Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 60 , Issue 5
Showing 1-50 articles out of 64 articles from the selected issue
  • Zen-ichiro Takehara, Kiyoshi Kanamura
    1987 Volume 60 Issue 5 Pages 1567-1572
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The interface between PbO2 and PbSO4 was considered to be the reaction site of the oxidation of PbSO4 to PbO2. The area of this site depended on the changing crystal size of PbSO4 with the discharge conditions. The oxidation rate of PbSO4 to PbO2 increased with a decrease in the crystal size of PbSO4 since the reaction site area per unit volume increased with a decrease in the crystal size of PbSO4. The oxidation of PbSO4 to PbO2 depended on the discharge current, the sulfuric acid concentration and the rest time after a discharge.
  • Yoshiharu Usui, Hiroaki Misawa, Hirochika Sakuragi, Katsumi Tokumaru
    1987 Volume 60 Issue 5 Pages 1573-1578
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Sensitized reduction of methyl viologen, MV2+, occurs efficiently through electron transfer from triplet xanthene dyes to MV2+ followed by electron transfer to the resulting semioxidized dyes from a reductant like triethanolamine. Unreactive ion pair complexes between these dyes and MV2+ are formed (formation constant: 1.2×103 M−1 for Eosine Y and MV2+ in 50% aqueous ethanol solution). The quantum yield for the reduced methyl viologen radical depends on the concentrations of MV2+ and the amine and on the ionic strength of solution. The efficiency of the electron transfer from triplet dyes to MV2+ is increased by addition of alcohol, and solvent effects on the reaction mechanism are discussed.
  • Kazuo Sugiyama, Hiroshi Miura, Yoshichika Watanabe, Yasunori Ukai, Tsu ...
    1987 Volume 60 Issue 5 Pages 1579-1583
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The liquid-phase hydration of acrylonitrile to acrylamide has been examined over various metal catalysts at 75 °C. Five metal elements-Cu, Ag, Fe, Co, and Ni-showed the catalytic conversion of acrylonitrile. The Cu and Ag catalysts gave the acrylamide with a 100% selectivity, while the other metals, Fe, Co, and Ni, yielded three products: acrylamide, ethylene cyanohydrin, and bis(2-cyanoethyl) ether. The alloying of Cu and Ni led to an increase in the formation of acrylamide with keeping the high selectivity to acrylamide. Especially, Cu–Ni alloys, with a range of 20–70% Cu in their bulk composition, were much more active catalysts than Cu. The maximum yield of acrylamide was obtained on the Cu–Ni alloy catalysts was observed, although such a retardation occurred on the Cu catalyst surface. The maximum synergistic effect was observed over the alloy with the surface component ratio of Cu to Ni of 4; this effect was discussed.
  • Haruo Nakayama, Kiyoshi Tsunakawa, Mizue Kan\={o}, Hiroshi Matsui
    1987 Volume 60 Issue 5 Pages 1585-1588
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The amount of either methyl or ethyl alcohol intercalated within clathrate-like hydrates of tetrabutylammonium fluoride and of tetrabutylammonium propionate has been determined using 14C-labeled alcohols. It was found that (1) methyl alcohol could be intercalated within the tetrabutylammonium fluoride hydrate but not within the tetrabutylammonium propionate hydrate; (2) ethyl alcohol could be intercalated within both the tetrabutylammonium fluoride and tetrabutylammonium propionate hydrates; and (3) the amount of the alcohol intercalated increased with increasing concentration of alcohol in the initial solutions. These results were interpreted by taking into consideration the states of vacant pentagonal dodecahedra formed by hydrogen-bonded water networks.
  • Hiroyoshi Kanai, Shigeyoshi Sakaki, Takenobu Sakatani
    1987 Volume 60 Issue 5 Pages 1589-1594
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The stoichiometric or a little excess amount of NaBH4 was treated with [MX2(PR3)2] (M=Co, Ni, X= halides, SCN, PR3=PPhnEt3−n) in THF–1,2-dimethoxyethane to form monohydride species which were active for isomerization of 1-butene. The reaction was accelerated by excess PPh3 in [CoX2(PPh3)2]–NaBH4 systems. Other catalytic systems have optimum ratios of excess phosphine to metal for getting maximum activities. Thiocyanate–metal complexes are the most active in each Co– and Ni–catalyst system. Cisselectivity depends on the cone angle of PR3, the size of anion ligands, and the congested structure of complexes.
  • Jiro Tanaka, Yasuyoshi Saito, Masaaki Shimizu, Chizuko Tanaka, Masashi ...
    1987 Volume 60 Issue 5 Pages 1595-1605
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Raman spectra of alkaline metal doped polyacetylene were studied at various levels of doping for (CHMy)x, and (CDMy)x, M=Na and K, with y=0–0.18. Several steps in the doping process can be recognized in changes of the Raman spectra; the initial Raman lines remain for y=0–0.06 but change completely into a new pattern at y=0.13. Raman and ESR spectra of alkaline metal doped β-carotene were measured as a model study of the alkaline metal doping of polyacetylene. The correlation of these spectra together with the ab initio SCF MO calculation on model compounds show that a heavily alkaline metal doped polyacetylene chain does not have a uniform bond length structure but is composed of a charged soliton structure connected by a uniform chain. The new Raman bands were assigned based on this structure, implying that a bond alternation still exists in the metallic state of alkaline doped polyacetylene.
  • Michiko Takamoto, Seiji Ogihara, Kiyoshi Yase, Masakazu Okada
    1987 Volume 60 Issue 5 Pages 1607-1611
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Esters of octadecanoic acid and three primary alcohols such as methanol, ethanol, and propanol were deposited on substrates of potassium chloride (KCl), mica and amorphous carbon film under vacuum. The surface morphology of their films was observed by transmission electron microscope. They grew epitaxially to form the rectangular crystals with lateral molecular orientations on KCl substrate. On the other hand, ester molecules tend to arrange normal to the surface of mica and amorphous carbon film and construct the molecular layers like to Langmuir-Blodgett films. The crystal axis relationship between esters and KCl(001) surface was followed; c-axisester is parallel to ⟨110⟩KCl direction and ⟨110⟩ester direction inclines with an angle of about ±16° corresponding to ⟨110⟩KCl. These molecules had resemble crystal structures with trans configuration in the ester moiety. The optimum temperatures of substrates in the former epitaxial growth exist and the temperature decreases in proportion to the chain length of alcohol group with the discrepancy of about 10 to 30 °C.
  • Hideo Kimizuka, Hirohiko Waki, Akira Matsubara, Y\={o}ichi Arimoto
    1987 Volume 60 Issue 5 Pages 1613-1615
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The ion-exchange resin–electrolyte solution equilibria were studied on the basis of thermodynamics. The experimental results showed that the external salt activity divided by the co-ion concentration in the ion-exchange resins was linear against the co-ion concentration in the resin. The equilibria were consistently explained by a partition coefficient of salt distribution with the additivity law for the counter ions in the ion-exchange resin. A thermodynamic expression for the ion-exchange reaction was also discussed.
  • Masayuki Taniguchi, Toshiharu Yoshioka, Hiroshi Yoshida
    1987 Volume 60 Issue 5 Pages 1617-1623
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    In order to experimentally elucidate the chemical reactions of methanol combustion, the concentration profiles of ten chemical species were determined in stoichiometric CH3OH–O2–Ar flat flame at low pressure, 1.11×104 Pa. The concentrations of three labile intermediates (H, O, and OH) as well as that of stable O2 molecules, were measured by means of the probe-sampling-ESR method. The concentrations of six stable species (CH3OH, CH2O, CO, CO2, H2, and H2O) were measured using a quadrupole mass spectrometer. The rates of the net chemical formation (or decay) of these species were determined by subtracting the effect of diffusion from their observed concentration profiles, and were examined on the basis of the reaction mechanisms previously proposed for methanol combustion. The experimental results were found to be consistent with the oxidation pathway CH3OH→CH2OH→CH2O→CHO→CO→CO2. The results also showed that the reaction CH2OH+O2→CH2O+HO2 is an important pathway for O2 consumption.
  • Hiroshi Sakai, Yutaka Maeda
    1987 Volume 60 Issue 5 Pages 1625-1629
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The 129I Mössbauer effect has been applied to investigate 2:3 molecular complexes of triphenylphosphine sulfide–iodine and acridine–iodine. The Mössbauer spectra indicate the presence of three unequivalent iodine sites (IA, IB, and IC), as expected from the crystallographic data of these complexes. The iodine atom (IA) coordinating to the sulfur or nitrogen atom of each donor molecule is more positively charged than that of the 1:1 molecular complex containing the same donor atom. This result can be interpreted in terms of the covalency of the S···IA or N···IA bond. The degrees of charge transfer in the 2:3 complexes are close to those in the 1:1 complexes, and the transferred charges are mainly localized on the terminal iodine atoms (IB). The iodine molecule (IC) cross-linked to two IB atoms has a slightly negative charge, consistent with the bond distance of the molecule. The iodine moieties of these complexes are very similar to the structure of I82− in Cs2I8.
  • Heisaburo Shindo, Yukio Hiyama, Siddhartha Roy, Jack S. Cohen, Dennis ...
    1987 Volume 60 Issue 5 Pages 1631-1640
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Solid-state 2H NMR spectra were measured as a function of relative humidity for nonoriented DNA films and oriented DNA fibers deuterated at C8 carbons of the purine bases. The line-shape analyses of the quadrupole echo spectra from oriented DNA fibers demonstrated that the purine base planes of the A form of DNA were tilted by about 70° relative to the helix axis, and that base planes of the B form varied significantly, although they were, on average, perpendicular to the helix axis. These results were generally consistent with the X-ray fiber diffraction studies and the single crystal structures of oligonucleotides. Analyses of 2H relaxation times, T1 and T2, showed at 79% RH that the orientation of the base planes fluctuated about an axis normal to the helix axis with a correlation time, τc=3.6×10−8 s and amplitude of 8.5°. The correlation time of the base plane fluctuation was 1.5×10−8 s and the amplitude was 13.5° at 92% RH. In addition, at 92% RH, but not at 79% RH, the base planes reoriented slowly, τc ≈10−6 s, about the helix axis, through an rms angle of ca. 30°.
  • Hironobu Umemoto, Teruo Uchida, Shigeru Tsunashima, Shin Sato
    1987 Volume 60 Issue 5 Pages 1641-1643
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The bimolecular rate constants for the reactions of ground state atomic nitrogen with hydrogen halides and deuterium iodide were measured by employing a pulse radiolysis-resonance absorption technique. As for the reactions of hydrogen iodide and deuterium iodide, the temperature dependence was also measured; it was found that the rate constants were well expressed by the following Arrhenius expressions: k(N+HI)=(3.6±0.6)×105 exp[−(1530±50)⁄T]; k(N+DI)=(1.0±0.4)×105 exp[−(1460±130)⁄T], in units of m3 mol−1 s−1. The preexponential factors for these reactions are much smaller than the semiempirically calculated ones. These small preexponential factors suggest that these reactions proceed non-adiabatically. The rate constants for hydrogen bromide and hydrogen chloride were found to be very small.
  • Akira Yamauchi, Hitoshi Shinohara, Makoto Shinoda, Masashi Date, Yutak ...
    1987 Volume 60 Issue 5 Pages 1645-1648
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    A conductance matrix describing the ion-transport phenomena in the membrane-three ion system has been determined. It was indicated there that six independent experiments were required in order to determine six independent elements of the conductance matrix. The NaCl–CaCl2–amphoteric membrane system was chosen as the three ion system, and three kinds of fluxes, two kinds of transport numbers, and the membrane conductance were measured. Nine elements were experimentally determined on the assumption of Onsager’s reciprocal relation. The results showed that the order of elements in conductance matrix was gCaCa>gClCl>gNaNa>gCaCl>gNaCl>gCaNa. In addition, it was pointed out that the interactions among ions can never be ignored when the ion-transport phenomena across membrane are studied.
  • T. Ken Miyamoto, Shigeru Takagi, Tai Hasegawa, Seizi Tsuzuki, Eitaro T ...
    1987 Volume 60 Issue 5 Pages 1649-1659
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The synthesis and properties of new, bulky atropisomeric porphyrins are described. Four atropisomers of 5,10,15,20-tetrakis(3,5-di-t-butyl-2-nitrophenyl)porphyrins has been easily separated and purified by column chromatography. The isomers all have different thermal stabilities toward atropisomerization. Below 60 °C, however, they have rather high conformational stabilities, and an iron(III) or manganese(III) ion has been incorporated into each isomer, with a retention of the ligand conformation. By the use of these metal complexes, the catalytic oxygenation reactions, i.e., the epoxidation of olefins (styrene, α-methylstyrene, cyclohexene, and cyclooctene) and the hydroxylation of alkanes (cyclohexane and heptane), have been done in the presence of hypochlorite or iodosylbenzene as an oxidant. Products analyses by GLC show that these new complexes effectively catalyze the oxygenations in higher yields or in more selective ways, than the corresponding TPP complexes.
  • Fumihiro Arifuku, Keizo Iwatani, Kikujiro Ujimoto, Hirondo Kurihara
    1987 Volume 60 Issue 5 Pages 1661-1665
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The catalytic electroreduction of an oxygen molecule on a glassy carbon electrode covalently modified with [5,10,15,20-tetrakis(4-carboxyphenyl)porphinato]iron(III) (abbreviated as GC-O-Fe(III)TCPP) was investigated in an aqueous solution. The reduction of oxygen on the GC-O-Fe(III)TCPP electrode occurs at a more anodic potential than on the glassy carbon electrode adsorbing Fe(III)TCPP. This anodic shift of the oxygen reduction potential may be closely related to the number of bonds between a metalloporphyrin molecule and the electrode material. The oxygen molecule is reduced via the one-step reduction accompanying four-electron and four-proton transfer at pH 7–11 and via two successive reductions accompanying two-electron transfer and subsequently two-electron and four-proton transfer at pH>11.5. At pH<6, the number of transferred electron could not be reproducibly determined because of the cleavage of several ester linkages.
  • Fumihiro Arifuku, Rika Nishino, Kikujiro Ujimoto, Hirondo Kurihara
    1987 Volume 60 Issue 5 Pages 1667-1672
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The equilibria among the species of [5-phenyl-10,15,20-tris(4-sulfonatophenyl)porphinato]iron (Fe–TPPS3) ion in aqueous solution and the redox reactions of the central metal were investigated by electrochemical and spectro-electrochemical methods. In the range of pH 3–12.5, the species formed by the reduction of Fe(III)–TPPS3 in solution was identified as the monomeric Fe(II)–TPPS3, while Fe(III)–TPPS3 exists in both monomeric and dimeric species in equilibrium. The monomeric Fe(III)–TPPS3 was demetallated at pH below 3 in the course of reduction of the Fe(III)–TPPS3 solution. The μ-oxo-dimer of Fe(III)–TPPS3 in highly basic solution was reversibly reduced to Fe(II)–TPPS3 and subsequently the monomeric Fe(I)–TPPS3. The formation of the stacking-type dimer of Fe(III)–TPPS3, significantly depending on the concentration of Fe(III)–TPPS3, was presumed to have a pH below 6.
  • Satoru Nakashima, Yuichi Masuda, Izumi Motoyama, Hirotoshi Sano
    1987 Volume 60 Issue 5 Pages 1673-1680
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Iron atoms in the two different crystal forms of 1′,1'″-dibutylbiferrocenium triiodide showed different temperature-depending mixed-valence states; i.e., an averaged-valence state at higher temperatures and a trapped-valence state at lower temperatures in one crystal form but only a trapped-valence state from 78 K to room temperature in the other crystal form. The temperature-depending mixed-valence states were observed in 1′,1'″-diisobutylbiferrocenium triiodide, whereas only a trapped-valence state was found in 1′,1'″-dipentylbiferrocenium triiodide. Both the 1′,1'″-dibutyl- and 1′,1'″-diisobutylbiferrocenium triiodide showed Mössbauer spectra that were different from those of their crystalline states in a dispersed state. A good correlation of the anisotropy of g-values with the mixed-valence states was observed in the ESR spectra for a series of 1′,1'″-dialkyl- and 1′,1'″-bis(methylbenzyl)biferrocenium triiodides. The difference in the ESR parameters between these compounds in the crystalline state was reduced in the dispersed state.
  • Masahiro Mikuriya, Sigeo Kida, Ichiro Murase
    1987 Volume 60 Issue 5 Pages 1681-1689
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The crystal structures of four binuclear copper(II) complexes of N,N′,N″,N'″-tetrakis(2-aminoethyl)-1,4,8,11-tetraazacyclotetradecane (taec), [Cu2(taec)I](ClO4)3(1), [Cu2(taec)F](ClO4)3·H2O (2), [Cu2(taec)(NO2)](ClO4)3(3), and [Cu2(taec)(CH3COO)](ClO4)3·2H2O (4), were determined by single-crystal X-ray analysis. In all the complexes, each copper is coordinated by two ring- and two pendant-nitrogen atoms. All the complexes except for 4 adopt similar structures, where I, F, or NO2 is incorporated into the “cavity” of [Cu2(taec)]4+ as a bridging group. The structure of 4 is different from those of 1, 2, and 3. In 4, one of the oxygen atoms of acetate ion coordinates to one of the copper ions at the apical site and the other oxygen occupies an in-plane coordination site of the other copper ion. The structural effect of incorporation of an anion, X, into [Cu2(taec)]4+ was discussed on the basis of the crystal structures.
  • Shin-ichi Ishiguro, Kazuhiko Ozutsumi, László Nagy, Hito ...
    1987 Volume 60 Issue 5 Pages 1691-1698
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Complexation of copper(II) with Br ions has been studied by calorimetry and spectrophotometry in N,N-dimethylformamide (DMF) containing 0.16 mol dm−3 (C2H5)4NClO4, 1 mol dm−3 LiClO4, and 1 mol dm−3 NH4ClO4 as constant ionic media at 25 °C. Calorimetric titration curves obtained in each solution were well explained in terms of formation of [CuBrn](2−n)+ (n=1–4) and their formation constants, enthalpies and entropies were determined. Electronic spectra of individual copper(II) bromo complexes were also determined in the (C2H5)4NClO4, LiClO4, and NH4ClO4 DMF solutions over the range 260–500 nm, the spectra of each complex being kept practically unchanged in these solutions. The complexation of copper(II) with Br ions is considerably weaker in the LiClO4 solution than in the (C2H5)4NClO4 one and is even more weakened in the NH4ClO4 solution due to the formation of LiBr and NH4Br ion pairs in the relevant solutions. The variation of the stepwise enthalpy and entropy values suggests that the coordination structure around copper(II) ion changes from octahedral to tetrahedral at the formation of [CuBr3]. The result for the complexation between copper(II) and bromide ions thus obtained was compared with that for the complexation between the metal and chloride ions.
  • Masamichi Atoh, Hirofumi Sugiura, Yoji Seki, Kazuo Kashiwabara, Junnos ...
    1987 Volume 60 Issue 5 Pages 1699-1707
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Nine new cobalt(III) complexes containing 3,6-diphenyl-3,6-diphosphaoctane-1,8-diamine (NPPN), trans-[CoCl2(rac(P)-NPPN)]+, cisα-[Co(L)(rac(P)-NPPN)]n+ (L=en, n=3; L=acac, n=2) and Δ- and Λ-cisα-[Co(L′)(rac(P)-NPPN)]n+ (L′=R-pn, n=3; L′=S-ala or S-pro, n=2), and five new cobalt(III) complexes containing (2S,9S)-4,7-diphenyl-4,7-diphosphadecane-2,9-diamine (SS(C)-NPPN), Δ- and Λ-cisα-[Co(L)(rac(P)SS(C)-NPPN)]n+ (L=en, n=3; L=acac, n=2) and Δ-cisβ-[Co(acac)(meso(P),SS(C)-NPPN)]2+, were prepared, where en, R-pn, acac, S-ala and S-pro denote ethylenediamine, (R)-1,2-propanediamine, 2,4-pentanedionate, (S)-alaninate and (S)-prolinate ions, respectively. Stereochemistries of the complexes and the chiral phosphorus donor atoms were studied on the basis of the absorption, 1H and 13C NMR, and CD spectra. The rac(P)-NPPN and rac(P),SS(C)-NPPN ligands formed selectively either the trans or cisα isomer, while no stable complex was obtained with the meso(P) isomers of NPPN and SS(C)-NPPN except cisβ-[Co(acac)(meso(P),SS(C)-NPPN)]2+ which slowly decomposes in water.
  • Ken-ichi Okamoto, Hideki Umehara, Masayo Nomoto, Hisahiko Einaga, Jins ...
    1987 Volume 60 Issue 5 Pages 1709-1714
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Of three possible isomers for the (L-cysteinato)(diethylenetriamine)cobalt(III) complex, [Co(L-cys)(dien)]+, two isomers are selectively prepared. Of the two isomers, the crystal structure of the dominantly formed isomer has been determined by the X-ray diffraction method. The greenish brown needle crystal was orthorhombic, space group P212121, a=16.589(4), b=20.510(9), c=12.479(4) Å, and Z=4. The structure has been refined to R=0.068 on 5913 observed reflections. There are three crystallographically independent complex cations in an asymmetric unit. All the complex cations have trans(NiS) configuration and the L-cysteinate coordinates facially to the cobalt atoms as terdentate-N,O,S ligand. The isomers of the (S-methyl-L-cysteinato)(diethylenetriamine)cobalt(III) complex were derived from [Co(L-cys)(dien)]+ by the reaction with dimethyl sulfate. The electronic absorption, CD, and 1H and 13C NMR spectral behaviors for these complexes are discussed in relation to their geometrical configurations.
  • Toshiro Harada, Yasunari Yamaura, Akira Oku
    1987 Volume 60 Issue 5 Pages 1715-1719
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    (ω-Oxidoalkyl)cyclopropylidenes generated from (2,2-dibromo-1-methylcyclopropyl)-CH2–X–(CH2)n–OH (X=CH2 or O, n=1, 2) by the reaction with methyllithium underwent a regioselective intramolecular insertion into the C–H bond at the δ position to the carbenic carbon. The activation effect of the oxido substituent on the reactivity of C–H bonds is discussed on the basis of (1) the ratio of the insertion products to the rearrangement product allenyl alcohol, and (2) the endo stereoselectivity of the present insertion reactions.
  • Jun-ichi Ishiyama, Satoshi Maeda, Kazuhiro Takahashi, Yasuhisa Senda, ...
    1987 Volume 60 Issue 5 Pages 1721-1726
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The chemo-selectivity of group-VIII metal catalysts has been examined in the hydrogenation of nonconjugated enones at ambient temperature under an atmospheric pressure of hydrogen. A cobalt catalyst gave high yields of unsaturated alcohols from trialkylated olefinic ketones. Osmium showed the highest selectivity among platinum metal catalysts for the reduction of the carbonyl bond in the hydrogenation of trialkylated olefinic ketones. The hydrogenation of mono- and dialkylated olefinic ketone ordinarily proceeded with a preferential saturation of the olefinic function, regardless of the catalyst. The hydrogenation of 4-methylene- and 4-ethylidenecyclohexanone was accompanied by the formation of diethyl acetals over ruthenium, rhodium, and palladium black catalysts in an ethanol solvent. The acetals were not detected in the hydrogenation of the other enones and over the other catalysts. In addition, the chemoselectivity on the hydrogenation of acyclic enones was examined over nickel and cobalt catalysts treated with small amounts of alkali and carbon monoxide. The amount of unsaturated alcohols increased when the catalyst was treated with alkali in the case of di- and trialkylated olefinic ketones, whereas the characteristics of cobalt, which selectively reduces the ketonic function in trialkylated olefinic ketones, were completely missing when cobalt was treated with carbon monoxide.
  • Kin-ichi Tadano, Yoshihide Ueno, Chiyoko Fukabori, Yukinori Hotta, Tet ...
    1987 Volume 60 Issue 5 Pages 1727-1739
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    A versatile chiral compound, (1R,6R,8R,9R)-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]non-4-en-3-one (6), was efficiently synthesized from D-glucose. The synthesis featured an intramolecular aldol cyclization of 3-C-acetylmethyl-3-deoxy-1,2-O-isopropylidene-α-D-ribo-pentodialdo-1,4-furanose, which was readily derivatized from the known Wittig adducts of 1,2:5,6-di-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose. The utility of this highly functionalized chiral synthon 6 was embodied by conversion to four optically active pseudosugars, these are pentaacetyl derivatives of pseudo-α-L-altropyranose, pseudo-β-D-glucopyranose, pseudo-2-amino-2-deoxy-β-L-altropyranose, and pseudo-2-amino-2-deoxy-α-D-glucopyranose (a derivative of pseudoglucosamine). The transformation of 6 to the pseudo sugars involved 1) a stereospecific epoxidation of the double bond in 6 providing (1R,4S,5S,6S,8R,9R)-4,5-epoxy-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]nonan-3-one (8), and 2) an exclusive diaxial ring opening of the β-epoxy alcohols, which were derived from 8, providing (1R,3R,4S,5S,6S,8R,9R)-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]nonane-3,4,5-triol (11) or (1R,3S,4S,5R,6S,8R,9R)-4-azido-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]nonane-3,5-diol. Treatment of (1R,2S,3S,4S,5R)-3,4,5-tris(benzyloxy)-2-hydroxycyclohexanecarbaldehyde, which was derived from 11, with methanesulfonyl chloride, and successive sodium borohydride reduction provided (3S,4S,5R)-3,4,5-tris(benzyloxy)-1-cyclohexene-1-methanol (19). Hydroboration of 19 proceeded from the less hindered side stereoselectively.
  • Masao Okubo, Shunsei Yoshida, Yoshiji Egami, K\={o}ji Matsuo, Shigeru ...
    1987 Volume 60 Issue 5 Pages 1741-1746
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The reactions of an aryliminodimagnesium reagent (ArN(MgBr)2) with four oxidizing agents ((i): I2, OsO4, C6H5IO2, I2O5) and four push-pull substituted α-benzylideneacetophenones(ii) were examined. In the reactions with (i), the maximum yield of sym-azobenzene was 50%. In the reactions with (ii), in addition to products formed via condensation and the typical radical processes, unexpected products formed via cleavages of C=C and Cβ–H bonds were observed. Summarizing these results, a pathway involving the formation of arylnitrene-like species via disproportionation of arylaminyl radicals (Ar\.{N}MgBr) has been proposed.
  • Hitoshi Takeshita, Akira Mori, Yasutomo Goto, Tomohiro Nagao
    1987 Volume 60 Issue 5 Pages 1747-1752
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    A reinvestigation of the Claisen rearrangement of 2,5-bis(allyloxy)tropone led to the isolation of three diallyl-5-hydroxytropolones along with an intermediary thermolysate, 3-allyl-5-allyloxytropolone. The structure of the formerly identified product was revised from 3,6-diallyl-5-hydroxytropolone to 4,6-diallyl-5-hydroxytropolone. The involvement of no cleavage-recombination process was established by cross-over deuterium labelling experiments. These derivatives were respectively converted to p-tropoquinones, one of which was further converted to a cyclohepta[b]pyranone derivative by an electrochemical reaction.
  • Hidehiko Sato, Hiroshi Nishino, Kazu Kurosawa
    1987 Volume 60 Issue 5 Pages 1753-1760
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    2-Butenamides and 2-buten-4-olides are formed by the reaction of phenyl or 4-chlorophenyl-substituted olefins with α-cyanoacetamide in the presence of manganese(III) acetate. On the other hand, aryl substituted olefins having electron-donating groups are oxidized under similar reaction conditions to give 1,5-dihydro-2H-pyrrol-2-ones and 3-ethenyl-2-pyrrolidones. All these reactions also produce glycols or ketones which are given by the direct oxidation of these olefins with manganese(III) acetate. The question whether an intermediate carbocation in the oxidation process cyclized on an oxygen or a nitrogen atom can be explained by the hard and soft acids and bases (HSAB) concept. A possible mechanism for the formation of 2-butenamides and 2-buten-4-olides is proposed.
  • Nobuto Minowa, Masao Hirayama, Shunzo Fukatsu
    1987 Volume 60 Issue 5 Pages 1761-1766
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    (S)-(+)-Phosphinothricin was prepared in good optical yield by the Michael addition of chiral glycine Schiff base derived from (S)-2-hydroxy-3-pinanone to vinyl phosphorus compound. (R)-(−)-Phosphinothricin, an enantiomeric isomer, can also be prepared from the same chiral glycine Schiff base by choosing suitable reaction temperature.
  • Katsuhiko Inomata, Shin-ichi Sasaoka, Toshifumi Kobayashi, Yuhji Tanak ...
    1987 Volume 60 Issue 5 Pages 1767-1779
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    1- or 2-p-Tolylsulfonyl(=tosyl)-1-alkenes, vinylic sulfones, were regioselectively prepared from 1-alkenes via iodosulfonization or sulfonylmercuration and also from 1-haloalkanes by the homologation or unhomologation methods. The vinylic sulfones thus prepared were further converted to the corresponding allylic sulfones under basic conditions. The stereochemistry of this conversion was discussed. One-carbon homologated allylic sulfones were directly obtained from aldehydes in good yields by the reaction with diethyl phenylsulfonylmethylphosphonate and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) under mild conditions.
  • Yoshio Tamura, Gaku Yamamoto, Michinori Oki
    1987 Volume 60 Issue 5 Pages 1781-1788
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    In the series of 4-substituted 9-ethyl-1-methoxytriptycenes, the populations of the sc conformer increase as the electron-density on the 1-methoxy–oxygen decreases. This trend was interpreted on the basis of steric repulsion which should increase as the electron density on the oxygen atom becomes high. In contrast, in the series of 9-(substituted phenoxymethyl)-1,4-dimethyltriptycenes, the high electron density on the aryloxy–oxygen favors the sc form. The stabilization of the sc form relative to the ap in the high electron density compounds in the latter series is attributed to the presence of CH3···O hydrogen bond, since other factors like Coulombic interactions, van der Waals repulsions, and van der Waals attractions could be excluded from being the main factor for the stabilization.
  • Koichiro Naemura, Yuji Kanda, Hiroshi Iwasaka, Hiroaki Chikamatsu
    1987 Volume 60 Issue 5 Pages 1789-1792
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The macrobicyclic and macrotricyclic cryptands containing the trans-tetrahydrofuran-2,5-diylbis(methylene) molecular framework as the chiral subunit were prepared in optically active forms. The enantiomer recognition property of the macrotricyclic tetracarboxamide (+)-6 in transport of enantiomeric molecules was examined, and the cation-binding abilities of the macrotricyclic and macrobicyclic amines 7, 10, and 13 were also investigated.
  • Tohru Yoshida, Nobuaki Kambe, Shinji Murai, Noboru Sonoda
    1987 Volume 60 Issue 5 Pages 1793-1799
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Five-, six-, and seven-membered cyclic ureas were synthesized in excellent yields from various aromatic diamines by reaction with carbon monoxide and a stoichiometric or excess amount of selenium in the presence of N-methylpyrrolidine. The carbonylation also proceeded using a catalytic amount of selenium in the presence of an oxidizing agent such as oxygen or dimethyl sulfoxide producing selectively the five and six-membered cyclic ureas. In the case of 2-(2-aminoethyl)aniline under the catalytic conditions, intra- and intermolecular carbonylation competed resulting in the formation of a mixture of the seven-membered cyclic urea, 1,3,4,5-tetrahydro-2H-1,3-benzodiazepin-2-one and the acyclic urea, 1,3-bis[2-(2-aminophenyl)ethyl]urea. The distribution ratio of these two products varied depending on the reaction conditions, but selective formation of the cyclic urea was attained only when a stoichiometric or excess amount of selenium was used. In addition to the above diamino compounds, 2-carbamoylaniline, 2-amino-3-pyridinol, and 2-(hydroxymethyl)aniline also underwent similar carbonylation to give 2,4(1H,3H)-quinazolinedione, oxazolo[4,5-b]pyridin-2-(3H)-one, and 1,4-dihydro-2H-3,1-benzoxazin-2-one, respectively.
  • Osamu Ishitani, Shozo Yanagida, Setsuo Takamuku, Cyongjin Pac
    1987 Volume 60 Issue 5 Pages 1801-1805
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    There were investigated photochemical behaviors of 4-alkylated 1-benzyl-1,4-dihydronicotinamides (1a–c) having R1R2C(OH) as the substituent (a: R1=Ph and R2=H; b: R1=Ph and R2=CF3; c: R1=p-NC–C6H4 and R2=H). The direct photolysis of 1a–c gave R1R2CO and the dimers of the dihydronicotinamide (BNA) fragment along with a minor amount of [C6H5CH(OH)]2, being thus interpreted in terms of the homolysis between the R1R2(OH) and BNA moieties. In the [Ru(bpy)3]2+-photosensitized reactions, it is suggested that 1a–c was generated as a key intermediate by electron transfer to excited [Ru(bpy)3]2+, undergoing a bond cleavage to give R1R2CO and the BNA. dimers. In the case of 1c, however, R1R2CH(OH) was formed, being attributed to a product from 1c−· that is formed by electron transfer from [Ru(bpy)3]+ to 1c.
  • Sadao Tsuboi, Shigetoshi Mimura, Shin-ichiro Ono, Kenji Watanabe, Akir ...
    1987 Volume 60 Issue 5 Pages 1807-1812
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Direct oxidation of 2,4-alkadienoic esters with selenium dioxide gave 5-alkyl-2-furancarboxylic esters along with 5-alkyl-2-selenophenecarboxylic esters. Ethyl 5-methylfurancarboxylate was converted to 5-hydroxymethyl-2-furancarbaldehyde, a component of honey, via ethyl 5-bromomethyl-2-furancarboxylate (5) in good yield. The compound 5 was converted to (5-ethoxycarbonyl-2-furyl)methyl dimethyldithiocarbamate possessing fungicidal activity. Reaction of triphenylphosphonium salt of 5 with nonanal gave ethyl 5-(1-decenyl)-2-furancarboxylate (E/Z=88:12) in 86% yield. Ethyl 5-methyl-2-selenophenecarboxylate was also converted to ethyl 5-(1-decenyl)-2-selenophenecarboxylate (E/Z=7:3) in 30% total yield.
  • Atsuhiro Ookawa, Hiroshi Hiratsuka, Kenso Soai
    1987 Volume 60 Issue 5 Pages 1813-1817
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Mono- and gem-disubstituted epoxides were reduced to more substituted alcohols in good to high yields (73–100%) and in high regioselectivities (89–100:11–0) by sodium borohydride in a mixed solvent of t-butyl alcohol–methanol or 1,2-dimethoxyethane-methanol. The reaction of disubstituted epoxide depends on the steric hindrance and the position of the substituents. Trisubstituted epoxides were not reduced by the present reducing system. The reactivity order of epoxides by the present reducing system was mono->2,2-di->2,3-di->>trisubstituted epoxides. The chemoselectivity of the present reducing system is excellent. Thus, epoxides were selectively reduced in the presence of such reducible groups as carbamoyl, carboxyl, nitro, cyano, and bromo.
  • Seiji Shinkai, Tohru Yoshida, Kiminori Miyazaki, Osamu Manabe
    1987 Volume 60 Issue 5 Pages 1819-1824
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The aggregation properties of photoresponsive crown ethers (1) having a crown ring and an ammonioalkyl (H3N+–(CH2)n, n=4, 6, 10) group attached to the two sides of an azobenzene have been evaluated through the measurements of average molecular weights and electric conductance. Osmometric determination of average molecular weights established that all trans-isomers (trans-1 (n=4, 6, 10)) form the pseudocyclic dimers due to intermolecular crown-ammonium complexation. Photoisomerized cis-1 (n=6) and cis-1 (n=10), which have been designed so that intramolecular “biting” of the ammonio group to the crown can occur upon photoisomerization, existed as the discrete monomers. On the other hand, cis-1 (n=4), which cannot form the intramolecular “tail-biting” complex because of the short tetramethylene spacer, existed as the pseudo-cyclic dimer. This difference was well reflected by electric conductance: in 1 (n=6) and 1 (n=10), the conductance increased synchronously with trans-to-cis photoisomerization and decreased with cis-to-trans photoisomerization. Such a photoresponsive conductance change was scarcely detected for 1 (n=4). Furthermore, the additives which enforce dissociation of the dimeric species to the monomeric species suppressed the magnitude of the photoinduced conductance change. This is a novel example that the light energy is transmitted to the conductance change.
  • Sinichi Otani, Shiro Hashimoto
    1987 Volume 60 Issue 5 Pages 1825-1829
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Cyclization, with nitroethane in the presence of sodium methoxide, of the dialdehyde produced by periodate oxidation of methyl β-D-glucopyranoside and acetylation led to methyl 2,4,6-tri-O-acetyl-3-C-methyl-3-nitro-β-D- and -α-L-glucopyranoside (1, 12% and 2, 8.8%). In the case of methyl α-D-glucopyranoside, products 3 (8.6%) and 4 (8.0%) were antipodes of 1 and 2, respectively. Denitrohydrogenation of 1 or 3 with tributyltin hydride in toluene led to 3-deoxy-3-C-methyl-β-D-pyranosides (gluco, 5, 61% and allo, 6, 22%) or L-pyranosides (gluco, 9, 65% and allo, 10, 19%), respectively. This sequence of the reaction was a novel method for the syntheses of 3-deoxy-3-C-methyl-L-glucose and -L-allose. Denitrohydrogenation of 2 or 4 led to a mixture of 3-deoxy-3-C-methyl-α-L-pyranosides (allo, 7, 39% and gluco, 8, 41%) or mixture of 3-deoxy-3-C-methyl-α-D-pyranosides (allo, 11, 38% and gluco, 12, 41%), respectively. Methyl 2-O-acetyl-4,6-O-benzylidene-3-deoxy-3-nitro-β-D-glucopyranoside was denitrohydrogenated to the corresponding 3-deoxy sugar (14) in 68% yield.
  • Takayuki Kawashima, Takafumi Ishii, Naoki Inamoto
    1987 Volume 60 Issue 5 Pages 1831-1837
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Dimethyl α-trimethylsilylbenzylphosphonate was allowed to react with carbonyl compounds in the presence of fluoride ion to give the corresponding olefins in fairly good yields. Use of CsF in tetrahydrofuran gave the best result. On the other hand, dimethyl trimethylsilylmethylphosphonate was allowed to react similarly with benzophenone to afford 1,1-diphenylethylene, dimethyl methylphosphonate, and dimethyl 2,2-diphenylethenylphosphonate. A similar result was obtained by using O,O-diethyl trimethylsilylmethylphosphonothioate. But, reaction of trimethylsilylmethylphosphonic bis(diethylamide) afforded only the protodesilylation product.
  • Tsuyoshi Satoh, Masayuki Itoh, Teruhiko Ohara, Koji Yamakawa
    1987 Volume 60 Issue 5 Pages 1839-1846
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Treatment of the α,β-epoxy sulfoxides derived from ketones and chloromethyl phenyl sulfoxide or 1-chloroalkyl phenyl sulfoxides with lithium perchlorate in the presence of tributylphosphine oxide in toluene at 110 °C for about 1–3 h gave α,β-unsaturated aldehydes or α,β-unsaturated ketones in high yields. In contrast to these results, the α,β-epoxy sulfoxides derived from aldehydes did not give the desired α,β-unsaturated ketones. In this case, a sequential treatment of the α,β-epoxy sulfoxides with benzenethiolate and m-chloroperbenzoic acid afforded α-phenylsulfinylated ketones, which were heated in toluene at 110 °C to give the desired enones in good overall yields. The oxidation of the α,β-unsaturated aldehydes obtained by this method gave α,β-unsaturated carboxylic acids in high yields. These procedures afforded a new method for the synthesis of α,β-unsaturated carbonyl compounds, including α,β-unsaturated esters, from carbonyl compounds with carbon homologation.
  • Kazuhiro Maruyama, Hitoshi Tamiaki
    1987 Volume 60 Issue 5 Pages 1847-1851
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Photochemical reaction of 2,3-dichloro-1,4-naphthoquinone (1) with thiophenes 2 afforded 2-chloro-3-(2-thienyl)-1,4-naphthoquinones. The reaction might be initiated by the photoelectron transfer from 2 to 1, resulting in the formation of combined products via recombination of the formed ion radicals 1\ ewdot and 2\underset.+ by accompanying elimination of chloro and hydro radicals. In the photoreaction, reactivity of 2 was estimated from the observed oxidation potentials of 2 and the calculated electron densities in 2\underset.+.
  • Syuichi Matsui
    1987 Volume 60 Issue 5 Pages 1853-1865
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Treatment of γ-butyrolactone with bis[ethoxy(thiocarbonyl)] disulfide in the presence of 2.2 equiv of lithium diisopropylamide (LDA) produced lithium enolate of O-ethyl S-(tetrahydro-2-oxo-3-furanyl) dithiocarbonate, which reacted with an aldehyde to afford exclusively (E)-α-alkylidene-γ-butyrolactone. Interestingly, when the reaction was quenched below −20 °C or when it was carried out in the presence of metal complex such as zinc chloride, copper(I) iodide, or tributyltin chloride, (Z)-α-alkylidene-γ-butyrolactone was obtained as the major product. The stereoselectivity of this reaction was sensitive to the reaction temperature and the metal cation employed.
  • Akikazu Kakehi, Suketaka Ito, Shingo Yonezu, Katsunori Maruta, Kazuhir ...
    1987 Volume 60 Issue 5 Pages 1867-1879
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Alkaline treatment of 1-[2-(substituted methylthio)vinyl]pyridinium bromides, readily obtainable from the S-alkylation of pyridinium 1-(thiocarbonyl)methylides with various alkyl bromides such as bromoacetonitrile, ethyl bromoacetate, and some phenacyl bromides, gave smoothly 1,9a-dihydropyrido[2,1-c][1,4]thiazine derivatives as almost isomeric mixtures. These dihydropyridothiazines are very unstable and decomposed rapidly at ordinary temperature, but by treating them with a dehydrogenating agent such as lead tetraacetate (LTA) or 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) at 0 °C the desulfurized and the rearranged aromatic indolizine derivatives were formed in moderate to good yields.
  • Yasuo Shida, Kazuo Tsujimoto, Takashi Ikeda, Mamoru Ohashi
    1987 Volume 60 Issue 5 Pages 1881-1886
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The in-beam EIMS and SIMS of three quaternary ammonium chlorides of benzylamine derivatives have been examined, and their fragmentation processes have been clarified by means of the BE costant and B2E constant linked scanning techniques. The BE constant linked scan of the benzyltrimethylammonium ion (mz 150) in the in-beam EIMS indicated a fragment ion at mz 126 as a daughter ion. A substitution reaction between the mz 150 ion and a chlorine atom in the first field free region is proposed. The characteristics of SIMS of those compounds were demonstrated in comparison with those of EIMS and the fragmentation processes of the salts upon Xe+ bombardment were established based on the linked scanning techniques.
  • Hiroshi Awano, Kazuo Takemoto, Hirohisa Ohya, Minaki Tomio, Seizo Tama ...
    1987 Volume 60 Issue 5 Pages 1887-1893
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Metal ion catalyzed reduction of substituted nitrosobenzenes by 1-benzyl-3,5-bis(1-pyrrolidinylcarbonyl)1,4-dihydropyridine (BPDH) in acetonitrile has been studied for seven bivalent metal ions. The reduction of N-methylacridinium salt (MA) has also been examined. In the former cases, it was found that the metal ions catalyze the reduction by forming a 1:1 complex with BPDH according to a Michaelis–Menten type saturation kinetics which allowed to derive the association constants, KM, for the complexation and the second-order rate constants, k2, for the reduction. A linear relationship was found between logk2 and the ionization potentials of metal ions with a positive slope. A linear Hammett relationship was also observed between logk2 and the Hammett σ constants with a positive ρ value for three metal ions. These results suggest that a bivalent metal ion is sandwiched between the BPDH and the substrate and acts as a Lewis acid to stabilize the incipient N-oxide anion of the substrate which is formed by hydride transfer in the transition state. In the cases of MA, all metal ions inhibited the reduction. Repulsion between the positive charges of the metal ion-BPDH complex and the substrate salt appears to be prevailing.
  • Yun Chen, Kazuhiko Saigo, Noriyuki Yonezawa, Masaki Hasegawa
    1987 Volume 60 Issue 5 Pages 1895-1902
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The chiroptical property of optically active polyamides (3a–i), derived from (−)-anti head-to-head coumarin dimer (1), was investigated by comparing their UV and circular dichroism (CD) spectra with those of the corresponding model diamides (8a–i) in the film state. The result suggests that the polyamides (3a–c,g) derived from acyclic aliphatic diamines, exist in a random conformation due to the flexibility of the diamine components. The polyamides (3d,h), consisting of piperazine, are assumed to be in a rod-like conformation, resulting from their rigid and fixed main chains. The polyamides (3e,f,i), prepared from aromatic diamines, show reversed and split Cotton effects at 270–300 nm in comparison with those of model diamides. This phenomenon is interpreted by the formation of an ordered conformation of macromolecular asymmetry.
  • Kazunari Taira
    1987 Volume 60 Issue 5 Pages 1903-1909
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The cleavage of poly(uridylic acid) by imidazole buffer was studied recently by Breslow and Labelle, and a bell-shaped profile was observed for the rate vs. buffer protonation state. The reaction, however, was kinetically first-order in buffer (R. Breslow and M. Labelle, J. Am. Chem. Soc., 108, 2655 (1986)). The sequential base-acid mechanism proposed by those authors is in agreement with the expectation based on the stereoelectronic effects. In addition, the alternative sequential acid-base mechanism, which could not be excluded on the basis of their kinetic data, may be excluded based on the stereoelectronic considerations.
  • Makoto Aihara, Masahiro Komatsu
    1987 Volume 60 Issue 5 Pages 1911-1912
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Glassy carbon electrode polished with ceramics particles (TiB2, SiC, and TiC) showed higher oxidation rate of ascorbic acid. The activation seems to depend on hardness of glassy carbon and ceramics particles and to be influenced by fresh edges formed on glassy carbon surface.
  • Shuji Emori, Nobuhide Morishita, Yoneichiro Muto
    1987 Volume 60 Issue 5 Pages 1913-1914
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Compounds of formula Cu(XCH2COO)2·nACl (A=NH4, CH3NH3, (CH3)2NH2, (CH3)4N and X=F, Br) have been prepared, and characterized by magnetic susceptibility and IR spectroscopy measurements. Factors affecting the magnetic moments of copper(II) salts of monosubstituted alkanoic acids are discussed.
  • Akira Oku, Yukio Homoto
    1987 Volume 60 Issue 5 Pages 1915-1916
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Potassium 1-(dimethylamino)naphthylide (K+DMAN\ ewdot) was protonated by aqueous THF and the structures of protonated products (overall yield of three isomeric products was almost quantitative) were analyzed by 1H NMR and their 2D-NOE correlation. Products were 1-(dimethylamino)-5,8-dihydronaphthalene (major product, 88%), 7,8-dihydro- (9%), and 5,6-dihydro-isomer (3%). Deducing from the structures, the protonation pathway as well as the spin distribution in K+DMAN\ ewdot is discussed.
  • Atsushi Sakurai, Yohko Goto
    1987 Volume 60 Issue 5 Pages 1917-1918
    Published: 1987
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    A new ortho-depside, isolecanoric acid was isolated from Parmelia tinctorum Despr. and 2-(2,4-dihydroxy-6-methylbenzoyloxy)-4-hydroxy-6-methylbenzoic acid was assigned to this substance from studies on the hydrolysis products and from analyses of the 1H and 13C NMR spectra. This substance is the first ortho-depside isolated from the genus Lichen.
feedback
Top