogenation of m-xylene-α,α′-diamine and N,N-dimethyl-p-phenylenediamine. Generally, the hydrogenation was fast and the amount of the hydrogenolysis was small in secondary alcohols. Typical examples of the syntheses of alicyclic amines are given.
The Chemical Behavior of Low Valence Sulfur Compounds. VII. The Oxidation of Ammonium Sulfide and Ammonium Sulfite with Compressed Oxygen in Aqueous Ammonia Solution
Authors: Naito Kunishige , Okabe Taijiro 
Published: July 2006

Abstract
The oxidation of ammonium sulfide and ammonium sulfite with compressed oxygen in aqueous ammonia soultion was studied in order to confirm the formation of ammonium sulfamate. Ammonium sulfite is easily oxidized to ammonium thiosulfate through polysulfides with oxygen and further to ammonium sulfamate and ammonium sulfate. Suitable conditions for producing ammonium sulfamate were found to be: initial concentration of ammonium sulfide 2.0 mol/l, temperature 100°C, concentration of ammonia 12 mol/l, concentration of cupric ion 0.1 mol/l and oxygen pressure 50 kg/cm2. Though ammonium sulfite is wholly oxidized to ammonium sulfate under the same conditions, it is partially oxidized to ammonium sulfamate besides sulfate in the presence of cupric ion under high concentration of ammonia. The mode of oxidation might differ from that of ammonium thiosulfate, ammonium sulfide and elemental sulfur because of no formation of polythionate as an intermediate.
Charge-Transfer Interaction and Fluorescence in Some Tetracyanobenzene Complexes
Authors: Kobayashi Takayoshi , Yoshihara Keitaro , Nagakura Saburo 
Published: July 2006

Abstract
Fluorescence lifetimes and quantum yields were measured for some tetracyanobenzene complexes with benzene and its methyl derivatives, and the radiative and nonradiative rate constants were determined under various conditions. The results show that the low fluorescence intensities of the complexes in nonpolar fluid media are due to small radiative rate constants and that nonradiative processes become important for the complexes in polar fluid media. From the theoretical consideration of the observed radiative transition probability, it is found that the geometry and the charge distribution in the excited equilibrium state are greatly different from those in the excited Franck-Condon state for the complexes in fluid media at room temperature and that the degree of the charge-transfer in the former state amounts to 96–100%, while it is only 12–45% in the latter state. The stabilization energy due to the reorientation was obtained from the temperature dependence of the fluorescence spectrum.
Effects of para-Substituents on the Rates of Inversion of Biphenyl Derivatives. I. 5,7-Dihydrodibenzo[c,e]thiepins
Authors: Oki Michinori , Iwamura Hiizu , Yamamoto Gaku 
Published: July 2006

Abstract
Several 3,9-disubstituted 5,7-dihydrodibenzo[c,e]thiepins were synthesized and temperature dependence of their NMR spectra was examined. All the substituted derivatives showed a lower energy barrier to inversion than the unsubstituted one. The effects of the substituents on the energy barrier may be interpreted in terms of resonance stabilization and/or out-of-plane bending of the axis bond at the transition state.
Molecular Structure and Phase-shift of Tetramethyllead as Studied by Gas Electron Diffraction
Authors: Oyamada Takeo , Iijima Takao , Kimura Masao 
Published: July 2006

Abstract
The molecular structure of tetramethyllead has been determined by the sector-microphotometer method of gas-phase electron diffraction. The structure parameters determined by a least-squares analysis on molecular intensities are, with estimated limits of error, as follows; rg(Pb–C)=2.238±0.009 Å, rg(Pb–H)=2.72±0.06 Å, rg(C···C)=3.66±0.07 Å, and rg(C–H)=1.08±0.02 Å. The experimental cut-off point was nearly 37 in q value for the 42.0 keV electrons; this was not in sufficient agreement with the theoretical value as calculated from the Thomas-Fermi-Dirac potential for Pb and from the Hartree-Fock potential for C. Moreover, the experimental background showed a significant deviation from its theoretical counterpart in the region of small q values. This discrepancy has not been accounted for even by the use of scattering factors based on a relativistic SCF calculation, or by the correction for the polarization effect available at present.