bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Pressure on Iodine Complexes. II. Absorption Spectra of the Charge Transfer Bands with Diethyl Ether, Diethyl Sulfide, and Diethyl Selenide in Heptane
Authors: Sawamura Seiji , Taniguchi Yoshihiro , Suzuki Keizo 
Published: July 2006

Abstract
Absorption spectra of the CT bands of I2 complexes with Et2O, Et2S, and Et2Se in heptane have been measured up to 4400 bar at 25 °C. The equilibrium constants and the volume changes accompanying complex formation, and the molar extinction coefficients and absorption maxima have been estimated. The volume changes were comparable with those estimated by the visible I2 bands and by the X-ray data of the I2 complexes in the crystalline state. In the CT bands of Et2S–I2 and Et2Se–I2 complexes inversion of shift from red to blue has been observed with increasing pressure though the CT band of Et2O–I2 complex shifted only through red. This inversion appears to be characteristic of the strong CT complex. Enhancement of the molar extinction coefficient of the CT band has been found with increasing pressure suggesting enhancement of the CT interaction between I2 and the n-donor.
The Mechanism of Catalyzed Hydrogen–Deuterium Exchange on Gold Deposited over Poly(tetrafluoroethylene)
Authors: Iida Itsuo 
Published: July 2006

Abstract
The H2–D2 exchange reaction over Au(0.3%)/PTFE(poly(tetrafluoroethylene)) was studied. The apparent activation energy was found to be 29 kj mol−1. The dependence of the reaction rate on the total pressure was measured at 518, 432, and 393 K. It was found that the pressure exponent of the exchange reaction decreases with the increase in the total pressure and that in the lower pressure range, the reaction order is as high as 2. The rate equation obtained from the pressure dependence was R=k{KP⁄(1+KP)}2. Accordingly, it was concluded that the H2–D2 exchange reaction over gold takes place between molecularly adsorbed hydrogen and deuterium through a dimeric intermediate. The heat of adsorption on the active sites in the gold surface was 5.9 kj mol−1.
Studies on the Aqueous Solutions of Guanidinium Salt. XI. Volume Changes of Mixing of Aqueous Solutions of Guanidinium Bromide and Tetraalkylammonium Bromide at 25 °C
Authors: Miyajima Koichiro , Yoshida Hiromitsu , Nakagaki Masayuki 
Published: July 2006

Abstract
The volume changes on mixing aqueous solutions of guanidinium bromide with those of tetrabutyl- and tetramethylammonium bromide were measured with a vibration densimeter at 25 °C. The excess volume change of mixing was positive and large for the system of tetrabutylammonium bromide–guanidinium bromide–water. On the basis of the interaction parameters of Friedman’s formalism, this result was interpreted in terms of an interaction between guanidinium cation and tetrabutylammonium cation through the change of water structure.
Vapor Pressure Osmometry and Conductance Studies of Solutions of Bis(tetraalkylammonium) Electrolytes in Methanol, Ethanol, and 2-Propanol
Authors: Lee Ha Chung , Nomura Hiroyasu , Miyahara Yutaka , Verrall R E 
Published: July 2006

Abstract
Vapor-pressure depressions and electric conductivities have been measured for bis(tetraalkylammonium) electrolytes in methanol, ethanol, and 2-propanol. The analysis of the data of vapor pressure osmometry (VPO) of these bolaform salts was carried out taking into account the two-step dissociation equilibrium as follows.
M2++2X−\undersetKdI\ightleftarrowsMX++X−\undersetKdII\ightleftarrowsMX2
In each solvent, the ionic association constants, KaI and KaII (Ka=1⁄Kb), tend to decrease with increasing ionic size. This tendency is greater in KaI than in KaII. The KaII values of bis(tetraalkylammonium) electrolytes show virtually no dependence on the dielectric constant of solvent. On the contrary, the values of KaII strongly depend on the dielectric constant of solvent. Using the values of KaI and KaII in 2-propanol, the ultrasonic relaxation data were analyzed.
Potentialities of Field Desorption Mass Spectrometry Using Emitter Current Programmer for Direct Analysis of Multicomponents
Authors: Shiraishi Hiroaki , Otsuki Akira , Fuwa Keiichiro 
Published: July 2006

Abstract
The influence of emitter current on field desorption (FD) mass spectra was examined with use of an emitter current programmer (ECP). Reproducibility of FD mass spectra measured by electronic detection is improved with ECP and the integration of stored spectra on the computer. The FD mass spectra of some surfactants are shown as an example of complex mixture. The FD mass spectra of poly(oxyethylene) alkylphenyl ethers show that the distribution pattern of molecular ion peaks depends upon emitter current. The fractional desorption also occurs in the FD mass spectra of α-hydro-ω-(octadecylamino)poly(oxyethylene) measured with a constant emitter current. The emitter current required for desorption of hexadecyltrimethylammonium chloride is greatly affected by coexisting with another ammonium salt. Use of ECP supplies information on the analysis of multicomponents.
Use of a Programmable Monochromator and a SIT Detector in Flame Atomic Emission Spectrometry
Authors: Furuta Naoki , McLeod Cameron W , Haraguchi Hiroki , Fuwa Keiichiro 
Published: July 2006

Abstract
A multielement detection system which uses a programmable monochromator and a SIT image detector has been constructed, and evaluated by measuring the flame emission of 22 elements in the nitrous oxide–acetylene flame. The detection limits for the elements under optimized experimental conditions are reported, and are compared with those obtained by a standard photomultiplier tube.
Sodium Ion Exchange on Crystalline Zirconium Titanium Phosphate
Authors: Yazawa Yutaka , Eguchi Toru , Takaguchi Kazunori , Tomita Isao 
Published: July 2006

Abstract
A new ion exchanger, crystalline zirconium titanium phosphate with variable zirconium to titanium mole ratios has been prepared and the sodium ion exchange behavior studied. In the zirconium-rich exchanger a half-exchanged monosodium phase was produced. This differs from the titanium-rich exchanger where a disodium phase was formed without formation of the intermediate monosodium phase. The pH titration curves were complicated but a trend emerged with variation in the Zr/Ti ratio. On the basis of the X-ray evidence and the shapes of the titration curves it is thought that the synthesized phosphates are solid solutions rather than a mechanical mixture of the two metal phosphates.
Synthesis of 4-(Glycosyl)isoxazoline N-Oxides and Related Substances
Authors: Kaji Eisuke , Ichikawa Hiromi , Zen Shonosuke 
Published: July 2006

Abstract
4-(Glycosyl)isoxazoline N-oxides were synthesized directly from aldehydo sugars by one-step cyclization with double mole of methyl nitroacetate in a satisfactory yield. 2,3-O-Isopropylidene-d-glyceraldehyde reacted with methyl nitroacetate to give 4-(1,2-O-isopropylidene-d-glycero-dihydroxyethyl)-3,5-bis(methoxycarbonyl)isoxazoline N-oxide. The same treatment of 2,3 : 4,5-di-O-isopropylidene-aldehydo-l-arabinose and penta-O-acetyl-aldehydo-d-glucose also gave the corresponding homologs. From the corresponding cyclic aldehydo sugars, 4-aldofuranosyl-3,5-bis(methoxycarbonyl)isoxazoline N-oxides, e.g. 4-(2,3-O-isopropylidene-β-d-erythrofuranosyl)-, 4-[(4R)-3-O-benzyl-1,2-O-isopropylidene-β-l-threofuranos-4-yl]-, 4-(2,3,5-tri-O-benzyl-β-d-ribofuranosyl)-, and 4-(2,3,5-tri-O-benzoyl-β-d-ribofuranosyl)-derivatives were synthesized. The latter was converted into 3,5-dicarbamoyl-4-(β-d-ribofuranosyl)isoxazoline by deoxygenation followed by carbamoylation and deprotection.
Structural Studies of the Interaction between Indole Derivatives and Biologically Important Aromatic Compounds. IV. The Crystal and Molecular Structure of Tryptamine: Adenin-9-ylacetic Acid (1 : 1) Hemihydrate Complex
Authors: Ishida Toshimasa , Inoue Masatoshi , Senda Susumu , Tomita Ken-ichi 
Published: July 2006

Abstract
The crystal structure of tryptamine: adenin-9-ylacetic acid (1 : 1) hemihydrate complex has been determined by the X-ray method. The crystal is monoclinic, space group P21/c with unit-cell dimensions: a=9.164(2), b=6.908(1), c=29.524(4) Å and β=110.98(2)°. The structure was solved by application of MULTAN and refined by the block-diagonal least-squares method to give a final R-value of 0.064. No specific interaction between indole and adenine rings is observed. Both component molecules are held together by three-dimensional frameworks of hydrogen bonds around a twofold screw axis to form an infinite helical array along the b-direction. Two kinds of dimer formation around a center of symmetry are observed between adenin-9-ylacetic acid molecules.
Photochemical Reaction at 3-O-Functional Group of Methyl 4,6-O-CycIohexylidene-2-deoxy-2-methoxycarbonylamino-α-d-glucopyranoside Derivatives
Authors: Kishi Teruo , Tsuchiya Tsutomu , Umezawa Sumio 
Published: July 2006

Abstract
3-O-Acetyl, 3-O-thiocarbonyl, and 3-O-sulfonyl derivatives of the titled compound have been irradiated in aqueous HMPT. Conversion of the 3-O-acetyl derivative to the corresponding 3-deoxy compound was most effective. 3-O-Dimethylthiocarbamoyl-, 3-O-(methylthio)thiocarbonyl- and 3-O-(1-imidazolyl)thiocarbonyl derivatives were found to give the 3-deoxy compound accompanied by 3-hydroxy compound, whereas the 3-O-phenyl(thiocarbonyl) derivative did not give the 3-deoxy compound. 3-O-Methylsulfonyl and 3-O-tolylsulfonyl derivatives gave the 3-hydroxy compound. Under low-energy irradiation, the (1-imidazolyl)thiocarbonyl derivative gave the 3-deoxy compound in moderate yield.
A Kinetic Study of the Simultaneous Dealkylation and Disproportionation of Cumene over Silica–Alumina
Authors: Take Jun-ichiro , Tozawa Yoichi , Yoneda Yukio 
Published: July 2006

Abstract
Cumene has been passed over a silica–alumina bed at low temperature (210 to 254 °C) and at cumene pressures of 0.003 to 0.023 atm. Both dealkylation and disproportionation occurred simultaneously and independently of each other. The disproportionation/dealkylation ratio increased with decrease in temperature and/or an increase in cumene pressure. The dealkylation and disproportionation reactions followed a Langmuir-Hinshelwood model with inhibition by the reactant. The dealkylation has been interpreted in terms of a unimolecular surface reaction, while the disproportionation reaction in terms of a bimolecular surface reaction. The heat of adsorption of cumene and the entropy loss of cumene on adsorption were much larger for the dealkylation sites than for the disproportionation sites. These results indicated that dealkylation was catalyzed by strong acid sites, while disproportionation by weak acid sites. The dealkylation had a much higher activation energy than the disproportionation reaction. The activation energy for dealkylation (33.5 kcal mol−1) was in good agreement with that predicted on the assumption that the previously reported LFER (linear free-energy relationship) in the alcohol dehydration holds for alkylbenzene dealkylation.
Structure of a New Ionone Derivative, Nigakialcohol from Picrasma ailanthoides Planchon
Authors: Sugimoto Yayoi , Sakita Takaaki , Ikeda Toru , Moriyama Yoshihiko , Murae Tatsushi , Tsuyuki Takahiko , Takahashi Takeyoshi 
Published: July 2006

Abstract
A new ionone derivative, nigakialcohol, was isolated from the leaves of Picrasma ailanthoides Planchon (Simaroubaceae), the structure being found to be (4R,5S)-4-[(R)-3-hydroxybutyl]-5-hydroxymethyl-3,3-dimethyl-1-cyclohexanone. Nigakilactones E, F, and H and vomifoliol were also isolated from the leaves.
The Transformation of 11-Deoxojervine into 18-Functional C-Nor-D-homosteroids
Authors: Suginome Hiroshi , Sato Norio , Masamune Tadashi 
Published: July 2006

Abstract
Deoxojervine, a C-nor-D-homosteroidal alkaloid, has been transformed into 17β-acetyl-12α-etiojervan-3β-ol acetate in 3 steps. Treatment with base gave the 17α-epimer. Reduction of the 17β-isomer with NaBH4 afforded 17β-ethyl-12α-etiojervane-3β,20β-diol 3-acetate as a single product whereas reduction of the 17α-isomer afforded 17β-ethyl-12α-etiojervane-3β,20β-diol 3-acetate and the 20α isomer in an approximate 1 : 1 ratio. Irradiation of 17β-ethyl-12α-etiojervane-3β,20β-diol 3-acetate in cyclohexane in the presence of lead tetraacetate and iodine afforded a C-18 functional C-nor-D-homosteroid as a 18,20-epoxide which was oxidized to the corresponding γ-lactone with chromium trioxide. A mixture of the 17α-ethyl-12α-etiojervane-3β,20α-diol 3-acetate and its 20β isomer in contrast gave no 18-functional compounds upon irradiation under similar conditions.
Aminosugars. XXXI. Preparation of Benzyl 2-Acylamino-4-azido-2,4-dideoxy-ribo- and -lyxopyranosides by Inversion of Hydroxyl Group on C-3
Authors: Hashimoto Hironobu , Araki Koichi , Yoshimura Juji 
Published: July 2006

Abstract
Benzyl 2-acylamino-4-azido-2,4-dideoxypentopyranosides having α-d-ribo, β-l-ribo, α-d-lyxo, and β-l-lyxo configurations were derived from the corresponding α-d-xylo, β-l-xylo, α-d-arabino, and β-l-arabino isomers, respectively, by inversion of hydroxyl group on C-3. Displacement reaction of sulfonyloxy group with sodium acetate or benzoate in aqueous 2-methoxyethanol or anhydrous N,N-dimethylformamide, or oxidation-reduction method via ulose derivative was used properly according to the stereochemistry of the starting materials.
Vapor-phase Hydrolysis of Chlorobenzene Catalyzed by Copper(II) Ion-exchanged Zirconium Phosphate
Authors: Izumi Yusuke , Mizutani Yukio 
Published: July 2006

Abstract
Copper(II) ion-exchanged zirconium phosphate (ZP–Cu(II)) effectively catalyzed the vapor-phase hydrolysis of chlorobenzene to phenol at 450 °C under atmospheric pressure. Per-pass conversion of chlorobenzene was between 12 and 18% with selectivity for phenol from 90 to 95 mol %. The catalytic activity was influenced by the content of copper, the ratio of phosphate to zirconium, and the pH at which copper(II) ions were introduced into zirconium phosphate. ZP–Cu(II) catalyst was amorphous and it turned inactive by thermal treatment at above 800 °C, resulting in a crystalline substance. The active site of ZP–Cu(II) for this hydrolysis reaction appears to be the phosphate groups of ZP bearing copper(II) ion. The reaction seems to proceed via a Rideal mechanism in which an adsorbed chlorobenzene molecule reacts with water in the vapor phase at the catalyst surface. The desorption of hydrogen chloride was rate controlling.
Theoretical Studies of Some Nonbenzenoid Hydrocarbons. V. Benzazulenes and Benzofluoranthenes
Authors: Das Gupta Archana , Chatterjee Subrata , Das Gupta Nanda K 
Published: July 2006

Abstract
The molecules benzazulenes and benzofluoranthenes have been studied by the semi-empirical method for π-molecular systems, similar to that of Pariser-Parr and Pople. Ground state properties and π*←π spectra have been predicted and compared with experiment. Agreement between the theoretical values and observed ones is good; that between the experimental value of half-wave reduction potential and values calculated by SCF(d) method is very good.
Thermochemistry of Copper(II) β-Diketonates, II. Bis(benzoylacetonato)copper(II)
Authors: Da Silva Manuel A V Ribeiro , Reis Ana Maria M V 
Published: July 2006

Abstract
The standard enthalpy of formation of crystalline bis(benzoylacetonato)copper(II) has been determined at 298.15 K by solution calorimetry: ΔHf°[Cu(bzac)2] (c)=−143.6±2.2 kcal mol−1. Enthalpy changes at 298.15 K for the following hypothetical gaseous reactions have been subsequently derived:
Cu(g)+2bzac·(g)=[Cu(bzac)2](g) ΔH=−165.9±14.3 kcal mol−1
Cu2+(g)+2bzac−(g)=[Cu(bzac)2](g) ΔH=−747.3±14.4 kcal mol−1
The corresponding homolytic(\barE) and heterolytic(\barE′) copper(II)-oxygen mean bond energy parameters were calculated as
\barECu-o=41±3 kcal mol−1 and \barE′Cu-o=187±3 kcal mol−1
respectively.
Reactions of 2-Ethoxycarbonyl-1,3-indandione with Aromatic Amines, Diazonium Salts, and Phenols
Authors: Afsah El-Sayed , Zimaity Tawfik 
Published: July 2006

Abstract
2-Ethoxycarbonyl-1,3-indandione (1) was treated with primary aromatic amines in acetic acid to afford 3-hydroxy-1-(arylimino) derivatives (2). Treatment of 1 with excess p-toluidine gave 3-tolylimino-4′-methyl-in-dancarboxanilide (3). With o− or p-phenylenediamine it yielded 3,3′-dihydroxy-1′-(o- or p-phenylenedinitrilo)di-2-indenecarboxylate. The tetraazacycloeicosene derivative was obtained by the action of p-phenylenediamine on 1 in a 1:1 molar ratio. In boiling toluene 1 gave the corresponding 2-carboxanilides (8) which cyclized to the diazepinone or to the quinolone. The coupling of 1 and 8 with diazonium salts was also investigated. The condensation of 1 with phenols afford 14, which were hydrolysed to 3-aryl-1-indenones.
A Synthetic Method for N-Benzyloxycarbonyl Hydroxy Amino Acid t-Butyl Esters
Authors: Kinoshita Hideki , Ishikawa Hajime , Kotake Hiroshi 
Published: July 2006

Abstract
A preparative method for the N-benzyloxycarbonyl hydroxy amino acid t-butyl esters using the aceto-acetyl group as a protecting group for the hydroxyl group of hydroxy amino acids is described. The acetoacetyl group is readily introduced into the hydroxyl group with diketene and effectively deprotected from the O-protected compounds using hydrazine.
Novel Lactonization of γ-Cyclopropyl Carboxylic Acid via Acid-catalyzed Cleavage of Cyclopropane Ring
Authors: Sekizaki Haruo , Ito Masaaki , Inoue Shoji 
Published: July 2006

Abstract
4,6,10,l0-Tetramethyltricyclo[4.4.0.01,3undec-4-ene-5-carboxylic acid has been converted to a tricyclic γ-butyrolactone by perchloric acid catalyzed isomerization. Acetalization of the ketocarboxylic acid afforded an acetal derivative of γ-butyrolactone.
Notiz über die Säurekatalysierte Umwandlung von 7a-Methyl-5,6,7,7a-tetrahydroindan-1,5-dion in 1-Methylbrexan-4,9-dion
Authors: Kobayashi Makoto , Minami Takashi , Matsumoto Takeshi 
Published: July 2006

Abstract
Beim Erhitzen in HCO2H mit Mineralsäure wurde 7a-Methyl-5,6,7,7a-tetrahydroindan-1,5-dion sauer katalysiert in 1-Methylbrexan-4,9-dion umgewandelt. Ein Zwischenprodukt, 7a-Methylhexahydro-2-inden-1,5-dion konnte gaschromatographisch abgetrennt werden.
Enantioselective Alkylation Using Optically Active Phase Transfer Catalyst
Authors: Saigo Kazuhiko , Koda Hiroshi , Nohira Hiroyuki 
Published: July 2006

Abstract
Synthesis of optically active benzyl[cis-2-(hydroxymethyl)cyclohexyl]dimethylammonium bromide (3) and its application to asymmetric synthesis were studied. It was found that 3 was as effective as (−)-N-benzyl-N-methylephedrinium bromide in the enantioselective alkylation of active methylene compounds when it was employed as a chiral phase transfer catalyst.
Methylation of Purine 2′-Deoxynucleosides with Trimethyl Phosphate
Authors: Tanabe Toshizumi , Yamauchi Kiyoshi , Kinoshita Masayoshi 
Published: July 2006

Abstract
Trimethyl phosphate was found to methylate deoxyadenosine (N-1) and deoxyguanosine (N-1, N-7, and O-6) in a homogeneous aqueous phase at 37 and 60 °C, giving the corresponding methyl derivatives.
Mesomorphic 4-Alkylphenyl 4-Benzoyloxybenzoate Bearing a Terminal Vinyl Group
Authors: Kamogawa Hiroyoshi , Sekigawa Masayuki , Nakano Tomohiro , Izawa Shin , Nanasawa Masato 
Published: July 2006

Abstract
4-Alkylphenyl 4-(4-vinyl-, methacryloyloxy-, and methacrylamido-benzoyloxy)benzoates have been synthesized by the reactions of 4-alkylphenyl 4-hydroxybenzoates with the corresponding substituted benzoyl chloride in pyridine. The mesomorphic ranges of these novel monomers are highly dependent upon the type of substituent at both ends of the molecules.
A New Triterpene Glucoside from Terminalia arjuna. Arjunglucoside III
Authors: Tsuyuki Takahiko , Hamada Yuriko , Honda Tadashi , Takahashi Takeyoshi , Matsushita Kazuhiro 
Published: July 2006

Abstract
The structure of a new triterpene glucoside, arjunglucoside III, isolated from Terminalia arjuna was found to be β-d-glucopyranosyl 2α,3β,19α-trihydroxy-11-oxoolean-12-en-28-oate.
Adsorption of Water on FeOOH as Studied by Electrical Conductivity Measurements
Authors: Kaneko Katsumi , Inouye Katsuya 
Published: July 2006

Abstract
Changes in the electrical conductivity of synthetic α-, β-, and γ-FeOOH crystals with the amount of adsorbed water were measured at 30 °C and various frequencies (dc, 100–10 MHz). The conductivity variations of wateradsorbed FeOOH with temperature were also examined over the range from −140 to 140 °C. For the adsorption coverages between 0 and 0.5, the electronic conduction increased with the coverage due to the transfer of electrons from chemisorbed water molecules to the FeOOH crystal. The decrease in activation energy for conduction with chemisorption was observed. The conductivity increase due to the chemisorption is related to the characteristic surface structure of each FeOOH polymorph. In the coverage range 0.7–2, protons in the adsorbed water layer transport electrical charges. The linear relationships between the logarithm of conductivity and the logarithm of the relative pressure of water vapor suggest the presence of clusters of physisorbed water molecules on FeOOH surfaces. A steep change in protonic conductivity by a factor of 102–104 was observed at a temperature close to −5 °C. The change seems to be caused by an order-disorder transition of protons in the adsorbed water layer.
ESR Study of SeO2− Radical in an Irradiated Single Crystal of Triglycine Selenate in the Vicinity of Phase Transition Temperature
Authors: Kotake Yashige , Kuwata Keiji 
Published: July 2006

Abstract
Detailed observations of the angular dependence of ESR spectra of SeO2− radicals formed by X-ray irradiation of a single crystal of ferroelectric triglycine selenate were carried out. Two kinds of SeO2− radicals were produced due to the difference in manner of selenium-oxygen bond scission. In spite of the difference in stability of radicals in TGSe and those in TGS, the behavior of SeO2− radicals in the phase transition region is in line with that expected from the result of X-ray diffraction study of TGS.
Ab initio LCAO MO SCF CI Calculations on the Electronic Structure of the Cyclopropenyl Cation
Authors: Takada Toshikazu , Ohno Kimio 
Published: July 2006

Abstract
Ab initio LCAO MO SCF and limited CI calculations are carried out on the electronic structure of the C3H3+ ion. Two kinds of basis sets are used, namely the minimal STO’s and the minimal STO’s plus 3d orbitals on each carbon atom. With the latter basis, the equilibrium C–C distance is calculated to be 1.389 Å. It is predicted that the C–C bond distance of C3H3+ is shorter than that of C6H6. The calculated C–C stretching force constant is 7.92 mdyn/Å and is close to the experimental value 6.59 mdyn/Å. Contour diagrams of the charge distribution of valence electrons are drawn and it is revealed that the calculated C–C bonds are bent and have two maxima in charge density. In terms of population analysis of localized MO’s, it is shown that the C–H bond in this molecule has a higher s-character than the C–H bonds in C2H4 and C6H6 and is close to an sp hybrid. This is in accord with a very large NMR coupling constant J13C–H. From CI calculations of low lying excited states, singlet σ-π* states (1A1″, 1E″, 1A2″) are calculated to be lower than the singlet π-π* state (1E′).