bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses and Properties of the Copper(II) Complexes of the Amphoteric Surfactants, N-Alkyl-β-alanine
Authors: Nakamura Akio , Koshinuma Masakatsu , Tajima Kazuo 
Published: July 2006

Abstract
Copper(II) complexes of amphoteric surfactants, N-alkyl-β-alanine (NAA) (the number of carbon atoms in the alkyl chains: n=2, 4, 6, 8, 10, 12), Were synthesized from NAA and copper(II) chloride dihydrate by mixing in aqueous solutions. The properties and structures of these bluish flaky complexes were investigated by elemental analyses, infrared and far-infrared spectroscopy, electronic diffuse reflection spectroscopy, X-ray diffractometry, and thermal analyses. As a result, all of these complexes were found to be composed of one copper(II) ion and two NAA molecules, regardless of the chain length in the alkyl group, (Cu(NAA)2·2H2O), and were also found to have a laminated structure in the crystalline state. A linear relationship was found between the long spacings (d/nm) of the laminated structure and the numbers of carbon atoms (n) in the N-alkyl substituents; d=0.135n+0.62. From these results it was concluded that copper(II) complex molecules have a trans configuration, and are extended and parallel to the normal line of the laminated planes in the crystal. A multiunilayer model for the molecular arrangement of these copper(II) complexes has been proposed, which is quite different from those so far proposed to explain the long spacings observed for metal soap crystals, lyotropic liquid crystal and so on. Also, the role of the alkyl substituents in complex formation has been indicated.
Dynamic NMR as a Nondestructive Method for the Determination of Rates of Dissociation. XVII. Dissociation of the N–B Bond in the Coordinated Form of 2-[2-(Dimethylaminomethyl)phenyl]-4,4-diphenyl-1,3,2-dioxaborolane and Related Compounds
Authors: Toyota Shinji , Oki Michinori 
Published: July 2006

Abstract
The rates of dissociation of the N–B bonds in the title compounds were reexamined by the dynamic NMR technique to get further insight into the mechanism of dissociation. Entropies of activation were fairly large positive to suggest that the dissociation of a bond of ionic characters is the rate-limiting step. The rates of dissociation were generally larger in nonpolar solvents than in polar solvents, suggesting that the stabilization of the ground state by solvation was important in determining the activation energy for dissociation. Diethyl ether, tetrahydrofuran, and acetone gave larger rate constants of dissociation than those expected from their polarity. Participation of solvent molecules in the dissociation is discussed on the basis of these results. Introduction of various substituents indicated that steric effects as well as electronic effects affect the N–B bond energy.
Diastereoselective Reduction of α,α-Difluoro β-Hydroxy Ketones to syn- and anti-2,2-Difluoro-1,3-diols
Authors: Kuroboshi Manabu , Ishihara Takashi 
Published: July 2006

Abstract
While reduction of α,α-difluoro β-hydroxy ketones with diisobutylaluminium hydride gave a mixture of syn- and anti-diols in various ratios, the reduction in the presence of zinc bromide or zinc chloride-N,N,N′,N′-tetramethylethylenediamine was highly selective and gave syn-2,2-difruoro-1,3-diols predominantly, anti-2,2-Difluoro-1,3-diols were obtained by the reduction of α,α-difluoro β-hydroxy ketones with aluminium isopropoxide.
Octacarbonyldicobalt(0)-Catalyzed Ring-Opening Cyanation of Tetrahydrofuran Derivatives with Trimethylsilyl Cyanide
Authors: Okuda Fumio , Watanabe Yoshihisa 
Published: July 2006

Abstract
Tetrahydrofuran, less strained cyclic ether was effectively cyanated by trimethylsilyl cyanide ((CH3)3SiCN) with its ring-opening to give 5-(trimethylsiloxy)pentanenitrile in 82% yield at 120°C for 23 h in the presence of a catalytic amount of Co2(CO)8. Several tetrahydrofuran derivatives having methyl and alkoxyl groups also reacted with trimethylsilyl cyanide to give the corresponding 5-siloxy nitriles in 25–88% yields. On using oxiranes or oxetanes, which are more strained cyclic ethers, however, no reaction proceeded under the same conditions. In the present reaction, (CH3)3SiCN would firstly coordinate to the cobalt metal center as its isocyanide form to give a cobalt-isocyanide complex, which would be a precursor of active catalyst species in the reaction.
The Production of Methacrylic Acid by the Vapor-Phase Aldol Condensation over V–Si–P Ternary Oxide Catalyst
Authors: Ai Mamoru 
Published: July 2006

Abstract
The vapor-phase aldol condensation of propionic acid with formaldehyde was performed over a V–Si–P ternary oxide catalyst of atomic ratio of 1:2:2.2. The one-pass yield of methacrylic acid was 55 mol% on the charged formaldehyde basis at the propionic acid/formaldehyde molar ratio of 2. The maximum yield of methacrylic acid remained unchanged with the variation in temperature and the dilution of reactants, but it increased with the propionic acid/formaldehyde ratio; the yield reached 82 mol% at the propionic acid/formaldehyde ratio of 6. The effects of reaction variables such as temperature, concentrations of propionic acid, formaldehyde, water vapor, methacrylic acid, and oxygen, and propionic acid/formaldehyde ratio were examined.
Association of Halobenzenes with Cyclodextrins in Aqueous Medium
Authors: Takuma Tatsuyoshi , Deguchi Toshio , Sanemasa Isao 
Published: July 2006

Abstract
The complex formation of cyclodextrin (CyD) with fluoro-, chloro-, bromo-, and iodobenzene has been studied in aqueous medium at 25 °C. It was found that van der Waals force is the main factor to stabilize the complex. Formation constsnts for α and β-CyDs increase with the size of halogen atom, while those for γ-CyD are almost independent of the size.
Aluminium-Containing Polymethylsiloxane as a New Solid Acid Catalyst
Authors: Mishima Shozi , Matsuzaki Isao , Nakajima Tsuyosi , Hiki Toshimichi 
Published: July 2006

Abstract
An aluminium-containing polymethylsiloxane (AMS) was prepared in an aqueous system using methyltrichlorosilane, dimethyldichlorosilane, and aluminium hydroxide as the starting materials, and its applicability as a new solid acid catalyst was examined. AMS is an amorphous hydrophobic solid with a high surface area (ca. 250 m2 g−1) and a relatively high thermal stability (max. 573 K in air). The adsorption of basic indicators indicated that acid sites with a medium strength (pKa=1.5) exist on AMS, and protic acid sites were detected on AMS by the IR spectra of adsorbed pyridine. These acid sites differ from the aprotic sites found on alumina. Though those on AMS are able to catalyze the dehydration of pinacol in the vapor phase, they are inactive for the hydrolysis of methyl acetate in an aqueous system.
Synthesis and Inclusion Properties of “Neutral” Water-Soluble Calixarenes
Authors: Shinkai Seiji , Kawabata Hirosuke , Matsuda Tsutomu , Kawaguchi Hirofumi , Manabe Osamu 
Published: July 2006

Abstract
“Neutral” water-soluble calix[n]arenes, 1n (n=6 and 8) were synthesized for the first time. Below the critical micelle concentrations, they formed host–guest-type complexes with naphthalenesulfonate derivatives used as fluorescence probes. The binding sites showed the hydrophobicity comparable with those of cyclodextrins, and the cavities showed the shape selectivity for these guest molecules.
Studies on the Reactivity of Dicyanodihydroborate with Some Lewis Base Hydrochlorides
Authors: Das M K , Bandyopadhyay S N 
Published: July 2006

Abstract
The reactions of sodium dicyanodihydroborate with various Lewis base hydrochlorides produce mainly the metathesis reaction products in contrast to those of sodium cyanotrihydroborate, which produces cyanoborane adducts. This has been established with the help of IR, 1H and 11B NMR data.
Acid-Catalyzed Hydrolysis of Methoxymethyl Phenyl Sulfoxide without Concomitant Racemization
Authors: Okuyama Tadashi , Toyoda Masayoshi , Fueno Takayuki 
Published: July 2006

Abstract
Methoxymethyl phenyl sulfoxide 1 undergoes acid-catalyzed hydrolysis to give S-phenyl benzenethiosulfinate 5, which is formed rapidly from a primary product, benzenesulfenic acid 3. Formation of 5 follows pseudo-first-order kinetics. Rate constants obtained spectrophotometrically in perchloric acid show that the reaction is dependent on the protonated substrate with the Bunnett–Olsen φ=−0.15. Rate constants for the loss of optical activity of the enantiomeric 1 measured in 80 vol% aqueous dioxane are identical with those obtained spectrophotometrically for the formation of 5. Racemization of the substrate does not take place more rapidly than the fragmentation. The reaction is accelerated by chloride and bromide ions. The halide reaction is first order in acid concentration.
Resolution of Enantiomers by Supercritical Fluid Chromatography with Cellulose Tris(phenylcarbamate) Coated on Silica Gel
Authors: Nitta Tomoshige , Yakushijin Yoshiki , Kametani Takefumi , Katayama Takashi 
Published: July 2006

Abstract
The solvent characteristics of super- and subcritical carbon dioxide for the chromatographic resolution of enantiomers (tarns-stilbene oxide) by chiral cellulose tris(phenylcarbamate) were investigated by altering the pressure (10, 15, 20, and 40 MPa), the temperature (0, 25, and 40 °C), and the concentrations of the modifiers. Among methanol, ethanol, and 2-propanol used as modifiers, methanol is the most effective in terms of the resolution of enantiomers, though 2-propanol gives a slightly high value for the separation factor. When the concentration of alcohol increases, the capacity ratio decreases substantially, but the separation factor decreases only a little. At 40 °C, an increase in pressure results in a decrease in the capacity ratio and a slight increase in the separation factor. These pressure effects may be attributed to the enhanced solubilities of both the solute and the modifier with an increase in the mobile-phase density. The temperature is the most effective variable for the separation factor of enantiomers; it increases as the temperature lowers. Therefore, the resolution becomes higher at 0 °C (subcritical conditions) than at 40 °C on the basis of the same analysis time.
Simple and Convenient Method for Synthesis of 3-O-Sulfonyl- γ-cyclodextrin
Authors: Tahara Tsutomu , Fujita Kahee , Koga Toshitaka 
Published: July 2006

Abstract
3-O-(2-Naphthylsulfonyl)-γ-cyclodextrin was prepared together with 2-O-(2-naphthylsulfonyl)-γ-cyclodextrin by a reaction of γ-cyclodextrin with 2-naphthalenesulfonyl chloride in aqueous CH3CN, isolated, and structurally determined.
Characterization of the Surface Oxide Layer on Iron Particles for Magnetic Recording by Mössbauer Spectrometry
Authors: Makishima Akio , Yamamoto Yukihiro , Watanabe Kohji 
Published: July 2006

Abstract
The average valency of iron in the oxide layer on iron particles for magnetic recording and the saturation magnetization of the oxide layer were estimated to be 2.8 and 39 emu g−1, respectively, by examining the Debye temperature and the recoilless fraction of oxide layer which were calculated with the Mössbauer parameters.
PPS Preparation. A Kinetic Study and the Effect of Water on the Polymerization
Authors: Ito Masato M , Onda Masahiro , Ona Seiichi , Inoue Hakuai 
Published: July 2006

Abstract
A kinetic study on poly (p-phenylene sulfide) formation from p-dichlorobenzene (1) and sodium sulfide reveals that the initiation rection is first order with respect to 1 and sodium sulfide, respectively. Reaction on the surface of solid sodium sulfide has proved to be negligible when the reaction is carried out in the presence of the solid. The time course of the concentration of 1 and its dimer can be explained with a simplified eight step kinetic model for the initial stage, in which each of the step is firest order with respect to the reactant in concern. Kinetic parameters for each of the steps were estimatied. Increase in [Na2S]/[1] ratio causes the increase both in polymer yield and in the degree of polymerization. Presence of a small amount of water enhances cosiderably the rate of polymerization and increases the polymer yield, but the highest degree of polymerization was observed in the presence of water approximately equimolar to 1.
Chemistry of Organic Eutectics: p-Phenylenediamine–m-Nitrobenzoic Acid System Involving the 1:2 Addition Compound
Authors: Rai U S , Mandal K D 
Published: July 2006

Abstract
The phase diagram of p-phenylenediamine–m-nitrobenzoic acid system, determined by the thaw-melt method, show the formation of two eutectics and a 1:2 addition compound. The linear velocity of crystallization of pure components, eutectics and addition compound, measured by determining the rate of movement of growth front in a capillary, suggests that crystallization data obey the Hillig–Turnbull equation. Using experimental values of heats of fusion, determined by the DTA method, entropy of fusion, heat of mixing and excess thermodynamic functions were calculated and the results are explained on the basis of cluster formation in the melts. Microscopic studies reveal that the eutectics have different characteristics microstructures as compared to those of parent components. X-Ray diffraction data suggest that there is preferential ordering of atomic planes in the formation of the eutectics.
The Kinetics and Mechanism of the Decomposition Reaction of the Bis(oxalato)manganese(III) Complex in an Aqueous Solution
Authors: Kimura Masaru , Ohota Miwako , Tsukahara Keiichi 
Published: July 2006

Abstract
The kinetics and mechanism of the decomposition of the bis(oxalato)manganese(III) complex ion ([Mn(ox)2]−) were studied in acid solution in the absence and in the presence of oxygen at temperatures from 10 to 35°C. The decomposition reaction of [Mn(ox)2]− in the absence of oxygen was described by the first-order rate law of −d[[Mn(ox)2]−]/dt=kobsd[[Mn(ox)2]−], where the observed rate constant, kobsd, increased proportionally with the increasing hydrogen-ion concentrations, being expressed as kobsd=k[H+] in the [H+] range of 0.006–0.1 M. The enthalpy and entropy changes of activation(ΔH\eweq and ΔS\eweq) were 73.4±2.0 kJ mol−1 and −8.6±0.2 J K−1 mol−1 respectively. The rate of the decomposition of [Mn(ox)2]− decreased greatly upon the addition of a radical scavenger for CO2\ewdot such as [Co(NH3)6]3+, [CoCl(NH3)5]2+, or molecular oxygen. In the presence of oxygen, the rate deviated greatly from the first-order rate law. On the other hand, the addition of [Co(NH3)6]3+ or [CoCl(NH3)5]2+ in the absence of oxygen did not change the first-order rate law, but did decrease the rate of reaction up to 40% of that in the absence of the radical scavenger. The mechanisms for the decomposition reaction of [Mn(ox)2]− are discussed in the light of the results obtained.
Liquid/Solid Extraction of Acetylacetone Chelates with Supercritical Carbon Dioxide
Authors: Saito Norio , Ikushima Yutaka , Goto Tomio 
Published: July 2006

Abstract
The solubilities of the acetylacetone chelates in supercritical CO2 (SC-CO2) at 333 K and 9.8–29.4 MPa were strongly influenced by the extraction pressure, and by the nature of the metals and the number of acetylacetone ligands in the chelates. It was found that acetylacetone chelates could be extracted selectively by SC-CO2 treatment because of significant differences in their solubilities in SC-CO2.
Dideoxygenation on the 3′,4′-Positions of an α-Linked Disaccharide Derivative: A Key Intermediate for New Aminoglycoside Synthesis
Authors: Hayashida Mitsuo , Sakairi Nobuo , Kuzuhara Hiroyoshi 
Published: July 2006

Abstract
A 2′,6′-diamino-1,6-anhydro disaccharide derivative (6) was prepared from maltose. The 3′,4′-diol system of 6 was successfully converted into the 3′-ene system by application of the Corey–Winter procedure, giving the hex-3′-enopyranose derivative (8). Catalytic hydrogenation of 8 gave the dideoxy derivative, a key intermediate for the synthesis of a new aminoglycoside.
Adsorption Behavior of Some Metal Ions onto Octadecylsilica Gel in the Presence of Acetylacetone
Authors: Kato Masanao , Shimofuruya Hiroshi 
Published: July 2006

Abstract
Adsorption of 11 metal acetylacetonate complexes onto an octadecylsilica(ODS) gel from an aqueous solution was measured as a function of pH. It was found that the pH dependencies regarding adsorption are almost consistent with those of a solvent-extraction system, except for Zn(II) which is unextracted into benzene. Plots of the adsorption ratio against pH indicates the 1:1 complexes are adsorbed onto ODS gel, except for Al(III) whose composition is 1:2.
Photochromism of a Furylfulgide, 2-[1-(2,5-Dimethyl-3-furyl)ethylidene]-3-isopropylidenesuccinic Anhydride in Solvents and Polymer Films
Authors: Yokoyama Yasushi , Hayata Hirofumi , Ito Hiroshi , Kurita Yukio 
Published: July 2006

Abstract
The quantum yields of the photochromic reaction between (E)- and (Z)-2-[1-(2,5-dimethyl-3-furyl)ethylidene]-3-isopropylidenesuccinic anhydride and the cyclized valence isomer were determined in various solvents and polymers. In both media the ring-opening quantum yield (ΦCE) depended on the dielectric constant of the media. In some polymer films, ΦCE were larger, and the cyclization quantum yield (ΦEC) and olefinic isomerization quantum yields (ΦEZ) and (ΦZE) were smaller than those in the corresponding solvents.
Cis Selective Wittig Olefination of α-Alkoxy Ketones and Its Application to the Stereoselective Synthesis of Plaunotol
Authors: Inoue Seiichi , Honda Kiyoshi , Iwase Norimichi , Sato Kikumasa 
Published: July 2006

Abstract
Several Wittig olefinations between α-heterosubstituted acetones and a phosphorus ylide were investigated concerning the product stereoselectivity. Benzyloxyacetone and tetrahydropyranyloxyacetone furnished trisubstituted (Z)-olefins exclusively. The stereoselective preparation of oxygenated acyclic terpenoids was practical by use of the direct Wittig olefination toward α-alkoxy ketones, and it facilitated a total synthesis of plaunotol from geraniol derivatives in short steps with high stereoselectivity.
Photochromic Properties of Unsymmetric Mono- and Bis(phenylazo)naphthalenes
Authors: Yoshida Katsuhira , Koujiri Tetsunao , Horii Taeko , Kubo Yuji 
Published: July 2006

Abstract
To utilize the reversible photochromic system of phenylazonaphthalenes in a design of functional molecule, the photochromic behaviors of various substituted phenylazonaphthalenes have been investigated. Introduction of substituents onto ortho positions with respect to the azo group retarded the rate of thermal cis-to-trans isomerization. The retardation effects were greatly dependent on both the number and position of the ortho substituents. To investigate the reterdation effects of ortho substituents, the activation parameters were determined; the results suggest that the steric hindrance among the ortho substituents and the two nitrogen lone pairs of the azo group becomes far more severe in an inversional transition-state than in the ground cis-state, which leads to the remarkable slow cis-to-trans isomerization. On the basis of the kinetic data of various phenylazonaphthalenes, the complicated isomerization behaviors of unsymmetric bis(phenylazo)naphthalenes have been elucidated.
Catalysis of Pd(II)-Catalyzed Acetalization of Alkenes with Diols
Authors: Hosokawa Takahiro , Ataka Yoshiharu , Murahashi Shun-Ichi 
Published: July 2006

Abstract
Alkenes bearing electron-withdrawing substituents are catalytically acetalized with 1,3-propanediol only by the use of PdCl2(MeCN)2 catalyst under O2 atmosphere. When a combination of BiCl3 and LiCl is used as co-catalyst, the acetalization proceeds effectively. These results indicate that a hydroperoxopalladium(II) species is most likely an active catalyst in the present reaction.
Dual Channels for Nucleophilic Displacements on Benzoyl Chlorides: Tetrahedral and Trigonal-Bipyramidal Transition States
Authors: Yamabe Shinichi , Koyama Tetsuji , Minato Tsutomu , Inagaki Satoshi 
Published: July 2006

Abstract
Nucleophilic substitutions on carbonyl carbons initiated by Cl−, Ph–CO–Cl+Cl−→Cl−+Ph–CO–Cl, were studied with ab initio MO calculations. Two transition states (TS’s) were found. One is the “tetrahed-ral” TS caused by the π attack of the nucleophile. The other is the “trigonal-bipyramidal” TS initiated by the σ attack. The coexistence of two TS’s is in accord with the proposals of Bentley and Cevasko et al. based on kinetic analyses. Two independent reaction paths are interpreted in terms of the frontier-orbital theory.
Novel Nematogenic Benzene Derivatives: N,N′-Dialkanoyl-2,5,6-trimethyl-4-alkanoyloxy-1,3-benzenediamines
Authors: Kawada Hiromitsu , Matsunaga Yoshio 
Published: July 2006

Abstract
A series of N,N′-dialkanoyl-2,5,6-trimethyl-4-alkanoyloxy-1,3-benzenediamines has been synthesized. The mesophases appearing in the octanoyl to octadecanoyl derivatives adopt a schlieren texture and are transformed into isotropic liquids, with enthalpy changes as small as from 1 to 4 kJ mol−1. Their X-ray diffraction patterns consist of only two diffuse peaks, fully confirming that the phases are nematic in type. The spacing deduced from the inner diffraction peak is markedly shorter than the molecular length and is similar to the spacings, d100, found for the hexagonal disordered columnar phases exhibited by closely-related benzene derivatives. This is strong evidence for the alignment with their normals to the average molecular planes parallel. In other words, the mesophase is classified as discotic even though the molecular shape is far from disk-like. Another viscous birefringent phase is found below the nematic phase when the molecule carries octanoyl to hexadecanoyl groups.
The Total Synthesis of 8β-Hydroxycycloaraneosene by Means of an Eight-Membered Ring-Formation via a Lewis Acid-Catalyzed Ene Reaction. Confirmation of Its Natural Occurrence
Authors: Kato Nobuo , Wu Xue , Tanaka Shinya , Takeshita Hitoshi 
Published: July 2006

Abstract
An improved eight-membered ring closure by means of a Lewis-acid-catalyzed ene reaction was applied to the synthesis of cycloaraneosene and its congener, “hydroxycycloaraneosene.” Comparisons of the NMR spectral data of the synthetic and natural compounds established that the natural product possesses an 8β-hydroxy structure, not the originally proposed 9α-hydroxy one.
Effect of Azoles as a Nucleotide Activating Group on Uranyl (Vl)-Ion Catalyzed Synthesis of Oligoadenylate in Aqueous Solution
Authors: Sawai Hiroaki , Shibusawa Takashi , Kuroda Kensei 
Published: July 2006

Abstract
Various adenosine-5′-phosphorazolides were prepared from adenosine-5′-phosphate and azoles such as 2-methylimidazole, 4-methylimidazole, 1,2,4-triazole, 3-nitro-1,2,4-triazole, benzimidazole and 2-methylbenzimidazole. The adenosine-5′-phosphorazolides obtained were then polymerized in neutral aqueous solution using uranyl(VI) ion as a catalyst. Oligoadenylates up to the hexadecamer with 2′-5′-internucleotide linkage were formed in high yields under the optimum condition. The azoles worked as adenylate activating group, and had a large effect on the rate of polymerization, the yield and the chain length of the resulting oligonucleotides. Imidazolides showed the moderate reactivity and gave oligoadenylates of the longest chain length. From the phosphortriazolides, only short-chained oligoadenylates were obtained, as they are susceptible to the hydrolysis. Polymerization and hydrolysis reaction of the benzimidazolides were retarded.