Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 73 , Issue 12
Showing 1-29 articles out of 29 articles from the selected issue
  • Kyuya Yakushi
    2000 Volume 73 Issue 12 Pages 2643-2662
    Published: 2000
    Released: December 27, 2001
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    The author reviews the low-energy optical transitions in quasi one- and two-dimensional organic conductors studied by polarized reflection spectroscopy. The characteristic optical properties of organic conductors are the strong anisotropy, electron-electron interaction, and coupling with intra-molecular vibration. The method to extract the transfer integrals in anisotropic tight-binding bands is described for several organic conductors. The correlation effect has a big influence on the line shape of the optical conductivity spectrum in the intra-band transition region. The electron-molecular vibration coupling provides us with rich information on the structural fluctuations and structural changes during the phase transition. The observation of plasmons resulting from the mixing with the transverse excitation is caused by the strong anisotropy in electronic structure.
  • Yutaka Amao, Ichiro Okura, Tokuji Miyashita
    2000 Volume 73 Issue 12 Pages 2663-2668
    Published: 2000
    Released: December 27, 2001
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    New optical oxygen sensors based on the luminescence intensities of four different europium(III) complexes, ((1,10-phenanthroline)tris(thenoyltrifluoroacetonato)europium(III) complex ([Eu(tta)3phen]), tris(thenoyltrifluoroacetonato)europium(III) dihydrate ([Eu(tta)3]·2H2O), tris(1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedionato)europium(III) complex ([Eu(pta)3]·2H2O) and tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionato)europium(III) complex ([Eu(fod)3]·2H2O)) immobilized in poly(styrene-co-2,2,2-trifluoroethyl methacrylate) (poly-(styrene-co-TFEM)) films were developed. The luminescence intensity of the europium(III) complex films decreased with increasing the oxygen concentration. Stern-Volmer plots of the europium(III) complex films exhibited considerable linearity. The KSV values of [Eu(tta)3phen], [Eu(tta)3]·2H2O, [Eu(pta)3]·2H2O and [Eu(fod)3]·2H2O in films were estimated to be 0.015, 0.005, 0.002 and 0.003 %-1, respectively. The large KSV value of the [Eu(tta)3phen] film was obtained compared with the other europium(III) complexes. The response times of the europium(III) complex films are 6.7 s for [Eu(tta)3phen], 6.7 s for [Eu(tta)3]·2H2O, 6.6 s for [Eu(pta)3]·2H2O and 7.6 s for [Eu(fod)3]·2H2O on going from argon to oxygen and 7.0 s for [Eu(tta)3phen], 7.5 s for [Eu(tta)3]·2H2O, 8.1 s for [Eu(pta)3]·2H2O and 8.6 s for [Eu(fod)3]·2H2O on going from oxygen to argon, respectively. A highly sensitive oxygen sensor using [Eu(tta)3phen] immobilized in poly-(styrene-co-TFEM) film has been developed.
  • Kazunari Yoshizawa, Yoshihito Shiota, Yoshihisa Kagawa
    2000 Volume 73 Issue 12 Pages 2669-2673
    Published: 2000
    Released: December 27, 2001
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    Density-functional-theory calculational results on the reaction pathway for alkane hydroxylation by a compound I model of cytochrome P450 are discussed. Our calculations demonstrate that the transition state for the H-atom abstraction of ethane involves a linear (Fe)O…H…C array and that the resultant carbon radical is bound to the iron-hydroxo species. This comptational result is partly consistent with the oxygen rebound mechanism in that the direct H-atom abstraction by the iron-oxo species takes place in the initial stages of the reaction pathway. However, the iron-hydroxo species cannot be viewed as a stable reaction intermediate in view of the energy diagram. Our results may not be consistent with the model of a free radical species with a finite lifetime and barrier to displacement of the OH group from the iron center that is commonly assumed and typically stated for the oxygen rebound mechanism.
  • Hiroshi Yao, Osamu Momozawa, Tomoki Hamatani, Keisaku Kimura
    2000 Volume 73 Issue 12 Pages 2675-2678
    Published: 2000
    Released: December 27, 2001
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    The transfer of surface-modified gold nanoparticles across a water/toluene interface was demonstrated. Stoichiometric ion-pair formation between carboxylate anions on particle surfaces and tetraoctylammonium cations brought about the phase transfer, and was revealed by transmission electron microscopy (TEM), IR, UV-vis absorption, and energy dispersive X-ray (EDX) spectroscopies. A surface structure of the transferred gold nanoparticles was also presented. During the nanoparticle transfer from water into an organic phase, an improvement in the dispersibility and a slight decrease in the average diameter were observed (3.6 → 2.9 nm) accompanied by a slight narrowing in the size distribution (standard deviation: 0.80 → 0.54 nm). The phenomena could lead to a new methodology for size and/or dispersibility selections.
  • Shinsaku Fujita
    2000 Volume 73 Issue 12 Pages 2679-2685
    Published: 2000
    Released: December 27, 2001
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    For the design of chiral molecules of high symmetry, a set of substitution positions in an achiral skeleton of G-symmetry are replaced by chiral ligands or proligands of the same kind so that there emerge three criteria of generating chiral molecules or promolecules. Thus, Criterion 1 controls the desymmetrization of a homospheric orbit in an achiral skeleton, where the resulting molecule or promolecule is determined to belong to the maximum chiral subgroup of G in agreement with a size-invariant subduction. Criterion 2 for the desymmetrization of an enantiospheric orbit shows that the resulting molecule or promolecule is determined to belong to the maximum chiral subgroup of G and that the original enantiospheric orbits are divided into two hemispheric orbits of equal size. Criterion 3 deals with a chiral skeleton, where subsitution by chiral ligands or proligands of the same kind is examined as the transformation of the hemispheric orbit in the skeleton. Although no change of symmetry occurs from a group-theoretical point of view, the transformation is shown to be important chemically, since relevant ligands or proligands alter the stereochemical properties.
  • Yuki Yamasaki, Heiji Enomoto, Nakamichi Yamasaki, Masaru Nakahara
    2000 Volume 73 Issue 12 Pages 2687-2693
    Published: 2000
    Released: December 27, 2001
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    Hydrothermal reactions of considerably concentrated (ca. 1 M; M = mol dm-3) dichloromethane, CH2Cl2, were investigated with and without alkali in the temperature range of 150—300 °C by using batch reactors, such as an autoclave and sealed glass tubes. 1H, 2H, and 13C NMR spectra were taken at room temperature as a function of reaction time to analyze the quenched reactants, intermediates, and products. In the presence of NaOH at 2 M, the complete dechlorination was achieved in 270 min at 250 °C and in 60 min at 300 °C. Such gaseous by-products as CO, CO2, and H2 were generated by the decomposition of the disproportionation product, HCOO-. Without alkali, CH2(OH)2 could be detected by 1H and 13C NMR as an intermediate in the hydrolysis of CH2Cl2, before such Cannizzaro products as methanol and formate ion were formed. The mechanism of the hydrothermal reactions of CH2Cl2 is discussed in terms of the hydrolysis intermediate, CH2(OH)2.
  • Kazuhide Tsuji, Kiyoshi Nakata, Hirotada Oishi, Kazuhiko Shibuya
    2000 Volume 73 Issue 12 Pages 2695-2702
    Published: 2000
    Released: December 27, 2001
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    We have applied an infrared-ultraviolet double resonance laser-induced fluorescence (IR-UV LIF) technique to the measurement of OH concentrations in the troposphere. This OH exists in extremely low concentrations, ca. 106 molecules cm-3, and plays a central role in the atmospheric chemistry. The detection limit of this new technique using our laser and detection system was experimentally determined to be 1.3×109 molecules cm-3 at 9.2 mTorr in Ar buffer gas. We have found that the method is free from chemical interferences but less sensitive than the single photon LIF method. A simple model is formulated and differential equations are numerically solved after the selection and determination of necessary physical constants. The method leads to the simulated (single photon LIF)/(IR-UV LIF) sensitivity ratio of 1.4×103, comparable with the experimental value of 2.2×103. On the basis of the proposed kinetic model, we discuss the optimum experimental parameters (sample pressure, IR and UV laser powers, and delay time) in this IR-UV LIF method by taking account of rotational energy transfer, fluorescence quenching, and saturation of absorption.
  • Yuki Tanaka, Masaharu Tsuji, Yukio Nishimura
    2000 Volume 73 Issue 12 Pages 2703-2712
    Published: 2000
    Released: December 27, 2001
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    Chemical ionization of n-paraffins (CxH2x+2: x = 8—18) by the CH5+, C2H5+, and C3H5+ ions has been studied under a reactant-ion selective mode of an ion-trap type of GC/MS. In all the reactions, (MW-1)+ = CxH2x+1+ and fragment alkyl CyH2y+1+ (y = 3—x - 3) ions were observed. The dependence of the relative intensities of CxH2x+1+ and CyH2y+1+ on the reaction time indicated that collisional stabilization takes part in the formation of product ions. The dependence of CxH2x+1+ and CyH2y+1+ distributions on the reactant hydrocarbon ions and reagent chain length was examined. The reaction mechanism was discussed from the observed product-ion distributions and heats of reactions of each pathway.
  • Kazuya Saito, Yasuhisa Yamamura, Michio Sorai
    2000 Volume 73 Issue 12 Pages 2713-2718
    Published: 2000
    Released: December 27, 2001
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    The heat capacity of crystalline p-quinquephenyl was measured by adiabatic calorimetry below room temperature. A broad hump was detected around 264 K and attributed to a phase transition, through which an average molecular conformation changes from the planar to the twisted one on cooling. A similar anomaly was also detected for crystalline p-sexiphenyl around 295 K by chopped-light ac calorimetry. The broad shape of the thermal anomalies arising from the twist transitions are discussed in relation to the number of possible intramolecular twisting modes. Properties of the twist transition in polymer are discussed on the basis of those of oligomers. Standard thermodynamic functions are tabulated for p-quinquephenyl.
  • Koichi Hirota, Hidehiko Arai, Shoji Hashimoto
    2000 Volume 73 Issue 12 Pages 2719-2724
    Published: 2000
    Released: December 27, 2001
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    Carbon tetrachloride (CCl4, approximately 10, 50, and 100 ppm) in air and nitrogen was irradiated with electron beams in both the presence and absence of water. The absorbed doses ranged from 1.2 to 18.0 kGys. An absorbed dose of 18 kGy led to approximately 90% decomposition of CCl4 at a concentration of 10 ppm in dry air. The presence of water lowered the decomposition rate in air by 20%, but not in nitrogen. Negative oxygen ions (O2-) formed upon the irradiation of wet air played a role in the oxidation of CCl4. Water molecules became negative cluster ions (O2-(H2O)n) with negative oxygen ions, which depressed the oxidation.
  • Tsutomu Ishioka, Noriko Matsuda, Yasuyuki Kitagawa, Kazuo T. Nakamura
    2000 Volume 73 Issue 12 Pages 2725-2726
    Published: 2000
    Released: December 27, 2001
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    The crystal structure of N,N-distearyl-1,4-diazabicyclo[2.2.2]octane dibromide is orthorhombic (Pna21) with a = 63.851(9), b = 9.156(7), c = 8.366(6) Å and Z = 4.
  • Noriaki Funasaki, Masao Nomura, Hiroshi Yamaguchi, Seiji Ishikawa, Sab ...
    2000 Volume 73 Issue 12 Pages 2727-2728
    Published: 2000
    Released: December 27, 2001
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    Sodium methanesulfonate and sodium methyl sulfate are good internal references for chemical shift determination in aqueous solutions containing cyclodextrin and anionic guests. The chemical shift, referred to external standard and corrected by adding a term proportional to the cyclodextrin concentration, is in excellent agreement with that obtained using internal standard.
  • Takashi Fukuda, Akira Yamauchi
    2000 Volume 73 Issue 12 Pages 2729-2732
    Published: 2000
    Released: December 27, 2001
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    Several characteristics on a charged mosaic membrane with parallel arrays of different negative and positive charges were investigated through transport studies. In particular, the transport behaviors of three different amino acids (GluNa, Arg, and Ala), known as amphoteric electrolytes, were examined in contrast to those of the simple electrolytes (KCl and LiCl). From an analysis of the data of the volume flux and salt flux, although preferential amino acid transport across the charged mosaic membrane was observed, the extent of the permeability was less than that of simple salt. Among amino acids, GluNa with almost complete dissociation indicated the maximum permeability. A conductance study indicated that the transport behaviors were dependent on the ionic states in aqueous solution. It was inferred that amino acids with apparent zero net charges have transport behaviors different from a nonelectrolyte, such as sucrose.
  • Wei-Yin Sun, Bao-Li Fei, Taka-aki Okamura, Yan-An Zhang, Tao Ye, Wen-X ...
    2000 Volume 73 Issue 12 Pages 2733-2738
    Published: 2000
    Released: December 27, 2001
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    Mononuclear complexes, [M(cbim)4(NO3)2] [M = Cd(II) (1), Co(II) (2) and Ni(II) (3); cbim = 4–cyanobenzyl–1–imidazole], were synthesized and their structures were determined by X-ray crystallography. Each metal atom is coordinated by four N atoms of imidazole from four cbim ligands and two O atoms of two nitrate anions with distorted octahedral coordination geometry. All three complexes crystallize in triclinic with space group P1. There are C-H···O, C-H···N hydrogen bonds and π-π interactions in the crystal packing of complexes 1, 2, and 3. The compounds were also characterized by 1H and 113Cd NMR spectroscopy. Highly isotropic shifted signals were observed in the 1H NMR spectra of complexes 2 and 3 due to the paramagnetic property of the high-spin Co(II) and Ni(II) cores.
  • Yasuki Yoshimura
    2000 Volume 73 Issue 12 Pages 2739-2746
    Published: 2000
    Released: December 27, 2001
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    In order to examine the role of activated α-carbon atom hydrogen of α-amino acid in the salt effect on tris(α-amino acidato)cobalt(III) ([Co(aa)3]), the solubilities of mer- and fac-tris(2-aminoisobutyrato)cobalt(III) (mer- and fac-[Co(aiba)3]) in water and in aqueous NaBr and tetrabutylammonium bromide (Bu4NBr) solutions were determined over the temperature range 5 to 40 °C. From these solubility data, the standard enthalpy (ΔtrH0) and entropy of transfer (ΔtrS0) at 25 °C for mer- and fac-[Co(aiba)3] from water to the aqueous NaBr and Bu4NBr solutions were estimated. A comparison with the ΔtrH0 and TΔtrS0 data for mer-[Co(aa)3] of L-leucine (leuH), L-alanine (alaH), and glycine (glyH) shows that both ΔtrH0 and TΔtrS0 for the transfer of mer-[Co(aa)3] to the NaBr solutions are negative; the large negative ΔtrH0 increases the solubility of mer-[Co(aa)3] (salting-in effect). Both ΔtrH0 and TΔtrS0 decrease in the order of mer–[Co(aiba)3] > mer–(+)–[Co(L–leu)3] > mer–(+)–[Co(L–ala)3] > mer–[Co(gly)3]. This sequence is explained by the assumption that activated α-carbon atom hydrogen enhances interactions of mer-[Co(aa)3] with the surroundings. The effect of Bu4NBr can be accounted for by hydrophobic interaction of [Co(aiba)3] with Bu4N+ ion and the hydrophobic interaction of fac-[Co(aiba)3] is larger than the interaction of mer-[Co(aiba)3].
  • Hajime Tanida, Iwao Watanabe
    2000 Volume 73 Issue 12 Pages 2747-2752
    Published: 2000
    Released: December 27, 2001
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    X-ray absorption spectra of I K-edge have been obtained for iodide ions dissolved in various solvents. Oscillation amplitudes of the extended X-ray absorption fine structure (EXAFS) evaluated from the peak intensities in the Fourier-transform spectra were found to correlate with the Mayer-Gutmann acceptor number (AN) of solvents studied. The correlation is quite similar to that for bromide ions, which has already been reported by the same authors (H. Tanida, H. Sakane, and I. Watanabe, J. Chem. Soc., Dalton Trans., 1994, 2321). Such results confirm that the EXAFS method is not only a tool to determine geometrical structures in liquids, but can also be used for evaluating solute-solvent interaction strength, similarly to AN. The I…O distances in protic solvents and I…C in aprotic solvents were determined to be 3.4—3.5 and 3.7—3.8 Å, respectively. In protic solvents, the larger the AN values, the shorter the I…O distances and the larger the co-ordination numbers of I-, which were determined to be 1—4. In aprotic solvents, the co-ordination numbers of I- were found to be 4—8. It seems that aprotic solvents having two methyl groups in a molecule are able to solvate I- through two methyl groups, which is similar to the conclusion reported for Br-.
  • Isao Ando, Hiroto Miyake, Yusuke Ohki, Kikujiro Ujimoto, Hirondo Kurih ...
    2000 Volume 73 Issue 12 Pages 2753-2757
    Published: 2000
    Released: December 27, 2001
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    A cyclic voltammogram of 1,4-benzoquinone showed a couple of redox waves in aqueous solution. Upon adding a trace amount of silver ion, the cyclic voltammogram exhibited an anomalous behavior: a shift of the reduction peak toward a negative potential and the appearance of a new re-oxidation peak at a much more positive potential. This anomalous electrochemical behavior was investigated in terms of both interactions in bulk and on the electrode surface using some kinds of metal-ion additives and some working-electrode materials. It is suggested that the underpotential deposition of silver ion is primarily responsible for the anomalous electrochemical behavior of 1,4-benzoquinone. This was demonstrated by a measurement of cyclic voltammograms using a silver-deposited electrode at an underpotential.
  • Saburo Neya, Yoshiki Ohgo, Mikio Nakamura, Noriaki Funasaki
    2000 Volume 73 Issue 12 Pages 2759-2765
    Published: 2000
    Released: December 27, 2001
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    The coordination behaviors of chloro corrphycenatoiron(III), a novel hemin isomer with a trapezoidal metallo core, against imidazole, 1-methylimidazole, and 2-methylimidazole were followed by spectrophotometry in chloroform at room temperature. The examined compound is chloro 12,17-bis(ethoxycarbonyl)-2,3,6,7,11,18-hexamethylcorrphycenatoiron(III). Titration of 2-methylimidazole and imidazole proceeded with and without accumulation of an intermediate mono imidazole species, respectively. On the other hand, a significant amount of an intermediate adduct was found to accumulate during 1-methylimidazole binding despite the absence of any steric hindrance in the iron(III)-N(1-methylimidazole) coordination bond. This is in remarkable contrast with the conventional results for porphyrinatoiron(III). The proton NMR analysis of the mono 1-methylimidazole binding to corrphycenatoiron(III) afforded a formation constant closely similar to that obtained from the visible spectra. EPR definitely assigned the iron(III) high-spin state for the intermediate. Accumulation of the mono 1-methylimidazole intermediate was explained in terms of the contracted core in corrphycene. The narrow iron cavity weakens the axial iron-chloride bond facilitating coordination of the first 1-methylimidazole. The four non-orthogonal iron(III)-N(pyrrole) bonds formed in the trapezoidal cavity further disturb the incoming motion of the iron(III) atom into corrphycene plane upon second 1-methylimidazole ligation. Accumulation of mono 1-methylimidazole intermediate was more evident in ferric corrphycenatoiron(III) with bromide and iodide, supporting the proposed changes in iron reactivity upon deformation of the equatorial coordination environment.
  • Takumi Konno, Keiji Tokuda, Junko Sakurai, Ken-ichi Okamoto
    2000 Volume 73 Issue 12 Pages 2767-2773
    Published: 2000
    Released: December 27, 2001
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    An S-bridged CoIIICdII dinuclear complex molecule, [CdCl3{Co(aet)2(en)}]0 ([1]) (aet = 2–aminoethanethiolate, en = ethylenediamine), was prepared by the reaction of an S-bridged CoIIINiIICoIII trinuclear complex salt, [Ni{Co(aet)2(en)}2]Cl4, with excess CdCl2 in water. Treatment of [1] with NaNO3 in water gave an S-bridged CoIIICdIICoIII dinuclear complex salt, [CdCl{Co(aet)2(en)}2](NO3)3 ([2](NO3)3), which was further converted to a (CoIIICdIICoIII)2 hexanuclear complex salt, [Cd2Cl{Co(aet)2(en)}4](NO3)7 ([3](NO3)7), by treatment with NaNO3 in water. The crystal structures of [1], [2](NO3)3 and [3](NO3)7 were determined by X-ray crystallography. In [1] CdII ion is coordinated by three Cl- ions besides two S atoms from one octahedral C2-cis(S)-[Co(aet)2(en)]+ unit, while each CdII ion in [2]3+ and [3]7+ is coordinated by one Cl- ion besides four S atoms from two C2-cis(S)-[Co(aet)2(en)]+ units. The coordination geometry of each CdII center in [1], [2]3+ and [3]7+ is described as a distorted trigonal-bipyramid, considering an angular structural parameter, χ, which is proposed as a modified index of trigonality. The reverse conversions of [3]7+ to [2]3+ and [2]3+ to [1] were also achieved by treatment with NaCl in water.
  • Iraj Mohammadpoor-Baltork, Mohammad Kazem Amini, Siyamak Farshidipoor
    2000 Volume 73 Issue 12 Pages 2775-2778
    Published: 2000
    Released: December 27, 2001
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    An efficient and selective method for the deprotection of trimethylsilyl (TMS) and tetrahydropyranyl (THP) ethers, ethylene acetals and ketals to their corresponding alcohols and carbonyl compounds using oxone in refluxing acetonitrile is described. Excellent chemoselectivity of this method makes it a useful and practical procedure in organic synthesis.
  • Yutaka Nishiyama, Fujio Kakushou, Noboru Sonoda
    2000 Volume 73 Issue 12 Pages 2779-2782
    Published: 2000
    Released: December 27, 2001
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    Rhenium complexes have been shown to catalyze the alkylation of arenes with alkyl halides. When arenes were reacted with an alkyl chloride in the presence of a catalytic amount of rhenium complexes, such as bromopentacarbonylrhenium(I) [ReBr(CO)5], tricarbonylcyclopentadienylrhenium(I) [Re(C5H5)(CO)3] and decacarbonyldirhenium [Re2(CO)10], alkylation of the arenes proceeded under mild conditions to give a mixture of mono- and dialkyl substituted arenes in moderate-to-good yields.
  • Shingo Ikeda, Shigeru Murata, Kunihiko Ishii, Hiro-o Hamaguchi
    2000 Volume 73 Issue 12 Pages 2783-2792
    Published: 2000
    Released: December 27, 2001
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    The processes of the pyrene-sensitized photodecomposition of N-phenylglycine (NPG) have been investigated by fluorescence quenching experiments, laser flash photolysis studies, and characterization of the reaction products. A mechanism involving electron transfer from NPG to singlet excited pyrene through emissive exciplex formation, as well as the intervention of PhNHCH2· as a reactive intermediate, has been established. The efficiency of NPG photodecomposition is enhanced by the addition of an electron acceptor, such as terephthalonitrile or diethyl isophthalate. The laser flash photolysis studies have revealed that the mechanism for the rate enhancement of NPG photodecomposition depends on the acceptor employed as an additive.
  • Yun-Shan Lin, Shih-Jue Lin, Shuan-Ya Jiang, Tian-Chyuan Huang, Chien-Y ...
    2000 Volume 73 Issue 12 Pages 2793-2803
    Published: 2000
    Released: December 27, 2001
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    The lead(IV) oxide oxidation of various azulen-2-ol derivatives in acetic acid generates azulenoxy radicals via one-electron oxidation. The intermediates end up yielding recombined dimers, [1,1-biazulene]-2,2(1H,1H)-dimers, as common type of products. In addition to these, hexacyclic cage dimers were obtained from 5-substituted azulen-2-ol derivatives. From dimethyl 2-hydroxyazulene-1,3-dicarboxylate, a hydroxyazulene having no substituent on the seven-membered ring was isolated a pair of dimethyl 2-hydroxy-4-[1,3-di(methoxycarbonyl)-2-oxo-1,2-dihydroazulenyl]azulene-1,3-dicarboxylate, but neither a cage dimer nor a 1,6-coupled dimer. The full structures of the dimers have been firmly established by an extensive X-ray crystallographic analysis and 13C NMR spectral comparisons of the key derivatives. Concerning the mechanism of the formation of the cage dimers, a [5+5] π cycloaddition followed by recombination of the resultant biallyl system is suggested.
  • Kazuhiro Kobayashi, Takeshi Matoba, Susumu Irisawa, Atsushi Takanohash ...
    2000 Volume 73 Issue 12 Pages 2805-2809
    Published: 2000
    Released: December 27, 2001
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    The direct synthesis of the title amino acid derivatives from carboxylic esters and nitrones can be achieved in fair to good yields when lithium or magnesium ester enolates were treated with nitrones in THF at -78 °C or in Et2O at -20 to 0 °C, respectively. The products from the reaction of t-butyl acetate with 3,4-dihydroisoquinoline N-oxide or 5,5-dimethylpyrroline 1-oxide were transformed into (1,2,3,4-tetrahydroisoquinolin-1-ylidene)acetate or (pyrrolidin-2-ylidene)acetate derivatives in the presence of triphenylphosphine, carbon tetrachloride, and triethylamine in refluxing dichloromethane.
  • Isamu Shiina, Yoshihito Suenaga, Masakazu Nakano, Teruaki Mukaiyama
    2000 Volume 73 Issue 12 Pages 2811-2818
    Published: 2000
    Released: December 27, 2001
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    Preparations of carboxamides and peptides are performed in high yields from free carboxylic acids and amines by dehydration condensation using di(2-pyridyl) carbonate (DPC) or O,O-di(2-pyridyl) thiocarbonate (DPTC) in the presence of a catalytic amount of 4-(dimethylamino)pyridine (DMAP). The formation of 2-pyridyl esters, key intermediates of the reaction, from carboxylic acids by using DPC proceeded faster than by using DPTC; therefore, the former carbonate is more efficiently employed in the above condensation reactions.
  • Shinobu Oda, Takeshi Sugai, Hiromichi Ohta
    2000 Volume 73 Issue 12 Pages 2819-2823
    Published: 2000
    Released: December 27, 2001
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    We have already reported that (RS)-citronellol [(RS)-1] can be optically resolved via a transacetylation with acetyl coenzyme A [acetyl-CoA] by the aid of alcohol acetyltransferase [AATFase] in Pichia kluyveri IFO 1165, which we have referred to as a double coupling system (E value, 30 to 40). In this system, although (R)-1 is obtained at over 98% ee, (S)-citronellyl acetate [(S)-2] is prepared at 70 to 80% ee. In this article, we report on the conversion of (R)-1 to (R)-citronellal [(R)-3] and (R)-citronellic acid [(R)-4] in high yield without racemization by the aid of Rhodococcus equi JCM 6817 and Geotrichum candidum JCM 01747, respectively. On the other hand, the low ee of (S)-1 (78% ee) prepared via the alkaline hydrolysis of (S)-2 is converted to optically active (S)-1 and (S)-4 in high yield with a repeated double coupling system with P. kluyveri IFO 1165 and via enantioselective oxidation with Candida viswanathii IFO 10321, respectively. Thus, five optically active terpenoids related to citronellol, except for (S)-3, were efficiently synthesized via microbial transformations in an interface bioreactor.
  • Itaru Sato, Yoshiko Takizawa, Kenso Soai
    2000 Volume 73 Issue 12 Pages 2825-2826
    Published: 2000
    Released: December 27, 2001
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    Diisopropylzinc is found to be a highly efficient reagent for the formation of zinc enolate equivalents from various iodoacetates via iodine-zinc exchange reaction at room temperature, affording β-hydroxy esters in high yields by the reaction with aldehydes and ketones.
  • Yoshio Furusho, Yuichiro Okada, Toshikazu Takata
    2000 Volume 73 Issue 12 Pages 2827-2828
    Published: 2000
    Released: December 27, 2001
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    In the presence of an equimolar amount of FeCl3, sulfonimidoyl chlorides were allowed to react with aromatic compounds to give the corresponding sulfoximines. Structure of the sulfonimidoyl chlorides and the aromatic compounds had considerable influence on the yield of the sulfoximines.
  • Tomoyuki Itaya, Kenzo Inoue
    2000 Volume 73 Issue 12 Pages 2829-2833
    Published: 2000
    Released: December 27, 2001
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    The self-assembling of 2,2,4,4,6,6-hexakis(4-pyridylmethoxy)-2λ5, 4λ5, 6λ5-cyclotri(phosphazene) (PyPN) and 1,4-naphthalenedicarboxylic acid (DCN) in DMF gives needle-like crystals. From elemental analysis, the stoichiometry of the crystal was PyPN/DCN = 1 : 3. The FT-IR, fluorescence and X-ray diffraction data showed that the self-assemblies [PyPN·3(DCN)]n (1) formed by the hydrogen bonding with an alternating sequence of one PyPN and three DCN molecules take a cylindrical structure and are laterally packed into a hexagonal arrangement, where the naphthalene rings are placed to avoid steric congestion. The assembly 1 has an ability to include iodine molecules. From FT-Raman spectroscopy, the iodine in 1 was found to exist as a polyiodine linear I5- ion, indicating that the crystal of 1 has a tunnel-like void.
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