Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 65 , Issue 4
Showing 1-50 articles out of 57 articles from the selected issue
  • Kouta Fukui, Tsutomu Nonaka
    1992 Volume 65 Issue 4 Pages 943-948
    Published: 1992
    Released: July 14, 2006
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    The halogenating power of Br–Cl composite species (termed “BC-reagent” in this article) generated anodically from mixtures of Br and Cl in CH2Cl2 was examined in an ex-cell manner toward some organic compounds. The BC-reagent brominated methoxybenzenes, and the brominating power could be precisely controlled by means of the amount of electricity charged and by varying the ratio of Cl/Br. The power of the reagent was less controllable during the bromination of aniline. The reaction of olefins with the BC-reagent led to dibromination and bromochlorination, the product-selectivity of which could be also controlled. The theoretically calculated chemical composition of the BC-reagent agreed fairly well with the experimentally confirmed value in some cases.
  • Yukio Nagasaki, Shinya Morishita, Masao Kato, Yasuharu Kihara, Teiji T ...
    1992 Volume 65 Issue 4 Pages 949-953
    Published: 1992
    Released: July 14, 2006
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    Kinetic studies concerning the addition reactions of lithium diethylamide (Et2NLi) to several vinylsilane derivatives, such as H2C=CH–Si(CH3)2X [X: methyl, phenyl, ethoxy, 2-(diethylamino)ethyl and vinyl], and H2C=CH–Si(CH3)2OSi(CH3)2X [X: 2-(diethylamino)ethyl and vinyl], were carried out. The reactivity of vinylsilane derivatives toward nucleophile was strongly influenced by the nature of the substituents on the Si atom. The reactivity of trimethylvinylsilane [rate constant k (trimethylvinylsilane; cHx; 50 °C) = 2.9 ± 0.2 · 10−4 dm3 mol−1 s−1] was found to be of the same order of magnitude as that of para-alkyl-substituted styrenes, such as 4-methylstyrene [k (4-methylstyrene; cHx; 50 °C) = 3.2 · 10−4 dm3 mol−1 s−1]. The reactivities of vinylsilane compounds having an aryl substituent, e.g. dimethylphenylvinylsilane [k (dimethylphenylvinylsilane; cHx; 50 °C) = 14.8 ± 0.3 · 10−4 dm3 mol−1 s−1] and dimethyldivinylsilane [k (dimethyldivinylsilane; cHx; 50 °C) = 14.8 ± 0.6 · 10−4 dm3 mol−1 s−1], were higher than that of trialkyl-substituted vinylsilane. This fact may be explained by a π-conjugation between the phenyl (or vinyl) and vinyl groups through an empty d-orbital of the Si atom. A vinylsilane compound having a 2-(dialkylamino)ethyl substituent, [2-(diethylamino)ethyl]dimethylvinylsilane, showed unique reactivity toward lithium diethylamide, indicating that the β-nitrogen atom plays an important role regarding the reactivity of the vinyl group. In the reaction between lithium diethylamide and vinylsilane having an ethoxyl group, an addition reaction to the vinyl group and a cleavage reaction of the Si–O linkage proceeded concurrently. No cleavage reaction, however, proceeded in the reaction of lithium diethylamide with vinylsilane compounds having a disiloxane linkage. 1,1,3,3-Tetramethyl-1,3-divinyldisiloxane exhibited a much higher reactivity than did the other vinylsilane compounds.
  • Toyoshi Shimada, Kiyoko Nakanishi, Kensaku Morihara
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 954-958
    Published: 1992
    Released: July 14, 2006
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    Footprint catalysts are silica(alumina)gel catalysts with tailored specificities. Their catalytic sites are “molecular footprint-like” cavities formed by a molecular imprinting procedure with templates, which are referred to as transition-state or reactive-intermediate analogs of the catalyzed reactions. To clarify the relationship between the structural feature of template molecules and catalytic behavior, seven footprint catalysts were prepared by imprinting with templates of several types closely related to the substrates, benzoic anhydride and acetic anhydride; their catalytic activity and thermodynamic parameters for 2,4-dinitrophenolysis were then estimated. Among these catalysts, a catalyst imprinted with N,N′-dibenzoylbenzenephosphonediamide, a tetrahedral intermediate analog for benzoic anhydride substrate, showed a 10-fold higher catalytic activity than did the other imprinted catalysts.
  • Nobujiro Shimizu, Fumie Hayakawa, Yuho Tsuno
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 959-964
    Published: 1992
    Released: July 14, 2006
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    The rates of solvolysis of 1-(pentamethyldisilanyl)-, 1-trimethylsilyl-, and 1-methyl-substituted 2- phenylcyclopropyl bromides (4a, 4b, and 4c) were measured in 2,2,2-trifluoroethanol at 100 °C: The relative rates for trans-4a, trans-4b, and trans-4c were 3.48 : 1.0 : 10.7, respectively; the trans/cis isomeric rate ratios (kt/kc), which were determined by competition experiments, were 2.99 for 4a and 1.70 for 4b. The solvolysis of trans-4b yielded only open allylic ethers, consistent with a σ-assisted mechanism (kΔ); the trans-4a predominantly, however, gave a cyclopropyl ring-retained compound, dimethyl[trans-2-phenyl-1-(trimethylsilyl)cyclopropyl](2,2,2-trifluoroethoxy)silane, indicative of σ-unassisted (kc) solvolysis.
  • Tadashi Shiraiwa, Shinji Sakata, Hisashi Natsuyama, Keiko Fujishima, H ...
    1992 Volume 65 Issue 4 Pages 965-970
    Published: 1992
    Released: July 14, 2006
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    The racemization rates of N-acetyl-(S)-tyrosine, N-acetyl-(S)-phenylalanine, N-acetyl-(R)-2-(4-hydroxyphenyl)glycine [(R)-AcHpg], N-acetyl-(R)-2-phenylglycine, and N-acetyl-(S)-alanine were measured by use of (RS)-α-methylbenzylamine [(RS)-MBA] as a base-catalyst. The first-order rate constant for racemization tended to increase with an increase in the polar substituent constant of the N-acetylamino acid side chain. The racemization appeared to be subject to the inductive effect by the side chain. An asymmetric transformation of (RS)-AcHpg by using (R)-MBA, based on the result of racemization, gave an optically pure salt of (R)-AcHpg with (R)-MBA by successive use of the filtrate as the solvent. Optically pure (R)-2-(4-hydroxyphenyl)glycine [(R)-Hpg] was separated from the salt in 87–90% yield based on the starting (RS)-AcHpg. In addition, the asymmetric transformation of (R)-AcHpg was achieved by using (S)-MBA to give optically pure (S)-Hpg in 80% yield after purification of the salt of (S)-AcHpg with (S)-MBA followed by hydrolysis.
  • Nobujiro Shimizu, Sho-ichiro Matsuno, Masayuki Tanaka, Yuho Tsuno
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 971-977
    Published: 1992
    Released: July 14, 2006
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    Stereochemistry in amine-promoted enol trimethylsilylation of meso- and dl-α,α′-dichloro ketones, RCHClCOCHClR (1a; R = Me and 1b; R = i-Pr), and in ketonization of the resultant enol silyl ethers (2a and 2b) has been studied. The Et3N-promoted silylation of 1 in benzene shows a marked diastereoselectivity; the racemic isomer exhibits 84% and 98% (E)-selectivities for 1a and 1b, while the meso isomer, 97% and 98% (Z)-selectivities respectively. Both stereo- and diastereo-selectivities markedly depend upon solvent polarity and base strength. For example, both meso- and dl-1a showed small (Z)-selectivities in DMF. The diastereoselectivity markedly decreased with increasing base strength; both 1a and 1b exclusively gave the (E)-isomer of 2 irrespective of the configuration of the ketone when treated with lithium diisopropylamide in the presence of chlorotrimethylsilane at −78 °C. The ketonization of 2a and 2b was also diastereoselective in the direction opposite that observed in the forward reaction; the (E)-isomer predominantly gave the meso ketone (24% d.e.), while the (Z)-isomer, the racemic ketone (ca. 70% d.e.) upon protonation with concd hydrochloric acid in THF.
  • Yoshio Nishimura, When-mei Wang, Toshiaki Kudo, Shinichi Kondo
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 978-986
    Published: 1992
    Released: July 14, 2006
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    The enantioselective synthesis of siastatin B, an inhibitor of neuraminidase and its antipode from D-ribono-γ-lactone has stereospecifically been achieved. The total synthesis elucidated the absolute configuration of siastatin B as (3S,4S,5R,6R)-6-acetamido-4,5-dihydroxy-3-piperidinecarboxylic acid.
  • Xian-Yong Wei, Eisuke Ogata, Etsuo Niki
    1992 Volume 65 Issue 4 Pages 987-990
    Published: 1992
    Released: July 14, 2006
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    Hydrocracking of di(1-naphthyl)methane (DNM) in the temperature range of 150–300 °C was studied. In the presence of FeS2 and pressurized hydrogen, DNM hydrocracking took place over 175 °C. FeS2 selectively catalyzed the cleavage of C–C linkage in DNM to give 1-methylnaphthalene and naphthalene. The rate for DNM hydrocracking strongly depended on hydrogen pressure, FeS2 feed and reaction temperature. Kinetic study indicates that DNM hydrocracking in the temperature range of 200–300 °C could be considered as a first order reaction. Under the reaction condition (DNM 7.5 mmol, decalin 30 ml, FeS2 0.5 g, sulfur 0.05 g, initial hydrogen pressure 10 MPa), the activation energy and frequency factor for DNM hydrocracking were 19 kcal mol−1 and 5.3 × 107 h−1, respectively.
  • Norikazu Nishino, Ming Xu, Hisakazu Mihara, Tsutomu Fujimoto
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 991-994
    Published: 1992
    Released: July 14, 2006
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    The rates of cyclization-cleavage of dipeptides with various sequences assembled on the Kaiser’s oxime resin were determined. cyclo(–Ala–Ala–) was liberated from the H–Ala–Ala–oxime resin with the apparent first-order rate constant, kapp, 1.8 × 10−1 min−1 under basic conditions. While cyclo(–Ala–Pro–) was much more rapidly formed (kapp = 1.5 min−1) from the H–Ala–Pro–resin, cyclo(–Ala–Val–) was produced with kapp, 2.2 × 10−2 and 5.5 × 10−2 min−1 from H–Ala–Val–resin and H–Val–Ala–resin, respectively. During the coupling reaction for tripeptides by the dicyclohexylcarbodiimide/1-hydroxybenzotriazole or the symmetrical anhydride method was observed significant loss of dipeptides by cyclization, which was successfully prevented by the [(benzotriazol-1-yl)oxy]tris(dimethylamino)phosphonium hexafluorophosphate (BOP) method except in the case of H–Ala–Pro–resin. In consequence of elucidating the defect and describing the method for the prevention, the reliability of the oxime resin was increased to be widely used in the practical synthesis of protected peptides.
  • Tadao Kenjo, Yukiyasu Yamakoshi
    1992 Volume 65 Issue 4 Pages 995-1001
    Published: 1992
    Released: July 14, 2006
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    The transient depolarization curves of Pt/ZrO2 high temperature air cathodes have been measured and compared with theoretical curves calculated by assuming a diffusion mechanism of atomic oxygen. The decay equation used involves the limiting current density, time constant for the decay rate and effective reaction area, as parameters to be determined. These parameter values were obtained by curve fitting. The polarization loss was found to decrease with increasing O2 pressure at the rate expected from the diffusion mechanism. The performance of the electrodes was enhanced as the sintering temperature rose. This trend was reflected on an increase in the parameter of effective reaction area. The performance was improved by loading an excess current. This effect was explained as being due to an increase in the diffusivity of Oa.
  • Kozo Inuzuka, Akira Fujimoto
    1992 Volume 65 Issue 4 Pages 1002-1005
    Published: 1992
    Released: July 14, 2006
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    In order to ascertain the formation processes of the tautomer and proton-transferred complexes in the 2-aminopyridine–acetic acid system in the ground state, a molecular orbital calculation was carried out for the 2-aminopyridine–formic acid system by the ab initio STO-3G method with full-geometry optimization of the complex. The following conclusions were drawn from the present calculation: (1) The amino–imino tautomerization in the 2-aminopyridine–formic acid system proceeds through a double proton transfer process between 2-aminopyridine and formic acid. (2) The formation of a proton-transferred complex in the 2-aminopyridine–formic acid system is difficult in the ground state. This conclusion may be applicable to the 2-aminopyridine–acetic acid system. (3) In the case of the ab initio STO-3G calculation a full-geometry optimization of the complex plays an important role in elucidating the stabilization energies and geometries of the tautomer and proton-transferred complexes. (4) A full-geometry optimization of the complex model is not so important for evaluating the hydrogen bond energy of the stable hydrogen-bonded complex, but is necessary for elucidating the effect of hydrogen bond formation on the molecular geometry of the complex. (5) The bisectal angle of the NH2 group, calculated by the ab initio STO-3G method, becomes much larger than the experimental value. Further, the energy difference between the planar and pyramidal 2-aminopyridine with respect to the NH2 group is much larger than the experimental value.
  • Masaki Yamada, Yoshihito Tanaka, Yasuyuki Yoshimoto, Shigeyasu Kuroda, ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1006-1011
    Published: 1992
    Released: July 14, 2006
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    A heteroaromatic compound 3,6-diaminodipyrido[3,2-a: 2′,3′-c]phenazine was synthesized with an improved method to convert 1,10-phenanthroline derivatives to the corresponding 5,6-diones. It was shown that the electron-donating effects of amino substituents were extended not only to pyridine rings but also to the phenazine ring.
  • Isao Yoshida, Nobuhiro Yamamoto, Fumio Sagara, Daido Ishii, Keihei Uen ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1012-1015
    Published: 1992
    Released: July 14, 2006
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    The acid dissociation constants of the hydroxyl groups in tetrasodium 25,26,27,28-tetrahydroxycalix[4]arene-5,11,17,23-tetrasulfonate (CALX-S4) were determined at 25 °C by potentiometric and spectrophotometric titration methods. The first acid dissociation constant(pKa1) was found to be 3.26 ± 0.02 (μ = 0.1 with KNO3), which demonstrated a remarkable pKa shift due to intramolecular hydrogen-bonding interactions among the hydroxyl groups in CALX-S4. On the other hand, considerably weak acidities were observed on the residual three hydroxyl groups of CALX-S4 (pKa2 = 11.8 ± 0.3 (μ = 0.1 with KNO3), 11.3 ± 0.3 (μ = 2.0 with KCl), pKa3 = 12.8 ± 0.3 (μ = 2.0 with KCl), and pKa4= ca. 14 (μ = 2.0 with KCl)).
  • Takayoshi Suzuki, Junnosuke Fujita
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1016-1025
    Published: 1992
    Released: July 14, 2006
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    A series of dinuclear complexes containing Me2Ppy ( = 2-(dimethylphosphino)pyridine) as a bridging ligand, [MM′X2(μ-Me2Ppy)2] (M, M′ = Pd(I), Pt(I); X = Cl, Br, and I), have been prepared by reactions between [MX2(Me2Ppy-P)2] and [M′2(dba)3] (dba = 1,5-diphenyl-1,4-pentadien-3-one). In these reactions it has been found by 31P{1H} NMR studies that a dimeric head-to-head isomer was formed in the first place and then isomerized to a head-to-tail isomer. The reactions for analogous Ph2Ppy ( = 2-(diphenylphosphino)pyridine) complexes have been also examined in the same manner. The monomeric Pd(II) complexes reacted more rapidly than did the corresponding Pt(II) complexes in these dimerization and isomerization reactions. For each halogeno series of the Me2Ppy and Ph2Ppy complexes, it seems that the dimerization occurs faster in the order of Cl < Br < I, while the order is reversed in the isomerization, Cl > Br > I. The Me2Ppy complexes isomerized to a head-to-tail isomer more rapidly than did the Ph2Ppy complexes, indicating a larger trans effect of Me2Ppy than Ph2Ppy.
  • Murlidhar D. Patil, Gopal N. Natu, Shantaram B. Kulkarni
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1026-1032
    Published: 1992
    Released: July 14, 2006
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    Thermogravimetric analysis, TGA, of cobalt(II)bromide, [Co(NH3)6]Br3 –henceforth referred to by the shortname HCBR– was carried out using a wide diameter short one and a narrow diameter long sample cups. In the former type of cup the TGA trace was similar to that reported one. However, when the latter cup was used, the TGA showed oscillations in the % weight-loss. Cobalt(II)bromide, CoBr2, is formed as an intermediate product in the thermal decomposition of HCBR. The oscillatory nature of weight-loss curve was studied for both HCBR and CoBr2.
    The oscillatory behavior in the present system has been confirmed on the basis of the following experiments:
    (a) Dynamic TGA and differential thermal analysis, DTA, of HCBR and CoBr2·2H2O.
    (b) Isothermal TGA by weight-loss method for HCBR and CoBr2.
    (c) Thermal decomposition studies, in closed system, of (i) CoBr2 and of (ii) CoO in a mixture of O2 and Br2 gases, and of a mixture of (iii) Co3O4 and CoBr2 in dry nitrogen.
    The oscillations in the composition of the solid residue were attributed to the formation of CoOBr as an intermediate. Final product of thermal decomposition of CoBr2 in air is Co3O4. Hence it is possible to imagine that the point of CoOBr formation makes branching off point. This sets the reaction to oscillate in the composition domain. Therefore, it was thought that Edelstein mechanism would be operative in this reaction. Alternately, the population growth model may also be used to explain this observation. Formation of CoOBr was thought to be the weight-loss step, i.e. decrease in the ‘population’ of CoBr2, while the formation of CoBr2 was the weight-gain step, i.e. increase in the ‘population’ of CoBr2 under the proposed reaction, CoBr2 + 1/2O2 CoOBr. The purpose of this article is, therefore, to present the interesting facts of this reaction before the readers, and not to ascribe any particular model for its explanation.
  • Rakam Singh Chauhan, Lajpat Rai Kakkar
    1992 Volume 65 Issue 4 Pages 1033-1037
    Published: 1992
    Released: July 14, 2006
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    A very simple and rapid method for the extractive separation and photometric determination of vanadium is worked out using benzoylacetone as a complexing reagent for V(III), produced on reduction of V(V) with sodium dithionite in dil acetic acid medium. The colored complex is extractable into benzene. The interfering effect of a large number of elements is eliminated completely leading directly to the determination of the metal ion present in traces in samples. The method is applicable to the analysis of different technical samples and the results obtained are highly reproducible. Metal to ligand ratio in the extracted species is determined as 1 : 3.
  • Takashi Sumiyoshi, Meiseki Katayama
    1992 Volume 65 Issue 4 Pages 1038-1040
    Published: 1992
    Released: July 14, 2006
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    The reactivities of the transient UV-band with a peak at 330 nm produced in irradiated liquid carbon tetrachloride with various alcohols have been measured using the absolute technique of pulse radiolysis. The obtained bimolecular rate constants have been compared with those previously determined for the reaction of chlorine atoms with various alcohols using the competitive scavenging method. The values of reaction rate constants of the UV-band are nearly twice those of chlorine atoms. Similar kinetic isotope effects were observed for deuterated methanol and 2-methyl-2-propanol. However, the dependence on the structure of the alcohols, which is characteristic for hydrogen abstraction from alcohols by chlorine atoms, has not been established by the reaction of the UV-band. These results strongly suggest that the assignment of the UV-band to chlorine atoms is not plausible, and instead, support the assignment to parent cations.
  • Junzo Sunamoto, Kazunari Akiyoshi, Tetsuji Kihara, Masayuki Endo
    1992 Volume 65 Issue 4 Pages 1041-1046
    Published: 1992
    Released: July 14, 2006
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    A water-soluble spin probe, disodium 4-[(4,8-sulfonatooxy-2-naphthyl)thioureylene]-2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO-T) was newly synthesized and characterized comparing with several different TEMPO derivatives from the view point of a possibility of utilization in the liposomal studies. Of TEMPO derivatives studied, TEMPO-T was the best probe because of the high water solubility, the less lipophilicity, the less leakiness from liposome, and the reliable stability to both temperature and pH changes.
  • Takeo Akiyama, Yoshihiro Watanabe, Akiko Miyasaka, Toru Komai, Hirobum ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1047-1051
    Published: 1992
    Released: July 14, 2006
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    The title complexes, [Co(cp)(S2C2Y2)](cp = η5-C5H5) (1) (a: Y = Ph, b: Y = 2-pyridyl, c: Y = 4-pyridyl, d: Y = −CO2Me, e: Y = −CN), [Co(cp)(S2C6H4)] (2), [Co(cp)(Se2C2Ph2)] (3), and [Co(cp)(SeSC2Ph2)] (4), are photochemically reduced to give one-electron reduced species, Co(II) complexes, under UV-irradiation in the presence of an electron donor, triethanolamine (TEOA), in acetonitrile solutions. The photoreduction is wavelength dependent. The 313 nm light is the most effective (Φ = 0.002–0.018) for all the complexes used, and the light of wavelength longer than 365 nm is ineffective for the photoreduction of 14. The irradiation with 254 nm light brings about decomposition of the complexes.
  • Kazuyasu Sakaguchi, Tommaso Costa, Hiroshi Sakamoto, Yasuyuki Shimohig ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1052-1056
    Published: 1992
    Released: July 14, 2006
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    A series of phenylalanine homologs with elongated phenylalkyl side chains (R = –(CH2)n-C6H5, n = 1–4) have been incorporated into opioid peptide morphiceptin at position 4 in order to elucidate a role of the amino acid residue in the molecular mechanism of receptor activation. The receptor specificity and selectivity of peptides synthesized were examined in the radio-ligand receptor binding assays using tritiated DAGO- and DADLE-enkephalins. [Phe4]Morphiceptin was most potent for the μ receptors and showed the most pronounced μ/δ-receptor selectivity with a specific ratio of 410. Its μ-affinity was about three times stronger than morphiceptin. All analogs showed very similar CD spectra, suggesting that these peptides have a similar backbone conformation. The results strongly suggest that, besides the backbone conformation, the side-chain aromatic rings at positions 1 (Tyr), 3 (Phe), and 4 (Phe) array in a specific stereoorientation and this array is important to activate μ-receptors. Analogs with longer phenylalkyl side chains appeared not to retain such an arrangement due to the steric hindrance caused by the presence of more than two methylene groups.
  • Isamu Ono, Shoichi Kondo
    1992 Volume 65 Issue 4 Pages 1057-1061
    Published: 1992
    Released: July 14, 2006
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    A molecular dynamics simulation using the atom–atom potential was applied to THE5 of a disk-like mesogenic molecule. The calculations were carried out in a canonical (NVT) ensemble. The results show that the time-averaged molecular properties and molecular ordering are in agreement with experiment. The effects of molecular flexibility in side chains are clearly demonstrated in the profile of the order parameters of each C–H bond.
  • Il-Ryon Jeon, Naoki Noma, Yasuhiko Shirota
    1992 Volume 65 Issue 4 Pages 1062-1066
    Published: 1992
    Released: July 14, 2006
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    A rechargeable battery using electrochemically-doped poly(3-vinylperylene) as a cathode and lithium as an anode was fabricated, and its performance characteristics were examined. The battery exhibits a flat discharge cell voltage at current densities up to 0.8 mA cm−2 with high coulombic efficiency and good cyclability.
  • Yoshiharu Yoneyama, Hiroaki Nakayama, Hiroshi Nishi, Tsutomu Kato
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1067-1071
    Published: 1992
    Released: July 14, 2006
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    Several coals were treated with Cd and butyl iodide at 130 °C under atmospheric pressure to obtain more detailed information concerning coal-solubilization for a metal–alkyl halide system under mild conditions. The treatment effectively converted coal to benzene-soluble products with an optimum yield of 57 wt%, somewhat less than that obtained in a Zn–butyl iodide system. There was no correlation between the rank of coal used and the benzene solubility. Reactions of model compounds were also carried out under similar conditions. Polynuclear aromatic compounds gave polybutyl-substituted and/or -addition derivatives. Although the alkyl ether linkages were easily cleaved, the aryl ether linkages were not. In addition, many butyl groups were introduced into both the aromatic and aliphatic moieties. These results suggest that the high benzene solubility is attained by an introduction of the many butyl groups, as well as cleavage of the alkyl ether linkages. Also, the introduction of butyl groups into the aliphatic moiety suggests smaller benzene solubilities of Cd-treated coal compared to those of Zn-treated coal. Because most of the products of the model compounds were similar to those obtained in the Zn–butyl iodide system, and some of the butyl groups introduced were rearranged to s-butyl, it is suggested that both alkyl cation reactions and alkyl radical reactions occur competitively in the Cd–butyl iodide system, as well as in the Zn–butyl iodide system.
  • Ram Nagina Pandey, Kondapaneni S. Chandra Babu, Dharam Singh, Onkar Na ...
    1992 Volume 65 Issue 4 Pages 1072-1077
    Published: 1992
    Released: July 14, 2006
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    A new type of photoelectrochemical (PEC) solar cell based on semiconductor septum (SC-SEP) photoelectrode has been shown to yield higher electrical power output than the conventional PEC solar cell. In the present study, photoelectrochemical, structural and compositional characteristics of the semiconductor component in n-CdSe/Ti septum, based SC-SEP, PEC solar cell, employing some reversible electrolyte systems under prolonged PEC operation (100 h), revealed that the CdSe photoelectrode undergoes deterioration through ‘Cd’ loss. For example, in the case of the cell Pt, 1 M 3S//n-CdSe/Ti//0.1 M AgNO3 (1 M = 1 mol dm−3), Pt; CdSe showed loss of ‘Cd’. This resulted in decrease of the cell power output (from Vph and Isc of 1.42 V and 20 mA cm−2 to 1.3 V and 13 mA cm−2 respectively). It has been shown in the present investigation that the best way to arrest semiconductor deterioration was by adding 0.1 M Se to polysulfide electrolyte thereby stabilizing this efficient SC-SEP, PEC cell.
  • Ichimin Shirotani, Kazunaga Suzuki, Toshihiro Suzuki, Takehiko Yagi, M ...
    1992 Volume 65 Issue 4 Pages 1078-1083
    Published: 1992
    Released: July 14, 2006
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    The absorption spectra of [Ni(dmg)2], [Ni(niox)2], [Ni(dpg)2], and [Ni(bqd)2] were studied at various pressures. Two characteristic absorption bands, the metal-to-ligand charge-transfer (M–L) and the 3d–4p bands, were observed in the visible region for these complexes. The interesting spectral features observed under high pressures were: (1) The excitations shift remarkably to lower energies with increasing pressure. (2) The rates of the peak shifts for the d–p and M–L bands increase in the order [Ni(niox)2] < [Ni(dmg)2] < [Ni(dpg)2]. (3) The peak shifts of the M–L bands are much smaller than those of the d–p bands. (4) The absorption intensity of the M–L band of [Ni(niox)2] decreases rapidly above 10 GPa, and the band is hardly observed at around 14 GPa. (5) A new absorption band in [Ni(dpg)2] exists above about 3 GPa. The electrical resistivity of [Ni(dmg)2], [Ni(niox)2], and [Ni(dpg)2] has been studied under high pressures. These complexes are insulators with a resistivity of 1015 Ω cm at atmospheric pressure. The resistivities at around 23 GPa were 50 Ω cm for [Ni(dmg)2], 7 × 105 Ω cm for [Ni(niox)2] and 2 × 103 Ω cm for [Ni(dpg)2].
  • Tadashi Suzuki, Yoshizumi Kajii, Kazuhiko Shibuya, Kinichi Obi
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1084-1088
    Published: 1992
    Released: July 14, 2006
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    The time-resolved thermal lensing (TRTL) technique was employed to study the photocyclization of diphenylamine (DPA) to form intermediate 4a,4b-dihydrocarbazole (DHC) in methanol solution at room temperature. The heat of reaction, ΔH, was determined to be (2.6 ± 0.2) × 102 kJ mol−1 (1DPA → 1DHC): The reaction proceeds endothermically. The ring closure step proceeds on the triplet surface (3DPA*3DHC*). These triplet states are found to be isoenergetic by analyzing the time evolution of the TRTL signal. 3DHC* is located at 21 kJ mol−1 above 1DHC. Furthermore, two-color laser flash photolysis experiments have revealed that the photoexcitation of intermediate 1DHC leads to the recovery of parent DPA and therefore inhibits the formation of carbazole.
  • Robin Kumar Dutta, Subray Narayan Bhat
    1992 Volume 65 Issue 4 Pages 1089-1095
    Published: 1992
    Released: July 14, 2006
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    Interactions of cationic dyes, viz., phenosafranine (PSF), safranine O (SFO) and safranine T (SFT) with anionic surfactants, viz., sodium dodecyl sulfate (SDS) and sodium octyl sulfate (SOS) in submicellar concentration ranges have been investigated spectroscopically. The interaction has been shown to be an induced protonation of the dye in the dye–surfactant ion pair. Even though the opposite charges on the dye and the surfactant are the primary requirements for the ion pair formation, it is the hydrophobicity of the surfactant as well as of the dye which induces the protonation. The spectroscopic and thermodynamic parameters show that the orders of effectiveness of the dyes and the surfactants for the interaction are, SFO > SFT > PSF and SDS >> SOS.
  • Rajagopal Gurumurthy, Kulathu Iyer Sathiyanarayanan, Mannathusamy Gopa ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1096-1100
    Published: 1992
    Released: July 14, 2006
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    The kinetics of oxidation of several substituted ethyl phenylthioacetates by bromamine-B (sodium salt of N-bromobenzenesulfonamide) has been studied in 50% (v/v) aqueous ethanol medium. Disodium hydrogenphosphate and sodium dihydrogenphosphate buffer has been used. The reaction is of a total second order, first order each with respect to the reactants. A catalytic effect of mercury has been observed and the order with respect to Hg(II) is one. Electron-releasing substituents generally accelerate the rate while electron-withdrawing groups retard the rate. A good correlation is found to exist between log k2 and Hammett σ constants. Two mechanisms have been proposed, one in presence of Hg(II) and the other in the absence of Hg(II). In presence of Hg(II), rate = k[C1][H2OBr]+ and in the absence of Hg(II), rate = k[S] [H2OBr]+

    Susceptibility of the reaction to the steric effect of ortho substituents, has been analyzed in the light of application of Taft’s steric energy relationships.
  • Saroja Viraraghavan
    1992 Volume 65 Issue 4 Pages 1101-1108
    Published: 1992
    Released: July 14, 2006
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    The effects of ascorbate, the interference of the Jaffé reaction was individually studied by polarography, spectrophotometry, and thin-layer chromatography. Ascorbate was incubated in 28.4 mmol dm−3 picrate blank solution in 0.51 mol dm−3 NaOH at 25.00 ± 0.02 °C and the reactivity of test solution containing ascorbate : picrate was investigated. Picramic acid formed in all ascorbate: 28.4 mmol dm−3 picrate test solutions which explained the observed positive interference of ascorbic acid. No fluorescent product was formed in ascorbate : picrate test solutions. The reactivity of ascorbate : picrate test solutions confirmed that ascorbate was a powerful reducing agent. 2-Furaldehyde which has been listed as one of the degradation products of ascorbic acid, is not identified under the experimental conditions.
  • Hiroshi Hamana, Fuminori Iwasaki, Hiroyoshi Nagashima, Kazuhisa Hattor ...
    1992 Volume 65 Issue 4 Pages 1109-1113
    Published: 1992
    Released: July 14, 2006
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    The lithium alkylamide-catalyzed addition reaction of p-substituted benzylamines with m- and p-divinylbenzene was examined in order to synthesize new styrene derivatives. Though divinylbenzene possesses two vinyl groups, 1 : 1 adducts, the N-(p-substituted benzyl)vinylphenethylamines (6, 8) were found to be prepared selectively. The reaction with styrene was also examined as a model reaction. From kinetic studies, the Hammett p values for the addition reaction of p-substituted benzylamines to the styrene, m-divinylbenzene and p-divinylbenzene, were −0.72, −0.67, and −1.1, respectively, at 50 °C.
  • Xian-Yong Wei, Eisuke Ogata, Etsuo Niki
    1992 Volume 65 Issue 4 Pages 1114-1119
    Published: 1992
    Released: July 14, 2006
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    Hydrocracking reactions of α,ω-diarylalkanes (DAAs) were carried out in the presence of FeS2 catalyst to examine the structural effect of DAAs on the reactivities of DAAs toward hydrocracking. Reactivities and reaction pathways of DAAs were found to depend not only on aromatic ring size, but also on the number of methylene between aromatic rings. Diarylmethanes were hydrocracked via Car–Calk bond scission, while the Car–Calk bond scission for 1,2-diarylethanes and 1,3-diarylpropanes seemed to be very difficult. These results could be interpreted by the hydrogen-accepting abilities of the ipso-carbons in the substrates and the resonance stabilities of the resulting arylalkyl radicals.
  • Satoshi Kubo, Yoshihiro Mimaki, Yutaka Sashida, Tamotsu Nikaido, Taich ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1120-1124
    Published: 1992
    Released: July 14, 2006
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    Four new cholestane bisdesmosides have been isolated from the fresh bulbs of Ornithogalum thyrsoides. Their structures were determined by spectroscopic analysis and chemical evidence to be (22S)-5α-cholestane-1β,3β,16β,22-tetrol 1-O-α-L-rhamnopyranoside 16-O-β-D-glucopyranoside (1), (22S)-5α-cholestane-1β,3β,16β,22-tetrol 1-O-α-L-rhamnopyranoside 16-O-(6-O-acetyl-β-D-glucopyranoside) (2), (22S)-5α-cholest-24-ene-1β,3β,16β,22-tetrol 1-O-α-L-rhamnopyranoside 16-O-β-D-glucopyranoside (3), and (22S)-5α-cholest-24-ene-1β,3β,16β,22-tetrol 1-O-α-L-rhamnopyranoside 16-O-(6-O-acetyl-β-D-glucopyranoside) (4), respectively. An advanced Mosher’s method was applied to determine the C-22 absolute configuration. Compound 4 showed inhibitory activity on cyclic AMP phosphodiesterase.
  • Nidhi Sharma, Som Kant Mishra, Prem Dutt Sharma
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1125-1130
    Published: 1992
    Released: July 14, 2006
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    The kinetics of oxidation of uric acid (UaH2) by chloramine-T (CAT) studied in the presence of osmium(VIII) in alkaline medium conform to a rate law (i)

    where K2 and K3 are second dissociation constant of uric acid and formation constant of an intermediate complex respectively. Osmium(VIII) catalyzes the reaction intramolecularly via redox cycle of Os(VIII)/Os(VI).
  • Habib Firouzabadi, Iraj Mohammadpour-Baltork
    1992 Volume 65 Issue 4 Pages 1131-1134
    Published: 1992
    Released: July 14, 2006
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    Zinc bismuthate is an easily prepared and a stable compound. It could be used as an oxidant in organic solvents under aprotic or in the presence of a catalytic amount of a protic solvent. Primary and secondary saturated, allylic, and benzylic alcohols are converted to their carbonyl compounds in high yields. Mildness of the reagent is shown by the oxidation of thiols to their disulfides in excellent yields. Thioethers are also oxidized to their corresponding sulfoxides in good yields.
  • Koji Saito, Akihiro Yoshino, Tadayoshi Yoshida, Kensuke Takahashi
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1135-1137
    Published: 1992
    Released: July 14, 2006
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    The 1H and 31P NMR spectra of the title compounds dissolved in a nematic phase of N-(p-ethoxybenzylidene)-p-butylaniline (EBBA) were analyzed, and the structures of the proton and phosphorus skeleton determined.
  • Takashi Yamane, Tamaichi Ashida, Kazuhiko Hashimoto, Hiroshi Sumitomo
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1138-1140
    Published: 1992
    Released: July 14, 2006
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    The crystal structure of the title compound has been determined in order to study the structure-reactivity relationship of a bicyclo compound. C15H15O3, M 257.29, monoclinic, space group P21/a, a = 24.122(6), b = 6.990(2), c = 7.800(2) Å, β = 94.27(2)°, V = 1311.5(6) Å3, Z = 4, Dx = 1.304 g cm−3, μ = 7.56 cm−1 for Kα. The final R-value is 0.062 for 1948 reflections. The molecular structure is essentially the same as that of the N-benzoyl derivative of the bicyclo compound. An elongation of the C–N bond distance in the lactam-amide moiety, which had been found in the N-benzoyl derivative, was observed and compared with that in the unmodified bicyclo compound. There seems to be little extension of the conjugation of the olefinic group to the carbonyl or phenyl groups in a cinnamoyl moiety, according to the C=C and Csp2–Csp2 distances.
  • Masahiko Arai, Satoshi Hamada, Yoshiyuki Nishiyama
    1992 Volume 65 Issue 4 Pages 1141-1143
    Published: 1992
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    A glass substrate was modified by thermal and chemical treatments with a fluoride solution and molten potassium salt. These surface treatments were found to affect both the electroconductive and optical properties of tin oxide film prepared by plasma-assisted chemical vapor deposition.
  • Kazuhisa Murata, Hirobumi Ushijima, Hisashi Ueda, Kenji Kawaguchi
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1144-1145
    Published: 1992
    Released: July 14, 2006
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    The magnetic properties of pyro-carbons prepared from poly(vinyl chloride) and activated carbon were examined. In contrast with the observation of a hysteresis from vibrating sample magnetometer measurement, the ESR spectra showed only an usual Δms = ±1 signal. The temperature dependence of the magnetic susceptibility approximately obeys Curie’s law: The estimated spin density is ca. 1019 spins/g, roughly close to that calculated from ESR method. Therefore, it seems likely that the bulk magnetic nature of PVC/C sample is still paramagnetic, although there is a possibility that local microregions having anomalous high spin character could be formed in the sample.
  • Iwao Satake, Koichiro Uchino, Katumitu Hayakawa, Tamaki Maeda
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1146-1148
    Published: 1992
    Released: July 14, 2006
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    The study was made of the binding isotherms of decyl sulfate ion to poly(L-ornithine) with 1-alkanesulfonate counter ions of the chain length (n) from 3 to 7. The coil to helix transitions of polypeptide chain in these syctems were also studied. Although the binding cooperativity decreased rapidly with increasing n, the conformational change was insensitive to n.
  • Takahide Kimura, Mitsue Fujita, Hajime Sohmiya, Takashi Ando
    1992 Volume 65 Issue 4 Pages 1149-1150
    Published: 1992
    Released: July 14, 2006
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    The selectivities in the competitive dehydrogenation of alcohols, such as benzhydrol and cinnamyl alcohol, with active manganese dioxide under catalytic conditions are different from those under the usual conditions.
  • Teruo Kurihara, Sumio Ishikawa, Tetsuo Nozoe
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1151-1153
    Published: 1992
    Released: July 14, 2006
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    An examination was made of the stability and formation pathways of azulenequinones produced by oxygenation in terms of Aihara’s graph theory of aromaticity and Gimarc’s TCS rule. In view of the TCS rule, the oxygen molecule in autoxidation first attacks C-1 of the azulenes, followed by the another oxygen molecule attacking at position n in 1-carbonylated azulenes to give azulenequinones.
  • Tadashi Hanaya, Hiroshi Yamamoto, Hiroshi Yamamoto
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1154-1156
    Published: 1992
    Released: July 14, 2006
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    The addition of dimethyl phosphonate to six 5,6-dideoxy-6-nitro-D-hex-5-enofuranoses at 25 °C in the presence of triethylamine preponderantly gave (5R)-adducts, whereas the same reaction at 100 °C without a base yielded (5S)-adducts as the main products.
  • Hiroshi Yamataka, Kazuhiko Yamaguchi, Tsutomu Takatsuka, Terukiyo Hana ...
    1992 Volume 65 Issue 4 Pages 1157-1158
    Published: 1992
    Released: July 14, 2006
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    The reactions of o-, m-, or p-bromobenzophenone and o-iodobenzophenone with various Grignard reagents were carried out in diethyl ether at 0 °C. The product analysis showed that these halobenzophenones can be a good chemical probe to evaluate the electron-transfer ability of nucleophiles to the aromatic ketones.
  • Yozo Miura, Fumihiko Yamaguchi, Yoshiaki Ogo
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1159-1161
    Published: 1992
    Released: July 14, 2006
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    4-(4-Hydroxy-5-isopropyl-2-methylphenyl)-6-isopropyl-3-methyl-3,5-cyclohexadiene-1,2-dione and 5,5′-diisopropyl-2,2′-dimethyl-3,4,4′-biphenyltriol, isolated from thyme, and their analogues, 4-(2,5-dimethyl-4-hydroxyphenyl)-3,6-dimethyl-3,5-cyclohexadiene-1,2-dione and 2,2′,5,5′-tetramethylbiphenyl-3,4,4′-triol, have been synthesized and their deodorant activities against methanethiol measured.
  • Masatomi Sakamoto, Masayuki Hashimura, Yusaku Nakayama, Akira Matsumot ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1162-1164
    Published: 1992
    Released: July 14, 2006
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    Fluorescent spectra of the mononuclear europium(III) complex, Eu(H2 fsaen) (NO3)·5H2O, and the heteronuclear complexes MEu(fsaen) (NO3nH2O (n = 4 for M = Cu(II) and n = 6 for M = Ni(II)), were compared, where H4 fsaen is a binucleating ligand, N,N′-bis (3-carboxysalicylidene)ethylenediamine. It was found that the fluorescent bands of Eu(III) observed for the mononuclear complex were significantly quenched on forming binuclear complexes.
  • Taketoshi Nakahara, Tamotsu Wasa
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1165-1167
    Published: 1992
    Released: July 14, 2006
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    In order to enhance the sensitivity of mercury, the most effective reductant, tin(II) chloride was added to a mercury solution, and the mixture was immediately introduced into the plasma through a conventional pneumatic nebulizer. The attainable detection limit for mercury was inproved from 79 ng ml−1 in the untreated solutions to 1.3 ng ml−1 when tin(II) chloride was added. The present method was successfully applied to the determination of trace concentrations of mercury in several samples of waste water.
  • Tadao Harada, Tsutomu Osawa
    1992 Volume 65 Issue 4 Pages 1168-1169
    Published: 1992
    Released: July 14, 2006
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    Disodium maleate was converted to a mixture of disodium maleate, fumarate, and succinate in the solid phase when particles of the starting material were kept in contact with fine nickel powder pretreated with hydrogen gas at 200 °C.
  • Moni Mohan Bhattacharyya
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 4 Pages 1170-1172
    Published: 1992
    Released: July 14, 2006
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    New estimates of ionic viscousity B-coefficient and NMR B′-coefficient have been obtained in aqueous solutions over the temperature range 0 to 95 °C by a recently developed method. The derived values for the alkali metal and halide ions have been compared with the existing ones and the discrepancies discussed. Temperature effect on the two coefficients for the simple inorganic ions has been satisfactorily discussed using the concept of the Frank and Wen model. Energy of activation for viscous flow has also been calculated using the Eyring model and three different values are obtained for each ion over the temperature range studied.
  • Kazuhiko Ozutsumi, Shin-ichi Ishiguro
    1992 Volume 65 Issue 4 Pages 1173-1175
    Published: 1992
    Released: July 14, 2006
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    The complexation of 1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown-6) with sodium, potassium, rubidium, caesium, and ammonium ions has been studied by precise titration calorimetry in aqueous solution containing 0.1 mol dm−3 (C2H5)4NCl as a constant ionic medium at 25 °C. The calorimetric data were well explained in terms of the formation of the [M(18-crown-6)]+ (M = Na+, K+, Rb+, Cs+, and NH4+) complexes, and their formation constants, enthalpies, and entropies were determined. The thermodynamic parameters of the complexes thus obtained are discussed in relation to their structures in solution.
  • Ken-ichiro Motoda, Hiroshi Sakiyama, Naohide Matsumoto, Hisashi Okawa, ...
    1992 Volume 65 Issue 4 Pages 1176-1178
    Published: 1992
    Released: July 14, 2006
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    The reaction of 2,6-difomyl-4-methylphenol and 1,9-diamino-3,7-diazanonane in methanol in the presence of lead(II) ion forms a dinuclear lead(II) complex of a very rare macrocycle containing hexahydropyrimidine rings. The structure of the complex is determined by single crystal X-ray method.
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