bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solution Behavior of Sodium Dodecyl Sulfate in Methanol
Authors: Miyata Isamu , Takada Akira , Yonese Masakatsu , Kishimoto Hiroshi 
Published: July 2006

Abstract
The electric conductivities of sodium dodecyl sulfate (SDS) in methanol and water were measured at 298 K in a concentration range up to 10 mmol dm−3. The values of the limiting molar conductivities of SDS, Λ0, in methanol and water were estimated to be 81.5 and 74.0 S cm2mol−1, respectively, and compared with each other. From those values and the values of NaCl in both solvents, the limiting molar conductivities of dodecyl sulfate ion in methanol and water were estimated to be 36.27 and 23.90 S cm2mol−1, respectively. Also, the vapor-pressure depression of SDS in methanol was measured at 298 K in the concentration range up to 42 mmol kg−1. From the results, and according to the theory regarding strong electrolytes, the mean ionic activity coefficient, γ±, of SDS in methanol at 298 K was calculated. Further, the solubility and heat of solution of SDS in methanol at various temperatures and at 298 K, respectively, were measured. From a thermodynamic analysis of these results, the theoretical relation between lnγ± and m was obtained over the range of temperatures 285–295 K.
Cooperative Effect of Lipophilic Amine and Neutral Crown Ether on Potassium Ion Active Transport through a Chloroform Membrane
Authors: Yoshida Shoichiro , Watanabe Tadashi 
Published: July 2006

Abstract
A competitive proton-driven transport of alkali metal ions with co-transported picrate anion was investigated in a chloroform membrane system containing either dicyclohexano-18-crown-6 (DCl8C6), octadecylamine (C18NH2), or a DCl8C6/C18NH2 mixture as cooperative carrier. The cooperative carrier effectively transported K+ against its concentration gradient between the two aqueous phases. The DCl8C6 alone, though being a proton-unionizable carrier, also mediated the uphill transport of K+ when the receiving phase was strongly acidic. The mechanisms for these transport behaviors are discussed referring to additional data on the partitioning of species at membrane/aqueous phase interfaces.
Restricted Rotation Involving the Tetrahedral Carbon. LX. peri-Substituent Effect on the Rotational Barrier of the 9-Methyl Group in Several Triptycene Derivatives
Authors: Yamamoto Gaku , Oki Michinori 
Published: July 2006

Abstract
Dynamic 1H NMR study was made on several 1-substituted 8,13-dichloro-9-methyltriptycenes and 8-chloro-13-fluoro-9-methyltriptycenes to examine the effect of the peri-substituents on the rotational barrier of the 9-methyl group. The rotational barrier height increases in the expected order as the 1-hydrogen is replaced by a bulkier group up to CH3, but shows a very low value when a t-butyl group is introduced into 1-position to show that destabilization of the ground state by the bulky t-butyl group exceeds that of the transition state for rotation.
Molecular Dynamics Calculation for the Complexes of a Macrotricyclic Receptor with Organic Substrates
Authors: Kimoto Hiroki , Saigo Kazuhiko , Kihara Nobuhiro , Ohno Mami , Hirano Tsuneo , Hasegawa Masaki 
Published: July 2006

Abstract
Molecular dynamics calculation was performed in order to obtain structural information about the complexes of a macrotricyclic receptor (1), which has crown ether and cyclophane subunits as binding sites, with organic substrates, ω-(phenylalkyl)ammonium picrates (2; the methylene number, n=4, 5, 7), taking account of solvent effect. The resulting equilibrium structures were in good agreement with experimental data; among the three complexes, the complex of 1 with 2 (n=5) gave the largest stability constant. Furthermore, the quantitative evaluation of the difference in Gibbs free energy between two complexes, calculated by the perturbation method, was also consistent with the experimental data.
Some Properties of Cyclopropenone Oximes under Beckmann Reaction Conditions
Authors: Yoshida Hiroshi , Yoshida Keisuke , Totani Hiroyuki , Ogata Tsuyoshi , Matsumoto Kiyoshi 
Published: July 2006

Abstract
The reaction of diphenylcyclopropenone oxime (1a) with acetyl or tosyl isocyanate, carboxylic anhydrides, or nitrohalobenzenes yielded the cyclopropenone O-substituted oxime derivatives. Treating with thionyl bromide and chloride 1a gave 3-haloacrylonitriles. Whereas 1a as well as other cyclopropenone oximes, were stable under acidic conditions, heating in methanolic sodium hydroxide gave the ring-opened α,α-dimethoxyketones oximes.
Synthesis of Pyrrole Derivatives from 5,6-Dihydro-4H-1,2-oxazines via Reductive Deoxygenation by Use of Fe3(CO)12
Authors: Nakanishi Saburo , Otsuji Yoshio , Itoh Keiji , Hayashi Nobuaki 
Published: July 2006

Abstract
α-Bromooximes such as α-bromoacetophenone oxime and ethyl 3-bromo-2-(hydroxyimino)propanoate react with enamines to give 5,6-dihydro-4H-1,2-oxazines in good yields. Dihydro-1,2-oxazine derivatives are also obtained by the reaction of α-bromooximes with vinyl ethers and silyl enol ethers in the presence of Na2CO3. Dihydro-1,2-oxazines can be converted into pyrrole derivatives via reductive deoxygenation by treating with Fe3(CO)12 in moderate to excellent yields. Iron carbonyl complexes other than Fe3(CO)12 are also effective for the pyrrole-forming reaction. The efficiency of the complexes for this reaction decreases in the order: Fe3(CO)12&gt;&gt;Et3NH[HFe3(CO)11]&gt;Fe2(CO)9&gt;&gt;Fe(CO)5. Both of the dihydro-1,2-oxazine- and pyrrole-forming reactions can be carried out in a single flask, giving pyrrole derivatives in good yields.
Optical Resolving Ability of 3,5-Dimethylphenylcarbamates of Oligosaccharides and Cyclodextrins
Authors: Aburatani Ryo , Okamoto Yoshio , Hatada Koichi 
Published: July 2006

Abstract
3,5-Dimethylphenylcarbamates of oligosaccharides and cyclodextrins were synthesized and their chiral recognition abilities were evaluated as chiral stationary phases for high-performance liquid chromatography. In case of the carbamates of linear maltooligosaccharides, the optical resolution abilities of 4–7-mer were similar to each other and were not so different from the ability of amylose tris(3,5-dimethylphenylcarbamate). The chiral recognition abilities of the carbamates of cellooligosaccharides were lower than that of the cellulose tris(3,5-dimethylphenylcarbamate). The intensities of the CD spectra of the cellooligosaccharide derivatives were smaller than that of the cellulose derivative. These results suggest that the less ordered structure of the cellooligosaccharide derivatives may be correlated to the lower chiral recognition. On the other hand, 3,5-dimethylphenylcarbamates of cydodextrins showed quite different optical resolution abilities from that of amylose tris(3,5-dimethylphenylcarbamate), probably because of a quite different high-order structure.
Boron Analogues of α-Amino Acids: Synthesis and Characterization of Some Amine-methoxycarbonylboranes and Trimethylamine-(alkylcarbamoyl)boranes
Authors: Das Mrinal K , Mukherjee Purnendu , Roy Sarbari 
Published: July 2006

Abstract
Syntheses of a number of amine-methoxycarbonylboranes R2−nHnN·BH2COOCH3 and trimethylamine-(alkylcarbamoyl)boranes, Me3N·BH2CONRR′ are reported. Both types of compounds have been prepared by condensing appropriate amine-carboxyboranes with methanol and an amine, respectively, in presence of dicyclohexylcarbodiimide, and have bean characterized by elemental analysis, IR and NMR (1H and 11B) spectra.
Anodic Voltammetry of Hydroxylamine at Rotating Disc Electrode of Platinum
Authors: Sultan Salah M , Bishop E 
Published: July 2006

Abstract
Hydroxylamine has been examined by anodic voltammetry at platinum electrode in sulphuric acid media. Obedience to Levich relationship was shown at platinum electrode in 0.01 M sulphuric acid concentration in the range 2.0×10−4 to 1.0×10−3 M, (M=mol dm−3). Electrode kinetics parameters have been evaluated and a possibility of the reaction mechanism path is suggested.
Substituent Effects on the Electronic Absorption and MCD Spectra of Five- and Six-Coordinate Nitrosyl(tetraphenylporphyrinato)iron(II) Complexes
Authors: Yoshimura Tetsuhiko 
Published: July 2006

Abstract
Electronic absorption and MCD spectra of five- and six-coordinate nitrosyl iron(II) complexes of a series of tetrakis(para-substituted phenyl)porphyrins have been investigated in order to elucidate the cis-effect of para-substituents. The MCD spectroscopy was more sensitive to the substituent effect than the electronic absorption spectroscopy.
Cis/Trans Isomerization of Thioindigo Derivatives Adsorbed on Silica Gel Modified with Octadecyl Groups
Authors: Fukunishi Koushi , Tatsuma Masahiko , Fatah Ur Rahman S M , Kuwabara Masaki , Yamanaka Hiroki , Nomura Mototeru 
Published: July 2006

Abstract
A photochromic behavior based on the cis/trans isomerization of thioindigo derivatives (I) adsorbed on alkylated silica gel is described. The reversible cis/trans isomerization of I in the adsorbed state can be induced by irradiation, and the signal is read out as fluorescence. The thermal cis-to-trans isomerization of I adsorbed on modified silica gel is extremely slow, compared with that obtained on untreated silica gel.
Temperature Effect of the High-Pressure Diels–Alder Reaction of Tropone with Acrylonitrile
Authors: Li Zhi-Hong , Mori Akira , Takeshita Hitoshi 
Published: July 2006

Abstract
The high-pressure (to 10000 bar) Diels–Alder reaction of tropone with acrylonitrile showed temperature-dependent product distributions: at 80 °C, the product distribution was very similar to that obtained under atmospheric pressure to give four products, among which 9-endo-cyanobicyclo[3.2.2]nona-3,6-dien-2-one, in 38% yield, was the major product, while at room temperature there were only three products, i.e., 8-endo-, 9-endo-, and 9-exo-cyano derivatives. The absence of the 8-exo-cyano derivative might be due to an electrostatic repulsive interaction of cyano and carbonyl groups in the transition state geometry.
Synthesis and Conformational Properties of 2-Carboxy-15-crown-5 and Its Cation Complexes
Authors: Takahashi Toshio , Mallen Jesus , Lorenzo Dalia , Khanna Raj K , Nishikawa Masanori , Gokel George W 
Published: July 2006

Abstract
2-Carboxy-15-crown-5 has been prepared by potassium permanganate oxidation in modest yield. Its native conformation has been assessed by using infrared, NMR, and both MM2′ and MNDO calculations. Neutral cation complexes (of the form crown-COOH.MX) of this macrocycle with NaCl, NaBr, NaI, KCl, and CaCl2 have been prepared and studied. It is concluded that the carbonyl oxygen atom is a donor for the ring bound cation, an observation supported by the calculated lowest energy conformation of the non-complexed macrocycle.
Synthesis and β-Lactamase Inhibitory Activity of 3-Cyano-3-cephem Derivatives
Authors: Nishimura Shintaro , Yasuda Nobuyoshi , Sasaki Hiroshi , Matsumoto Yoshimi , Kamimura Toshiaki , Sakane Kazuo , Takaya Takao 
Published: July 2006

Abstract
Two new 3-cyano-3-cephem derivatives, potassium 3-cyano-3-cephem-4-carboxylate (2) and potassium 7α-phenylacetamido-3-cyano-3-cephem-4-carboxylate (3), were prepared from 7β-aminocephalosporanic acid. Compounds 2 and 3 showed only weak β-lactamase inhibitory activity in contrast to sodium 7α-[(1R)-1-hydroxyethyl]-3-cyano-3-cephem-4-carboxylate (1), indicating the important role of the 7α-(1-hydroxyethyl) substituent for β-lactamase inhibitory activity.
A Convenient Synthesis of 1,2,4-Tri-O-acetyl-5-deoxy-5-[(R)- and (S)-ethylphosphino and phenylphosphino]-3-O-methyl-α,β-d-xylopyranoses and Their Phosphinothioyl Derivatives
Authors: Hanaya Tadashi , Shigetoh Nobuyuki , Yamamoto Hiroshi , Armour Margaret-Ann , Hogg Alan M 
Published: July 2006

Abstract
1,2,4-Tri-O-acetyl-5-deoxy-5-[(R)- and (S)-ethylphosphinyl]-3-O-methyl-α,β-d-xylopyranoses (8a–d) were prepared from 5-deoxy-5-[(R)- and (S)-(ethoxy)ethylphosphinyl]-1,2-O-isopropylidene-3-O-methyl-α-d-xylofuranoses in two steps. Reduction of 8a–d and their 5-(phenylphosphinyl) congeners with trichlorosilane- triethylamine in benzene smoothly afforded the corresponding title 5-deoxy-5-phosphino-d-xylopyranoses (9a–d and 14a–d) without causing inversion of the ring-phosphorus atom. Treatment of 9a–d and 14a–d with sulfur in benzene efficiently provided the corresponding (phosphinothioyl)-in-ring d-xylopyranoses. Structural and conformational assignments of these newly obtained compounds were made on the basis of mass and NMR (1H and 31P) spectral data.
Michael Addition of Methyl 2-(Trimethylsilyl)propenoate with Organomagnesiums or Organolithiums Leading to 1:1 and/or 2:1 Adducts and Subsequent Peterson Olefination by Condensation with Carbonyl Compounds
Authors: Tanaka Junji , Kanemasa Shuji , Ninomiya Yusuke , Tsuge Otohiko 
Published: July 2006

Abstract
Michael addition of methyl 2-(trimethylsilyl)propenoate with organomagnesiums or organolithiums leads to 1:1 and/or 1:2 adduct anions which can be utilized in the subsequent step of Peterson olefination with carbonyl compounds. The 1:1/1:2 ratio depends upon the nature of donor molecules, the reaction conditions such as reaction temperature, polarity of solvent, and rate of addition of the acceptor molecule. Use of acceptors in excess results in the selective formation of 1:2 and/or 1:3 adducts.
Lewis Acid-Promoted Cross Aldol Reaction of Aldehydes with Ketones Utilizing 3-Methyl-2-phenyl-2-(2-oxoalkyl)benzothiazolines as an Enolate-Transferring Reagent
Authors: Chikashita Hidenori , Tame Shin-ichiro , Yamada Seiji , Itoh Kazuyoshi 
Published: July 2006

Abstract
The treatment of a variety of 3-methyl-2-phenyl-2-(2-oxoalkyl)benzothiazolines with aldehydes in the presence of 2 equivalents of SnCl4 in dichloromethane at −78°C underwent a carbon–carbon bond cleavage at the 2-position of the benzothiazoline ring releasing an 2-oxoalkyl moiety followed by the concurrent aldol-type reaction with aldehydes to afford the corresponding β-hydroxy ketones. Among the Lewis acids examined, SnCl4 was found to be most effective, while a similar reaction employing trimethylsilyl trifluoromethanesulfonate as an electrophilic promoter mainly gave the corresponding aldol-condensation product. In the case of the reaction with 3-methyl-2-phenyl-2-(1-substituted 2-oxoalkyl)benzothiazolines, a diastereomeric mixture of α-substituted β-hydroxy ketones as cross aldol products was obtained and the anti preference was generally observed for reactions with the benzothiazolines possessing an aromatic ketone moiety in modest to poor selectivity ranging between 69:31 and 57:43. In contrast to this, the reaction of the benzothiazoline possessing an alkyl ketone moiety, 3-methyl-2-phenyl-2-(1-methyl-2-oxobutyl)benzothiazoline, with benzaldehyde showed syn preference in modest selectivity of 70:30.
The Kinetics of Oxidation of Formaldehyde at a Platinum Electrode in an Acid Solution
Authors: Matsui Hiroshi , Kunugi Akira 
Published: July 2006

Abstract
Three types of the retardation were found for the rate of oxidation of formaldehyde at a platinum electrode in 0.5 mol dm−3 sulfuric acid. These rate retardations are attributed to the blocking of individual reaction sites by strongly chemisorbed species, the inhibition of the pairing of adjacent sites indispensable for the oxidation of formaldehyde, and the accumulation of oxidation intermediates. The oxidation rate under conditions excluding these rate retardations was independent of the potential in the potential range of about 0.4–0.6 V vs. a reversible hydrogen electrode and corresponded to first-order kinetics with respect to the formaldehyde concentrations. These kinetic data are explained in terms of a slow adsorption of formaldehyde molecules.
ESR Studies of the Adsorption Behavior of Styrene–Methyl Methacrylate Copolymer at the Solid–Liquid Interface
Authors: Kobayashi Kazutoshi , Araki Kazuo , Imamura Yoshio , Endo Ryuichi 
Published: July 2006

Abstract
The conformation of the copolymer of styrene and spin-labeled methyl methacrylate adsorbed on nonporous silica from solution was investigated by the use of the ESR method. The attached segment fraction of methyl methacrylate, PMMA, in the copolymer was evaluated experimentally. The attached segment fraction of styrene, PST, and the total attached segment fraction, PTOT, in the copolymer were estimated by means of numerical calculations from the value of PMMA. The amounts of saturated adsorption, AS, were obtained as a function of the mole fraction of styrene in the copolymer. The AS values of the copolymers through the mole fractions of styrene of 0.8 increased slightly with the mole fraction of styrene. The AS values of the copolymers at the mole fractions of styrene in excess of 0.8 decreased steeply to that of the styrene homopolymer. The change in the AS values of the copolymers was explicable in terms of the changes in the values of the surface coverage and the values of PTOT. The adsorbed methyl methacrylate homopolymer had a flat conformation, whereas the adsorbed styrene homopolymer had a loopy conformation. When the styrene content in the copolymer increased, the adsorbed conformations of the copolymers varied gradually from the conformation of the methyl methacrylate homopolymer to that of the styrene homopolymer.
Diffusion of Polar and Nonpolar Molecules in Water and Ethanol
Authors: Tominaga Toshihiro , Matsumoto Shigetoshi 
Published: July 2006

Abstract
Interdiffusion coefficients of 1,2-butanediol, 1,4-butanediol, meso-erythritol, xylitol, mannitol, and myo-inositol in water, and of 1-butanol, 1,2-ethanediol, 1,2-butanediol, 1,4-butanediol, 1,2,3-propanetriol, water, and benzene in ethanol have been measured at concentrations close to infinite dilution and temperatures between 278 and 373 K. In water, activation energies are not sensitive to the solutes, decrease with increasing temperature, and are close to that for the self-diffusion of pure water. In ethanol the activation energy is largest for water and smallest for benzene. The quantity Dη⁄T (D, η and T are diffusivity, viscosity, and absolute temperature, respectively) is not sensitive to temperature in water, but shows strong dependence on the temperature for benzene and water in ethanol. Using the corrected Stokes–Einstein equation, the effective radii of the solutes were obtained in ethanol. Some differences in diffusion behavior in ethanol and water are discussed.
A Linear Relationship between the Glass Transition Temperature and Local Distortion of Calcium Gallate, Barium Gallate, and Calcium Aluminate Glasses
Authors: Nishida Tetsuaki , Ide Hiroshi , Takashima Yoshimasa 
Published: July 2006

Abstract
The isomer shift in the 57Fe-Mössbauer spectra of xCaO·(90−x)Ga2O3·10Fe2O3 (x=40–60) and xBaO ·(90−x)Ga2O3·10Fe2O3(x=65–70) glasses decreases gradually from 0.28 to 0.16 mm s−1 with increasing CaO or BaO contents. This indicates a formation of nonbridging oxygen atoms in the GaO4 and FeO4 tetrahedra. Large quadrupole splitting (Δ) values ranging from 0.98 to 1.24 mm s−1 indicate a noticeable distortion of the GaO4 and FeO4 tetrahedra. Mössbauer parameters of xCaO·(95−x)Al2O3·10Fe2O3 glasses (x=55–60) are comparable to those of the xCaO·(90−x)Ga2O3·10Fe2O3 glasses, suggesting that the local structures are essentially the same with each other. The glass transition temperatures (Tg) of the calcium gallate, barium gallate, and calcium aluminate glasses are 702–728, 580–583, and 750–773 °C, respectively. It is found that the Tg of several oxide glasses is proportional to the Δ, being expressed by Tg=aΔ+b, where “a” is 680 °C mm1 s and “b” is −180°C when the Fe3+ ions are present at substitutional sites of the network former (NWF). The “Tg–Δ rule” is also applicable to the Fe3+ ions present at interstitial sites, in which case “a” and “b” are 35°C mm−1 s and 260°C, respectively. These findings indicate that the Tg is primarily determined by the distortion of NWF–oxygen polyhedra.
Determination of Trace Metals Forming Large Molecular Complexes in Natural Waters as Estimated by Ultrafiltration/Liquid Chromatography/Atomic Spectroscopy
Authors: Kobayashi Kensei , Akagi Tasuku , Haraguchi Hiroki 
Published: July 2006

Abstract
Concentration of trace metals forming complexes with large organic molecules in natural waters have been determined. Natural water samples (sea water and lake water) were filtered through a membrane filter (pore size: 0.45 μm) just after sampling, and concentrated by ultrafiltration. The concentrated natural water samples were fractionated by high performance gel filtration chromatography, and metal ion concentration in each fraction was determined by inductively coupled plasma atomic emission spectrometry and/or by graphite furnace atomic absorption spectrometry. Concentration of zinc forming large molecular complexes (LMC) in sea water was 0.07 ngmL−1, and that in lake water was 0.06 ngmL−1. Copper, iron, vanadium, and molybdenum forming LMC in natural waters were also determined. The present results suggest the existences of LMC-forming metal ions, some of which may be metalloenzymes dissolved in natural waters.
Polarographic Behavior of Metal Ions in the Presence of Polyethylene Glycol in Potassium Chloride1
Authors: Kurotu Takuzo 
Published: July 2006

Abstract
The polarographic behavior of Cu(II), Pb(II), Tl(I), Sn(II), In(III), Cd(II), and Zn(II) was investigated in the presence of polyethylene glycol (PEG) in 0.1 mol dm−3 potassium chloride. PEG was adsorbed on mercury drops within the potential range from ca.−0.2 through −1.50 V vs. SCE, and shifted the half-wave potentials of Sn(II), In(III), Cd(II), and Zn(II) toward the negative direction, leaving the wave heights unchanged. On the other hand, the polarograms of Cu(II), Pb(II), and Tl(I) were not affected by the presence of PEG. Linear relationships between the wave heights for Cu(II), Pb(II), In(III), Cd(II), Zn(II), and their concentrations were obtained in the presence of PEG. Among these ions, the polarographic waves of In(III) and Cd(II), whose reduction potentials are very close together, became well separated in the presence of PEG. It is, therefore, possible simultaneously determine In(III) and Cd(II) in this medium. Interference between In(II) and Pb(II) was observed in freshly prepared solutions. It is, however, feasible to precisely determine both ions by using PEG as a reduction potential-shift reagent for In(III) in order to eliminate the interference.
Kinetics and Mechanism of the Oxidation of Ethyl Acetoacetate and Diethyl Malonate by Dodecatungstocobaltate(III)
Authors: Gupta Mala , Saha Swapan K , Banerjee Pradyot 
Published: July 2006

Abstract
The reactions of dodecatungstocobaltate(III) with ethyl acetoacetate (EAA) and diethyl malonate (DEM) have been studied in aqueous acidic medium at 60°C. A first-order dependence of rate on both the concentrations of oxidant and reductant is obtained and the reactions are catalyzed by alkali metal ions. The general rate law for the reactions is expressed as kobs=2(k0+[M+])[R] where k0 and k denote the spontaneous and catalyzed paths respectively and [R], the reductant concentration. For EAA oxidation the values of k0=(1.82±0.10)×10−4 dm3 mol−1 s−1 and kLi+=(2.23±0.09)×10−3dm6 mol−2 s−1, kNa+=(1.19±0.07)×10−3 dm6 mol−2 s−1, kk+=(1.01×0.02)×10−3 dm6 mol−2 s−1. The corresponding values for DEM are k0=(2.63±0.07)×10−5 dm3 mol−1 s−1 and kLi+=(2.11±0.07)×10−4 dm6 mol−2 s−1, kNa+=(9.13±0.25)×10−5 dm6 mol−2 s−1, kK+=(8.25±0.06)×10−5 dm6 mol−2 s−1. The less resonance stabilization of the protonated free radical species compared to the free radical obtained from the ester itself in the rate-determining step would cause a lowering in rate and this seems to explain the [H+]−1 dependence for the ester oxidations. A plausible mechanism considering an outer-sphere association between the complex and reductant has been suggested. The phenomenon of catalysis is explained by assuming an intermediate bridge formation via alkali metal ions between the reactants.