bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Building Blocks for Heterocyclic Syntheses. Silylated Methyl Isothiocyanates
Authors: Hirao Toshikazu , Yamada Atsushi , Hayashi Ken-ichiro , Ohshiro Yoshiki , Agawa Toshio 
Published: July 2006

Abstract
Trimethylsilylmethyl isothiocyanate, bis(trimethylsilyl)methyl isothiocyanate, and tris(trimethylsilyl)methyl isothiocyanate were prepared. The fluoride-catalyzed reaction of trimethylsilylmethyl isothiocyanate with aldehydes or ketones afforded oxazolidine-2-thione derivatives, which involves the isothiocyanato carbanion as an intermediate. Imidazolidine-2-thiones were similarly prepared from imines. The reaction of bis(trimethylsilyl)methyl isothiocyanate with benzaldehyde in the presence of a catalytic amount of n-Bu4NF gave styryl isothiocyanate and 5-phenyl-4-trimethylsilyloxazolidine-2-thione. On the similar treatment of tris(trimethylsilyl)methyl isothiocyanate, 4-benzyl-5-phenyl-4-oxazoline-2-thione, and α-(trimethylsilyl)styryl isothiocyanate were obtained.
Gas-chromatographic Measurements of Dinitrogen Oxide in Air
Authors: Muramatsu Hisafumi , Hirota Michio , Makino Yukio 
Published: July 2006

Abstract
To obtain an average tropospheric mixing ratio of dinitrogen oxide over Japan, 90 air samples were collected by aircraft at altitudes up to 7 km from Autumn, 1978, to Spring, 1979, and were analysed by the GC-ECD method. The mean volume-mixing ratio of N2O was 0.310 ppm, and the standard deviation was 0.014 ppm. These results show that the tropospheric N2O is well mixed and that its mixing ratio is higher than 0.30 ppm.
The Thermal Decomposition of N,O-Diacyl-N-t-butylhydroxylamines. III. Novel Routes to 2-Substituted 1,2-Benzisothiazol-3-(2H)-ones
Authors: Uchida Yuzuru , Kozuka Seizi 
Published: July 2006

Abstract
The reactions of N-alkyl- and N-aryl-2-(methylsulfinyl)benzamides and N-[2-(methylthio)benzoyl]-N-alkylhydroxylamines with thionyl chloride have been found to give 2-substituted 1,2-benzisothiazol-3(2H)-ones in nearly quantitative yields. The reactions of N-[2-(methylthio)benzoyl]-N-arylhydroxylamines with thionyl chloride gave chlorinated anilides as the major products.
Upon DNP-aromatic Rule. Effect of Introducing a Methyl Group to the β-Position upon the CD Spectra of DNP Derivatives of Aromatic α-Amino Acids
Authors: Kawai Masao , Nagai Ukon , Tanaka Atsuko 
Published: July 2006

Abstract
CD spectra of N-DNP-O-benzoyl derivatives of l-serine, l-threonine, and l-allothreonine and DNP derivatives of l-phenylalanine and (βR)- and (βS)-β-methyl-l-phenylalanines were studied. The effect of methyl substitution at the β-position upon their CD spectra was explained by the change in the population of the rotamer g− (χ1=−60°) which was shown to be responsible for the characteristic negative Cotton effect at ≈400 nm. The negative sign of the [θ]≈400max values of the DNP derivatives of aromatic l-α-amino acids described by DNP-aromatic rule was proved to be due to the contribution of the rotamer g−.
A Convenient Method for Preparation of 2-(Methylthio)alkanoic Acids and Their Related Compounds Using the Carbanions of Substituted Malonic Esters
Authors: Ogura Katsuyuki , Itoh Hiroshi , Morita Toshio , Sanada Kunio , Iida Hirotada 
Published: July 2006

Abstract
Starting from alkyl- or aryl-substituted malonic esters prepared by various methods, 2-(methylthio)alkanoic acids are synthesized by successive treatment with sodium ethoxide and with S-methyl methanethiosulfonate, followed by alkaline hydrolysis which causes concurrent decarboxylation. Production of 2-(phenylthio)alkanoic acids is also achieved in a similar manner.
Mass Spectra of Furanoeremophilane Derivatives
Authors: Nagano Hajime , Kuroda Chiaki , Moriyama Yoshihiko , Tsuyuki Takahiko , Takahashi Takeyoshi 
Published: July 2006

Abstract
Mass spectral fragmentations of furanoeremophilane derivatives bearing oxygen-function on B ring were investigated. It was found that mass spectra measured by direct inlet system gave characteristic retro-Diels-Alder fragmentations, while indirect introduction of the samples afforded intense peaks at m/e 159 and m/e 145 containing the furan moiety. Fragmentation patterns of other poly-functional derivatives were examined by measurements of accurate masses and metastable ions.
Effects of Mechanical and Electrical Anharmonicities on Local Mode Spectrum
Authors: Tamagake Keietsu , Hyodo Shi-aki , Fujiyama Tsunetake 
Published: July 2006

Abstract
The first and second order dipole moment parameters along the CH bond in benzene, chloroform, and cyclohexane were obtained by deducing the local mode intensities on the basis of the one-dimensional Morse oscillator model. The validity of the one-dimensional model is discussed according to a newly introduced formula which helps us to understand the nature of local mode absorptions. The relative intensities of the first overtones to the other bands were found to be crucially important in determining M2/M1 together with its sign, because the contributions of the mechanical and electrical anharmonicities to M1/M2 are often cancelled out each other accidentally. The M2/M1 values for benzene, cyclohexane, and chloroform were 2.3, 1.45, and −0.93 Å−1 respectively. These values for benzene and cyclohexane were excellently reproduced by the ab initio calculations for benzene and methane respectively.
Salting-out Phenomenon and Clathrate Hydrate Formation in Aqueous Solution of Polar Nonelectrolyte
Authors: Kato Tadashi , Yudasaka Masako , Fujiyama Tsunetake 
Published: July 2006

Abstract
The Salting-out Phenomenon has been carefully observed by adding ammonium chloride into aqueous solutions of t-butyl alcohol, acetone, dioxane, and 2-butoxyethanol. The experimental results have been well explained by considering the formation of a clathrate hydrate-like local structure in the aqueous solution of each nonelectrolyte. In addition, the role of the chloride ion has been found to be the promotion of the aggregation of the clathrate hydrate-like local structures. The line-width measurement of 35Cl-NMR spectra has been shown to be an extremely powerful method for studying the state of mixing of ions in solutions.
An Ion-impact Study of Singlet-Triplet Transitions in Ethylene and Alkyl-substituted Ethylenes
Authors: Sato Yukinori , Satake Kazuki , Inouye Hokotomo 
Published: July 2006

Abstract
The T←N (π→π*) transitions in ethylene, all of its methyl derivatives, and 1-butene were observed by means of He+-impact energy-loss spectroscopy. With a resolution of better than 0.1 eV, a vibrational structure was just resolved in the T←N excitation spectrum of ethylene. The T←N transition energy was measured for the alkylethylenes with a lower resolution. The results are in good agreement with the electron-impact data, indicating that the vibro-rotational excitation due to the impulsive momentum transfer is negligible in the present method. The T←N excitation cross-sections were found to decrease by half upon the unit substitution of alkyls. The relative invariance of the T←N transition energy and the decrease in the T←N cross-sections upon alkyl substitution may be attributable to the decrease in the intra- and intermolecular Coulomb and exchange interactions between π- and π*-orbitals.
The Raman Spectra of Cobalt(III) Complexes. IV. Differentiation between cis and trans Isomers of Bis(trimethylenediamine)cobalt(III) Complexes
Authors: Kanamori Kan , Ichinose Hiroko , Kawai Kiyoyasu 
Published: July 2006

Abstract
The Raman and the infrared spectra of bis(trimethylenediamine)cobalt(III) complexes have been studied to establish a definite distinction between the cis and trans isomers. A differentiation between the isomers can be made on the bases of the number of the Raman bands in the region of 480–550 cm−1 and of the mutual exclusion in the region of 400–500 cm−1.
Calculation of the Pair Correlation Functions for Fluids Composed of Diatomic Polar Molecules Based on the Interaction Site Model
Authors: Ohba Masaharu , Arakawa Kiyoshi 
Published: July 2006

Abstract
A reference hypernetted chain (RHNC) like approximation of the interaction site model is proposed, which is the extension of Lado’s RHNC equation of simple fluids to the case of molecular fluids. By using the proposed RHNC like integral equation, pair correlation functions, structure factors and some thermodynamic quantities for fluids composed of diatomic polar molecules are calculated, where the molecules consist of two fused hardspheres with each center located at a distance l, and at each center charges +q and −q are sited. Calculated pair correlation functions are successful in showing well-marked characteristics of the fluid, such as cusps, not observed for simple fluids like argon. The isothermal compressibility at a constant reduced density and dipole moment has a weak l-dependence in sharp contrast to the total internal energy showing a strong l-dependence.
Effect of Polar Group on the Polypeptide–Lipid Interaction at the Air-Water Interface
Authors: Shibata Akira , Yamashita Shinsuke , Yamashita Takuya 
Published: July 2006

Abstract
The effect of polar group on the interaction of synthetic polypeptides with lipids at the air-water interface was investigated. Methyl stearate interacts with benzyloxycarbonyl derivative of basic poly(α-amino acid) or benzyl ester of acidic poly(α-amino acid) on distilled water and KF, KSCN, and urea subsolutions. No interaction between polypeptide and stearamide on various subsolutions was observed except for the mixed system of stearamide with benzyl ester of acidic poly(α-amino acid) in α-helical conformation. The components in mixed monolayers exhibit characteristic miscibilities depending upon the flexibility of polymer side chain, the conformation of polymer and the steric factor of head group in lipid molecules. All of the mixed polypeptide–lipid monolayers spread on the subsolution containing SCN− as a breaker of water structure become miscible. The dipole-dipole interaction between stearamide and benzyl ester of acidic poly(α-amino acid) in α-helical conformation is weakened by the action of urea.
Isomerism of the Metal Complexes Containing Multidentate Ligands. IX. Structure of the meso Isomer of [Co(hexaen)]3+ (hexaen=1,4,7,10,13,16-Hexaazacyclooctadecane)
Authors: Yoshikawa Yuzo , Toriumi Koshiro , Ito Tasuku , Yamatera Hideo 
Published: July 2006

Abstract
The crystal and molecular structure of meso-[Co(hexaen)]Cl3 has been determined by single crystal X-ray diffractometry. The crystals are rhombohedral with space group R\bar3, a=9.2976(10), c=16.851(2) Å, and Z=3. The structure has been refined by least-squares calculations to an R value of 0.021 for 952 observed reflections. The complex ion has S6 symmetry. The Co–N distance is 1.9966(8) Å and the N–Co–N angle in the chelate ring is 83.62(3)°. The molecular dimensions are in good agreement with those obtained from the conformational analysis.
The Sensitization Effect in the Laser-induced Infrared Fluorescence Spectroscopy by Addition of a Second Component. II
Authors: Kagawa Yasuhiro , Higuchi Seiichiro , Tanaka Shigeyuki 
Published: July 2006

Abstract
A considerable degree of the sensitization is realized in the laser-induced infrared fluorescence spectra when some of the alkene compounds are mixed with an objective sample in the gas phase. This sensitization effect has been examined quantitatively for diethyl ether when ethylene or propylene is added as a second component. The 8.7 μm band of ether is used as a key band. The degree of sensitization is abruptly enhanced with lowering the concentration of diethyl ether, and at about 0.1 Torrt of the sample the intensities per unit concentration become about 150 and 50 times greater for ether–ethylene and ether–propylene systems, respectively compared with that without ethylene or propylene. A possibility of a new vibrational spectroscopy with high sensitivity and its applications to microanalysis are suggested.
Preparation, and Structural and Spectroscopic Characterization of Cobalt(III) Phosphine Complexes of the Type, [Co(CN)4−2n(acac)n(P)2](n−1)+ (acac=Acetylacetonate Ion, n=0,1,2, and P=P(CH3)x(C6H5)3−x, x=0,1,2,3)
Authors: Kashiwabara Kazuo , Katoh Katsuaki , Ohishi Tomoji , Fujita Junnosuke , Shibata Muraji 
Published: July 2006

Abstract
A series of the complexes, [Co(CN)4−2n(acac)n(P)2](n−1)+ (acac=acetylacetonate ion, P=P(CH3)x(C6H5)3−x) and several related complexes were prepared. For [Co(acac)2(P)2]+, the P(CH3)3 and P(CH3)(C6H5)2 complexes afford only the cis and the trans isomers, respectively, while the P(CH3)2(C6H5) complex forms both cis and trans isomers. No P(C6H5)3 ligand gave the bis(acac)-type complex. The trans isomers show a strong absorption band in the region of the first absorption band, which is assumed to involve charge transfer transitions between the cobalt(III) ion and a phosphine, while the cis isomers give usual absorption spectra, exhibiting the first d-d absorption band of medium intensity. The methyl and phenyl groups on a phosphorus atom in both cis and trans isomers show triplet signals in the 1H and 13C NMR spectra due to virtual coupling. A trans(P,P) configuration was assigned to all the complexes of [Co(CN)2(acac)(P)2] on the basis of the NMR and electronic spectra. For [Co(CN)4(P)2]−, a trans configuration was assigned from the electronic spectra.
Synthesis of Biotin-containing Peptides Representing the Biotin Binding Site of E. coli Acetyl–CoA Carboxylase
Authors: Kondo Hiroki , Moriuchi Fumio , Sunamoto Junzo 
Published: July 2006

Abstract
Two biotin-containing peptides, Ac–Met–Bct–Met–Met–OMe (1) and Boc–Met–Bct–Met–Met, that correspond to the local sequence of biotin carboxyl carrier protein subunit of E. coli acetyl–CoA carboxylase have been synthesized. The precursor tetrapeptide Boc–Met–Lys(Cbz)–Met–Met–OMe was prepared first by the stepwise elongation method and biotin was incorporated subsequently by the active ester method. Another biotin-containing peptide, HCO–Met–Bct–Met–Met–OMe, has also been prepared. Magnesium ion binding to peptide 1 in acetonitrile has been studied by means of 13C NMR spectroscopy. The metal interacts principally with the amide carbonyls rather than sulfide moieties, as deduced from a significant downfield shift of the former carbon signals in 13C NMR.
The Biosynthesis of Protoanemonin in Ranunculus glaber. The Pivotal Biosynthetic Intermediate and the Stereospecific Hydrogen Elimination from the Intermediate
Authors: Suga Takayuki , Hirata Toshifumi 
Published: July 2006

Abstract
The pivotal biosynthetic intermediate directly leading to protoanemonin was established to be 2-oxoglutarate on the basis of the labeling patterns in protoanemonin biosynthesized from sodium acetate-1-14C, sodium malonate-2-14C, sodium succinate-2,3-14C2, sodium glutamate-5-14C, and sodium 2-oxoglutarate-5-14C by Ranunculus glaber. Also the 3H/14C ratio in protoanemonin biosynthesized from (3R)-2-oxoglutaric-3-3H1-3,4-14C2 and 2-oxoglutaric-3-3H2-3,4-14C2 acids demonstrated that the formation of the double bond at the 3-position of protoanemonin involves the stereospecific elimination of the pro-3S hydrogen atom from 2-oxoglutaric acid.
The Total Syntheses of (−)-Occidentalol and Its C7-Epimer. The Stereochemical Assignment of (+)-Occidentalol
Authors: Ando Masayoshi , Asao Toyonobu , Nakagawa Toru , Nanaumi Ken , Takase Kahei 
Published: July 2006

Abstract
The total syntheses of (−)-occidentalol and its C7-epimer are reported with the object of establishing the structure of naturally occurring (+)-occidentalol.
A Convenient Synthesis of 4- and 5-Acetyltropolone
Authors: Yamamoto Hiroshi , Hara Atsushi , Noguchi Ayashi , Kawamoto Heizan , Inokawa Saburo , Nozoe Tetsuo 
Published: July 2006

Abstract
4-Acetyltropolone is derived from hinokitiol (β-thujaplicin) in four steps, with an overall yield of 60%, via readily available 8-azidohinokitiol. γ-Thujaplicin almost quantitatively forms its difluoroboron complex, which, upon bromination, provides an 85% yield of the 8-bromo-γ-thujaplicin difluoroboron complex. This bromo compound readily gives γ-dolabrin (87% with triethylamine) and 8-azido-γ-thujaplicin (88% with sodium azide), from which 5-acetyltropolone is derived in an 80% yield by ozonolysis or in a 40% yield with sulfuric acid. The considerable differences in the reactivities observed between these 4- and 5-substituted tropolones are discussed. The pKa values of 4- and 5-acetyltropolone and 4- and 5-(3,4,5-trimethoxycinnamoyl)tropolones are also reported.
Electron Spin Resonance Studies of Manganese(II) Doped in Cd(NH3)2Ni(CN)4·2C6H6. Angular and Temperature Dependency of Fine Structures
Authors: Nakano Taku 
Published: July 2006

Abstract
ESR measurements on Mn(II) ion doped in single crystals of Cd(NH3)2Ni(CN)4·2C6H6 confirmed the structure of the Hofmann-type clathrate predicted before. Spin Hamiltonian parameters obtained are g=2.0033±0.0010, A=(−84.9±1.0)×10−4 cm−1 (123 K) and (−84.3±1.0)×10−4 cm−1 (room temp), D=(67.5±1.0)×10−4 cm−1 (123 K) and (17.3±1.0)×10−4 cm−1 (room temp), and a=(16.5±1.0)×10−4 cm−1. The environment of Mn(II) ion has a tetragonally distorted cubic symmetry. While the parameter a is independent of temperature, the parameter D is found to be dependent on temperature obeying to D∝(T0–T)2 where T0 is 473 K. The nuclear forbidden lines, Δm=±1, were also detected, intensities of which vary in terms of D squared.
Solvent Effect on the Nonradiative Deactivation of the Excited State of Tris(2,2′-bipyridyl)ruthenium(II) Ion
Authors: Nakamaru Katsumi 
Published: July 2006

Abstract
Emission quantum yields and lifetimes of the [Ru(bpy)3]2+ ion were measured in various solvents at 25 °C. Nonradiative rate constants (knr) were calculated from these data. A plot of knr vs. the Gutmann’s acceptor number was found to be linear. This result can be explained in terms of the contributions of charge transfer to solvent (CTTS).
Chemical Property of 1-Dialkylamino-2-phenylthioethylene
Authors: Agawa Toshio , Ishikawa Minori , Komatsu Mitsuo , Ohshiro Yoshiki 
Published: July 2006

Abstract
The olefins which are vicinally substituted by amino and phenylthio groups showed the reactivity as an enamine in the reactions with heterocumulenes and in cycloadditions with a 1,3-dipole and a 2-propenimine, giving a pyrazole derivative and a pyridine derivative, respectively.
Photocatalytic Dehydrogenation of 2-Propanol over TiO2 and Metal/TiO2 Powders
Authors: Teratani Shousuke , Nakamichi Junichi , Taya Kazuo , Tanaka Kazunori 
Published: July 2006

Abstract
A series of TiO2 catalysts loaded with transition metals were prepared by photodeposition. The activity order for these catalysts in the title reaction was as follows: Pt/TiO2&gt;Rh/TiO2&gt;Pd/TiO2&gt;Ru/TiO2&gt;Ir/TiO2&gt;TiO2. Upon heat treatment the activities of all the metal/TiO2 catalysts were enhanced, but the above sequence was unaltered.
Liquid Crystal Formation in Binary Systems. V. Liquid Crystals Induced in N-[4-(Dimethylamino)benzylidene]-4-ethoxyaniline-N-(4-Nitrobenzylidene)-4-nitroaniline and Related Mixtures
Authors: Araya Kotaro , Matsunaga Yoshio 
Published: July 2006

Abstract
The induction of liquid crystals was demonstrated with binary mixtures comprising N-(4-nitrobenzylidene)-4-nitroaniline and N-[4-(dimethylamino)benzylidene]-4-alkoxyaniline or N-(4-alkoxybenzylidene)-4-(dimethylamino)aniline. Both nematic and smectic phases were observed with the ethoxy derivatives, but only a smectic A phase with the propoxy derivatives. The mesophases appear in the region centered around 30 mol% of the dinitro compound. Similarly, liquid crystals could be induced in several mixtures of N-[4-(dialkylamino)benzylidene]-4-(dialkylamino)aniline with N-(4-nitrobenzylidene)-4-alkoxyaniline or N-(4-alkoxybenzylidene)-4-nitroaniline. The bis(dialkylamino) and dinitro derivatives of azoxybenzene were also shown to be efficient as one of the component compounds in producing binary liquid crystals.
Selective Reduction of Nitrogen Monoxide with Hydrogen on Pt/Al2O3 Containing a Metal Oxide
Authors: Kosaki Yukio , Miyamoto Akira , Murakami Yuichi 
Published: July 2006

Abstract
By using a three-way catalyst containing a metal oxide, NO can be selectively converted to N2 and N2O without the formation of NH3 even at the “rich” side of the air/fuel ratio. In order to elucidate the mechanism of this action of the added metal oxide, the NO–H2 reaction on Pt–V2O5/Al2O3 catalyst was investigated using the pulse reaction technique. In the NO–H2 reaction on Pt/Al2O3 catalyst, a significant amount of NH3 was formed in the “rich” region of the reactants (H2/NO&gt;1), although NO was completely removed. In the NO–H2 reaction on the Pt–V2O5/Al2O3 catalyst, on the other hand, no NH3 was formed even in the “rich” region of the reactants; in addition, NO was completely removed. During the NO–H2 reaction on the Pt–V2O5/Al2O3 catalyst, the V2O5 in the catalyst was found to be reduced from V5+ to V4+. The reaction of NO with NH3 and the reaction of NH3 or H2 with Pt–V2O5 mixed catalysts for various states of mixing were also investigated. From these results, the NO–H2 reaction on the Pt–V2O5/Al2O3 catalyst has been shown to be composed of the following three main steps: Step I, the formation of NH3 by the reduction of NO with H2 on Pt; Step II, the NO–NH3 reaction on Pt to form N2 or N2O; and Step III, the reduction of V2O5 in the catalyst by H2 which is accelerated by the “hydrogen spil-lover.” In the NO–H2 reaction on Pt/Al2O3 catalyst, NO is first reduced to NH3 in Step I and the NO–NH3 reaction in Step II follows. In the “rich” region, the formation of NH3 takes place more readily than the subsequent NO–NH3 reaction. In the NO–H2 reaction on the Pt–V2O5/Al2O3 catalyst, the formation of excess NH3 is suppressed by the removal of hydrogen from Pt in Step III, and the NH3 thus produced reacts with NO to form N2 or N2O selectively in Step II. The rates of Steps I, II, and III were also discussed in terms of the structure of the catalysts and composition of the reactants.
Electric Birefringence and Electric Dichroism of Sonicated DNA in Aqueous Solutions with Various Additives. Electro-optical and Hydrodynamic Properties
Authors: Matsuda Koichiro , Yamaoka Kiwamu 
Published: July 2006

Abstract
Electric birefringence (EB) and electric linear dichroism (ED) of a sonicated DNA (Mw=1.24×105) sample were studied in solutions containing various additives at 7 °C. Signals of EB at 535 nm and of ED at 260 nm were measured in the electric field range 0–ca. 19 kV/cm. Both signals obeyed the Kerr law at low field strengths (E&lt;ca. 5 kV/cm) and showed a saturating trend at high fields. The mean relaxation time, &lt;τ&gt;EB, obtained from the decay of EB, was field-strength dependent, indicating the effect of the polydispersity of sDNA. The field strength dependence of steady-state EB signals was nearly identical with that of ED signals. These results were analyzed with the “classical” orientation functions derived for mono- and polydisperse systems. The optical anisotropy factor (g3–g1) of sDNA was ca. −2.0×10−2, while the average angle between the orientation axis of sDNA and the transition moment of the base pair was ca. 70° at 260 nm. The electric moment of sDNA was influenced by ionic strength, counterions, and other additives. The weight-average length lw of sDNA decreased in this order: 0.2 mM NaCl**&gt;9-aminoacridinium chloride (P⁄D=10)&gt;1.0 mM NaCl&gt;0.33 mM MgCl2&gt; 20 vol% glycerol. Values of lw/base pair were 2.8−2.7 Å in the glycerol and 3.6−3.4 Å in the 1.0 mM NaCl.