bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of the Interaction of Excited Chloranil with Acrylonitrile, Methyl Methacrylate, and Styrene by Means of Laser Photolysis
Authors: Kobashi Harumichi , Gyoda Hitoshi , Morita Toshifumi 
Published: July 2006

Abstract
The behavior of electronically excited chloranil interacting with the titled vinyl compounds and solvents has been studied by means of the nanosecond laser photolysis technique. Semiquinone radicals and/or chloranil anions have been detected as transients except in the system containing styrene. Careful observation and analysis of the kinetic behavior of the transient absorptions reveal that these transients are brought about by the interaction of excited triplet state of chloranil with vinyl monomers and/or solvents. The logarithms of the quenching rate constants and rate constants of the formation of transients are linearly related to the ionization potentials of the vinyl monomers and solvents used. The mechanisms of the triplet quenching and transient formation can reasonably be interpreted by taking the relaxed triplet-state complex with a charge-transfer character into account as the precursor leading to the production of semiquinone radicals, chloranil anions, and other intermediate compounds.
The Structure of Ikarugamycin, an Acyltetramic Acid Antibiotic Possessing a Unique as-Hydrindacene Skeleton
Authors: Ito Shosuke , Hirata Yoshimasa 
Published: July 2006

Abstract
The structure and configuration of an antibiotic, ikarugamycin, have been established to be 1e on the basis of chemical reactions, especially of oxidative degradation. It is suggested that the as-hydrindacene skeleton arises biogenetically via an intramolecular Diels-Alder reaction.
New Method for the Preparation of Carboxylic Esters
Authors: Saigo Kazuhiko , Usui Masahiro , Kikuchi Kazunori , Shimada Eiichiro , Mukaiyama Teruaki 
Published: July 2006

Abstract
Various carboxylic esters including functionalized ones are prepared in good yields from equimolar amounts of free carboxylic acids and alcohols under mild conditions by the use of 2-chloro- or 2-bromopyridinium salt, a new and efficient coupling reagent.
The Effect of Water Vapor on Contamination of Metallic Oxide Surfaces
Authors: Tamai Yasukatsu , Matsunaga Toshiaki , Suzuki Kazutomi 
Published: July 2006

Abstract
The contamination rates of the clean surfaces of metallic oxides by liquid-paraffin vapor are largely reduced by the coexisting water vapor. They are related to the hydrophilicity of oxides evaluated as the water-solid interaction free energy by the two-liquid-contact-angle method.
Emission Spectra of CH(A2Δ) Produced from CH3CN in the Argon Flowing-Afterglow Reaction
Authors: Suzuki Kaoru , Kuchitsu Kozo 
Published: July 2006

Abstract
Emission spectra from CH(A2Δ) formed in the reaction of positive ionic species of argon with CH3CN were studied by the flowing-afterglow method. The rotational distributions for the v′=0, 1, and 2 of CH(A2Δ) are characterized by effective rotational temperatures of ca. 5000, 2000, and 1500 K, respectively, whereas the distributions in lower levels (N′\lesssim11), especially for v′=0, are characterized by that of ca. 700 K. The average vibrational and rotational energies distributed in the CH radicals produced initially are estimated to be 0.32±0.04 and 0.34±0.06 eV, respectively.
On the Phase Transition of Ammonium Hexafluoroferrate(III)
Authors: Moriya Keiichi , Matsuo Takasuke , Suga Hiroshi , Seki Syûzô 
Published: July 2006

Abstract
The heat capacities of (NH4)3[FeF6] crystal have been measured from 15 to 350 K with an adiabatic calorimeter. A heat capacity anomaly was observed at 267.02±0.05 K. The enthalpy and entropy changes of the transition are 6490±500 J mol−1 and 24.8±1.9 J K−1 mol−1, respectively. This value of entropy was discussed in terms of a model involving orientational disorder of the ammonium as well as hexafluoroferrate(III) ions. Based on the assumption of the average fcc symmetry of the crystal and internal rigidity of the ions, the proposed model predicts the transition entropy equal to R In 16=23.05 J K−1 mol−1 which is in close agreement with the experimental value. Temperature dependent splitting of the Raman band due to the internal vibration of the anion was found to be consistent with the model. The excess heat capacity follows the prediction of the Landau theory of phase transitions of the second kind. Properties of the present and the similar crystals including ammonium and alkali salts of hexafluoro-complex ions were discussed in terms of the ionic orientational disorder.
Deoxygenation of Nitrobenzene by Tributylphosphine in the Presence of Alcohols. Synthesis of 2-Alkoxy-3H-azepines
Authors: Masaki Mitsuo , Fukui Kiyoshi , Kita Junichiro 
Published: July 2006

Abstract
Deoxygenative reduction of nitrobenzene by tributylphosphine in the presence of primary or secondary alcohols gave 2-alkoxy-3H-azepines in good yields. The use of acidic hydroxylic compounds, such as phenol or acetylacetone, in place of the alcohols did not lead to ring enlargement. Triphenylphosphine could be used as a reducing agent, but the yields of the azepines were relatively low. 2-Alkoxy-3H-azepines were converted into 2-amino-3H-azepine in good yields by the reaction with ammonium carbonate. 2,3-Dihydro-1H-azepin-2-one was prepared by the hydrolysis of 2-butoxy-3H-azepine or 2-amino-3H-azepine.
Photochemical Reaction of Diphenylcyclobutenedione Derivatives. Formation and Reaction of Conjugated Bisketene and Its N-Analog
Authors: Obata Naruyoshi , Takizawa Takeo 
Published: July 2006

Abstract
The photolysis of diphenylcyclobutenedione derivatives (Va, b) under N2 and that in the presence of substrate, O2 or isocyanide, have been studied. The former resulted in the recovery of a large amount of V and the fragmentation; the latter gave the insertion products into V, diphenylmaleic anhydrides and iminocyclopentenones in good yield. The intermediates, bisketene and ketene-ketenimine as primary photo products were confirmed by the photolysis of Va in methanol to give succinates and by low-temperature IR-technique. Structural aspects of bisketene intermediate were discussed.
Determination of Micropore Volumes of Active Carbon Using Dubinin-Radushkevich Plots
Authors: Tsunoda Ryoichi 
Published: July 2006

Abstract
The adsorption of methanol on active carbons at 30 °C was carried out and a new method for determining the micropore volume in the Dubinin-Radushkevich plot is presented. From this method, it was found that the adsorption volume (V) corresponding to the adsorption potential (A=RTlnP0⁄P), at which the plot of dV⁄d(−A) vs. A has its minimum value, is the value of the micropore volume in cases where extrapolation of the Dubinin-Radushkevich plot cannot be applied because of non-linearity of the Dubinin-Radushkevich plot.
The Reaction of Copper(I) Methyltrialkylborates with Allylic Halides or 2-Propynylic Halides
Authors: Miyaura Norio , Itoh Mitsuomi , Suzuki Akira 
Published: July 2006

Abstract
The reactions between copper(I) methyltrialkylborates (readily obtainable from organoboranes) and allylic halides or 2-propynylic halides were found to give corresponding alkylation products. These reactions provide novel synthetic routes to 1-alkenes or 1,2-alkadienes from organoboranes.
Synthesis of 4′-Vinylbenzo-15-crown-5 from Benzo-15-crown-5
Authors: Kikukawa Kiyoshi , Nagira Kazuhiko , Matsuda Tsutomu 
Published: July 2006

Abstract
4′-Vinylbenzo-15-crown-5 was conveniently synthesized in 30% yield by the reaction of diazotized 4′-aminobenzo-15-crown-5 with ethylene (6–10 kg/cm2) in the presence of zerovalent palladium at room temperature.
Electronic Structures and Spectra of the Keto and Enol Forms of Acetylacetone
Authors: Nakanishi Hiroshi , Morita Hiroshi , Nagakura Saburo 
Published: July 2006

Abstract
Near and vacuum UV absorption spectra of acetylacetone were measured in the vapor phase and in several organic solvents at various temperatures. From the temperature dependence of the spectra, the equilibrium constant and enthalpy change between the keto and enol forms of acetylacetone were determined to be 25 at 20 °C and −4.3 kcal/mol, respectively, in the vapor phase. Rydberg excitation bands were observed at 47170 and 53300 cm−1 for the enol form, and ≈52000 cm−1 for the keto form. The estimated values of the quantum defect indicate that the Rydberg orbitals are 3s and 3p. A modified CNDO-CI method was applied to the valence-shell transitions. A weak band observed at ≈34000 cm−1 for the keto form was assigned to the first n-π* transition, and relatively strong bands observed at 38020 and 56800 cm−1 for the enol form, to the first and second π-π* transitions, respectively. Special attention was paid to the charge-transfer (CT) character pertinent to the intramolecular hydrogen bond in the excited states of the enol form. Configuration analysis of the wave functions revealed us that the first π-π* band observed at 38020 cm−1 has the CT character.
Transition-metal Complexes of Pyrrole Pigments. XIV. An Electron Spin Resonance Study of Bis(3,3′,5,5′-tetramethyldipyrromethenato)manganese(II)
Authors: Matsuda Yoshihisa , Murakami Yukito 
Published: July 2006

Abstract
Bis(3,3′,5,5′-tetramethyldipyrromethenato)manganese(II) in single crystalline and powdered sample states was investigated by means of K-band ESR spectroscopy. The spectral shape for the single crystal depends highly on the angle between the external magnetic field and the crystal axes. Anisotropic parameters D and E evaluated by the simulation method are 0.12±0.01 and 0.032±0.004 cm−1, respectively. These values are considerably larger than those expected for the distorted tetrahedral manganese(II) complexes formed with four equivalent donor atoms. An origin of these large anisotropic parameters has been discussed.
Preparation and Resolution of a Complete Series of [Co(en)x(tn)y(tmd)z]3+ Complexes
Authors: Kojima Masaaki , Yamada Hiroyuki , Ogino Hiroshi , Fujita Junnosuke 
Published: July 2006

Abstract
A complete series often complexes, [Co(en)x(tn)y(tmd)z]3+ (en=ethylenediamine; tn=trimethylenediamine; tmd=tetramethylenediamine) was obtained by preparing four new complexes, [Co(en)(tmd)2]3+, [Co(tn)2(tmd)]3+, [Co(tn) (tmd)2]3+, and [Go(en) (tn) (tmd)]3+. The new complexes were resolved into optical isomers by SP-Sephadex column chromatography. The absorption and circular dichroism spectra of all the complexes were recorded and discussed.
5-Fluorouracil Derivatives. I. The Synthesis of 1-Carbamoyl-5-fluorouracils
Authors: Ozaki Shoichiro , Ike Yoshimasa , Mizuno Haruo , Ishikawa Katsutoshi , Mori Haruki 
Published: July 2006

Abstract
The toxicity and tumor affinity of 5-fluorouracil (1) have been modified by the introduction of a carbamoyl group. Carbamoylation by three general methods were studied extensively: (i) The reaction of 1 with isocyanate, (ii) the reaction of 1-chloroformyl-5-fluorouracil with amine, and (iii) the reaction of 1 with carbamoyl chloride. These three methods usually give 1 -carbamoyl-5-fluorouracils (2). 3-Carbamoyl-5-fluorouracils were not obtained by any method. The 2 substances take a hydrogen-bonded structure in chloroform, a non hydrogen-bonded structure in DMSO at 80 °C, and mixed structures in DMSO at 25 °C. Thirty-six homologues shown by 2 were prepared all of these compounds showed antitumor activity. Of them, 1-hexylcarbamoyl-5-fluorouracil (HCFU) appeared to be the most promising antitumor agent when administered orally in that HCFU retains well balanced lipo- and hydro-philicity, is stable in acid in the stomach, and moreover, decomposed moderately in a tumor. Isocyanate was obtained from the reaction of amine with trichloromethyl chloroformate (TCF) by simply heating these two reagents in toluene; this offers a convenient new method for synthesizing isocyanate from amine. Several new isocyanate were obtained from amino acids.
Indirect Chemiluminescence from the Air Oxidation of Ketones and Carboxylic Acids in Alkaline Aprotic Solvents Containing 9,10-Diphenylanthracene and 9,10-Dibromoanthracene
Authors: Kamiya Isao , Sugimoto Takashi 
Published: July 2006

Abstract
A number of ketones and carboxylic acids have been examined for direct and indirect chemiluminescence with 9,10-diphenylanthracene and 9,10-dibromoanthracene by air oxidation. From the finding that the efficiency of the chemiluminescence was dramatically influenced by the class of the C–H bond adjacent to the carbonyl group, it was concluded that the molecules with a –COCH– group surely give an excited product during air oxidation in alkaline aprotic solvents. The reaction scheme was consistent with the evidence that most simple carboxylic acids exhibited no chemiluminescence, probably because the C–H bond adjacent to the carboxyl group is no more acidic, but keto acids exhibited emission. In several compounds, however, the chemiluminescent reaction was retarded by other functional groups.
The Formation and Structure of Bi1.34CrNbO6
Authors: Torii Yasuyoshi , Hasegawa Kanemitsu 
Published: July 2006

Abstract
A new ternary oxide Bi1.34CrNbO6 was prepared and characterized. The unit cell is face-centered cubic with a=10.455 Å. The structure is assumed to be of the pyrochlore type based on the space group Fd3m and was refined by trial and error to a reliability factor R of 0.0564. This pyrochlore phase was confirmed to have vacancies at the A sites and also at the special oxygen sites, and may be considered to be a rare case in this respect. The Cr3+ and Nb5+ ions are bonded octahedrally to six oxygen atoms at 2.03 Å, while the Bi3+ ions are bonded to six oxygen atoms at 2.56 Å. The structure consists of bismuth tetrahedra, the centers of which are vacant. The highly polarizable Bi3+ ion plays an important role in the formation of the defect pyrochlore structure. Related pyrochlores were also prepared.
Stereochemistry of Cobalt(III) Complexes with Thioethers. II. Geometrical Isomers, Absorption, and Circular Dichroism Spectra of Bis(terdentate-N,S,O) Complexes
Authors: Yamanari Kazuaki , Hidaka Jinsai , Shimura Yoichi 
Published: July 2006

Abstract
Two cobalt(III) complexes containing terdentate thioethers, bis[(2-aminoethylthio)acetato]cobalt(III)(1+), and bis[3-(2-aminoethylthio)propionato]cobalt(III)(1+) were prepared and separated into five and six geometrical isomers, respectively, by ion-exchange column chromatography. The isomers were identified on the basis of their electronic absorption and NMR spectra. The circular dichroism spectra of optically resolved isomers were measured and discussed in relation to the absolute configurations.
Syntheses of d-Arabinofuranosyl and 2′-Deoxy-d-ribofuranosyl 1,2,3-Triazolecarboxamides
Authors: Makabe Osamu , Suzuki Hiroshi , Umezawa Sumio 
Published: July 2006

Abstract
Several d-arabino- and 2′-deoxy-d-ribonucleosides of 1,2,3-triazolecarboxamides were synthesized by two methods, one involving acid-catalyzed fusion reactions of 1-O-acetyl derivatives (3, 5) of the corresponding sugars and 1,2,3-triazole-4-carboxylate (1), and the other by glycosylation of the trimethylsilyl derivative (2) of 1 with glycosyl halides (4, 6). Evidence for the N-glycosylation sites and anomeric configurations of the resulting nucleosides is presented.
Metal-catalyzed Organic Photoreactions. Photoreactions of Compounds Containing a Carbon-oxygen or Carbon-nitrogen Multiple Bond with Alcohols in the Presence of Titanium(IV) Chloride or Uranyl Chloride
Authors: Sato Tadashi , Yoshiie Shigeo , Imamura Takashi , Hasegawa Kazumi , Miyahara Masayuki , Yamamura Shigeo , Ito Osamu 
Published: July 2006

Abstract
α,β-Unsaturated carbonyl compounds and esters, cyclopropyl ketones, β-diketones, Schiff’s bases, and nitriles were irradiated in several alcohols in the presence of titanium(IV) chloride or uranyl chloride. In the titanium(IV) chloride-catalyzed reactions, the α-carbon atom of the primary alcohols underwent a bond formation, generally with the C=X (or C≡N) carbon atom of the substrates, while the bond formation occurred on a C=C carbon atom of the substrates in the uranyl chloride-catalyzed reactions. The reactions were examined under several conditions, and a possible scheme for the reactions was suggested.
Studies on the Nitration of m-Cresol. A New Selective Method for the Preparation of 3-Methyl-6-nitrophenol
Authors: Sasaki Mitsuru , Nodera Katsuji , Mukai Kunio , Yoshioka Hirosuke 
Published: July 2006

Abstract
A new selective method for the nitration of m-cresol has been established. 3-Methyl-6-nitrophenol was most efficiently prepared by nitration of 3-methyl-4-sulfophenyl carbonate or phosphate and subsequent hydrolysis and desulfonation. Steric effects on the attacks of sulfonium or nitronium ion to the phosphate are discussed.
Efficient Methods for Oxidation of Alcohols
Authors: Narasaka Koichi , Morikawa Anri , Saigo Kazuhiko , Mukaiyama Teruaki 
Published: July 2006

Abstract
Treatment of alkoxymagnesium bromides, prepared in situ from alcohols and Grignard reagent, with N-chlorosuccinimide, m-chloroperbenzoic acid, or (diacetoxyiodo)benzene in the presence of t-butoxymagnesium bromide afforded the corresponding carbonyl compounds in good yields. A wide variety of alcohols, after being converted into their bromomagnesium salts by treatment with propylmagnesium bromide, were also selectively oxidized with 1,1′-(azodicarbonyl)dipiperidine to afford the corresponding ketones or aldehydes in excellent yields.
The Thallium(I) Salt-catalyzed Formation of Isothiocyanates from Isocyanides and Disulfides
Authors: Tanaka Sakuya , Uemura Sakae , Okano Masaya 
Published: July 2006

Abstract
The reactions of various isocyanides with diacyl disulfides or tetraethylthiuram disulfide occur smoothly in the presence of thallium(I) acetate and thiocarboxylates in various organic solvents to give the corresponding isothiocyanates in good yields. Lead(II) acetate has an activity almost identical with that of thallium(I), while cadmium(II) and silver(I) acetates and copper(I) oxide show a slightly lower activity than the above thallium and lead salts. An ionic scheme involving a complex formation between the metal salt and one S atom of the disulfide, followed by a nucleophilic attack of isocyanide on the adjacent S atom, is proposed for this reaction. It is revealed that the reaction of isocyanide with one equivalent of thallium(III) thiobenzoate in refluxing chloroform similarly affords a good yield of the isothiocyanate through the above mechanism after the decomposition of the thallium(III) salt to thallium(I) thiobenzoate and dibenzoyl disulfide, rather than through a pathway involving thiothallation (α-addition).
The Studies of the Activated Compound. III. A Synthesis of Muscalure: (Z)-9-Tricosene
Authors: Abe Kyo , Yamasaki Tomio , Nakamura Nobuo , Sakan Takeo 
Published: July 2006

Abstract
A synthesis of muscalure, (Z)-9-tricosene, was carried out as an application of metal-induced acylation.
Synthesis of a Peptide Lactone, N-(3-Hydroxypicolinyl)-threonyl-d-leucyl-prolylsarcosyl-leucyl-alanyl-alanine Threonine Lactone
Authors: Kinoshita Hideki , Kotake Hiroshi 
Published: July 2006

Abstract
The synthesis of a peptide lactone, N-(3-hydroxypicolinyl)-threonyl-d-leucyl-prolylsarcosyl-leucyl-alanyl-alanine Threonine Lactone (21) is described. The t-butoxycarbonyl group of t-butyl O-(t-butoxycarbonyl-alanyl)-N-benzyloxycarbonyl-threonyl-d-leucyl-prolylsarcosinate (12) was deblocked selectively with formic acid in good yield. The coupling of 12 with the azide derived from t-butoxycarbonyl-leucyl-alanine hydrazide (15) with isopentyl nitrite gave a heptapeptide ester 17. Deblocking, cyclization, and hydrogenation gave a heptapeptide lactone 20 which was coupled with 3-hydroxypicolinic acid yielding 21.
Carbon-13 NMR Spectra of Methyl-1,3-dioxolanes
Authors: Senda Yasuhisa , Ishiyama Jun-ichi , Imaizumi Shin 
Published: July 2006

Abstract
The 13C NMR spectra of thirteen methyl substituted 1,3-dioxolanes were measured. The carbon chemical shifts of the methyl groups imply that the 1,3-transannular nonbonded interaction of the methyl groups is negligible, except in the cases of 2,2,4-trimethyl- and 2,2,4,5-tetramethyl-1,3-dioxolanes.
Cyclopropanes from Allylic Halides. I. Synthesis of Dimethyl 3-(2-Methyl-1-propenyl)-2,2-dimethylcyclopropane-1,1-dicarboxylate and Pyrocin as Precursors of Chrysanthemic Acid
Authors: Torii Sigeru , Tanaka Hideo , Nagai Yosio 
Published: July 2006

Abstract
Dimethyl 3-(2-methyl-1-propenyl)-2,2-dimethyl-cyclopropane-1,1-dicarboxylate and pyrocin as precursors of chrysanthemic acid were synthesized by the reaction of (2-halo-2-methylpropylidene)malonate with 2-methyl-1-propenylmagnesium bromide.
Reactions of Benzyne with Substituted Benzenes
Authors: Tabushi Iwao , Yamada Hidenori , Yoshida Zenichi , Oda Ryohei 
Published: July 2006

Abstract
The reactions of benzyne with substituted benzenes (anisole, chlorobenzene, methyl benzoate, benzylidyne trifluoride and toluene) giving the Diels-Alder adducts were investigated, where two positionally isomeric adducts were possible, i.e., a geminal-para adduct (1,4-adduct with respect to the substituent) and an ortho-meta adduct (2,5-adduct). From the competition reactions, relative reactivities of benzyne to substituted benzenes were estimated for the 1,4-addition and 2,5-addition. Markedly different substituent effects were observed. For the 1,4-addition, large negative ρ value (−1.79) was observed, but for the 2,5-addition, substituent effect was small. From benzyne and toluene, o-benzylbiphenyl (13) and 2-benzyl-3-phenylbenzo[5,6]bicyclo[2.2.2]octatriene (14) were obtained as the successive “ene” products together with the normal Diels-Alder adducts.
Violet Emission Spectra of CN(B2Σ) Produced in the Photodissociation of HCN and DCN
Authors: Tatematsu Setsuko , Kuchitsu Kozo 
Published: July 2006

Abstract
Emission spectra of the CN violet band system (B2Σ-X2Σ, Δυ=0) produced in the photodissociation of HCN and DCN by Lyman-α radiation (121.6 nm) were observed with resolution of about 0.2 nm and with sample pressures of 0.01–1.5 Torr. The spectral features of the two were similar, but the main peaks (υ′=0–4) from DCN appeared more sharply than the corresponding peaks from HCN. The relative vibrational populations and the effective rotational temperatures were estimated by a band-envelope analysis. No indication of vibrational population inversion was observed. The CN(B2Σ) radical produced from DCN is likely to have slightly higher vibrational (0.31±0.08 eV) measured from the zero-point energy) and rotational energies (0.15±0.02 eV) than that from HCN (0.23±0.08 and 0.11±0.02 eV, respectively).
Processes in the Reaction of Y2O3 with WO3
Authors: Kuribayashi Kiyoshi , Sata Toshiyuki 
Published: July 2006

Abstract
The processes of the solid state reaction of Y2O3 with WO3 were studied for samples mixed in the molar ratios of Y2O3 : WO3=1 : 3, 1 : 1, 7 : 4, 5 : 2, and 3 : 1. It was found that all the reactions except Y2O3 : WO3= 5 : 2 from the powders of both Y2O3 and WO3 in air proceeded according to the following order step reactions: Y2O3·3WO3→Y2O3·WO3→7Y2O3·4WO3→5Y2O3·2WO3 and 5Y2O3·2WO3→3Y2O3·WO3, with temperatures rising from 600 to 1300 °C and with an unknown compound, X, always first formed below 700 °C. In a reaction couple in contact with both Y2O3 and WO3 pellets, WO3 components preferentially diffused to the Y2O3 side to form Y2O3·3WO3 (orthorhombic form) on the boundary between them at 1000 °C.