bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Reaction of Singlet Methylene with Methane
Authors: Shibuya Kazuhiko , Obi Kin-ichi , Tanaka Ikuzo 
Published: July 2006

Abstract
Cyclopropane in an excess of methane was photolyzed at 1470 and 1634 Å. The decomposition rate constants of the resultant vibrationally excited ethane into methyl radicals were found to be 6.0×109 s−1 and 5.0×109 s−1 at 1470 and 1634 Å respectively. The following procedure was used in treating the results obtained in our and the other researchers’ systems. The statistical calculation was made to estimate the internal energy of singlet methylene, \barεi which is initially acquired in the primary decomposition process. The RRKM theory was then used to estimate the internal energy of the excited ethane. According to these calculations, the fraction of excess photon energy carried into ethane decreases as the energy, \barεi increases.
An External Heavy Atom Effect upon the Photoreaction of N-Acetyldiphenylmethyleneamine in Toluene
Authors: Asao Shuichiro , Toshima Naoki , Hirai Hidefumi 
Published: July 2006

Abstract
The photochemical conversion of N-acetyldiphenylmethyleneamine (I) in toluene to produce an addition product N-(1,1,2-triphenylethyl)acetamide and a hydrogenation product N-(diphenylmethyl)acetamide has been found to increase remarkably by displacement of para-hydrogen of toluene with a halogen (chlorine or bromine). A number of halogenated solvents, especially brominated solvents such as dibromomethane and bromobenzene, also promoted the photoreaction of the imine I with toluene. The extent of the promotion depends on the kind of a halogen atom of the solvent molecule. The reaction rate was accelerated with the number of halogen atoms of the solvent molecule. The conversion rate increased very remarkably when the concentration of bromobenzene increased from 0 to 1 mol/l. The reaction via chemical sensitization by benzophenone, a contaminant in imine I, was shown to be insensitive to the heavy atom solvent. The heavy atom effect can be attributed to an increase in the rate of intersystem crossing from the excited singlet state to the triplet state of the imine I. Imine I in the excited state was confirmed to have a hydrogen abstracting character.
Solid Phase Peptide Synthesis by Oxidation-Reduction Condensation. Synthesis of Adrenocorticotropin(1–24) by Chain Elongation at the Carboxyl End on Solid Support
Authors: Maruyama Hiroshi , Matsueda Rei , Kitazawa Eiichi , Takahagi Hidekuni , Mukaiyama Teruaki 
Published: July 2006

Abstract
Solid phase peptide synthesis by oxidation-reduction condensation via fragment condensation at the carboxyl end was established by a new monitoring method based on high pressure liquid chromatography. The merit of the method was demonstrated through the synthesis of ACTH (1–24). A resin–tetracosapeptide with quantitative amino acid ratios was easily prepared by coupling 6 fragments of 1–2, 3–7, 8–10, 11–14, 15–19, and 20–24 sequences. ACTH (1–24) with a full activity was obtained in 25% yield from the initial resin-dipeptide by hydrogen fluoride treatment and purification with carboxymethyl-cellulose chromatography.
The Kinetics of the Reaction between the Chromium(III) Ion and the Ethylenediamine-N,N,N′,N′-tetraacetate Ion in the Presence of Hydrogen Peroxide
Authors: Yamamoto Katsumi , Ohashi Kousaburo 
Published: July 2006

Abstract
The rate of the reaction between chromium(III) ion and ethylenediamine-N,N,N′,N′-tetraacetate was found to be accelerated upon the addition of a large excess of hydrogen peroxide. Under such a condition the rate of CrIII(edta)(H2O)− formation shows a first-order dependence on the concentrations of hydrogen peroxide and chromium(III) ions, but is independent of the concentration of EDTA. The rate of CrIII(edta)(H2O)− formation catalyzed by the hydrogen peroxide increases with an increase in the pH and decreases with an increase in the acetate ion concentration. The kinetic study suggested that the initiation of the reaction takes place as follows: Cr(III)+H2O2→Cr(IV)+OH·+OH− The reaction mechanism of the hydrogen-peroxide catalysis is discussed in terms of the formation of the chromium(IV)– and /or the chronium(V)–EDTA complex in the course of the reaction. It was found that monohydroxochromium(III) is much more reactive than the chromium(III) ion toward hydrogen peroxide.
The Mechanism of the Hydrolysis of Condensed Phosphates. IV. The Hydrolysis of Pyro-, Tripoly-, Trimeta-, and Tetrametaphosphates in Aqueous Organic Solvents
Authors: Watanabe Makoto , Sato Shoji , Saito Hajime 
Published: July 2006

Abstract
The hydrolysis of sodium pyro-, tripoly-, trimeta-, and tetrametaphosphates was run in water, aqueous ethanol, aqueous glycerol, aqueous acetonitrile, aqueous dimethyl sulfoxide, and aqueous tetrahydrofuran at various pH values and temperatures. The initial concentration of the phosphates was 0.025 mol/l. The hydrolysis of the poly- and metaphosphates followed first-order kinetics with respect to the concentration of the phosphate, under all conditions studied. The hydrolysis of sodium pyro- and tripolyphosphates was an acid-catalyzed reaction and that of sodium trimeta- and tetrametaphosphates was an acid- and base-catalyzed reaction. In acidic solutions, the rate of hydrolysis of the poly- and metaphosphates in water was slower than that in any aqueous organic solution. It is concluded that the nucleophilicity of the water molecule in the aqueous organic solutions may increase on account of the interaction of the water molecule with the organic molecules. The hydrolysis of sodium pyro-, tripoly-, trimeta-, and tetrametaphosphates in acidic solutions is considered to be of the SN2 type, because the overall-reaction rate is highly dependent on the nucleophilicity of the water molecule. The solvent effect on the rate of hydrolysis of sodium tripolyphosphate in basic solutions was the same as that in acidic solutions and hence the mechanism of the hydrolysis of sodium tripolyphosphate in basic solutions may be the same as that in acidic solutions. The rate of hydrolysis of sodium trimeta- and tetrametaphosphates in a basic water solvent was much faster than that in basic aqueous ethanol and basic aqueous dimethyl sulfoxide and was largely slower than that in basic aqueous glycerol. Consequently, the mechanism of the hydrolysis of sodium trimeta- and tetrametaphosphates in basic solutions seems to differ from that in acidic solutions. The acceleration of the rate of hydrolysis of the metaphosphates by the organic molecules depends significantly upon the activation energy. The activation energy of the hydrolysis of sodium pyro-, tripoly-, trimeta-, and tetrametaphosphates was 17–34 kcal/mol in the pH range of 1.0–12.2 and increased with an increase in the pH value of the phosphate solution in water and aqueous ethyl alcohol solventss.
Studies on Leuckart-Wallach Reaction Paths
Authors: Ito Keiichi , Oba Hitoshi , Sekiya Minoru 
Published: July 2006

Abstract
The Leuckart-Wallach reaction paths were investigated by means of catalytic reduction in the Leuckart-Wallach reaction system and on the basis of analogous formic acid reductions. It was determined that, in the early stage of the Leuckart-Wallach reaction, ammonia, amine and also formamide undergo addition reactions to carbonyl compounds. The addition of formamide catalyzed by formic acid plays a significant role only for the more reactive substrates such as benzaldehyde. The behaviors of plausible intermediates for the formic acid reduction are discussed on the basis of the data of similar formic acid reductions.
Synthesis of 2,7-Di-t-butyl-4,5,9,10-tetraphenyltricyclo[6.2.0.03,6]deca-1,3(6),4,7,9-pentaene. A Benzo[1,2: 4,5]dicyclobutene
Authors: Toda Fumio , Takahara Yutaka 
Published: July 2006

Abstract
The title compound (15) which has two cyclobutadienes fused to a benzene ring, was synthesized by heating dl- (7), meso-3,8-di-t-butyl-1,5,6,10-tetraphenyldeca-3,4,6,7-tetraene-1,9-diyne (8), or E,Z,-3,4-bis (1-t-butyl-3-phenyl-2-propynylidene)-1,2-diphenyl-1-cyclobutene (12).
Synthesis and Properties of Organocobalt(III)octaethylporphyrins
Authors: Ogoshi Hisanobu , Watanabe Ei-ichi , Koketsu Norihisa , Yoshida Zen-ichi 
Published: July 2006

Abstract
The syntheses of alkylcobalt(III)octaethylporphyrins(OEP) via nucleophilic attack of the Co(I) complex to unsaturated compounds are reported. Olefins with an electron-withdrawing group and acetylenes react with Co(I)(OEP), whereas olefins with an electron-donating group such as propylene and cyclohexene are unreactive. A novel ring cleavage of cyclopropyl methy ketone initiated by Co(I)(OEP) affords alkylCo(III)(OEP). The reduction of cobalt(II) N-methyloctaethylporphyrin acetate results in intramolecular methyl migration from nitrogen to the central cobalt atom. Five-coordination has been established for the organocobalt(III)(OEP) complexes on the basis of their analytical, infrared and NMR data. Some anomalous behavior of the proton signals of the α-carbon atom in their NMR spectra has been discussed in terms of quadrupolar relaxation and electronegativity of the cobalt ion.
Reactions of Dihydridotetrakis(triphenylphosphine)ruthenium(II) with Olefins and Isolation of New Ruthenium–Olefin Complexes
Authors: Komiya Sanshiro , Yamamoto Akio 
Published: July 2006

Abstract
Dihydridotetrakis(triphenylphosphine)ruthenium(II), RuH2(PPh3)4, reacts with olefins (ethylene, propylene, styrene and butadiene) to give olefin-coordinated complexes of the type, Ru(olefin)(PPh3)3 and equimolar amounts of their hydrogenation products per mol of the dihydride complex. The olefin coordinated with ruthenium can be exchanged with other olefins. Olefin-coordinated complexes easily react with molecular hydrogen to afford tetrahydridotris(triphenylphosphine)ruthenium, RuH4(PPh3)3, releasing alkane at room temperature. Under hydrogen atmosphere, catalytic hydrogenation of the olefins smoothly takes place with RuH2(PPh3)4. (Ethylene) tris(triphenylphosphine) ruthenium (0) reacts with methyl iodide to give propylene and a trace of bu adiere along with methane, ethylene, and small amounts of ethane and butenes. The formation of propylene suggests that oxidative addition involving cleavage of the C–H bond of ethylene to ruthenium giving a hydridovinyl complex may be taking place. Reactions of Ru(C2H4)(PPh3)3 with methyl-d3 iodide and ethyl iodide, and of Ru(C3H6)(PPh3)3 with methyl iodide were examined to test the generality of this type of reaction. The reaction of Ru(C2H4)(PPh3)3 with CD3I released CD4 and CD2H2 together with CD3H suggesting the involvement of α-hydrogen abstraction.
Organic Photochemical Reactions. XXIV. Photocycloaddition of Propanal to 1,3-Cyclohexadiene
Authors: Shima Kensuke , Kubota Tadatoshi , Sakurai Hiroshi 
Published: July 2006

Abstract
The photocycloaddition of propanal to 1,3-cyclohexadiene leads to oxetanes, as well as to the dimers of 1,3-cyclohexadiene. A mechanism of oxetane formation is proposed in which singlet excited propanal attacks a ground-state 1,3-cyclohexadiene to give a singlet complex with a charge-transfer character. The complex either decays to the ground-state reactants or reacts to give oxetanes. Quantum yield measurements and kinetic analysis show a rate constant of 4×109 M−1 s−1 for singlet complex formation from propanal and 1,3-cyclohexadiene in benzene. The quenching data of propanal fluorescence support such a mechanism.
The Photochemical Reaction of 2-Alkoxy-1,4-naphthoquinones with Olefins. III. The Re-examination of the Structures of the Photo-addition Compounds and the Reaction Mechanism
Authors: Otsuki Tetsuo 
Published: July 2006

Abstract
In the photochemical reaction of 2-alkoxy-l,4-naphthoquinones with a variety of olefins, two types of photoaddition compounds are found to be produced: the cyclobutane-ring compounds and the oxetanol-ring compounds. Although the present author has assigned the structure of a tetrahydropyran-ring compound to one of the photoaddition compounds primarily on the basis of the analyses of the spectral data, the previously proposed structures should be corrected to an oxetanol-ring compound on the basis of the chemical reactivities. Although some cyclobutane-ring compounds were stable enough to be isolated as final reaction products, the other cyclobutane-ring compounds, though once produced, were too unstable to undergo the subsequent photochemical reaction to give oxetanol-ring compounds on further irradiation. The stability of the cyclobutane-ring compounds was dependent on both the substituents of the olefins and the wavelength of the light. The origin of the stability and the reaction mechanism were investigated.
Concentration Fluctuation and the Light-scattering Spectrum
Authors: Iwasaki Kenji , Tanaka Masami , Fujiyama Tsunetake 
Published: July 2006

Abstract
Light-scattering spectra were observed for binary solutions of carbon disulfide–chloroform at various concentrations. The relation between the Rayleigh-line intensity and the concentration fluctuation was derived. Using the proposed relation and the observed Rayleigh intensity, the concentration dependence of the concentration fluctuation was then determined. The results suggest that chloroform and carbon disulfide molecules have a tendency to get together in the binary solution.
Solvent Effects on the ESR Spectra of Copper(II) Complexes. A Consideration of the Donicity of Water and Methanol
Authors: Ogata Tateaki , Fujisawa Tadashi , Tanaka Nobuyuki , Yokoi Hiroshi 
Published: July 2006

Abstract
Solvent effects on the ESR spectra of bis(2,6-dimethyl-3,5-heptanedionato)copper(II) ([Cu(dibm)2]) and a similar copper(II) complex were investigated in some detail. A clear relationship between the ESR parameters and the donicity of the solvents was confirmed, and this is discussed with the intention of investigating the donicities of water and methanol. The donor number for water in an aqueous solution was estimated to be about 30 from a precise analysis of the ESR spectra of [Cu(dibm)2] in water–methanol mixtures.
Carboxylation of Phenol Derivatives. XXII. Formation of Alkali Alkyl Carbonate by the O-Carboxylation of Alcohol in the Presence of an Alkali Salt of a Weak Acid
Authors: Hirao Ichiro , Kito Taketoshi , Funamoto Takatomo , Murakami Taketoshi , Usami Katsuyuki 
Published: July 2006

Abstract
O-Carboxylation of the alcohol (ROH) occurred to give alkali alkyl carbonate in a good yield when carbon dioxide was introduced into the mixture of an alkali salt of a weak acid, alcohol, and acetone (or THF) at room temperature under atmospheric pressure. Such alkali salts as PhOM, p-R′C6H4OM (R′=CH3, CH3O, or Br), Et2NCSSM, NaCN, and C6H4(CO)2NK (M=K or Na) were effective. The mixture of HOC6H4COOM and ROCOOM was obtained from the reaction using MOC6H4COOM as an alkali salt. However, the mixture was composed of equimolar amounts of p-HOC6H4COOM and ROCOOM when p-MOC6H4COOM was used. In this reaction, two mechanisms have been examined.
The Reaction of Monoketones with Manganese(III) Acetate
Authors: Okano Masayoshi , Aratani Takaaki 
Published: July 2006

Abstract
When acetone, ethyl methyl ketone (EMK), and cyclohexanone were heated with manganese(III) acetate dihydrate in a mixed solvent of glacial acetic acid and acetic anhydride at 100 °C, acetoxy ketones were obtained as common products. Furthermore, ketone dimers (1,4-diketones) were obtained from acetone and cyclohexanone, which also gave 1,2,3,4-tetrahydrodibenzofuran. When mixtures of these ketones and 1-hexene were heated with the oxidant, saturated and unsaturated ketones and γ-acetoxy ketones were obtained as common products, and 2-propylchromene was obtained as a new product from the cyclohexanone-1-hexene mixture. The formation courses of these reaction products are discussed.
Formation of Diorganostannylenes. I. Photolytic Reaction of Dibutyltin with Organic Halides
Authors: Kozima Sinpei , Kobayashi Kazuhiko , Kawanisi Mituyosi 
Published: July 2006

Abstract
The photochemical reactions of dibutyltin, (Bu2Sn)m, with alkyl monohalides, R′X, give Bu2R′SnX-type compounds by the insertion of the intermediately formed dibutylstannylene to the C–X bond of alkyl halides. This provides a facile method for preparing Bu2R′SnX compounds, since the reaction proceeds quickly under mild conditions giving the products in good yields, the only by-product Bu3SnX which can be distilled being obtained only in a low yield. The reactions with dihalomethanes were also successful. The reaction pathway is discussed in connection with the reactivities of the substrates.
The Synthesis of Benzannelated Annulenes. Dibenzo-tetrakisdehydro[18]annulene, and Tribenzo-bisdehydro[14]annulene
Authors: Ojima J\={u}ro , Yokomachi Tadayoshi , Kimura Akihiko 
Published: July 2006

Abstract
In order to establish the effect of the annelation of benzene rings on [4n+2] annulenes, the syntheses of benzannelated dehydroannulenes were attempted. Dibenzo-tetrakisdehydro[ 18]annulenes (IIa and IIb) were prepared according to the reaction sequence developed in the synthesis of tetramethyltetrakisdehydro[18]annulene (I) from o-ethynylbenzaldehyde (VIII); both of them proved to be unstable. Tribenzo-bisdehydro[14]annulene (XVII) was also prepared from VIII by a double Wittig reaction, followed by oxidative coupling. An examination of the NMR spectrum indicated that XVII is atropic.
Absorption Spectra of Four Naphthalenediols with C2V Symmetry. Interpretation by Means of Configuration Analysis
Authors: Fujii Tsuneo , Suzuki Satoshi 
Published: July 2006

Abstract
The electronic absorption spectra of four substituted naphthalenes with two electron-donating groups, 1,4-, 1,8-, 2,3-, and 2,7-naphthalenediols, have been investigated by means of configuration analysis, with particular attention paid to the dependence of the spectra on the positions of substitutions and on the molecular symmetry. The wave functions calculated by the Pariser-Parr-Pople method are analyzed in terms of locally-excited states and intramolecular charge-transfer states. The excited electronic wave functions of naphthalenediols have been expanded not only in terms of the electronic states of naphthalene, but also in terms of those of naphthol. The present configuration analysis shows that the electronic states of all these four naphthalenediols may reasonably interpreted in terms of locally-excited states of the parent compounds and charge-transfer states from the substituents to the parent compounds. The characteristic spectral changes in the Lb, La, and Bb bands caused by substitution are adequately explained in relation to the positions and to the molecular symmetry. The intensification of the Lb band caused by the introduction of the hydroxyl groups is interpreted as due to the mixing between the Lb and Bb bands. The Bb reference state interacts with the Lb and Ag− reference states in 1,4- and 2,3-naphthalenediols, whereas it interacts with the Lb, B1g+, and B1g− reference states in 1,8- and 2,7-naphthalenediols.
X-Ray Photoelectron Spectroscopy of Chloromethanes and Chloroethanes
Authors: Ohta Toshiaki , Kuroda Haruo 
Published: July 2006

Abstract
X-Ray photoelectron spectra of chloromethanes (CH4−nCln, n=2,3,4) and chloroethanes (CH3CH3−nCln, n=1,2,3) in vapor phase were observed employing Mg Kα radiation. The observed Cls binding energies were analyzed by means of Siegbahn’s electrostatic potential model and charge densities calculated by the CNDO/2 method, and the effects of inclusion and exclusion of Cl 3d atomic orbitals in the basis set of the CNDO/2 calculation is critically investigated. The assignment of all valence electron levels of above molecules were performed with the aids of the CNDO/2 calculations incorporated with Gelius’ intensity model and the reported data of ultraviolet photoelectron spectroscopy.
Dehydroannulenes. III. Synthesis and Properties of 1,5,10,14-Tetra-tert-butyl-6,8,15,17-tetrakisdehydro[18]annulene
Authors: Tomita Sachiyo , Nakagawa Masazumi 
Published: July 2006

Abstract
In order to find out substituent groups which provide stability and solubility to tetrakisdehydro[18]annulene system without appreciable electronic interaction with the annulene ring, the synthesis of 1,5,10,14-tetra-tert-butyl-6,8,15,17-tetrakisdehydro[18]annulene (VIII) has been catrried out starting from 3-tert-butyl-2-penten-4-ynal (III). It was found that the tetra-tert-butyl derivative (VIII) is strongly diatropic, and more stable and much more soluble than tetramethyl-, dimethyl-, diphenyl-, and tetraphenyl-analogues. The electronic spectrum of tetra-tert-butyl derivative (VIII) was found to be closely related with that of tetramethyltetrakisdehydro[18]annulene indicating a minor electronic perturbation of tert-butyl groups on the annulene ring.
The Conformations of Copper(II) Complexes with edda-Type Optically Active Polyamino Carboxylic Acids in Aqueous Solutions
Authors: Murakami Tasuku , Hatano Masahiro 
Published: July 2006

Abstract
A copper(II) complex with (S,S)-1,1′-ethylenedipyrrolidine-2,2′-dicarboxylic acid (H2epro) was prepared, and its absorption and CD spectra were measured in an aqueous solution. A weak absorption band at 9500 cm−1 was indicative of the apical coordination of the carboxylate group. Furthermore, from the fact that the effect of unidentate bases, such as pyridine and ammonia, on the absorption and CD spectra of the epro complex was quite different from that of bidentate bases, the epro complex was expected to take a Λ-uns-cis conformation. In addition, the base-addition effect was measured for the complexes of (S,S)-α,α′-dimethyl-N,N′-ethylenediaminediacetic acid(H2eddp), (S,S)-α,α′-diisopropyl-N,N′-ethylenediaininediacetic acid(H2eddv), and (S,S)-α,α′-dibenzy-N,N′-ethylenediaminediacetic acid(H2eddc). The conformations of these complexes are also discussed on the basis of the information obtained for the epro complex.
The Crystal Structure of Bis[1-(2-thiazolylazo)-2-naphtholato]cobalt(III) Perchlorate
Authors: Kurahashi Masayasu 
Published: July 2006

Abstract
The crystal structure of bis[1-(2-thiazolylazo)-2-naphtholato]cobalt(III) perchlorate, [CoIII(C13H8N3OS)2]ClO4 was determined from X-ray reflection data collected by counter methods. The crystals are monoclinic, space group P21/c, with a=10.348(2), b=21.066(5), c=13.072(5) Å, β=112.35(3)°, and Z=4. The structure was determined by the heavy-atom method and refined by the least-squares technique to give an R value of 0.051 for 2696 observed reflections. The cobalt atom is six-coordinate and exhibits octahedral coordination. The 1-(2-thiazolylazo)-2-naphtholato group is coordinated as a terdentate ligand with the cobalt atom through the phenolic oxygen atom, the azo nitrogen atom adjacent to the naphthol ring and the thiazole nitrogen atom giving two five-membered chelate rings. Short intraligand contacts of 2.24(6) and 2.28(6) Å are observed between the azo nitrogen and naphthol hydrogen atoms.
Reactions of 2-Guanidino-1-cyclohexanol with Ketals and Acetals
Authors: Takagi Yasushi , Kawashima Osamu , Tsuchiya Tsutomu , Sano Hiroshi , Umezawa Sumio 
Published: July 2006

Abstract
Reactions of 2-guanidino-1-cyclohexanols (1, 1d, 1l) with 1,1-dimethoxycyclohexane in N,N-dimethylformamide in the presence of p-toluenesulfonic acid gave the N,O-cyclohexylidene derivatives (5, 5d, 5l), respectively. Similar reactions of 1l with 2,2-dimethoxypropane and with dimethyl acetals of p-tolualdehyde and p-bromobenzaldehyde also gave an N,O-isopropylindene, N,O-(p-methylbenzylidene) and N,O-(p-brornobenzylidene) derivative (8l, 9l, 10l), respectively. From IR and PMR spectral studies of 9l p-toluenesulfonate, seven-membered structures as exemplified by 9A were assigned. The N,O-blocked derivatives (5,9) are stable in weakly acidic or alkaline media, but in stronger media, they are cleaved to 1. The usefulness of the protective groups was also examined. 9 was found to resist tosylation or mesylation in pyridine but not acylation. The numerical values of optical rotations of the guanidinocyclohexanols were greatly enhanced by N, O-blocking.