bluuebunny/crossref_metadata_2025 huggingface dataset:
Steric Control in the Diels-Alder Reaction
Authors: Seguchi Kazuyoshi , Sera Akira , Maruyama Kazuhiro
Published: July 2006

The Diels-Alder reactions of polychlorocyclopentadienes with substituted ethylenes were investigated, and the rates of the reaction and the endo : exo adduct distributions were determined. The introduction of a chlorine atom at the C5 position of cyclopentadiene resulted in an enhanced endo preference for substituents in the adducts, despite the depressed reactivity of the diene. This is contrary to what is to be expected from the so-called “selectivity-reactivity relationship in the Diels-Alder reaction.” The results in this work were explained in terms of steric interaction between the C5-chlorine atom of the diene and the substituent of dienophiles.
The Solution Photodimerization of (E)-p-Nitrocinnamates
Authors: Ishigami Tatsuzo , Murata Tomoji , Endo Tadashi
Published: July 2006

The solution photodimerization of methyl (E)-p-nitrocinnamate has been studied under various conditions. Cis and trans dimers of head-to-head configuration were formed predominantly, the ratio of the dimers being highly dependent on the concentration and the solvent. The sensitization, the quenching phenomena, and the external heavy-atom effect were observed in this photodimerization. It appears likely that the excited multiplicity responsible for the formation of the trans-dimer is the triplet π,π* state and that both the singlet and the triplet π,π* states contribute to the production of the cis-dimer.
pH Effects on the Radical Addition of Hydrogensulfite Ion to Olefins
Authors: Sakumoto Akihisa , Miyata Teijiro , Washino Masamitsu
Published: July 2006

The competitive addition of sodium hydrogensulfite to allyl and 2-methylallyl alcohols was investigated at the pH range from 3 to 5. The relative reactivity of allyl alcohol to 2-methylallyl alcohol decreased with increasing pH. Sulfite radical ion was mainly participating in the addition at pH 5, and hydrogensulfite radical at pH 3. From the kinetic analysis of the pH dependence, the ratio of reactivities of allyl alcohol and 2-methylallyl alcohol toward sulfite radical ion was 0.213, and the same ratio toward hydrogensulfite radical was 0.305. Further, the ratio of reactivities of hydrogensulfite radical and sulfite radical ion toward allyl alcohol was 1.32, and the same ratio toward 2-methylallyl alcohol was 0.927. The dissociation constant of hydrogensulfite radical was the order of 3×10−5(pKa=4.5).
Synthesis of Porcine Motilin by Fragment Condensation Using Three Protected Peptide Fragments
Authors: Shimizu Fumio , Imagawa Kenichi , Mihara Shigeru , Yanaihara Noboru
Published: July 2006

Synthesis of porcine motilin is described. Construction of the entire molecule of this hormone was carried out by the fragment condensation method in solution employing Rudinger’s azide modification, and the resulting protected docosapeptide was deblocked by sodium–liquid ammonia procedure. Purification of the final product was performed by ion exchange chromatography on CM-Sephadex using ammonium acetate as eluent and gel filtration on BiO–Gel P-6. Purity of the synthetic docosapeptide was assessed by TLC in two different solvent systems and amino acid analysis. This polypeptide showed gastric motoractivity stimulating action on 30 min intravenous infusion in dogs in 5 ng/kg/min doses, which is characteristic to porcine motilin.
Substituent Effect on the Dissociation Constants of 5-(Substituted Styryl)-2-aminotropones
Authors: Kobayashi Toshio , Imafuku Kimiaki , Matsumura Hisashi
Published: July 2006

The dissociation constants of various 5-styryl-2-aminotropones were determined spectrophotometrically using 50%(v/v) aqueous methanol and correlated by the use of Hammett equation, with ρ=0.57.
N-Halogen Compounds of Cyanamide Derivatives. VIII. A Convenient Method of Preparing 1,2,4-Oxadiazoles from N-Haloamidino Compounds
Authors: Fuchigami Toshio , Odo Keijiro
Published: July 2006

A new, efficient method for the preparation of 1,2,4-oxadiazoles from N-benzoylamidino compounds by treatment with t-butyl hypochlorite and sodium hydroxide has been devised. It was supposed that the ring formation proceeds via a nitrene intermediate.
Synthesis of Streptolidine from d-Xylose
Authors: Kusumoto Shoichi , Tsuji Shinichi , Shima Keiyuu , Shiba Tetsuo
Published: July 2006

An alternative total synthesis of streptolidine (roseonine, geamine) was achieved starting from d-xylose. Direct azidolysis of methyl 2,3,5-tri-O-mesyl-α-d-xylofuranoside (6a) afforded methyl 2,3,5-triazido-2,3,5-trideoxy-α-d-arabinofuranoside (9a), whereas the β-anomer of 6a gave only 3,5-diazido-3,5-dideoxy-2-O-mesyl-β-d-ribofuranoside (8b) indicating that the glycosidic configuration in the furanoside system has a decisive influence on the reactivity of the 2-mesyloxy group. However, the β-anomer of diazide (8b) was anomerized to α-anomer which readily undergoes azidolysis to give the triazide (9a). The triazide was successively hydrogenated, benzyloxycarbonylated, and then hydrolyzed to give 2,3,5-tris(benzyloxycarbonylamino)-2,3,5-trideoxy-d-arabinofuranose, which was identical with that prepared from d-ribose. Streptolidine could be synthesized from this key intermediate.
Mechanism of the Optical Activation of α-Substituted Carbonyl Compounds via Optically Active Immonium Salts
Authors: Matsushita Hajime , Tsujino Yasuko , Noguchi Masao , Yoshikawa Sadao
Published: July 2006

The degree of the optical activations of racemic α-substituted carbonyl compounds via the formation of optically active immonium salts and the subsequent hydrolysis were largely affected by acids used for the hydrolysis of the enamines. The ratio of the diastereomeric immonium salts depends on the temperature. There is a relationship between the configuration of the optically activated carbonyl compounds and those of amines used. These suggest that the optical activation is due to the asymmetric transformation.
Thermal Separation Column with Vertical Barriers. I. Analytical Studies on the Thermal Separation Column Having Vertical Barriers
Authors: Sasaki Kazuo , Yoshitomi Tsutomu , Miura Norio
Published: July 2006

The effect of installing a couple of vertical flow barriers inside a double cylinder-type thermal separation column has been studied analytically. The method of analysis is entirely similar to that developed by Jones and Furry. The only change is that an additional parameter, which specifies the location of the barriers, has been introduced. The results indicated that the installation of barriers retards the convectional velocity and leads to a remarkable increase in the equilibrium separation. With the optimum design, which is achieved by locating barriers at 5/8 parts of the half-width of the wall spacing, the logarithmic equilibrium separation will become 4 times greater than that in the open column.
Reactions of Transition Metal Dihydrides. VII. Further Investigations on Charge-Transfer Interaction between σ-Basic Metal Hydrides and Organic π-Acceptors
Authors: Nakamura Akira , Otsuka Sei
Published: July 2006

Charge transfer (CT) absorptions between transition metal polyhydrides, e.g. MH2Cp2 (Cp=η-C5H5; M=Mo, W), FeH2(dppe)2, MH4(dppe)2(dppe=Ph2PCH2CH2PPh2; M=Mo, W), and organic π-acceptors such as maleic anhydride were measured. The position of the CT bands gave an Ip value of 6.3 eV for WH2Cp2. The value indicates transfer of electron from the filled non-bonding metal orbital to the acceptors. Role of the electron donor-acceptor interactions prior to insertion or substitution of transition metal hydrides is discussed.
Synthesis of 3′-Deoxykanamycin B (Tobramycin)
Authors: Takagi Yasushi , Miyake Toshiaki , Tsuchiya Tsutomu , Umezawa Sumio , Umezawa Hamao
Published: July 2006

3′-Deoxykanamycin B (tobramycin) was prepared from kanamycin B. 3′,4′:4″,6″-Di-O-cyclohexylidene derivative (2) of penta-N-ethoxycarbonylkanamycin B was 2″-O-benzoylated and the 3′,4′-O-cyclohexylidene group was selectively and quantitatively removed by treatment with 1 mol equivalent of water in N,N-dimethylformamide (DMF) to give the de-3′,4′-O-cyclohexylidene derivative (4). Regioselective tosylation in pyridine at −20 °C gave the 3′-O-tosyl derivative (5) in 70% yield. Despite the 1,3-diaxial interaction in the transition state, replacement of the tosyl group with iodide was successfully performed in high yield with NaI in DMF. Hydrogenolysis of the iodo derivative (6) and subsequent removal of the protecting groups gave 3′-deoxykanamycin B (10) in ≈25% overall yield from kanamycin B. Confirmation of the 3′-deoxy group was performed by measurement of Δ[M]TACu of 3′-deoxyneamine which was obtained from 10 by hydrolysis.
Thermal Separation Column with Vertical Barriers. II. Performance of a Thermal Separation Column with Vertical Barriers
Authors: Sasaki Kazuo , Miura Norio , Yoshitomi Tsutomu
Published: July 2006

The performance of a newly designed thermal separation column has been examined. The apparatus was constructed along the line of mathematical analysis developed in the preceding paper. The column was basically composed of two coaxial cylinders inside of which two additional cylinders of fine stainless steel screen were installed to control the gas flows in the column. An equimolar mixture of argon and nitrogen was used as the test gas. A definite improvement in the magnitude of equilibrium separation was demonstrated in accordance with the theory. In addition, the rate of attainment of steady state was found not so much different from that with open column when temperature exceeded 140 °C or more.
Direct Observation of Dienol Intermediates in Photochemical Deconjugation of an α,β-Uusaturated Ketone. Photoisomerization of 1-Acetylcyclooctene
Authors: Noyori Ryoji , Inoue Hiroshi , Katô Masao
Published: July 2006

The photolysis of 1-acetylcyclooctene in acetonitrile solution leads to 3-(α-hydroxyethylidene)cyclooctene (two stereoisomers). Structures of the stable 1,3-dienols have been elucidated on the basis of their spectral data and chemical behavior. The dienols are highly air-sensitive. Upon heating, or by the action of an acid or base, they are converted to 3-acetylcyclooctene. In methanol-O-d, 3-acetylcyclooctene-3-d is formed. These findings provide the first, unambiguous evidence for the intervention of 1,3-dienol intermediates in photochemical deconjugation of an α,β-unsaturated ketone into the β,γ isomer.
Studies of the π,π* Absorption Bands of 2,6-Dimethyl-4-pyrone
Authors: Kuboyama Akira , Sato Yoshikuni , Arano Hiroshi
Published: July 2006

The π,π* S-S absorption spectra of 2,6-dimethyl-4-pyrone in solutions up to the vacuum UV region were obtained. Based on the results of the MO calculations, the assignment and characterization of the observed π,π*, bands were studied, together with the assignment of the π,π* bands near 250 nm of 4-pyrone.
Oxidation-Reduction Potentials in the Formation of Anion Radicals
Authors: Iida Yôichi
Published: July 2006

The oxidation-reduction potentials in the formation of anion radicals were determined by using the equilibrium constant of the preferred electron transfer reaction between anion radicals in acetonitrile solution.
A Simple Method for Measuring Mass Spectra of Ions with Excess Kinetic Energy
Authors: Tajima Susumu , Nakamura Mitsuo , Azami Tadashige , Tsuchiya Toshikazu
Published: July 2006

Mass spectra of ions with excess kinetic energy have been measured by applying a small negative voltage to the repeller electrode.
Photochemical Addition Reactions of Methanol and Ethanol to 1,4-Diaminoanthraquinone
Authors: Yamada Kimiho , Shosenji Hideto , Fukunaga Seiki , Hirahara Kazuyoshi
Published: July 2006

Photochemical reactions of 1,4-diaminoanthraquinone in methanol and/or ethanol yielded solvent adducts, 4a and 4b. The reactions proceeded via an upper triplet state. The quantum yields were 0.013–0.019 at 280 nm.
Effects of Quinones on the Protonation Reaction of TCNQ Anion Radical; The Role of a Protonated Quinone as a Strong Electron Acceptor
Authors: Yamagishi Akihiko , Yamada Mutsuo
Published: July 2006

Various kinds of substituted p-benzoquinones (Q) have been found to accelerate the rate of the reaction between 7,7,8,8-tetracyanoquinodimethane(TCNQ) anion radical and hydrogen chloride in acetonitrile. The stoichiometry of the reaction is altered by the presence of Q from 2TCNQ\ewdot+2H+=TCNQ+H2TCNQ to 2TCNQ\ewdot+2H++Q=2TCNQ+QH2. In case of p-benzoquinone, the rate of the disappearance of TCNQ\ewdot is expressed by v=k[TCNQ\ewdot] [Q] [H+], where k=3.0×108 M−2 s−1 at 8 °C. From these results, it is concluded that a protonated quinone QH+ is an active species which accepts an electron from TCNQ\ewdot.
Photo-induced Reaction of 2-Alkoxy-3-bromo-1,4-naphthoquinones with Acetylenes: Formation of 2-Aryl-substituted Naphtho[2,3-b]furan-4,9-diones
Authors: Otsuki Tetsuo
Published: July 2006

2-Aryl-substituted naphtho[2,3-b]furan-4,9-diones 3 were obtained as a major product in the photo-chemical reaction of 2-alkoxy-3-bromo-1,4-naphthoquinones with acetylenes.
Solid-State Circular Dichroism Spectra of Tris(diamine)cobalt(III) Complexes: Decomposition into E and A2 Components
Authors: Kuroda Reiko , Saito Yoshihiko
Published: July 2006

Solid-state circular dichroism spectra of some tris(diamine) cobalt(III) complexes were measured. Each CD band region was decomposed into E and A2 components by combining the CD spectra in uniaxial single-crystals and in microcrystalline states. The observed values of R(E) and R(A2) were compared with the theoretical calculation of Mason and Seal based on dynamic coupling method. The agreements are generally good for those complexes with five-membered chelate rings, however, there are some discrepancies for six- and seven-membered chelate ring cases.
Magnetic Circular Dichroism of the Iron(III) Porphins
Authors: Kobayashi Hiroshi , Higuchi Tadatoshi , Eguchi Ken
Published: July 2006

Magnetic circular dichroism (MCD) spectra were measured of some low-spin and high-spin Fe(III) porphins in a rigid matrix of polymethyl methacrylate(PMMA) for a variety of temperature. Some of the most prominent MCD, extrema of the low-spin Fe(III) porphins showed a remarkable enhancement of the intensity at reduced temperatures, while no appreciable increase was observed in the absorption intensity. The temperature dependence of the MCD dispersion of the low-spin Fe(III) porphins arises, in principle, from a change in the Boltzmann distribution between the ground Kramers doublet splitting in a magnetic field, however, the MCD enhancement observed in the Soret region can correctly be interpreted only when the excited states described by a product wave function of the porphin B state and the spin-orbit coupling substates of low-spin iron(III) d5 system are split by a configuration interaction with the “porphin to iron(III)” charge-transfer excited states.
Vibrational Spectra and Rotational Isomerism of Alkyl Vinyl Ethers
Authors: Sakakibara Masaaki , Inagaki Fuyuhiko , Harada Issei , Shimanouchi Takehiko
Published: July 2006

The rotational isomerism of methyl vinyl ether, ethyl vinyl ether, and n-butyl vinyl ether has been studied by means of the vibrational spectra and normal frequency calculations. The enthalpy difference between the skew and cis isomers in the liquid state of methyl vinyl ether has been determined to be 1440±160 cal/mol. Series of C–O torsional transitions in the cis well have been observed for methyl vinyl ether and methy-d3 vinyl ether in the region near 230 cm−1 and analyzed. It has been concluded for ethyl vinyl ether that the cis-trans form (CT) is stable in the solid state and that three forms, CT, SG′, and ST, coexist in the liquid and gaseous states. The spectra in the solid state of n-butyl vinyl ether are consistent with the calculated frequencies of the CTTT form.
Metal Complexes of Amino Acids. IX. Carbon-13 Nuclear Magnetic Resonances of Cobalt(III) Complexes
Authors: Ama Tomoharu , Yasui Takaji
Published: July 2006

The 13C NMR spectra of cobalt(III) complexes containing various amino acids as unidentate or bidentate ligands were measured. The relation between the coordination types and the changes of the chemical shifts was clarified. The changes of chemical shift on coordination of α-amino acid to cobalt(III) (NH3+–R–COOH→NH3+–R–COOCo) were about 7 and 1 ppm for the carboxy-carbon and α-carbon, respectively. On the other hand, those on chelation (NH3+–R–COOH→chelated amino acid) were about 15 and 5 ppm for each carbon, respectively. However, the changes of chemical shift on chelation of β-alanine were different from those of α-amino acids.
Photooxygenation of α,β- and β,γ-Unsaturated Enamines in 17-(1-Formylethyl)etiojervanes
Authors: Murai Akio , Sato Chizuko , Sasamori Hiroshi , Masamune Tadashi
Published: July 2006

Photooxygenation of α,β(13,17)- and β,γ(12,13)-unsaturated morpholine enamines (I and II) in 17-(1-formylethyl)etiojervanes by singlet oxygen was carried out under irradiation with fluorescent bulbs. Oxidation of the former (I) afforded the corresponding α,β-unsaturated ketone (III) as the only product which could be isolated, while that of the latter gave two products, one (IV) being a normally oxidized β,γ-unsaturated ketone and the other (VIII) an α,β-unsaturated ketone with the D-ring contracted. Compound (VIII) was not obtained by treatment of IV under the same photooxygenation conditions as for II, indicating that the formation of VIII would not involve IV as an intermediate.
Photochemical Cycloaddition Reactions of α,β-Unsaturated Lactones with Olefins, and Application to Synthesis of Natural Products
Authors: Kosugi Hiroshi , Sekiguchi Shizuo , Sekita Ryû-ichi , Uda Hisashi
Published: July 2006

The photochemical cycloaddition reactions of five- and six-membered α,β-unsaturated lactone derivatives with unsaturated substrates (ethylene, acetylene, 1,1-dimethoxyethylene etc.) have been studied. The parent α,β-unsaturated lactone (γ-crotonolactone) and the β-,γ-, or δ-alkyl substituted derivatives add to ethylene and acetylene in the acetone solutions and to 1,1-dimethoxyethylene in the benzene solutions in so good yields as to utilize them practically for synthesis. α-Phenyl-γ-crotonolactone and β-phenyl-γ-crotonolactone also add to ethylene and acetylene, whereas, α-methyl, β-hydroxy, and β-methoxy derivatives do not. As the synthetic applications of the reactions, the synthesis of (±)-grandisol has been achieved, and the synthetic approach to (±)-canadensolide has also been described.
Chemistry of Nitrosoimines. XIV. Photolysis of 5-Nitrosoimino-4-phenyl-3-phenylimino-1,2,4-thiadiazolidine
Authors: Akiba Kin-ya , Tsuchiya Tohru , Fukawa Isaburo , Inamoto Naoki
Published: July 2006

Photolysis of 5-nitrosoimino-4-phenyl-3-phenyliraino-1,2,4-thiadiazolidine proceeded through π-π* excitation and gave phenylcyanamide and 5-imino-4-phenyl-3-phenylimino-1,2,4-thiadiazolidine as primary products. It was found that other products were produced by the reactions of the primary products. The formation mechanisms have been discussed briefly.
A Study of Catalysis by Metal Phosphate. III. The Dehydrogenation of Alcohols over Cadmium Phosphate and the Influence of CCl4 Addition on the Catalytic Reaction
Authors: Nozaki Fumio , Iimori Yutaka
Published: July 2006

Various alcohols were selectively dehydrogenated over the Cd3(PO4)2 catalyst. The addition of CCl4 during the reaction resulted in a rapid decrease in dehydrogenation activity and in an increase in dehydration activity, accompanied by an evolution of CO2.
Synthetic Reacions by Complex Catalysts. XXXVIII. A New Preparation of Copper(I) Isocyanate(Alkyl Isocyanide) and Its Reactions
Authors: Ito Yoshihiko , Inubushi Yoshinori , Matsumura Shun-ichi , Saegusa Takeo
Published: July 2006

Reaction of ethyl carbamate with Cu2O in the presence of t-butyl isocyanide produces copper (I) isocyanate (t-butyl isocyanide) complex, Cu(NCO)(t-C4H9-NC)2.5 (1), in 93% yield. Complex 1 is also produced in high yield by the reaction of ethyl N-trimethylsilylcarbamate with Cu2O in the presence of t-butyl isocyanide. Complex 1 reacts with alkyl halides in alcohols and with acyl chlorides to afford N-alkylcarbamate (2) and acyl isocyanate (3), respectively, in moderate yields.
The Acidities of Substituted α-Phenylsulfinylacetophenones
Authors: Kunieda Norio , Fujiwara Yoichi , Nokami Junzo , Kinoshita Masayoshi
Published: July 2006

The acidities of eleven meta- and para-substituted α-phenylsulfinylacetophenones (1) were determined potentiometrically in a 50% ethanol solution. pKa values (10.22–12.01) which can be nicely correlated with Hammett’s σ-values were obtained.
Dynamic Behavior of Acetylacetonato, Triphenylphosphine and Alkyl Ligands in NiR(acac)(PPh3)n (R=C2H5, CH3) in Solution and Disproportionation of the Alkylnickel Complexes in Pyridine
Authors: Yamamoto Takakazu , Saruyama Toshio , Nakamura Yoshiyuki , Yamamoto Akio
Published: July 2006

Dynamic behavior of acetylacetonato (acac), triphenylphosphine (PPh3) and ethyl (in the case of 1) ligands of NiR(acac)(PPh3)n (R=C2H5, n=1 (1); R=CH3, n=2 (2)) in solution has been studied. PPh3 ligand(s) in 1 and 2 exchange rapidly on NMR time scale with free PPh3 in solution. Addition of excess PPh3 makes the exchange rate much faster and an SN2 mechanism is proposed to explain the acceleration effect. 31P-NMR spectrum of 1 in pyridine shows that the PPh3 ligand is replaced by the solvent molecule. Acac ligands in 1 and 2 also undergo rapid interchange on NMR time scale. The activation energy for the acac interchange is about 10 kcal/ mol. On standing a specifically deuterated ethylnickel complex, Ni(CH2CD3)(acac)(PPh3) 1-d3 in solution, the hydrogens and deuteriums in the ethyl group were scrambled. Appearance of the methyl proton signals in the 1H-NMR spectrum of the deuterated ethylnickel complex after the treatment in solution demonstrates the occurrence of the H–D scrambling in solution. Both 1 and 2 undergo disproportionation reactions in pyridine. The rate of the disproportionation is second-order with respect to the concentration of 2.
The Crystal and Molecular Structure of Zinc Complex of 2-Chlorobenzoic Acid. II. The Crystal and Molecular Structure of μ3-Hydroxo-tri-μ-(2-chlorobenzoato)dizinc(II) Dihydrate
Authors: Nakacho Yoshifumi , Misawa Takeshi , Fujiwara Takaji , Wakahara Akio , Tomita Ken-ichi
Published: July 2006

C21H12O6Cl3Zn2OH·2H2O crystallizes in the monoclinic space group P21/c: a=12.779, b=23.732, c=14.749 Å, β=147.98°, and Z=4. The structure was determined by the usual heavy atom method and refined to R=0.039. The complex forms polymeric complex chains in the crystalline state. The ligands around two independent zinc atoms form an unusual trigonal bipyramid and an octahedron, respectively; the coordination geometry apparently differs from that found in the crystal structure of bis(2-chlorobenzoato) zinc(II). The correlation between coordination geometry and catalytic action of zinc atom is also discussed.
The Radiolysis of Anthraquinone Dye in Aqueous Solutions
Authors: Suzuki Nobutake , Nagai Takeshi , Hotta Hiroshi , Washino Masamitsu
Published: July 2006

The decoloration yields of an Acid Blue 40 neutral aqueous solution, G(-Dye), obtained from the optical density at 610 nm for the nitrogen-, oxygen-, and N2O-saturated solutions, equaled 0.18, 0.29, and 0.51 in the respective early stages. In view of the effects of NCS− and NO3− on the G(-Dye), the decoloration is attributable to the attacks of the OH radicals and hydrated electrons on the dye. The rate constants for the reactions of the OH radical and the hydrated electron with Acid Blue 40, obtained from competition reactions with various additives, were (6.6±1.2)×109 M−1s−1 and 1.5×1010 M−1s−1 respectively. In the nitrogen-saturated solutions, the G(-Dye) increased markedly upon the addition of alcohols–for example, up to 1.25 upon the addition of 2 mM butyl alcohol. In this case, at the same time, a new absorption band which is attributable to the formation of the reduction products by the attacks of the hydrated electrons and alcohol radicals on the dye appeared at 460–490 nm. This new absorption band disappeared slowly in the presence of oxygen; the rate of this disappearance was 2.8×10−5s−1. On the other hand, in the oxygen-saturated solutions, the G(-Dye) decreased markeld upon the addition of even a small amount of alcohol.
Optical Activity of Biphenyl Derivatives: The π–π* and n-π* Transitions of o,o′-Dinitrobiphenyls
Authors: Hanazaki Ichiro
Published: July 2006

The optical rotatory power for the lower electronic transitions of several o,o′-dinitrobiphenyl derivatives is examined on the basis of a theoretical method previously developed and applied to metal chelate compounds and binaphthyl derivatives. The theoretical energy, absorption intensity, and rotational strength are shown to be in reasonable agreement with the observed absorption and circular dichroism spectra, confirming the applicability of the theory to the optical activity of this simple type of dissymmetric molecules. In addition, the origin of the rotational strength for the n-π* transition is examined in detail. The results indicate that the n-π* transition gains its intensity and rotatory power through the interaction of the nonbonding electrons in a nitro group with the π electron system in the other nitrobenzene ring.
Hydration of Pyridine Bases in Benzene
Authors: Hirose Katsumi , Tanaka Motoharu
Published: July 2006

Hydration of pyridine bases in benzene has been studied by partition at 25 °C, the total concentration of pyridine bases being less than 1.0 M in benzene. The studied pyridine bases include pyridine, 2-methylpyridine, 4-methylpyridine, 2,6-dimethylpyridine, 3,5-dimethylpyridine, 2,4,6-trimethylpyridine, 2-chloropyridine, 2-bromopyridine, 3-bromopyridine and 2,6-dibromopyridine. Hydrated species with different composition are formed: the composition of the hydrated species (base to water ratio) is as follows: (1 : 2) for 2,6-dibromopyridine, (1 : 1) and (1 : 2) for 2-chloro- and 2-bromopyridine, (1 : 1) and (2 : 1) for 3-bromopyridine, (1 : 1), (1 : 2) and (2 : 1) for 4-methylpyridine and pyridine itself, and (1 : 1), (1 : 2), (2 : 1) and (2 : 2) or (2 : 3) for the other methyl derivatives. A linear free energy relationship has been observed between the hydration in benzene for the monomer monohydrate and the protonation in water of the corresponding base.
Molecular Structures of 5-Thiabicyclo[2.1.1]hexane and 7-Thianorbornane as Studied by Gas Electron Diffraction
Authors: Fukuyama Tsutomu , Oyanagi Kazuko , Kuchitsu Kozo
Published: July 2006

Molecular structures of 5-thiabicyclo[2.1.1]hexane and 7-thianorbornane (7-thiabicyclo[2.2.1]heptane) were studied by gas electron diffraction. For 7-thianorbornane the rotational constants obtained by Hirota et al. by microwave spectroscopy were also taken into account. Least-squares analyses gave the following rg bond distances and valence angles (rα for 5-thiabicyclo[2.1.1]hexane and rav for 7-thianorbornane): for 5-thiabicyclo[2.1.1]hexane, (C1–C2, C2–C3)av=1.539±0.016 Å, C1–C6=1.564±0.024 Å, C–S=1.865±0.004 Å, (C–H)av=1.110±0.008 Å, ∠C–S–C=69.5±0.6 ° and the dihedral angles (C1SC4)-(C1C2C3C4)=115.2±1.7° and (C1C6C4)-(C1C2C3C4)=116.1±2.4°; for 7-thianorbornane, C1–C2=1.538±0.006 Å, C2–C3=1.561±0.015 Å, C–S=1.837±0.004 Å, (C–H)av=1.115±0.008 Å, ∠C–S–C=80.2±0.8 °, the dihedral angle (C1C2C3C4)-(C4C5C6C1)=115.0±1.2° and ∠C1H–C–H=106±5°. The uncertainties represent the estimated limits of experimental error. The C–S bond length in 5-thiabicyclo[2.1.1]hexane is longer than that in dimethyl sulfide by 0.06 Å and that in 7-thianorbornane by 0.03 Å. The C–S–C angle in 5-thiabicyclo[2.1.1]hexane is smaller than that in dimethyl sulfide by about 30° and that in 7-thianorbornane by about 11°. The C1–C6 bond in 5-thiabicyclo[2.1.1]hexane is longer than the weighted average of the C1–C2 and C2–C3 bond lengths. The C1–C2 bond in 7-thianorbornane is longer than the C2–C3 bond.
Effect of Temperature on the Infrared Spectroscopic Parameters of Hydrogen Bonds between Some Phenols and Nitrites
Authors: Jawed Inam
Published: July 2006

The effect of temperature on the infrared spectroscopic parameters of hydrogen bonds between a number of phenol-nitrile systems has been studied. The. infrared frequency shift always decreases with increase in temperature. The variation of half width of the hydrogen bonded band, however, is not regular and is within the error of measurement. The intensity of the bonded band shows a general decrease with rise in temperature. All these variations are interpreted as being indicative of the weakening of the hydrogen bond with increase in temperature.
Potassium μ-(trans-Hyponitrito-N,N′-bis{pentacyanocobaltate(III)} and Potassium μ-(Trans-Hyponitrito-O,O′)-Bis{Pentacyanocobaltate(III)}
Authors: Okamura Hiromichi , Miki Eiichi , Mizumachi Kunihiko , Ishimori Tatsujiro
Published: July 2006

K6[Co2(CN)10(N2O2)]·2H2O (orange salt) was prepared by reaction of [Co(NO)(NH3)5]Cl2 with an aqueous solution of potassium cyanide. K6[Co2(CN)10(N2O2)]·4H2O (yellow salt) was obtained by adding an aqueous solution of the orange salt to methanol. On the basis of IR and Raman spectra for their 14NO- and 15NO-salts, and of IR spectra for their gaseous decomposition products, the orange salt is considered to be a linkage isomer of the yellow salt with respect to the trans-hyponitrito bridge. It is presumed that the orange salt is potassium μ-(trans-hyponitrito-N,N′-bis{pentacyanocobaltate(III)}, the yellow salt being potassium μ-(trans-hyponitrito-O,O′)-bis{pentacyanocobaltate(III)}.
Fundamental Research into the Treatment of the Chromic Plating Rinse by Reverse Osmosis
Authors: Masuda Hitoshi , Kamizawa Chiyoshi , Matsuda Masazi , Nakane Takashi , Ohira Tsuyoshi
Published: July 2006

Fundamental research into the treatment of the chromic plating rinse by reverse osmosis were carried out with Loeb-type skinned membranes. The effect of the pH on the transport of chromic acid was quantitatively investigated. With the increase in pH, chromic acid dissociates to form a divalent ion, CrO42−, and the rejection by the membrane increases. For example, the rejection of 0.01 M chromic acid at pH 3 was 83%, while it was 96% at pH 7.25, both at 40 atm. The permeation behavior of additives such as sodium hexafluorosilicate and chromium (III) sulfate was also examined, mainly in connection with their dissociation in the solution. In the case of the concentration of chromic acid, the rejection remained constant up to about 15000 ppm, while the flux decreased considerably with an increase in the concentration.
Transition-metal Complexes of Pyrrole Pigments. XIII. Reduction and Coordination Behaviors of the Cobalt(II) Complexes of 1,19-Disubstituted Tetradehydrocorrins as Demonstrated by the Presence of Various Bases
Authors: Murakami Yukito , Aoyama Yasuhiro
Published: July 2006

The interaction of various bases with the cobalt(II) complexes of 1,19-disubstituted tetradehydrocorrins (Co(II)–TDHC) was investigated. The parent cobalt(II) complexes were shown to undergo ready reduction at the nuclear cobalt(II) with the unsolvated hydroxide ion as well as with bulky triethylamine. A relatively large positive reduction potential of Co(II)–TDHC is responsible for these novel electron transfer reactions. Less hindered amines (B), on the other hand, failed to show such electron transfer reactions with the cobalt(II) complexes and Co(II)–TDHC became the pentacoordinated complex by taking up an amine base in the axial position: Co(II)–TDHC+B\ightleftharpoonsB–Co(II)–TDHC. For the interaction of 4-substituted pyridines with the cobalt(II) complex, the general behavior of the equilibrium constants was interpreted in terms of the amine basicity and the Hammett equation by referring to the corresponding behavior of the porphyrin complexes. The weaker coordination tendency of some aliphatic amines and hindered pyridines toward Co(II)–TDHC was attributed to their electronic and steric effects in the coordination process. The intrinsic correlation between electronic and stereochemical characteristics pertaining to the tetradehydrocorrin skeleton and the nature of nuclear cobalt(II) was discussed on the basis of these observations.
Determination of Oxygen in Zinc Compounds
Authors: Imaeda Kazuo , Kuriki Takeo , Ohsawa Keiko
Published: July 2006

Oxygen in zinc compounds was determined by a modification of the method of Schütze. Oxygen in some zinc compounds such as zinc oxide, zinc acetate and zinc oxalate could not be determined by the usual method. The carrier gas method of adding carbon was employed for the determination of total oxygen. Total oxygen could be determined by the addition of 5 mg of carbon to a sample boat and heating at 1000 °C. The determination was also carried out by the carrier gas method by addition of 2 mg naphthalene. As a result, total oxygen could be determined by the addition of 2 mg of naphthalene.
Preparative Thin-Layer Chromatography of Semi-Xylenol Orange and Xylenol Orange by Development with Solvents Giving Discrete pH Change on the Plate
Authors: Yamada Mutsuo , Fujimoto Masatoshi
Published: July 2006

A new procedure is proposed to obtain pure Semi-Xylenol Orange (SXO) and Xylenol Orange (XO) from ca. 100 mg of synthetic mixture using preparative thin-layer chromatography on cellulose layer ca. 2 mm thick. Development with a composite solvent, 55–60 ml of 1-butanol saturated with 25% aqueous acetic acid-0.6–0.8 ml of 28% aqueous ammonia, forms two discrete zones of different pH values on the layer. The zones favor a sharp separation of polybasic Brønsted acids with structures similar to those of SXO and XO. SXO and XO are in the protonated forms corresponding to the pH values of the given zones. XO is located near the starting line in the lower zone of higher pH and SXO migrates through the layer in the upper part of the same zone. Both SXO and XO constitute the compact and concentrated bands. Each run takes only 3 hr. 18 mg of SXO and 36 mg of XO are obtained as sodium salts from 100 mg of the synthetic mixture.
Mössbauer Studies of the Thermal Decomposition of Tris(2,2′-bipyridine)iron(II) Chloride and the Structures of the Isomers of 2,2′-Bipyridineiron(II) Chloride
Authors: Sato Haruo , Tominaga Takeshi
Published: July 2006

The thermal decomposition of [Fe(bipy)3]Cl2·5H2O in nitrogen was investigated by means of Mössbauer spectroscopy. Two isomers of Fe(bipy)Cl2 were found to occur in the decomposition sequence; one of them appears to be identical with the rose-red form of Fe(bipy)Cl2 prepared by the wet process. The structures of the two isomers were determined on the basis of the Mössbauer spectra, the infrared and Raman spectra, the powder X-ray patterns, and the magnetic moments of these compounds. It has been concluded that tris(2,2′-bipyridine)iron(II) chloride presumably decomposes in the following sequence:

[Fe(bipy)3]Cl2·5H2O→Fe(bipy)2Cl2→orangeFe(bipy)Cl2(monomeric, tetrahedral)→rose-redFe(bipy)Cl2(polymeric, octahedral)→FeCl2
The Chemical Behavior of Low Valence Sulfur Compounds. X. Disproportionation of Thiosulfate, Trithionate, Tetra-thionate and Sulfite under Acidic Conditions
Authors: Mizoguchi Tadaaki , Takei Yoshiaki , Okabe Taijiro
Published: July 2006

The disproportionation of thiosulfate, trithionate, tetrathionate and sulfite in acidic solutions has been studied at relatively high temperatures. Thiosulfate hardly decomposes in the absence of sulfuric acid, even at 150 °C, but decomposes very easily in the presence of sulfuric acid at 70 °C, forming elemental sulfur, tetrathionate and sulfite. Trithionate decomposes to thiosulfate and sulfate at 70 °C, while tetrathionate decomposes only at temperatures above 130 °C after an induction period forming thiosulfate as an intermediate. Sulfite undergoes disproportionation, giving thiosulfate and sulfate at 150 °C, and then elemental sulfur and sulfate accompanied by intermediate formation of tetrathionate. A disproportionation pathway of low valence sulfur oxyacids including thiosulfate, trithionate, tetrathionate and sulfite has been proposed.
X-Ray Diffraction Studies of the Structures of Hydrated Divalent Transition-Metal Ions in Aqueous Solution
Authors: Ohtaki Hitoshi , Yamaguchi Toshio , Maeda Masunobu
Published: July 2006

X-ray scattering measurements have been carried out for concentrated aqueous solutions of divalent transition-metal perchlorates of manganese(II) to zinc(II). The radial distribution curves showed that each central metal ion was octahedrally surrounded by six water molecules at the distances of 2.20 Å for Mn2+–OH2, 2.12 Å for Fe2+–OH2, 2.08 Å for Co2+–OH2, 2.04 Å for Ni2+–OH2, and 2.08 Å for Zn2+–OH2. The results from the radial distribution curves were confirmed by the direct analysis of reduced intensities. Concentrated aqueous solutions of copper(II) and zinc(II) sulfates have also been measured. The bond distances of 1.94 Å for the Cu2+–OH2 (equatorial), 2.38 Å for the Cu2+–OH2 (axial) and 2.08 Å for Zn2+–OH2 were consistent with those obtained for the perchlorate solutions. No evidence for the contact ion pairs of metal and sulfate ions was found by the present X-ray measurements. The bond energies between metal ions including copper ion were discussed by application of the Garrick model with a slight modification.
Elimination and Nucleophilic Substitution on Nitrogen Atom. Reactions of O-Aroyl-N,N-di(p-substituted benzyl)- and O-Aroyl-N-benzoyl-N-benzylhydroxylamines with Various Nucleophiles in Dipolar Aprotic Solvents
Authors: Oae Shigeru , Sakurai Tadamitsu
Published: July 2006

The reactions of the title compounds with various nucleophiles were found to proceed through either elimination or nucleophilic substitution on the nitrogen atom depending on both the structure of the substrate and the nature of nucleophiles used. The effect of substituent and the primary isotope effect (kH⁄kD of 7.6 and 8.1 with NaN3 and LiCl at 30 °C) on the elimination of O-(p-nitrobenzoyl)-N,N-dibenzylhydroxylamine revealed that the reaction is an E2 process involving the rate-determining proton abstraction by base and proceeds via an ionic transition state of an ideal concerted type. Nucleophilic substitution on the trivalent nitrogen atom has been inferred for the reactions with such nucleophiles as diethyl sulfide, p-toluenethiol and sodium cyanide on the basis of product distribution.
Role of Amine in Arylation of Ethylene with Iodobenzene Catalyzed by Rhodium Trichloride
Authors: Mori Kunio , Mizoroki Tsutomu , Ozaki Atsumu
Published: July 2006

Rhodium trichloride effectively catalyzes the arylation of ethylene with iodobenzene in the presence of an amine to give styrene, although neither rhodium-powder nor chlorotris(triphenylphosphine)rhodium(I) is effective. The efficacy of the amine in increasing the yield of styrene is remarkable with tertiary and secondary amines but negligible with a primary amine. The difference among these amines in their interaction with rhodium trichloride is explained by their steric hindrance based on the isolation of the Rh(III)–amine complex only with primary amine.
Synthesis of 2,5-Diaryltetrazoles from N-Phenylsulfonylbenzhydrazidoyl Chlorides and Arylhydrazines
Authors: Ito Suketaka , Tanaka Yumo , Kakehi Akikazu
Published: July 2006

A new synthesis of 2,5-diaryltetrazoles is given by the reaction of N-phenylsulfonylbenzhydrazidoyl chlorides with arylhydrazines and the action of potassium carbonate on the intermediate product formed in the initial reaction. Thirty tetrazoles carrying H, CH3, Cl, Br, or NO2 as the para-substituent of the 2-phenyl group, and H, CH3, Cl, CH3O, CN, or NO2 as that of the 5-phenyl group, were synthesized in 70–16% yields, respectively. The reaction may proceed via the concerted elimination of benzenesulfinate ion from the intermediate 1,3-diaryl-5-phenylsulfonylformazanide anion taking a quasi-aromatic configuration.
Reactions of Dihydridotetrakis(tertiary phosphine)ruthenium(II) Complexes with Carbon Dioxide, Carbon Bisulfide and Sulfur Dioxide
Authors: Komiya Sanshiro , Yamamoto Akio
Published: July 2006

Carbon dioxide reacts with RuH2(PPh3)4 to give its insertion product, hydridoformatotris(triphenylphosphine)ruthenium(II). The reversibility of the CO2 insertion has been demonstrated. Insertion products of carbon disulfide and adducts of sulfur dioxide with ruthenium also have been obtained by the reactions of carbon disulfide and sulfur dioxide with various ruthenium dihydride complexes, RuH2L4 (L=PPh3, PPh2H, PPh2Me, PPhMe2). These compounds were characterized by IR and NMR spectroscopy, elemental analysis and chemical reactions.
Branched-chain Sugars V. Stereoselective Synthesis of 3-C- and 5-C-Methyl-d-glucoses, and 5-C-Methyl-l-idose Derivatives
Authors: Funabashi Masuo , Sato Haruo , Yoshimura Juji
Published: July 2006

The title compounds were prepared stereoselectively from 1,2: 5,6-di-O-isopropylidene-3-C-methylene-α-d-ribo-hexofuranose (1) and 3-O-benzyl-1,2-O-isopropylidene-5-C-methylene-6-O-trityl-α-d-xylo-hexofuranose (5b) by the successive epoxidation and reduction, and from 3-O-benzyl-1,2-O-isopropylidene-6-O-trityl-α-d-xylo-hexofuranos-5-ulose (5a) by the Grignard reaction, respectively.
pH-Dependence of Spectral Sensitization at Semiconductor Electrodes
Authors: Watanabe Tadashi , Fujishima Akira , Tatsuoki Osamu , Honda Ken-ichi
Published: July 2006

For an interpretation of the pH-dependence of the sensitized photocurrent at semiconductor electrodes, measurements have been carried out on n-type TiO2 and CdS single crystal electrodes. As sensitizing dyes, rhodamine B and 3,3′-diethylthiacarbocyanine iodide which remain stable in a sufficiently wide pH range were used. It has been found that the logarithm of the sensitized photocurrent at TiO2 electrode depends linearly on the pH of the electrolyte solution, whereas the sensitized photocurrent shows practically no pH-dependence at CdS electrode. These observations have been accounted for on the basis of the different pH-dependence of flatband potentials of these semiconductor electrodes.
The Sensitization of Rare Earth Ion Luminescence in Dilute Solutions by [1]Benzopyrano[3,4-c]pyridine-4,5(3H)-dione Derivatives
Authors: Fujimoto Akira , Sakurai Akio , Iwase Eiichi
Published: July 2006

Luminescence spectra and lifetimes are presented for the rare earth ions sensitized by [1]benzopyrano[3,4-c]pyridine-4,5(3H)-dione derivatives in dilute solutions. It is to be noted that, among the benzopyranopyridine derivatives investigated, 2-phenyl-[1]benzopyrano[3,4-c]pyridine-4,5(3H)-dione brings about the most efficient sensitization for the luminescence of europium and terbium ions. Some discussions are made of the energy-transfer processes from these excited benzopyranopyridine derivatives to terbium ions.
The Molecular Motion of Phenyl Groups in Toluene, Diphenylmethane and Triphenylmethane in Solutions of Carbon Tetrachloride by Raman Line Shape Analysis
Authors: Nomura Hiroyasu , Miyahara Yutaka , Koda Shinobu
Published: July 2006

The reorientational correlation times of phenyl groups in the molecules of toluene, diphenylmethane, and triphenylmethane in carbon tetrachloride solutions were measured by the Raman-line-shape analysis. The reorientational relaxation times of the phenyl groups obtained increased in this order: toluene<diphenylmethane<triphenylmethane as a result of the increase in the mutual interaction among phenyl groups themselves in the molecule.
Heterogeneous Asymmetric Hydrogenation of Benzil Using Bis(dimethylglyoximato)cobalt Complexes as Catalysts
Authors: Fujikoshi Hideaki , Nakajima Riichiro , Hara Tadashi
Published: July 2006

The asymmetric hydrogenation of benzil in the heterogeneous system was found to proceed not only in the presence of quinine soluble in benzene phase, but also of an optically active amino or ascorbic acids soluble in aqueous phase.
The Reaction of Organic gem-Dihalides with Zerovalent Transition Metal Complexes. An Approach to Organic Synthesis
Authors: Furukawa Junji , Matsumura Akira , Matsuoka Yoshihito , Kiji Jitsuo
Published: July 2006

The reaction of ω,ω-dibromoacetophenone with Ni(COD)2 (COD=1,5-cyclooctadiene), Fe(CO)5, or Co2(CO)8 gave trans-1,2,3-tribenzoylcyclopropane, while the reaction with Pd[P(C6H5)3]4 or Ni[P(OC2H5)3]4 gave trans-1,2-dibenzoylethylene. Phenyl isocyanide dichloride was dechlorinated by metal carbonyls to give phenyl isocyanidesubstituted metal carbonyls.
ESR Study of Cationic Radicals in Aromatic Compound–Cu–AlCl3 Systems
Authors: Imamura Sei-ichiro , Hamanoue Kumao , Fukuda Seiji , Teranishi Hiroshi , Watanabe Yoshihisa
Published: July 2006

The electron spin resonance spectra of several aromatic compound–Cu–AlCl3 systems were observed. When benzene, toluene, and ethylbenzene were used as the aromatic compounds, a singlet with a g-value of 2.003 was obtained. In the case of the o-, m-, and p-xylene systems, spectra with well-resolved hfs’s resulted. It was suggested that cationic radicals were formed by a transfer of an electron from the benzene ring to Cu(II)–AlCl3.
Picosecond Flash Spectroscopy of Solvent-Induced Intramolecular Electron Transfer in the Excited 9,9′-Bianthryl
Authors: Nakashima Nobuaki , Murakawa Masamichi , Mataga Noboru
Published: July 2006

Sn←S1 absorption spectra of 9,9′-bianthryl in the visible and near infrared regions have been measured by means of picosecond flash spectroscopy. The Sn←S1 spectra in hexane measured at 500 ps after the exciting pulse were similar to those of anthracene while those in acetone were similar to the superposition of spectra of anthracene anion and cation. The results of the Sn←S1 spectral measurements together with those of the solvent effects upon the fluorescence yield and lifetime indicate an intramolecular electron transfer induced by the interaction with polar solvents in the excited state of 9,9′-bianthryl.
The Two-step Collapse of Mixed Monolayers of Cholesterol and Its Esters
Authors: Nakagaki Masayuki , Handa Tetsurou
Published: July 2006

Mixed monolayers of two insoluble components out of cholesterol and its acetate and propionate were spread on a dilute aqueous solution of disodium hexadecyl phosphate. The curves of the surface pressure against the molecular area were found to have two kink points, collapse points, although the curves of each component, and also that of the “concollapse” mixture, had only one collapse point. The diagram showing the relation between these two collapse pressures and the composition was entirely analogous to the phase diagrams of bulk mixtures which have an eutectic point. It has, therefore, been concluded that the mixed monolayer of two mutually immisible substances undergoes a two-step collapse. At the lower collapse point, one of the two components, i, starts separating from the monolayer. The lower collapse pressure, FCl′ varies with the mole fraction, Xi, according to FCl′=Fol′−(kT⁄Aol)lnXi. At the higher collapse point, the other component starts separating as well. Upon further compression, the surface pressure remains unchanged at the higher collapse pressure, which is equal to the equilibrium-spreading pressure and is independent of the composition.
Photoemission from Polycyclic Aromatic Crystals in the Vacuum-Ultraviolet Region. V. Photoelectron Spectroscopy by the Rare Gas Resonance Lines and Vacuum-Ultraviolet Absorption Spectra
Authors: Seki Kazuhiko , Hirooka Tomohiko , Kamura Yusuke , Inokuchi Hiroo
Published: July 2006

The photoelectron spectra (energy distribution curves, ECDs) of naphthacene, pentacene, perylene, coronene, and p-terphenyl by He(I), Ne(I), and Ar(I) resonance lines (photon energies, 11.62–21.22 eV) and the absorption spectra of naphthacene, pentacene, perylene, and coronene at 4–9.5 eV are measured for evaporated polycrystal films. The absorption spectra are compared with the spectral dependence of the quantum yield (SDQY) of photoemission. A similar comparison is also made for p-terphenyl and anthracene. The origin of the structures in SDQY curves is discussed. The analysis reveals that: (1) the MOs of a molecule are preserved even in crystals; (2) the large peak at a low kinetic energy of the photoelectron spectra is due to secondary electrons, and (3) at least for naphthacene, pentacene, and coronene, autoionization takes place with a considerable efficiency.