bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Polarographic Anodic Wave in the Presence of Chloride Ions by a New Numerical Method
Authors: Kikuchi Kenji , Murayama Teisuke
Published: July 2006

A new numerical method is applied to the simultaneous diffusion equations describing the anodic process of mercury in solutions in the presence of chloride ions. The terms corresponding to precipitation and dissolution of mercury(I) chloride are included in the differential equations. It is found that the differential equation for precipitate particles should be rewritten using the backward space difference method for successful computation.
Structures of New [4+2]-Cycloadducts from Diels–Alder Reactions of Methyl 2-Oxo-2H-pyran-5-carboxylate with 2-Methyl- and 2-Methoxy-1,3-butadienes
Authors: Matsui Takanao , Kitajima Shinji , Nakayama Mitsuru
Published: July 2006

A Diels–Alder reaction of methyl 2-oxo-2H-pyran-5-carboxylate (1) with isoprene gave two stereoisomers, methyl 8-methyl-8-vinyl- and 8-isopropenyl-3-oxo-2-oxabicyclo[2.2.2]oct-5-ene-6-carboxylates. On the other hand, only a stereoisomer from a reaction of 1 with 2-methoxy-1,3-butadiene, methyl 8-methoxy-8-vinyl-3-oxo-2-oxabicyclo[2.2.2]oct-5-ene-6-carboxylate was obtained. The stereostructures of these adducts were determined by NMR spectral data and single-crystal X-ray analyses.
Stereochemical Behavior of Intermediary Compounds in the Amine-Catalyzed Knoevenagel Reaction
Authors: Tanikaga Rikuhei , Konya Naoto , Hamamura Kazumasa , Kaji Aritsune
Published: July 2006

Treatment of the active methylene compounds and aldehydes with a catalytic amount of a secondary amine produces thermodynamically stable alkenes, and the intermediary amino compounds are isolated. The reaction involves many reversible steps, and the stereochemistry of products is determined in the elimination step from the intermediary compounds via stable planar carbanions, in which the small difference in the steric requirements of two electron-withdrawing groups is effective. Steric and electronic effects in the intermediates sometimes bring about the carbon–carbon bond fission with recovery of active methylene compounds, and these effects prevent the Knoevenagel reaction from occurring.
Cobalt-Catalyzed Hydrohydroxymethylation of Formaldehyde: Effect of Ru3(CO)12 and Phenol
Authors: Murata Kazuhisa , Matsuda Akio , Masuda Takashi
Published: July 2006

A catalyst system, containing Co2(CO)8, Ru3(CO)12, and phenol, was found to be effective for the hydrohydroxymethylation of formaldehyde to give ethylene glycol with the yield of ca.65%, better than those previously reported.
The Catalytic Reduction of Aldehydes and Ketones with 2-Propanol over Hydrous Zirconium Oxide
Authors: Shibagaki Makoto , Takahashi Kyoko , Matsushita Hajime
Published: July 2006

Reduction of aldehydes with 2-propanol proceeded efficiently by catalysis with hydrous zirconium oxide to give the corresponding alcohols. Most ketones also were reduced efficiently, but conjugated or sterically hindered ketones resisted the reduction. The reduction was carried out with primary, secondary, or tertiary alcohols, and only secondary alcohols served as hydrogen donors. Kinetic experiments have indicated that the reaction rate is of first-order dependence on each of the concentrations of the carbonyl compound, 2-propanol, and the catalyst. An observation of the primary isotope effect has suggested that a step of hydride transfer from absorbed 2-propanol to absorbed carbonyl compound constitutes the rate-determining step for the reduction.
Simple Synthesis of (Z)-12-Nonadecen-9-one, (Z)-13-Icosen-10-one, the Sex Pheromone of Peach Fruit Moth, and (Z)-5-Undecen-2-one, a Biologically Active Molecule from the Pedal Gland of the Bontebok
Authors: Yamashita Masakazu , Matsumiya Kaoru , Murakami Kotomi , Suemitsu Rikisaku
Published: July 2006

A simple and convenient synthesis of (Z)-12-nonadecen-9-one, (Z)-13-icosen-10-one, the sex pheromone of the peach fruit moth, and (Z)-5-undecen-2-one, the pheromone from the pedal gland of the bontebok, is described. These pheromones were readily synthesized using successive alkylation of acetone dimethylhydrazone in one-pot.
An MO Study of Fragmentation Mechanism of Ethane and Propane Radical Cations
Authors: Osamura Yoshihiro , Takeuchi Takae , Nishimoto Kichisuke
Published: July 2006

The decomposition mechanisms were studied for ionized species of ethane and propane in the low-energy region by using an ab initio molecular orbital method. Calculations show that rather complex fragmentation processes may occur in addition to a simple cleavage of C–C and C–H bonds. In order to examine the possibility of an elimination of H2 or CH4 from the radical cation of saturated hydrocarbons, the potential energy curves were calculated for both 1,1- and 1,2-eliminations. An energy barrier of 1,2-elimination was estimated to be small, but a 1,1-elimination can also possibly occur. It was also found that a single C–H bond scission of the parent radical cation may occur with the same order of energy for the H2 loss. The present results are qualitatively in a good agreement with the experiments.
The Preparation of Colloidal Precious Metal Particles Using Copolymers of Vinyl Alcohol–N-Vinylpyrrolidone
Authors: Meguro Kenjiro , Nakamura Yukari , Hayashi Yoshihiro , Torizuka Makoto , Esumi Kunio
Published: July 2006

Precious metal particles of platinum and silver have been prepared by the reduction of metal salts dissolved in an aqueous solution of a copolymer of vinyl alcohol and N-vinylpyrrolidone with methanol. The stable platinum sols were obtained in the presence of poly(vinyl alcohol), poly(N-vinylpyrrolidone), and their copolymers, but their particle sizes hardly changed with the ratio of N-vinylpyrrolidone in the copolymer. On the other hand, colloidal stable silver sols were obtained only in the presence of a copolymer. Further, with an increase in the ratio of N-vinylpyrrolidone in the copolymer, the particle size of silver became small.
Cobalt(III) Complexes Containing an Aldonic Acid
Authors: Tsubomura Taro , Yano Shigenobu , Yoshikawa Sadao
Published: July 2006

Stable complexes of the type [Co(aldonato)(en)2]+, where en is ethylenediamine and aldonato is the diacid anion of d-gluconic acid or l-mannonic acid, were prepared by the reaction of aldonic acid lactones with rac-[Co(CO3)(en)2]+. Two diastereomers (Δ and Λ) have been separated by ion-exchange chromatography from each of the aldonato complexes. These complexes were characterized by NMR, electronic absorption, and circular dichroism spectra. The structures of all four complexes were found to have an aldonato ligand which coordinates bidentately through an oxygen atom of the carboxylato group and an oxygen atom of the deprotonated hydroxyl group on C(2).
Photochemical Fatigue Resistances and Thermal Stabilities of Heterocyclic Fulgides in PMMA Film
Authors: Kaneko Akira , Tomoda Akihiko , Ishizuka Mitsuo , Suzuki Hisao , Matsushima Ryoka
Published: July 2006

Thermal stabilities of the colored forms at 80°C and photochemical fatigue resistances against coloration–discoloration cycles were measured in PMMA thin film, using 14 derivatives of fulgide with different heterocyclic structures. The indolyl (12), oxazolyl (13), and thiazolyl (14) derivatives showed very low thermal degradabilities (TD≤1.5%/day) while 12 and pyrazolyl derivative (9) showed low photochemical fatigues (PF≤0.2%/cycle), as compared with the furyl (1), thienyl (2), and pyrrolyl (3) derivatives. However, many of them featured low photo-responsiveness and low absorptivities for coloration on UV irradiation.
A Consideration of the Charge Density of Polyelectrolytes Based on a Layer Model in Solution
Authors: Kaneko Tetsuo
Published: July 2006

In a model system where layers formed by aggregations of polyelectrolyte molecules are mutually parallel in a solvent, the surface-charge density of the layers is estimated by solving the one-dimensional Poisson–Boltzmann equation. The surface-charge density at a over temperature, T, can be determined depending on the number, ng, of charged groups per unit of the volume in a layer of polyelectrolytes and on the thickness, Δx, of the layer, if the distance between layers of polyelectrolyts is sufficiently large. This surface-charge density is evaluated by assuming that ng is given by the reciprocal of the cubed mean length between neighboring charged groups in a polyelectrolyte molecule and that Δx is of the order of an ion diameter, possibly including the hydration sheath. The surface-charge density given by the layer model agrees well with that semiempirically given by a rod-like polyelectrolyte model. Also, the ratio of the total charge of a layer to the total charge of the charged groups in the layer agrees well with the degree of the ionic dissociation of ionene polymers in a salt-free solution.
General Reactivity of 2-Lithiobenzothiazole to Various Electrophiles and the Use as a Formyl Anion Equivalent in the Synthesis of α-Hydroxy Carbonyl Compounds
Authors: Chikashita Hidenori , Ishibaba Megumi , Ori Keiji , Itoh Kazuyoshi
Published: July 2006

The reaction of 2-lithiobenzothiazole with a variety of electrophiles such as aldehydes, ketones, carboxylic esters, lactones, nitriles, and amides afforded the expected addition and substitution products. Trimethylsilyl chloride readily reacted with the benzothiazolyl anion to give 2-trimethylsilylbenzothiazole, while common alkyl halides including primary iodide and benzyl halides, as well as epoxides, did not react with the anion. This characteristic nucleophilicity of the anion was also demonstrated by its reaction with phenacyl halides and 5-chloro-2-pentanone leading to the formation of benzothiazolyl-substituted small-ring ethers. In order to demonstrate the value of 2-lithiobenzothiazole as a masked formyl anion, 2-(α-hydroxyalkyl)benzothiazoles were transformed into α-hydroxy carbonyl compounds in three reaction steps without masking the α-hydroxy groups. Quaternization of various 2-(α-hydroxyalkyl)benzothiazoles with methyl iodide in DMF afforded the corresponding 2-(α-hydroxyalkyl)-3-methylbenzothiazolium iodides in high yields and the subsequent alkylation or reduction of the C=N+ link was readily accomplished with organolithium and Grignard reagents or sodium borohydride leading to the corresponding 2-(α-hydroxyalkyl)-3-methylbenzothiazolines with or without another 2-substituents. Hydrolysis of former compounds performed in aqueous acetonitrile, buffered to pH 7 and containing AgNO3, gave the desired α-hydroxy ketones.
Solution Structure and Preferred Orientation of 3,7-Dibromo-10H-phenothiazine Dissolved in Nematic Liquid Crystal
Authors: Fujiwara Hideaki , Watanabe Masayuki , Yamanaka Iwao , Takagi Tatsuya , Sasaki Yoshio
Published: July 2006

The NMR spectrum of the title compound has been measured in nematic phase ZLI1167 and analyzed to obtain the direct couplings. The direct couplings were interpreted by assuming a folded structure of the tricyclic framework. The dihedral angle of the two phenyl rings is determined to be 149.1±2.5° and a value of 170±3° is obtained for the angle of S···N–H. The NH proton is concluded to occupy a “equatorial” position on the central ring in a boat form. The preferred orientation of the molecule in ZLI1167 is discussed by comparing the principal axes of order tensor with those of the moment of inertia.
Antimony(V) Arsenatophosphate as a Thermally Stable Cation Exchanger: Selective Adsorption of Alkaline Earth and Transition Metal Ions on Its Column
Authors: Varshney K G , Khan A A , Khan A R
Published: July 2006

A new inorganic ion exchanger based on antimony has been prepared viz. antimony(V) arsenatophosphate, which has shown a peculiarly high thermal stability and selectivity for alkaline earth and transition metal ions. As a result, its column use has been demonstrated for the separation of mercury from magnesium and zinc and of iron from other transition metals. A tentative formula has also been proposed for the material, on the basis of its chemical analysis and other characterization studies.
Organophosphorus Analogues and Derivatives of the Natural l-Amino Carboxylic Acids and Peptides. I. Enzymatic Synthesis of d-, Dl-, and l-Phosphinothricin and Their Cyclic Analogues
Authors: Natchev Ivan A
Published: July 2006

Acetylation of d-, Dl-, and l-3-amino-2-pyrrolidinone (1) to the 3-acetamido derivative 2 and treatment with ethyl methylphosphinate afforded the addition product 3. Strict selectivity was observed in the enzyme-catalyzed hydrolysis with the enzyme phosphodiesterase I, acylase, glutaminase, and α-chymotrypsin. The ester 7 and 1,2-azaphospholidine (8) were isolated by esterification of l-phosphinothricin (6).
The Valence Control and Catalytic Properties of La2−xSrxNiO4
Authors: Nitadori Taihei , Muramatsu Motohiko , Misono Makoto
Published: July 2006

A series of La2−xSrxNiO4 catalysts (x=0–1.0) with a K2NiF4-type structure were prepared, and the average oxidation number of the Ni ion and the stoichiometry of the oxygen in the catalysts were measured. We also investigated the relationships between the reactivity of the catalysts and their catalytic activity for oxidation. The average oxidation number of the Ni ion increased monotonously from 2.32 (x=0) to 2.90 (x=1.0) upon the Sr substitution, and the composition changed with the x value from oxygen-excess (x=0–0.2) to oxygen-deficient (x=0.6–1.0), via a stoichiometric composition at x=0.4. In the range of x=0–0.2 (oxygen excess), the desorption peaks of oxygen in TPD (temperature-programmed desorption) were observed at about 300 °C; these results were ascribable to the excess oxygen. In this range, the oxidizing power of the surface, which was measured by the reduction of the catalysts by CO, was comparatively high. For x=0.4–1.0 (stoichiometric to oxygen-deficient), the oxygen desorbed at a higher temperature, and the amounts increased in accordance with the increase in the oxygen deficiency. The oxidizing power of the surface similarly increased with x values up to x=0.8. The composition of metal on the surface generally reflected that in the bulk, as judged from XPS. The catalytic activity for the oxidation was in parallel with the oxidizing power of the surface in x=0.4–1.0.
Liquid Structure of N,N-Dimethylformamide, Acetonitrile, and Their 1 : 1 Molar Mixture
Authors: Radnai Tamas , Itoh Sumiko , Ohtaki Hitoshi
Published: July 2006

Liquid structures of pure N,N-dimethylformamide (DMF) and acetonitrile (AN) as well as of their 1 : 1 molar mixture were investigated by X-ray diffraction at 25 °C. The careful reinvestigation of pure DMF led to a good reproducibility of the previous result. Slight deviations in the structural parameters are discussed and a detailed parameter table is reported. A simple model in which each AN molecule has 2 neighbors at an average distance of 330 pm describes the more ordered first neighbor structure of pure AN. The main interaction forming the structure is of dipole–dipole type, in agreement with previous findings. In the 1 : 1 molar mixture a dipole–dipole model also leads to a satisfactory description of the first neighbor structure. The preferred orientation is that with dipoles in the antiparallel position. A central DMF molecule has 1.75 neighboring AN molecules in average at a distance of 316 pm. The same stands for DMF around AN. No evidence for other kinds of interaction, e.g., weak H-bond type intermolecular interactions could be found in the mixture.
The Synthesis and Thermal Behavior of Lithium cyclo-Hexaphosphate
Authors: Watanabe Makoto , Murata Khoichi , Maeda Mioko
Published: July 2006

Lithium cyclo-hexaphosphate hexahydrate was made by heating a mixture of 85%-phosphoric acid and dilithium carbonate at an Li/P molar ratio of 1.4 at 200 (1 h), 275 (5 h), and then 420 °C (3 h). The thermal product was handled with a wet chemical method developed in this study. The cyclo-hexaphosphate was stable at room temperature (20–30 °C), while a small part of it decomposed to phosphates with shorter chain lengths above about 60 °C in air. The cyclo-hexaphosphate was transformed thermally to crystalline long-chain polyphosphates upon heating above 530 °C.
Footprint Catalysis. II. Molecular Recognition of Footprint Catalytic Sites
Authors: Morihara Kensaku , Nishihata Emiko , Kojima Mari , Miyake Sayoko
Published: July 2006

In order to investigate the molecular recognition capability of “footprint” catalytic sites, the affinities of nine “footprint” catalysts for eleven competitive inhibitors, closely related to template molecules, were estimated through the competitive inhibition constants, Ki. An examination of the affinity revealed that the recognition by “footprint” catalytic sites was so highly specific that it could recognize not only the whole, but also the partial, structures of the bound molecules.
The pH Titration Study of Lithium Ion Adsorption on λ-MnO2
Authors: Ooi Kenta , Miyai Yoshitaka , Katoh Shunsaku , Maeda Hiroshi , Abe Mitsuo
Published: July 2006

The pH titration curves of λ-MnO2 showed apparently dibasic acid character toward Li+ ions, but a monobasic acid character toward Na+, K+, Rb+, and Cs+ ions. The adsorptive capacities of alkali metal ions increased in the order; K+, Rb+, Cs+<Na+<<Li+ at pH 10. Overall equilibrium constants were calculated by a simplified Gaines-Thomas equation from the titration curves based on the ion-exchange mechanism. Thermodynamic data were derived for the system of (0.1-M LiCl+LiOH)(1 M=1 mol dm−3) at different temperatures. Effects of ionic strength and adsorption temperature on the lithium ion adsorptivity were studied using (LiCl+LiOH) and (KCl+LiOH) solutions.
Decalino-14-crown-4. New Type of Lithium Ion Selective Ionophore
Authors: Kobiro Kazuya , Hiro Toshitaka , Matsuoka Toshihiro , Kakiuchi Kiyomi , Tobe Yoshito , Odaira Yoshinobu
Published: July 2006

A new type of crown ether, decalino-14-crown-4, has been synthesized and found to be a highly selective and effective ionophore for lithium ion.
A Determination Method of Absolute Configuration
Authors: Toda Fumio , Mori Koji , Sat\={o} Atsushi
Published: July 2006

A determination method of absolute configuration of sulfoxides, amines, and aminoalcohols by measuring their 1H NMR spectra in the presence of optically active 2,2′-dihydroxy-1,1′-binaphthyl and 1,6-di(o-chlorophenyl)-1,6-diphenyl-2,4-hexadiyne-1,6-diol, was reported.
Synthesis and Properties of 4H-Benzo[hi]pyrrolo[2,1,5-cd]indolizin-4-ones
Authors: Noguchi Michihiko , Yamamoto Takashi , Kajigaeshi Shoji , Saito Keiji , Arai Tsuyoshi
Published: July 2006

3-Phenyl-4H-benzo[hi]pyrrolo[2,1,5-cd]indolizin-4-one (5) was prepared by saponification accompanied by the decarboxylation of the corresponding 1,2-bis(methoxycarbonyl) derivative, which was obtained by the DDQ oxidation of 5,6-dihydro one. Investigations concerning its spectral data and MO calculations revealed interesting electronic features for 5, e.g., i) a highly polarized structure in the ground state, ii) the exsistence of a peripheral [12]annulene system in acidic media, and iii) a significant stabilization of the excited state by protonation.
Possibility of Superconducting and Other Phases in Organic High Polymers of Polyacene Carbon Skeletons. I. Screened Electron–Electron Interaction—Random Phase Approximation—
Authors: Kimura Minoru , Kawabe Hiroyuki , Nakajima Akihiko , Nishikawa Kiyoshi , Aono Shigeyuki
Published: July 2006

The effective electron–electron interaction in the high polymers of polyacene carbon skeleton is investigated. The appearance of various phases in this system depends on associated parameters characterizing the electron–electron interactions near the Fermi level. The main purpose of this work is to estimate these parameters under the random phase approximation and to presume whether this polymer may or may not be superconductor at room temperature.
Possibility of Superconducting and Other Phases in Organic High Polymers of Polyacene Carbon Skeletons. II. Screened Electron–Electron Interaction —Method of Renormalization Group—
Authors: Kimura Minoru , Kawabe Hiroyuki , Nishikawa Kiyoshi , Aono Shigeyuki
Published: July 2006

The electron–electron interaction which is crucial in determining whether new phases will arise or not in polyacene is investigated by means of the renormalization group. This approach is valuable to effectively include, from the view-point of the group theory, the higher order diagrams not taken into account in the random phase approximation of the previous work. It is found that there is a range of coupling constants where the singlet superconducting phase without simultaneous CDW ordering can be expected.
Potentiometric Studies on Sulfato Complex of Aluminium(III) in Aqueous Solution at Elevated Temperatures
Authors: Matsushima Yoshiyuki , Matsunaga Akio , Sakai Kazuhiro , Okuwaki Akitsugu
Published: July 2006

Equilibria in aluminium sulfate solutions with a 1 mol kg−1 KCl medium and low pH range have been investigated by means of acidity measurements with a hydrogen ion concentration cell from 25 to 125 °C. The results were treated with a nonlinear least squares computer program to analyze the equilibrium constants for aluminium complexes by using a single parameter type of Debye–Hückel equation. The log(K/mol−1 kg) values of the formation constant for the reaction, Al3++SO42−\ightleftarrows[AlSO4]+ varied from 3.35 at 25 °C to 5.34 at 125 °C and were formulated as a function of temperature. The standard enthalpy and entropy of the complex formation computed from the variation of the formation constant with temperature are presented over the experimental temperature range. The species [Al(SO4)2]− was not detected under the present conditions.
81Br NQR and 119Sn Mössbauer Study for MSnBr3 (M=Cs and CH3NH3)
Authors: Yamada Koji , Nose Sayuri , Umehara Takako , Okuda Tsutomu , Ichiba Sumio
Published: July 2006

Successive phase transitions were observed for CsSnBr3 and CH3NH3SnBr3 by means of 81Br NQR and DTA. These compounds are isomorphous with each other and have typical cubic perovskite structures at room temperature. However, with decreasing temperature both compounds showed successive phase transitions and complex 81Br NQR spectra at 77 K. In the case of CH3NH3SnBr3, both 81Br NQR and 119Sn Mössbauer spectra changed markedly with decreasing temperature from those at room temperature. These findings suggested a large distortion of the SnBr6 octahedron from the regular one and were interpreted on the basis of the three-center-four-electron bond model. In relation to these structural changes, a broad-line 1H NMR experiment on CH3NH3SnBr3 was also observed in order to determine the effect of the dynamic properties of the cation.
Study of Polarographic Anodic Wave in the Presence of Sulfate Ions by a Numerical Method
Authors: Kikuchi Kenji , Murayama Teisuke
Published: July 2006

A polarographic anodic wave in the presence of sulfate ions increases with any increase in the concentration of sulfate ions, contrary to the expectation based on a free dissolution of electrode mercury. It does not show any diffusion current plateau. The precipitation of mercury(I) sulfate, the product of an electrode reaction, does not take place within a dropping time. An analysis using a new numerical method previously reported proved that the wave is caused by the formation of a mercury(I) complex, [Hg2(SO4)], with a stability constant of 150 mol−1 dm3.
Reactivities of Stable Rotamers. XXIII. Some Addition Reactions toward the Vinyl Group in 9-(2-Vinyl-1-naphthyl)fluorene Rotamers
Authors: Oki Michinori , Tsukahara Jiro , Sonoda Yoriko , Moriyama Kazuhiro , Nakamura Nobuo
Published: July 2006

Addition reactions to the vinyl group of the ap and the sp rotamers of 9-(2-vinyl-1-naphthyl)fluorene were carried out. Whereas action of sulfuric acid on the sp rotamer caused a cyclization reaction, the ap isomer was recovered under the conditions. While addition of bromine afforded normal products for both the isomers, reaction of chlorine afforded chlorine-substituted products (chloro olefins) in addition to the normal adduct, the formation of the former being predominant, in the sp form. The slightly enhanced reactivity of the sp form relative to the ap in bromination together with the formation of the chloro olefin and the behavior of the sp form in the treatment with sulfuric acid are attributed to the stabilization of the intermediates by the π-participation of the fluorene ring. Other addition reactions, epoxidation, hydrogenation, hydroboration, osmium tetraoxide oxidation, chlorination with (dichloroiodo)benzene, and diimide reduction, which are believed to proceed through a cyclic transition state, have also been studied to show that the rates of the reactions of one isomer are not much different from those of another. Spectroscopic data suggest that the conformation of the vinylnaphthalene portion in both isomers are similar. Little difference in the reaction rates of the two rotamers are attributed to the possible transition state conformation which may not be affected by the steric hindrance of the fluorene ring.
Regioselective Ring Opening Reactions of 1-Aminocyclopropenes via Carbenium Ion and Carbene Intermediates
Authors: Yoshida Hiroshi , Sano Hiroe , Ogata Tsuyoshi , Matsumoto Kiyoshi
Published: July 2006

The reaction of 1-(disubstituted amino)-2,3-diphenylcyclopropenium salt with phenyl- and alkylmagnesium halides afforded, regioselectively, 1-aminocyclopropenes in good yields. The reactions of these 1-aminocyclopropenes were studied under acidic and nonacidic conditions to yield regioselective ring-opening products (C2–C3 and C1–C3 bond fissions of the cyclopropene) associated with the carbenium ions and carbene intermediates, respectively.
Synthesis and Absolute Configuration of the Acetalic Lignan (+)-Phrymarolin I
Authors: Ishibashi Fumito , Taniguchi Eiji
Published: July 2006

The natural (+)-phrymarolin I was stereoselectively synthesized and its absolute configuration was unequivocally determined as being (1S,2S,5R,6S)-1-acetoxy-2-(2-methoxy-4,5-methylenedioxyphenoxy)-6-(2-methoxy-4,5-methylenedioxyphenyl)-3,7-dioxabicyclo[3.3.0]octane.
Asymmetric Hydrocyanation of Aldehydes Using Chiral Titanium Reagents
Authors: Minamikawa Hiroyuki , Hayakawa Satoshi , Yamada Tohru , Iwasawa Nobuharu , Narasaka Koichi
Published: July 2006

Two highly enantioselective methods for hydrocyanation of aldehydes were developed by using chiral alkoxytitanium reagents. Treatment of benzaldehyde with cyanotrimethylsilane in the presence of a chiral alkoxytitanium affords mandelonitrile in good chemical and optical yields. By the use of the chiral cyanotitanium reagent generated in situ from the chiral alkoxytitanium and cyanotrimethylsilane, aliphatic aldehydes are converted into the corresponding cyanohydrins in a highly enantioselective manner.
Rechargeable Lithium Batteries Using Polypyrrole–Poly(styrenesulfonate) Composite as the Cathode-Active Material
Authors: Shimizu Atsushi , Yamataka Kazunori , Kohno Masashi
Published: July 2006

Polypyrrole–polyelectrolyte composite, obtained by electrochemical polymerization on a vapor-grown carbon fiber (VGCF) electrode, was used as a cathode-active material for a rechargeable lithium battery. Poly(styrensulfonate) ion was suitable as a dopant in terms of rechargeability of the battery. The VGCF, which has a fibrous structure, was effective as a current collector for the polymer electrode. The content of the dopant calculated by the molar ratio of sulfur and nitrogen was ca. 30%. The open-circuit voltage was 3.55 V at the time. A charge–discharge, accompanied by an Li+ deinsertion–insertion of the composite, was observed. The chargedischarge mechanism is similar to that of inorganic cathode-active materials that show Li+ intercalation. The battery was cycled stably beyond 30 times between 3.66 and 1.50 V at a constant current of 0.889 mA cm−2. An experimental capacity of 57 Ah kg−1 was obtained at the largest value on the basis of the weight of the active material. There is a possibility of developing a light-weight rechargeable battery using the polypyrrole–poly(styrenesulfonate) composite.
α,β-Unsaturated Nitriles in Heterocyclic Synthesis. Novel Synthesis of Pyridines and Thieno[2,3-b]pyridine Derivatives
Authors: Elgemeie Galal E H , Elfahham Hassan A , Nabey Hesham A
Published: July 2006

Arylmethylenecyanothioacetamide reacts with ethyl acetoacetate and acetylacetone to give the corresponding 3-cyano-2(1H)-pyridinethione derivatives, which can be alkylated at sulfur atom and cyclized into the corresponding thieno[2,3-b]pyridine derivatives.
Manganese “Picnic Basket” Porphyrins: Cytochrome P-450 Active Site Analogues
Authors: Collman James P , Brauman John I , Fitzgerald Jeffrey P , Hampton Philip D , Naruta Yoshinori , Michida Takashi
Published: July 2006

This paper describes studies of a new class of cytochrome P-450 model compounds called the “picnic basket porphyrins.” The picnic basket porphyrins are unsymmetrical porphyrins with one face sterically protected by a superstructure and the other unhindered. The manganese(III) porphyrins have been investigated as shape selective catalysts using oxygen atom donors in the presence of a sterically bulky imidazole. This paper presents ligand binding studies and competitive olefin epoxidations which lead to the surprising conclusion that catalysis by the manganese picnic basket porphyrins occurs exclusively on the sterically unhindered face indicating reaction by the minor catalyst component and not the selective major catalyst component.
Metal-Catalyzed Organic Photoreactions. Iron(III)-Catalyzed Photoreactions of Aldo- and Ketohexoses
Authors: Ichikawa Shuji , Tomita Isao , Hosaka Akira , Sato Tadashi
Published: July 2006

Under UV irradiation in the presence of iron(III) chloride or iron(III) triflate in pyridine, d-glucose, d-mannose, and d-galactose underwent a selective bond cleavage at the C1–C2 position, producing 4-O-formyl-d-arabinopyranose and 4-O-formyl-d-lyxopyranose. d-Fructose, under the same conditions, gave arabino-γ-lactone. The reaction was interpreted in terms of the photoinduced electron transfer within a chelate of iron ion with the carbohydrate molecule.
Optical Isomer Effect on the Mechanochemical Interaction of Mandelic Acid with Talc Powder
Authors: Ikekawa Akiko , Hayakawa Sohachiro
Published: July 2006

Mandelic acid was ball-milled with talc powder, and the optical isomer effect on the IR spectral change was investigated. The change showed that a complex was formed between talc and the hydroxyl group and the COOH group of mandelic acid. It was also shown that the covalent character in the bond of the C=O group with talc was greater for (RS)-mandelic acid than for the R-isomer and the S-isomer. The change in the region of the carbonyl-stretching vibration was affected by the humidity in the ball-milling atmosphere, and the effect on the R-isomer was greater than the effect on the S-isomer. Magnesium mandelate powder was obtained from an ethanolic suspension of the ball-milled mixture with talc. The IR spectra and the elemental analysis showed that the C=O group was covalently bonded to Mg in the complex of the (RS)-compound and that it was ionically bonded in the complex of the R-isomer and the S-isomer. The thermal analysis showed that the decomposition temperature for the complex of the R-isomer was different from the temperature for the complex of the S-isomer. It was suggested that talc powder had a chiral surface when it was mechanically treated.
Activated Nitriles in Heterocyclic Synthesis. Synthesis of Pyrimidine Derivatives
Authors: Sadek Kamal Usef , El-Maghraby Mohamed Abdallah , Selim Maghraby Ali , Elnagdi Mohamed Hilmy
Published: July 2006

Synthesis of polyfunctional pyrimidine derivatives via the reaction of acrylonitrile derivatives 1a and b with α,β-unsaturated nitriles 2a–f has been reported.
Kinetics of Oxidation of Aliphatic Ketones with Bromamine-T in Acid Medium
Authors: Mahadevappa Dandinasivara Siddalingaiah , Swamy Putta
Published: July 2006

The kinetics of oxidation of 2-propanone, 2-butanone, 2-pentanone, 3-pentanone, and 4-methyl-2-pentanone by sodium salt of N-bromo-p-toluenesulfonamide or bromamine-T (BAT) in presence of HClO4 was studied at 30 °C. The rate law is:

−\fracd[BAT]dt=k[BAT]0[ketone]1[H+]1.

Variation of ionic strength of medium or addition of reaction product p-toluenesulfonamide have no effect on the rate. The dielectric effect is positive. The acid-catalyzed enolization of ketone is assumed to be the rate-limiting step and enolization rate coefficients have been calculated. Proton inventory studies made in H2O–D2O mixtures have been employed to calculate the isotopic fractionation factors. Isokinetic temperature is 320 K indicating enthalpy as a controlling factor.
Strong Solvent and pH Dependence in the Photolysis of Diphenylmethanimine
Authors: Giumanini Angelo G , Verardo Giancarlo , Poiana Marco
Published: July 2006

Benzophenone imine photolysis shows a strong product solvent and pH dependence: Diphenylmethane is by far the dominating outcome in methanol.
Counter Ion Effect on the 13C NMR Paramagnetic Relaxation Rate of Water–Methanol or Water–Dimethyl Sulfoxide Mixed Solvent with Ni(II) Solute
Authors: Kobayashi Kanya , Yokoi Masatoki , Kubota Eiji
Published: July 2006

The paramagnetic-salt induced 13C spinlattice relaxation rate of solvents methanol and dimethyl sulfoxide was measured for Ni(ClO4)2, NiSO4, and NiBDS (BDS: m-benzenedisulfonate) solutions in 50 wt.% mixture of each of the solvents and water. Relatively small relaxation rates were found for the solutions containing NiSO4. This fact is ascribed to the exclusion of some solvent molecules from the first coordination shell of Ni2+ due to the coordination of SO42− to Ni2+.
A BEDT-TTF Complex Including a Magnetic Anion, (BEDT-TTF)3(MnCl4)2
Authors: Mori Takehiko , Inokuchi Hiroo
Published: July 2006

The title charge-transfer complex is prepared and its crystal structure is determined (BEDT-TTF: bis(ethylenedithio)tetrathiafulvalene). One third of the BEDT-TTF molecules is incorporated in the anion sheet, and holds about 2+ charge. The remaining donors form a conducting sheet with a similar arrangement to β′-(BEDT-TTF)2ICl2.
Synthesis and Structure of cis(O,O),trans(N,N)-Chlorobis(8-quinolinolato-N1, O8)nitrosylruthenium
Authors: Kamata Yukiko , Miki Eiichi , Hirota Reiko , Mizumachi Kunihiko , Ishimori Tatsujiro
Published: July 2006

Molecular structure of the title compound has been determined by the X-ray diffraction. The Cl atom is in cis to the NO group, the O atom of one of the two quinolinolato ligands is in trans to the NO group, and the coordinating N and O atoms of two quinolinolato ligands are in cis(O,O) and trans(N,N) configuration.
Catalytic Asymmetric Cyclization of Some Bromohydrins with Chiral Cobalt Complex
Authors: Takeichi Tsutomu , Takakura Teruo , Ishimori Michihiro , Tsuruta Teiji
Published: July 2006

Asymmetric cyclization of a variety of bromohydrins with base was examined in the presence of an optically active cobalt(salen) type complex. Optically active oxiranes of modest optical purities were obtanied. erythro-3-Bromo-2-butanol and threo-3-bromo-2-butanol were cyclized similarly, and only trans-2,3-dimethyloxirane and cis-2,3-dimethyloxirane were obtained, respectively, indicating that the cyclization of bromohydrin proceeds by complete SN2 type reaction.
Formation of N,N′-Disubstituted Methanediamine Derivatives from Hexamethyldisilazane and Aldehydes via Stepwise Reactions
Authors: Nishiyama Kozaburo , Saito Masaki , Oba Makoto
Published: July 2006

The ZnCl2-catalyzed reaction of aldehydes with hexamethyldisilazane (HMDS) resulted in the formation of N,N′-disubstituted methanediamines, which were found to be formed stepwisely via 1 : 1- and 1 : 2-adducts of HMDS and aldehydes.
Mass Spectrometry of Molecular Adsorbates Using Laser Desorption/Laser Multiphoton Ionization
Authors: Zare Richard N , Hahn Jong Hoon , Zenobi Renato
Published: July 2006

Current and potential applications of a new mass spectrometric technique for the analysis of nonvolatile and thermally labile substances are reviewed. The method is compared to other approaches and its advantages are discussed.
Diene-Containing Lipids as Probes for Phase-Transition Behavior of Lipids in Liposomes
Authors: Takeoka Shinji , Iwai Hidetaka , Ohno Hiroyuki , Tsuchida Eishun
Published: July 2006

The absorption maximum (λmax) of 1,2-bis(2,4-octadecadienoyl)-sn-glycero-3-phosphorylcholine (DODPC), dispersed in an aqueous medium as liposomes, showed blue shift from 256.8 nm to 241.8 nm when these liposomes were cooled down from liquid crystalline state to gel state. The blue shift is explained to be due to stronger interaction between diene groups at gel state. This diene-containing lipid is examined to be an excellent membrane probe because it is typical phospholipid and miscible with several lipids. Furthermore, the dienoyl groups are known to be settled in the definite positions in bilayer membrane by suitable chemical modification. Phase transition behaviors of various 2,4-octadecadienoyl-containing phosphorylcholines as analogs for DODPC have also been investigated. Although they had similar spectral shifts at gel-to-liquid crystalline phase-transition temperature, their phase-transition temperatures and magnitude of λmax shifts were revealed to be related directly and therefore be governed by the different packing of the diene groups in bilayer membrane. DODPC was mixed with 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine, or cholesterol, and phase behaviors of these mixed liposomes were also examined. Phase-transition of the mixed liposomes was detected easily by the shift of its λmax with high sensitivity. Results were quite comparable to those obtained from other measurements, such as DSC, NMR, and so on.
Activation of Aromatic Carbon–Hydrogen Bonds by Palladium(II) Acetate–Dialkyl Sulfide Systems. Formation and Characterization of Novel Diphenyltripalladium(II) Complexes
Authors: Fuchita Yoshio , Hiraki Katsuma , Kamogawa Yasuko , Suenaga Miho , Tohgoh Kazutaka , Fujiwara Yuzo
Published: July 2006

Palladium(II) acetate reacts with benzene in the presence of dialkyl sulfides at 70 °C to afford novel diphenyltripalladium(II) complexes of [(R1SR2)PhPd(μ-MeCO2)2Pd(μ-MeCO2)2PdPh(R1SR2)] (1a; R1=But, R2=CH2But: 1b; R1=R2=Bui: 1c; R1=R2=Pri: 1d; R1=R2=Et). Adducts, [Pd(MeCO2)2(ButSCH2But)2] and [Pd(MeCO2)2(SPri2)2], prepared by the reactions of palladium(II) acetate and the corresponding dialkyl sulfides in benzene at 5–10 °C, change to 1a and 1c, respectively, on heating in benzene at 70 °C. In contrast, reactions of palladium(II) acetate with toluene or thiophene in the presence of diisopropyl sulfide afford no isolable tolyl-or thienyl-palladium species, but coupling products, i.e. bitolyls or bithienyls, are detected by GLC analysis. Treatment of 1b with styrene produces trans-stilbene, whereas 1c reacts with carbon monoxide as well as carbon dioxide to yield benzoic acid. When palladium(II) acetate and t-butyl phenethyl sulfide are heated at 80 °C in benzene, an adduct [Pd(MeCO2)2(ButSCH2CH2Ph)2] is formed, in sharp contrast with the case of benzyl t-butyl sulfide, which gives a cyclopalladated complex under the same reaction conditions.
Asymmetric Transformation of (RS)-Cysteine via Formation of (RS)-4-Thiazolidinecarboxylic Acids
Authors: Shiraiwa Tadashi , Kataoka Kazuo , Sakata Shinji , Kurokawa Hidemoto
Published: July 2006

Either (R)- or (S)-cysteine ((R)- or (S)-Cys) was efficiently obtained from (RS)-Cys by the asymmetric transformation via formation of (RS)-4-thiazolidinecarboxylic acid ((RS)-THC) or (RS)-2,2-dimethyl-4-thiazolidinecarboxylic acid ((RS)-DMT) and by using (2R,3R)- or (2S,3S)-tartaric acid ((R)- or (S)-TA), as a resolving agent, in acetic acid. The asymmetric transformation was carried out by combination of crystallization of less soluble salt of (S)-THC or -DMT with (R)-TA (or salt of (R)-THC or -DMT with (S)-TA) and epimerization of soluble diastereomeric salt. The (R)- and (S)-THCs from the less soluble salts gave approximately optically pure (R)- and (S)-Cys’s, respectively, in 64% yield. The asymmetric transformation via formation of (RS)-DMT was more successfully achieved by adding 0.1 molar equivalent of salicylaldehyde; that is, hydrolysis of the obtained less soluble salt gave optically pure (R)- and (S)-Cys’s, respectively, in 80% yield based on the (RS)-Cys used as the starting material.
Electrochemical Studies of Poly(mercaptohydroquinone) and Poly(mercapto-p-benzoquinone) Films Prepared by Electropolymerization. III. Basic Behavior and Properties in Aqueous Solutions
Authors: Arai Gorou , Shimamura Shigehiko , Ohtomo Yasunobu , Yasumori Iwao
Published: July 2006

Electrochemical behavior and properties of poly(mercaptohydroquinone)/poly(mercapto-p-benzoquinone)(SQ) films prepared on glassy carbon electrodes (GCE) by anodic polymerization of mercaptohydroquinone were examined in detail by cyclic voltammetry. Almost all hydroquinone and/or p-benzoquinone moieties in SQ films of less than ca. 100 monolayers are electroactive in acidic and neutral buffer solutions. The formal redox potential (as estimated from anodic and cathodic peak potentials) vs. solution pH plot, the slope of which is −60 mV/pH, suggests that the overall electrode reaction of SQ films is an H+/e (1:1) reaction. As to the voltammetric behavior of SQ films, the peak current decreased and the peak potential separaxtion (ΔEp) increased appreciably in unbuffered solutions as compared with those in buffered solutions. The difference of these voltammetric behaviors in unbuffered and buffered solutions increased with increasing pH. Moreover, the peak current increased and ΔEp decreased with rising solution temperature. These noticeable behaviors observed on SQ films are discussed in connection with the charge-transport mechanism within SQ films. SQ films on GCE showed good durability over a wide potential range from the hydrogen evolution potential to +1.0 V vs. SCE.
Host–Guest Complexation of Mono[6-(1-pyridinio)-6-deoxy]-α-cyclodextrin with Several Inorganic Anions
Authors: Matsui Yoshihisa , Fujie Masahiko , Hanaoka Kaori
Published: July 2006

Mono[6-(1-pyridinio)-6-deoxy]-α-cyclodextrin (1) formed 1:1 charge-transfer complexes with such inorganic anions as I−, SCN−, and Br− in an aqueous solution to afford characteristic UV absorption bands. The binding constant (Ka) for a I− complex with 1 was ca. 45 times as large as that with a nonmacrocyclic analog of 1, ca. 10 times that with native α-cyclodextrin, and 4.4 times that with a β-cyclodextrin analog. The I− ion was bound to a dipyridinio analog of 1 more strongly than to 1 by a factor of 10. The Ka values decreased with an increase in the ionic strength of the medium. The complexation was competitively inhibited by ClO4−. Hydrophobic, van der Waals, electrostatic, and charge-transfer interactions were supposed to take part in the complexation co-operatively.
Optical Resolution of 2′-Methoxy-1,1′-binaphthyl-2-carboxylic Acid, and Application to Chiral Derivatizing Agent for HPLC Separation of Enantiomeric Alcohols and Amines
Authors: Miyano Sotaro , Okada Shin-ichi , Hotta Hiroki , Takeda Masayuki , Kabuto Chizuko , Hashimoto Harukichi
Published: July 2006

Racemic 2′-methoxy-1,1′-binaphthyl-2-carboxylic acid was separated on a multi-gram scale into its antipodes via silica-gel column chromatography followed by alkaline hydrolysis of the diastereomeric esters prepared from (R)-1-phenylethanol or (−)-menthol. The molecular structure of (−)-menthyl (aS)-2′-methoxy-1,1′-binaphthyl-2-carboxylate was determined by single-crystal X-ray analysis. The (aS)-acid was converted to crystalline acid chloride, which was conveniently utilized as efficient chiral derivatizing agent for differentiation of enantiomeric alcohols and amines by high-performance liquid chromatography on silica gel. The elution behavior of a pair of diastereomeric esters or amides was explained by the steric interactions between the solutes and the silica-gel stationary phase on the basis of the X-ray analysis.
Kinetic Study for Reactions of Nitrate Radical (NO3·) with Alcohols in Solutions
Authors: Ito Osamu , Akiho Seiji , Iino Masashi
Published: July 2006

The rate constants for the reaction of nitrate radical (NO3·) with alcohols have been determined by flash photolysis method in aqueous and nonaqueous solutions. The reactivity of NO3· in acetonitrile was higher than that in aqueous solution, suggesting that hydrogen bonds between solvent and NO3· or alcohols decrease the reaction rate. From the deuterium-isotope effect, the main reaction path was confirmed to be hydrogen atom abstraction from the carbon atom bonded with the OH group. For 2-methyl-2-propanol, the hydrogen atom abstraction from the OH group was presumed. These reaction paths were confirmed, since the reaction rate constants decreased with an increase in the corresponding bond-dissociation energies. From strong dependency of the rate constants upon the ionization energies of alcohols, the polar transition states of the reactions were suggested.
Facile Synthesis of AM-Toxin II
Authors: Ueda Kazuo , Waki Michinori , Teruya Yoshio , Izumiya Nobuo
Published: July 2006

In a search for a more effective synthetic route for AM-toxins (cyclic tetradepsipeptides), the syntheses of [l-Phe3]AM-toxin II as a preliminary peptide and AM-toxin II as a target were attempted. The cyclization of H–l-Ser(Bzl)-l-Ala–l-Hmb–l-Phe–ONSu (Hmb, 2-hydroxy-3-methylbutanoic acid) in pyridine gave a cyclic monomer in high yield (59%). The removal of O-Bzl in the cyclopeptide and a subsequent dehydration of Ser with carbodiimide–CuCl afforded [l-Phe3]AM-toxin II in 24% yield. AM-Toxin II was synthesized in similar yield as in the case of the analog. The characteristic features of synthetic AM-toxin II were identical to those of the natural one.
Quantitative Mapping of Metal-Centered Dipolar Field in Hemin Dicyano Complex by Solution NMR
Authors: Yamamoto Yasuhiko , Nanai Norishige , Inoue Yoshio , Chûijô Riichirô
Published: July 2006

The metal-centered pseudo-contact shift contribution in the hyperfine shift of NMR resonance of paramagnetic hemin dicyano complex ([FeIII(proto)(CN)2]) in solution was quantitatively determined from the combined use of 1H and 13C NMR data. Taking advantage of the axially symmetric magnetic property for [FeIII(proto)(CN)2] in solution, the paramagnetic metal-centered dipolar field was quantitatively mapped. The highly solvent-dependent magnetic anisotropy, (g2⁄⁄–g2⊥), of this complex in CD3OD was estimated to be 7.2 and the obtained value is placed between the values in D2O (4.4) and in CDCl3 (9.7).
Anomalous Peak Intensities in the EXAFS of Polynuclear Molybdenum Compounds
Authors: Miyanaga Takafumi , Fujikawa Takashi , Matsubayashi Nobuyuki , Fukumoto Takao , Yokoi Kunihiko , Watanabe Iwao , Ikeda Shigero
Published: July 2006

EXAFS (Extended X-ray Absorption Fine Structure) experiments on various polynuclear molybdate and tungstate compounds revealed the unusual phenomenon that Mo–O peaks which should appear at around 1.9 Å in Fourier transforms of the EXAFS spectra for Mo6O192− and PMo12O403− are hardly discernible, while the tungstates and other molybdates give the metal–oxygen peaks normally. It is concluded that the Debye–Waller factors for the metal-bridging oxygen bonds in Mo6O192− and PMo12O403− are exceptionally large (≥0.08 Å). The shape of the Raman bands for the Mo6O192− pertaining to the vibration involving the bridging oxygens supports the large σ values estimated. EXAFS measurements were also performed for AsMo12O403−, SiMo12O404−, and PMo12O403−. The compounds with large Debye–Waller factors seem to be unstable against reductants.