bluuebunny/crossref_metadata_2025 huggingface dataset:
An ESR Study of Intermediates in γ-Irradiated Methylcyclohexane and Isobutane Containing Benzene
Authors: Wakayama Terunobu , Miyazaki Tetsuo , Fueki Kenji , Kuri Zen-ichiro
Published: July 2006

The present work was undertaken in order to examine intermediates from benzene and toluene in γ-irradiated glassy methylcyclohexane (MCH) and polycrystalline isobutane matrices at 77°K. The γ-irradiation of MCH containing low concentrations of benzene gave an ESR spectrum with a good hyperflne resolution, which can be ascribed to the benzene anion, while at higher concentrations of benzene it gave an ESR spectrum with a poor resolution, which is attributable to the benzene monomer and dimer anions. On the contrary, the γ-irradiation of polycrystalline isobutane containing benzene did not yield an ESR spectrum which can be attributed to the benzene anion. However, the γ-irradiation of a mixed glass of isobutane and 4 mol% MCH containing benzene gave an ESR spectrum which is attributable to the benzene anion. The yield of trapped electrons in this system was three times as large as that in pure γ-irradiated MCH. Such a difference in the results between glassy MCH and polycrystalline isobutane matrices gives evidence of a phase effect on the radiolysis of solid hydrocarbon.
Electron Spin-Spin Interaction and Methylene Bond Angles in the Quintet Ground State of m-Phenylene-dimethylene Radicals
Authors: Higuchi Jiro
Published: July 2006

The effect of the methylene bond angles on the electron spin-spin interaction has been semiempirically investigated for the quintet ground states of the m-phenylene-dimethylene radicals, especially m-phenylene-bismethylene and m-phenylene-bisphenylmethylene. The D and E values calculated are compared with those observed, and the most probable structure, with a methylene bond angle near 140°, is estimated, as in the phenylmethylene radical.
The Chemical Modification of Biopolymers. III. The Introduction of SH Groups into Taka-amylase A
Authors: Suzuki Shuichi , Hachimori Yutaka , Matoba Ryuichi
Published: July 2006

The enzymic activity of Taka-amylase A on amylose, as measured by the blue-value method, increased to 180% of the original when one mole of mercaptosuccinyl group was introduced into one mole of the enzyme. Similar results were obtained for the activity measured by the Semogyi-Nelson method; the introduction of one or two mercaptosuccinyl groups raised the activity to 130–140% of that of the native enzyme. Even after the attachment of six mercaptosuccinyl groups per mole, the activity was 120% of the original. However, the enzymic activity was not elevated, but was lowered, by succinylation. When the sulfhydryl groups of the mercaptosuccinyl groups were blocked with p-chloromercurybenzoate or iodoacetamide, the enzyme was inhibited. These results suggest that the sulfhydryl groups of mercaptosuccinyl residues play an important role in increasing the enzymic activity.
Polyamino-Zucker. VI. Synthese von Derivaten der 2,3,4-Triamino-2,3,4-tridesoxy-β-d-glucose
Authors: Nakagawa Toshio , Sato Yoshikuni , Takamoto Tetsuyoshi , W. Lichtenthaler Frieder , Majer Norbert
Published: July 2006

A facile synthesis of methyl and phenyl glycoside derivatives of 2,3,4-triamino-2,3,4-trideoxy-β-d-glucopyranose is described, involving as the integral part the diamination with benzylamine or ammonia of 2,4,6-tri-O-acetyl-3-deoxy-3-nitro-hexosides of gluco- and galacto-configuration.
Preparation of Chromium(III) and Cobalt(III) Complexes with l-Leucine-N,N-diacetic Acid
Authors: Uehara Akira , Kyuno Eishin , Tsuchiya Ryokichi
Published: July 2006

l-Leucine-N,N-diacetic acid (abbreviated as LDA) and the complexes thereof were prepared as follows: K[Cr(OH)(lda)(H2O)]·3H2O (violet) (I), [Cr(lda)(H2O)2] (bluish violet) (II), [Cr(lda)(H2O)2]·2H2O (grayish violet) (III), (enH2)1⁄2[Cr(OH)(lda)(H2O)2] (green) (IV), [Cr(lda)(o-phen)]·2H20 (brownish orange) (V), K[Cr(lda)(acac)]·H2O (blackish violet) (VI) and K[Co(OH)(lda)(H20)]·H2O (bluish violet) (VII), where lda, en, o-phen and acac are the abbreviations of l-leucine-N,N-diacetate ion, ethylenediamine, o-phenanthroline and acetylaceto-nate ion, respectively. Except for Complex IV, LDA behaves as a quadridentate ligand. In Complex IV, it acts as a terdentate one. It was found from electronic absorption spectra that in Complex I, LDA behaves as a quadridentate in a solid state and as a terdentate ligand in an aqueous solution, whereas in cobalt(III) complex VII corresponding to I, LDA behaves as a quadridentate. Stepwise liberation of the coordinated water molecules in Complexes II and III could be detected by means of Derivatograph. Complex VII showed “Dehydration-Dimerization Reaction” upon being heated.
Alkoxysilanes. IV. Preparation of Alkoxysiloxy Derivatives of Titanium
Authors: Abe Yoshimoto , Kijima Ichiro
Published: July 2006

Alkoxysiloxy derivatives of titanium and polymeric substances with Ti–O–Si bonds were prepared. The reaction of titanium tetra-isopropoxide or bis (acetylacetonato)di-isopropoxytitanium with tri-t-butoxysilanol led to the formation of the derivatives of [(ButO)3SiO]nTi(OPri)4−n (n=2 and 3) and those of [(ButO)3SiO]2Ti(AcAc)2 respectively. In both of these series, the absorption peak of the Ti–O–Si bond in the IR spectrum shifted toward a lower wave number from the compounds of n=2 to those of n=3. The reaction of titanium tetra-isopropoxide with di-t-butoxysilanediol, as expected, gave a polymeric substance. In the reaction with bis(tri-t-butoxysiloxy)-silanediol, however, an unexpected cyclic compound consisting of the Ti–O–Si bond was obtained; its presence was confirmed by a study of the IR and NMR spectra, by elemental analysis, and by molecular-weight determination. In order to obtain a linear polymer, the reaction of the titanium acetylacetonato chelate with the silanediols was carried out to give a reddish-brown, highly viscous liquid or solid. These polymeric substances were soluble in common organic solvents and have an appreciable hydrolytic stability, but only a moderate thermal stability.
Anomalous Products Obtained by Nitration of Pentamethylbenzene, Pentaethylbenzene, and Some Mixed Penta-alkylbenzenes
Authors: Suzuki Hitomi , Nakamura Kiyomi
Published: July 2006

Pentamethylbenzene has been nitrated with fuming nitric acid to give mainly a mixture of nitropentamethylbenzene and 2,3,4,5-tetramethylbenzyl nitrate. Other isomeric nitrates were not formed in any significant amount. 6-Nitro-2,3,4,5-tetramethylbenzyl nitrate, 2,3,4,5-tetramethylbenzyl alcohol, 2,3,4,5-tetramethylbenzaldehyde, 2,2′,3,3′,4,4′,5,5′,6-nonamethyldiphenylmethane, and 2,2′,3,3′,4,4′,5,5′-octamethyl-6-nitroxymethyldiphenylmethane were the minor products. Pentaethylbenzene gave a mixture of nitropentaethylbenzene and α-methyl-2,3,4,5-tetraethylbenzyl nitrate along with some products of oxidation. Preferential side-chain attack occurred at the primary alkyl group ortho to the unsubstituted ring position. Thus, 1-methyl-2,3,4,5-tetraethylbenzene was found to give benzyl nitrate and α-methylbenzyl nitrate nearly in equal amounts, while 3-methyl-1,2,4,5-tetraethylbenzene was found to give them in an approximate ratio of 1 : 3. 1,3,4-Trimethyl-2,5-diisopropylbenzene underwent extensive nitrodealkylation, and 3,4-dimethyl-2,5-diisopropylbenzyl nitrate was the only side-chain substituted product identified.
Orientation of the Products from the Nitration of Halopentamethylbenzenes
Authors: Suzuki Hitomi
Published: July 2006

The action of fuming nitric acid upon chloropentamethylbenzene, bromopentamethylbenzene, and iodopentamethylbenzene has been investigated. 5-Halo-2,3,4,6-tetramethyl- and 6-halo-2,3,4,5-tetramethylbenzyl nitrate were the principal products. 4-Halo-2,3,5,6-tetramethylbenzyl nitrate was never formed in any significant amount. The orientation was consistent with the previously suggested mechanistic scheme. PMR spectral data for nine halotetramethylbenzyl chlorides and nitrates have been presented.
The Non-enzymatic Cleavage of Peptide Bonds. II. The Chemical Cleavage of the Tryptophyl Bond in Several Synthetic Peptides
Authors: Morishita Michiyo , Sakiyama Fumio
Published: July 2006

Several synthetic peptide derivatives containing tryptophan were examined for the selective cleavage at the tryptophyl residue, according to a new scheme involving ozonization and subsequent treatment with hydrazine. The ozonization reaction of the tryptophyl residue was carried out in the presence and in the absence of resorcinol in formic acid. Then the reaction of the ozonized product with hydrazine was performed at pH 3.6 to bring about the tryptophyl bond cleavage. The yield of the present cleavage reaction ranged from 35 to 68% on the basis of the starting peptide derivative used. The cleavage reaction could be followed spectroscopically in parallel with the exposure of the amino group acylated by the tryptophyl residue. The 2,3,4,5-tetrahydropyridazone derivative derived from the parental tryptophyl residue was identified by a comparison of both its chromato-graphic behavior and its ultraviolet spectrum with those of the standard sample. Thus it was confirmed that the present cleavage proceeded through the proposed reaction sequence.
Theory of Solvent Effects on Oscillator Strengths for Molecular Electronic Transitions
Authors: Abe Takehiro
Published: July 2006

A theoretical expression has been presented for an oscillator strength of an electronic transition in a solute molecule immersed in an isotropic dielectric continuum of solvent. It is assumed that a charged particle in the solute is subjected to a force due to a cavity field. The approximate expression derived on the basis of a quantum-mechanical perturbation theory has been successfully tested for nitrobenzene and acetone.
Measurement of the Hydrogen Ion Concentration in the Vicinity of the Anode during Electrodeposition of Water-Soluble Resin
Authors: Nakamura Yoshio , Komata Kimio , Nozaki Hiroshi
Published: July 2006

In order to make clear the mechanism of the electrodeposition of water-soluble resin, the hydrogen ion concentration in the vicinity of the anode during electrodeposition was measured using a quinhydrone reaction on platinum wire. The measured concentration of hydrogen ions in the vicinity of the anode was then compared with that of hydrogen ions which had been calculated according to the diffusion theory. The results show that the most of the hydrogen ions produced at the anode during electodeposition are consumed in the vicinity of the anode. This shows that there is apparently ionic combination of hydrogen ions with organic anions on the anode; this may lead to the deposition of organic anions.
Semi-empirical Unrestricted SCF-MO Treatment for Valence Electron Systems. II. The Angular Dependence of the Methyl Group hfs Constants
Authors: Nakatsuji Hiroshi , Kato Hiroshi , Yonezawa Teijiro
Published: July 2006

Since the spin-polarization contribution to the methyl-group hfs constant of the ethyl radical has been recognized to be important, the angular dependence of the β-proton hfs constants is re-examined for various radicals. Thus, the observed relation, Q(θ)=B0+B1cos2θ, is interpreted as being the sum of the following two equations.

& Q_SD(θ)=(B_1)_SDcos^2θ

& Q_sp(θ)=(B_0)_SP+(B_1)_SPcos^2θ,

where SD and SP denote the spin delocalization and spin polarization contributions respectively. θ is the rotational angle about C–C single bond. A molecular orbital description of the above angular dependences is also given.
Charge-Transfer Complexes of Maleic Anhydride and Dichloromaleic Anhydride with Various Aromatic Compounds
Authors: Kobayashi Takayoshi , Iwata Suehiro , Nagakura Saburo
Published: July 2006

Absorption, fluorescence and fluorescence excitation spectra were measured at room temperature and at low temperature for charge-transfer complexes containing maleic anhydride and dichloromaleic anhydride as electron acceptors. Benzene, toluene, mesitylene, durene, hexamethylbenzene, aniline, dimethylaniline, naphthalene and anthracene were used as electron donors. The charge-transfer absorption and fluorescence bands were observed for these complexes, their peak positions being linearly dependent upon the ionization potentials of donors for the same electron acceptor. From the comparison of the charge-transfer absorption or fluorescence peaks of maleic anhydride complexes with the corresponding values of dichloromaleic anhydride complexes, the difference in electron affinity between these two electron acceptors was obtained to be 0.4 eV. The electronic structures of the maleic anhydride complexes with benzene, naphthalene and anthracene were studied theoretically by considering the configuration interaction among the ground, locally-excited and charge-transfer configurations. The stable geometrical configurations in the ground and lower excited states of the complexes were discussed by the aid of the energy levels calculated for various relative orientations between electron donor and acceptor.
Stability of Tropolone Chelates of the Bi- and Tervalent Metal Ions
Authors: Hirai Michio , Oka Yoshinaga
Published: July 2006

The reaction of tropolone with several bi- and tervalent metal ions has been studied spectrophotometrically. Their stability constants (k1) have been found to be 7.40, 3.82, 3.06, 2.45, 7.46, 4.60, and 6.25 for Be(II), Mg(II), Ca(II), Sr(II), Y(III), Cd(II), and La(III) respectively, at 25±0.1°C and at an ionic strength of 0.10. A plot of logk1 against e2⁄r gave a straight line for all the non-polarizable metal ions except Be(II) and Mg(II). The logk1 values for all the polarizable metal ions are large. The correlation of logk1 with the second or the third ionization potentials for bi- and tervalent metal ions gave a fairly straight line.
Nitroalkenylferrocene. V. New Reactions of α-Halonitroolefins in the Presence of Sodium Alkoxides
Authors: Shiga Mikio , Tsunashima Masaaki , Kono Hiromichi , Motoyama Izumi , Hata Kazuo
Published: July 2006

The reactions of 1-iodo-2-ferrocenyl-1-nitroethylene (1) and β-bromo-β-nitrostyrene (5) with various sodium alkoxides were investigated. The reaction in the presence of an excess of alkoxides gave nitroketones, (2) and (6), and nitroacetals (3) and (7). The thermal decomposition of the nitroacetals in a nitrogen atmosphere afforded β-alkoxynitroolefins (8), which were found to be useful for obtaining asymmetric nitroacetals (9) with different alkoxy groups. The reaction mechanism was discussed by postulating the intervention of a nitrocarbene (12) and β-alkoxynitroolefin (8). The intermediacy of the nitrocarbene was supported by an experiment using vinylferrocene as a carbene scavenger.
Reactions of Nitrones with Free Radicals. II. Formation of Nitroxides
Authors: Iwamura Michiko , Inamoto Naoki
Published: July 2006

Reactions of N-t-butylaldonitrones with free radicals gave stable nitroxides, one of which was isolated in pure state. The stability of the nitroxides was explained by the steric effect around the nitrogen and α-carbon atoms. In the reaction of 5,5-dimethyl-Δ1-pyrroline N-oxide with AIBN, nitroxide was detected by ESR technique, and 1,3-adduct and ketonitrone were isolated from the reaction mixture. From the results, it was confirmed that nitroxide is the intermediate of the 1,3-adduct formation and that a radical first adds to the carbon atom and then adds to the oxygen atom of the nitrones.
Synthetic Reactions by Complex Catalysts. XVI. The Dimerization of Acrylonitrile and Acrylate by Means of the Metal-Isocyanide Complex
Authors: Saegusa Takeo , Ito Yoshihiko , Kinoshita Hideo , Tomita Shimpei
Published: July 2006

Acrylonitrile and acrylate were dimerized to 2-methyleneglutaronitrile and 2-methyleneglutarate respectively by the binary catalyst system of a copper compound and an isocyanide in the presence of a protic solvent such as t-butanol. Transition metal acetylacetonates, such as Fe(II and III), Co(II and III), and Ni(II), in combination with isocyanide were also effective for this dimerization. A mechanistic discussion has been presented.
The Chemistry of Americium. I. A Study of the Preparation of Am (V) and Its Behavior by Means of TTA Extraction
Authors: Hara Mitsuo
Published: July 2006

The method for preparing Am(V) in various solutions was investigated by utilizing the difference in extractability between Am(V) and Am(III) in an TTA-isobutanol extraction system; Am(III) was quantitatively extracted with 0.1m TTA in isobutanol from a 1m acetate buffer solution at a pH greater than 3, while the percentage of Am(V) extracted into the organic phase was increased substantially with an increase in the pH from 3 to 5. When the organic phase containing Am(V) was shaken with an aqueous phase having a proper pH value and composition, Am(V) was selectively stripped into the aqueous phase. The stability of the valency state of Am(V) in the perchlorate, the acetate, and the sulfate solutions was then studied by examining the variation in the percentage of americium extracted as a function of the standing time. The rate of change in the valency state in the acetate and the perchlorate media is very slow, while it is rather rapid in the sulfate medium. This difference may be attributable to the faster rate of the disproportionation reaction of Am(V) in the last medium than in the former two. By applying the above results, the chemical behavior of Am(V) in the aqueous solution was investigated by TTA extraction; it was found that Am(V) would be in the form of AmO2+ in the absence of a complexing reagent. By the addition of acetate ions, the step-by-step formation of the acetate complex of Am(V) was observed. The stability constants of [AmO2Ac] and [AmO2Ac2]− were determined to be (25.0±3.1) (mol/l)−1 and (12.8±1.2) (mol/l)−2 respectively.
Stereospecific Polymerization of Allyl Vinyl Ether by BF3·OEt2
Authors: Yuki Heimei , Hatada Koichi , Ohta Koji , Sasaki Takashi
Published: July 2006

The polymerization of allyl vinyl ether was carried out by means of BF3·OEt2. The reaction proceeded through the vinyl double bond, and a polymer with allyl ether side chains was obtained. The effects of the polymerization conditions on the stereoregularity of the polymer were studied by means of NMR spectroscopy using a spin decoupling technique. A highly isotactic polymer was obtained at −78°C in toluene. The isotacticity of the polymer decreased slightly with a rise in the reaction temperature and with an increase in the initial monomer concentration. When the reaction was carried out in a mixture of toluene and nitroethane, a marked decrease in the isotacticity and the solution viscosity of the polymer was observed with an increase in the amount of nitroethane. The solution viscosity of the polymer decreased with an increase in the polymerization temperature and the catalyst concentration, and increased with an increase in the initial monomer concentration. The reaction between the polymer and HBr in acetic acid yielded a ternary copolymer consisting of vinyl alcohol, vinyl acetate, and vinyl bromide units.
Syntheses of Optically Active α-Amino Acids from Esters of α-Keto Acids by Hydrogenolytic Asymmetric Transamination, A Solvent Effect
Authors: Harada Kaoru , Yoshida Takao
Published: July 2006

Optically active α-amino acids were synthesized from esters of α-keto acid azomethines by catalytic hydrogenation. Solvent effect of the reaction was studied and the possible steric courses are discussed.
Conformers and Intramolecular Hydrogen Bond of trans-2-Halocyclohexanols
Authors: Fujimoto Etsuko , Takeoka Yoshiko , Kozima Kunio
Published: July 2006

By infrared studies it has been ascertained that trans-2-halocyclohexanols possess two conformers, namely, the ee-isomer and the aa-isomer, both in the liquid and in a solution, while only the eeisomer exists in the solid. In a dilute solution the ee-isomer is more stable and exists exclusively in the form with an intramolecular hydrogen bond. The values of the energy difference between the two isomers are 1.3, 1.9, and 2.2 kcal/mol for the chloro-, the bromo-, and the iodo-derivative respectively. The magnitude of the frequency shifts of the O–H stretching bands increases in the order: Cl<Br<I. These facts show that the intramolecular hydrogen bond stabilizes the ee-isomer and that the strength of the hydrogen bond increases in the order: Cl<BrBr>I, while the delocalization energy due to the chargetransfer increases in the opposite order. Therefore, it can be concluded that the energy due to the charge-transfer contributes dominantly to the energy of the intramolecular hydrogen bond formed in the ee-isomer of trans-2-halocyclohexanols.
Corrosion Reaction of Iron in Phosphatizing Solution
Authors: Shirakawa Ryokai , Takeda Shiro , Umegaki Takao , Okabe Taijiro
Published: July 2006

An electrochemical investigation was made on the corrosion reaction of iron in phosphatizing solution to clarify the mechanism of the formation of phosphate coating. Polarization characteristic curves revealed the corrosion of iron to be under cathodic control implying that the formation of phosphate coating occurs thus under cathodic control. The corrosion rate increased considerably by the addition of KNO3 or KNO2 which is used as an accelerator in phosphatization. The formation of phosphate coating was much accelerated by cathodic polarization of iron, but repressed by anodic polarization and rotation of the iron electrode.
Thermal Annealing Behavior of the Recoil 57Co Formed by the Decay of 57Ni-Labeled Hexamminenickel(II) Complexes
Authors: Omori Takashi , Wu Shaw-Chii , Shiokawa Takanobu
Published: July 2006

Thermal annealing reactions of 57Co formed by the EC and β+-decay of the 57Ni-labeled hexamminenickel(II) halide complexes were investigated in detail by means of ion-exchange techniques. When the annealing is carried out at high temperatures, the chemical behavior of 57Co is remarkably affected by the thermal decomposition of the parent and daughter complexes. In the intrinsic annealing, however, the annealing curves have characteristic shapes and the plateau yields of 57Co(NH3)63+ ion are independent of the temperature, depending on the nature of the outer-sphere anion. The unusual oxidation reaction of the recoil 57Co(II) species is explained by the action of the crystal defects in the near-neighborhood of the recoil site.
Kinetic Studies of the Electron Transfer Reaction in Iron(II) and Iron(III) Systems. III. Complex Formation and Catalytic Action with Thiocyanate Ion in Dimethyl Sulfoxide
Authors: Wada Goro , Yoshizawa Noriko , Sakamoto Yoko
Published: July 2006

The formation constants K1 and K2 of the complexes Fe(NCS)2+ and Fe(NCS)2+ in dimethyl sulfoxide (DMSO) and the rate constants and the activation parameters of the electron transfer reaction between Fe(II) and Fe(III) in DMSO catalyzed by thiocyanate ion were measured. K1 and K2 are (8.4±0.9)×102  m−1 and (0.97±0.10)×102  m−1 at μ=0.1 m and 25°C, respectively. The apparent rate constant kapp is nearly independent of acid concentrations and increases markedly with total thiocyanate ion concentration. The rate constants k1and k2 of Fe2+-Fe(NCS)2+ and Fe2+-Fe(NCS)2+ systems are (2.24±0.35)×102  m−1sec−1 and (2.96±0.64)×103  m−1 sec−1 at μ=0.2 m and 25°C, respectively. ΔH1\eweq=8.9±1.0 kcal/mol and ΔS1\eweq=−17±3 cal/deg·mol are obtained from the temperature dependence of kapp. From a comparison with the data of cases catalyzed by Cl− and SCN− ions in water and DMSO, the present electron transfer reaction is deduced to proceed probably via the inner-sphere mechanism with the SCN− ion as a bridging ligand, similar to the Cl− ion-catalyzed reaction in DMSO.
Infrared Spectra of Pentacyanonitrosylmanganese (14NO and 15NO) Complexes
Authors: Miki Eiichi , Kubo Soto-o , Mizumachi Kunihiko , Ishimori Tatsujiro , Okuno Hisateru
Published: July 2006

The 15NO-complexes for K3[Mn(CN)5(NO)]·2H2O, K3[Mn(CN)5(NO)] and Ag2[Mn(CN)5(NO)] were prepared. By measuring and calculating the effect of the nitrogen isotope 15N on the infrared spectra, the Mn–N–O arrangement was found in all the complexes, and the absorption bands due to the skeletal vibrations between the manganese and the NO group were clearly assigned.
On the Growth Rate of Selenium Spherulite
Authors: Hamada Shuichi
Published: July 2006

The Radical growth rates of the selenium spherulites were measured by the microscopic method at temperatures ranging form 128.4°C to 192.3°C. The radial growth rate increased with an increase in the crystallization temperature up to about 180°C, reached a maximum value of 87.0 μ/min, and then decreased abruptly, judging form the observation of organic polymers at crystallization temperatures near their melting points. The process of the spherulite growth of selnium near the melting point could not be interpreted by only two elementary processes, that of the segmental jump and that of the formation of a two-dimensional nucleus of a critical size. The variation in the radial growth rate of selenium with the temperature was explained by considering the bond-breaking process as an elementary process. The estimated surface free energy at the liquid-crystal interface was 25.1 erg/cm2; this value was a reasonable one.
The Indirect Determination of Microamounts of Mercury(II) by Means of Dithizone Extraction and AC Polarography
Authors: Kambara Tomihito , Hara Minoru
Published: July 2006

It was found that dithizone in an aqueous alkaline solution shows sharp AC polarographic peaks; the indirect determination of mercury by means of these peaks was investigated. After the extraction of mercury(II) dithizonate into benzene, the excess dithizone was eliminated. Then the mercuric ion was stripped into the aqueous phase containing the iodide ion. The isolated dithizone in the benzene layer was back-extracted into the alkaline supporting electrolyte solution and the polarogram was recorded. By the present method, up to 30 μg of mercury can be determined.
The Effect of Solvents on the Adduct Formation of Uranyl Thenoyltrifluoroacetonate with Tributyl Phosphate
Authors: Akiba Kenichi , Suzuki Nobuo
Published: July 2006

Addition compound formation between uranyl bis-thenoyltrifluoroacetonate (UO2A2) and tributyl phosphate(S) was studied by a partition method, using uranium-237 as the tracer. The formula of the adduct complex was shown to be UO2A2·S. The solvent effect on the adduct formation constant was taken into account in connection with the activity; the activity coefficients of each species in various solutions were calculated from the molar volume and the solubility parameter. The formation constants based on the molar fraction, Kx, in a number of solvents were pre-estimated, employing logKx=7.08 in carbon tetrachloride as a reference. They are in agreement with the observed values. The formation constant in terms of activity was found to be constant logKS°=5.77±0.30. A correlation between the formation constants of the two adducts, UO2A2·S and ZnA2·S, was demonstrated.
Electronic Spectra of Phenanthrene Derivatives. Effect of Substitution
Authors: Akiyama Shuzo , Nakagawa Masazumi , Nishimoto Kichisuke
Published: July 2006

During the course of studies on the spectral regularities of linear conjugated systems bearing aromatic terminal groups (cf Tetrahedron Lett., 1964, 719; ibid., 1968, 1121; This Bulletin, 39, 2320 (1966); ibid., 40, 340 (1967)), we found that the free electron model (FEM) cannot explain the effect of substitution on the electronic spectrum of phenanthrene. In order to get further information the electronic spectra of forty-eight phenanthrene derivatives each bearing a substituent at 2-, 3-, or 9-positions have been examined, and it was found that the electronic spectra of these derivatives also cannot be explained on the basis of FEM. SCF-MO-CI calculation has been carried out on phenanthrylpoly-ynes and hydroxyphenanthrenes revealing that the discrepancy between the observation and the expectation from FEM in the behavior of La and Lb of phenanthrene derivative is attributable to a complex configuration interaction.
Sterically Controlled Syntheses of Optically Active Organic Compounds. XIV. Syntheses of Dipeptides from N-(α-Ketoacyl)-α-amino Acid Esters
Authors: Harada Kaoru , Matsumoto Kazuo
Published: July 2006

Optically active α-amino acids were synthesized from azomethines of N-α-ketoacyl-amino acid esters by catalytic hydrogenation. When optically active (S)-alanine was used, (R)-amino acyl-(S)-alanine ester was obtained. When alkyl groups of optically active (S)-amino acids in the N-α-ketoacyl-amino acid esters were larger than ethyl group, the configurations of newly formed amino acids were found to be (S). From these results possible steric courses of the asymmetric syntheses are discussed.
The Catalytic Dehydrogenation of Alcohols with Reduced Copper under Ultraviolet Light
Authors: Nakamura Shigeaki , Kawamoto Kazuaki
Published: July 2006

In order to investigate whether or not the dehydrogenation activity of the reduced copper is affected by ultraviolet light, the reaction of such alcohols as ethanol, 1-propanol, 2-propanol, and 1-butanol was carried out with reduced copper and ultraviolet light at 250°C. It was found that the conversion of alcohols and the yield of aldehydes were larger with the reduced copper under ultraviolet light than without the light, and that aldol condensation for the ethanol reaction was recognizable when the reduced copper catalyst was used without ultraviolet light.
Purity Determination of Organic Compounds by Time-temperature Freezing or Melting Curves with a Simplified Apparatus
Authors: Enokido Hisae , Shinoda Takako , Mashiko Yo-ichiro
Published: July 2006

A simplified apparatus has been constructed for determining the purity of organic compounds by time-temperature freezing or melting curves. The sample cell is small and the amount of the sample needed in only 0.2 ml or 2 ml. The thermometers used are a Shimadzu platinum resistance thermometer calibrated by the measurement of fixed points and a chromel p-constantan thermocouple calibrated against a standard platinum thermometer with a precision better than ±0.03°. Purities of several hydrocarbons were determined by measuring their freezing and melting curves.
The Catalytic Dehydrogenation, Dehydroxylation, and Dehydroxymethylation of Benzyl Alcohol. II. The Effects of Sodium Compounds as Additives
Authors: Ishige Masayoshi , Sakai Koji , Kawai Masatoshi , Hata Kazuo
Published: July 2006

The reaction of benzyl alcohol has been examined over stabilized nickel (S-Ni) catalysts which have been modified by treating the catalyst surface with solutions of sodium compounds; this has been done in order to obtain some information about the relation between the behavior of the molecule adsorbed on the metal catalyst and the chemical nature of the catalyst surface. On the basis of the fH, fCH3, and fCHO values, which were defined as representing the catalytic activity for the formation of benzene, toluene, and benzaldehyde respectively, the variation in the activity for each modified S-Ni was evaluated. The general aspects may be summarized as follows: (1) The reaction is generally retarded with an increase in the amount of a sodium compound which is adsorbed on the catalyst during the modification process. (2) When the modification is of a lower grade, the effect of additives on the catalytic activity represented by f values is in the following order: NaNO3<NaOH<Na2S2O3<NaI<NaBr<NaCl. (3) A proper amount of NaCl on the catalyst promotes the reaction. The increase in SH and SCH3 values, which were defined as representing the selectivity factors for the formation of benzene and toluene toward that of benzaldehyde, is roughly associated with the increase in the corresponding f values.
Decomposition of cis- and trans-α-Phenylcinnamoyl Peroxide and t-Butyl cis- and frans-α-Phenylperoxycinnamate. Stereochemistry of 1,2-Diphenylvinyl Radical
Authors: Wada Naoto , Tokumaru Katsumi , Simamura Osamu
Published: July 2006

Decomposition of trans- and cis-α-phenylcinnamoyl peroxide and t-butyl trans- and cis-α-phenylperoxycinnamate were carried out in solution and the products were determined. t-Butyl trans- and cis-α-phenylperoxycinnamate, on decomposition in carbon tetrachloride, gave mixtures of cis- and trans-α-chlorostilbene in the same cis to trans ratio at 110°C, but in different ratios at 80°C, the higher ratio being obtained from t-butyl trans-α-phenylperoxycinnamate. In the decomposition of trans- and cis-α-phenylcinnamoyl peroxide in various solvents at 60°C, the α-halostilbenes formed in carbon tetrachloride and bromotrichloromethane and the stilbenes produced in cumene, chloroform and triethylsilane were shown to be richer in the isomer of the same configuration as the peroxide decomposed. The stereochemical course of the reaction of the 1,2-diphenylvinyl radical generated from these peroxy-esters and peroxides is discussed.
The Thermal Rearrangement and Degradation of 2,3-Bis(alkylimino)oxetane
Authors: Saegusa Takeo , Taka-ishi Naotake , Ito Yoshihiko
Published: July 2006

The thermal rearrangement of 2,3-bis(alkylimino)oxetane (1) was investigated. At 200°C, 2,3-bis(secondary alkylimino)oxetane was converted into 3-imidazolin-5-one (8). 2,3-Bis(tertiary alkylimino)oxetane was stable at 200°C, but it was rearranged at 300°C to a cyclobutanone derivative (18). A mechanism involving the β-lactam intermediate (12) (17) formed by the Chapman rearrangement of 1 was proposed.
Radical Cations of Halogenated Tetrahydroxybenzene Diethylene Ethers
Authors: Asahara Teruzo , Sen\={o} Manabu , Teshirogi Takuma
Published: July 2006

It was observed that two newly-prepared substances, 3,6-dichloro- and 3,6-dibromo-1,2,4,5-tetrahydroxybenzene diethylene ether, underwent one-electron oxidation to afford the corresponding radical cations in concentrated sulfuric acid. Their electronic spectra and ESR spectra were recorded in a sulfuric acid and nitromethane-AlCl3 medium. The chloro-compound gives an ESR spectrum with a hyperflne structure, while the bromo-compound shows a spectrum without hyperflne splitting. Some different behavior was observed in several model compounds with similar structures.
The Anchoring Effect of the Fine, Powdery Copolymer of Glycidyl Methacrylate-Divinyl Benzene for Antioxidants in Polypropylene
Authors: Mizutani Yukio , Kusumoto Koshi , Hisano Shigeo
Published: July 2006

The anchoring effect of the fine, powdery copolymer of glycidyl methacrylate-divinylbenzene, blended in polypropylene, for phenolic antioxidants was studied by the oxygen absorption method and by studying the infrared spectrum. As a result, the anchoring effect was recognized, and it was confirmed that the effect came from the reaction between the phenolic hydroxyl groups of antioxidants and the epoxy groups of the fine, powdery copolymer and that, furthermore, the anchoring effect was related to the molecular structure of the antioxidants. It is interesting to note that these results suggests that polymeric antioxidants practically overcome the defect of the migration or the volatility observed on low-molecular-weight antioxidants.
The Effect of Pressure on the Rate of the Acid-catalyzed Hydration of Propylene
Authors: Takaya Haruo , Todo Naoyuki , Hosoya Tadasuke , Minegishi Toshio
Published: July 2006

In order to confirm whether a water molecule (or molecules) is held in a protonated activated complex by electrostatic interaction or by a partial valence bond, the pressure dependency of the activation volume, ΔV\ewq, for the hydration of propylene was measured at 180°C. The pressure effect on the rate of the hydration of propylene was studied in such dilute sulfuric acid solutions of a 0.0000108 mole fraction (0.00060n under S.T.P.) that the dielectric constant, D, and the density of pure water could be replaced for those of the reacting solution. The absolute value of the ΔV\ewq decreases steeply from 19 ml/mol at 300 kg/cm2 to 4 ml/mol at 5000 kg/cm2. The activation energies and entropies, obtained from the temperature dependency of the reaction rate, are 22.7 kcal/mol and −16.6 e.u./mol respectively at 1000 kg/cm2 and 21.9 kcal/mol and −17.0 e.u./mol respectively at 3000 kg/cm2. The ΔV\ewq is approximately proportional to the −∂D⁄D2∂p value, (D: dielectric constant of medium; p: pressure), which follows from the Krichevski equation; hence, it was concluded that the contraction of water around an activated complex by electrostatic interaction contributes to the ΔV\ewq and that a water molecule (or molecules) is held in the activated complex by electrostatic interaction. The case of a water molecule being held by a partial valence bond was discussed in terms of the molar volumes of the reactants.
A Theoretical Study of the Catalytic Activity of Group I Metal Salts in the Homogeneous Liquid-Phase Oxidation
Authors: Ohkubo Katsutoshi , Shimada Hidetoshi , Shiotani Yasuhiro , Okada Masahide
Published: July 2006

A theoretical consideration of the catalytic activity of group I metal salts, especially of lithium ones, for the homogeneous liquid-phase oxidation of hydrocarbons was developed by extended Hückel molecular orbital calculations, with particular reference to the interaction between the salts and molecular oxygen. We made several findings. First, a marked activity of lithium salt-catalysts was reflected by a remarkable “electron-partial occupation” of the lithium cation in their salts. Second, a strong interaction of the lithium catalyst with O2 occurred at the angle of 15° to the direction of the 1πg-orbital expansions of O2. Third, the lithium catalyst participated strongly in the activation of O2 at the distance of 2 Å–3 Å, increasing the electron-population of one oxygen atom located farther from the lithium cation. Finally, the contribution of the “activated” oxygen molecule to the initiation of the oxidation of hydrocarbons was discussed.
ESR Study of Adsorbed Monomer and Dimer Cation Radicals of Benzene and Its Methyl Derivatives
Authors: Nagai Siro , Ohnishi Shun-ichi , Nitta Isamu
Published: July 2006

Benzene, toluene, o-, m-, p-xylene, and mesitylene adsorbed on silica gel were γ-irradiated at −196°C. ESR spectra observed at −196°C for these systems at low contents of the methylbenzenes were assigned to the respective monomer cations. Dimer cations of benzene, toluene, and p-xylene were produced on γ-irradiation at −196°C of the adsorbed systems at higher contents and also by the reaction of monomer cations and neutral molecules at higher temperature than −160°C.
Conformation of Adsorbed Polymeric Chain. III
Authors: Motomura Kinsi , Sekita K\={o}j\={u} , Matuura Ryohei
Published: July 2006

Average properties of a copolymeric chain in which a segments of the kind A and b segments of the kind B occur alternatively are calculated for an infinite chain length. For the simplest case of a=b=1, i.e. an alternating copolymeric chain (–A–B–)N, the average number of adsorbed segments of A, \barνA, that of B, \barνB and the mean square end-to-end distance \barr2 are computed numerically as functions of the adsorption energies εA and εB. The values of \barνA, \barνB, and \barr2 are proportional to N for larger values of ηA (=exp(εA⁄kT)) than the critical value (ηA)c at fixed ηB, as found for the case of a homogeneous polymeric chain. It is seen that the behavior of the copolymeric chain near an interface is affected distinctively by the adsorption energies of the segments A and B, and the copolymeric chain is forced to adsorb even for a fairly low adsorption energy of the segment of one kind if the adsorption energy of the segment of the other kind is sufficiently large.
Some Information Derived from the Infrared Spectra of Ionradical Molecules. The Spin-density Distribution for the p-Chloranil Anion Radical
Authors: Iida Yôichi
Published: July 2006

The spin-density distribution in the p-chloranil anion radical was determined by means of the difference in the bond orders of the conjugated systems between p-chloranil and its anion radical, which was estimated on the basis of the stretching force constants. It was found that the spin-density distribution calculated by this method was in good agreement with that estimated by means of the molecular orbital calculations or by means of the hyperfine splitting constants in the ESR absorption. In view of these results, it was suggested that the present method might become a new tool for investigating the unpaired electron distributions of ion-radical molecules in general.
The Adsorption of Water on SiO2, Al2O3, and SiO2·Al2O3. The Relation between the Amounts of Physisorbed and Chemisorbed Water
Authors: Morimoto Tetsuo , Nagao Mahiko , Imai Junichiro
Published: July 2006

The specific surface area, the water content, and the water adsorption isotherm have been measured in order to investigate the interaction between the surfaces of SiO2, Al2O3, and SiO2·Al2O3 and water molecules. Al2O3 gives II-type adsorption isotherms and the amount of adsorbed water on it increases with a rise in the temperature of pretreatment, whereas SiO2 gives isotherms approximate to the III-type and the amount of adsorbed water is larger when treated at lower temperatures. With SiO2·Al2O3, it was found that the type of isotherms and the effect of the pretreatment temperature are similar to those of Al2O3, and that the amount of adsorption increases with an increase in the Al2O3 content. By analysing the adsorption data, the ratio of the amount of physisorbed water in the first layer to the amount of the underlying chemisorbed water was calculated. As a result, it was found that the H2O:OH ratio is 1:2 on the surface of Al2O3, whereas it is 1:1 on the surface of SiO2. The analysis of the isotherms on SiO2·Al2O3 showed that the adsorption property of water on them is not additive: e.g., the amount of adsorbed water on SiO2·Al2O3 is larger than the sum of the water adsorbed on each component. Thus, it has been concluded that, on the surface of SiO2 in contact with Al2O3, the surface hydroxylation proceeds more rapidly than on the surface of pure SiO2.
Electron-Transfer Reactions of Multidentate Ligand Cobalt(III) Complexes. I. The Reductions of Some Chloro(triethylenetetramine)cobalt(III) Complexes by Iron(II)
Authors: Kurimura Yoshimi , Ohashi Kousaburo , Ohtsuki Toshio , Yamamoto Katsumi
Published: July 2006

The kinetics of Fe2+ reductions of cis-α-Co(trien)Cl2+, cis-α-Co(trien)OH2Cl2+ and cis-β1-Co(trien)OH2Cl2+(trien=triethylenetetramine) have been studied at 25°C, [H+]=0.10 m and Σ[ClO4−]=1.0 m. The second-order rate constants obtained are 4.0×10−4  m−1 sec−1, 1.6×10−4  m−1sec−1, and 9.8×10−5  m−1 sec−1 for cis-α-Co(trien)Cl+2, cis-α-Co(trien)OH2Cl2+, and cis-β1-Co(trien)OH2Cl2+ respectively. It is demonstrated, by comparing with other rate data for the Fe2+ reductions of cis-CoN4XCln+ (N=NH3, 0.5 en and 0.25 trien, and X=H2O and Cl−) that the rate decreases with an increase in the number of chelate rings in the Co(III) complexes. The chelate effect of the nonbridging ligand on the electron-transfer reactions of Co(III) complexes is discussed on the basis of a model which involves the ligand-field strength of the trans-ligand to the bridging one, the energy needed for stretching the trans-group away from the Co(III) center, and the effect of the solvation.
The Reaction of Acetylenecarboxylic Acid with Amines. XV. Reaffirmation of the Enamine Structure Facilitated by Intramolecular Hydrogen Bonding Common to the Reaction Products
Authors: Iwanami Yasuo
Published: July 2006

The reactions of dimethyl acetylenedicarboxylate (V) with p-chloroaniline, ethanolamine, ethylenediamine, o-aminophenol, and o-phenylenediamine gave dimethyl N-(p-chlorophenyl)aminofumarate(VI), 3-methoxycarbonylmethylene-3,4,5,6,-tetrahydro-2H-1,4-oxazin-2-one (VII), 3-methoxycarbonylmethylenepiperazin-2-one (VIII), 3-methoxycarbonylmethylene-3,4,-dihydro-2H-1,4-benzoxazine-2-one(IX), and 3-methoxycarbonylmethylene-3,4-dihydro-2(1H)-quinoxalinone(X), respectively. It has been shown that methoxycarbonylmethylene is a common structural element in all products, where the carbonyl is hydrogen-bonded with an amino group to form an enamine form. The spectra measured for crystals (IR) and for solutions in inert solvents (NMR) exhibited the fixation of the enamine form preferentially to the imine form, while NMR spectra for trifluoroacetic acid solutions indicated both forms in equilibrium. Tautomerization occurring in the acid is discussed.
Side-chain Nitrooxylation of Polyalkylbenzenes through Ionic Process
Authors: Nakamura Kiyomi
Published: July 2006

The reaction of polyalkylated aromatic compounds with fuming nitric acid has been investigated with respect to the effects of substituents and added electrolytes on the ease and extent of the concurrent side-chain nitrooxylation and nuclear nitration. Relative reactivity of substituted pentamethylbenzenes C6(CH3)5X for side-chain substitution decreases from 1 to 2×10−2 to 4×10−4 to 3×10−6 with the change of substituent groups from methyl to hydrogen to bromine to nitro in accordance with the ionic character of the reaction. Added electrolytes have profound influence on the reaction rates, but the ratio of products from side chain nitrooxylation and nuclear nitration remains almost unchanged, indicating that both processes share a common intermediate. The relative amount of side-chain substitution depends closely on the positional relationship of alkyl groups in the nucleus, and preferential formation of p-alkylbenzyl nitrates is always observed. It is concluded from the results, that the side-chain nitrooxylation products are formed by way of the polar intermediate common with the ring nitration products. Some plausible reaction sequences are briefly discussed.
Asymmetric Hydrogenation of C=O Double Bond with Modified Raney Nickel. XVIII
Authors: Izumi Yoshiharu , Ohkubo Kazuo
Published: July 2006

The asymmetric activities of the catalysts modified with l-α-amino and l-α-hydroxy acids, which have two asymmetric centers on α, β and α, γ-carbons were studied, and the participation of the β- and γ-configurations to the asymmmetric activity of the catalyst was made clear. It was found that the S:β-configuration and the S:γ-configuration increase the asymmetric activity of the + and − directions respectively.
Conformational Changes in Heterocyclic Analogs of Metaparacyclophane
Authors: Akabori Sadatoshi , Shiomi Kengo , Sato Takeo
Published: July 2006

Sulfur analogs of [2.2]metaparacyclophane, II, III, and IV were prepared and their NMR spectra were examined. Of the three possible inversion mechanism, the one which involves the inversion of the m-phenylene unit is proposed.
Studies on Aminosugars. XXVI. A New Method for the Simultaneous Protection of Amino and Hydroxyl Groups in Aminosugars and Aminocyclitols
Authors: Umezawa Sumio , Takagi Yasushi , Tsuchiya Tsutomu
Published: July 2006

2-Deoxystreptamine-1,6:3,4-dicarbamate (II), methyl 2-amino-2-deoxy-α-d-glucopyranoside-2,3-carbamate (VIII) and methyl 6-amino-6-deoxy-α-d-glucopyranoside-4,6-carbamate (X) were prepared by utilizing p-nitrophenoxycarbonyl chloride or phenoxycarbonyl chloride.
Studies of Peptide Antibiotics. XXIII. Syntheses of Linear Decapeptide Analogs with Gramicidin S Sequence
Authors: Makisumi Satoru , Waki Michinori , Izumiya Nobuo
Published: July 2006

Six linear decapeptides having the same sequence of amino acids of gramicidin S, wherein the N-terminal amino acid is acylated with formyl or acetyl group, the C-terminal amino acid is in a form of its amide or ethanolamide and the N,C-terminal ones are free, were synthesized to obtain a more reliable picture of the cyclic structure to the antibacterial activity of gramicidin S. All these linear decapeptide analogs were found to be active to some extent against several microorganisms.