bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dye Sensitized Photo-oxidation of Diphenylamine
Authors: Bansal W R , Puri S , Sidhu K S 
Published: July 2006

Abstract
Evidence is presented to show that excited O2(1∑g+, 1Δg) is an intermediate in the dye (methylene blue, rose bengal, eosin) sensitized oxidation of diphenylamine which yeilds N-phenyl-p-benzoquinonimine. The relative rates in different solvents are reported and a mechanism is suggested.
The Decomposition of Nitrous Oxide in the Radiolysis of n-Hexane Solutions
Authors: Hatano Yoshihiko , Abboud José-Luis 
Published: July 2006

Abstract
The effect of the addition of N2O (10−2−10−4 mole fraction) in the radiolysis of liquid n-hexane has been examined. The oxygen-contaning products such as water and alcohols have been detected. The number of nitrogen molecules products per an electrons scavenged by N2O exceeds unity even at the lowest concentration.
Reactivity of exo- and endo-Tricyclo[3.2.1.02,4]octan-8-ylidenes and 7-Norbornenylidene
Authors: Murahashi Shun-ichi , Okumura Kazuo , Maeda Yusuke , Sonoda Akio , Moritani Ichiro 
Published: July 2006

Abstract
endo-Tricyclo[3.2.1.02,4]octan-8-ylidene (2) generated by the thermolysis of sodium salt of endo-tricyclo[3.2.1.02,4]octan-8-one tosylhydrazone (5) gave toluene (3.9%), cyclohepta-1,4-diene(6, 14%), cyclohepta-1,3-diene(7, 3.5%), bicyclo[3.3.0]octa-1,6-diene(8, 4.8%), bicyclo[3.3.0]octa-1,7-diene(9, 9.0%), and endo-tricyclo[3.2.1.02,4]octane (10, 21%). In sharp contrast, exo-tricyclo[3.2.1.02,4]oct-8-ylidene (1) gave toluene (1.5%) and tricyclo[5.1.01,7]oct-5-ene (14, 57%). The results indicate significant homoconjugative interaction between the p-orbital of the divalent carbon and the symmetric Walsh orbital of the cyclopropane. This is in line with the results of 7-norbornenylidene (3) in which the interaction between the divalent carbon and the carbon-carbon double bond stabilizes the nonclassical methylene. Thermolysis of sodium salt of 7-norbornenone tosylhydrazone (18) gave rise to cyclohexa-1,3-diene (3%), norbornene (6%), toluene (5%), spiro[2.4]hepta-4,6-diene (19, 10%), and bicyclo[3.2.0]hepta-1,6-diene (21, 56%).
An Inversion of Configuration of Threonine and Allothreonine in the N,O-Acyl Migration Reaction with Concentrated Sulfuric Acid
Authors: Wakamiya Tateaki , Tarumi Yuzo , Shiba Tetsuo 
Published: July 2006

Abstract
On the N,O-acyl migration reaction of β-hydroxy-α-amino acids with concentrated sulfuric acid, a configuration of the carbon atom carrying hydroxyl group was found to be inverted through the reaction. Thus, threonine residue in peptide was converted to allothreonine residue and vice versa in the selective chemical cleavage of threonine peptide employing the N,O-migration with concentrated sulfuric acid. The reaction mechanism involving SNi elimination of O-sulfate formed as an intermediate was suggested. The inversion did not occur in the N,O-acyl migration reaction with other mineral acids than sulfuric acid.
Studies of the Reactions of Amines with Sulfur Trioxide. IV. One-step Synthesis of N-substituted Imidobissulfates from Amines
Authors: Kanetani Fujio , Yamaguchi Hachiro 
Published: July 2006

Abstract
The scope and limitations of a one-step synthesis of N-substituted imidobissulfates, RN(SO3K)2 (R=Me, Et, n-Pr, iso-Pr, n-Bu, iso-Bu, sec-Bu, tert-Bu, n-C6H13, cyclo-C6H11, PhCH2–, PhCH2CH2–, PhCH(CH3)–, or Ph), starting from amines and the sulfur trioxide-triethylamine complex are described. The yields are generally good (55–90%). However, with aniline only a poor (13%) yield was obtained. With tert-butylamine, tert-butylamidosulfate was obtained quantitatively instead of the expected tert-butylimidobissulfate. Bis(cyclohexylammonium) salts of the imidobis(sulfuric) acids are prepared, and their properties are briefly recorded.
The Reactions of β-Hydroxychalcones and 2-Acetoxy-1,3-diarylpropan-1,3-diones with Lead Tetraacetate
Authors: Kurosawa Kazu , Moriyama Akira 
Published: July 2006

Abstract
The reaction of β-hydroxychalcone with lead tetraacetate gave benzil. The reaction of 4,4′-dimethoxy-β-hydroxychalcone gave 2-acetoxy-1,3-di(p-methoxyphenyl)propan-1,3-dione and 4,4′-dimethoxybenzil. The reactions of 2-acetoxy-1,3-diarylpropan-1,3-diones yielded 2,2-diacetoxy-1,3-diarylpropan-1,3-diones and benzils respectively. The formation of the benzils from β-hydroxychalcones and 2-acetoxy-1,3-diarylpropan-1,3-diones has been shown to involve 1,2-aryl and 1,2-aroyl migration respectively by studies of the oxidations of 14C-labelled compounds.
Photochemistry in Micellar System. I. Stabilization of the Radical Anions of Anthraquinonesulfonates
Authors: Kano Koji , Matsuo Taku 
Published: July 2006

Abstract
Micellar effects on the photochemical reactions of sodium 9,10-anthraquinone-2-sulfonate and disodium 9,10-anthraquinone-2,6-disulfonate were studied by means of ESR and electronic spectroscopy. In the presence of anionic and non-ionic surfactants, irradiation of the quinones in aerobic phosphate buffer (pH 8.0) gave the corresponding radical anions, which were incredibly long-living (over several weeks) as compared with irradiation without surfactant. Plausible mechanisms of the micellar effects on the stabilization of the radical anions are discussed.
Charge-transfer and Proton-transfer in the Formation of Molecular Complexes. X. Picric Acid Complexes with 2,5-Dichloroaniline
Authors: Matsunaga Yoshio , Saito Gunzi , Sakai Naoto 
Published: July 2006

Abstract
Yellow 2,5-dichloroanilinium picrate was found to isomerize into a red complex of the charge-transfer type at 74 °C with a heat of transition of 4.2 kcal/mol. In addition, a charge-transfer complex with a 1 : 3 mole ratio was isolated.
Experimental Determination of Ionization Potentials of Organic Amines, β-Carotene and Chlorophyll a
Authors: Nakato Yoshihiro , Chiyoda Takeshi , Tsubomura Hiroshi 
Published: July 2006

Abstract
Ionization potentials (Ip’s) of several organic compounds have been determined by the method of photocurrent measurements in gas and organic solvents. It has been found that the vapor-phase Ip’s, calculated from those determined from the onsets of the photo-currents in solutions by using Born equation for the solvation energies of the cations and a common term for the energy of the electron in solution, agree well with those measured in the vapor phase. Based on this result, the Ip’s of molecules in the gas phase can be derived from those measured in the solution. This method is useful for the determination of Ip’s of large molecules which cannot be obtained in the gas phase. Some of the Ip’s obtained are: 5.6 for 1,1,4,4-tetrakis(dimethylamino)butadiene, 5.7 for 3,3′-dimethyl-2,2′-bibenzothiazolinylidene, 6.4 for β-carotene, 6.1 for chlorophyll a, 6.3 for dihydridobis(π-cyclopentadienyl)tungsten (eV unit). The conditions of lowering the Ip’s of organic molecules are discussed.
Derivatives of l,2-Dithiole-3-thiones. VII. Study of Reaction of Thiocarbonyl S-Imide with Amines
Authors: Tamagaki Seizo , Sakaki Keishi , Oae Shigeru 
Published: July 2006

Abstract
Thiocarbonyl S-imide of 4,5-benzo-1,2-dithiole-3-thione reacted with primary and secondary amines of various types to give both rearranged and amine-exchanged imines. By kinetical studies a plausible mechanism involving the addition and elimination of amine on the tetravalent sulfur atom was proposed.
Restricted Rotation Involving the Tetrahedral Carbon. XI. Barriers to Rotation and Conformational Preferences of Substituted 9-Isopropyltriptycenes
Authors: Suzuki Fumio , Oki Michinori , Nakanishi Hiroshi 
Published: July 2006

Abstract
Several 9-isopropyltriptycene derivatives were prepared by addition of benzynes to 9-isopropylanthracenes. Rotation about the C9-Cpr bond of these compounds is found to be frozen at room temperature on the NMR time scale. Those compounds which carry a substituent at 1-position exist as dl-isomers, at least overwhelmingly. No sign of existence of meso-isomer is found. On the other hand, 9-isopropyl-2,4-dimethyltriptycene exists as a mixture of d, l, and meso isomers, composition of which is almost 1 : 1 : 1. Repulsive nonbonding interaction is a decisive factor to determine the conformational preference. Approximate methods for line shape analysis of two methyl groups in an isopropyl group are discussed. Activation energies for rotation about the C9-Cpr bond increase with the increase in the size of 1-substituent except for the methyl group. The smaller effective size of the methyl group than that expected from the van der Waals radius is attributed to cogwheeling arrangement of methyl and isopropyl groups at the transition state of rotation and/or the higher energy level of the ground state due to the severe interaction between methyl and isopropyl groups.
Reaction of 1-Methyl-4-phenylquinazolinium Salts with Diazomethane
Authors: Yamada Yoshihisa , Oine Toyonari , Inoue Ichizo 
Published: July 2006

Abstract
For the synthesis of 5-phenyl-1,4-benzodiazepines, reaction of quinazolinium salts with diazomethane was studied. In the course of the study, it was found by NMR spectroscopy that the starting materials (2) reacted even with a slight amount of water present in the solvent to give hydrates 5. Treatment of 2c with diazomethane at 10 °C under absolute anhydrous conditions gave quinazoline 8c and benzodiazepines 9 and 10c in about the same ratio. In the reactions at lower temperatures, the distribution of the products varied markedly, and the ring expansion product 10c was obtained in an improved yield. The mechanism for the formation of 8, 9, and 10 was discussed.
Chemical Behavior of Intermediates Produced in Sulfuric Acid Glass by Gamma Irradiation. I. Reactivities of Mobile Electrons with Inorganic Ions
Authors: Sasaki Teikichi 
Published: July 2006

Abstract
The yield of the trapped hydrogen atom, Ht, produced in the 6 M sulfuric acid matrix at 77 K was decreased by the presence of an electron scavenger. Based on the competition reaction kinetics, the reactivities of mobile electrons, em−, with metallic and oxygen-containing ions were determined from the decrease in the Ht yield. It was found that em− is scavenged most efficiently with the TeO42− ion. The relative reaction rates of em− with oxyanions were generally larger than those of the corresponding eaq− reactions. On the other hand, a good accordance in the reaction rates for both forms of electrons was observed in the cases of the reactions with metallic ions. An interpretation was given to the discrepancy in the observed reaction rates that em− in the epithermal energy region goes over the Coulomb barrier, which is too high for eaq− to pass through, and thus reacts more efficiently with anionic species than does eaq−. Some unstable intermediates produced at 77 K polymerized with the solute during the thermal annealing. The ESR and optical spectra of the polymerized cadmium and molybdenum are shown, together with those of the primarily-produced species.
Proton Nuclear Magnetic Resonance Spectroscopy of Partially-deuterated n-Pentanes
Authors: Kondo Masahiro , Ando Isao , Chûjô Riichirô , Nishioka Atsuo 
Published: July 2006

Abstract
The proton NMR spectra of some partially deuterated n-pentanes were observed under both proton-deuteron (H–D) spin-coupled and -decoupled conditions. With using the spectrum-simulation method, it was confirmed experimentally that the chemical shift of the CH2(3) protons appears at a higher field than that of the CH2(2) protons.
Phase Equilibria of the Systems Containing Silver Iodide and Alkali Iodide. II. AgI–NaI–H2O System
Authors: Nishimura Norio , Higashiyama Tatsuo 
Published: July 2006

Abstract
Phase diagrams were constructed for the equilibria of the AgI–NaI–H2O system at temperatures 0–70 °C. A compound AgI·NaI·3H2O was isolated, and the compound was found by means of X-ray analysis to belong to the orthorhombic system with cell constants a=8.78, b=33.5, and c=6.48 Å.
The Cyclopolymerization of Triallyl Citrate
Authors: Matsumoto Akira , Ohata Tetsuji , Oiwa Masayoshi 
Published: July 2006

Abstract
The radical polymerization of triallyl citrate was carried out at 60 °C, benzoyl peroxide being used as the initiator and benzene as the solvent; here it has been considered kinetically in terms of cyclopolymerization. Thus, the kinetic equations for the polymerization of the triallyl ester were first derived by an extension of the kinetic treatment for the cyclopolymerization of the diallyl ester. Next, they were applied to the polymerization of triallyl citrate. In consequence, the following results were obtained: (i) the rate of polymerization, Rp, was not proportional to either the square root or first power of the initiator concentration, [I]; rather, Rp/[I]1⁄2 and [I]1⁄2had a linear relationship, (ii) the relation between the rate of polymerization over the degree of polymerization, Rp/\barPn,o, and the monomer concentration, [M], was also linear, and (iii) the ratio of the unimolecular cyclization reaction to the bimolecular propagation reaction of the uncyclized radical, Kc, was estimated to be 4.5 mol/1 from the dependence of the residual unsaturation on the monomer concentration.
Bromine Addition to Chloronorbornene Derivatives
Authors: Yanagida Y\={u}ji , Shigesato Hideo , Nomura Masakatsu , Kikkawa Sh\={o}ichi 
Published: July 2006

Abstract
The reaction of bromine with both trans-5,6-dichloro-2-norbornene (I) and exo-cis-5,6-dichloro-2-norbornene (III) in an acetic acid solution gave trans-adducts in a 100% yield, while the bromination of endo-cisr-5,6-dichloronorbornene (II) afforded the endo-cis adduct in a ca. 100% yield. The latter observation was explained in terms of a sterical inhibition of the bromide ion’s attack in the endo-direction by the two endo-chloro substituents. In the CCl4 solution, however the reaction of I with bromine afforded the exo-cis adduct in a 64% yield, together with the trans-adduct (36% yield). Then, the reaction of I with bromine was carried out in several other solvents (CH3OH, Cl(CH2)2Cl, CH3CO2C2H5, and CCl4). As the polarity of the solvents (the ET values are used here as a measure of the solvents’ polarity) decreased, the formation of the exo-cis adduct became progressively more predominant, while the addition of bromide salt retarded the formation of the exo-cis adduct. Such results and the kinetic studies suggested that the exo-cis adduct was formed through the carbonium bromide ion-pair mechanism. The stereoisomers obtained in this study were assigned on the basis of the NMR spectra.
The Magnetic Circular Dichroism of Some Copper(II) β-Diketone Chelate Complexes in Various Media
Authors: Katô Hajime , Kimura Takahide 
Published: July 2006

Abstract
The magnetic circular dichroism (MCD) and absorption spectra of Cu(acac)2, Cu(bzac)2, Cu(TFacac)2, and Cu(TFacac)2 in benzene, chloroform, methylene chloride, 1,4-dioxane, pyridine, and piperidine are observed. The behavior of these spectra can be well explained by proposing this order of energy levels: dxz, dyz&lt;dx2−y2&lt;dz2&lt;dxy. The MCD spectra in pyridine do not show any dispersion in the neighbourhood of the absorption peak which seems to correspond to the dxz, dyz→dxy transition; this fact suggests that the B-term of the MCD parameters is dominant at room temperature. There is no serious difference between the MCD of Cu(acac)2 and Cu(bzac)2, or between Cu(HFacac)2 and Cu(TFacac)2. It appears that this lowering of symmetry is not important in interpreting the MCD spectra.
Crystal and Molecular Structure of (−)-erythro-1′-(2,5-Dimethoxyphenyl)-3′-diethylaminobutyl Acetate Hydrobromide
Authors: Masuda Yoshihiro , Iitaka Yoichi , Hamano Hiroaki 
Published: July 2006

Abstract
In order to determine the stereospecificity and absolute configuration of 1′-(2,5-dimethoxyphenyl)-3′-diethylamino-n-butanol, X-ray structure analysis of its acetate hydrobromide has been carried out. The crystal of the derivative belongs to the monoclinic space group C2, with lattice constants a=14.218, b=8.290, c=18.187Å, β=108.1°, containing four formula units of C18H29O4N·HBr in a unit cell. The structure was solved by the heavy atom method and refined by the block-matrix least squares method to an R value of 0.06. The absolute configuration was determined by the use of the anomalous dispersion method, the configuration at the two asymmetric carbon atoms being found to be S.
Novel Radical Salt Polymers as Hydrogenation Catalyst of α-Olefins
Authors: Kawazura Hiroshi , Yamamoto Yoshiro , Ohmori Toshio , Murano Kentaro , Inokuchi Hiroo 
Published: July 2006

Abstract
Novel polymeric radical salts prepared by inserting alkali-metals into semi-conductive polymers derived from poly(tetrahalophenylene sulfides) were found to be effective hydrogenation catalyst for α-olefins; their activity trends as to the sort of alkali-metal and halogen of the matrix polymer were Cs&gt;K&gt;Na and F&gt;Cl&gt;Br respectively. The catalyst also showed an activity for the cis-trans isomerization of hex-2-ene which was proportional to that for the hydrogenation. The activities of the catalyst were discussed in terms of its steric confinement.
The Structure of Ternstroemiaxanthin, a New Aldehydic C40-Carotenoid
Authors: Kikuchi Kiyoshi , Yamaguchi Masaru 
Published: July 2006

Abstract
A new carotenoid, ternstroemiaxanthin, was isolated as a main constituent from the red seeds of “Ternstroemia japonica,” and the structure of the pigment was determined to be 3-hydroxy-β,ψ-caroten-18′-al (I) by spectral and chemical methods.
Reactions of 2-Cyano-2-dimethylamino-1,3-dithiolane
Authors: Hiratani Kazuhisa , Nakai Takeshi , Okawara Makoto 
Published: July 2006

Abstract
The reactions of 2-cyano-2-dimethylamino-1,3-dithiolane (2) with electrophiles (organic halides and perchloric acid) and nucleophiles were investigated. It was found that 2 dissociated partially to 2-dimethylamino-1,3-dithiolan-2-ylium (1) and cyanide ions in polar solvents. In the reactions of 2 with electrophiles, nitriles were obtained along with the formation of salts of 1. The reactions of 2 with nucleophiles were studied since 2 was expected to be a precursor of the cation 1. In some cases, its reactivity differs from that of perchlorate of 1. A mechanism was discussed in which the cyanide ion might behave as a base to abstract a proton from the nucleophiles.
The Cyclocopolymerization of Triallyl Citrate with Several Vinyl Monomers
Authors: Ohata Tetsuji , Matsumoto Akira , Oiwa Masayoshi 
Published: July 2006

Abstract
Triallyl citrate (TAC) was copolymerized with allyl benzoate (ABz), vinyl acetate (VAc), vinyl chloride (VC), acrylonitrile (AN), and styrene (St) at 60°C with benzoyl peroxide or 2,2′,-azobisisobutyronitrile as the initiator; it was considered kinetically in terms of cyclocopolymerization. The following monomer reactivity ratios were obtained: VAc: r1=1.29, r2=0.76, rc=0.61; ABz: r1=1.63, r2=1.10, rc=0.47; VC: r1=0.40; r2=1.90, rc=0.31; AN: r1=0.01, r2=8.7; St: r1=0.03, r2=53.0, where r1, rc and r2 denote the monomer reactivity ratio of the uncyclized, cyclized, and monovinyl radicals respectively. In the copolymerization of TAC with AN, the penultimate effect was also observed: r1=r1′=0.01, r2=k122⁄k121=11, r2′=k222⁄k221=5.
Emission Spectra of Carbon Disulfide, Hydrogen Sulfide, and Thiols by Controlled Electron Impact
Authors: Toyoda Minoru , Ogawa Teiichiro , Ishibashi Nobuhiko 
Published: July 2006

Abstract
The emission spectra in the 200–600 nm region produced by the controlled electron impact method were investigated in the vapor phase on hydrogen sulfide, carbon disulfide, methanethiol, and ethanethiol at low pressures. The photoemissions were observed and assigned for an excited parent molecule, molecular ions, and fragments, such as CS2, CS2+, H2S+, H, CH, CS, and HS+. The intensities of the photoemission of most of the species were found to increase linearly with both the electron beam current and the gas pressure, and these species were concluded to be produced in some one-electron unimolecular processes.
The Derivation of the rs Structure by the Use of a Nondiagonal Weight Matrix for Rotational Constants
Authors: Hirose Chiaki 
Published: July 2006

Abstract
The use of a nondiagonal weight matrix in a least-squares analysis of the quantities which themselves are derived from another least-squares analysis is discussed in relation to the analysis of rotational constants in determining molecular geometry. The method is applied to the calculation of the rs structure of ethylene oxide, and the result is compared with those obtained by Kraitchman’s formula and by a least-squares fit by the use of a diagonal weight matrix.
Solution Properties of Phycocyanin. II. Studies of the Molecular Shape and Size by Using the Shell Model
Authors: Kotera Akira , Saito Takahide , Iso Naomichi , Mizuno Haruo , Taki Nobuo 
Published: July 2006

Abstract
The number-average molecular weight and intrinsic viscosity of phycocyanin, isolated from Porphyra tenera, have been determined by osmotic pressure and viscosity measurements at various values of pH and ionic strength. The molecular shape and size for phycocyanin aggregates were also discussed by comparing the experimental values of sedimentation coefficient and intrinsic viscosity with the calculated results obtained by using the shell model theory. It is shown that the aggregate of phycocyanin at pH 5.4 is a hexamer of molecular weight 256000 and the structure consists of six juxtaposed monomers. The monomer is a prolate ellipsoid of 35 Å in diameter and 105 Å length. This structure for the hexamer is consistent with the model proposed by Jennings. At pH 6.8, it is shown that the number-average molecular weight of phycocyanin depends on the ionic strength in solution.
A Semi-empirical Calculation of the Substituent Effects on 1H Chemical Shifts in Aromatic Side-chains
Authors: Niwa Jun 
Published: July 2006

Abstract
The diamagnetic contribution of the hydrogen atom, in the C–H bond and that from its bonded carbon have been semi-empirically expressed. By considering the “ring-current” effect in addition to such contributions, a semi-empirical expression has been obtained for 1H chemical shifts relative to the unsubstituted compound in substituted aromatic side-chains. The applicability of the expression has been examined for m- and p-substituted phenylacetylenes, styrenes, toluenes, and benzaldehydes.
Substitution and Hydrogen Bonding Effects on Fluorescence and Intersystem Crossing in Naphthaldehydes and Their Derivatives
Authors: Kitamura Michio , Baba Hiroaki 
Published: July 2006

Abstract
Absorption and fluorescence spectra, fluorescence and phosphorescence quantum yields and lifetimes of 1-and 2-naphthaldehyde and their derivatives have been measured in rigid glass solution at 77 K. Naphthaldehydes and acetonaphthones are non-fluorescent, whereas naphthoyl chlorides and methyl naphthoates are fluorescent. Upon formation of a hydrogen bond with ethyl alcohol, 2-naphthaldehyde and 2-acetonaphthone become fluorescent, and 1-naphthoyl chloride increases in fluorescence quantum yield by a factor of about 65. The rate constants for intersystem crossing in these three molecules decrease by about two orders of magnitudes as a result of hydrogen bonding. The decrease of the rate constants is attributed to elevation of the (n, π*) level and the resulting change in its position relative to the (n, π*) level. The experimental results are discussed in relation to the current theories of radiationless transition, and are found to conform to the theory in which both spin-orbit coupling and nuclear kinetic-energy operators are treated as the perturbation causing intersystem crossing.
Normal and Reverse Photochromism of 1-(β-carboxyethyl)-3,3-dimethyl-6′-nitrospiro[indoline-2,2′-2H-benzopyran] in Water–Dioxane
Authors: Namba Kenryo , Suzuki Shuichi 
Published: July 2006

Abstract
The photochromism of 1-(β-carboxyethyl)-3,3-dimethyl-6′-nitrospiro[indoline-2,2′-2H-benzopyran] (I) was studied in water-dioxane. It was found that (I) exhibits normal photochromism in dioxane and reverse photochromism on addition of water to the solution.