bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on Stable Free Radicals. II. Reactivity of Stable Nitroxide Radicals and NMR Spectra of Reaction Products
Authors: Murayama Keisuke , Morimura Syoji , Yoshioka Takao 
Published: July 2006

Abstract
We have isolated coupled products of such stable free radicals as 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (II), cyclohexane-1-spiro-2′-(4′-oxoimidazolidine-l′-oxyl)-5′-spiro-l″-cyclohexane (IV) and 2,2,6,6-tetramethyl-4-oxopiperidine-1-thiyl derived from bis-[2,2,6,6-tetramethyl-4-oxopiperidyl-(1)]disulfide (VII) with a C-radical derived from α,α′-azo-bis(isobutyronitrile). The reactive site in these stable free radicals was studied from the structure of the coupled products. The homolysis of the disulfide (VII) appeared to be accelerated by an attack of the C-radical, 1-methyl-1-cyanoethyl. The NMR spectra of the products suggested a slow inversion of the nitrogen atom in piperidine derivatives.
Thermal Decomposition of 1,1-Disubstituted-3-aryl-3-(aryloxythiocarbonyl)-2-thioureas
Authors: Miyazaki Koshin 
Published: July 2006

Abstract
1,1-Disubstituted-3-(4-chlorophenyl)-3-(phenoxythiocarbonyl)-2-thioureas of the formula R,R′N–C1(=S)–N(p-Cl–C6H4–)–C′(=S)–OC6H5 (II), when kept at an elevated temperature without any solvent, decomposed into the corresponding thionocarbamates of the formula R,R′N–C(=S)–OC6H5 (III), while p-chlorophenyl isothiocyanate was eliminated. A carbon-14-labeling experiment showed that the decomposition proceeded only through the following path:
II→R,R′N–C2(=S)–OC6H5+p-Cl–C6H4–N=C1=S
Kinetic studies of the various II showed that the decompositions were strictly first order. The rate constant at 175°C increased in the order: R,R′=(CH3)2&gt;(C2H5)2&gt;CH3,4-methylbenzyl\gtrsim (n-C3H7)2&gt;CH3, benzyl&gt;CH3, 4-chlorobenzyl. Neither the products nor the rate of the decomposition reaction was influenced by the presence of a radical scavenger. Furthermore, a crossover decomposition reaction did not give any crossover products. On the basis of these results, a possible intramolecular mechanism of the decomposition involving a four-membered cyclic intermediate structure was proposed.
The Solvent Effects in the Acylation of Alcohol. The Effects of Liquid Sulfur Dioxide on the Dissociation of Hydrogen-bonded Alcohol
Authors: Nagai Toshikazu , Abe Hironobu , Tokura Niichiro 
Published: July 2006

Abstract
The reason for the rate-enhancing effect of liquid sulfur dioxide on the rate of the benzoylation of methanol has been studied. The observation of the NMR spectra revealed that the amount of the hydrogen-bonded methanol is decreased (but not completely eliminated) by sulfur dioxide in the liquid SO2-CCl4 system. The existence of a correlation between the rates of esterification and the dissociation of the associated alcohol accounts for the role of the sulfur dioxide as the agent for the dissociation of the methanol-hydrogen bonding during the esterification.
A Kinetic Study on the Homogeneous Liquid-phase Oxidation of Cumene in the Presence of Triphenylsulfonium Chloride
Authors: Ohkubo Katsutoshi , Yamabe Tokio , Fukui Kenichi 
Published: July 2006

Abstract
A kinetic study of the homogeneous liquid-phase oxidation of cumene was carried out in order to clarify the characteristic behavior of triphenylsulfonium chloride as an autoxidation catalyst. The reaction proceeded with no incubation period. The experimental dependence of the rate upon catalyst and hydrocarbon concentrations and also upon the oxygen pressure was reproduced with a good analytic fit by the following equation:
r=k′(RH)1.27(O2)0.68(Cat.)0 (e−at−e−bt) (a, b, and k′ are constants).
A reaction mechanism was proposed to derive the rate equation. It seems likely from this scheme that sulfonium chloride activates molecular oxygen by means of a reversible molecular association with it.
Studies of Acenaphthene Derivatives. XVI. The Wittig Reaction with Acenaphthenequinone
Authors: Tsuge Otohiko , Tashiro Masashi , Shinkai Ichiro 
Published: July 2006

Abstract
The reactions of acenaphthenequinone (III) with several Wittig reagents have been studied. When III was reacted with equimolar amounts of benzylidenetriphenylphosphoranes (IV) at room temperature, the corresponding benzylideneacenaphthenones (V) were obtained in fairly good yields, but the reactions of benzil and phenanthrenequinone with IV did not take place under similar conditions. The reaction of III with two equivalents of IV under severe conditions afforded only V, and no dibenzylidene compounds were obtained. The reaction of III with resonance-stabilized phosphoranes, such as acetonylidene-, phenacylidene- and p-chlorophenacylidenephosphoranes, afforded the expected α,β-unsaturated ketones. In the reaction with ethoxycarbonylmethylenephosphorane, two stereo-isomeric ethoxycarbonylmethyleneacenaphthenones, which were also obtained from the reaction with diethyl ethoxycarbonylmethylphos-phonate, were formed. The structures of the isomers were confirmed on the basis of NMR, UV, and mass spectral studies. Methylenephosphorane reacted with III to give methyleneacena-phthenone in a poor yield. On the contrary, the reaction with ethylidenephosphorane gave bis-2,2′-methyleneacenaphthenone, which was also formed by the reaction of acenaphthenone with glyoxal, in a good yield.
Studies of Acenaphthene Derivatives. XVII. The Reaction of Benzylideneacenaphthenone with Hydrazines
Authors: Tsuge Otohiko , Shinkai Ichiro , Tashiro Masashi 
Published: July 2006

Abstract
The reactions of benzylideneacenaphthenones with hydrazines are reported. The reaction of benzylideneacenaphthenone with hydrazine hydrate in methanol at 40°C gave 1-hydroxy-2-hydrazinobenzylacenaphthylene, which was then cyclized to the 1-acetylpyrazoline by treating it with acetic anhydride. The hydrazino compound reacted with phenyl isocyanate to give the 1:2-adduct, which, when then treated with hydrochloric acid, suffered ring closure to the pyrazoline compound. Under severe conditions with hydrazine hydrate, however, the reductive cleavage reaction took place, giving the hydrazones of both acenaphthenone and benzaldehyde. Similar phenomena were also observed in the reaction with p-substituted benzylideneacenaphthenones. On the other hand, the reaction with phenylhydrazines in ethanol containing sulfuric acid afforded directly the expected pyrazolines, from which pyrazoles were then prepared by treating them with lead tetraacetate. Furthermore, the corresponding pyridazine was formed in the reaction of phenacylideneacenaphthenone with hydrazine hydrate, while the reaction with 2,4-dinitrophenyl-hydrazine gave the pyrazoline compound.
Electronic Absorption Spectra of Unstable Species Formed by the Ultraviolet Irradiation of N,N-Dimethylaniline at 77°K
Authors: Arimitsu Satoshi , Kimura Katsumi , Tsubomura Hiroshi 
Published: July 2006

Abstract
Electronic absorption spectra of unstable species formed by the ultraviolet irradiation of N,N-dimethylaniline (DMA) were studied in various rigid matrices at 77°K. It was concluded that there are two unstable species which exhibit similar absorption spectra in the visible and the near ultraviolet regions. These species were identified with the cation radical ([(Remark: Graphics omitted.)])+ and the neutral radical ((Remark: Graphics omitted.)), based on various experimental results concerning solvent effect, electron attachment, stimulated emission by the infrared light, etc. The molar extinction coefficient of the cation at 470 mμ was found to be about 1200 (l/cm·mol).
Raman Effect in Ferroelectric Sodium Nitrite Crystal. II. Dependence of B2 Type Phonon Spectrum on Propagation Direction
Authors: Tsuboi Masamichi , Terada Minoru , Kajiura Teruo 
Published: July 2006

Abstract
The Raman spectra corresponding to the (bc) component (B2 type vibrations) of the polarizability tensor in the ferroelectric sodium nitrite crystal (C2v20) have been observed with various directions of the phonon propagation. It has been found that one of the B2 Raman lines at 160 cm−1 splits into two components when the phonon propagates in a direction 45° from the c axis in the ac plane. This splitting has been ascribed to an interaction of a B2 and B1 type lattice-vibrations whose frequencies are accidentally equal to each other in the phonon propagation direction now in question.
New Methods of Preparing the Mixed Cyano Cobalt (III) Complexes
Authors: Maki Nobufumi , Sakuraba Shukichi 
Published: July 2006

Abstract
The following new cyano cobalt(III) complexes have been prepared by treating the corresponding chloro complexes with silver cyanide: cis-[Co(CN)2dip2]NO3·7H2O, cis-[Co(CN)2dip2]2-SO4·12H2O, cis-[Co(CN)2en(NH3)2]NO3, [Co(CN)3en(NH3)]·H2O, and trans-[Co(CN)dg2(NH3)]·1/2H2O. This method has also been used in the preparation of the following compounds: cis-[Co(CN)(NO2)en2]NO3·H2O, cis-[Co(CN)(SO3)en2], trans-[Co(CN)(SO3)en2], cis-[Co(CN)-(OH2)en2]SO4·2H2O, cis-[Co(CN)2en2]NO3, cis-[Co(CN)2pn2]NO3, cis-[Co(CN)2phen2]NO3· 6H2O, and cis-[Co(CN)2phen2]Cl·4H2O. Another new method has been attempted in dimethyl sulfoxide or an acetonitrile-water solution by the step-by-step substitution of a chloro ligand with a CN− ion via the monocyanomonochloro complex of the [Co(CN)Cl N4]-type; we thus succeeded in obtaining these dicyano-ammine complexes, trans-[Co(CN)2(NH3)4]NO3·H2O, trans-[Co(CN)2-en(NH3)2]Cl·H2O, and cis-[Co(CN)2(NH3)4]NO3·H2O. The methods of preparing the following new complexes are also described: trans-Na[Co(CN)2dg2]·2H2O, trans-K[Co(CN)2dg2]·3/2H2O, trans-(NH4)2[Co(CN)dg2(SO3)]·4H2O, and trans-H[Co(CN)dg2Cl]·4H2O. The absorption spectra in the visible, ultraviolet, and infrared regions have been measured.
The Chemistry of Protactinium. VII. The Stability of Protactinium (V) in Perchloric Acid and TTA-Benzene Solutions
Authors: Suzuki Shin , Inoue Yasushi 
Published: July 2006

Abstract
With a view to understand the reasons for the confusion in published works as to the chemical behavior of protactinium (V) in a perchloric acid solution, the effect of the contact time and the stability of the perchloric acid solution of the pentavalent protactinium in the TTA-benzene extraction have been investigated in relation to the methods of preparing the solution. Four sample solutions, prepared by various methods, were used, and definite differences among them were observed. Two of them have been confirmed to be very stable and not to suffer a change in their distribution ratios with the time of standing, while the others are unstable-that is, their distribution ratios decrease with standing, thereby reaching a constant value which agrees with that of the former two. However, the value consistent with that obtained from backward extraction is not this constant value but the value obtained from fresh solutions of the latter type. Protactinium species in the TTA-benzene solution are also not stable, and their distribution ratios increase with standing. This increase in the distribution ratio is mainly due to the formation of unstrippable species. The mechanism of this irreversible change is assumed, from the indirect evidence of extraction experiments and absorption spectroscopy, to be the irreversible dehydration of Pa(OH)2T3·HT to form PaOT3·HT in the organic phase. These unfavorable features of the extraction equilibrium should be taken into account in interpreting the results obtained by TTA extraction experiments.
Proton NMR Studies of Substituent Effects. The Hammett-type Relationship in meta- and para-Substituted Formanilides
Authors: Niwa Jun 
Published: July 2006

Abstract
The spectral analyses of 23 meta- and para-substituted formanilides in dimethyl sulfoxide have proved that they exist in an equilibrium of cis- and trans-forms of restricted rotational isomers in the solvent. The chemical shifts of the protons on the formanilides are strongly dependent on the polar nature of the substituent. In the cis-form, the chemical shifts of both the imino and the formyl protons correlate with the Hammett σ0. In the tarns-form, a plot of the chemical shifts of the formyl protons against the σ0-constants reveals a good correlation in the case of meta-derivatives, but serious deivations for the para-substituents, both for the electron-releasing conjugative substituents and for the electron-withdrawing conjugative substituents. The deviations for both types of substituents are in the direction to be anticipated for any important extra conjugative interaction between the para-substituent and the side-chain. The Yukawa-Tsuno equation is precisely applicable to these shifts when we assume that this system has the same γ-value for both types of substituents; the relation is expressed as:
Δδ=−12.0(σ0+1.12Δ\barσR)+0.5.
where Δ\barσR=σ+−σ0 for the electron-releasing conjugative substituents and where Δ\barσR=σ+−σ0 for the electron-withdrawing conjugative substituents (r=0.993, s=0.8). From the solvent effect on the substituents, such as NH2, OH, and COOH, their σ0-values in dimethyl sulfoxide are proposed. It is also deduced that this solvent effect affects principally the part of the inductive contribution in the overall substituent effect.
The Synthesis of Cyclic α-Amino Acids. II
Authors: Kinoshita Mitsuhiro , Yanagisawa Hiroaki , Doi Shuhei , Kaji Eisuke , Umezawa Sumio 
Published: July 2006

Abstract
The reaction of substituted derivatives of α-nitrocinnamates bearing a nitro group or a chlorine atom at the p- or m-position with cyclopentadiene produced corresponding cyclic α-nitro esters(adducts) in a good yields. The reaction of ethyl α-nitrocrotonate with cyclohexadiene gave ethyl 3-methyl-2-nitrobicyclo[2.2.2]-5-octene-2-carboxylate. In the case of an adduct, ethyl 2-nitro-3-(p-nitrophenyl)bicyclo[2.2.1]-5-heptene-2-carboxylate, there could be isolated four diastereoisomers as crystalline forms by column chromatography and fractional recrystallization. The stereochemistry of the four isomeric adducts were established by NMR spectroscopy. The readily available three of those isomers were converted to corresponding pure isomers of amino acids by reduction followed by hydrolysis. From the other adducts the major amino acid isomers or the amino acid mixtures were obtained in an analogous route.
Intramolecular Interaction between the Hydroxyl Group and the Cyclopropane Ring
Authors: Oki Michinori , Iwamura Hiizu , Murayama Tetsuo , Oka Isao 
Published: July 2006

Abstract
Cyclopropylcarbinol shows two absorption maxima due to the O–H stretching, the lowerfrequency band being stronger than the higher. The results are interpreted on the basis of intramolecular interaction between the hydroxyl group and the cyclopropane ring. This kind of interaction is not clearly detected with 2-cyclopropylethanol, but 2,2-dicyclopropylethanol and 2-(1-methylcyclopropyl)ethanol give results which are best interpreted by assuming the presence of the interaction. It is concluded, from the findings on rigid molecules, that O–H···cyclopropane interaction is possible when the hydroxyl group approaches the edge within the plane of the ring. The steric effect of the methyl group is also discussed.
Photolysis of Nitrosobenzene
Authors: Tanikaga Rikuhei 
Published: July 2006

Abstract
The mechanism of the photochemical reaction of nitrosobenzene (I) has been investigated. The irradiation of I leads to the formation of a phenyl radical and nitric oxide. The reaction of the phenyl radical with I yields diphenylnitroxide, which is then easily reduced to diphenylamine. The reaction of diphenylamine with the nitric oxide gives C-nitrosodiphenylamines, which are then photochemically oxidized to C-nitrodiphenylamines. On the other hand, I is oxidized to nitrobenzene and is, at the same time, reduced to azoxybenzene and azobenzene. Azoxybenzene is photochemically rearranged to 2-hydroxyazobenzene.
Ignition Delay Time Studies of Hydrogen and Oxygen Reactions through Silent Electric Discharge
Authors: Morinaga Kihei 
Published: July 2006

Abstract
The ignition of hydrogen and oxygen could be induced by the so-called silent electric discharge, and the ignition delay time after the termination of the discharge was found to be proportional to a logarithm of the discharge intensity (pulse current). The proportionality constants in different diluents, argon and helium, were analyzed to yield the net effect of chain breaking in the reaction:
H+O2+M\xrightarrowk4HO2+M
and the rate coefficient, k1, for the reaction:
H+O2\xrightarrowk1OH+O
assuming a third-body efficiency of the diluent gases. It was inferred from the results that the radical reproducing from HO2 significantly lessened the effect of the above chain breaking reaction, the accumulation of radicals seemed to be persistent even in the low-temperature region, where the k1 value was observed not to be above the assumed value of k1[M]/2.
Some Observations on Photolysis of Fused Cyclopentyl Nitrites
Authors: Suginome Hiroshi , Sato Norio , Masamune Tadashi 
Published: July 2006

Abstract
The results of photolysis of three fused cyclopentyl nitrites, Ib, VIIIb, XIV, all of which have 22,27-imino-17,23-oxidojervane framework, are described. In all three cases, competition among the reactions of 11-alkoxyl radical, which led to a variety of products, has been observed. However, the cleavage of α,β carbon-carbon bond to the nitrosoxyl group in these compounds is not the major course of the reaction. It has been found that whenever sterically possible (e. g., Ib), 11-alkoxyl radical in these nitrites is capable of achieving the Barton reaction and the reaction leads to relatively few products. In two cases of these photolyses, the reaction is accompanied by epimerization of the relevant alkoxyl radicals. Some aspects of these transformations are considered in the light of other available data.
Orbital Electronegativities in Molecules and Ionic Character in Molecular Complexes
Authors: Matsunaga Yoshio 
Published: July 2006

Abstract
The orbital electronegativities in the nine aromatic hydrocarbons were estimated on the basis of the ionization potentials and the appearance potentials of the doubly-charged ions. Then, by applying the principle of electronegativity equalization to molecular complexes, the orbital electronegativities in typical electron acceptors were evaluated. The ionic character in single and crystal complexes were discussed in terms of the electronegativities of the component molecules. Consideration of neither the ionization potential of the donor molecule, the electron affinity of the acceptor molecule, nor the orbital electronegativities appeared to be enough to define the ionic character in a complex.
Heat of Immersion of Titanium Dioxide in Water. II. The Effect of the Crystallinity of Anatase
Authors: Omori Teiji , Imai Junichiro , Nagao Mahiko , Morimoto Tetsuo 
Published: July 2006

Abstract
Two kinds of anatase samples which have very large specific surface areas and low crystallinities were prepared, and the interaction between the solid surface and the water molecule was investigated by measuring the water content, the heat of immersion in water, and the infrared spectrum of each sample. Two characteristic features were found in these samples: first, the plot of the heat of immersion vs. the pretreatment temperature did not reveal such a maximum as had been found previously with the crystalline anatase, and second, the heat of surface hydration as calculated from the plot of the heat of immersion vs. the water content was found to be remarkably smaller than with the crystalline anatase. These facts have led us to conclude that, with the anatase samples of a low crystallinity, not only does the rehydration reaction of a surface oxide structure produced at an elevated temperature proceed more easily on immersion in water, but also the heat of rehydration is smaller, than in a sample of a high crystallinity. Moreover, it was found from an infrared spectroscopic investigation that the water molecules physisorbed on the surfaces of large-area samples could be desorbed more gradually than those on small-area samples and remained small in quantity up to near 300°C in vacuo.
A Study of the Low-temperature Oxidation of Cumene in the Presence of Triphenylsulfonium Chloride. Propagation and Termination Steps
Authors: Ohkubo Katsutoshi , Yamabe Tokio , Fukui Kenichi 
Published: July 2006

Abstract
The low-temperature liquid-phase oxidation of cumene using triphenylsulfonium chloride was-studied in order to establish the nature of the activity of sulfonium catalysts and the oxidation mechanism. The oxidation occurs in an autocatalytic fashion below 70°C, while it proceeds in an-auto-retarding fashion above 85°C. This is a characteristic feature of this oxidation. The cause of the deactivation at higher temperatures is mainly the deoxygenation of the assumed complex (Cat.···O2). The decomposition of cumene hydroperoxide and the subsequent formation of α-cumyl alcohol, acetophenone, and dicumyl peroxide were seriously affected by the presence of sulfonium salts. The formation of acetophenone was accelerated thermally, while that of a-cumyl alcohol was not accelerated much, though it was accelerated by the catalyst-oxygen complex. Dicumyl peroxide, once formed in an appreciable amount, was gradually decomposed, both thermally and catalytically. The catalyst was deactivated by the product formed. This phenomenon was attributed to the masking action of oxygen-containing products. The mechanism oxidation was discussed on the basis of these observations.
The Reaction between Mercury(II) and Organic Compounds. VII. The Formation Constant and Analytical Application of the o-(2-Thiazolylazo)-4-chlorophenol-Mercury(II) Complex
Authors: Kai Fumiaki 
Published: July 2006

Abstract
The formation constants of the complex formed between o-(2-thiazolylazo)-4-chlorophenol TACL, and mercury(II) in 2% v/v dioxane-water were logKHgR+=6.21 and logKHgR2=6.10 at μ=0.1 and at room temperature. TACL was suggested as a suitable metallochromic indicator for the direct titrimetric determination of mercury(II) ions at pH 6.7–8.7 with an EDTA titrant. This optimum pH range was rather wide compared with that of the other metallochromic indicators, such as Cu-PAN, XO, and MTB. There were marked colour changes from deep blue to reddish-yellow or to violet at equivalence points. The mercury(II) ions up to 210 mg in 100 ml can be determined within an error of ±0.3% by this method.
Oligomerization of Isoprene by Zirconium Catalysts
Authors: Misono Akira , Uchida Yasuzo , Furuhata Ken-ichi , Yoshida Shohei 
Published: July 2006

Abstract
The oligomerization of isoprene by catalyst systems consisting of a zirconium compound and an organoaluminum compound was studied. Isoprene was dimerized to 2,6-dimethyl-1,trans-3,6-octatriene by a catalyst system consisting of zirconium(IV) n-butoxide and diethylaluminum chloride. The selectivity for this dimer was increased to more than 90% by adding triphenylphosphine or tetrahydrofuran to this catalyst system. The effects of the molar ratio of the catalyst components and those of catalyst species were studied.
Synthetic Studies of 4-Oxo- and 4-Imino-3,4-dihydro-1,3-oxazoles
Authors: Chinone Akiko , Sato Shigeru , Mase Toshiyasu , Ohta Masaki 
Published: July 2006

Abstract
For the purpose of synthesizing new mesoionic compounds of oxazole ring system having oxo group at 4 position, reaction of N-phenylbenzimidoyl chloride with glycolic acid was examined. Only an unexpected rearranged product was obtained. The reaction of N-phenylbenzimidoyl chloride with glycolonitrile successfully afforded the intermediate, which was treated with hydrogen chloride or with picric acid or with acetyl perchlorate to give 4-imino-3,4-dihydro-1,3-oxazole derivatives. Condensation of N-phenylbenzimidoyl chloride with mandelonitrile followed by treatment with acetyl perchlorate gave 4-imino-3,4-dihydro-1,3-oxazole derivative.