bluuebunny/crossref_metadata_2025_split huggingface dataset:
Liquid-phase Adsorption from Binary Solutions on Silica Gel. The Apparent Separation Factors and the Distribution of Adsorption Sites
Authors: Kagiya Tsutomu , Sumida Yūzō , Tachi Toshihiro 
Published: July 2006

Abstract
The liquid-phase adsorption equilibrium of a cyclohexane-benzene mixture on a silica-gel surface, containing various quantities of physically-adsorbed water, has been studied at 30°C. The apparent separation factors (αap) have been determined on the assumption that this liquid-phase adsorption is of the Langmuir-type. It was found that the values of αap were, in general, markedly affected not only by the composition of binary solvents, but also by the amounts of physically-adsorbed water. In order to discuss this point quantitatively, the theoretical equation for estimating the apparent separation factors on a complicated solid surface having two or more types of adsorption sites has been derived on the basis of the theory of chemical equilibrium. The following three types of adsorption sites have been assumed to exist on the silica-gel surface used in this experiment: the surface silanol (σ1), the monolayer of water (σ2), and the multilayer of water (σ3). The separation factors of the σ1 and σ3 were experimentally measured as 17.1 and 2.5. By best-fitting the above theoretical equation for αap with the observed values, the separation factor of the σ2 site was taken to be 3.7 and the distribution of each adsorption site on the surface was determined.
The Crystal and Molecular Structure of Dimethyltin Bis(N,N-dimethyldithiocarbamate)
Authors: Kimura Toshihide , Yasuoka Noritake , Kasai Nobutami , Kakudo Masao 
Published: July 2006

Abstract
The crystal and molecular structure of dimethyltin bis(N,N-dimethyldithiocarbamate), [(CH3)2Sn{S2CN-(CH3)2}2], has been determined by single crystal X-ray diffraction. The crystals are orthorhombic; Fdd2; a=25.478±0.008, b=35.323±0.011, c=6.936±0.006 Å, Z=16. The tin atom has a distorted octahedral environment. The tin atom and the four sulfur atoms lie approximately on the same plane, with two Sn–S bond distances of 2.515±0.008 and 2.497±0.008 Å and two longer Sn-S distances of 2.954±0.007 and 3.061±0.008 Å, while the methyl groups are in trans positions; average Sn–C=2.15±0.04 Å. The SnSC(S)N skeletons on both sides of the tin atom are approximately planar, and the average bond distances are S–C=1.72±0.03, C–N=1.31±0.03, and N–C(Me)=1.49±0.04 Å.
An ESR Study of Some Substituted Pyridine N-Oxide Copper(II) Complexes
Authors: Freyberg Derek P , Isobe Toshiyuki , Misumi Seizo 
Published: July 2006

Abstract
The ESR (methanol solution, frozen solution, powder, and single crystal) spectra of [CuL4](ClO4)2, where L=pyridine N-oxide, α-picoline N-oxide, β-picoline N-oxide, γ-picoline N-oxide, and 2,6-lutidine N-oxide, and of [CuL6](ClO4)2, where L=pyridine N-oxide and γ-picoline N-oxide, have been obtained. The preparation of hexa(γ-picoline N-oxide) copper(II) perchlorate is reported. The solution and frozen solution spectra indicate a very similar bonding in all the complexes, with moderately ionic metal-oxygen. The powder spectra reveal all the tetrakis complexes to be axially symmetric; though tetra(γ-picoline N-oxide) copper(II) perchlorate shows a reversal of the usual order of the g-values. This is explained in terms of the packing interactions within the crystal structure, rather than metal-ligand interaction. All the single crystal spectra are characteristic of axially symmetric complexes. Hexa(pyridine N-oxide)copper(II) perchlorate gives an isotropic ESR spectrum, but this does not seem to be due to exchange interaction. Hexa(γ-picoline N-oxide)copper(II) perchlorate gives an axial ESR spectrum with a considerable tetragonal misalignment.
Transfer-hydrogenation and Transfer-hydrogenolysis. I. Transfer-hydrogenation of Cyclooctadienes Catalyzed by Dichlorobis(triphenylphosphine)iron(II)
Authors: Nishiguchi Takeshi , Fukuzumi Kazuo 
Published: July 2006

Abstract
Hydrogen transfer from a number of organic compounds to olefins in a homogeneous system was studied. In the case of hydrogen transfer to 1,5-cyclooctadiene, using dichlorobis(triphenylphosphine)iron(II) as the catalyst, dihydroxybenzenes, such as pyrocatechol and hydroquinone, were much superior to prim- and sec-alcohols, 1-dodecanethiol, and cyclohexene as hydrogen donors.
Far Infrared Spectra and the Calculation of Lattice Vibrations of Benzoic Acid
Authors: Meshitsuka Shunsuke , Takahashi Hiroaki , Higasi Keniti , Schrader Bernhard 
Published: July 2006

Abstract
Polarized far infrared spectra from 400 to 30 cm−1 of benzoic acid single crystals have been measured. Three bands polarized parallel to the C2s screw axis b were observed at 104, 86, and 62 cm−1, and three bands polarized parallel to the a-axis at 106, 76, and 65 cm−1. The lattice vibrations of benzoic acid have been calculated assuming the rigidity of the molecule during the lattice vibrations and applying a simple force field. The bands at 104, 86, and 62 cm−1 were assigned to the rotational vibrations of Au symmetry species: the O–H···O stretching, the ring torsional and the O–H···O out-of-plane bending modes, respectively, and the bands at 106, 76, and 65 cm−1to those of Bu symmetry species. The force constant K(O···H) related to the hydrogen bonds in the cyclic dimer was calculated to be 0.35 mdyn/Å.
The Abnormal Absorption Intensity of the C–H Stretching Vibration Band in Chloroform Vapor. II.
Authors: Miyazaki Tomoo , Yamamoto Hiroshi 
Published: July 2006

Abstract
By CNDO calculations considering the 3d orbitals of the chlorine atom, the infrared absorption intensity of the C–H stretching vibration band in chloroform vapor has been discussed in comparison with those of methyl chloride and methylene chloride. The absolute intensities of the fundamental and the first-overtone bands of these compounds have been calculated in view of the mechanical and the electrical anharmoniciteis of the vibrating bond. From the results of these calculations, it was revealed that the contribution of the electrical properties of the vibrating bond to the abnormal absorption intensity of the C–H stretching vibration band in chloroform vapor is really greater than that of the mechanical anharmonicity.
The Reactions of 80Br Activated by the (n,γ) Process with Methane
Authors: Saeki Masakatsu , Numakura Kenshi , Tachikawa Enzo 
Published: July 2006

Abstract
The reactions of 80Br activated by the (n,γ) process with CH4 have been examined. By assuming that the limiting yields of products at 1.0 m.f. of the Kr-moderator is due to thermal ionic processes, the kinetic yields were tentatively determined to be the 12.4% for total organic, 11.4% for CH380Br, and 1.0% for CH280BrBr. A similar treatment of the results from the reactions with CD4 gives 5.1% for total organic, 3.9% for CD380Br, and 1.2% for CD280BrBr. When the CH380Br yield was compared with that from the reactions of 80Br from the (I.T.) activation, a noticeable difference was noticed; it was roughly 3 times as large as in the latter system. Furthermore, the pressure effects on the CH380Br show that a fraction of CH380Br is highly excited and is able to decompose even at a pressure of 1920 mmHg. This suggests that the distribution of 80Br in the reaction energy range extends to a higher energy than in the case of 80Br activated by the (I.T.) process.
Crystal Growth of β-Hopeite on (0001) Plane of a Single Crystal of Zinc
Authors: Okuwaki Akitsugu , Ninagawa Jinichi , Okabe Taijiro , Omori Keiichi 
Published: July 2006

Abstract
The epitaxy and the orientation of β-hopeite grown on the (0001) plane of a single crystal of zinc were studied. The epitaxy was found to be (0001)-Zn//(010)-β-hopeite, and the orientation was [10.0]//[100] or [12.0]//[100]. The nature of the chemical bond between β-hopeite and zinc is considered to be similar to that of the wurtzite type rather than to that of the wüstite type in view of the structure of the boundary surfaces.
Interaction between Organoaluminum Compounds and Ditertiary Phosphines Studied by Proton Magnetic Resonance
Authors: Kagawa Teruhiko , Hashimoto Harukichi 
Published: July 2006

Abstract
The adduct formation of triethylaluminum or diethylaluminum chloride with ditertiary phosphines (Ph2-P(CH2)nPPh2 n=1,2,3,4, and 6) in benzene solution was investigated by PMR. The adducts have a composition of (AlEt3)2 (diphosphine) except in the case of Ph2PCH2PPh2, which makes two kinds of adducts (1:1 and 2:1). Electronegativity of the complexed aluminum is also calculated from Dailey-Shoolery equation.
Thermal Properties of Copper(II) Chelates of Some 1,5-Alkylpentane-2,4-diones
Authors: Yoshida Isao , Oono Yoshitsugu , Kobayashi Hiroshi , Ueno Keihei 
Published: July 2006

Abstract
Thermally stable and low melting copper(II) chelates of β-diketones have been synthesized as follows; bis-(heptane-2,4-dionato)copper(II), mp 172°C; bis(nonane-4,6-dionato)copper(II), mp 162°C; bis(5-ethylheptane-2,4-dionato)copper(II), mp 72°C; bis(3-ethylnonane-4,6-dionato)copper(II), mp 50°C; bis(3,7-diethylnonane-4,6-dionato)copper(II), mp 58°C. Their thermal characteristics including enthalpy and entropy of fusion, have been discussed in relation with the molecular structure of the copper chelates.
Studies on Stable Free Radicals. XI. ESR Spectra of Stable Nitroxide Biradicals
Authors: Toda Toshimasa , Mori Eiko , Murayama Keisuke 
Published: July 2006

Abstract
The ESR spectra of the triplet state of stable nitroxide biradicals, 1,9-diaza-2,2,8,8,10,10-hexamethyl-4-oxospiro[5.5]-undecane-1,9-dioxyl (III), cyclohexane-1-spiro-2′-(4′-oxoimidazolidine)-5′-spiro-4″-(2″,2″,6″,6″-tetramethylpiperidine)-1′, 1″-dioxyl (IV) and cyclohexane-1-spiro-2′-(3′-oxoimidazolidine)-5′-spiro-4″-(2″,2″,-6″,6″-tetramethylpiperidine)-1′,1″-dioxyl (V) have been observed in a frozen MTHF glass. The biradicals have 2D\simeq500 and E\simeq0 gauss. The distance (I\simeq5 Å) between the two radical sites in these biradicals indicates that one piperidine ring can exist in chair form and the other in twisted form in III, and both in the twisted form in IV and V. The biradical, 2,2,6,6-tetramethylpiperidine-4-spiro-2′-(4′-oxoimidazolidine)-5′-spiro-4″-(2″,2″,-6″,6″-tetramethylpiperidine)-1,1″-dioxyl (VI) in a MTHF frozen glass shows no spectrum corresponding to a triplet state.
Intramolecular Hydrogen Bonds. XVIII. Intramolecular Hydrogen Bonding in Ethyl α- and β-Alkylamino-alkanoates
Authors: Mori Nobuo , Aihara Masanori , Asabe Yoshihiro , Tsuzuki Yojiro 
Published: July 2006

Abstract
The intramolecular hydrogen bonding in ethyl ω-alkylamino-acetates and -propionates in dilute carbon tetrachloride solutions has been investigated through the measurement of the NH and CO stretching absorption spectra. In the α-esters, the spectral data give no evidence regarding the hydrogen-bond formation. In the β-esters, though, the hydrogen bonding occurs, probably predominantly between the NH and the CO group.
Studies on Separation of Amino Acids and Related Compounds. VII. Separation of l-Aspartyl-(α,β)-l-histidine and of l-Glutamyl-(α,γ)-l-histidine
Authors: Hirata Mitsuteru , Noda Kosaku , Izumiya Nobuo 
Published: July 2006

Abstract
As control compounds, the structural α- and ω-isomers of l-aspartyl- and l-glutamyl-l-histidine were synthesized by a conventional manner. The experiments on a column chromatography of Dowex 50 were carried out with a model mixture containing α- and ω-isomer, and the complete separation of the isomers was observed at acidic condition. A mixture of α- and ω-isomers of l-aspartyl- or l-glutamyl-l-histidine prepared through the coupling of benzyloxycarbonyl-l-aspartic or glutamic acid anhydride with l-histidine were separated into each isomer with a large column in moderate yields.
The Reduction of Stereoisomeric 6-tert-Butyl-3-methoxy-3-methylcyclohexenes with Lithium in Ethylamine
Authors: Masamune Tadashi , Matsue Hajime , Fujii Matsuo 
Published: July 2006

Abstract
The synthesis and reduction with lithium in ethylamine of the entitled stereoisomeric allyl ethers 1 and 2 are described. The reaction of both the isomers occurred very readily with concomitant cleavage of the methoxy groups, and gave the same products, 4-tert-butyl-1 -methylcyclohexene (13), and c- and t-3-tert-butyl-6-methylcyclohex-1-enes (14 and 15), in the same ratio (87 : 4 : 9), indicating that the respective reactions involved a common intermediate (16). Moreover, the reduction of the cis-isomer 1 with an axial methoxy group proceeded much more rapidly than that of the trans-isomer 2 with an equatorial methoxy.
Methylene Analogs of Cyclobutenedione. III. The Reaction of 2-Bromo- and 2,2-Dibromo-3,4-bis(diphenylmethylene)cyclobutanone with Alcoholic Potassium Hydroxide
Authors: Toda Fumio , Takehira Yoshikazu 
Published: July 2006

Abstract
The reactions of 2-bromo-3,4-bis(diphenylmethylene)cyclobutanone (III) with methanolic and 2-propanolic potassium hydroxide afforded methyl 4-methoxy-2,3-bis(diphenylmethylene)butyrate (VIII) and 3,4-bis-(diphenylmethylene)-γ-lactone (XXI) respectively. The reaction of the 2,2-dibromo analog of III (XXV) with methanolic potassium hydroxide afforded methyl 4-methoxy-4-bromo-2,3-bis(diphenylmethylene)butyrate (XXVIIIa) and methyl 4,4-diphenyl-3-formyl-2-diphenylmethylenebut-3-enate (XXIIIa) in approximately equal yields. However, the reaction of XXV with 2-propanolic potassium hydroxide afforded XXIIIc exclusively. The reaction mechanism was disclosed to be that the haloester intermediates V and XXVII initially formed from III and XXV respectively, by the addition of alcohol to the carbonyl followed by the ring-opening, react with the alkoxy and hydroxy anions competitively.
Isolation and Structure Proof of Dinitrocyclohexenones Formed in the Nitration of Polyalkylbenzenes with Fuming Nitric Acid
Authors: Suzuki Hitomi , Sawaki Mikio , Sakimoto Reiji 
Published: July 2006

Abstract
Action of fuming nitric acid upon 1,2,3,5-tetramethylbenzene and 2-ethyl-1,3,5-trimethylbenzene at low temperature was found to yield small amounts of dinitrocyclohexenones in addition to the ring nitration and side-chain nitrooxylation products. Chromatographic separation over silica gel followed by spectral investigation established the structures of these nitro-ketones to be 2,3,4,6-tetramethyl-5,6-dinitro-3-cyclohexen-1-one and 2,4,6-trimethyl-3-ethyl-5,6-dinitro-3-cyclohexen-1-one respectively. The mechanistic interpretation of their formation was briefly discussed.
The Photo-Beckmann Rearrangement of 3α,5-Cyclo-5α-cholestan-6-one Oxime
Authors: Suginome Hiroshi , Takahashi Hajime , Masamune Tadashi 
Published: July 2006

Abstract
Photolysis of 3α,5-cyclo-5α-cholestan-6-one oxime affords two isomeric lactams with cyclopropane rings arising from photo-Beckmann rearrangement although the yields are poor. The result gives further support to our view on the C→N migration process in photo-Beckmann rearrangement. The major part of the products of the reaction consisted of the parent ketone and several products probably derived from it. The results are compared with those obtained in our photolysis of 5α-cholestan-6-one oxime and the isomeric 5β-cholestan-6-one oximes. The poor yields of the lactams is probably ascribable to the presence of the cyclopropane ring in this conjugated cyclopropyl ketone oxime.
The Structure of κ-Carrageenan from Gigartina Tenella
Authors: Hirase Susumu , Watanabe Kyoko 
Published: July 2006

Abstract
An alkaline treatment of κ-carrageenan from Gigartina tenella resulted in the change of the proportions of galactose, 3,6-anhydro-galactose and sulfate from 100 : 91 : 124 to 95 : 96 : 119. Fragmentation of the methylated polysaccharide gave 2,4,6-tri-O-, 2,6-di-O-, and mono-O-methyl-d-galactose in the molar proportions of 1 : 18 : 0.8 together with 3,6-anhydro-d-galactose and its 2-O-methyl-derivative in the molar proportion of 1 : 4. From these and other data, it is concluded that the polysaccharide is composed of the residues of 1,3-linked β-d-galactose 4-sulfate (95 mol), 1,4-linked α-d-galactose 6-sulfate (5 mol), and 1,4-linked 3,6-anhydro-α-d-galactose (67 mol) and its 2-sulfate (24 mol), and that the 1,3- and 1,4-linked residues are repeated alternatingly to form a chain macro-molecule.
Studies on Stable Free Radicals. XII. ESR Spectra of 2-t-Butylaminotropone N-Oxyl Radicals
Authors: Toda Toshimasa , Mori Eiko , Murayama Keisuke 
Published: July 2006

Abstract
We observed a well resolved ESR spectrum of 2-t-butylaminotropone N-oxyl radical generated by the oxidation of the corresponding amine with perbenzoic acid, and assigned the values of hyperfine coupling constants of protons in the tropone ring by a comparison with the ESR spectra of deuterium substituted 2-t-butylaminotropone N-oxyl radicals: aN=12.7 gauss, aH3=aH5=aH7=1.86 gauss and aH4=aH6=0.93 gauss for protons on tropone ring.
The Oxidation of (+)-3-Carene and the Related Compounds with t-Butyl Chromate
Authors: Suga Takayuki , Shishibori Tsuyoshi , Matsuura Tamon 
Published: July 2006

Abstract
The oxidation of (+)-3-carene with t-butyl chromate was found to afford 3,α-dimethylstyrene (2), eucarvone (3), 1,1,4-trimethylcyclohepta-2,4-dien-6-one (4), 3-methylacetophenone (5), 8-hydroxy-m-cymene (6), car-3-en-2-one (7), (−)-car-3-en-5-one (8), and (−)-car-3-ene-2,5-dione (9). The aromatized compound (6) was a major product in the oxidation in an acidic medium, whereas the oxidation in the neutral and the basic media gave the enedione (9) and the enone (8) as major products. It was, furthermore, proved that methylenes adjacent to the cyclopropane ring of (−)-cis-carane (10) and (+)-caran-3β-ol (11) were scarcely attacked by t-butyl chromate.
The 1-Methylene Derivatives of [7](2,6)Pyridinophane. Preparative and Conformational Studies
Authors: Fujita Shinsaku , Imamura Kazuo , Nozaki Hitosi 
Published: July 2006

Abstract
The 1-exo-methylene derivatives (IV, V and VII) of [7](2,6)pyridinophane (I) are synthesized by Wittig’s reaction of [7](2,6)pyridinophan-1-one (III) or by the dehydration of the corresponding carbinol (VI). The C-4 protons are all shielded magnetically to varying extents, depending on their respective 1-substituents. The shielding effect is ascribed to the anisotropy of the pyridine ring. The signals of the C-4 protons are temperature-dependent, and the energy barriers for the conformational changes are estimated to be 8.7 for III, 9.1 for IV, 9.1 for V and 9.8 kcal/mol for VII.
Synthetic Reactions by Complex Catalysts. XXVI. The Copper-catalyzed Reaction of α,β-Unsaturated Isocyanide with Active Methylene Compounds
Authors: Saegusa Takeo , Murase Ichiki , Ito Yoshihiko 
Published: July 2006

Abstract
The Cu2O-catalyzed reaction of α,β-unsaturated isonitrile with active methylene compound is described. Vinyl isocyanide (VIC) and propenyl isocyanide (PPIC) were employed as the isocyanide components. In addition, allyl isocyanide (AIC), which has been known to be rearranged readily to PPIC by Cu2O, was also used as a precursor of PPIC. Five types of products were isolated and identified. These products were explained by a scheme starting with an intermediate of the organocopper-isonitrile complex (9) derived from the active methylene compound.
The Synthesis of the 1,2,4-Thiadiazine-1,1-dioxides
Authors: Hasegawa Kiyoshi , Hirooka Syuzi 
Published: July 2006

Abstract
N-(2-Phenylethene-1-sulfonyl)-N′-monoalkyl S-methylisothioureas, 2, were ring-closed to yield Michael cycloadducts, 3-methylthio-4-alkyl-5-phenyl-1,1-dioxo-5,6-dihydro-1,2,4-thiadiazines, 3. Bulky N′-alkyl groups hindered the cycloaddition. The base-catalyzed hydrolysis of 3 and 3-chloro-derivatives 4 gave 4-methyl-5-phenyl-2,3,5,6-tetrahydro-1,1,3-trioxo-1,2,4-thiadiazines, 5, which in turn underwent N-alkylation to give 6. The reaction of 4 with amines or with sodium methoxide yielded 3-amino-, 7, or 3-methoxy-thiadiazine derivatives, 9.
The Effect of the Wavelength of an Exciting Light on Four-center-type Photopolymerization in the Crystalline State
Authors: Tamaki Takashi , Suzuki Yasuzo , Hasegawa Masaki 
Published: July 2006

Abstract
The effect of the wavelength of an exciting light on four-center-type photopolymerization in the crystalline state has been investigated. 2,5-Distyrylpyrazine (DSP), 1,4-bis[β-pyridyl-(2)vinyl]benzene (P2VB), p-phenylenediacrylic acid (p-PDA) dimethyl ester were converted quantitatively into highly crystalline oligomers (pentamers on the average) on irradiation at the long-wavelength edge of the absorption of the monomer. On subsequent exposure to the light which is absorbed by each oligomer, the oligomer crystals as-polymerized were converted quantitatively into high polymer crystals. The polymer thus obtained was found to be identical with the polymer produced by the light of a xenon or a high-pressure mercury lamp. The quantum yields for the oligomerization and polymerization reactions of DSP and the p-PDA dimethyl ester were found to be between 1 and 2 on the basis of the number of olefinic double bonds consumed to form the cyclobutane ring. These results confirmed that the four-center-type photopolymerization in the crystalline state consists of two kinds of separable, step-by-step addition mechanisms: an oligomerization of the dioleflnic compound and a growth reaction of the terminal group in the growing chain. From the crystallographic information on the DSP oligomer, the oligomerization as well as the polymerization process of DSP were concluded to proceed by a monomer lattice-controlled mechanism.
Conformations of the Esters. VI. The Conformations of Monothiocarbonates
Authors: Oki Michinori , Nakanishi Hiroshi 
Published: July 2006

Abstract
The presence of two or three conformational isomers in monothiocarbonates has been confirmed by nuclear magnetic resonance and infrared spectroscopies and by dipole moment techniques. The data can best be interpreted by assuming that the conformations involving the s-cis conformation are more stable than that of s-trans, s-trans.
Oxidation by Transition Metal Complexes. V. Oxidation of Vinyl Esters Catalyzed by Rhodium Complex.
Authors: Takao Kiyotomi , Azuma Hiromichi , Fujiwara Yuzo , Imanaka Toshinobu , Teranishi Shiichiro 
Published: July 2006

Abstract
The oxidation of styryl acetate, vinyl acetate, vinyl propionate, methyl acrylate, and methyl cinnamate with RhCl(PPh3)3 catalyst has been studied. The reaction is remarkably affected by the substituent on an olefinic carbon atom. The oxidation mechanism was discussed in connection with decarbonylation.
The Additive Effect of Triphenylphosphine on the Polymerization of Vinyl Monomers by Copper(II) Chelates
Authors: Shono Toshiyuki , Yamashoji Yuko , Shinra Koichiro 
Published: July 2006

Abstract
Various copper(II) chelates were found to be effective initiators in the polymerization reaction of the methyl methacrylate in the presence of triphenylphosphine. The conversion increases with an increase in the concentration of triphenylphosphine, reaching a constant level at the ratio of 1: 2 between copper chelates and triphenylphosphine. Di-μ-methoxo-bis(ethylacetoacetato)dicopper(II) was the most effective initiator. The dependence of the rate of the polymerization on the square root of the concentration of the complexes suggests that the polymerization by this initiation system proceeds via a radical mechanism. It can be assumed that the copper chelate coordinated the triphenylphosphine and that homolytic fission occurred to give a free ligand radical, accompanied by the reduction of the central copper atom. Stable copper (I) mixed chelates were obtained under conditions similar to those of the polymerization.