bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereochemistry and Some Kinetic Aspects of Fluorination of Phenyl-Substituted Alkenes with SelectfluorTM Reagent F-TEDA-BF4
Authors: Stavber Stojan , Sotler-Pecan Tjaša , Zupan Marko 
Published: June 2006

Abstract
Reactions of phenyl-substituted alkenes with SelectfluorTM fluorinating reagent F-TEDA-BF4 in the presence of various alcohols resulted in the formation of vicinal fluoroalkoxy adducts with Markovnikov type of regioselectivity. The stereochemistry of the fluoro-methoxylation addition reaction was found to be slightly syn predominant in the case of (Z)-stilbene, indene, and dibenzosuberenone, while equal amounts of both diastereoisomers were formed in the case of (E)-1-phenyl-1-propene and acenaphthylene. In the phenyl-substituted benzocyclene series the stereochemistry of fluoro-alkoxylation was found to be dependent on ring size and on the structure of the alcohol. The resulting vicinal fluoroalkoxy adducts were transformed by heating in aqueous HBr to 2-fluoro-1-phenylbenzocyclenes. Correlation of the logarithms of relative rates of fluoro-methoxylation reactions in a series of ten α-phenyl and α,α-diphenyl acyclic and cyclic alkenes with the ionization potentials of these alkenes resulted in a linear relationship with a slope of −2.75. Correlation of log krel for the present reaction with those for the reaction of the same alkenes with CsSO4F or XeF2 yielded excellent linearity for the pair F-TEDA/CsSO4F and scarcely good one for the pair F-TEDA/XeF2. The Hammett correlation analysis of the reaction of substituted 1,1-diphenylethenes with F-TEDA in MeCN/MeOH solvent gave the reaction constant ρ+ of −1.42, so indicating a moderate electron deficiency on the reactive center in the rate-determining step of the reaction.
An Anion Receptor Based on Poly-Substituted Cobalticinium Complexes
Authors: Komatsuzaki Nobuko , Uno Mitsunari , Shirai Kazuhiko , Takai Yoshio , Tanaka Takanori , Sawada Masami , Takahashi Shigetoshi 
Published: June 2006

Abstract
Various derivatives of poly-substituted cobalticinium complexes have been synthesized by using substituted cyclopentadienes with a convertible carboxylic group. By 1H NMR titration experiments, these complexes were shown to behave as a receptor for anions such as Cl−, Br−, AcO−, and p-TsO−. Planar-chiral anilide derivative 3a showed chiral recognition toward camphor-10-sulfonate though the difference of the association constants was 10%. The molecular structure including the absolute configuration of 3a have been established by an X-ray crystallographic analysis. The results suggest the hydrophobic cavity constructed by the substituents on the cyclopentadienyl ligands may be an important component for the successful anion complexation.
Reactivities of Stable Rotamers XXXVII : Thermolyses and Photolyses of 2(1H)-Thioxo-1-pyridyl 3-(1,4-Dimethyl-9-triptycyl)-3-methylbutanoate Rotamers
Authors: Toyota Shinji , Oki Michinori 
Published: June 2006

Abstract
By decomposition of the title compounds, 2-(1,4-dimethyl-9-triptycyl)-2-methylpropyl radical rotamers were generated. In thermolysis the ap-isomer gave, as a main product, a cyclic compound which was formed by attack of the radical on the benzene ring in proximity, whereas extensive rearrangement took place to produce 1-substituted methyl derivatives in the case of sc. In photolysis, various out-of-cage products were found from both rotamers including dimers of radicals. The results are attributed to formation of high concentration of the radicals in photolyses. The product distributions are also affected by the phase, i. e. solution, melts, or solid, as well as temperature. Solid state photolyses afforded 2-pyridyl thioethers as almost exclusive products, suggesting that recombination of radicals in the cage is important under the conditions where movement of the radicals is restricted.
Lipase-Catalyzed Practical Synthesis of (R)-1-Benzyl-3-hydroxy-2,5-pyrrolidinedione and Its Related Compounds
Authors: Tomori Hiroshi , Shibutani Kuniko , Ogura Katsuyuki 
Published: June 2006

Abstract
A practical method for preparing (R)-1-benzyl-3-hydroxy-2,5-pyrrolidinedione (1) was investigated by the use of the enzymatic hydrolysis of its acetate (2a). Among several hydrolases examined here, lipase PS from Pseudomonas cepaciagave the best result: In a mixed solvent (1 : 1 v/v) of dioxane and a phosphate buffer (pH 7), the hydrolysis took place smoothly with a high enantioselectivity (E &gt; 3000). Several 3-alkanoyl derivatives of 1 were subjected to the lipase PS-catalyzed hydrolysis. The chain length of the alkanoyl does not noticeably influence the reaction rate or the enantioselectivity. In contrast, the hydrolysis of the 1-benzoyl derivative proceeded slowly with a low enantioselectivity (E = 19). The syntheses of optically active 3-hydroxypyrrolidines and 3-hydroxypiperidines were also achieved under the reaction conditions similar to the lipase PS-catalyzed hydrolysis of 2a.
Synthesis of 10-Cyanoverticillene and Its Reactions Directed toward the Verticillol Synthesis
Authors: Kato Tadahiro , Hirano Takumi , Hoshikawa Masahiro , Uyehara Tadao 
Published: June 2006

Abstract
Directed toward the synthesis of verticillols, 10-cyanoverticillene 8 was settled as a key intermediate. Bond formation of cyano chloride 7 possessing secoverticillane skeleton to the key intermediate 8 with LiN(TMS)2 at 60 °C proceeded smoothly with moderate yield. The tetrasubstituted double bond of 8 was selectively oxidized, providing the epoxyverticillene derivatives 15 and 16. Hydride reduction of the epoxides were attempted, giving unexpected results. Synthesis of dl-verticillene 13 was also presented.
Oxidative Coupling of Methane on MgO–MgSO4 Catalysts in the Presence and Absence of Carbon Tetrachloride
Authors: Sugiyama Shigeru , Miyamoto Takashi , Hayashi Hiromu , Moffat John B 
Published: June 2006

Abstract
The effect of carbon tetrachloride (CCl4) on the oxidative coupling of methane on binary catalysts containing MgO and MgSO4 was studied at 1048 K. With no CCl4 in the feedstream the conversion of methane increased with increasing content of MgO in the binary catalyst, but was even further enhanced by introducing a small partial pressure of CCl4. The selectivity to ethylene increased upon the addition of CCl4, but was not dependent on either the concentration of CCl4 in the feedstream or the relative amounts of the two components in the catalyst. X-Ray photoelectron spectroscopic analyses of the used catalysts showed that the sulfate is partially transformed into the oxide as well as the formation of Cl species in the near-surface region of the catalysts during the methane conversion process. The addition of CCl4 enhances the conversion of sulfate to oxide. The oxide formed by the decomposition of the sulfate and the chlorine species plays different roles in improving the catalytic activities by introducing CCl4.
Formation of Methanol by Microwave-Plasma Reduction of CO2 with H2O
Authors: Ihara Tatsuhiko , Ouro Takashi , Ochiai Tomoyuki , Kiboku Mitsuo , Iriyama Yu 
Published: June 2006

Abstract
Reduction of CO2 with H2O was carried out by microwave plasma for the formation of methanol. The results of steam chromatography and mass spectrometry showed that the plasma products contained methanol. The methanol formation was also found in H2O-plasma-cleaning process, in which materials which had been deposited in the reaction between CO2 and H2O were removed. The most adequate plasma energy density for the formation of methanol was found to be 0.26 GJ kg−1 of W/FM. The methanol yield at the system pressure of 400 Pa was 3.5 times higher than at 240 Pa for both the CO2–H2O synthetic process and the H2O-cleaning process.
Photophysical Properties and Photosubstitution and Photoredox Reactions of Aromatic Nitro Compounds
Authors: Nakagaki Ryoichi , Mutai Kiyoshi 
Published: June 2006

Abstract
Orientation rules for photochemical nucleophilic substitutions are deduced from intramolecular photoreactions of some bichromophoric chain molecules, p-O2NC6H4O(CH2)nNHC6H5. The lower homologues undergo photochemical nucleophilic substitutions which can be classified as a Smiles-type photorearrangement. The photochemistry of this type of bifunctional chain species depends upon the methylene chain length. When the chain length is sufficiently long, the photorearrangement is totally forbidden. Photoredox reactions are the only accessible reaction processes for the higher homologues. The photoredox reaction consisting of cage and escape pathways is modulated by an external magnetic field. The magnetic field effects on the end product distribution are due to changes in the intersystem crossing rate induced by hyperfine interaction within biradical intermediates.
Stereoselective Synthesis of Cyclopropanes via Homoallylic Participation
Authors: Nagasawa Tetsuya , Handa Yasuhiko , Onoguchi Yuka , Suzuki Keisuke 
Published: June 2006

Abstract
A facile method for synthesizing trans-disubstituted cyclopropanes is described. γ,γ-Dimethyl homoallyl alcohols, upon conversion to the corresponding triflate, undergo smooth cyclization to give cyclopropanes in a stereoselective manner (trans) and in a stereospecific manner (inversion of configuration at the chiral center). Various functionalities could be introduced at the α-position of the newly formed cyclopropane ring by treating the cyclization mixture with hetero as well as carbon nucleophiles. Alternatively, treatment of the reaction mixture with triethylamine effects the clean elimination of a triflic acid to give high yields of the cyclopropanes with a 2-propenyl group, which are convertible to the corresponding cyclopropyl methyl ketones by ozonolysis in high yields. Also described is an application of the method to a short-step synthesis of a cyclopropane-containing eicosanoid, related to marine prostanoid biosynthesis.
Increase of van der Waals Attractive Force under Electromagnetic Field
Authors: Kimura Keisaku 
Published: June 2006

Abstract
A formula for the photoincreased van der Waals attractive force is derived, which includes the effects of the frequency of illuminated electromagnetic waves and of the size of particles. The interparticle interaction energy as a function of the frequency of the electromagnetic wave shows a sharp maximum at the resonance frequency. In the small limit of the size, the van der Waals force under on-resonance irradiation conditions approaches that of molecules and in the large limit the force is drastically reduced. The largest interparticle interaction is found at the size of a few tens of nm. This novel effect is found to be typical of nano-systems.
Mass Spectrometric Investigation of the Vapor over the LnCl3–KCl Equimolar Melt (Ln = Nd, Er) at High Temperatures
Authors: Murase Kuniaki , Adachi Gin-ya , Hashimoto Masashi , Kudo Hiroshi 
Published: June 2006

Abstract
Vaporization of the LnCl3–KCl (Ln = Nd and/or Er) equimolar molten mixture was investigated at 1018—1273 K by means of Knudsen effusion mass spectrometry. The vapor species KCl, K2Cl2, NdCl3, and KLnCl4 were found in the vapor over the melt, and their vapor pressures were evaluated for the NdCl3–KCl system. Volatility enhancement of NdCl3 by the formation of the vapor complex KNdCl4 decreases with increase in temperature. A relatively small enthalpy change, −10 ± 21 kJ mol−1, of the isomolecular exchange KNdCl4(g) + KCl(g) = NdCl3(g) + K2Cl2(g) suggests that the structural change of the reaction is not drastic and that the KNdCl4(g) complex has two bridging and two terminal chlorine atoms.
Coordination Asymmetry of a Dinuclear Copper(II) Complex: Synthesis, Structure, and Magnetism
Authors: Kayatani Takayuki , Hayashi Yoshihito , Suzuki Masatatsu , Inomata Katsuhiko , Uehara Akira 
Published: June 2006

Abstract
A dicopper(II) complex with a novel unsymmetric dinucleating ligand, H2L-1, which can provide donor atom, coordination number, and geometric asymmetries at metal centers, [Cu2(L-1)(CH3COO)]ClO4·H2O·0.5NaClO4 (1), was synthesized, where H2L-1 is a racemic 1-bis(2-pyridylmethyl)amino-3-salicylideneaminopropan-2-ol. The ligand is a hybrid one of 1,3-bis[bis(2-pyridylmethyl)amino]propan-2-ol (Htpdp) and 1,3-bis(salicylideneamino)propan-2-ol (H3L-2). Crystal structure of 1 was determined by X-ray crystallography. Complex 1 crystallizes in monoclinic space group C2/c with a = 42.704(8), b = 12.689(6), c = 29.008(9) Å, β = 128.28(1)°, and Z = 16. The crystal structure showed that two stereoisomers (1a and 1b) are present in solid state. This is attributable to the presence of an enantiomeric pair of L-1. Dinuclear cations consist of one square-planar site with a NO3 donor set and one five-coordinate site with a N3O2 donor set, which are linked by an endogenous alkoxide bridge of L-1 and an exogenous acetate bridge. A powdered sample of 1 shows weak antiferromagnetic interaction (2.60 B.M./Cu2 at 300 and 1.81 B.M./Cu2 at 5 K). Cryomagnetic data is analyzed using two exchange coupling constants, J1 = −0.18 cm−1 and J2 = −9.05 cm−1. EHMO calculations revealed that the observed weak antiferromagnetic interaction(s) compared with that found for [Cu2(L-2)(CH3COO)] (3) (J = −85 cm−1) is reasonably interpreted in terms of the energy gap and the nature of HOMO and LUMO. Some other physicochemical properties of the complex are discussed in comparison with those of the parent complexes, [Cu2(tpdp)(CH3COO)]2+ (2) and [Cu2(L-2)(CH3COO)] (3).
Synthesis and Characterization of Dinuclear and Tetranuclear Mixed-Spin Nickel(II) Complexes with 2,6-Bis(salicylideneaminomethyl)-4-methylphenol
Authors: Mikuriya Masahiro , Nakadera Keiichi , Kotera Takanori 
Published: June 2006

Abstract
Dinuclear and tetranuclear nickel(II) complexes with 2,6-bis(salicylideneaminomethyl)-4-methylphenol (H3L), [Ni2(L)(pz)(Hpz)(CH3OH)]·CH3OH (1) and [Ni4(L)2(pz)2(CH3OH)] (2) (Hpz = pyrazole), have been synthesized and characterized by infrared and electronic spectra, and by temperature dependence of magnetic susceptibilities (80—300 K). The molecular structures of 1 and 2 were determined by single-crystal X-ray structure analysis. Complex 1 is a mixed-spin state complex in which one metal center is square planar and the other octahedral. Complex 2 has a zigzag tetranuclear structure, in which two dinuclear units with mixed spin-states are associated by two phenoxo-bridges and one methanol bridge.
Chemoselective Reductive Coupling of Nitroarenes with Magnesium in Methanol via Single Electron Transfer
Authors: Khurana Jitender M , Ray Abhijit 
Published: June 2006

Abstract
A chemoselective reductive coupling of nitroarenes using magnesium in methanol has been reported at ambient temperature. While the cyano, formyl, methoxycarbonyl, methyl, methoxy, phenyl, amino, and chloro groups are unaffected, iodo and bromo groups undergo dehalogenation but in a slower reaction than the coupling of nitro group. The coupling is believed to be proceeding via SET from Mg to nitroarenes.
Preparation of Novel 1,6-Anhydro-β-lactose Derivatives for the Synthesis of N-Acetyllactosamine-Containing Oligosaccharides
Authors: Tsuda Tetsuro , Furuike Tetsuya , Nishimura Shin-Ichiro 
Published: June 2006

Abstract
Versatile intermediates for the syntheses of cell-surface oligosaccharides bearing N-acetyllactosamine units have been prepared from a readily available 1,6-anhydro-β-lactose as a key starting material. Regioselective chemical manipulations of 1,6-anhydro-β-lactose were carried out in a stepwise procedure and gave fully-protected lactosamine derivatives. It was clearly suggested that modification at C-3′ position of the galactose residue and the following introduction of a sterically hindered leaving group at C-2 position of the reducing glucose remarkably accelerated and facilitated further derivatization of this potential disaccharide material. Selective generation of hydroxyl groups at C-3, C-3′, and/or C-6′ positions proceeded smoothly in mild conditions and afforded a series of fully-functionalized disaccharide-acceptors in high yields.
Synthesis and Some Reactions of Molybdenocene Derivatives Coordinated with the Chiral Carboxylato Ligands
Authors: Ito Takashi , Wan Lin-Ming , Minato Makoto 
Published: June 2006

Abstract
Molybdenocene derivatives with some chiral carboxylato ligand of the types, Cp2MoH(OCOR*), Cp2Mo(OCOR*)2, Cp2MoH(OCO-E*-OCO)MoHCp2, [Cp2Mo(OCOR*)]+R*CO2−, are prepared by the reaction of Cp2MoH2 with chiral 2-methylbutanoic acid, mandelic acid, O-acetylmandelic acid, tartaric acid, and O,O′-diacetyltartaric acid in the presence of ketone and are characterized spectroscopically. Enantioselectivity in the reduction of the prochiral ketones using some of these hydridocarboxylato derivatives is examined.
Selective Formation of 2-Hydroxy-3,3-bis(hydroxymethyl)-γ-butyrolactone from Formaldehyde on Hydrotalcite-Type Catalysts
Authors: Mizutani Tadashi , Miki Yasushi , Nakashima Ruka , Fujita Haruo , Ogoshi Hisanobu 
Published: June 2006

Abstract
As a model for prebiotic sugar formation under neutral to acidic conditions, reactions of formaldehyde over hydrotalcite-type catalysts were investigated. Heating an aqueous solution of formaldehyde at 140—200 °C for 12 h over Ni–Fe hydrotalcite-type catalyst afforded 2-hydroxy-3,3-bis(hydroxymethyl)-γ-butyrolactone selectively, a 5.8% yield based on gas–liquid chromatographic analysis. The structure was identified by 1H and 13C NMR and 1H–13C HSQC, HMBC and 13C–13C 2D INADEQUATE NMR experiments.
Reductive α-Substitution of Sulfoxides with Grignard Reagents Promoted by a Magnesium Amide
Authors: Kobayashi Kazuhiro , Yokota Kouichi , Akamatsu Hideki , Morikawa Osamu , Konishi Hisatoshi 
Published: June 2006

Abstract
The reactions of sulfoxides bearing α-hydrogen(s) (RSOCHR1R2: R-alkyl or aryl; R1, R2 = H, alkyl, or aryl) with Grignard reagents (R3MgBr: R3 = Et, Ph, or vinyl) in the presence of the diisopropylaminomagnesium reagent, generated in situ by the treatment of diisopropylamine with the appropriate Grignard reagents in diethyl ether, have resulted in the formation of the corresponding sulfides (RSCR1R2R3) in moderate to good isolated yields.
Preparations of N
α-Fmoc-O-[(Benzyloxy)hydroxyphosphinyl] β-Hydroxy α-Amino Acid Derivatives
Authors: Wakamiya Tateaki , Nishida Takatoshi , Togashi Ryusaku , Saruta Kunio , Yasuoka Jun-ichi , Kusumoto Shoichi 
Published: June 2006

Abstract
N α -Fmoc-O-[(benzyloxy)hydroxyphosphinyl]serine and Nα-Fmoc-O-[(benzyloxy)hydroxyphosphinyl]threonine were prepared in order to be utilized for the synthesis of phosphoserine- or phosphothreonine-containing peptides based on the Fmoc-mode pre-phosphorylation strategy. These derivatives were obtained as crystalline compounds, which are favorable for use as building blocks for an automated peptide synthesis by a solid-phase method.
Activity Stabilization of Ga-MFI Zeolite Catalyst Modified by Chemical Vapor Deposition
Authors: Bhat Yajnavalkya Subray , Das Jagannath , Halgeri Anand Bhimrao 
Published: June 2006

Abstract
The chemical vapor deposition of silica on Ga-MFI zeolite was carried out using tetraethyl orthosilicate. The enhancement in para selectivity during toluene alkylation with the extent of silica deposition was closely monitored. The effect of reaction temperature on the behavior of silica deposited Ga-MFI zeolite was established. A deactivation trend in toluene conversion was observed when the zeolite was employed for alkylation for longer periods. The reasons for catalytic deactivation and stability enhancement by in situ coking are discussed.
A Nuclear Magnetic Relaxation Study of the Dynamics of NO3− and SCN− Ions in Liquid Ammonia
Authors: Gruwel Marco L H 
Published: June 2006

Abstract
A nuclear magnetic relaxation study of the rotational dynamics of nitrate and thiocyanate anions in 1 M solutions of liquid ammonia is presented. For both anions D⊥ was determined and shown to be larger than observed in aqueous solution. The rotational anisotropy of the nitrate ion was found to be temperature dependent (233—303 K). Thiocyanate ion 13C relaxation was found to be dominated by the spin rotation mechanism. The overall dynamics of both ions is shown to be less restricted in liquid ammonia compared to their dynamics in aqueous solutions.
Anomalous Formation of Ion Conducting Polymer-Networks in Polymer Films
Authors: Ohta Takayuki , Sano Shiho 
Published: June 2006

Abstract
An amphiphilic graft-copolymer consisting of ionic segments (quaternary ammonium groups) and aliphatic polyester segments which are compatible with various polymers was synthesized by radical copolymerization of a (methacryloxyethyl)trimethylammonium chloride and a poly(β-methyl-δ-valerolactone) macromer. Polymer blends containing this graft-copolymer showed both low surface resistance and low volume resistivity, due to the network formation of the graft-copolymer in the polymer matrix. Scanning electron microscopy revealed that the graft copolymer forms interconnected granular aggregates, which function as ion-conducting channels.
Adsorption Behavior of Sulfamethoxazole onto an Alumina-Solution Interface
Authors: Bajpai Anil Kumar , Rajpoot Manjulata 
Published: June 2006

Abstract
The adsorption measurements of sulfamethoxazole (SM) onto an alumina surface have been done at room temperature with an object to study the mode of SM adsorption at the solution–alumina interface. It is found that the adsorption isotherm is of the Langmuir type, showing a uni-layer formation of the SM molecules on the alumina surface. The adsorption is pH-dependent and found to increase with increasing pH of the medium. The adsorption is quite sensitive to the presence of Cl− and SO42− ions also and shows much interesting variation with increasing concentrations of the added anions. The adsorption also decreases with increasing temperature of the adsorption medium. Various kinetic and adsorption parameters such as the adsorption coefficient, rate constants for the adsorption and desorption, and surface coverage have been evaluated with the help of a proposed kinetics scheme.
Experimental Studies of Ozone Depletion by Chlorofluorocarbons (CFC’s), Bromofluorocarbons (BFC’s), Hydrochlorofluorocarbons (HCFC’s), and CH3Br Using a 6-m3 Photochemical Chamber
Authors: Washida Nobuaki , Imamura Takashi , Bandow Hiroshi 
Published: June 2006

Abstract
Ozone destruction by CFC’s (CFCl3 and CF2Cl2), BFC’s (CF3Br and C2F4Br2), HCFC’s (CH3CCl2F, CF3CHCl2, and CF3CHFCl), and CH3Br was demonstrated using a 6-m3 evacuable photochemical chamber equipped with UV-enhanced Xe arc lamps. The decay of ozone by a catalytic cycle involving Cl or Br atoms released from the photolysis of halocarbons by UV light was evident, although the chain length was far less than that in the real stratosphere: It was about 8 for CFCl3 and 40 for CF3Br. The rates of ozone decomposition were faster in the BFC’s than in the CFC’s. According to a box-model simulation, in the CFCl3 system 90% of the catalytic cycle proceeds from reactions of Cl + O3 → ClO + O2 and ClO + O → Cl + O2. On the other hand, in the CF3Br system 90% of the catalytic cycle is governed by the following reactions: Br + O3 → BrO + O2 and BrO + BrO → 2Br + O2. The HCFC’s and CH3Br can destroy the ozone with sufficient potential as CFC’s and BFC’s when they enter the stratosphere.
Infrared Laser-Induced Photo-Thermal Phase Transition of an Aqueous Poly(N-isopropylacrylamide) Solution in the Micrometer Dimension
Authors: Ishikawa Masazumi , Misawa Hiroaki , Kitamura Noboru , Fujisawa Ryo , Masuhara Hiroshi 
Published: June 2006

Abstract
The phase transition of an aqueous poly(N-isopropylacrylamide) solution (PNIPAM, wt% = 1.8—3.6%) was induced by the irradiation of a focused (ca. 1 μm) 1064-nm laser beam; this brought about the formation of a single PNIPAM microparticle. The diameter of the particle was controlled to 2—9 μm through the laser power, polymer concentration, and solution temperature. The primary origin of particle formation was the photo-thermal phase transition of the polymer solution through the local heating of water (H2O) by the laser beam. The characteristic features of the phenomena, including manipulation of the PNIPAM particle by the incident laser beam and the role of radiation force for the particle formation, are discussed.