bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Facile and Practical Synthesis of 1-Aryl-3,3,3-trifluoropropynes
Authors: Hiyama Tamejiro , Sato Ken-ichi , Fujita Makoto 
Published: July 2006

Abstract
A facile and practical method for the synthesis of ArC≡CCF3 is described which involves (1) conversion of aldehydes ArCHO into ArCH=CClCF3 with 1,1,1-trichloro-2,2,2-trifluoroethane, zinc powder, and acetic anhydride in one-pot and (2) dehydrochlorination with sodium t-butoxide or sodium amide/t-butyl alcohol.
Sodium Telluride-Mediated Sulfenylation of α-Halo Carbonyl Compounds with Diphenyl Disulfide
Authors: Padmanabhan Seetharamaiyer , Ogawa Takuji , Suzuki Hitomi 
Published: July 2006

Abstract
Under mild aprotic conditions α-halo carbonyl compounds react with diphenyl disulfide in the presence of sodium telluride to give the corresponding α-phenylthio derivatives in good to moderate yields. The reaction appears to proceed involving the sulfur–sulfur bond cleavage of diphenyl disulfide by sodium telluride.
Stereospecific Preparation of Chiral 1,5-Diketone by One-Methylene Incorporated Dimerization Reaction of d-Camphor Enolate and Reduction of the 1,5-Diketone
Authors: Kiyooka Syun-ichi , Yamashita Tsuneo , Yamamoto Akihisa , Fujiyama Ryoji 
Published: July 2006

Abstract
The reaction of d-camphor with N,N-dimethylformamide (DMF) in the presence of potassium hydride stereoselectively gave bis[(1R,3S,4R)-2-oxo-3-bornyl]methane (1). This new condensation reaction is proposed to proceed by an attack of the d-camphor enolate to DMF and a subsequent reduction. Three chiral diols were obtained from the reduction of 1.
A 13C NMR Relaxation Study of Octyltrimethylammonium Salts in D2O
Authors: Uzu Yuhei , Saito Yasushi , Yokoi Masatoki 
Published: July 2006

Abstract
The concentration dependence of the 13C spin-lattice relaxation times (T1) of the alkyl carbons in octyltrimethylammonium salts was analyzed by means of applying the phase separation model. At higher concentration, the 1/T1 value deviates from a linear plot and depends on the magnetic field strength. The molecular motions in monomer and micellar states are discussed, along with the overall motions of the molecule and its internal motion.
Molecular Complexes of Cyclophanes. XV. Charge-Transfer Complexes of Sterically Hindered[2.2]metapara- and [2.2]paracyclophanes with π-Acceptors
Authors: Mourad Aboul-fetouh E , Hassan Alaa El-Din A , Dannheim Jörg 
Published: July 2006

Abstract
The charge-transfer (CT) complexes of some sterically hindered [2.2]metapara- and [2.2]paracyclophanes as π-donors with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tetracyanoethylene (TCNE) as π-acceptors have been investigated by electronic as well as infrared spectroscopy. Electronic, steric, and transannular effects governing the formation and stability of the CT complexes studied are discussed.
Detection of Photoinduced Intramolecular Electron Transfer in 4-(1-Pyrenyl)butyl 9-Anthracenecarboxylate by Transient Absorption and Resonance CARS Spectra
Authors: Kamisuki Toshio , Akamatsu Naotoshi , Adachi Yukio , Hirose Chiaki , Yamamoto Noritaka , Takuma Keiichi , Iwamura Michiko 
Published: July 2006

Abstract
Transient absorption and resonance CARS spectra of title molecule have been observed in acetonitrile solution to show the presence of cationic pyrenyl group and anionic 9-anthryl group (or 9-anthracenecarbonyloxy group). The 337 nm UV pulse was used for the excitation. The result was combined with the linear dependence of the signals on the intensity of UV pulse to prove that the ionic radicals were produced by the intramolecular electron transfer from the locally excited pyrenyl group to the 9-anthryl group (or 9-anthracenecarbonyloxy group).
Electrical and Magnetic Properties of (BEDT-TTF)4Ni(CN)4 Complex
Authors: Tanaka Masashi , Takeuchi Hideo , Sano Mitsuru , Enoki Toshiaki , Suzuki Kazuya , Imaeda Kenichi 
Published: July 2006

Abstract
The electrical conductivity and the ESR spectra of the single crystal of (BEDT-TTF)4Ni(CN)4 complex were measured. This crystal exhibits a metal–insulator transition at 160 K. The ESR signals show the presence of the [NiIII(CN)4]− anion in addition to the BEDT-TTF cation radical. The spin concentration of Ni(III) ion was estimated to be 0.01 of the total Ni ions from the temperature dependence of the spin susceptibility of these components. The X-ray photoelectron spectra were also taken.
Aromatic Hydroxylation with an Iron(III)–Catechol–H2O2 System. Mechanistic Implication of the Role of Catechol
Authors: Tamagaki Seizo , Suzuki Kenji , Tagaki Waichiro 
Published: July 2006

Abstract
The role of catechol in benzene hydroxylation with Fe3+/catechol/H2O2 system, the so-called Hamilton system, has been mechanistically investigated by using tiron as a substitute for pyrocatechol. The yield of phenol progresses linearly with reaction time. The phenol yield is dependent on the mole ratio of Fe3+ relative to tiron, and the ratio of more than unity is particularly important for the effective functioning of the catalyst system. The o-, m-, and p-product isomer distributions for a few aromatic hydrocarbons are nearly identical with those of the Fenton reaction. These and the separate experimental results are consistent with the mechanism involving the rate-limiting redox reaction between tiron and Fe3+ and then the follow-up radical chain sequence as in the Fenton reaction.
Dispersion Behavior of Solutes in an Ideal Laminar Flow with Small-Bore Glass Tubes
Authors: Korenaga Takashi , Shen Fenghua , Yoshida Hirofumi , Takahashi Teruo 
Published: July 2006

Abstract
The dispersion behavior of solute molecules injected as a sample plug into an ideal laminar capillary flow was experimentally analyzed by means of microscopic and microphotometric methods. The flow pattern in small-bore glass tubes was directly observed by the microscopic method using a camera. The peak responses obtained for the colored solutes by means of the microphotometric method consist of double-humped peak features which resulted from both laminar flow convection and the molecular diffusion of solute molecules at the parabolic interface between the sample plug and the carrier fluid. The influences of the diffusion coefficient of the solute, the flow rate, the tube length, the tube diameter, etc. were mainly investigated in order to guide the design and optimization of the flow systems of capillary liquid chromatography (CLC), capillary electrophoresis (CEP), flow-injection analysis (FIA), etc. The experimental results obtained here are in good agreement with the theoretical results obtained by the numerical solution for the diffusion-convection equation.
The Determination of a Small Amount of a Biological Constituent by the Use of Chemiluminescence. XV. A Zeolite Column-Chemiluminescence Detection System for the Separation and the Determination of a Protein Mixture
Authors: Hara Tadashi , Tsukagoshi Kazuhiko , Kurita Yuichiro 
Published: July 2006

Abstract
To make use of zeolite as the packing material for the separation of proteins by means of adsorption chromatography, the adsorption behavior of protein onto the Na-X type of zeolite (Molecular Sieve 13X) in an aqueous solution or onto a column (3 mm i.d.×50 mm) packed with the same zeolite as above was examined using a ultraviolet absorption detector and model proteins, such as human-serum albumin and human-serum γ-globulin. The following results were obtained: 1) Human-serum γ-globulin was much more adsorbed onto the zeolite than was human-serum albumin and 2) in general, more protein was adsorbed in an acidic solution than in an alkaline solution. Moreover, a chemiluminescence detector using a 1,10-phenanthroline–hydrogen peroxide–copper(II) system, which has been developed by the present authors, was modified to improve its sensitivity for the determination of protein. Both the carrier solution and the eluting solution which were used in combination with a zeolite column with a chemiluminescence detector were optimized so as to give a smooth baseline on a recorder. A microbore zeolite column (1 mm i.d.×250 mm)-chemiluminescence detection system suitable for the separation and the determination of a small amount of a protein mixture was established on the basis of these experimental results. Since human-serum albumin passed through a microbore zeolite column, while human-serum γ-globulin was retained on the column, when a model sample containing human-serum albumin and human-serum γ-globulin was injected into the column, human-serum albumin was first determined, followed by the determination of human-serum γ-globulin after its desorption. Both human-serum albumin and human-serum γ-globulin in the concentration range of 2×10−5–5×10−3 g dm−3 could be determined economically and conveniently, with a detection limit of about 1 ng (injected sample volume: 50 mm3; S/N=2). The present method was, therefore, applicable to the separation and the determination of albumin and globulin in a serum sample.
Dynamic NMR as a Nondestructive Method for the Determination of Rates of Dissociation. XVI. Mechanism of Sulfur Inversion in Platinum(II)–Thioether Complexes Revisited
Authors: Toyota Shinji , Yamada Yasuhisa , Kaneyoshi Masami , Oki Michinori 
Published: July 2006

Abstract
The mechanism of sulfur inversion in some platinum(II)–thioether complexes was reinvestigated with the use of the dynamic NMR technique. Activation parameters for the sulfur inversion in [(isopropylthio)acetato-O,S]bis(triphenylphosphine)platinum(II) perchlorate in CDCl3 were obtained by taking advantage of the line shape changes in its 1H NMR spectra at various temperatures as follows: ΔH\eweq 18.0±0.4 kcal mol−1, ΔS\eweq 4.0±1.4 cal mol−1 K−1. The kinetic parameters varied little, though the rates of inversion were determined in other solvents. The entropy of activation and the solvent effects together with the presence of coupling between the phosphine-31P and the methine-1H throughout the temperature range of investigation evidence the sulfur inversion without breaking the Pt–S bond. The sulfur inversion in dichlorobis(dialkyl sulfide)platinum(II) in nonpolar solvents was also concluded to take place without bond breakage.
EXAFS and XANES Spectra of Cobalt(III) EDTA Complexes in Solids and Solutions
Authors: Sakane Hideto , Watanabe Iwao , Ikeda Shigero 
Published: July 2006

Abstract
The Co K-edge XANES (X-ray Absorption Near-Edge Structure) of [Co(edta)]− (edta4−=ethylenediamine-N,N,N′,N′-tetraacetate) complex in crystal varies with the kind of counter cations and it also varies with the kind of solvents when it is dissolved. The amplitude of the oscillation in its EXAFS (Extended X-ray Absorption Fine Structure), or the peak height in its Fourier transform, also varies as much as threefold depending on the kind of counter cations or solvents. The most plausible cause for the variations is the difference in the thermal disorder of the bonds which is enhanced by the formation of hydrogen bonding between carboxylato groups in the complex and the water molecules in crystal or the solvent molecules in solution.
Preparation and Characterization of Cobalt(III) Complexes Containing (2-Aminoethyl)dimethylarsine (edma). Resolution and Racemization of fac-[Co(edma)3]3+
Authors: Nemoto Kazuhiro , Kita Masakazu , Kojima Masaaki , Fujita Junnosuke 
Published: July 2006

Abstract
(2-Aminoethyl)dimethylarsine (edma) and its cobalt(III) complexes, trans(X,X),cis(As,As)-[CoX2(edma)2]+ (X=Cl, Br, and I), trans(As,As)- and trans(As,N)-[Co(acac)(edma)2]2+ (acac=acetylacetonate ion), trans(As,N)-[Co(CO3)(edma)2]+, [Co(acac)2(edma)]+, and fac-[Co(edma)3]3+ were prepared and characterized. From a comparison of the first d–d absorption bands of analogous diamine and (2-aminoethyl)dimethylphosphine (edmp) complexes, the spectrochemical series of Group 5B elements was found to be P&gt;As&gt;N. The fac-[Co(edma)3]3+ complex was resolved and the absolute configuration of the (+)490CD-isomer was assigned to Λ on the basis of the CD spectrum. Racemization of fac-[Co(edma)3]3+ was studied in aqueous solutions in the pH and temperature ranges of 7.88–9.32 and 35.0–50.0 °C, respectively. The racemization obeyed a rate law of the form, R=k[OH−][complex]. The activation enthalpy and entropy values were found to be ΔH\eweq=132±4 kJ mol−1 and ΔS\eweq=171±11 J K−1 mol−1, respectively.
A New Method for the Preparation of α-Methylene-γ-butyrolactones Using 3-Ethoxycarbonyl-3-(phenylsulfonyl)cyclobutanone
Authors: Fujiwara Tooru , Morita Koichi , Takeda Takeshi 
Published: July 2006

Abstract
The reaction of 3-ethoxycarbonyl-3-(phenylsulfonyl)cyclobutanone with Grignard reagent or aryllithium gave 1-(alkyl or aryl)-3-ethoxycarbonyl-3-(phenylsulfonyl)cyclobutanol which was treated with potassium hydride, reduced with LiBH4 in the presence of ZnCl2, and treated with p-TsOH or aluminum triisopropoxide successively to give α-methylene-γ-butyrolactone in good yield.
Topochemical Photopolymerization and Photo-Copolymerization of the Crystals of Unsymmetrically Substituted Diolefin Compounds Having Pyrimidine Ring
Authors: Hasegawa Masaki , Endo Yasuhiro , Aoyama Masato , Saigo Kazuhiko 
Published: July 2006

Abstract
Several new diolefin compounds, methyl and ethyl 4-[2-(4-pyrimidyl)ethenyl]cinnamates (1a and 1b), and methyl, ethyl, and propyl α-cyano-4-[2-(4-pyrimidyl)ethenyl]cinnamates (1c, 1d, and 1e) were synthesized, and their photoreactivity in the crystalline state was investigated. The crystals of 1c, 1d, and 1e gave amorphous oligomers having cyclobutane skeletons (average degree of polymerization was approximately 10) through the [2+2] photocycloaddition. The dimers (2c, 2d, and 2e) were formed in high yields by the exclusive photoexcitation of the monomers. The dimers were isolated by column chromatography. The cyclobutane structure of 2c and 2d was β-type homo adduct whereas that of 2e was β-type hetero adduct. As only one type of adduct was detected for each crystal, photodimerization was interpreted as being of a crystal lattice controlled process. The conversions of these reactions were not as high as that of the reaction in α-type of 2,5-distyrylpyrazine (DSP). The lower conversion was interpreted as being due to alternative reacting sites which inevitably result from the β-type molecular packing and to the drastic displacement of molecules which causes the distortion of crystal lattice. The mixed crystals (1f) of 1d and 1e (molar ratio 1.3/1), of which the X-ray diffraction pattern is similar to that of 1e, photopolymerized to give amorphous cooligomers (average degree of polymerization was approximately 5). The reaction went through an intermediate similar to dimer 2e.
Synthetic Photochemistry. XLIX. Synthesis and Photoisomerization of 2-Acetyl-2-azatricyclo[6.2.2.01,5]dodeca-4,6,9,11-tetraen-3-one. An MO Explanation of the Cycloaddition of Cyclohepta[b]pyrrol-2(1H)-ones
Authors: Tian Guan Rong , Mori Akira , Takeshita Hitoshi , Higashi Miwako , Yamaguchi Hiroyuki 
Published: July 2006

Abstract
Thermal cycloaddition reactions of 2,3-bis(methoxycarbonyl)-7-oxabicycloheptadiene with cyclohepta[b]pyrrol-2(1H)-ones gave the [4+2]adducts and products derived from the [8+2]adducts. Among [4+2]adducts, a new adduct was isolated. Cyclohepta[b]pyrrol-2(1H)-ones, having a substituent at the C-3 position exclusively, gave [4+2]adducts. The photolysis of 2-azatricyclo[6.2.2.01,5]dodeca-4,6,9,11-tetraen-3-one afforded substituted 9-methylenebarbaralane, 5-methylenetricyclo[4.3.0.02,9]nonadiene, and 1-methylenedihydroindene derivatives.
Phosphonylation of Biomolecules with Inorganic Diphosphonate. III. Formation of an H-phosphonate Analogue of Adenosine 5′-Triphosphate by Phosphonylation of Adenosine 5′-Diphosphate
Authors: Baba Yoshinobu , Sumiyama Tomoko , Tsuhako Mitsutomo , Yoza Norimasa 
Published: July 2006

Abstract
Phosphonylation of adenosine 5′-diphosphate (ADP) with inorganic diphosphonate was investigated by use of 31P NMR spectroscopy and the coupled system of high-performance liquid chromatography and flow injection analysis. ADP was phosphonylated by inorganic diphosphonate to form an H-phosphonate analogue of adenosine 5′-triphosphate (ATP) in aqueous solutions. The yield of the H-phosphonate analogue of ATP varied strongly depending on reaction conditions: pH and initial concentration of inorganic diphosphonate. The maximum yield of the H-phosphonate analogue of ATP was 56% under the following conditions: initial concentration of inorganic diphosphonate and ADP were 1.8 and 0.1 mol dm−3, respectively; 50 °C; pH 5; 90 min. In basic solutions, 2′ or 3′-hydroxyl group on ADP was predominantly phosphonylated.
The Catalytic Role of a Flavin Analogue for Aromatic Hydroxylation with the Udenfriend System
Authors: Tamagaki Seizo , Sasaki Masaaki , Tagaki Waichiro 
Published: July 2006

Abstract
A new combination of the Udenfriend reagent and a flavin analogue was found to hydroxylate benzene to phenol. Effects of temperature and concentrations of reaction components, i.e., iron(II), flavin, and ascorbate, on the phenol yield were examined. In particular, decreasing ascorbate concentration increased the yield of phenol. Thus, 68% of the yield was obtained under better conditions. The mechanism of action of ascorbic acid and the flavin was discussed.
A Spectroscopic Characterization of Metal Ion-Complexed NADH Models and Their Kinetic Behavior in Nitrosobenzene Reduction
Authors: Tamagaki Seizo , Simojo Yoshitaka , Mimura Takasi , Tagaki Waichiro 
Published: July 2006

Abstract
The structures of metal ion complexes of a series of NADH models were spectrophotometrically investigated. The electronic spectra were sensitive to variation of both the 1,4-dihydropyridines and the metals; particularly, 1-benzyl-3,5-bis(1-pyrrolidylcarbonyl)-1,4-dihydropyridine (BPDH) was recognized to produce two types of complexes with zinc and lead perchlorates, whereas 1-benzyl-1,4-dihydronicotinamides (BNAH) complexed metal ion only at the amide oxygen. In order to elucidate these structures, the effect of changing perchlorate ion concentrations was examined. In addition, reduction of nitrosobenzene in the presence of bivalent metal cations was kinetically investigated.
Synthesis of 2-Alkyl-Substituted 1,3-Diketones via the 1,4-Addition of the Grignard Reagents to α,β-Unsaturated Imidates
Authors: Inoue Seiichi , Suzuki Osamu , Sato Kikumasa 
Published: July 2006

Abstract
4-Propyl-3,5-nonanedione was selectively formed by the reaction of methyl N-phenylacrylimidate with ethylmagnesium bromide in 80% yield. Similar diketones were obtained from methyl N-phenylcrotonimidate and N-phenylcinnamimidate with the Grignard reagents. The coupling of N-magnesio α-methoxy enamine and ketenimine, both of which are formed through the initial 1,4-addition of the Grignard reagent to α,β-unsaturated imidate, is the most plausible pathway for the formation of the diketones.
Synthesis of a Functionalized Carbocyclic Skeleton of Ptaquilosin, the Aglycone of a Bracken Carcinogen Ptaquiloside Based on an Intramolecular Diels–Alder Reaction
Authors: Kigoshi Hideo , Sawada Akihiko , Niwa Haruki , Yamada Kiyoyuki 
Published: July 2006

Abstract
A tricyclic compound 13 possessing the carbocyclic skeleton of ptaquilosin (2), the aglycone of a bracken carcinogen ptaquiloside (1) has been synthesized by the intramolecular Diels–Alder reaction of trienes 12a and 12b.
Oxidation of Methoxy- and/or Methyl-Substituted Benzenes and Naphthalenes to Quinones and Phenols by H2O2 in HCOOH
Authors: Orita Hideo , Shimizu Masao , Hayakawa Takashi , Takehira Katsuomi 
Published: July 2006

Abstract
The oxidation of a number of arenes (methoxybenzenes, methylbenzenes, and naphthalenes) to quinones and phenols by H2O2 in HCOOH has been examined. Methoxybenzenes were much more easily oxidized to p-benzoquinones than methylbenzenes (e.g., 1,3,5-trimethoxybenzene was oxidized to 2,6-dimethoxy-p-benzoquinone in a 75% yield and 1,2,4-trimethylbenzene to 2,3,5-trimethyl-p-benzoquinone in a 16% yield). Electronwithdrawing substituents, such as nitro, cyano, and chloro groups, lowered the conversion of reactants and changed the product selectivity from quinones to phenols. Methoxybenzonitriles were oxidized to corresponding phenols in a moderate yield (e.g., 2,6-dimethoxybenzonitrile to 3-hydroxy-2,6-dimethoxybenzonitrile in a 39% yield and a 64% selectivity).
Synthetic Photochemistry. L. Isolation and the X-Ray Structure Determination of Photocyclodimers Formed by UV-Light Irradiation of Alkyl 2,4-Dioxopentanoates
Authors: Mori Akira , Nishiyama Nobuaki , Kohguchi Yukiko , Shinka Hisayo , Takeshita Hitoshi 
Published: July 2006

Abstract
Upon UV-light irradiation with a high-pressure mercury lamp, methyl 2,4-dioxopentanoate in a mixture of benzene and cyclohexane afforded a crystalline head-to-head[2+2]cyclodimer. Its structure was elucidated by a single-crystal X-ray analysis, as well as 1H and 13C NMR spectroscopy. Ethyl 2,4-dioxopentanoate also gave a cyclodimer.
A Convenient Synthesis of Diketones via Alkylation of Alkyl Methyl Ketone Dimethylhydrazones
Authors: Yamashita Masakazu , Matsumiya Kaoru , Morimoto Hiroko , Suemitsu Rikisaku 
Published: July 2006

Abstract
Symmetrical diketones were prepared by the reaction of the lithium salts of alkyl methyl ketone dimethylhydrazones with dibromoalkanes.
Reactions of Metal Benzoylacetonates and Acetylacetonates with Formaldehyde
Authors: Takeichi Tsutomu , Okumura Hiroaki , Sakurada Yoshihiro , Takayama Yuzi 
Published: July 2006

Abstract
The reaction of cobalt benzoylacetonate with formaldehyde in water or methanol gave benzoic acid along with 4-hydroxy-3,3-bis(hydroxymethyl)-2-butanone or 4-methoxy-3,3-bis(hydroxymethyl)-2-butanone, respectively. The result suggests the formation of acetic acid in the reaction of metal acetylacetonate.
Basicity of Water in Hydrogen-Bonded Networks of Methanol–1,2-Dichloroethane Mixtures Using the [(1R,4S,8R,11S)-1,4,8,11-Tetramethyl-1,4,8,11-tetraazacyclotetradecane]nickel(II) Cation as a Probe of Electron-Pair Acceptance
Authors: Iwamoto Etsuro , Yamasaki Shoji , Kumamaru Takahiro 
Published: July 2006

Abstract
The basicity of water in methanol (MeOH) and MeOH–1,2-dichloroethane (DCE) mixtures was examined by using spectral data of the title square planar chelate cation ([Ni(tmc)]2+). Although MeOH molecules are hardly coordinated to the chelate, the water molecules hydrogen-bonded with MeOH are easily coordinated to the cation, depending on the degree of hydrogen-bonded networks of MeOH. A fitting method showed that in the MeOH-rich mixtures the dimerization of water occured and only the terminal monomeric water molecule in the MeOH oligomer could be coordinated. The equilibrium constant KNiW1=[Ni(tmc)(H2O)2+]/[Ni(tmc)2+][H2O] was 3.2 in the 0.1 MeOH mole fraction mixture, 3.0 in 0.3, 3.2 in 0.5, 6.2 in 0.7, 9.5 in 0.9, 10.0 in 1.0. Linear relationships of 1H chemical shift of the OH group for MeOH in various solvents with the KNiW1 values and Gutmann’s donor number (DN) were found and DN values were estimated for the DCE–MeOH mixtures. The enhancement of basicity of the water molecules was discussed from the viewpoints of the charge transfer effect through hydrogen bonding and the development of hydrogen-bonded networks.