bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrazinolysis of Sugar Sulfonates
Authors: Suami Tetsuo , Shoji Tadao 
Published: July 2006

Abstract
Hydrazinolysis of methyl 4,6-di-O-acetyl-2,3-di-O-tosyl-α-d-glucopyranoside (I) or methyl 2,6-di-O-benzoyl-3,4-di-O-mesyl-α-d-glucopyranoside (VI), followed by catalytic hydrogenation and acetylation, afforded methyl 2,4-diacetamido-3,6-di-O-acetyl-2,4-dideoxy-α-d-idopyranoside (II). Also methyl 2,3-di-O-acetyl-4,6-di-O-mesyl-α-d-glucopyranoside (VII) was treated analogously as described above to give methyl 4,6-diacetamido-2,3-di-O-acetyl-4,6-dideoxy-α-d-galactopyranoside (IX). The structures were studied by means of proton magnetic resonance spectra. And a reaction mechanism was also discussed.
Aminocyclitols. XXIII. A Synthetic Study of Streptozotocin Analogs
Authors: Suami Tetsuo , Machinami Tomoya 
Published: July 2006

Abstract
Streptozotocin is an antibiotic which exhibits wide antimicrobial and antitumor activities, and its structure has been established to be N-carbamyl-N′-methyl-N′nitroso-d-glucosamine. In the present article, streptozotocin analogs in which the pyranose ring was substituted for a cyclohexane ring were prepared. These compounds showed considerable activities against Ehrlich ascites tumor.
Aminosugars. XVIII. Synthesis of 3-Acetamido-3,5-dideoxy-d-ribose
Authors: Ando Hiroaki , Yoshimura Juji 
Published: July 2006

Abstract
3-Acetamido-3,5-dideoxy-1,2-O-isopropylidene-α-d-ribofuranose (5) was synthesized through two pass-ways: 1) starting from 3-acetamido-3-deoxy-1,2-O-isopropylidene-α-d-allofuranose which is obtained from d-glucose, through five steps; periodate oxidation, hydrogenation, 5-O-tosylation, 5-iodination and hydrogenation: 2) starting from l,2-O-isopropylidene-3,5-di-O-tosyl-α-d-xylofuranose through four steps; 5-iodination, hydrogenation, 3-amination and N-acetylation. Total yields in the two pass-ways were 12.7% and 7.6% from the parent aldoses, respectively. Hydrolysis of 5 gave the titled compound as a sirup, which was converted to the crystalline osazone. The structure and conformation of intermediates in these syntheses were examined by NMR spectroscopy.
Measurement of Contact Potential Difference for Organic Crystals. Work Function of Violanthrene
Authors: Kotani Masahiro , Akamatu Hideo 
Published: July 2006

Abstract
A vibrating-reed type cell for measuring contact potential difference was constructed and successfully applied for organic crystals. From the observed contact potential difference for violanthrene against graphite, the work function has been estimated as 4.50±0.1 eV. In association with the activation energy for electrical conductivity, 0.8–0.9 eV, the electronic energy diagram for violanthrene has been illustrated, which revealed the extrinsic nature of semiconduction and the energy gap, 2.3–2.5 eV, being comparable with the first excited singlet state of violanthrene molecule.
A Nuclear Magnetic Resonance Study of Copolypeptides of l-Proline with γ-Benzyl-l-glutamate
Authors: Okabayashi Hirofumi , Sakai Rume , Isemura Toshizo 
Published: July 2006

Abstract
The nuclear magnetic resonance spectra of the copolymers of l-proline with γ-benzyl-l-glutamate were measured in tetradeuteroacetic acid, deuterochloroform, a mixed solvent (CD3-COOD : CDCl3=4 : 1), and trifluoroacetic acid. The time dependence of the α-CH resonance peaks of copoly-(3 : 1)-(l-proline, γ-benzyl-l-glutamate) and copoly-(1 : 1)-(l-proline, γ-benzyl-l-glutamate) was observed. The NMR spectra of copoly-(1 : 3)-(l-proline, γ-benzyl-l-glutamate) showed no time dependence which can be ascribed to the conformational change in tetradeuteroacetic acid and the mixed solvent. From these experimental facts we concluded that copoly(3 : 1)-(l-proline, γ-benzyl-l-glutamate) and copoly-(1 : 1)-(l-proline, γ-benzyl-l-glutamate) can assume a poly-l-proline-like helical structure, while copoly-(1 : 3)-(l-proline, γ-benzyl-l-glutamate) can not. Moreover, the ratios of the γ-benzyl-l-glutamate residues which were incorporated into the stable poly-l-proline-II-like helical structure was estimated in copoly-(3 : 1)-(l-proline, γ-benzyl-l-glutamate) and copoly-(1 : 1)-(l-proline, γ-benzyl-l-glutamate).
Studies of Nylon Monolayers, II. Compression Characteristics of the Nylon 8 Monolayer on Water
Authors: Seimiya Toshiko 
Published: July 2006

Abstract
It was reported in the preceding paper that two types of film, A and B, can be distinguished in F-A curves for monolyers of Nylons 6 and 8 on the basis of the difference in behavior in relation to compression and expansion. In the present experiment, the compression and expansion were repeated for the monolayers of Nylon 8 spread from methyl alcohol in order to study the F-A characteristics of these films in detail. It was found that, during the process of first compression, the pressure drops rapidly and the transition of film A to film B occurs beyond a certain degree of compression of the monolayer. The transition was interpreted as the condensation of the monomer residue of the nylon molecule. The equations of the state for the expanded film were found to apply better than Singer’s equation for both types of film, A and B. Further, the effect of the concentrated sulfuric acid solution (3 and 6 n) as a substrate on the F-A curve was examined. There were little difference in the behavior of the monolayers on 3 n sulfuric acid irrespective of the spreading solvent used, but the difference was marked on dilute hydrochloric acid.
Electronic Structures of the Ring-Protonated Aromatic Amines
Authors: Yamaoka Tsuguo 
Published: July 2006

Abstract
In order to study the electronic spectra and stabilities of the ring protonated aromatic amines, π-electron structure of nineteen amino-substituted pentadienyl cations were calculated by the composite molecule method. The lower electronic transitions of these ions are assigned to the charge transfer from amino groups to the pentadienyl cation. Stability of the ground state depends on the extent of intramolecular charge transfer, which is determined by the position and number of amino-substitution. The amino group on 1-, 3- or 5-carbon atom greatly stabilizes the ground state while contribution of the amino group on the other position is quite small. Occurrence of the ring or amino protonation for various amino-substituted benzenes is shown to be well predicted by the calculated stabilization energy.
Studies of the Nylon Monolayer. III. The Interaction between the Nylon Monolayer and Acid Dye
Authors: Seimiya Toshiko 
Published: July 2006

Abstract
The interaction of the monolayers of the Nylons 6 and 8 with the acid dye Orange II was studied by measuring the surface pressure of the nylon monolayers with and without Orange II in the substrate water. No change in the surface tension with the time was observed for the aqueous solution of Orange II in the concentration and pH ranges studied. The interaction between the nylon monolayers (film B) and Orange II was examined by observing the change in the F-A curve of the nylon monolayer due to the addition of Orange II to the substrate and the spreading of the solution. The presence of dye in a spreading solution has little effect, while the pH’s of the both the spreading solution and the substrate exhibit a marked effect on F-A curves. The observed interaction is compared with the behavior of practical dyeing in bulk of the solution.
Scavengeable Electron Yield in the Radiolysis of Liquid and Solid Hydrocarbons
Authors: Kimura Toyoaki , Fueki Kenji , Kuri Zen-ichiro 
Published: July 2006

Abstract
Yields of scavenged electrons have been measured in MCH, 3MP, cumene and tert-butylbenzene at 20°C and −196°C. It has been found that the yield of scavenged electrons is considerably lower at −196°C in the glassy state than at 20°C in the liquid state. The temperature effect on electron scavenging indicates that the difference in the yields of scavenged electrons between the liquid and glassy states is attributed to the variation not of temperature but of the physical conditions of the matrix. We have also investigated the effect of composition in MCH-MTHF mixtures and that of the viscosity of the matrix upon the yield of scavenged electrons at −196°C, which has led us to the assumption that the extent of interactions between thermalized electrons and the matrix would affect the yield of scavenged electrons at −196°C. Since such interactions may be related to the mean free path of electrons, we have calculated the contribution of the electron jump distance to the electron scavenging efficiency. The calculated results appear to explain qualitatively the experimental results.
The Effect of Intramolecular Hydrogen Bonding on the Polarographic Reduction Potentials of Azomethines
Authors: Uehara Miyoshi , Nakaya Jun-ichi 
Published: July 2006

Abstract
The effects of intramolecular hydrogen bonding on the polarographic reduction potentials (E1⁄2) of several azomethines, such as N-salicylidenemethylamine, N,N′-bis(salicylidene)ethylenediamine, N-salicylideneaniline, N-salicylidene-o-aminophenol, and N-benzylidene-o-amino-p-substituted phenols, have been studied in aqueous and non-aqueous solutions. Contrary to expectations, a larger negative shift of E1⁄2 was observed in the case of o-OH-substituted azomethines than in that of unsubstituted azomethines in buffer solutions. On the other hand, the E1⁄2 of the substituted compounds shifted 0.3–0.4V toward the positive side in dimethylformamide or acetonitrile. The relative strengths of hydrogen bonds, as estimated from the positive shifts of E1⁄2, were 6–10 kcal/mol. It has been proposed, from the hydrogen bond strength, the UV spectra, and the p-substituent effects, that the introduction of an o-OH group into the phenylimino ring provides not a periperpendicular conformation, but a coplanar configuration, by means of the formation of the O–H···N hydrogen bond.
The Hydrolysis of the Copper(II) Ion in Heavy Water
Authors: Kakihana Hidetake , Amaya Toshihiko , Maeda Masunobu 
Published: July 2006

Abstract
The hydrolysis equilibria of the copper(II) ion in heavy water have been studied at 25°C by measuring the deuterium-ion concentration by means of a commercial glass electrode. The total copper(II) concentration was varied between 50 and 90 mm, while the concentration of the perchlorate ion was held constant at 3m by the addition of NaClO4. A hydrolyzed copper(II) perchlorate solution was gradually acidified up to the point where hydrolysis was negligible by the use of constant-current coulometry. The experimental data, which indicate a slight hydrolysis in the log d range from –4.0 to –5.26, can be explained by assuming these equilibria;
& Cu^2++D_2O=CuOD^++D^+,logβ_1,1=-7.71±0.07;
& 2Cu^2++2D_2O=Cu_2(OD)_2^2++2D^+,logβ_2,2=-11.46±0.04.
Synthesis of Chelating Agents. VII. Synthesis and Chelating Behavior of 2,3-Dinitrilo-1,2,3,4-tetrahydro-naphthalene-N,N,N′,N′-tetraacetic Acid
Authors: Yano Tairoku , Kobayashi Hiroshi , Ueno Keihei 
Published: July 2006

Abstract
trans,2,3-Dinitrilo-1,2,3,4-tetrahydronaphthalene-N,N,N′,N′-tetraacetic acid was synthesized by the carboxymethylation of trans-2,3-diaminotetrahydronaphthalene. The acid dissociation constants as well as the chelate stability constants for alkaline earth metal ions were determined by a potentiometric method. The results were compared with the values of other complexane ligands of the cycloalkane family.
The Acid-Catalyzed Ring-Opening of Cyclooctenimine Derivatives
Authors: Fujita Shinsaku , Hiyama Tamejiro , Nozaki Hitosi 
Published: July 2006

Abstract
The acid-catalyzed ring-opening of 9-ethoxycarbonyl-9-aza-bicyclo[6.1.0]nonane (1) and-4-nonene (2) is reported to give normal products 3a and 11a, respectively, together with several transannular products.
Structure and Reactivity of α,β-Unsaturated Ethers. X. The Acid-Catalyzed Hydrolysis of Ring-Substituted Styryl Ethyl Ethers
Authors: Okuyama Tadashi , Fueno Takayuki , Furukawa Junji 
Published: July 2006

Abstract
The acid-catalyzed hydrolysis of cis- and trans-styvyl ethyl ethers (SEE) and several of their ring-substituted derivatives has been kinetically investigated in 80% aqueous dioxane. It has been found that these ethers are less reactive than vinyl ethyl ether by a factor of ca. 500 and that all the cis isomers studied are about twice as reactive as the corresponding trans isomers. The hydrolysis of the substituted ethers at 35°C has proved to obey the Hammett relation with the reaction constants ρ=−1.07 and −0.70 for the cis and the trans isomers, respectively. All these results appear to be interpretable at least qualitatively in terms of the reaction scheme involving the rate-determining protonation to the β-carbon atom.
Properties of Vinyl Chlorides-Ethylene Copolymers
Authors: Misono Akira , Uchida Yasuzo , Yamada Kunikazu 
Published: July 2006

Abstract
Properties of vinyl chloride-ethylene copolymers rich in vinyl chloride have been studied by means of infrared as well as NMR spectroscopy and dynamic mechanical testing. The infrared and NMR spectra of the copolymer indicate that crystallinity decreases with decreasing sequence length of the vinyl chloride segment. The copolymer containing more than 80 mol % vinyl chloride shows optical melting point, a plot of which versus logarithmic composition satisfies Flory’s relationship. Temperature dispersion curve of elastic modulus E′ of the copolymer also indicates that the crystalline region of vinyl chloride segments disappears as the ethylene content increases. Glass transition temperature as determined by loss modulus E″ fits Gordon-Taylor’s relationship well provided the coefficient k equals unity.
Alternating Copolymerization of β-Cyanoacrolein with α-Methylstyrene
Authors: Takemura Ichiro , Sumitomo Hiroshi 
Published: July 2006

Abstract
Alternating copolymer was obtained in the system of β-cyanoacrolein (CAL) and α-methyl-styrene (α-MeSt). In the presence of air copolymerization proceeds even without any radical initiator at room temperature. In the radical initiated copolymerization of α-MeSt (M1) and CAL (M2), the values of monomer reactivity ratios r1=0.033 and r2=0 were obtained. Neither the rate of copolymerization nor viscosity number of the copolymer formed were influenced by the presence of air in the reaction system. The result of copolymerization in the ternary system involving methyl acrylate (MA) could not be entirely explained by the copolymerization equation given by Alfrey and Goldfinger for the three component system. It was found that the composition of the copolymer formed changed with the solvent dilution. Formation of 1 : 1 molecular complex between the monomers was evidenced by the application of the continuous variation method to α-MeSt-CAL system. It was concluded that the molecular complex due to some donor-acceptor type interaction between CAL and α-MeSt plays an important role in the copolymerization.
Pyrolysis-Gas Chromatographic Investigation of Chlorinated Polystyrenes
Authors: Tsuge Shin , Ito Hajime , Takeuchi Tsugio 
Published: July 2006

Abstract
The distribution of chlorine atoms in radically chlorinated polystyrenes was studied by means of pyrolysis gas chromatography. Degradation products such as styrene, benzene, toluene and chlorobenzenes are related to different structures of the chlorinated polymers. The sequence distribution of each structure was discussed over a wide range of degree of chlorination. Chlorine atoms are first substituted with α- then β-hydrogen in the main chain of polystyrene. The first ring substitution of chlorine occurs competitively at p-position even before both α- and β-hydrogens are substituted.
The Electron Spin Resonance of the Mn2+ Ion on the Surface of Magnesium Oxide
Authors: Yamamura Takemi , Hasegawa Akinori , Yamada Yoshio , Miura Masaji 
Published: July 2006

Abstract
The behavior of the Mn2+ ion on the surface of MgO was studied by using the ESR technique. The powder of MgO, the surface of which was doped with the Mn2+ ion, was calcined at different temperatures from 100 to 1000°C in a vacuum, and then the ESR spectra were observed at room temperature. It was noticed that the spectral intensity showed a minimum at about 500°C, that the zero-field splitting parameter, D, increased with the temperature, and that the hyperfine coupling constant, A, decreased enormously at about 700°C. The environments around the Mn2+ ion on the surface of MgO were discussed on the basis of these results. When H2, CO, or O2 was added after the calcination, the D and A values changed in the temperature range above 500°C. Especially when O2 was introduced, the D value fell to zero upon treatment at 1000°C. The crystal field around the Mn2+ ion and the bonding between the Mn2+ ion and its environments were discussed by taking into account the results of the magnetic-susceptibility measurements of the manganese ion on MgO.
The Effect of Chloromethanes on Hydrogen Formation in the Radiolysis of Methylcyclohexane and 3-Methylpentane at −196°C
Authors: Kimura Toyoaki , Fukaya Mitsuharu , Hada Minoru , Wakayama Terunobu , Fueki Kenji , Kuri Zen-ichiro 
Published: July 2006

Abstract
The effect of chloromethanes (CH2Cl2, CHCl3 and CCl4) on hydrogen formation from γ-irradiated methylcyclohexane (MCH) and 3-methylpentane (3MP) at −196°C was investigated. It was found that the decrease in hydrogen yield by the presence of CH2Cl2 was almost the same as that caused by an electron scavenger such as N2O, n-butyl chloride, SF6 or iodobenzene, but the hydrogen yield was much lower in the presence of CHCl3 or CCl4 than other electron scavengers. Although the yield of CCl3. radicals formed from dissociative electron attachment to CCl4 in CCl4-MCH systems was ∼1.4G, the decrease in hydrogen yield was ∼3G. A similar result was obtained for CHCl3-MCH systems. Thus we have ascribed the effect of CH2Cl2 on hydrogen formation to electron scavenging and that of CHCl2 or CCl4 to excitation transfer as well as electron scavenging. ESR studies on radical formation from these systems also support the above interpretation.
Catalytic Activity and Reactivity of Aromatic Nitrile and Alkali Metal Ion Radical Salt. I. Homogeneous and Heterogeneous Catalysis of Benzonitrile-Cesium Ion Radical Salt
Authors: Tsuda Motoyuki , Inokuchi Hiroo 
Published: July 2006

Abstract
Homogeneous and heterogeneous mechanisms of parahydrogen conversion and hydrogen-deuterium exchange reactions were investigated in the presence of benzonitrile–cesium ion radical salt. Studies of their activation energies and rate constants showed that the heterogeneous reaction on the solid-ion radical salt occurs mainly through the “chemisorption mechanism” and the “exchange mechanism”, but the homogeneous reaction over the salt solution in benzonitrile takes place only through the “physical mechanism.” According to these results, it was concluded that the catalytic activity and reactivity of the ion-radical salt must be due to the nature of its solid phase, not to that of its aromatic anion or free-ion radical pair.
Determination of Ion Activity Coefficients from the Measurement of Membrane Concentration Potentials–Activity Behavior of Alkali-metal Cations in Aqueous Solutions at 25°C
Authors: Tamamushi Reita , Goto Shojiro 
Published: July 2006

Abstract
The membrane concentration potentials across a permselective sulfonated polystyrene collodion-base membrane were measured with aqueous solutions of alkali-metal salts at 25.0°C. By assuming the ideal behavior of the membrane, the activity coefficients of the critical cations were determined from the membrane concentration potentials at ionic strengths higher than 0.01. The ion activity coefficients of alkali-metal cations were found to follow the order Li+&gt;Na+&gt;K+ for the chlorides, nitrates, perchlorates, and sulfates. The order of activity coefficients of Na+ in different halide solutions was bromide&gt;chloride&gt;fluoride. Considerable differences were observed between the individual and mean activity coefficients at ionic strengths higher than 0.01. The individual ion activity coefficients determined from the experimental data were analysed by means of the extended Debye-Hückel eauation.
Reactive States of Acridine for the Photoreduction in Tetrahydrofuran
Authors: Miyashita Yoshikatsu , Niizuma Shigeya , Kokubun Hiroshi , Koizumi Masao 
Published: July 2006

Abstract
The photoreduction of acridine in tetrahydrofuran (THF) has been investigated by the steady light experiment and also by the flash technique. The quantum yields in the aerated and deaerated solution were 0.12 and 0.36 respectively. The former value is referred to molecular mechanism while the difference of the two, 0.24, to radical mechanism. It was established that the sensitized reaction occurs with biacetyl (T(n–π*), 19700cm−1) as a triplet energy donor. The probability factor β with which the produced T(π–π*) of acridine (15840 cm−1) reacts with THF was found to be \gtrsim0.6. Anthracene T(π–π*), 14700cm−1) was found to act as a triplet energy acceptor and to reduce the photoreduction. From the decrease of the quantum yield caused by the addition of anthracene, the quantum yield via the lowest T(π–π*) of acridine was evaluated as 0.06. By combining this value with the above β-value, the apparent \varphiST has proved to be \lesssim0.1. This very small value compared with the \varphiST values presented for other solvents (benzene\gtrsim0.25, water\gtrsim0.24, ethanol\gtrsim0.29) leads to the conclusion that in THF, T(n–π*) is also a reactive state for the photoreduction. Further, an interesting aspect of the radical mechanism was elucidated from the comparison of ΦR (quantum yield due to radical mechanism) and ΦO2 (quantum yield of oxygen consumption).
The Chemical Behavior of Low Valence Sulfur Compounds. VI. Decomposition of Tetrasulfur Tetranitride in Aqueous Ammonia Solution
Authors: Shieh Mu-Chang , Katabe Kenichi , Okabe Taijiro 
Published: July 2006

Abstract
The decomposition of tetrasulfur tetranitride in an aqueous ammonia solution has been investigated. Ammonolysis of tetrasulfur tetranitride gives thiosulfate, sulfite, sulfate and sulfamate through the intermediate compound of trithionate. An increase in the concentration of ammonia raises the yield of sulfamate and lowers that of sulfate, but gives no remarkable change in the yield of thiosulfate. Besides this, in a concentration of ammonia higher than 15 n at 100°C an explosive reaction takes place. Addition of copper ion improves the yield of sulfamate, and the sulfite ion reacts with tetrasulfur tetranitride in an ammonia aqueous solution to form sulfate and sulfamate ion quantitatively.
Competitive Inhibition of Pepsin by Carboxylic Acids
Authors: Shin Hong Dae 
Published: July 2006

Abstract
In order to obtain evidence for Tang’s hypothesis that pepsin (EC 3.4.4.1) forms a hydrophobic bond with the nonpolar side chain or its substrates, the inhibitory effect of carboxylic acids (from formic acid to isobutyric acid) on the activity of pepsin to the synthetic dipeptide, N-carbobenzoxy-l-glutamyl-l-tyrosine, was studied. Kinetic study showed that the inhibition by carboxylic acids was of competitive type. The inhibitor constant Ki decreased with an increase in the size of the inhibitor molecule. The free energy change of formation of complex between pepsin and hydrocarbon chain of carboxylic acid, −ΔFHc, increased linearly with the increase in the number of carbon atoms in the hydrocarbon chain of the inhibitor. It was suggested that the hydrophobic interaction between the side chain of amino acid residues in the binding region of the active center of pepsin and the hydrocarbon side chain of the inhibitor was the cause of the inhibition.