bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tris(tellurato)cobaltate(III) and Tris(ethylenediamine)tris(tellurato)tetracobaltate(III) Complexes
Authors: Shimura Yoichi , Hosokawa Yutaka 
Published: July 2006

Abstract
Alkali metal salts of two new telluratocobaltate(III) complexes, [Co(TeO6H4)3]3− and [Co4Te3O18(en)3]6−, have been prepared. The latter heteropoly type complex and the related periodate analogue [Co4I3O18(en)3]3− have been optically resolved.
Diode Laser Spectrum of the ν8 Band of CH3SH
Authors: Nakagawa Kuniaki , Kojima Takeshi , Hirota Eizi 
Published: July 2006

Abstract
The Stark effect was used to assign four series of the transitions in the heavily perturbed spectrum of methanethiol in the 14 μm region: K=0 and two K=1 series of A torsional symmetry and K=0 series of E symmetry. Effective parameters were determined for each series. The K=0 levels of A symmetry in the ν8 state were found to be perturbed by a Fermi-type resonance.
ESR Study of Glass-Like Carbons
Authors: Kawamura Kazuro , Kimura Shiushichi 
Published: July 2006

Abstract
ESR studies were carried out on a variety of glass-like carbons made from different precursors heat-treated in the range 300–2500 °C. It was found that the behaviors of unpaired electrons were nearly identical. The temperature dependence of ESR spectrum showed that the behavior of localized unpaired electrons in the glass-like carbons changed to that of delocalized ones at HTT about 2500 °C. The ESR spectrum of the glass-like carbons heat-treated at 800 °C consisted of a single line under a pressure of above 10−4 Torr but split into two components when air was admitted. This strong interaction with unpaired electrons and air (oxygen molecules) is caused by the active structure related to micropores in the glass-like carbons. We suppose that the polyene type radicals are the most suitable as the active structure to interpret the behavior of unpaired electrons in glass-like carbons heat-treated at 800 °C. As another major point in this study, it was found that there is a correlation between unpaired electron concentration and the g value.
Solid-State NMR Studies on Pillar-Interlayered Naturally-Occurring Montmorillonite
Authors: Matsumoto Mutsuyoshi , Suzuki Minoru , Takahashi Hiroshi , Saito Yasukazu 
Published: July 2006

Abstract
Solid-state MAS NMR spectroscopy on naturally occurring montmorillonite has revealed that the Fe(III), contained in the octahedral layer, exerts a greater influence on octahedral Al nuclei than on tetrahedral ones. The same trend is observed in a more pronounced manner with the material intercalated with [AlO4Al12(OH)24(OH2)12]7+ cations. Mechanisms of selective peak broadening in solidstate NMR spectra are discussed.
Metal Complexes of Amino Acids. XV. Racemization and Deuteration of Bis(biguanide)sarcosinatocobalt(III) Complex
Authors: Kawaguchi Hiroshi , Matsuki Mizuki , Ama Tomoharu , Yasui Takaji 
Published: July 2006

Abstract
All four possible optical isomers (Δ(S), Δ(R), Λ(S), and Λ(R)) of the bis(biguanide)sarcosinatocobalt(III) ion, [Co(sar)(Hbg)2]2+, were isolated and characterized by their absorption, CD, and 1H NMR spectra. The optically active [Co(sar)(Hbg)2]2+ ion in a basic aqueous solution showed a loss of CD intensity due to racemizations at both the chiral cobalt center (Δ\ightleftarrowsΛ) and the asymmetric nitrogen center (R\ightleftarrowsS). The rate of an R\ightleftarrowsS change was ca. 50 times slower than that of a Δ\ightleftarrowsΛ change. The rate of deuteration (H→D) at the asymmetric nitrogen atom was slower than those of other sarcosinato complexes. The ratio kH–D/kinv was about 102–103. The rates of racemization (Δ\ightleftarrowsΛ) for the [Co(amino acidato)(Hbg)2]2+ ion series increased in the order l-valine&lt;l-alanine&lt;glycine&lt;sarcosine.
X-Ray Structure of 5-Chloro-1-thia-5-boracyclooctane
Authors: Furusaki Akio , Weike Zhou , Suzuki Akira 
Published: July 2006

Abstract
5-Chloro-1-thia-5-boracyclooctane has been prepared by the hydroboration of diallyl sulfide with a chloroborane–dimethyl sulfide complex and its structure containing a sulfur–boron dative bond has been examined in detail by an X-ray crystallographic analysis.
Reaction of α,β-Unsaturated Carboxylic Acids with Manganese(III) Acetate in the Presence of Chloride Ion
Authors: Yonemura Hiroshi , Nishino Hiroshi , Kurosawa Kazu 
Published: July 2006

Abstract
The reaction of 3-phenylpropenoic acids with manganese(III) acetate–Cl− complex yielded 1,2,2-trichloro-1-phenylethanes, 1-acetoxy-2,2-dichloro-1-phenylethanes, and 2,2-dichloro-1-phenylethanols. (E)-2,3-Diphenylpropenoic acids gave 2,2-dichloro-1,2-diphenylethanones and 2-acetoxy-1,2-diphenylethanones. 3,3-Diphenylpropenoic acids yielded 2,2-dichloro-1,1-diphenylethenes, 1-acetoxy-2,2-dichloro-1,1-diphenylethanes, 2,2-dichloro-1,1-diphenyl-1-ethanols, and 2-hydroxy-2,2-diphenylethanal. Fluorenylideneacetic acid gave 9-chloro-9-(dichloromethyl)fluorene, 9-acetoxy-9-(dichloromethyl)fluorene, and 9-fluorenone. 1-Cyclohexenecarboxylic acid yielded 1,2-dichlorocyclohexanecarboxylic acid and 1-acetoxy-2-chlorocyclohexanecarboxylic acid. The reaction can be explained in terms of a free-radical mechanism involving manganese(III) acetate–Cl− complexation, addition of Cl− radical, decarboxylation, and the oxidation of chloroethenes which are the reaction intermediates.
A Positive Halogen Mediated Ring-Opening Reaction of 2-(α-Phenylthiobenzyl)cycloalkanol Derivatives
Authors: Yasumura Masateru , Takaki Ken , Tamura Takao , Negoro Kenji 
Published: July 2006

Abstract
A new ring-opening reaction of the title cycloalkanols (1 and 3) takes place upon treatment with N-chloro-succinimide and triethylamine to give ω-oxo α,β-unsaturated sulfides (2) in fairly good yields.
Thermal Dimerization of 10-Methyleneanthrone
Authors: Hirakawa Kiyoichi , Ogiue Eriko , Motoyoshiya Jiro , Kakurai Toshio 
Published: July 2006

Abstract
The thermal reaction of the title compound (1) gave three dimeric products which were formed via a path involving two competitive reactions, Diels-Alder and radical dimerization.
Solvent Extraction Separation of Germanium with Aliquat 336S from Citric Acid Solutions
Authors: Vibhute Chandrashekhar P , Khopkar Shripad M 
Published: July 2006

Abstract
Germanium was quantitatively extracted with 0.1 mol dm−3 Aliquat 336S in xylene from 1×10−3 mol dm−3 citric acid solution adjusted to pH 3.5. It was stripped with 0.5 mol dm−3 hydrochloric acid and determined spectrophotometrically at 530 nm as the complex with phenylfluorone. It was effectively separated from binary as well as ternary mixtures by taking advantage of the difference in the stability of the citrate complexes with metal ions in mineral acids. The method was applied to the determination of germanium in coal fly ash.
Removal of Some Alkali Salts from Aqueous Solution by Active-Charcoal Electrode
Authors: Ichinose Masao , Yasuoka Takashi , Mitsuzawa Shunmei , Sasaki Tsunetaka 
Published: July 2006

Abstract
An electrolytic removal of potassium and sodium sulfates from aqueous solutions was worked out by using an active-charcoal cathode and a platinum anode with a porous porcelain septum between them. Maximum removal of nearly 99% was attained for these salts. The mechanism of removal was confirmed to be based on the facts that potassium and sodium ions are entrapped and concentrated as hydroxides in the pores of the active-charcoal cathode while sulfate ions are removed from the solution and concentrated as sulfuric acid in the anode chamber.
Theoretical Studies on the Catalytic Oxidation of Carbon Monoxide on Nickel Clusters
Authors: Srivastava A K , Kojima Isao , Miyazaki Eizo 
Published: July 2006

Abstract
Complete neglect of differential overlap (CNDO) molecular orbital calculations using the method of Anno and Sakai for the evaluation of the valence orbital ionization potential (VOIP) were performed with the aim of studying the oxidation of carbon monoxide on nickel clusters. A cluster surface was assumed to be preadsorbed with oxygen and the variation of various bond energies with the approach of a carbon monoxide molecule was studied for different models. Various possibilities for the reaction path are discussed in the light of the theoretical findings and it is suggested that at a low coverage of oxygen the reaction may follow a Langmuir–Hinshelwood path, whereas at a high coverage, an Eley–Rideal path might be more probable.
Reaction of Tri-n-butyltin ω-Haloalkoxide (n-Bu3SnO(CH2)nX) with Isothiocyanate
Authors: Baba Akio , Shibata Ikuya , Kashiwagi Hiroki , Matsuda Haruo 
Published: July 2006

Abstract
Tri-n-butyltin ω-haloalkoxides are useful reagents for the preparation of sulfur-containing five and six-membered cyclic compounds combined with isothiocyanates.
Pretreatments of Porous Silica for Improving the Activity of a Nickel-Loaded Catalyst
Authors: Arai Masahiko , Ikushima Yutaka , Nishiyama Yoshiyuki 
Published: July 2006

Abstract
Nickel catalysts supported on porous silicas treated with water, ethanol, and 1-butanol were found to be more active than that supported on untreated silica for ethane hydrogenolysis and furan hydrogenation. To elucidate the reason for the activation, some surface properties of the treated silicas were examined. The treatments decreased the surface area and increased the volume of the macropores, the surface density of hydroxyl groups, and the heat of immersion in water per unit surface area. The state of nickel on the support was examined by temperature programed desorption(TPD) of hydrogen, X-ray diffraction(XRD), and scanning electron microscopy/X-ray microanalysis. The dispersion measured by XRD was not appreciably altered by the treatments, but the TPD snowed more hydrogen desorbed above 150 °C from nickel on the treated supports. The activation of nickel by pretreatment of the support was ascribed to the increase of those nickel atoms which dispersed finely over the support by the increased number of surface hydroxyl groups. This was based on the number of hydroxyl groups per unit surface area. The nickel catalyst supported on the pretreated silicas showed greater thermal stability.
Dynamic NMR as a Nondestructive Method for the Determination of Rates of Dissociation. X. Rates of Dissociation of the C–N Bond in Substituted 1-(1,3-Dithiolan-2-yl)pyridinium Perchlorates
Authors: Morita Toshiari , Oki Michinori 
Published: July 2006

Abstract
Rates of dissociation of the C–N bond in substituted 1-(1,3-dithiolan-2-yl)pyridinium ions in the perchlorate forms were obtained by the dynamic NMR technique in nitromethane-d3 and for one case in acetonitrile-d3. The study of the substituent effects on the rates of dissociation revealed that the rates were linearly correlated with the pKa values of the substituted pyridines. The mechanism of the dissociation was postulated to be of SN2 type, the perchlorate ion acting as a nucleophile, from the kinetic data.
Stereoselective Cycloadditions of Pyridinium or Isoquinolinium Methylides with Olefinic Dipolarophiles and Subsequent Cycloadditions of the Cycloadducts with Nitrile Oxides
Authors: Tsuge Otohiko , Kanemasa Shuji , Takenaka Shigeori 
Published: July 2006

Abstract
Pyridinium or isoquinolinium methylides undergo highly stereo- and regioselective cycloadditions with olefinic dipolarophiles to form unstable tetrahydroindolizine derivatives. One of the two double bonds existing in the dihydro heteroaromatic ring of the cycloadducts reacts with nitrile oxides, in the same flask, in stereo-, regio-, and periselective fashions to lead to stable isoxazole-fused tetrahydroindolizines in good yields.
Nonexistence of Hydration Number Change of Cd2+ Ions in Aqueous Cd(NO3)2 Solution
Authors: Kanno Hitoshi 
Published: July 2006

Abstract
Raman spectra for the Cd2+–OH2 stretching vibration (ν1 band) were measured for aqueous Cd(NO3)2 solutions of R=15 and 40 (R: moles of water/moles of salt). Contrary to the results reported by Kuznetsov et al., it is concluded that the hydration number of Cd2+ ions does not change with salt concentration in the Cd(NO3)2 solution.
Solvent Effects on the Unimolecular Dissociation of Radical Anions Studied by Pulse Radiolysis
Authors: Kimura Norio , Takamuku Setsuo 
Published: July 2006

Abstract
The rate constants of the unimolecular dissociation of radical anions formed by one-electron reduction of chloroacetophenone isomers in dipolar aprotic solvents were measured by a pulse radiolysis technique. The reactivities of these isomers were affected by the polarity of the solvent used.
Stabilities of the Copper(II) Complexes with Quadridentate Derivatives of l-Prolinamide and l-Proline Methylamide
Authors: Murakami Tasuku , Chiba Koichi 
Published: July 2006

Abstract
The stability constants of the copper(II) complexes with potentially quadridentate derivatives of l-prolinamide and l-proline methylamide (see text) have been determined by potentiometric titrations. The amide-proton dissociations from the complexes have also been estimated. These were then discussed in terms of the ligand structure and the complex geometry.
Temperature-Programmed Desorption of Ammonia on Zeolites. Influence of the Experimental Conditions on the Acidity Measurement
Authors: Niwa Miki , Iwamoto Masakazu , Segawa Koh-ichi 
Published: July 2006

Abstract
The Influence of the experimental conditions of the TPD (Temperature-Programmed Desorption) of ammonia on the measurement of acidity of mordenites and Y zeolites was studied. The results were applicable to the measurements of the strength and the number of acid sites of zeolites. For contact times of the carrier gas from 10−2 to 10−6 g min ml−1 defined as W/F (W, sample weight; F, flow rate of the carrier gas), the peak maximum temperature was related to the parameter (W/F). The relationship was explained on the basis of a theoretical equation derived by Cvetanovic and Amenomiya under the conditions of readsorption. Ammonia is readsorbed on zeolites under these conditions, and one has to use the experimental conditions of the same contact time in order to evaluate the acid strength of zeolite from the peak maximum temperature. On the other hand, the ratio of intensity of low temperature peak (1-peak) to that of the high temperature peak (h-peak) increased with increasing the contact time of the carrier gas. This relation suggested that the 1-peak intensity depended upon the degree of evacuation of the weakly-held ammonia. The 1-peak is ascribable to very weakly or physically adsorbed ammonia on zeolites, and only the h-peak has to be accounted for to measure the number of acid sites.
The Solvent Extraction of Alkaline Earth Metal Ions with Nonionic Surfactants
Authors: Sakai Yukio , Nakamura Hiroshi , Takagi Makoto , Ueno Keihei 
Published: July 2006

Abstract
The extraction of alkaline earth metal ions has been investigated using a mixture of polyethylene glycol mono-p-nonylphenyl ether (PEGP; average number of oxyethylene group, 10) and 4-(1,1-dimethyl-3,3-dimethylbutyl)-2,5-dinitrophenol (2,5-dinitro-4-t-octylphenol, DNP; HL) in 1,2-dichloroethane. The metal extraction takes place with one molecule of deprotonated DNP (L−) and an extraneous monoanion (X−) for neutralization of the dicationic charge of the metal ion. The ease of extraction generally follows the order, Ba2+&gt;Sr2+&gt;Ca2+&gt;&gt;Mg2+. The nature of the anion present in the aqueous phase strongly affects the extractability. For barium, the extractability decreases in the order ClO4−&gt;SCN−&gt;I−&gt;Cl−&gt;NO3−. The composition of the extracted complexes for barium and strontium ions proportional to the metal is metal : PEGP : L− : X−=1 : 1 : 1 : 1. The overall extraction constants were estimated.
Solvent Extraction of Copper(II) with Lipoic Acid in Benzene. Evidence for the Preferential Coordination of Carboxylate
Authors: Yamada Hiromichi , Okuda Toshiyuki , Fujii Yukio , Mizuta Masateru , Tanaka Motoharu 
Published: July 2006

Abstract
The extraction of copper(II) was carried out with lipoic acid in benzene at 25 °C and at a constant ionic strength in the aqueous phase: 0.1 mol dm−3 (NaNO3). The partition constant, KD,HA of lipoic acid between benzene and water, and the dimerization constant, K2,HA of lipoic acid in benzene were determined: logKD,HA=1.17 and logK2,HA=2.51 The dimeric copper(II) lipoate is responsible for the extraction:
2Cu2++3(HA)2,o\oversetKex(22)\ightleftharpoons(Cu2A4(HA)2)o+4H+
with the extraction constant, logKex(22)=−11.00. It was proved that lipoate ion coordinates to copper(II) with the carboxylate group without a remarkable participation of the disulfide moiety in the coordination.
Liquid Crystal Materials with Sulfur Atoms Incorporated in the Principal Structure. VI. Optically Active New Smectic Liquid Crystal Compounds with 1,3-Oxathiane or 1,3-Dithiane Ring
Authors: Haramoto Yuichiro , Tomita Yoko , Kamogawa Hiroyoshi 
Published: July 2006

Abstract
(+)-2-Methylbutyl p-(5-alkyl-1,3-oxathian-2-yl)benzoate and -cinnamate (7) were synthesized. The mesomorphic behavior of these compounds were measured. Though (+)-2-methylbutyl p-(5-alkyl-1,3-oxathian-2-yl)benzoate did not exhibit any liquid-crystal phase, the corresponding 1,3-dithiane compounds (8-1, 8-2, and 8-3) and compound (7-4) having R’ of a normal alkyl chain exhibited a smectic phase. This must originate in the wider molecular widths of compounds 7-1, 7-2, and 7-3. Though cinnamate of compounds 7 and 8 exhibited an enantiotropic behavior, the corresponding benzoate did not. This must originate from an increase in the length of the conjugated system and the molecular length.
Visible Light- and Radiation-Induced Alkylation of Pyridine Ring with Alkanoic Acid. Effective Alkylation in the Presence of Iron(III) Sulfate
Authors: Sugimori Akira , Yamada Tetsuo 
Published: July 2006

Abstract
Quinoline and 4-methylquinoline are efficiently alkylated with alkanoic acid in the presence of iron(III) sulfate upon visible light-irradiation. Iron(III) sulfate not only accelerates the photoreaction but also increases the yield of alkylation. Gamma-irradiation also brings about the alkylation. In the photo- and radiation-induced alkylation with alkanoic acid, alkyl radicals play important roles.
A Study on the Mechanism of the Dimerization of Quinazoline Compounds Catalyzed by Cyanide Ions
Authors: Goto Ayako , Higashino Takeo 
Published: July 2006

Abstract
It was shown that an intermediate, 4,4′(3H,3′H)-biquinazolinylidene (2a) was isolated in the formation process of 4,4′-biquinazolinyl (3a) which was obtained from the reaction of quinazoline (1a) with potassium cyanide, and 2a was readily oxidized to 3a by oxygen in air. The dimerization process was studied kinetically by NMR method. The result showed that the process was essentially similar to that of the benzoin condensation. The introduction of a methyl group into the C2-position of 1a resulted in a lowering of the reaction rate because the activation energy of 2-methylquinazoline (1b) dimerization became higher compared with that of 1a dimerization.
An Improved Method for Stereoselective Synthesis of (E)-Alkenes via Alkenyldialkylboranes
Authors: Hoshi Masayuki , Masuda Yuzuru , Arase Akira 
Published: July 2006

Abstract
Successive treatments of alkenyldialkylboranes, formed by the reaction of alkynes and sterically hindered dialkylboranes, with alkyllithium and benzenesulfenyl chloride afforded highly pure (E)-alkenes in good or excellent yields.
Control of Product in the Reaction of Tributyltin ω-Haloalkoxide (n-Bu3SnO(CH2)nX) with Diphenylketene
Authors: Shibata Ikuya , Baba Akio , Matsuda Haruo 
Published: July 2006

Abstract
The reaction of tributyltin ω-haloalkoxide with diphenylketene gave cyclic ketene acetals and/or lactones, and the ratio of these products were controled by the number of methylene groups and by the addition of Lewis base in the reaction system. Moreover, the direct cycloaddition of diphenylketene with cyclic ethers proceeded in high yields, catalyzed by organotin halide–Lewis base complexes.
Synthesis and Biological Activities of d-Homoglutamine Analogs of Substance P
Authors: Hashimoto Tadashi , Uchida Yoshiki , Nishijima Miwako , Moro Tadashi , Sakura Naoki , Hirose Kyoko 
Published: July 2006

Abstract
Six substance P (SP) analogs substituted by d-homoglutamine (Hgn) at position 5 or/and 6 were prepared by the solid phase method. The activity of the peptides was assayed on the smooth muscles of the isolated guinea pig ileum and trachea. Results indicate that the substitution of d-Hgn for Gin residue(s) reduces the activity. [d-Hgn6]-SP (4–11) 5 acted as an antagonist of SP.
Novel Glycosidation of 4-Demethoxyanthracyclinones by the Use of Trimethylsilyl Triflate. Syntheses of Optically Active 4-Demethoxydaunorubicin and 4-Demethoxyadriamycin
Authors: Kimura Yoshikazu , Suzuki Michiyo , Matsumoto Teruyo , Abe Rumiko , Terashima Shiro 
Published: July 2006

Abstract
Optically pure (+)-4-demethoxydaunorubicin has been prepared by a novel glycosidation reaction of (+)-4-demethoxydaunomycinone with (−)-3-N-trifluoroacetyl-1,4-bis(O-p-nitrobenzoyl)-l-daunosamine in the presence of trimethylsilyl triflate, followed by sequential O- and N-deprotection reactions. Total synthesis of optically pure (+)-4-demethoxyadriamycin has been also accomplished by two different synthetic schemes, starting from (+)-4-demethoxydaunorubicin or by way of (+)-3′-N-trifluoroacetyl-4-demethoxyadriamycin. (+)-4-Demethoxyadriamycin prepared by our hands was fully characterized by its spectral properties.
Absolute Configuration and Circular Dichroism Spectrum of all-cis(NO2,N,O)-(−)450CD[Co(NO2)2(gly)2]− Complex
Authors: Fujinami Shuhei , Miyamae Hiroshi , Miura Takahiro , Fushimi Koichi 
Published: July 2006

Abstract
An X-Ray analysis of all-cis(NO2,N,O)-(−)450CDK[Co(NO2)2(gly)2]·1/2H2O has been carried out. The crystal form is trigonal, P3121, with a=10.747(1), c=18.589(4) Å and Z=6. The structure was refined by a block-diagonal least-squares method to a final R value of 0.047 for 3207 independent reflections with |Fo|&gt;3σ(|Fo|). The absolute configuration of the (−)450CD[Co(NO2)2(gly)2]− ion has been determined to be Δ(R). By comparing the CD spectrum of Δ(R)-[Co(NO2)2(gly)2]− with that of a related Λ(R)-[Co(NO2)2(en)(ox)]− complex, the optical activities of these complexes have been concluded to be derived largely from helical distributions of chelate rings.
Synthesis of Sydnone Compounds Substituted by Heteroatom Groups at the 4-Positions
Authors: Fuchigami Toshio , Chen Ching-Sy , Nonaka Tsutomu , Yeh Mou-Yung , Tien Hsien-Ju 
Published: July 2006

Abstract
A general method for the introduction of heteroatoms to the 4-position of a sydnone ring was developed. Various 4-alkylthio- and 4-arylthiosydnones were prepared in excellent yields by the reaction of 3-aryl-4-lithiosydnones (2) with dialkyl and diaryl disulfides. Treatment of 2 with diaryl diselenides, diphenylphosphinous chloride, and arsenic trichloride provided 3-aryl-4-(arylseleno)sydnones, (3-aryl-4-sydnonyl)diphenylphosphine and tris(3-aryl-4-sydnonyl)arsine, respectively, in good yields. It was also found that the reactivity of sydnonyl anions derived from 2 was quite different in some cases from that of the corresponding ordinary aromatic analogues, though the sydnone ring has a somewhat aromatic nature.
Efficient Synthesis of a New Amino Acid, (2S,3R,4R)-4-Chloro-3-hydroxyproline
Authors: Lee Sannamu , Kodera Yasushi , Noda Kosaku , Aoyagi Haruhiko , Kato Tetsuo , Izumiya Nobuo 
Published: July 2006

Abstract
An unusual new amino acid, (2S,3R,4R)-4-chloro-3-hydroxyproline, was stereospecifically synthesized through a four-intermediate from Boc-3,4-dehydro-l-proline. The obtained product was stable in a mild alkaline solution.