bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Thermal Rearrangement of Homobarrelenones. Preparation of Dimethyl 1-Oxo-cis-3a,7a-dihydroindene-3a,7a-dicarboxylates
Authors: Uyehara Tadao , Miyakoshi Shoichi , Kitahara Yoshio 
Published: July 2006

Abstract
The Diels-Alder reaction of five derivatives of 2-methoxytropone with dimethyl acetylenedicarboxylate proceeds regiospecifically giving dimethyl 1-methoxy-2-oxobicyclo[3.2.2]nona-3,6,8-triene-6,7-dicarboxylates, except in the case of 5-isopropyl-2-methoxytropone. The adducts undergo rearrangement selectively to dimethyl 7-methoxy-1-oxo-cis-3a,7a-dihydroindene-3a,7a-dicarboxylates, upon heating under reflux in xylene. Regiochemical aspects of the cycloaddition and mechanistic aspects of the rearrangement are discussed.
Photolyses of Tetraphenylcyclobutanes at 254 nm
Authors: Shizuka Haruo , Seki Ichiro , Morita Toshifumi , Iizuka Takeshi 
Published: July 2006

Abstract
Photolyses of 1,2,3,4-tetraphenylcyclobutanes (TPCB) at 254 nm in hydrocarbon solvents have been studied by means of fluorometry, nanosecond time-resolved spectroscopy, and measurements of the reaction quantum yields. The photolysis of TPCB originates from the S1(π,π*) state to give trans-stilbene nearly concertedly at higher temperatures (&gt;200 K). Significant temperature and cis-effects were observed. The radiationless rate constants for the dissociation (kr) and the other radiationless (kn) processes decreased with lowering temperature. The value of kr for γ-1,t-2,t-3,c-4-TPCB at 300 K, for example, was 4.7 times greater than that for γ-1,t-2,c-3,t-4-TPCB. The Arrhenius parameters of the relaxation processes were also determined. No intramolecular excimer emission was observed.
Conformational Analysis of Intramolecular Fluorescence Quenching of α-(9-Carbazolyl)–ω-[p-(methoxycarbonyl)benzoyloxy]alkanes
Authors: Kanaya Toshiji , Hatano Yoshihiko , Yamamoto Masahide , Nishijima Yasunori 
Published: July 2006

Abstract
Equilibrium distribution of conformations of the series of compounds, α-(9-carbazolyl)-ω-[p-(methoxycarbonyl)benzoyloxy]alkanes in the ground state was calculated to explain the intramolecular fluorescence quenching of these compounds in a rigid medium. It was found that when the radius of active sphere R0 for the intramolecular fluorescence quenching is taken to be 8.8–9.0 Å, the experimentally observed chain length dependence of the fluorescence quenching can be well simulated by this calculation. The active sphere for the dynamic intermolecular fluorescence quenching in solution was also discussed to compare with that of the intramolecular fluorescence quenching.
Film Dichroism. III. Linearly-polarized Absorption Spectra of Highly Symmetric Triphenylmethane Dyes in the Stretched Poly(vinyl alcohol) Films
Authors: Matsuoka Yukio , Yamaoka Kiwamu 
Published: July 2006

Abstract
The linear dichroic absorption spectra of Pararosaniline (PR), Crystal Violet (CV), and Ethyl Violet (EV) were measured in the UV and visible regions by the stretched film technique. Poly(vinyl alcohol) was used as the film matrix. A method, which is expressed in the forms of reduced dichroism and dichroic ratio, was proposed for the analysis of the linear dichroism of disk-like molecules. The dyes PR, CV, and EV were shown to behave like disks regarding their orientation in the polymer matrix. The isotropic absorption spectra of PR, CV, and EV were resolved into the in-plane and out-of-plane polarized components by the reduction procedure. In each isotropic spectrum the out-of-plane component was found to overlap with the intense in-plane component in the UV and visible wavelength regions.
Mechanism for Reaction of p-Nitrotoluene with Sodium Polysulfide to Form p-Aminobenzaldehyde
Authors: Ogata Yoshiro , Kawasaki Atsushi , Sawaki Yasuhiko , Nakagawa Yoshiaki 
Published: July 2006

Abstract
The conversion of p-nitrotoluene to p-aminobenzaldehyde was found to be most effectively done by a mixture of Na2S4 and ca. two equivalents of NaOH to p-nitrotoluene. After examination of probable intermediates, toluidine, p-nitrobenzaldehyde and p-nitrosotoluene were discarded as the intermediate. The reaction of carbanion ArCO\={C}HAr with the sulith the sulfide and the effect of some nitrobenzenes as an electron accepter were examined. These results suggest a mechanism involving a simultaneous oxidation-reduction in a nitrotoluene molecule.
The Structure of the Cyclodextrin Complex. VIII. Crystal Structures of α-Cyclodextrin Complexes with 2-Pyrrolidone and N,N-Dimethylformamide
Authors: Harata Kazuaki 
Published: July 2006

Abstract
Crystal structures of α-cyclodextrin complexes with N,N-dimethylformamide and 2-pyrrolidone were determined by the X-ray method. The pentahydrated crystals of both complexes are orthorhombic, and the space group is P212121 with Z=4. The cell dimensions are a=13.750(1), b=15.318(1), and c=24.544(2) Å for the N,N-dimethylformamide complex, and a=13.852(1), b=15.373(1), and c=24.353(2) Å for the 2-pyrrolidone complex. The structures were determined by assuming the same α-cyclodextrin packing in the crystal as that found in the isomorphous p-nitrophenol complex, and refined by the block-diagonal least-squares method to the final R-values of 0.054 for the N,N-dimethylformamide complex (5151 reflections) and 0.051 for the 2-pyrrolidone complex (5165 reflections). In both complexes, the guest molecules are included in the α-cyclodextrin cavity. The N,N-dimethylformamide molecule is in van der Waals contact with the host α-cyclodextrin molecule, while the 2-pyrrolidone molecule forms a weak N–H…O hydrogen bond with a glycosidic oxygen atom of α-cyclodextrin. The carbonyl oxygen atom of N,N-dimethylformamide and 2-pyrrolidone is hydrogen-bonded to water molecules of hydration located at the primary hydroxyl side of α-cyclodextrin. The tilt-angle of the glucose residue against the plane through six glycosidic oxygen atoms indicates clearly that the macro-cyclic conformation of α-cyclodextrin is affected by the packing as well as the size and shape of the guest molecule. The α-cyclodextrin molecules in the crystal are arranged parallel to the ac plane to form molecular layers. Three water molecules are located near the guest molecule, while the other two water molecules fill the intermolecular space.
Polarized Absorption and Reflection Spectra of the Single Crystals of Benzidine–7,7,8,8-Tetracyano-p-quinodimethane Molecular Complexes
Authors: Yakushi Kyuya , Iguchi Masaaki , Kuroda Haruo 
Published: July 2006

Abstract
Polarized absorption and reflection spectra were observed on the single crystals of the solventfree and solvent containing modifications of benzidine (BD)–7,7,8,8-tetracyano-p-quinodimethane (TCNQ) molecular complex, by using the microspectrophotometers of transmission and reflection types. The absorption spectra obtained by the dispersion analyses of the reflection spectra agreed fairly well with those directly observed by the transmission method. The spectra showed that the BD–TCNQ, complex has non-ionic ground state in all modifications although the intermolecular interaction is considerably strong and is appreciably affected by the inclusion of solvent molecules. In all modifications, the second charge transfer band was confirmed to be polarized in the direction almost perpendicular to the direction of the donor-acceptor stack, while the first charge transfer band is polarized in the direction of the donor-acceptor stack as it is usually found for a typical charge transfer complex. This anomaly of the polarization direction of the second charge-transfer band was concluded to be due to a strong mixing between the charge-transfer excitation and the local excitation associated with TCNQ.
Competitive Redox Reactions at the ZnO Semiconductor Photoelectrode
Authors: Inoue Tooru , Fujishima Akira , Honda Kenichi 
Published: July 2006

Abstract
The study of the photoanodic reaction at the ZnO electrode in an electrolyte solution containing redox agents was carried out by means of the rotating ring-disk electrode technique. The competition reactions between the photocorrosion of ZnO and the oxidation of reducing agents were discussed focusing on the potentials of the electroactive species at the semiconductor-solution interface. The ZnO photoelectrode was stabilized in the course of the oxidation of a strong reducing agent dissolved in a solution.
A Molecular Orbital Calculation of Chemically Interacting Systems. Recombination of Two Methyl Radicals
Authors: Yamabe Shinichi , Minato Tsutomu , Fujimoto Hiroshi , Fukui Kenichi 
Published: July 2006

Abstract
A molecular orbital (MO) approach to a radical-radical reacting system is proposed within the isolated molecule approximation. The interaction energy, ΔW, is defined as the sum of four components, Coulomb, exchange, charge transfer and polarization energies. The four terms are calculated in the recombination of two methyl radicals. The origin of the deformation of methyl radical (D3h→C3v) and the rotational barrier (staggered→eclipsed) in the course of the recombination was found to be the exchange energy caused by the interaction of both doubly occupied MO’s. The difference-density map shows the characteristic role of exchange and charge transfer interactions for charge redistribution.
The Oxidation of Toluene by Cobalt–Copper–Bromide System. A Side-chain Acetoxylation
Authors: Okada Toshihiko , Kamiya Yoshio 
Published: July 2006

Abstract
The liquid-phase oxidation of toluene catalyzed by the cobalt(II) ion and the bromide ion in the presence of the copper(II) ion has been studied. Benzyl acetate was obtained in a good yield (50–70%) with mixed catalysts of metal acetates and sodium bromide in acetic acid at 100–150 °C, accompanied by small amounts of benzaldehyde and benzoic acid. The product distribution was greatly dependent on the NaBr concentration, which can be explained in terms of the high oxidizing ability of the copper(II) ion coordinated by the bromide ion. A synergistic effect was found on the yield of benzyl acetate upon the addition of copper(II) acetate with a high NaBr concentration, the maximum yield being obtained at the Co:Cu:NaBr ratio of 1:1:5–10. A change in the oxygen partial pressure also varied the product distribution, suggesting that the competitive reaction of the copper(II) ion with the oxygen molecule for the benzyl radical was simultaneously taking place at a diffusion-controlled rate. Benzyl acetate was considered to result from the oxidation of the benzyl radical by cop-per(II) bromide and the subsequent solvolysis by acetic acid. The addition of acetic anhydride had a negative effect on the formation of benzyl acetate.
Binary Phase Chlorination of Aromatic Hydrocarbons with Solid Copper(II) Chloride: Reaction Mechanism
Authors: Tanimoto Iwao , Kushioka Keiko , Kitagawa Toyokichi , Maruyama Kazuhiro 
Published: July 2006

Abstract
Anthracene is selectively chlorinated with solid copper(II) chloride to give a quantitative yield of 9-chloroanthracene. The tentative reaction mechanisms so far proposed fail to explain the nonreactivity of some other hydrocarbon homologues, e.g. naphthalene and phenanthrene, toward copper(II) chloride. The present study revealed that the oxidative half-wave potentials (E1⁄2ox) of all reactive hydrocarbon homologues were less than 1.26 V. On the basis of this finding we postulate a reaction mechanism involving one electron transfer from hydrocarbon to copper(II) chloride.
Restricted Rotation Involving the Tetrahedral Carbon. XXVII. Rotamers of 9-(1-Cyano or 1-Methoxycarbonyl-1-methylethyl)triptycene Derivatives Carrying a Substituent in 1-Position
Authors: Otsuka Soichi , Mitsuhashi Tsutomu , \={O}ki Michinori 
Published: July 2006

Abstract
The title compounds were prepared by the reaction between 9-(1-cyano or 1-methoxycarbonyl-1-methylethyl)anthracene and substituted benzynes and their rotational isomers were isolated. The barriers to rotation of these compounds were found to be 35–36 kcal/mol and 32–34 kcal/mol for the processes dl→meso and meso→dl, respectively.
Selective Electrosyntheses on Chemically Modified Electrode. II. Anodic Chlorination of Anisole with Cyclodextrin on Electrode Surfaces and in Solution
Authors: Matsue Tomokazu , Fujihira Masamichi , Osa Tetsuo 
Published: July 2006

Abstract
The anodic chlorination of anisole on an α-cyclodextrin (α-CD) chemically modified electrode via ether linkage (α-CD-CME) and a naked graphite electrode with α-CD or β-CD in solution was studied. In the presence of CD, the p- to o-chloroanisole ratio, formed in the reaction, was higher than that in the absence of CD since o-positions of anisole included in CD are blocked by the inner wall of CD. Especially, α-CD had a profound effect on the p-isomer formation. Increasing the concentration of NaCl added as a supporting electrolyte in the presence of α-CD resulted in a decrease in the ratio because of the inhibition effect of chloride ion on the inclusion of anisole in α-CD, whereas such effect was small in the presence of β-CD. The ratio on α-CD-CME was slightly higher than that on the naked electrode. This indicates that α-CD was introduced on the graphite surface but the surface coverage of α-CD was low, which was in accord with the ESCA results of α-CD-CME.
New Potassium and Ammonium Lead(II) Chromates with a Higher Lead Content and Iso-structural with Potassium Lead(II) Chromate, K2Pb(CrO4)2
Authors: Fukasawa Tsutomu , Iwatsuki Masaaki 
Published: July 2006

Abstract
An unknown yellow precipitate, similar to lead(II) chromate in appearance, has been reported. The precipitate was formed in the detection process of lead(II) ions using chromate ions by a classical qualitative analytical method. The present paper describes the elucidation of the unknown precipitate, and the presence of a series of new chromates iso-structural with the known potassium lead(II) chromate, K2Pb(CrO4)2. The new chromates are explained as new stoichiometric chromates, K4Pb4(CrO4)6 and (NH4)4Pb4(CrO4)6 [=K2Pb2(CrO4)3 and (NH4)2Pb2(CrO4)3], and solid solutions (K, NH4)6−2zPb3+z(CrO4)6 (z=+0.3–+1.2) among the new stoichiometric chromates and the known chromates, K6Pb3(CrO4)6 and (NH4)6Pb3(CrO4)6 [=K2Pb(CrO4)2 and (NH4)2Pb(CrO4)2]. The compositions of the new chromates are dependant on the precipitating conditions. Relationships between compositions, lattice constants, and precipitating conditions are given together with indexed powder diffraction data for references to identification, and the results of thermal analyses.
Asymmetric Benzoin Condensation Catalyzed by Optically Active Thiazolium Salts in Micellar Two-phase Media
Authors: Tagaki Waichiro , Tamura Yoshiharu , Yano Yumihiko 
Published: July 2006

Abstract
Three thiazolium salts, 3-[2-(l-3-p-menthyloxy)ethyl]thiazolium bromide (1), 3-(l-3-p-menthyl)thiazolium halides (2), and 3-(l-3-p-menthyl)-4-methylthiazolium perchlorate (3) have been examined for the catalysis of benzoin condensation in micellar two-phase media. The catalytic activities on the chemical yields of benzoin were observed to be high for 1 and 2 but low for 3. On the contrary, for the asymmetric induction, 3 gave much higher optical purity of 35.3% than in the cases of 1 and 2 (0.8–3.5%). These results are discussed in terms of micellar and conformational effects.
Acidity and Catalytic Activity of Iron(II) Sulfate Heat-treated at High Temperature
Authors: Arata Kazushi , Hino Makoto 
Published: July 2006

Abstract
Acidity and catalytic activity of FeSO4 calcined at 500–900 °C were studied. The product obtained by calcination at 700 °C showed maximum acidity at H0≤1.5 and activity for isomerization of d-limonene oxide, polymerization of isobutyl vinyl ether and dehydration of 2-propanol. When calcined at 750 °C the product showed no acidity or activity.
The Coextraction of Water into Nitrobenzene with Alkali and Alkaline Earth Metal Salts of 2,2′,4,4′,6,6′-Hexanitrodiphenylamine in the Presence of Several Crown Ethers and Cryptands
Authors: Iwachido Tadashi , Minami Masayosi , Kimura Masaho , Sadakane Akira , Kawasaki Mikio , Tôei Kyoji 
Published: July 2006

Abstract
Alkali and alkaline earth metal salts of 2,2′,4,4′,6,6′-hexanitrodiphenylamine (HND) were extracted into nitrobenzene in the absence or presence of several crown ethers or cryptands which differ from one another in hole size. The quantity of water transferred to the nitrobenzene phase was determined by means of the Karl-Fischer method. The NMR and near-infrared spectra show that the coextraction of water is caused by the hydration of the cations. The number of water molecules attached to the cations increases upon going from Cs+ (0.6) to Li+ (5.6) and from Ba2+ (10.5) to Ca2+ (13.0). The complexation between these cations and the crown ethers causes a clear decrease in the hydration number; e.g., in the 1:1 metal–crown ether complexes, more than half of the water molecules are removed, and in the 1:1 metal–cryptand complexes, less than one water molecule remains unremoved. The complexes of a 1:2 stoichiometry are also found; some are stable and carry virtually no water molecules. The number and type of donor atoms have no significant effect on the coextraction of water. The presence of fused benzo rings on the crown ether also has no influence on the number of water molecules.
An ESR Study of N-(Alkylthio)arylaminyls. Substituent Effects on ESR Parameters
Authors: Miura Yozo , Asada Hidetsugu , Kinoshita Masayoshi 
Published: July 2006

Abstract
A series of N-(alkylthio)arylaminyls, ArNSR, were generated by hydrogen-abstraction from N-(alkylthio)anilines or by the photolysis of N,N-bis(t-butylthio)anilines, and were studied by ESR spectroscopy. N-(t-Butylthio)aminyls were fairly long-lived, and their lifetimes were scarcely affected by oxygen. Substituent effects on the ESR parameters were also studied, and the results were compared with those for N-alkoxyarylaminyls.
Bromination of 9-Allyltriptycenes: Bromoolefin Formation and Lifetime of an Intervening Bromonium Ion
Authors: Hatakeyama Shiro , Mitsuhashi Tsutomu , Oki Michinori 
Published: July 2006

Abstract
The bromination of 9-allyl-1,2,3,4-tetrachlorotriptycene affords a mixture of bromoolefins together with a minor quantity of the corresponding dibromide. By the examination of the reactions of model compounds, it is concluded that the first attack of bromine on the olefinic bond takes place in the meso rotamer and the resulted bromonium ion collapses either by attack of the tribromide ion to produce the dibromide or by internal rotation about the C9–Callyl bond followed by attack of the tribromide ion to produce the bromoolefin. Examination of the bromoolefin/dibromide ratios at various temperatures suggests that the activation energy for the attack of the tribromide ion on the bromonium ion is ca. 3 kcal/mol higher than the rotational barrier.
The Low-temperature Photolysis of Diazo Compounds. The Utility of Tertiary Alcohol in Matrix Studies of Carbene Chemistry
Authors: Tomioka Hideo , Miwa Takaaki , Suzuki Shinji , Izawa Yasuji 
Published: July 2006

Abstract
Carbene processes within the t-BuOH matrix at −196 °C were investigated in order to show the utility of the matrix as a tool for the study of carbene chemistry. The photolysis of several aryldiazomethane derivatives in the t-BuOH matrix gave the olefinic dimer as the main product, probably arising from a combination of two triplet arylcarbenes in the aggregate of molecules. The similar photolysis of other diazo compounds (e.g., N2CHCOR, R=OR′, NEt2, and Ph) resulted in no detection of the olefinic dimer. This was explained in terms of the structural effect on the ground-state multiplicity of carbene. The photolysis of Ph2CN2 in t-BuOH containing 5% EtOH at −196 °C gave almost exclusively O–H and C–H insertion products with the solute alcohol at the expense of the O–H insertion product with the host, i.e., Ph2CHOBut, which was the major product in the liquidphase photolysis. This is ascribable to the co-aggregation of the carbene precursor with the solute alcohol because of the relatively large guest hole provided by the bulky tertiary alcohol matrix. A more general utility of this matrix was shown in the reaction of Ph2C with Ph2CO to give oxirane, in which the intervention of carbonyl ylide was demonstrated at low temperatures.
Calculations of g Tensors and Hyperfine Splitting Tensors for Molecules in Their Triplet States
Authors: Morikawa Tetsuo , I’Haya Yasumasa J , Nakano Junji 
Published: July 2006

Abstract
The g tensors and hyperfine splitting (hfs) tensors of simple organic radicals in their triplet states have been calculated by using an all valence electron SCF MO method with a first order perturbation treatment. The molecular orbital spin density is partitioned into the σ- and π-electron spin delocalization (SD) terms and the rest terms of spin polarization (SP) which arise from the CI effect. The g tensors for CH2 and several other carbenes which have triplet ground states and for formaldehyde in its nπ* and nσ* excited triplet states are evaluated. The calculated α-proton hfs constants of CH2 contributing from the π orbital well compare with the observed hfs constants of the triplet naphthalene and the doublet malonic acid radical. The anisotropic carbon-13 hfs constants of CH2 are determined almost completely by the SD contribution and their absolute values are in good accord with those observed for CD2. Contribution of the SP terms to the isotropic hfs constant is found to be fairly large. Prediction of the hfs constants in CF2 and CHF is made.
Conformations of Acetanilide and Related Compounds Studied by Ultraviolet Photoelectron Spectroscopy
Authors: Nakagaki Ryoichi , Kobayashi Tsunetoshi , Nagakura Saburo 
Published: July 2006

Abstract
Conformations of acetanilides were studied by UPS in the vapour phase. The dihedral angle, θ, between the amide group and the phenyl group was evaluated from the difference in the vertical ionization energy, ΔEiv, between the two MO’s, the anti-bonding and bonding type combinations of the benzene ring e1g(S) orbital and the highest occupied π orbital of the amide group. The steric inhibition of conjugation due to N-methylation is larger than that due to ortho-methylation. For this series of compounds, ΔEiv is directly proportional to cos θ and this simple relationship is useful for the rough estimation of θ.
SORPTION OF GAS BY MINERAL. III. SILICIC ACID MINERALS
Authors: Sameshima Jitsusaburo 
Published: July 2006

Abstract
1. Sorption of ammonia by dehydrated materials of chalcedonies, opal, diatomaceous earth, natural silica gels and siliceous sinter have been measured.
2. All these substances sorb considerable amounts of ammonia at ordinary temperature.
3. The sorption velocity can be expressed by the equation
x=Klogt+k,
where x is the sorption amount at time t, and K and k are the constants.
ON THE UNSAPONIFIABLE MATTER OF CALAMARY OIL
Authors: Tsujimoto Mitsumaru 
Published: July 2006

Abstract
(1) The unsaponifiable matter of calamary oil contained 48% of cholesterol.
(2) Besides cholesterol, the presence -of cetyl, batyl and selachyl alcohols has been confirmed. Oleyl and chimyl alcohols were probably present. A small amount of the alcohols of higher unsaturation appeared also to be present.
(3) The occurrence of the alcohols of the selachyl alcohol group (monoglyceryl ethers) in calamary oil indicates the wide distribution and vital importance of these compounds as constituents of liver oils of various marine animals.