Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 76 , Issue 8
Showing 1-26 articles out of 26 articles from the selected issue
  • Hitoshi Watarai, Satoshi Tsukahara, Hirohisa Nagatani, Akira Ohashi
    Type: Accounts
    Subject area: AI
    2003 Volume 76 Issue 8 Pages 1471-1492
    Published: 2003
    Released: August 15, 2003
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    Recent development of the interfacial nanochemistry in the solvent extraction systems is reviewed, as well as the development of measurement methods for interfacial reactions. The studies on specific reactions at the interface of various metal extraction systems have elucidated essential modes of the interfacial reactions, including the interfacial adsorption, the interfacial complexation, and the interfacial aggregation. The catalytic role of the liquid-liquid interface in the solvent extraction kinetics and the molecular recognition ability of the self-assembled metal complexes at the interface were emphasized. Spectroscopic studies on the rotational and translational dynamics of fluorescent molecules, a single molecule in some cases, at the interface are also discussed. The utility of the molecular dynamics simulations is demonstrated in the discussions of the solvent structure in the interfacial region and of the stability of surface active molecules at the interface.
  • Yasuhiko Suzuki, Hiroshi Terao, Terunori Fujita
    Type: Accounts
    Subject area: OB
    2003 Volume 76 Issue 8 Pages 1493-1517
    Published: 2003
    Released: August 15, 2003
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    Olefiin polymerization behavior of phenoxy-based catalysts has been discussed. Phenoxy-based olefin polymerization catalysts are capable of showing high catalytic activities. Moreover, the phenoxy-based catalysts can display unique catalytic properties and thus have offered opportunities to make polyolefinic materials that are difficult or impossible to prepare using conventional catalysts. Therefore, the phenoxy-based catalysts have opened up a new dimension in the fields of olefin polymerization catalysis and polymer synthesis.
  • Makoto Wakeshima, Kentaro Ino, Yukio Hinatsu, Yoshinobu Ishii
    Type: Headline
    Subject area: AI
    2003 Volume 76 Issue 8 Pages 1519-1525
    Published: 2003
    Released: August 15, 2003
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    Magnetic properties of quaternary iron sulfides, BaLn2FeS5 (Ln = Ce, Pr, Nd, Sm), have been investigated through magnetic susceptibility, electrical resistivity, specific heat, 57Fe Mössbauer spectrum, and powder neutron diffraction measurements. In these compounds, the Fe2+ ion exhibits an antiferromagnetic ordering at around 40 K. In the Nd and Sm compounds, these lanthanide ions show an antiferromagnetic ordering at 6.5 K for Ln = Nd and at 28 K for Ln = Sm. The reduction of the Fe2+ magnetic moment is observed below 120–170 K for all the compounds. Their electrical conductivities show an Arrhenius temperature-dependence, and the activation energies change at around the moment-reduction temperatures. The 57Fe Mössbauer spectra for BaPr2FeS5 indicate that the FeS4 tetrahedron is distorted prominently below the temperature at which both the magnetic susceptibility and the electrical resistivity show an anomaly in their temperature dependence. The neutron diffraction data collected for BaPr2FeS5 at 10 K show that it has a collinear antiferromagnetic structure and that the magnetic moments of the Fe2+ ions are parallel to the c-axis.
  • Abd El-Rahman El-Sayed, Ali Mohamed Shaker, Hatem Gad El-Kareem
    Type: Article
    Subject area: TP
    2003 Volume 76 Issue 8 Pages 1527-1535
    Published: 2003
    Released: August 15, 2003
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    The electrochemical and corrosive behaviour of antimony and antimony-tin alloys (Alloy No./Sb(wt. %); I/90, II/80, III/65, IV/50) as anodes in various aqueous concentrations of KOH have been investigated using galvanostatic, potentiodynamic and potentiostatic techniques. Galvanostatic potential–time curves at 4 mA cm−2 revealed that passivation of both antimony and antimony tin alloys is inhibited by an increase in KOH concentration. The opposite effect was observed with an increase in Sn content in the alloy. At high Sn content and low [OH] a pseudo passivation potential was observed. (Abnormal early passivation occurring in the active anodic region due to the formation of tin oxides, which dissolve in alkali. Then, potential decreases.) The alloy with 50% Sn exhibited immediate passivation. The potentiodynamic curves were swept from Eo.c up to +1000 mV vs SCE. The results showed an increase in the peak current (Ip) for antimony and its alloys with increasing [OH] on the oxide film. The first three alloys showed two anodic peaks at −780 and −450 mV, but the forth traced a third peak at −940 mV. X-ray diffraction and SEM micrographs detailed the electrochemical results and morphology of the electrode surface.
  • Somsak Tonmunphean, Atchara Wijitkosoom, Yuthana Tantirungrotechai, Na ...
    Type: Article
    Subject area: TP
    2003 Volume 76 Issue 8 Pages 1537-1541
    Published: 2003
    Released: August 15, 2003
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    The magnetizabilities of three ring-structured molecules, [8]-cyclacene, [8]-BN-cyclacene, and [8]-collarene, were subsequently calculated at the B3LYP/6-31G* level with the CSGT gauge-origin treatment. The magnetizability of [8]-cyclacene shows a large diamagnetic nature in the direction parallel to the ring cylindrical axis, while the value of [8]-BN-cyclacene is nearly isotropic, and that of [8]-collarene is slightly more diamagnetic in the perpendicular direction than in the parallel direction. A large diamagnetic magnetizability in the parallel direction of [8]-cyclacene arises from the current flow around the ring circumference. The magnetic environment in the ring channel of these three molecules was investigated by calculating the nuclear shielding tensor of the 3He atom when the atom moves through the ring channel. The GIAO nuclear shielding tensor changes significantly toward a prolate shape in [8]-cyclacene, but becomes a slightly oblate shape in [8]-BN-cyclacene and [8]-collarene. The changes correlate well with the magnetizabilities of the ring-structured molecules.
  • Magda Ali Akl, Mohammed Abdel Ghany Kabil, Amin Mahmoud Abdallah, Dali ...
    Type: Article
    Subject area: AI
    2003 Volume 76 Issue 8 Pages 1543-1547
    Published: 2003
    Released: August 15, 2003
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    The extraction and preconcentration of a metal complex via surfactant-mediated phase separation was studied. A sensitive, selective and low-cost methodology for the determination of microamounts of Lanthanum and Yttrium, using alizarin red sulfonate (ARS) with a flotation step prior to absorptiometric determination was developed. The precipitate in the scum layer was quantitatively collected, stripped with 10% HNO3 and measured by spectrophotometry at 650 nm. Stripping of La(III) and Y(III) from the scum layer was carried out in one step with different mineral acids. The stripping efficiency was found to be quantitative in the case of HNO3. Excess ARS was used to nullify the interfering effects of various foreign species. The proposed procedure has been applied to the determination of La and Y spiked in natural water samples and real ore samples. Additionally, the mechanism of flotation of the metal chelate was proposed to be due to a physical interaction between the metal chelate and the oleic acid surfactant through the van der Waal force.
  • Yuko Takao, Tokuji Takeda, Jun-ichiro Setsune
    Type: Article
    Subject area: AI
    2003 Volume 76 Issue 8 Pages 1549-1553
    Published: 2003
    Released: August 15, 2003
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    Pyridine and ethylenediamine reacted with Pd(II) complexes of N21,N22-bridged porphyrins to give mixed-ligand Pd(II) complexes. The UV-vis and 1H NMR spectral features of the porphyrin ligand provide information regarding the nature of the coexisting ligands and Pd(II) coordination geometry in the products. That is, the splitting pattern in the Soret region of the UV-vis spectra was dependent on whether porphyrinatopalladium(II) was coordinated by neutral ligands or anionic ligands. In the 1H NMR spectra of ethylenediamine complexes of porphyrinatopalladium(II), signal broadening of porphyrin β-pyrrole protons and a chemical shift change of ethylenediamine protons were seen in the dichloride in comparison with the bis(perchlorate). These phenomena indicate the equilibrium of the coordination and dissociation of chloride and amine at the apical and basal sites in the square pyramid. The H–D exchange in the ethylenediamine ligand was promoted by the presence of chloride.
  • Koji Oshita, Jingsong Xu, Yun-Hua Gao, Kyue-Hyung Lee, Mitsuko Oshima, ...
    Type: Article
    Subject area: AI
    2003 Volume 76 Issue 8 Pages 1555-1560
    Published: 2003
    Released: August 15, 2003
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    A chitosan resin possessing the leucine moiety (leucine-type chitosan) was newly synthesized by using the chitosan cross-linked with ethylene glycol diglycidyl ether (EGDE) as a basic material. The adsorption behavior of trace amounts of metal ions on the leucine-type chitosan was systematically examined by packing it in a mini-column by ICP-MS (inductively coupled plasma mass spectrometry). Molybdenum was adsorbed on the resin quantitatively and was easily eluted with 1 M nitric acid. The optimized pH range was from 1 to 5, and Mo was collected by the chelation mechanism and/or the anion-exchange mechanism. The method was applied to the determination of Mo in sea and river water samples. A pretreatment with the resin could remove the matrix components in seawater. Preconcentration by 100-fold was accomplished by a column treatment, which had a sufficient concentration to measure trace Mo in river water samples by ICP-AES (inductively coupled plasma atomic emission spectrometry) and GFAAS (graphite furnace atomic absorption spectrometry): LODs with a 100-fold preconcentration by ICP-AES and GFAAS were 0.007 ng mL−1 and 0.009 ng mL−1, respectively, and the RSDs were both within 4.0%.
  • Reiko Azumi, Midori Goto, Kazumasa Honda, Mutsuyoshi Matsumoto
    Type: Article
    Subject area: AI
    2003 Volume 76 Issue 8 Pages 1561-1567
    Published: 2003
    Released: August 15, 2003
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    X-ray single crystal analyses revealed the molecular geometry and molecular packing of odd-numbered α-oligothiophenes (septithiophene, quinquethiophene and terthiophene) in single crystals prepared by sublimation. Septithiophene crystallizes into triclinic, which is in contrast to the monoclinic packing of even-numbered oligomers. The molecular arrangement of septithiophene in a single crystal resembles that reported for even-numbered oligomers, while the molecules take a more random conformation: only one of the two terminal thienyl rings exhibits disorder and significant torsion from the conjugated plane. The X-ray diffraction data of a quinquethiophene single crystal suggest that the molecule with one of the two different orientations randomly occupies each site.
  • Takahira Tokimoto, Satoshi Tsukahara, Hitoshi Watarai
    Type: Article
    Subject area: AI
    2003 Volume 76 Issue 8 Pages 1569-1576
    Published: 2003
    Released: August 15, 2003
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    The kinetics of the fast complexation of zinc(II) with 8-quinolinol (Hqn) and 5-octyloxymethyl-8-quinolinol (Hocqn) at the 1-butanol/water interface was investigated with two-phase sheath flow/laser-induced fluorescence microscopy. The micrometer-sized two-phase sheath flow system was constructed in a flow cell, in which the 1-butanol phase was introduced as an inner flow and the aqueous phase as an outer flow. The fluorescence emitted from the zinc(II) complex was corrected by an objective lens, and detected with a CCD camera. It was revealed that the fluorescence intensity had a maximum value at the interfacial region, and increased with the reaction time up to 2 ms after the formation of the interface. The complexation rate increased with the increase of the initial ligand concentration in the organic phase, giving a saturation curve. The complexation rate of Hqn with zinc(II) was three times faster than that of Hocqn at equivalent conditions. A digital simulation taking into account the interfacial formation rate of 1:1 complex, the interfacial adsorption of the ligand and complex, and the diffusion of each species reproduced accurately the observed results. It was suggested that the interfacial adsorption of ligands was delayed and depressed by the preferential occupancy of 1-butanol molecules at the interface.
  • Kazuto Nagata, Nobuhiro Takeda, Norihiro Tokitoh
    Type: Article
    Subject area: AI
    2003 Volume 76 Issue 8 Pages 1577-1587
    Published: 2003
    Released: August 15, 2003
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    The first platinum disulfur and diselenium complexes, [Pt(S2)(ArMe2P)2] (Ar = Tbt (4a), Bbt (4b)) and [Pt(Se2)(ArMe2P)2] (Ar = Tbt (5a), Bbt (5b)), have been synthesized by the reactions of the corresponding overcrowded platinum(0) complexes [Pt(ArMe2P)2] with elemental sulfur and selenium. Molecular structures of 4b and 5b were established by X-ray crystallographic analyses, which show a novel three-membered PtE2 (E = S, Se) ring structure with a square planar geometry around the platinum center. The oxidation of 4b and 5b with an equimolar amount of m-chloroperbenzoic acid or tert-butyl hydroperoxide in dichloromethane afforded the corresponding disulfur and diselenium monoxide complexes [Pt(E2O)(BbtMe2P)2] (E = S (6), Se (7)), respectively. An interesting difference in reactivity between 6 and 7 was shown in the further reactions with an excess of oxidants, which produced the corresponding O,S-coordinated thiosulfate complex [Pt(S2O3)(BbtMe2P)2] (8) and the O,O-coordinated selenite complex [Pt(SeO3)(BbtMe2P)2] (11), respectively. The dynamic behavior in solution was revealed by the variable-temperature NMR spectroscopy for 4b, 5b, 8, and 11, which indicates the existence of the intramolecular CH···E (E = O, S, Se) interactions between the methine hydrogens of the o-bis(trimethylsilyl)methyl groups and the Pt-bonded heteroatoms.
  • Kohta Matsumoto, Keisuke Arimura, Masaaki Ohba, Hisashi Okawa
    Type: Article
    Subject area: AI
    2003 Volume 76 Issue 8 Pages 1589-1594
    Published: 2003
    Released: August 15, 2003
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    The reaction of N,N′-dimethyl-N,N′-trimethylenedi(3-aminomethyl-5-methylsalicylaldehydato)copper(II) with 1,3-diaminopropane in DMF afforded the [1+1] condensation product [Cu(L)] and the [2+2] condensation product [Cu2(R)]. The dinucleating macrocyclic ligand (L)2− has one N(amine)2O2 and one N(imine)2O2 metal-binding sites sharing two phenolic oxygen atoms and the tetranucleating macrocyclic ligand (R)4− has two N(amine)2O2 and two N(imine)2O2 sites in an alternate arrangement in the macrocyclic framework. The mixture of [Cu(L)] and [Cu2(R)] was treated with CuCl2 to give [Cu2(L)Cl2] (1a) and [Cu4(R)Cl4] (2a), which were separated based on different solubility in methanol. 1a and 2a were converted into [Cu2(L)](ClO4)2 (1b) and [Cu4(R)(dmf)2](ClO4)4·2H2O (2b), respectively, by the treatment with AgClO4. 1a and 1b each has a dinuclear core doubly bridged by the phenolic oxygen atoms. The crystal structure of [Cu4(R)(dmf)2](ClO4)4·2DMF·H2O·PrOH (PrOH = 2-propanol) (2b′) was determined by X-ray crystallography. It has a dimer-of-dimers structure where each N(amine)2O2 entity accommodates one Cu ion in the usual tetradentate chelating mode, whereas each N(imine)2O2 entity assumes a spread shape to combine one Cu ion with its NO donor atoms and another Cu ion with the remaining NO donor atoms. 2b can be converted into 2a in the presence of chloride ion. Based on magnetic and visible spectral studies, 2a is supposed to have a folded structure of 2b with two Cu–Cl–Cu linkages.
  • Yoshitaka Takagai, Shukuro Igarashi
    Type: Article
    Subject area: AI
    2003 Volume 76 Issue 8 Pages 1595-1600
    Published: 2003
    Released: August 15, 2003
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    Cyanocobalamin (vitamin B12) was selectively extracted from a biological sample by the homogeneous liquid–liquid extraction based on a pH-dependent phase separation with perfluorooctanoate ion (PFOA). When the experimental conditions were [PFOA]T = 2.86 × 10−3 mol L−1, [HCl]T = 0.66 mol L−1, and [Acetone]T = 2.86 vol %, 8.46 × 10−7 mol L−1 (1.14 ppm) of vitamin B12 was selectively extracted at 95.2% (sample solution; 35 mL → a liquid sedimented phase; 30 μL). This liquid sedimented phase consisted of large amounts of HPFOA. When microliter levels of THF and water were added to this sedimented phase, vitamin B12 is completely and rapidly back-extracted from the sedimented phase to the water phase. Vitamin B12 was then extracted into the water phase at 96.2% and all HPFOA remained in the sedimented phase. The rest of the sedimented phase after the back-extraction was dried and completely recovered as a powder of HPFOA. Consequently, this method was able to recycle HPFOA as a separation medium. Vitamin B12 in a water phase was also crystallized by the addition of excess THF. Moreover, this method was applied to the extraction from rare oysters. As a result, a few micrograms of vitamin B12 were recovered.
  • Keiko Nunokawa, Satoru Onaka, Tadashi Yamaguchi, Tasuku Ito, Seiji Wat ...
    Type: Short Articles
    Subject area: AI
    2003 Volume 76 Issue 8 Pages 1601-1602
    Published: 2003
    Released: August 15, 2003
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    A new Au11 cluster with (m-CF3C6H4)3P ligands has been synthesized and characterized by single crystal X-ray and XPS analysis. The cluster has an incomplete icosahedral skeleton similar to known Au11X3(PR3)7 clusters, but a stronger distortion from the ideal symmetry has been caused by introducing CF3 substituents at a meta-position of each phenyl ring of PR3 ligands.
  • Shinkiti Koto, Yoshika Shinoda, Motoko Hirooka, Akiko Sekino, Sachiko ...
    Type: Article
    Subject area: OB
    2003 Volume 76 Issue 8 Pages 1603-1615
    Published: 2003
    Released: August 15, 2003
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    O-β-D-Mannopyranosyl-(1→4)-O-α-D-mannopyranosyl-(1→3)-L-rhamnopyranose, a trisaccharide including a repeating unit of the O-specific polysaccharide (OSP) of Bulkholderia vietnamiensis strain LMG 6988, and O-(2-acetamido-2-deoxy-β-D-mannopyranosyl)-(1→4)-O-α-D-galactopyranosyl-(1→4)-D-galactopyranose, a trisaccharide including a repeating unit of OSP of Acinetobactor baumannii serogroup O18, were synthesized by means of in-situ-activating glycosylation using 2-O-acetyl-3,4,6-tri-O-benzyl-D-glucopyranose (2ATBG) and a reagent mixture of p-nitrobenzenesulfonyl chloride, silver triflate, and 1,8-diazabicyclo[5.4.0]undec-7-ene, and related systems. New syntheses of 2ATBG, allyl 2,3,6-tri-O-benzyl-α-D-galactopyranoside, benzyl 2,3,6-tri-O-benzyl-α-D-galactopyranoside, and 2-azido-3,4,6-tri-O-benzyl-2-deoxy-D-mannopyranose are described.
  • Katsuhiko Minoura, Koji Tomoo, Toshimasa Ishida, Hiroshi Hasegawa, Mas ...
    Type: Article
    Subject area: OB
    2003 Volume 76 Issue 8 Pages 1617-1624
    Published: 2003
    Released: August 15, 2003
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    The third repeat fragment (3MBD, 31 residues) in the four-repeat microtubule-binding domain of tau protein is considered to be responsible for the formation of the neuropathological filament. To clarify the structural function of 3MBD in the filamentous assembly, solution structures in water and 2,2,2-trifluoroethanol (TFE) were investigated by CD measurement and the combination of two-dimensional 1H-NMR measurement and a molecular modeling calculation. The CD spectra suggested the solvent-dependent conformation of 3MBD, i.e., random and α-helical structures in water and TFE solvents, respectively. All protons were assigned by various 2D NMR spectral measurements. The NOE pattern characteristic of a typical helical structure was observed in TFE solution. Using NOE and JHNCαH data observed in both solutions, possible 3D structures were generated by the dynamical simulated annealing method. The constructed NMR conformers in water consisted of an equilibrium mixture of extended and folded conformers, although the N-terminal Val1–Lys6 and middle fragments formed well-refined extended (Val1–Lys6) and α-helical (Leu10–Leu20) structures in TFE, respectively. Interestingly, the helical structure showed an amphipathic distribution of the respective side chains. This amphipathic behaviour of the 3MBD structure is advantageous for self-association through the alternating hydrophilic and hydrophobic interactions into a helical filament of the tau MBD domain. Based on the situation-dependent conformational flexibility of 3MBD, the possibility of filament formation of tau protein via self-assembly of the α-helical structure under neuropathological conditions is discussed.
  • Kyoko Yagi, Masahiro Irie
    Type: Article
    Subject area: OB
    2003 Volume 76 Issue 8 Pages 1625-1628
    Published: 2003
    Released: August 15, 2003
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    Diarylethenes having a fluorescent indole ring as the aryl group 1a and 2a were synthesized. Upon alternate irradiation with 366 nm and visible (λ > 480 nm) light, 1a underwent reversible photocyclization reactions to produce closed-ring isomer 1b. The fluorescence intensity also reversibly changed along with the reactions. The fluorescence quantum yields of the open-ring isomers 1a and 2a were 4.6 and 6.3% respectively, while the yields of the closed-ring isomers 1b and 2b were almost zero. The fluorescence quantum yields decreased with the increase in the photocyclization quantum yields.
  • Hiroyuki Chiba, Setsuo Funasaka, Teruaki Mukaiyama
    Type: Article
    Subject area: OB
    2003 Volume 76 Issue 8 Pages 1629-1644
    Published: 2003
    Released: August 15, 2003
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    A novel and efficient glycosyl donor having a p-trifluoromethylbenzylthio-N-p-trifluoromethylphenylformimidate group at an anomeric position is easily prepared by the addition of anomeric hydroxy group of 2,3,4,6-tetra-O-benzyl-α,β-D-glucopyranose to p-trifluoromethylphenyl isothiocyanate, followed by treatment with p-trifluoromethylbenzyl bromide. Catalytic and stereoselective glycosylation of various glycosyl acceptors with the above glycosyl donor smoothly proceeds by using various protic and Lewis acid catalysts which interact with its nitrogen atom. Further, catalytic and highly 1,2-cis or 1,2-trans stereoselective and chemoselective glycosylation between two different “armed” and “disarmed” glycosyl p-trifluoromethylbenzylthio-N-p-trifluoromethylphenylformimidates is also performed effectively in the presence of a catalytic amount of trifluoromethanesulfonic acid (TfOH) at −78 °C in tBuOMe or EtCN, respectively. These glycosylations are applied to successful one-pot sequential syntheses of trisaccharides.
  • Taichi Shintou, Wataru Kikuchi, Teruaki Mukaiyama
    Type: Article
    Subject area: OB
    2003 Volume 76 Issue 8 Pages 1645-1667
    Published: 2003
    Released: August 15, 2003
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    A new-type of oxidation–reduction condensation proceeded smoothly to afford carboxylic acid alkyl esters or alkyl phenyl ethers in good to high yields by combined use of alkoxydiphenylphosphines (1) having primary, bulky secondary or tertiary alkoxy groups, a mild quinone-type oxidant such as 2,6-dimethyl-1,4-benzoquinone (DMBQ) and carboxylic acids or phenols. Generally, alkoxydiphenylphosphines were prepared easily from chlorodiphenylphosphine (2) and alcohols in the presence of pyridine, and were isolated by distillation. On the other hand, the phosphines 1 were also prepared in situ from N,N-dimethylaminodiphenylphosphine (3a) and primary or secondary alcohols while primary, bulky secondary or tertiary alkoxydiphenylphosphines were alternatively formed in situ by adding 2 to the nBuLi-treated alcohols in order to perform the above reactions by a one-pot procedure from alcohols and nucleophiles. The reaction of thus formed 1, DMBQ and carboxylic acids or phenols afforded the corresponding alkylated products, including hindered secondary and tertiary alkylated ones, in good to high yields at room temperature. In the case of using chiral secondary alcohols, the corresponding carboxylic acid alkyl esters were obtained as well in high yields with perfect inversion of stereochemistry by SN2 replacement.
  • Yasujiro Murata, Mitsuharu Suzuki, Yves Rubin, Koichi Komatsu
    Type: Article
    Subject area: OB
    2003 Volume 76 Issue 8 Pages 1669-1672
    Published: 2003
    Released: August 15, 2003
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    A solid-state reaction of fullerene C60 with 3,6-di(2-pyridyl)-1,2,4,5-tetrazine using the high-speed vibration milling technique gives almost quantitatively the monoadduct 2, which is transformed in high yield upon contact with silica gel to a novel 1,2,3,4-tetrahydro-C60 derivative 3 having a 2-pyrazoline ring fused at unusual 2,3-positions of the C60 framework. This unexpected product is the result of the addition of a water molecule to an imine moiety of 2, followed by a series of rearrangements.
  • Mohammad Ali Zolfigol, Peyman Salehi, Shadpour E. Mallakpour, Mehdi To ...
    Type: Short Articles
    Subject area: OB
    2003 Volume 76 Issue 8 Pages 1673-1674
    Published: 2003
    Released: August 15, 2003
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    A combination of inorganic hydrolyzable chloride salts and 1,4-diazabicyclo[2.2.2]octane 1,4-bis(oxide)-bis(hydrogen peroxide), DABCO-DNODP, in the presence of wet SiO2 is used as an effective oxidizing agent for the oxidation of urazoles and bis-urazoles to their corresponding triazolinediones under mild and heterogeneous conditions with good to excellent yields.
  • Kentaro Okuma, Osami Sakai, Kosei Shioji
    Type: Short Articles
    Subject area: OB
    2003 Volume 76 Issue 8 Pages 1675-1676
    Published: 2003
    Released: August 15, 2003
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    The reaction of methyltriphenylphosphonium bromide with DBU in refluxing dichloromethane or toluene afforded methylenetriphenylphosphorane, which further reacted with benzaldehydes to give styrenes in good yields. Semistabilized ylide, benzylidenetriphenylphosphorane was also synthesized by using DBU, which reacted with aldehydes to afford olefins in nearly quantitative yields.
  • Tsugio Kitamura, Yusuke Ishida, Teizo Yamaji, Yuzo Fujiwara
    Type: Short Articles
    Subject area: OB
    2003 Volume 76 Issue 8 Pages 1677-1678
    Published: 2003
    Released: August 15, 2003
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    In trifluoroacetic acid (TFA), methane and CO can be converted to acetic acid by a new catalytic system, Mo/CaCl2/K2S2O8/TFA. The best result (89.4% of acetic acid) was obtained in a reaction of methane (20 atm) and CO (50 atm) using the catalytic system at 85 °C for 20 h.
  • Yoshiro Masuyama, Takehiro Sano, Michihito Oshima, Yasuhiko Kurusu
    Type: Short Articles
    Subject area: OB
    2003 Volume 76 Issue 8 Pages 1679-1680
    Published: 2003
    Released: August 15, 2003
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    2-Phenylthioallyl bromides, derived from allyl phenyl sulfides via dibromination, followed by dehydrobromination, cause the 2-phenylthioallylation of aldehydes with tin(II) iodide, tetrabutylammonium iodide and sodium iodide in 1,3-dimethylimidazolidin-2-one to produce the corresponding 1-substituted 3-phenylthiohomoallyl alcohols.
  • Yasuhiro Abe, Machiko Takigami, Kouji Sugino, Mitsumasa Taguchi, Takuj ...
    Type: Article
    Subject area: AM
    2003 Volume 76 Issue 8 Pages 1681-1685
    Published: 2003
    Released: August 15, 2003
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    The decomposition of phenolic endocrine disrupting chemicals (P-EDCs), such as phenol, 4-t-butylphenol (BuP), and bisphenol A (BPA), in aqueous solutions by potassium permanganate (KMnO4) was studied, and its efficiency was compared with that of hydroxyl radicals (OH) generated by 60Co γ-ray irradiation. Various organic acids and inorganic carbon were formed in the decomposition of P-EDCs due to either KMnO4 or OH. They were formed via direct aromatic ring cleavage in the case of KMnO4 and via OH addition-substitution reactions, followed by aromatic ring cleavage, in the case of OH. Comparing the decrease in the P-EDCs based on the number of electrons, the amount of KMnO4 spent to completely eliminate BuP and BPA was comparable to that of OH. Although three-times more KMnO4 was needed for phenol decomposition than OH, the complete conversion of phenol into organic acids and inorganic carbon was achieved with 720 μM of electrons in both cases.
  • Dong-Ki Keum, Kensuke Naka, Yoshiki Chujo
    Type: Article
    Subject area: AM
    2003 Volume 76 Issue 8 Pages 1687-1691
    Published: 2003
    Released: August 15, 2003
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    We examined the crystallization of CaCO3 by changing the time of addition of the G1.5 and G3.5 poly(amidoamine) dendrimers to a calcium carbonate solution after incubation for several minutes (1, 3, 20, or 60 min) at 30 °C. Based on the fact that the crystal phase obtained in the absence of the dendrimer was calcite, the dendrimers effectively stabilized the most unstable vaterite particles, even delaying the addition time of the dendrimer for 60 min. As the delayed addition time of the G1.5 dendrimer increased from 0 to 60 min, the particle size increased from 1.2 ± 0.5 to 4.7 ± 0.7 μm. As the generation number of the dendrimer increased from G1.5 to G3.5, the particle size of the spherical vaterite decreased under the same condition. The present results suggest that the anionic PAMAM dendrimers effectively modified the metastable vaterite surface and inhibited the further growth of vaterite particles by changing the addition time.
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