Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 66 , Issue 7
Showing 1-50 articles out of 51 articles from the selected issue
  • Farouk Rashwan, Hossnia Mohran
    1993 Volume 66 Issue 7 Pages 1871-1875
    Published: 1993
    Released: August 09, 2006
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    Cyclic and ac voltammetric studies of a 9,9′-bianthryl-10,10′-dicarbonitrile/tetrabutylammonium hexafluorophosphate system in superdry aprotic solvents are presented. The rate parameters were obtained for successive one-electron transfer reactions at a hanging mercury drop electrode (HMDE) and/or a Pt disk electrode. The results of electrode processes were found to be in agreement with the predictions of the Marcus theory for heterogeneous charge-transfer reactions. Quite rare behavior of the phase angle of the Faradaic fundamental alternating currect was observed and is discussed in detail.
  • Kichisuke Nishimoto
    1993 Volume 66 Issue 7 Pages 1876-1880
    Published: 1993
    Released: August 09, 2006
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    In order to obtain reasonable results for the π-electronic spectra of organic dyes with simple semi-empirical MO methods, a new approximation for the two-center electron repulsion integral (new gamma) is proposed which takes the chemical softness of the π-conjugated system into account. New gamma was successfully applied to PPP calculations of the electronic spectra of linear polyenes, simple cyanines, and simple merocyanines. The calculated results agree satisfactorily with the experimental data. On the contrary, a calculation based on the conventional PPP parameters gives shorter wavelengths for the absorption maxima of the electronic spectra of charge-resonance systems, such as cyanines and merocyanines. Furthermore, they give very strange electronic spectral shifts for merocyanines (see text), due to an inbalance between the one- and two-electron parts of the electronic transition energy.
  • Yasuhiro Yamane, Kazuo Miyaji, Kumi Hanafusa, Toshihiko Hanai, Hiroyuk ...
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1881-1885
    Published: 1993
    Released: August 09, 2006
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    The selectivity of phenyl methyl polysiloxane phases was examined from the structure-retention correlations of alkanes, alkanols, alkylbenzenes, chlorobenzenes, and polycyclic aromatic hydrocarbons. Selectivity R* was obtained from plots of van der Waals volume vs. the difference of their logarithm of capacity ratios, and enthalpy of these compounds was calculated from van’t Hoff plot. The enthalpy −ΔH of polycyclic aromatic hydrocarbons was greater on phenyl methyl phases compared to those obtained on 100% methyl polysiloxane phase. The retention time of homologue series of compounds can be predicted from the selectivity or enthalpy, but not for chlorinated benzenes due to the difficulty of the estimation of electron donner effect of chloro group.
  • Fulvio Corradini, Luigi Marcheselli, Lorenzo Tassi, Giuseppe Tosi
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1886-1891
    Published: 1993
    Released: August 09, 2006
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    Mixture kinematic viscosities (ν) were measured for the 1,2-ethanediol/1,4-dioxane binaries, covering the whole miscibility field (0 ≤ X1 ≤ 1), at 19 temperatures ranging from −10 to +80 °C. The experimental ν values were fitted by different equations, such as Grunberg–Nissan, McAllister, Auslander, Heric, and polynomial one, using pure component properties for the binaries studied. A comparison of the calculated and experimental data shows that all the selected equations can be safely employed to predict the dependence of ν on the composition and on the temperature of the system studied when no binary experimental data are available.
  • Masaharu Okazaki, Kazumi Toriyama
    1993 Volume 66 Issue 7 Pages 1892-1896
    Published: 1993
    Released: August 09, 2006
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    A pulse mode PYESR (Product-Yield-Detected ESR) spectrometer was developed by using an excimer laser and a TWT microwave amplifier as the components. The effect of ESR transition of the transient radical pair on the yield of the spin adduct of one of the component radicals was observed at a high microwave power of up to 16 W without microwave heating of the solvent. The spin adduct yield of the SDS radical in the photoreduction of anthraquinone in SDS micellar solution initiated by a laser pulse of 308 nm was modulated by up to 45% by a microwave pulse of 10 μs with a peak power of 16 W, which is resonant on the ESR transition of the transient anthrasemiquinone radical. The ESR spectrum of the radical pair was obtained by tracing this modulation as a function of the magnetic field, under which the photoreaction occurred. From the dependence of the product yield on the microwave pulse duration, we could obtain a time profile of the appearance of the transient radical pair.
  • Jingzhu Ren, Kazuhisa Sakakibara, Minoru Hirota
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1897-1902
    Published: 1993
    Released: August 09, 2006
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    Polymer-supported spin trap, poly[N-(p-vinylbenzylidene)-t-butylamine N-oxide] (polyPBN), was prepared by using p-chlorostyrene as a starting material, followed by Grignard reaction, condensation with t-butylamine, reduction, polymerization, and oxidation. The adsorption ability of NO2 by polyPBN was investigated in a closed-circulation system. PolyPBN maintains its original NO2 adsorbing ability in the mixed gas of nitrogen and nitrogen dioxide saturated with water vapor even after repeated (5 times) use. However, when the gaseous phase is freed from water, polyPBN exhibits less efficiency to adsorb NO2 and its adsorbing ability decreases gradually with the repeated use.
  • Hitoshi Kawashima, Tadamasa Shida
    1993 Volume 66 Issue 7 Pages 1903-1913
    Published: 1993
    Released: August 09, 2006
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    The possibility of stepwise amplification of molecular vibration by resonant multiple pulse excitation is theoretically considered on the basis of perturbation theory. A grating experiment favorable to its observation is proposed. It has proved that the effective interval of the repetitive irradiation to attain large amplitude vibrations is equal to odd halves of the period of the vibrational cycle and that there is no gain with an interval equal to the integral multiples of the vibrational period while such an interval is effective in mode selective excitation. It has also proved that the dispersed signal shifts periodically over a range of energy and that the range is widened as the vibrational amplitude is increased.
  • Takayoshi Shindo, Manabu Shindo, Hiroshi Ohnuma, Chizuko Kabuto
    1993 Volume 66 Issue 7 Pages 1914-1918
    Published: 1993
    Released: August 09, 2006
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    The crystal structure of 2,6-diethylnaphthalene thiourea adduct was solved by single crystal X-ray diffraction method. The crystal is monoclinic, space group P2l/c, with a = 12.571(3), b = 9.282(2), c = 14.634(3) Å, β = 92.14(2)°, V = 1706.3(6) Å3 and Z = 2. The final R value was 0.083. The structure was composed of thiourea (host) molecules enclosing channels with hexagonal-prism and 2,6-diethylnaphthalene (guest) molecules in the channels. The cross-section of the channel was deformed hexagon. In the channel, the occupying channel length of the guest molecule was 12.571(3) Å
  • Yasuo Kameda, Hiroki Saitoh, Osamu Uemura
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1919-1923
    Published: 1993
    Released: August 09, 2006
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    Time-of-flight neutron diffraction measurements have been carried out on 10 mol% NaNO3 solution in D2O. The isotopic substitution technique was applied to nitrogen atoms in the solution in order to determine both hydration structure around the nitrate ion, NO3, and intramolecular geometry of NO3 in the aqueous solution. It has become apparent that there exist 5.0 ± 0.5 water molecules coordinated to NO3 with the intermolecular distance r(N···D) = 2.80 Å. The intramolecular bond distance and the root mean square amplitude in NO3 have been determined to be rNO = 1.253 ± 0.006 Å and lNO = 0.058 ± 0.008 Å, respectively.
  • Ping Mu, Takuya Okada, Nakamasa Iwami, Yoshihisa Matsui
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1924-1928
    Published: 1993
    Released: August 09, 2006
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    The chemical shifts (δ) of some 1H NMR signals given by mono[6-(1-pyridinio)-6-deoxy]-α-cyclodextrin (1) in D2O were significantly changed by the addition of alkali salts of chaotropic anions such as Br, I, SCN, N3, NO3, and ClO4. However, only small changes in δ were brought about by the addition of alkali salts of antichaotropic anions such as F, Cl, SO42−, H2PO4, and HPO42−. The addition of the chaotropic anions caused a marked downfield shift in the signal of a C(5)–H located in the interior of the cavity of 1, and a marked upfield shift in the signal of one of the C(6)–H’s involved in the unsubstituted glucopyranose rings of 1. These facts indicate that the anions are included within the cavity and attract the pyridinio group of 1 close to the C(6)–H. The signal of the α-H’s in the pyridinio group showed a significant downfield shift with the addition of the alkali salts of Br, I, and SCN, which form charge-transfer complexes with 1.
  • Fudeko Tanaka, Yuzo Harada, Natsuko Todoroki, Makoto Aratono, Kinsi Mo ...
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1929-1933
    Published: 1993
    Released: August 09, 2006
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    The surface tension of the aqueous solution of anionic dye and nonionic surfactant mixture was measured as a function of total concentration at various compositions and at 298.15 K under atmospheric pressure. The dye used is sodium 4′-(butylamino)azobenzene-4-sulfonate (SBAS) and the nonionic surfactant is 2-(octylsulfinyl)ethanol (OSE). By use of thermodynamic relations developed previously, the phase diagrams of adsorption and micelle formation were constructed. It was found that SBAS and OSE are completely miscible with each other in the adsorbed film and that the adsorbed film is enriched in OSE compared with the solution except for a composition close to pure OSE. It was concluded that SBAS and OSE interact attractively with each other in the adsorbed and micellar states and, furthermore, that the interaction is more attractive in the micelle than in the adsorbed film. The miscibility of dye and nonionic surfactant is suggested to play an important role in the working of nonionic surfactant as a levelling agent in dyeing process.
  • Tsuyoshi Kawai, Seigo Nagame, Masahiro Nakazono, Katsumi Yoshino
    1993 Volume 66 Issue 7 Pages 1934-1937
    Published: 1993
    Released: August 09, 2006
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    The electrochemical polymerization of 1,4-bis(2-methylstyryl)benzene and the electrochemical behavior of the resulting polymer-modified electrode have been studied. The rapidly decreasing polymerization current of the 1,4-bis(2-methylstyryl)benzene can be attributed to the passivation effect of the resulting polymer coating. The polymer-modified electrode showed an electrochemical response in an aqueous electrolyte solution corresponding to solute electroactive ions. The electrochemical behavior was dependent on the polymerization charge and the size of the electroactive ions. The polymer-modified electrode is applicable as the selective electrode for electroactive ions and molecules in an electrolyte solution containing electroactive bacterial cells.
  • Kazutoshi Kobayashi, Atsuko Dochi, Hirofumi Yajima, Ryuichi Endo
    1993 Volume 66 Issue 7 Pages 1938-1943
    Published: 1993
    Released: August 09, 2006
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    The displacement adsorption behavior of a poly(methyl methacrylate) (PMMA) and polystyrene (PS) system onto a nonporous silica surface from a carbon tetrachloride solution was studied by utilizing the ESR method. The fractions of train segments for these polymers were determined from ESR spectra analyses; these values were compared with those of the individual adsorption. When PS was preadsorbed onto silica surface and PMMA solutions of various concentrations were added, the amount of PS desorbed from silica surface was proportional to an increase in the initial concentration of the PMMA solution; at the final concentration, PS was completely replaced by PMMA. This phenomenon was due to the stronger interaction of PMMA with the silica surface arising from its polar character, and the greater hydrogen bonding ability. The amount of adsorption for PMMA, which saturated the silica surface, was lower than that when adsorbed on silica surface individually. The adsorbed PMMA formed a more compressed polymer layer compared with that for the case in which PMMA was adsorbed alone. The amount and conformation of the adsorbed PMMA were affected by the presence of PS in the solution.
  • Takayuki Fueno, Shin-ya Takane
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1944-1948
    Published: 1993
    Released: August 09, 2006
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    Reaction of the hydrogen atom with hydrazoic acid HN3 in the gas phase has been investigated theoreticallly. Tracing of the reaction path by the SCF procedure based on the 6-31G (d,p) basis functions has shown that the reaction proceeds through an initial rate-determining hydrogen atom addition to HN3 giving a doublet radical H2N3, which is subsequently self-decomposed into NH2 + N2. The barrier height for the initial addition step calculated by the MRD-CI method employing the [4s2p1d] basis sets is 21 kJ mol−1 (with the vibrational zero-point energy correction). The bimolecular rate constants for the overall reaction calculated by the conventional transition state theory combined with appropriate tunneling corrections are found to agree well with the experimental data reported over the temperature range 300 to 500 K.
  • Shigeki Matsumiya, Akira Izuoka, Tadashi Sugawara, Tomohiro Taruishi, ...
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1949-1954
    Published: 1993
    Released: August 09, 2006
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    Radical ion salts of both chiral (R,R) and racemic organic donor, (Me2ET)2X (Me2ET = trans-dimethylbis(ethylenedithio)tetrathiafulvalene, X = PF6, ClO4, and ReO4) were electrochemically prepared and their crystal structures were analyzed. The donor molecules are stacked in a twist-type column to reduce steric repulsion caused by methyl groups. The anions are contained in the cavities formed both by methylated and unsubstituted ethylene groups of the donor molecules, and their orientation is fixed through hydrogen bonds to methine and methylene protons. The structural difference between chiral and racemic salts is discussed. In spite of the difference in the crystal structure, their conductivity is almost identical, reflecting similarity of side-by-side S–S contacts between the donor molecules.
  • Jun-ichi Aihara, Haruo Hosoya
    1993 Volume 66 Issue 7 Pages 1955-1958
    Published: 1993
    Released: August 09, 2006
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    The topological resonance energies (TREs) indicate that mono- to hexaanions of C60 are as aromatic as the neutral species. The tendency of multiply charged C60 anions to retain their own spherical conjugated systems can be attributed to aromatic character. Tetraanions of C28, C36, and C44 are likewise predicted to be highly aromatic. Thus, the formation of metallofullerenes, such as U@C28, U@C36, and U@C44, can be rationalized in terms of aromaticities of the ligands.
  • Hidenori Ikezawa, Masashi Takahashi, Masuo Takeda, Yasuo Ito
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1959-1962
    Published: 1993
    Released: August 09, 2006
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    The 127I Mössbauer spectra have been obtained at 20 K for the diphenyliodonium halides, Ph2IX (X = Cl, Br) and their derivatives, (p-R–C6H4) IPhBr (R = CH3, CH3O, Cl, COOH and NO2). The valence electron populations of iodine are determined by the interactions with carbon atoms but not with bridging halogen atoms. The iodine–carbon bonds, having large p-character, are affected scarcely by the substituents at the para-position of the phenyl group. The large ηvalues for those compounds are explained in terms of a lone pair electrons on iodine(III) atoms.
  • K. Kowalczyk, Y. Parent, G. Palavit
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1963-1966
    Published: 1993
    Released: August 09, 2006
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    Phosphorodiamidic acid disappears when it is heated at 110 °C. It condenses, giving the ammonium salt of P,P′-diamidoimidodiphosphoric acid. The value of the enthalpy for this reaction is −3.6 kJ mol−1. We determined the apparent activation energy for the condensation reaction by two different methods: -Differential Scanning Calorimetry, -Measuring out ammonium. We obtained by these two methods the same apparent activation energy: 120 kJ mol−1.
  • Wenzhi Hu, Hiroki Haraguchi
    1993 Volume 66 Issue 7 Pages 1967-1970
    Published: 1993
    Released: August 09, 2006
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    A novel method for enantiometric separation using an ODS stationary phase coated with bile salt micelles in high-performance liquid chromatography has been developed, where bile salt surfactants such as sodium cholate and sodium deoxycholate were used for micelle formation. The present method was applied to the separation of the enantiomers of 1,1′-binaphthyl-2,2′-diyl hydrogenphosphate (BNDHP) and N-dansylphenylalanine by using acetonitrile–water solution as the mobile phase. The dependence of the capacity factors and separation factors on the acetonitrile concentration in the mobile phase was examined for BNDHP enantiomers. These factors decreased with increasing acetonitrile concentration, which resulted in the change of separation characteristics of BNDHP enantiomers. Although BNDHP and N-dansylphenylalanine enantiomers were separated, similar enantiomers such as 2,2′-dihydroxy-1,1′ -binaphthyl and other N-dansylamino acids were not separated in the present separation system.
  • Kaoru Ogura, Sorin Kihara, Shigeo Umetani, Masakazu Matsui
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1971-1978
    Published: 1993
    Released: August 09, 2006
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    The transfer of alkali metal and alkaline earth metal ions (Mz) from aqueous to nitrobenzene (NB) phases, facilitated by mono-, bi-, or tridentate phosphine oxides (PO), was investigated in terms of the voltammetry for the ion transfer across the interface of two immiscible electrolyte solutions. The complex formation of Mz with PO in the vicinity of the interface and the transfer process of Mz were clarified based on an analysis of the current-potential curves, while referring to information obtained from the synergistic ion-pair extraction of Mz(ClO4)z with PO. The stability constants of Mz–PO complexes in NB were evaluated based on the half-wave potentials in the ion transfer voltammograms, and were related to the properties of Mz and PO.
  • Mannar R. Maurya, Changaramponnath Gopinathan
    1993 Volume 66 Issue 7 Pages 1979-1983
    Published: 1993
    Released: August 09, 2006
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    Syntheses of dinitrosylmolybdenum(0) complexes of Schiff bases derived from salicylaldehyde, 5-chlorosalicylaldehyde, o-hydroxyacetophenone, and p-nitrobenzoylhydrazide have been carried out in one step by the reaction of [Mo(acac)2(NO)2] (acacH = acetylacetone) and the Schiff bases. The complexes are of the type [Mo(LH)2(NO)2] (LH2 = Schiff base) in which Schiff bases behave as monobasic bidentate ligands and coordinate to molybdenum through the azomethine nitrogen and enolic oxygen of the hydrazide moiety after deprotonation. Two geometrical isomers with nitrosyl groups trans to each other have been noticed in solution. Dioxomolybdenum(VI) complexes of the above Schiff bases have also been synthesized using [MoO2(acac)2] as precursor for comparison.
  • Takeshi Yamamura, Makoto Tadokoro, Koji Tanaka, Reiko Kuroda
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1984-1990
    Published: 1993
    Released: August 09, 2006
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    The syntheses, structures, absorption spectra, and redox potentials of Ni(tsalen), H2tsalen = N,N′-bis(o-mercaptobenzyliden)ethylenediamine, and Ni(ebmba), H2ebmba = N,N′-bis(o-mercaptobenzyl)ethylenediamine, are described. Ni(tsalen) was prepared directly from N,N′-bis(o-t-buthylthiobenzyliden)ethylenediamine, from which H2ebmba and, subsequently, Ni(ebmba) were also prepared. The crystal data for these two complexes are as follows: 1) Ni(tsalen); space group Pna21 with the unit-cell dimensions a = 8.929(1), b = 22.603(2), c = 7.484(1) Å, Z = 4, 2) Ni(ebmba); space group P21/c, a = 13.324(5), b = 7.9263(8), c = 15.262(3) Å, β = 101.23(2)°. Ni(tsalen) and Ni(ebmba) adopt squareplanar geometries with average Ni–S distances of 2.157 and 2.165 Å, respectively. The Ni–N distances of these complexes are 1.85(5) and 1.945 Å, respectively. These values, as well as the redox potentials and absorption maxima, ware compared with those of another type of NiS2N2 compound, [Ni(ebtsa)]2−; H4ebtsa = N,N′-bis(o-mercaptobenzoyl)ethlenediamide.
  • Naomi Odano, Kazumasa Harada, Akio Urushiyama
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 1991-1997
    Published: 1993
    Released: August 09, 2006
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    The title dicyano-complex of Rh(III) was newly synthesized. Stepwise ligand substitutions in an aqueous medium through trans-[RhCl2(tn)2]+, trans-[Rh(SO3)2(tn)2], trans-[Rh(CN)(SO3)(tn)2], and trans-[Rh(CN)Cl(tn)2] were studied. The final substitution of Cl of trans-[Rh(CN)Cl(tn)2] by CN was effected in a mixed medium of DMSO, ethanol, and H2O (8 : 1 : 1). The ligand field tetragonal parameters of Dt ca. −380 cm−1 were estimated based on the lower d–d absorption maximum at 36100 cm−1. The sharp IR peaks of ν (C≡N) were observed at 2115 cm−1 (nitrate) and 2116, 2131 cm−1 (perchlorate). The slight splitting detected for solid compound of the perchlorate was attributed to the presence of a structurally different complex species with respect to the Rh–C≡N bondings in the crystal. The X-ray crystal data are: trans-[Rh(CN)2(tn)2](NO3): monoclinic, space group P21/n, a = 11.626(4), b = 6.3624(6), c = 10.026(3) Å, β = 113.54(4)°, Dm = 1.78, Dc = 1.784 g cm−3, Z = 2; trans-[Rh(CN)2(tn)2](ClO4): triclinic, space group , a = 9.230(5), b = 12.690(3), c = 6.861(2) Å, α = 101.36(3)°, β = 106.10(3)°, γ = 76.42(3)°, Dm = 1.80, Dc = 1.800 g cm−3, Z = 2. In these two crystal lattices, the trans-[Rh(CN)2(tn)2]+ cations occupy the special positions of the inversion center, and the Rh-tn six-membered chelate rings appear in the chair form. While all of the bond distances and angles were well conserved, an appreciable variation appeared in the dihedral angles defined in the chair chelate rings (N–Rh–N : N–C···N–C and N–C···N–C : C–C–C). This structural variation in the Rh-tn chelate rings is responsible for the complicated splittings of the IR bands of the perchlorate, especially, in the CH2 rocking region of 880—970 cm−1. Other important geometrical data of the complex are (in mean values): Rh–N = 2.09, Rh–C = 2.03 Å, N–Rh–N (in chelate ring) = 91.8°
  • Fumio Ando, Ryosuke Mio, Jugo Koketsu
    1993 Volume 66 Issue 7 Pages 1998-2001
    Published: 1993
    Released: August 09, 2006
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    (Dialkylamino)dimethylarsines, (dimethylamino)diphenylarsine, and (dialkylamino)dimethylstibines react with diketene to yield N,N-dialkyl-4-dimethylarsino-3-oxobutanamides, N,N-dimethyl-4-diphenylarsino-3-oxobutanamide, and N,N-dialkyl-4-dimethylstibino-3-oxobutanamides, respectively. These group 15 metalloid-substituted 3-oxobutanamides exist as keto-enol tautomers and the keto isomers are predominant in solution or in neat state. This reaction is the first example of 1,4-addition of heteroatom-nitrogen bond to diketene.
  • Masatoshi Kawashima, Reiko Hirata
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2002-2005
    Published: 1993
    Released: August 09, 2006
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    Optical resolution of 2,2′-dihydroxy-1,1′-binaphthyl (1) with (R,R)-1,2-cyclohexanediamine (2) in toluene yielded optically pure (R)-1 in a yield of 160% based on the theoretical amount of the enantiomer contained in the racemate by selective crystallization of a less soluble complex, (R)-1·(R,R)-2, and epimerization of more soluble complex, (S)-1·(R,R)-2. Also optically pure (S)-1 was obtained with the same enantiomer of the resolving agent, (R,R)-2, in a yield of 154%. (R,R)-1,2-Diphenyl-1,2-ethanediamine (3) was a suitable resolving agent for both 1 and 6,6′-dibromo-2,2′-dihydroxy-1,1′-binaphthyl. Kinetic study indicated that the reversible first-order rate constants for the epimerizations of (S)-1·(R,R)-2 and (S)-1·(R,R)-3 were larger than that for the racemization of (S)-1. The activation energy and frequency factor for the epimerization of (S)-1·(R,R)-2 were 109 kJ mol−1 K−1 and 3 × 1010 s−1, respectively, and those for (S)-1·(R,R)-3 were 96 kJ mol−1 K−1 and 1 × 108 s−1, while those for the racemization of (S)-1 were 85 kJ mol−1 K−1 and 9 × 105 s−1, respectively.
  • Jin-Shik Lee, Yuka Murakawa, Akira Hanami, Mitsuaki Narita
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2006-2010
    Published: 1993
    Released: August 09, 2006
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    The influence of unnatural amino acid residues, i.e., β-alanine (β-Ala) and 4-aminobutyric acid (γ-Aba) residues, on the solubility of peptides containing them was studied in organic solvents. The difference between the solubilities of peptides containing β-Ala, γ-Aba, Pro, Gly, Leu, and Asp(OBzl) was investigated by the solvent titration method by use of IR absorption spectra. The order of their solubilities is as follows, peptides containing Pro > β–Ala > γ–Aba > Asp(OBzl) > Leu > Gly. The extreme high solubility of peptides containing Pro residues is explained by the concept of “Peptide Segment Separation” caused by the tertiary peptide bond of the Pro residue. The high solubility of peptides containing β-Ala or γ-Aba residues is believed to be due to the difference of the geometries of the Gly, β-Ala, and γ-Aba residues. Their effective concentration seemed to be less important than their geometry. The role of β-Ala and γ-Aba residues in the solubility of peptides is similar to the role of Pro residues rather than Asp(OBzl), Gly, and Leu residues.
  • Ahmed M. M. El-Saghier
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2011-2015
    Published: 1993
    Released: August 09, 2006
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    A variety of thieno[2,3-b]thiophenes were prepared under phase-transfer catalysis conditions. The reaction of diethyl 3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylate with hydrazine hydrate gave the corresponding hydrazide derivative which was also subjected to react with acetylacetone, ethyl acetoacetate, malononitrile, CS2, phenyl isothiocyanate, p-chlorobenzaldehyde and diazotization to afford the described compounds. Treatment of 2,5-bis(azidocarbonyl)-3,4-dimethylthieno[2,3-b]thiophene with ethyl cyanoacetate, diethyl malonate or malononitrile gave the corresponding triazole derivatives.
  • Katsumi Higuchi, Makoto Onaka, Yusuke Izumi
    1993 Volume 66 Issue 7 Pages 2016-2032
    Published: 1993
    Released: August 09, 2006
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    A new attempt was investigated to utilize inorganic solid acids and bases for the promotion of the reaction of cyanotrimethylsilane (Me3SiCN) with carbonyl compounds. Strongly acidic solids, such as Sn4+ ion-exchanged montmorillonite (Sn-Mont) and Fe3+ ion-exchanged montmorillonite (Fe-Mont), as well as basic solids, such as calcium fluoride (CaF2), hydroxyapatite (HAp), calcium oxide (CaO), and magnesium oxide (MgO), catalyzed the reaction of Me3SiCN with aldehydes and ketones to afford the corresponding 2-(trimethylsiloxy)alkanenitriles in good yields. The reactions of dimethyl acetals with Me3SiCN in the presence of solid acids afforded 2-methoxyalkanenitriles. In cyanosilylations of α,β-unsaturated ketones two kinds of adducts were produced selectively, depending on the use of a solid acid or a solid base: 1,4-Adducts (trimethylsilyl enol ether forms) were selectively obtained in the presence of strong solid acids, such as Fe-Mont and Sn-Mont, while 1,2-adducts (trimethylsilyl ether forms) were predominantly formed in the presence of solid bases, such as HAp, CaO, and MgO. The solid acids and bases realized higher activities and selectivities in the cyanosilylation than did conventional homogeneous catalysts.
  • Tetsuo Otsubo, Yasuhiro Kono, Norio Hozo, Hisakazu Miyamoto, Yoshio As ...
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2033-2041
    Published: 1993
    Released: August 09, 2006
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    The title heteroarene (TBD) isoelectronic with perylene was synthesized by way of a dimerization of thieno[2,3-b]thiophene. In addition, 1,4,5,8-tetramethyl, tetraethyl, tetrakis (methylthio), and tetrakis (ethylthio) derivatives were readily obtained from TBD. An X-ray crystallographic analysis of TBD demonstrated that the molecular structure is quite planar and symmetrical, but strained in the bond angles. The crystal structure comprises herringbone-type column stacking with intercolumnar heteroatomic interactions. TBD showed the same oxidation potential as did perylene, and like perylene, formed an iodine complex with a relatively high electrical conductivity of 0.11 S cm−1. On the other hand, all of the TBD derivatives gave poorly conductive iodine complexes. In addition, TBD and the derivatives formed charge-transfer complexes with strong electron acceptors, such as 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (TCNQF4), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), and 1,1,2,3,4,4-hexacyano-1,3-butadiene (HCBD). These π-complexes, however, were mostly of low conductivity. The electrolyses of TBP gave powdery conductive polymers, whereas those of tetrakis (methylthio) TBD gave crystalline radical cation salts with conductivities of the order of 10−3 S cm−1.
  • Yoshihiko Watanabe, Yoshio Ueno, Takeshi Toru
    1993 Volume 66 Issue 7 Pages 2042-2047
    Published: 1993
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    Treatment of vinyl- and (5-oxo-1-cyclopentenyl)selenonium tetrafluoroborates 2 and 4 with a variety of carbanions gives cyclopropane derivatives 3 and 5 in good yields. The reaction of vinylselenonium salt 2 with sodium alkoxides in the presence of aldehydes gives various kinds of glycidyl ethers 7 in excellent yields. The reaction of 2 with hydroxyacetone in the presence of K2CO3 affords cyclized products 8 and 9 together with the Michael addition product 10.
  • Chung-gi Shin, Masashi Seki, Takeshi Kakusho, Nobuyuki Takahashi
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2048-2053
    Published: 1993
    Released: August 09, 2006
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    Novel enzymatic syntheses of various dehydrodipeptides by the coupling of α,γ-dimethyl N-benzyloxycarbonyl(Z)-α-dehydroglutamate [Cbz–ΔGlu(OMe)–OMe; 1] with α-amino acid amides (H–AA–NHR) using proteases, such as papain and α-chymotrypsin A (CT), are described. It was found that there was conspicuous difference between the catalytic actions of papain and CT toward 1. In the case of papain, the selective coupling of α-ester of 1 with H–AA–NHR took place to give Cbz–ΔGlu(OMe)–AA–NHR, while in the case of CT the coupling of γ-ester of 1 proceeded predominantly to give Cbz–ΔGlu(AA–NHR)–OMe. The present study suggests that both papain and CT may become a versatile tool for the organic synthesis by the coupling of not only ΔGlu derivatives but also the other α-dehydroamino acids with α-amino acids or peptides.
  • Tetsuyuki Saika, Tomokazu Iyoda, Takeo Shimidzu
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2054-2060
    Published: 1993
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    Six bis(4-cyano-1-pyridinio) derivatives have been synthesized and deposited onto electrodes by cathodic electropolymerization (ERed = −0.64 — −0.74 V vs. SCE) under basic conditions. The deposited films were constructed of polyviologens that showed characteristic electrochromisms with colorless or slightly yellow to blue- or red-violet. The derivative was reduced to 4-cyano-1,4-dihydro-4-pyridyl radicals, which were coupled successively to form a polyviologen film on the electrode with an elimination of cyanide ions. Characteristically, the polyviologen films deposited by this electropolymerization were insoluble in water and common organic solvents with a spontaneous cross-linking. Especially, a polyanion as a supporting electrolyte forced the polyviologen to form a polyelectrolyte complex in situ. The current efficiency of surface coverage with the polyanion electrolyte (23% in the typical case) was about four-times larger than those with monomeric anions.
  • Yoko Mori, Naohiko Morishima
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2061-2067
    Published: 1993
    Released: August 09, 2006
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    Reductive ring-opening reactions of the 4,6-O-benzylidene derivatives of methyl 3-deoxy-β-D-arabino-, 3-deoxy-α-D-ribo-, and 2-O-benzyl-3-deoxy-α-D-ribo-hexopyranosides with LiAlH4 and AlCl3 in the molar ratio of 4 : 4 gave the 4- and 6-O-benzyl derivatives in a ratio of 7 : 3. The product ratios for the reactions of methyl 4,6-O-benzylidene-2,3-dideoxy-2-fluoro-α-D-arabino- and β-D-ribo-hexopyranosides and methyl 2-O-benzyl-4,6-O-benzylidene-3-deoxy-3-fluoro-α-D-gluco- and β-D-allopyranosides were 3 : 2, 2 : 3, 1 : 1, and 3 : 7, respectively. When the molar ratio of the reagents was 2 : 4, however, the product ratios for the reactions of all the above-mentioned 4,6-O-benzylidene derivatives were approximately equal to 4 : 1. The influence of fluorine at C-2 or C-3, as well as that of the molar ratios of LiAlH4 and AlCl3, on the regioselectivity of the reductive cleavage of 4,6-O-benzylidenehexopyranosides are discussed.
  • Tomohiro Nigo, Takeshi Hasegawa, Yoshiyuki Kuwatani, Ikuo Ueda
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2068-2072
    Published: 1993
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    The Diels-Alder dimerization of 2-bromo-2,4-cyclopentadienone ethylene acetal (2) gave endo-2,7-dibromodicyclopentadiene-1,8-dione 1,8-bis (ethylene acetal) (3) as a minor product in a 4.5% yield. Ultraviolet irradiation of 5 led to dimerization product 7. Deacetalization was accomplished by treating with concentrated sulfuric acid to give 1,5-dibromopentacyclo[5.3.0.02,5.03,9.04,8]decane-6,10-dione (9). Compound 9 was converted into a new cage system, 10-oxa-9-oxopentacyclo[5.3.0.02,4.03,6.05,8]decane, in a high yield by treating with 5% aqueous potassium hydroxide at 80 °C.
  • Wei-Hsien Wang, Pai-Hui Cheng, Hsing-Ching Hsieh
    1993 Volume 66 Issue 7 Pages 2073-2076
    Published: 1993
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    The kinetics of acid-catalyzed proton exchange in a series of thiolactams (5- to 7-membered ring) and N-methylthioacetamide were studied. Kinetic data were observed by NMR line-broadening and computer simulation methods. The second-order rate constants of all the thiolactams and N-methylthioacetamide are within the same order of magnitude. It is concluded that the imidic acid mechanism is dominant in thiolactams and N-methylthioacetamide.
  • Shinro Yasui, Kosei Shioji, Masakuni Yoshihara, Toshihisa Maeshima, At ...
    1993 Volume 66 Issue 7 Pages 2077-2083
    Published: 1993
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    Alkyl diphenylphosphinites (1) react rapidly with 10-methylacridinium iodide (2a) to afford the corresponding phosphonium ions (3), which gradually decompose to phosphine oxide, the expected Arbuzov product. Large difference in the rate of the first (phosphonium-forming) and the second (phosphonium-decomposing) steps enables us independent kinetic investigation for both steps, with which it has been found that the first step obeys second-order kinetics with first-order with respect to 1 and 2a, respectively. The second step proceeds according to either the SN2 mechanism when alkyl substituent in 1 is primary or secondary, in which iodide ion acts as a nucleophile, or the SN1 mechanism when the substituent is tertiary. Closer examination on the first step with activation parameters reveals that the transition state of this step becomes more reactant-like as the substituent in 1 becomes bulkier. For the second step, survey of the activation parameters shows that the breaking of the carbon–oxygen bond in 3 predominates over the formation of the oxygen–phosphorus double bond.
  • Ping Mu, Masahiko Fujie, Yoshihisa Matsui
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2084-2087
    Published: 1993
    Released: August 09, 2006
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    Mono[6-(1-pyridinio)-6-deoxy]-α-cyclodextrin and its analogs exchanged the α-hydrogens of their pyridinio moieties with the deuteriums of solvent D2O in an alkaline buffer solution via the formation of the pyridinium ylide intermediates. The H/D exchange reaction was facilitated by the hydrophobic cavity of cyclodextrin, as well as by a substitution of the additional pyridinio group for the primary OH group, especially in the adjacent glucopyranose moiety of the cyclodextrin residue. On the other hand, the reaction was moderately retarded by an increase in the ionic strength of the solution, and markedly retarded by inorganic anions, such as I, SCN, and ClO4, which were strongly bound to the cavity of cyclodextrin.
  • Shinji Toyota, Masahiko Endo, Mitsuru Teruhi, Yoshiyuki Noda, Michinor ...
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2088-2096
    Published: 1993
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    Sterically compressed title compounds which carry a five-membered ring condensed to the triptycene skeleton were synthesized by the Diels-Alder reaction of 1,1-dimethyl-1,2-dihydroaceanthrylene with a benzyne. The structures of three compounds were determined by X-ray crystallography. The molecules have several abnormal bond lengths and angles in addition to significant deformation of the benzene rings as well as the triptycene skeleton to avoid the eclipsed conformation about C(1)–C(10b) and C(1)–C(2) bonds. The effects of the substituents at the 7—10 positions are rather small, but an interesting bond angle deformation is found on comparison of the C(10a)–C(10)–substituent bond angles. Molecular mechanics calculation was performed for the dimethoxy compound to compare the calculated structure with the X-ray structure. Molecular flexibility of the unsubstituted compound was discussed on the basis of MM2 calculation.
  • Kiyoshi Yamauchi, Katsuya Togawa, Masayoshi Kinoshita
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2097-2100
    Published: 1993
    Released: August 09, 2006
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    1,2-Bis(dihydrophytyl)glycero-3-phosphate (DPhyPA) was synthesized as an analog of archaebacterial lipids. Upon sonicating in amine-containing buffers like 0.05 M Tris–HCl (pH 7.8), the lipid gave rise to the stable liposomal assemblies, which could store 5(6)-carboxyfluorescein at high temperature as high as 70 °C in the interior. The assembly also had a large negative zeta-potential and showed an absence of gel-to-liquid crystalline phase transition from −20 to 80 °C. A Langmuir monolayer at an air/water interface suggested that the maximum molecular area of the lipid was 0.9—1.0 nm2. These properties were compared with the assemblies prepared from conventional 1,2-dipalmitoyl-sn-glycero-3-phosphate and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine.
  • N. Sukumar, M. N. Ponnuswamy, R. Jayakumar
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2101-2103
    Published: 1993
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    An X-ray crystal structure analysis of the title compound (C14H22N2O6) was carried out. There are two molecules (A & B) in the asymmetric unit. In both molecules valine side chains exist in a staggered conformation. The molecules in the crystalline state are stabilized by N–H···O and C–H···O hydrogen bonding.
  • Hiroshi Kawamoto, Ryo Yokoyama, Kin-ichi Tsunoda, Hideo Akaiwa
    1993 Volume 66 Issue 7 Pages 2104-2105
    Published: 1993
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    Hourly variation of the lability of soluble copper(II) complex in water samples from the Kiryu River in Gunma prefecture was investigated. By considering the relationship between the lability of soluble copper(II) complexes and the copper(II) complexing capacity, the lability was found to reflect the presence of weak CuII complexes.
  • Masahiro Mikuriya, Koshiro Toriumi
    1993 Volume 66 Issue 7 Pages 2106-2108
    Published: 1993
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    The crystal structure of {2-[2-(dimethylamino)ethylthio]ethanolato}isothiocyanatocopper(II) at 210 K was determined by the single-crystal X-ray diffraction method. The unusual magnetic property was examined in terms of the temperature dependence of the magnetic susceptibility (85—290 K) and a differential scanning calorimetric analysis.
  • Kiyohiko Nakajima, Masaaki Kojima
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2109-2111
    Published: 1993
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    The title complex was synthesized and the structure was determined by the X-ray method. The oxygen atoms of the (1R,2S)-norephedrine moieties do not coordinate to manganese and the coordination polyhedron is a distorted trigonal bipyramid. The steric interactions between the bound bromide ions and the methyl and phenyl groups of the (1R,2S)-norephedrine moieties are suggested to influence the structure of the complex.
  • Yasuo Nakao, Yasuko Oohata, Rika Fujiwara, Masumi Itadani, Takeshi Sak ...
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2112-2114
    Published: 1993
    Released: August 09, 2006
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    The dinuclear copper(II) complexes of HL-Et or HL-Me and a bridging ligand (X (X = N3, NCS, NCO, OH, OAc, (CH3)3CCOO (OPi), o-C6H4 (CH3)COO (OTo), pyrazolate (Pz), and imidazolate (Im))) have been prepared and characterized, where HL-Et = N,N,N′,N′-tetrakis[(1-ethyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane and HL-Me = N,N,N′,N′-tetrakis[(1-methyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane. The magnetic moments of these complexes differ depending upon their bridging groups. The electrochemistry in N,N-dimethylformamide showed that only one-electron reduction(Cu2+–Cu2+ → Cu+–Cu2+) can occur for the dinuclear complexes bridged by X = N3, OAc, OPi, OTo, Pz, whilst the other complexes showed irreversible processes.
  • Jiro Toyoda, Akio Oda, Ichiro Murata, Atsushi Kawamoto, Jiro Tanaka, K ...
    1993 Volume 66 Issue 7 Pages 2115-2117
    Published: 1993
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    The charge-transfer complex of 2,7-bis(methylthio)-1,6-dithiapyrene (MTDTPY) with tetracyano-2,6-naphthoquinodimethane (TNAP) showed an alternated stacking mode of crystal structure. There are no short intermolecular contacts. The ionicity was estimated to be neutral based on an analysis of the IR stretching frequency of the CN groups and the transition energy of the charge-transfer band.
  • Takao Tokumitsu, Satomi Nagao
    1993 Volume 66 Issue 7 Pages 2118-2120
    Published: 1993
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    1,1-Diamino-2-nitroethylenes reacted with dimethyl acetylenedicarboxylate (2) to give an electrophilic adduct (dimethyl 2-[(2-imidazolidinylidene)nitromethyl]-2-butenedioate) as well as cyclocondensation products derived from the electrophilic adducts. The reaction of 1,1-dimorpholino-2-nitroethylene with 2 afforded dimethyl 2-(2,2-dimorpholino-1-nitroethenyl)-2-butenedioate or dimethyl 2-(dimorpholinomethylene)-3-(nitroethylene)butanedioate derived from the [2+2] cycloadduct.
  • Tetsuya Satoh, Kenji Itoh, Masahiro Miura, Masakatsu Nomura
    1993 Volume 66 Issue 7 Pages 2121-2123
    Published: 1993
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    Iodination of naphthalenesulfonyl chlorides accompanied by desulfonylation efficiently proceeded on treatment with either zinc iodide or potassium iodide using a catalyst system of [PdCl2(PhCN)2]/LiCl/Ti(OPri)4.
  • Satoshi Moriyama, Takayuki Karakasa, Takao Saito, Shinichi Motoki
    Type: Accounts
    Subject area: AI
    1993 Volume 66 Issue 7 Pages 2124-2127
    Published: 1993
    Released: August 09, 2006
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    2-Alkyl-5,6-dihydro-3-thioacetyl-2H-naphtho[1,2-b]thiopyrans (2) exist stably in the form of monomers at room temperature, whereas unsubstituented ones at the 2-position are apt to dimerize. Based on the X-ray analysis of (2g), UV spectral study of (2), and on semi-empirical calculations, this difference of the stability could be rationalized mainly by steric reason around the heterodiene C=C–C=S system.
  • Makoto Shimizu, Kohzoh Matsukawa, Tamotsu Fujisawa
    1993 Volume 66 Issue 7 Pages 2128-2130
    Published: 1993
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    Cyclic dicarboxylic anhydrides were enantioselectively esterified with the complex formed from cinchonidine, diethylzinc, and methanol, and the half-esters obtained were readily transformed into lactones via reduction and dehydration.
  • Toshio Itahara, Naoko Ide
    1993 Volume 66 Issue 7 Pages 2131-2132
    Published: 1993
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    Treatment of 1,3-dimethyluracil, 1,3-dimethylthymine, and caffeine with benzoyl peroxide in γ-butyrolactone at 80 °C resulted in a free radical alkylation.
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