bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation and Reaction of Carbonyl Ylides. 1,3-Dipolar Cycloaddition of 2-Benzopyrylium-4-olates with Carbonyl Compounds
Authors: Ibata Toshikazu , Toyoda Jiro
Published: July 2006

Cyclic orthoester type 1,3-dipolar cycloadducts of 1-methoxy-2-benzopyrylium-4-olate with carbonyl compounds were obtained in high yields in the copper(II) acetylacetonate-catalyzed decomposition of o-methoxycarbonyl-α-diazoacetophenone in the presence of carbonyl compounds such as substituted benzaldehydes, acetaldehyde, propionaldehyde, isobutyraldehyde, pivalaldehyde, acetone, methyl ethyl ketone, methyl isopropyl ketone, 1,3-dichloroacetone, substituted acetophenones, benzoyl cyanides, cyclopentanone, cyclohexanone, 1-indanone, 9-fluorenone, anthrone, and anthraquinone. However, methyl t-butyl ketone, benzophenone, and xthanthone gave no adduct. Aldehydes and asymmetric ketones gave endo- and exo-adducts. The regiochemistry and stereochemistry of the adducts of aldehydes were determined on the basis of their coupling constants of methine protons. The reactions of p-methoxyphenyl o-diazoacetylbenzoate also gave similar 1,3-dipolar adducts. When carbonyl compounds of medium reactivity were used as a substrate, 2 : 1-adduct was obtained together with the 1 : 1-adduct. The formation of the 2 : 1-adduct was attributed to the competitive reaction of the corrsponding benzopyrylium-4-olate intermediate toward the carbonyl compounds and 1 : 1-adduct. The regiospecificity of the 1 : 1-cycloaddition was explained according to the frontier orbitals calculated by STO-3G method.
New Quassinoid Glucosides, Picrasinoside-A, -B, -C, -D, -E, -F, and -G and New Hemiacetals, Picrasinol-A and -B, from the Stem Bark of Picrasma ailanthoides PLANCHON
Authors: Okano Masayoshi , Fujita Tomoyuki , Fukamiya Narihiko , Aratani Takaaki
Published: July 2006

New quassinoid glucosides, picrasinoside-A, -B, -C, -D, -E, -F, and -G and new quassinoid hemiacetals, picrasinol-A and -B, were isolated from the stem bark of Picrasma ailanthoides PLANCHON, and their structures were established by spectral analyses and chemical transformations.
Liquid Crystal Materials with Sulfur Atoms Incorporated in the Principal Structure. IV. New Liquid Crystal Compounds; 2-(p-Substituted phenyl)-5-alkyl-1,3-oxathianes
Authors: Haramoto Yuichiro , Kamogawa Hiroyoshi
Published: July 2006

2-(p-Substituted phenyl)-5-alkyl-1,3-oxathianes, new liquid crystal compounds, were synthesized by the acetalformation reaction of the corresponding aldehydes and 2-alkyl-3-mercapto-1-propanols. The mesomorphic behaviors of these 1,3-oxathiane compounds were compared with those of the corresponding 1,3-dithianes and 1,3-dioxanes. Some of 2-(p-cyanophenyl)-5-alkyl-1,3-oxathianes exhibit monotropic nematic liquid crystal phase at room temperature, whereas 2-(p-alkoxyphenyl)-5-alkyl-1,3-oxathianes tend hardly to exhibit liquid-crystal phase. These mesomorphic characters seem to originate in the molecular width and bending at the 1,3-oxathiane ring.
Determination of the Acid Strength Distribution of Manganese Dioxide by the Modified Indicator Method
Authors: Sugiyama Kazuo , Nakano Yasushi , Miura Hiroshi , Matsuda Tsuneo
Published: July 2006

A new procedure for determining the distribution of acid and base centers of dark colored solids by the indicator method has been proposed. By this method weak acidic sites were found to be present on a manganese dioxide surface.
The Crystal Structures of a Dicopper(II) Complex Containing Two N4-Macrocyclic Rings Connected with an Ethylene Chain
Authors: Mikuriya Masahiro , Hamada Kosuke , Kida Sigeo , Murase Ichiro
Published: July 2006

The crystal structure of diaqua {7,7′ethylenebis[2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]-heptadeca-1 (17),2,11,13,15-pentaene]}dicopper(II) perchlorate dihydrate was determined by a single-crystal X-ray diffraction method. The complex assumes an extended conformation with the intramolecular Cu···Cu separation 7.081(2) or 6.985(2)Å.
NAD(P)+–NAD(P)H Model. 54. Free Radical Mechanism for the Reductive Debromination of vic-Dibromides to Alkenes
Authors: Yasui Shinro , Nakamura Kaoru , Ohno Atsuyoshi
Published: July 2006

vic-Dibromides undergo reductive debromination with a model of NAD(P)H, N-benzyl-1,4-dihydronicotinamide, to afford the corresponding alkenes quantitatively. Stereochemistry of the reduction suggests that the reaction involves a free radical intermediacy.
Measurement of Ultralow Interfacial Tension in the Vicinity of Critical Solution Temperature
Authors: Aratono Makoto , Motomura Kinsi
Published: July 2006

A new apparatus adopting the sessile drop technique has been designed to measure the ultralow interfacial tension between two liquids of a binary mixture. The equilibrium interfacial tension of the mixture of isobutyric acid and water has been determined near its upper critical solution temperature up to the value of 0.02 μN m−1.
Crystal and Molecular Structure of a Triply-thiolate-bridged Binudear Cobalt(III) Complex, [Co2{SCH(CH2CH2NH2)2}3](ClO4)3·H2O
Authors: Mikuriya Masahiro , Kida Sigeo , Ueno Shigehiro , Murase Ichiro
Published: July 2006

The crystal structure of tris[μ-(1,5-diamino-3-pentanethiolato)-N,N′, μ-S]-dicobalt(III) perchlorate monohydrate was determined by the single-crystal X-ray diffraction method. The binuclear complex has a novel type of binuclear structure in which the two cobalt atoms are bridged by three thiolate sulfur atoms forming a face-shared bioctahedron.
Abnormal Methyl Radicals on Alumina Surfaces
Authors: Barnes John David , Trivedi Mahendra Aruind , Oduwole Duro Abimbola , Wiseall Barrie
Published: July 2006

The ESR spectrum of abnormal methyl radicals on alumina surfaces is found to be symmetrical at low surface coverages. Possible mechanisms for the formation of these radicals are presented.
Interaction between 1,1′-Biacenaphthene-2,2′-diyl and Dibromomethane. Decay Kinetics in Mixed Solvents
Authors: Kobashi Harumichi , Masamoto Hiroshi
Published: July 2006

Interaction of the triplet biradical, 1,1′-biacenaphthene-2,2′-diyl (BR) with dibromomethane has been examined by means of transient absorption measurements and kinetic analysis. The absorption spectrum of BR in CH2Br2 shows a red shift compared with those in other solvents with various polarities. The spectral result indicates that the red shift is not due to effect of solvent polarity but due to existence of weak electronic interaction acting directly between BR and CH2Br2. The nonlinear dependence of decay rates of BR upon [CH2Br2] is interpreted in terms of a simple kinetic model of solvation based on solvent replacement between cage and bulk.
Electric and Magnetic Properties of a Neutral Radical, 2-Cyano-10-methyl-5 -phenazinyl
Authors: Awaga Kunio , Sugano Tadashi , Kinoshita Minoru
Published: July 2006

The temperature dependence of electric conductivity, static magnetic susceptibility and ESR absorption, and electronic absorption spectra at room temperature have been measured on an organic neutral radical, 2-cyano-10-methyl-5-phenazinyl (NMPN). NMPN is found to be more conductive than the neutral radicals studied previously. The room temperature conductivity of powder NMPN is of the order of 10−7 Ω−1 cm−1 and the activation energy is 0.36 eV. The absorption spectra and the magnetic susceptibility measurements indicate that the NMPN molecules form pairing array with considerably large interpair interaction in the solid state. The absence of the triplet fine structure in the ESR spectrum also suggests the existence of the interpair interaction. From these, the magnetic behavior of NMPN is interpreted in terms of the alternating antiferromagnetic Heisenberg model with temperature dependent alternation.
Conformation and Coordination Behavior of Zinc(II) Complex with Cyclo(l-methionyl-l-histidyl)
Authors: Kojima Yoshitane , Hirotsu Ken , Yamashita Tetsushi , Miwa Toshio
Published: July 2006

The crystal structure of a zinc(II) complex with cyclo(l-methionyl-l-histidyl) shows that all four ligands coordinated tetrahedrally to a Zn2+ ion have a folded conformation, with the imidazole ring facing the piperazine ring in each ligand. The calculation from α-β coupling constant data (obtained by 1H NMR measurement) of the histidyl residue of cyclo(l-methionyl-l-histidyl) linked to a Zn2+ ion shows that the ratio of a folded conformation to an unfolded one is 61:39 in D2O.
The Facile Synthesis of Dihydrofurans by the Oxidation of Olefins with Tris(2,4-pentanedionato)manganese(III)
Authors: Nishino Hiroshi
Published: July 2006

Eleven olefins were oxidized with tris(2,4-pentanedionato)manganese(III) at the reflux temperature to give the corresponding 3-acetyl-2-methyl-4,5-dihydrofurans in good yields. The oxidation of 9-benzylidene-9,10-dihydroanthracene under the same reaction conditions did not produce the corresponding dihydrofuran, but 9-[α-(1-acetyl-2-hydroxy-1-propenyl)benzylidene]-9,10-dihydroanthracene. When 1,1-diphenylethene was oxidized at room temperature, 3-acetyl-2-hydroperoxy-2-methyl-5,5-diphenyltetrahydrofuran was obtained in a high yield. The effects of the solvent and the additives on the yield of dihydrofuran, the comparable reactivities of other (2,4-pentanedionato)metal complexes, such as Co(III), Cr(III), Fe(III), and Cu(II), and the reaction mechanism are discussed.
ESR and ENDOR Studies of Cation Radicals Derived from Benzodipyran Compounds. Structure and Dynamic Behavior of Heterocyclic Ring in Tocopherol (Vitamin E)
Authors: Mukai Kazuo , Uemoto Yuichi , Ishizu Kazuhiko
Published: July 2006

ESR and ENDOR spectra of cation radicals of benzodipyran compounds were measured in CH2Cl2, and the proton hyperfine coupling constants were correctly determined for each radical. From detailed analysis of the temperature dependence of hyperfine coupling of β- and γ-methylene protons in the heterocyclic ring, the equilibrium conformation of the β-methylene group and activation energy for the conformational interconversion have been determined. The structure of the heterocyclic ring was compared with those of α-tocopherol (vitamin E) model previously obtained by X-ray analysis. The result suggests that the solution and crystal conformations of the heterocyclic ring are distinctly different.
A Convenient Route to 2-Lithio-1,3-butadiene from Chloroprene via 2-Stannyl-1,3-butadiene
Authors: Wada Eiji , Kanemasa Shuji , Fujiwara Isamu , Tsuge Otohiko
Published: July 2006

A convenient route to 2-lithio-1,3-butadiene from chloroprene via a 2-stannyl-1,3-butadiene is presented, and the regioselecdve additions to a variety of carbonyl groups are demonstrated.
Restricted Rotation Involving the Tetrahedral Carbon. LVII. Stereodynamics of 9-(2-Alkylphenoxy)-1,4-dimethyltriptycenes
Authors: Yamamoto Gaku , Oki Michinori
Published: July 2006

1,4-Dimethyl-9-phenoxytriptycene and its derivatives carrying a methyl, isopropyl, or t-butyl group in the o-position of the phenoxyl moiety were synthesized and their dynamic NMR behavior was studied. These molecules are considered to constitute a bevel gear system with a two-toothed and a three-toothed wheels and the dynamic NMR behavior is best explained in terms of gear rotation. The o-isopropyl derivative, for example, shows the energy barriers of 17.2 and 10.8 kcal mol−1 for the ap\ightleftharpoons±sc and +sc\ightleftharpoons−sc gearing processes, respectively. The population of the ±sc rotamer increases with the bulkiness of the o-alkyl group: The steric congestion among the o-alkyl group, the oxygen atom, and the peri-methyl group is severer in ap than in ±sc. Results of molecular mechanics calculations on these molecules are discussed.
Hydrogenation of Pyrene and Catalytic Interconversion of Hydropyrenes
Authors: Minabe Masahiro , Nakada Katsuko
Published: July 2006

Reexamination on the hydrogenation of pyrene (1) with Raney nickel catalyst under atmospheric pressure afforded a mixture of 4,5-di- (2), 4,5,9,10-tetra- (3), 1,2,3,6,7,8-hexa- (4), and 1,2,3,3a,4,5-hexahydropyrene (5). The relative amount of each product at the initial reaction stage was determined by time–yield relation of the products. The formation sequence of the products is discussed with reference to the hydrogenations of 2–5: 4 may be formed independent of 2, and 2 is converted to 3. Hydropyrene 5 may be produced from 1 mainly through the same σ-adsorbed species which also leads to 2. The hydrogenation of 1 with palladium and platinum catalysts gave similar results as with nickel. With nickel and palladium catalysts the hydrogenation of 1 was faster than that of 4H-cyclopenta[def]phenanthrene (9). However, with platinum the hydrogenation of 1 was slower than that of 9. Catalytic interconversion of 2–5 was examined at 240 °C under an argon pressure of 90 kg cm−2. Hydroarene 2 was easily dehydrogenated, and 3 and 5 were interconverted to a fair extent. Therefore, 2, 3, and 5 may be good hydrogen donor solvents for coal liquefaction.
Rotational Isomerism in Fluorene Derivatives. IX. Restricted Rotation about the C(9)–C(9′) Bonds in 9(or 9′)-Substituted2-Methyl-9,9′-bifluorenyls
Authors: Kajigaeshi Shoji , Nishida Akiko , Fujisaki Shizuo
Published: July 2006

Several 9(or 9′)-substituted 2-methyl-9,9′-bifluorenyls were prepared and the restricted rotation about the Csp3–Csp3 bonds in these compounds were investigated by DNMR. In these cases, nonequivalent gauche conformers were observed at low temperatures. Barriers (ΔG\eweq) for the forward and backward interconversions were slightly increased in agreement with the bulkiness of the 9(or 9′)-substitutents.
α,β-Epoxy Sulfoxides as Useful Intermediates in Organic Synthesis. I. A Novel Synthesis of Dialkyl Ketones and a Synthesis of Aldehydes from Ketones by One Carbon Elongation
Authors: Satoh Tsuyoshi , Kaneko Youhei , Izawa Takao , Sakata Kiichi , Yamakawa Koji
Published: July 2006

Treatment of α,β-epoxy sulfoxides, prepared from 1-chloroalkyl phenyl sulfoxides with ketones or aldehydes, with sodium benzeneselenolate gives dialkyl ketones or aldehydes in good yields under mild conditions. The mechanism of this reaction and an application of this process to a formal total synthesis of dihydrojasmone are described.
Vibrational Analysis of Tangled Spectra. I. The Crystal Phase T←S Spectra of Acetophenone
Authors: Nakashima Kenichi , Koyanagi Motohiko
Published: July 2006

The T1,2←S0 phorescence excitation spectrum of acetophenone has been observed in a crystal at 4.2 K. The observed tangled vibronic structure is a manifestation that two states of different orbital types, 3ππ* and 3nπ*, lie close to each other. For the first time, the spectrum has been vibrationally analyzed in terms of the crude adiabatic Born-Oppenheimer vibronic states. The calculation is advanced via the following steps: (1) to assume appropriate zero-order vibronic level functions of both electronic excited states in the energy region 0–1000 cm−1 above the T1 phosphorescent origin level, (2) to take into account two different perturbations of vibronic and environmental interactions, (3) to establish a secular equation with two adjustable parameters for the evaluation of the off-diagonal matrix elements, (4) to diagonalize the equation after allocating appropriate values to the parameters, (5) to simulate the T←S spectrum, (6) to compare the simulation spectrum with the observed, (7) to revise several diagonal elements and the parameters if the comparison is not satisfied, and (8) to proceed with steps (1)–(7) until the simulation spectra accord with the observed. The results establish that the lowest excited triplet state of acetophenone in the crystal is ππ*, and that the next one is nπ* whose zero-order vibrationless level is postulated to lie at ≈400 cm−1 higher than T10(0).
Adsorption of Phenol on Surface-modified Carbon Black from Its Aqueous Solution. II. Influence of Surface-chemical Structure of Carbon on Adsorption of Phenol
Authors: Asakawa Takeo , Ogino Keizo , Yamabe Kiyoshi
Published: July 2006

Samples of electronic conductive carbon black (Lion Akzo Co.) were treated with nitric acid, hydrogen peroxide, dried air, or hydrogen gas. These samples had almost the same specific surface areas and pore volumes, except for the one treated with nitric acid. Phenol gas adsorption and aqueous-phase adsorption were carried out in order to study the adsorption mechanism on these treated samples. During aqueous-phase adsorption, the amount of phenol adsorbed increased with a decrease in the number of surface oxygen compounds on the carbon sample. During gas adsorption, the amount of phenol adsorbed decreased with a decrease in the number of oxygen compounds on the carbon surface. The residual amount of phenol also decreased. In the case of gas adsorption, interactions occur not only between the hydrophobic sites on the carbon and the hydrophobic groups of phenol, but also between the surface functional groups on the carbon and the hydrophilic groups of phenol. In the case of aqueous-phase adsorption, competitive adsorption of phenol with water molecules occurs. Water molecules adsorb, selectively, the surface functional groups on the carbon. Thus, the phenol adsorption due to the hydrophobic interaction on the carbon interferes with this selective adsorption.
Photoinduced Reduction of Methylviologen by Ascorbate Using Chlorophyllin in Liposome System
Authors: Hidaka Seiji , Matsumoto Eizo , Toda Fujio
Published: July 2006

Photoindeced electron transport across bilayer lipid membrane was studied, using chlorophyllin (Chln), a water-soluble derivative of chlorophyll. Photoreduction of methylviologen (MV2+) by ascorbate was observed only in the liposome system containing ascorbate in the internal aqueous phase and MV2+ in the external aqueous phase. This suggests asymmetry of bilayer lipid membrane. This reaction rate was not affected by the addition of carbonyl cyanide m-chlorophenylhydrazone in the system buffered by tris(hydroxymethyl)aminomethane (Tris), but strongly affected by N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid. In the system buffered by Tris, a proton carrier is not Chin having carboxyl groups but Tris possessing primary amine group. Replacement of the central Mg of Chin with Zn gives a higher rate of MV2+ photoreduction, but when Cu was used in place of Zn, photoreduction was not observed. The central metal may affect the redox potential and the life time of excited Chln.
The Thermal Addition Reactions of Cycloheptatriene with Aromatic p-Quinones
Authors: Mori Akira , Mametsuka Hiroaki , Takeshita Hitoshi
Published: July 2006

Thermal addition reactions of cycloheptatriene with several aromatic p-quinones gave the Diels-Alder adducts as minor products; the most characteristic feature was the formation of the vic-ditropylation products. The mechanism of their formation was clarified to be a sequential ene-reaction and dehydrogenation by means of chemical conversion from the isolated intermediates. Several new other additions, e.g., successive Diels-Alder reactions, were also noted.
The Pulse-photoconductivity of Poly(N-vinylbenzocarbazole)s
Authors: Itaya Akira , Okamoto Ken-ichi , Kusabayashi Shigekazu
Published: July 2006

The hole-drift mobility and the carrier-photogeneration efficiency of holes in poly(5-vinylbenzo[b]carbazole)(P5VBCz) and poly(7-vinylbenzo[c]carbazole)(P7VBCz) films were investigated by means of the time-offlight method and compared with those in poly (N-vinylcarbazole)(PVCz) films. The mobilities of these polymers were nearly equal to each other and smaller than that of PVCz by a factor of ca. 1/3. The electric field and temperature dependence of the mobilities fit Gill’s empirical equation. The small mobilities of both P5VBCz and P7VBCz were apparently attributable to the small values of the pre-exponential factor, μ0. The carrier-photogeneration efficiencies, φ, of these polymers were larger than that of PVCz by a factor of ca. 10. The field dependence of φ of these polymers for the excitation of the 1Ba absorption band was in good agreement with the Onsager theory of geminate recombination. These results indicate that the introduction of bulky and unsymmetric benzocarbazolyl chromophores instead of carbazolyl ones as a pendant group of vinyl polymers is a good modification from the point of view of the carrier-photogeneration, but not from the viewpoint of the carrier transport.
Rearrangement Approaches to Cyclic Skeletons. I. Photochemical Rearrangement Approaches to (±)-Sesquicarene and (±)-Sirenin, [3–6] Fused-Ring Sesquiterpenes
Authors: Uyehara Tadao , Yamada Jun-ichi , Ogata Koichi , Kato Tadahiro
Published: July 2006

The 4-alkyl, 4-alkenyl, and 4-aryl derivatives of bicyclo[3.2.2]nona-3,6-dien-2-one (9) were prepared from 9 itself by ultrasound-promoted Barbier reaction followed by PCC oxidation. Photochemical transformation of the 4-(4-methyl-3-pentenyl) derivative of 9, namely 13, in THF–water gave endo-7-[exo-7-(4-methyl-3-pentenyl)bicyclo[4.1.0]hept-2-ene]acetic acid (14). Acid 14 was converted into endo-7-methyl-exo-7-(4-methyl-3-pentenyl)bicylo[4.1.0]heptan-2-one (4), a key intermediate of (±)-sesquicarene and (±)sirenin total syntheses. Furthermore, a highly stereospecific total synthesis of (±)-sesquicarene was acomplished by the photochemical transformation of the 1-methyl derivative of 13 prepared from 2-methyltropone (21).
Dopant Structure in FeCl3-doped Polyacetylene Studied by X-Ray Absorption Spectroscopy and X-Ray Photoelectron Spectroscopy
Authors: Asakura Kiyotaka , Ikemoto Isao , Kuroda Haruo , Kobayashi Takaaki , Shirakawa Hideki
Published: July 2006

The dopant structure in FeCl3-doped polyacetylene was studied from the analysis of Fe K-edge EXAFS and XANES, measured by use of synchroton radiation. It is concluded that Fe atom is surrounded by four Cl atoms with Fe–Cl distance of 2.19–2.20 Å, and the dopant exists in the state of [FeCl4]−. The following mechanism is proposed for the doping process:

(CH)x+2yxFeCl3→[CH(Fe(Cl4−)y]x+yxFeCl2

It is also shown that the chlorination of polyacetylene occurs significantly on performing a “heavy doping.”
Regioselectivity of the Coupling of Phenoxyallyllithium with Allylic Electrophiles
Authors: Butsugan Yasuo , Goto Tomokazu , Araki Shuki
Published: July 2006

The regioselectivity of the coupling of phenoxyallyllithium with allylic electrophiles was investigated. The allylation pattern corresponded with the hardness of the leaving group and the highest α-selectivity was observed in the reaction with allylic phosphate.
N-Nitroso Compounds. IV. Reaction of N-Nitrosourea with Thiol. A New Synthesis of Thiocarbamic S-Esters
Authors: Yoshida Kitaro , Isobe Masayoshi , Yano Kazuyuki , Nagamatsu Kazuo
Published: July 2006

Thirteen thiocarbamic S-esters have been synthesized in good yield by the reaction of thiol with substituted N-methyl-N-nitrosourea in anhydrous acetonitrile.
Synthesis of Macrocarbocycles Utilizing Intramolecular 1,3-Dipolar Cycloaddition of Nitrile Oxides. Synthesis of (±)-Muscone
Authors: Asaoka Morio , Abe Masayoshi , Takei Hisashi
Published: July 2006

Intramolecular 1,3-dipolar cycloaddition of nitrile oxides generated from ω-nitro-1-alkenes gave isoxazoline-fused macrocarbocycles (ring size 12, 14, 15, and 16) in fair to good yields. The 15-membered derivative was converted into (±)-muscone.
The Reactions of Silicon Phosphate with Alkaline Earth Metal Oxides at High Temperatures
Authors: Narita Eiichi , Sango Kazuhiro , Naito Hiroyuki
Published: July 2006

The reactions of Si3(PO4)4 with CaO and MgO at high temperatures up to 1150 °C yielded silicon phosphate glass, Me3(PO4)2, Me2P2O7, and α-cristobalite, depending on the temperature, the heating time, and the MeO/Si3(PO4)4 molar ratio (Me: Ca and Mg). These reactions were found to proceed by means of the one-way diffusion of alkaline earth metal oxides into the Si3(PO4)4 phase.
Reaction of Olefins with Malonamide in the Presence of Manganese(III) Acetate. Formation of α,β-Unsaturated γ-Lactones and γ-Lactams
Authors: Nishino Hiroshi
Published: July 2006

The reaction of olefins with malonamide in the presence of manganese(III) acetate gave 2-buten-4-olides and/or 1H-pyrrol-2(5H)-ones in one-step, short reaction time, and moderate yields. The product distribution can be accounted for in terms of the stabilization of the intermediate carbocation in the oxidation process. The synthetic application and limitation, and the oxidation mechanism for the formations of α,β-unsaturated γ-lactones and γ-lactams are discussed.
Synthesis and Molecular Structure of the 2:1-Cycloadduct of 1-Methoxy-2-benzopyrylium-4-olate with Acenaphthylene
Authors: Toyoda Jiro , Ibata Toshikazu , Tamura Hatsue , Ogawa Kazuhide , Nishino Tsuyoshi , Takebayashi Matsuji
Published: July 2006

The Cu(acac)2-catalyzed decomposition of o-methoxycarbonyl-α-diazoacetophenone in the presence of acenaphthylene gave a 2:1-cycloadduct of the corresponding carbonyl ylide, 1-methoxy-2-benzopyrylium-4-olate, with acenaphthylene along with exo- and endo-1:1-adducts. The molecular structure of the 2:1-adduct was determined by means of X-ray analysis. The colorless crystals of the adduct are triclinic with the space group P\bar1,and with the unit-cell dimensions of a=12.104(2), b=12.477(3), c=9.112(2)Å, α=102.98(3), β=110.16(2), γ=70.65(1)°, and Z=2. The structure was determined by direct methods and refined by block-diagonal least-squares methods. All hydrogen atoms were revealed by a difference-Fourier synthesis, and further least-squares refinement gave the final R value of 0.057 for 3681 observed reflections. The configurations of methine protons obtained by X-ray methods are compatible with the NMR coupling pattern of the adduct.
Studies of the Formation of Complexes of Np(V) with Inorganic Ligands by Means of Solvent Extraction with 2-Thenoyltrifluoroacetone and 1,10-Phenanthroline. II. Fluoro, Sulfato, and Phosphato Complexes
Authors: Inoue Yasushi , Tochiyama Osamu
Published: July 2006

The formation constants of the complexes of Np(V) with fluoride, sulfate, and phosphate have been determined in 1 mol dm−3 NaClO4 at 25 °C by means of the solvent-extraction method using 2-thenoyltrifluoroacetone and 1,10-phenanthroline. Extractions at various pH values revealed that H2PO4− and HPO42− participate in the complex formation of Np(V).
The Bound Ligand Effect in the Complexation Kinetics of Some Anionogallium(III) Complexes
Authors: Yamada Shinkichi , Tanaka Motoharu
Published: July 2006

The formation rate of some anionogallium(III) complexes (GaA) with 4,5-dihydroxy-1,3-benzenedisulfonate (H2L2−) in the presence of thiocyanate ion has been studied spectrophotometrically by a stopped-flow technique. The rate law is expressed as d[GaL−]/dt=kGa[Ga3+[H2L2−]+kGaOH[GaOH2+][H2L2−]+kGa(OH)2[Ga(OH)2+][H2L2−]+kGaNCS[GaNCS2+][H2L2−], with kGa=101.23 M−1 s−1 (M=mol dm−3), kGaOH=103.36 M−1 s−1, kGa(OH)2=104.37 M−1 s−1, and kGaNCS=103.90 M−1 s−1 at 25 °C and I=0.50M. The enhanced reactivity of GaA as compared to that of Ga3+ is attributable to the labilizing effect of the bound ligand A on the rate of loss of coordinated water molecules at GaA. Together with the additional formation rate constants of monoisothiocyanato- and monooxalatogallium(III) with 2-hydroxy-2,4,6-cycloheptatrien-1-one, this labilizing effect is quantitatively discussed in terms of the electron-donating ability of the ligand.
Preparation and Characterization of [Co(acetylacetonato)(diamine or 2,2′-bipyridyl)(aminoalkylphosphine)]2+. Crystal Structure of (+)531CD-Λ-fac(N)-(Acetylacetonato){(1R,2R)-1,2-cyclohexanediamine}{(2-aminoethyl)diphenylphosphine}cobalt(III) Perchlorate, [Co(C5H7O2)(C6H14N2)(C14H16NP)](ClO4)2
Authors: Takata Masakazu , Kashiwabara Kazuo , Ito Haruko , Ito Tasuku , Fujita Junnosuke
Published: July 2006

Nine new cobalt(III) complexes of the types, [Co(acac)(L)(edpp)]2+ (L=ethylenediamine(en), (1R,2R)-1,2-cyclohexanediamine(RR-chxn), 2,2′-bipyridyl(bpy)), [Co(acac)(L′)(empp)]2+ (L′=en, bpy), and structurally related [Co(acac)(bpy)(en)]2+ were prepared and resolved into optical isomers, where acac, edpp, and empp denote an acetylacetonate ion, (2-aminoethyl)diphenylphosphine, and (2-aminoethyl)methylphenylphosphine, respectively. The molecular structure of (+)531CD-[Co(acac)(RR-chxn)(edpp)](ClO4)2 was determined by single-crystal X-ray analysis. Crystal data; monoclinic, P21, a=19.562(3)Å, b=16.882(1)Å, c=9.696(1)Å, β=91.22(1)°, V=3201.3(6)Å3, Z=4. Three nitrogen donor atoms in the complex ion are arranged in the facial mannar (fac(N)) and the absolute configuration of the complex ion is Λ. The structures of other complexes were assigned by comparing the 1H NMR and circular dichroism spectra with those of the fac(N)-Λ-[Co(acac)(RR-chxn)(edpp)]2+ complex. The complexes containing a 1,2-diamine yielded selectively the fac(N) isomer, whereas those containing bpy the mer(N) isomer.
Mössbauer, Raman, and DTA Studies on the Structure of BaF2–ZrF4–FeF2 Glasses
Authors: Nishida Tetsuaki , Nonaka Toshiaki , Takashima Yoshimasa
Published: July 2006

Structural studies on the ternary BaF2–ZrF4–FeF2 glasses have been performed to elucidate the local structure of the ZrF4-based glasses which are known to be excellent in the optical transparency and the electric conductivity due to F− ion. Mössbauer and Raman measurements reveal that iron (Fe2+ and Fe3+) plays a structural role similar to that of Ba2+ ion surrounded by eight fluorine atoms at the interstitial site of one- or two-dimensional zigzag chains composed of ZrF6 octahedra. Raman and DTA measurements reveal that the increase in the fraction of BaF2 causes an increase in the coordination number of Zr from 6 to 7. Mössbauer measurements of 25BaF2·65ZrF4·10FeF2 glass at lower temperatures lead to a conclusion that the glass undergoes a phase transition at 225±5K, of which structural change is easily reflected in the isomer shift, quadrupole splitting, and the absorption area. This is supported by the DTA measurement of the same sample at lower temperatures, i.e., the DTA curve consists of two exothermic peaks and a wide endothermic peak observed at about 220–230 K and 180–210 K, respectively.
Determination of Rate Constants for Reactions of Bichloride Anion Radical with Some Dipeptides in Aqueous Solution of KCl and K2S2O8 by Flash Photolysis
Authors: Neda Osamu , Yamauchi Kotaro , Masuda Takahiro
Published: July 2006

Determination of rate constants for reactions of dichloride anion radical was conducted by conventional flash photolysis of aqueous solutions of KCl and K2S2O8, where no participation of HOCL−· is expected in decay kinetics of dichloride anion radical. The optimum conditions found for the determination are 0.1 mol dm−3 KCl and 10−4 mol dm−3 K2S2O8. Under the present experimental conditions, S2O82− serves to convert chloride ion to dichloride anion radical through reaction with hydrated electron produced by photolysis of chloride ion. For glycyltryptophan, the competition method was employed, because its transient absorption overlaps the absorption due to dichloride anion radical. The rate constants determined are almost the same as those obtained in N2O-saturated aqueous solution of KCl (1 mol dm−3). The reactivity of dipeptides toward dichloride anion radical is discussed.
Polarization in Light-scattering by Aerosol
Authors: Matsuzaki Akiyoshi
Published: July 2006

The polarization of the light scattered by aerosol has been studied by the theoretical calculation based on the Mie scattering theory. The present calculation obtains the polarization of the light scattered by aerosol as a function of size parameter, i.e.  x=2πr⁄λ, where r and λ are the radius of aerosol and the wavelength of the scattered light, respectively, for various refractive indexes. These results give the useful informations for the experimental study on the size-growth in aerosol formation by the measurement of the scattered light polarization. The characteristic of the scattered light intensity, which is usually used as a kind of concentration parameter in the study on aerosol formation, is also discussed.
The Iodine-127 Nuclear Quadrupole Resonance of Several Iodine Complexes with Sulfur-containing Organic Molecules
Authors: Terao Hiromitsu , Sakai Hiroshi , Negita Hisao
Published: July 2006

The 127I NQR spectra of 1,4-dithiane–2I2, thiane–I2, 1,4-thioxane–I2, and 1,3,5-trithiane–I2 are reported. Two distinct iodine atoms are observed in the former three complexes, whereas only one iodine atom is present in the last-named complex. The charge densities on the donors and the iodine atoms are obtained according to the Townes-Dailey approximation. The order of donor strength toward the iodine molecule is: thiane>1,4-thioxane>1,4-dithiane>>1,3,5-trithiane. The thioethers can compete with amines in terms of the donor strength to iodine molecules. The no-bond ionic structure of the ground state is less important in the thioether–iodine complexes than in amine–iodine complexes. The positive temperature coefficients found previously in a few similar complexes of amines are observed for the terminal iodine atoms of 1,4-dithiane–2I2, thiane–I2, and 1,4-thioxane–I2. This phenomenon is ascribed to the increasing shift of the dative structure to the no-bond covalent structure with the rise in the temperature.
Voltammetric Studies of the Metal–Ligand Interaction in Low-valent Metal–Olefin π-Complexes. II. Palladium(0) and Platinum(0) Complexes with Olefin–Diimine Mixed Ligands
Authors: Ito Naoyuki , Saji Tetsuo , Aoyagui Shigeru
Published: July 2006

Cyclic voltammograms for the reduction of Pd0 and Pt0 complexes with mixed ligands of diimine and olefin exhibit, respectively, two or four reversible one-electron steps. The half-wave potentials of each step give a straight line with a slope of 1.0, when plotted against the half-wave potentials of diimine ligands, and a slope smaller than 0.2, when plotted aganist the half-wave potentials of olefinic ligands. The half-wave potentials of the complexes are affected only a little by the difference in the central metal. These findings lead to the conclusion that each LUMO of these complexes is dominated by the diimine π*-orbital, though it is higherlying than the olefinic π*-orbital in free ligands.
Bitter Principles of Ailanthus altissima Swingle. Conversion of Ailanthone into Shinjulactone C
Authors: Ishibashi Masami , Tsuyuki Takahiko , Takahashi Takeyoshi
Published: July 2006

Ailanthone was converted into shinjulactone C with a hexacyclic 1α,12α:5α,13α-dicyclo-9βH-picrasane skeleton. The key reaction consists of an intramolecular ionic [4+2] cycloaddition between a pentadienyl cation and an olefin.
Studies with Inorganic Ion-exchange Membranes. I. Effect of Binding Material on the Permeation of Electrolyte Solutions across Titanium Tungstoarsenate Membranes
Authors: Srivastava S K , Kumar Satish , Kumar Surendra
Published: July 2006

A comparative study of permeability for various electrolytes is made on parchment-, polystyrene-, and Araldite based membranes of titanium tungstoarsenate at 20, 25, 30, and 35 °C. At any given temperature the order of permeability increase is K+>Na+>Li+ for 1:1 electrolytes and Ba2+>Ca2+>Mg2+ for 2:1 electrolytes. Permeability values are higher for parchment-based than polystyrene-based membranes. The diffusion of these electrolyte solutions across Araldite based membrane is almost negligible. Thermodynamic parameters of diffusion process, viz., ΔH≠, ΔS≠, ΔF≠ have been evaluated at 25 °C by applying the theory of absolute reaction rates. ΔS≠ values are negative for all the cations for both the membranes except that of Li+ which is positive for parchment-based membranes. ΔF≠ values are higher for the polystyrene-based than parchment-based membranes.
The Fluorescence Lifetimes of Jet-cooled Alkylnaphthalenes
Authors: Ichimura Teijiro , Auty Andrew R , Jones Anita C , Phillips David
Published: July 2006

The measured fluorescence lifetime of the origin of jet-cooled 1-methylnaphthalene is close to that of naphthalene, whereas the corresponding lifetimes of the 2-substituted are longer. The fluorescence lifetime decreased with increasing excitation energy; this can be attributed to an increase in the rate of intersystem crossing with vibrational excitation.
Reaction of Trimethylsilyl Azide with C=N–O Bond
Authors: Nishiyama Kozaburo , Miyata Izumi
Published: July 2006

Trimethylsilyl azide (TMSA) was reacted with an oxime ester or a Reissert salt in the presence of trimethylsilyl trifluoromethanesulfonate to give tetrazole derivative. The details of these reactions are examined.
Desulfurization of Thioketones and Thioamides with Diphosphorus Tetraiodide
Authors: Suzuki Hitomi , Tani Hiroyuki , Takeuchi Setsuko
Published: July 2006

On heating with diphosphorus tetraiodide in benzene, thioketones undergo reductive desulfurization to afford parent hydrocarbons, while thioamides are slowly converted into nitriles.
Absolute Configuration of Platyphylloside and (−)-Centrolobol
Authors: Ohta Shinji , Koyama Mika , Aoki Tadashi , Suga Takayuki
Published: July 2006

The absolute configuration of platyphylloside was established to be S by 13C NMR spectroscopy. On the basis of this establishment, the S-configuration previously assigned to the chirality at C-3 of (−)-centrolobol was revised to the R-configuration.
Studies of Collectors. VI. Application of β-Diketone-type Surfactants to Ion Flotation
Authors: Koide Yoshifumi , Kitaoka Shuichi , Yamada Kimiho
Published: July 2006

β-Diketone-type surfactants(2,4-alkanedione, RnA) were applied as ion-flotation collectors and as extraction reagents. Fe3+, Ga3+, and Cu2+ were floated effectively with RnA as a 1:1 complex from an acidic solution. From a mixture of metal ions(Fe3+, Ga3+, Cu2+, Zn2+, Pb2+, Cd2+, and Ca2+), the Cu2+ was floated selectively at pH 6 by R8A or R12A. Then, the metal ions were extracted with RnA into a benzene layer as coordination-saturated species at regions of a neutral pH. The order of selectivity at pH 6.0 was Fe3+>Cu2+>···. The difference between the properties of RnA as an ion-flotation collector and as an extraction reagent was explained using the HLB value and the surface activity based on the composition of RnA–metal complexes. The metal ions and RnA could be recovered from the scum.
Molecular Deformation Caused by Hydrogen Bonding and Resonance. 1,3-Dimethyl-2-imidazolidinone
Authors: Fukushima Kunio , Haraoka Takashi
Published: July 2006

The Raman spectra of 1,3-dimethyl-2-imidazolidinone were found to change due to a hydrogen bonding to its nitrogen atoms, especially at low temperatures. The change in the spectra included the unusual change for CH2 bending vibrations, suggesting that the deformation of the ring of the molecule takes place by hydrogen bonding.
A Thermodynamic Study on Micellization of Nonionic Surfactant in Water and in Water–Ethanol Mixture by Gel Filtration
Authors: Goto Ayako , Takemoto Masumi , Endo Fumio
Published: July 2006

Micellization of hexa(oxyethylene) dodecyl ether (C12E6) was studied in water and in ethanol–water mixtures at different temperatures by gel filtration on Sphacryl S-200. Standard enthalpies and entropies of micellization were determined from variation of critical micelle concentration(cmc) with temperature. Compensation plots were obtained, slopes for alcohol–water mixtures being indentical with that for pure water. Therefore, the micelle formation in water and ethanol–water mixtures has been explained in terms of its bulk structure. Gel fitration of C12E6 micelle with addition of a large amount of ethanol has led to a finding that the micelle size gradually becomes small with increasing ethanol content until micelles disappear above 35%v/v.
Glass Formation Study of Aqueous HX Solutions (X=F, Cl, and Br)
Authors: Kanno Hitoshi , Satoh Kenji
Published: July 2006

Glass-forming composition regions of aqueous HX solutions (X=F, Cl, and Br) were determined. It was found that oxonium ions play an important role in glass-forming behavior of these solutions. Including the results for HI solution previously reported, the general trends of glass-formation behavior of aqueous HX solutions are summarized.
Kinetic Analysis of the High-pressure Diels-Alder Reactions of Tropone with Maleic Anhydride and Norbornene
Authors: Takeshita Hitoshi , Sugiyama Shigeru , Hatsui Toshihide
Published: July 2006

The kinetics of Diels-Alder reactions of tropone with maleic anhydride and norbornene were studied at pressures up to 2000 bar. The activation volumes, obtained from the former at 378.2 K in isopropylbenzene (IPB) and N,N-dimethylformamide (DMF), were ΔV≠(IPB)=−21.4 cm3/mol and ΔV≠(DMP)=−16.8 cm3/mol. Those from the latter (at 408.2 K) were ΔV≠(IPB)=−30.0 cm3/mol and ΔV≠(DMF)=−27.8 cm3/mol. These ΔV≠ and ΔV showed a large deviation from those of the (6+4)π process of tropone with cyclopentadiene (by le Noble) and a small deviation from those of other typical Diels-Alder reactions to support the concerted cycloaddition mechanism which has been established by the kinetic analysis at atmospheric pressure.
Critical Peptide Size for Insolubility Caused by a β-Sheet Aggregation and Solubility Improvement in Hydrophobic Peptides by Replacement of Alanine Residues with α-Aminoisobutyric Acid Residues
Authors: Narita Mitsuaki , Chen Junn-Yann , Sato Hiroyuki , Kim Yukio
Published: July 2006

In order to demonstrate an important role of a β-sheet aggregation on insolubility of peptides, hydrophobic peptides having partial amino acid sequences found in natural proteins have been prepared by the step-wise elongation and fragment condensation methods. In conformity with the solubility prediction for protected peptides in our previous paper, solubility data indicate that insolubility of peptides appears to begin at octa- or nonapeptide levels. In hydrophobic sequences found in proteins, the structure of peptide backbones, namely, the β-structure clearly plays an important role on insolubility of peptides, but the composition of peptides does not. Solubility improvement in hydrophobic peptides included in α-helical regions of proteins is easily achieved by replacement of Ala residues with Aib residues. High solubility of the peptides containing Aib residues is clearly explained by the observation that replacement of Cα hydrogen atoms with methyl groups greatly disturbs β-sheet structures, promoting helical folding in peptides. The great ability of an Aib residue to promote helical folding is distinctly revealed in the peptide fragments included in α-helical regions of proteins as demonstrated before in model oligo(Leu)s.
A New Synthetic Method of Alkyl Carbonocyanidate N-Oxides
Authors: Shimizu Tomio , Hayashi Yoshiyuki , Teramura Kazuhiro
Published: July 2006

A thermal decomposition of dimethyl nitromalonate to bis(carbomethoxy)furoxan was observed at about 170 °C. In the presence of dipolarophiles, an intermediate, methyl carbonocyanidate N-oxide MeOCOC≡N→O, could be trapped as cycloadducts in good yields by the 1,3-dipolar cycloaddition. Treatment of dimethyl nitromalonate in mesitylene at the refluxing temperature resulted in a formation of methyl 2-(hydroxyimino)-2-(2,4,6-trimethylphenyl)acetate.
Hydroxylation of Cedrol by m-Chloroperbenzoic Acid. Synthesis of an Epimer of the Alleged “Senoxydene”
Authors: Tori Motoo , Matsuda Reiko , Asakawa Yoshinori
Published: July 2006

Cedrol was hydroxylated by m-chloroperbenzoic acid to give four tertiary alcohols and two secondary alcohols, one of which was converted into an epimer of “senoxydene” in four steps.
Ring-cleavage Reactions of Aromatic Hydrocarbons Studied by FT–IR Spectroscopy. I. Photooxidation of Toluene and Benzene in the NOx–Air System
Authors: Bandow Hiroshi , Washida Nobuaki , Akimoto Hajime
Published: July 2006

The products of the atmospheric photooxidation reactions of toluene and benzene were analyzed quantitatively using long-path FT–IR spectroscopy. Methylglyoxal (only in the case of toluene), glyoxal and maleic anhydride were observed as aromatic ring-cleavage products. In the toluene photooxidation, yields of methylglyoxal, glyoxal, and maleic anhydride were 14±4, 15±4, and 4.0±0.4% (mole/mole), respectively. The formation of small molecules, formaldehyde and formic acid, was observed. It is suggested that the precursor of the ring-cleavage reaction is OH–aromatics–O2 adducts, and that the α-dicarbonyls and unsaturated γ-dicarbonyls are produced by ring cleavage after cyclization of the OH–aromatics–O2 adduct. The observation of maleic anhydride is considered as an evidence of the aromatic ring cleavage into C2 and C4 fragments. The fraction of the ring cleavage process in the total reaction is 29 and 15–20% in the cases of toluene and benzene, respectively.
Effect of Methyl Substitution in 1,2-Ethanediaminenickel(II) Complexes upon Their Thermal Stabilities
Authors: Tsuchiya Ryokichi , Uehara Akira , Suzuki Masatatsu , Matsuda Akira
Published: July 2006

The enthalpy changes (ΔH) in the reaction of three types of the nickel(II) complexes, [Ni(AA)2(H2O)2]X2·nH2O, [NiX2(AA)2], and [Ni(AA)2]X2, with aqueous potassium cyanide solution were calorimetrically measured at 25 °C, where AA denotes a diamine selected from 1,2-ethanediamine (en), N-methyl-1,2-ethanediamine (N-men), N,N-dimethyl-1,2-ethanediamine (NN-dmen), N,N′-dimethyl-1,2-ethanediamine (NN′-dmen), and N,N,N′-trimethyl-1,2-ethanediamine (NNN′-tmen); X is Cl, Br, I, NO3, or ClO4; n=0, 2, or 3. The thermal stabilities of the complexes in the solid state defined by the enthalpy changes (not by the free energy changes) were compared with one another, so that the thermal stabilities of the complexes are highly dependent on numbers and/or positions of N-methyl groups on diamines. In the series of [NiX2(AA)2] and [Ni(AA)2]X2 type complexes, the NN′-dmen complexes are the most stable. Except for the NN′-dmen complexes, as the numbers of N-methyl group(s) contained in the diamines increase, the complexes have the tendency to become less stable. The relative thermal stabilities of the present complexes were discussed in terms of the basicities of diamines and steric effect of N-methyl groups.
Class Separation of Higher Hydrocarbons by Thin-Layer Chromatography with Flame Ionization Detection
Authors: Yamamoto Yojiro
Published: July 2006

3-Aminopropyl or 3-cyanopropyl-bonded silica-gel thin-layer rods (Chromarod NH2–SII or CN–SII) were prepared and a hydrocarbon class separation of higher hydrocarbons has been investigated by flame ionization detection–thin-layer chromatography (FID–TLC) with those rods as the stationary phase. The resolutions (Rs) of the class separation with Chromarod NH2–SII and CN–SII were compared with those with conventional rods on the market, which were silica-gel-sintered (Chromarod S and SII) and alumina-gel-sintered (Chromarod A) thin-layer rods. An adequate class separation of higher hydrocarbons into Saturates (Sa), Monoaromatics (M-Ar), Diaromatics (D-Ar) and Triaromatics (T-Ar) could be performed by FID–TLC with Chromarod NH2–SII or CN–SII.
Kinetic Studies of Fast Equilibrium by Means of High-performance Liquid Chromatography. X. Separation of Rotamers of Acetanilides
Authors: Moriyasu Masataka , Kawanishi Kazuko , Kato Atsushi , Hashimoto Yohei , Sugiura Makiko
Published: July 2006

The restricted rotation about the carbonyl–nitrogen bonds of acetanilides has been investigated by means of high-performance liquid chromatography. The separation of two rotamers (E- and Z-forms) of acetanilides has been achieved at low temperatures. The presence of a very small amount of the E-form has been confirmed for 3-, 4-, and non-substituted acetanilides. The ratios of the E- and Z-forms in different solvents have also been determined. By combining the HPLC and NMR results, it has been elucidated that the molecular structure of acetanilide in solution can be described in terms of an equilibrium between a large amount of the nearly planar Z-form and a small amount of the twisted E-form.