bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metal Ion-Selective Adsorbent Prepared by Surface-Imprinting Polymerization
Authors: Tsukagoshi Kazuhiko , Yu Kai Yu , Maeda Mizuo , Takagi Makoto 
Published: August 2006

Abstract
We propose a metal ion-imprinted microsphere as a new metal ion-selective adsorbent. Imprinted microspheres were prepared by seeded emulsion polymerization of divinylbenzene, styrene, butyl acrylate, and methacrylic acid. The imprinted structure was introduced on the carboxylated microsphere by surface-imprinting, in which the carboxyl groups were reorganized through complexation with metal ions on the surface and then fixed by crosslinking polymerization in their specific orientation. The Cu(II), Ni(II), and Co(II)-imprinted microspheres were obtained as submicron particles with average diameters of 0.55—0.60 μm. They were immediately used as a metal ion-selective adsorbent without any further treatment, such as grinding and sieving. The adsorption behaviors of metal ions (Cu(II), Ni(II), and Co(II)) were examined, and the imprinted effects were verified on Cu(II)- and Ni(II)-imprinted microspheres. The imprinted microspheres adsorbed the corresponding guest ion more effectively than did unimprinted ones.
Preparation and Characterization of Dithiocarbamatocobalt(III) Complexes Containing Phosphites, and Molecular Structures of cis-[Co{(CH3)2NCS2}2{P(OCH2)3CC2H5}2]BF4 and [Co(CH2CH2CH2CH2CH2NCS2){P(OCH3)3}4](BF4)2
Authors: Matsui Hayato , Kita Masakazu , Kashiwabara Kazuo , Fujita Junnosuke 
Published: August 2006

Abstract
Eleven new cobalt(III)–phosphite complexes of the [Co(S-S)P4]2+- and [Co(S-S)2P2]+-types were prepared, where S-S denotes bidentate dimethyldithiocarbamate (dtc), diethyldithiocarbamate (etdtc), and piperidyldithiocarbamate (pipdtc) ions, and P is 4-ethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane (etpb), trimethyl phosphite (pome), and triethyl phosphite (poet). The [Co(S-S)2P2]+-type complexes yielded the cis-isomer in the dark, but isomerized to the trans-isomer in solution by exposure of ultraviolet light. In the photo- and electrochemical reactions, it was inferred that the [Co(S-S)P4]2+-type complexes form a linkage-isomer in which a phosphite ligand is bound to Co(III) through the oxygen atom. Molecular structures of cis-[Co(dtc)2(etpb)2]BF4 (1) and [Co(pipdtc)(pome)4](BF4)2 (2) were determined by the X-ray diffraction method. Crystal data: complex 1, monoclinic, C2/c, a = 23.867(3), b = 17.583(2), c = 15.243(2) Å, β = 103.97(2)°, V = 6208(1) Å3, Z = 8, and R = 0.054 for 2533 reflections; complex 2, monoclinic, P21/c, a = 11.259(2), b = 23.865(4), c = 14.293(2) Å, β = 93.69(1)°, V = 3832.6(10) Å3, Z = 4, and R = 0.072 for 2539 reflections. The average Co–P bond distances of 2.171(1) Å in 1, and of 2.208(3) (trans to S) and 2.242(2) Å (trans to P) in 2 are a little shorter than those of analogous Co(III)–phosphine complexes.
AM1 Calculations for Regioselectivities and Reactivities Observed in Cyanation of 3-Substituted Pyrazine 1-Oxides with Trimethylsilyl Cyanide
Authors: Sakakibara Tohru , Ohwaki Yoshie , Sato Nobuhiro 
Published: August 2006

Abstract
Regioselectivities and reactivities previously reported in the reactions of 3-amino-, 3-cyano-, 3-mehoxy-, and 3-methoxycarbonylpyrazine 1-oxide with trimethylsilyl cyanide were corroborated on the basis of semiempirical molecular orbital calculations (AM method) involving an approach of a cyanide ion to the reactive sites.
High Reactivity of Heterocoerdianthrones (HCDs) in Photoperoxidation and Thermal Stability of Their Endoperoxides. Use of HCD as a Photosensitizer under Sunlight
Authors: Motoyoshiya Jiro , Masunaga Takashi , Harumoto Daisuke , Ishiguro Shigeru , Narita Susumu , Hayashi Sadao 
Published: August 2006

Abstract
The measured reactivity indices (β-values) of heterocoerdianthrones (HCDs) in self-sensitized photoperoxidation indicate a high reactivity toward singlet-oxygen. Such a high reactivity is not only due to an effective singlet-oxygen production due to the highly fluorescent character, but also due to a strained structure, as predicted by a molecular calculation. On the other hand, the large thermal stability of their endoperoxides (POs), revealed by the large activation energy in thermal decomposition, is also explained by considering the strained structure of the parent HCDs. As a prospect of solar synthesis, one of the HCD derivatives was applied to a photosensitizer for singlet-oxygen oxidation.
Peruvianosides A and B, Novel Triterpene Glycosides from the Bulbs of Scilla peruviana
Authors: Mimaki Yoshihiro , Ori Kazutomo , Sashida Yutaka , Nikaido Tamotsu , Song Lian-Gang , Ohmoto Taichi 
Published: August 2006

Abstract
Two new rearranged lanosterol trisaccharides, peruvianosides A (1) and B (2), were isolated from fresh bulbs of Scilla peruviana. Their structures were established mainly by extensive 2D NMR analysis. Peruvianoside A (1) showed an inhibitory activity on cyclic adenosine monophosphate (AMP) phosphodiesterase.
NAD(P)+–NAD(P)H Models. 81. Temperature-Dependent Stereospecificity in the Interconversion between Central and Axial Chiralities
Authors: Okamura Mutsuo , Mikata Yuji , Yamazaki Norimasa , Tsutsumi Akihiro , Ohno Atsuyoshi 
Published: August 2006

Abstract
In the oxidation of (4R)-Me3MQPH or (4R)-Me3PNPH with a series of 1,4-benzoquinone and its derivatives, the R/S ratio with respect to the axial chirality in the product, i.e., 11R-/11S- isomer ratio in Me3MQP+ or 7R-/7S- isomer ratio in Me3PNP+, changes depending on the reaction temperature as well as the reactivity of quinone. It is confirmed that kinetic R-preference stems from the entropy-control, whereas kinetic S-preference comes out of the enthalpy-control. The relative importance of enthalpy and entropy is discussed in terms of the earliness and lateness of the transition state at the initial electron-transfer step.
NAD(P)+–NAD(P)H Models. 82. Effect of Magnesium Ion on the Stereospecificity and Conformations at the Ground and Transition States of the Reaction
Authors: Okamura Mutsuo , Mikata Yuji , Yamazaki Norimasa , Tsutsumi Akihiro , Ohno Atsuyoshi 
Published: August 2006

Abstract
Conformations of 3-[methyl(α-methylbenzyl)carbamoyl]-1,2,4-trimethyl-1,4-dihydroquinoline ((4R)-Me3MQPH) in the presence and absence of magnesium ion have been studied. The major conformation at the ground state of Me3MQPH changes largely when this molecule forms a complex with a magnesium ion. The conformations at the ground and transition states will be discussed in relation to the stereospecificity of the reaction of this compound with quinones.
Formation of a Topochemically Photoreactive Mixed Crystal by Grinding and Its Mechanistic Interpretation
Authors: Kinbara Kazushi , Adegawa Yutaka , Saigo Kazuhiko , Hasegawa Masaki 
Published: August 2006

Abstract
A mixed crystal of ethyl and propyl α-cyano-4-[2-(4-pyridyl)ethenyl]cinnamate was formed in the solid state by simple grinding. The mixed crystal formation was ascertained by the change in the X-ray diffraction pattern upon grinding and by 1H NMR and HPLC analyses of the photoproducts. According to several attempts, it was concluded that a mechanical treatment was necessary for the formation of the mixed crystal phase. The kinetic data concerning the analysis of the topochemical photoproducts revealed that the following growth of the mixed crystal phase was triggered by each of the mixed crystal nuclei and that the growth of the mixed crystal phase was accelerated by either thermal annealing or exposure in humidity. During the early stage of mixed crystal growth, the growth rate was nearly proportional to the surface area of the nuclei of the mixed crystal.
Extraction Kinetics of Ytterbium with Salicylaldehyde n-Octanohydrazone into 1,2-Dichloroethane in the Presence of Both Tributyl Phosphate and Perchlorate
Authors: Odashima Tsugikatsu , Suzuki Teruhiko , Ishii Hajime 
Published: August 2006

Abstract
The kinetics of the solvent extraction of ytterbium(III) from aqueous media with a 1,2-dichloroethane solution of salicylaldehyde n-octanohydrazone (SOH or H2L) in the presence of both tributyl phosphate (TBP) and perchlorate have been studied at 25 ± 0.1 °C and an ionic strength of 0.2 M (1 M = 1 mol dm−3). The rate of extraction was first-order with respect to the concentrations of ytterbium(III) in the aqueous phase and SOH in the organic phase, inversely first-order with respect to the hydrogen-ion concentration and zero- and first-order with respect to the TBP concentration in the organic phase. Two mechanisms operate for this extraction, depending on the TBP concentration in the organic phase. One is a mechanism in which the formation of the first complex, [Yb(HL)]2+, between Yb3+ and HL− in the region of log [TBP]org &lt; −0.95 becomes the rate-determining step, and the other is that in which the formation of the first complex, [Yb(HL)(TBP)]2+, between [Yb(TBP)]3+ and HL− in the region of log [TBP]org &gt; −0.85 is the rate-determining step. The rate constant and activation parameters for the former reaction were calculated, but those for the latter one could not be determined.
Stability and Resonance Energy of Annulated 1-Azaazulenes
Authors: Kurihara Teruo , Kerim Ablikim , Ishikawa Sumio , Nozoe Tetsuo , Abe Noritaka 
Published: August 2006

Abstract
The stability and resonance energy of heterocycle-annulated 1-azaazulenes such as cyclohepta[4,5]pyrrolo[1,2-a]imidazole (5a) and 12-methoxy-5H-cyclohepta[4,5]pyrrolo[2,3-b][1,5]benzodiazepine (7) were elucidated by means of Aihara’s TRE and Gimarc’s TCS rule. These compounds are predicted to be aromatic with positive resonance energies and in conformity with the TCS rule.
The Reaction of 2,3-Dichloro-5,6-dicyano-p-benzoquinone with Benzofurans and Indoles
Authors: Tanemura Kiyoshi , Suzuki Tsuneo , Horaguchi Takaaki 
Published: August 2006

Abstract
The reaction of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) with 6-methoxy-3-methylbenzofuran gave carbon–oxygen adduct. The reaction in less polar solvents such as benzene and CH2Cl2 proceeds faster than that in more polar solvents such as THF and dioxane. In contrast, the reaction of DDQ with indoles gave carbon–carbon adducts. This reaction proceeds rapidly with increasing solvent polarity.
Synthesis and Structure of [3.3]Orthocyclophane
Authors: Wang Zhen-He , Usui Shuji , Fukazawa Yoshimasa 
Published: August 2006

Abstract
The title compound (1) was synthesized by desulfurization of 2,13-dithia[4.4]orthocyclophane. The molecular structure of 1 which has antiperiplanar arrangement of the two benzene rings was obtained by an X-ray crystallographic analysis. Molecular mechanics calculation using MM3 and our MMRS program has indicated that the anti structure found in crystal is the most stable conformer. Variable temperature 1H NMR measurement has disclosed that the contribution of the conformers other than the anti is negligible.
Syntheses and Electrical Properties of Organosilicon Polymers Containing Thiophene and Anthraquinone Units
Authors: Yi Sang Ho , Ohashi Syunsuke , Sato Hisaya , Nomori Hiroyuki 
Published: August 2006

Abstract
Organosilicon polymers containing thiophene and anthraquinone units in the main chain were synthesized using palladium catalyst. These polymers were soluble and showed a small UV absorption change by the substituents on the silicon atom. Some of the polymers exhibit cation doping (n-doping) by the electrochemical reduction, and this doping process seemed to depend on the kinds of substituents on silicon atom. These polymers showed electrical conductivity of 3 × 10−5 S cm−1 when doped with sodium naphthalenide.
Hexamethyltetralin Preparations Effect of Methyltrioctylammonium Chloride on Solvent/Olefin Interdependency
Authors: Frank Walter C , Miller Donna M 
Published: August 2006

Abstract
The use of quaternary ammonium salts as co-catalysts in the AlCl3 catalyzed cyclialkylation of p-cymene, 2-chloro-2methylpropane, and 3,3-dimethylbutene-1 is reported. The addition of co-catalyst, in solvents which normally give low yields of 1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene with 3,3-dimethylbutene-1, improves product yields, comparable with the best published 3,3-dimethylbutene-1 methodology. Addition of co-catalyst permits the use of more environmentally acceptable solvent systems than those in existing syntheses of the desired tetralin. The yield improvement is rationalized on the basis of improved reaction homogeneity, facile cleavage of Al2Cl6 by Cl− ion, and increased effective solvent polarity, promoted by addition of the quaternary ammonium salt co-catalysts.
Addition of quat co-catalysts to 3,3-dimethylbutene-1 based cyclialkylation systems did not increase rate, catalyst homogeneity or yield relative to a control (dichloromethane solvent). This suggests that the chlorinated hydrocarbon solvents normally used in this technology provide functions similar to that of quats in 2,3-dimethylbutene-1 based technology. These functions include the abilities to enhance AlCl3 solubility, increase the polarity of the reaction medium, and provide facile scission of Al2Cl6 to a more active catalytic species.
In reactions where 2,3-dimethylbutene-1 is substituted for 3,3-dimethylbutene-1, addition of co-catalyst improves reaction rate, catalyst homogeneity, and yield reproducibility in non-polar solvents when compared to the best published, 2,3-dimethylbutene-1 methodology.
Boron Compound as a Trapping Reagent of α-Hydroxy o-Quinodimethanes in the Diels–Alder Reaction
Authors: Shimada Satoru , Osoda Kazuhiko , Narasaka Koichi 
Published: August 2006

Abstract
The Diels–Alder reaction of methyl 4-hydroxy-2-butenoate and α-hydroxy o-quinodimethanes, generated from 1,2-dihydrobenzocyclobuten-1-ol derivatives by thermolysis, proceeds by the use of phenylboronic acid as a template. Boron reagents trap an α-hydroxy o-quinodimethane (5-methylene-6-(1-hydroxyalkylidene)-1,3-cyclohexadiene) generated photochemically from o-tolualdehyde and the Diels–Alder reaction with methyl 4-hydroxy-2-butenoate occurs to give the cycloadducts.
Dependence of the Lewis Acid-Induced Reaction of β-Stannyl Ketones upon Substitution Pattern: Cyclopropanation versus 1,2-Alkyl Migration
Authors: Fujiwara Jun , Sato Tadashi 
Published: August 2006

Abstract
3-Stannylcyclohexanones fully substituted at 2 and 3 positions underwent a 1,2-alkyl migration, along with the cyclopropanation. The balance of the reactions depended upon the steric environment and migratory aptitude of the alkyl groups.
Studies on Identification of Soot. V. Changes in Alkylbenzenes and Alkanes in Diffusion Flame
Authors: Takatsu Masahisa , Yamamoto Tadahiro 
Published: August 2006

Abstract
Changes in the diffusion flames of benzene, toluene, p-xylene, ethylbenzene, styrene, cumene, octane, and decane fuels were comparatively examined. Original fuels and dealkylation products were observed in the flames of the alkylbenzenes. Styrene was also found as an elimination product in the flames of ethylbenzene and cumene. The profiles of these products should depend on the structures of the side chains of the original alkylbenzenes. On the other hand, the two alkanes were easy to cleave and changed into smaller alkenes in the flame faster than the six other alkylbenzenes.
Synthesis and Properties of High Molecular Weight Polypeptides Containing Proline
Authors: Iizuka Yasuko , Uchida Chieko , Wakamatsu Kaori , Oya Masanao 
Published: August 2006

Abstract
High-purity N-carboxy-l-proline anhydride (N-carboxy-2-pyrrolidinecarboxylic acid anhydride) was synthesized. We used triethylamine instead of expensive Ag2O to remove HCl during the synthesis. Copolypeptides with a random sequence of l-proline (Pro) with glycine, l-alanine (Ala), l-α-aminobuthyric acid (Abu), l-Norvaline (Nva) or l-leucine (Leu) were synthesized by copolymerization of the corresponding N-carboxy-α-amino acid anhydrides in solution. Copolypeptides of Pro with Ala or Abu were partially soluble in water. However, the copolypeptides of proline with Nva or Leu with longer side chains were insoluble in water. The conformation of water-soluble copolymer at various pH was analyzed by circular dichroism (CD). The structures of the polypeptides in aqueous solution were almost independent of the pH, and were in a collagen-like conformation.
Unusual Effects of the Reaction Temperature on the Catalytic Activity of Rh/Active-Carbon for Ethylene Hydroformylation
Authors: Takahashi Nobuo , Sato Yoshinori , Uchiumi Takahiro , Ogawa Kazuo 
Published: August 2006

Abstract
The apparent activation energies for propionaldehyde and ethane formation from C2H4, CO, and H2 on a Rh/active-carbon catalyst, once used for a reaction at 453 K, were found to be 40 and 76 kJ mol−1, respectively. These values were much lower than those on a fresh Rh/active-carbon catalyst (120 and 125 kJ mol−1). Changes in the apparent activation energies were also induced by exposure of a fresh catalyst to CO at temperatures &gt; 433 K. Such catalytic behaviors, however, were not observed on a Rh/silica-gel catalyst. On the fresh Rh/active-carbon catalyst, the amount of adsorbed CO was found to be much more than that of adsorbed H2. The temperature-programmed desorption spectrum (TPD) of CO on the catalyst exposed to CO at 353 K after an H2 treatment at 573 K showed a single desorption peak at ca. 470 K; the value for the CO/Rh molar ratio was found to be 2.6. The amount of CO desorbed from the catalyst exposed to CO at 473 K, however, was found to be much less than that on the catalyst exposed to CO at 353 K. Namely, unusual effects of the reaction temperature on the catalytic activities, which were observed on the fresh Rh/active-carbon catalyst, were very closely related to changes in the amount of CO desorbed from the catalyst during TPD runs.
Structural Characterization and Catalytic Behavior of Al2O3-Supported Cerium Oxides
Authors: Haneda Masaaki , Mizushima Takanori , Kakuta Noriyoshi , Ueno Akifumi , Sato Yasunori , Matsuura Shinji , Kasahara Koichi , Sato Masayasu 
Published: August 2006

Abstract
Three kinds of supported cerium oxide catalysts were prepared by an impregnation and a sol–gel technique using aluminium tri-isopropoxide (AIP) and cerium(III) nitrate dissolved in ethylene glycol. One is cerium dioxide supported on alumina, and others are finely-divided nonstoichiometric cerium oxide and cerium aluminate crystallites dispersed on alumina, respectively. In order to investigate the relationship between the structure of cerium oxides and their catalytic behavior, these cerium oxides were subjected to “OSC” (oxygen storage capacity) measurements as well as kinetic studies for methane oxidation. The highest “OSC” was achieved on the finely-divided nonstoichiometric cerium oxides. Kinetics studies for methane oxidation resulted in the first order with respect to methane for all the catalysts, and nearly zero order with respect to oxygen on the cerium dioxide and cerium aluminate. While on the finely-divided nonstoichiometric cerium oxides a half order with respect to oxygen was obtained. On the basis of these results the structure and the catalytic behavior of cerium oxides was discussed in terms of the “OSC” associated with the oxygen vacancies existed in the finely-divided nonstoichiometric cerium oxides. A brief discussion was also made on Pd catalysts supported on these cerium oxides for methane oxidation.
Electrochemical Properties of Coenzyme Pyrroloquinolinequinone Using a Di-(4-pyridyl) Disulfide Modified Gold Electrode under Acidic Conditions
Authors: Nakamura Nobuhumi , Kohzuma Takamitsu , Suzuki Shinnichiro 
Published: August 2006

Abstract
The reversible electron transfer behavior of pyrroloquinolinequinone (PQQ) using a di-(4-pyridyl) disulfide (4-pyds) modified gold electrode was observed by cyclic voltammetry and the optically transparent thin-layer electrode (OTTLE) method under acidic conditions.
Facile Oxidative Coupling of Benzene by the Palladium(II) Acetate–Dialkyl Sulfide System
Authors: Fuchita Yoshio , Taga Masashi , Kawakami Mina , Kawachi Fumiko 
Published: August 2006

Abstract
By the palladium(II) acetate–dialkyl sulfide system, oxidative coupling of benzene has been achieved at 70 °C, where palladium(II) acetate alone is inactive for the reaction. Effects of alkyl group on the sulfides, molar ratios of sulfide to palladium(II) acetate, and atmosphere of oxygen have been investigated.
The Structure of Physalin P, a Neophysalin from Physalis Alkekengi
Authors: Kawai Masao , Matsumoto Akihide , Makino Bunsho , Mori Hideyuki , Ogura Toichi , Butsugan Yasuo , Ogawa Kiyoshi , Hayashi Mitsuo 
Published: August 2006

Abstract
The structure of physalin P, a constituent of Physalis alkekengi var. francheti, was determined to be 5α-hydroxy-6,7-didehydro-5,6-dihydroneophysalin B by spectroscopic study and chemical correlation with a known compound.
Beckmann Reaction of Oximes of 3a-Aryl-5,6a-diphenyl-3a,6a-dihydro-2H-furo[3,2-b]pyrrole-2,6(3H)-dione and Its Derivatives
Authors: Mataka Shuntaro , Suzuki Hiroshi , Sawada Tsuyoshi , Tashiro Masashi 
Published: August 2006

Abstract
In the reaction with pyrrolidine, the (Z)-6-oxime (2) of 3a-aryl-5,6a-diphenyl-3a,6a-dihydro-2H-furo[3,2-b]pyrrole-2,6(3H)-dione (1) gave the (Z)-oxime (3) in which the lactone ring was opened. (Z)-Oxime 3 isomerized on silica gel to give (E)-oxime 4. Treatment of 2 with tosyl chloride in aqueous ethanolic sodium hydroxide afforded 5-aryl-2-cyano-2-phenyl-1H-pyrrol-3(2H)-ones (7) in yields of 41—90%, while both 3a and 4a gave the pyrroline-ring-opened product 8 in moderate yields.
Intramolecular Through-Space Interaction in 2-(p-Methoxyphenyl)-2-butenyl 9-Phenanthrenecarboxylate as Evidenced by Their Isomerization Behavior
Authors: Itoh Hiroki , Senda Yasuhisa , Sakuragi Hirochika , Tokumaru Katsumi 
Published: August 2006

Abstract
Intramolecular quenching of the excited singlet state of a phenanthrene moiety was more efficient in (E)-2-(p-methoxyphenyl)-2-butenyl 9-phenanthrenecarboxylate (E-ABP) than in its Z isomer (Z-ABP) in benzene. The quenching is proposed to proceed in a through-space fashion on the basis of efficiencies of isomerization and photophysical processes as well as molecular orbital calculations.
Characteristic Response of Electrochemical Nonlinearity to Taste Compounds with a Gold Electrode Modified with 4-Aminobenzenethiol
Authors: Mohri Nobuyuki , Katsuya Yoshio , Nakata Satoshi , Yoshikawa Ken-ichi 
Published: August 2006

Abstract
The nonlinear electrochemical responses for various taste compounds were measured using a gold electrode modified by 4-aminobenzenethiol. The results were analyzed quantitatively based on a data-processing method proposed by the authors. The nonlinearity of the response was found to be enhanced by the modification, showing a marked dependence on the categories of taste compounds as well as on their concentrations. Our new concept concerning chemical sensing has been found to be promising as a powerful analytical tool when a suitable modification of the electrode surface is performed.
The Mechanism of Fries Rearrangement and Acylation Reaction in Polyphosphoric Acid
Authors: Sharghi Hashem , Eshghi Hossien 
Published: August 2006

Abstract
Acylation reaction of m-cresol with 2-chlorobenzoic acid in PPA occurred through a prior esterification, followed by a Fries rearrangement of ester (3) to give benzophenones 4—7.
Ester 3 undergoes the Fries rearrangement in PPA, giving benzophenones 4—7 in about the same yield as can be obtained by direct acylation reaction of m-cresol with 2-chlorobenzoic acid. The benzophenone 5 is not stable in PPA and decomposed to benzophenone (4). The formation of benzophenones 4—7, from Fries rearrangement of the ester 3 was interpreted by an intermolecular mechanism.