bluuebunny/crossref_metadata_2025_split huggingface dataset:
Convenient Preparation of Dimethyl (Trifluoromethyl)malonate and Related Compounds
Authors: Ishikawa Nobuo , Yokozawa Tsutomu 
Published: July 2006

Abstract
The preparative method for dimethyl (trifluoromethyl)malonate (4) from the adduct of perfluoro-2-methylpropene with methanol was improved, and several reactions of this base-sensitive substance were investigated. Alkylation of 4 was achieved by using CsF as a condensing agent, and the Michael addition on vinyl ketones proceeded in triethylamine–pyridine medium.
Lanthanoid Nitrate Complexes with Some Polyethylene Glycols and Glymes
Authors: Hirashima Yoshiyuki , Kanetsuki Koji , Yonezu Ikuo , Kamakura Kiyohito , Shiokawa Jiro 
Published: July 2006

Abstract
Lanthanoid nitrates (Ln(NO3)3) formed solid complexes with several polyethylene glycols and glymes. The compositions of the complexes were 1:1 (Ln:ligand) for triethylene glycol(EO3), tetraethylene glycol(EO4), pentaethylene glycol(EO5), and tetraglyme, 1:2 (Ln:ligand) for diethylene glycol, 2:1 for heptaethylene glycol, and 4:3 for pentaglyme and hexaglyme. Solid complexes were deposited also for hexaethylene glycol, but their compositions were not definitely determined. The solid complexes obtained here were all deliquescent. The deposition of the complexes was generally interfered with by water in the solution, and was not observed for some heavier lanthanoids when a small amount of water was present in the solution. The solubilities of the solid complexes with EO4 and EO5 increased with an increase in the atomic number of the lanthanoid, a fact suggesting a unique selectivity of the glycols. The infrared absorption bands of polyethylene glycols or glymes in the 1000–1150 cm−1 region became sharper upon the complexing of the glycols or glymes with lanthanoids; this sharpening can be explained by the change in the conformations in the ligand molecules.
The Adsorption of Tetramethylurea at the Mercury/Water Interface
Authors: Ikeda Osamu , Jimbo Hiroyuki , Tamura Hideo 
Published: July 2006

Abstract
The adsorption of tetramethylurea (TMU) at the mercury/water interface was studied by means of differential capacity measurements. TMU was found to take three different orientations, depending on the surface excess and the charge sign of the electrode. These orientations could not be explained simply by the orientation of the TMU dipole in the electric field or by the hydrophobic interaction between the methyl groups of TMU and the electrode, but it was explained on the basis of interactions between TMU and water molecules, and on the basis of the TMU molecules themselves in the adsorption layer and an electronic polarization effect of the nitrogen atoms in TMU. A few water-adsorption models were compared in an attempt to estimate the dipole moment of the TMU molecule at the interface.
Synthesis and Characterization of a New Family of Binuclear Nickel(II) Complexes with a Terephthaloyl or Isophthaloyl Bridge
Authors: Matsumoto Naohide , Hirano Akira , Ohyoshi Akira 
Published: July 2006

Abstract
A new family of binuclear nickel(II) complexes with a terephthaloyl or isophthaloyl bridge have been prepared by the electrophilic substitution reaction of (11,13-dimethyl-1,4,7,10-tetraaza-10,12-cyclotridecadienato)nickel(II) (Ni(Me2[13]dienatoN4)]+) or (12,14-dimethyl-1,4,8,11-tetraaza-11,13-cyclotetradecadienato)nickel(II) ([Ni(Me2[14]dienatoN4)]+) containing a nucleophilic center at the γ-carbon and terephthaloyl chloride or isophthaloyl chloride. The complexes were characterized by elemental analyses, infrared spectra, 1H NMR spectra, electronic spectra, and conductivity measurements.
Dependence of Electric Polarizability of Rodlike DNA in Aqueous Solutions on Ionic Strength as Studied by Electric Dichroism and Birefringence. A Comparison between Experimental and Theoretical Results
Authors: Yamaoka Kiwamu , Matsuda Koichiro , Takarada Kaoru 
Published: July 2006

Abstract
Orientation of a sonicated DNA fragment in aqueous solutions containing sodium chloride (0.2–4 mmol/dm3) by an external electric field was discussed in terms of counterion-induced electric moments by using the electric dichroism and birefringence data experimentally determined at limiting low field strengths.
Thermodynamic Study on Solvent Extraction of Sodium and Potassium Picrates by Benzo-15-crown-5
Authors: Takeda Yasuyuki 
Published: July 2006

Abstract
In order to obtain enthalpy and entropy changes for extraction of sodium and potassium picrates by benzo-15-crown-5 (B15C5) between benzene and water, the overall extraction equilibrium constants for the 1:1:1 complexes of B15C5 with the salts were determined at various temperatures. The enthalpy and entropy changes for both the systems are all large and negative.
Photoinduced Alcoholysis of Trihaloacetyl Group
Authors: Izawa Yasuji , Ishiguro Katsuhiro , Tomioka Hideo 
Published: July 2006

Abstract
Photolysis of trichloroacetamide in nondegassed methanol gave methyl oxanilate (13–44%), along with carbamate (3–20%) and amine (4–12%). Similar irradiation of other trichloroacetyl derivatives of aliphatic ketone, aldehyde, and acetate afforded only radical product. The results are interpreted in terms of the mechanism involving electron transfer of the radical pair.
Benzocyclobutenes Part 8. Geometrical Isomerism of Arylhydrazones of Benzocyclobutene-1,2-dione
Authors: Cracknell Mark Edward , Goodland Michael Charles , McOmie John Frederick William 
Published: July 2006

Abstract
Four mono(arylhydrazone)s of benzocyclobutene-1,2-dione (BBD) have been prepared in which the aryl group is 2,4-dinitrophenyl, 4-bromophenyl, phenyl, and 4-nitrophenyl. The first three have been separated into their E- and Z-isomers whose configurations are assigned on the basis of spectra and Rf values. Improvements in the preparation of BBD from 1,2-dibromo-1,2-dihydrobenzocyclobutene are described.
Reaction of α,α-Bis(trimethylsilyl)phenylthiomethyllithium with (Chloromethyl)oxiranes. Synthesis of 1-Alkyl-3-phenylthio-3-trimethylsilyl-1-trimethylsiloxycyclobutanes
Authors: Takeda Takeshi , Naito Satoru , Ando Kazuo , Fujiwara Tooru 
Published: July 2006

Abstract
The cyclobutanes of the title are produced in good yields by means of the reaction of the title.
Electrochemical Properties of Electrochemically Polymerized Polypyrrole Film in the Dark and under Light Irradiation
Authors: Inoue Tooru , Yamase Toshihiro 
Published: July 2006

Abstract
Polypyrrole films prepared on Pt or SnO2 through electrochemical oxidative polymerization of pyrrole were characterized with respect to electroconductivity by photoelectrochemical measurements. Redox reactions of solution species such as methyl viologen, hydroquinone, oxygen, Cu2+, I−, and Br− occur on these electroconductive films. Light excitation of the film with wavelengths shorter than 550 nm results in observable cathodic photocurrent at the potential region more negative than 0.0 V vs. Ag. The polypyrrole film is a p-type semiconductor with a bandgap energy of ca. 2.2 eV and is stable during redox reactions.
Studies of Bitter Peptides from Casein Hydrolyzate. VII. Bitterness of the retro-BPIa (Val–Ile–Phe–Pro–Pro–Gly–Arg) and Its Fragments
Authors: Shigenaga Toshiaki , Otagiri Ken , Kanehisa Hidenori , Okai Hideo 
Published: July 2006

Abstract
To explain the bitter taste exhibited by BPIa (Arg–Gly–Pro–Pro–Phe–Ile–Val) which was isolated from casein hydrolyzate, we have proposed the following requirement: its characteristic spatial structure: the basic moiety in the N-terminal and the hydrophobic moiety in the C-terminal were affected to each other by prolylprolyl residue, is necessary for the bitterness to be exhibited. As for BPIc (Val–Tyr–Pro–Phe–Pro–Pro–Gly–Ile–Asn-His), which is the other fraction, although it exhibited as strong and bitter a taste as BPIa, the basic moiety of BPIc is located in the C-terminal and its hydrophobic moiety is located in the N-terminal. The authors synthesized retro-BPIa with the reverse peptide sequence and its fragments. The retro-BPIa exhibited as strong and bitter a taste as BPIa. However, the bitterness of the fragments of retro-BPIa was far weaker than that of retro-BPIa.
A DNMR Study of Restricted Methylene Rotation in 2-Pyridylmethyl- and 3-Methyl-2-pyridylmethyllithium
Authors: Matsui Hideki , Yoshino Akihiro , Yoshida Tadayoshi , Takahashi Kensuke 
Published: July 2006

Abstract
Thermodynamical parameters for the restricted rotation of the title carbanions have been obtained by means of the DNMR techniques. The activation energies and entropies thus obtained are about 93 kJ mol−1 and 95 J K−1 mol−1 for the two carbanions studied; these values are larger than those of the similar rotations observed in arylmethanide ions. The methylene rotation is thus extremely hindered in these carbanions.
Palladium(II)-Catalyzed Acetoxylation and Chlorination of 2-Alkenyl p-Tolyl Sulfones
Authors: Ogura Katsuyuki , Shibuya Nobuhiro , Takahashi Kazumasa , Iida Hirotada 
Published: July 2006

Abstract
2-Alkenyl p-tolyl sulfones were converted into the corresponding 3-acetoxy(or chloro)-1-alkenyl p-tolyl sulfones via π-allylpalladium complexes which reacted regiospecifically with a nucleophile such as acetate anion or chloride anion in the presence of Cu(II).
Bis(trimethylsilyl) Sulfate Catalysis in γ-Lactonization of Cyclopropanecarboxylates Activated by Carbonyl Substituents on α-Carbon
Authors: Morizawa Yoshitomi , Hiyama Tamejiro , Oshima Koichiro , Nozaki Hitosi 
Published: July 2006

Abstract
The title reaction of 1-carbonyl substituted cyclopropanecarboxylates proceeds under C(1)–C(2) bond cleavage to produce γ-lactones. Stereochemically, the reaction takes two pathways: (1) substrates with a cationstabilizing group like vinyl on C(2) give thermodynamically favored γ-lactones having the thermodynamically more stable arrangement of substituents irrespective of the configuration of the cyclopropane substrates, (2) substrates without such a cation-stabilizing group afford γ-lactones under ca. 70% inversion at C(2) reaction center.
Cycloaddition Reactions of Heteroaromatic Thioketones with Maleic Anhydride, Norbornene, Acrylonitrile, Styrene, and 2-Chloroacrylonitrile
Authors: Ohmura Haruo , Motoki Shinichi 
Published: July 2006

Abstract
Heteroaromatic thioketones react with maleic anhydride, norbornene, acrylonitrile, and styrene to form the Diels-Alder adducts, respectively. The thioketones also undergo cycloaddition with 2-chloroacrylonitrile followed by elimination of hydrogen chloride to give heteroaromatic analogues of o-quinodimethan derivatives. In these reactions, the thioketones act as a heterodiene on the dienophiles to give [4+2]cycloadducts regioselectively.
Freezing of Water as Aggregated with Cationic Surfactants in Deuterochloroform
Authors: Sunamoto Junzo , Hamada Tomiko , Kondo Hiroki 
Published: July 2006

Abstract
Freezing of water solubilized with the cationic CTAX(hexadecyltrimethylammonium halides) and QDX (dihexadecyldimethylammonium halides) in deuterochloroform was observed by 1H-NMR method. The freezing of water was largely affected by the characteristics of the water-surfactant aggregates by the R-value(=[H2O]/[surfactant]) and the structure of surfactant. In the 0.20 M (1 M=1 mol dm−3) CTABr/0.16 M H2O/CDCl3 system, for example, the apparent freezing was observed at about −20 °C.
Thermal Decomposition of t-Butyl Heptafluoroperoxybutyrate
Authors: Sawada Hideo , Hagii Hidehiko , Aoshima Kazuyoshi , Arai Takeshi 
Published: July 2006

Abstract
The decomposition of t-butyl heptafluoroperoxybutyrate (TBH) was studied in both toluene and methanol. Kinetic and product studies from the thermolysis showed that this peroxy ester decomposes heterolytically in nonpolar solvents like toluene with homolysis, whereas in methanol this peroxy ester undergoes principally transesterification.
Reaction Efficiency of Exciplexes in Singlet Sensitized Decomposition of Dibenzoyl Peroxide
Authors: Misawa Hiroaki , Kitamura Akihide , Sakuragi Hirochika , Tokumaru Katsumi 
Published: July 2006

Abstract
Quantum yields were measured for aromatic hydrocarbon-sensitized decomposition of dibenzoyl peroxide in benzene. For the sensitizers employed, naphthalene, phenanthrene, triphenylene, and chrysene, the ratio of the rate constants for decay and radical formation from intermediate exciplexes was found to be similar (0.2–0.4), indicating that the reactivity of the peroxide moiety in the intermediate is independent of the structural factors of the sensitizers as far as examined.
On the Penetration Rate and the Role of Acids in the Control of Impregnation Profiles
Authors: Komiyama Masaharu , Merrill Robert P 
Published: July 2006

Abstract
Two factors which play important roles in determining the concentration profiles in the impregnation of porous catalysts, viz., penetration rate of impregnating solution and the use of acids, were examined. The flow rate of impregnating solution into a spherical dry pellet consisting of polydispersed pores obeyed the equation which assumed constant pressure differential at the liquid front independent of its position in the pellet. The adsorption behavior of nickel ions onto γ-alumina strongly depended on the pH of the solution, and very weakly on the kind of acids used. By controlling the pH of the impregnating solution, it was possible to obtain a surface impregnation, a uniform impregnation and a subsurface impregnation for nickel on γ-alumina.
Infrared Spectroscopic Studies on the Resilium of a Surf Clam, Spisula (Pseudocardium) sachalinensis
Authors: Kikuchi Yasuo , Tamiya Nobuo 
Published: July 2006

Abstract
Sulfinyl group was detected in the resilium (internal hinge-ligament) of surf clam by IR spectrometry. The results reconfirm the previous reports on the presence of methionine S-oxide in the intact resilium protein. Aragonite structure was deduced for CaCO3 in the resilium because the IR spectrum of the resilium was reproduced from those of decalcified resilium and aragonite (CaCO3). The IR spectrum of intact protein component in the resilium was simulated from those of the resilium and aragonite (CaCO3).
Isolation and Assignment of Two Isomers of trans(NO2)-Dinitrobis[(S)-2-aminomethylpyrrolidine]cobalt(III) Perchlorate
Authors: Saburi Masahiko , Yokowo Yasuhiko , Yoshikawa Sadao 
Published: July 2006

Abstract
Two possible isomers (trans,cis and trans,trans) of trans-(NO2)-[(Co(NO2)2(ampr)2]ClO4 (ampr=(S)-2-aminomethylpyrrolidine) were isolated separately by fractional recrystallization. The dinitro complexes were converted to the corresponding trans(Cl,NO2)–[CoCl(NO2)(ampr)2]+ complexes. Based on the circular dichroism and 13C-NMR spectral data, it was shown that the less soluble dinitro complex gave the single isomer of the chloronitro complex, while the more soluble one yielded two diastereomeric chloronitro complexes. Thus, the former is assigned to the trans,cis configuration, and the latter to the trans,trans, taking the geometries of the complexes into consideration.
The Preparation of Dl-Isoleucine by Asymmetric Transformation
Authors: Hongo Chikara , Yoshioka Ryuzo , Tohyama Masanori , Yamada Shigeki , Chibata Ichiro 
Published: July 2006

Abstract
The chemical synthesis of isoleucine leads to a mixture of Dl-isoleucine and Dl-alloisoleucine. The preparation of Dl-isoleucine from the mixture was studied. When the mixture was reacted with 1,5-naphthalenedisulfonic acid in water, Dl-isoleucine formed the less soluble 1,5-naphthalenedisulfonate and could be separated in the form of the salt from the mixture. The soluble Dl-alloisoleucine salt was easily epimerized by heating in acetic acid in the presence of salicylaldehyde and free isoleucine mixture. Asymmetric transformation between the two diastereoisomeric racemates was carried out by the simultaneous combination of the fractional crystallization of the less soluble Dl-isoleucine salt and the epimerization of the soluble Dl-alloisoleucine salt. Dl-Isoleucine salt was obtained in a yield of up to 95% from a Dl-isoleucine–Dl-alloisoleucine mixture or even from Dl-alloisoleucine.
Sorption of Ammonia/Ammonium Ion on Crystalline Hydrous Titanium Dioxide Fibers
Authors: Sasaki Takayoshi , Komatsu Y\={u} , Fujiki Yoshinori 
Published: July 2006

Abstract
The sorption of ammonia/ammonium ion has been studied on crystalline hydrous titanium dioxide fibers with a layer structure, which are prepared from potassium tetratitanate (K2Ti4O9). From the measurement of the distribution coefficient, it was found that this material strongly preferred ammonium ion to sodium ion. The results of the pH titration curves indicated that this material showed a wide range of acidities toward ammonia/ammonium ion and had 2.63 mequiv/g of an apparent capacity which was about a half of the theoretical ion-exchange capacity. The characterizations of the ammonium adsorbed solid phase at various loading levels were carried out by measuring the X-ray powder diffractograms and the water contents. From these studies, it was concluded that the sorption-desorption reaction of ammonia/ammonium ion on this material took place almost reversibly in three stages.
Electronic Absorption, Magnetic Circular Dichroism, and Circular Dichroism Spectra of cis- and trans-[Pd(Cl)2(N)2]-type Complexes and Their Electronic Structures
Authors: Nakayama Kazuhiko , Komorita Takashi , Shimura Yoichi 
Published: July 2006

Abstract
The electronic absorption and MCD spectra of [PdCl2L] (L=ethylenediamine(en), 1,3-propanediamine, N,N-dimethylethylenediamine, N,N′-dimethylethylenediamine, N,N-diethylethylenediamine, and N,N-dimethyl-1,3-propanediamine) and trans-[PdCl2(L)2] (L=EtNH2, Me2NH, Me3N, n-BuNH2, i-BuNH2, s-BuNH2, t-BuNH2, and rac-pea (pea=1-phenylethylamine)), and CD spectra of [PdCl2L] (L=(S)-1,2-propanediamine-(S-pn) and (2S)-N1,N1-diethyl-1,2-propanediamine) and trans-[PdCl2(S-pea)2] have been measured over the visible-near UV region, together with the corresponding spectra of [PtCl2L] (L=en and S-pn). The examination of the three kinds of spectra as well as their Gaussian analyses indicates that the splitting pattern of metal d orbitals for the cis type complexes is similar to that for [PdCl4]2−, and that as to the trans complexes the dx2−y2←dxz and dyz transitions split largely to give apparent two spin-allowed d-d bands characteristic of the trans complexes. The average energy of the dx2−y2←dxz and dyz transitions for the trans complexes is approximately equal to the energy of the dx2−y2←dxz,yz (D4h) ones for the cis complexes. The transition energies of dx2−y2←dxy and dx2 do not differ largely between both types of complexes. The assignments of high-intensity bands have also been made tentatively.
Application of Gel Chromatography to Determining Formation Constants of Inclusion Compounds of Cyclodextrins
Authors: Sanemasa Isao , Mizoguchi Takemi , Deguchi Toshio 
Published: July 2006

Abstract
The gel filtration technique (Hummel and Dreyer method) was applied to determining formation constants of inclusion complexes of α- and β-cyclodextrins. As guest substances, p-nitrophenolate, p-nitrophenol, benzoate, and benzoic acid were used. Formation constants were determined at room temperature (25–30 °C) using Sephadex G-10 gel in aqueous buffered solutions of a constant ionic strength of 0.5 with NaCl or with phosphate buffer, and the results were compared with literature values. The method is applicable to such guest substances as exhibit strong adsorption onto the gel matrix.
Emergence of Nematic Phase in Purely Smectogenic Alkyl 4-(4-Substituted Benzylideneamino)benzoates by Chain Branching of the Ester Alkyl Group
Authors: Matsunaga Yoshio , Miyajima Nobuhiko 
Published: July 2006

Abstract
2-Methylation of the ester butyl and pentyl groups in the phenyl-substituted compounds and also of the ester propyl, butyl, and pentyl groups in a number of the alkoxy-substituted compounds resulted in the production of nematic liquid crystals.
Preparation and Characterization of the Diastereoisomers of the (S)- or (R)-1,2-Propanediaminebis(1,10-phenanthroline)cobalt(III) Ion
Authors: Tatehata Akira , Natsume Shigeru 
Published: July 2006

Abstract
Four diastereoisomers of the type [Co(S- or (R-pn)(phen)2]3+ (pn=1,2-propanediamine; phen=1,10-phenanthroline) were prepared and characterized by absorption, circular dichroism (CD), and 1H NMR spectra. High stereoselectivity in the formation of the diastereoisomers was observed and the Λ-isomer of [Co(S-pn)(phen)2]3+ was formed in preference to the Δ-isomer.
The Formation of 1,2-Bis(alkylthio)-1,2-diphenylethanes by the Lithium Diisopropylamide-induced Fragmentation of Dibenzyl Disulfide Followed by the Trapping with Some Alkyl Halides
Authors: Ikehira Hideyuki , Tanimoto Shigeo 
Published: July 2006

Abstract
It was found that dibenzyl disulfide undergoes lithium diisopropylamide-induced fragmentation to afford several intermediate species which, on trapping with alkyl halides, lead to the formation of 1,2-bis(alkylthio)-1,2-diphenylethanes and α-alkylbenzyl alkyl sulfides.
Ferromagnetic Interactions in Formazanyl–Copper Complexes
Authors: Kawamura Yoshiko , Ohya-Nishiguchi Hiroaki , Yamauchi Jun , Deguchi Yasuo 
Published: July 2006

Abstract
The magnetic susceptibility of four formazanyl–copper complexes have been measured by the use of a torsion balance in the range from 2 K to room temperature. Their ESR parameters have been measured on powdered samples at room temperature and the temperature of liquid nitrogen, and in solution at room temperature in order to elucidate the electronic structures of the complexes. The complexes which have shown the exchange-narrowed pattern in the spectra of powdered samples have been paramagnetic as low as 2 K. Nitro and carboxy derivatives characterized by a single, broad ESR absoption line have positive Weiss constants, indicating ferromagnetic interaction. Especially, the magnetic behavior of the carboxy derivative has been well interpreted in terms of a ground triplet-excited singlet model with the exchange parameter of 24 K. The nitro derivative showed an abnormally low magnetic moment. It has been concluded that the magnetic properties of formazanyl–copper complexes are very sensitive to substitution at the phenyl rings.
The Photoionization Mechanism of N,N,N′,N′-Tetramethyl-p-phenylenediamine in Acetonitrile
Authors: Nakamura Shigemasa , Kanamaru Nobuaki , Nohara Sawako , Nakamura Hiroki , Saito Yasuyoshi , Tanaka Jiro , Sumitani Minoru , Nakashima Nobuaki , Yoshihara Keitaro 
Published: July 2006

Abstract
The photoionization mechanism of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) in an acetonitrile solution was investigated by means of the fluorescence lifetime measurement, picosecond and nanosecond laser photolyses, and photocurrent measurement. The temperature dependence of the fluorescence lifetime was interpreted in terms of the thermally activated monophotonic ionization or the ion-pair-formation mechanism from the S1 excited level. Picosecond laser photolysis clearly showed that a direct ionization from higher S1,0 levels took place before relaxation into the S1.0 level. The relative yields of triplet, ion-pair, and cation formation were estimated from analyses of the transient spectra and the photocurrent.