bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of the Anion on the Extraction of Cobalt with 8-Quinolinol into Chloroform
Authors: Sekido Eiichi , Fujita Kazuhiko 
Published: July 2006

Abstract
The effects of the anions, especially the perchlorate ion, on the extraction of cobalt into chloroform with 8-quinolinol (Hql) were examined. Two kinds of cobalt(II) 8-quinolinol complexes, species A and B, are extracted into the chloroform phase from the aqueous cobalt(II) solution containing perchlorate ions. Species A contains no perchlorate ion and is extracted above pH 7.7; species B is an ion-pair complex containing a perchlorate ion and is predominantly extracted below pH 5.1. The compositions of species A and B were estimated to be Co2ql4(Hql)2 and Co2ql3(Hql)3ClO4, respectively. These dimer complexes are related by the following equilibrium, with logKAB=−7.2:
[Co_2ql_3(Hql)_3]^+ClO_4(o)^-\ightleftarrowsCo_2ql_4(Hql)_2(o)+ClO_4^-+H^+
The species extracted into the chloroform phase from the aqueous cobalt(II) solution containing sulfate ions does not contain any sulfate ions. The formation of the species containing anions increases in the order: ClO4−&gt;NO3−&gt;Cl−&gt;So42−, which is also the general order of the extent of forming the ion-pair compounds. The ion-pair complex tends to prevent the oxidation from cobalt(II) 8-quinolinol complex to cobalt(III) 8-quinolinol complex.
Keto-Enol Tautomerism. I. The Calorimetrical Determination of the Equilibrium Constant for Keto-Enol Tautomerism for Cyclopentanone
Authors: Hine Jack , Arata Kazushi 
Published: July 2006

Abstract
The enol content of cyclopentanone was determined by calorimetrical measurement of the enthalpy of hydrolysis of cyclopentenyl methyl ether to cyclopentanone with the assumption that the thermodynamics of hydrolysis of any ROMe to ROH is the same as that for any other ROMe. The enthalpy of the ketonization of cyclopentenol was determined to be −7.87 kcal/mol in the liquid phase and −11.66 kcal/mol in the gas phase, at 25 °C. The enol content of cyclopentanone in the gas phase at 25 °C was found to be 2.5×10−7%
Keto-Enol Tautomerism. II. The Calorimetrical Determination of the Equilibrium Constants for Keto-Enol Tautomerism for Cyclohexanone and Acetone
Authors: Hine Jack , Arata Kazushi 
Published: July 2006

Abstract
The vapor phase enol contents of cyclohexanone and acetone were determined by calorimetric measurements of the enthalpies of hydrolysis of their corresponding enol methyl ethers to ketones and methanol in 91.67% THF–H2O (0.15 M H2SO4). The relative order of enol content, together with cyclopentanone in our previous study, was cyclohexanone&gt;cyclopentanone≥ acetone, which was the same as that reported by Gero and by Schwarzenbach, but different from Bell’s observed order (cyclopentanone&gt;cyclohexanone&gt;acetone). The enthalpies calculated from Benson’s correlation of thermodynamic properties for the enolization reactions of these ketones and for the hydrolysis reactions of enol methyl ethers agreed with our relative ordering. Furthermore, data on reactions of compounds with 5- and 6-membered rings lead to the prediction that cyclohexanone contains more enol than cyclopentanone does. The kinetics of hydrolysis of enol methyl ethers was also discussed.
The Thermal Decomposition of N-Thiocarbonyl Diphenylsulfimides
Authors: Yoshida Hiroshi , Taketani Hitoshi , Ogata Tsuyoshi , Inokawa Saburo 
Published: July 2006

Abstract
N-Thiocarbonyl diphenylsulfimides, Ia–i (R=Ph, p- and m-MeC6H4, p- and m-MeOC6H4, MeO, EtO, MeNH, and Me2N), were prepared, and their thermal decomposition were studied. At 70 °C, Ia–h decomposed easily to give nitriles (or their derivatives), together with diphenyl sulfide and sulfur. Contrary to these results, the oxygen analog of Ia, g showed no decomposition even upon heating at 140 °C. The thermolysis of Ia–e in the presence of excess acetylenes (III) gave isothiazoles(IV) in moderate yields. Thiazirine(V) and nitrile sulfide(VI) may be supposed, on the basis of the kinetic experiments, to be possible intermediates for the thermal decomposition of Ib–e.
Biogenetic Model Reactions of Epoxygermacrones
Authors: Niwa Masatake , Iguchi Masanobu , Yamamura Shosuke 
Published: July 2006

Abstract
From a biogenetic point of view, acid- or base-catalyzed cyclizations of epoxygermacrones (2, 23, and 33) were carried out. In most cases, the stereospecific cyclizations of these epoxygermacrones took place to give many compounds with an 11-oxabicyclo[5.3.1]undecane system, cadinane-type, selinane-type or guaiane-type compounds depending on the kinds of reagents and solvents. The formation process of each cyclization product will be discussed in detail.
Regio- and Stereospecific Cyclizations of Germacrones
Authors: Niwa Masatake , Iguchi Masanobu , Yamamura Shosuke 
Published: July 2006

Abstract
From a biogenetic point of view, the acid-catalyzed cyclizations of germacrones (1, 2, and 3) were carried out, using several kinds of reagents and solvents (80% aq AcOH, 80% aq HCOOH, AlCl3 in absolute ether, AcOH in PhSH, 100% HCOOH in PhSH, and concd H2SO4 in PhSH). In all cases, the stereospecific cyclizations of these germacrones took place to give cadinane-type, selinane-type or guaiane-type compounds depending on the kinds of reagents and solvents. The formation process of each compound will be presented in detail.
A Single-step Synthesis of 2-Substituted 2-Thiazolines
Authors: Suzuki Nobutaka , Izawa Yasuji 
Published: July 2006

Abstract
2-Phenyl-2-thiazoline (4b) and its derivatives: [4-carboxylic acid (4c), 4-carboxylic acid methyl ester (4d), and 5,5-dimethyl-4-carboxylic acid (4e)], 2-(p-chlorophenyl)-2-thiazoline (4f) and its 4-carboxylic acid (4g), and 2-methyl-2-thiazoline (4h) were obtained by treating RCS2CH2CO2H [R=Phenyl (1b), p-chlorophenyl (Id), or methyl (1e)] or MeCS2Et (1f) with the corresponding 2-aminoethane thiols, i.e., cysteamine (6a), cysteine (6b), cysteine methy ester (6c), and/or penicillamine (6d). 4b was also obtained from PhCS2Et (1c) and 6a with a rate approximately equal to that from 1b and 6a. The attempted synthesis of 2-methyl-2-thiazoline-4-carboxylic acid (4i) using a similar method gave only N-acetylcysteine (7).
The Wolff Rearrangement and 1,3-Dipolar Cycloaddition of 2-Diazo-3,4-bis(diphenylmethylene)cyclobutanone
Authors: Ueda Kozaburo , Igaki Masanori , Toda Fumio 
Published: July 2006

Abstract
The first example of the Wolff rearrangement of α-diazocyclobutanone, the title diazo ketone (2), into the three-membered cyclic ketene (4) was observed. The ketene intermediate (4) could be trapped by its reaction with alcohols, aniline, azobenzene, and N-benzylideneaniline to afford 1-alkoxycarbonyl- (5a–c) and 1-phenylcarbamoyl-2,3-bis(diphenylmethylene)cyclopropane (5e), and 1,2-bis(diphenylmethylene)-5,6-diphenyl-5,6-diaza-(9) and 1,2-bis(diphenylmethylene)-5,6-diphenyl-5-azaspiro[2,3]hexan-4-one (10a), respectively. In contrast to the rearrangement, 2 directly reacted with p-benzoquinone and nitrosobenzene, affording the corresponding 1,3-dipolar cycloadducts (14 and 15).
The Lanthanoid-Induced Shifts of Proton NMR Spectra and the Conformations of β-(2-Thienyl)acrylic Esters and Related Compounds
Authors: Hirota Minoru , Yoshida Shigeko , Nagawa Yoshinobu , Ono Makoto , Endo Hiroko , Satonaka Hajime 
Published: July 2006

Abstract
The most predominant conformation of 4-(2-thienyl)-3-butene-2-one and methyl β-(2-thienyl)acrylates were determined by the analysis of their LIS’s. The LIS’s toward higher fields were observed with some ring protons (H3’s and some of H4’s), and were best interpreted by assuming that about 20% of the shift reagent coordinates on the methoxyl oxygen atom and the rest on the carbonyl oxygen atom.
Layered Compounds. XXXVI. Structure and Properties of Triple-layered Metaparacyclophanes
Authors: Kannen Naoki , Otsubo Tetsuo , Sakata Yoshiteru , Misumi Soichi 
Published: July 2006

Abstract
The geometrical structures of triple-layered metaparacyclophanes are discussed on the basis of the chemical shifts of the NMR spectra and their temperature dependence. [2.2]Metacyclo(4,7)[2.2]paracyclophane 1 and [2.2]metacyclo(12,15)[2.2]metaparacyclophane 2 proved to be mixtures of conformational isomers due to arrangement of meta-substituted ring. [2.2]Paracyclo(4,6)[2.2]metaparacyclophane 3 was confirmed to be a staircase-shape (anti-form), in contrast to a platform-shape (syn-form) of [2.2]metacyclo(4,6)[2.2]metaparacyclophane 5. In their electronic spectra, 1 and 2 exhibit a transannular electronic interaction between the benzene rings similar to that of multilayered [2.2]paracyclophanes; 3 and 5 show one similar to that of multilayered [2.2]metacyclo-phanes. The difference between the former and the latter groups seems to arise from the substitution modes of methylene bridges attached to the inside benzene of triple-layered metaparacyclophanes.
Layered Compounds. XXXV. Syntheses of Triple-layered Metaparacyclophanes
Authors: Kannen Naoki , Otsubo Tetsuo , Sakata Yoshiteru , Misumi Soichi 
Published: July 2006

Abstract
Six triple-layered [2.2]metaparacyclophanes have been prepared using general synthetic methods such as the Stevens rearrangement-Raney nickel desulfurization method, pyrolysis of bissulfone, and photo-induced desulfurization. The pyrolysis of bissulfone has turned out to be the most useful and convenient method for preparation of the intermediate double-layered [2.2]metaparacyclophanes because of simple experimental process and excellent yields. The unexpected formation of compound 9 during the photo-induced desulfurization of 7 was explained by a unique skeletal rearrangement of the intermediate 8 on irradiation.
The Alkoxylation of Aerosil Silica with C1–C4 Alcohols
Authors: Kitahara Shigeto 
Published: July 2006

Abstract
The Aerosil surface was treated with C1–C4 alcohols under both high-pressure and low-pressure conditions. The high-pressure treatment was carried out at various temperatures up to 250 °C using an autoclave, while the low-pressure treatment was done at 280 °C under vapor pressure at room temperature. The surface changes were followed by IR spectroscopy, and the carbon content was determined. The degrees of alkoxylation (OR groups/100 Å2) of the Aerosils treated sufficiently under low pressures were 1.3–1.6, approximately equal to the amount of OH isolated before the treatment, while the values under high pressures reached 2.3–3.4, equal or near to the amount of the total OH. The values for methoxylation were particularly higher, while those for t-butoxylation were quite low. These results, in addition to the observation of the IR spectra, indicate that the isolated OH groups are predominantly esterified under low pressures, while under high pressures the vicinal OH groups are esterified as well, and the opening of the siloxane bonds occurs easily in the case of methoxylation. The stability of the alkyl groups on the Aerosil against heating decreased in the order of: primary&gt;secondary&gt;tertiary.
Spectroscopic Study of Alkyl Vinyl Ketones
Authors: Naito Ikuo , Kinoshita Akihiro , Yonemitsu Tadashi 
Published: July 2006

Abstract
Alkyl vinyl ketones have two conformations, s-cis and s-trans. The ratios of the two conformers are given by comparing their IR with NMR data. The conformer of s-cis is given by the equation, Percentage of s-cis=180. (Δδ−0.15) (%), where Δδ is the chemical shift difference between cis and trans protons for carbonyl group. The value of ΔF obtained by means of the equation is related to steric factors Esc of bearing alkyl groups. The ratio s-cis/s-trans is determined by the bulkiness of the alkyl group.
The Effect of Organic Additives on the Thermodynamic Parameters of Micellization
Authors: Miyagishi Shigeyoshi 
Published: July 2006

Abstract
The CMC values of dodecylammonium chloride and iodide and of hexadecylammonium chloride were measured in water upon the addition of acetone, 1-propanol, and urea at several temperatures. The effects of the additives were most remarkable on the CMC of hexadecylammonium chloride at 45.0 °C. Urea was less effective on the disruption of micelles than acetone, while the addition of 1-propanol was most effective. The enthalpy of micellization became more negative, while the entropy of micellization became less positive, as the additive concentration increased. We divided the standard free energy of micellization into the hydrophobic term, ΔG°n, and the hydrophilic term, ΔG°p. The value of ΔG°p became more negative with the additive concentration and contributed to the stabilization of the micelle, while ΔG°n became less negative. Therefore, it was concluded that the disruption of the micelle in the presence of these organic additives results from an increase in the free energy in the hydrophobic group of the surfactant molecule.
A pH and pNa Study of Aqueous Solutions of Sodium Deoxycholate
Authors: Sugihara Gohsuke , Tanaka Mitsuru 
Published: July 2006

Abstract
The pH and pNa of aqueous solutions of sodium deoxycholate (SDC) were measured at various temperatures. The critical micelle concentrations (CMC) were determined by means of the crooked points on the plot of pH or pNa vs. the SDC concentration. The data obtained were interpreted thermodynamically, and changes in the enthalpy and entropy of micellization were evaluated, from which it was concluded that the hydrogen bond plays a very important role in the micelle formation.
The Approximate Self-Consistent Renormalized RPA: The Electronic Excited States of DNA Bases in the CNDO/S Method
Authors: Ito Hirotoshi , I’Haya Yasumasa J 
Published: July 2006

Abstract
Comments are given upon the approximate self-consistent renormalized RPA(SCrRPA) presented in our previous papar which assumes the correlated ground state wavefunction to be the linear combination of the Hartree-Fock ground state and doubly excited states, in the CI language. The rationalization of the approximate SCrRPA is made from the results computed by the complete SCrRPA, whose recipe is simply made. Finally, a numerical comparison of the several RPA methods is made as to the electronic spectra of four DNA bases by using the CNDO/S method.
Complexes between Nucleotide Base and Amino Acid. II. Crystal Structure of 5-Bromocytosine : N-Tosyl-l-glutamic Acid
Authors: Ohki Minoru , Takenaka Akio , Shimanouchi Hirotaka , Sasada Yoshio 
Published: July 2006

Abstract
The complex crystals of 5-bromocytosine and N-tosyl-l-glutamic acid were obtained from their aqueous solution. The space group is P1 with dimensions of a=10.843(1), b=11.690(2), c=10.879(2) Å, α=122.15(1), β=121.38(1), γ=69.93(1)°, and Z=2. The structure was solved by the heavy atom method and refined by a block-diagonal least-squares method. The undissociated γ-carboxyl group of glutamic acid is bound with O(2) and N(4) of 5-bromocytosine through hydrogen bonds. This interaction mode is different from those found in some cytosine : glycine complexes and cytidine : N-benzyloxycarbonyl-l-glutamic acid complex dihydrate in which the dissociated α-carboxyl group plays a role. This is the first example of interaction between cytosine and the acidic side group of amino acid.
A Single-step Synthesis of 2-Substituted Benzo-azoles
Authors: Suzuki Nobutaka , Yamabayashi Toshiyuki , Izawa Yasuji 
Published: July 2006

Abstract
2-Substituted benzimidazoles (3a and 5a), benzothiazoles (3b and 5b), and benzoxazole (3c) are readily synthesized in good yields by treating (thiobenzoylthio)acetic acid (1) or ethyl dithioacetate (4) with the corresponding o-substituted anilines (2a, 2b, and 2c) in slightly alkaline media at room temperature.
1,3-Benzodithiolylium Salts. Synthesis and Reactions with Nucleophilic Reagents
Authors: Nakayama Jyuzo , Fujiwara Kazuo , Hoshino Masamatsu 
Published: July 2006

Abstract
Various salts of 1,3-benzodithiolylium ion were prepared in excellent yields on treatment of 2-alkoxy- and 2-alkylthio-1,3-benzodithioles with acids in acetic anhydride. The reactions of 1,3-benzodithiolylium tetrafluoroborate (1a) with a wide variety of nucleophilic reagents (alcohols, water, thiols, hydrogen sulfide, primary, secondary, and tertiary amines, ammonia, N,N-dimethylformamide, electron-rich aromatic compounds, active methylene compounds, tropilidene, and sodium borohydride) were studied. In all cases examined, 1a reacted with nucleophilic reagents at the 2-position to give the corresponding 1,3-benzodithioles in good yields, excepting the reactions with tertiary amines and N,N-dimethylformamide which resulted in the formation of dibenzotetrathiafulvalene. Salt 1a was also prepared from 1,3-benzodithiole and trityl tetrafluoroborate.
The Formation and Dissociation of the Solvated Ion-pair in the Excited Pyrene–Dicyanobenzene System
Authors: Hino Tetsuro , Masuhara Hiroshi , Mataga Noboru 
Published: July 2006

Abstract
Nanosecond laser photolysis has been applied to investigate the photochemical primary processes of the pyrene-p-dicyanobenzene system in some solvents. The solvated ion-pair is formed by the excitation and its yield increases as the dielectric constant of the solvent does; this was explained with the empirical equation proposed previously. The dissociation of the solvated ion-pair to free ions was directly observed in moderately polar solvents and the rate constant of the dissociation was determined, which is in agreement with the values calculated by Eigen’s equation. The role of the ion-pair formation in the fluorescence quenching was discussed on the basis of the present results, and it was concluded that some unknown quenching processes other than the triplet formation compete with the solvation to ion-pairs.
Electronic Spectra of Perylene and Coronene Evaporated Films as a Function of Their Crystallinity
Authors: Kamura Yusuke , Shirotani Ichimin , Ohno Koichi , Seki Kazuhiko , Inokuchi Hiroo 
Published: July 2006

Abstract
The absorption spectra of evaporated thin films of perylene and coronene have been studied as a function of their crystallinity. The amorphous films deposited on a low-temperature substrate in vacuo gave rise to “molecular” spectra which are very different from those of the polycrystalline films. The absorption spectra of amorphous films gradually changed with an increase in the substrate temperature to become similar to those of the polycrystalline films.
Metal Complexes of EDTA and Its Related Compounds. II. Geometric Isomers of [Co(X)(trimethylenediamine-N,N,N′-triacetate)] Complexes with X=H2O, NH3, Cl−, and CN−
Authors: Doh Myung-Ki , Ogino Hiroshi , Fujita Junnosuke , Saito Kazuo 
Published: July 2006

Abstract
Three geometric isomers, equatorial-skew, polar-chair and polar-skew, of [Co(X)(trdtra)] (trdtra3−=trimethylenediamine-N,N,N′-triacetate) have been prepared for each X=H2O, NH3 and Cl−, and the structures assigned mainly by comparing their electronic spectra with those of the equatorial-skew and the polar-chair isomers of N-methyl-trdtra complexes reported previously. The cyano complex gives only the polar-chair isomer.
Stereoselective and Stereospecific Reactions. III. Benzoylation, Cyclfzation, and Epimerization of Diols
Authors: Mitsunobu Oyo , Kimura Junji , Iiizumi Ken-ichi , Yanagida Noboru 
Published: July 2006

Abstract
The benzoylation of various classes of diols by means of diethyl azodicarboxylate (1) and triphenylphosphine (2) was carried out at room temperature. When primary–secondary diols were treated with an equimolar amount of benzoic acid (3) in the presence of 1.5 molar equivalents of 1 and 2, reaction mainly Occurred at their primary hydroxyl functions. Secondary–secondary diols gave mono- and dibenzoylated products or cyclic ethers. The course of the reactions depends on the structure of diols used. Thus, intermolecular displacement giving benzoates is a favorable process for 1,3-butanediol, 2,4-pentanediol and trans-1,2-indanediol, while 2,5-hexanediol and trans-1,2-cyclohexanediol afford the cyclized products.
Photochemical Ligand Substitution in Hexakis(aryl isocyanide)chromium(0)–Olefin Systems
Authors: Iuchi Kazuhito , Asada Shintaro , Kinugasa Takashi , Kanamori Koji , Sugimori Akira 
Published: July 2006

Abstract
Isocyanide chromium(0) complexes coordinated by dimethyl fumarate, fumaronitrile and maleic anhydride were prepared photochemically by the irradiation of hexakis(aryl isocyanide)chromium(0) with the corresponding olefin. Tetracyanoethylene reacts with hexakis(aryl isocyanide)chromium(0) thermally without illumination, while acrylonitrile and dimethyl maleate do not react even with irradiation.
Acidic Nature of Chemisorption Sites on Silica-Alumina and Alumina Catalysts. Characterization by UV Spectra of Adsorbed p-Mtroaniline
Authors: Mizuno Koichi , Take Jun-ichiro , Yoneda Yukio 
Published: July 2006

Abstract
Chemisorbed p-nitroaniline (PNA) gives two bands at 245 and 445 nm on silica-alumina and one band at 450 nm on alumina. The present paper deals with the nature of these chemisobed species and of the chemisorption sites. Kinetic studies of PNA chemisorption onto silica-alumina from cyclohexane solution revealed that the chemisorbed species responsible for the 245 nm band was formed with an activation energy by 0.9 kcal/mol smaller than that responsible for the 445 nm band. The two bands on silica-alumina are due conclusively to two different chemisorbed species. Comparison among UV absorption spectra of PNA in various solutions and on various solid surfaces led to the conclusion that the 245 nm band is ascribable to PNA chemisorbed on Bronsted acid sites and the 445 and 450 nm bands to PNA chemisorbed on Lewis acid sites (i.e. surface Al3+ ions).
The Michael Reaction of Silyl Enol Ethers with α,β-Unsaturated Eetones and Acetals in the Presence of Titanium Tetraalkoxide and Titanium Tetrachloride
Authors: Narasaka Koichi , Soai Kenso , Aikawa Yukiko , Mukaiyama Teruaki 
Published: July 2006

Abstract
Silyl enol ethers react with α,β-unsaturated ketones and esters in the presence of TiCl4 or in the coexistence of TiCl4 and Ti(Oi-Pr)4 to give 1,5-dicarbonyl compounds in good yields. The reactions of acetals derived from α,β-unsaturated ketones with silyl enol ethers in the coexistence of TiCl4 and Ti(Oi-Pr)4, followed by successive addition of 1,2-ethanedithiol, give the Michael products, δ-keto ethylene thioacetal, in good yields. The reaction of silyl enol ethers with acetals derived from α,β-unsaturated aldehydes also gives the Michael products when Ti(OCEt3)4 is employed instead of Ti(Oi-Pr)4 in the above experiment and is successfully applied to the simple synthesis of dihydro rose oxide.
A Spectrophotometric Study of Copper(I) Chloro-Complexes in Aqueous 5M Na(Cl, ClO4) Solutions
Authors: Sugasaka Kazuhiko , Fujii Ayako 
Published: July 2006

Abstract
The complex formation of copper(I) ions in aqueous 5 M Na(Cl, ClO4) solutions was studied by spectrophotometry covering a pH range from acidic to alkaline. Over the range of the chloride concentration of 0.05–5 M in acidic solutions, the complexes CuCl2− and CuCl32− were found. The molar extinction coefficients of the complexes were determined at various wavelengths from 220 to 320 nm. The equilibrium constant for the reaction CuCl2−+Cl−=CuCl32− was determined to be 1.95. Chloro-hydroxo mixed complexes of copper(I), such as CuClOH−, CuCl2OH2−, and CuCl(OH)22− were formed in alkaline solutions and the molar extinction coefficients of these species were estimated. The formation constants βpq=[CuCl2+p(OH)q]/[CuCl2][Cl]p[OH]q of the complexes were evaluated to be as follows: β−11=(1.1±0.1)×104,β01=(4.1±0.3)×103, and β−12=(3.8±0.7)×106. No polynuclear complex was formed in the solutions.