bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrolysis of Active Esters of Aliphatic Carboxylic Acids with Cyclic Dipeptide Catalysts Consisting of l-Histidine and Different Aliphatic α-Amino Acids
Authors: Masuda Yoshihiko , Tanihara Masao , Imanishi Yukio , Higashimura Toshinobu 
Published: July 2006

Abstract
The hydrolyses of a series of p-nitrophenyl carboxylates with different acyl chains were investigated at 25 °C, pH 7.8 using cyclic dipeptides[cyclo(–l- or d-Xyz–His–) consisting of l-histidine (l-His) and an α-amino acid (Xyz) with different aliphatic side chains] as catalysts. Consequently, cyclo(–d-Leu–l-His–) and cyclo(–d-Val–l-His–) were found to be specifically effective catalysts for the hydrolysis of p-nitrophenyl laurate. These trans (d-l-type) cyclic dipeptides were much more efficient catalysts than their diastereomers, and were more reactive than imidazole, despite the fact that the former are less basic than the latter. The conformation of the cyclic peptides in solution was investigated using proton magnetic resonance spectroscopy and the relationship between conformation and catalytic activity was investigated. Consequently, it was found that the hydrophobic interaction between a catalyst and a substrate and the stereochemical fit for the cooperation of functional groups in the intramolecular nucleophilic catalysis are very important in order to attain a highly efficient catalysis. It was also found that the functional groups should have a certain size and flexibility in order to realize an effective stereochemical fit between functional groups of catalysts and substrates.
Sodium Sulfate Mixed with Rare Earth Sulfates(Ln=Y and Gd) and Silicon Dioxide as a Solid Electrolyte for a Sulfur Dioxide Detector
Authors: Imanaka Nobuhito , Yamaguchi Yasuo , Adachi Gin-ya , Shiokawa Jiro 
Published: July 2006

Abstract
Sodium sulfate mixed with rare earth sulfates(Ln=Y and Gd) and silicon dioxide exhibits a Na2SO4-I-like phase as well as a small amount of silicon dioxide phase. The former phase is excellent in Na+ ion conduction. The electrical conductivity of the Na2SO4–Ln2(SO4)3–SiO2(Ln=Y and Gd) systems is considerably higher than that of pure sodium sulfate. When the Na2SO4–Ln2(SO4)3–SiO2(Ln=Y and Gd) sample is applied as a solid electrolyte for a SO2 gas concentration cell, the measured EMF is in good agreement with the calculated EMF for a SO2 gas concentration range from 0.1% (1000 ppm) to 23%, and 0.32% (3200 ppm) to 10%, respectively.
Oxidative Cyclization of 3-(3-Heterocycle-substituted 2-Propenoyl)tropolones
Authors: Honda Masaaki , Imafuku Kimiaki 
Published: July 2006

Abstract
3-[3-(2-Furyl)-2-propenoyl]- (2a), 3-[3-(2-thienyl)-2-propenoyl]- (2b), 3-[3-(3-thienyl)-2-propenoyl]- (2c), and 3-[3-(3-pyridyl)-2-propenoyl]tropolone (2d) were prepared by the condensation of 3-acetyltropolone with the corresponding heterocyclic aldehydes. The compounds 2a–d were oxidized with selenium dioxide to afford 2-heterocycle-substituted cyclohepta[b]pyran-4,9-diones, while oxidation with both alkaline hydrogen peroxide and 2,3-dichloro-5,6-dicyano-p-benzoquinone gave 2-(heterocycle-substituted methylene)-2H-cyclohepta[b]furan-3,8-diones.
Reaction of Substituted Benzaldehydes with Sodium Hydrogensulfide or Sodium Sulfide in Liquid Ammonia
Authors: Takikawa Yuji , Shimada Kazuaki , Minami Tetsuo , Sato Ryu , Takizawa Saburo 
Published: July 2006

Abstract
Reactions of substituted benzaldehydes with sodium hydrogensulfide in the presence of nitrobenzene, nitrosobenzene, or azobenzene in liquid ammonia produce the corresponding benzyl alcohols and benzamides. On the other hand, reaction of benzaldehyde with sodium sulfide produces benzyl alcohol and benzamide. A reaction mechanism has been proposed which involves benzaldehyde anion radical.
Solvent Effects on the Monomer-Dimer Equilibrium and Dimerization of the 1-Methyl-2-methoxycarbonylpyridinyl Radical
Authors: Shimoishi Hirami , Tero-Kubota Shozo , Ikegami Yusaku 
Published: July 2006

Abstract
Solvent effects on the hyperfine splitting constants, monomer-dimer equilibrium, and kinetic parameters of the dimerization of the 1-methyl-2-methoxycarbonylpyridinyl radical have been examined in detail, using methylcyclohexane, toluene, 2-methyltetrahydrofuran, acetone, and acetonitrile as the solvents. A comparatively large activation energy for the fast step in the two-step dimerization mechanism suggests strongly that the dimeric intermediate is the 2,2′-dimer of the radical, which subsequently rearranges to the stable 4,4′-dimer.
Mössbauer Study of 60Co γ-Ray Irradiated FexMg1−x(NH4)2(SO4)2·6H2O
Authors: Sakai Nobuhiko , Sakai Fumiko , Sekizawa Hisashi 
Published: July 2006

Abstract
The γ-ray radiolytic oxidation of Fe2+ ions in FexMg1−x(NH4)2(SO4)2·6H2O (x=1.0, 0.75, 0.56, 0.35, and 0.075) is studied by Mössbauer spectroscopy. For x≤0.75, a part of Fe2+ ions remain unoxidized even after heavy irradiation of 60Co γ-rays in contrast to the complete disappearance of Fe2+ ions for x=1.0. At least three kinds of Fe3+ ions are produced, and two of them order magnetically at liquid He temperature. Their saturated relative amount after heavy irradiation depends on the concentration of Fe, and is well explained by the random distribution probability of Fe and Mg ions among the six neighboring metallic sites around the Fe2+ ion.
The Distribution of Mercury, Arsenic, and Antimony in Sediments of Kagoshima Bay
Authors: Sakamoto Hayao 
Published: July 2006

Abstract
Mercury, arsenic, and antimony were determined in marine sediments collected from Kagoshima Bay, and their distribution was investigated. The contents of mercury, arsenic, and antimony in surface sediments were higher than those in the marine sediments of the open ocean. The average contents of mercury, arsenic, and antimony in surface sediments in the northern part of the bay were higher than in the southern part. The high-temperature sediments (about 200 °C) in the vicinity of a sea bottom fumarole, located at a depth of about 200 m in the northern part of the bay, showed abnormal concentrations of mercury, arsenic, and antimony derived from the fumarole gas; the contents of these components decreased sharply with an increase in the distance from the fumarole. A high degree of positive correlation was found among the contents of the three components (mercury, arsenic, and antimony) over the northern part of the bay. In contrast, no such correlation was observed in the southern part of the bay. This is in accord with the fact that volcanic activity is more vigorous in the northern than in the southern part of the bay.
DNA Sequence and Intramolecular Evolutionary Tree of Calmodulin Gene. Application of Maximum Likelihood Method
Authors: Iida Yôichi 
Published: July 2006

Abstract
DNA sequences of calmodulin genes taken from chicken and electric eel were examined to investigate the molecular evolution of its protein. One notable feature of the amino acid coding region of the gene is that it can be subdivided into four domains having a similar amino acid sequence. In the present paper, an intramolecular evolutionary tree was constructed with the DNA sequences of the four domains.
Infrared Intensities in Methyl Chloride. III. Improvement of the Anharmonic Force Field and the Analysis of the Overtone and Combination Band Intensities
Authors: Kondo Shigeo , Koga Yoshinori , Nakanaga Taisuke 
Published: July 2006

Abstract
A recently obtained anharmonic ab initio force field of methyl chloride has been improved by the method of “predicate observations” using the observed values of the spectroscopic constants. The newly obtained force field was used to make re-analysis of the absorption intensities of the binary overtone and combination bands for CH3Cl and CD3Cl. Contribution from the electrical anharmonicity to the band intensities was estimated and compared with the ab initio result.
The Role of Aroyloxyl Radicals in the Formation of Solvent-derived Products in Photodecomposition of Diaroyl Peroxides. The Reactivity of Substituted Cyclohexadienyl Radicals and Intermediacy of ipso Intermediates
Authors: Takahara Shigeru , Urano Toshiyuki , Kitamura Akihide , Sakuragi Hirochika , Kikuchi Osamu , Yoshida Masayuki , Tokumaru Katsumi 
Published: July 2006

Abstract
Photolyses of bis(2-thiophenecarbonyl) peroxide (TPO) in benzene and toluene afforded, among free-radical products, biphenyl and dimethylbiphenyls, respectively, which were solely derived from the aromatic solvents. The yields of biphenyls depended upon the rate with which the radical intermediates were generated from the peroxides in sufficiently high concentrations for their dimerization. Photolyses of TPO and dibenzoyl peroxide in 1,3,5-trimethylbenzene afforded also a solvent-derived product, 2,3′,4,5′,6-pentamethyldiphenylmethane. Its formation provides clear evidence for participation of cyclohexadienyl radicals bearing the aroyloxyl group on the methyl-substituted ipso carbon atom.
Spectroscopic Studies on the Interaction of Polymeric In-chain Biguanide Biocide with Phospholipid Membranes as Probed by 8-Anilinonaphthalene-l-sulfonate
Authors: Ikeda Tomiki , Tazuke Shigeo , Bamford Clement H , Ledwith Anthony 
Published: July 2006

Abstract
Interaction of a highly effective polymeric biocide poly(hexamethylene biguanide hydrochloride)(PHMB) with phospholipid model membranes was investigated spectroscopically by using 8-anilinonaphthalene-l-sulfonate (ANS) as a fluorescent probe. PHMB enhanced the fluorescence intensity and shifted the maximum wavelength of fluorescence of ANS embedded in the negatively-charged liposome composed of egg PC and dicetyl phosphate, while it had only small effect on the neutral liposome composed of egg PC alone. These results were interpreted in terms of preferred binding of PHMB to negatively-charged species. The Benesi-Hildebrand type plots revealed that PHMB was adsorbed to a greater extent onto the negatively-charged membrane than onto the neutral membrane: the dissociation constants for the liposome–ANS complexes derived from the plots gave quantitative evidence for the enhanced binding of PHMB to the negatively-charged membrane. Diaminohexyl biguanide (DAHB), a corresponding monomer to PHMB, was found to have no significant effect on either the neutral nor the negatively-charged liposome, a finding probably related to the fact that DAHB is practically inactive.
Thermal Investigations of 1,4-Butanediamine Complexes of Nickel(II) in the Solid Phase
Authors: De Goutam , Chaudhuri Nirmalendu Ray 
Published: July 2006

Abstract
[NiL3]Cl2·H2O, [NiL2(H2O)2]Br2, and [NiL2(NCS)2] (L=1,4-butanediamine) have been synthesized and their thermal investigations have been carried out. [Ni2L3Cl4], [NiLCl2], [Ni4L3Br8], and [NiL(NCS)2] have been synthesized pyrolytically in solid phase by temperature arrest technique from their corresponding parent diamine complexes. All the parent tris and bis(diamine) complexes possess Oh geometry. [NiLCl2 possesses Td geometry, whereas, [NiL(NCS)2] possesses Oh though 1,4-butanediamine is chelated in both of these mono(diamine) complexes. Thiocyanate is found to be bridged in [NiL(NCS)2]. The probable mechanistic paths of decomposition of these diamine complexes have been propsoed.
Effect of Choline Derivatives on the Critical Micelle Concentrations of Anionic and Cationic Surfactants
Authors: Nakagaki Masayuki , Yokoyama Shoko 
Published: July 2006

Abstract
The decrease of the critical micelle concentration (cmc) of sodium dodecyl sulfate (SDS) was larger, while the decrease of that of dodecyltrimethylammonium chloride (DTAC) was smaller in the presence of choline derivatives than in the presence of NaCl at the same molar concentration.
The Magnetic Properties of the Ammonium Chloride Adducts of Copper(II) Chloroacetates
Authors: Emori Shuji , Haramaki Nobuyuki , Muto Yoneichiro 
Published: July 2006

Abstract
Various ammonium chloride adducts of copper(II) chloroacetate and copper(II) dichloroacetate were prepared. The variable-temperature magnetic susceptibilities of the dimethylammonium chloride adducts obey the Bleaney-Bowers equation, indicating the existence of the copper(II) acetate type of dinuclear moiety in their crystals. The effect of the counter cations on their magnetic moments was discussed.
Stereoisomers of trans- Dichlorocobalt(III) Complex with 1,7-Bis[(S)-2-pyrrolidinyl]-2,6-diazaheptane
Authors: Saburi Masahiko , Obata Shusei , Yamaguchi Motowo , Yoshikawa Sadao 
Published: July 2006

Abstract
The complex trans-[CoCl2(SS-pyht)]+ (SS-pyht=1,7-bis[(S)-2-pyrrolidinyl]-2,6-diazaheptane), prepared via the HCl treatment of Λ-β-[CoCO3(SS-pyht)]+, was found to take the (R,R) configuration with regard to the secondary nitrogen centers involving the central chelate. The isomer ratio of two diastereomers (trans(R,S) and trans(R,R)) was estimated at the equilibrium in methanol; (R,S)/(R,R)=10.4±2.6.
Synthesis of Chiral Crown Ethers Derived from trans, trans- and cis, trans-2,2′-Spirobiindan-1,1′-diols. Their Chiral Recognition and Complexation Properties
Authors: Naemura Koichiro , Ebashi Iwao , Nakazaki Masao 
Published: July 2006

Abstract
trans,trans-2,2′-Spirobiindan-1,1′-diol (1) was resolved as its (−)-ω-camphanic ester and the absolute rotation of the glycol 1 was determined. Two crown ethers and the acyclic analog were derived from (+)-1. Two crown ethers incorporating (+)-cis,trans-2,2′-spirobiindan-1,1′-diol were also prepared. Their chiral recognition properties in transport of methyl (±)-phenylglycinate hydrochloride and abilities to extract alkali metal picrates were investigated.
Solubilization of Alkyl p-Hydroxybenzoates in Hexa(oxyethylene) Dodecyl Ether Micelle
Authors: Goto Ayako , Endo Fumio , Higashino Takeo 
Published: July 2006

Abstract
An experimental study was made on the effect of the alkyl-chain length of alkyl p-hydroxybenzoates on their solubilization in nonionic micelle. The location of alkyl p-hydroxybenzoate in micelle and the change in micelle structure are discussed on the basis of the experimental result.
Adsorption of Hydrophobic Anions onto Phospholipid Membranes. The Effect of Membrane Surface Charge
Authors: Matsumura Hideo , Kakoki Hiroyuki , Furusawa Kunio 
Published: July 2006

Abstract
Hydrophobic adsorption of tetraphenylborate ions (TPB) onto lipid membranes were studied at different pH’s of aqueous phase by using lipid vesicles and monolayers. The amount of adsorbed TPB is much higher at pH 2 than at pH 7.4. This result indicates that the adsorption of hydrophobic ions is affected by the ionization state of surface polar groups of lipids, i.e., that the membrane surface potential plays a role in the adsorption of hydrophobic ions.
Synthesis of Pyrazolo[3,4-d]thiazoles
Authors: Thiruvikraman S V , Seshadri S 
Published: July 2006

Abstract
Several 5-substituted 1-phenylpyrazolo[3,4-d]thiazole derivatives have been synthesized by reaction of 5-amino-3-methyl-1-phenylpyrazole-4-thiol with different reagents.
Synthesis of 4-(1,5,9-Trimethyl-1-vinyl-4,8-decadienyl)catechol Dimethyl Ether
Authors: Anand Ramesh Chander , Ranjan Harish 
Published: July 2006

Abstract
Synthesis of 4-(1,5,9-trimethyl-1-vinyl-4,8-decadienyl)catechol dimethyl ether has been described utilizing Wittig reaction for the introduction of vinylic substituent at the quaternary carbon.
Study of Chemisorption and Hydrogenation of 2-Butenes on Platinum by Temperature-programmed Desorption
Authors: Tokitaka Shinji , Imamura Hayao , Tsuchiya Susumu 
Published: July 2006

Abstract
The temperature-programmed desorption (TPD) chromatograms of cis- and trans-2-butene from platinum black comprised three peaks (A, B, and C) with peak maxima at about 253, 373, and 573 K, respectively. Peak A was identified to be cis- or trans-2-butene and butane. Peaks B and C were from mixtures of cis- or trans-2-butene and butane with a trace amount of propylene. The propylene may have been formed from chemisorbed cis- or trans-2-butene by decomposition as the temperature was raised during the subsequent TPD. The reactivities of various types of chemisorbed hydrogen previously detected by TPD were also investigated with regard to the hydrogenation of 2-butenes. Two types of chemisorbed hydrogen, presumed to be present on the surface in the form of hydrogen atoms, chemisorbed on top of platinum atoms and in the bridge form of molecular hydrogen, were found to react with 2-butenes.
Rearrangement Approaches to Cyclic Skeletons. II. Structural Revision and Total Synthesis of (±)-Isosesquicarene, a [3–6] Fused-Ring Sesquiterpene
Authors: Uyehara Tadao , Yamada Jun-ichi , Kato Tadahiro , Bohlmann Ferdinand 
Published: July 2006

Abstract
The exo-7-(4-methyl-3-pentenyl) derivative of 3-carene (1a), the original structure reported for (±)-isosesquicarene, was synthesized starting from tropone, and it was found that 1a is not identical with natural isosesquicarene. The structure of isosesquicarene was reinterpreted as endo-7-(4-methyl-3-pentenyl) derivative of 3-carene (1b). The first total synthesis of (±)-isosesquicarene, 1b, has been accomplished on the basis of the photochemical transformation of 4-methylbicyclo[3.2.2]nona-3,6-dien-2-one into the 7-exo-methylbicyclo[4.1.0]hept-2-ene.
Preparation of LaNi5 Films and Effects of Hydrogen Absorption on Electrical Resistivities of the Films
Authors: Adachi Gin-ya , Sakaguchi Hiroki , Niki Ken-ichi , Nagai Hiroshi , Shiokawa Jiro 
Published: July 2006

Abstract
Thin films of LaNi5 have been prepared by means of a flash evaporation-deposition technique. Electric resistivity measurements on these films were carried out in an atmosphere of hydrogen. The films formed on quartz substrates were amorphous. Resistivities initially increased and then decreased during the absorption of hydrogen. During the desorption process, the reverse phenomenon was observed. The effect of the thickness of the films on the electric properties, during the hydrogen absorption-desorption process, was also studied. Sample pulverization could be avoidable by using films of less than 10 μm in thickness. The hydrogen contents of the films were determined by the quartz-crystal mass-monitoring (QCMM) method.
Convenient Preparations of 3,5-Disubstituted 1,2,4-Thiadiazoles by Oxidative Dimerization of Thioamides
Authors: Takikawa Yuji , Shimada Kazuaki , Sato Katsuyuki , Sato Shinichi , Takizawa Saburo 
Published: July 2006

Abstract
3,5-Disubstituted 1,2,4-thiadiazoles 2 were prepared by reaction of thioamides 1 with DMSO in the presence of such an electrophilic reagent as 1-methyl-2-chloropyridinium iodide, benzoyl chloride, acetyl chloride, hydrochloric acid, or trimethylsilyl chloride in organic solvents at room temperature in high yields. Thiadiazoles 2 were also obtained by reaction of 1 with NBS at room temperature in high yields. Thioamide S-oxides reacted with electrophilic reagents at room temperature to give the corresponding thiadiazoles 2 in high yields.
Preparation and Stereochemistry of Cobalt(III) Complexes Containing 2,11-Diphenyl-5,8-diaza-2,11-diphosphadodecane or (4S,9S)-4,9-Dimethyl-2,11-diphenyl-5,8-diaza-2,11-diphosphadodecane, (C6H5)(CH3)PCH2CHRNHCH2CH2NHCHRCH2P(CH3)(C6H5) (R=H or CH3)
Authors: Atoh Masamichi , Kashiwabara Kazuo , Fujita Junnosuke 
Published: July 2006

Abstract
New quadridentate ligands having two chiral phosphorus donor atoms, 2,11-diphenyl-5,8-diaza-2,11-diphosphadodecane (mp-PNNP) and (4S,9S)-4,9-dimethyl-2,11-diphenyl-5,8-diaza-2,11-diphosphadodecane (SS(C)-mp-PNNP), and their cobalt(III) complexes, trans-[CoCl2(mp- or SS(C)-mp-PNNP)]+ and cisβ-[Co(acac)(mp- or SS(C)-mp-PNNP)]2+ (acac=2,4-pentanedionate ion) were prepared and characterized. For both mp- and SS(C)-mp-PNNP, the dichloro and acac complexes formed three and four isomers, respectively, which were separated by column chromatography or fractional crystallization. No cisα-acac complex was yielded. The acac complexes of SS(C)-mp-PNNP formed a Λ-isomer stereoselectively. The absolute configurations of the phosphorus donor atoms in the SS(C)-mp-PNNP complexes were assigned on the basis of the 1H NMR and CD spectra. It was shown that the phosphorus donor atoms at chemically unequivalent coordination positions in cisβ-[Co(acac)(SS(C)-mp-PNNP)]2+ give remarkably different vicinal effects on the CD spectra.
Cerium or Ruthenium Catalyzed Oxidation of Alcohols to Carbonyl Compounds by Means of Sodium Bromate
Authors: Kanemoto Shigekazu , Tomioka Hiroki , Oshima Koichiro , Nozaki Hitosi 
Published: July 2006

Abstract
Sodium bromate has been found to be effective oxidant for oxidation of alcohols in the presence of cerium or ruthenium compounds in biphase reaction. Selective oxidation of secondary alcohols was performed in the presence of primary ones using cerium(IV) ammonium nitrate (CAN) or cerium(IV) sulfate (CS) as catalyst. For instance, treatment of 1,10-undecanediol with CS/NaBrO3 provided 11-hydroxy-2-undecanone in 82% yield. Ruthenium catalyzed biphase oxidation of alcohols with sodium bromate provided the corresponding aldehydes or ketones in good to excellent yields.
Quantitative Analysis of Effects of Substituted Phenols on Membrane Characteristics of Lecithin Liposomes
Authors: Miyoshi Hideto , Nishioka Takaaki , Fujita Toshio 
Published: July 2006

Abstract
The partition coefficient of a series of substituted phenols in a lecithin liposome/water system, P(L/W), and the effects of these compounds on the perturbation of liposomal membranes were quantitatively investigated using physicochemical molecular parameters. Partition behavior is primarily governed by hydrophobicity, represented in terms of the 1-octanol/water partition coefficient. Steric and electronic characters also were of significance. Potency in perturbation of liposomal membranes was governed by the degree of partitioning to the membrane and the steric bulkiness of the phenol. This kind of quantitative procedure was very helpful in investigating the effects of organic molecules on membrane characteristics.
Synthetic Photochemistry. XXXIV. Synthetic Strategy of 5-8-5-Membered Tricyclic Higher Terpenoids Based on the Condensation of Two Optically-Active Iridoids, C10-Synthons Obtained from Photo-Cycloadduct of Methyl 2,4-Dioxopentanoate–Isoprene, and Its Application to a Synthesis of the Basic Carbon Skeleton of Fusicoccane
Authors: Kato Nobuo , Nakanishi Kohji , Takeshita Hitoshi 
Published: July 2006

Abstract
One of the photocycloadducts obtained during methyl 2,4-dioxopentanoate to isoprene was converted to optically active iridoids. Using a CrCl2 reductive-coupling reaction, proper combinations of two kinds of enantiomeric iridoids, 1-iriden-7-al and 9-benzyloxy-7-chloro-1-iridene, produced versatile intermediates for various types of 5-8-5-membered tricyclic natural products. From one such product, fusicocca-2,8,10(14)-triene (1) was synthesized by sequential transformations.
Synthesis of 3-Arylmethyl-p-tropoquinones from 5-Alkoxy-2-(arylmethoxy)tropones via Homolytic Rearrangement and Oxidation
Authors: Takeshita Hitoshi , Mori Akira , Goto Yasutomo 
Published: July 2006

Abstract
The 3-(arylmethyl)-p-tropoquinones were synthesized by starting from the homolytic thermal rearrangement of 2-(arylmethoxy)-5-methoxytropones or 2,5-bis(arylmethoxy)tropones, followed by hydrolysis and oxidation. The half-wave potentials of these tropoquinones were determined by cyclic voltammetry. A remote substituent effect was observed for 3-(4-hydroxybenzyl)-p-tropoquinone, which may be attributable to intermolecular hydrogen bonding.