bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Reaction of Methyl 2-Dimethoxymethyl-3-methoxypropionate with Amidines
Authors: Nishino Takenori , Miichi Yoshiyuki , Tokuyama Kanji 
Published: July 2006

Abstract
The reaction of methyl 2-dialkoxymethyl-3-methoxypropionate with acetamidine has been reported to afford 2-methyl-4-hydroxy-5-methoxymethylpyriniidine (13a) by a different mode than the reaction of 2-dimethoxy-methyl-3-methoxypropionitrile (1), which affords dihydropyrimidopyrimidine (4). As the presence of this difference seemed to be somewhat curious from the viewpoint of the reaction mechanism, the reaction of methyl 2-dimethoxymethyl-3-methoxypropionate (7) with acetamidine was reinvestigated. The reaction products were 13a and acetamidinomethylpyrimidine (17a). Similar results were obtained by the reaction of 7 with benzamidine. As the compound 17 corresponds to 4, the reaction of 7 was concluded to proceed in a manner similar to that of 1; that is, no essential difference exists between the reactions of 1 and 7 with amidines.
The Structure of Shikokianidin, a Minor Component of Isodon shikokianus Hara
Authors: Isobe Takahiko , Kamikawa Tadao , Kubo Isao , Kubota Takashi 
Published: July 2006

Abstract
Shikokianidin from Isodon shikokianus Hara is formulated as structure (3) on the basis of chemical and spectroscopic evidence.
Studies on Amino-hexoses. XVII. Identification of the Deamination Products from d-Glucosaminitol
Authors: Bando Tomoyuki , Matsushima Yoshio 
Published: July 2006

Abstract
The nitrous deamination products of d-glucosaminitol were fractionated with a Dowex-1 free base column after the reaction mixture had been reduced with sodium borohydride. The chromatography gave discrete five peaks, four of which were identified as 2-deoxy-d-arabino-hexitol, 2-deoxy-d-ribo-hexitol, 2-hydroxymethyl-2-deoxy-d-arabino(or ribo)-pentitol and d-mannitol in a total yield over 90%. The nitrous deamination products fractionated with a Dowex-1 borate column were identified as 2-deoxy-d-arabino-hexose, 2-deoxy-d-erythro-3-hexulose, 2-hydroxymethyl-2-deoxy-d-arabino(or ribo)-pentose and d-mannitol. The formation of products other than d-mannitol was interpreted in terms of intramolecular rearrangement accompanying nitrous deamination.
The Photo-induced Addition of Acetic Acid to Cyclohexene Derivatives
Authors: Leong Ta-Yan , Imagawa Takeshi , Kimoto Koichi , Kawanisi Mituyosi 
Published: July 2006

Abstract
The irradiation of methyl 3-cyclohexene-1-carboxylate in acetic acid in the presence of benzene as a sensitizer yields methyl trans-4-acetoxycyclohexanecarboxylate predominantly, together with a small amount of methyl trans-3-acetoxycyclohexane-1-carboxylate; the corresponding cis-isomers are not detected. Under the same conditions, on the irradiation of dimethyl esters of cis- and trans-4-cyclohexene-1,2-dicarboxylic acids, the two possible isomers of acetic-acid adducts with respect to each starting substance are obtained. The irradiation of trans-8-oxabicyclo[4.3.0]non-3-ene gives the two possible acetic-acid adducts, whereas in the case of the irradiation of the cis-isomer, only two equatorially-substituted acetic-acid adducts are obtained. The structural elucidation and the mechanism of the formation of these compounds are discussed.
Electron Spin Resonance Study on Photoinduced Changes of the Radicals Produced in Methyl Isocyanate Solid Irradiated with γ-Rays
Authors: Fujiwara Masato , Tamura Naoyuki , Hirai Hidefumi 
Published: July 2006

Abstract
Free radicals in the γ-irradiated solid of methyl isocyanate at −196°C have been studied by electron spin resonance (ESR) at −196∼−100°C. An oriented solid of methyl isocyanate was prepared by solidification of methyl isocyanate around an aluminum rod under cooling. The original radical and trapped electron produced by γ-irradiation were recorded at −196°C in the dark. The original radical produced in the oriented solid gave a resonance pattern consisting of a triplet of triplets and was assigned to ·CH2NCO radical. This was converted completely into a new radical on irradiation with visible light for 90 min. The new resonance pattern consists of a triplet of triplets whose nitrogen and proton splitting constants are 20.0 and 87.4 gauss, respectively. The nitrogen hyperfine splitting was anisotropic and the proton splitting constant agreed with that of methylene imino radical (H2C=N·). The new radical was assigned to methylene imino radical. The resonance pattern of ·CH2-NCO radical was restored when the temperature was raised up to −120°C. The mutual conversion between the two radicals by visible light and heat was concluded to be a decomposition of ·CH2NCO into H2C=N· and CO, and a recombination of these two moieties.
Automatic Recording of Liquid Penetration through Filter Paper and Wetting Behavior of Liquids
Authors: Nakamura Akio , Seimiya Tsutomu , Sasaki Tsunetaka 
Published: July 2006

Abstract
The penetration of liquid through a vertically suspended filter paper was studied by measuring the weight increase with a strain gauge tensiometer for several organic liquids and aqueous solutions. The plot of penetration rate K=h⁄t1⁄2 (h, height of liquid rise and t, time) against (σ⁄η)1⁄2 (σ, surface tension and η, viscosity coefficient of wetting liquids) showed two straight lines, one for organic liquids and the other for aqueous solutions of sodium dodecyl sulfate. Both these lines passed the origin, suggesting Lucas-Washburn formula to hold. The plots for ethyl alcohol-water mixtures showed behaviors intermediate between those two linear relations. The aqueous solutions caused swelling of fibers and reduced the mean capillary radius of the filter paper, resulting in a decrease of the penetration constant P=K⁄(σ⁄η)1⁄2 but with a rather large K value. The plots for penetration of water through an untreated paper fell far below the straight line obtained for aqueous solutions of sodium dodecyl sulfate. The penetration was recovered by removing fatty contaminants from the filter paper using Soxhlet extractor with ether. The results of a simple test of unfolding a folded paper by touching it with liquids are also in line with those mentioned above.
The Effects of Ion-pair Formation on the ESR Spectra of the Anion Radicals of 4-Nitropyridine N-Oxide and 4-Nitropyridine
Authors: Kawamura (née \={O}ishi) Yoshiko , Nishikida Koichi , Kubota Tanekazu 
Published: July 2006

Abstract
The effect of potassium ion-pair formation on the ESR spectra of the anion radicals of 4-nitropyridine and its N-oxide (4NPO) was studied at various temperatures lower than room temperature. The hyperfine splitting constant values due to hydrogen, nitrogen, and potassium nuclei were determined by applying the simulation technique. The above value arising from the potassium nucleus, decreased with a decrease in the temperature. Molecular orbital calculations covering the whole system of the 4NPO−–M+ ion pair and employing the McLachlan modification for the spin-density calculation were carried out in order to discuss the configuration of the ion pairs and the temperature dependence of the hyperfine coupling constants. It was reasonably concluded that an alkali metal cation occupies the C2 axis of the anion radicals and is in contact with the nitro-group oxygen atoms (the symmetry of the ion pairs is C2v.). The temperature dependence of the hyperfine splitting constants was explained using the vibrational model of Atherton and Weissman.
Interaction between Excited β-Naphthol and Pyridine. Hydrogenbond Formation in S* and H-Transfer Reaction in T
Authors: Kikuchi Koichi , Watarai Hitoshi , Koizumi Masao 
Published: July 2006

Abstract
The interaction between the excited β-naphthol and pyridine in cyclohexane has been investigated by an absorption-emission flash technique. The triplet naphthol has been found to be deactivated by pyridine with the rate constant of 1.5–1.9×109 M−1sec−1, yielding naphthoxyl radical. With 10−4 M pyridine the triplet naphthol is completely transformed into naphthoxyl radical. Above 10−1 M pyridine naphthol exists almost exclusively as a H-bonded species in the ground state, which is non-fluorescent and produces no transient species detectable by an ordinary flash apparatus. For 10−4–10−1 M pyridine, the singlet excited naphthol undergoes collisional deactivation which most likely leads to a H-bonded species (rate constant, 1.2–1.4×1010 M−1sec−1). At the same time naphthoxyl radical is also produced with about the same rate constant as that for the triplet state. The results strongly suggest that the mechanism for the internal conversion of the singlet excited state via H-bonding is a transient H-atom transfer.
The Enthalpies of Binary Mixtures of Chalcogen Elements
Authors: Maekawa Takashi , Yokokawa Toshio , Niwa Kichizo 
Published: July 2006

Abstract
The enthalpies of binary mixtures among chalcogen elements were measured by means of calorimetry. In the system of sulfur+selenium, the positive enthalpy increment suggests the formation of a co-ring and a co-chain on mixing. In the selenium+tellurium and sulfur+tellurium systems, some local ordered structures were deduced from the minimum points of the enthalpy at the compositions of Te3Se2 and Te3S. In the latter system, the entropy of mixing was calculated from the reported phase diagram and the present enthalpy values. The entropy diagram also suggests that the local order is present.
The Reflection Spectra of Würster’s Salts
Authors: Oohashi Yukako , Sakata Tadayoshi 
Published: July 2006

Abstract
The reflections of N,N-dimethyl-p-phenylenediamine (WR) perchlorate, bromide, and iodide, and also of p-phenylenediamine (PD) perchlorate and bromide were measured over the range from 5000 to 42000 cm−1 by Avery’s method. The absolute absorption intensity and the refractive index of these solids were obtained by computer analysis. The absorption intensity of the solid was found to be, as a whole, larger than that of the dimer in solution; in particular, the CT band becomes broader and splits in a solid. Further, the anion was found to have a large effect on the electronic structure in the crystal. By taking account of these features of the spectrum and other experimental results, the WR salts were classified into two types according to their way of packing: Type I takes the dimer-unit structure (WRP) and Type II, the equidistantly-overlapped form (WRB and WRI).
The Preparation and Crystal Structure of Ternary Rare Earth Borides, RCo3B2
Authors: Niihara Koichi , Yajima Seishi 
Published: July 2006

Abstract
In the ternary system of rare earth-cobalt-boron, RCo3B2 compounds (R=rare earth elements) were prepared by arc-melting methods. Their crystal structure was investigated by X-ray diffraction methods. These ternary borides, RCo3B2, crystallize in a hexagonal lattice. The lattice parameters are a=5.020±0.002 Å and c=3.027±0.002 Å for YCo3B2 and a=5.066±0.003 Å and c=3.022±0.002 Å for GdCo3B2. The good agreement between the X-ray diffraction intensities observed and calculated shows that the ternary borides, YCo3B2 and GdCo3B2, crystallize in the CaZn5-type structure. The space group and atomic positions are as follows: P6/mmm (D6h1), 1R in 1(a), 3Co in 3(g), and 2B in 2(c). It can be seen from these results that the ternary borides, RCo3B2, have a superstructure in which two Co atoms in the 2(c) site of intermetallic compounds, RCo5, with the CaZn5-type structure are replaced by two B atoms. The B atoms in this structure are situated at the center of a trigonal prism formed by six Co atoms. The interatomic distances between B and the six Co atoms are 2.11–2.10 Å and are fairly constant, although the radii of the rare earth atoms are changed according to the lanthanide con-traction. We have also found RCo3B2 compounds to be isostructural with YCo3B2 and GdCo3B2, where R=Ce, Sm, Tb, Dy, Ho, and Er. Efforts to prepare LaCo3B2, PrCo3B2, and NdCo3B2 by arc-melting were unsuccessful.
Theoretical Calculations and Assignments of Electronic Absorption Spectra of Cation Radicals of o-, m-, and p-Disubstituted Benzenes Having Amino and Hydroxyl Groups
Authors: Katsumata Shunji , Kimura Katsumi 
Published: July 2006

Abstract
Calculations have been carried out on the electronic spectra and electronic structures of the cation radicals of o-, m-, and p-disubstituted benzenes having the amino and hydroxyl groups, by an open shell SCF MO CI method involving some doubly excited electron configurations. Assignments of the electronic absorption spectra of these cation radicals have been made on the basis of resulting transition energies and oscillator strengths. The results are in good agreement with experimental data. Effects of methyl-substitution on the cation spectra are discussed. Spin densities of these cation radicals have also been calculated and compared with experimental data.
The Magnetic Properties of Some Iminoxyl Polyradicals. IV. The Paramagnetic Susceptibilities of the Diluted Crystals of the TEMPAD Biradical
Authors: Nakajima Akira 
Published: July 2006

Abstract
The paramagnetic susceptibilities of the diluted crystals of bis (2,2,6,6-tetramethylpiperidine-4)azine-1,1′-dioxyl (the TEMPAD biradical) have been measured from 1.8 to 77.3 K. The χM-T curves obey the Curie-Weiss law in the high and low temperature regions, and two kinds of the Weiss constant were found. The Weiss constant in the high-temperature region, which is caused by the strong inter-molecular exchange interaction, varies with the radical concentration from −8.5 to −15 K. The Weiss constant in the low-temperature region is of the order of magnitude of −1 K and reveals the existence of a weak intra-molecular exchange interaction. We can assume that the TEMPAD biradicals are distributed randomly in the matrix of the diamine and that they form either an isolated portion in which the weak intra-molecular exchange interaction exists only, or a clustering portion coupled by a strong inter-molecular exchange interaction besides the intra-molecular one. Then, the concentration dependence of the χM-T curves can be explained as the superposition of the contributions from these two portions. The curves caluclated on the assumption of the random distribution agreed with the experimental results.
The Dependence of the Electron-transfer Rates of Aromatic Hydrocarbon Anion Radicals upon the Molecular Radii of the Reactants
Authors: Suga Kosaku , Ishikawa Shin-ichi , Aoyagui Shigeru 
Published: July 2006

Abstract
The applicability of the theory of R. A. Marcus is tested, the behavior of the rate constant being examined as a function of the molecular radii of the reactants. The rate constants of the electron-transfer reactions from the anion radicals of pyrene, perylene, and tetracene to their respective parent molecules are measured under experimental conditions in which the anion radicals are in a free ion or loose ion-pair state. The rate constants thus obtained and subsequently corrected for diffusion are 2.8×109, 3.0×109, and 2.6×109 M−1sec−1 respectively, in 1,2-dimethoxyethane at 25°C. These rate constants, as well as others obtained elsewhere for naphthalene and anthracene, are compared with those predicted theoretically, assuming a spherical and an oblate spheroidal molecular shape. The consistence between the theoretical and experimental results is not satisfactory; the variation in the observed rate constants with the molecular radii of the reactants is much smaller than that expected theoretically. The spin-exchange rate constants for anion radicals of pyrene, perylene, and tetracene are also determined to be 7.0×109, 5.1×109, and 4.8×109 M−1sec−1 respectively, in the same solvent at 25°C.
Isothermal Decay of Trapped Electron in Irradiated 2-Methyltetrahydrofuran Glass
Authors: Ichikawa Tsuneki , Yoshida Hiroshi , Hayashi Koichiro 
Published: July 2006

Abstract
The isothermal decay of the electron trapped in gamma-irradiated 2-methyltetrahydrofuran glass was studied by electron spin resonance measurements at 92–95 K. Shape of the decay curves was found to be independent not only of radiation dose but also of temperature if they were plotted on the time scale in unit of half-life at each temperature studied. Although the decay follows neither a first order nor a second order reaction, the activation energy is able to be determined uniquely to be 0.8 eV. These results indicate that the mobilization of trapped electron is caused by repeated sequences of detrap-retrap due to thermal distortion or destruction of traps and that the evolution of decay is determined by the initial distribution of the electron-cation separation. On the basis of Nernst-Einstein assumption, the normalized distribution of the separation distance is numerically obtained and found to be close to a Gaussian function, though the absolute value of distance is unable to be determined because of the lack of knowledge of diffusion coefficient for the migration of electron in the glass. The effect of partial photobleaching of the trapped electron on the isothermal decay for the rest of electron was also studied and found to be the same as that of partial thermal bleaching.
Kinetics and Mechanism of the Reaction of Iodine Mono Chloride with Some Alcohols
Authors: Das C R , Bose A N 
Published: July 2006

Abstract
Kinetics of the reaction of ICl with some aliphatic alcohols, methanol to n-butanol and isobutyl alcohol and isopropyl alcohol, have been studied by the conductance method at five different temperatures. Arrhenius parameters have been determined. Plot of log k against the reciprocal of dielectric constant has been drawn to test the applicability of the Amis and Jaffé equation. Energy of activation has been correlated with polarity of alcohols. The IR analysis of the product shows a sharp peak at 1620 cm−1, which confirms a (O–I) bond stretching in the product. From these results a reasonable mechanism has been suggested as follows:
ICl\xrightarrowfastI++Cl− (1)
R–O–H+I+\xrightarrowslowR–O–I+H+ (2)
The Photolysis of Cyclopentanone
Authors: Tsunashima Shigeru , Ohsawa Osamu , Takahashi Chiharu , Sato Shin 
Published: July 2006

Abstract
The 326.1 nm direct photolysis and the cadmium-photosensitized reactions of cyclopentanone have been compared in order to clarify the role of the triplet state of cyclopentanone in the photolysis. The products observed in the both photolyses were carbon monoxide, ethylene, cyclobutane, and 4-pentenal. The results obtained in the direct photolysis were very similar to those obtained in the cadmium photosensitization. The ethylene/cyclobutane ratio was not affected by the pressure and temperature changes. The 4-pentenal/CO ratio increased with a decrease in the temperature. These similarities suggest that the decomposition of cyclopentanone takes place through the lowest triplet state in both the photolyses. The efficiency of cyclopentanone in quenching triplet cadmium was found to be about 0.8 times that of cis-2-butene.
Synthesis and Metal Chelate Stability of N,N′-Ethylenebis(aminomalonic) Acid
Authors: Mashihara Misao , Ando Takeshi , Murase Ichiro 
Published: July 2006

Abstract
N,N′-Ethylenebis(aminomalonic) acid (EAMA) has been synthesized, and its acid dissociation constants and the stability constants of its alkaline earth metal complexes were determined potentiometrically at 25°C in a medium of ionic strength of 0.10 (KNO3) with the following results: pK1=2.1, pK2=2.72, pK3=6.56, pK4=9.69; logKMY and logMMHY for Ca(II) respectively, 5.45 and 2.02; for Mg(II) respectively 4.93 and 1.80. The exact stability constants of Cu(II) and Ni(II) chelates of this ligand were not obtained on account of its decomposition in low pH solution, but the order of relative stability has been established. From a comparison of the stability of Ca(II) and Mg(II) chelates with those of the analogous complexane, the function of the malonate group in the chelate formation has been discussed. Zn(II) and Co(II) chelates of this ligand have been obtained and their probable structures are proposed.
Detosylation of N-Tosyl Amino Acids and Peptides by Electrolytic Reduction
Authors: Iwasaki Tameo , Matsumoto Kazuo , Matsuoka Manabu , Takahashi Takeo , Okumura Kentaro 
Published: July 2006

Abstract
An electrolytic reductive cleavage of tosyl group in N-tosyl amino acids was carried out by the use of 2 mol equivalent of NaCl or KCl as an electrolyte to the tosyl amino acids and of lead as a cathode in methanol–water. The procedure was applicable to the cleavage of N-tosyl peptides with preservation of the peptide bond, and with retention of their optical activity. No cleavage of the other protecting groups such as urethane type group and benzyl group was observed. The optimum conditions for reductive cleavage were found to be pH 11, lead being preferable to other cathode metals.
Studies of Organo Sulfur Compounds. II. The Preparation and Reactions of Benzoyl Benzenethiosulfonates
Authors: Kato Shinzi , Mizuta Masateru 
Published: July 2006

Abstract
Some mixed sulfonic thiocarboxylic anhydrides (II, R, R′: Aryl) were obtained from the reactions of potassium substituted-thiobenzoate with benzene- or p-toluenesulfonyl chlorides. The reactions of benzoyl benzenethiosulfonate were examined in comparison with those of the corresponding mixed sulfonic carboxylic anhydrides.
Solvolysis of Organic Phosphates. VI. Intramolecular Catalysis in the Hydrolysis of 2-Pyridylalkyl Phosphates
Authors: Murakami Yukito , Sunamoto Junzo , Kanamoto Naomi 
Published: July 2006

Abstract
The spontaneous hydrolysis of 2-pyridylethyl, 2-pyridylpropyl, and 6-methyl-2-pyridylmethyl phosphates was investigated at 80–95°C in aqueous media with an ionic strength of 0.10. The reactions followed apparent first-order kinetics with respect to the phosphate species, and the maximum rates were observed at −log[H+] 2–3 with a shoulder around 5–6. The participation of intramolecular catalysis played by the pyridinium group in the hydrolysis of the above pyridylalkyl phosphates as well as in that of 2-pyridylmethyl phosphate was investigated from the LFER viewpoint. For the evaluation of LFER, the acid dissociation constant was employed as the most reasonable structural parameter. As a result, the intramolecular pyridinium catalysis was found to takes place in the zwitterion hydrolysis for 2-pyridylmethyl, 2-pyridylethyl, and 6-methyl-2-pyridylmethyl phosphates. This indicates the importance of the geometry around the reaction center for the intramolecular catalytic action. The isokinetic relationship was established for the hydrolysis of pyridylalkyl phosphates with the exception of 6-methyl-2-pyridylmethyl phosphate. The anomalous behavior in the hydrolysis of the latter was attributed to the activation entropy effect which may have been caused by defreezing of solvation in the transition state.
The Synthesis and Absolute Configuration of Optically Active Tricyclo[4.3.0.03,8]nonane (Twist-brendane)
Authors: Naemura Koichiro , Nakazaki Masao 
Published: July 2006

Abstract
(−)-Tricyclo[4.3.0.03,8]nonane (“twist-brendane”) was synthesized via (−)-tricyclo[4.3.0.03,8]nonan-2-one (“twist-brendan-2-one”). The absolute configuration, (1R,3S,6S,8R)-tricyclo[4.3.0.03,8]nonane was assigned to (−)-twist-brendane by correlating with (−)-endo-5-carboxybicyclo[2.2.1]heptane.
Cyclopropanes from Olefins by the Oxygen-accelerated Zinc-carbenoid Reaction
Authors: Miyano Sotaro , Hashimoto Harukichi 
Published: July 2006

Abstract
Oxygen greatly accelerates the cyclopropanation of olefins by the diethylzinc-chloroiodomethane or -diiodomethane system. Olefins, including cyclohexene, cyclooctene, 1-heptene, 1-octene, 2-heptene, indene, n-butyl vinyl ether, styrene, and methyl oleate, gave the corresponding cyclopropanes in yields of ca. 70–100%. The methylene addition to cis- and trans-2-butene proceeded in a stereospecific manner in the presence of oxygen. Methyl methacrylate gave no appreciable amount of cyclopropanated product, but polymerization proceeded. Styrene inhibited the formation of the zinc-carbenoid reagent from diethylzinc and dihalomethanes under a nitrogen atmosphere. AIBN and UV light initiated the cyclopropanation of styrene with diethylzinc and chloroiodomethane. A free-radical-chain mechanism is proposed for the formation of the zinc-carbenoid reagent from diethylzinc and dihalomethanes.