Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
72 巻 , 4 号
選択された号の論文の30件中1~30を表示しています
  • Yoshio N. Ito, Tsutomu Katsuki
    原稿種別: Accounts
    1999 年 72 巻 4 号 p. 603-619
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Chiral metallosalen complexes have been recognized as one of the most promising catalysts for various asymmetric reactions. The studies on asymmetric epoxidation catalyzed by chiral (salen)manganese complexes will be reviewed at first. The enantioselectivities have reached to the level as high as 90—99% ee for the epoxidation of conjugated cis-di- and trisubstituted olefins by developing the second generation of chiral salen ligands. Although it has been proven by Freichtinger and Plattner that epoxidation proceeds through an oxo species, the mechanism of asymmetric induction is still surrounded by controversy. However, our recent studies have clarified that the conformation of the salen ligand in oxo(salen)manganese(V) species plays a very important role in determining the direction of the olefin’s access to the oxo species. This study led to the new finding that an achiral (salen)metal complex can be used as a chiral catalyst by regulating the conformation of achiral ligand. The appropriately modified (salen)manganese(III) complexes can also be applicable for asymmetric oxidation of enol ether derivatives, kinetic resolution of racemic allenes, enantioselective benzylic C–H oxidation, asymmetric desymmetrization of meso-heterocycles, and asymmetric oxidation of alkyl aryl sulfides. In the asymmetric aziridination of styrene derivatives by using PhI=NTs as a terminal oxidant, high enantioselectivity of up to 94% has been achieved by the further modification of the chiral (salen)manganese(III) complex. The chiral (salen)cobalt(III) complex is a good catalyst for asymmetric cyclopropanation of styrene derivatives and asymmetric S-ylide formation from allyl aryl sulfides, in which the resulting S-ylides undergo [2,3]-Wittig rearrangement in situ to produce chiral 2-(phenylthio)pentanoate derivatives.
  • Takakazu Yamamoto
    原稿種別: Accounts
    1999 年 72 巻 4 号 p. 621-638
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Various π-conjugated polymers have been obtained by using organometallic polycondensations mediated by organotransition metal complexes. For example, Ni(0) complex-promoted dehalogenation polycondensation of dihaloaromatic compounds X–Ar–X affords poly(arylene)s, Arn. Pd-catalyzed polycondensation gives poly(arylene–ethynylene)s, Ar–C≡C–Ar′–C≡Cn. These polymers are electrochemically active, electrically conductive, and light-emitting. Their well-characterized linear structure brings about unique packing of the polymer molecules in the solid. In this paper, we describe preparation by the organometallic polycondensations, basic properties, the ordered structure in the solid, and applications for electronic and optical devices of π-conjugated polymers.
  • Naoki Yoneyama, Akira Miyazaki, Toshiaki Enoki, Gunzi Saito
    原稿種別: Article
    専門分野: TP
    1999 年 72 巻 4 号 p. 639-651
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    We have investigated the magnetic properties of several TTF-based Mott insulators consisting of dimerized/trimerized-donor units, which are classified into three subgroups: (1) β′-(BEDT-TTF)2X (X = ICl2, AuCl2) and (BEDT-TTF)2GaCl4 as strong dimer systems, (2) α′-(BEDT-TTF)2IBr2 salt as a weak dimer system, and (3) (BMDT-TTF)3ClO4(1,2-dichloroethane) and (BMDT-TTF)3AsF6(1,1,2-trichloroethane) as weak trimer systems. The group (1) compounds have localized spin systems with an S = 1/2 localized spin per dimer unit. In group (2), weak dimerization produces a fractional magnetic moment, which reflects the delocalization of the electrons, although the magnetism is described in terms of an S = 1/2 low-dimensional antiferromagnet. The ClO4 salt in the group (3) indicates the existence of a localized spin per trimer, whereas the trimerization is quite weak, because the inter-trimer Coulomb interactions generate the charge disproportionation resulting in the localization of electrons. The absence of the charge disproportionation brings about the feature of fractional magnetic moments in the AsF6 salts.
  • Kiyofumi Murakami, Katsuyoshi Tsurufuji
    原稿種別: Article
    専門分野: TP
    1999 年 72 巻 4 号 p. 653-659
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    The binding of five dianionic azo dyes: disodium 3-hydroxy-4-(2,4,5-trimethylphenylazo or 1-naphthylazo)-2,7-naphthalenedisulfonate, disodium 6-hydroxy-5-(4-sulfonatophenylazo or 4-sulfonato-1-naphthylazo)-2-naphthalenesulfonate, and disodium 2-(2-hydroxy-1-naphthylazo)-5-(4-sulfonatophenylazo)benzenesulfonate, to hen egg white lysozyme has been studied by an equilibrium dialysis method at pH = 7.0 (0.1 mol dm−3 phosphate buffer) and 25 °C. The measured binding isotherms showed that all of these dyes cooperatively bind to the protein, but the degree of the cooperativity differs from dye to dye. From the result that the maximum binding number (6) was about half of those for monoanionic dyes, these dye molecules were found to bind bifunctionally with their two sulfonato groups to the cationic residue pairs on the protein. The binding isotherms were analyzed on the basis of the stepwise binding scheme by a nonlinear regression analysis, and all the binding constants have been evaluated. The differences in the cooperative-binding behavior between dyes have been examined from the viewpoints of the structural difference between dyes and of the distribution of cationic residues on the protein. It was found that the hydrophobicity of each ligand plays a central role for the cooperativity, and that the orientation of the hydrophobic part of ligand in bound state as well as the distribution of charged residues on the protein also affect the binding behavior.
  • Islam SM Saiful, Jun-ichi Fujisawa, Nagao Kobayashi, Yasunori Ohba, Se ...
    原稿種別: Article
    専門分野: TP
    1999 年 72 巻 4 号 p. 661-667
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Electron spin polarizations were studied for a system of excited triplet (T1) phthalocyanine (MTNPc; M = H2, Zn) and a nitroxide radical (TEMPO) in toluene solution by means of time-resolved EPR (TREPR) spectroscopy. TREPR spectra of the T1 state and the radical (R) were observed simultaneously. Spin polarizations of both signals were found to consist of two components with different decay rates. From analyses of the polarizations and the decay curves, it was found that the triplet polarizations are generated from anisotropic S1→T1 intersystem crossings and thermal populations. The initial and late polarizations on TEMPO were interpreted in terms of electron spin polarization transfer (ESPT) from T1 and a radical-triplet pair mechanism (RTPM) with a quartet precursor under J < 0 (J; exchange coupling parameter), respectively. The ESPT rate was determined and found to be dependent on temperature and the central atom(s) of MTNPc. In the H2TNPc system, the ESPT rate is much slower than the diffusion rate and axial ligation of TEMPO remarkably accelerates the ESPT rate in the ZnTNPc system.
  • Ning Meng, Yuji Ando, Sumio Shinoda, Yasukazu Saito
    原稿種別: Article
    専門分野: TP
    1999 年 72 巻 4 号 p. 669-672
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    A unique feature of the dehydrogenation of 2-propanol with Ru–Pt/carbon catalyst in the liquid-film state has been elucidated by means of various kinds of deuterium labeling. A quite large kinetic isotope effect for 2-propanol-d8 (kH/kD = 14.6) suggests that fission of the methine C–H bond in the isopropoxy intermediate is rate-determining in the overall process. The dominant formation of H2 for 2-propanol-O-d1 is explained in terms of rapid scrambling of deuterium together with a large kinetic isotope effect for fission of the methine C–D bond. This picture is supported by both the absence of an appreciable kinetic isotope effect for 2-propanol-O-d1 and the deuterium distribution among the liquid-phase components. The extent of hydrogen transfer from 2-propanol to acetone-d6 during the dehydrogenation reaction suggests suppression of the inhibitive adsorption of acetone, leading to a high catalytic activity in the region of high acetone concentration, which is essential for a 2-propanol/acetone/hydrogen chemical heat-pump system with high thermal efficiency.
  • Takeshi Kubota, Yoshinori Kitajima, Kiyotaka Asakura, Yasuhiro Iwasawa
    原稿種別: Article
    専門分野: TP
    1999 年 72 巻 4 号 p. 673-681
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    We measured Pd L3-edge X-ray absorption near-edge structure (XANES) spectra for small Pd particles dispersed on inorganic oxide supports (SiO2 and Al2O3) and the spectra changes induced by the adsorption and the absorption of hydrogen. When the XANES spectra were measured under the atmosphere of H2, a new peak appeared at about 8 eV above the inflection point of the absorption edge. The peak position was invariant but its intensity decreased with the decrease of Pd particle size. This peak is caused by hydrogen absorption in the Pd particles. Hydrogen at the subsurface region little affected the Pd L3-edge XANES spectra. A new peak also appeared for the Pd sample accompanied with hydrogen adsorbed on the surface. The peak energy relative to the edge was independent of the Pd particle size and the peak intensity increased with the amount of adsorbed hydrogen. The XANES spectra can quantify the adsorbed and absorbed hydrogen atoms. We presented a model of Pd particles composed of surface, subsurface and bulk atoms.
  • Hatsumi Mori, Naoki Sakurai, Shoji Tanaka, Hiroshi Moriyama
    原稿種別: Article
    専門分野: TP
    1999 年 72 巻 4 号 p. 683-689
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    A new series of d-pπ organic conductors ((EDT-TTF)4CoX4(solvent)x [EDT–TTF = ethylenedithiotetrathiafulvalene; X = Cl, Br; solvent = 1,1,2–TCE (trichloroethane), CH2Cl2]) consists of anions including 3d localized spins and donors containing itinerant pπ electrons. The crystal and band structure analyses show that these salts have face-to-face regular donor stacking, the so-called β-type donor arrangement, and that the calculated Fermi surfaces are closed due to relatively large interchain interactions. Resistivity measurements show the metallic behaviors down to 80 K [(EDT-TTF)4CoCl4(1,1,2-TCE)x], 235 K [(EDT-TTF)4CoCl4(CH2Cl2)x], 110 K [(EDT-TTF)4CoBr4(1,1,2-TCE)x], and 190 K [(EDT-TTF)4CoBr4(CH2Cl2)x], respectively. Especially, for (EDT-TTF)4CoCl4(1,1,2-TCE)x, the ESR measurements indicate that the linewidth attributed to EDT-TTF+ increases and that the g-value decreases rapidly when the resistivity starts increasing below 80 K, owing to substantially the dipole–dipole interaction between pπ (EDT-TTF+)-3d (Co2+) spins. At around 33 and 20 K, the anomalies of the ESR linewidth have been observed, suggesting the instability of the pπ part.
  • Kazutoshi Kobayashi, Teruyuki Nagamune, Taiji Furuno, Hiroyuki Sasabe
    原稿種別: Article
    専門分野: TP
    1999 年 72 巻 4 号 p. 691-696
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    A method is provided for forming a monomolecular layer of cytochrome b562 at the air/water interface by introducing dialkyl chains onto a water-soluble cytochrome b562. The purpose of the present study was to form densely and/or regularly packed two-dimensional arrays of protein molecules. Protoheme, which is a prosthetic group of cytochrome b562, was extracted from cytochrome b562, and then dialkylated(dioctadecylated) with the synthetic-chemical procedure. This dioctadecylated heme was reconstituted with apo-cytochrome b562 in dimethyl sulfoxide–water mixtures in vitro. The reconstitution reaction was successful when the reaction time was greater than 50 min, the dimethyl sulfoxide content was 63% and the temperature was maintained at 10 °C. Surface pressure–area per molecule isotherm of the reconstituted dioctadecylated holo-cytochrome b562 was measured and this clearly shows the monolayer formation of the water-soluble protein on the water subphase. The coefficient of compressibility of the protein film was estimated and is discussed. It is found that reconstituted dioctadecylated holo-cytochrome b562 forms a stable and closely packed monomolecular layer on the water surface.
  • Kazunari Yoshizawa, Masamitsu Tachibana, Tokio Yamabe
    原稿種別: Article
    専門分野: TP
    1999 年 72 巻 4 号 p. 697-700
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Alternation of long and short carbon–carbon bonds in large cyclic polyenes are investigated from the point of view of vibrational analyses. [6(2n + 1)]Annulenes, where n is 0, 1, 2,···, are cyclic polyenes that can have planar bond-delocalized D6h or bond-localized D3h structures without severe nonbonded interactions. The B1u and B2u modes of vibration that potentially cause a D6h to D3h transition in benzene, [18]annulene, and [30]annulene are specifically discussed. The delocalized D6h structure is stable in benzene and [18]annulene, but not in [30]annulene. The D6h structure of [30]annulene has an imaginary B2u mode of 416i cm−1 that has relevance to the so-called Kekulé B2u mode of benzene. The D6h structure of [30]annulene is confirmed to be a transition state that leads to the equivalent D3h global minimum in both the forward and reverse directions.
  • Tomohiro Narukawa, Wataru Yoshimura, Atsushi Uzawa
    原稿種別: Article
    専門分野: AI
    1999 年 72 巻 4 号 p. 701-706
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    A separation method, using solvent extraction and cobalt(III) oxide collection, has been studied for determining the total arsenic in environmental and geological samples by electrothermal atomic absorption spectrometry (ETAAS) using a tungsten furnace. After arsenic iodide was extracted into benzene, cobalt(III) oxide powder was added to the benzene solution to collect the extracted arsenic. The cobalt(III) oxide was separated from benzene by vacuum filtration and then suspended in 5 cm3 of water. The slurry was introduced into the tungsten furnace and the determination of arsenic was performed. The relative standard deviation of the proposed method at the 0.20 mg dm−3 arsenic level was 2.4% (n = 10). The calibration curve obtained with the proposed method was linear up to 0.50 mg dm−3 (5.00 ng/10 mm3), and the detection limit (3σ) was 12 μg dm−3 (0.12 ng/10 mm3). The present method was applied to the analysis of some environmental and geological standard reference materials, and the concentrations of total arsenic obtained by the present method were in good agreement with the certified values or the reference values of those samples.
  • Mi Hee Lim, Yoon Jung Lee, Yeong Mee Goh, Wonwoo Nam, Cheal Kim
    原稿種別: Article
    専門分野: AI
    1999 年 72 巻 4 号 p. 707-713
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    The catalytic hydroxylation of aliphatic hydrocarbons by m-chloroperbenzoic acid (MCPBA) has been studied in the presence of elecrtron-deficient iron(III) porphyrin complexes. High yields of alcohol products were obtained with small amounts of ketone formation under mild reaction conditions. The stereospecificity and regioselectivity of the iron porphyrin complexes have been investigated in hydroxylation reactions as well. The hydroxylation of alkanes has been performed in the presence of isotopically 18O-labeled water, H218O, in order to understand the effects of the electronic nature of iron porphyrin complexes, the concentration of H218O, the C–H bond strength of alkanes, and the reaction temperature on the 18O-incorporation from the labeled water into alcohols. We found that the amounts of 18O incorporated into the alcohol products varied in the reactions; these results were interpreted with that the reaction of oxygen atom transfer from a high-valent iron oxoporphyrin complex to alkanes competes with that of oxygen atom exchange between the intermediate and labeled water that leads to 18O-incorporation from H218O into the alcohol products. Deuterium kinetic isotope effects (KIEs) in the alkane hydroxylations by the iron porphyrin complexes and MCPBA have been studied with a mixture of cyclohexane and cyclohexane-d12. The KIE values obtained in the reactions were found to depend significantly on the nature to the iron porphyrin complexes. The temperature dependence of kH/kD was also studied from −40 to 25 °C and the parameters of Arrhenius equation (i.e., the pre-exponential factor ratio, AH/AD, and the isotopic difference of C–H and C–D bond activation energies, Ea(D)–Ea(H)) were determined.
  • Masanobu Watanabe, Masaru Sato, Akira Nagasawa, Masahiro Kai, Izumi Mo ...
    原稿種別: Article
    専門分野: AI
    1999 年 72 巻 4 号 p. 715-723
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    An interesting dimerization occurred during the oxidation of ruthenocene with an excess of p-benzoquinone containing BF3·Et2O (abbreviated p-Bq/BF3) in a mixed solution of benzene and hexane, which gave biruthenocenium(BF4)2 (A) in 89% yield. Reduction of A with TiCl3 gave biruthenocene in a good yield (68% from ruthenocene), which is the most elegant preparation of biruthenocene. Recrystallization of A from CH3NO2 containing C2H5CN gave a mixed-valence salt 3 formulated as [RuIICp(C5H4C5H4)CpRuIVC2H5CN](BF4)(B2F7)CH3NO2 in which C2H5CN coordinated to the RuIV center. The crystal of 3 was found to be monoclinic, space group P21/a, a = 9.8930(8), b = 15.445(3), c = 19.728(3)Å, β = 92.57(1)°, V = 3011.3(1) Å3, Z = 4, and the final R = 0.075and Rw = 0.093. Recrystallization of A from CH3NO2 containing 2,2′-bipyridine and p-benzoquinone gave a yellow planar salt 4 formulated as [RuIICp(2,2′-bipyridine)(p-benzoquinone)]BF4 in which the olefin moiety of p-benzoquinone coordinated to the RuIV center in η2-form. Salt 4 was also synthesized by the reaction of bromoruthenocenium (BF4) with p-benzoquinone and 2,2′-bipyridine in CH3NO2. The crystal of 4 was found to be monoclinic, space group P21, a = 8.516(3), b = 9.934(4), c = 11.995(4) Å, β = 103.78(1)°, V = 985.6(6) Å3, Z = 2, and the final R = 0.040 and Rw = 0.050. The same p-Bq/BF3 oxidation of osmocene gave an orange red salt 5 formulated as [Cp2OsIVFBF3]BF4 in which one of the F atom of the BF4 ion coordinated to the OsIV center. The crystal of 5 was found to be monoclinic, space group P21/c, a = 8.065(1), b = 12.048(1), c = 16.730(2) Å, β = 94.497(8)°, V = 1620.6(3) Å3, Z = 4, and the final R = 0.055 and Rw = 0.070.
  • Nobuko Komatsuzaki, Yuichiro Himeda, Takuji Hirose, Hideki Sugihara, K ...
    原稿種別: Article
    専門分野: AI
    1999 年 72 巻 4 号 p. 725-731
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Three dinuclear colmplexes, two Ru(II)–Co(III) and one Ru(II)–Ni(II) polypyridyl complexes, were prepared by the use of ethylene- and pentamethylene-linked bisphenanthroline as the bridging ligands. Their photochemical and electrochemical properties were examined. Each metal complex component was shown to be electronically insulated. Since the roles of the Ru(II) as a photosensitizer and the Co(III) or Ni(II) moiety as an electron acceptor were expected, a photocatalytic CO2 reduction experiment was carried out. The catalytic ability of the Ru(II)–Co(III) system was shown to be almost the same as the corresponding intermolecular systems with the improved CO/H2 selectivity, showing that the Co(III) polypyridyl complex was as effecticve as the Co(II) species for a catalytic center.
  • Makoto Tamaki, Mikihiro Yabu, Tomomi Saeki, Ayako Kaneko, Sadatoshi Ak ...
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 733-739
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    The solvent-dependent conformations of cyclo(–δ-Ava–L-Pro–)2 were characterized by means of the 1H and 13H NMR, CD, and IR spectra. CD results in CH2Cl2, CH3CN, CH3OH, and H2O indicated that the change in polarity of the solvent induces a reversible change in the conformation of cyclo(–δ-Ava–L-Pro–)2, revealed by the decrease of the negative peak near to 230 nm and then by the gradual appearance of a negative trough near to 210 nm. The NMR data in CD3Cl, CD2Cl2, CD3CN, and CD3OH confirmed that cyclo(–δ-Ava–L-Pro–)2 has a C2 symmetric conformation consisting of all-trans peptide-bond backbones in all solvents, and that the change in polarity of the solvent induces a difference in the rotational states of the Pro αC–C=O single bond.
  • Tohru Nakashima, Ryoji Fujiyama, Mizue Fujio, Yuho Tsuno
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 741-750
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    The solvolysis rates of 2,2-dimethyl-3-(trimethylsilyl)propyl and 3-(aryldimethylsilyl)-2,2-dimethylpropyl p-toluenesulfonates were measured in a wide variety of solvents at 45 °C. The solvent effects were analyzed by using the Winstein–Grunwald equation. The solvent effects observed did not give simple linear correlations with the 2-adamantyl YOTs parameter, but showed dispersion behavior in a series of binary solvents. The m values of 0.59—0.67 were remarkably lower than unity for the limiting kc solvolysis of 2-adamantyl p-toluenesulfonate. The deviation patterns could not be interpreted in terms of nucleophilic assistance by the solvent. The dispersion behavior with reduced m values was found to be more significant for the 3-(aryldimethylsilyl) than for the 3-(trimethylsilyl) derivatives and was compatible with the delocalization of the incipient cationic charge by participation of the Si–Cγ bond in the rate-determining step. An extended dual-parameter treatment, log (k/k80E) = mcYOTs + mΔYΔ, successfully correlated such γ-silyl assisted solvolyses. The MΔ values of 0.24—0.49 so obtained, where MΔ = 0.51mΔ/(mc + 0.51mΔ), are a measure of the extent of charge delocalization, suggesting that the γ-silyl group in the percaudal interaction is more effective in delocalizing the cationic charge than the alkyl group in C–C σ-participation, but less so than π-assisted interaction by the β-aryl group.
  • Shakila Rahman, Narihiko Fukamiya, Harukuni Tokuda, Hoyoku Nishino, Ki ...
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 751-756
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Three new quassinoid derivatives [desmethyl-brusatol (1), desmethyl- bruceantinoside A (2), and butyl ester (3) of bruceoside D (6)] were isolated from the extract of Brucea javanica. Their structures were elucidated by spectral evidence and chemical transformation to or from known compounds. The three new quassinoid derivatives and related compounds have shown inhibitory effects against TPA-induced Epstein–Barr virus early antigen (EBV-EA) activation.
  • Tadamitsu Sakurai, Kazue Miyata (nee Nojima), Kenichiro Watanabe, Kanj ...
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 757-764
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    1-(Bromoacetyl)pyrene (BAP) was found to selectively alkylate the cysteine-25 residue (Cys-25) of papain, inactivating the enzyme. A comparison of the spectroscopic behavior of BAP-modified papain with that of the reference compound, 1-{[2-(acetylamino)ethylthio]acetyl}pyrene (TAP), showed that the pyrenecarbonylmethyl pendant (covalently bound to Cys-25 in a 1 : 1 stoichiometric ratio) gives a new absorption around 390 nm and a long-wavelength fluorescence at 465 nm, which are both characteristic of an associated dimer. Effects of solvent and concentration on the absorption and emission spectra of TAP as well as the derivatized enzyme substantiate the dimer formation in the ground state. The finding that the pendant-carbonyl-13C carbon signal undergoes a large upfield shift in the papain active site, as compared to the corresponding signal of 13C-labeled TAP, confirms that the pyrenecarbonyl moiety adopts an enolate-type resonance structure (making the pyrene ring electron-deficient) on formation of a strong hydrogen bond to the neighboring amino acid residue(s). It is proposed that the significant contribution of the enolate-type resonance structure is a driving force for promoting the dimerization of the pyrenecarbonylmethyl reporter group attached to Cys-25 mainly through dipole–dipole and hydrophobic interactions. On the other hand, the introduction of the imino spacer between the 1-pyrenyl carbon and the acetyl carbonyl carbon in BAP-derived pendant greatly weakened a tendency to produce a pendant dimer in the ground state, providing a piece of evidence in support of this proposal.
  • Shinkiti Koto, Kazuyasu Asami, Motoko Hirooka, Kazuo Nagura, Mizue Tak ...
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 765-777
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    This report describes a simple synthesis of 2-azido-3,4,6-tri-O-benzyl-2-deoxy-D-glucopyranose. Glycosylation using this as well as 2-azido-3,4,6-tri-O-benzyl-2-deoxy-D-galactopyranose and -mannopyranose was achieved with the aid of a reagent system consisting of p-nitrobenzenesulfonyl chloride, silver trifluoromethanesulfonate, and triethylamine, and its modifications. O-(2-Acetamido-2-deoxy-β-D-glucopyranosyl)-(1→4)-O-α-D-mannopyranosyl-(1→4)-α-D-mannopyranose, the repeating unit of the main chain of the O-specific cell wall polysaccharide of E. coli 058 was synthesized.
  • Masanori Wada, Katsuhiko Kirishima, Yuichi Oki, Masafumi Miyamoto, Mas ...
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 779-785
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    In the presence of a catalytic amount of acid, the title xanthenol (1) reacted in acetone to give 1,8-dimethoxy-9-phenylxanthen-9-ylmethyl methyl ketone. Analogous reactions were observed for ethyl methyl ketone and acetophenone, but not for diethyl ketone. Propanal and butanal also reacted to give 2-(1,8-dimethoxy-9-phenylxanthen-9-yl)propanal and 2-(1,8-dimethoxy-9-phenylxanthen-9-yl)butanal, respectively. In hot primary and secondary alcohols, 1 was reduced to give 1,8-dimethoxy-9-phenylxanthene. 1 also reacted with methoxybenzenes, phenol, and N-alkylanilines to give 9-aryl-1,8-dimethoxy-9-phenylxanthenes. The basicity of 1, or the stability of the carbenium ion (pKR+ = −0.81), was measured in hydrochloric acid and compared with those of related 9-arylxanthen-9-ols, such as 1,8-dimethoxy-9-(2,6-dimethoxyphenyl)xanthen-9-ol (1.14), 9-(2,6-dimethoxyphenyl)xanthen-9-ol (4.80) (8), and 9-phenylxanthen-9-ol (0.75). The drastic differences in the reactivities and the basicity between 1 and 8 were attributed to a steric effect rather than an electronic effect.
  • Hajime Abe, Hitomi Suzuki
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 787-798
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Some copper(I) and (II) compounds have been found to act as efficient reagents for the nucleophilic displacement of 1-haloalkynes. Copper(I) iodide smoothly transforms 1-bromoalkynes (2) into 1-iodoalkynes (1) which, on further treatment with copper(II) bis(arenesulfinate), are readily converted to the corresponding alkynyl aryl sulfones (4). The kinetic data of the halogen exchange between (4-chlorophenyl)ethynyl bromide (2d) and CuI have shown that the reaction is linearly dependent on the concentrations of both compounds. A mechanistic pathway involving the single electron transfer between 1-haloalkynes and copper(I) salt has been proposed for the present copper-assisted halogen exchange reaction at acetylenic carbon atom.
  • Kazuhiro Nagayama, Isao Shimizu, Akio Yamamoto
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 799-803
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    The aryl trifluoroacetates oxidatively added to a zerovalent palladium complex 2a with acyl-O bond cleavage under mild conditions to give the corresponding trans-(aryloxo)(trifluoroacetyl)palladium complexes 3a3c. But 4-nitrophenyl trifluoroacetate reacted with 2a to yield cis-[Pd(OC6H4-4-NO2)2(PMe3)2] 3d, which was produced with C–O bond activation followed by disproportionation reaction. In contrast, benzyl trifluoroacetates reacted with the Pd(0) complex with benzyl–O bond fission to form benzyl(trifluoroacetato)palladium complexes 4a4d. Complexes 4a4d are in equilibrium in solutions between trans and cis isomers, with the proportion of the cis isomer increasing in polar solvents. Palladium-catalyzed carbonylation of benzyl trifluoroacetate has been achieved in the presence of benzyl alcohol and triethylamine to yield benzyl phenylacetate.
  • Satoru Furuta, Manabu Kuroboshi, Tamejiro Hiyama
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 805-819
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Trifluoromethyl-substituted aromatic compounds were easily synthesized by the oxidative desulfurization-fluorination reaction of readily accessible methyl arenecarbodithioates using [n-Bu4N]H2F3 and 1,3-dibromo-5,5-dimethylhydantoin (DBH) under extremely mild conditions. Use of N-bromosuccinimide or N-iodosuccinimide instead of DBH afforded difluoro(methylthio)methyl-substituted aromatics. In a similar way, 3,3,3-trifluoropropenyl-substituted aromatic compounds were readily prepared from the corresponding α,β-unsaturated carbodithioates.
  • Takashi Hoshi, Hiroyuki Yasuda, Takanobu Sanji, Hideki Sakurai
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 821-827
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Ruthenium-catalyzed ring-closing metathesis (RCM) reactions of various α,ω-bis(allyldimethylsilyl)-, bis(dimethylvinylsilyl)-, and bis(dimethylvinyloxysilyl)-substituted compounds are examined. The steric and electronic influences of the substrates on the RCM reaction were discussed. Although the successful ring-closing reactions are limited to seven- and eight-membered rings, disilacycloalkene derivatives constructed with –SiMe2–CH2–SiMe2–, –SiMe2–(CH2)2–SiMe2–, –SiMe2–O–SiMe2–, –SiMe2–N(Ph)–SiMe2–, and a vinylene unit in the ring system were obtained in good to reasonable yields under the mild reaction conditions. The limitation of the reactions is mainly ascribed to Si–C and Si–Si bonds being longer than the C–C bond in the ring system.
  • Masaaki Ueki, Takayoshi Ikeo, Kumiko Hokari, Keiko Nakamura, Akihiko S ...
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 829-838
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    An efficient methylene insertion reaction to construct an S–CH2–S bridge between two cysteine residues occurred when the thiol-protecting dimethylphosphinothioyl (Mpt) group of Z–Cys(Mpt)–OMe was removed with tetrabutylammonium fluoride hydrate in CH2Cl2. The thiol-free form gave similar results, albeit the yields were somewhat lower. In both cases, the best yields were obtained using 2 molar amounts of the reagent. Higher amounts of the reagent reduced the yield because of dehydroalanine formation. In the case of penicillamine, the thiol-free form was better in reactivity than the S-Mpt form, which required double the amount of the reagent to give the same yield. The reaction was successfully used in a synthesis of a cyclic enkephalin analog with the S–CH2–S bridge.
  • Shunji Ito, Shigeru Kikuchi, Noboru Morita, Toyonobu Asao
    原稿種別: Article
    専門分野: OB
    1999 年 72 巻 4 号 p. 839-849
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Extremely stable carbocations, tris(6-methoxy-1-azulenyl)methyl (8), bis(6-methoxy-1-azulenyl)(4-methoxyphenyl)methyl (9a), and (6-methoxy-1-azulenyl)bis(4-methoxyphenyl)methyl (10a) cations and a series of di(1-azulenyl)phenylmethyl and (1-azulenyl)diphenylmethyl cations having methoxy substituents on each phenyl group, i.e., di(1-azulenyl)(4-methoxyphenyl)methyl (9b) and (1-azulenyl)bis(4-methoxyphenyl)methyl (10b) cations and 3-methyl-1-azulenyl (9cand 10c) and 3,6-di-t-butyl-1-azulenyl (9d and 10d) analogues, were synthesized by hydride abstraction from the corresponding methane derivatives and their properties were fully characterized. The pKR+ values of 8 and 9a were well beyond 14.0. The value of 10a was determined as 13.2, which is higher by 10.2 pK units than that of (1-azulenyl)diphenylmethyl cation. The value also considerably increased by the methoxy substitution on each phenyl group. The values of 9bd (pKR+ 11.7—13.4) and 10bd (pKR+ 5.2—7.0) are higher by 1.0—1.4 and 2.2—2.4 pK units than those of the corresponding analogous benzyl and diphenylmethyl cations. The electrochemical reduction of 8, 9ad, and 10ad showed a wave at −0.88, −0.71 — −0.83, and −0.56 — −0.71 V (V vs. Ag/Ag+), respectively, upon cyclic voltammetry (CV). The relatively high reduction potentials also exhibited the stabilization of the methyl cations by the methoxy substituents. The oxidation of 8 in acetonitrile exhibited barely separated two-step, one-electron oxidation waves at a potential range of +0.90 — +0.98 V upon CV, although 9ad and 10ad did not show two similar waves at a narrow potential range. The wave is ascribed to the oxidation of two azulene rings to generate a trication species.
  • Norimitsu Tohnai, Yoshiaki Inaki, Mikiji Miyata, Nobuyoshi Yasui, Eiko ...
    原稿種別: Article
    専門分野: AM
    1999 年 72 巻 4 号 p. 851-858
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Two kinds of crystal structures were found for 1-octylthymine from X-ray structure analysis: Structure I was obtained from Crystal I recrystallized from ethyl acetate, and Structure II was obtained from Crystal II recrystallized from ethanol. The thymine bases in Crystal I had high reactivity for photodimerization. Crystal II, however, was inactive for the photodimerization of thymine bases. This paper presents the crystal structure of 1-octylthymine crystallized from ethanol (Crystal II) by X-ray crystal structure analysis. Thymines in Crystal II were concluded to be inactive for photodimerization because of unsuitable orientation of thymine bases in the crystal and because of insufficient space for rotation of thymine during photodimerization.
  • Abhijit Sarkar, Satya S. Talwar
    原稿種別: Article
    専門分野: AM
    1999 年 72 巻 4 号 p. 859-864
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Diynes with heteroaromatic sidegroups directly linked to the acetylenic backbone were found to show liquid crystalline behaviour upon heating. Thus, 1,4-di(2-thienyl)-1,3-butadiyne, 1,4-di(3-thienyl)-1,3-butadiyne, 1,4-di(3-benzo[b]thienyl)-1,3-butadiyne, 1-(3-quinolyl)-4-(2-thienyl)-1,3-butadiyne, 1-(3-quinolyl)-4-(3-thienyl)-1,3-butadiyne, and 5-(2-thienyl)-2,4-pentadiyne-1-ol were investigated for their thermal behavior. These diynes also underwent polymerization in their liquid crystalline state, although the polymers so formed did not show liquid crystalline behavior. It was found that the S-atom of the heteroaromatic moieties tends to play a role in making the diynes show liquid crystalline behavior. Differential scanning calorimetry, thermogravimetric analysis and hot stage microscopy were used to investigate the liquid crystalline nature of the diynes. All of them showed a nematic liquid crystalline phase upon annealing, whereas smectic phase was totally absent.
  • Takuji Hirose, Zhen-He Wang, Bruce W. Baldwin, Tadafumi Uchimaru, Kazu ...
    原稿種別: Article
    専門分野: AM
    1999 年 72 巻 4 号 p. 865-873
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    Transport abilities of alkaline earth, transition, and heavy metal ions were examined for three kinds of disubstituted monoacid derivatives of Kemp’s triacid as transport agents for a liquid membrane system. Diamide derivatives showed high transport ability for CaII over MgII, with selectivity ratios greater than 25. Imide monoacids were also CaII selective. For transition and heavy metal ions, all monoacids including diester monoacid showed very high HgII transport, but with different selectivities depending on the functional group. High HgII/AgI ( = 24), HgII/CuII ( = 194), and HgII/PbII ( = 85) selectivities were observed for diamide, diester, and imide monoacids, respectively. The transport mechanisms are discussed for alkaline earth, transition, and heavy metal ions utilizing ion chromatography analysis of anions co-transported.
  • Yuichiro Haramoto, Yoshiharu Akiyama, Ryouichi Segawa, Masato Nanasawa ...
    原稿種別: Article
    専門分野: AM
    1999 年 72 巻 4 号 p. 875-878
    発行日: 1999年
    公開日: 2003/12/24
    ジャーナル 認証あり
    New pyridinium type thermotropic ionic liquid crystal materials bearing a 1,3-oxathiane ring in their central core: N-substituted 4-(5-alkyl-1,3-oxathian-2-yl)pyridinium bromides (8) and corresponding 1,3-dioxane analogs (10) were synthesized. And the mesomorphic behaviors of these two systems are compared. The principal feature of these compounds is to exhibit a smectic A phase over a very wide temperature range including room temperature [for example 8-4: G −7 SmA 166 I; 10-4: G −24 SmA 152 I (°C)].
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