bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Laser-flash Photolysis of Propanone, Butanone, and 2-Pentanone. Study of Triplet Decay Processes in Aliphatic Carbonyl Compounds
Authors: Naito Ikuo , Schnabel Wolfram 
Published: July 2006

Abstract
The laser-flash photolysis of propanone, butanone, and 2-pentanone were carried out in dichloromethane (265 nm, 15 ns flash duration). The emission spectra (fluorescence, phosphorescence, and P-type delayed fluorescence) and the transient absorption spectra (triplet state and acetyl radical) were recorded. From the decays of the emission and the absorption, the unimolecular (triplet decay) and bimolecular (T–T annihilation and self quenching) reaction-rate constants were determined. Oxygen quenched the triplet states with a diffusion-controlled rate constant (kO2=ca. 3×10 dm3mol−1 s−1).
Studies of Bitter Peptides from Casein Hydrolyzate. IX. Syntheses and Bitter Taste of Bitter Peptide BPIa Dimer, (Arg–Gly–Pro–Pro–Phe–Ile–Val)2, and Gly–Gly BPIa Derivatives
Authors: Miyake Ichizo , Kouge Katsushige , Kanehisa Hidenori , Okai Hideo 
Published: July 2006

Abstract
In order to elucidate the relationship between taste exhibition and chemical structure of bitter peptide BPIa, di–BPIa, Gly–Gly–BPIa, BPIa–Gly–Gly, and Gly–Gly–BPIa–Gly–Gly were synthesized. All of the peptides possessed a strong bitter taste of the same level as that of BPIa. In addition, the CD curves of the peptides were similar to that of BPIa. The results suggested that their spatial structures are essentially similar and that the whole molecular shape of BPIa contributes to its bitterness.
Specific Generation of Lithiated 3-Trimethylsiloxy-1,2-propadiene Derivatives from 1-(Trimethylsilyl)propargyl Alcohols
Authors: Kato Masahiro , Kuwajima Isao 
Published: July 2006

Abstract
1-(Trimethylsilyl)propargyl alcohols have been prepared by treating acyltrimethylsilanes with magnesium acetylides, and their base-induced reactions involving rearrangement of silyl group have been examined. Treatment of the alcohol with an equimolar amount of butyllithium in hexane followed by addition of tetrahydrofuran has allowed to generate the lithiated 3-trimethylsiloxy-1,2-propadiene, which reacts with an alkyl iodide to afford the alkylated 1-trimethylsiloxy-1,2-propadiene in high yield. Further, a catalytic amount of butyllithium also effects an efficient conversion of the alcohol to the corresponding 1-siloxy-1,2-propadiene through a similar rearrangement process.
A Consideration on the Structure of the Nascent Fibril Produced by Acetobacter xylinum
Authors: Kai Akira 
Published: July 2006

Abstract
The structure of the nascent fibril produced by Acetobacter xylinum was examined by electron microscopy and resistance to alkali. It was found that the inner part of the fibril after production is stained uniformly with sodium tungstophosphate. This suggests that the nascent fibril is in an amorphous state. Moreover, the fact that in the amorphous fibril microscopic fibrils with closely similar widths always appear in the course of time and that the X-ray diffraction diagram of the never-air-dried fibril treated with 11 wt% aqueous NaOH solution show cellulose I not cellulose II diffraction patterns, indicate that the arrangement of cellulose chains in its cross section can transform easily to that of chains in ellulose I crystalline. For such an arrangement, it must be presumed that in the nascent fibril cellulose chains are in the form of sheets of monomolecular layers corresponding to the (1\bar10) plane of cellulose I crystalline.
Silent Electric Discharge in the Equimolar Dihydrogen-Carbon Monoxide Mixture
Authors: Hata Sintaro , Hiramoto Koji , Katoh Katsuaki , Sasaki Kazuo 
Published: July 2006

Abstract
The purpose of this paper is focused on seeking the possibility of utilizing electric discharge in H2–CO mixtures as a mean of industrial processes. Along this line, the silent discharge in the equimolar mixture of CO and H2 has been studied as a function of both the flow rate of reacting gas mixture and the length of the discharge tube. The yield of formaldehyde, the main product, increased t with increasing flow rate of gas. At a given flow rate, however, the yield increased with increasing tube length indicating that the selectivity of formaldehyde can be increased steadily by increasing the rate of gas flow. The best value of the formaldehyde selectivity was 34% at the shortest residence time (0.25 s). Improvement of this value seems to be promising.
A Novel Beckmann Fission Reaction of 2-Aminocyclohexanone Oxime
Authors: Sato Haruyo , Imamura Shinzo , Kitano Yukishige 
Published: July 2006

Abstract
2-(4-Cyanobutyl)-4,5,6,7-tetrahydrobenzimidazole was obtained by treating 2-aminocyclohexanone oxime with ethyl acetimidate hydrochloride in acetic acid at below 50 °C, though only 2-methyl-4,5,6,7-tetrahydrobenzimidazole was produced by the reaction of 2-aminocyclohexanone oxime and free ethyl acetimidate in neutral solvents. A novel Beckmann fission reaction of dimeric 2-aminocyclohexanone oxime is presumed to participate in the formation of 2-(4-cyanobutyl)-4,5,6,7-tetrahydrobenzimidazole.
Chemical-state Analysis by Means of Soft X-Ray Spectroscopy. II. Kβ Spectra for Phosphorus, Sulfur, and Chlorine in Various Compounds
Authors: Taniguchi Kazuo 
Published: July 2006

Abstract
The phosphorus-, sulfur- and chlorine-Kβ spectra in various compounds are obtained by means of secondary excitation using a simple quasi-two-crystal X-ray spectrometer. The spectra thus obtained change depending upon the chemical state. The spectra are discussed from the point of view of chemical-state analysis. The spectral features are especially influenced by the hydrogen and oxygen of the ligand. The peak on the lower-energy side appears to be related to the oxygen, and the peak grows with an increase in the oxidation number. The spectrum gives information on the structural formula.
Nonisothermal Crystallization of Poly(tetrafluoroethylene)
Authors: Ozawa Takeo 
Published: July 2006

Abstract
Crystallization of poly(tetrafluoroethylene) was observed by differential scanning calorimetry at constant cooling rates. A method for kinetic analysis of thermoanalytical data of nonisothermal crystallization was applied to analyze the data, and it was elucidated that poly(tetrafluoroethylene) crystallizes one-dimensionally from preexisting nuclei, which are presumably impurities. These results are in accordance with electron-microscopic observation of the crystalline morphology of poly(tetrafluoroethylene), which consists of band-like or star-like crystallites. The kinetic parameters, especially the temperature dependence of the linear growth rate, were estimated.
Furan Ring Formation in OH-initiated Photooxidation of 1,3-Butadiene and cis-1,3-Pentadiene
Authors: Ohta Tomohiro 
Published: July 2006

Abstract
Reactions of hydroxyl radicals with 1,3-butadiene and cis-1,3-pentadiene in the presence of oxygen were studied in the gas phase. Two OH radical sources were employed; photolysis of H2O2 at 254 nm and photolysis of methyl nitrite at 360 nm. In the reaction system for 1,3-butadiene, furan was detected besides acrylaldehyde and in the cis-1,3-pentadiene system, 2-methylfuran was detected besides acetaldehyde, acrylaldehyde, and crotonaldehyde by gas chromatographic analysis. Approximate yields of furan and 2-methylfuran were 5.3–6.7% and 6.7–8.4%, respectively, which were sensitive to the conditioning of the surface of reactor but insensitive to hydroxyl radical sources, the surface material of reaction vessel or the surface to volume ratio of reactors. The yields of aldehydes were also measured. Isotopic labeling experiment with 18O2 by use of mass spectrometry indicated that abstraction of vinyl–hydrogen from 1,3-butadiene and cis-1,3-pentadiene occurred about 3% of the time. Photooxidation of 2,5-dihydrofuran initiated with ·OH radicals was also discussed to explain the increase of furan in the dark after the irradiation.
Adsorption Properties of Pillar Interlayered Montmorillonite
Authors: Matsumoto Mutsuyoshi , Suzuki Minoru , Takahashi Hiroshi , Saito Yasukazu 
Published: July 2006

Abstract
From analyses of Langmuir-type isotherms and αs-plots for nitrogen adsorption, both the micropore volume and the external surface area have been determined for pillar interlayered montmorillonite (abbreviated as PILM) prepared by intercalating the polynuclear Al cation into the montmorillonite interlayer. The applicability of the Gurvitsch rule to microporous PILM samples was confirmed for adsorption of heptane, whereas the adsorbed amounts of polar adsorbates were dependent on dehydrated states of the alumina pillar. High density of benzene in the micropore independent of calcination temperature suggests some peculiar orientation of benzene in the adsorbed state due to its molecular shape. The interaction of a water molecule with the adsorption site is weak and dependent on the calcination temperature of PILM samples. On this basis, the inhibition of rehydration of the alumina pillar has been discussed.
Basic Properties of MgO Doped with Alkaline Metal Compounds
Authors: Matsuda Tsuneo , Sasaki Yo , Miura Hiroshi , Sugiyama Kazuo 
Published: July 2006

Abstract
Basic properties of MgO doped with NaOH, KOH, and Li2CO3 which was calcined at 550, 700, and 900 °C in air were examined. The basicity of the catalysts was determined from the irreversible amount of adsorption of phenol and BF3, followed by evacuation at room temperature (for both adsorbates), 100, 200, and 300 °C (for phenol) after adsorption at room temperature. A good correlation was observed between the amount of phenol remained after evacuation at higher temperature than 200 °C and that of BF3. By doping of 1 wt% of alkali metal compounds in MgO the isomerization activity of 1-butene was enhanced, but by 10 wt% the activity remarkably decreased.
An Inspection of the Purity of Helium Used as the Carrier Gas in Pulse-adsorption Experiments
Authors: Miura Hiroshi , Narita Toshiyuki , Haruta Makoto , Sugiyama Kazuo , Matsuda Tsuneo 
Published: July 2006

Abstract
A novel method is proposed to inspect the oxygen content of the helium used as the carrier gas in pulse-adsorption experiments. The oxygen is first adsorbed on Pt/SiO2 catalyst and then titrated by CO pulses. This method is very simple and requires only a conventional pulse-adsorption system.
Tetrabromooxomolybdate(V) Complex. The Catalytic Reactivity for the Reaction of t-Butyl Hydroperoxide
Authors: Kurusu Yasuhiko , Masuyama Yoshiro , Saita Mikio 
Published: July 2006

Abstract
The nature of an ammonium counter cation of tetrabromooxomolybdate complex influences the rate of decomposition of t-butyl hydroperoxide(t-BuOOH) and oxidation with t-BuOOH. The catalytic activity of the ammonium for the decomposition of t-BuOOH decreased as the following order; benzyltrimethylammnium, –N-methyl pyridinium, –trimethylene bispyridinium, &gt;&gt;pyridinium, –quinolinium, &gt;1,3-propanediammonium, −1,6-hexanediammonium. However, the reverse order was observed in the catalytic activity for the epoxidation by t-BuOOH, and the rate of oxidation of alcohol by t-BuOOH was independent of the nature of ammonium cation.
The Syntheses of the Corticoid Side-chain. II. A New Synthesis of 17α,21-Dihydroxypregna-1,4-diene-3,20-dione 21-Acetate from 21-Hydroxy-20-methylpregna-1,4-dien-3-one
Authors: Nitta Issei , Haruyama Toshio , Fujimori Shinichiro , Inoue Shinya , Ueno Hiroaki 
Published: July 2006

Abstract
17α,21-Dihydroxypregna-1,4-diene-3,20- dione, a potentially useful intermediate of prednisolone, can be prepared from 21-hydroxy-20-methylpregna-1,4-dien-3-one, a biodegradation product of cholesterol.
Nonadiabatic Transitions in Photochemical Electrocydic Reaction of Acrylaldehyde to Form 2H-Oxete
Authors: Morihashi Kenji , Kubota Hiroshi , Kikuchi Osamu 
Published: July 2006

Abstract
The photochemical electrocyclic reaction of s-cis-acrylaldehyde to form 2H-oxete was examined on the basis of the nonadiabatic interaction between potential energy surfaces. The nonadiabatic coupling g terms were calculated by the reduced classical-trajectory method along two postulated reaction paths, the concerted path and the step-by-step path. The calculated g terms were characteristic of the avoided crossing between the potential energy surfaces. The calculated g terms and the transition probabilities indicated that the step-by-step path was very efficient in the formation of 2H-oxete from the π–π* state of acrylaldehyde.
The Photochemical Magnetic Field Effect of Isoquinoline N-Oxides
Authors: Hata Norisuke 
Published: July 2006

Abstract
The irradiation of isoquinoline N-oxide in ethanol resulted in the formation of lactam in a ca. 67% yield via the S1 state (Process I). When the photochemical isomerization was carried out in the presence of a magnetic field, the chemical yield of lactam was found to show a minimum at approximately 1T. In order to interpret this new phenomenon, Process I was assumed to be initiated by electron transfer from the excited singlet N-oxide to the hydrogen-bonded ethanol (the formation of a singlet hydrogen-bonded radical ion pair). Thus, the new type of magnetic-field effect was excellently explained in terms of an electron-nuclear hyperfine interaction mechanism including the electron-exchange interaction in the radical-ion pair (the magnetic-field effect due to HFI-J mechanism). This implies that the magnetic-field effect is unambiguous evidence that Process I (N-oxide→lactam) does not involve the oxaziridine intermediate, but proceeds via the singlet hydrogen-bonded radical-ion pair (radical-ion-pair mechanism of Process I). The irradiation of 1-cyanoisoquinoline N-oxide in ethanol resulted in the formation of 1,3-oxazepine in a ca. 66% yield via the S1 state(Process II). The photochemical isomerization was not affected at all by an external magnetic field. This is consistent with the idea that Process II (N-oxide→oxazepine) does not involve a field-sensitive intermediate, but occurs with the intervention of oxaziridine (the oxaziridine mechanism of Process II).
Rate and Mechanism of Ligand Exchange of Several Tris(β-diketonato)iron(III) Complexes with 4-Isopropyltropolone in Carbon Tetrachloride
Authors: Sekine Tatsuya , Inaba Kazuho 
Published: July 2006

Abstract
The rate of ligand exchange of seven tris(β-diketonato)iron(III) in carbon tetrachloride with 4-isopropyltropolone was measured by a spectrometric method in order to determine the effect of the chemical properties of the leaving ligand on the reaction mechanism. It was found from the dependence of the rate on the leaving and entering ligands and also from the values of ΔH\eweq and ΔS\eweq that the exchange reaction of iron(III) complexes with acetylacetone and its two phenyl-substituted derivatives proceeds by a dissociative mechanism. It was also found that reactions with trifluoroacetylacetone and its phenyl- and 2-thienyl-substituted derivatives proceeds by an associative mechanism. An hexafluoroacetylacetonato complex formed an intermediate with the entering ligand in the first stage of the reaction and then a ligand exchange occured. It was concluded from these results that the ligand exchanges of more stable complexes were controlled by the break of a leaving ligand. Less stable ones were controlled by bond formation with the entering ligand.
Inclusion Complex Formation of γ-Cyclodextrin. One Host-Two Guest Complexation with Water-soluble Dyes in Ground State
Authors: Hirai Hidefumi , Toshima Naoki , Uenoyama Satoshi 
Published: July 2006

Abstract
β-Cyclodextrin forms the 1:1 inclusion complex with Crystal Violet, Methylene Blue, Methyl Orange, or Congo Red in water. On the other hand, γ-cyclodextrin forms the 1:2 complex with Crystal Violet, Methylene Blue, or Methyl Orange, while the 1:1 complex is given with Congo Red. The one host-two guest complexations are shown on the bases of the changes of the electronic spectra, dependence of induced circular dichroisms on the concentrations of dyes, and the continuous variation methods with induced circular dichroism. The dissociation constants for the 1:2 complexes are determined with the improved Benesi-Hildebrand equation. Alternation between the 1:1 and 1:2 complexation is discussed in terms of the cavity size of cyclodextrin and the aggregation character of dye.
Multiple Substituent Effects on 13C Chemical Shifts of N-Benzylideneanilines. Evidence for Substituent–Substituent Interactions and Their Implications of Conformational Changes with Substituents
Authors: Akaba Ryoichi , Sakuragi Hirochika , Tokumaru Katsumi 
Published: July 2006

Abstract
Carbon-13 chemical shifts are reported for series of N-benzylideneanilines; 4-YC6H4CH=NC6H4NMe2-4, 4-NO2C6H4CH=NC6H4X-4, 4-YC6H4CH=NC6H4NO2-4, and 4-YC6H4CH=NC6H3(CH3)2-2,6. Multiple substituent effects on the azomethine carbon chemical shifts were examined, and nonadditivity observed for 4-YC6H4CH=NC6H4NMe2-4 and 4-NO2C6H4CH=NC6H4X-4 is interpreted in terms of substituent–substituent interactions accompanied by conformational changes with substituents in these N-benzylideneanilines. Effects of the substituents Y (on the benzylidene benzene ring) on the azomethine carbon chemical shifts were also studied in detail. The results suggest that there are two competetive electronic factors responsible for chemical shift variation, and that the substituent effects should be treated separately between electron-releasing and electron-withdrawing groups. The latter groups always exert inverse (the chemical shifts undergo upfield shifts with increase in the electron-withdrawing properties of the substituents) substituent effects, whereas the former exhibit normal (the chemical shifts undergo upfield shifts with increase in the electron-releasing properties of the substituents) or inverse substituent effects depending on the degree of electron demand developed on the azomethine carbons.
Synthesis of 3-Amino-5H-pyrido[4,3-b]indoles, Carcinogenic γ-Carbolines
Authors: Akimoto Hiroshi , Kawai Akiyoshi , Nomura Hiroaki 
Published: July 2006

Abstract
The carcinogenic γ-carbolines 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (2) were synthesized efficiently by the following procedures. The key method involved the acid-catalyzed cyclization of 2-acetamido-3-(2-indolyl)alkanoic acids to 1,2-dihydro-γ-carbolines. This was followed by dehydrogenation to the γ-carbolinecarboxylates and conversion of the ester group to the carboxyl and finally to the amino one by Curtius rearrangement. Alternative methods involved the thermolysis of 4-(1-benzotriazolyl)-3,6-dimethyl-2-pyridinamine to synthesize 1 and the condensation of 3-acetylindole-2- acetonitrile with ammonia to synthesize 2. The structures of γ-carbolines 1 and 2 were unambiguously established by comparing samples of each synthesized by the two different routes. A selective and one-step synthesis of ethyl 2-acetamido-3-(2-indolyl)alkanoates was newly exploited starting from diethyl acetamidomalonate and quaternary ammonium salts of 2-[1-(dimethylamino)alkyl]indoles.
A Conductance Study of Benzo-18-crown-6- and Its Analogs-Alkali Metal Ion Complexes in Various Solvents
Authors: Takeda Yasuyuki 
Published: July 2006

Abstract
Limiting ionic molar conductivities of benzo-18-crown-6 (B18C6)–alkali metal ion complexes in various nonaqueous solvents were determined at 25 °C. The mobilities of the B18C6 complexes were compared with those of 18-crown-6 (18C6)– and dibenzo-18-crown-6 (DB18C6)–alkali metal ion complexes. Regardless of varieties of alkali metal ions held in the crown ether cavity, the larger is the size of the crown ether complex, the less mobile the complex is. For aprotic solvents (acetonitrile, DMF, DMSO, propylene carbonate), the mobility of the B18C6–K+ complex is smaller than that of (n-C4H9)4N+; however, for the protic solvent (methanol), they are almost the same. Walden product value of the B18C6–K+ complex as well as 18C6– and DB18C6–K+ complexes somewhat changes with the variation of solvents. For these three crown ether–K+ complexes, Walden product values of acetonitrile and propylene carbonate are larger than or nearly equal to those of DMF and DMSO. This may indicate that, for the aprotic solvents, donicity is a very important factor in determining the magnitude of mobility of the crown ether–K+ complexes. The B18C6–K+ complex as well as 18C6- and DB18C6–K+ complexes seems to act as a structure breaker in a hydrogen-bonding solvent.
The Crystal and Molecular Structure of Tetrakisthiocyanatobis-(triphenylphosphine)cobalt(II)mercury(II) in Dimer Form, [CoHg(SCN)4{(C6H5)3P}2]2
Authors: Kinoshita Hisashi , Shimoi Mamoru , Ouchi Akira 
Published: July 2006

Abstract
The crystal and molecular structure of the title metal complex was determined by the X-ray diffraction method. The crystal is triclinic, with the space group P\bar1, Z=1, a=11.934(2), b=14.642(9), c=11.801(6)Å, α=90.41(5), β=94.04(2), and γ=83.82(2)°. The final R value for 6928 reflections is 0.065. The cobalt(II) ato is in a tetrahedral geometry, ligated by four nitrogen atoms of the thiocyanato (SCN) ligands, while the mercury(II) atom is in a trigonal-bipyramidal geometry, where two phosphorus atoms of both the triphenylphosphine ligands bond axially and three sulfur atoms of SCN’s equatorially; however, these Hg–S bonds are very long. Thus, the pairs of cobalt(II) and mercury(II) atoms are linked by one SCN bridge, forming a sixteen-membered ring of Co2Hg2(SCN)4, and this ring is linked with the next ones on both sides in the a-axis direction with two longer bondings.
Hydrogenation of Carbon Monoxide to Form Light Olefins over an Iron-modified Crystalline Silica
Authors: Sano Tsuneji , Yanagisawa Hiroshi , Okabe Kiyomi , Okado Hideo , Hagiwara Hiroyuki , Yasumoto Yoshiroh , Takaya Haruo 
Published: July 2006

Abstract
Iron-modified crystalline silicas prepared from an Fe(II) compound were more active than those prepared from an Fe(III) compound. The (C2H4+C3H6) selectivity of the former was lower than that of the latter. By the addition of alkaline earth metals, the (C2H4+C3H6) selectivity of the catalysts prepared from the Fe(II) compound increased remarkably.
Change of Orientation in Photoreaction by Oxygen. Effect of Oxygen on Photo-methoxylation of Dimethyl Esters of 2,4- and 3,4-Pyridinedicarboxylic Acid
Authors: Sugiyama Toru , Kanai Mitsuharu , Takenaka Setsuko , Sugimori Akira 
Published: July 2006

Abstract
The UV-irradiation of dimethyl 2,4- and 3,4-pyridinedicarboxylates in methanol in the presence of H2SO4 under O2 brings about methoxylation at the β- position of the pyridine ring, while under N2 methoxylation occurs at the α-position.