bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substrate-Nucleophile Association in the Finkelstein Reaction System in Dipolar Aprotic Solvent. Formation of Complex between Substituted Chloromethanes and Halide Ion in Acetonitrile
Authors: Hayami Jun-ichi , Koyanagi Tohru , Hihara Nobuhisa , Kaji Aritsune 
Published: July 2006

Abstract
Substrate-nucleophile association was found between substituted chloromethanes (ArXCH2Cl: X=NONE, S, SO, SO2, and CO) and halide ion (Cl−, Br−, and I−) in dipolar aprotic solvent. The equilibrium constant (K), limiting shift (Δc), the enthalpy of formation (ΔH°), and the entropy of formation (ΔS°), for complexing were determined by NMR measurement. The measurement of spin-lattice relaxation time (T1) gave an information on the conformation of this complex. Halide ion seems to locate closest to α-methylene protons at the site of potential SN2 reaction.
Abnormal Wallach Rearrangement of 4-Alkylazoxybenzenes
Authors: Shimao Ichiro , Matsumura Shigenori 
Published: July 2006

Abstract
The major product in the reaction of 4-alkylazoxybenzenes with sulfuric acid is not 4-(p-alkylphenylazo)phenol, which is regarded as the usual product of Wallach rearrangement. The following azophenols were obtained as major products; 2-alkyl-5-(phenylazo)phenol (R : Me), 2-alkyl-4-(phenylazo)phenol (R : Et), and 4-(phenylazo)phenol (R : i-Pr and t-Bu).
A Synthesis of 2-Substituted 2-Cyclopenten-1-ones
Authors: Ide Junya , Sakai Kiyoshi , Yura Yasuo 
Published: July 2006

Abstract
2-Substituted 2-cyclopenten-1-ones, i.e., 2-(6-methoxycarbonylhexyl)-2-cyclopentene-1-on and 2-butyl-2-cyclopenten-1-one were synthesized by cyclization of the corresponding 4-oxo-1-pentanals, which were obtained from 3-substituted 1,1-dimethoxy-2,4-pentadiones through several steps.
MO Calculations of the Rydberg Transitions of the Methane Molecule
Authors: Kohda-Sudoh Susumu , Katagiri Shigeyoshi 
Published: July 2006

Abstract
The vertical transition energies of both the Rydberg and valence-shell type transitions of CH4 were calculated by the use of the ab initio SC-LCAO-MO method. We used Slater-type AO’s as the basis AO’s and added the extra-valence AO’s (3s, 3p, 4s, and 4p) of a carbon atom to the minimal-basis set in order to express the Rydberg MO’s. From the limited CI calculations, the mixing expressed in terms of the orthogonalized AO’s between the Rydberg and valence-shell transitions was shown to be little. The lowest two absorption bands near 9.7 and 11.7 eV were identified as a 3s-like Rydberg transition with a 3p-like one and a 4s-like Rydberg transition with a 4p-like one respectively. The total energy and Mulliken population analysis were also calculated and compared with the results of the minimal-basis calculations.
Reaction of Hydrogen Atoms with Acrylaldehyde
Authors: Koda Seiichiro , Nakamura Kazumoto , Hoshino Takashi , Hikita Tsutomu 
Published: July 2006

Abstract
The reaction of hydrogen atoms with acrylaldehyde was investigated in a fast flow reactor equipped with a time-of-flight type mass spectrometer under reduced pressure. Main reaction products were carbon monoxide, ethylene, ethane, methane, and propanal. Consideration of the distributions of the reaction products under various reaction conditions showed that hydrogen atoms attacked the C=C double bond, especially its inner carbon side under reduced pressure. Resulting hot radicals caused subsequent reactions. The relative value of the apparent bimolecular rate constant of the reaction against that of trans-2-butene with hydrogen atoms was 1.6±0.2, which supported the above-mentioned initial reaction.
Polarized Electronic Absorption Spectra and Assignment of Fluorene and Biphenyls
Authors: Yoshinaga Tetsutaro , Hiratsuka Hiroshi , Tanizaki Yoshie 
Published: July 2006

Abstract
The divided electronic spectra polarized parallel to the long and short axes of molecules of biphenyl, THP (4,5,9,10-tetrahydropyrene), fluorene, and DHPH (9,10-dihydrophenanthrene) were determined by dichroism analysis using the stretched PVA film method. The experimental results are in good agreement with the ones calculated by the LCAO MO SCF CI method. Every compound has a very weak absorption (f≈10−4) as the first band in the region of 32000–35000 cm−1, which is electronically allowed and polarized parallel to the short axis. The intense band (34000–44000 cm−1) of biphenyl consists of a relatively strong (39100 cm−1) band and a weak (40500 cm−1) band: the former is polarized parallel to the long axis and the latter to the short. Both fluorene and DHPH show five well corresponding electronic bands in the region below 45000 cm−1.
A Molecular Orbital Study on the Partial Reactivity of Hydrogen of Various Amino Acids in the Abstraction Reaction by Hydroxyl Radical
Authors: Shinohara Hiroyuki , Imamura Akira , Masuda Takahiro , Kondo Masaharu 
Published: July 2006

Abstract
The reactivities of hydrogen atoms of aliphatic amino acids toward hydroxyl radicals in the hydrogen atom abstraction reaction have been studied in terms of the energy required for stretching the C–H bond which is attacked. The energy required for stretching the C–H bond by 0.5 Å from the equilibrium bond length has been calculated by the INDO method and compared with the partial rate constants experimentally assigned to the hydrogen atoms of aliphatic amino acids. The energy required has been correlated only with the partial rate constants of the hydrogen atoms on the β-carbon atom. For the hydrogen atoms on the α-carbon atom, although data was insufficient a similar situation has been observed. The reactivities of the hydrogen atoms on the γ and δ-carbon atom failed to correlate with the stretching energy. The reasons are discussed in terms of the effect raised by the configuration of amino acid molecules in solution. The stretching energy has also been found to be consistent with the electrophilicity observed in the hydrogen abstraction reaction by hydroxyl radical.
Thermodynamics of the Redox Equilibria and the Site Preference in(Fe1−yAly)3−δO4
Authors: Nakamura Akio , Yamauchi Shigeru , Fueki Kazuo , Mukaibo Takashi 
Published: July 2006

Abstract
In order to elucidate the defect model in the spinel ferrites, the nonstoichiometry in magnetite and its solid solutions, (Fe1−yAly)3−δO4, (y=0.0, 0.25, 0.33), was determined at temperatures between 1300 and 1550 °C. The redox equilibria between Fe2+ and Fe3+ and the site preference of Fe2+, Fe3+, and Al3+ ions and cation vacancies were investigated and sixteen kinds of models were examined. The “best” model was chosen using the criteria that the dependence of the equilibrium constant on δ and y should be as small as possible. In the selected model, Fe2+ ions on B-sites are regarded as electron donors in a narrow 3-d band formed by Fe ions in B-sites. The following expression for the defect equilibrium was found:
\frac23(1−y)FeA2++\frac2(2−3y)3(1−y)eB−+\frac12O2(g)\ightleftarrows\frac23(1−y)FeA3++\frac14VA+\frac12VB+OL2−.
The Chemistry of Americium. IV. The Stability of Am(V) and Am(VI) in Nitric Acid Solutions and in the Solutions Containing Ozone Gas Fluoride, or Phosphate Ions
Authors: Hara Mitsuo , Suzuki Shin 
Published: July 2006

Abstract
The coprecipitation technique with BiPO4 and ThF4 was applied to studying the stability of Am(V) and Am(VI) at concentrations lower than 10−6 M. It was found that 241Am(V) and 241Am(VI) were rapidly reduced to 241Am(III) in nitric acid solutions at low acidities and at high temperatures, but the reduction was effectively inhibited by the presence of ozone gas or fluoride ions. On the other hand, 243Am(V) and 243Am(VI) were found to be rather stable in nitric acid solutions, while they were readily reduced to 243Am(III) in phosphate solutions in the same manner as 241Am(V) and 241Am(VI).
Color Reactions of Aqua(ethylenediaminetetraacetato)ruthenate(III) with Sulfur Compounds. Kinetic Study of Thiosulfate Anation
Authors: Yoshino Yukichi , Uehiro Takashi , Saito Masami 
Published: July 2006

Abstract
New color reactions of aqua(ethylenediaminetetraacetato)ruthenate(III) with sulfur compounds such as thiols, thiourea and thiosulfate have been found and investigated. It has been established that the coloration is due to the anation of the complex with sulfur compounds. In the case of thiosulfate, the reaction is first order in either reactant and independent of [H+] in the pH range 4 to 6. The rate constant (kAN) was found to be 2.94±0.11 M−1 s−1 at 30 °C and I=0.1. For a pH&gt;6, the rate decreases with increase in pH due to the formation of a hydroxo complex. In the higher pH region, the reverse reaction, [Ru(edta) (S2O3)]3−+OH−\ightleftarrows[Ru(edta) (OH)]2−+S2O32− takes place. From the value of the equilibrium constant (Keq) for this reaction, the equilibrium constant (KAN) for thiosulfate anation has been estimated as, logKAN=5.02 at 30 °C and I=0.1.
Synthesis of Methyl Substituted Chromanol. An Analogue of Vitamin K
Authors: Maruyama Kazuhiro , Tobimatsu Takamasa , Naruta Yoshinori 
Published: July 2006

Abstract
Methylation of 2,2-dimethyl-3,4-dihydro-2H-benzo[h]chromen-6-ol (1) is examined to yield 2,2,3-trimethyl-3,4-dihidro-2H-benzo[h]chromen-6-ol (2). The compound 2 is prepared by Mannich reaction followed by hydrogenative cleavage of the Mannich bases, which are obtained in the reaction with three kinds of amine. Chloromethylation of 1 quantitatively gave a dimer of naphthoquinone methide.
Studies of Polymeric Flocculants. IX. The Formation of Poly(methacrylohydrazide)–Copper(II) Complexes
Authors: Nonaka Takamasa , Momono Eiji , Egawa Hiroaki 
Published: July 2006

Abstract
Formation constants for the complexes of poly(methacrylohydrazide) (PMH) with the copper(II) ion were measured by using a modification of Bjerrum’s method proposed by Gregor and his coworkers. The pKa1 and pKa2 values of PMH determined in an aqueous solution with an ionic strength of 0.1 (KNO3) at 25 °C were 3.20 and 10.61 respectively. Therefore, when the PMH-copper(II) complexes were formed above pH 7, the average number of ligands combined with one metal ion could be calculated approximately without using the first acid dissociation constant. The pKa2 value decreased with an increase in the ionic strength and temperature. The formation curves of the complexes showed that one copper(II) ion formed a coordination compound with six hydrazide groups in a high pH region (about pH 9). The formation constants increased with an increase in TCu/THL (the ratio of the total concentration of the copper(II) ion to the total concentration of the ligand) in the range higher than 0.1. The formation constants were unaffected by the degree of polymerization of PMH in the range from 64.1 to 5470, but the formation constants were affected by the kind of anion in copper(II) salts and neutral salts added and they increased in the order of NO3−&lt;SO42−&lt;Cl−. The thermodynamic parameters for the above reaction were determined by Ringbom’s method.
The Conformation and the Ring Inversion of 8,9,10,11-Tetrahydro-7H-cycloocta[de]naphthalene
Authors: Kamada Toshihiro , Yamamoto Osamu 
Published: July 2006

Abstract
The 1H-NMR spectra of 8,9,10,11-tetrahydro-7H-cycloocta[de]naphthalene (1) and its 8,8,10,10-tetradeuterio derivative have been studied at various temperatures. The NMR parameters of compound 1 were determined accurately by means of computer analysis of the low-temperature spectrum. It was found that the ground-state conformation of 1 is a boat, which is somewhat in a distorted form (puckering) as a result of the steric repulsion between the interior benzyl protons. Activation parameters ΔG\eweq, ΔH\eweq, and ΔS\eweq for the boat inversion process in the molecule were obtained by the line-shape analysis method as 14.5, 16.1 kcal/mol and 5.4 e.u., respectively. These results are best explained in terms of a conformational interconversion process in which the pseudorotations of the peri bonds are involved. Some discussion is also made on the conformational properties of compound 1 in comparison with those of the structurally analogous benzocyclic compound 6,7,8,9-tetrahydro-5H-benzocycloheptene.
The Acid-catalyzed Reactions of 4-Chromanones with Formaldehyde
Authors: Ninagawa Akira , Nomura Ryoki , Matsuda Haruo 
Published: July 2006

Abstract
The reactions of several methyl substituted 4-chromanones, such as 4-chromanone (1a), 6-(1b), and 8-methyl-(1c), as well as 5,7-(1d) and 6,8-dimethyl-4-chromanone(1e) with formaldehyde were carried out in dioxane or mixed solutions of acetic acid and benzene or cyclohexane in the presence of sulfuric acid as a catalyst. The reactions involved an aldol condensation analogous to the Prins reaction, affording acetoxymethyl derivatives and 1,3-dioxanes. It was found that the formation of products was strongly influenced by the substituents on the 4-chromanones and solvents. In a mixed solution of acetic acid and benzene, 1b and 1e gave acetoxymethyl derivatives and 1,3-dioxanes, 1a and 1c only 1,3-dioxanes, and 1d a resinous substance. In a dioxane solution, 1b and 1e gave 1,3-dioxanes, while 1c gave a polymer. Bromination of 1e in 35 and 96% sulfuric acids gave 3- and 5-bromo-6,8-dimethyl-4-chromanones, respectively. The acid-catalyzed reactions were compared with those in 96% sulfuric acid on the basis of the duterium exchange rates of 4-chromanones.
Preparation of N-Acetylmuramyl-l-[U-14C]alanyl-d-isoglutamine via a Novel Synthetic Route
Authors: Kusumoto Shoichi , Ikenaka Kazuhiro , Shiba Tetsuo 
Published: July 2006

Abstract
For the investigation on the action mechanism of immunoadjuvant active N-acetylmuramyl-l-alanyl-d-isoglutamine, its labeled compound, i.e., N-acetylmuramyl-l-[U-14C]alanyl-d-isoglutamine was synthesized. For this purpose, an entirely novel synthetic route for the muramyl dipeptide was exploited using cold materials and applied to the preparation of the labeled compound. A convenient synthetic procedure of isoglutamine derivatives is also described.
Synthesis of Some Naturally Occurring Acetylchromenes
Authors: Chand Jain Amolak , Khazanchi Rajesh , Kumar Ashwani 
Published: July 2006

Abstract
2,4-Dihydroxy-5-methoxyacetophenone on treatment with 3-chloro-3-methyl-1-butyne in the presence of K2CO3, KI, and DMF yielded its 4-(1,1-dimethyl-2-propynyl) ether (2) and the naturally occurring 6-acetyl-5-hydroxy-8-methoxy-2,2-dimethylchromene (3). More of the chromene (3) could be obtained by the thermal cyclisation of the acetophenone (2). Methylation of 3 yielded another natural chromene. 4-Hydroxy-3-methoxyacetophenone, on similar treatment with 3-chloro-3-methyl-1-butyne, gave directly natural 6-acetyl-8-methoxy-2,2-dimethylchromene. 2,3,4-Trihydroxy-5-(3-methyl-2-butenyl)acetophenone, on cyclodehydrogenation followed by methylation with 1 mol of dimethyl sulfate, yielded natural ripariochromene-A. Further methylation provided methylripariochromene-A.
Design and Performance of the Air–Propane Nebulizer Burner for Atomic Absorption Spectrometry
Authors: Tsujino Ryuzo , Ogawa Akira , Musha Soichro 
Published: July 2006

Abstract
A new air–propane nebulizer burner, by the use of which the sensitivity and precision for atomic absorption measurements was approximately equal to those with an air–hydrogen nebulizer burner, has been developed. The flame with this burner has other characteristic features, such as low auditory noise, high stability, and low radiation noise in the OH band.
Dissolution of Metallic Copper in Ethylenediaminetetraacetate Solution in the Presence of Hydrogen Peroxide
Authors: Ohzeki Kunio , Takeuchi Koji , Kambara Tomihito 
Published: July 2006

Abstract
A 50 mg portion of metallic copper (100 mesh) placed in 50 ml of a neutral solution containing 0.1 mol dm−3 ethylenediaminetetraacetate (EDTA) was quantitatively dissolved within 20 min at 50 °C after the addition of a small amount of hydrogen peroxide, resulting in blue coloration of the copper(II)–edta complex.
Study of Metal–Polycarboxylate Complexes Employing Ion-selective Electrodes. III. Complex Formation between Maleic Acid Copolymers and Bivalent Transition Metal Ions
Authors: Yamashita Fumitaka , Komatsu Tsuyoshi , Nakagawa Tsurutaro 
Published: July 2006

Abstract
The complex formation of bivalent transition metal ions, Mn(II), Co(II), Ni(II), Cu(II), and Zn(II), with copoly(maleic acid–ethylene) and copoly (maleic acid-styrene) in aqueous solution was studied by potentiometric titration at 25 °C and the ionic strength of 0.1. The systems containing copper(II) ions were investigated by potentiometry employing the copper(II) ion-selective electrode. The titration curves of the bivalent metal–copoly(maleic acid–ethylene) systems were situated in a lower pH region than in the absence of the metal ions. The complex formed involves two carboxylate groups: primary and secondary. The equilibrium constant of the copper(II) complex was estimated to be 10−2.6. In copoly (maleic acid–styrene) systems, however, the titration curves in the absence and presence of bivalent metal ions overlapped partly in the first neutralization step. From the potentiometric results employing the ion-selective electrode, it was observed that the concentrations of copper(II) ions decrease slightly in the region of overlap. This anomalous behavior is due to the acid dissociation influenced by the conformational transition, including the effect of the side groups of the polymers.
Perturbation Calculation of Spin Densities in π-Electron Radicals
Authors: Hamano Hidekazu , Kondo Hiroshi 
Published: July 2006

Abstract
The unrestricted Hartree-Fock perturbation technique was applied to the calculation of spin densities in many hydrocarbon radicals. The method is similar to that of McLachlan but contains partly the SCF and projection procedures. The results agree with the more rigorous SCF ones.
Solubilities and Rates of Dissolution of Diaspore in NaOH Aqueous Solutions
Authors: Chang Byong-Tae , Pak Li-Hye , Li Yu-Suk 
Published: July 2006

Abstract
The solubility of diaspore (α-Al2O3·H2O or α-AlOOH) has been measured in NaOH aqueous solutions from 523.15 K to 598.15 K, and at concentrations of Na2O up to 150.7 g/l. In order to evaluate the equilibrium constant, K2°=(aAlO2−·aH2O)⁄aOH−, for the dissolution equilibrium of diaspore AlOOH(s)+OH−(l)=AlO2(l)+H2O(l), two methods have been applied to the solubility data. In the first method, analogous to the method previously applied to the dissolution equilibria of gibbsite, bayerite and beohmite, the values of K2 at relatively low concentrations of NaOH were extrapolated to zero NaOH concentrations. The temperature dependence of K2° was expressed as logK2°=−(2500⁄T)+4.45. The second method was based on the extended Debye-Hückel theory for the variation in the activity coefficients of AlO2−, OH−, and H+ ions with ionic strength at any temperature, that is, the value of the solubility product, K1°=aH+·aAlO2−, was obtained at a given temperature by extrapolating values of K1 equal to (mH+mAlO2−), to zero ionic strength. According to the second method, K2° was expressed as a function of the temperature: logK2°=−(1600⁄T)+2.52 when A=2.0 or logK2°=−(1550⁄T)+2.48 when A=1.5, where A is a parameter. From kinetic analysis of the dissolution rate of diaspore in NaOH solution, the rate constants per unit surface area of diaspore were found to be 0.31, 0.45, and 0.68 m−2 h−1 at 548.15, 573.15, and 598.15 K, respectively.
Polymer Effects under Pressure. III. Hydrolysis of Normal Alkyl Acetate Catalyzed by Dodecyl Hydrogensulfate Micelle
Authors: Taniguchi Yoshihiro , Inoue Osamu , Suzuki Keizo 
Published: July 2006

Abstract
Measurements of the rates of hydrolysis of methyl, ethyl, propyl, and butyl acetates have been made to 2 kbar in water catalyzed by dodecyl hydrogensulfate (DSA) micelle at 40 °C. The rate of hydrolysis decreases with compression up to approximately 1 kbar and then increases above 1 kbar; methyl acetate differs in these respects. The inversion phenomenon under pressure has been explained by the incorporation of both the H3O+ ion and ester molecules into the micellar phase. The observed value of the over all activation volume at 1 atm ΔV* is −5.3±1 cm3/mol for methyl, 0.40±1 cm3/mol for ethyl, 9.7±1 cm3/mol for propyl, and 20±1 cm3/mol for butyl acetate, respectively. From the activation volumes of HCl and DSA micellar catalysts, the volume change accompanying the incorporation of the esters into the micellar phase ΔΔVmicelle, has been estimated to be 4.0±1 cm3/mol for methyl, 9.8±1 cm3/mol for ethyl, 18.7±1 cm3/mol for propyl, and 27.9±1 cm3/mol for butyl acetate, respectively. The values above have been explained in terms of the contribution to the hydrophobic interaction between the ester molecule and the micelle.
Deuteration Kinetics of Tyrosine by Means of Fluorescence Measurement
Authors: Nakanishi Mamoru , Tsuboi Masamichi 
Published: July 2006

Abstract
When tyrosine was rapidly transferred from water into deuterium oxide medium by means of a stopped-flow device, a time-dependent change in the fluorescence intensity at 305 nm (excited at 275 nm) has been observed. The rate constant (ke) was found to be 116 s−1 at pH 5.8 and 14 °C. This ke value has been attributed to the rate constant of the O1H→O2H reaction of the phenolic OH group, on the basis of similar fluorescence examinations on phenol, anisole, glycyl-l-tyrosine, and Nα-acetyl-N-methyl-l-tyrosinamide as well as on the basis of a stopped-flow ultraviolet absorption study of tyrosine. The stopped-flow fluorometry has been applied to a study of tyrosine residues in yeast 3-phosphoglycerate kinase.
On the Normal Modes of Vibration in the Uracil Residue—The Use of 15N-Isotope Effects
Authors: Nishimura Yoshifumi , Haruyama Hideyuki , Nomura Kimiko , Hirakawa Akiko Y , Tsuboi Masamichi 
Published: July 2006

Abstract
β-Uridine-5′-phosphoric acid-15N2 has been prepared from 15N-RNA of baker’s yeast which was grown in (15NH4)2SO4 as the sole nitrogen source. Its Raman spectrum has been observed both in 1H2O and 2H2O solutions. On the basis of the observed 15N isotope effects on the Raman spectra and on the basis of other data previously obtained, normal modes of vibration have been discussed for six Raman bands of the uracil residue that are considered to be in resonance with its electronic transition at 260 nm. The result has led to a conclusion that C5=C6 is longer and C4–C5 is shorter in the excited electronic state Ã (260 nm) than those in the ground electronic state \~{X}.
Studies of Inorganic Ion Exchangers. IV. Ion Exchange Equilibrium between Titanium(IV) Bis(hydrogenphosphate) and NaCl–KCl Aqueous Solution
Authors: Kobayashi Etsuro 
Published: July 2006

Abstract
In order to develop an inorganic ion exchanger, ion exchange equilibriums between titanium(IV) bis(hydrogenphosphate) and NaCl–KCl aqueous solution have been investigated together with the possibility of separation of Na and K ions. A suitable quantity of Ti(HPO4)2·H2O (monohydrate), or Ti(HPO4)2 (anhydrate) was added to a fixed volume of the mixed solution of 0.1 M NaCl with 0.1 M KCl at various ratios. The Na and K ions in the equilibrium solution were determined, and the mole fractions of the ions distributed in the liquid and solid phases estimated. When 0.1 or 0.5 g of the monohydrate were added to 10 ml of each initial solution, the sum of the ion exchange capacities for Na and K ions was approx. 0.1–0.3 meq/g. When 0.1 g of the anhydrate were added to 10 ml of each of the initial solutions, the pH of the final solutions showed values in the range of 1.6–1.9. With the mole fractions of KCl/(NaCl+KCl) above 0.5 in the initial solution, only 2.5–3.5 meq/g of the K ion adsorbed. With an excess (0.5 g exchanger to 10 ml soln) of the anhydrate, all K ions and a part of Na ions were removed together from the solution with the mole fractions of KCl/(NaCl+KCl) being in a range of 0–0.8. The K ion could be effectively separated, when a suitable amount of the anhydrate was added to a solution containing approx. an equimole of NaCl and KCl; however, the elution of K ion with HCl could not be eased by this static method.