bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bromochlorination of Alkenes with Dichlorobromate (1−) Ion. IV. Regiochemistry of Bromochlorinations of Alkenes with Molecular Bromine Chloride and Dichlorobromate (1−) Ion
Authors: Negoro Takeshi , Ikeda Yoshitsugu 
Published: July 2006

Abstract
The regioselectivity of the addition of molecular bromine chloride to alkenes is dependent on both the steric and electronic effects of the alkyl substituent. In contrast, the regioselectivity of the addition of dichlorobromate (1−) ion to alkenes is controlled mainly by the steric effect of the substituent.
Crystal and Molecular Structures of the Adduct of Fluoreno[9,1-bc]pyrylium-3-olate with Methyl Cinnamate and the Dimer of Fluoreno[9,1-bc]pyrylium-3-olate
Authors: Fukuyama Keiichi , Fujita Hideo , Tokushima Shigeru , Tsukihara Tomitake , Katsube Yukiteru , Motoyama Tadayuki 
Published: July 2006

Abstract
The molecular structures of the adduct of fluoreno[9,1-bc]pyrylium-3-olate with methyl cinnamate (1), C25H18O4, and the dimerized product of fluoreno[9,1-bc]pyrylium-3-olate (2), C30H16O4, have been determined by the X-ray diffraction method. In the adduct (1), the phenyl ring is situated above the fluorene ring with a dihedral angle of 64°. The product 2 has a dimeric structure with a head-to-head type anti-configuration, and a local two-fold symmetry. Both crystals belong to a triclinic system with a space group P\bar1. The cell constants for 1 are a=13.287(4), b=8.794(3), c=8.797(3) Å, α=109.78(3), β=82.17(3), γ=88.58(3)°, and those for 2 are a=10.401(2), b=12.425(3), c=8.564(2) Å, α=103.77(4), β=108.76(4), γ=95.06(4)°. The structure of 1 was refined to R=0.067 for 2141 reflections, and that of 2 to R=0.058 for 2301 reflections.
Carbon Monoxide Adsorbent Composed of Copper(I) Chloride and Polystyrene Resin Having Amino Groups
Authors: Hirai Hidefumi , Wada Keiichiro , Kurima Kazunori , Komiyama Makoto 
Published: July 2006

Abstract
A novel adsorbent of carbon monoxide (CO) is prepared by stirring copper(I) chloride and a macroreticular type polystyrene resin having amino groups in acetonitrile, followed by removal of the liquid phase at 5 mmHg, 80 °C. The adsorbent rapidly adsorbs carbon monoxide from 9 : 1 carbon monoxide–nitrogen mixture at 20 °C under 1 atm. The adsorbed carbon monoxide is readily desorbed by heating the adsorbent to 80 °C under 1 atm or by reducing the partial pressure of carbon monoxide to 5 mmHg at 20 °C. The CO adsorbing capacity (15.9 mmol) of the adsorbent composed of 10.0 g of the resin and 70 mmol of copper(I) chloride is 5.7 times as large as the carbon dioxide adsorbing capacity (2.8 mmol). The efficient adsorption of carbon monoxide by the present adsorbents is attributed to coordination of carbon monoxide to the copper(I) ions which coordinate the amino residues in the resin. The carbon dioxide adsorbing capacity (2.8 mmol) of the adsorbent is much smaller than that (8.3 mmol) of the resin without copper(I) chloride. The present adsorbent exhibits no measurable adsorptions of methane, nitrogen, and hydrogen at 20 °C under 1 atm, and thus is applicable to selective separation of carbon monoxide from gas mixtures containing these gases and carbon dioxide.
Synthesis of 2-Pyrrolidinylideneacetates by Means of a Reaction of Magnesium Ester Enolate with γ-Cyanoalkyl Tosylates
Authors: Kobayashi Kazuhiro , Suginome Hiroshi 
Published: July 2006

Abstract
We describe a new and efficient synthesis of t-butyl 2-pyrrolidinylideneacetate and its 3-substituted derivatives from a reaction of the magnesium enolate of t-butyl acetate with γ-cyanoalkyl tosylates.
Cyclic Peptides. XXIII. Synthesis of Retro-Enantio-AM-Toxin I
Authors: Mihara Hisakazu , Aoyagi Haruhiko , Ueno Tamio , Kato Tetsuo , Izumiya Nobuo 
Published: July 2006

Abstract
To characterize a receptive substance in an apple leaf of phytotoxic AM-toxin I, retro-enantiomer of the toxin was synthesized by the solution method. This analog showed no toxic activity, indicating that the specific backbone conformation of the toxin is essential for the activity.
Studies on the Valence State of Iron Atoms in the Mixed-Valence Binuclear Ferrocenes by X-Ray Absorption Near Edge Structure (XANES) and by X-Ray Photoelectron Spectroscopy (XPS)
Authors: Iwai Kumiko , Iwai Makoto , Suto Kyoko , Nakashima Satoru , Motoyama Izumi , Sano Hirotoshi , Ikemoto Isao , Kosugi Nobuhiro , Kuroda Haruo 
Published: July 2006

Abstract
In order to study the valence state in the mixed-valence binuclear ferrocenes, X-ray absorption spectra near the Fe K-edge were measured using synchrotron radiation. Well-resolved lines in the spectra obtained for ferrocene derivatives were assigned to the 1s→3d, 1s→Cp(π*), and 1s→4p transitions, respectively, based on the molecular orbitals. There is an apparent difference in the 1s→3d transitions between trapped-valence compounds and averaged-valence compounds in the I3− salts of the monocation of binuclear ferrocenes. The valence states of the mixed-valence binuclear ferrocenes were also studied by X-ray photoelectron spectroscopy.
Effect of Pressure on the Adsorption and Micelle Formation of Aqueous Dodecyltrimethylammonium Chloride–Cyclohexane System
Authors: Yamanaka Michio , Aratono Makoto , Motomura Kinsi 
Published: July 2006

Abstract
The interfacial tension of aqueous dodecyltrimethylammonium chloride (DTAC) solution–cyclohexane system was measured as a function of pressure at concentrations around the critical micelle concentration (cmc). The derivative of interfacial tension with respect to pressure was observed to change abruptly at the cmc. The volume changes associated with the adsorption of DTAC from its monomeric and micellar states and the volume of micelle formation were calculated and compared with the corresponding ones of the aqueous DTAC solution–hexane system. It was found that the molar interfacial excess volume of the adsorbed film is slightly larger than the molar volume of micelle in the case of the cyclohexane system, while in the case of the hexane system the former is approximately equal to the latter. Further, it was concluded that the micellar particles solubilize molecules of the oil coexisting in equilibrium with the aqueous solution. It was also proved in the case of the present system that the micelle formation can be treated thermodynamically as the appearance of a macroscopic bulk phase in the solution.
Photochemical Magnetic-Field Effects of Isoquinoline N-Oxide in Various Alcohols
Authors: Hata Norisuke 
Published: July 2006

Abstract
A pronounced solvent dependence of the magnetic-field effect due to the HFI-J mechanism was found for the first time in the case of a photochemical isomerization of isoquinoline N-oxide into lactam (1-isoquinolone). The chemical yield of the lactam showed a minimum at a higher magnetic field as one changes the reaction medium from t-butyl alcohol to 2-propanol (or ethanol) and then to methanol, which was the same order as the pKa value (t-butyl alcohol&gt;2-propanole≈ethanol&gt;methanol). Such a solvent dependence provides corroborating evidence that the photoisomerization proceeds via the S1-born singlet radical-ion-pair intermediate, which is linked by a hydrogen bond between the N→O group in the cation radical of N-oxide and the OH group in the anion radical of alcohol. Another interesting finding was that, in the case of the photochemical isomerization in t-butyl alcohol, the chemical yield of the lactam showed distinct maxima at approximately 0.9T and 1.35T in addition to a minimum at about 0.72T. The anomalous magnetic-field effect in a high field region (&gt;0.8T) could reasonably be explained in terms of an HFI-J mechanism by assuming the T1-born triplet hydrogen-bonded radical-ion pair to have an electron-exchange interaction larger than that in the S1-born singlet hydrogen-bonded radical-ion pair.
Nuclear Magnetic Resonance Studies of Copper(I) Complexes of Imidazoles. I. Their Preparation, Characterization, Equilibria, and Reaction with Carbon Monoxide
Authors: Kitagawa Susumu , Munakata Megumu 
Published: July 2006

Abstract
Various copper(I) complexes with monodentate imidazole(im) have been prepared from [Cu(CH3CN)4]X (X=ClO4− and PF6−) in acetone. Their characterization has principally been made by 1H NMR spectroscopy. Binary copper(I) complexes are [Cu(im)2]+ (2) and [Cu(im)3]+ (3), while the monoimidazole complex is a ternary two- or four-coordinate complex (1). In contrast with 2 and 3, quantitative formation of [Cu(im)4]+ (4) does not occur in acetone. Even at [im]/[Cu]&lt;2, 2 forms more preferentially than 1. This is due to the linear structure of 2. 2 and 3 provide stable CO adducts, both of which display complete reversibility. The affinity for CO of 3 is much stronger than that of 2. Pyrazole copper(I) complexes were also prepared and examined as a comparison with imidazole complexes. Monodentate pyrazole hardly gives two- and three-coordinate complexes. This is attributable to its low basicity in contrast with that of imidazole.
Preparation of Cubic HZr2(PO4)3 and Related Compounds
Authors: Ono Akira , Yajima Yoshiyuki 
Published: July 2006

Abstract
A single phase of cubic NH4Zr2(PO4)3 with a langbeinite-type structure was prepared at 235 °C by a hydrothermal method. A series of analogous compounds containing various monovalent cations or vacancies were made by starting with cubic NH4Zr2(PO4)3. They are polymorphs with respect to Nasicon-type compounds and have rigid skeleton structures with interstitial spaces partially occupied by monovalent ions and water molecules. Maximum water contents of the cubic compounds decrease with increasing sizes of the monovalent ions. Proton-bearing cubic compound exhibited ion exchange reactions with NaCl and LiCl solutions at 20 °C. This suggests the existence of bottlenecks large enough for permitting diffusion of Na+ and Li+ ions. Low thermal expansion of cubic NaZr2(PO4)3 was studied by high-temperature X-ray diffraction.
Green and Brown Isomers of the ((S)-1-Amino-2-propanethiolato-N,S)(1,4,7,10-tetraazacyclododecane)cobalt(III) Ion and Crystal Structure of the Green Isomer
Authors: Kojima Masaaki , Nakabayashi Kyoko , Ohba Shigeru , Okumoto Satoshi , Saito Yoshihiko , Fujita Junnosuke 
Published: July 2006

Abstract
The [Co(S-apS)(cyclen)]2+ (S-apS=(S)-1-amino-2-propanethiolate ion, cyclen=1,4,7,10-tetraazacyclododecane) complex was prepared and separated into two isomers (green and brown) by column chromatography. The crystal structure of the green isomer, [Co(S-apS)(cyclen)]ZnCl4·H2O was determined by X-ray analysis. Crystal data are as follows: monoclinic, space group P21, a=9.382(2), b=13.124(3), c=8.934(2) Å, β=91.08(3)°, and Z=2. The complex ion has a cis-octahedral geometry with the cyclen ligand coordinated in a folded, butterfly-like configuration and the bidentate S-apS ligand in a δ-gauche form. One of the two “planar” NH hydrogens of the macrocycle with respect to the S-apS ligand is directed opposite the S-apS chelate ring (exo), while the other “planar” and the remaining two “apical” NH hydrogens are directed to the S-apS ring (endo). The green isomer can be represented by endo(S,NH), where NH denotes the planar NH hydrogen cis to the sulfur atom. The other brown isomer was assigned as the exo(S,NH) configuration, where the S and NH2 coordination sites of S-apS in the green isomer are interchanged with each other, remaining the configuration of the macrocycle unchanged. Reversible isomerization between the two isomers occurred in aqueous solution and the kinetics was studied at 25.4 °C in the pH range of 5.98–6.97. The isomerization obeyed a rate law of the form, R=k[OH−]·[complex], and was suggested to take place with synchronous inversion at the two nitrogen atoms of the macrocycle. The relative abundance of the two isomers at equilibrium is 1.0, and the forward and reverse second-order rate constants at 25.4 °C are 6.5×103 mol−1 dm3 s−1.
Reaction of Carbocations Derived from Alkanes with Carbon Monoxide in HF–SbF5 Superacid
Authors: Yoneda Norihiko , Takahashi Yukio , Fukuhara Tsuyoshi , Suzuki Akira 
Published: July 2006

Abstract
Alkanes readily react with CO and H2O in HF–SbF5 at 30 °C under atmospheric pressure and give considerably different product distributions from those in the usual Koch–Haaf reaction. When using C5-or C6-alkanes with tertiary C–H bonds, a considerable amount of secondary carboxylic acids are produced by the reaction of CO with secondary alkyl cations. Such cations may appear as transient intermediates in the course of the carbon skeletal isomerization of initially formed tertiary cations. For the straight-chain alkanes, the protonolysis at C–C bonds initiated the reaction to give fragment alkyl cations. This resulted in the formation of carboxylic acids with a lower number of carbon atoms than the starting alkanes. Intermolecular hydride shift between the fragment cations and the starting alkanes occurred at the same time to form a large amount of carboxylic acids with the alkyl group of the same number of carbon atoms as the starting alkane. On the other hand, for alkanes with more than seven carbon atoms, β-scission occurs exclusively to produce C4–, C5–, and C6–carboxylic acids.
Synthesis of Vinylcyclopropanes, Cyclopropyl Vinyl Ketones, and 3-Pyrazolyl Vinyl Ketones from 1-Diazo-3-trimethylsilylpropanone
Authors: Tsuge Otohiko , Kanemasa Shuji , Suzuki Toshiro , Matsuda Koyo 
Published: July 2006

Abstract
Reaction of 1-diazo-3-trimethylsilylpropanone with olefins in the presence of cupric acetylacetonate (Cu(acac)2) affords cyclopropyl trimethylsilylmethyl ketones. One-flask procedure for the formation of these silylated ketones and subsequent treatment with organometallics or with lithium diisopropylamide (LDA) and then carbonyl compounds gives a variety of vinylcyclopropanes or cyclopropyl vinyl ketones in good yields, respectively. Cycloaddition of 1-diazo-3-trimethylsilylpropanone with acetylenes and similar carbon–carbon bond formation at the side chain of the cycloadducts lead to 3-pyrazolyl vinyl ketones.
The Stereochemistry of the Reduction of Carbon–Carbon Double Bond with the Cultured Cells of Nicotiana tabacum
Authors: Suga Takayuki , Hirata Toshifumi , Hamada Hiroki 
Published: July 2006

Abstract
The stereochemistry in the reduction of the C–C double bond adjacent to the carbonyl group with the cultured cells of Nicotiana tabacum was investigated by feeding (4R)-[6-2H]-(−)-carvone to the cultured cells. It was found that the hydrogen attack to the C–C double bond takes place stereospecifically from the si-face at C-1 and the re-face at C-6, being trans-addition.
Phenolic Solvent-Assisted Hydrogenolysis of trans-Stilbene
Authors: Mizuki Tatsuro , Futamura Shigeru , Kamiya Yoshio 
Published: July 2006

Abstract
Phenolic solvents such as phenol, 3,4-xylenol, 2-naphthol, and 5,6,7,8-tetrahydro-2-naphthol greatly promote toluene formation in the hydrogenolysis of trans-stilbene, compared with hydroaromatic hydrocarbon solvents. Toluene is afforded in the thermal decomposition of the phenolic solvent adduct to trans-stilbene, not via bibenzyl.
A 14N NMR Relaxation Study of Aqueous Alkyltrimethylammonium Salt Solutions
Authors: Uzu Yuhei , Nakagawa Jiro , Yokoi Masatoki 
Published: July 2006

Abstract
14N spin–lattice and spin–spin relaxation times were measured in a series of alkyltrimethylammonium salts at higher concentrations above the critical micell concentration. Octyltrimethylammonium bromide and dodecyltrimethylammonium chloride form spherical micelles at all concentrations, while decyl- and dodecyltrimethylammonium bromides form larger and rodlike micelles such as the hexadecyltrimethylammonium bromide suggested previously.
Optical Spectra of Tocopheroxyl Model Radicals
Authors: Mukai Kazuo , Watanabe Yoshiko , Ishizu Kazuhiko 
Published: July 2006

Abstract
Tocopheroxyl model radicals have been prepared by the reaction between tocopherol models and stable phenoxyl radical in ethanol under nitrogen atmosphere. Optical spectra were recorded, and wavelength of absorption peaks (λmax) and molar extinction coefficients (ε) were correctly determined.
Thermal Isomerization Equilibrium between 2′-Hydroxychalcones and Flavanones
Authors: Hoshino Yukio , Takeno Noboru 
Published: July 2006

Abstract
Nine substituted 2′-hydroxychalcones and the corresponding flavanones were heated separately at 230±0.2 °C in nitrogen atmosphere. Both materials were mutually isomerized under these reaction conditions and the equilibrium constants of this isomerization were measured by means of HPLC analyses. The substituent effect on the equilibrium is discussed and thermodynamic functions (ΔG, ΔH, and ΔS) are calculated.
Flow Injection Analysis of Cobalt(II) by Catalytic Oxidations of Stilbazo and Pyrocatechol Violet
Authors: Deguchi Toshio , Higashi Atsuya , Sanemasa Isao 
Published: July 2006

Abstract
Catalytic oxidations of ten organic dyes with an aromatic-hydroxyl or -amino functional group have been studied in the presence of metal ions such as cobalt(II), copper(II), and vanadium(V). Of these dyes, six were found to be effectively oxidized and decolorized specifically by one of these metals. 4,4′-Bis(3,4-dihydroxyphenylazo)stilbene-2,2′-disulfonic acid diammonium salt (Stilbazo) and 3,3′,4′-trihydroxyfuchsone-2″-sulfonic acid (Pyrocatechol Violet) were found to be promising for determining trace amounts of cobalt(II). The optimum analytical conditions have been studied for these two compounds with the aid of a flow injection analysis technique. The both reagents can be used to determine cobalt(II) down to 1 ppb.
Synthesis of 2,3-Dihydro-2-alkyl-3-(substituted amino)-1H-isoindol-1-ones. 2-Alkylation of 2,3-Dihydro-3-(substituted amino)-1H-isoindol-1-ones in a Phase-Transfer Catalyst System
Authors: Sato Ryu , Senzaki Toshihide , Goto Takehiko , Saito Minoru 
Published: July 2006

Abstract
A variety of 2,3-dihydro-2-alkyl-3-(substituted amino)-1H-isoindol-1-ones were conveniently synthesized by selective 2-alkylation of 2,3-dihydro-3-(substituted amino)-1H-isoindol-1-ones, which were derived from 2-cyanobenzaldehyde, with some alkyl halides in a phase-transfer catalyst system.
The Crystal and Molecular Structures of Bis(ethylenedithio)tetrathiafulvalene
Authors: Kobayashi Hayao , Kobayashi Akiko , Sasaki Yukiyoshi , Saito Gunzi , Inokuchi Hiroo 
Published: July 2006

Abstract
The X-ray crystal structure analysis of a sulfur containing π-donor molecule, bis(ethylenedithio)tetrathiafulvalene, (BEDT-TTF) shows that the BEDT-TTF molecule is nonplanar and that the crystal is composed of pairs of BEDT-TTF.
Reaction of Hydroxide Ion with Electron Acceptors in Dimethyl Sulfoxide
Authors: Umemoto Kisaburo , Okamura Nobuyuki 
Published: July 2006

Abstract
In dimethyl sulfoxide, the reaction of hydroxide ion with several electron acceptors—iodine, tetracyanoquinodimethan, Nitro Blue Tetrazolium chloride, 2,3,5-triphenyltetrazolium chloride, anthraquinone, and benzophenone—gave reaction products identical to those obtained by the reaction of these electron acceptors with electron donors. The reaction pathways of these electron acceptors were found to be composed of successive one-electron reactions similar to the electrochemical reduction of these electron acceptors. These results indicate that hydroxide ion acts as a reductant in dimethyl sulfoxide.
Ylide–Metal Complexes. XI. The Preparation and Properties of VIA Group Metal (Te) Complexes of Alkylidenetriphenylphosphoranes and the Corresponding Selenium Compounds
Authors: Yamamoto Yoshihisa 
Published: July 2006

Abstract
Reactions of (C6H5)3P=CH2 (L) with TeCl4 of mole ratios 2 : 1 and 3 : 1 yield new compounds: dichlorobis(methylenetriphenylphosphorane)tellurium dichloride, [L2TeCl2]Cl2 (1), and chlorotris(methylenetriphenylphosphorane)tellurium trichloride, [L3TeCl]Cl3 (2), respectively. The reaction of ylide L with compound 1 yields a new compound: tetrakis(methylenetriphenylphosphorane)tellurium tetrachloride, [L4Te]Cl4 (3). The structure of compounds 1–3 is a distorted tetrahedron. The color of 1–3 is yellow. The electronic absorption spectra of compounds 2 and 2 show six absorption bands in the region 200–500 nm in dry dichloromethane. The reactions of ylide L with (C6H5)2SeCl2 of mole ratios 1 : 1 and 2 : 1 yield new compounds: chloro(methylenetriphenylphosphorane)diphenylselenium chloride, [LSe(Cl)(C6H5)2]Cl (9), and bis(methylenetriphenylphosphorane)diphenylselenium dichloride, [L2Se(C6H5)2]Cl2 (11), respectively. The color of the selenium compounds is white. The tellurium and selenium compounds are thermally stable in the solid state.
The Crystal Structure of a Squarylium Dye, 2,4-Bis(1,3,3-trimethyl-2-indolinylidenemethyl)cyclobutenediylium-1,3-diolate
Authors: Kobayashi Yoshinori , Goto Midori , Kurahashi Masayasu 
Published: July 2006

Abstract
The crystal structure of 2,4-bis(1,3,3-trimethyl-2-indolinylidenemethyl)cyclobutenediylium-1,3-diolate has been determined. The space group is P21⁄c, with a=9.5115(4), b=15.712(1), c=15.174(1) Å, β=96.138(5)°, and Z=4. The molecule adopts the trans conformation.
Highly Enantioselective Reduction of Ethyl 2-Acyloxy-3-oxobutanoate with Immobilized Baker’s Yeast
Authors: Sakai Takashi , Nakamura Toshiki , Fukuda Katsuyoshi , Amano Eiichiro , Utaka Masanori , Takeda Akira 
Published: July 2006

Abstract
Reduction of ethyl 2-acetoxy-3-oxobutanoate (4a) with immobilized baker’s yeast in calcium alginate gel gave a 18 : 19 : 63 mixture of ethyl (2R,3S)- and (2S,3S)-2-acetoxy-3-hydroxybutanoates and ethyl (2S,3S)-2,3-dihydroxybutanoate each with &gt;95% e.e. in 58% yield. A similar treatment of a 2-benzoyloxy analog of 4a afforded a 6 : 94 mixture of ethyl (2R,3S)- and (2S,3S)-2-benzoyloxy-3-hydroxybutanoates (&gt;95% e.e.) in 70% yield. Their absolute configurations were determined by comparison with authentic (2R,3S)- and (2S,3S)-2,3-dihydroxybutanoic acids. Effects of the immobilization and the pH of culture solution on the product ratio are also discussed.
The High Pressure Diels–Alder Reactions of 5-Methoxy-2-methyl-4-(p-nitrophenyl)oxazole with Ethylenic Dienophiles
Authors: Ibata Toshikazu , Nakawa Hiroyuki , Isogami Yasushi , Matsumoto Kiyoshi 
Published: July 2006

Abstract
The high pressure Diels–Alder reactions of 5-methoxy-2-methyl-4-(p-nitrophenyl)oxazole with ethylenic dienophiles such as N-methylmaleimide, N-phenylmaleimide, dimethyl maleate and dimethyl fumarate gave the corresponding adducts in good to excellent yields. The effects of pressure, temperature, solvents on the yields were investigated. The high pressure also increased the formation of 3-hydroxypyridine derivatives via the elimination of methanol from the adducts. The stereospecificity of the reaction was confirmed for the reactions with maleate and fumarate.
Preparation of Optically Active Piperazines from Ethyl (S)-2-(2-Alkyl-1-aziridinyl)acetates
Authors: Yahiro Nobuhide , Ito Shigekazu 
Published: July 2006

Abstract
Reaction of ethyl (S)-2-(2-alkyl-1-aziridinyl) acetates with boron trifluoride etherate in a large excess of ethylamine or ammonia gives the corresponding optically active piperazines in good yields. These piperazines retain the configuration of the starting aziridines.