bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Efficient Method for the Direct Peroxygenation of Various Olefinic Compounds with Molecular Oxygen and Triethylsilane Catalyzed by a Cobalt(II) Complex
Authors: Isayama Shigeru 
Published: July 2006

Abstract
An efficient method for the direct peroxygenation of various olefinic compounds with molecular oxygen and triethylsilane (Et3SiH) was developed by the use of a catalytic amount of a bis(1,3-diketonato)cobalt(II) complex. According to the above method, 1-phenyl-3-triethylsilydioxybutane (2) was directly produced from 4-phenyl-1-butene (1) by means of a reaction with O2 and Et3SiH at room temperature. Styrene (3) and ethyl acrylate (5a) were also smoothly peroxygenated to give 1-phenyl-1-triethylsilyldioxyethane (4) and ethyl 2-triethylsilyldioxypropionate (6a) by using a small amount of t-BuOOH as an initiator. The successive desilylation of 6a and reduction of the resulting ethyl 2-hydroperoxypropionate (8a) afforded the corresponding alcohol, ethyl lactate (10a), in a high yield. The synthetic utility of the present peroxygenation reaction was demonstrated in the preparation of α-hydroxy esters 10a–e from several α,β-unsaturated esters 5a–e via the corresponding triethylsilyldioxy derivatives.
The Stereochemistry and Reactivity of Metal-Schiff Base Complexes. VII. Contribution of Hydrophobic Interligand Interaction to Chiral Recognition of Phenylalaninate and Tryptophanate with (1R,2R)-N,N′-Disalicylidene-1,2-cyclohexanediaminecobalt(III) Complex
Authors: Fujii Yuki , Yoshikawa Yuzo , Syoji Masato , Shinohara Homare 
Published: July 2006

Abstract
The stability constants, K1, of Δ-β2-diastereomers of mixed ligand cobalt(III) complexes with a chiral quadridentate Schiff base (sal-(R,R)-chxn), derived from salicylaldehyde and (R,R)-1,2-cyclohexanediamine, and d- or l-amino acidate (aa−=gly, ala, val, leu, thr, phe, trp, pro, asp, asn, and glu) were determined spectrophotometrically in water–methanol (2:3 by volume) containing acetate buffer (0.3 mol dm−3) at 22°C: trans-[Co{sal-(R,R)-chxn}(H2O)2]++aa−\oversetK1\ightleftharpoonsΔ-β2-[Co{sal-(R,R)-chxn}(aa)]. The K1 values range from 5.6×106 to 1.2×109 mol−1 dm3 and obey a linear free energy relationship except for d-phe, d-trp, d-asp, d-asn, and d-pro. In the cases of d-phe, d-trp, d-asp, and d-asn, their stability constants are 5–30 times as high as those for the corresponding l-aa. Extraordinary stabilization of the d-phe and d-trp complexes is discussed in terms of the interligand stacking of the aromatic rings between the Schiff base ligand and a side chain of amino acidate on the basis of conformational analysis and 1H NMR spectra.
Physical Properties of 3-Propylsydnone
Authors: Sasaki Yukio , Ishibashi Yoshimoto 
Published: July 2006

Abstract
The physical properties of 3-propylsydnone at various temperatures were investigated by dielectric constant, refractive index, density and viscosity measurements. The dielectric constant (ε) of 3-propylsydnone is very high compared to those of many organic solvents. For example, this value was found to be 95.0 at 25 °C. The dielectric constant of 3-propylsydnone is approximately expressed by a cubic equation of the temperature. The Kirkwood equation holds over the range from 10 to 150 °C. The refractive index (nD) and density (ρ) data for 3-propylsydnone are described as linear equations of the temperature with maximum deviations of 0.008 and 0.005%, respectively. The viscosity (η) of 3-propylsydnone at 25 °C is 8.45 cP (1 cP=10−3 N s m−2). This value is larger than those of many organic solvents, but smaller than those of sulfolane and 1,2-ethanediol. A plot of logη vs. 1/T for 3-propylsydnone yields a straight line. The activation energy of the viscosity for 3-propylsydnone was found to be 25.0 kJ mol−1.
The Electroxidation of Methanol in the Potential Region of Platinum–Oxygen Layer
Authors: Matsui Hiroshi , Kunugi Akira 
Published: July 2006

Abstract
Methanol oxidation at a platinum electrode in 0.5 mol dm−3 sulfuric acid at high potentials was retarded by the formation of both an oxygen layer and a new type of retarding substance from methanol. The presence of the retarding substance was confirmed by the oxygen-deposition method. During retardation due to the formation of an oxygen layer, the rate of methanol oxidation both decreased and increased with increasing oxygen coverage and potential, respectively. The reverse efcets of oxygen coverage and potential concurrently occurred when the potential was a variable. At low oxygen coverage, the decreased effect of oxygen coverage was more remarkable than the increased effect of the potential, while the order of the remarkableness was reversed at middle coverage. The reversal of the order could be explained in terms of a catalytic reduction of the oxygen layer with methanol.
Covalent Immobilization of Ultrafine Platinum Particles onto Crosslinked Polymer Support and Their Application to Catalysis
Authors: Ohtaki Michitaka , Toshima Naoki , Komiyama Makoto , Hirai Hidefumi 
Published: July 2006

Abstract
Ultrafine particles of platinum were prepared as stable aqueous dispersions by a photoreduction method in the presence of soluble protective polymers. By use of the protective polymer with methyl acrylate residues as a reactive group, the polymer-protected ultrafine platinum particles were successfully immobilized onto crosslinked polymer supports with amino groups. The present immobilization was attributed to the formation of amide bonds by the reaction of methyl acrylate residues in the protective polymer with amino groups in the support, and the immobilization mechanism was investigated by the model reaction using protective polymer with p-nitrophenyl acrylate residues as a reactive group. The immobilized platinum particles obtained show high catalytic activity for hydrogenation of olefins and specific substrate selectivity due to a hydrophilic–hydrophobic interaction between the support and the substrate.
Apparent Molar Volume and Viscosity of N-Methylpyridinium Iodide and Its Methyl-Substituted Derivatives in Water
Authors: Swain R K , Tiwary L K , Behera B 
Published: July 2006

Abstract
The apparent molar volume and the viscosities of N-methylpyridinium iodide and its methyl derivatives in water at 25, 30, 35, and 40 °C are reported. The apparent molar volumes obey Masson’s equation. The φv° and Sv* values indicate strong ion–ion interaction in water. φv° is linearly related to temperature. The relative viscosity data of these salts obey Jones–Dole and Vand equations well. The A and B values of Jones–Dole equation and Q values of Vand equation suggest greater solvation in case of NMPI and the β-CH3 salt and greater ion–ion interaction in case of α-CH3 and γ-CH3 salts. The data have been discussed in terms of hydrophobic hydration and solvent shared ion pairs. The free energy of activation for viscous flow are almost equal for these salts. The importance of A, B, B+, and Q to the study of the solvent structure is discussed.
Coordination Chemistry of Proton. In Situ Synthesis and X-Ray Structural Analysis of 2-Hydroxyethanaminium Picrate, HOCH2CH2NH3+·C6H2N3O7−
Authors: Poonia Narinder S , Chandra Ramesh , Sheldrick W S 
Published: July 2006

Abstract
2-Hydroxyethanaminium picrate, HOCH2CH2NH3+·C6H2N3O7−, is prepared through a metathetical reaction of Mg(Pic)2 and HOCH2CH2NH2 (2-aminoethanol, MEA) in ethanol through in situ generation of HPic. Orange yellow crystals (MEAH+Pic−) (mp 163°C) of the “Salt” are produced alongwith the colorless Mg(CH2NH2CH2O−)2, even when MEA is less than 1:1 with respect to Mg(Pic)2. The crystals are monoclinic, space group P21/c, a=11.797(4), b=14.288(3), c=7.124(2) Å, β=97.63(2)°, Z=4, Dcal=1.62 g cm−3. Structural analysis from the 1617 reflection data (R=0.059, Rw=0.056) reveals that the picric acid proton is formally transferred to the MEA nitrogen (N–H, 0.968 Å) and is merely bonded to the phenoxide of Pic (H···O−, 1.951 Å) and weakly also to an oxygen of o-nitro group of the anion (H···ONO, 2.379 Å). The transferred proton becomes an integral part of the cation MEAH+ and completes the fourth covalent bond of the sp3 N of MEA, and does not show any special affinity for the anionic oxygen of Pic; the N–H···O− (142.8°) and N–H···ONO (141.6°) angles are closely comparable.
Creatones A and B. Revision of the Structure for the Product of Oxidation of Creatinine and Creatine
Authors: Nakamura Ko , Ohira Chikara , Yamamoto Hiroshi , Pfleiderer Wolfgang , Ienaga Kazuharu 
Published: July 2006

Abstract
The structure for a product of the oxidation of creatinine is revised to be N-(N′-methylamidino)oxamic acid (4). Acyclic product 4 and its cyclic product, 2-amino-1-methyl-4,5-imidazoledione, are coined as creatones B and A, respectively. The first synthesis of 2-methylamino-4,5-imidazoledione is also described.
Reaction of 2-Chlorocyclohepta[b]pyrrole-3-carbaldehyde with o-Phenylenediamine
Authors: Abe Noritaka , Emoto Yoshifumi 
Published: July 2006

Abstract
Reaction of 2-chlorocyclohepta[b]pyrrole-3-carbaldehyde with o-phenylenediamine gave 1H-2-(2-chlorocyclohepta[b]pyrrol-3-yl) benzimidazole (3a) and 5H-12,13-dihydrocyclohepta[1′,2′:4,5]pyrrolo[2,3-b][1,5]benzodiazepine (4a). Some reactions of 3a and 4a were also described.
Formation Mechanism of the Complexes between DMSO and Halogen Atoms. II. Laser Flash Photolysis Studies
Authors: Sumiyoshi Takashi , Watanabe Kazuyuki , Syogen Satoshi , Kawasaki Masahiro , Katayama Meiseki 
Published: July 2006

Abstract
The laser flash photolysis of DMSO/CCl4 mixed solutions produces the transient DMSO–Cl complex with an absorption maximum at 400 nm. The formation of the complex has been explained by the direct photoexcitation of the ground state associated DMSO/CCl4 pair on the basis of the spectroscopic data and the known macroscopic physical properties of binary solutions of DMSO and CCl4.
Synthesis and Square Planar-Octahedral Equilibrium of Bismacrocyclic Dinickel(II) Complexes with Polymethylene Bridges of Various Lengths
Authors: Mochizuki Katsura , Ikeda Yosihito 
Published: July 2006

Abstract
A new series of binuclear nickel(II) complexes with bis(tetraazamacrocycle), 7,7′-polymethylenebis[3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15-triene]dinickel(II) perchlorates with polymethylene bridges with a length of 2–6-C, was synthesized, as well as the corresponding free ligands. The dinickel(II) complexes were found to be in equilibrium between square planar and octahedral forms in water. The equilibrium shifts toward the octahedral side as the polymethylene bridge becomes short.
Oxidation of Coals in Liquid Phases. X. Mechanism of the Cleavage of Benzenecarboxylic Acids to Oxalic Acid and Carbon Dioxide by the Base-Catalyzed Oxygen-Oxidation
Authors: Ichinose Shuji , Okuwaki Akitsugu 
Published: July 2006

Abstract
A kinetic study of the oxidation of benzenecarboxylic acids has been performed in order to clarify the mechanism. The reaction products were oxalic acid and carbon dioxide, along with a trace of acetic acid. The oxidation rate of phthalic acid was proportional to the first order of the molality of phthalic acid, the molality of NaOH, and partial oxygen pressure, respectively; the apparent activation energy was 126 kJ mol−1. These results show that the rate-determining step is a cleavage of the benzene ring proceeded by a base-catalyzed oxygen-oxidation mechanism in which a carbanion formed by hydrogen extraction from an aromatic ring is attacked by oxygen. In the cleavage of phthalic acid, NaOH increases the selectivity to form oxalic acid as well as the oxidation rate. In the oxidation of 1,2,3-benzenetricarboxylic acid the same mechanism was recognized, but not for benzenehexacarboxylic acid which has no hydrogen on the benzene ring.
Synthesis and Characterization of 18-Molybdopyrophosphate Complex
Authors: Himeno Sadayuki , Saito Atsuyoshi , Hori Toshitaka 
Published: July 2006

Abstract
The existence of a heteropoly 18-molybdopyrophosphate was ascertained in both solid and solution states. The yellow complex was formed in solutions of 0.05 M (M=mol dm−3) Mo(VI)/5×10−3 M pyrophosphate/0.1–0.7 M HCl/60% (v/v) CH3CN at ambient temperatures, being isolated as tetraalkylammonium (R4N+) salts where R=n-C4H9 and C2H5. The presence of organic solvents was essential for the preparation of the complex. The 18-molybdopyrophosphate complex underwent a four-step reduction in 95% (v/v) CH3CN–water containing 0.1 M HClO4, yielding mixed-valence blue species by the electrochemical reduction at the respective steps of a reversible two-electron transfer. The heteropoly skeleton is retained in the blue complexes. The UV-visible and IR spectroscopic characteristics, and the formation conditions of the 18-molybdopyrophosphate complex were also elucidated.
Adsorption of Cholesterol at Hexane/Water Interface
Authors: Matsuguchi Masanobu , Aratono Makoto , Motomura Kinsi 
Published: July 2006

Abstract
The interfacial tension between hexane solution of cholesterol and water was measured as a function of temperature and the mole fraction of cholesterol in hexane under atmospheric pressure. The interfacial tension vs. mole fraction of cholesterol curve was observed to have two break points at a certain temperature; the concentration of the break point increases with increasing temperature. The experimental results were analyzed by applying the rigorous thermodynamics of adsorption at interfaces developed previously. The excess number of moles of cholesterol and the thermodynamic quantity changes associated with its adsorption were found to show the discontinuous changes at the break points. It was concluded that the first-order phase transition takes place from the gaseous to the expanded state and from the expanded to the condensed one in the adsorbed film of cholesterol at the hexane/water interface.
Total Synthesis of (−)-Chiloscyphone, Sesquiterpenoid Isolated from the Liverwort. Absolute Configuration of (−)-Chiloscyphone and (+)-Chiloscypholone
Authors: Tori Motoo , Hasebe Takeshi , Asakawa Yoshinori 
Published: July 2006

Abstract
The absolute configurations of (−)-chiloscyphone and (+)-chiloscypholone isolated from the liverwort Chiloscyphus polyanthos and C. pallescens respectively, have been determined by the total synthesis of the optically active compound. The 1,4-addition of vinylmagnesium bromide to 3,4-dimethyl-2-cyclohexenone in the presence of copper(I) bromide-dimethyl sulfide complex and the subsequent aldol condensation of the ketoaldehyde derived in several steps afforded the hydrindenone derivative. The key intermediate alcohol has been resolved by the use of (1S)-(−)-camphanic chloride. The optically active hydroxy ester has been converted to (−)-chiloscyphone.
Electrochemical Polymerization of N-Trimethylsilylpyrrole and Other Substituted Pyrroles Which Contain Si or Ge Atom(s) in Their Monomer Structures
Authors: Okano Mitsutoshi , Toda Atsuko , Mochida Kunio 
Published: July 2006

Abstract
N-Trimethylsilylpyrrole and three new compounds; N-trimethylgermylpyrrole, N-chloromethyldimethylsilylpyrrole, and N-pentamethyldisilanylpyrrole, were synthesized. These four monomers were electrochemically polymerized and four new organic conducting polymers were obtained. Resulting polymers had good film producibility and conductivity as high as that for polypyrrole. They showed three distinguishable colors at different potentials: blue in the doped state, yellow in the undoped state, and reddish color in between.
Stereochemistry of NAD(P)-Coenzyme in the Reaction Catalyzed by Glycerol Dehydrogenase
Authors: Nakamura Kaoru , Shiraga Tsuyoshi , Miyai Takehiko , Ohno Atsuyoshi 
Published: July 2006

Abstract
The coenzyme stereospecificities in the reaction of glycerol dehydrogenases (GDH) from various microbial sources have been determined. It is found that the nicotinamide-coenzymes (NADH and NADPH) employed by GDHs from eucaryotes exert the pro-S specificity, whereas those employed by procaryotes exert the pro-R specificity. The stereospecificity of the coenzyme seems to have a correlation with chemical evolution of GDH as well as biological evolution of the host organism.
A Grignard-Type Addition of Allyl Unit to Aldehydes by Using Bismuth and Bismuth Salt
Authors: Wada Makoto , Ohki Hidenori , Akiba Kin-ya 
Published: July 2006

Abstract
In the presence of metallic bismuth, bismuth(III) chloride–metallic zinc, or bismuth(III) chloride–metallic iron, allylic halides have been found to react with aldehydes under mild conditions to give the corresponding homoallylic alcohols in high yields with high chemo-, regio-, and stereoselectivity. Allylic halides have been also found to react with aldehydes at room temperature in tetrahydrofuran–water by using bismuth(III) chloride–metallic aluminium to afford the expected homoallylic alcohols in high yields.
Kinetic Study on the Alkaline Hydrolysis of S,S-Diaryl-N-halosulfilimines
Authors: Yoshimura Toshiaki , Tsukurimichi Eiichi , Kita Hiroshi , Fujii Hiroshi , Shimasaki Choichiro 
Published: July 2006

Abstract
Kinetics for the alkaline hydrolysis of S,S-diaryl-N-bromosulfilimines were carried out in aqueous methanol. The observed pseudo-first-order rate constants were found to give a linear correlation with the concentration of sodium hydroxide, k=k1+k2[NaOH]. The first-order rate constants k1 showed a large negative Hammett ρ value (−2.43) for the substituent effect on the phenyl group, nearly zero activation entropy (−0.9±13.1 JK−1mol−1) and a relatively large m value (0.638) against the solvent ionizing power Y value suggesting that the reaction process for k1 close to SNl. The salt effect, the deuterium solvent isotope effect and the steric effect are also in accord with the SNl mechanism. On the other hand, the second-order rate constants k2 revealed a small Hammett ρ value, a negative activation entropy (−44.0±4.0 JK−1mol−1), a small m value (0.153) and a steric deceleration by ortho substituents showing that the reaction for k2 is SN2-like. The salt effect and the solvent isotope effect are also compatible with the SN2-like mechanism. Meanwhile, the k1 for S,S-diphenyl-N-halosulfilimines remarkably increased in the order of N-iodo&lt;N-bromo&lt;N-chloro. This reactivity might be due to the lone pair-lone pair repulsion at the reactant state. From these observations, the alkaline hydrolysis of S,S-diaryl-N-halosulfilimines was confirmed to proceed via concurrent two mechanisms, the SN2′-like mechanism involving nitridosulfonium cation (&gt;+S≡N) as an intermediate and the SN2′-like mechanism with the transition state in which the N-X bond cleavage is more progressed than the S–O bond formation with nucleophiles (−OH, −OMe).
DABCO-Mediated Synthesis and Biological Activity of Cyanohydrin Esters
Authors: Hoffmann H M R , Ismail Z M , Hollweg Reiner , Zein Abdul R 
Published: July 2006

Abstract
Cyanohydrin esters 1–31 have been prepared from α-ketonitriles and aldehydes using DABCO (1,4-diazabicyclo[2.2.2] octane) as nucleophilic acylation catalyst. The modified piperonal 8 was found to inhibit the formation of thromboxane synthetase.
The Dissociation Equilibrium of the Copper(II) Acetate Dimer in Acetic Acid
Authors: Kikuchi Yoichi , Suzuki Toshio , Sawada Kiyoshi 
Published: July 2006

Abstract
The dissociation equilibrium of the copper(II) acetate dimer in acetic acid was studied by means of high-sensitivity spectorophotometry. The dissociation constant of the nonaquated dimer was determined to be Kdis=10−6.2±0.2 at 25 °C. The dissociation was promoted in the presence of water. The formation constant of the monoaquated monomer was estimated to be Kml=3.0.
Synthetic Study on Peptide Antibiotic Nisin. III. Synthesis of Ring C
Authors: Fukase Koichi , Kitazawa Manabu , Wakamiya Tateaki , Shiba Tetsuo 
Published: July 2006

Abstract
A cyclic sulfide moiety corresponding to ring C in peptide antibiotic nisin was successfully synthesized from a disulfide compound prepared from a heptapeptide involving l-cysteine and threo-3-methyl-d-cysteine through desulfurization reaction with hexaethylphosphorus triamide.
Structure for the “Biguaiazulene-3,3′-dione” and Efficient Preparation of 5-Isopropyl-3,8-dimethyl-1,7-azulenedione
Authors: Matsubara Yoshiharu , Morita Masanori , Matsui Shuichi , Takekuma Shin-ichi , Yamamoto Hiroshi , Ito Shunji , Morita Noboru , Asao Toyonobu , Nozoe Tetsuo 
Published: July 2006

Abstract
The dimeric compound formed from 3-guaiazulenol has been found to be identical with the main product (Q2) of the peracid oxidation of guaiazulene, thus the previous structure of Q2 being revised to be a ca. 1:1 mixture of meso (5R,5′S) and two enantiomeric (5R,5′R and 5S,5′S) forms of [5,5′-biguaiazulene]-3,3′(5H,5′H)-dione. Autoxidation of Q2 in pyridine at 25 °C for 1 d mainly gives the title 1,7-azulenedione.
Reactions of Cinnamylideneamino Isoxazoles with Dimethyl Acetylenedicarboxylate
Authors: Thirmal Rao Errabelli , Rajanarendar Eligeti , Krishnamurthy Ananthula 
Published: July 2006

Abstract
The interaction of 4-cinnamylideneamino-3-methyl-5-styrylisoxazoles (1) with dimethyl acetylenedicarboxylate has given an isoxazolyldihydropyridine (2) as major and an isoxazolylaminofumarate (3) as minor products respectively. 3-Cinnamylideneamino-5-methylisoxazoles (4) behave similarly. Isoxazolylaminofumarates (3 and 6) have been identified by unambiguous synthesis.
Studies on 5-8 Fused Ring Compounds. V. The Conformations of Eight-Membered Rings in 5-8-5 Fused Ring Compounds and Their cis-trans Isomerization
Authors: Umehara Misao , Hishida Shinzabro , Okuda Masami , Ohba Shigeru , Ito Masatoki , Saito Yoshihiko , Zen Shonosuke 
Published: July 2006

Abstract
The 5-8-5 fused ring compounds, synthesized by photocycloaddition, cis-cisoid-cis- and cis-transoid-cis-tricyclo[9.3.0.04,8]tetradecane-2,9-dione (1-A and 2-A) and cis-cisoid-cis-tricyclo[9.3.0.03,7]tetradecane-2,9-dione (3-A) were isomerized to trans isomers (1-B, 1-C, 2-B, 2-C, and 3-B) at ring junction under basic conditions. Their molecular structures except for 1-B were determined by X-ray crystallography. The eight-membered rings of these 5-8-5 fused ring compounds were found in various conformations, boat-chair, twist-boat (S4), chair, twist-boat-chair, and chair-chair forms. With regard to the conformations of their eight-membered rings the strain energies were calculated by MM2 and the predicted conformations were compared with those obtained by X-ray crystallography.
Effect of Supporting Carbon Particles on Electric and Electrochemical Properties of Polarizable Electrodes Using Activated Carbon Fiber Sheets in Electric Double Layer Capacitors
Authors: Tanahashi Ichiro , Yoshida Akihiko , Nishino Atsushi 
Published: July 2006

Abstract
The effect of supporting carbon particles on the electric and electrochemical properties of polarizable electrodes in electric double layer capacitors have been studied. The polarizable electrodes examined were activated carbon fiber sheets (ACF sheets) composed of phenolic resin-based activated carbon fibers, carbon fibers, and pulps. The sheets with supporting carbon particles have been prepared by impregnation of the sheets with suspension of submicron carbons. The electric resistance of the sheets with supporting carbon particles of 18.7 g m−2 decreased by 53% and the differential electric double layer capacitance in an organic electrolyte increased by 12%. In accordance with these results, the impedance of the capacitors composed of ACF sheets with supporting carbon particles decreased by 33% and the capacitance increased by 11% in comparison with those of the capacitors composed of the sheets without supporting ones.
Optical Resolution of Arsine Oxides by Complexation with Optically Active [1,1′-Binaphthyl]-2,2′-diol
Authors: Mori Koji , Toda Fumio 
Published: July 2006

Abstract
Some dialkylarylarsine oxides were resolved efficiently by complexation with optically active [1,1′-binaphthyl]-2,2′-diol.