bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microviscosity and Micellar Phase Diagrams Determined with Fluorescence Probes
Authors: Miyagishi Shigeyoshi , Kurimoto Hirotaka , Asakawa Tsuyoshi 
Published: July 2006

Abstract
The dependence of microviscosity on salt and surfactant concentrations was determined in micellar solutions of alkyltrimethylammonium bromides by using two fluorescent probes, auramine and 1,3-dipyrenylpropane (P3P). The microviscosity increased with the growth of the micelles, it changed at the sphere to rodlike micelles transition point, and it became constant above the overlap threshold point of rod micelles, that is, the overlapping of micelles did not influence the microviscosity. The transition points of the micellar solutions (the critical micelle concentrations, the sphere-rod transition point, and the micelle overlapping point) determined by the present method were in good agreement with those in the literature. Phase diagrams of the micellar solutions were determined from the above data.
Internal Rotation of the Methyl Groups in the t-Butyl Radical as Studied by ESR
Authors: Kubota Souichi , Matsushita Michio , Shida Tadamasa , Abu-Raqabah Atieh , Symons Martyn C R , Wyatt Jane L 
Published: July 2006

Abstract
The ESR spectrum of the t-butyl radical in a rigid matrix is observed at temperatures between 6.6 and 70 K. At temperatures below about 50 K equally spaced nineteen lines are observed which is associated with the tunneling rotation of the three methyl groups. By the analysis of the spectral pattern at a low temperature of 6.6 K the pairwise interaction potential of the internal rotation, if any, is deduced to be proportional to cos θi cos θj where θi and θj are the internal rotation angles of two methyl groups. By the simulation of the spectral change with temperature the thermal activation energy for the internal rotation is estimated to be 6 ± 2 kJ mol−1.
The Aggregated Higher-Structure of 1,3 : 2,4-Di-O-benzylidene-d-sorbitol in Organic Gels
Authors: Yamasaki Seiji , Ohashi Yukihiro , Tsutsumi Hisao , Tsujii Kaoru 
Published: July 2006

Abstract
1,3 : 2,4-Di-O-benzylidene-d-sorbitol (d-DBS) can cause gelation of organic solvents of a wide range of polarity into a gel state. The aggregated structures of d-DBS/organic solvent systems were studied, mainly by using IR, UV, and circular dichroism (CD) spectroscopy. In the case of the racemate Dl-DBS, no gel state was formed. In IR spectra of d-DBS and Dl-DBS in the solid state, the intensities of νOH and νCO absorption in d-DBS were found to be larger than those in Dl-DBS. It is assumed that the hydrogen bonding formed between an acetal oxygen and a hydroxyl group in the aggregation of d-DBS. From the changes in the IR spectra from solution into a gel state, we can conclude that the chirality and the hydrogen bonding of DBS molecules are essential for the formation of the gel. Comparing the gel-forming ability of d-DBS with its derivatives, 5- or 6-hydroxyl-group-blocked compounds by methyl group, the 6-hydroxyl group seems to be important in the formation of d-DBS aggregates. The results of UV spectra suggest that the benzene rings are ordered in a side by side arrangement. The molar ellipticities in CD spectra increased about 500 times during the change from the solution to the gel state. From these results, it is concluded that d-DBS forms a helical structure of thin fibrous crystals in the gel state.
Synthesis of Electroactive Protein Hybrid, Fec-BSA-Dig, and Its Application to a Novel Homogeneous Electrochemical Immunoassay
Authors: Suzawa Toshiyuki , Ikariyama Yoshihito , Aizawa Masuo 
Published: July 2006

Abstract
A novel homogeneous electrochemical immunoassay using ferrocene- (Fec-), digoxin- (Dig-) doubleconjugated protein, has been developed. The system is based on the principle that electrochemical activity of the conjugate is suppressed in the presence of an antibody, and restored in the presence of free digoxin. Hence, a new homogeneous immunoassay can be carried out when the electroactivity of the conjugate is determined. Here, we synthesize the conjugate by controlling the numbers of ferrocene and digoxin on individual carrier proteins simultaneously. Bovine serum albumin (BSA) is selected as a carrier protein to which the electrochemical labels and the several hapten molecule are bound by Schiff’s base formation. Since the conjugate synthesized here behaves as a multivalent antigen, and is capable of binding to antidigoxin antibody, therefore the antigen having electrochemical activity loses its activity depending on antibody concentration. When the conjugate, in which 39 molecules of ferrocene and 8 molecules of digoxin are bound, is used for the inhibition experiment of electrochemical reaction before and after the immunoreaction, peak height currents, responsible for the redox reactions of the bound ferrocene, decreased depending on the added antibody in a dose-dependent fashion. This system is feasible as a homogeneous electrochemical immunoassay, since the method may provide a simple and a rapid approach toward a homogeneous assay of bioactive substances.
C,N-Chelated (2-Pyridylmethyl)rhodium(III) Complexes and a Novel Dinuclear Rhodium(III) Complex Containing a 2,6-Dimethylpyridine-α,α′-diyl Group as an η2(C,N) : η3(C,C′,N)-Bridging Ligand
Authors: Shinkawa Nobuyuki , Sato Aya , Shinya Junko , Nakamura Yukio , Okeya Seichi 
Published: July 2006

Abstract
Oxidative-addition reactions of excess 2-(chloromethyl) and 2,6-bis(chloromethyl)pyridines with [RhCl(PPh3)3] in toluene at room temperature afforded (2-pyridylmethyl)- and {2-(6-chloromethyl)pyridylmethyl}rhodium(III) complexes, cis(PP)-[RhCl2{C5H3(6-R)N-2-CH2}(PPh3)2] (R = H, 1-cis; R = CH2Cl, 2-cis), respectively, which isomerized to the corresponding trans(PP) complexes at elevated temperature. In refluxing toluene, the reactions thus resulted in the trans(PP) complexes (R = H, 1-trans; R = CH2Cl, 2-trans) exclusively. A novel dinuclear rhodium(III) complex [Rh2Cl4{C5H3N-2,6-(CH2)2}(PPh3)2], in which the 2,6-dimethylpyridine-α,α′-diyl ligand is C,N-chelated to one rhodium atom and bound to the second one in an η3-pseudo-1-azaallylic fashion, was obtained by reactions of 2,6-bis(chloromethyl)pyridine with [RhCl(PPh3)3] (1 : 2 in mole) and of the 2-cis with [RhCl(PPh3)3] (1 : 1 in mole), both in refluxing toluene. These were characterized by 1H, 13C, and 31P NMR spectroscopy and mass spectrometry as well as an elemental analysis and a molecular-weight determination.
Studies of the Hydrous Titanium Oxide Ion Exchanger. IV. Rate of the Isotopic Exchange of Sodium Ions between the Exchanger in the Na+ Form and Aqueous Solution
Authors: Inoue Yasushi , Yamazaki Hiromichi , Kasuga Fuminori 
Published: July 2006

Abstract
The isotopic exchange rate of Na+ between hydrous titanium(IV) oxides, precipitated at pH 6 and 13, in the Na+ form and aqueous solution of sodium salt was determined radiochemically. The rate in the exchanger precipitated at pH 6 is controlled by the diffusion of Na+ in the exchanger particles (particle diffusion). The diffusion coefficient and its activation energy are 1.9 × 10−11 m2 s−1 (pH 12, 5.0 °C) and 29 kJ mol−1 (pH 12), respectively. The rate in the exchanger precipitated at pH 13 is also controlled by the particle diffusion. The rate is much slower than that in the other; this can be explained by assuming the existence of two kinds of independently diffusing ions (fast and slow species) in the exchanger. The diffusion coefficients are of the order of 10−12 and 10−13 m2 s−1 for the fast and the slow species, respectively. Their activation energies are 48—60 kJ mol−1 at pH 12. The marked difference in kinetics between two exchanges was interpreted in terms of the difference in the acid-base property and in the microstructure of the matrix.
Effects of ortho-Methyl Substituents on the Rate of Dissociation of Imidazole Ligands in Tetraarylporphyrinatocobalt(III) Complexes
Authors: Nakamura Mikio 
Published: July 2006

Abstract
Dissociation rates of the imidazoles in [Co(tpp)(L)2]+ and [Co(tmp)(L)2]+, where L is an unhindered imidazole such as 1-methylimidazole or a hindered imidazole such as 2-alkylimidazole, have been determined in chloroform-d solution by the 1H NMR saturation transfer method. The rate constants in the tmp complexes were smaller than those of the corresponding tpp complexes in every imidazole ligand examined. The largest difference between these two systems was observed in bis(1,2-dimethylimidazole) complexes and the ratio of the rate constants, k(tpp)/k(tmp), reached as much as 2500 at 90 °C. While the rate constants greatly increased in the tpp system on going from the unhindered imidazole to the hindered one, the increase was rather small in the tmp system. These results were interpreted in tems of the deformation of the porphyrinatocobalt core: Since the two hidered ligands in the tmp complexes are fixed perpendicularly in the cavities created by the deformed porphyrin ring, the distance between the 2-alkyl and the deformed porphyrinatocobalt core would increase, which results in weakening the steric repulsion and slowing down the dissociation rate. The attractive interaction between the ortho-methyls and the imidazole π system would also contribute to the stability of the tmp complexes.
Formation of 2,6-Naphthalenedicarboxylic Acid by the Co–Mn–Br-Catalyzed Autoxidation of 2,6-Diethylnaphthalene in Acetic Acid
Authors: Kamiya Yoshio , Hama Takashi , Kijima Ichiro 
Published: July 2006

Abstract
In order to elucidate the reaction mechanism and the optimum reaction conditions for the formation of 2,6-naphthalenedicarboxylic acid (NDCA), the Co(OAc)2–Mn(OAc)2–NaBr-catalyzed oxidation of 2,6-diethylnaphthalene by molecular oxygen was carried out in acetic acid. The oxidation of the ethyl groups to carboxyl groups proceeded mainly via acetyl groups and partly via 1-hydroxyethyl and 1-acetoxyethyl groups. A synergistic catalytic effect due to Co and Mn acetates was observed not only on the rate of oxidation but also on the selective formation of NDCA. The rate of oxidation was strongly retarded at higher concentrations of the substrate, showing that the naphthalene nucleus terminates the chain reaction step of the oxidation. A high concentration of metal catalyst resulted in an increase of acetoxyethylnaphthoic acid. At the optimum reaction conditions, a nearly 90% yield of NDCA was obtained along with small amounts of substituted naphthoic and trimellitic acids. The differences in the yield of NDCA from 2,6-dimethyl, 2,6-diethyl, and 2,6-diisopropylnaphthalenes were compared under similar reaction conditions and are discussed.
Preparation of 2-Hydroxymethylated Aldose by the Stereospecific Rearrangement of Ketose
Authors: Yanagihara Ryoji , Egashira Jun , Yoshikawa Sadao , Osanai Shuichi 
Published: July 2006

Abstract
A simple one-stage reaction system which yields 2-C hydroxymethylated aldopentose has been investigated. Four different 2-C branched aldopentoses (2-C hydroxymethylated d-arabinose, d-ribose (Hamamelose), l-lyxose, and d-xylose) were prepared from the corresponding ketoses (d-psicose, d-fructose, l-sorbose, and d-tagatose, respectively). These branched sugars were synthesized by a similar mechanism to the 2-C epimerization of aldose using a nickel complex. It was confirmed that the isomerization of ketose to the side-branched sugar proceeded in the ternary nickel complex through a sequence of stereospecific rearrangements in the sugar. The yields were dependent upon the structure of the substrate ketose and the nickel-ethylenediamine complex. N,N′-Dialkylated cyclohexanediamines were the most suitable ligands for preparing the 2-C hydroxymethylated branched chain sugar.
Attempts at Direct Detection of Reactive Species in Selective Excitation of the Contact Charge Transfer Pairs of Hexamethylbenzene and Oxygen
Authors: Komatsu Toshiki , Tsuchiya Masahiro , Furusawa Gen-ichi , Kuriyama Yasunao , Sakuragi Hirochika , Nakanishi Fusae , Tokumaru Katsumi 
Published: July 2006

Abstract
Pulsed laser excitation of contact charge transfer pairs of hexamethylbenzene (HMB) and oxygen in methanol-acetonitrile gave no evidence for intermediacy of reactive species such as HMB radical cations and pentamethylbenzyl cations (ArCH2+), though stationary irradiation of the pair in hydroxylic solvents afforded distinct products arising from the cationic species. The mechanism of reactions was discussed in comparison with 9,10-dicyanoanthracene-sensitized oxygenation of HMB.
Reduction of Arylcarbonyl Using Zinc Dust in Acetic Acid
Authors: Rani B Radha , Ubukata Makoto , Osada Hiroyuki 
Published: July 2006

Abstract
Zinc dust in acetic acid has been found to be a versatile and chemoselective reagent for the reduction of various arylcarbonyls to the corresponding alcohols or their acetates in fair yields.
Stereochemical Control in Microbial Reduction. XXV. Additives Controlling Diastereoselectivity in a Microbial Reduction of Ethyl 2-Methyl-3-oxobutanoate
Authors: Kawai Yasushi , Takanobe Kousuke , Ohno Atsuyoshi 
Published: July 2006

Abstract
Stereoselectivity of microbe-catalyzed reduction of ethyl 2-methyl-3-oxobutanoate to optically active 3-hydroxy-2-methylbutanoate can be controlled by the addition of methyl vinyl ketone to the reaction system. The reduction by Geotrichum candidum, Endmyces magnusii, and Mucor javanicus with an appropriate additive affords the corresponding anti-(2S,3S)-hydroxy ester selectively, whereas the reduction by bakers’ yeast and Candidatropicalis with an additive gives the corresponding syn-(2R,3S)-hydroxy ester selectively.
Practical and Safe Sulfonylation of 2-Alkynyl and 2-Alkenyl Alcohols Using the Combined Bases of a Catalytic Amount of Tertiary Amine and Potassium Carbonate
Authors: Tanabe Yoo , Yamamoto Hitomi , Yoshida Yoshihiro , Miyawaki Takashi , Utsumi Naoka 
Published: July 2006

Abstract
Several 2-alkynyl and 2-alkenyl alcohols were effectively sulfonylated with methanesulfonyl chloride or p-toluenesulfonyl chloride using the combined bases of a catalytic amount of tertiary amine and potassium carbonate. The reaction was conducted with reliable safety and while avoiding the disposal of wasted amines. The mesylation of 2-propyn-1-ol proceeded on a large scale (more than 20 kg) without a substantial production of explosive 3-chloro-1-propyne. The choice of the catalysts was important, and sterically unhindered tertiary amines, such as trimethylamine, N,N-dimethylbenzylamine, and triethylamine, were effective. Without these catalysts the reactions were significantly retarded. The reaction was so mild that it could be applied to complex and optically active 4-hydroxy-3-methyl-2-(2-propynyl)-2-cyclopenten-1-one, which is an important alcohol moiety of synthetic pyrethroids.
Thermolysis of Dicyclopentadienylmethyl Alcohols. A Novel Synthesis of Fulvenes
Authors: Kumagai Takashi , Ohno Mayumi , Mitani Kooji , Yamamoto Ken-ichi , Oda Masaji 
Published: July 2006

Abstract
Thermolyses of isomeric mixtures of dicyclopentadienylmethyl alcohols were obtained by reactions of the corresponding isomeric mixture of metallodicyclopentadiene with aldehydes and ketones at 300 °C by a flow method. These thermolyses give by cycloreversion the corresponding isomeric mixtures of cyclopentadienylmethyl alcohols. These mixtures in turn furnish the corresponding fulvenes upon treatment with bases. At higher temperatures, the thermolyses regenerate starting ketones, probably by retro-ene reaction of the cycloreversed alcohols.
Efficient Preparation of Alkoxymethyl Carbonates by Using Potassium Carbonate, Chloromethyl Alkyl Ethers, and Alcohols
Authors: Teranishi Katsunori , Komoda Atsuko , Hisamatsu Makoto , Yamada Tetsuya 
Published: July 2006

Abstract
A synthesis of new “alkoxymethyl carbonate” is presented starting with alcohol. In the presence of potassium carbonate, primary alcohols react with chloromethyl alkyl ethers in N,N-dimethylformamide under mild conditions to give the corresponding alkoxymethyl carbonates in good yields without giving the alkoxymethyl ethers. The yield of alkoxymethyl carbonate is seriously effected by reaction solvent and the present method is not applicable for tertiary alcohol. Methoxymethyl carbonate can be removed readily under mild basic or acidic conditions, and undergoes selective alkoxide interchange of methoxymethoxide group under basic conditions.
Studies on Synthetic Ionophores. X. Transport Behavior of Na+ and K+ with an ω-Hydroxy Carboxylic Acid Containing Octaether Linkages as a Synthetic Analog of Natural Carboxylic Acid Ionophores through an Organic Liquid Membrane
Authors: Yamaguchi Kazuo , Kuboniwa Hitoshi , Nagami Satoru , Bando Toru , Hirao Akira , Nakahama Seiichi , Yamazaki Noboru 
Published: July 2006

Abstract
2-[[2-[2-[2-[2-[2-[2-[2-(2-Hydroxyethoxy)phenoxy]ethoxy]phenoxy]ethoxy]phenoxy]ethoxy]phenoxy]methyl]benzoic acid (1) was employed as a carrier to transport alkali metal ions. The transport selectivity sequence through 1,2-dichloroethane membrane was K+ ≥ Rb+ &gt; Cs+ &gt; Na+ ≥ Li+. The high preference of K+ to Na+ in competitive transport through 1,2-dichloroethane–toluene was consistent with the difference of solubility between the potassium and sodium salts of 1. However, the separate transport rates of K+ and Na+ through 1,2-dichloroethane were comparable. The amount of water incorporated from aqueous to organic layer by the sodium salt was much more than by the potassium salt, and the amounts were dependent on the stirring rates of the two layers. The sodium salt lowered the interfacial tension between the aqueous and organic layers, while the potassium salt did not change it. Emulsion-like aggregates of the sodium salt in the organic layer were observed by dynamic light scattering. The above experiments showed that K+ was transported as the potassium salt of 1, while Na+ was incorporated into the organic layer and transported as an aggregate of the sodium salt containing water.
Stereo- and Chemo-Selectivity in Reduction of α-[Phenyl(or Methyl)seleno]alkyl Aryl Ketones with Metal Hydrides
Authors: Aoki Ikuo , Nishibayashi Yoshiaki , Uemura Sakae 
Published: July 2006

Abstract
Metal hydride reduction of a variety of α-[phenyl(or methyl)seleno]alkyl aryl ketones gives a mixture of threo- and erythro-β-aryl-β-hydroxyalkyl phenyl(or methyl)selenides by carbonyl reduction and 1-aryl-1-alkanol by the substitution of a phenyl(or methyl)seleno group with hydrogen. With all metal hydrides examined the formation of the threo-isomer always predominated. The addition of various metal chlorides in the reduction system did not affect the diastereoselectivity much, in a sharp contrast to the so-far known reduction of various α-heteroatom (N, P, O, S)-substituted ketones.
Stereoselective Reduction of β,δ-Diketo Esters. A Novel Strategy for the Synthesis of Artificial HMG-CoA Reductase Inhibitors
Authors: Hiyama Tamejiro , Reddy Guntoori Bhaskar , Minami Tatsuya , Hanamoto Takeshi 
Published: July 2006

Abstract
Condensation of N-methoxy-N-methyl amides with the dianions of acetoacetates gives in good yields β,δ-diketo esters, which are reduced with Et2BOMe–NaBH4 in tetrahydrofuran–methanol highly selectively to give syn-β,δ-dihydroxy esters in one step. Similarly, the β,δ-diketo esters of the Taber’s chiral alcohol or its enantiomer respectively are reduced to give syn-β,δ-dihydroxy esters of moderate enantiomeric excess. Higher diastereo- and enantioselectivity were achieved by reduction of the β,δ-diketo esters of the Taber’s chiral alcohol or its enantiomer successively with diisobutylalane and with Et2BOMe–NaBH4. The resulting syn-diol esters were hydrolyzed and lactonized to give various types of β-hydroxy-δ-lactones commonly found in artificial HMG-CoA reductase inhibitors.
Polymerization of Sulfur-Containing Aromatic Disubstituted Acetylenes and Polymer Characterization
Authors: Watase Takanori , Tachimori Hiroshi , Masuda Toshio 
Published: July 2006

Abstract
1-Phenylthio-1-alkynes (PhS–C≡C–R; R = Me, n-Bu, n-C6H13, n-C8H17, n-C10H21, and n-C12H25) polymerized in 40—80% yields in toluene at 80 °C in the presence of MoCl5–Ph3SiH (1 : 2) catalyst, but did not polymerize with the corresponding W catalyst. The produced polymers with R = n–C8H17 and longer were soluble in toluene, chloroform, etc., whose weight-average molecular weights (Mw) reached 2 × 104. 1-Alkylthio-2-phenylacetylenes (RS–C≡C–Ph; R = Me, Et, n-Bu) polymerized in 10—20% yields with a WCl6–Ph3SiH (1 : 2) catalyst, while they did not produce any polymer with Mo catalysts. Only the polymer with R = n–Bu was soluble in several organic solvents, whose Mw was ca. 1 × 104. Although 1-phenylthio-2-phenylacetylene (PhS–C≡C–Ph) polymerized with both MoCl5–Ph3SiH and WCl6–Ph3SiH, the produced polymers were insoluble in all solvents. Poly(1-phenylthio-1-dodecyne) and poly(1-butylthio-2-phenylacetylene) were yellow solids with absorption maxima at around 280 m; their weight loss in a thermogravimetric analysis started at around 200 °C.
Enzymatic Ring-Opening Polymerization of Lactones to Polyesters by Lipase Catalyst: Unusually High Reactivity of Macrolides
Authors: Uyama Hiroshi , Takeya Kazuhiro , Kobayashi Shiro 
Published: July 2006

Abstract
Enzymatic ring-opening polymerization of macrolides was carried out by using various lipases as catalysts. The monomers used in this study were 11-undecanolide (12-membered, UDL) and 15-pentadecanolide (16-membered, PDL). Among the enzymes examined, lipases derived from Pseudomonas fluorescens (lipase P) and from Candida cylindracea (lipase B) gave polyUDL with high molecular weight in a high yield. From 1H and 13C NMR analysis, the polymer was found to possess the terminal structure of a carboxylic acid group at one end and a hydroxyl group at the other. The rate of the UDL polymerization using lipase P was larger than that using lipase B, whereas the polymerization of UDL using lipase B produced the polymer of higher molecular weight in comparison with that obtained by using lipase P. Lipases from Pseudomonas sp. and porcine pancreas showed a catalytic activity for the polymerization of UDL. PDL was also polymerized by lipase catalyst to give the corresponding polyester. The enzymatic polymerizations of UDL and PDL have been compared with that of 6-hexanolide (ε-caprolactone, ε-CL). The polymerization of the macrolides using lipase P proceeded much faster than that of ε-CL. This is probably due to the strong recognition of the macrolides by the lipase catalyst.
Catalytic Addition of Aromatic Carbon–Hydrogen Bonds to Olefins with the Aid of Ruthenium Complexes
Authors: Kakiuchi Fumitoshi , Sekine Shinya , Tanaka Yasuo , Kamatani Asayuki , Sonoda Motohiro , Chatani Naoto , Murai Shinji 
Published: July 2006

Abstract
Ruthenium complexes, e.g., Ru(H)2(CO)(PPh3)3, have been found to catalyze the addition of ortho C–H bonds of aromatic ketones to olefins with a high degree of efficiency and selectivity. 2′-Methylacetophenone reacts with various types of terminal olefins to give 1 : 1 coupling products in good to excellent yields. The C–C bond formation takes place exclusively at the terminal carbon atom of olefins except for styrene which affords a mixture of two regioisomers. Acetylnaphthalenes, cyclic aromatic ketones, and heteroaromatic ketones also react with triethoxyvinylsilane to give 1 : 1 addition products in virtually quantitative yields. From 2′-acetonaphthone or 3-acetylthiophene, in which two different reaction sites are available, only one out of four possible regioisomers is obtained. The importance of the coordination of the oxygen atom of the ketone to ruthenium and the intervention of a cyclometallation intermediate are suggested. A deuterium labeling experiment using acetophenone-d5 and triethoxyvinylsilane shows that an H/D exchange between the aromatic and olefinic positions takes place to some extent, even prior to the formation of the product. This implies that the rate-determining step is not the C–H bond cleavage step, but the product forming step.