bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acid-Catalyzed Oxidation of Olefins with Selenium Dioxide
Authors: Javaid Khan A , Sonoda Noboru , Tsutsumi Shigeru 
Published: July 2006

Abstract
A drastic deviation from the usually accepted reaction path was observed when oxidation of olefins was carried out in acetic acid with selenium dioxide in the presence of concentrated sulfuric acid. Oxidation of cyclohexene gave a mixture of cis- and trans-1,2-diacetoxycyclohexane. It was shown that in the oxidation of cyclohexene the organoselenium intermediate which produced 3-acetoxy-1-cyclohexene on pyrolysis, is not the intermediate in the present reaction. A study on reaction variables, such as effect of molar ratio of cyclohexene to selenium dioxide, amount of sulfuric acid, and water, reaction time and temperature, was undertaken. The reaction was extended to 1-octene and 1-hexene. A general structure for the organoselenium compound produced in the oxidation of terminal olefins in acetic acid without sulfuric acid, has been proposed. On the basis of our data and some previous concepts a reaction scheme has also been given.
A Study on the Photochemistry of α,β-Unsaturated γ-Lactones. I. The Structures of the Photodimers of 4-Hydroxycrotonic Acid γ-Lactone
Authors: Ohga Kazuya , Matsuo Taku 
Published: July 2006

Abstract
The structures of the photodimers obtained from 4-hydroxycrotonic acid γ-lactone under several conditions were determined. The products of irradiations in the solution were a pair of anti dimers: one is a head-to-head cyclo-adduct, and the other a head-to-tail adduct. The corresponding product in the solid, state, on the other hand, was a head-to-head cyclo-adduct in the syn form.
Reactions of Ferrocenylcarbene. III. The Addition Reactions of Some α-Ferrocenylcarbenes to 1,1-Diphenylethylene
Authors: Sonoda Akio , Moritani Ichiro 
Published: July 2006

Abstract
The addition reactions of α-ferrocenylcarbenes (ferrocenyl, ferrocenylmethyl, and ferrocenylphenyl carbene) to 1,1 -diphenylethylene have been examined by means of the thermal decomposition of the corresponding acylferrocene tosylhydrazone sodium salts. Then, the reactivities of the ferrocenylcarbenes have been compared with those of the corresponding phenyl and p-anisylcarbenes. It has been found that, of the carbenes investigated, the ferrocenylcarbenes show the lowest reactivity in addition reactions to the olefin. It has been established by a study of the NMR spectra that, in the ferrocenylcyclopropanes only, there is a restricted rotation about the bond between ferrocenyl and cyclopropyl groups. On this basis, the reactivity of the ferrocenylcarbenes has been discussed in terms of the steric hindrance of the bulky ferrocenyl group.
The Cycloaddition Reactions of Benzoylsulfene with Anils
Authors: Tsuge Otohiko , Iwanami Sumio 
Published: July 2006

Abstract
The reactions of benzoylmethanesulfonyl chloride with various anils (Ar–CH=N–R) in the presence of triethylamine have been studied. It has been found that the corresponding (4+2) and/or (2+2) cycloadducts of benzoylsulfene and the anil were obtained, depending on the nature of the substituents, R, in the anils. The reaction of the chloride with benzylidene-n-propylamine in the absence of triethylamine gave only the (2+2) cycloadduct, while the (4+2) cycloadduct was exclusively obtained in the presence of triethylamine. The chloride reacted with dibenzylidenethylenediamine in the presence of triethylamine to give the corresponding bis(4+2) cycloadduct.
2H,5H-Triazolo[4,5-d]triazoles. A New Heteroaromatic System
Authors: Yoshida Masayuki , Matsumoto Akira , Simamura Osamu 
Published: July 2006

Abstract
2-Aryl-5-phenyltriazolo[4,5-d]triazoles and related compounds, a new heteroaromatic system, have been prepared from 4,5-diamino-2-phenyl-1,2,3-triazole. The meso-ionic character of the new ring system is discussed on the basis of proton NMR shifts.
Homolytic Aromatic Isopropyloxycarbonyloxylation Induced by Oxygen
Authors: Nakata Toshio , Tokumaru Katsumi , Simamura Osamu 
Published: July 2006

Abstract
Thermal decomposition of diisopropyl peroxydicarbonate in benzene was carried out at several temperatures ranging from 40 to 70°C under an atmosphere of nitrogen, air or oxygen; the presence of oxygen caused the production of isopropyl phenyl carbonate. For this aromatic isopropyloxycarbonyloxylation induced by oxygen, a mechanism is proposed, which involves reversible addition of an isopropyloxycarbonyloxy radical to an aromatic nucleus to give a cyclohexadienyl intermediate, followed by oxidation with oxygen to produce the carbonate ester. The reaction in a mixture of benzene and hexadeuteriobenzene showed isotope effects for the formation of the ester, kH⁄kD=2.1–2.3, thus supporting the reversibility of the addition step of the isopropyloxycarbonyloxy radical to benzene.
Thermal Decarboxylation of Nitrobenzoic Acids. I
Authors: Manikyam D S , Sundaram E V 
Published: July 2006

Abstract
Thermal decarboxylation of o-, m- and p-nitro benzoic acids was studied in glycerol in the temperature range 210–250°C m- and p-Nitrobenzoic acids exhibited first order rate constants and in support of the proposed SE1 mechanism, the isomers were also studied in aniline at 110–140°C. Pseudo-first order rate constants of the ortho isomer in glycerol suggested a change in mechanism from SE1 to SE2. The rate constants were influenced by boric acid or aniline added to glycerol as the result of a change in pH and confirmed thus the proposed SE1 or SE2 mechanisms. Activation energies, enthalpies and entropies of activation were obtained for the three isomers.
Mechanism of Hydrogenolysis. II. A Molecular Orbitals Study of Hydrogenolysis of Toluene
Authors: Tominaga Hiroo , Arai Hiromichi , Kunugi Taiseki , Amano Akira , Uchiyama Masao , Sato Yoshiki 
Published: July 2006

Abstract
In hydrogenolysis of toluene to produce benzene and methane, atomic cracking process H+C6H5CH3→C6H6CH3 (a) or H+C6H5CH3→C6H5+CH4 (b) has been presumed as rate controlling in chain propagation step of the radical chain mechanism. These two alternative processes are compared on the energetics calculated by the extended Hückel M.O. method. The reaction (a), an addition of the attacking hydrogen atom to phenyl carbon atom adjacent to methyl group followed by an elimination of methyl radical in a concerted manner, is found to be the most likely pathway.
Microwave Spectra of Vinylacetylene and Monodeutero Vinylacetylene in Ground and Excited Vibrational States
Authors: Hirose Chiaki 
Published: July 2006

Abstract
The microwave spectra of vinylacetylene, CH2CHCCH, and monodeutero-vinylacetylene, CH2CHCCD, have been observed in the ground state and several vibrational excited states. The vibration-rotation constants α1(a), α1(b), α1(c), α2(a), α1(b), and α1(c), have been obtained as 1 370, −18.32, −7.73, −907, −2.78, and −8.97 MHz for CH2CHCCH, and 2 010, −16.66, −7.05, −1640, −2.18 and −7.84 MHz for CH2CHCCD, respectively, the error limits being ±50 MHz for α(a)’s and ±0.03 MHz for α(b)’s and α(a)’s. Electric dipole moments obtained are 0.223±0.020 and 0.206±0.008 Debye for CH2CHCCH and CH2CHCCD, respectively, which are quite different from the values reported previously.
An ESR Study of an Al2O3-MoO3-CoO Catalyst in a System with H2 and Thio-β-naphthol
Authors: Ueda Hisashi , Todo Naoyuki 
Published: July 2006

Abstract
This work was planned in order to determine the reaction mechanism of the catalytic, direct desulfurization of organic sulfur compounds on the surface of Al2O3-MoO3-CoO particles. The experimental method consists of quantitative ESR measurements, by means of which the paramagnetic species on the surface of Al2O3, Al203-MoO3, and Al2O3-MoO3-CoO in the presence and in the absence of H2 and thio-β-naphthol were studied. As it is expected that, in an ideal and fast-reacting catalytic reaction system, no reaction intermediate can be found because it will be immediately converted to the final product, several artificial reaction systems were investigated in which either one of the reactants, catalyst components, or reaction conditions (e. g., temperature) was deficient. In such deficient systems, the reaction cycle is cut off and some intermediates are expected to accumulate. The paramagnetic species observed were Co3+, Mo5+, thio-β-naphthol+-O*2− or RS+H–O*2−, and some species formed on the surface of Al2O3, in the temperature region of 20°C–200°C. Mo6+ is concluded to be the electron trap to facilitate the formation of RS+H–O*2−, Co3+ is concluded to oxidize the Mo5+ thus formed to Mo6+, and Co2+ is concluded to reduce the R-S+H2–O*2− species. The latter then decomposes to H2S and R·.
The Temperature Dependence of Hole Injection into Anthracene Crystals
Authors: Yamagishi Akihiko , Soma Mitsuyuki 
Published: July 2006

Abstract
The temperature dependence of dark- and photo-currents was studied for the hole injection into anthracene crystals between 0 and 30°C. It was observed that the photocurrent or, as has been previously established, the electron-transfer rate from an excited anthracene crystal to an acceptor had a small temperature dependence, while the dark current or the electron-transfer rate from the crystal in its ground state to an acceptor had a definite value of activation energy. The observed small activation entropy for the dark reaction was interpreted in terms of Marcus’ theory, and the small polarizability of the organic crystal was, accordingly, suggested to increase the probability of the electron transfer.
Dielectric Absorption in Crystalline Pentachloronitrobenzene
Authors: Aihara Ariyuki , Kitazawa Chikazu , Nohara Akira 
Published: July 2006

Abstract
Dielectric measurements have been performed with pentachloronitrobenzene in polycrystalline state using a trans-former bridge, between 30 Hz and 1 MHz and in the temperature range 20–99°C. The substance shows distinct dielectric absorption in the frequency and temperature ranges, presumably due to molecular rotation in the solid state similar to that of pentachlorotoluene and 1,2,4-trimethyl-3,5,6-trichlorobenzene as has been found by Turney. The frequency factor and the energy of the barrier for the rotation are logA=15.2 (A in sec−1) and ΔH=16.1 kcal/mol. A possible mechanism for the rotational transition of the molecule in the crystalline lattice has been discussed. The dipole moment of this substance in benzene solution has been measured, the result being μ=2.33 Debye.
The Preparation of Nitro-Carbonato and -Acetylacetonato Complexes of Cobalt(III) and Their IR and UV Spectra
Authors: Ichikawa Hiroyasu , Shibata Muraji 
Published: July 2006

Abstract
Two new nitro complexes of cobalt(III), K2[Co(NO2)2CO3acac]·H2O and K3[Co(NO2)4CO3]·H2O, have been prepared by the reaction of tricarbonatocobaltate(III) and the desired ligand. The 700–200 cm−1 region IR spectra for these complexes and the other related dinitro complexes have been measured, and the geometrical structures of these dinitro complexes have been determined as of the cis-form on the basis of the IR data. Furthermore, the absorption spectra of these nitro complexes have also been measured, and the stability of these complexes has been related to the spectral data.
The Crystal Structure of (+)589-Dichlorobis(ethylenediamine)cobalt(III) Chloride Monohydrate
Authors: Matsumoto Keiji , Ooi Shun’ichiro , Kuroya Hisao 
Published: July 2006

Abstract
The crystal structure of cis-(+)589-[CoCl2en2]Cl·H2O has been determined by the X-ray-diffraction method. The crystal is monoclinic with the cell constants: a=12.07, b=11.52, c=8.33 Å, and β=96.9°. The space group is P21 and Z=4. There are two crystallographically-independent complexes in the unit cell, but they have the same configuration and almost identical molecular dimensions. The absolute configuration of the complex cation is consistent with that proposed by McCaffery, Mason and Norman and should be denoted as Λ(δδ).
The Ruthenium Complexes Formed by the Reactions of Nitrosylruthenium(III) with Tin(II) in Hydrochloric Acid Solution
Authors: Mukaida Masao 
Published: July 2006

Abstract
The complexes formed by the reactions of nitrosylrutheniurn(III) in hydrochloric acid solutions with tin(II) chloride were investigated. The following reaction products, (Me4N)2[RuCl3(SnCl3)2-NO], [1]; (Me4N)4[RuCl6(SnCl3)2(NO)2]·H2O, [2]; (Me4N)4[RuCl(SnCl3)5], [3] and K3[Ru2-Cl8(H2O)2N], [4] were isolated as crystals and were characterized. On the basis of chemical and thermal analyses, and on the basis of observations of the magnetic properties, the conductivities, and the infrared spectra, it was concluded that complexes [1], [2], and [3] contain terminal or bridging nitrosyl groups and/or a coordinating SnCl3− group, and that complex [4] contains a bridging nitrido group. The presence of the binuclear complex, “K3[Ru2Cl9(NO)2],” which has both the terminal and singly-bridged nitrosyl groups was also suggested. The relations among those complexes were discussed.
A Study of Electronic Spectra of Square Planar Copper(II) and Nickel(II) Complexes by Circular Dichroism
Authors: Nishida Yuzo , Kida Sigeo 
Published: July 2006

Abstract
Using optically active 1,2-propylenediamine we have synthesized several ligands to form square planar Cu(II) and Ni(II) complexes with optical activity. The CD (circular dichroism) and AB (absorption) spectra of these compounds were measured. The broad absorption bands were resolved in the CD spectra into each component due to a d-d transition, to which a specific d-d transition was assigned. It was found that in these compounds the change in the central atom from Cu(II) to Ni(II) dose not alter the main feature of CD and AB spectra. This seems to be the general rule for the planar Cu(II) and Ni(II) complexes.
Stereoselectivity in Mixed Tris-Type Cobalt(III) Complexes with Glycine and l-Aspartic Acid
Authors: Kawasaki Kiyoshi , Yoshii Junko , Shibata Muraji 
Published: July 2006

Abstract
The reaction of the carbonatobis(glycinato)cobaltate(III) with l-aspartate in the presence of active charcoal led to the stereoselective formation of tris(glycinato-l-aspartato) complexes. By means of ion-exchange chromatography and fractional precipitation, four optically-active complexes, mer-Λ- and fac-Δ-[Co(gly)3−n(l-asp)n]n− (n=1,2), have been isolated, and they have been characterized by means of their absorption and circular dichroism spectra. Furthermore, the percent compositions of the geometrical isomers for the complexes (n=1,2,3) in the reaction mixture and also of Λ- (or Δ-) isomers for each geometrical isomer have been estimated using the spectral data. A marked stereoselectivity (&gt;90%) has been found in the fac-Δ-isomers, while an appreciable selectivity (ca. 70%) has been found for the mer isomers. These stereoselectivities have been explained in terms of an enhanced stability through hydrogen bonding between the β-carboxylate group in the coodinated l-aspartate and the amino group in the adjacent ligand.
Absolute Structure of Acacic Acid
Authors: Varshney I P , Shamsuddin K M 
Published: July 2006

Abstract
Acacic acid, a pentacyclic triterpenic acid, is present as a saponin in various members of the family Leguminosae, but the highest yield is obtained from the pods of Acacia concinna DC. On the basis of degradative studies, transformations, IR, UV, NMR, mass spectrography, and ORD, and CD studies its absolute stereochemistry and structure have been fixed as 3β, 16β, 21β-trihydroxy-18β-olean-12-en-28-oic acid and that in the acetate the rings E and D are in boat and quasi-boat forms, respectively, with D/E rings cis fused.
Kinetic Studies of the Triethylenediamine-catalyzed Hydrolysis of 1,3-Diphenylurea in Dioxane
Authors: Furuya Yoshiaki , Itoho Kazuo , Fukutaka Sakiko 
Published: July 2006

Abstract
The rate of the hydrolysis of 1,3-diphenylurea (abbreviated as DPU) in dioxane in the presence of triethylenediamine (TED) was followed by ultraviolet spectrophotometry. The rate of the reaction satisfied the following equation:
v=&{k_2-k_3h[H_2O]}[DPU][H_2O]+{k_4uh[H_2O]-k_3u}[DPU]^2[H_2O]
&+{k_3c-k_4ch[H_2O]}[TED][DPU][H_2O]+{k_5cuh[H_2O]-k_4cu}
&×[TED][DPU]^2[H_2O].
A probable mechanism which involves a nucleophilic attack of the lone pair of the O-atom of water and of the N-atom of TED on the carbonyl C-atom of DPU, passing through an ion pair of quaternary ammonium salt, is discussed.
Hydrolysis of Dipeptides with Metal Oxides
Authors: Suzuki Shinnichiro , Watanabe Ken-ichi 
Published: July 2006

Abstract
The hydrolysis of three dipeptides, Gly-Gly, Gly-l-Leu, and Gly-l-Phe, with metal oxide catalysts was studied. In most cases, the hydrolysis occurred in the pH range 5–6 accompanied by the formation of metal complexes of amino acids and dipeptides. Copper oxide, nickel oxide, cobalt oxide (III), and alumina have more catalytic activity than copper powder, cuprous oxide, commercial nickel oxide (II), and silica gel. Alumina and silica gel gave no metal complex. It is assumed that the hydrolysis proceeds by means of the formation of an active metal complex of dipeptide or by means of activation on the surface of the catalyst. The order of reactivity of the dipeptides was: Gly-Gly&gt;Gly-l-Leu, Gly-l-Phe.
Ester-Urethane Interchange Reaction
Authors: Suzuki Hajime 
Published: July 2006

Abstract
The ester-urethane interchange reaction has been studied by means of gas chromatography and NMR. The interchange reaction between low-molecular-weight ester and urethane was confirmed by the gas chromatography. Alternating copolyester-urethane was prepared by reacting bis-(hydroxyethyl)terephthalate with hexamethylene diisocyanate in anisole. When the polymer is melted at 190°C in the presence of sulfuric acid as a catalyst, the ester-urethane interchange reaction in alternating copolyester-urethane proceeds and causes a more random arrangement of the segments. This was proved by high-resolution nuclear magnetic resonance spectroscopy. An ethylene glycol residue adjacent to terephthalate on both sides, to diisocyanate on both sides, and to terephthalate and diiosyanate could be identified at 4.93, 4.48, and 4.71 ppm respectively in trifluoroacetic acid.
Synthesis of Corticotropin Peptides. XII. The Effect of Amino-terminal Substitution in the Corticotropin 1-18 Peptide
Authors: Inouye Ken , Watanabe Kunio , Namba Keiko , Otsuka Hideo 
Published: July 2006

Abstract
The synthesis and biological properties are described of an octadecapeptide amide, α-aminoisobutyryl-tyrosyl-seryl-methionyl-glutamyl-histidyl-phenylalanyl-arginyl-tryptophyl-glycyl-lysylprolyl-valyl-glycyl-lysyl-lysyl-arginyl-arginine amide, corresponding to the first eighteen amino acid residues of corticotropin (ACTH) except for the amino terminal residue. The amino-terminal decapeptide as intermediate is built up from a tripeptide (positions 1–3) and a heptapeptide (4–10), where a benzyloxycarbonyl and a benzyl ester groups are used for protection of the terminal α-amino group and the γ-carboxyl group of 5-glutamic acid, respectively. These protecting groups are removed in the final step with hydrogen fluoride. The new method is successfully applied to the corresponding 1-β-alanine octadecapeptide amide, which has been synthesized previously by a different procedure. Adrenal-stimulating properties of the 1-α-aminoisobutyric acid peptide are compared with those of the 1-β-alanine peptide to show that the former peptide is more active than the latter when assayed by the adrenal-ascorbic acid depletion and the in vivo steroidogenesis methods. The lipotropic activity of the new peptide is also shown to be more prolonged than that of the 1-β-alanine peptide.
Tri(hetero) substituted Carbonium Ions. VI. An Anomalous Reaction of 2-Methylthio-1,3-dithiolanylium Ion with N,N-Dimethyldithiocarbamate Anion
Authors: Nakai Takeshi , Okawara Makoto 
Published: July 2006

Abstract
The reaction of 2-methylthio-1,3-dithiolanylium ion (III) with N,N-dimethyldithiocarbamate anion (−SN) has been studied with a view toward demonstrating the ambident character of the cation III. It was found that (i) the reaction afforded S-β-(N,N-dimethyldithiocarbamyl)ethyl-S′-methyltrithiocarbonate (IV; normal) together with ethylene bis(N,N-dimethyldithiocarbamate) (V; abnormal); (ii) methylthioxanthate anion (−SS) was formed in the reaction; (iii) the formation of the abnormal product (V) was more favorable and this could not be ascribed to the attack of −SN on the normal product (IV). The ambident reactivity of cation III has been compared with that of closely related cations, tris(methylthio)carbonium ion and 2-methylamino-1,3-dithiolanylium ion (Ia). It was also found that the reaction of Ia with ethylthioxanthate anion (−SS′) afforded the S′-ethyl analog of IV (normal) together with a small amount of abnormal V. The mechanism for the formation of the abnormal product (V) both from III and −SN and from Ia and −SS′ has been suggested.
Steric Effects of Alkyl Substituents upon the Opening of the Lactone Ring of Coumaran-2,3-diones
Authors: Matsuura Teruo , Kawai Masao , Butsugan Yasuo 
Published: July 2006

Abstract
The stability of the lactone rings of alkyl substituted coumaran-2,3-diones against hydrolysis and alcoholysis is greatly affected by the positions of alkyl substituents. From UV spectral studies it was suggested that methyl substitutions at positions adjacent to the lactone ring contribute to stability for steric reasons.
Far Infrared Spectra of Potassium Oxalate Monohydrate and Its Deutero Analog
Authors: Fukushima Kunio 
Published: July 2006

Abstract
The far infrared spectra of potassium oxalate monohydrate and its deutero analog in their crystalline state were measured. Assignment of the infrared absorption bands was made on the basis of frequency shift associated with deuterium substitution of hydrogen atoms in water of crystallization and also on the basis of comparison of neutron scattering spectra of the compounds with the infrared spectra.
νO–H Absorptions and Conformations of Epimeric 1-Tetralols and Chroman-4-ols
Authors: Iwamura Hiizu , Hanaya Kaoru 
Published: July 2006

Abstract
The O–H stretching IR absorptions of epimeric 1-tetralols and chroman-4-ols were examined in dilute carbon tetrachloride solutions. The absorption pattern was found to be related to the conformation of the hydroxyl group; the epimers with the quasi-axial OH group showed a singlet νO–H at 3618 cm−1, while those with the quasi-equatorial hydroxyl had doublet absorption at 3622 and 3600 cm−1. Based on these findings 1-tetralol itself was shown to exist preferentially in the OH axial conformation. The bands at 3618 and 3600 cm−1 were assigned severally to the hydroxyl groups bonding to the π-electrons on the benzene ring. When an additional aryl group is present β to the hydroxyl, another O–H···π bonding to the aryl group becomes possible in addition to that between the OH group and the benzene ring of the tetralin and the chroman skeletons. The conformation of the aryl substituents was deduced by applying the empirical correlation relating the geometry of the molecule to the bonded νO–H frequency in a wide variety of aromatic alcohols which incorporate β-arylethanol moiety.
Separation Factors for Several Lanthanon Pairs Obtained at 60°C in the Ion-Exchange System Involving EDTA
Authors: Hagiwara Zenzi , Noguchi Masaru 
Published: July 2006

Abstract
With a view to the accurate determination of the separation factors of adjacent rare-earth pairs between the aqueous and resin phases, measurements have been carried out at 60°C in the exchange system involving EDTA and Dowex 50W, X-8, 50–100 mesh. Under the same experimental conditions as were used for the isolation of the rare earths by ion exchange, the separation factors at 60°C were found to be 3.43 for Nd-Sm, 1.37 for Eu-Gd, 1.84 for Tb-Y, 1.54 for Y-Dy, 2.83 for Tb-Dy, 1.84 for Dy-Ho, and 2.02 for the Ho-Er and Er-Tm pairs. Further, the observed values were discussed from the viewpoints of both thermodynamics and the real elution of the rare earths by an ion-exchange column.