Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 65 , Issue 7
Showing 1-46 articles out of 46 articles from the selected issue
  • Kenichi Sakai, Yasunari Maekawa, Kazuhiko Saigo, Makoto Sukegawa, Hisa ...
    1992 Volume 65 Issue 7 Pages 1747-1750
    Published: 1992
    Released: July 15, 2006
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    In the optical resolution of α-methylbenzylamine (1) with mandelic acid (2), the dimeric derivative of 1, bis(α-methylbenzyl)amine (4), caused a habit modification of the diasteromeric salt, (R)-1·(R)-2 (3). The habit modification was strongly influenced by the stereochemistry of 4. Amine (R,R)-4 changed the morphology of the crystal of the diastereomeric salt, even at a concentration of 0.007 mol% of 3; the shape of the crystal became a hexagonal plate from a long hexagonal plate, whereas its stereoisomer ((R,S)-4) changed the morphology less than (R,R)-4, and (S,S)-4 did not change at all. The habit modification of 3 by 4 is discussed on the basis of the crystal growth mechanism while considering the stereochemistry of 4.
  • Kiyotaka Oyama, Mikio Itoh, Yuji Nonaka
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1751-1754
    Published: 1992
    Released: July 15, 2006
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    A new method was studied for optical resolution of racemic amino acid esters by using, as resolving agents, N-protected L-α-aspartyl-L-phenylalanine alkyl esters, typically, N-benzyloxycarbonyl-L-α-aspartyl-L-phenylalanine methyl ester, the precursor to the synthetic sweetener aspartame. Thus, when the dipeptide and racemic amino acid ester were mixed in solvents, precipitation took place by formation of salt preferentially with D-amino acid ester to effect the optical resolution.
  • Tadahiro Motomura, Yasuhiro Aoyama
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1755-1760
    Published: 1992
    Released: July 15, 2006
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    Polycationic chitosan oligomers 1n (n = 2–6), i.e., β-1,4-linked glucosamine oligomers, were found to bind to nucleic acids in aqueous solutions at pH 7.2 via multiple electrostatic interaction. The binding of trimer and higher homologues (1n, n ≥ 3) is especially efficient owing to an (at least) three-point simultaneous ammonio phosphate formation. Upon binding of 1n (n ≥ 3), the double-helical structure in the A-form of poly(A)·poly(U), a synthetic RNA, is significantly stabilized as revealed by enhancement of its helix-to-coil transition (melting) temperatures. Upon binding of 1n (n ≥ 3), calf thymus DNA in the B-form undergoes a drastic conformational change to the A-form, as revealed by circular dichrosim spectroscopy. In marked contrast, chitosan dimer (12) and diamine and monoamine references only induce the B-to-C transition within the B-family. The significance of the multiple electrostatic interaction and the cooperativity of the glucosamine residues in 1n are discussed.
  • Takashi Matsumoto, Hiromitsu Terao, Natsuki Ishizuka, Shuji Usui, Hiro ...
    1992 Volume 65 Issue 7 Pages 1761-1770
    Published: 1992
    Released: July 15, 2006
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    All stereoisomers (4a,b7a,b) of 4-carboxy-4-ethyl-3-hydroxy-2-isopropyl-4-butanolide, the necic acid component of axillaridine, have been synthesized. Methyl(E)-(S)-(+)-2-ethyl-4-methoxycarbonyl-5-methyl-2- hexenoate (12a) was converted into γ-lactone acids, 4a (2S,3S,4S), 5a (2S,3R,4R), and 5b (2R,3S,4S), by a series of reactions: Epoxidation with m-chloroperbenzoic acid, treatment with acetone in the presence of tin(IV) chloride, acidic hydrolysis with formic acid, and alkaline hydrolysis with barium hydroxide. Similarly, (R)-(−)-enantiomer (12b) was also transformed into γ-lactone acids 4b (2R,3R,4R), 5b and 5a. Subsequently, (E)-(S)-(+)-4-carboxy-2-ethyl-5-methyl-2-hexenoic acid (13a) and its (R)-(−)-enantiomer (13b) were esterified with chloromethyl methyl ether in the presence of triethylamine to give the corresponding bis(methoxymethyl) esters (26a and 26b). Oxidation of 26a with potassium permanganate and subsequent acidic hydrolysis afforded γ-lactone acids, 6a (2S,3R,4S) and 7a (2S,3S,4R). Similarly, ester 26b was also converted into 6b (2R,3S,4R) and 7b (2R,3R,4S). The stereochemical courses of the above-mentioned trans- and cis-hydroxylations of olefinic esters (12a,b and 26a,b) were well explained by applying the Felkin–Anh model. The CD spectra of the synthetic 4a,b7a,b are also discussed.
  • Toshikazu Ibata, Yasushi Isogami, Hiroyuki Nakawa, Hatsue Tamura, Hiro ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1771-1778
    Published: 1992
    Released: July 15, 2006
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    The reaction of 2-alkyl- or 2-aryl-substituted 5-methoxy-4-(p-nitrophenyl)oxazoles with tetracyanoethylene gave methyl esters of 5-substituted 3,3,4,4-tetracyano-2-(p-nitrophenyl)-3,4-dihydro-2H-pyrrole-2-carboxylic acids as formal [3 + 2] cycloadducts through oxazole ring opening. Zwitterionic mechanisms were proposed on the basis of the solvent effect on the reaction. The molecular structure of 2-isopropyl-substituted product was determined by means of X-ray crystallography. Crystals of the cycloadduct are orthorhombic with space group Pcab having unit-cell dimensions of a = 17.998 (2), b = 27.188 (6), c = 15.833 (3) Å, and Z = 16, which contains two crystallographically independent molecules. The final R value is 0.070 for 4629 observed reflections.
  • Shigeru Futamura
    1992 Volume 65 Issue 7 Pages 1779-1783
    Published: 1992
    Released: July 15, 2006
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    The electron transfer photooxygenations of aromatic compounds were carried out with trityl salts. Under these superoxide-free reaction conditions, only anthracene and 1,1-diarylethylenes were photooxygenated, stilbenes isomerized, and quantitatively recovered were naphthalene, phenanthrene, alkylnaphthalenes, tetraphenylethylene and 1,1,4,4-tetraaryl-1,3-butadienes. The reactivities of their radical cations toward triplet oxygenation were discussed on the basis of the quantum yield measurements and product analyses.
  • Noritaka Abe, Yoshimasa Fukazawa, Yoshimasa Hirai, Tosio Sakurai, Kuni ...
    1992 Volume 65 Issue 7 Pages 1784-1793
    Published: 1992
    Released: July 15, 2006
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    The reactions of 2- and 8-(substituted amino)-1-azaazulenes with dimethyl acetylenedicarboxylate (DMAD) were investigated. Treatment of ethyl 2-acetylamino-1-azaazulene-3-carboxylate with DMAD in refluxing acetonitrile gave 9-ethyl 1,2,3-trimethyl 3a-azacyclopent[a]azulene-1,2,3,9-tetracarboxylate, 5-ethyl 1,2,2a,3-tetramethyl 4-acetyl-2a,3-dihydro-4H-4, 10b-diazapentaleno[1,6-aj]azulene-1,2,2a,3,5-pentacarboxylate (3a), and dimethyl (10-ethoxycarbonyl-4-methoxycarbonyl-2,4a-dihydro-2-oxo-2H-1,4a-diazabenz[a]azulen-3-yl)maleate. Compound 3a thermally rearranged to 9-ethyl 2,3,10,11-tetramethyl 1-acetyl-2,3,4,4a-tetrahydro-1H-1,4-diaza-3,4a-ethenofluorene-2,3,9,10,11-pentacarboxylate. The reaction of ethyl 2-alkylamino-1-azaazulene-3-carboxylate with DMAD gave the corresponding 4-alkyl-2a,3-dihydro-4H-4,10b-diazapentaleno[1,6-aj]azulene derivatives, and the etheno-bridged 1-azaheptalene derivative. The reaction of 8-ethylamino-3-phenyl-1-azaazulene with DMAD gave trimethyl 1-phenyl-2a-azabenz[cd]azulene-3,4,5-tricarboxylate, tetramethyl 6-ethyl-1-phenyl-4a,5-dihydro-6H-2a,6-diazapentaleno[1,6-cd]azulene-3,4,4a,5-tetracarboxylate, tetramethyl 3-phenyl-9b-azaindeno[1,6,7-bcd]azulene-1,2,8,9-tetracarboxylate, and dimethyl [8-phenyl-1,2,3-tris(methoxycarbonyl)-8H-3a-azacyclopent[1,2-a]inden-8-yl]maleate. However, the reaction of 8-acetylamino-3-phenyl-1-azaazulene with DMAD gave dimethyl-1-phenyl-2a,5-diazabenz[cd]azulene-3,4-dicarboxylate, trimethyl 3-phenyl-8,9b-diazaindeno[1,6,7-bcd]azulene-1,2,9-tricarboxylate, dimethyl 3-phenyl-8,9b-diazaindeno[1,6,7-bcd]azulene-1,2-dicarboxylate, tetramethyl 6-acetyl-1-phenyl-4a,5-dihydro-6H-2a,6-diazapentaleno[1,6,7-cd]azulene-3,4,4a,5-tetracarboxylate. The structures of the obtained compounds were determined by inspections of their physical and spectral data, and by single-crystal X-ray analyses of some of these compounds. The reaction mechanisms of these reactions are discussed.
  • Makoto Sakakibara, Takahiro Mizumoto, Yoshihiko Watanabe, Takeshi Toru ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1794-1798
    Published: 1992
    Released: July 15, 2006
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    Novel polycyclic selenepinone compounds, benzo[b]naphtho[2,3-f]selenepin-6,11,13(12H)-trione (6) and 6,14-dimethoxybenzo[1,2-b:5,4-b′]bis[1]benzoselenepin-12,16(13H,15H)-dione (14) were synthesized from chloroquinones.
  • Takeshi Yamamura, Hiroki Arai
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1799-1806
    Published: 1992
    Released: July 15, 2006
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    The dissociation feature of nickel complexes of arenethiolates, [Ni(RS)4]2− (RSH = p-CH3C6H4SH, m-CH3C6H4SH, C6H5SH, p-ClC6H4SH, p-NO2C6H4SH) in DMSO was studied by spectrophotometric method. 1H NMR experiment on [Ni(RS)4]2− (RSH = 2,4,6-trideuteriobenzenethiol) in DMSO-d6 revealed that this system obeys the following equilibrium scheme generating the diamagnetic nickel species, [Ni(RS)3(solv)] and [Ni(RS)2(solv)2] (solv = solvent ligand). Dissociation constants Kd, Ke, and Kd′ were calculated from the NMR data.

    Intrinsic UV-vis. absorption spectra of [Ni(RS)n(solv)4−n](n−2)− (RS = C6H5S, n = 2, 3, 4) were derived from the least squares fitting analyses of the absorption change data obtained under different concentrations of RS. The absorption spectrum of [Ni(t-C4H9S)4]2− was also measured in solid state. Crystal field calculations for both [Ni(C6H5S)4]2− and [Ni(t-C4H9S)4]2− were examined. The results were compared with those of [NiX4]2− (X = Cl, Br, I), as well as the nickel exchanged aspartate transcarbamoylase. The structures of [Ni(RS)n(solv)4−n](n−2)− were discussed.
  • Takashi Fukuchi
    1992 Volume 65 Issue 7 Pages 1807-1811
    Published: 1992
    Released: July 15, 2006
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    The complexes of nitrosylruthenium(III) with vicinal-dioximato ligands, [Ru(vic-dioximato)2X(NO)] (vic-dioximato = 2,3-butanedione dioximato (Hdmo), 1,2-diphenylethanedione dioximato (Hdpo), or 1,2-cyclohexanedione dioximato (Hcho); X = Cl, Br, or I), and the complexes of carbonylruthenium(II) with Hdpo, [Ru(Hdpo)2(CO)L] (L = H2O or pyridine), were synthesized. The results of the 1H, 13C NMR, and IR spectra showed that the trans and cis isomers were present in some of the nitrosylruthenium(III) complexes.
  • Masaru Kimura, Fumiko Nakazawa, Keiichi Tsukahara
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1812-1816
    Published: 1992
    Released: July 15, 2006
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    The photo-induced reduction kinetics of iodine by monoamine-N-polycarboxylate ions, such as nitrilotriacetic acid (H3nta), iminodiacetic acid (H2ida), 2-hydroxyethyliminodiacetic acid (H2hida), as well as o-, m-, and p-isomers of N-(carboxyphenyl)iminodiacetic acid (H3cpida), were made in an aqueous solution containing iodide ions in excess over the pH range 1.6–7.6; the photo-induced reductions of iodine by triethylamine (TEA) and tris(2-hydroxyethyl)amine (TEOA) were also studied. The reactive species are a I2−• radical anion, produced in the primary photoreaction, and a fully deprotonated species of monoamine-N-polycarboxylate, TEOA, or TEA. Both hydrogen ion and complex-forming metal ions, such as copper(II) and zinc(II), were strong inhibitors for all of the reactions investigated. The role of the lone electron pair on the amine nitrogen is discussed.
  • Takayoshi Suzuki, Naoyuki Iitaka, Saeko Kurachi, Masakazu Kita, Kazuo ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1817-1824
    Published: 1992
    Released: July 15, 2006
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    Crystal structures of Pd(I) and Pt(I) dinuclear complexes, [MM′Cl2(μ-Me2Ppy)2] (MM′ = Pd2 (1), PdPt (2), and Pt2 (3)) and [Pd2Cl2(μ-Ph2Ppy)2] (4), were determined by the single crystal X-ray diffraction method. Crystal data and final R values are: 1, triclinic, , a = 10.019(2), b = 10.902(2), c = 9.062(1) Å, α = 97.75(2), β = 102.45(2), γ = 82.64(2)°, V = 952.7(3) Å3, Z = 2, and R = 0.047; 2, monoclinic, P21/n, a = 16.532(2), b = 19.205(3), c = 13.260(2) Å, β = 93.86(2)°, V = 4200(1) Å3, Z = 8, and R = 0.043; 3, monoclinic, P21/n, a = 16.515(5), b = 19.095(10), c = 13.233(4) Å, β = 93.15(3)°, V = 4167(3) Å3, Z = 8, and R = 0.047; 4, monoclinic, C2/c, a = 30.505(4), b = 17.896(2), c = 12.983(1) Å, β = 98.52(1)°, V = 7009(1) Å3, Z = 8, and R = 0.041. All of the complexes were found to be the head-to-tail isomer of a side-by-side type dinuclear structure. The metal–metal bond distances of 2.584(1) Å in 1, 2.561(1) Å in 2, 2.573(1) Å in 3, and 2.594(1) Å in 4 are relatively short compared with those in the analogous dinuclear complexes bridged by diphosphine ligands. All of the M–P, M–N, and M–Cl distances in Me2Ppy complexes become shortened in the order of the Pd2 > PdPt > Pt2 complexes.
  • Yonezo Maeda, Yosuke Noda, Hiroki Oshio, Yoshimasa Takashima
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1825-1831
    Published: 1992
    Released: July 15, 2006
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    A new spin-crossover complex [Fe(mbpN)(lut)]BPh4 (H2mbpN; N,N′-bis[(2-hydroxy-5-methylphenyl)phenylmethylene]-4-azaheptane-1,7-diamine and lut; 3,4-dimethylpyridine) is reported. The structure of this complex was determined at 293 K, and the temperature dependence of the 57Fe Mössbauer spectra and magnetic susceptibilities was examined. The complex undergoes a faster spin-state interconversion than the lifetime of the 57Fe excited state (1 × 10−7 s). More importantly, it has been found that the quadrupole splittings of the complex show the lowest value at intermediate spin-state transformations. This behavior is illustrated by a model in which the electric field gradient of the high-spin state has the opposite sign with that of the low-spin state. The monoclinic crystal of [Fe(mbpN)(lut)]BPh4 is of space group P21/a, with a = 14.664(5), b = 37.269(4), c = 10.061(5) Å, β = 90.97(3)°, Z = 4, and refinement to R = 0.079 and Rw = 0.084. The bond distances of Fe–Oav (1.912(5) Å), Fe–Nimineav (2.080(6) Å), Fe–Namine (2.141(6) Å), and Fe–Npyridine (2.145(6) Å) are close to the expected values for the high-spin species.
  • Shinji Toyota, Michinori Oki
    1992 Volume 65 Issue 7 Pages 1832-1840
    Published: 1992
    Released: July 15, 2006
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    The molecular structures of a set of intramolecular boron-amine complexes, 9-[2-(dialkylaminomethyl)phenyl]-9-borabicyclo[3.3.1]nonanes (alkyl = Me and Et) and 2-[2-(dimethylaminomethyl)phenyl]-4,4-diphenyl-1,3,2-dioxaborolane, were determined by the X-ray analyses. The boron atom has a tetrahedral geometry and the five-membered ring is puckered with the nitrogen atom out of the plane in every complex. The distances of the N–B coordination bonds, which are in the range of 1.74–1.77Å, are not always correlated to the barrier to dissociation of the N–B bonds. In order to correlate the molecular structures to the strength of the N–B coordination bonds, the tetrahedral character, which is calculated from bond angles at a boron atom, is proposed. The usefulness as well as the limitation of this parameter are discussed.
  • Satoru Ikegami, Hiroaki Okamura, Satoru Kuroda, Tsutomu Katsuki, Masar ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1841-1848
    Published: 1992
    Released: July 15, 2006
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    The synthesis of (±)-Ireland alcohol, a key intermediate for the synthesis of tirandamycin A, was achieved in a straightforward manner by using isopropyl (2R*, 3S*, 4E)-6-benzyloxy-2-hydroxy-3-methyl-4-hexenoate as a starting material, which was readily obtained by the [2,3]Wittig rearrangement of isopropyl [(E)-1-benzyloxymethyl-2-butenyloxy]acetate via its titanium enolate.
  • Yasukazu Yoshida, Etsuo Niki
    1992 Volume 65 Issue 7 Pages 1849-1854
    Published: 1992
    Released: July 15, 2006
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    The oxidations of phosphatidylcholine liposomes in aqueous dispersions induced by copper and iron have been studied aiming specifically at elucidating the action of copper ion in the chain initiation of the oxidation of liposomal membranes. Both copper(II) and iron(III) ions induced steady oxidations and the addition of t-butyl hydroperoxide enhanced the rate of oxidation. The reduction of hydroperoxides present initially in the liposomes by triphenylphosphine markedly reduced the rate of oxidation. The rate of oxidation induced by copper(II) ion was proportional to the first power of phosphatidylcholine concentration and to the half power of both copper(II) ion and t-butyl hydroperoxide concentrations, suggesting that the oxidation was initiated by the oxygen radicals formed in the decomposition of hydroperoxide by copper(II) and copper(I) ions. The anionic dipalmitoylphosphatidic acid added into the liposomes enhanced the rate of oxidation induced by metal ions, whereas the addition of cationic octadecylamine showed little effect on the rate of oxidation.
  • Kazuko Takahashi, Takayasu Nihira
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1855-1859
    Published: 1992
    Released: July 15, 2006
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    Dipyridyl-substituted heterocycles such as 2,5-di(4-pyridyl)thiophene 3, 2,5-di(4-pyridyl)furan 4, 2,5-di(4-pyridyl)thieno[3,2-b]thiophene 7, 1,4-di(4-pyridyl)benzene 6, 2,5-di(2-pyridyl)thiophene 8, and 2,5-di(3-pyridyl)thiophene 9 have been efficiently synthesized by a simple one-pot procedure through the palladium-mediated cross-coupling reaction between (trimethylstannyl)pyridines and dibromo-substituted heteroaromatics. The spectroscopic data (IR, 1H NMR, 13C NMR, UV) as well as their reduction potentials of these compounds have been determined to evaluate the utility potentials to chelating ligands for metal complexes or to synthetic precursors of viologen-type bipyridinium salts. The conjugation interaction throughout the three rings appears to be more significant in 3 and 4 than in 6. The formation of stable redical anions and dianions of 3 and 4 has been proved by cyclic voltammetry.
  • Young-seo Park, Kimihisa Yamamoto, Shinji Takeoka, Eishun Tsuchida
    1992 Volume 65 Issue 7 Pages 1860-1865
    Published: 1992
    Released: July 15, 2006
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    Electropolymerization of pyrrole on tantalum (Ta) electrodes was carried out in Britton-Robinson buffer solutions containing 0.1 M (1 M = 1 mol dm−3) potassium chloride (KCl) under galvanostatic conditions. A polypyrrole (PPy) film and a tantalum oxide (Ta2O5) layer are formed on a Ta electrode by one electrochemical oxidation process. The conditions of this simultaneous formation were investigated in respect with the current density, pyrrole concentration, pH, and total charge. Under certain conditions ([py] = 0.5 M, pH = 1.8, current density = 3.5 mA cm−2, charge 1 C), a 5.6 μm thick PPy film was efficiently formed on a homogeneous 45 nm thick Ta2O5 layer.
  • Shi-Bing Jing, Tatsuaki Yamaguchi
    1992 Volume 65 Issue 7 Pages 1866-1870
    Published: 1992
    Released: July 15, 2006
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    The long-period administration of aluminum-containing phosphate binders for the treatment of hyperphosphatemia has been shown to carry the risk of aluminum accumulation associated with many bone diseases. An iron chitosan complex prepared by chitosan and iron(II) sulfate was examined as an alternative intestinal phosphate binder. In-vitro experiments have shown that the phosphate-binding capacity of iron chitosan increases with increasing the iron content of iron chitosan, the concentration of phosphate, and the pH of the solution. The phosphate-binding capacity of iron chitosan (iron content 32 mg g−1) was over 30 mg g−1 when 10 mg of iron chitosan was admitted to 10 ml of a phosphate solution of 10 mg dl−1 (pH 7.5) at 37 °C for 6 h. This value is much higher than those of aluminum hydroxide, calcium carbonate, etc., which were practically tried before. No elution of the iron from iron chitosan could be detected under these conditions.
  • Manabu Igawa, Rie Nishiura, Noriyuki Mashiyama, Yoshimi Usuda
    1992 Volume 65 Issue 7 Pages 1871-1877
    Published: 1992
    Released: July 15, 2006
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    A hydrophobic membrane was prepared from poly(tetrafluoroethylene-co-hexafluoropropylene) by coating method to be a very thin membrane with a high water permeability. The permeation, the diffusion, and the distribution coefficients were measured by time lag method. The permeation coefficient of a salt decreased with the increase of the hydrophilicity of the salt, while hydrophilic salts are permeated readily by the coupling of water flux under a pressure gradient. The characteristic permeation properties of the hydrophobic membrane were caused by the hydrophobic hydration in the pores of the membrane and a hydrophilic ion has a low diffusion coefficient and a high distribution coefficient. The diffusion coefficient of potassium chloride increased with the increases of the temperature or the concentration, while the distribution coefficient had a minimum value at about 55 °C and decreased with the increase of the concentration. Some organics added to the source phase solution affected the hydration structure in the membrane, which changed the permeation properties of salts.
  • Chikako Nakano, Takehiko Mori, Kenichi Imaeda, Noritake Yasuoka, Yusei ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1878-1883
    Published: 1992
    Released: July 15, 2006
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    The crystal structures of tetrakis(alkylthio)tetrathiafulvalene TTCn–TTF (n = 3, 4, 6) were determined by X-ray analysis. The structures of TTCn–TTF drastically changed between n = 3 and 4. The TTC3–TTF molecule has a boat-like shape, like that of TTC1–TTF and TTC2–TTF. On the other hand, the TTC4–TTF and TTC6–TTF molecules have chair-like shapes, like that of TTC5–TTF, and columnar structures with intermolecular effective overlaps between the central π-systems. These results can explain the drastic change in the electrical properties between n = 3 and 4.
  • Takeyoshi Okajima, Hidetaka Sakurai, Noboru Oyama, Koichi Tokuda, Take ...
    1992 Volume 65 Issue 7 Pages 1884-1890
    Published: 1992
    Released: July 15, 2006
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    The piezoelectric admittance measurements of montmorillonite/poly(vinyl alcohol) (PVA) composite film-coated quartz crystal oscillators were performed in air dried over silica gel, in an atmosphere of moisture with 100% relative humidity at 25 °C and in contact with Na2SO4 aqueous solutions. By use of the electrical equivalent circuit model conventionally proposed for a piezoelectric quartz crystal, the relevant circuit parameters; resistance R, inductance L, and capacitance C were evaluated as a function of the Na2SO4 concentration (0.01–1.0 M (1 M = 1 mol dm−3)). R was almost constant above ca. 0.35 M and increased with decreasing the concentration in the lower concentrations, while L and C were almost independent of the concentration. On the basis of the electrolyte concentration dependence of R, the structural change of the clay/PVA composite film due to swelling with the electrolyte is discussed in comparison with the results for the clay film.
  • Kazuhiro Tanaka, Mikio Katsube, Ken-ichi Okamoto, Hidetoshi Kita, Osam ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1891-1897
    Published: 1992
    Released: July 15, 2006
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    The lifetime and the intensity of ortho-positronium (o-Ps), τ3 and I3, respectively, were measured for a series of polyimides prepared from 4,4′-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]diphthalic dianhydride. Average size of free space holes probed by o-Ps, υh,Ps, was evaluated from τ3 using an empirical equation. There was a clear correlation between logarithm of diffusion coefficients, , of CO2 and CH4 and υh,Ps for the polyimides. Large differences in among the polyimides having the same fractional free space, VF, were attributed to differences in υh,Ps. There was a fairly good correlation between log and (υh,PsI3)−1, suggesting that I3 is a measure of the concentration of free space holes which can accommodate o-Ps, at least for the polyimides with the similar chemical structure. Correlation between VF and υh,PsI3 was rather poor.
  • Hiroshi Yokoi, Yasuyoshi Mori, Tsuyoshi Mitani, Satoshi Kawata
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1898-1902
    Published: 1992
    Released: July 15, 2006
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    Plots of the effective magnetic moment (μeff) of the iron(III) ion against pH for aqueous iron(III) ion solutions of 1,2-ethanediol, 1,3-propanediol, glycerol, D-glucitol, D-fructose, two oligo-sugars, poly(vinyl alcohol) (PVA), and methyl cellulose at various concentration ratios of polyols or sugars to the iron(III) ion ([iron(III) ion] = 10.0 mM) at room temperature were obtained by the Gouy method. At low concentraion ratios, precipitation resulted at around neutral pH, where the concentration of polymers is expressed in terms of the monomeric residues. The pH range for precipitation became narrower as the ratio increased. However, the precipitates, once formed for the case of the former two diols, remained unchanged at any alkaline pH. During the course of the change in pH from 1 to 13, the μeff value in units of B.M. was initially ca. 6, but steeply decreased at around pH 2, and then leveled off at a constant value of ca. 3.6 in the pH range 3 to 10. It gradually rose to a value of 5–6 beyond pH 10 for the cases of glycerol, D-glucitol, and sugars. This fact, together with the ESR data obtained here, indicates that iron(III) ions exist as usual hydrated ions at pH 1–2, as some cluster like Fe(OH)3 at pH 3–10, and mostly as mononuclear ions coordinated to the alcoholic OH groups at a stronger base pH.
  • Takao Oi, Takuya Takeda, Hidetake Kakihana
    1992 Volume 65 Issue 7 Pages 1903-1909
    Published: 1992
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    Ester formations of borate ion with 1,2-propanediol, 3-amino-1,2-propanediol, and (±)-3-dimethylamino-1,2-propanediol and stabilities of the formed esters were studied by 11B NMR spectroscopy. For each of the boric acid–diol systems, esters with the 1 : 1 mole ratio of borate ion and diol and with the 1 : 2 mole ratio were formed. In each of the amino–diol–containing systems the 1 : 1 ester was in fact composed of two esters; one from a borate ion and a diol molecule and the other from a borate ion and a protonated diol. Similarly, the 1 : 2 ester consisted of two esters; one from a borate ion and two diol molecules and the other from a borate ion and two protonated diols. The stability constants of the esters formed were calculated based on the peak areas of the signals of the boron species on the 11B NMR spectra. The stability of an ester was strongly correlated with the electronegativity of the anchor moiety of the diol; a higher electronegativity in general yielded a more stable ester.
  • Junji Noro, Tatsuya Sekine
    1992 Volume 65 Issue 7 Pages 1910-1914
    Published: 1992
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    The solvent extraction of europium(III) in 0.1 mol dm−3 sodium nitrate solutions with benzoylacetone (Hbza) or benzoyltrifluoroacetone (Hbfa) in carbon tetrachloride was measured in the absence and presence of tetrabutylammonium ions (tba+). Although extraction with Hbfa occurred at lower pH than with Hbza, the extraction measured as a function of the β-diketonate ion concentration in the aqueous phase was rather similar. It was also found that extraction with Hbfa was greatly enhanced by the addition of tba+, the effect, however, was negligible with Hbza. The data were analyzed from the stand point that the neutral metal chelate, Eu(bfa)3, was extacted into the organic phase and associated with ion-pairs of the reagents, bfatba+, in this phase. It was also found that though extraction of ion-pairs of bfa tba+ occurred, that of bzatba+ was negligible. Thus, the reason for the negligible extraction of the ternary complex, Eu (bza)4 tba+, was explained in terms of the negligible extraction of the bzatba+, which might associate with Eu(bza)3 in the organic phase.
  • Tetsuhiko Yoshimura, Hiroo Toi, Shinji Inaba, Hisanobu Ogoshi
    1992 Volume 65 Issue 7 Pages 1915-1919
    Published: 1992
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    The bis(1-methylimidazole)iron(II) complexes of porphyrins substituted with one, two, or four CF3 groups at pyrrole β-positions of a porphyrin have been studied by electronic absorption and magnetic circular dichroism (MCD) spectroscopies. The splittings of Q-bands observed in the electronic spectra of the complexes may arise from asymmetrical electronic effects of the highly electron-withdrawing CF3 group on the porphyrin periphery. The ratio of absorption intensity (ε(α)/(ε(β)) decreased with an increase of the number of CF3 group, suggesting the decrease of a splitting in HOMOs. The MCD spectra of the bis(1-methylimidazole)iron(II) porphyrin complexes were markedly sensitive to the porphyrin peripheral substituents. The MCD spectra in Soret region successively changed in shape with the number of CF3 group on porphyrin periphery and consequently were apparently inverted in sign, which can be explained by the shift of maximal wavelength accompanied by a change in intensity.
  • Takaji Yasui, Tomoharu Ama, Hiroshi Kawaguchi, Ken-ichi Okamoto, Jinsa ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1920-1926
    Published: 1992
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    Four geometrical isomers for [Co(edma)(NH3)(en)]2+ (edma = ethylenediamine-N-acetate) were prepared for the first time; isomers with the facially chelated edma ligand were optically resolved. Geometrical structures were assigned on the basis of the absorption, 1H NMR, 13C NMR, and CD spectral data; the crystal structure of one of these isomers was determined by an X-ray diffraction method. The crystal is orthorhombic, space group P212121, a = 8.345(1), b = 21.054(2), c = 7.914(1) Å, V = 1390.6(3) Å3, Z = 4, and R = 0.047 for 1985 independent reflections [Fo>3σ(Fo)]. The cobalt atom is octahedrally surrounded by one ammine, the bidentate en, and the facially chelated edma ligands. The ammine ligand occupies the trans position of the secondary nitrogen atom in the edma, trans(Nc, NH3) geometry. This cation, which shows a positive CD sign at 519 nm, takes a ΛΔ configuration around the cobalt atom and an S configuration around the secondary nitrogen atom. The absolute configurations of the other optically active isomers with the facially chelated edma ligand were assigned based on the stereospecific deuteration for the methylene protons of the glycinate ring in the edma ligand in a basic D2O solution.
  • Tetsuaki Nishida, Satoru Inoue, Yoshimasa Takashima
    1992 Volume 65 Issue 7 Pages 1927-1931
    Published: 1992
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    IR-transmission spectra of 95TeO2·5Fe2O3 glass piece show a gradual decrease in the transmittance due to the crystallization initiating at the surface and spreading to the bulk. XRD, IR absorption spectra, and 57Fe-Mössbauer spectra show the formation of paratellurite (α-TeO2) and iron tellurite in the glass matrix. Johnson–Mehl–Avrami plot yields the activation energy (Ea) of 2.9 ± 0.3 eV for the crystallization when the crystallized fraction is approximated by the decreased fraction of IR-transmittance. The Ea is identical to the Te–O single bond energy (3.0 eV) obtained from the literature. Kissinger plot of DTA used for the crystallization in the bulk yields Ea of 2.3 eV. These results indicate that the crystallization proceeds in a two- or three-dimensional manner by the diffusion process both in the bulk and at the surface. Ar+-laser irradiation of 95TeO2·5Fe2O3 glass results in a decrease in the IR-transmittance, indicating the “optical memory” effect.
  • Takahiko Akiyama, Hajimu Hirofuji, Shoichiro Ozaki
    1992 Volume 65 Issue 7 Pages 1932-1938
    Published: 1992
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    A combination system of AlCl3N,N-dimethylaniline was found to cleave benzyl ethers readily to give parent alcohols in excellent yields. The system also cleaved allyl as well as methyl ethers. Numerous functional groups such as benzoyloxy, phenylthio, and olefinic double bond were not affected. Comparisons of AlCl3N,N-dimethylaniline and AlCl3–anisole were described.
  • Makoto Sugiura, Masahiko Minoda, Junji Watanabe, Takeshi Fukuda, Takea ...
    1992 Volume 65 Issue 7 Pages 1939-1943
    Published: 1992
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    This paper deals with the preparation of two series of chito-oligosaccharide derivatives, chitobiose octaalkanoates, and chitotriose undecaalkanoates, in which the amino- and hydroxyl groups were blocked with alkyl pendants of differing lengths via an ester linkage. By differential scanning calorimetry(DSC) and optical microscopic observations, these compounds were found to exhibit an enantiotropic mesophase at temperatures ranging from ca. 50 °C to ca. 200 °C. The texture of the mesophases were similar to those of the discotic columnar liquid crystals formed by the cellobiose and cellotriose equivalents. However, the amido group in the chito-derivatives seems to stabilize the mesophase to an appreciable extent, bringing about higher temperatures and a longer temperature span of the mesophase than those of the cello-equivalents.
  • Masako Sakuragi, Kunihiro Ichimura, Hirochika Sakuragi
    1992 Volume 65 Issue 7 Pages 1944-1949
    Published: 1992
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    In the presence of a proper amount of amines such as 1,4-diazabicyclo[2.2.2]octane (DABCO) and piperidine, zinc tetraphenylporphine (ZnTPP) works as a not only apparently more effective but also more photoresistant sensitizer for singlet-oxygen oxygenation of olefins than in the absence of the amines. This is ascribed to the facts that ZnTPP forms a 1 : 1 complex with DABCO, and that DABCO coodinated to ZnTPP has no ability to quench singlet oxygen, as revealed by detection of singlet oxygen phosphorescence and product distributions in oxygenation of d-limonene, 1,2-dimethylcyclohexene, and 1-phenylcyclobutene.
  • Tadamitsu Sakurai, Kazuo Utsumi, Akira Ohkita, Makoto Nakamura, Hiroya ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1950-1956
    Published: 1992
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    Quantum-yield and thermodynamic analyses of the triplet-sensitized photolysis of the title hydroxylamine (NT, 1) with 4,4′-bis(dimethylamino)benzophenone (BAB), 4-dimethylaminobenzophenone (DAB), 4,4′-dimethoxybenzophenone (DMB), and 3,3′-bis(trifluoromethyl)benzophenone (BFB) suggest that the BAB- and DAB-sensitized reactions proceed by a preferential electron-transfer pathway within a triplet-exciplex intermediate, formed between the triplet-state sensitizer and the ground-state NT, to give N-phenyl-1-naphthalenecarboxamide (2) and p-toluic acid (3). On the other hand, the energy-transfer pathway in this exciplex intermediate, eventually forming 2 and 3, as well as toluene (4), predominates for reactions sensitized with DMB and BFB having fewer electron-donating substituents than does the dimethylamino group of BAB and DAB. The finding that benzil, both excited singlet and triplet states of which lie below those of NT, brings about a sensitized photolysis to afford the same fragmentation products, provides strong evidence for the existence of a triplet-exciplex intermediate. In addition, evidence concerning the operation of an electron-transfer mechanism in our sensitized photolysis comes from an observation that the photolysis of NT sensitized with N,N,N′,N′-tetramethylbenzidine, the excited state of which is one of the most powerful one-electron reductants, gives the same product distribution as does that obtained by the BAB- and DAB-sensitized reactions.
  • Gaku Yamamoto, Takashi Nemoto, Yuji Ohashi
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1957-1966
    Published: 1992
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    The 13C dynamic NMR study revealed that 9-(2-methylbenzyl)triptycene has an energy barrier to gear rotation of 11.8 kcal mol−1 (1 cal = 4.184 J). Introduction of substituents at two of the peri-positions was expected to raise the barrier enough for atropisomerism to be realized in this system. Actually, two stable rotational isomers, ap and sc*(9S*), were separately isolated for 8-chloro- (7) and 8-bromo-1,4-dimethyl-9-(2-methylbenzyl)triptycene (8). Classical kinetic studies in toluene-d8 solutions revealed that the isomerization barriers (ΔG at 350 K) are 26.4 and 27.2 kcal mol−1 for 7 and 8, respectively. Isomerization pathways were investigated by molecular mechanics calculations, which suggested that gear rotational pathway was favored. In either compound, the sc* (9S*) rotamer was found to thermally isomerize to the ap rotamer in the solid state. X-Ray crystallographic analysis of the rotameric crystals showed that the rotamers had different crystal structures and thus the crystal would be destroyed during the isomerization.
  • Gaku Yamamoto
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1967-1975
    Published: 1992
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    In the ethylene acetal (2) of 1,2,3,4-tetrafluorotriptycene-9-carbaldehyde, equal amounts of the ap and ±sc rotamers exist in CDCl3 at equilibrium, while the equilibrium is strongly shifted to ±sc in the corresponding dimethyl and trimethylene acetals. Molecular mechanics calculations reveal the origin of this anomaly to reside in the conformation of the acetal moiety. Dynamic NMR studies show that the ap → ±sc barriers are too low for atropisomerism to be realized in these compounds (ΔG ca. 21–22 kcal mol−1 (1 calth = 4.184 J)). However, taking advantage of the unusual equilibrium behavior, the two rotamers of 2 are separately isolated as crystals by selective crystallization of one rotamer from a solution of the equilibrated rotamer mixture.
  • Kenji Uneyama, Shunsuke Watanabe, Yukio Tokunaga, Kouichi Kitagawa, Ya ...
    1992 Volume 65 Issue 7 Pages 1976-1981
    Published: 1992
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    Electrooxidation of perfluoroalkanoic acids RfCO2H (Rf = CF3, C3F7, C7F15 together with CHF2, CH2F) in the presence of electron-deficient olefins (methyl acrylate, methyl methacrylate, acrylamide, and acrylonitrile) provided perfluoroalkylated products. The electrolysis was conducted in MeCN–H2O (7 : 1) using platinum electrodes in an undivided cell. Dimerization of methyl acrylate accompanying perfluoroalkylation, occurs in 40–50% yield under 20 mA cm−2 current density. 1,2-Addition of trifluoromethyl or difluoromethyl radicals to carbon-carbon double bond predominates in acrylamide under the high current density (100–200 mA cm−2). On the other hand, 1,2-addition of trifluoromethyl and acetamido groups and 1,2-addition of trifluoromethyl and hydroxyl groups occur in the low current density ( < 5 mA cm−2) electrolysis of methyl methacrylate.
  • Shuji Emori, Chiemi Shima
    1992 Volume 65 Issue 7 Pages 1982-1984
    Published: 1992
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    Various cobalt(II) and nickel(II) 3-substituted benzoate adducts with quinoline, 4-methylquinoline, and quinoxaline were prepared. They were then characterized by means of magnetic susceptibility and IR spectroscopy. The variation in their magnetic moments is discussed in terms of the basicities of the benzoate ligands as well as the coordinate-bond lengths between the benzoate oxygen and metal atoms. For the nickel(II) compounds, the formation of weak nickel(II)–nickel(II) bonding is suggested.
  • Atsushi Takenaka, Itaru Motooka, Hiroyuki Nariai
    1992 Volume 65 Issue 7 Pages 1985-1987
    Published: 1992
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    Silver amidotriphosphate Ag4P3O9NH2, was heated at a rate of 5 K min−1 in a stream of dry air, humid air, or dry HCl. When heated to 245 °C in a stream of dry air, Ag4P3O9NH2 was decomposed mainly to oligophosphates with some phosphorus-nitrogen bonds. Condensation of Ag4P3O9NH2 by the action of HCl took place even at room temperature.
  • Masaaki Ohba, Michito Shiozuka, Naohide Matsumoto, Hisashi Okawa
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1988-1989
    Published: 1992
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    Oxamido- and oxamato-bridged binuclear nickel(II)–copper(II) complexes [CuL1Ni(Me6[14]aneN4)](ClO4)2·H2O (1), [CuL2Ni(Me6[14]aneN4)]ClO4 (2), and [CuL3Ni(Me6[14]aneN4)]ClO4 (3) have been synthesized and characterized, where Me6[14]aneN4 = rac-(5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, H2L1 = N,N′-bis(2-pyridylmethyl)oxamide, H3L2 = N-methyl-N′-(4-methyl-6-oxo-3-azahept-4-enyl)oxamide, H3L3 = N-(4-methyl-6-oxo-3-azahept-4-enyl)oxamic acid. The cryomagnetic susceptibilities (4.2–300 K) were well reproduced by the equation derived from H = −2JSNi·SCu (SNi = 1, SCu = 1⁄2) with the J values −78.2 cm−1, −64.5 cm−1, and −72.8 cm−1 for (1), (2), and (3), respectively.
  • Jianzhuang Jiang, Ken-ichi Machida, Gin-ya Adachi
    1992 Volume 65 Issue 7 Pages 1990-1992
    Published: 1992
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    A reaction of tris(acetylacetonato) cerium(III), [Ce(acac)3], with tetrapyridylporphyrinato dilithium, Li2tpyp, produces a water-soluble sandwich complex bis(tetrapyridylporphyrinato) cerium(IV), [Ce(tpyp)2], in appreciable yield, which is followed by the same water-soluble sandwich complex bis(tetramethylpyridylporphyrinato) cerium(IV), [Ce(tmpyp)2], formed by methylation of the tpyp ligand in [Ce(tpyp)2].
  • Choichiro Shimasaki, Hiroaki Nakayama, Akiko Iwaki, Eiichi Tsukurimich ...
    1992 Volume 65 Issue 7 Pages 1993-1995
    Published: 1992
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    Eleven 1,3,5-triazine derivatives were investigated by the use of a thermal-analysis techniques. These compounds showed a remarkable difference in pyrolytic behavior and decomposed thermally by a cleavage of the triazine ring and the liberation of water, isocyanic acid, and carbondioxide. The pyrolysis products were separated and identified by a gas chromatograph coupled to a mass spectrometer. All of the obtained information led to the proposal of a thermal degradation mechanism for the triazine derivatives, which is presented here. The main pyrolysis and fragmentation by electron impact mechanisms were classified into four categories, respectively.
  • Mitsuko Kikuchi
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 1996-1998
    Published: 1992
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    The molecular structures of “isobishydropulegone” and “Harries–Roeder ketol,” isomers of “bishydropulegone,” which are dimeric reduction products of pulegone, were determined as being (1S, 3aR, 4R, 6′R, 7′aS)-7′a-hydroxy-2′,2′,3′,3′,4,6′-hexamethylspiro[cyclohexane-1,1′-octahydroinden]-2-one and (1R, 3′aS, 4R, 6′R, 7′aS)-7′a-hydroxy-2′,2′,3′,3′,4,6′-hexamethylspiro[cyclohexane-1,1′-octahydroinden]-2-one respectively by the analysis of the two-dimentional NMR spectra.
  • Masakazu Nishida, Yoshio Hayakawa, Masaki Matsui, Katsuyoshi Shibata, ...
    1992 Volume 65 Issue 7 Pages 1999-2000
    Published: 1992
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    The reaction of (Z)- and (E)-6,6,6-trifluoro-4-trifluoromethyl-4-hexen-3-ones (1) with diazomethane afforded the corresponding cis- and trans-pyrazolines (2), respectively. Photochemical and thermal decompositions of the r-3, t-4-bis(trifluoromethyl)pyrazoline gave selectively r-1, t-2-bis(trifluoromethyl)-1-propionylcyclopropane (3) and 3,4-bis(trifluoromethyl)-2-ethyl-4,5-dihydrofuran (4). On the other hand, those transformations of the r-3,c-4-isomer of the pyrazoline gave a mixture of the r-1,c-2-isomer of 3, 4, and 4,5-bis(trifluoromethyl)-5-hexen-3-one (5).
  • Seiji Takeuchi, Norikazu Miyoshi, Kenji Hirata, Haruyoshi Hayashida, Y ...
    Type: Article
    Subject area: AI
    1992 Volume 65 Issue 7 Pages 2001-2003
    Published: 1992
    Released: July 15, 2006
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    Samarium (Z)-1,2-diphenylethen-1,2-diolate, which is considered to be an intermediate of a SmI2-mediated reduction of benzil, was protonated enantioselectively by quinidine to afford (R)-benzoin in 91%ee. It was found that quenching the unreacted enediolate with oxygen was crucial to obtain high enantioselectivity. The configuration of the samarium enediolate was confirmed by isolating (Z)-O,O′-diacetyl-1,2-diphenylethen-1,2-diol.
  • Yasushi Miyamoto, Mitsuji Yamashita, Tatsuo Oshikawa
    1992 Volume 65 Issue 7 Pages 2004-2006
    Published: 1992
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    Reactions of 2-phospholene 1-oxides with N-bromoacetamide in aqueous organic solvent produced 2-bromo-3-hydroxyphospholane 1-oxides, which reacted with sodium salts of dialkyl phosphonates to afford novel 2-phosphinoylphospholane 1-oxide derivatives. A 4-phosphin-oyl-2-phospholene derivative was also prepared.
  • Masaki Yamada, Yoshio Nakamura, Tadashi Hasegawa, Akinobu Itoh, Shigey ...
    1992 Volume 65 Issue 7 Pages 2007-2009
    Published: 1992
    Released: July 15, 2006
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    Some of aromatic hydrogens of 1,10-phenanthroline and its derivative, 1,10-propano-bridged 1,10-phenanthroline-2,9(1H,10H)-dione, were oxidatively substituted by chlorine atoms with excess amount of phosphorus pentachloride in phosphoryl chloride to give the polychlorinated products.
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