bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Direct Alkylamination of α-Substituted Anthraquinones Promoted by Metal Ions
Authors: Matsuoka Masaru , Takei Toshio , Nakamura Isao , Yoshida Katsuhira , Kitao Teijiro 
Published: July 2006

Abstract
The reaction of 1-amino-4-acylaminoanthraquinones with piperidine in the presence of CoCl2 and atmospheric oxygen gave the 2-aminated products in 75–80%, and similar reaction of 1-hydroxyanthraquinone or 1-aminoanthraquinone-2-sulfonic acid with butylamine gave the corresponding 4-aminated products, respectively. The effects of the α-substituents and the role of metal salts were discussed.
A Novel Synthesis of Phenyl Carboxylates
Authors: Hashimoto Shizunobu , Furukawa Isao 
Published: July 2006

Abstract
The direct synthesis of phenyl carboxylates from phenols and carboxylic acids is reported. The reactions proceeded easily when triphenylphosphine and carbon tetrachloride were used as dehydrating agents in the presence of a tertiary amine at room temperature, thus giving esters in high yields.
Studies on Biologically Active Pteridines. VI. Biopterin Conjugated to β-d-Galactosidase and Bovine Serum Albumine
Authors: Matsuura Sadao , Sugimoto Takashi , Nagatsu Toshiharu 
Published: July 2006

Abstract
4-Hydroxy-6-(l-erythro-1,2-dihydroxypropyl)-2-(methylthio)pteridine was converted by ethylenediamine to 2-(2-aminoethylamino)analogue of biopterin, which condensed with N-hydroxysuccimidyloxy m-maleimidobenzoate to give the maleimidobenzamide. The latter compound and β-d-galactosidase afforded a biopterin-galactosidase conjugate which showed the enzyme activity about 40% as compared to the unmodified enzyme.
A Cationic [3,4] Sigmatropic Rearrangement
Authors: Nishizawa Mugio , Noyori Ryoji 
Published: July 2006

Abstract
The first example of the cationic [3,4]sigmatropic reaction has been achieved by the reaction of 1,3-dibromo-3-methyl-6-hepten-2-one and diiron nonacarbonyl.
Resonance Energies of the Arenium Ions and Their Relevance to the Electrophilic Substitution Reactions
Authors: Aihara Jun-ichi 
Published: July 2006

Abstract
Hyperconjugative interaction through the methylene group was incorporated in the framework of the Hückel molecular orbital model. Resonance energies of the arenium ions, derived from typical benzenoid hydrocarbons, were calculated using the graph theory of aromaticity. It was found that even a benzenium ion has a considerable degree of aromaticity. In general, the arenium ion with large localization energy has both large resonance energy due to hyperconjugation and large positive charge density at the methylene group. These two quantities are possibly responsible for the competition between substitution and addition reactions on the benzenoid hydrocarbons. An aromatic transition state tends to choose a reaction path to substitution products, at least, for these compounds.
Optical Properties of Undoped and AsF5 Doped “Poly(4,4′-biphenylylene)” Films
Authors: Watanabe Atsushi , Fujimoto Hitoshi , Tanaka Masashi , Tanaka Jiro 
Published: July 2006

Abstract
Optical absorption and reflection measurements are carried out on undoped and AsF5 doped films of “poly(4,4′-biphenylylene)” over a wide wavelength region (300–50000 cm−1). In the doped polymer, the free carrier absorption band appears in the IR region and the dc conductivity is estimated from the observed spectrum. The obtained value (σ0=376 S cm−1) is two orders of magnitude larger than the value (σ0=2 S cm−1) observed by the conductivity measurement. The discrepancy may be due to the existence of many cracks on the films.
Proton Equilibria of a 5-Dimethylamino-1-naphthalenesulfonyl Group Conjugated to Bovine Serum Albumin. I. Effects of The Conjugation on Structural Alternation
Authors: Ikuta Nobuo , Koga Joichi , Kuroki Nobuhiko 
Published: July 2006

Abstract
The proton equilibria of an optical probe, the 5-dimethylamino-1-naphthalenesulfonyl group, conjugated to bovine serum albumin with various molar ratios to the protein in an acidic solution, were investigated by means of the change in the fluorescence intensity as well as that in the absorbance. Below the molar ratio of 1.7 the apparent pK values for the dimethylamino moiety of the optical probe decreased remarkably with a decrease in the pH of the solution, accompanying conformational changes of the protein caused by the proton binding to the protein. For molar ratios of more than 2.0, the alternation of the higher structure of the protein induced by the conjugation of the probe was detected by ORD measurements, while the pK values of those conjugated probes were lowered at pH’s higher than 3.0. For comparison, the probe conjugated with glycine as its free state gave the pK value of 3.99 in an aqueous solution. The shifts of the apparent pK values of the conjugated probe in the protonated protein compared with those for the free probe were, particularly, too large to arise from the Debye-Hückel electrostatic shielding effect. These results are, therefore, interpreted in terms of a change in the shortrange interaction in the neighboring residues surrounding the probe.
Ion Association of Some 2:2 Electrolytes in Water at 25 °C. III. A New Interpretation of Experimental Results and the Determination of Formation Constants of Inner-sphere Ion-pairs
Authors: Yokoyama Haruhiko , Yamatera Hideo 
Published: July 2006

Abstract
The results of previous studies on ion association were re-examined. The formation constants of inner-sphere ion-pairs were obtained for several bivalent-metal sulfates by estimating the formation constants of outer-sphere ion-pairs with the help of the ion-association theory. The interactions between metal and sulfate ions were discussed by comparing these results.
A Novel Cationic Optically Active Complex of Platinum(II) Containing 2-Methyl-2-butene and o-Benzenediamine. The Circular Dichroism Spectrum and Kinetics of Olefin Exchange
Authors: Miya Shin’ya , Kashiwabara Kazuo , Saito Kazuo 
Published: July 2006

Abstract
An optically active cationic olefin complex, [PtCl(o-benzenediamine)((S)-2-methyl-2-butene)]B(C6H5)4 was obtained for the first time as crystal stable in air at room temperature. It deteriorates slightly in solution, but is still stable enough to be characterized. Comparison of its CD spectrum with that of related complexes disclosed that the coordinating atoms at the cis sites to the olefin have a dominant influence upon the CD pattern in the region 20000–35000 cm−1, as compared with those at the trans site. Substitution of cis-1,2-dichloroethylene for the coordinated (S)-2-methyl-2-butene (S-mbn) proceeds in accordance with the second order rate law; there is no contribution of the solvent path. The second order rate constant is smaller than that of trans-[PtCl2(pyridine)(S-mbn)]. The steric effect of the o-benzenediamine at the transition state seems responsible for the small rate rather than the basicity of the ligand at the trans site to mbn.
Five-coordinate Copper(II) Complexes with a Thio Group as Type II Copper Models
Authors: Sakurai Takeshi , Suzuki Shinnichiro , Nakahara Akitsugu 
Published: July 2006

Abstract
Five-coordinate copper(II) complexes with a thio group were synthesized as non-blue copper(II) models by reactions of copper(II) perchlorate and condensation products of 2-pyridinecarbaldehyde or salicylaldehyde and bis(2-aminoethyl) sulfide or 2-aminoethyl 3-aminopropyl sulfide. In the complexes where thio group is coordinated to copper(II) at an equatorial position, the ESR spin Hamiltonian parameters g⁄⁄ and A⁄⁄ prominently decreased, and charge transfer bands due to sulfur to copper appeared at 300–350 nm and occasionally at 400– 500 nm. On the other hand, complexes with a thio group at an axial position afforded slightly smaller A⁄⁄ values and charge transfer bands with lower intensity in the similar regions. The biological significance of a sulfur donation to non-blue copper(II) has been discussed.
Photochemical Reactions of Aromatic Compounds. XXXVI. The Photoreactions of Anthracene with Some Selected Tertiary Aromatic Amines in Polar Media
Authors: Yasuda Masahide , Pac Chyongjin , Sakurai Hiroshi 
Published: July 2006

Abstract
The photoreaction of anthracene with N,N-dimethylaniline in acetonitrile gave 9-(p-dimethylaminophenyl)9,10-dihydroanthracene in a good yield, along with 9,10-dihydroanthracene and 9,9′,10,10′-tetrahydro-9,9′-bianthryl. This photoreaction was found to depend on the polarity of the solvent as well as on its protic or aprotic nature. With N,N-dimethyl-m-toluidine, a similar 1 : 1 adduct was obtained, while the reduced anthracenes were mainly formed in the photoreactions with N,N-dimethyl-o- and p-toluidines. The mechanisms were discussed in terms of the dissociation into the ion radicals as well as their reactivities.
CIDNP Studies of the Thermal Decomposition of Arylazo Aryl Sulfones
Authors: Yoshida Masato , Furuta Naoki , Kobayashi Michio 
Published: July 2006

Abstract
1H-and 13C-CIDNP spectra were obtained during the thermal decomposition of several arylazo aryl sulfones (Ar–N=N–SO2–Ar′) in tetrachloroethylene or 1,1,2,2-tetrachloroethane at 100 °C. An enhanced absorption from the C1 of the starting material, azo sulfone, was observed; this indicates that the decomposition of azo sulfone proceeds by means of one-bond fission. The formation of sulfones (ArSO2Ar′) and sulfinic esters (ArO(SO)Ar′) as recombination products in a solvent cage was established from the signs of polarization (enhanced absorption or emission).
Epicubebol and Related Sesquiterpenoids from the Brown Alga Dictyopteris divaricata
Authors: Suzuki Minoru , Kowata Nobuhiko , Kurosawa Etsuro 
Published: July 2006

Abstract
Epicubebol has been isolated from the methanol extracts of the brown alga Dictyopteris divaricata as the major constituent. Cadinane-type sesquiterpenes, cubebenes, δ-cadinene, cubenol, and epicubenol, as well as two sesquiterpene methyl ethers as minor constituents have also been obtained from the extracts.
The Pschorr Cyclization of Aromatic Amines with t-Butyl Thionitrate in Nonaqueous Media
Authors: Oae Shigeru , Iida Kazuyuki , Shinhama K\={o}ichi , Takata Toshikazu 
Published: July 2006

Abstract
The Pschorr cyclization of various arylamines with t-butyl thionitrate under nonaqueous conditions gave the, corresponding cyclic products in moderate yields. The same reaction was also found to proceed readily with p-toluenesulfonyl nitrite at room temperature. Treatment of o-aminophenyl allyl ether or sulfide with t-butyl thionitrate resulted in the intramolecular Meerwein arylation to the olefinic bond affording 3-chlorochroman or -thiochroman, though the yield was low. The plausible mechanism of the Pschorr cyclization with t-butyl thionitrate is discussed.
Branched-chain Sugars. XXIV. Synthesis of Methyl 6-Deoxy-3-C-methyl-β-d-gulopyranoside (Methyl β-Virenoside)
Authors: Hong Namgi , Sato Ken-ichi , Yoshimura Juji 
Published: July 2006

Abstract
Methyl 6-deoxy-3-C-methyl-β-d-gulopyranoside (methyl β-virenoside) was prepared from d-galactose. An attempted synthesis of the virenoside by the inversion at C-4 of methyl 6-deoxy-3-C-methyl-α-d-allopyranoside was unsuccessful.
The Reaction of 2,4,6-Triphenyl-1,3-oxazinylium Perchlorate with Amino Compounds
Authors: Shibuya Isao 
Published: July 2006

Abstract
The reaction of 2,4,6-triphenyl-1,3-oxazinylium perchlorate with various kinds of amino compounds was studied. Primary amines and semicarbazides gave pyrimidinium perchlorates. o-Phenylenediamine, o-aminobenzamide, and o-aminothiophenol afforded 2,4-diphenyl-1,5-benzodiazepine, 2-phenyl-4-hydroxyquinazoline, and 2-phenyl-1,3-benzothiazole respectively. Benzoylhydrazine, 4-pyridinecarbohydrazide, and 4-phenylthiosemicarbazide all led to pyrazoline derivatives. N,N-Dimethylhydrazine yielded two chain products competitively, while N,N′-dimethylhydrazine gave 1,2-dimethyl-3,5-diphenyl-1,2,4-triazolylium and 1,2-dimethyl-3,5-diphenylpyrazolylium perchlorate competitively. It was thus shown that 2,4,6-triphenyl-1,3-oxazinylium perchlorate reacts with amino compounds in a complicated fashion to afford various heterocyclic compounds and other derivatives.
The Determination of the Chemical Diffusion Coefficient of n-Type AgBr by Means of a D.c. Polarization Cell
Authors: Sasaki Jun , Mizusaki Junichiro , Yamauchi Shigeru , Fueki Kazuo 
Published: July 2006

Abstract
The electronic conductivity of AgBr and the chemical diffusion coefficient of n-type AgBr were measured by means of a d.c. polarization cell, \ominus Ag/AgBr/inert electrode ⊕, in the temperature range from 325 °C to 400 °C. In order to suppress the electrolysis of AgBr, a platinum plate was used instead of carbon as the inert anode. The chemical diffusion coefficient, \ ildeD, was determined by two methods. One was the intermediate probe method (IP method) whereby the relaxation of the voltage between the Ag reversible electrode and the Pt intermediate probe, inserted into the middle of AgBr, was followed after an abrupt change in the polarization voltage. The other was the open-circuit method (OC method) whereby the terminal voltage of the cell was followed after the circuit of the cell had been opened. The electronic conductivity in the steady state was independent of the nature of the inert electrodes (Pt or C), provided that the inert electrode was completely sealed. However, it took more time for the cell with a carbon electrode to reach the steady state than that with a platinum one. The chemical diffusion coefficient, \ ildeD, determined by the IP method for the Ag/AgBr/Pt cell agreed with that for the Ag/AgBr/C cell. The chemical diffusion coefficient, \ ildeD, determined by the OC method for the Ag/AgBr/Pt cell agreed with that obtained by the IP method. The chemical diffusion coefficients determined by these methods were expressed by
\ ildeD=3.0×103exp\left(\frac−89.9 kJ mol−1RT\ight)⁄cm2 s−1.
No chemical diffusion coefficient can be obtained by the OC method for the Ag/AgBr/C cell, because of the slow diffusion of the Br2 gas produced by the electrolysis of AgBr from the carbon electrode.
Applications of Homogeneous Water-gas-shift Reaction. I. Further Studies of the Hydroformylation of Propene with CO and H2O
Authors: Murata Kazuhisa , Matsuda Akio 
Published: July 2006

Abstract
Polar ether solutions prepared in situ from Co2(CO)8 and 1,2-bis(diphenylphosphino)ethane (diphos) are active catalysts for the hydroformylation of propene with CO and H2O. Under the hydroformylation conditions employed, butyl (C4) or isobutyl alcohols, butyric (C4) acids, and dipropyl ketones were found to be formed as by-products. A pronounced formation of C4 alcohols was observed as the reaction temperature was increased; in fact, the catalyst solutions described above actively reduce butyraldehyde to butyl alcohol. The effects of the CO pressure and of the propene concentration on the formation of C4 aldehydes are also examined. It turns out that the water molecule as well as Co2(CO)8 and diphos are essential for the formation of catalytic intermediates, which are themselves responsible for the hydroformylation activity.
An Electron Spin Resonance Study of the Phosphorescent Triplet State of Poly(vinylnaphthalene)s
Authors: Higuchi Jiro , Yagi Mikio , Saito Juichiro , Takanashi Midori 
Published: July 2006

Abstract
The electron spin resonance (ESR) of poly(1-vinylnaphthalene) and poly(2-vinylnaphthalene) in their phosphorescent triplet states is studied in glassy solutions and in plastic hosts. The zero-field splitting parameters thus obtained are discussed in comparison with those of 1- and 2-methylnaphthalene. Through the ESR measurement, the possibility of detecting the triplet energy transfer through the naphthyl groups is examined.
Electrode Kinetics of the Redox Couples of Co(III/II) Complexes with Ethylenediamine-N-acetate, Iminodiacetate, and Diethylenetriamine
Authors: Ohsaka Takeo , Oyama Noboru , Yamaguchi Shuichiro , Matsuda Hiroaki 
Published: July 2006

Abstract
The electrochemical kinetic parameters of Co(edma)21+⁄0 (edma: ethylenediamine-N-acetate), Co(ida)21−⁄2− iminodiacetate), Co(dien)23+⁄2+ (dien: diethylenetriamine), Co(1,2-pn)33+⁄2+ (1,2-pn: 1,2-propanediamine), and Co(gly)30⁄1− (gly: glycinate) redox couples were determined by d.c. and normal pulse polarographic measurements as well as galvanostatic double pulse measurements. A difference in the evaluated kinetic parameters for the geometric isomers, trans(O)- and cis(O)-Co(edma)21+⁄0 and trans(N)- and cis(N)-Co(ida)21−⁄2− couples, was recognized. The values of the standard rate constant for the bis forms with dien, edma, and ida were reduced with increase in the number of replacement of amino groups in dien by carboxyl groups. The standard rate constants of the redox couples of Co(III/II) complexes with a series of bi- and tridentate polyamines and aminocarboxylates increase in proportion to the number of nitrogen donor atoms involved in the ligands.
Formation of Micelles of Acylcarnitines in Glycerol
Authors: Ionescu Lavinel G , Fung Daniel S 
Published: July 2006

Abstract
Acylcarnitine chlorides form micelles in water and polyprotic solvents such as glycerol, ethylene glycol; 1,3-propanediol and 1,4-butanediol. The effect of the acyl chain on the formation of micelles was studied for compounds with chain lengths of 2 to 16 carbon atoms. The critical micellar concentration in glycerol was determined at 25 °C by means of difference spectroscopy using phenol as a probe. The acylcarnitine chlorides with chains containing less than 8 C atoms do not form micelles in glycerol. The critical micellar concentration varies from 0.060 mol dm−3 for octanoylcarnitine to 0.011 mol dm−3 for palmitoylcarnitine. The free energy of micellization, ΔGmic°, varies linearly with chain length in the range of −6.95 kJ mol−1 to −11.2 kJ mol−1. The “hydrophobic” or “solvophobic” effect was more pronounced in water than in glycerol and the free energy change per metylene group was −2.89 kJ mol−1 and −0.75 kJ mol−1, respectively. The formation of micelles of acylcarnitine chlorides in glycerol is important in terms of the metabolism of fatty acids and their transport across biological membranes.
Peroxomonophosphoric Acid Oxidations. VI. Kinetics and Mechanism of Oxidation of 3-Aminopyridine
Authors: Mahapatro Surendra Nath , Panda Abhina Kumar , Panigrahi Ganesh Prasad 
Published: July 2006

Abstract
The oxidation of 3-aminopyridine to 3,3′-azoxypyridine by peroxomonophosphoric acid (PMPA) is a total second order reaction: first order each in peroxomonophosphoric acid and 3-aminopyridine at constant acidity. The observed pH-rate profile has been rationalized invoking various PMPA species, protonated and unprotonated forms of 3-aminopyridine as the reactive species and their reactivities have been estimated. Interestingly, 2-aminopyridine is not oxidized in the pH-range where the oxidation of 3-aminopyridine is facile.
The Crystal and Molecular Structure of 2-Acetoxy-2-methyl[1,3]dioxolo[4,5-c]isoquinoline-5-carbonitrile. A Photoproduct of 1,4-Diacetoxy-2,3-diazidonaphthalene
Authors: Kitano Yukishige , Ashida Tamaichi , Yabe Akira 
Published: July 2006

Abstract
The crystal of the title compound is triclinic, with a space group of P\bar1 and with two molecules per unit cell with dimensions of a=8.317 (2), b=11.191 (1), c=7.731 (1)Å, α=105.91 (1), β=103.76 (2), and γ=102.60 (1)°. The fused isoquinoline and dioxolane rings lie on nearly the same plane; the non-hydrogen atoms of the acetoxyl and methyl groups make another plane. These two planes make an angle of 92.0° with each other.
On the Additivity of Molar Volume and Refractivity of Molten Ca(NO3)2·3.18H2O–KSCN System
Authors: Mahiuddin Sheik , Ismail Kochi 
Published: July 2006

Abstract
Densities and refractive indices of Ca(NO3)2·3.18H2O-KSCN melts have been measured as functions of temperature and composition. Densities, molar volumes, and refractive indices show linear dependence on temperature. Molar volume, intrinsic volume, molar refractivity, and the product of refractive index and molar volume show additivity within ±2% error. The molten Ca(NO3)2·3.18H2O–KSCN system at ambient temperatures appears to behave like an ideal mixture of molten Ca(NO3)2·3.18H2O and supercooled KSCN melt.
A New Synthetic Route to Electrophilic Cyclopropane Derivatives from Olefins
Authors: Kawabata Nariyoshi , Yano Shinji , Hashimoto Jiro , Yoshida Jun-ichi 
Published: July 2006

Abstract
1,1-Bis(alkoxycarbonyl)-, 1-alkoxycarbonyl-1-cyano-, and 1,1-dicyanocyclopropane derivatives were obtained in 10–99% yields by the reaction of Br2C(COOR)2, Br2C(CN)(COOR), and KBr[Br2C(CN)2]4, respectively, with olefins and Cu2Br2 in dimethyl sulfoxide (DMSO).
Facile Intramolecular Cyclization Reactions of Aromatic Ethers with Cationoids in Triptycene Systems
Authors: Izumi Giichi , Hatakeyama Shiro , Nakamura Nobuo , Oki Michinori 
Published: July 2006

Abstract
1,4-Dimethoxytriptycenes were found to give cyclic ethers with unusual ease when a substituent at the bridgehead bears a cationoid center. The easy reaction is attributed to the extreme proximity between the methoxyl group and the cationic center. Mechanisms involving a cyclic oxonium ion and subsequent attack by an anion to produce the cyclic ether and a methyl derivative are discussed.
Mechanochemical Change in the Solid State and the Solubility of Amobarbital
Authors: Ikekawa Akiko , Hayakawa Sohachiro 
Published: July 2006

Abstract
Influence of ball-milling on the X-ray diffraction pattern, the thermal properties, the IR spectra, the particle size distribution and the solubility of amobarbital was investigated. The fraction of crystal I decreased, and the fraction of crystal III and the amorphous part increased at the first stage of ball-milling. The heat of fusion decreased slightly by ball-milling, which was considered to be due to the increase in the fraction of the amorphous part. The melting point lowered by 1–3 °C and the NH and CO absorptions in the IR spectra were influenced by ball-milling, which was considered to be due to the transformation of crystal I into crystal III. The particle size decreased at the first stage of ball-milling. It was considered that the transformation of crystal I into crystal III was remarkable when the particles were broken. The solubility of amobarbital in the KH2PO4–Na2HPO4 buffer solution with pH of 6.0 increased by ball-milling, which was considered to be due to the increase in the fraction of the amorphous part and crystal III.
Pressure Effect on Rate Constants of Proton-transfer Reactions from 2,4,6-Trinitrotoluene to N,N,N′,N′-Tetramethylguanidine and 1,8-Diazabicyclo[5.4.0]undec-7-ene in Acetonitrile and Dichloromethane
Authors: Sugimoto Naoki , Sasaki Muneo , Osugi Jiro 
Published: July 2006

Abstract
Influence of pressure on the rate constants of the proton-transfer reactions between title compounds was studied in acetonitrile and dichloromethane at 25 °C up to 1000 bar by means of a high-pressure stopped-flow method. In the reaction of 2,4,6-trinitrotoluene (TNT) with N,N,N′,N′-tetramethylguanidine, the volume of activation for the forward reaction ΔVf\eweq is −12.7±1.0 cm3 mol−1 in acetonitrile and −19.0±1.5 cm3 mol−1 in dichloromethane. In the reaction of TNT with 1,8-diazabicyclo[5.4.0]undec-7-ene, ΔVf\eweq is −9.0±1.0 cm3 mol−1 in acetonitrile and −10.8±1.0 cm3 mol−1 in dichloromethane. These results are discussed in comparison with other proton-transfer reactions.
Pressure Dependence and Cationic Radius Effect of the Glass Transition Temperature in Aqueous Alkali Acetate Solutions
Authors: Kanno Hitoshi , Shirotani Ichimin , Minomura Shigeru 
Published: July 2006

Abstract
The glass transition temperature (Tg) is measured as a function of pressure up to 200 MPa for the aqueous Li, Na, K, Rb, and Cs acetate solutions. The effects of cation radius on the glass transition of these solutions are discussed and some attempts are made to correlate Tg (and associated properties) with r (cation radius).