Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
56 巻 , 1 号
選択された号の論文の82件中1~50を表示しています
  • Tadao Kenjo, Noriyuki Nakajima
    1983 年 56 巻 1 号 p. 1-5
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The polarization characteristics of poly(tetrafluoroethylene)-bonded Raney nickel hydrogen- and silver oxygen-electrodes have been measured as a function of the thickness of the catalyst layer, and the polarization curves of these electrodes have been analyzed on the basis of the electrolyte film model. The observed polarization curves were divided into several segments and a linear polarization-current equation, derived from the model, has been applied to each segment. The performance of the electrodes approaches asymptotically to an upper limit with the thickening of the catalyst layers. The profiles of the faradayic current density across the electrode wall have been estimated for both electrodes. In contrast with the almost flat profiles of the Raney nickel electrodes, the current densities for the silver electrodes are localized on the liquid side of the electrodes; a thin area of the catalyst layer ranging from the electrode-face/electrolyte interface to 5.3×10−3cm distance sustains most of the load current at a polarization of 220 mV. The catalytic activities of both the silver and Raney nickel catalysts are enhanced with progression of the polarization while the resistivities of the electrolyte film maintained essentially constant. A slight surface oxidation for the Raney nickel and a surface reduction for the silver catalysts have been suggested as probable explanations for the enhanced catalytic activities observed.
  • Tetsuo Moriya
    1983 年 56 巻 1 号 p. 6-14
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The kinetics and mechanism of the reaction in the photo-excited state of 7-hydroxycoumarin and its derivative have been studied in aqueous solutions by means of measuring the fluorescence spectra and the fluorescence lifetime. The four fluorescence bands have been identified as emissions from the neutral, anionic, tautomeric, and cationic forms of 7-hydroxycoumarins. The quantitative analysis was performed by using the rate equation which included the term for the direct conversion of the excited neutral molecule to its tautomer in addition to the usual reaction term of dissociation. The rate constants of the tautomerization and dissociation were discussed in detail, and it was revealed that the tautomerization in aqueous solutions was mainly caused by the transfer of a proton between two active sites in the molecule. Such an intramolecular proton-transfer of the coumarins, found first in this paper, is considered to be promoted by water molecules with a hydrogen bond surrounding the excited molecule.
  • Tatsuo Erabi, Masaya Tanaka
    1983 年 56 巻 1 号 p. 15-18
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Carbon-paste electrodes were prepared with use of ubiquinone-10 dissolved in organic liquids, 1-chloronaphthalene, 1-bromonaphthalene, 1-methylnaphthalene and undecane. Ubiquinone-10 shows a well-defined, pH-dependent cathodic reduction wave in each liquid system and its reduction seems to proceed with two electrons and a proton transfer around neutral pH. The experimental results indicate the wave to be diffusion-controlled, and the apparent diffusion coefficient was additionally calculated in each liquid system.
  • Takeshi Kyogoku, Toshifumi Watanabe, Shigeru Tsunashima, Shin Sato
    1983 年 56 巻 1 号 p. 19-21
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The absolute rate constants of the H and D atom addition to 1-butene, cis- and trans-2-butenes, and isobutene have been measured over the temperature range 200–500 K at the total pressure of about 600 Torr (1 Torr=133.3 Pa). The rate constants obtained were well expressed by the Arrhenius equations: k(H+1-butene)=(2.48±0.43)exp[−(1492±94)⁄RT], k(H+cis-2-butene)=(2.67±0.39)exp[−(1918±83)⁄RT], k(H+trans-2-butene)=(3.96±0.27)exp[−(2096±37)⁄RT], k(H+isobutene)=(2.08±0.16)exp[−(860±49)⁄RT], k(D+1-butene)=(2.42±0.72)exp[−(1642±169)⁄RT], k(D+cis-2-butene)=(2.25±0.19)exp[−(2082±48)⁄RT], k(D+trans-2-butene)=(2.33±0.23)exp[−(2036±55)⁄RT], and k(D+isobutene)=(1.54±0.19)exp[−(879±81)⁄RT] in units of 10−11 cm3 molecule−1 s−1. The isotope effects due to the difference between H and D atoms can simply be explained by the difference in collision frequency. The difference between cis- and trans-2-butenes in reactivity may be explained in terms of the pre-exponential factors.
  • Isao Sekine, Masahiro Asazuma
    1983 年 56 巻 1 号 p. 22-26
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The addition of shoyu (soy sauce) oil to an NaCl solution for use as a corrosion inhibitor of SS 41 steel was investigated by measuring the corrosion weight loss, the polarization curve, the polarization resistance, and the impedance of the metal-solution interface. The value of the weight loss and the double-layer capacitance, Cdl, decreased as the shoyu oil was added to NaCl solutions of various concentrations. The value of the corrosion current density, Icorr, as calculated from the weight loss, the polarization curve, and the impedance measurement, decreased with an increase in the concentration of shoyu oil. An efficient inhibition of the corrosion of SS 41 steel was observed above an additive concentration of about 0.3%. Thus, the shoyu oil was found to be useful as a corrosion inhibitor of an economical and anti-pollution type. From the results of the IR analysis, the inhibition of the shoyu oil was considered to be caused by the adsorption of fatty acids, especially unsaturated fatty acids involved in the shoyu oil.
  • Eiji Chino, Yoshio Matsunaga, Noboru Tanabe
    1983 年 56 巻 1 号 p. 27-30
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Electromotive force (emf) measurements were made on solid-state galvanic cells, Ag|AgI|TTT–In, where TTT–In is the 5,6:11,12-bis(epidithio)naphthacene–iodine complex, as functions of the composition, n, and also of the temperature. A continuous increase in the emf at 25 °C from 491 to 593 mV was observed in the range from n=1.0 to 1.5, suggesting the occurrence of a nonstoichiometric phase. The upper limit of the existence region agrees with the composition of the well-known metallic phase. The emf changes again continuously up to 628 mV in the range from n=2.7 to 2.9, which corresponds with the composition of another highly-conducting complex. Similar measurements were carried out for the cells Ag|AgBr|TTT–Brn. Distinct phases were found at the following compositions: n=0.5–0.8, about 1, about 1.2, about 1.5, and about 2. The Gibbs energy, enthalpy, and entropy of cell reactions as well as complex formation reactions were estimated.
  • Hiromichi Sagitani, Stig E. Friberg
    1983 年 56 巻 1 号 p. 31-34
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Phase regions were determined in systems with water and sodium dodecyl sulfate combined with a series of nonionic surfactants of the structure di-, tetra-, hexa-, and octaoxyethylene dodecyl ethers. The results showed the more hydrophobic members to act as cosurfactants, stabilizing the lamellar structure at high water contents. The more hydrophilic members of the nonionic series acted in a manner similar to ionic surfactants with a slight tendency to stabilization of the lamellar phase for 1:1 combinations of the surfactants.
  • Haruka Yamada, Masao Saheki
    1983 年 56 巻 1 号 p. 35-40
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    An infrared ATR apparatus for use at low temperatures was constructed for the determination of the optical constants and absorption intensities of crystalline samples. The ATR spectra of benzene and carbon disulfide polycrystals were measured with two different incident angles. The optical constants and then the absorption intensities were accurately obtained for the fundamental bands from these ATR spectra. Experiments for transmission spectra were also carried out with an improved absorption cell at low temperatures, confirming the present ATR results. A comparison of the intensities in different phases was made for the ν18, ν19, ν20, and ν11 fundamental bands of benzene and the ν3 band of carbon disulfide.
  • Kazutoshi Iwamoto, Shun-ichi Mitomo, Manabu Sen\={o}
    1983 年 56 巻 1 号 p. 41-45
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    A chemical system having a mnemonic function is constructed and its behavior is analyzed. The system consists of a subsystem having seven steady states and, under suitable conditions, it stays in a stable steady state or in an oscillating state depending on the initial state. Moreover, the system can show an additional oscillating state around the oscillating state and transitions between two different oscillating states occur by a little change in a certain parameter value(input), which is the characteristic point in this system. Therefore, a response behavior of the system to an input differs drastically depending on the states, i.e., oscillating or stationary. This property could be related to appearance of a mnemonic function. Moreover, it is demonstrated that the system could be linked with an excitable subsystem to show more clearly the mnemonic function proposed here.
  • Akihiko Kanemoto, Sigeya Niizuma, Siro Konishi, Hiroshi Kokubun
    1983 年 56 巻 1 号 p. 46-50
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    F-pair polarization and triplet mechanism (TM) polarization of durosemiquinone radical produced by light irradiation of duroquinone-phenol systems were discriminated at 260 K in a simple way based on the analysis of the enhancement factors in the steady-state method with intermittent light irradiation. Both polarizations are not so sensitive to viscosity or polarity of solvents. TM enhancement factor is nearly constant (−0.8) in wide range of viscosity (2.5–25 cP, 1 cP=0.001 Pa s). F-pair polarization is suppressed in some extent by halogenated solvents while TM polarization is not affected by such solvents.
  • Tomoko Sato-Toshima, Akeji Kamaguchi, Keiichi Nishiyama, Minoru Sakiya ...
    1983 年 56 巻 1 号 p. 51-54
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Standard energies of combustion at 298.15 K have been determined for crystalline acetanilide and nicotinic acid by static oxygen bomb calorimetry. Derived standard enthalpies of combustion and of formation are −(4224.8±1.0) and −(209.5±1.5) kJ mol−1 for acetanilide, and −(2730.83±0.48) and −(344.81±0.92) kJ mol−1 for nicotinic acid, respectively. Nicotinic acid pellets of 1.2 g in mass showed remarkable tendency to spatter when partially burnt. Factors governing the completeness of combustion of the material have been explored through 28 test combustion experiments.
  • Kiwamu Yamaoka, Mitsuaki Shimadzu
    1983 年 56 巻 1 号 p. 55-59
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The linear dichroic spectra of the neutral (uncharged) and divalent (doubly charged) Acridine Orange, Acridine Yellow, and Proflavine were measured at 25 °C in the visible and UV wavelength regions by the film dichroism method. These 3,6-disubstituted symmetric acridine dyes were molecularly dispersed in the heattreated poly(vinyl alcohol) film by the staining method. The neutral and divalent dye species were prepared by adding a sufficient amount of sodium hydroxide or sulfuric acid to the staining dye solutions. The wavelength dependence of the reduced dichroism, ΔA/A, of the neutral species at a given stretch ratio was very similar to that of the monovalent species previously reported [Bull. Chem. Soc. Jpn., 52, 3163 (1979)]. Values of ΔA/A for the divalent species were nearly constant over the entire wavelength region 550–220 nm. The long-axis and short-axis polarized component (Az and Ay) spectra were computed for the neutral dye species from the observed parallel- and perpendicular-polarized dichroic spectra by using a reduction procedure. The broad, principal band of each dye species in the visible region was deduced to be a composite of two orthogonal (a strong Az and a weak Ay) electronic transitions.
  • Kiwamu Yamaoka, Kiyohiro Fukudome
    1983 年 56 巻 1 号 p. 60-65
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The effect of polydispersity on transient electric birefringence (EB) was examined for a dilute solution which contains like macromolecules of varying lengths. The molecules were assumed to be rigid rods of cylindrical symmetry, so that the molecular weight is linearly proportional to length. Polydispersity was expressed by the ratio of the weight-average to the number-average lengths lw/ln. A logarithmic-normal type continuous length distribution was generally used. Calculations were performed for the birefringence-average relaxation time ⟨τ⟩EB and initial slope ⟨S⟩EB as a function of the electric field strength E, which is applied prior to the start of the decay process, with the electric parameter (βw)2/2γw, which is related to the weight-average permanent dipole moment (the βw-term) and polarizability anisotropy (the γw-term). Both ⟨τ⟩EB and ⟨SEB are very sensitive to E, lw/ln, and (βw)2/2γw. A convenient method was devised for determining the polydispersity parameters (lw/ln and lw) from the weight-averages of relaxation time and initial slope, which are free from the mechanism of field orientation. Examples are given for a polydisperse, rigid rodlike sonicated DNA sample in aqueous solution.
  • Hiroshi Suzuki, Keiichiro Ogawa, Tadamasa Shida, Akira Kira
    1983 年 56 巻 1 号 p. 66-74
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The radical ions of (Z)-stilbene and its α,β-dialkyl derivatives were produced by γ-ray irradiation of the parent compounds in frozen matrices at 77 K, and their geometries were investigated by electronic absorption spectroscopy. While the relaxed geometries of the radical ions of (Z)-stilbene are probably similar to that of the neutral molecule, those of the radical ions of the α,β-dialkyl derivatives are appreciably different from those of the neutral molecules: The torsion angle of the central ethylenic bond is distinctly larger and that of each C–Ph bond is probably smaller in the radical ions than in the neutral molecules. On illumination the radical ions of (Z)-stilbene isomerize to the E isomers, but those of the α,β-dialkyl derivatives do not. A mechanism of the photoisomerization is proposed, and an interpretation of the difference in the photochemical behavior between the unsubstituted stilbene radical ions and the α,β-dialkyl derivatives is given.
  • Katumitu Hayakawa, Mitsuo Kanda, Iwao Satake
    1983 年 56 巻 1 号 p. 75-81
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The spectrophotometric study was made of the oxidation of formate by iodine in micellar solutions of decyl- and dodecyltrimethylammonium chlorides. In the presence of the cationic surfactant micelles, the reaction was found to take place only at the micellar surface according to the same mechanism as in water. The experimental second-order rate constant rose steeply to a maximum at the critical micelle concentration and then decreased monotonously with increasing surfactant concentration. A tentative estimation based on a charged-phase separation model led to the true second-order rate constant in micellar phase of 0.03–0.07 mol−1 dm3 s−1 at 30 °C, which is comparable with that in water. Thus the observed rate enhancement in cationic surfactant solutions can be interpreted in terms of an increase in surface concentration of the formate ion arising from an electrostatic interaction with the micellar ion. The micellar effects on the formation constant of triiodide ion are also discussed.
  • Tatsuo Izumida, Kuniaki Fujii, Masaaki Ogasawara, Hiroshi Yoshida
    1983 年 56 巻 1 号 p. 82-85
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Broad structureless charge-transfer (CT) bands of benzyl radical-halide ion (\dotBz- - -X) complexes have been observed in 3-methylhexane (3MHx) and 2-methyltetrahydrofuran (MTHF) matrices containing BzCl and BzBr irradiated with γ-rays at 4.2 K. 3MHx and ethanol matrices containing BzI also showed the CT band when warmed from the irradiation temperature to 77 K. These observations are in marked contrast with previous ones in which the CT band was found to be present only in alkane matrices when irradiated at 77 K. The CT band has been found to shift to the blue with increasing matrix polarity, as expected from a large contribution of the solvation of the ion to the CT transition energy of the radical-anion complex. The observed nature and behavior of the CT bands indicates that the dissociative electron attachment reaction in the matrices is a stepwise process: The formation of a \dotBz- - -X complex and its dissociation. These steps proceed readily in more polar environments and for lighter ions. For the electron attachment to BzI at 4.2 K, an even earlier step, an ionic entity prior to the C–I bond dissociation, was indicated.
  • Satoru Onaka, Yoshinori Kondo, Nobuhiro Furuichi, Koshiro Toriumi, Tas ...
    1983 年 56 巻 1 号 p. 87-94
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Photochemical degradation of a series of tin-manganese bonded complexes was studied. The apparent reactivity of the tin-manganese bond toward UV irradiation is interpreted on the basis of absorption spectra of relevant complexes and available emissions from the light source. Two kinds of orthometalated products were obtained from photolysis of Me3Sn–Mn(CO)3[P(OPh)3]2 in benzene. Various kinds of experiments suggest that their photochemical reactions proceed through homolytic cleavage of the Sn–Mn bond in the initial stage and the resulting 15-electron intermediates abstract hydrogen from the triphenyl phosphite moiety. Molecular structures of the two kinds of orthometalated products, as clarified by X-ray structure analyses, are described.
  • Kuninobu Kasuga, Takeo Nagahara, Akira Tsuge, Kunihisa Sogabe, Yasuo Y ...
    1983 年 56 巻 1 号 p. 95-98
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Seven new cobalt(II) complexes with a tetradentate Schiff base and their three oxygen adducts were synthesized. The adducts were stable at room temperature for several weeks. The isolated oxygen adducts showed intense new bands in the 1130–1150 cm−1 range characteristic of superoxide-like 1:1 oxygenated metal complexes. The ESR spectra of the adducts showed eight-lined, hyperfine structures with a very small splitting (10–20 G) at 77 K. The adducts obtained were identified as monomeric 1:1 oxygen species, two complexes of which showed a reversible oxygenation in a 1,2-dichloroethane solution at 6 °C.
  • Hajime Kanatomi
    1983 年 56 巻 1 号 p. 99-104
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Nickel(II) acetate tetrahydrate and rac- and meso-2,2′-[(1,2-diphenylethylene)bis(iminomethylene)]diphenol (rac- and meso-BzPhen-H2) formed pale green complexes in methanol. A pyridine solution of these complexes deposited deep red diimine complexes after prolonged heating under aerobic conditions. The saturated ligand system of the initial complexes was dehydrogenated to an unsaturated one by molecular oxygen. From the pyridine solution of the meso-isomzr, [2,2′-(cis-1,2-diphenylethenylene)bis(nitrilomethylidyne)diphenolato]nickel(II)([Ni(SalStil)]) was isolated in addition to the diimine complex ([Ni(meso-SalPhen)]). In this case, the (Remark: Graphics omitted.) bridge was dehydrogenated to (Remark: Graphics omitted.) conjugated double bonds; that is, a fully conjugated metal chelate was formed by the dehydrogenation of the coordinated ligand.
  • Yoshio Shijo, Tokuo Shimizu, Kaoru Sakai
    1983 年 56 巻 1 号 p. 105-107
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The spectrophotometric method for the determination of trace amounts of antimony(III), bismuth, indium, and gallium based on the solvent extraction of the ion associate formed between anionic metal–Pyrocatechol Violet complexes and tridodecylethylammonium bromide is proposed. The maximum absorbance of the extracted species occur at 530, 564, 600, and 595 nm for antimony(III), bismuth, indium, and gallium. The molar absorptivities for antimony(III), bismuth, indium, and gallium are 3.32×104, 3.31×104, 8.20×104, and 8.00×104 dm3 mol−1 cm−1. The optimum pH ranges for the extraction of antimony(III), bismuth, indium, and gallium are from 3.7 to 4.8, from 5.8 to 6.7, from 5.3 to 5.4, and from 5.5 to 6.2 respectively. The composition of the extracted complexes (metal:PV:TDEA) are estimated to be 1:2:3 for antimony(III) and 1:2:2 for the other metals. The interference of foreign ions is described.
  • Hanako Kobayashi, Ikuji Tsujikawa, Takashi Shibahara, Norikiyo Ury&uci ...
    1983 年 56 巻 1 号 p. 108-112
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Sodium [μ-(ethylenediaminetetraacetato)-di-μ-sulfido-bis{oxomolybdate(V)}]·n-hydrates, n=2 and 3, are antiferromagnetic dimers with an exchange interaction within a pair of Mo(V) ions of about −140 k having an averaged g-value of about 2 for each Mo(V) ion. In these salts, magnetic moments of only about 0.5 Bohr magneton are localized at Mo(V) sites, though Mo(V) has one electron in the 4d orbital. Here a π-bonding looped structure is considered to have a contribution to the diamagnetic susceptibilities of about −5.0×10−5 (CGSemu). Sodium [μ-(ethylenediaminetetraacetato)-di-μ-oxo-bis{oxomolybdate(V)}]·n-hydrates, n=3, 4, and 6, are the antiferromagnetic dimers with an exchange interaction within a pair of Mo(V) ions of about −150 k and an averaged g-value of 1.91. The magnetic moments of only about 0.5 Bohr magneton are localized at Mo(V) sites. In these salts, too, a π-bonding structure in each dimer is considered to make a contribution to the diamagnetic susceptibility of about −4.0×10−5 (CGSemu). A broad minimum of the molar magnetic susceptibility of [μ-(ethylenediaminetetraacetato)-di-μ-oxo-bis{oxomolybdate(V)}] salts was considered due to the conformation interconversion.
  • Shuhei Fujinami, Takao Hosokawa, Muraji Shibata
    1983 年 56 巻 1 号 p. 113-121
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Seventeen kinds of fac(a,b,NH3)-[Co(a)(b)(NH3)(tacn)]n+ complexes (a, b=CN, NO2, SO32−, NCS, N3, CH3COO, H2O, OH, Cl, or Br; tacn=1,4,7-triazacyclononane) have been prepared and optically resolved by column chromatography. The absolute configurations of these complexes have been determined by referring to the CD spectra of the related [Co(a)(gly)(tacn)]n+ complexes (a=CN, NO2, NCS, N3, or Cl). It has been found that the signs of the Cotton peaks observed in the first absorption band region are closely related to the ligand field strengths of the unidentate ligands, and that the dominant Cotton peak is associated with the electronic transition which arises in the plane containing no ammonia molecule.
  • Terufumi Fujiwara
    1983 年 56 巻 1 号 p. 122-126
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The kinetics of racemization of the anhydrous complexes (−)-[Co(phen)3]X3, (+)-[Co(phen)2(en)]X3, and (−)-[Co(phen)(en)2]X3, where phen=1,10-phenanthroline, en=ethylenediamine, and X=Cl, Br, or I, have been examined in the solid state. A rapid initial loss of optical activity and a subsequent first-order racemization were observed for the complex salts. Enthalpies and entropies of activation, ΔH\ eweq and ΔS\ eweq, were evaluated for the first-order process of [Co(phen)3]X3 and [Co(phen)2(en)]X3. It was found that for [Co(phen)3]X3 the chloride salt racemizes more rapidly than the bromide salt and that ΔH\ eweq and ΔS\ eweq, decrease with the lattice anion in the order X=Br>Cl. On the other hand, the reverse sequence in ΔH\ eweq and ΔS\ eweq, X=Br<Cl, was observed for [Co(phen)2(en)]X3. Moreover, the rate of racemization of [Co(phen)(en)2]X3 was found to decrease with the lattice anion in the order X=I>Br>Cl. These anion effects for the series were successfully interpreted in terms of the chemical interactions due to donicity and hydrogen bonding ability of anions, but not in terms of the physical factor, lattice energy. Thermal decomposition studies of the complexes lend support to the interpretation of the racemization kinetic data.
  • Takaji Yasui, Hiroshi Kawaguchi, Norio Koine, Tomoharu Ama
    1983 年 56 巻 1 号 p. 127-133
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Unsymmetrical-facial (u-fac) and symmetrical-facial (s-fac) isomers of a mixed-ligand type complex, [Co(ida)(Rida)] (Rida denotes N-methyl- or N-ethyliminodiacetate dianion), were prepared and characterized on the basis of their absorption, circular dichroism, 1H NMR, and 13C NMR spectral data. The isomerization and racemization reactions of these isomers were investigated in basic aqueous solution and compared with those of the bis type complexes, [Co(ida)2] and [Co(Rida)2]. The time-course changes in the absorption spectra of [Co(ida)(Rida)] and [Co(ida)2] indicated that the mer isomer exists as a transient labile intermediate in the isomerization reaction of u-fac to s-fac.
  • Naohide Matsumoto, Akira Ohyoshi
    1983 年 56 巻 1 号 p. 134-138
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The title complex prepared through an electrophilic substitution of (11,13-diemthyl-1,4,7,10-tetraaza-10,12-cyclotridecadienato)nickel(II) bromide with p-methylbenzoyl chloride was subjected to single-crystal X-ray diffraction analysis. The analysis has revealed completion of the substitution reaction, pseudo C2 symmetry of the macrocyclic complex minus the substituent, and an essentially square planar coordination environment with slight tetrahedral distortion. The substituted p-methylbenzoyl group is tilted with respect to the least-squares plane of the conjugated six-membered chelate ring, where the dihedral angle between them is 69.2°.
  • Masaaki Kojima, Junnosuke Fujita
    1983 年 56 巻 1 号 p. 139-144
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Optically active trans(t-N,S)(t) and cis(t-N,S)(p) isomers of [Co{S(O)CH2CH2NH2}(tren)]2+ (tren=tris(2-aminoethyl)amine; t-N= tertiary amine nitrogen) were prepared, and their circular dichroism spectra were compared with those of Δ(S or R)- and Λ(S or R)-[Co{S(O)CH2CH2NH2}(en)2]2+ and two geometrical isomers of [Co(R-pn)(tren)]3+ (R-pn=(R)-1,2-propanediamine) and [Co(S-dmbn)(tren)]3+ (S-dmbn=(S)-3,3-dimethyl-1,2-butanediamine). Racemization or epimerization of these sulfenato complexes was studied in aqueous solutions with ionic strength of 1.0 (NaClO4) in the pH and temperature ranges of 3.65–8.8 and 24.0–40.0 °C, respectively. The rates of p- and t-isomers of the tren complex are proportional to concentrations of the complex, but independent of pH, the latter isomer accompanying some decomposition during the course of racemization. The first-order rate constants of the p- and t-isomers are 9.92×10−5 and ca. 1.2×10−6 s−1 at 30.0 °C, respectively. No epimerization takes place in the en complexes under the same experimental conditions. The difference in rate of racemization or epimerization of these sulfenato complexes seems to be related closely to the crowding around the S=O group of the complex.
  • Yoshikane Kawasaki, Yasushi Yamamoto, Masanori Wada
    1983 年 56 巻 1 号 p. 145-148
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Tris(cyclohexyl)hydroxoantimony(V) compounds, (C6H11)3Sb(OH)Y, Y=Cl, Br, CH3COO, and NO3, were prepared by the hydrolysis of μ-oxo-bis[tris(cyclohexyl)haloantimony(V)], [(C6H11)3SbX]2O, in a mixed solvent of acetone and water(7:3) or by a reaction of silver salts with [(C6H11)3SbX]2O in the same solvent. When Y=Cl and Br, the dehydration of the hydroxo compounds, giving the μ-oxo compounds, [(C6H11)3SbY]2O, occurred readily. However, when Y= CH3COO and NO3, the hydroxo form is stable. In the IR spectra of these hydroxo compounds in dichloromethane solution, the ν(O–H) band was observed at ca. 3630 cm−1 and the ν(Sb–O) band, at 565–513 cm−1. The hydrolysis of several μ-oxo compounds, [R3SbY]2O, R=CH3, C2H5, i-C3H7, C6H5, and p-CH3C6H4, Y=Cl, Br, CH3COO, and NO3, in a water-saturated dichloromethane solution was studied by using the IR spectra. All the compounds were hydolyzed in this solvent, but only the starting μ-oxo compounds were recovered from this solution.
  • Hisashi Okawa, Miyuki Kakimoto, Tatuo Izumitani, Masaaki Nakamura, Sig ...
    1983 年 56 巻 1 号 p. 149-152
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Strati-bis copper(II)–nickel(II) complexes, CuNi(R-sata) and CuNi(R-sacta) (R=H, 5-Me, 5-Br), have been prepared, where H4(R-sata) and H4(R-sacta) denote 1,2,3,4-tetrakis(R-salicylideneamino)-2,3-dimethylbutane and 1,2-bis(R-salicylideneamino)-1,2-bis(R-salicylideneaminomethyl)cyclohexane, respectively. ESR spectra of the complexes (frozen chloroform solution at liquid nitrogen temperature) showed a tetragonal pattern with a hyperfine coupling constant A⁄⁄ smaller than that of the relevant mononuclear copper(II) complex. Based on cyclic voltammetry and differential pulse polarography, it was shown that the Cu(II)→Cu(I) reduction occurs at a higher potential than that of the mononuclear reference complex. The ESR and electrochemical properties have been interpreted in terms of the stacking of the CuN2O2 and NiN2O2 planes and hence the electron delocalization over the whole molecule through the ligand π-system.
  • Ushio Sakaguchi, Ippei Yamamoto, Shinji Izumoto, Hayami Yoneda
    1983 年 56 巻 1 号 p. 153-156
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Ion-exchange chromatography on the IEX 220 anion-exchange resin has been used to measure the retention volumes of enantiomers of several complex anions when eluted by an aqueous solution of Δ-[Co(en)3]3+, Δ-[Co(sep)]3+, or Δ-[Co{(−)-chxn}3]3+, where en=ethylenediamine, sep=1,3,6,8,10,13,16,19-octaazabicyclo[6.6.6]eicosane, and chxn=trans-1,2-cyclohexanediamine. Comparison of these retention volumes suggests that chiral recognition in solution is effected along the C2 axis of [Co(en)3]3+, [Co(mal)2(en)], and [Co(ox)2-(en)], and along the C3 (or pseudo C3) axis of [Co(chxn)3]3+, [Co(edta)], [Co(tdta)], [Co(ox)2(gly)]2−, [Cr(mal)3]3−, and fac-[Co(β-ala)3], where mal=malonate, ox=oxalate, edta=ethylenediaminetetraacetate, tdta=1,4-butanediaminetetraacetate, gly=glycinate, and ala=alaninate. The mode of stereoselective association of these complex ions has been proposed.
  • Minahiro Okabayashi, Ken-ichi Okamoto, Hisahiko Einaga, Jinsai Hidaka
    1983 年 56 巻 1 号 p. 157-164
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Cobalt(III) complexes containing (2S,2′S)-1,1′-ethylenedipyrrolidine-2,2′-dicarboxylate (S,S-epro) and a bidentate ligand were prepared and characterized. The bidentate ligands were ethylenediamine, trimethylenediamine, oxalate, glycinate, (R)- or (S)-alaninate, (R)- or (S)-valinate, (R)- or (S)-prolinate, (R)- or (S)-pipecolate, sarcosinate, or N-ethylglycinate. The S,S-epro ligand coordinates stereoselectively to cobalt(III) ion to take only the Δ-sym configuration. The stereochemistry was discussed on the basis of the electronic absorption, CD, and 1H and 13C NMR spectra. The rate constants of isomerization and the Gibbs’ free energy difference (ca. 0.9 kJ mol−1) between the R(N) and S(N) isomers of the sarcosinato or N-ethylglycinato complex were investigated in relation to the interligand interaction. The thermodynamics and mechanisms of their isomerization process were little influenced by the N-alkyl groups.
  • Ken-ichi Okamoto, Katsuhiko Wakayama, Hisahiko Einaga, Shoichi Yamada, ...
    1983 年 56 巻 1 号 p. 165-170
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Three kinds of [Co(terdentate-N,O,S)2] type complexes were newly prepared; here terdentate-N,O,S denotes D-penicillaminate (D-pen), S-methyl-D-penicillaminate (D-smp) and S-methyl-L-cysteinate (L-smc). Each of the D-smp and L-smc complexes was chromatographically separated into three possible isomers; the D-pen complex was separated into two isomers. These isomers were characterized from their electronic absorption, CD and 1H NMR spectra. Two isomers isolated for [Co(D-pen)2] were assigned to trans(N) and trans(O), respectively, on the basis of the spectral behavior of the sulfur-to-metal charge transfer band and the reaction with dimethyl sulfate. Three isomers for [Co(D-smp)2]+ were derived from each of two isomers for [Co(D-pen)2]+ by the reaction with dimethyl sulfate. The electronic absorption and CD spectral behaviors are discussed in relation to the comparison of the thioether and thiolato type complexes.
  • Shinichi Inoue, Takuya Hori
    1983 年 56 巻 1 号 p. 171-174
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The reaction between thio-substituted cyclopropenium ions and sulfonium methylides gives unanticipated ketene derivatives. This reaction is supposed to proceed through an intermediate sulfonium salt formed from ylide addition to the cyclopropenyl ring.
  • Katsuhiro Saito, Hisashi Kojima, Tsuguo Okudaira, Kensuke Takahashi
    1983 年 56 巻 1 号 p. 175-179
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The reaction of 1-ethoxycarbonyl-1H-azepine with chlorosilane derivatives in HMPA in the presence of magnesium afforded the silanol derivatives, which upon heating gave the corresponding siloxane derivatives. In the same manner, tropone and 2,5-dimethyl-3,4-diphenylcyclopentadienone afforded the reduced dimers of them. However, tetraphenylcyclopentadienone and 2,5-dimethoxy-3,4-diphenylcyclopentadienone were reduced to the corresponding cyclopentenones under the reaction conditions. These reactions are considered to proceed via the corresponding radical anions which are formed by electron transfer from magnesium.
  • Mitsuo Komatsu, Jun-ichi Shibata, Yoshiki Ohshiro, Toshio Agawa
    1983 年 56 巻 1 号 p. 180-183
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Formation of 3,5-disubstituted 1,2,4-thiadiazoles by the reaction of sulfur dichloride with nitriles in the presence of a Lewis acid was found. For example, 3,5-diphenyl-1,2,4-thiadiazole was obtained with its chlorinated products, 3-o-chlorophenyl-5-phenyl- and 3-p-chlorophenyl-5-phenyl-1,2,4-thiadiazoles, from benzonitrile and sulfur dichloride using aluminium chloride as a catalyst (total yield 80%). The extent of chlorination of the aromatic ring was suppressed by use of iron(III) chloride as the catalyst or of sulfur chloride instead of the dichloride. Some substituted benzonitriles and pivalonitrile also gave thiadiazoles in lower yields.
  • Takaaki Horaguchi, Hidetaka Narita, Tsuneo Suzuki
    1983 年 56 巻 1 号 p. 184-187
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The reaction of ethyl (4-methoxy-8-oxo-5,6,7,8-tetrahydro-1-naphthyloxy)acetate and potassium hydroxide gave a mixture of 6-methoxy-4,5-dihydro-3H-naphtho[1,8-bc]furan and 6-methoxy-4,5-dihydro-3H-naphtho[1,8-bc]furan-2-carboxylic acid in total yield above 90%. The mechanisms of formation of two products were examined, and potassium 2a-hydroxy-6-methoxy-2a,3,4,5-tetrahydro-2H-naphtho[1,8-bc]furan-2-carboxylate was isolated as a precursor of 6-methoxy-4,5-dihydro-3H-naphtho[1,8-bc]furan. It has become apparent that strong bases such as sodium hydroxide, sodium ethoxide, and sodium hydride were also useful for syntheses of 6-methoxy-4,5-dihydro-3H-naphtho[1,8-bc]furan derivatives.
  • Shinkiti Koto, Naohiko Morishima, Yasuhiro Kihara, Hideko Suzuki, Shig ...
    1983 年 56 巻 1 号 p. 188-191
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The stereoselective synthesis of α-linked glucobiose derivatives using 6-O-acetyl- or 6-O-p-nitrobenzoyl-2,3,4-tri-O-benzyl-D-glucopyranose and a ternary mixture of p-nitrobenzenesulfonyl chloride, silver trifluorometh-anesulfonate, and triethylamine in dichloromethane is described.
  • Iwao Shimizu, Yoshio Kamei, Takeshi Tezuka, Taeko Izumi, Akira Kasahar ...
    1983 年 56 巻 1 号 p. 192-198
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Some ferrocenophanes, in which the two cyclopentadienyl rings are linked by biphenyl rings, have been synthesized via intramolecular reductive coupling of the corresponding formyl compounds with a low-valent titanium reagent. The structures of these cyclophane compounds were determined by IR, NMR, and UV spectra analyses. Transannular π-electronic interactions between the two biphenyl rings were examined on the basis of electronic spectra.
  • Masao Okubo, Tomoko Takahashi, K\={o}ji Koga
    1983 年 56 巻 1 号 p. 199-202
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Aryliminodimagnesium reagents (ArN(MgBr)2) condense with nitrosoarenes and nitroarenes giving the corresponding azoarenes and azoxyarenes, respectively. Azoxyarenes were moderately deoxygenated by treatment with excessive amounts of the reagent giving the corresponding azoarenes. The reaction of nitroarenes with differently substituted reagents afforded unsymmetrically substituted azoxy- and azoarenes: Small amounts of symmetrically substituted azoarenes, which originated from the oxidative coupling of the reagent molecules, were also isolated. The distribution of the three types of condensation products are governed by the electronic effect of substituents of both the reagents and the substrates.
  • Masao Okubo, K\={o}ji Koga
    1983 年 56 巻 1 号 p. 203-207
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    By use of the condensation reaction of aryliminodimagnesium reagents (ArN(MgBr)2) with nitroarenes, six symmetrical and eight unsymmetrical azoxyarenes including four pairs of isomers were prepared in 40–80% yields. The deoxygenation reaction of the azoxyarenes by treating with five molar equivalents of p-MeOC6H4N(MgBr)2 at 55 °C in tetrahydrofuran was also studied, and the reactivity of deoxygenation was correlated to the shift of the electronic absorption maximum of azoxyarene.
  • Mikio Hoshino, Kiyoshi Ikehara, Masashi Imamura, Yoshimasa Hama
    1983 年 56 巻 1 号 p. 208-211
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The absorption spectra of chlorophyll a in isopentane, 3-methylpentane, and methylcyclohexane solutions were studied over the temperature range 300–77 K. In those hydrocarbon solutions which were prepared using methanol treatment, chlorophyll a forms hydrated dimer at low temperatures. The dimer has an absorption peak at 695 nm at 160 K, which gradually shifts to 706 nm with decreasing temperature from 160 K to 77 K. The enthalpy change (–ΔH) for the formation of the dimer was obtained to be 41.0±0.8 kJ mol−1, independent of the solvent used. The entropy changes (–ΔS) were 113±8 J K−1 mol−1 for isopentane, 118±8 J K−1 mol−1 for 3-methylpentane and 128±8 J K−1 mol−1 for methylcyclohexane solutions. Comparative studies carried out of the solutions prepared without the methanol treatment suggest the existence of two kinds of hydrated monomeric chlorophyll a.
  • Hirokazu Maeda, Shigeo Furuyoshi, Yohji Nakatsuji, Mitsuo Okahara
    1983 年 56 巻 1 号 p. 212-218
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Monoaza crown ethers were prepared in satisfactory yields by the one-step reaction between diethanolamine or N,N-di[oligo(oxyethylene)]amines and oligoethylene glycol di(p-toluenesulfonates) or corresponding dichlorides in t-butyl alcohol/dioxane in the presence of sodium or potassium t-butoxide. The reaction conditions in the preparation of monoaza 15- and 18-crown ethers were studied. Various monoaza crown ethers having substituents were also prepared and their properties were investigated.
  • Mitsuji Yamashita, Nobuyoshi Suzuki, Manabu Yamada, Yukio Soeda, Hiroa ...
    1983 年 56 巻 1 号 p. 219-222
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Phosphide anions, prepared by an action of sodium dihydridobis(2-methoxyethanolato)aluminate on derivatives of phosphine, phosphine oxide, or phosphorus esters, react with primary and secondary alkyl halides to produce phosphine derivatives having a newly formed phosphorus-carbon bond. The reactivity increases in the order of chloride<bromide<iodide and of secondary<primary in alkyl halide. Reaction of phosphide anion is also feasible with p-toluenesulfonate. Reaction of an anion of diphenylphosphine oxide seems to proceed mainly as an SN2 type process.
  • Etsuo Niki, Yorihiro Yamamoto, Tsuneo Saito, Keiji Nagano, Seiichi Yok ...
    1983 年 56 巻 1 号 p. 223-228
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The rate and products of the ozonization of carboxylic acids, alcohols, and ketones have been studied in water at 30 °C. The ozonization of alcohols gave corresponding carbonyl compounds as major product. The ozonization of ketones brought about primarily the carbon-carbon bond cleavage and gave carboxylic acids. Saturated carboxylic acids such as acetic acid, propionic acid, and isobutyric acid were ozonized only slowly in neutral water, but they were ozonized faster in alkaline aqueous solution. On the other hand, α-hydroxy carboxylic acids such as glycolic acid and lactic acid were ozonized even in pure water. The mechanism of ozonization of these compounds and the effect of pH are discussed.
  • Jyunichi Tsuchiya, Etsuo Niki, Yoshio Kamiya
    1983 年 56 巻 1 号 p. 229-232
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    In order to study the inhibition of oxidation by vitamin E, the formation and reaction of chromanoxyl radicals and hindered phenoxyl radicals were examined by ESR. t-Butoxyl radical abstracted the phenolic hydrogens of α-, β-, γ-, and δ-tocopherols, 2,4,6-tri-t-butylphenol (TBP), and 2,6-di-t-butyl-4-methylphenol (BMP) to give corresponding phenoxyl radicals which were stable enough to be observed by ESR. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) also induced the formation of chromanoxyl and phenoxyl radicals. The ESR spectra of chromanoxyl radicals were recorded and their hyperfine coupling constants were determined. The phenoxyl radicals from TBP and BMP disappeared quite rapidly when excess t-butyl hydroperoxide was added, whereas α-chromanoxyl radical from α-tocopherol remained considerably. α-Chromanoxyl radical and phenoxyl radicals reacted with p-t-butylbenzenethiol to regenerate α-tocopherol and corresponding phenols respectively. The implications of these results are discussed.
  • Yukihisa Fujita, Yukinao Noda
    1983 年 56 巻 1 号 p. 233-237
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The thermal denaturation of lysozyme in aqueous solutions of N,N-dimethylformamide(DMF), N,N-dimethylacetamide(DMA), acetone, and dioxane at pH 3 was investigated by differential scanning calorimetry(DSC). The denaturation temperature, Td, decreased linearly with an increase in the concentration of organic solvent. The lowering in Td at identical concentrations of organic solvent increased in the order: acetone<DMF<DMA<dioxane. The calorimetric enthalpy of denaturation, ΔHd, showed a complex dependence on the solvent composition. For three organic solvents (not dioxane), the ΔHd first increased slightly with increasing the concentration of organic solvent and then started decreasing at different concentrations of each organic solvent. This behavior is analogous to those observed earlier with monohydric alcohols and with sulfoxides. For dioxane, on the other hand, the ΔHd decreased gradually with increasing the concentration of dioxane. The effect of these organic solvents on the thermal stability of lysozyme may correlate with their effect on the structure of water, which determines the strength of the hydrophobic interaction of the protein.
  • Sadao Arai, Yoshio Hashimoto, Nobuo Takayama, Takamichi Yamagishi, Mit ...
    1983 年 56 巻 1 号 p. 238-243
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    Although copper(I) is a more effective catalyst than copper(II) in the Ullmann condensation reaction of haloanthraquinones with ethylenediamine in aprotic solvents under a nitrogen atmosphere, the oxidation products of copper(I) by molecular oxygen enhanced the reaction rate compared to copper(I) catalyst. From the studies on the effect of Cu(II) salt addition to Cu(I) salt, solvent effects, and ESR spectra, it was concluded that alkoxycopper(II) species, formed by the oxidation of Cu(I) with molecular oxygen in alcohol–ethylenediamine solution, acted cooperatively with Cu(I) to increase the catalytic activity. The idea was also supported by the fact that the condensation was remarkably accelerated by the combination of Cu(I) and chloromethoxycopper(II). Reaction pathways including the alkoxo and halogen bridged Cu(I)···Cu(II) mixed valence complex are proposed and discussed.
  • Yoshinobu Inouye
    1983 年 56 巻 1 号 p. 244-247
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The geometry of N-benzyl-α-methoxycarbonylmethanimine N-oxide in the crystalline state was established to be Z by X-ray crystal analysis. The crystal was monoclinic, space group Pc, a=11.069(1), b=5.2335(7), c=8.620(1) Å, β=105.37(1)°, Z=2. The final R value was 0.037 for 1760 reflections.
  • Shigeru Oae, Norihiro Yamada, Ken Fujimori, Osamu Kikuchi
    1983 年 56 巻 1 号 p. 248-256
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The reactions of 4-methylbenzyl thiocyanate (1) with several nucleophiles have been investigated. Compound 1 possesses three electrophilic sites, i.e., benzylic carbon, sulfur and cyano carbon, to receive nucleophilic attack. PhS and CN which have HOMO’s of high energy levels appear to attack preferentially the sulfur atom. MeO was found to attack preferably the cyanide carbon, while amines which have HOMO’s of low energy levels prefer benzylic carbon to attack. The nucleophilic substitution on the sulfur or the cyanide carbon generates CN or p-xylene-α-thiolate anion, strong nucleophiles, as the primary products, which then initiate the complex secondary reactions. The selective reactivities of three attacking sites for nucleophiles in 1 have been rationalized in terms of MO theory.
  • Tatsuo Numata, Osamu Itoh, Toshiaki Yoshimura, Shigeru Oae
    1983 年 56 巻 1 号 p. 257-265
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    The Pummerer reaction of optically active cyanomethyl aryl sulfoxides with acetic anhydride gave the corresponding α-acetoxy sulfides which were induced with a partial asymmetry nearly 30% at α-carbon, while the 18O-label of the original sulfoxides was retained in more than 85% in the resulting ester, the Pummerer reaction product. Kinetic experiments with cyanomethyl (p-substituted phenyl) sulfoxides and α,α-dideuterated cyanomethyl p-tolyl sulfoxide in the reaction with acetic anhydride containing a small amount of acetic acid revealed that the rates were correlated with Hammett σ-values and ρ-value of −0.70 was obtained, while the kinetic isotope effect was practically nil, i.e., kHkD=1.01. These observations indicate clearly that the rearrangement is intramolecular and proceeds via forming a very intimate ion-pair and the rate-determining step is believed to be the S–O bond cleavage after the initial reversible acylation and deprotonation. Elimination of acetic acid proceeds through the Elcb type process. The uneven distribution of 18O in the two oxygens of the resulted ester, i.e., ether and carbonyl oxygens, suggests the recombination of the α-sulfenyl carbonium ion and acetate ion to be very rapid. The Pummerer reaction of optically active N,N-dimethyl-p-tolyl-sulfinylacetamide with excess acetic anhydride also gave the corresponding α-acetoxy sulfide in optically active form. In the presence of dicyclohexylcarbodiimide (DCC), the Pummerer reaction was found to be highly stereoselective affording the corresponding α-acetoxy sulfide with 65%e.e. Other optically active α-carbonyl-substituted alkyl sulfoxides, i.e., ethyl p-tolylsulfinylacetate and ω-(p-tolylsulfinyl)acetophenone also gave the corresponding highly optically active Pummerer rearrangement products in the treatment with acetic anhydride/DCC system. The Pummerer reaction of the 18O-labeled sulfoxides with acetic anhydride/DCC system gave the corresponding α-acetoxy sulfides which retained much of the original 18O-labels of the sulfoxides. These observations reveal clearly that in the Pummerer reaction of these compounds the acetoxyl migration is intramolecular and takes place through intimate ion-pairs.
  • Osamu Itoh, Tatsuo Numata, Toshiaki Yoshimura, Shigeru Oae
    1983 年 56 巻 1 号 p. 266-269
    発行日: 1983年
    公開日: 2006/06/27
    ジャーナル フリー
    In the Pummerer reactions of 18O-labeled benzyl, and 3,5-dichlorobenzyl p-tolyl sulfoxides with a large excess of unlabeled acetic anhydride in the presence of DCC as acid scavenger, the resulted Pummerer reaction products, the α-acetoxy sulfides, were found to have retained substantial amounts of 18O-label of the original sulfoxides, i.e., nearly a half or more. Meanwhile, when optically active benzyl, 3-chlorobenzyl, and 3,5-dichlorobenzyl p-tolyl sulfoxides were allowed to react with excess acetic anhydride in the presence of DCC, the α-acetoxy sulfides, the Pummerer reaction products obtained, were found to have no optical activity. These observations suggest that the acetoxyl migration from sulfur atom to α-carbon is predominantly intramolecular, however, the α-(p-tolylthio) carbenium acetate ion-pair formed during the reaction prior to racemization is less intimate than those which are formed in the reactions of cyanomethyl and (α-carbonyl-substituted methyl) p-tolyl sulfoxides which give the corresponding highly optically active α-acetoxy sulfides.
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