Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 67 , Issue 5
Showing 1-50 articles out of 56 articles from the selected issue
  • Anil Kumar, Ashok Panwar
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1207-1212
    Published: 1994
    Released: July 19, 2006
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    The reactions of [Ag(OH)4] with aniline and xylidines have been investigated. The stopped-flow experiments reveal kinetically distinguishable steps involving initial complexation of the substrate with the silver(III) species which is followed by its decomposition. The latter process obeys first-order kinetics and takes place with a rate constant of about 0.8 s−1 through intramolecular electron transfer from substrate to the silver(III) center. Azobenzene and p-benzoquinone have been identified as the main products of the reaction of [Ag(OH)4] and aniline. An increase in concentration of aniline enhances the yield of azobenzene which accounts for approximately 65% of the consumed aniline. This effect has been interpreted by the increased effective complexation between aniline and [Ag(OH)4] at higher concentrations. The stoichiometry of the reaction is found to vary with a change in the concentration of aniline. At higher concentrations it comes out to be 1 : 2 for [Ag(OH)4] : aniline. A mechanism of this reaction is worked out.
  • Ali Boushehri, Mohammad H. Keshavarz
    1994 Volume 67 Issue 5 Pages 1213-1216
    Published: 1994
    Released: July 19, 2006
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    The present work shows a successful extension of previous studies to molecular liquids for which the second virial coefficients are not known. Recent advances in statistical-mechanical theory of equilibrium fluids can be used to obtain an equation of state for compressed liquids. The average contact pair distribution function (G), which is at the heart of the equation of state, has the very simple form of a single curve in λb*ρ* (any substance). The effect of many-body forces may still be included in G. The temperature-dependent parameters in the equation can be calculated with reasonable accuracy for most practical purposes just from the experimental heat of vaporization and triple-point density. Thus, thermodynamic consistency is achieved by the use of two scaling parameters (ΔHν, ρt). In terms of these parameters, the reduced second virial coefficient (B2*(T)) obeys a single law of corresponding states in which α*(T) and b*(T) are only slightly modified. The correlations embrace the temperature range TtT < Tc and can be used in a predictive mode. The remaining constant parameters are best found empirically from ρt data for pure dense fluids. We tested the equation of state on several liquid mixtures. The results indicate that the density of liquid mixtures can be predicted within about 5% at any pressure and temperature.
  • Bijan Das
    1994 Volume 67 Issue 5 Pages 1217-1220
    Published: 1994
    Released: July 19, 2006
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    The free energies of transfer of electrolytes from water to ethylene glycol (EG)–water, 2-methoxyethanol (ME)–water and 1,2-dimethyoxyethane (DME)–water mixtures have been calculated at 25 °C using the scaled particle theory in conjunction with the Born charging equation. The predicted values of transfer free energies have been compared with the corresponding experimental values in order to gain insight into the preferential solvation of ions by water molecules in these solvent mixtures. The results from the present theoretical analysis indicate that in the cosolvent–water mixtures the ease of preferential solvation of electrolytes by water molecules increase in the order DME–water < ME–water < EG–water.
  • Debajyoti Bhattacharjee, Anusree Ghosh (Purkayastha), T. N. Misra
    1994 Volume 67 Issue 5 Pages 1221-1225
    Published: 1994
    Released: July 19, 2006
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    The Raman band of the C=O stretching vibration of acetone and 2-chlorobenzaldehyde has been acquired in a number of solvents of varying physicochemical properties. The effect of solute–solvent dispersion forces on the isotropic frequency shifts has been studied in different solvents (polar and nonpolar both). An attempt has been made to estimate the importance of hydrodynamic and dispersion forces in line broadening of the isotropic component, particularly using the theory of microviscosity.
  • Setsuo Kashino, Tetsuyuki Iwamoto, Etsuko Yamamoto, Tsuyoshi Shiraga
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1226-1231
    Published: 1994
    Released: July 19, 2006
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    The crystal structures of N-t-butylacrylamide, N-t-butylmethacrylamide, dimorphs of N-phenylmethacrylamide, and N-o-chlorophenylmethacrylamide have been determined by X-ray diffraction method. In all these crystals the molecules related by a glide plane are held together by an N–H···O hydrogen bond between the amide groups. The difference in the reactivity of the N-arylmethacrylamides in γ-ray induced solid-state polymerization is ascribed to the difference in an intermolecular steric effect for the molecular movement, but not to the difference in the hydrogen-bond type.
  • Katumitu Hayakawa, Takahiro Nagahama, Iwao Satake
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1232-1237
    Published: 1994
    Released: July 19, 2006
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    The conformation of poly(L-glutamic acid) was examined based on the circular dichroism spectra in solutions of ω-hydroxyalkylammonium bromides with the dodecyl or undecyl chain and the methyl-, dimethyl- or trimethylammonium moiety, as well as in normal surfactant solutions of dodecylammonium bromides with a corresponding cationic group used as a reference. The conformational change from a random coil to an α-helix was observed, depending on the chain length and head group of the surfactant. A surfactant with a longer chain length induced the α-helix at a lower concentration. A surfactant with more methyl groups has less ability for inducing an ordered conformation, presumably due to a steric hindrance, though it is more hydrophobic. No ordered conformation of poly(L-glutamic acid) was observed in surfactants with the trimethylammonium cationic group.
  • Hirotoshi Ito, Y. J. I’Haya
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1238-1245
    Published: 1994
    Released: July 19, 2006
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    Based upon a fixed partial charge approximation of Schellman, we present a linear response polarizability theory for the bandshapes of vibrational circular dichroism (VCD) and vibrational absorption spectra of biopolymers, where a polymer vibrational polarizability tensor is derived from monomer polarizability tensors in terms of Green’s operator method within a dipole–dipole approximation. The new formalism can be easily programmed by utilizing a quite similar algorithm appearing in the polarizability theory regarding electronic CD, which was previously presented. However, the theoretical framework is shown to be essentially the same as that in the excitonic treatment of the secular matrix equation method of Snir, Frankel, and Schellman, and that of their version prescribed by Diem and co-workers as an extended coupled oscillator model. Using the experimental data of the monomer transition moments of the amide I and II bands, the VCD and IR absorption bandshapes were computed for α-helical and β-sheet polypeptides. The computed VCD bandshapes were found to well predict the conformations of polypeptides. We also discuss whether an allowance is necessary or not for multistate interband mixings between constituent monomers in VCD calculations, since it is generally believed that the characteristic bands of constituent monomers can be used as localized probes to detect the conformations of biopolymers, if one follows the assumption of Schellman and co-workers that there are no interband interactions between different levels.
  • Masahiro Katoh, Tatsuya Yamazaki, Sentaro Ozawa
    1994 Volume 67 Issue 5 Pages 1246-1253
    Published: 1994
    Released: July 19, 2006
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    Carbon monoxide adsorption on alkali metal ion-exchanged ZSM-5 zeolites was investigated by IR spectroscopy. The IR peak positions and intensities of adsorbed CO, and the change in the spectra with temperature are discussed. The IR spectra for physisorbed CO over ZSM-5 zeolites were assigned to the oriented species on a cation, such as M+–C–O and M+–O–C, and the loosely adsorbed CO in the ZSM-5 pore.
  • Hiroaki Itagaki, Hiroki Murayama, Yasukazu Saito
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1254-1257
    Published: 1994
    Released: July 19, 2006
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    Catalytic cyclohexane dehydrogenation, yielding cyclohexene and dihydrogen, proceeded under photoirradiation on either a three-coordinated complex, RhCl(PCy3)2 (Cy = cyclohexyl), or a dihydride complex, RhClH2(PCy3)2, with almost the same turnover frequencies (8.4 or 8.6, respectively) attained by use of a cut-filter (UV-27) under refluxing conditions (354 K). RhCl(PCy3)2 in cyclohexane gave stoichiometric amounts of cyclohexene and RhClH2(PCy3)2 at 354 K; the latter complex yielded little H2 even at 373 K in toluene. A photocatalysis cycle for cyclohexane dehydrogenation with RhCl(PCy3)2 is proposed, where cyclohexene is yielded by thermal C–H bond dissociation and dihydrogen is photoeliminated from RhClH2(PCy3)2, regenerating the original complex.
  • Kan Hirai, Yoshiaki Amemiya, Youichiro Sano, Kyouhei Kojima
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1258-1264
    Published: 1994
    Released: July 19, 2006
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    Poly[1,3,4-oxadiazole-2,5-diyl-1,4-phenyleneimino(chloroterephthaloyl)imino-1,4-phenylene] (PBO-ClT) was prepared by the low-temperature solution polycondensation of 2,5-bis(p-aminophenyl)-1,3,4-oxadiazole with 2-chloroterephthaloyl dichloride in the presence of lithium carbonate as an acid accepter in 1-methyl-2-pyrrolidinone (NMP). The value of the inherent viscosity of PBO-ClT was 1.79 dl g−1 in sulfuric acid (0.5 g/100 ml, 25 °C). PBO-ClT was easily dissolved in NMP and N,N-dimethylacetamide (DMA). The solubility of PBO-ClT, chloro-substituted polymer, was larger than that of poly(1,3,4-oxadiazole-2,5-diyl-1,4-phenyleneiminoterephthaloylimino-1,4-phenylene) in these organic solvents. In order to enhance the tensile properties of PBO-ClT films cast from NMP solutions, the films were drawn and heat-treated under various conditions. The films were drawn in a DMA/water mixture (80 : 20, v/v, 70 °C) and subsequently heat-treated (the temperature was raised from room temp to 300 °C at a heating rate of 12—15 °C min−1). The values of the tensile strength, tensile modulus, and breaking energy of the drawn and heat-treated films were 1.30 GPa, 22.8 GPa, and 37.3 MJ m−3, respectively. These values were changed into 1.02 GPa, 18.5 GPa, and 26.9 MJ m−3 after 2 h of heat-aging at 350 °C in air. These results showed the high-temperature durability of the drawn and heat-treated materials.
  • Dock-Chil Che, Toshio Kasai, Hiroshi Ohoyama, Keiji Kuwata
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1265-1268
    Published: 1994
    Released: July 19, 2006
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    Using the oriented molecular beam, the orientational dependence of the CN(A) and of the CN(B) radical formation has been reinvestigated to obtain orientational opacity functions for the Ar(3P) + CF3CN reaction. The steric model with the Legendre polynomial expansion gave the best-fit functions which have two reactive sites on CF3CN. One site locates at the CN end and the other one near the C–F bonds. It was found that the CF3 end attack is the least favorable for both CN formations. These results substantiate the relationship between the shape of the 2e and 7a1 molecular orbitals of CF3CN and the orientational opacity functions.
  • Teruhisa Komura, Hironobu Sakabayashi, Koshin Takahashi
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1269-1273
    Published: 1994
    Released: July 19, 2006
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    The photoelectrochemical behavior of polyaniline (PA) film was investigated in acidic aqueous solutions. In the presence of NO3 in the solutions, a large cathodic photocurrent was observed at lower potentials than 0.1 V vs. Ag/AgCl. The dependence of the current quantum efficiency at −0.1 V on the wavelength of light indicated that the photocurrent was due to the absorption of ultraviolet light by the reduced film of PA. The variations in potential and spectrum of the reduced film under open-circuit conditions confirmed the transformation of PA from a reduced state to a radical cation state with the ultraviolet irradiation. In conclusion, the cathodic photocurrent at −0.1 V could result from the photo-induced oxidation of the reduced PA film by NO3. A film resistance-potential relationship was examined in connection with the pH dependence of the photoresponse of PA. The potential giving a minimum resistance at a given pH shifted to lower potentials with increasing pH. It can be presumed that a maximum in the photocurrent–pH curve arises from the increase in the ease of oxidation of the reduced film with an increase in pH.
  • Risa Asanuma, Hiroshi Tomizawa, Akio Urushiyama, Eiichi Miki, Kunihiko ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1274-1280
    Published: 1994
    Released: July 19, 2006
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    Some kinds of {RuII-NO+}-type complexes containing a diethylenetriamine ligand were prepared from hydrous RuX3·NO (X = Cl or Br) and diethylenetriamine. Among them, the crystal and molecular structures for trans-mer-[RuCl2(dien)NO]PF6 (1) and mer-[RuBr3(Hdien)NO]Br·H2O (2) (dien = diethylenetriamine) were determined by X-ray diffraction. The crystal of 1 was monoclinic, space group P21/a with a = 21.296(4), b = 6.602(2), c = 10.079(2) Å, β = 97.12(2)°, Z = 4, and final R = 0.0307, and the crystal of 2 was orthorhombic, space group P212121 with a = 11.988(4), b = 17.234(9), c = 7.141(2) Å, Z = 4, and final R = 0.0825. In 1, the two chloro ligands were in the trans arrangement and the dien was in the meridional arrangement as a tridentate ligand. In 2, the three bromo ligands were in the meridionalarrangement with the Hdien coordinated to the ruthenium through one terminal and central nitrogen atoms as a bidentate ligand, and the remaining uncoordinated terminal moiety was –NH3+. The trans-strengthening effect that is expected to be caused by the NO was not observed for the Ru–N(dien) bond. The synthesized complexes were also characterized by IR and NMR spectra.
  • Tsuyoshi Kijima, Kenji Sakaguchi, Kaoru Ohe
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1281-1285
    Published: 1994
    Released: July 19, 2006
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    The individual and mixed uptakes of [Pt(en)2]2+ and [PtCl2(en)2]2+ ions by Na-montmorillonite have been studied at 25 °C. In the individual uptakes, the Pt(IV) complex ions are intercalated beyond the cation exchange capacity of the host, which is in striking contrast to the Pt(II) complex ions which are taken up through the capacity. Both complex ions are arranged as a monolayer in which their square-planar PtII(en)2 and PtIV(en)2 planes are parallel and perpendicular to the silicate layers, respectively. The uptake reaction with an equimolar solution of both complexes results in the predominant intercalation of the Pt(II) complex ions, while that with a Pt(IV)-riched mixed solution yields a co-intercalated monolayer in which the Pt(IV) complex ions are held with their square-planar planes tilted by ca. 52° with respect to the silicate layer.
  • Alaa S. Amin, S. Shakra, A. A. Abdalla
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1286-1289
    Published: 1994
    Released: July 19, 2006
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    The synthesis, spectral characteristics, and analytical application of 2,3-Dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (DCHNAQ) are described. A simple, rapid, selective, and sensitive spectrophotometric method for the determination of microgram amounts of gold, alone, or in the presence of associated metals, is developed, based on the color reaction between the metal ion and the reagent. The yellowish brown complex (λmax = 575 nm) has stoichiometric ratio (1 : 1) [metal : ligand] over the pH range 3.4 to 7.0. Beer’s law is obeyed over the concentration range 0.1—6.9 μg cm−3 of gold. The molar absorptivity and Sandell’s sensitivity of the method are 1.52 × 104 dm3 mol−1 cm−1 and 0.016 μg Au cm−1 respectively. The relative standard deviation for six replicate determination of 2.95 μg cm−3 of gold(III) is 1.37%. The interference of various ions has been studied and conditions were developed for the determination of gold in alloys and some synthetic samples without the need for extraction or heating.
  • Noboru Wakatsuki, Yoshinori Sasaki
    1994 Volume 67 Issue 5 Pages 1290-1295
    Published: 1994
    Released: July 19, 2006
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    A molybdenum sheet was selenidized at a selenium vapor pressure of 0.40—13.3 kPa at 773—973 K by means of a sealed-tube method. X-Ray diffraction patterns and an electron probe microanalysis of the product films showed that a single layer comprising MoSe2 was formed under all of the selenidization conditions employed. All of the selenidizations obeyed a parabolic rate law and, therefore, the rate-determining step was apparently a diffusion process. The parabolic rate constant (Kp) was expressed as a function of the absolute temperature, and the selenium vapor-pressure dependence of Kp could be clearly recognized. A marker experiment indicated that selenium was the component which diffused.
  • Nobushige Yamamoto, Hiroshi Hirasawa, Hidenobu Ishida, Tetsu Tatsuma, ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1296-1300
    Published: 1994
    Released: July 19, 2006
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    The cathodic electrolysis of propylene carbonate containing lithium perchlorate was studied by means of an in-situ quartz crystal microbalance technique. A lithium compound was deposited at about +1.5 V vs. Li/Li+ and dissolved at about +4.0 V vs. Li/Li+. In constant potential electrolysis at +0.9 V vs. Li/Li+, the deposition process was divided into two stages. In the first stage, in which lithium carbonate was most probably deposited, an electrode reaction of ferrocene which was added to the solution was gradually retarded. In the second stage, in which some chemical reaction proceeded dominantly, the electrode reaction of ferrocene was almost completely blocked. A cathodic charge of +3.0 mC cm−2 was necessary for almost complete blocking.
  • Tadashi Segawa, Shinji Suehara, Tamio Kamidate, Hiroto Watanabe
    1994 Volume 67 Issue 5 Pages 1301-1305
    Published: 1994
    Released: July 19, 2006
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    The chemiluminescence (CL) which occurred during oxidation of umbelliferone catalyzed by horseradish peroxidase (HRP) oscillated, when a high concentration of H2O2 was employed. The oscillatory CL response reflected periodic changes in the concentration of HRP intermediates between active states, compound I and compound II, and an inactive state of compound III. When the reaction was initiated, the CL was generated by the action of compound I and compound II. Then, the concentration of compound III was gradually increased, because the formation of compound III from compound II and H2O2, the rate constant of which was very little, could not be ignored in a high H2O2 condition; thus the CL was decreased by degrees. Compound III was then decomposed into the active HRP intermediates and the CL was re-increased. The repetition of those processes causes the oscillation. A kinetic study on the mechanism of the oscillatory CL was performed with trial rate equations.
  • Sharad Mahadeo Kakade, Vijay Malhar Shinde
    1994 Volume 67 Issue 5 Pages 1306-1309
    Published: 1994
    Released: July 19, 2006
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    A simple and rapid method for extractive separation of vanadium(V), niobium(V), and tantalum(V) from halide media has been worked out using triphenylphosphine oxide in toluene as an extractant. The optimum conditions for extraction and separation have been evaluated from critical study of various variable factors. The log–log plots are used to ascertain probable extractable species. The method is applicable to the analysis of standard alloy samples and synthetic mixtures. The results are reproducible and accurate.
  • Hisano Kawasaki, Masami Kusunoki, Yoshihito Hayashi, Masatatsu Suzuki, ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1310-1319
    Published: 1994
    Released: July 19, 2006
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    A dimer-of-di(μ-oxo)manganese(III)manganese(IV)-dimers with two coordinated water molecules, [{Mn2(tmdp)(O)2(H2O)}2](CF3SO3)4·6H2O (1), was prepared, where Htmdp is 1,5-bis[bis(2-pyridylmethyl)amino]-3-pentanol. Crystal structure of 1 was determined by X-ray structure analysis. 1 crystallizes in triclinic space group, with a = 16.543(1), b = 19.097(2), c = 13.393(1) Å, α = 94.450(7)°, β = 90.698(6)°, γ = 84.997(7)°, V = 4202.4(6) Å3, and Z = 2. The complex cation consists of two di(μ-oxo)manganese(III)manganese(IV) dimers which are linked by two tmdps and hydrogen bonding network between two coordinated water molecules and two alkoxo groups to form a dimer-of-dimers with a bilayered structure with dimer-dimer separation of 5.9 Å. The Mn–Mn separations are 2.644(2)—2.651(2) Å. Magnetism of 1 was well interpreted in terms of the model based on two kinds of the exchange interactions between Mn(III) and Mn(IV); the intradimer interaction (J1 = −145 cm−1) through di(μ-oxo) bridges and the interdimer interaction (J2 −0.2 cm−1) through hydrogen bonding network. The interdimer exchange interaction (J2) results in a triplet ground state. The ESR spectrum of a frozen solution sample of 1 showed a relatively intense “ΔMs = 2” signal centered at g = 4.5, which is only 7.6 times weaker than a much broader “ΔMs = 1” signal at g = 2.0. The best computer simulation revealed near rhombic zero-field splittings with |D| 0.07 cm−1 and |E| 0.023 cm−1, and Mn-hyperfine broadening, which are appropriate for the triplet ground state of such a tetrameric dimer-of-di(μ-oxo)manganese(III)manganese(IV)-dimers with 5.9 Å separation. The observed zero-field splittings could be interpreted in terms of an incomplete quenching of the crystal field effect of each Mn(III) ion in the triplet ground state mixed with the excited-state spin configurations through the J2 interactions. Cyclic voltammogram exhibited a quasi reversible wave (E1/2 = 0.98 V vs. SCE) and an irreversible oxidation wave at 1.10 V vs. SCE in acetonitrile. Constant potential electrolysis at 1.00 V vs. SCE indicated that the quasi reversible wave is a one-electron transfer process and corresponds to Mn4(III, IV, IV, IV)/Mn4(III, IV, III, IV) redox couple. A one-electron oxidized species which was generated electrochemically showed a so called sixteen hyperfine pattern at g = 2.0, supporting the presence of di(μ-oxo)manganese(III)manganese(IV) and di(μ-oxo)dimanganese(IV) species in the tetramer. Constant potential electrolysis at 1.20 V vs. SCE resulted in a decomposition of the complex.
  • Honoh Suzuki, Makoto Koide, Shin-ichi Ishiguro
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1320-1326
    Published: 1994
    Released: July 19, 2006
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    Solution equilibria between zinc(II) and halide ions have been studied in N,N-dimethylacetamide (DMA) by calorimetry at 298 K. Formation constants, enthalpies, and entropies of mononuclear binary complexes, [ZnIICln](2−n)+ (n = 1—4), [ZnIIBrn](2−n)+ (n = 1—3), and [ZnIIIn](2−n)+ (n = 1,2), have been determined. In addition, mixed-ligand complexes have been detected in ternary Zn–Cl–Br and Zn–Br–I systems: [ZnClBr], [ZnCl2Br], [ZnClBr2], and [ZnBrI]. Complexation is more favorable and more exothermic in the order Cl > Br > I. Formation of the monohalogeno complexes is particularly endothermic and entropy-productive, suggesting that geometric transition from octahedral to tetrahedral is complete at this step, i.e., all the halogeno complexes are tetrahedral. Thus, the transition occurs earlier in DMA than in N,N-dimethylformamide (DMF). Compared with DMF, complexation in DMA is more favorable and more exothermic exclusively at the first and second steps, and little difference is found for the later steps. This is attributed to the steric hindrance of DMA molecules, which is crucial in octahedral coordination structures but not important in tetrahedral geometry. Among the first-row bivalent transition metal ions, ZnII is exceptional in its ΔHβ4° and ΔSβ4° values of overall formation of the tetrachloro complex, consistent with the existence of a solvation equilibrium: [Zn(dma)6]2+ [Zn(dma)4]2+ + 2dma.
  • Kazuki Nakanishi, Hiroshi Komura, Ryoji Takahashi, Naohiro Soga
    1994 Volume 67 Issue 5 Pages 1327-1335
    Published: 1994
    Released: July 19, 2006
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    Phase separation and gelation behaviors have been studied for the acid-catalyzed, alkoxide-based silica systems containing poly(ethylene oxide) (PEO) with an average molecular weight of 100000. Gels with micrometer range interconnected porous morphology were obtained similarly to the systems containing other water-soluble polymers, in which the structure development by the spinodal decomposition and the gel forming process take place concurrently. In spite of the morphological similarity, the thermogravimetric analysis revealed that the reacting solution decomposed into phases one rich in PEO and the other rich in solvent. Macropore volume of gels depended mainly on the amount of solvent phase.
  • Tomohiro Suzuki, Kin-ichi Tsunoda, Hideo Akaiwa
    1994 Volume 67 Issue 5 Pages 1336-1340
    Published: 1994
    Released: July 19, 2006
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    The adduct formation and the masking effect due to the addition of neutral ligands to mobile phase were applied to improve the mutual separation of some metal chelates of 3-mercapt-1,5-diphenylformazane (dithizone) in reversed-phase high-performance liquid chromatography. The addition of trioctylphosphine oxide and triethanolamine (TEA) was effective for controlling the retention time of some metal dithizonates. The addition of TEA made it possible to separate the overlapped peaks of nickel(II) and zinc(II) dithizonates from each other. On the other hand, 1,10-phenanthroline (phen) masks NiII and ZnII selectively depending upon stabilities of their charged phen complexes. The degree of the masking effect of phen was predictable to some extent from the stability constants of the metal dithizonates and the metal–phen complexes.
  • Motowo Yamaguchi, Masahiko Saburi, Sadao Yoshikawa, Takamichi Yamagish ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1341-1347
    Published: 1994
    Released: July 19, 2006
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    The oxidation of the α-amino acidato cobalt(III) complexes with 2,3,2-tet (=3,7-diazanonane-1,9-diamine) or its derivative, where amino acidate ligand was phenylglycinate, alaninate, valinate N-methylalaninate, or prolinate, by potassium permanganate was achieved to yield the corresponding α-imino acidato complexes, [CoIII{N(R1)=C(R2)CO2}(N4)]2+.
  • Masahiro Mikuriya, Masato Yamamoto, Wasuke Mori
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1348-1358
    Published: 1994
    Released: July 19, 2006
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    A series of alkoxo-bridged copper(II) complexes with 2-dialkylaminoethanol and 1-dialkylamino-2-propanol, [Cu2(R2NCH2CH2O)2(NCS)2] and [Cu2{R2NCH2CH(CH3)O}2(NCS)2] (R = CH3, C2H5, n-C3H7, i-C3H7), have been prepared and characterized by infrared and electronic spectroscopies, and temperature dependence of magnetic susceptibilities. The crystal structures of [Cu2{i-C3H7)2NCH2CH2O}2(NCS)2] and [Cu2{R2NCH2CH(CH3)O}2(NCS)2] (R = CH3, C2H5, n-C3H7, i-C3H7) have been determined by X-ray crystallography. The compounds are polymeric with copper atoms alternately bridged by two alkoxo oxygen atoms and two thiocyanate ions, except for [Cu2{(i-C3H7)2NCH2CH(CH3)O}2(NCS)2] which is a discrete alkoxo-bridged dinuclear molecule. The unusual magnetic properties are discussed in relation to the crystal structures.
  • Takashi Yamanoi, Kazumi Nakamura, Hiroshi Takeyama, Kenji Yanagihara, ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1359-1366
    Published: 1994
    Released: July 19, 2006
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    The reactions of mannopyranosyl dimethylphosphinothioates and alcohols using silver perchlorate as an activator in the presence of molecular sieves 4A in benzene at room temperature gave the 1,2-trans-α-mannopyranosides in good yields. On the other hand, 1,2-cis-β-mannopyranosides could be obtained from the dimethylphosphinothioates by the combined use of iodine and 5 mol% triphenylmethyl perchlorate as an activating system. The syntheses of the derivatives of αMan(1→6)[αMan(1→3)]Man and βMan(1→4)GlcNAc units of glycoproteins by these methods are described.
  • Yasuhito Yamamoto, Hideo Kise
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1367-1370
    Published: 1994
    Released: July 19, 2006
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    The catalytic activity of α-chymotrypsin (CT) in the transesterification of N-acetyl-L-tyrosine methyl ester to its ethyl ester in aqueous-organic media was markedly enhanced by replacing a part of water with formamide. The activity of CT was strongly dependent on the formamide/water ratio, and excess formamide retarded the activity. Addition of formamide to reaction mixtures at constant water contents exhibited similar activation–deactivation profiles for CT. A kinetic study revealed that the rate acceleration is due to an increase in kcat rather than a change in Km. At a given concentration of amides (0.5 M, M = mol dm−3), propionamide and DMF were much less effective than formamide for activation of CT. The results suggest that formamide interacts with CT in a different way from water.
  • Yutaka Kaneko, Hiroshi Kita, Kazuo Mukai, Katsuyuki Kawano
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1371-1379
    Published: 1994
    Released: July 19, 2006
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    4H-1,3-Benzodioxin-6-ol (HBD) derivatives 15, new tocopherol (Vitamin E) analogs, have been synthesized by condensation of acetaldehyde with the corresponding hydroquinone. For each HBD derivative except for 4, two diastereomeric isomers were produced. These stereoisomers were separated by column chromatography and the configuration of each isomer was identified by two dimensional NMR techniques and ESR measurements of the HBD radicals. The second-order rate constants, ks, for the reaction of 9 kinds of HBD derivatives with substituted phenoxyl radical (PhO·) in ethanol have been measured with a stopped-flow spectrophotometer. These HBD derivatives reacted at rates that were only about 5—20% of those observed with the corresponding tocopherols. The logs of the second-order rate constants, ks, obtained for HBD derivatives were found to correlate with their peak oxidation potentials, Ep. Electron spin resonance measurements were done for HBD radicals in toluene, and the proton hyperfine coupling constants, aiH, and giso-values were determined. The log of the rate constants, ks, was also found to correlate with the sum of the hyperfine coupling constants (a5H + a7H) at 5- and 7-positions of both HBD radicals and tocopheryloxyl radicals, that is, the unpaired π-spin densities (ρ5 + ρ7) at the two ortho carbon atoms.
  • Masataka Harada, Masahiko Sisido, Jyunzo Hirose, Mamoru Nakanishi
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1380-1385
    Published: 1994
    Released: July 19, 2006
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    Monoclonal antibodies against a tetrapeptide carrying a photochromic azobenzene moiety (Glu–azoAla–Gly–Gly, azoAla = Lp–phenylazophenylalanine) were prepared under conditions where the azobenzene moiety was in the trans form. The binding of the hapten peptide to the antibody was investigated by fluorescence quenching of the antibodies by the hapten peptide. The results indicated that the antibodies bind the hapten peptide when the azobenzene moiety is in the trans form, but release the peptide in the cis form. The mechanism of photoreversible binding and release was studied using a pulsed laser light. Photoisomerization of the hapten peptide was found to occur inside the binding site, indicating that the latter is flexible enough to allow the transcis photoisomerization within a few ten picoseconds.
  • Alaka Srivastava, Vandana Srivastava, Shiva M. Verma, Vasantha Pattabh ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1386-1389
    Published: 1994
    Released: July 19, 2006
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    1H, 13C NMR and X-ray crystallography have demonstrated the azomethine structure of the addition product obtained from N-amino-2,3-(9,10-dihydro-9,10-anthracenediyl)succinimide and diethyl acetylenedicarboxylate. The exo cyclic nitrogen exists in sp2-state and its lone pair lies in anti orientation while the diethyl succinate moiety has been demonstrated to be syn to the cage and orthogonal to the succinimide plane. On acetylation the product is transformed into N-acetyl derivative which exhibits restricted rotation about N–N bond and a preferred conformation with N-acetyl in syn-orientation.
  • Magdi Abdel Azzem, Magdi Zahran, Ezzat Hagagg
    1994 Volume 67 Issue 5 Pages 1390-1393
    Published: 1994
    Released: July 19, 2006
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    The controlled potential anodic oxidation of catechol in the presence of 1,3-dimethylbarbituric acid was carried out in aqueous solution containing sodium acetate in an undivided cell at graphite anode and nickel hydroxide electrode. In a sequence of Michael addition of the barbiturate to the anodically formed benzoquinone, dispiropyrimidine derivative has been obtained in moderate yield (35—36%). A mechanism has been proposed and confirmed on the basis of CPE product, identification through IR, 1H NMR, 13C NMR, and MS spectroscopy.
  • Tadahiro Kato, Masako Tomita, Miho Takigawa, Hiroyuki Iwasaki, Toshifu ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1394-1398
    Published: 1994
    Released: July 19, 2006
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    The acetone extract of Alisma rhizomes were found to possess inhibitory effects on vascular contraction induced by high concentration of KCl. With the aids of bioassay, the effective components were pursued by purification with chromatographies, resulting in the characterization of six protostane type triterpenes (alisol C and its analogues) and a known sesquiterpene, alismoxide as the active compounds.
  • Naoaki Fukada, Yasuo Hasegawa, Yasuo Kamiya, Hidenobu Yabuta, Tatsuo T ...
    1994 Volume 67 Issue 5 Pages 1399-1404
    Published: 1994
    Released: July 19, 2006
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    2-Oxo-1,3-imidazolidinebis(carbothioamide)s and 2,4-dioxo-1-imidazolidinecarbothioamides were prepared by the reaction of dimethyl 2-oxo-1,3-imidazolidinebis(carbodithioate) (1b) and methyl 2,4-dioxo-1-imidazolidinecarbodithioate (2b) with amines, respectively. The reaction of 2-oxazolidone with carbon disulfide gave 2-oxo-3-oxazolidinecarbodithioic acid, the methyl ester of which (4b) led to 2-oxo-3-oxazolidinecarbothioamides. Esters 1b, 2b, and 4b reacted with hydrazine hydrate to give the corresponding thiohydrazides, from which thiosemicarbazone derivatives were obtained. Macrocyclic thioureas were synthesized by the reaction of 1b with aliphatic diamines, polyether-containing diamines, and polyamines.
  • Jun Okubo, Takayasu Shimazaki, Shin-ichi Sato, Hiraku Shinozaki
    1994 Volume 67 Issue 5 Pages 1405-1411
    Published: 1994
    Released: July 19, 2006
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    The polarized UV absorption spectrum of 1,3-diphenyl-1,2-propadiene (DPA) was measured in a stretched polymer film at 101 K, and the polarization directions of the electronic absorption bands were determined. Pariser–Parr–Pople (PPP) calculations extended to three dimensions were performed, and the position, intensity, and polarization of each absorption band of DPA were obtained from the calculations. The observed 289.8 and 265.2 nm bands polarized along the longer molecular axis were assigned to the calculated S1←S0 and S3←S0 transitions, respectively, and the 237.1 nm band along the shorter molecular axis was assigned to the S4←S0 transition. The results of configuration analysis indicate that the second transitions (at 260.5 nm) of two styrenes, whose π-electronic systems are perpendicular to each other, contribute equally to the third and fourth transitions observed at 265.2 and 237.1 nm of DPA. In addition, it was clarified that the first absorption band of DPA corresponding to Parity’s forbidden transition was intensified by an increase of the ionization energy of the sp hybridized carbon atom in the allenic moiety.
  • Tsuyoshi Satoh, Yasumasa Hayashi, Yasuhiro Mizu, Koji Yamakawa
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1412-1418
    Published: 1994
    Released: July 19, 2006
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    Treatment of 1-chloroalkyl phenyl sulfoxides with a base gave carbenoids rather than free carbenes. The carbenoids were successfully used in a new method for homologation of ketones to α-sulfinyl ketones. Treatment of the carbanion of chloromethyl phenyl sulfoxide with ketones gave the adducts, α-chloro β-hydroxy sulfoxides, in nearly quantitative yields. The adducts were treated with excess lithium diisopropylamide to give one-carbon homologated α-sulfinyl ketones via α-sulfinyl β-oxido carbenoids in moderate to good yields. This type of reaction was found not to occur with the corresponding sulfones.
  • Hiroshi Nishida, Tatsuya Fujii, Yoshiaki Abiru, Katsuya Yatsuki, Masas ...
    1994 Volume 67 Issue 5 Pages 1419-1426
    Published: 1994
    Released: July 19, 2006
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    When a tertiary amine (4,NM441) is synthesized from 4-bromomethyl-5-methyl-1,3-dioxol-2-one (DMDO-Br) and a secondary amine (3,NM394) in N,N-dimethylformamide (DMF), the quaternary ammonium salt 5, the ring-opened compound 6, and the 1,2-adduct 7 are formed as by-products. The tertiary amine 4 is formed by nucleophilic attack of 3 on the α-carbon to the bromine atom of DMDO-Br. The ring-opened compound 6 is formed by nucleophilic attack of 3 on carbonyl carbon of DMDO-Br. The quaternary ammonium salt 5 is formed by the reaction of DMDO-Br with 4 (the Menshutkin reaction). Main pathway for the formation of 7 is the Michael addition of 3 to 6. Kinetics of the reactions have been studied and the methods to obtain 4 suppressing the formations of 5, 6, and 7 have been proposed based on the kinetic results.
  • Ikutaro Saji, Katsumi Tamoto, Yoshihiro Tanaka, Hiroshi Miyauchi, Koji ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1427-1433
    Published: 1994
    Released: July 19, 2006
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    The stereoselective synthesis of antifungal agent threo-2-(2,4-difluorophenyl)-3-methylsulfonyl-1-(1H-1,2,4-triazol-1-yl)-2-butanol (SM-8668) is described. The key step is the selective synthesis of intermediate threo-2(2,4-difluorophenyl)-2-(1-substituted ethyl)oxirane. threo-2-(2,4-Difluorophenyl)-2-(1-methylthioethyl)oxirane was synthesized threo-selectively by the reaction of 1-(2,4-difluorophenyl)-2-methylthio-1-propanone with dimethyloxosulfonium methylide in a heterogeneous media consisting of a hydrophobic solvent and aqueous alkaline solution.
  • Noriyuki Tanaka, Hiroyuki Yamazaki, Hirochika Sakuragi, Katsumi Tokuma ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1434-1440
    Published: 1994
    Released: July 19, 2006
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    (E)-3-(4-Methoxyphenyl)-3-pentenyl 6-cyano-9-phenanthrenecarboxylate as well as the corresponding 9-phenanthrenecarboxylate exhibited exciplex emission and gave [2+2] photocycloadducts of the double bond with the phenanthrene 9,10 bond (a cyclobutane) and with the ester carbonyl group (an oxetane). The involvement of plural exciplex intermediates for these phenomena was proposed on the basis of the temperature and solvent dependence of quantum efficiencies of fluorescence and cycloadditions as well as of the effects of quenchers of exciplex intermediates.
  • Hidemitsu Uno, Katsuji Sakamoto, Takashi Tominaga, Noboru Ono
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1441-1448
    Published: 1994
    Released: July 19, 2006
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    The reactions of 2-aryl-1-fluorovinyl phenyl sulfones with carbanions derived from isocyanoacetates gave mixtures of 3-aryl-4-fluoro-2-pyrrolecarboxylates and 3-aryl-4-fluoro-4-phenylsulfonyl-2-isocyanobutanoates, simple Michael addition products, in variable ratios depending upon the conditions employed. On the other hand, the reaction of 1-fluoro-1-propenyl phenyl sulfone afforded mainly the simple Michael addition products in moderate yields as well as a small amount of 4-phenylsulfonyl-3-methyl-2-pyrrolecarboxylates and a trace amount of 4-fluoro-3-methyl-2-pyrrolecarboxylates. 1-Fluoropropenyl phenyl sulfoxide underwent mainly the simple Michael addition to give butenoates and a small amount of 4-fluoro-2-pyrrolecarboxylates.
  • Kuniaki Tatsuta, Manabu Itoh
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1449-1455
    Published: 1994
    Released: July 19, 2006
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    The first total synthesis of (+)- and (−)-neopyrrolomycins (11a and 11b) is detailed based on regioselective chlorinations of 3,5-dichloroanisole (2) and 1-(2,3,4-trichloro-6-methoxyphenyl)-1H-pyrrole-2-carboxylic acid (8) with isocyanuric trichloride, followed by optical resolution of racemic neopyrrolomycin (11) with N-(p-tolylsulfonyl)-L-phenylalanyl chloride. Several analogs (2125) have been prepared from the intermediates, and the structure-activity relationships are also discussed.
  • Kenichi Oyaizu, Naoki Iwasaki, Kimihisa Yamamoto, Hiroyuki Nishide, Ei ...
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1456-1461
    Published: 1994
    Released: July 19, 2006
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    A catalytic amount of Lewis acids ([Lewis acid]/[Disulfide] = 1/200) facilitated electron transfer from diaryl disulfides to a stoichiometric amount of another oxidizing agent by which linear poly[thio(1,4-arylene)] was produced. Such Lewis acids as SbCl5 and FeCl3 facilitated oxidation of diphenyl disulfide by quinones more efficiently than protic acids such as CF3COOH, where the Lewis acid showed more than 200-fold more activity than the protic acid. Oxovanadium complex-catalyzed oxygen-oxidation of disulfides was also facilitated by these Lewis acids. The catalysis of these Lewis acids includes not only the activation of quinones or the oxovanadium complex, but also the lowering of the oxidation potential of the monomers.
  • Seiichi Inokuma, Shigefumi Sakai, Reiko Katoh, Jun Nishimura
    1994 Volume 67 Issue 5 Pages 1462-1467
    Published: 1994
    Released: July 19, 2006
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    Dihydroxycrownophanes (2ac) were conveniently synthesized by intramolecular [2 + 2] photocycloaddition, and their derivatives with two cation-ligating side chains (3a6a) were also readily prepared by the reaction of 2ac and the corresponding halides in the presence of NaH. All of the crown compounds obtained were used as ionophores in single extraction experiments of heavy metal cations including transition metal cations in a H2O–CH2Cl2 system. Although 3a did not extract any alkaline earth metal cation at pH 7.0, it showed high affinity toward Pb2+ even under acidic conditions (pH 4.7). Crownophanes (4ac) having two 2-pyridylmethyl ligands efficiently extracted Ag+ with excellent selectivity.
  • Dong-June Chung, Yoshihiro Ito, Yukio Imanishi
    1994 Volume 67 Issue 5 Pages 1468-1471
    Published: 1994
    Released: July 19, 2006
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    A glucose-sensitive insulin-releasing protein device was synthesized by connecting insulin to glucose oxidase (GOD) through a disulfide linkage. Insulin was released from the device by reductive cleavage of the disulfide linkage with electrons generated upon oxidation of glucose by GOD. Some protein devices containing different amounts of insulin were synthesized by varying the feed concentration in the synthetic process. The amount of released insulin increased with the increase of insulin content in the protein device. Although using urea enhanced the amount of insulin coupled to GOD, the efficiency of insulin release did not increase. The fluorescence quenching of the protein device containing fluorescence-labelled insulin with acrylamide showed that insulin was incorporated into the interior domain of the GOD molecule by addition of urea.
  • Makoto Hino, Kazushi Arata
    1994 Volume 67 Issue 5 Pages 1472-1474
    Published: 1994
    Released: July 19, 2006
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    Solid superacid catalysts, which were active for the skeletal isomerization and cracking of isopentane, were obtained by impregnating hydroxides or amorphous oxides of Sn, Ti, and Fe with ammonium metatungstate and then calcining in air; the maximum activity was observed with calcination at 1000 °C for the material of Sn and 700 °C for those of Ti and Fe (11—13 wt% W).
  • Ho-Hi Lee, Hitoshi Senda, Akio Kuwae, Kazuhiko Hanai
    1994 Volume 67 Issue 5 Pages 1475-1478
    Published: 1994
    Released: July 19, 2006
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    Crystals of allocinnamic acid having a melting point of 68 °C are monoclinic: space group P21/n with a = 10.157(4), b = 9.798(2), c = 15.770(4) Å, β = 91.35(3)°, and Z = 8. The structure was solved by direct method and refined to a final R value of 0.059 for 3832 reflections [I > 3σ(I)]. There are two independent molecules (A, B) in the asymmetric unit. The two molecules are hydrogen bonded through carboxylic acid groups [O1A···O2B 2.643(5) Å, O2A···O1B 2.629(5) Å]. Geometric differences between the two molecules are found in the torsion angle around the C(phenyl)–C(olefin) bond and the olefinic C=C bond length. In the high-resolution solid-state 13C NMR spectra resonances for the C2, C3, and C4 carbons are observed as doublet features in accordance with the conformational variations observed in X-ray crystallography.
  • Ryoka Matsushima, Kiyonari Hiramatsu, Katsuhisa Shimamoto
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1479-1482
    Published: 1994
    Released: July 19, 2006
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    Noncentrosymmetric and thermostable single crystals (space group of Pna21) of N-(2-butenyl)-p-nitroaniline were obtained by slow crystallization from solution, with SH activities of 150—200 × urea measured by the SHG powder method with a 1064 nm Nd : YAG laser source. Single crystals of N-(3-methyl-2-butenyl)-, N-(2-propenyl)-, or N-butyl-p-nitroaniline showed nil SH activities. On the other hand, mixed crystals of these derivatives with p-nitroaniline showed much higher SH activities (up to 2000), though thermally not stable.
  • Masamichi Tsuboi, Toyotoshi Ueda, Koichi Ushizawa, Yasuhiro Sasatake, ...
    1994 Volume 67 Issue 5 Pages 1483-1484
    Published: 1994
    Released: July 19, 2006
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    Raman spectrum of thymidine-13C5, in which five C atoms of the deoxyribose moiety are uniformly substituted with 13C atoms, has been examined in the crystalline state with 488.0 nm excitation. Some of the Raman bands were observed at appreciably shifted frequencies from those of the corresponding Raman bands of the natural thymidine, and they were assigned to some vibrations involving deoxyribose motions.
  • Takuya Takeda, Takao Oi
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1485-1487
    Published: 1994
    Released: July 19, 2006
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    A 11B NMR signal, which corresponded to a 1 : 1 complex of the borate ion and 1,4-butanediol (considered to have a seven-membered ring structure), was observed in aqueous solutions. The stability of the complex was lower than those of complexes with five- or six-membered rings between borate ions and structurally similar diols.
  • Takashi Yamanoi, Ayumi Fujioka, Toshiyuki Inazu
    Type: Accounts
    Subject area: AI
    1994 Volume 67 Issue 5 Pages 1488-1491
    Published: 1994
    Released: July 19, 2006
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    The reactions of 2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl dimethylphosphinothioate and phenolic compounds gave the corresponding aryl α-D-glucopyranosides predominantly in good yields, even when the trimethylsiloxy derivatives of benzene, which are known to afford 1-aryl-1-deoxy-D-glucopyranoses by the conventional methods, were used as acceptors. On the other hands, 1-ary-1-deoxy-β-D-glucopyranose was obtained in good yield when 1,3,5-trimethoxybenzene was used as an acceptor.
  • Masao Hirano, Hiroyuki Kudo, Takashi Morimoto
    1994 Volume 67 Issue 5 Pages 1492-1494
    Published: 1994
    Released: July 19, 2006
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    The title oxidation of a variety of sulfides was effectively performed in dichloromethane in the presence of H+-exchanged zeolite F-9, affording the corresponding sulfoxides in good yields under mild and neutral conditions.
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