bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conformation of Thymidine 3′,5′-Cyclic Phosphate in Aqueous Solution. Compatibility of the Information from the Lanthanide-Ion Probe and the Spin-Coupling Constants
Authors: Inagaki Fuyuhiko , Takahashi Seizo , Tasumi Mitsuo , Miyazawa Tatsuo 
Published: July 2006

Abstract
The Pr(III)- and Eu(III)-induced shifts of 1H nuclear magnetic resonances of thymidine 3′,5′-cyclic phosphate were observed in D2O solution. The results indicated that the induced shifts were primarily of dipolar origin and that the magnetic susceptibility tensor had effective axial symmetry. The ratios of shifts intrinsic to the lanthanide-substrate 1 : 1 complex were determined after correcting for the contributions of the complex formation shifts (diamagnetic terms). The Gd(III)-induced perturbations of the spin-lattice relaxation times were also observed, and the ratios of relaxation rates were obtained. A computer search was then performed to find out the molecular conformation of this cyclic nucleotide which best fitted the shift and relaxation ratios. As a result the phosphate-ring part was found to have a typical chair conformation. The effective symmetry axis of the magnetic susceptibility tensor coincided with the bisector of the OPO angle almost completely. It was rather difficult, however, to establish the conformation of the deoxyribose ring from the shift and relaxation ratios alone. The use of the additional information from the vicinal 1H–1H coupling constants (J1′2′ and J1′2″) was necessary for obtaining a reasonable conformation of the entire molecule. The compatibility of the information from the lanthanide-ion probe and the spin coupling constants (3JHH other than J1′2′ and J1′2″ and 3JHP) is discussed along with the limitations of both methods.
Formation of Oxygen Deficient Pyrochlore Solid Solutions Pb2Ta2−2xM2xO7−x(M=Ti, Sn and Zr) and Their Optical and Dielectric Properties
Authors: Torii Yasuyoshi , Matsumoto Hideo 
Published: July 2006

Abstract
It was found that oxygen deficient pyrochlore solid solutions Pb2Ta2−2xM2xO7−x with M=Ti, Sn, and Zr exist over wide ranges. The formation of oxygen deficient pyrochlore structure results from the occupancy of Pb2+ ions in the A position, which have a high polarizability. Their reflectance and infrared absorption spectra, and dielectric constants were measured. With the increase of M4+ ions, the color turned lemon yellow to reddish yellow, and the dielectric constants increased. The infrared absorption spectra in their pyrochlore solid solutions were similar to those in PbTiO3 and PbZrO3. The infrared properties of two strong absorption bands observed were discussed in comparison with those in the perovskites.
The Catalytic Action of a Mixed Micelle of Lauroylamino Acid and a Detergent
Authors: Inoue Tohru , Nomura Kazuo , Kimizuka Hideo 
Published: July 2006

Abstract
The catalytic effect of the mixed micelles of lauroylamino acids (LauAm) and detergents on the hydrolysis of p-nitrophenyl acetate has been studied. The amino acids used for the synthesis of LauAm were glycine, serine, histidine, tyrosine, lysine, and arginine. Cetyltrimethylammonium bromide (CTAB), polyoxyethylene dodecyl ether (C12E6) and sodium dodecyl sulfate (SDS) were used for the preparation of the mixed micelles with LauAm. Among the detergents used, only CTAB remarkably enhanced the catalytic activity of LauAm. A reaction scheme was proposed, and the rate constant for the catalytic activity of LauAm was estimated from the kinetic data. The effect of pH was also studied. Discussions were given of the mechanism of the catalytic action on the basis of the present study.
Furan Derivatives. II. The Cyclization of 3-(Benzofuran-3-yl)propionic Acid Derivatives
Authors: Horaguchi Takaaki , Shimizu Takahachi , Abe Teishiro 
Published: July 2006

Abstract
A compound, 6-methoxy-2a,3,4,5-tetrahydro-2H-naphtho[1,8-bc]furan-5-one (XX), was prepared in a 72% yield by heating 3-(5-methoxy-2,3-dihydrobenzofuran-3-yl)propionic acid (XIX) with polyphosphoric acid. However, when 3-(5-methoxybenzofuran-3-yl)propionic acid (IX) or 3-(2-benzoyl-5-methoxybenzofuran-3-yl)propionic acid (XIII) were treated with polyphosphoric acid, the product was 7-methoxy-2,3-dihydro-1H-cyclopenta[b]benzofuran-3-one (XI) rather than the corresponding naphtho[1,8-bc]furan derivatives, Also, neither naphtho[1,8-bc]furan nor cyclopenta[b]benzofuran derivatives were obtained from 3-(2-benzyl-5-methoxybenzofuran-3-yl)propionic acid (XIV) or 3-(2-ethyl-5-methoxybenzofuran-3-yl)propionic acid (XVII).
The Catalytic Effect of Crown Ethers on Benzoin Condensation
Authors: Akabori Sadatoshi , Ohtomi Michiko , Arai Katsuhiko 
Published: July 2006

Abstract
Aromatic aldehydes were treated with potassium cyanide in the presence of a crown ether in water or in aprotic solvents to give benzoins in high yields, although similar reactions in the absence of the crown ether proceeded sluggishly in general. The catalysis is believed to be due to the ability of the crown ether to bring anions into the organic phase.
The Thermal Reaction of Azoxybenzenes
Authors: Shimao Ichiro , Hashidzume Hirokazu 
Published: July 2006

Abstract
Azoxybenzenes (1) were heated at 245–250 °C to give azobenzenes (2), 2-hydroxyazobenzenes (3), 2-hydroxy-azoxybenzenes (4), 4-hydroxyazobenzenes (5), and 4-hydroxyazoxybenzenes (6). Compounds 4 and 6 were mostly composed of α-isomers. In the reaction of azoxytoluenes, their methyl groups were oxidized to formyl groups. It was proposed that 4 and 6 were the intermediates of the thermal rearrangement of 1 to 3 and 5.
The Crystal Structure of 1-(2-Thiazolylazo)-6-bromo-2-naphthol
Authors: Kurahashi Masayasu , Fukuyo Makoto , Shimada Akira , Kawase Akira 
Published: July 2006

Abstract
The crystals of 1-(2-thiazolylazo)-6-bromo-2-naphthol are orthorhombic, with a space group of P212121, and with unit-cell dimensions of a=19.044(3), b=31.996(9), c=4.221(1) Å, and z=8. The crystal structure was solved by the heavy-atom method and refined by the least-squares technique to give an R value of 0.064 for 1608 observed reflections. Both of the two crystallographically independent molecules show a generally similar shape and size. The phenolic oxygen atom is linked to the azo nitrogen atom adjacent to the thiazole ring by intramolecular hydrogen bonding, the O···N distances being 2.54 Å.
ESR Studies of Nitrobenzene Ion-Pair Equilibria in N,N-Dimethylformamide
Authors: Toshima Shinobu , Itaya Kingo 
Published: July 2006

Abstract
The hyperfine splitting constants of the nitrobenzene radical anion in DMF vary with the type of the counter cations and the concentrations. The tendency of these variations is related to the shift of the half-wave reduction potential of nitrobenzene. The variation of the nitrogen 14N hyperfine splitting constant is attributable to the formation of ion pairs involving the nitrobenzene radical anion and its counter cation. The ion-pair formation constants were evaluated from the changes in the hyperfine splitting and are completely consistent with those obtained from polarographic studies.
The Differences in Surface and Catalytic Properties of Two Magnesium Oxides Prepared from the Hydroxide and the Carbonate Hydroxide
Authors: Hattori Hideshi , Shimazu Katsuaki , Yoshii Naoji , Tanabe Kozo 
Published: July 2006

Abstract
Two kinds of MgO were prepared; MgO(I) from magnesium hydroxide and MgO(II) from magnesium carbonate hydroxide by evacuating at various temperatures and their surface and structural properties and catalytic actions for alkylation and isomerization reactions were examined. IR spectra of CO2 retaining or adsorbed showed broad bands on MgO(II), but relatively sharp bands on MgO(I). In the alkylation of phenol with methanol over MgO(I), phenol was selectively alkylated at the ortho positions to produce o-cresol and 2,6-xylenol. The ortho-selectivity of MgO(I) was higher than 96%, while that of MgO(II) was about 75%. A low selectivity of MgO(II) was considered to be caused by a heterogeneity of surface structure of MgO(II), which was suggested by broad IR bands of CO2 species on MgO(II). For the isomerization of 1-butene, both of MgO became active when evacuated at 450 °C and showed maximum activities when evacuated at 600 °C. The activity and the selectivity (ratio of cis-2-butene to trans-2-butene) of both catalysts were not much different. However, for the isomerization of cis-2-butene, the maximum activity and the selectivity (ratio of trans-2-butene to 1-butene) of MgO (I) were about four times higher than those of MgO(II).
Preparations and Properties of Some Gationic Palladium(II) Complexes of the Di-t-butylnitroxide Radical
Authors: Okunaka Masaaki , Matsubayashi Gen-etsu , Tanaka Toshio 
Published: July 2006

Abstract
Cationic palladium(II) complexes of the di-t-butylnitroxide radical, [Pd(But2NO)(L-L)]X (L-L=2,2′-bipyridine, 1,10-phenanthroline, N-substituted 2-pyridylmethyleneamine and bis(triphenylphosphine); X−=ClO4-and/or BPh4−), were prepared. 1H NMR spectra of the complexes indicate that the nitroxide forms a three membered ring with the palladium atom. The N-methyl- and N-ethyl-2-pyridylmethyleneamine complexes exist as two geometrical isomers in solution, whose ratios are 1 : 1 and 1 : 0.2, respectively. In the N-butyl and N-p-tolyl analogs, however, only one of the isomers exists in solution. These results are interpreted in terms of steric repulsion between the t-butyl groups and N-substituents. The bipyridine complex reacts with dialkyl disulfides in the presence of catalytic amounts of bipyridine to give a sulfur-bridged dimeric complex, [Pd(bipyridine)(SR)]2(ClO4)2(R=Me and Pr), and a free nitroxide radical.
Photochemical Valence Bond Isomerization of Some Benzo-C9H10 Hydrocarbons
Authors: Kato Masahiko , Chikamoto Takeji , Miwa Toshio 
Published: July 2006

Abstract
Studies have been carried out on the photochemical valence bond isomerization of some benzobicyclo-C9H10 hydrocarbons, i. e., benzo[8,9]bicyclo[5.2.0]nona-2,4,8-triene (2), benzo[2,3]bicyclo[6.1.0]nona-2,4,6-triene (3), cis-3a,9b-dihydro-1H-benz[e]indene (6), and benzo[6,7]bicyclo[3.2.2]nona-2,6,8-triene (10), with use of a low pressure mercury lamp. From a comparison of photolysis at low temperatures with that at room temperature, the stereochemical courses are discussed in terms of conformations of these compounds.
The Application of the Spin Trap, Phenyl t-Butyl Nitrone, to the Study of the γ-Radiolysis of Cyclohexane
Authors: Iwahashi Haruo , Ishikawa Yo-ichi , Sato Shin , Koyano Kinko 
Published: July 2006

Abstract
It was shown that cyclohexyl radicals formed by the γ-radiolysis of cyclohexane were trapped by phenyl t-butyl nitrone (PBN) to give a nitroxide with a well defined ESR spectrum. We measured the yield of this nitroxide. In order to establish the radical and electron scavenging properties of PBN, we measured the effect of this compound on the yields of hydrogen and nitrogen by adding dinitrogen oxide in cyclohexane together with PBN. The results suggested that PBN is able to scavenge not only free radicals but also electrons. The following relative rates were obtained: k(e−+PBN→PBN−)/k(e−+N2O→N2O−)=0.7 and k(H+PBN→HPBN)/k(H+C6H12→H2+C6H11)≈200 at room temperature. The G-value of the scavengeable hydrogen atoms from cyclohexane was estimated to be 3.4±0.4.
Dynamic Structure of Water in Aqueous Solutions of Chloroacetate. I. Temperature Dependence of Limiting Mobilities of Mono-, Di-, and Tri-chloroacetate Ions
Authors: Ebina Satoshi , Uedaira Hisashi 
Published: July 2006

Abstract
Electric conductivities of the sodium salts of mono-, di-, and tri-chloroacetic acids were measured in water at 15, 25, and 35 °C. The molar conductivities were analyzed by the Fuoss-Onsager equation to obtain the limiting mobility. On the basis of the temperature dependence of the limiting mobilities, the dynamic structure of Water around these anions was investigated by means of Samoilov’s theory, Chloroacetate ions are structure maker and the degree of the positive hydration is in the order TCA−&gt;acetate ion&gt;DCA−&gt;MCA−. From the results, it is shown that a competition between the different orientation of water molecules in the surroundings of –CH2Cl and –CHCl2 groups occurs, and consequently, shown that the water molecules around DCA− and MCA− ions more mobile than those around TCA− and acetate ions.
Dialkylpalladium(II) Complexes. Syntheses, Characterizations, and Reactions with CO, I2, and CH3I
Authors: Ito Takashi , Tsuchiya Hirotaka , Yamamoto Akio 
Published: July 2006

Abstract
The reaction of bis(acetylacetonato)palladium(II), [Pd(acac)2] with AlR2(OEt) in the presence of tertiary phosphine, L, in diethyl ether yields a series of dialkylpalladium(II) complexes, [PdR2L2], where R=Me, Et, and Prn; L=PEt3, PPh2Me, and 1/2Ph2PCH2CH2PPh2 (dpe). These complexes were characterized by means of elemental analysis, IR and 1H-NMR spectra and of some decomposition reaction such as thermolysis and acidolysis. The trans- and cis-configurations of [PdMe2L2] (L=PEt3 and PPh2Me, respectively) in solution were established on the basis of the 1H-NMR spectra. The examination of 1H-NMR spectra in the presence of tertiary phosphine suggests the ligand exchange processes promoted by the added phosphine. [PdR2L2] (L=PEt3 and PPh2Me) reacted with CO in toluene to yield the quantitative amounts of the corresponding dialkyl ketones. The reactions of the complexes [PdR2L2] with iodine afforded [PdI2L2] and RI, and of [PdR2(dpe)] with MeI gave CH3H, CH3CH3, R(–H), RH, R·CH3, R·R, and RI together with [PdI2L2], suggesting the presence of a quadrivalent, six-coordinate intermediate palladium species.
Polarographic Studies of Several Metal Ions in the Molten Salts of KNO3–LiNO3–NaNO3
Authors: Saito Makoto , Miura Tamio 
Published: July 2006

Abstract
The polarographic waves of Pb(II), Cd(II), Zn(II), and Tl(I) ions in molten salts of KNO3–LiNO3–NaNO3 were measured by means of d.c. polarography, using an Ag/AgNO3 reference electrode. The half-wave potential of metal ions was shifted toward more negative values in comparison with those in a nitrate melt containing no Li(I) ion.
Simple Relations between Scattering Cross Sections and Molecular Diameters
Authors: Oono Yoshitsugu , Nishimura Yukio 
Published: July 2006

Abstract
Empirical linear relations between the square roots of the electron-scattering cross sections for molecules and the cube roots of the van der Waals volumes for molecules due to Bondi are shown. The relations allow one to estimate, for example, the electron-impact ionization cross sections at 75 eV to within an error of ±15%. A dimensional analytic explanation of the relations is given.
Studies on the Thermal Separation Column. V. Thermal Separation Column Having Horizontal Barriers
Authors: Sasaki Kazuo , Tao Seiji , Hirano Yoshio 
Published: July 2006

Abstract
The performance of a hot wire type thermal separation column in which many horizontal barriers of Teflon or copper plates are installed has been examined. At the optimum spacing of barrier plates, the quality factor defined by (2AL)barrier/(2AL)open exceeds 3. This means that a barrier column constructed properly has a performance equivalent to that of an open column of three times taller in height. Visualization of a stream line in the barrier assembly indicates that a helical transverse motion takes place in the space partitioned by two adjacent barrier plates.
The Crystal and Molecular Structure of dl-2-cis-4-trans-Abscisic Acid
Authors: Ueda Hideo , Tanaka Jiro 
Published: July 2006

Abstract
The crystal and molecular structure of dl-2-cis-4-trans-abscisic acid has been determined by the X-ray method. The crystal is monoclinic, P21/c, with lattice parameters a=6.316(1), b=33.575(3), c=7.607(1) Å, and β=118.42(1)°. The molecule has two independent conjugated systems forming respective planes which are orthogonal to each other. The molecules form a dimer by the hydrogen bonding and are connected by the other hydrogen bonding along the c-axis.
N-Alkylation of Nitrogen Heterocyclic Compounds with Dialkyl Phosphites
Authors: Hayashi Masahiro , Yamauchi Kiyoshi , Kinoshita Masayoshi 
Published: July 2006

Abstract
Dialkyl phosphites were found to be efficient alkylating agents for various nitrogen heterocyclic compounds, especially for imidazole analogs and pyridones, producing the corresponding N-alkyl derivatives.
Nucleoside Analogs. 4. Synthesis of 3′-Amino-3′-deoxyadenosine Analogs
Authors: Tadano Kin-ichi , Emori Yasufumi , Ayabe Mitsukuni , Suami Tetsuo 
Published: July 2006

Abstract
Three 9-(3-amino-2,4,5-trihydroxycyclopentyl)adenines and their N-acyl derivatives were prepared as carbocyclic analogs of 3′-amino and 3′-acetamido-3′-deoxyadenosine from the three diastereomers of diaminocyclopentanetriol and 4-amino-6-chloro-5-nitropyrimidine.
The Reactions of the Nitrogen Atom with Ethylene and Ethylene-d4
Authors: Takahashi Saku , Miyazaki Shozo 
Published: July 2006

Abstract
In the N–C2H4 system, the main final product was HCN, and the stoichiometry (ΔN/HCN) of the reaction was about 1.3. In the N–C2D4 system, CD2 and CD2N were found as the reactive intermediates. We suggested a mechanism different from that proposed by Herron.
Construction of a 3He Calorimeter and Heat Capacity Measurement of the 1965 Calorimetry Conference Copper Standard between 0.4 and 20 K
Authors: Arai Naoto , Sorai Michio , Suga Hiroshi , Seki Syûzô 
Published: July 2006

Abstract
Construction of an isoperibol-type calorimeter with a 3He cryostat is described. A system of charcoal-adsorption-pump is adopted. A Ge-thermometer used in the heat capacity measurements is calibrated in the temperature range from 0.4 to 1.5 K against the magnetic susceptibility of chromium potassium alum. The precision and the accuracy of the calorimeter is ascertained by the heat capacity measurement of the 1965 Calorimetry Conference Copper Standard (T-8.6) in the temperature range from 0.420 to 19.46 K. The deviation of the experimental points from the “copper reference equation” is within the experimental error of ±2.5% between 0.4 and 0.9 K, ±1.5% between 0.9 and 1.5 K, ±1.2% between 1.5 and 4 K, and ±0.6% between 4 and 20 K. The highest deviation of absolute value of the present heat capacity data of copper is 1.86% smaller than the “selected values (Furukawa et al.)” around 6 K. This difference may be primarily attributable to the NBS-65 temperature scale adopted in the present experiment.
Preparation and Stereochemistry of trans-Dianionocobalt(III) Complexes with (S)-2-(Methylaminomethyl)pyrrolidine
Authors: Kitamura Taku , Sato Yoshiko , Saburi Masahiko , Yoshikawa Sadao 
Published: July 2006

Abstract
trans-Dinitro and dichloro cobalt(III) complexes containing (S)-2-(methylaminomethyl)pyrrolidine (N-Me-ampr) were prepared. Their stereochemistry differs a great deal from that of other N-methylated 1,2-diamines. The N-Me-ampr complexes prefer the trans,cis instead of the trans,trans configuration, the axial N-methyl groups being fairly stabilized. In the case of the dinitro complex, only one isomer which has the axial N-methyl groups, was isolated, but in the case of the trans-dichloro complex two diastereomers (trans,cis(RR) and trans,cis(SS)) were obtained. These dichloro isomers were slowly converted into an equilibrium mixture in methanol. The CD spectral data of the equilibrium mixture show that the trans,cis(RR) is more stable than the trans,cis(SS) isomer (−ΔG=0.4 kcal/mol).
α,β-Unsaturated Carboxylic Acid Derivatives. XII. A Convenient Synthesis of Oxazole-4-carboxylic and 3,3-Dibromo-2,2-diamino Acids
Authors: Shin Chung-gi , Sato Yoshiaki , Sugiyama Hidetoshi , Nanjo Katsumi , Yoshimura Juji 
Published: July 2006

Abstract
Treatment of t-butyl 2-acetylamino-3-bromo-2-alkenoate with triethylamine gave t-butyl 5-alkyl-2-methyloxazole-4-carboxylate by dehydrobromination, but no reaction occurred with primary amines. While treatment of t-butyl 2-acetylimino-3,3-dibromoalkanoate with hydroxylamine or several aliphatic and aromatic primary amines gave addition products, t-butyl 2-acetylamino-3,3-dibromo-2-(hydroxyamino)- and 2-(substituted amino)alkanoate, respectively, in fairly good yields.
Oxidation of 2,6-Piperazinediones
Authors: Tanaka Tatsuo , Yamazaki Hiroaki , Ohta Masaki 
Published: July 2006

Abstract
1,4-Disubstituted 2,6-piperazinediones (1) are susceptible to oxidation at the methylene group in the piperazine ring, giving piperazinetetrone (4) on being treated with selenium dioxide in boiling dioxane. Treatment of 1,4-diphenyl-2,6-piperazinedione (1a) with either nitrobenzene or tosyl chloride and triethylamine in benzene gives cyclic dimer (9) of dehydrogenated 1a. Cycloadduct (10) is obtained in the presecne of N-phenylmaleimide. It seems that both 9 and 10 are formed via labile mesoionic intermediate (8). Piperazinedione (1a) reacted with tosyl chloride, pyridine, and benzoyl chloride to give mesoionic compound (11) having 3-benzoyl and 5-(p-tolylthio) groups.
Proton NMR Spectra and Conformations of N-Alkyl-N-benzyl-and N-Alkyl-N-(α-chlorobenzyl)carbamoyl Chlorides
Authors: Koyano Kinko , Suzuki Hiroshi , McArthur Colin R 
Published: July 2006

Abstract
Rotational isomerization about the amide C–N bond of twelve N-alkyl-N-benzylcarbamoyl chlorides (C6H5CHX–NR–COCl, 1: X=H, 2: X=Cl; R=CH3, C2H5, n- and i-C3H7, n- and t-C4H9) was studied by proton NMR spectroscopy. The values of ΔG\eweq for the isomerization are 15.8–17.3 kcal/mol for compounds 1 and 13.3–15.9 kcal/mol for compounds 2. Another kind of slow rotation was observed about the benzyl–nitrogen bond of 1(R=t-C4H9) and the α-chlorobenzyl–nitrogen bond of 2(R=CH3) at low temperature. The chiral centers of compounds 2 produce large nonequivalences for the geminal protons of the 2-methylene group of 2(R=n-C3H7) as well as 2(R=n-C4H9) and for the geminal methyl protons of 2(R=i-C3H7), reflecting some conformational preference of these compounds.
The σ-Bonded Palladium(II) Complex of 2-Pyridylferrocene
Authors: Kasahara Akira , Izumi Taeko , Maemura Mitsugi 
Published: July 2006

Abstract
2-Pyridylferrocene reacts with lithium tetrachloropalladate(II) in the presence of sodium acetate to give an ortho-palladated binuclear complex (4). The σ-bonded structure of 4 was confirmed by studies of the IR and NMR spectra and of the reactions of 4 with thallium (I) acetylacetonate and lithium aluminum deuteride. The reactions of 4 with carbon monoxide, butyllithium, and bromine were also examined.
The Titanium Trichloride-catalyzed Oxidation of Triphenylphosphine with Oxygen in Acetonitrile
Authors: Chimura Yasuo , Tarama Kimio 
Published: July 2006

Abstract
Titanium trichloride catalyzed very rapidly the oxidation of triphenylphosphine with oxygen in acetonitrile, yielding triphenylphosphine oxide and a yellow precipitate. The main catalytic cycle did not contain Cl3Ti–O–TiCl3 which was produced in the oxidation of TiCl3 alone, but the precursors of Cl3Ti–O–TiCl3 as intermediates. The yellow precipitate was a titanium(IV) complex with a discrete TiO group.
Polarographic Catalytic Currents Observed in Mixtures of Pb(II) and H2O2 in Neutral Solutions
Authors: Himeno Sadayuki 
Published: July 2006

Abstract
Normal pulse polarography has shown that the catalytic wave observed in neutral mixtures of Pb(II) and H2O2 is caused by Pb(OH)+ at the electrode surface, and that OH− ions are liberated in the vicinity of the electrode due to the catalytic reaction.