bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal Structure of Dimethyltin Molybdenum Tetraoxide, (CH3)2SnMoO4
Authors: Sasaki Yukiyoshi , Imoto Hideo , Nagano Osamu 
Published: July 2006

Abstract
Single-crystal X-ray analysis has shown that the title compound is tetragonal, P42/mbc, with a=13.705(2), c=7.271(1) Å. The structure is made of octahedra of trans-Sn(CH3)2O4 and tetrahedra of MoO4. These polyhedra share apices to form a three-dimensional structure.
Structural and Stereochemical Study of Galantinic Acid, a New Amino Acid from Peptide Antibiotic Galantin I
Authors: Wakamiya Tateaki , Ando Toshihiko , Teshima Tadashi , Shiba Tetsuo 
Published: July 2006

Abstract
A new amino acid, galantinic acid, was found as one of the constituent amino acids in a peptide antibiotic galantin I. The structure of galantinic acid was determined to be (2S,4S,5S)-5-amino-2-carboxymethyl-4-hydroxytetrahydropyran on the basis of NMR and CD studies.
Reactions of Arenesulfonyl Chlorides with cis- or trans-β-(Methylstyrene Catalyzed by Ruthenium(II) Complex
Authors: Kamigata Nobumasa , Narushima Tomoo , Sawada Hideo , Kobayashi Michio 
Published: July 2006

Abstract
The reactions of arenesulfonyl chlorides with cis- or trans-β-methylstyrene catalyzed by dichlorotris(triphenylphosphine)ruthenium(II) in the presence of triethylamine proceeded smoothly to give only (E)-2-arylsulfonyl-1-phenylpropene. The recovered cis-β-methylstyrene was isomerized to trans form, while trans-β-methylstyrene did not isomerize to the cis one.
Cyclosadol, Isocyclosadol, and Other Related Triterpene Alcohols Obtained from 24-Methylenecycloartanol by Acid-catalyzed Isomerization
Authors: Shimizu Naoto , Itoh Toshihiro , Ichinohe Yoshiyuki , Matsumoto Taro 
Published: July 2006

Abstract
The acid-catalyzed isomerization of 24-methylenecycloartanol with sulfuric acid afforded cyclosadol (23E-Δ23), isocyclosadol (23Z-Δ23), and other isomers, including lanostane- and cucurbitane-type isomers with (23E)- and (23Z)-Δ23- and Δ24-unsaturated side chains. The phytochemical significance of the isomers is discussed.
Asymmetric Synthesis of Alanine by Catalytic Hydrogenation of Chiral Nα-Acetyldehydroalaninamides
Authors: Harada Kaoru , Takasaki Michiaki 
Published: July 2006

Abstract
Asymmetric hydrogenation of chiral Nα-acetyldehydroalaninamides was studied. The asymmetric yield of the resulting alanine was in the range 0–24%. The effects of reaction temperature, solvent polarity and asymmetric moieties on the asymmetric yields were examined.
Prenylation of Aromatic Amines and Nitrogen-containing Aromatic Heterocycles by Prenyl Diisopropyl Phosphate
Authors: Araki Shuki , Manabe Shin-ichi , Butsugan Yasuo 
Published: July 2006

Abstract
Lewis-acid catalyzed prenylation of aromatic amines with prenyl diisopropyl phosphate gave N-prenylated amines, whereas nitrogen-containing aromatic heretocycles gave nucleus prenylated products.
Oxidation of Alcohols via Alkoxymagnesium Halides by an NAD+ Model Compound
Authors: Shinkai Seiji , Era Hiroyuki , Tsuno Takaharu , Manabe Osamu 
Published: July 2006

Abstract
Alkoxymagnesium bromides prepared from phenylmagnesium bromide and alcohols are capable of reducing an NAD+ model compound to the 1,4-dihydronicotinamide in good yields. The carbonyl products were detected in quantitative yields from diphenylmethanol and 1-phenylethanol but in low yields from benzyl alcohol and aliphatic alcohols. This is a new route to 1,4-dihydronicotinamides with alcohols although it remains uncertainty whether or not the route has relevance as a model process for NAD+ oxidaiton of alcohols.
Resistance to Alkali of the Nascent Fibril Produced by Acetobacter xylinum
Authors: Kai Akira , Koseki Tomoki 
Published: July 2006

Abstract
The resistance of the nascent fibril produced by Acetobacter xylinum to alkali is lower than that of the crystalline cellulose I and higher than that of the amorphous cellulose. In the nascent fibril the cellulose chains are thougth to be in the form of cellulose sheets corresponding to the (1\bar10) plane of cellulose I.
Kinetics and Mechanism of Oxidation of Pyridoxine by Sodium N-Chlorobenzenesulfonamidate
Authors: Jayaram Beby , Mayanna Sarabaghatta Mayanna 
Published: July 2006

Abstract
Oxidation of pyridoxine (PRX) by chloramine-B (CAB) in HCl medium at 313 K shows first order dependence each on oxidant, substrate and Cl− ion concentrations, but is independent of [H+]. A first-order retardation of rate is observed by the addition of reaction product, benzenesulfonamide. Suitable mechanism is proposed.
Optically Active and Racemic Glycerides. I. The Thermodynamic and Structural Relationship between Optically Active and the Corresponding Racemic α-Monostearins in Their Crystalline, Molten, and Dissolved States
Authors: Iwahashi Makio , Watanabe Yasutoshi , Watanabe Toshihiko , Muramatsu Mitsuo 
Published: July 2006

Abstract
The thermodynamic and spectrographic properties, such as the melting temperature, the latent heat of fusion, the solubility, the heat of solution, and the infrared and NMR spectra, were studied for the stable β-forms of the optically active (S)- and the corresponding racemic (RS)-α-monostearin crystals. The phase diagram for the binary mixture and the IR spectra of (S)- and (RS)-crystals indicate that the (RS)- form is a racemic molecular compound consisting of (R)- and (S)-α-monostearin molecules. The latent heats of fusion for the (S)- and (RS)-α-monostearin crystals were 82.4 kJ mol−1 and 75.4 kJ mol−1 respectively. The heats of solution in benzene for the (S)- and the (RS)-crystals were 86.3 and 99.9 kJ mol−1 respectively. The difference in the heat of solution between the (S)- and the (RS)-crystals, Δ(ΔHs), was 13.6 kJ mol−1, which may be attributable to the difference in the extent of hydrogen bonding. These results suggest that (R)- and (S)-molecules in the (RS)-form strongly interact to form a racemic pair not only in the crystalline state, but also in the molten state. Such a racemic pair dissociates into the free molecules when it is dissolved in a nonpolar solvent. The conclusion is supported by the IR and NMR spectra for both the glycerides in dissolved states.
Catalytic Activities of 12-Molybdophosphoric Acid and Its Salts Supported on Silicon Dioxide for the Reduction of Nitrogen Monoxide
Authors: Mochida Isao , Nakashima Toshihiro , Fujitsu Hiroshi 
Published: July 2006

Abstract
12-Molybdophosphoric acid and its metal salts, supported on SiO2 (H3PA and MPA/SiO2), were found to exhibit significant activities for the catalytic reduction of nitrogen monoxide with hydrogen or ammonia, the latter reductant being more reactive. The activity orders of the catalysts were as follows, depending on the reductant: Cu2+&gt;Ag+&gt;Ni2+&gt;Cs+\simeq Co2+\simeq H+ (hydrogen), Cu2+&gt;Co2+&gt;H+&gt;Ag+&gt;Ni2+&gt;Cs+ (ammonia). It is of value to mention also that H3PA/SiO2 exhibited ten times many activity when ammonia was applied. The extent of the cation exchange (X) of CuXH3−2XPA/SiO2 influenced the catalytic activity differently, depending again on the reductant, although the maximum activity was obtained with both reductants when X was 1.1. Nitrogen monoxide was decomposed by a stoichiometric reaction with the reduced site on Cu1.1H0.8PA/SiO2, especially when the catalyst was reduced with hydrogen, although no oxygen was detected in the product, the initial rate being comparable to that of the reduction with hydrogen. The following rate-equations were obtained with the respective reductants on Cu1.1H0.8PA/SiO2 at 300 °C over the partial pressure range of NO (3.0–10.1 kPa) and reductants (3.0–35.5 kPa): V=kH2PNO0.8PH20.04, V=kNH3PNO0.6PNH30.04–−0.7. The wide range in the magnitude of powers with respect to the ammonia partial pressure in the latter equation implies the strong adsorption of ammonia on the catalyst. These results suggest that the redox and Langmuir mechanisms are plausible for the reactions with hydrogen and ammonia respectively. An ESR study of the copper and molybdenum ions of the catalyst supports the above mechanisms.
An Optical-optical Double Resonance Excitation of Bromine to a New D(0u+) Ion-pair State
Authors: Ishiwata Takashi , Tokunaga Atsuto , Shinzawa Tsutomu , Tanaka Ikuzo 
Published: July 2006

Abstract
An optical-optical double resonance (OODR) technique utilizing a sequential three-photon absorption has been applied to study the electronic structure of Br2. Two pulsed dye lasers were used to excite the molecules to appropriate rovibronic levels of the B3Π(0u+) state and subsequently into an ion-pair state by simultaneous two-photon transition. The OODR excitation spectra showed a number of transitions consisting of closely-spaced O, Q, and S branches which combine the B3Π(0u+) state with a new ion-pair state designated D(0u+). The following spectroscopic constants of the D(0u+) state were determined for the 79Br2 isotope species: Te=49925.4(6), ωe=135.7(3), ωexe=0.27(3), Be=0.04190(14), and αe=5.9(23)×10−5 cm−1.
The Circular Dichroism Spectra of cis-[Co(CN)2(CO3)2]3−, cis-[Co(NO2)2(CO3)2]3−, and Related Bis(dicarboxylato) Complexes
Authors: Fujinami Shuhei , Shimoda Akihide , Furukawa Toshihito , Shibata Muraji 
Published: July 2006

Abstract
Five kinds of cis-[Co(CN)2(OO2)]3− and cis-[Co(NO2)2OO)2]3− complexes (OO=CO32−, ox2−, mal2−) have been optically resolved. As to the dicarbonato complexes, one enantiomer has been obtained in a yield far exceeding 50% because of the rapid racemization. When the carbonato ligand is replaced with an oxalato or malonato ligand, the complex becomes inert for racemization and a new Cotton peak with an opposite sign appears at the lower frequency in the first-absorption-band region. The CD spectral change is different from the change observed in cis-[Co(a)2(OO)2]− complexes (a=NH3, py, en/2), suggesting the intimate participation of the unidentate ligands in determining the signs of the Cotton peaks.
Alkali-free Magnesium Phosphate Glasses as Nitrate-ion-selective Materials for Solid-state Electrochemical Sensors
Authors: Nomura Tsuyoshi , Nakagawa Genkichi 
Published: July 2006

Abstract
Ion-selective electrochemical sensors which respond to nitrate-ion activities have been developed. The sensor material consists of alkali-free magnesium phosphate glasses containing CuO, Al2O3, and SiO2. The response characteristics have been observed strongly on the glass composition. Studies of the selectivity coefficient and the electrode function of nitrate-ion activities have shown that the most suitable glass composition is 10CuO : 55P2O5 : 15MgO : 10Al2O3 : 10SiO2. The potential response is linear over the nitrate-ion activities of (10−1–10−5) mol/dm3, and it has a sub-Nernstian response of about 54 mV/decade change at 20 °C. The order of the selectivity is NO3−&gt;ClO4−&gt;I−&gt;NO2−&gt;Cl−&gt;SO32−&gt;&gt;SO42−. Therefore, its use to determine the nitrate-ion activities in a solution containing perchlorate ions is suggested. The physical and chemical properties, such as the glass transition temperature, the softening temperature, the thermal expansion, the membrane resistance, and the chemical durability, were measured and compared with those of other glasses.
Pyrolytic Sulfurization Gas Chromatography. XVI. Pyrolytic Sulfurization Reaction at Atmospheric Pressure and Its Application to the Identification of Carbon, Hydrogen, Oxygen, and Nitrogen in Organic Components
Authors: Hara Tadashi , Okui Fujio 
Published: July 2006

Abstract
A new method by which the component elements: C, H, O, and N, in an organic compound can be simply, rapidly, and economically identified was established on the basis of the reaction of an organic compound with sulfur at atmospheric pressure. The apparatus for this method consists of two gas chromatographs and an original reactor for reacting an organic compound with sulfur vapor. One component separated from a given mixture by the use of one gas chromatograph was made to react with sulfur vapor in the original reactor and then the reaction products were analyzed by the use of the other gas chromatograph. The reaction products were restricted to seven kinds of compounds irrespective of the chemical structure of the target component. According to this method, the component elements: C, H, O, and N, in an organic compound could be easily identified by the reaction products within 20 min with a detection limit of a few pmol.
Organic Photochemical Reactions. XXX. Photoreactions of N,N-Dimethylpyruvamide in Methanol and Ethanol
Authors: Shima Kensuke , Tanabe Kimiko , Furukawa Shinpei , Saito Jouji , Shirahashi Kazuhiro 
Published: July 2006

Abstract
The photoreactions of N,N-dimethylpyruvamide (DMPA) in methanol and ethanol were investigated. Irradiation of DMPA in methanol gave three products (3,5-dimethyl-4-oxazolidinone, 2-hydroxy-N-methyl-N-(methoxymethyl)propanamide, and 2,3-dihydroxy-2,3-dimethyl-N,N,N′-trimethyl-N′-(methoxymethyl)-butanediamide) in good yields. The product distribution was dependent on the concentration of DMPA and methanol. Similarly, irradiation of DMPA in ethanol gave three products (3,5-dimethyl-4-oxazolidinone, 2-hydroxy-N-methyl-N-(ethoxymethyl)propanamide, and 2,3-dihydroxy-2,3-dimethyl-N,N,N′-trimethyl-N′-(ethoxymethyl)butanediamide). The mechanism for the formation of these products is discussed.
The Enantioface-differentiating Hydrogenation of the C=O Double Bond with Asymmetrically Modified Raney Nickel. XXXVIII. The Hydrogenation of Methyl Ketones to Optically Active Secondary Alcohols
Authors: Osawa Tsutomu , Harada Tadao 
Published: July 2006

Abstract
The enantioface-differentiating (asymmetric) hydrogenation of various methyl ketones (R–COCH3) was carried out over the Raney nickel catalyst modified with (R,R)-tartaric acid and sodium bromide. The presence of an appreciable amount of carboxylic acid in the reaction system was indispensable for a high optical yield. The highest optical yield (74%) was obtained in the hydrogenation of 3,3-dimethyl-2-butanone in the presence of pivalic acid.
Yields of Electron Transfer Reactions in the Quenching of the Phosphorescent States (2E) of Tris(2,2′-bipyridine)chromium(III) and Tris(4,7-diphenyl-1,10-phenanthroline)chromium(III) Compounds
Authors: Ohno Takeshi , Kato Shunji 
Published: July 2006

Abstract
Molar absorption coefficients of the phosphorescent states (2E) of [Cr(2,2′-bipyridine)3]3+ and [Cr(4,7-diphenyl-1,10-phenanthroline)3]3+ were determined. The 2E state of [Cr(2,2′-bipyridine)3]3+ was reduced to [Cr(2,2′-bipyridine)3]2+ with the yield of less than 0.2 in the quenching by iron(II) compounds. The reduction yields of [Cr(2,2′-bipyridine)3]3+ and [Cr(4,7-diphenyl-1,10-phenanthroline)3]3+ in the quenching of 2E by aromatic amines increase with the Gibbs energy change (−ΔG) in the reverse electron-transfer process. The weak dependence of the yields on ΔG can not be interpreted in terms of adiabatic reverse electron transfer in the geminate pair, which is formed in the quenching process. The electron transfer from the chromium(II) compounds of triplet spin-multiplicity to the amine radical of doublet spin-multiplicity suffers from spin-restriction.
Determination of a Small Amount of Biological Constituent by Use of Chemiluminescence. III. The Flow-injection Analysis of Protein by Direct Injection
Authors: Hara Tadashi , Toriyama Motohiro , Tsukagoshi Kazuhiko 
Published: July 2006

Abstract
A flow-injection analysis method of protein by direct injection has been established by use of the luminol-hydrogen peroxide luminescence system. The determination of protein is based on the measurement of the decreasing catalytic activity of copper(II) for the chemiluminescent reaction between luminol and hydrogen peroxide. The present flow-injection analysis in which a protein solution is directly injected is quite different from the previous one in which a protein solution is injected after having been previously allowed to react with copper(II) outside the flow-through system. The optimum conditions for the determination of protein were determined with regard to reagent concentration, flow rate, reaction time, and reaction temperature. The present method is simple, rapid, and applicable to the determination of 2×10−4–1×10−1 g dm−3 of protein with 40 ng of detection limit at a rate of about 30 samples per hour. The present method was also applied to the determination of the ratio of albumin to globulin in a sample. The present flow-injection system is expected to be a sensitive detector for the determination of small amounts of protein.
A Kinetic Study on Oxidation of a Pair of Associating Thiols Having Substituted Phenyl Groups with Oxygen
Authors: Endo Tadashi , Hashimoto Masao , Orii Toyohiko , Ito Masato M 
Published: July 2006

Abstract
The rates of oxidation of 1:1 mixtures of associating thiols, each having the binding site (Remark: Graphics omitted.) and the recognition site [p-(CH3)2NC6H4 or R], with O2 were measured in 80% (v/v) acetonitrile-20% water in the range of 20 to 50 °C. Oxidation of the thiol having the p-(CH3)2NC6H4 group proceeds about 100 times faster than that of the thiols with R. It has been found that oxidation of 1:1 mixtures of the thiols is first-order with respect to thiols and 0.7 th-order with respect to triethylamine by means of the method of initial rates. The k1.7 values for R=C6H5, p-CH3C6H4, and p-C2H5C6H4 were similar to one another; this makes a sharp contrast with our previous work that the selectivity (the logarithmeric ratio of the yield of the unsymmetrical disulfide to twice that of the symmetrical disulfide) changes greatly with the structures of R and temperature. It is concluded that the product ratio does not depend upon the k1.7. The large negative activation entropies (−51 to −45 cal K−1 mol−1) suggest that the oxidation would proceed through a highly ordered transition state.
Formation Process of Niobium Nitride by the Reaction of Niobium Pentachloride with Ammonia in the Vapor Phase and Properties of the Niobium Nitride Formed
Authors: Yajima Akimasa , Arai Takashi , Matsuzaki Ryoko , Saeki Yuzo 
Published: July 2006

Abstract
The reaction products of gaseous NbCl5 with ammonia were NbCl5·5NH3 at 200 °C, NbCl5·5NH3, Nb4N5, and NH4Cl at 250–500 °C, Nb4N5 and NH4Cl at 550–950 °C, δ-NbN and NH4Cl at 1000 °C, δ-NbN, Nb2N, NH4Cl, and HCl at 1100 °C, and δ-NbN, Nb2N, Nb4N3, δ′-NbN, ε-NbN, NH4Cl, and HCl at 1200–1300 °C. In the vapor-phase reaction of gaseous NbCl5 with ammonia, the reaction of gaseous NbCl5 with ammonia to form NbCl5·5NH3 occurs first. Above ca. 235 °C, the NbCl5·5NH3 reacts with ammonia to form Nb4N5. Above ca. 1000 °C, the Nb4N5 decomposes to δ-NbN. Above about 1100 °C, in addition to these reactions, the nitriding of niobium, formed by the reduction of gaseous NbCl5 with the hydrogen resulting from the thermal dissociation of ammonia, also occurs to form Nb2N at 1100 °C and Nb2N, Nb4N3, δ′-NbN, and ε-NbN at 1200–1300 °C. When the Nb4N5, formed by the vapor-phase reaction, is heated in an argon atmosphere, it changes to δ-NbN at ca. 1000 °C, to δ-NbN and ε-NbN at 1100–1200 °C, and then to Nb4N3 and δ-NbN at 1300 °C. The niobium nitrides formed above 1200 °C are uniform, ultrafine powders with particle diameters of the order of 1/100 μm.
Kinetic Study on Hydrolysis of Silicon Phosphate in Aqueous Alkaline Solutions
Authors: Saeki Tomoji , Narita Eiichi , Naito Hiroyuki 
Published: July 2006

Abstract
Kinetic study of the hydrolysis of silicon phosphate, Si3(PO4)4 (hexagonal), was carried out in borax buffer solutions (pH 5–12, temperature 20–50 °C) to investigate how it acts as a hardener for alkali silicate adhesive. The silicon phosphate was found to be hydrolyzed with a resulting release of orthophosphate ion, soluble silicate ions, and colloidal silica under mild conditions; the decomposition rate increased with decreasing the particle size of the phosphate and with increasing the pH and temperature of the buffer solution. From the analysis of the decomposition rate on the basis of the shrinking core model, it was found that the decomposition rate could be adequately expressed by the rate equation based on the mixed control of diffusion through a residual layer and surface chemical reaction. This indicates that a part of the colloidal silica which resulted from the hydrolysis remains on the surface of the silicon phosphate particle and then partially limits the overall rate of the hydrolysis. The dependence of both rate-determining steps for the decomposition rate was quantitatively indicated according to the reaction conditions.
Hydrophilicity and Complexing Ability of Alkyl Lariat Ethers
Authors: Ikeda Isao , Emura Hiroshi , Okahara Mitsuo 
Published: July 2006

Abstract
A series of long chain alkyl lariat ethers were synthesized and their aqueous properties in the absence and presence of alkali metal cations were investigated by measuring their cloud points and complex stability constants. In spite of the presence of ether oxygen(s) in the side chain, complexing abilities toward sodium and potassium cations did not significantly differ from those of the corresponding alkyl crown ethers. As the number of ether oxygens in the side chain of lariat ethers was increased, the water solubilities were much improved and showed high cloud points. However, the degree of salting-in effect decreased and the increment of cloud point caused by addition of salts decreased, probably due to the increase of acyclicity of the polyether molecule.
Polarized Absorption Spectra of Aromatic Radicals in Stretched Polymer Film. V. The Benzophenone Radicals
Authors: Minegishi Tsuneyuki , Hiratsuka Hiroshi , Tanizaki Yoshie , Mori Yuji 
Published: July 2006

Abstract
Benzophenone radical anions and ketyl radicals have been prepared in poly(vinyl alcohol) [PVA] films by means of γ-ray irradiation at 77 K. The polarized absorption spectra have been measured and used to determine the resolved spectra of these radicals. The spectrum of radical anions in the PVA film is very similar to that of ketyl radicals and can also be well explained by the calculated results for the hydrogen-bonding model of radical anions. The intense near-UV and visible absorption bands of radical anions in the PVA film are both correlated with those of ketyl radicals.
An Account of the Site- and Regio-selectivity in the Reaction of Nitrile Oxides with Substituted p-Benzoquinones by Frontier Molecular Orbital Theory
Authors: Hayakawa Tohru , Araki Koji , Shiraishi Shinsaku 
Published: July 2006

Abstract
The 1,3-dipolar cycloaddition reactions of nitrile oxides with substituted p-benzoquinones are discussed in terms of Frontier Molecular Orbital (FMO) theory. The calculation is carried out by ab initio Self Consistent Field (SCF) method with STO-3G basis set. The site- and regio-selectivities in the reactions are correlated with two types of FMO interactions. Some predictions have been confirmed by experimental results.