bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactions of Metal Alkyl-Active Methylene Chelate Compounds with α,β-Unsaturated Carbonyl Compounds
Authors: Kawakami Yusuke , Tsuruta Teiji 
Published: July 2006

Abstract
The method of the preparation of zinc (or aluminum) alkyl-active methylene chelate compounds was studied. The chelate compounds were identified mainly by NMR, IR, and component analysis. Zinc alkyl-active methylene chelate compounds were found to cause a Michael-type addition reaction with α,β-unsaturated esters or nitriles. Aluminum alkyl-active methylene chelate compounds exhibited lower reactivities than the zinc chelate compounds toward α,β-unsaturated carbonyl compounds. Kinetic studies of the addition reaction revealed that the reaction proceeded according to a first-order rate law with respect to both the metal compound and the α,β-unsaturated carbonyl compound. The effects of substituents on the metal atom as well as on the chelate ring were also studied. The intercorrelation among the chemical shift of the methine proton of the chelate ring, σp of the subsituents and the reactivity of metal alkyl-active methylene chelate compounds suggested that the rate of the addition reaction was governed mainly by the stability of the chelate ring.
The Acid-catalyzed Reaction of Isocyanide with Oxetane
Authors: Saegusa Takeo , Taka-ishi Naotake , Ito Yoshihiko 
Published: July 2006

Abstract
The reaction of isocyanide with oxetane in the presence of BF3·OEt2 was studied; in this reaction a 1:1 cyclic adduct, 2-iminotetrahydrofuran, was formed. From 2-methyloxetane, 2-imino-5-methyltetrahydrofuran was exclusively formed. These findings suggest an SN2 mechanism for the cleavage of the oxetane ring. Oxetanes with electron-withdrawing substituents gave γ-alkoxybutyronitrile as the main product, along with 2-iminotetrahydrofuran. A reaction scheme involving an imidoyl cation was proposed to explain the formation of cyclic and linear products.
Photocycloaddition of Thiocarbonyl Compounds to Multiple Bonds. VII. The Reaction of Thiobenzophenone with Acetylenic Compounds
Authors: Ohno Atsuyoshi , Koizumi Tamotsu , Ohnishi Yutaka 
Published: July 2006

Abstract
Photocycloaddition of thiobenzophenone to acetylenic compounds, R–C≡C–R′ (R=COOH, Ph, CH2OH, and CN; R′=H: R=COOMe; R′=COOMe), affords 1-phenyl-2-thia-1,2-dihydronaphthalene derivatives. The key step to the product is an intra-molecular aromatic substitution of the composite vinylic biradical 13. The difference in reactivity of acetylenic and olefinic compounds as well as that between thiobenzophenone and benzophenone are discussed. Ethoxyacetylene does not undergo the reaction. This is interpreted in terms of electronegativity of a radical center in 13. It is found that cyanoacetylene reacts with butanethiyl radical in contrast to its olefin analog, acrylonitrile.
Selective Cleavage of Cysteine Peptides
Authors: Inui Toshishige 
Published: July 2006

Abstract
The cysteine peptides such as IV were cyclized to thiazolidone peptides through the corresponding S-chlorocarbonyl derivatives. In some peptides such as XXII, however, no cyclized products were isolated because of decomposition of the S-chlorocarbonyl intermediates. By the mild alkaline hydrolysis of the thiazolidone peptide the carboxylic acid from the N-terminal amino acid or peptide and 2-oxothiazolidine-4-carbonyl derivatives were isolated as a result of the selective cleavage of the peptide bond in which an amino group of cysteine residue participated. This cleavage reaction was applied to several cysteine peptides. The same results were observed whenever the corresponding thiazolidone peptides were formed.
Studies on Aminosugars. XXVII. Synthesis of Several Glycosides Containing (6-Amino-6-deoxy-d-glucopyranosyl)-2-deoxystreptamine
Authors: Nishimura Yoshio , Tsuchiya Tsutomu , Umezawa Sumio 
Published: July 2006

Abstract
Racemic O-isopropylidene derivative of N,N′-diethoxycarbonyl-2-deoxystreptamine was glycosidized with 6-azido-2,3,4-tri-O-benzyl-6-deoxy-α-d-glucopyranosyl chloride to afford two kinds of positional isomers of α-glucoside, which led to 4-O-(6-amino-6-deoxy-α-d-glucopyranosyl)- and 6-O-(6-amino-6-deoxy-α-d-glucopyranosyl)-2-deoxystreptamine. In a similar manner, 4-O-(6-amino-6-deoxy-α and β-d-glucopyranosyl)-6-O-(α-d-glucopyranosyl)-2-deoxystreptamines and 4-O-(6-amino-6-deoxy-α and β-d-glucopyranosyl)-6-O-(6-amino-6-deoxy-α-d-glucopyranosyl)-2-deoxystreptamines were synthesized.
Studies on Aminosugars. XXVIII. Synthesis of β-l-Idopyranosides through the Corresponding 5-Enopyranosides
Authors: Ikeda Daishiro , Tsuchiya Tsutomu , Umezawa Sumio 
Published: July 2006

Abstract
Methyl 6-deoxy-β-l-idopyranoside (7), methyl 2-amino-2,6-dideoxy-β-l-idopyranoside (13) and methyl 3-amino-3,6-dideoxy-β-l-idopyranoside (28) have been prepared through the corresponding suitably protected 5-enopyranoside precursors in good yields.
Intramolecular Fluorescence Quenching Effect by p-Nitrophenyl and p-Nitrophenoxy Groups
Authors: Mutai Kiyoshi 
Published: July 2006

Abstract
The intramolecular fluorescence quenching efficiency of p-nitrophenyl and p-nitrophenoxy groups in homologous series of p-O2NC6H4(CH2)nNH-1-Naphthyl (I, n=1–7) and p-O2NC6H4O(CH2)nNH-1-Naphthyl (II, n=2–6), respectively, has been determined. The quenching effect is observed even in the highest homologs of both series. From the fact that the fluorescence intensity of n=2 homolog of I is higher than that of n=1, together with spectroscopic data it is concluded that the higher intensity of n=2 than n=1 of the across-space intramolecular charge-transfer band is due to the larger absorbance per interacting molecule of n=2, the origin of which might be attributed to the different interacting conformations of these homologs. The effect of the number of methylene groups (n) on the fluorescence spectral shape has also been found.
An MO Interpretation of the Chemical Shifts of Inner-shell Electrons
Authors: Kato Hiroshi , Ishida Kazuhiro A , Nakatsuji Hiroshi , Yonezawa Teijiro 
Published: July 2006

Abstract
A correlation formula between the chemical shifts of inner-shell electrons and molecular-charge distributions is derived by an MO scheme with CNDO-type approximations. Errors imposed in these schemes are discussed. Reorganization energy terms are briefly discussed in the same level of approximations.
The Estimation of the Surface Properties of Metal Oxides by the Use of TCNQ Adsorption
Authors: Hosaka Hiroshi , Fujiwara Takao , Meguro Kenjiro 
Published: July 2006

Abstract
The electron-donor properties of metal oxides (magnesia, alumina, silica, titania, zinc oxide, and nickel oxide) were investigated by means of TCNQ adsorption. When TCNQ was adsorbed on the surfaces of the metal oxides from its acetonitrile solution, the surfaces of the metal oxides acquired the colorations characteristic of each oxide. The coloration was caused by the formation of TCNQ anion radicals on the metal oxide surfaces. The presence of the TCNQ anion radicals on the colored metal oxide surfaces was confirmed by studying the ESR absorption and electronic spectra. The radicals were formed as a result of electron transfer to TCNQ from the metal oxide surfaces. The order of the radical-forming activity, determined by ESR, was as follows: magnesia&gt;zinc oxide&gt;alumina&gt;titania&gt;silica&gt;nickel oxide. The electron-donor property of the metal oxide surfaces might be dependent on the natures of the semiconductor and the surface hydroxyl ion.
Effect of Phase on Hot Hydrogen Atom Abstraction Reaction with Solid Isobutane as Studied by Electron Spin Resonance Spectroscopy
Authors: Wakayama Terunobu , Miyazaki Tetsuo , Fueki Kenji , Kuri Zen-ichiro 
Published: July 2006

Abstract
The effect of phase on the hot-hydrogen-atom abstraction reaction with isobutane at 77°K has been studied by electron spin resonance spectroscopy in the photolysis and the radiolysis of solid isobutane containing hydrogen iodide. While only the isobutyl radical is formed by the UV-illumination of isobutane–hydrogen iodide systems in the polycrystalline state, the tertiary butyl radical, accompanied with a small amount of isobutyl radicals, is produced from isobutane-methylcyclohexane-hydrogen iodide systems in the glassy state. The hot hydrogen atom produced by dissociative electron attachment to hydrogen iodide abstracts the tertiary hydrogen atom from isobutane at 77°K, independent of whether the matrix is polycrystalline or glassy. It appears that the H-abstraction reaction from isobutane by hot hydrogen atoms depends upon the energy of the hot hydrogen atoms.
A New Method of Solubility Determination of Hydrolyzing Solute—Solubility of Benzyl Chloride in Water
Authors: Ohnishi Ryuichiro , Tanabe Kozo 
Published: July 2006

Abstract
A method of determining the solubility of a solute with a considerable rate of hydrolysis and small solubility in water was devised. The method consists of measurements of the hydrolysis rate below or at saturation solubility, the rate constants and order of reaction, and analysis of kinetic data. The solubility of benzyl chloride in water was found to be 33.1 mg/100 ml at 4.5°C, 49.3 at 20°C, and 55.5 at 30°C. Solubility of benzal chloride and benzotrichloride was calculated to be 25 mg/100 ml at 30°C and 5.3 at 5°C, respectively, by utilizing the kinetic data given in literature
The Crystal Structure of Ascochlorin p-Bromobenzenesulfonate
Authors: Nawata Yoshiharu , Iitaka Yoichi 
Published: July 2006

Abstract
The structure of ascochlorin, C23H29O4Cl, has been determined by the three-dimensional X-ray crystal structure analysis of ascochlorin p-bromobenzenesulfonate. The crystal is orthorhombic, space group P212123, with four molecules in a unit cell of dimensions, a=13.86, b=30.04, and c=6.82 Å. The structure was solved by the heavy atom method and refined by the method of block-matrix least-squares. The final R value was 0.102 for 1627 independent reflexions. Ascochlorin consists of (3-chloro) orcylic aldehyde and (2,3,4-trimethyl) cyclohexanone moieties which are connected with each other through a zigzag chain of trans-(3-methyl)penta(2,4)diene. The cyclohexanone ring takes a typical chair form, and the intramolecular hydrogen bond exists in the orcylic aldehyde residue. The absolute configuration was determined by the anomalous dispersion method.
Electrochemiluminescence of Aromatics in N,N-Dimethylformamide
Authors: Mori Kenji , Yamamoto Naoto , Tsubomura Hiroshi 
Published: July 2006

Abstract
Electrochemiluminescence (ECL) of aromatics was studied in dimethylformamide. The solutions were electrolyzed with square-wave voltage at various frequencies. For anthracene, emission from species produced by electrochemical reaction was observed together with anthracene fluorescence. These emissions were quenched when water was added to the solution. For rubrene and perylene, fluorescence from the molecules was observed. For phenanthrene, emission differing from phenanthrene fluorescence was observed at 515 mμ.
The Crystal Structure of 3-(10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ylidene)-1-ethy1-2-methylpyrrolidine Hydrobromide
Authors: Tokuma Yoji , Nojima Hiroshi , Morimoto Yukiyoshi 
Published: July 2006

Abstract
The crystal structure of 3-(10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ylidene)-1-ethyl-2-methllpyrrolidine hydrobromide, C22H26NBr, has been determined. The crystal is monoclinic with space group P21⁄a; the unit-cell dimensions are: a=30.16, b=18.78, c=7.048 Å, β=90.53°. The asymmetric unit contains two molecules. The intensities were estimated visually from the multiple-film equi-inclination Weissenberg photographs. The structure was solved by the heavy atom method. The atomic parameters were refined by the blockdiagonal least-squares method, and final R index was reduced to 0.147. It is concluded that the overall geometry of the two independent molecules is similar in every detail The pyrrolidine ring is puckered. The 10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ylidene part consists of three planes. The dihedral angles between the planes are 63° for the benzene planes I and II, 59° for the benzene plane I and the ylidene plane, and 76° for the benzene plane II and the ylidene plane.
The Chelating Behavior of 1-(2-Phosphonophenylazo)-2-hydroxynaphthalene-3,6-disulfonic Acid with Alkaline Earth Metals
Authors: Kina Kenyu , Miyata Haruo , Tôei Kyoji 
Published: July 2006

Abstract
A new chelating agent, o-phosphonophenylazo-2-hydroxynaphthalene-3,6-disulfonic acid, has been synthesized. The acid dissociation constants of this ligand and the chelate stability constants with alkaline earth metals have been measured by the pH titration method at an ionic strengh of 0.10 and at 25.0±0.1°C. This ligand forms the acido complex, MHL, in the pH 5–7 region. The stability constants of the acido complex decrease in this order: log KSrHL≈logKCaHL&gt;log KMgHL; whereas the decreasing order of the stability constants, logKML, is as follows: log KMgL&gt;log KCaL&gt;log KSrL.
The Stability of Fused Rings in Metal Chelates. VIII. Solution Equilibria of the Copper(II) Complexes of Glycinamide and Related Compounds
Authors: Yamaughi Osamu , Miyata Hiroko , Nakahara Akitsugu 
Published: July 2006

Abstract
The aqueous solution equilibria of the systems containing copper(II) ion and glycinamide, β-alaninamide, glycine-N,N-diethylamide, or β-alanine-N,N-diethylamide have been investigated by potentiometric titration at 25°C (μ=0.1 (KNO3)). The stability constants K1 and K2 and the constants of the deprotonation reactions K1H, Kc1, and Kc2, for the glycinamide-copper(II) systems, and K1 and K2 for the other ligand-copper(II) systerrs were calculated by the method of non-linear least-squares with the aid of a computer. The K1 values were found to be in the order, glycine-N,N-diethylamide (6.17)&gt;β-alanine-N,N-diethylamide (5.5)&gt;glycinamide (5.30)&gt;β-alaninamide (5.1). The sequence reveals that the five-membered chelates are more stable than the six-membered ones. The K1 and Kc1 values for glycylglycine and β-alanylglycine have been determined anew, and the structures of the chelates formed in acid solution have been discussed from comparative studies of the equilibrium constants, which suggest a tridentate nature of the dipeptides in the chelates of the type Cu(HL)+ where HL denotes free dipeptide.
The Crystal Structure of (+)589-Dicyanobis(ethylenediamine)cobalt(III) Chloride Monohydrate
Authors: Matsumoto Keiji , Ooi Shun’ichiro , Kuroya Hisao 
Published: July 2006

Abstract
The crystal structure of (+)589-[Co(CN)2en2]Cl·H2O has been determined from three-dimensional X-ray photographic data. The crystals are monoclinic, with the lattice constants of a=8.15(1), b=11.69(2), c=6.61(1) Å, and β=107.1(2)°, and with the space group of P21 containing two formula units in the cell. The structure was solved by a conventional Fourier technique and was refined by the least-squares method to an R factor of 0.114. The absolute configuration of the complex ion can be denoted as Λ(λλ); this is in accordance with the assignment made by Mason et al. The complex ion has an approximately two-fold axis, and both of the ethylenediamine chelate rings are of the ob-conformation.
The Polymerization of Silacyclopentene and -pentane Derivatives
Authors: Araki Tsunao , Terunuma Daiyo , Sato Tamio , Nagai Norio , Furuichi Mitsuharu , Nakamura Shigeyoshi 
Published: July 2006

Abstract
The polymerization of 1,1,3-trimethyl-1-silacyclopentene-3 (I), 1-methyl-, 1-allyl-1,1-diallyl-1-silacyclopentenes and -pentanes with aluminum chloride was carried out. By means of an IR spectroscopic analysis of the resulting polymers, it was established that not only ring opening but also vinyl polymerization due to the C–C double bond occur in this polymerization. Attempts to polymerize I with other catalysts, such as BF3·OEt2, AIBN, KOH, and a Ziegler catalyst, were unsuccessful.
p-Nitrophenyl Phosphates as Phosphoryiating Reagents of Alcohols
Authors: Chong Kyu-Jang , Hata Tsujiaki 
Published: July 2006

Abstract
Phosphorylation of alcohols by means of P1,P2-di-p-nitrophenyl pyrophosphate and p-nitrophenyl phosphate was investigated. Alcohols were phosphorylated in almost quantitative yields by use of P1,P2-di-p-nitrophenyl pyrophosphate. It was found that p-nitrophenyl phosphate acts as an effective phosphorylating reagent for alcohols in dry pyridine to give the corresponding alkyl phosphate.
Chemically Induced Dynamic Nuclear Polarization in the Photochemical Reaction of Phenanthraquinone with Hydrogen Donors. I. Kinetics of Nuclear Spin Polarization
Authors: Maruyama Kazuhiro , Shindo Heisaburo , Otsuki Tetsuo , Maruyama Tetsuo 
Published: July 2006

Abstract
Strongly-enhanced NMR signals were observed in the photo-induced hydrogen abstraction reaction of phenanthraquinone with several hydrogen donors in benzene. Chemically-induced dynamic nuclear polarization was kinetically treated in the photochemical reaction during the course of irradiation by visible light and shut-off. It was found that the relaxation time of the nuclear-spin system under the irradiation is shorter by a factor of 2 to 4 than that in the black-out stage and that the enhancement factor for the methine proton of the 1,2-adduct of phenanthraquinone was evaluated as 1000–2000.
The Solvent Effect on the Reaction Selectivity in the Chlorination of Propionic Acid
Authors: Nagai Toshikazu , Horikawa Yukio , Ryang Hon Son , Tokura Niichiro 
Published: July 2006

Abstract
The chlorinations of propionic acid with chlorine were carried out at 70°C in various solvent mixtures with photo-irradiation or with initiation by benzoyl peroxide. Benzene - CCl4, naphthalene - CCl4, and anthracene -CCl4 mixtures, and sulfur dioxide - CCl4 were used as the solvents. In the benzene - CCl4 mixtures, the relative reactivity, β/α, of the a and the α positions of propionic acid changed from 1.68 (CCl4) to 1.11 (benzene), the ratio being inversely proportional to the electron-donor properties of the solvents. In the naphthalene -CCl4 mixtures, the plot of the relative reactivity, β/α, versus the naphthalene content showed a minimun at ca. 0.1 mol/l of naphthalene; however, the total yield of the chlorinated acids decreased as the content of the naphthalene increased. No chlorinated acids were obtained in the anthracene - CCl4 system. In the presence of sulfur dioxide, the α-position was more readily substituted than the β-position, the β/α ratio decreasing as the molar ratios of C12/SO2 were decreased, from 1.3 (Cl2/SO2=0.286/0.036) to 0.49 (0.286/0.858), by the initiation of benzoyl peroxide. However, dilution with CCl4 or photo-irradiated chlorination cause no change in the selectivity in spite of the presence of sulfur dioxide. A mechanism to account for such a selectivity has been suggested.
Solvent Effect in a Partial Asymmetric Synthesis. III
Authors: Nishiyama Kazuyoshi , Inouye Yuzo 
Published: July 2006

Abstract
The solvent polarity-dependence of asymmetric stereochemistry was unambiguously corroborated in the Michael type cyclopropane formation in a system designed so as to proceed through the transition state conformations of an equal dipole moment not involving any geometrical isomerism: the NaH-catalyzed condensation of (−)-menthyl methacrylate with ethyl chloromalonate in solvent media of varying polarity resulted in the formation of (−)-1-methylcyclopropane-1,2,2-tricarboxylic acid having the same sign of rotation in all cases. The fit of the stereochemistry to the Kirkwood equation was borne out by the linearity found for the plots of logR⁄S against the Kirkwood-Onsager parameter. The R-configuration of (−)-1-methylcyclopropane-1,2,2-tricarboxylic acid was established by the correlation to (+)-2,2-diphenyl-1-methylcyclopropanecarboxylic acid of the well-defined (R)-configuration.
The Crystal and Molecular Structure of N-Salicylidene-α-aminoisobutyratoaquocopper(II)
Authors: Fujimaki Hiroto , Oonishi Isao , Muto Fumio , Nakahara Akitsugu , Komiyama Yoshimichi 
Published: July 2006

Abstract
The crystal structure of N-salicylidene-α-aminoisobutyratoaquocopper(II), [Cu{OOCC(CH3)2N=CHC6H4O}(H2O)], has been determined from the three-dimensional X-ray diffraction data. The crystals are monoclinic. The cell dimensions are: a=12.30, b=8.45, c=23.84 Å, and β=91.0°. The space group is P21/c, with eight formula units in a unit cell. The structure has been refined by the least-squares method, with anisotropic temperature factors, to an R-value of 0.10. The molecular structures of the complex are essentially the same as those of N-salicyl ideneglycinatoaquocopper(II) hemihydrate and tetrahydrate. The environments of the copper(II) ions are square pyramidal, with one long and four short coordination bonds. The average distances of the two copper environments are: Cu–O, 1.912 and 1.945; Cu–N, 1.961; Cu–O(H2O), 1.989, and Cu–O′ (the bond to the carboxyl oxygen of the adjacent molecule), 2.344 Å. The average bond distances of N=C in the salicylaldimine residue and of N–C in the α-aminoisobutyrate group are 1.271 and 1.504 Å respectively. Neighboring molecules related by a center of symmetry are linked together alternately by hydrogen bonds and coordination bonds (Cu–O′), an infinite chain being formed along the b-axis. However, there are no interactions other than van der Waals forces along the a- and c-axes.
Synthesis of cyclo-Diglycyl-l-tyrosyl-diglycyl-l-tyrosyl and Hydrolysis by Chymotrypsin
Authors: Konishi Mitsuhiro , Yoshida Norio , Izumiya Nobuo 
Published: July 2006

Abstract
A cyclic hexapeptide, cyclo-(diglycyl-l-tyrosyl)2, was synthesized by several different routes; the cyclization reactions of a tripeptide active ester, a tripeptide azide, and a hexapeptide azide produced the desired cyclic hexapeptide. The cyclic peptide was hydrolyzed slowly by chymotrypsin to a tripeptide diglycyl-tyrosine, whereas a synthetic linear hexapeptide, diglycyl-l-tyrosyl-diglycyl-l-tyrosine, was hydrolyzed very rapidly to the tripeptide. Since the synthetic cyclo-(diglycyl-l-phenylalanyl)2 was insoluble in a buffer, it was not clear whether an incubation mixture of the substrate and enzyme yielded diglycyl-phenylalanine.
The Reactions of Complexes of Thioboronite with Compounds Containing Carbon-Nitrogen Multiple Bond
Authors: Mukaiyama Teruaki , Yamamoto Shoji , Inomata Katsuhiko 
Published: July 2006

Abstract
n-Butyl di-n-butylthioboronite reacts with isocyanates to give 1:2 adducts, and with isothiocyanate or carbodiimide to give a 1:1 adduct. It was found that thioboronite forms a 1:1 co-ordinated complex with benzyl cyanide, and that the complex reacts with isocyanates to give the corresponding acetamidine derivatives in good yields.
Preparation of p-Toluenesulfonyl Derivatives of myo-Inositol
Authors: Suami Tetsuo , Ogawa Seiichiro , Oki Shuichi 
Published: July 2006

Abstract
Six p-toluenesulfonyl esters of myo-inositol, five of which are new, have been prepared by a selective sulfonylation of myo-inositol derivatives and the structures of the new compounds were established by means of their proton magnetic resonance (PMR) spectra and the reaction sequences. Preparation of 1,3-di-O-p-toluenesulfonyl-myo-inositol, an useful intermediary compound for synthesizing myo-inosadiamine-1,3, has been improved by the present method.