bluuebunny/crossref_metadata_2025 huggingface dataset:
Sulfur K-Edge Absorption Spectra of Na2SO4, Na2SO3, Na2S2O3, and Na2S2Ox (x=5–8)
Authors: Sekiyama Hideo , Kosugi Nobuhiro , Kuroda Haruo , Ohta Toshiaki
Published: July 2006

X-Ray absorption spectra of the sulfur K-edges of SO42−, SO32−, S2O32−, and S2Ox2− (x=5–8) were measured with synchrotron radiation. The spectra show similarly strong absorption bands which originate in bound-state transitions to antibonding 3p-type orbitals and in shape resonances related to 3d-type orbitals. The K-edge spectrum for the terminal sulfur atom in S2O32−, however, shows only a bound-state transition. Differences in chemical environments and bonding around the X-ray absorbing atoms are discussed to interpret the spectra.
Solvent Effect on the Liquid–Liquid Partition Coefficients of Dimethyldithiocarbamic Acid and Its Copper(II) Chelate
Authors: Imura Hisanori , Matsumora Satoru , Suzuki Nobuo
Published: July 2006

Partition coefficients of dimethyldithiocarbamic acid and its copper(II) chelate have been determined in various organic solvents −0.10 mol dm−3 aqueous perchlorate solution systems at 25 °C. The effects of inert organic solvents are explained with the aid of the regular solution theory. Also, a linear free-energy relationship between the partition coefficient of the copper(II) chelate and that of the reagent is demonstrated. The partition coefficient of the copper(II) chelate is compared with that of bis(2,4-pentanedionato)copper(II) and various factors governing the partition coefficients of these chelates are discussed with the aid of the scaled particle theory.
Amijitrienol and 14-Deoxyisoamijiol, Two New Diterpenoids from the Brown Seaweed Dictyota linearis
Authors: Ochi Masamitsu , Asao Kazuhiko , Kotsuki Hiyoshizo , Miura Iwao , Shibata Kozo
Published: July 2006

The structures of amijitrienol and 14-deoxyisoamijiol, two new diterpenoids isolated from the brown seaweed Dictyota linearis, have been established as 1 and 2 on the basis of spectral and chemical evidence.
An Improved Synthesis of N-Trifluoroacetyl-l-daunosamine
Authors: Kimura Yoshikazu , Matsumoto Teruyo , Suzuki Michiyo , Terashima Shiro
Published: July 2006

A process which can afford a large quantity of the title compound was explored by modifying the Horton’s original route. The developed process features highly stereoselective reduction of the oxime with sodium dihydrobis(2-methoxyethanolato)aluminate(1-) and efficient dehydrobromination with 1,8-diazabicyclo[5.4.0]undec-7-ene.
Reactions of Sodium Hydrogentelluride with α-Azido Ketones and α-Azido Bromides
Authors: Suzuki Hitomi , Kawaguchi Takashi , Takaoka Koji
Published: July 2006

When treated with sodium hydrogentelluride in ethanol at room temperature, α-azido ketones are easily converted to pyrazines via the self-condensation of initially formed α-amino ketones followed by aerobic oxidation during work-up. On a similar treatment, activated α-azido bromide such as 1,2-diphenyl-1-azido-2-bromoethane suffers E2-type β-elimination to give the corresponding olefin as the sole product, while ordinary α-azido bromides afford complicated mixtures containing amino and olefinic compounds among other products.
Isopropylidenation of Raffinose
Authors: Otake Toshiki , Tsukahara Junko
Published: July 2006

A reaction of raffinose with an excess amount of 2,2-dimethoxypropane and p-toluenesulfonic acid as a catalyst in N,N′-dimethylformamide, followed by acetylation, gave seven kinds of mono-, di, or tri-O-isopropylideneraffinose peracetates with at least five kinds of minor products. A reaction of raffinose with a limited amount of 2,2-dimethoxypropane gave a new isopropylidene derivative with some of the derivatives described above. The isopropylidenation occurred at 1′,2-, 2,3-, 2″,3″-, 3,4-, 3″,4″-, and 4″,6″-positions. The structures of these compounds were established by 1H and 13C NMR analyses.
The Electrical Properties of La2−xSrxNiO4 (0≤x≤1)
Authors: Ishikawa Kenji , Kondo Shin-ichi , Suzuki Yuichi , Takayama Shin-ichi , Shimada Kazuhiko , Suzuki Yasuo
Published: July 2006

The electrical resistivities and Seebeck coefficients of mixed oxides, La2−xSrxNiO4, have been determined under an He atmosphere at 77.4–673.2 K. It has been shown that the temperature dependences of the Seebeck coefficients of the oxides were fairly well approximated by this equation: S=AT+B+C⁄T, where T is the thermodynamic temperature. The coefficients of the equation, A, B, and C, were given by the least-squares method. The metal-semiconductor ratios {α≡(C⁄T)⁄(AT+C⁄T)} were given to characterize the thermoelectrical properties of La2−xSrxNiO4. The maximal activation energies (Ea(resis.) and Ea(Seebeck)) and the maximal metal-semiconductor ratio (α) were obtained with the strontium concentration of La2−xSrxNiO4 at x=0.5. The lattice distortion of the oxides is responsible for the maxima of the activation energies and of the metal-semiconductor ratio at x=0.5.
Spectrophotometric Determination of Micro Amounts of Thiocyanate via Permanganate Reaction
Authors: Miura Yasuyuki , Koh Tomozo
Published: July 2006

A method has been developed for the determination of micro amounts of thiocyanate. It is based on the reaction of thiocyanate with a given amount of permanganate as an oxidizing agent in a dilute sulfuric acid medium and on the spectrophotometric measurement of iodine as triiodide, which is formed by the oxidation of iodide with an excess of permanganate for its reaction with thiocyanate. The conditions for the thiocyanate to be quantitatively oxidized were established by varying the temperature, reaction time, and amounts of sulfuric acid and permanganate. The present method can be successfully applied to the determination of thiocyanate in the range from 7×10−7 to 4×10−5 mol dm−3 (0.4–23.2 μg SCN− in 10 cm3). In eleven determinations for 10-cm3 sample solutions containing 0.250 μmol of thiocyanate, the present method gave a mean value of 0.251 μmol, with a standard deviation of 0.0022 μmol and a relative standard deviation of 0.88%. Chloride, bromide, iodide, and cyanide did not interfere with the determination of 14.5 μg of thiocyanate in the presence of 1000 μg, 500 μg, 100 μg and 50 μg, respectively.
Oxidation of Alcohols and Ethers Using Sodium Bromate–Hydrobromic Acid System
Authors: Kajigaeshi Shoji , Nakagawa Takashi , Nagasaki Noritaka , Yamasaki Hiromichi , Fujisaki Shizuo
Published: July 2006

Reaction of primary alcohols or simple ethers, α,ω-diols or cyclic ethers, and secondary alcohols with sodium bromate in the presence of catalytic amount of hydrobromic acid under mild conditions gave dimeric esters, lactones, and ketones in fairly good yields, respectively.
Hydration of the Oxyethylene Chain. Hypersonic Velocities in Aqueous Solutions of α-Methyl-ω-methoxyoligo(oxyethylene)s and α-Methyl-ω-hydroxyoligo(oxyethylene)s as Studied by Brillouin Scattering
Authors: Matsuura Hiroatsu , Fukuhara Koichi
Published: July 2006

Hydration of the oxyethylene chain was studied by a Brillouin-scattering method; hypersonic velocities in aqueous solutions of CH3(OCH2CH2)mOCH3 with m=1–4 and CH3(OCH2CH2)mOH with m=2 and 3 were measured. The concentration of the solution, at which the sound velocity gave a maximum value, led to the number of water molecules, at the highest hydration, per ether linkage in the oxyethylene chain. The experimental results showed that 1.8 water molecules take part in the hydration of each –CH2OCH2– group and that the number of the water molecules is virtually constant independently of the oxyethylene-chain length as far as the number of the oxyethylene units is limited up to four. These findings indicate that a sort of hydration complex of approximately 1 –OCH2CH2–:2 H2O is formed in the aqueous solution. It is suggested that the stabilization of the gauche conformation for the OCH2–CH2O group in aqueous solution, as evidenced by Raman-spectroscopic observations, is promoted greatly by the hydrogen bond of water molecules which are bridged between the adjacent ether oxygens in the oxyethylene chain.
The Hydrogenation of Benzil Catalyzed by Cobalt(II) Dimethylglyoxime Complex
Authors: Mita Keisuke
Published: July 2006

Kinetic studies on the catalytic hydrogenation of benzil to benzoin by bis(dimethylglyoximato)cobalt(II), Co(Hdmg)2, were carried out by varying the concentration of Co(Hdmg)2 and pyridine. The initial rate of the hydrogenation reaction was first order with respect to the overall cobalt concentration at a constant overall pyridine concentration. On the other hand, the rate passed through a peak as the overall pyridine concentration was increased at a constant overall cobalt concentration. The peak was observed at [py]T=130 mmol dm−3, where the square bracket denotes the concentration in the liquid phase. These results show that the initial reaction rate, Vin, can be expressed by the following rate equation,

V in=k[Co(Hdmg)2]\frac58[py]T1+58[py]T,

where, k=1.1 min−1.
Hydrates of Organic Compounds. X. The Formation of Clathrate Hydrates of Tetrabutylammonium Alkanesulfonates
Authors: Nakayama Haruo , Usui Hideyuki
Published: July 2006

The solid–liquid phase diagrams of binary mixtures of water with tetrabutylammonium alkanesulfonate (n-C4H9)4NO3SR(R=CH3–C5H11) and with tetrabutylammonium benzenesulfonate were examined in order to confirm the formation of clathrate-like hydrates. It has been found that (1) all the sulfonates examined can form clathrate-like hydrates with hydration numbers either around 30 or around 39; (2) these hydrates can be classified into three groups I, II, and III on the basis of the hydration numbers and melting points just as in the case of a series of tetrabutylammonium carboxylate hydrates; and (3) generally, the melting points of these sulfonate hydrates are lower than those of tetrabutylammonium carboxylate hydrates. The formation of clathrate-like hydrates of tetrabutylammonium hydrogensulfite and of tetrabutylammonium sulfite has also been reported and is discussed in an appendix.
Absorption Spectra of Tetrahedral Co(II) in Single Crystals of [N(CH3)4]2[CoX4] (X=Cl,Br)
Authors: Kojima Kazuo , Matsuda Jiro
Published: July 2006

The optical absorption spectra of single crystals of [N(CH3)4]2[CoCl4] and [N(CH3)4]2[CoBr4] have been measured over the range of 4000–33000 cm−1 at the temperature of liquid nitrogen and at room temperature. The spectra have been analyzed using the crystal-field theory which includes spin-orbit coupling. Some discussion of the Racah parameter B and of the 4T1(4F) and 4T1(4P) states is presented.
The Separation and Concentration of Gallium(III) and/or Indium(III) Using Polystyrene Resins Functionalized with Complexane-Type Ligands
Authors: Suzuki Toshishige M , Yokoyama Toshiro , Matsunaga Hideyuki , Kimura Tetsuo
Published: July 2006

Macroreticular styrene-divinylbenzene copolymers functionalized with iminodiacetic acid and diethylenetriamine-N,N,N″,N″-tetraacetic acid have been examined in order to apply them to the selective recovery of gallium(III) and/or indium(III) from acidic solutions. The equilibrium adsorption capacities, distribution coefficients, and metal-adsorption rates of the polymer resins for Group IIIb ions and other common metal ions have been studied. The selectivity sequence of the present resins are as follows: Fe(III)>In(III)>Ga(III)\simeqCu(II)>Zn(II)>Al(III). The selective recovery of In(III) and/or Ga(III) from acidic solutions has been demonstrated using a column of the present resins.
2-Allylisourea as an Effective Agent for Direct α-Allylation of Ketone and Aldehyde Assisted by Palladium(0) under Neutral Conditions
Authors: Inoue Yoshio , Toyofuku Masanori , Taguchi Masaaki , Okada Shin-ichi , Hashimoto Harukichi
Published: July 2006

Direct α-allylation of a variety of ketones and aldehydes with 2-allylisourea took place in the presence of a catalytic amount of a palladium(0) complex under neutral and mild conditions. Scope and limitations of this novel method have been investigated.
Replacement of the Activated Nitro Group by a Phenylthio Group
Authors: Miyake Hideyoshi , Yamamura Kimiaki
Published: July 2006

The nitro group, activated by a carbonyl group, alkoxycarbonyl group or a phenyl group, can be replaced by a phenylthio group in the reaction with benzenethiol or its potassium salt. This reaction proceeds in the electron transfer mechanism, and is applicable to the general syntheses of α-phenylthio ketones, α-phenylthio carboxylic esters and α-phenylthio alkylbenzenes from primary nitro compounds.
Electron-Transfer-Initiated Photoreactions of 1-Methyl-2-phenyl-1-pyrrolinium Perchlorate with α-Heteroatom-Substituted Alkanoate Anions
Authors: Kurauchi Yoshiaki , Nobuhara Hideo , Ohga Kazuya
Published: July 2006

The irradiation of aqueous solutions of 1-methyl-2-phenyl-1-pyrrolinium perchlorate (1) in the presence of α-hydroxyalkanoate anions led to the formation of 2-(hydroxyalkyl)pyrrolidine adducts and a reduction product, 1-methyl-2-phenylpyrrolidine. Mechanistic studies demonstrated that photoaddition reactions were induced by one-electron transfers from the carboxylato groups of alkanoates to the excited singlet state of 1 (1S1), followed by an efficient decarboxylation. Furthermore, the photoreaction of 1 with ethoxyacetate was found to give a 2-(ethoxymethyl)pyrrolidine adduct in preference to the reduction product. For photoreactions with 2-mercaptopropionate and α-amino acids, the reduction product was detected. N-Acetylglycinate gave a 2-(acetylaminomethyl)pyrrolidine adduct in fairly high yield (80%). The features of these photoreactions with α-heteroatom-substituted alkanoates are discussed in terms of fluorescence-quenching efficiencies and the properties of radicals formed through electron transfers to 1S1.
Photoionization Threshold Energies of Amine Solutions Studied by Photoelectron Emission by Solution
Authors: Watanabe Iwao , Maya Keiichi , Yabuhara Yoshiki , Ikeda Shigero
Published: July 2006

The threshold energies Et of photoelectron emission by solutions (PEES) were determined for several butylamines in acetonitrile and water. The correlations between Et and gas-phase ionization potential Ip and oxidation potential Eox were found to be linear. The difference between Et and Ip originates from the electronic polarization energy of solvent molecules and the polarization energy was found to be inversely proportional to the solvation radius in accordance with the Born solvation free energy model. The Et values were also compared with Eox to discuss the reorientation relaxation of solvent molecules in the electron transfer process. The selective coverage of aqueous solution surface with amine molecule was indicated by the PEES technique.
Generation of the Selenonium Ylide by the Carbenic Reaction. Formation of Cyclopropane Derivatives via Selenonium Ylide
Authors: Ibata Toshikazu , Kashiuchi Makoto
Published: July 2006

The Cu(acac)2-catalyzed decomposition of α-diazoacetophenones in the presence of bis(p-methoxyphenyl) selenide (3) did not give the corresponding selenonium ylide but gave r-1,c-2,t-3-tribenzoylcyclopropanes through the successive reaction of the intermediary selenonium ylide. On the other hand, the reaction of diazodimedone with 3 gave bis(p-methoxyphenyl)selenonium 4,4-dimethyl-2,6-dioxocyclohexylide.
Kinetic Studies of Fast Equilibrium by Means of High-Performance Liquid Chromatography. XIII. Separation of Rotamers of N-Alkyl-Substituted Amides
Authors: Moriyasu Masataka , Kato Atsushi , Hashimoto Yohei
Published: July 2006

Rotamers of N-alkyl-substituted amides have been separated by means of high-performance liquid chromatography(HPLC) at low column temperatures. The ratios of the E-rotamers have been found to increase in the following order: propionamides<acetamides<formamides.
Ion-Chromatographic Determination of Valproic Acid
Authors: Itoh Hisaaki , Shinbori Yoshio , Tamura Norihiro
Published: July 2006

A new direct chromatographic assay method of valproic acid (2-propylpentanoic acid) using a carbonic acid solution as the eluent and conductivity detection was developed and applied to its determination in Depakene tablets and human plasma. The analytical recovery and the coefficients of variation of the method obtained by the use of drug-free plasma samples spiked with various amounts of valproic acid were ranged from 96.5 to 104% and from 3.2% at 12.4μg cm−3 to 0.8% at 124μg cm−3, respectively. No interference from the plasma constituents or from other anticonvulsants was observed. The procedure is simple, fast, specific, and precise. The plasma levels of valproic acid obtained from patients receiving sodium valproate together with other anticonvulsants are indicated.
A General Synthetic Method of Chiral 2-Arylalkanoic Esters via Thermal 1,2-Rearrangement
Authors: Honda Yutaka , Ori Aiichiro , Tsuchihashi Gen-ichi
Published: July 2006

(S)-1-Aryl-2-sulfonyloxy-1-alkanone acetals, prepared from natural ethyl (S)-lactate or (S)-valine (chiral sources) by the use of a Grignard reaction, were rearranged under hydrolytic conditions in the presence of a base to give (S)-2-arylalkanoic esters which, in general, showed much higher pharmacological activities than their antipodes.
Free Radical Addition of 2-Bromoalkanoic Acids to Alkenes
Authors: Nakano Taichi , Kayama Mikio , Nagai Yoichiro
Published: July 2006

The benzoyl peroxide-catalyzed reaction of 2-bromoalkanoic acids such as bromoacetic, 2-bromopropionic, and 2-bromobutyric acid with 1-alkenes was found to proceed through the addition of the C–Br bond across the double bond followed by cyclization affording 4-alkanolides in good yields.
The Transformation of Cyclic Alcohols into Cyclic Acetals through a New Oxygen Atom Insertion by Photolysis in the Presence of Lead Tetraacetate and Iodine
Authors: Suginome Hiroshi , Washiyama Haruka , Yamada Shinji
Published: July 2006

Photolysis of the hypoiodites of steroidal cyclic homoallyl alcohols such as cholesterol and of cyclic alcohols such as 5α-androstan-17β-ol generated in situ in benzene with three molar equivalents each of lead tetraacetate and iodine was found generally to result in the unprecedented formation of corresponding lactol acetates in yields up to 66%. The lactol acetates are readily hydrolysed to lactols in most cases during their isolation and lactols are isolated products. Thus, cholesterol gave 4-oxa-A-homocholest-5-en-3-ol and its acetate in a 53% yield. The products differ considerably from those reported by us after the photolysis of the hypoiodites by using mercury(II) oxide and iodine as the reagents for generating the hypoiodites; they also differ from those in the oxidation of the steroidal alcohols with lead tetraacetate alone. The photolysis of the hypoiodite of 2,2-dimethyl-5β-cholestan-3-ol was found to lead to the formation of an anomalous lactol, 2α-iodomethyl-2β-methyl-4-oxa-A-homo-5α-cholestan-4ξ-ol together with normal lactol. We discuss the paths of the formation of the lactol acetates involving β-scission of the alkoxyl radicals. A new process was found in the photolysis of 2-indanol hypoiodite in the presence of lead tetraacetate and iodine. Our previously suggested pathways to the formation of 3α,5-epoxy-6-iodo-4-oxa-A-homo-5α-cholestanes and 3-formyloxy-2-iodo-2,3-seco-A-norcholest-5-ene in the photolysis of cholesterol hypoiodite in the presence of mercury(II) oxide and iodine were supported by the results of the photolysis of 4-oxa-A-homocholest-5-en-3-ol hypoiodite in the presence of mercury(II) oxide and iodine.
Stereoselective Synthesis of Octadecapolyenoic Esters as an Insecticide
Authors: Tsuboi Sadao , Wu Xue Han , Maeda Seiji , Ono Shinichiro , Kuroda Akihisa , Kawazu Kazuyoshi , Takeda Akira
Published: July 2006

Octadecapolyenoic acid derivatives such as (±)-t-butyl coriolate, α-eleostearic acid, t-butyl punicate, and t-butyl (9Z,11E)-13-hydroxy-9,11-octadecadien-15-ynoate were synthesized starting from oleic acid with high stereoselectivity and their insecticidal activity was examined.
New Liquid Crystalline Homologous Series Exhibiting the Smectic C Phase
Authors: Sakagami Sakumitsu
Published: July 2006

A liguid crystalline homologous series of N-[4-(4-alkoxybenzoyloxy)benzylidene]-4-butylanilines and their hydroxyl derivatives at the 2-position were synthesized, and then the liquid-crystalline-phase transitions were determined using a differential scanning calorimeter and a polarizing microscope. All of the members exhibit a nematic phase, and a smectic C phase can be observed for the homologues with a relatively long alkoxyl chain.
Kinetics of the Solubilization of Pinacyanol Chloride into a Complex between Bovine Serum Albumin and Sodium Dodecyl Sulfate
Authors: Takeda Kunio , Ohtawa Tohru , Hachiya Kazuaki , Aoki Koichiro
Published: July 2006

The stopped-flow method was applied to the solubilization of pinacyanol chloride into a complex formed by bovine serum albumin and sodium dodecyl sulfate. The rate constant of the solubilization became larger with the step-by-step formation of the complex and finally attained values compatible with those for the pure surfactant micelle.
Cobalt(III) Complexes with [N6−nXn]-Type Ligands. VI. The Preparation and Properties of Tetraammine(salicylamidato)cobalt(III) Complexes
Authors: Yamamoto Yoshihisa , Shinya Noriko
Published: July 2006

Tetraammine(salicylamidato)cobalt(III) complexes, (Remark: Graphics omitted.)) (X: Cl, NO3 and picrate), have been isolated and characterized by means of analytical, spectroscopic, and magnetic methods. The bond between the cobalt atom and the chelated ligand in the complex is expressed in the form of –\barO–Co–\barN–. The properties of the title complexes are intermediate between those of the tetraammine(salicylideneaminato)cobalt(III) complex, which has the –\barO–Co–N– bond, and the tetraammine(salicylato)cobalt(III) complex, which has the –\barO–Co–\barO– bond.
The Syntheses and the X-Ray Crystal Structure of Tetramethylammonium Tetrakis- and Tris(thiocyanato)cadmates(II), [(CH3)4N]2[Cd(SCN)4] and [(CH3)4N][Cd(SCN)3]
Authors: Kuniyasu Yasumitsu , Suzuki Yasuo , Taniguchi Masahiro , Ouchi Akira
Published: July 2006

The crystal and molecular structure of the two new thiocyanatocadmate(II) complexes indicated in the title were determined by the single-crystal X-ray-diffraction technique. [(CH3)4N]2[Cd(SCN)4] is tri-clinic, with a space group of P\bar1; a=7.300(2), b=13.019(4), c=5.8920(9) Å, α=96.32(2), β=93.080(18), γ=104.63(2)°, and Z=1, while [(CH3)4N][Cd(SCN)3] is orthorhombic with a space group of Pna21; a=10.506(3), b=13.797(5), c=9.4506(18) Å, Z=4. In both complexes, the cadmium atom is in an octahedral geometry. In 1, the metal atom is at the center of symmetry, and respective pairs of side-by-side metal atoms are bridged by two thiocyanate (SCN) ions, where one SCN ion is S-coordinated and the other is N-coordinated to the same-side metal atom. Also bonded with two nitrogen atoms of unidentate SCN ions, the metal atom is 4N2S-hexa-coordinated, and they line up along the c-axis in a polymeric form. In 2, respective pairs of side-by-side metal atoms are bridged by three SCN ions, two of those SCN ions being S-coordinated, and one N-coordinated, to the same-side metal atom; each metal atom is 3S3N-hexa-coordinated, and the chain of the polymeric complex lines up along the a-axis. The tetramethylammonium ions bond with the polymeric complex only by the ionic bonding. The final R values obtained are 1=0.039 and 2=0.050.
Thermal Condensation in Solid State of N-Hydroxyalkyl-2-imidazolidinone
Authors: Shimasaki Choichiro , Kanayama Ryosei , Yoshida Hiroaki , Yugamidani Makoto
Published: July 2006

N-(1-Hydroxyalkyl)-2-imidazolidinones (1) were prepared by a reaction of 2-imidazolidinone with form-, acet-, propion-, and butyraldehyde. In all of these reactions, 1 were unstable and moisture-sensitive substances. The pyrolysis reaction of 1 was found to be a thermal decomposition via a condensation reaction stage after a molten state. The condensation stage obeyed 1/2- and the first-order kinetics. The kinetic data regarding the condensation reaction were evaluated by analyses of the dependences of the area of isothermal DSC curves upon the reaction time. It may be concluded that the difference provided by the reaction order and the activation parameters were caused by the number of the hydrogen atoms on the β-carbon atom adjacent to the carbon attacked the hydroxyl group of side chain in 1. In the decomposition by electron impact of 1 and dimer of 1, the cleavage of the five-membered ring which corresponded to the molecular-ion peak for 2-imidazolidinone (m⁄z 86) was considered to take place after a successive cleavage of the side chain. On the basis of both kinetic studies and ESR or Mass spectral observations, the dimerization mechanism is fully discussed.
Highly Regioselective α-Addition of Alkynyl and Alkenyl Grignard Reagents to 1-Alkoxycarbonylpyridinium Salts and Its Application to Synthesis of 1-Azabicycloalkanes and (±)-Solenopsin A
Authors: Yamaguchi Ryohei , Nakazono Yutaka , Matsuki Toshitsugu , Hata Ei-ichiro , Kawanisi Mituyosi
Published: July 2006

Nucleophilic addition of a variety of alkynyl and alkenyl Grignard reagents to 1-methoxycarbonylpyridinium chloride takes place at the α-position in a highly regioselective manner to give 2-substituted 1-methoxycarbonyl-1,2-dihydropyridines exclusively, while, with alkyl Grignard reagents, a lack of the regioselectivity is observed. These results may be explained by the HSAB principle. The high α-regioselectivity is preserved in the cases of 2-substituted pyridines as well, giving 2,6-disubstituted 1,2-dihydropyridines exclusively, which can be transformed stereoselectively into cis- and trans-2,6-dialkylated piperidines. These highly regioselective α-alkynylations of 1-methoxycarbonylpyridinium salts are exploited in synthesis of 1-azabicycloalkanes as well as (±)-solenopsin A.
Comparison of Stability Constants of Alkaline Earth Chlorides between Conductometric and Potentiometric Studies
Authors: Doe Hidekazu , Wakamiya Kenichi , Kitagawa Toyokichi
Published: July 2006

The stability constants of alkaline-earth metal chlorides, MCl+ (M2+=Ca, Sr, Ba), were determined by conductometric and potentiometric measurements in methanol. The conductometric study was made at 5, 15, 25, 35, and 45°C; the potentiometric study was at 25°C. The formation of MCl2 was neglected in the conductometric study, while in the potentiometric study it was taken into account, though it was too slight to determine a reliable value of the stability constant of MCl2. The stability constants of MCl+, K1, determined by conductometric measurements were compared with the previous conductometric results of the same metal(II) perchlorates, K1A. The magnitudes of K1 and K1A increase in the orders Ca \simeqSr<Ba and Ca<Sr<Ba, respectively. K1 is larger than K1A for calcium and strontium, though the K1 and K1A values for barium are similar to each other; that is, the degree of such an increase in K1A is larger than that in K1. Both enthalpy and entropy changes determined by conductometric measurements were positive for all the chlorides and perchlorates. However, the enthalpy changes of the chlorides were 1.2–1.4 times as large as those of the perchlorates. On the other hand, the K1 from potentiometry was smaller for every chloride and also increased more steeply (in the order Ca<Sr<Ba) than that from conductometry. Therefore, the difference of K1 between conductometry and potentiometry decreases in going from Ca to Ba.
Mössbauer Spectroscopic Study on the Mixed-Valence States of 1′,1'″-Dimethyl-, 1′,1'″-Dipentyl-, 1′,1'″-Dihexyl-, and 1′,1'″-Didecylbiferrocenium Triiodide
Authors: Nakashima Satoru , Katada Motomi , Motoyama Izumi , Sano Hirotoshi
Published: July 2006

1′,1'″-Dimethyl-, 1′,1'″-dipentyl-, 1′,1'″-dihexyl-, and 1′,1'″-didecylbiferrocene were synthesized and Mössbauer spectroscopic measurements of their monocation salts were carried out at various temperatures in order to know the mixed-valence states. Effects of alkyl substituent on the valence states of iron atoms in the monocation salts of 1′,1'″-dialkylbiferrocenes are discussed.
The ν8 Infrared Band of Ethylidynephosphine CH3C≡P and Its Perdeuteride CD3C≡P
Authors: Ohno Keiichi , Matsuura Hiroatsu
Published: July 2006

The gas-phase infrared spectra of ethylidynephosphine CH3C≡P and its perdeuteride CD3C≡P were measured in the 50–400 cm−1 region with a resolution of 0.12 cm−1. The molecular constants for the ν8±1 and 2ν80–ν8±1 bands were determined by the P,RQK branch analysis.
Topological Charge Stabilization Rule and Quasi-Aromaticity
Authors: Aihara Jun-ichi
Published: July 2006

Stabilities of the oxocarbon dianions and some quasi-aromatic compounds can be rationalized in terms of Gimarc’s topological charge stabilization rule. The term “quasi-aromatic” is recommended for describing those non-aromatic compounds which behave like aromatics owing to the operation of this rule.
X-Ray Structure of μ-Oxo-μ-sulfido-bis[(cysteinato)oxomolybdate(V)] Complex, Ca[Mo2O3S(SCH2CH(NH2)CO2)2]·3H2O
Authors: Shibahara Takashi , Kuroya Hisao , Matsumoto Keiji , Ooi Shun’ichiro
Published: July 2006

The crystal structure of μ-oxo-μ-sulfido cysteinato Mo(V) dimer, Ca[Mo2O3S(SCH2CH(NH2)CO2)2]·3H2O has been determined from X-ray diffraction data. The structure of the complex anion is similar to those of di-μ-oxo- and di-μ-sulfido- Mo(V) dimers. The trans influence of sulfur atoms is observed.
Reactions of Trimethylsilyl Isothiocyanate with Aldehydes and Acetals. Synthesis of Symmetrically and Unsymmetrically Isothiocyanato-Substituted Ethers
Authors: Nishiyama Kozaburo , Oba Makoto
Published: July 2006

The reactions of trimethylsilyl isothiocyanate (TMSTC) with aldehydes catalyzed by Lewis acid gave α,α′-diisothiocyanato ethers in good to excellent yields. Similarly, unsymmetrical α-isothiocyanato ethers were obtained from the reactions of TMSTC with acetals in appropriate yields.
Improved Synthesis of Dibenzo[a,j]perylene-8,16-dione
Authors: Hirakawa Kiyoichi , Ogiue Eriko , Motoyoshiya Jiro , Kakurai Toshio
Published: July 2006

An improved method for the synthesis of the title compound 1 has been achieved through an application of the Scholl reaction. The key to the new approach is to use the dimeric compounds of 10-methyleneanthrone as the precursors of 1.
Hydrates of Organic Compounds. XIII. The Confirmation of the Formation of Clathrate-Like Hydrates of Tetrabutylammonium and of Tetraisopentylammonium Polyacrylates
Authors: Nakayama Haruo
Published: July 2006

A thermal analytic method using a differential scanning calorimeter has been applied to aqueous solutions of a series of tetraalkylammonium polyacrylates ((R4NOOCCHCH2)n; R=CH3, C2H5, n-C3H7, n-C4H9, n-C5H11, and i-C5H11). It was found that only tetrabutylammonium polyacrylate and tetraisopentylammonium polyacrylate could form stable hydrates having a large number of moles of water per single R4NOOCCHCH2 unit of the polyacrylates (hydration numbers). The melting points and hydration numbers of these two hydrates were 11.2 °C, 30±1 for the tetrabutylammonium polyacrylate hydrate and 19.5 °C, 42±2 for the tetraisopentylammonium polyacrylate hydrate, respectively. Judging from the melting points, hydration numbers, and the concentration dependence of the dissolution temperatures, these hydrates were regarded as clathrate-like. The tetrabutylammonium polyacrylate hydrate seems to be iso-structural with (n-C4H9)4NF hydrate and the tetraisopentylammonium polyacrylate hydrate with (i-C5H11)4NF hydrate.
Adsorption of Dodecyltrimethylammonium Chloride from the Micellar Solution at Water/Air Interface
Authors: Aratono Makoto , Okamoto Toru , Motomura Kinsi
Published: July 2006

The surface tension of the aqueous solution of dodecyltrimethylammonium chloride (DTAC) was measured as a function of temperature under atmospheric pressure at concentrations below and above the critical micelle concentration. The thermodynamic quantity changes associated with the adsorption of DTAC from its monomeric and micellar states were evaluated and proved to satisfy the thermodynamic relation derived on the assumption that the micelle formation can be treated as the appearance of a macroscopic bulk phase in the solution. Further their values were compared with those of the aqueous solution of dodecylammonium chloride and the influence of the chemical structure of the head group on the adsorption and micelle formation were discussed from the thermodynamic viewpoint.
Preparation and Properties of Ammonium Hexachlorozirconate(IV) and Its Reaction with Gaseous Ammonia
Authors: Ohashi Masao , Yamanaka Shoji , Morimoto Yuhki , Hattori Makoto
Published: July 2006

Ammonium hexachlorozirconate (NH4)2ZrCl6 was prepared by the direct reaction of ZrCl4 with NH4Cl. The X-ray powder diffraction and the density measurements showed that it has a face-centered cubic lattice with a=10.127(2) Å and is isostructural with K2PtCl6. The hexachlorozirconate undergoes ammonolysis in gaseous ammonia at room temperature, forming ZrCl3(NH2)·xNH3 and NH4Cl. The ammonolysis product reverts to the initial (NH4)2ZrCl6 on heating to 250 °C in the ammonia atmosphere. The hexachlorozirconate vaporizes at about 450 °C. The reaction of ZrCl4 with gaseous ammonia was also studied in comparison with that of the hexachlorozirconate.
Synthesis of (E,E)- and (Z,Z)-1,5-Cycloalkadienes by Means of the Electrochemical Cyclization of Allylic 1,ω-Dibromides
Authors: Tokuda Masao , Satoh Kuniaki , Suginome Hiroshi
Published: July 2006

Electrolysis of (E,E)-1,n-dibromo-2,(n-2)-alkadienes (n=12, 14) in tetrahydrofuran gave the corresponding twelve or fourteen-membered (E,E)-1,5-cycloalkadienes, albeit in low yields, together with (E)-4-vinylcycloalkenes and isomeric alkadienes. Similar electrolysis of (Z,Z)-1,n-dibromo-2,(n-2)-alkadienes (n=10, 12, 14) gave the corresponding ten, twelve, or fourteen-membered (Z,Z)-1,5-cycloalkadienes in 11 to 13% yields, with the accompanying formation of (Z)-4-vinylcycloalkenes and isomeric alkadienes.
Effect of Lattice Anions on the Ligand Substitution Reaction of Tris(1,10-phenanthroline)metal(II) Complexes: [M(phen)3]SO4 and [M(phen)3]X2 (M: Fe(II), Co(II), Ni(II); X: Cl−, Br−, I−)
Authors: Yamasaki Shoji , Fujiwara Terufumi , Yamamoto Yuroku
Published: July 2006

The kinetics of the ligand substitution reaction of the title complexes in the solid state have been studied using thermogravimetry (TG) and differential scanning calorimeter (DSC) techniques. For these complex salts, an exothermic peak appears in the DSC curve which correlates with a ligand substitution in which anionatobis(1,10-phenanthroline)metal(II) complexes are formed. The heats of the exothermic reaction for ligand substitution of the sulfates decrease in the order Co(II)>Ni(II)>Fe(II). Isothermal and nonisothermal kinetic analyses were carried out using the exothermic peak. Activation energies of the ligand substitution for the same counterion generally increase with the metal in the order Co(II)<Ni(II)<Fe(II) and for the same metal, Ni(II) or Fe(II), increase with the counterion in the order Cl−<Br−<I−<SO42−. However, for the cobalt complex, the activation energies are almost identical for this series of counterions. From the trends in activation parameters for the ligand substitution, we propose a dissociative mechanism for the sulfates of all complexes studied and for the cobalt complex halides studied. For the halides of the iron(II) and nickel(II) complexes studied, a mechanism involving nucleophilic attack of the halide ions is important.
Synthesis of Dibromoacetyl Derivatives by Use of Benzyltrimethylammonium Tribromide
Authors: Kajigaeshi Shoji , Kakinami Takaaki , Tokiyama Hajime , Hirakawa Takahiro , Okamoto Tsuyoshi
Published: July 2006

The reaction of acetyl derivatives with double the molar quantity of benzyltrimethylammoniun tribromide in dichloromethane–methanol solution at room temperature gave dibromoacetyl derivatives in fairly good yields.
Electrical Double Layer Formed on the Monolayer of Crown Ether Compounds
Authors: Matsumura Hideo , Watanabe Tsutomu , Furusawa Kunio , Inokuma Seiichi , Kuwamura Tsunehiko
Published: July 2006

The binding behavior of metal ions to the monolayers of a crown ether compound has been studied by the surface potential measurements. The obtained data are analyzed from the viewpoint of interfacial electrochemistry, i.e., the electrical double layer theory at the interfaces. The analysis reveals that the generated double layer at a membrane–solution interface after the complexing of metal ions with crown ethers is well described by the Stern model for the electrical double layer; it shows that there exists a possibility to evaluate the binding constants of metal ions with crown ethers under interfacial circumstances.
Use of Propagators in the Hückel Model. VIII. Intermolecular Interaction
Authors: Kano Toshiharu , Nishikawa Kiyoshi , Aono Shigeyuki
Published: July 2006

Intermolecular interactions are analyzed by the propagator method, under the tight-binding approximation. The stabilization energy or the change of charge density due to the intermolecular interaction are expressed in terms of propagators, so that the mechanism resulting above effects is satisfactorily realized. As an interesting example, the intermolecular interaction between guanine and benzo[a]pyrene (a famous chemical carcinogen) is investigated.
Mechanistic Approach to the Sensitization Process of Aromatic Ketones in the Isomerization between Norbornadiene and Quadricyclane
Authors: Arai Tatsuo , Oguchi Takahisa , Wakabayashi Toshio , Tsuchiya Masahiro , Nishimura Yoshinobu , Oishi Shigero , Sakuragi Hirochika , Tokumaru Katsumi
Published: July 2006

The quantum yields for norbornadiene(N)→quadricyclane(Q) and Q→N isomerization were determined in acetonitrile using several substituted benzophenones (BPs) as triplet sensitizers. For the N→Q isomerization, BPs with electron-donating substituents exhibited higher quantum efficiency (0.4–0.6) than BPs with electronaccepting substituents. The quantum yields for Q→N isomerization increased with electron-accepting ability of the substituents on BPs, but were lower than 0.1. The rate constants for quenching of triplet BPs by N and Q were also determined in acetonitrile by means of laser flash photolysis. The rate constants for N were not dependent on the triplet energies (ET) of BPs but dependent on electronic properties of the substituents on BPs. On the contrary, those for Q increased with decreasing ET of BPs and with increasing Hammett’s σ constants of the substituents of BPs. Based on these observations an addition-elimination process is proposed for the N→Q isomerization, and an electron transfer process for the Q→N isomerization.
Radical Switch Reaction. A Novel Reaction between Two Free Radicals in a Solvent Cage
Authors: Kobayashi Michio , Gotoh Michiko , Yoshida Masato
Published: July 2006

Studies on the thermal decomposition of t-butyl phenylazo sulfone suggested the occurrence of a radical switch reaction, a novel type of reaction between two radicals. A primary geminate radical pair, t-butanesulfonyl and phenyl radical pair, exchange sulfur dioxide to form a new radical pair consisting of t-butyl and benzenesulfonyl radicals. The generation of benzenesulfonyl radical was confirmed by its ESR spectrum and the isolation of products containing a benzenesulfonyl group.
Protein Engineering of Dihydrofolate Reductase. Improved Catalytic Step of Mutant-Enzymes
Authors: Taira Kazunari , Chen Jin-Tann , Mayer Ruth J , Benkovic Stephen J
Published: July 2006

Two site-specific mutations on dihydrofolate reductase from Escherichia coli have been carried out at the Phe-31 site. From the crystallographic structure the Phe-31 is located at the dihydrofolate binding site and interacts with both the pteridine ring and the p-aminobenzoyl moiety of the substrate. Two mutant enzymes (Phe-31→Tyr and Val) have been purified to homogeneity and characterized by steady-state kinetics. The two mutations are aimed at assessing the hydrophobic interaction between the phenyl ring and the aromatic ring moiety of the substrate. Despite the fact that the first mutation has introduced a polar Tyr-group into a hydrophobic binding site, the Michaelis constant KDHF (KM with saturating NADPH and varying dihydrofolate) has increased only five-fold. The second mutation (Phe-31 →Val-31) results in a 25-fold increase in KDHF. More importantly, the maximum velocity of both mutant enzymes has increased more than 100%, indicating that these are better enzymes under the condition of [substrate]>KDHF. Thus, in both mutant enzymes the decrease in binding has not been translated into a loss of catalytic efficiency.
The Superconductive Compound of the Ba–Y–Cu Oxide
Authors: Ono Akira , Tsutsumi Masayuki
Published: July 2006

Chemical composition of a novel compound in the Ba–Y–Cu–O system is determined. Formulae of the phase is Ba4Y2Cu7O14. X-Ray powder pattern can be indexed successfully on the basis of an orthorhombic unit cell. Stability of the phase is preliminary studied by a thermogravimetric method.
An Improved Synthesis of 8-Amino-8-demethylriboflavin
Authors: Kasai Sabu , Fritz Bernhard J , Matsui Kunio
Published: July 2006

8-Amino-8-demethylriboflavin was synthesized from 3-nitro-4-methylaniline N-d-riboside by selective reduction of the N-glycoside with sodium borohydride, followed by hydrogenation of the nitro group in the presence of Raney’s catalyst. The obtained phenylenediamine was condensed with violuric acid to give the flavin in a high yield.
Effect of Polymer Matrices on Oxygen-Binding of a Cobalt Porphyrin Complex
Authors: Ohyanagi Manshi , Nishide Hiroyuki , Suenaga Koichi , Nakamura Takehiko , Tsuchida Eishun
Published: July 2006

Oxygen-binding of the (1-methylimidazole)-[α,α′,α″, α'″-5,l0,15,20-tetrakis(o-pivalamidophenyl)porphinato]cobalt(II) complex fixed in polymer membranes, poly-(dimethylsiloxane), poly(butyl methacrylate), and poly(methylmethacrylate), was studied spectroscopically. The apparent oxygen-binding affinity increased with oxygen solubility in the polymer matrix, which was corrected with the solubility coefficient of oxygen in the polymer.
Multi-Ionic Potential and Membrane Permeability Matrix. II. Na+–Ca2+ Bi-Ionic System with a Cation-Exchange Membrane and Effects of Cl− on Cation Transport
Authors: Kaibara Kozue , Inoue Hiroyoshi , Kimizuka Hideo
Published: July 2006

Transport characteristics of Na+–Ca2+ bi-ionic system with a highly selective cation-exchange membrane were investigated on the basis of nonequilibrium thermodynamic theory. As a principal transport parameter, the membrane permeability matrix or membrane conductance matrix can be estimated from the membrane potential, conductance, and ion flux data. Significances of diffusional and electroconductive processes of ion transport across membrane were systematically discussed in terms of these matrix elements. Partial contributions of inter-cationic (Na+–Na+, Na+–Ca2+, and Ca2+–Ca2+) correlations to the membrane transport process of ions were examined by means of comparing the estimated values of corresponding matrix elements. It was suggested that Ca2+ ions, of which membrane concentrations are kept at high level independently of the Na+/Ca2+ concentration ratio of external aqueous solutions, play a critical role in the membrane transport phenomena. Participations of Cl− transport in the cation-exchange processes were also discussed on the basis of membrane conductance matrix theory.
Optical and ESR Spectra for High-Spin Tetrahedral Complexes of Co(III) and Co(II) in Keggin-Structure Heteropolytungstate
Authors: Kojima Kazuo , Matsuda Jiro , Kojima Norimichi , Ban Toshiro , Tsujikawa Ikuji
Published: July 2006

The ligand-field spectra for the cobalt complexes in the single crystals of K3H2[CoIIIW12O40]·16H2O and K4H2[(COII, ZnII)W12O40]·nH2O have been observed at several temperatures above 1.4 K and assigned under D2 site symmetry. In the spectrum of the elongated CoIIIO4 complex, two absorption bands of 8250 and 8953 cm−1 strengthen with increasing temperature by vibronic mechanism. The X-band ESR spectra of both complexes have also been measured at 77 K. The signal from the Co(III) complex is not observed. The signal of the high-spin Co(II) complex of tetrahedral symmetry is unequivocally observed even at relatively high temperature of 77 K. From the analysis of the ESR spectrum, it is concluded that the CoIIO4 tetrahedron of D2 symmetry is flattened and deviated slightly from axial symmetry.
Optical Resolution by Preferential Crystallization of Dl-Thiazolidine-4-carboxylic Acid
Authors: Shiraiwa Tadashi , Sado Yujin , Komure Masamitsu , Kurokawa Hidemoto
Published: July 2006

Infrared spectrum, solubility, and ternary solubility diagram indicated that Dl-thiazolidine-4-carboxylic acid (Dl-THC) is a conglomerate at room temperature. The free energy of critical nucleation in supersaturated solutions for the crystallization of d- and l-THC was examined to resolve Dl-THC efficiently by preferential crystallization. Successive preferential crystallization of Dl-THC was experimented at 20 °C for an aqueous racemic solution with a supersaturation of 150%, and d- and l-THC with optical purity of 96–100% were obtained in the range of resolution of 58–76%. The optical resolution was more successfully done in 1 mol dm−3 aqueous glycine to give d- and l-THC with optical purity of 93–99% in the degree of resolution of 77–87%. Recrystallization of d- and l-THC obtained with a succeeding treatment with hydroxylamine hydrochloride gave d- and l-cysteine with 100% optical purity.
Synthesis of Arylthio-Substituted 3,8-Diphenyl-1,2-diazacycloocta-2,4,6,8-tetraenes and Their Thermolysis
Authors: Yogi Seiichi , Hokama Kozo , Tsuge Otohiko
Published: July 2006

Nucleophilic substitution of 4,7-dichloro-3,8-diphenyl-1,2-diazocine with arenethiols gave stable 4-arylthio-7-chloro- and/or 4,7-bis(arylthio)-1,2-diazocines. Unsymmetrical 4,7-bis(arylthio)- and 4-acetoxy-7-phenylthio-1,2-diazocines were also prepared from 4-chloro-7-phenylthio-1,2-diazocine. Thermolysis of all the diazocines afforded only arylthio-substituted pyridines with extrusion of benzonitrile.
Photocatalytic Oxidative Dehydrogenation of 2-Propanol with Niobium Oxide Supported on Porous Vycor Glass
Authors: Wada Yuji , Morikawa Akira
Published: July 2006

2-Propanol was catalytically converted to acetone on niobium oxide supported on porous Vycor glass in the presence of oxygen or nitrogen monoxide under UV irradiation. The light of wavelength shorter than 300 nm was effective for the reaction. The VIS-UV absorption measurements showed that niobium oxide was reduced by 2-propanol under the irradiation and Nb4+ formed by the photoreduction was reoxidized by oxygen. The kinetics of the reoxidation was investigated by means of spectroscopic measurements. The redox mechanism is proposed for the photocatalytic oxidation of 2-propanol.