Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 61 , Issue 6
Showing 1-50 articles out of 84 articles from the selected issue
  • Hatsumi Urayama, Tamotsu Inabe, Takehiko Mori, Yusei Maruyama, Gunzi S ...
    1988 Volume 61 Issue 6 Pages 1831-1836
    Published: 1988
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    AzaTCNQ ((4-dicyanomethyl-1-pyridinio)dicyanomethanide) is employed as an organic acceptor to form new organic conductors with a TTF family such as TTF, TMTTF, TMTSF, HMTTF, and DBTTF. Among them, TMTTF and TMTSF give 2:1 single crystals and the latter affords the most conductive complex, showing a metallic characteristic down to 150 K. This can be observed by measuring the thermoelectric power and the ESR spectra. A crystal structure analysis indicates that only TMTSF molecules stack to form one-dimensional conduction pathways, while AzaTCNQ molecules are arranged side-by-side and oriented almost perpendicular to the donor molecules. There exists an orientational disorder of the nitrogen atom in the pyridine skeletone of an AzaTCNQ molecule, which may be associated with the weak temperature dependence of the electrical conductivity.
  • Hiroshi Ichikawa, Atsushi Shigihara
    1988 Volume 61 Issue 6 Pages 1837-1843
    Published: 1988
    Released: June 27, 2006
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    The authors examined 22 different basis sets in order to determine exactly how they reproduce the relative kinetic and potential energies. In an attempt to find the calculation error of such energy components, the virial relationship has been used between two conformations in which all bond lengths are optimized with respect to the total energy: i.e., the relationship, ΔV=−2ΔT, where ΔV and ΔT are the differences in the potential and kinetic energies. The degree of error was compared in terms of the relative virial error ((ΔET)⁄ΔE) to the difference in the total energies (ΔE). STO-NG was found to give a large amount of casual error, up to 500% to ΔE. Such an error could be dramatically improved by using a split-valence method. It should be noted that 4-31G and 6-31G methods resulted in a small amount of error and that the inclusion of polarization functions does not always improve the amount of error.
  • Takashi Kakiuchi, Masatoshi Nakanishi, Mitsugi Senda
    1988 Volume 61 Issue 6 Pages 1845-1851
    Published: 1988
    Released: June 27, 2006
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    The conditions for obtaining the electrocapillary curves of the dilauroylphosphatidylcholine (DLPC) monolayer formed at the polarized nitrobenzene–water interface have been studied using the pendant drop method. To facilitate the measurement, the system for the interfacial tension measurement, including the computer software for the data handling, has been developed based on digital image processing of the video image of a pendant drop. The 95% confidence interval of the measured interfacial tension value was ±0.06 mN m−1. The time required to measure an electrocapillary curve with 30 points was 30 min, while the time necessary to convert the image data to the interfacial tension was 1 min. The potential drop across the monolayer has been demonstrated to influence the stability of the monolayer strongly. The DLPC markedly lowered the interfacial tension by forming a stable monolayer when the interface was polarized so that the aqueous phase has a negative potential with respect to the nitrobenzene phase. On the other hand, when the aqueous phase became positively polarized, the adsorbed DLPC molecules started to desorb from the interface, giving rise to the disruption of the monolayer. The electrocapillary curves only in the former potential range were found to be thermodynamically meaningful.
  • Hideaki Fujiwara, Ikuji Ohtaku, Tatsuya Takagi, Saburo Murata, Yoshio ...
    1988 Volume 61 Issue 6 Pages 1853-1856
    Published: 1988
    Released: June 27, 2006
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    The entropy of solution was measured by gas-liquid chromatography for the alkanes from pentane to decane in dibutyl phthalate solution. The results are discussed in relation to the Wertz-type equation, which correlates the entropy of solution with the thermodynamic third-law entropy of the solute, and to the scaled particle theory. A scaled particle treatment assuming non-spheres(spherocylinders) is shown to give improved results and to be promising in reproducing the experimental values of the entropy of solution, whereas the same treatment of spheres failed to explain the trend in the experimental values.
  • Masakatsu Yonese, Kazuhiko Baba, Hiroshi Kishimoto
    1988 Volume 61 Issue 6 Pages 1857-1863
    Published: 1988
    Released: June 27, 2006
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    Rheological properties of Alginate (Alg) gels were studied by measuring tensile stresses under small strains. The Alg gel rods were prepared in CaCl2, SrCl2, BaCl2, and Pb(NO3)2 solutions in the range of 0.03–1.0 mol dm−3. Their stresses showed long relaxation processes. By curve fitting method, equilibrium elastic moduli Ge, spontaneous elastic moduli Ge+Gr and relaxation times τ were obtained. The results Ge were independent of strains γ, and Gr and τ increased as increasing γ. The effects of Ca ion concentrations CCa on the elasticities were discussed by taking account of the ratio of Ca ion bindings obtained by dialysis equilibrium and that of junction formation obtained by circular dichroism. The values of Ge were analyzed by the theory of swollen gels. The number of the junctions was found to be constant in the region of CCa>0.03 mol dm−3, and slight increases of Ge to be due to changes of the water content and the density of the Alg gels. The magnitudes of Ge and Gr depended on the kind of counterions, and decreased in the order, Ba->>Ca->Sr-> PbAlg; this was almost the same as that of the ion selectivities.
  • Nobuyoshi Imaoka, Sadamu Takeda, Hideaki Chihara
    1988 Volume 61 Issue 6 Pages 1865-1872
    Published: 1988
    Released: June 27, 2006
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    Two kinds of motions of proton in dimeric carboxyl group were distinguished by the temperature dependence of spin-lattice relaxation times of dipolar system (T1d) and of Zeeman system (T1z) on acethylenedicarboxylic acid (ADCA) and on p-nitrobenzoic acid (PNBA) in the A2⁄a form. High temperature motion of ADCA is 180° rotation of the eight-membered ring of dimeric carboxyl group about the axis nearly parallel to the hydrogen bonds. The activation energy of this motion of ADCA is 58 kJ mol−1. The low temperature motion of ADCA and PNBA is the proton translation along the hydrogen bonds in a dimeric carboxyl group, which induces the minima of T1z and T1d at the same temperature. The activation energy derived from the high temperature slope of T1z curve is 6.9 kJ mol−1 for ADCA and 2.5 kJ mol−1 for PNBA. The low temperature slope gives a small activation energy of 1.9 kJ mol−1 for ADCA and 1.0 kJ mol−1 for PNBA. The frequency dependence of T1z in the low temperature limit was constant at low Larmor frequency. This result indicates that the translational motion of protons along the hydrogen bonds is not classical but quantum-mechanical.
  • Tetsuo Moriya
    1988 Volume 61 Issue 6 Pages 1873-1886
    Published: 1988
    Released: June 27, 2006
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    The excited-state reactions of 7-hydroxycoumarin (7HC) and 7-hydroxy-4-methylcoumarin (7H4MC) have been studied by measuring the absorption and fluorescence spectra in aqueous and organic solvents under acidic and basic conditions. Based on the solvent-dependent fluorescence of the fluorophores, the solvents could be classified into several groups: hydroxylic solvents, nonhydroxylic solvents with low dielectric constants, and those with high dielectric constants. In the hydroxylic solvent, protonation, deprotonation, and tautomerization were the main reactions, while in the nonhydroxylic solvent the formation of hydrogen bonding and ion pairs was essential. The fluorescence in water–ethanol mixtures and in aqueous sodium dodecyl sulfate solutions has also been examined in relation to the solvent-dependent spectra in pure hydroxylic and nonhydroxylic solvents.
  • Yosuke Yoshimura, Masaru Nakahara
    1988 Volume 61 Issue 6 Pages 1887-1892
    Published: 1988
    Released: June 27, 2006
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    The effect of the perturbation due to attractive solute–solvent and solvent–solvent interactions on the partial molal volume (PMV), entropy (PME), and enthalpy in infinitely dilute solution has been formulated on the basis of the first-order perturbation theory which comes from the van der Waals picture of liquid. PMV is found to be composed of the two compensating factors which arise from the solute–solvent and solvent–solvent attractive interactions treated as the perturbation; when the former is larger than the latter PMV becomes smaller. PME is influenced only indirectly by the attractive perturbation through the volume change due to the perturbation interactions. The limitations of the basic expressions derived are discussed in the case of large solute.
  • Takashi Sumiyoshi, Meiseki Katayama, Wolfram Schnabel
    1988 Volume 61 Issue 6 Pages 1893-1897
    Published: 1988
    Released: June 27, 2006
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    The reduction of 1-ethoxy-2-methylpyridinium (EMP+) ions in aqueous solution at room temperature by eaqand · CO2 was investigated in a pulse radiolysis study (irradiation with 10 ns pulses of 45 MeV electrons). For comparison, experiments with 1-methylpyridinium (MP+) and unsubstituted pyridinium (PH+) ions were carried out. With MP+ and PH+ the spectra of pyridinyl radicals were observed at the end of the pulse. In the case of EMP+ the spectrum of the pyridinyl radical was not detectable. However, a new absorption band at 340 nm was formed with a significant delay after the reduction. Therefore, it was concluded that pyridinyl radicals formed by reduction of EMP+ decompose very quickly into picoline and ethoxyl radicals. The latter add to EMP+ with a rate constant k=6×107 dm3 mol−1 s−1. The transient absorption band at 340 nm is ascribed to the adduct.
  • Masayoshi Aoki, Chiyoko Nakazato, Takahiro Masuda
    1988 Volume 61 Issue 6 Pages 1899-1902
    Published: 1988
    Released: June 27, 2006
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    The γ-radiolysis of water adsorbed on synthetic zeolite, MS 13X (Molecular Sieve 13X), has been investigated by the product analysis method using gas chromatography. One of the main products is molecular hydrogen, the G value of which increases with increasing amount of water adsorbed on MS 13X and reaches a first plateau (0.42) at ca. 4 mmol of water per g of MS 13X. At ca. 6 mmol g−1 of water, it resumes the increase and finally approaches a second plateau (1.2) at ca. 9 mmol g−1. The formation of hydrogen is depressed by an electron scavenger, while ammonia, a scavenger of positive hole, enhances the hydrogen formation. The result indicates that hydrogen is produced through a reaction of water with electrons generated in MS 13X. The rate constant for the reaction of electrons with water adsorbed on MS 13X is estimated to be (2.6±0.3)×108 dm3 mol−1 s−1, on the assumption that rate constants for reactions of electrons with some electron scavengers determined in liquid cyclohexane can be applied to this system.
  • Hisashi Togashi, Norimichi Kojima, Toshiro Ban, Ikuji Tsujikawa
    1988 Volume 61 Issue 6 Pages 1903-1909
    Published: 1988
    Released: June 27, 2006
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    The optical absorption spectra of the Mn2+ ion in MnM(edta)·6H2O (M=Zn, Cu, Ni, and Co) were measured at low temperature. Fine structural bands corresponding to the 6A1g4T2g (D) and 6A1g4A1g, 4Eg (G) transitions were found. The fine structure corresponding to the 6A1g4A1g, 4Eg (G) transition in the Zn compound were analyzed with the ligand field theory and the assignment of the absorption peaks was performed. Although the spectra of the Zn, Cu, and Co compounds are similar, those of the Ni compounds show significant broadening, which is possibly due to the energy transfer caused by the overlapping of the absorption bands of the Ni2+ and Mn2+ ions.
  • Keiichi Moriya, Takasuke Matsuo, Hiroshi Suga
    1988 Volume 61 Issue 6 Pages 1911-1916
    Published: 1988
    Released: June 27, 2006
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    The heat capacities of RbNO2 crystal have been measured between 15 and 330 K. Two phase transitions were found at (264.04±0.06) K and (83.8±0.2) K. The enthalpy and entropy of transition are (9310±450) J mol−1 and (35.9±1.8) JK−1 mol−1 for the former and (48±5) J mol−1 and (0.58±0.05) JK−1 mol−1 for the latter. The entropy of the high temperature transition was interpreted in terms of the orientational disorder of the NO2 ion. The dielectric constant increased from 6 to 10 as the transition temperature 264.04 K was traversed from below, indicating the increased motional freedom of the polar anion in the high temperature phase.
  • Katsuharu Tanaka, Kinichi Kasasaku, Hiroko Shimada, Ryoichi Shimada
    1988 Volume 61 Issue 6 Pages 1917-1923
    Published: 1988
    Released: June 27, 2006
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    Assignments of the normal vibrations of 2,6-dichloro-, 2,6-dibromo-, 3,5-dichloro-, and 3,5-dibromopyridines were made based on the polarization behavior of the Raman and infrared spectra in single crystals and the normal coordinate calculations. The effect of halo-substitution on the vibrational frequencies of the normal modes was discussed.
  • Toshiro Saito, Yoshinori Hirata, Hisashi Sato, Toshikatsu Yoshida, Nob ...
    1988 Volume 61 Issue 6 Pages 1925-1931
    Published: 1988
    Released: June 27, 2006
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    The external magnetic field effect on the lifetime of the ion pair state has been examined for the porphyrinmethylviologen combined systems in polar solvents by using nanosecond laser flash photolysis techniques. Applying the external magnetic field, a drastic increase in the lifetime has been observed. For PllMV2+ in DMSO under the magnetic field of 50 mT, the ion pair lifetime was almost three times longer than the zero field value, which can be deemed the ideal case of the external magnetic field effect due to the hyperfine interaction mechanism. The results clearly showed that the long-lived ion pair was formed by the intramolecular electron transfer from the triplet state of porphyrin.
  • Tamaki Maeda, Iwao Satake
    1988 Volume 61 Issue 6 Pages 1933-1937
    Published: 1988
    Released: June 27, 2006
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    The activities of the surfactant ion, counter ion, and co-ion in micellar solutions of dodecyltrimethylammonium chloride (DTAC) in the presence of NaCl were determined by using ion-selective electrodes. An application of the charged phase separation model gave an apparent degree of counter ion association to the micelle of 0.68 regardless of the salt concentration. A tentative estimation of the intermicellar concentrations of surfactant ion and counter ion was made on the basis of an assumption that the activity coefficients of the monomeric surfactant ion and co-ion were identical with each other. In the concentration range above the critical micelle concentration (cmc), the intermicellar concentration of the surfactant ion decreased gradually with increasing surfactant concentration, whereas the reverse was found for that of counter ion. Similar behaviors were also found for the activity coefficients of these ions. However, an increase in salt concentration caused a successive decrease in the concentration dependences of intermicellar concentrations as well as activity coefficients. Measurements were also made with the fluorescence decay curves of micelle-solubilized pyrene. An analysis based on the knowledge of the intermicellar concentration of surfactant ion estimated above revealed that the micelle aggregation number of DTAC remained virtually constant over wide concentration range above the cmc.
  • Kazuaki Harata
    1988 Volume 61 Issue 6 Pages 1939-1944
    Published: 1988
    Released: June 27, 2006
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    Crystal structures of heptakis(2,6-di-O-methyl)-β-cyclodextrin complexes with p-iodophenol and p-nitrophenol were determined by the X-ray analysis. These two crystals were isomorphous with the space group P212121 and cell dimensions: a=14.796(3), b=18.853(5), and c=28.989(6) Å for the p-iodophenol complex, and a=14.779(2), b=18.965(3), and c=28.741(4) Å for the p-nitrophenol complex. The structures were solved by the heavy atom method combined with the phase refinement by the tangent formula and refined by the blockdiagonal least-squares method to the R-values of 0.12 (p-iodophenol complex) and 0.10 (p-nitrophenol complex). The host molecule has a round shape, which is maintained by the intramolecular hydrogen bonds between the O(3)H hydroxyl group and O(2)CH3 methoxyl group of the adjacent residue. The guest molecules in the both complexes are not included within the host cavity but located in the intermolecular space between host molecules. The host cavity includes water molecules and a methoxyl group of the adjacent host. Hydrogen bonds are formed only within the host cavity.
  • Yutaka Hirashima, Katsuhiko Nishiwaki, Akihiko Miyakoshi, Hideyasu Tsu ...
    1988 Volume 61 Issue 6 Pages 1945-1951
    Published: 1988
    Released: June 27, 2006
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    A relationship between acid amounts over TiO2–ZrO2 catalysts and their activities for nonoxidative dehydrogenation of ethyl benzene to styrene was examined. The catalysts were prepared by two different methods; one is simultaneous hydrolysis of Ti and Zr mixed alkoxides solution and the other is physical mixing of pure TiO2 and ZrO2. The former consists of fine TiO2 and ZrO2 particles and is expected a lot of Ti–O–Zr bonding between the fine particles, while the latter is composed of large particles and less amounts of Ti–O–Zr bonding might be expected. Although the Ti–O–Zr bonding has been considered to generate a new acid site and to enhance the rate of dehydrogenation of ethylbenzene, the acid amounts and the rates observed on unit surface areas of both catalysts were not significantly different. On the basis of these results, the role of Ti–O–Zr bondig in TiO2–ZrO2 catalyst for dehydrogenation of ethylbenzene is discussed.
  • Yonezo Maeda, Masahiro Tomokiyo, Kenji Kitazaki, Yoshimasa Takashima
    1988 Volume 61 Issue 6 Pages 1953-1958
    Published: 1988
    Released: June 27, 2006
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    The effects of metal dilution and adsorption on the surface of silicon dioxide on the spin-crossover behavior of [Fe(acpa)2]PF6, [Fe(acpa)2]BPh4, and [Fe(bzpa)2]PF6, which undergo fast spin-state interexchange on the 57Fe Mössbauer timescale have been studied by using 57Fe Mössbauer and EPR spectroscopies, powder X-ray diffraction and magnetic susceptibility, where Hacpa is N-(1-acetyl-2-propylidene)-2-pyridylmethylamine and Hbzpa N-(1-benzoyl-2-propylidene)-2-pyridylmethylamine. Solid solution compounds, [FexCo1−x(acpa)2]BPh4(x=0.035 and 0.074) and [Fe0.05Co0.95(bzpa)2]PF6 exhibit spin-crossover phenomena. No difference in the spin-state interexchange rate is observed between the diluted compound and the corresponding undiluted one as far as the rates are evaluated by Mössbauer spectroscopy. Mössbauer spectra for [Fe0.074Co0.926(acpa)2]PF6 exhibit only a pair of quadrupole doublets assigned to the low-spin state in the temperature range from 78 to 298 K. The spin-state interexchange rates for [Fe(acpa)2]BPh4 and [Fe(bzpa)2]PF6 adsorbed on the surface of silicon dioxide become slow compared to those for the corresponding pure complexes and the narrowing of the spin-state transition temperature range is observed. On the contrary no detectable differences in the spin-state interexchange rates are observed between the Mössbauer spectra for [Fe(acpa)2]PF6 adsorbed on the surface of silicon dioxide and that for the pure complexes. These observations are interpreted in terms of a spin-state transition behavior in these complexes which is affected by the packing state in the solid state, which is dependent on the characteristic structure of the respective complex.
  • Zhi-Ping Bai, Hisahiko Einaga, Jinsai Hidaka
    1988 Volume 61 Issue 6 Pages 1959-1965
    Published: 1988
    Released: June 27, 2006
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    The coordination reaction of 8-hydroxy-7-[(2-hydroxy-5-carboxyphenyl)azo]-5-quinolinesulfonic acid (hcqs) to aluminum(III) has been investigated spectrophotometrically in a weakly acidic aqueous solution (pH 2–5) with 0.1 mol dm−3 NaCl at 22.0 °C; the thermodynamic stability, kinetics, and mechanism of the formation of the aluminum(III) complex were deduced. The ligand rapidly coordinates to aluminum(III), with its 8-quinolinol (ON) moiety, to form a yellow complex (metal:ligand=1:1), and then the complex slowly changes, via an intramolecular rearrangement, to a red complex with its dihydroxyazo (O-N-O) moiety, thus showing a linkage isomerism. In the first coordination process, the complex is formed mainly via a pathway of the reaction of AlOH2+ with Hhcqs3−. The coordination reaction mechanism of aluminum(III) with related ligands, 4-hydroxy-3-[(2-hydroxy-5-carboxyphenyl)azo]-1-naphthalenesulfonic and 7-[(4-carboxyphenyl)azo]-8-hydroxy-5-quinolinesulfonic acid, is also discussed.
  • Terufumi Fujiwara, Yoshiharu Okamoto, Yuroku Yamamoto
    1988 Volume 61 Issue 6 Pages 1967-1973
    Published: 1988
    Released: June 27, 2006
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    Rates of racemization of the tris(1,10-phenanthroline)iron(II) cation, [Fe(phen)3]2+, have been measured at 7.5 °C to 17.5 °C in 1,2-dichloroethane, o-dichlorobenzene, nitrobenzene, and nitromethane, and in 1,2-dichloroethane solutions containing dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), methanol (MeOH), acetone (Ac), and acetonitrile (AN). In the four pure solvents, the observed racemization rates are markedly smaller than those calculated by the Van Meter and Neumann equation, which relates the racemization rate to the solvation energy of the phen ligands and viscous resistance. Addition of donor solvents to 1,2-dichloroethane solutions of the iron complex enhances the racemization rates. The degree of enhancement increases in the order AN<Ac<MeOH<DMF<DMSO and the activation energy decreases in the same order. This sequence lies in the order of increasing Gutmann donor number of the solvents, indicating a nucleophilic interaction of the solvents with the iron metal in the transition state. These obsevations may be interpreted in terms of Kepert’ s model for solvent-assisted racemization of tris-chelated complexes and the molecular structure of a solvate complex determined previously, and allow us to modify the Van Meter and Neumann equation.
  • Takeshi Yamamura
    1988 Volume 61 Issue 6 Pages 1975-1978
    Published: 1988
    Released: June 27, 2006
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    [Ni3(SEt)8]2− reacted with water in acetone to give the known hexameric ring compound, [Ni(SEt)2]6, where SEt means CH3CH2S. The [Ni(SEt)2]6 was oxidized electrochemically in a quasi-reversible manner at +0.60 V (vs. SCE) in CH2Cl2. 1H and 13C NMR revealed that this compound has two types of –SEt (low- and high- field types; the chemical shift discrepancy is ca. 0.4 ppm for 1H NMR), probably corresponding to the axial–equatorial configurations of the thiolate. The formation of the cyclic hexamer in CH3CN and CHCl3 in the presence of protic reagents was studied.
  • Satoru Fujitsu, Hiroshi Toyoda, Kunihito Koumoto, Hiroaki Yanagida, Ma ...
    1988 Volume 61 Issue 6 Pages 1979-1983
    Published: 1988
    Released: June 27, 2006
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    Changes in electrical conductivity and the amount of adsorbed oxygen in porous ZnO were measured simultaneously in the temperature range of 200–600 °C. The saturated amount of adsorbed oxygen increased initially, went through a maximum at 500 °C, and then decreased with increasing temperature. The conductivity decreased exponentially with increase in the amount of adsorbed oxygen, which indicates that the energy barrier formed due to the chemisorbed oxygen controls the total conductivity. In a high temperature region, not only the chemisorbed oxygen, but also the oxygen diffused into the grain boundaries played important roles in changing the electrical conductivity. The diffused oxygen was examined by means of a depth profile of tracer 18O measured by SIMS. The formation of the energy barrier at the grain boundary was confirmed by current-voltage characteristic measurements.
  • Yasumasa Sakakibara, Fumio Okuda, Akira Shimobayashi, Kunihiko Kirino, ...
    1988 Volume 61 Issue 6 Pages 1985-1990
    Published: 1988
    Released: June 27, 2006
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    The cyanation of chlorobenzene catalyzed by Ni(PPh3)n, which was generated in situ from NiBr2(PPh3)2–Zn–PPh3(Ni : Zn : P=1 : 3 : 2 molar ratio), was at first examined with various MCN (M=K, Na)–solvent systems by three procedures in order to clarify the conditions under which the reaction occurs. The effects of the systems and the procedures on the reaction were remarkable. It was observed that the cyanide ion has an inhibitory action on both the reduction of Ni(II) and the oxidative addition of the halide to Ni(0). However, when such MCN–dipolar aprotic solvent systems as KCN–HMPA, KCN or NaCN–MeCN, which give low cyanide concentrations, were used, the reaction readily took place at 50–60 °C without reducing Ni(II) prior to the addition of MCN and adding MCN slowly. Various Y-substituted chlorobenzenes, except for those with Y=o-Cl, o-CN, and m-NO2, were cyanated to give the corresponding nitriles in fair to good yields. NiBr2–PPh3 can be used in place of NiBr2(PPh3)2 if MCN is added after reduction. In addition, less reactive halides, such as o-dichlorobenzene and o-chlorobenzonitrile, were fairly smoothly cyanated by the use of NiBr2–1,1′-bis(diphenylphosphino)ferrocene.
  • Michiharu Kato, Yukio Matsumura, Kiyoshi Heima, Akira Yoshikoshi
    1988 Volume 61 Issue 6 Pages 1991-1998
    Published: 1988
    Released: June 27, 2006
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    11-Acetoxy-12bα-methoxymethyl-4,4,6aα,9-tetramethyl-1,2,3,4,4aα,5,6,6a, 12aβ,12b-decahydro-12H-benzo[a]xanthene (34), which has been expected as a promising key intermediate for the synthesis of siccanin (1), was synthesized via acid-catalyzed cyclization of 1α-(2-hydroxy-6-methoxy-4-methylbenzyl)-8aα-methoxymethyl-2,5,5-trimethyl-1,4,4aα,5,6,7,8,8aα-octahydronaphthalene (13) and isomeric exo olefin 21. The phenol acetate 34, however, was so resistant to oxidation that no corresponding 12-oxo derivative, which was expected to provide 11-acetoxy-12bα-acetoxymethyl-12-oxo-4,4,6aα,9-tetramethyl-1,2,3,4,4aα,5,6,6a,12aα,12b-decahydro-12H-benzo[a]xanthene (4) on epimerization at its C(12a) position as well as hydrofuran ring formation at the C(12) position with its angular methoxymethyl substituent, was obtained.
  • Hideo Suzuki, Koichi Mochizuki, Tatsuya Hattori, Noriyuki Takahashi, O ...
    1988 Volume 61 Issue 6 Pages 1999-2005
    Published: 1988
    Released: June 27, 2006
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    Acrylates, crotonate, and fumarates derived from cinchona alkaloids were easily prepared. The highly re-facial selective additions of the dienophiles derived from cinchonidine or quinine to some dienes were achieved in the presence of SnCl4. Similarly, si-facial selective additions were also achieved by the use of cinchonine instead of cinchonidine or quinine as a chiral auxiliary alcohol with equal ease. The inverse diastereofacial selectivity was observed by the use of TiCl4 instead of SnCl4 as a Lewis acid in the case of the reaction of the acrylates cited above with cyclopentadiene. It was suggested by the infrared spectra of the dienophile–SnCl4 complexes and by some circumstantial evidence that in the complexes, SnCl4 coordinates with the oxygen atom of the C–O bond (not C=O bond) and probably also with the nitrogen atom of the quinuclidine framework to form a rigid five-membered ring structure.
  • Shinji Takeoka, Etsuo Hasegawa, Hiroyuki Ohno, Eishun Tsuchida
    1988 Volume 61 Issue 6 Pages 2007-2012
    Published: 1988
    Released: June 27, 2006
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    1,3-Bis(2,4-octadecadienoyl)-rac-glycero-2-phosphorylcholine (1,3-DPC), polymerizable lipid which contains diene groups in both 1- and 3-acyl chains, was polymerized as liposomes in an aqueous medium. Polymerization was initiated by water-insoluble azobis(isobutyronitrile) (AIBN) or water-soluble azobis(2-amidinopropane) dihydrochloride (AAPD). AIBN was mixed with the monomeric lipids and the mixture was dispersed in an aqueous medium by sonication to facilitate transfer of AIBN into monomeric lipid liposomes. On the other hand, AAPD was simply added to the liposome suspension. The 1,3-DPC liposomes were easily polymerized by the addition of either water-soluble AAPD or water-insoluble AIBN to give polymerization conversion of over 80% in both cases. No selective polymerization of diene groups in the different acyl chains was found in 1,3-DPC liposomes whereas the selective polymerization was clearly seen in 1,2-bis(2,4-octadecadienoyl)-sn-glycero-3-phosphorylcholine (DODPC). Polymerized 1,3-DPC liposomes were not soluble in organic solvent suggesting the formation of crosslinked bilayer structure. The obtained results suggested that the diene groups in both 1- and 3-acyl chains were almost equivalent and located in the interface between an aqueous phase and hydrophobic region. Polymerized liposomes thus prepared were stable against heating, detergent attack and even methanol washing. Copolymerization of mixed liposomes composed of 1,3-DPC and DODPC (5:1) revealed that the AIBN or AAPD initiated polymerization conversion of DODPC reached about 68%. 1,3-DPC is considered to be radical propagation transfer between diene groups in 1- and 2-acyl chains of DODPC during polymerization.
  • Yoshio Aso, Koji Yui, Takanori Miyoshi, Tetsuo Otsubo, Fumio Ogura, Ji ...
    1988 Volume 61 Issue 6 Pages 2013-2018
    Published: 1988
    Released: June 27, 2006
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    Three new electron donors, 5,6-dihydroacenaphtho[5,6-cd]-1,2-dithiole (1a), -diselenole (1b), and -ditellurole (1c) have been prepared with a view to developing new electron donors for low-dimensional molecular complexes. Their donor characters are markedly enhanced as compared with the corresponding dichalcogen-bridged naphthalenes. They formed charge-transfer complexes with tetracyanoquinodimethane (TCNQ). Their electrical conductivities increase in the order of polarizable chalcogen. The crystal structures of 1a–TCNQ complex and neutral 1c were determined by X-ray analyses. In the crystal, 1a and TCNQ form a unique mixed stack, that is, a pair of donors and a pair of acceptors make an alternately stacking column. Neutral 1c takes an almost planar conformation and molecules are connected to each other with strong Te–Te interactions.
  • Tateo Nakamori, Toshiyuki Saito, Toshiyasu Kasai
    1988 Volume 61 Issue 6 Pages 2019-2023
    Published: 1988
    Released: June 27, 2006
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    Tetracyclic compounds with a thiazolidinone or thiazinone ring fused to 1H-naphth[2,3-d]imidazole-4,9-dione were synthesized. Dimethyl 2-(4,9-dioxo-4,9-dihydronaphth[2,3-d]imidazol-2-ylthio)fumarate (3) was obtained by a reaction of 2,3-dihydro-2-thioxo-1H-naphth[2,3-d]imidazole-4,9-dione with dimethyl acetylenedicarboxylate in methanol. A ring-closure reaction of 3 in acetic anhydride was found to give selectively methyl (3,5,10-trioxo-2,3,5,10-tetrahydronaphth[2′,3′ : 4,5]imidazo[2,1-b]thiazol-2-ylidene)acetate, while, the cyclization of 3 in polyphosphoric acid afforded methyl 4,6,11-trioxo-6,11-dihydro-4H-naphth[2′,3′ : 4,5]imidazo[2,1-b]thiazine-2-carboxylate.
  • Osamu Uchikawa, Nobuhisa Okukado, Toshiie Sakata, Koichi Arase, Kenji ...
    1988 Volume 61 Issue 6 Pages 2025-2029
    Published: 1988
    Released: June 27, 2006
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    Two endogenous γ-lactones, 3-hydroxy-4-butanolide (1) and 2-hydroxy-4-hydroxymethyl-4-butanolide (2) have been identified as substances that enhance, respectively, satiety and hunger by their effects on the feeding behavior and the central neurons of rats. To determine the stereochemistry of the physiologically active isomers, all the stereoisomers of these two lactones were synthesized and their effects on the feeding behavior and humoral factors were assessed by infusion into the rat third cerebroventricle. Among four isomers, (2S,4S)-2-hydroxy-4-hydroxymethyl-4-butanolide (2a) was most effective in elicitating the feeding and caused potent hypoglycemia with hyperinsulinemia. (S)-3-Hydroxy-4-butanolide (1a) suppressed the food intake more potently than the antipode and caused humoral responses reciprocal to those of 2a. From these facts, it was concluded that 1a and 2a are physiologically active forms for conveying intrinsic signals of satiety and hunger to neurons in the hypothalamus.
  • Hajime Satonaka, Kazuhisa Abe, Minoru Hirota
    1988 Volume 61 Issue 6 Pages 2031-2037
    Published: 1988
    Released: June 27, 2006
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    The predominance of planar C–H/O=C approached conformations in methyl 3-formyl-2-, 2-formyl-3-, and 4-formyl-3-thiophenecarboxylates was shown experimentally by the chemical shifts of the formyl protons, the unusually large 1JCH values of the formyl groups, and their infrared C–H and C=O absorptions. The stability of the C–H/O=C approached conformation was attributed to the hydrogen-bond-like interaction between the two groups. The considerably large positive bond population between non-bonded H/O and the additional charge separation indicated by the MNDO calculations supported the presence of the intramolecular hydrogen bond.
  • Yasuhiro Tanoue, Akira Terada
    1988 Volume 61 Issue 6 Pages 2039-2045
    Published: 1988
    Released: June 27, 2006
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    Oxidative demethylation of 2-(α-hydroxyalkyl- and α-oxoalkyl)-1,4,5,8-tetramethoxynaphthalene with (NH4)2Ce(NO3)6 gave two isomeric dimethoxynaphthoquinones: 2-substituted and 6-substituted 5,8-dimethoxy-1,4-naphthoquinones. Further demethylations of the former isomers to the corresponding dihydroxynaphthoquinones required an AgO–40%HNO3 reagent, while the latter isomers needed AlCl3 as the demethylation reagent. Some comments regarding the mechanism of these oxidative demethylations with (NH4)2Ce(NO3)6 are given.
  • Kazuo Yamaguchi, Shigeto Negi, Shohei Kozakai, Roichi Nagano, Hitoshi ...
    1988 Volume 61 Issue 6 Pages 2047-2054
    Published: 1988
    Released: June 27, 2006
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    ω-Hydroxy carboxylic acids (3, 5, 6, 7, 10, 12, 14, 17, 18, 20, and 22) bearing 2–6 ether oxygens and aromatic rings with or without a tetrahydrofuran ring and the ω-methoxy and ω-benzyloxy derivatives of 5 (8 and 9) were synthesized. These were employed as carriers for active and competitive transport of alkali metal ions through liquid membrane as well as for extraction of alkali metal ions to organic layers. Effect of hydrophobic group of aromatic and tetrahydrofuran rings, number of ether oxygens, and terminal hydroxyl group of the ionophores on the ion transport ability and selectivity were investigated. The hydrophobic groups increased total amount of transported ions as well as partition coefficients. The ionophore, 5, which contains five ether oxygens, two aromatic rings, and o-toluic acid moiety transported K+ selectively over Na+ and Li+ through 1,2-dichloroethane being consistent with the extraction experiments. The m- and p-substituted isomers, 6 and 7, exhibited no transport ability through 1,2-dichloroethane. The ω-alkoxy derivatives of 5 (8 and 9) exhibited less selectivity for K+ through 1,2-dichloroethane than 5 did. Through 1-hexanol, the ionophores, 5–9, including linoleic acid with no ether linkage transported alkali metal ions. The ionophores (3, 12, 20, and 22) containing 2–4 ether oxygens did not exhibit high transport ability.
  • Akikazu Kakehi, Suketaka Ito, Naosumi Kinoshita, Yukio Abaka
    1988 Volume 61 Issue 6 Pages 2055-2061
    Published: 1988
    Released: June 27, 2006
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    The alkaline treatment of 1-[(substituted benzylthio)methyleneamino]pyridinium and 1-[2-(substituted benzylthio)vinyl]pyridinium bromides possessing an electron-withdrawing substituent such as a nitro or cyano group in the presence or absence of a dehydrogenating agent afforded the corresponding 3-arylpyrazolo[1,5-a]pyridines and 1-arylindolizines in moderate to good yields, while the reactions of the parent pyridinium salts and those having an electron-releasing group did not produce any significant products. The mode of the reaction, a ring contraction-desulfurization, is the same as that observed in related monocyclic species.
  • Masahiro Minabe, Keisuke Isozumi, Ken-ichi Kawai, Masaaki Yoshida
    1988 Volume 61 Issue 6 Pages 2063-2066
    Published: 1988
    Released: June 27, 2006
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    Photocarboxylation of 4H-cyclopenta[def]phenanthrene by carbon dioxide in the presence of N,N-dimethylaniline in dimethyl sulfoxide afforded 8,9-dihydro-4H-cyclopenta[def]phenanthrene-8- and 2-carboxylic acid, and 4H-cyclopenta[def]phenanthrene-8-carboxylic acid. These acids were derived into methyl-4H-cyclopenta[def]phenanthrenes.
  • Masahiro Minabe, Masaaki Yoshida, Seiji Saito, Keisuke Tobita, Takashi ...
    1988 Volume 61 Issue 6 Pages 2067-2070
    Published: 1988
    Released: June 27, 2006
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    The thermal treatment of 1-bromo-2-(9-fluorenylidene)-1-phenylethylene afforded three different types of [2+2]cycloaddition products. The 1-tolyl homolog showed similar trends, but the chloro analog gave only two types. These results suggest that reactions of the rigid and bulky allenes take place through a 2,2′-biradical giving head-to-head, head-to-tail, and tail-to-tail adducts through the expected processes.
  • Eiji Yashima, Yoshio Okamoto, Koichi Hatada, Hiroyuki Kageyama, Nobuta ...
    1988 Volume 61 Issue 6 Pages 2071-2077
    Published: 1988
    Released: June 27, 2006
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    The molecular structures of α-methylbenzyl methacrylate, 1,2-diphenylethyl methacrylate, α-t-butylbenzyl methacrylate, 1,2,2,2-tetraphenylethyl methacrylate, diphenylmethyl methacrylate, and 1,1-diphenylethyl methacrylate in solution were investigated by means of IR spectroscopy and 1H NMR spectroscopy using a lanthanoid-induced chemical shift (LIS) reagent [Eu(fod)3] by reference to X-ray analysis data. The preferred conformation between the C=C double bond and the C=O group was estimated to be s-cis in solution. The conformation of ester groups of α-substituted benzyl methacrylates in toluene depended upon the α-substituent and the temperature. On the basis of structural data, the mechanism of the highly enantiomer-selective polymerization of racemic methacrylates with a (−)-sparteine-Grignard reagent complex is discussed.
  • Makoto Komiyama
    1988 Volume 61 Issue 6 Pages 2079-2082
    Published: 1988
    Released: June 27, 2006
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    Formations of 2- and 4-(hydroxymethyl)phenols from phenol and formaldehyde in aqueous alkaline solutions were kinetically investigated by the use of HPLC. The para/ortho ratio for the products sigmoidally increased with increasing concentration of sodium hydroxide, whereas the total yield of the (hydroxymethyl)phenols showed a steep maximum at the charged molar ratio unity of sodium hydroxide to phenol. Use of lithium hydroxide and potassium hydroxide, in place of sodium hydroxide, as alkaline catalysts results in almost the same para/ortho ratios. The addition of potassium chloride and magnesium sulfate decreased both the para/ortho ratio and the yield. These results indicate that the reactions proceed via an electrophilic attack of formaldehyde, which is free from the adduct formation with hydroxide ion, at phenolate ion. Electrostatic interactions between the phenoxide oxygen atom of the phenol and the incoming hydroxymethyl residues in the transition state exhibit a predominant role in the determination of the para/ortho ratio.
  • Yasuo Kikuchi, Kiyoshi Higashi, Nobuo Tamiya
    1988 Volume 61 Issue 6 Pages 2083-2087
    Published: 1988
    Released: June 27, 2006
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    The diastereomer ratio was analyzed on methionine S-oxide residues formed by in vivo posttranslational oxidation of methionine residues in a protein. The hinge-ligament protein of molluscan bivalves is distinct from usual proteins in containing a large amount of methionine S-oxide. The methionine S-oxide was released from the protein by proteolytic digestions and was found to be a mixture of approximately equall amounts of two diastereomers, (5S)- and (5R)-L-methionine S-oxide.
  • Kaoru Nakamura, Takehiko Miyai, Kazutoshi Ushio, Shinzaburo Oka, Atsuy ...
    1988 Volume 61 Issue 6 Pages 2089-2093
    Published: 1988
    Released: June 27, 2006
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    Various esters of 2-methyl-3-oxopropionic acid were subjected to the reduction with bakers’ yeast. Effects of size and bulkiness as well as hydrophobicity of alcohol moieties of the substrates on the enantioselectivity of the reduction were investigated. The substrates having bulky ester groups gave the (R)-hydroxy esters with high enantioselectivities. A mechanism to alter the stereoselectivity of the reduction is proposed.
  • Seiji Shinkai, Sayuri Kawanabe, Akito Kawase, Toshiro Yamaguchi, Osamu ...
    1988 Volume 61 Issue 6 Pages 2095-2102
    Published: 1988
    Released: June 27, 2006
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    In order to assess the effect of intramolecular acid catalysis on the specific flavin reactivities, 3-methyl-10-(2-hydroxyphenyl)isoalloxazine (1(2OH)) and 3-methyl-10-(2-hydroxy-1-naphthyl)isoalloxazine (2(2OH)) were synthesized and the redox properties were compared with those of reference flavins such as 3-methyl-10-(2-methoxyphenyl)isoalloxazine (1(2OMe)) and 3-methyl-10-(2-methoxy-1-naphthyl)isoalloxazine (2(2OMe)). The pKa values for 1(2OH) and 2(2OH) were determined to be 7.7 and 7.0, respectively, which were lower than that of 3-methyl-10-(4-hydroxyphenyl)isoalloxazine (1(4OH): pKa 8.6). It is thus unlikely that 2′-OH and N(1) form a hydrogen bond at the initial state of the reaction (i.e., at the oxidized state). The X-ray crystallographic studies indicated that the phenyl ring makes an angle of 79.7° with the isoalloxazine ring and the 2′-OH group forms a hydrogen bond with methanol included in the crystal lattice. In acetonitrile at 30 °C 1-benzyl-1,4-dihydronicotinamide was not oxidized by 1(2OMe), 1(4OH), and 2(2OMe). On the other hand, the oxidation took place with 1(2OH) and 2(2OH) which have an acidic OH group at the 2′-position of the 10-aryl substituent. The presence of the intramolecular acid catalysis suggests that 2′-OH and N(1) can interact at least at the transition state or at the final state of the reaction (i.e., at the reduced state). In general, the oxidized flavin adopts a “planar” structure which is sterically tense while the reduced flavin adopts a “bent” structure which is sterically relaxed. As the structure of the transition state is more or less similar to the reduced form, the hydrogen-bonding interaction could increase on going from the tense initial state to the relaxed transition state. This is a novel example for acid catalysis in flavin-mediated reactions.
  • Motoo Tori, Reiko Matsuda, Masakazu Sono, Yoshihiro Kohama, Yoshinori ...
    1988 Volume 61 Issue 6 Pages 2103-2108
    Published: 1988
    Released: June 27, 2006
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    Lupane-3β,28-diol, lupan-3β-ol, and friedelan-3β-ol were treated with m-chloroperbenzoic acid (mCPBA) in refluxing chloroform to afford corresponding lactones in one step, while lupane-3β,28-diyl diacetate, lupan-3β-yl acetate, and friedelan-3β-yl acetate to give hydroxylated or keto derivatives. Similar reaction of dendropanoxide with mCPBA yielded 6β-, 7β-, 21α-, and 22β-hydroxylated compounds.
  • Tsuyoshi Satoh, Ken-ichi Iwamoto, Atsushi Sugimoto, Koji Yamakawa
    1988 Volume 61 Issue 6 Pages 2109-2115
    Published: 1988
    Released: June 27, 2006
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    The α,β-epoxy sulfoxides 1 and 2 bearing ω-oxyalkyl group were synthesized from ω-oxyalkyl carbonyl compounds and 1-chloroalkyl phenyl sulfoxide. The intramolecular ring opening of the oxirane ring of these α,β-epoxy sulfoxides, through an attack of the terminal hydroxyl group, gave 2-acyl cyclic ethers or 3-keto cyclic ethers, including spiro-type cyclic ethers. This procedure is applicable to the preparation of five- and sixmembered cyclic ethers.
  • Toshiaki Matsuki, Nan Xing Hu, Yoshio Aso, Tetsuo Otsubo, Fumio Ogura
    1988 Volume 61 Issue 6 Pages 2117-2121
    Published: 1988
    Released: June 27, 2006
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    Bis(p-methoxyphenyl) telluride (1) electrochemically reacted with supporting electrolytes such as tetrabutylammonium acetate and tetraethylammonium tosylate under anhydrous conditions to give tellurium(IV) diacetate 2a and ditosylate 2b, respectively. On the other hand, 1 was electrolyzed in the presence of water to give telluroxide 3. It has turned out that the tellurium compounds 2a and 2b like telluroxide 3 are mild oxidizing agents, but 2b behaves differently in a reaction towards thioamide. Thus 2a and 3 converted it into nitrile, while 2b did it into 1,2,4-thiadiazole. An indirect electrolytic oxidation of thioamides with 1 as a mediator was examined under various conditions. As a result, nitriles or 1,2,4-thiadiazoles could be chemoselectively formed, depending on the intermediacy of 2a or 3 as an active species for the former and 2b for the latter.
  • Fuyuhiko Matsuda, Masako Ohsaki, Kaoru Yamada, Shiro Terashima
    1988 Volume 61 Issue 6 Pages 2123-2131
    Published: 1988
    Released: June 27, 2006
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    Preparation of some AB-ring systems 5 and 8 of sesbanimides 1 and 2, potent antitumor alkaloids, were performed starting from the synthetic intermediates of our first total synthesis of 1 and 2. The C-ring systems 14a–d were synthesized by applying the previously explored novel Reformatsky reaction to various aldehydes. The optically active BC-ring systems 20 and 21 having the same absolute configurations as those of 1 and 2, were derived from (−)-2,4-O-methylene D-sorbitol (15) as the B-ring synthon. Since all of these compounds 5, 8, 14a–d, 20, and 21 and the previously synthesized AB-ring system 3 showed no significant in vitro cytotoxicity against P388 murine leukemia, its appeared evident that 1 and 2 exhibit their notable antitumor activity owing to cooperation of the A- and C-rings.
  • Otohiko Tsuge, Shuji Kanemasa, Hiroyuki Suga
    1988 Volume 61 Issue 6 Pages 2133-2146
    Published: 1988
    Released: June 27, 2006
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    A new synthetic method of 2-(1-phosphorylalkyl)furans with a variety of substituents on the ring is presented. Cycloaddition of (diethoxyphosphoryl)acetonitrile oxide to O-protected allyl alcohols is followed by a simple sequential procedure including Raney Ni reduction and acid treatment to give 2-(1-phosphorylmethyl)furans. The phosphorus-stabilized carbanions derived from the phosphorus-functionalized furans are applied to alkylation, oxidation with oxygen, or olefination to provide 2-(1-phosphorylalkyl)furans, 2-acylfurans, or 2-(1-alkenyl)furans, respectively. Some other synthetic applications are also described.
  • Mitsuhiro Kinoshita, Masato Taniguchi, Masahiko Morioka, Hitoshi Takam ...
    1988 Volume 61 Issue 6 Pages 2147-2156
    Published: 1988
    Released: June 27, 2006
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    The title compound, (3S,4S,5S,9S,11R,12R,15R,17S)-4-[(t-butyldimethylsilyloxy)methyl]-1,3,5,9,11,12,15,17,19-nonahydroxy-3,5:11,12:15,17-tri-O-isopropylidene-19-O-(4-methoxybenzyl)-9-O-[(2-methoxyethoxy)methyl]-7-nonadecanone (1) was effectively synthesized through the coupling of (3S,5R,8R,9R,11S)-12-iodo-3,5:8,9-di-O-isopropylidene-1-O-(4-methoxybenzyl)-11-O-[(2-methoxyethoxy)methyl]-1,3,5,8,9,11-dodecanehexol (2) and (3S,4R,5S)-4-[(t-butyldimethylsilyloxy)methyl]-3,5-O-isopropylidene-1,1-bis(methylthio)-1-trimethylstannyl-6-heptene-3,5-diol (36). The C-13–C-19 segment 36 was enantiospecifically synthesized from 1,2:5,6-di-O-isopropylidene-α-D-thero-D-glycero-3-hexofuranosulose (7) via (2S,4R,5S)-5,6-epoxy-3-[(t-butyldimethylsilyloxy)methyl]-1-hexen-3-ol (6a) in 11.6% overall yield.
  • Motomitsu Kawai, Makoto Onaka, Yusuke Izumi
    1988 Volume 61 Issue 6 Pages 2157-2164
    Published: 1988
    Released: June 27, 2006
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    The Michael addition of silyl ketene acetals to α,β-unsaturated esters (enoates) is investigated. The reaction is catalyzed by clay montmorillonite (solid acid) most effectively among various, homogeneous and heterogeneous acid promoters. The montmorillonite-catalyzed reaction has several prominent features: (1) Not only α- or β-monosubstituted acrylates but also α,β- or β,β-disubstituted acrylates are applicable. (2) The highly regioselective 1,4-addition to a polyenoate is achievable. (3) The Michael adduct can be obtained in the form of a labile silyl ketene acetal owing to a simple work-up procedure. The Michael reaction of a silyl enol ether and silyl ketene acetals with α,β-unsaturated ketones (enones) is also described.
  • M. S. K. Niazi
    1988 Volume 61 Issue 6 Pages 2165-2170
    Published: 1988
    Released: June 27, 2006
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    The electrolytic conductance of LiClO4 has been determined in N,N-dimethylformamide (DMF) and its binary mixtures with acetone (Ac) and ethyl methyl ketone (MEK) at 25 °C. Ion association constants (KA) and limiting molar conductance (Λ0) were calculated from these data using Fuoss equation with modifications. The KA values of LiClO4 in these binary mixtures are interpreted in terms of solvent separated ion pairs while in pure Ac and MEK almost contact ion pairs are expected. A comparison is made for Λ0 and KA values of this salt in Ac and Ac–DMF mixtures with those obtained by Gill et al. Further, a comparison is made between these results and spectroscopically derived results by others in analogous media. LiClO4 has been found more associated in Ac–DMF solvent system than in the MEK–DMF mixed solvent system.
  • T. Ramanjappa, E. Rajagopal
    1988 Volume 61 Issue 6 Pages 2171-2173
    Published: 1988
    Released: June 27, 2006
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    The effect of 2-butanone on the temperature corresponding to adiabatic compressibility minimum (TACM), sound velocity maximum (TSVM) and specific acoustic impedance maximum (TSAIM) of pure water has been studied by experimentally determining the sound velocity and density of aqueous solution at different concentrations over a temperature range 34–70.5 °C. The structural contribution to the shift in TACM, TSVM, and TSAIM has been evaluated. The shift is positive throughout the concentration range studied and indicates that 2-butanone is hydrophobic in nature.
  • M. L. Srivastava, Bali Ram
    1988 Volume 61 Issue 6 Pages 2175-2179
    Published: 1988
    Released: June 27, 2006
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    Electrophoretic mobilities of progesterone particles dispersed in aqueous solutions of D-glucose and urea, in the concentration range 10−3–104 mol l−1 have been measured to investigate electrical properties of the interface. Zeta potentials have been determined for this purpose. The dependence of zeta potentials on concentration has also been examined. Theory of the electrical double layer has been used to explain the results.
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