bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiation Chemical Studies with Cyclotron Beams. II. The Radiolysis of an Aqueous Ferrous Ammonium Sulfate Solution with Carbon- and Nitrogen-Ion Radiations
Authors: Imamura Masashi , Matsui Masao , Karasawa Takashi 
Published: July 2006

Abstract
The yield of ferric ions in the radiolysis of an aqueous ferrous ammonium sulfate solution has been determined in the very high LET (linear energy transfer) range. The radiations used were ions of carbon-12 and nitrogen-14, which were accelerated by means of the IPCR cyclotron and which had energies (Es) of 31–77 MeV for C-ions and of 17–78 MeV for N-ions; the LET ranges for water were 24–46 eV/Å and 26–85 eV/Å respectively. From the plot of G(Fe3+)Es vs. Es, the value for G(Fe3+) at an infinite LET was found to be in the vicinity of 2.9. It has also been shown that there is a substantial difference in the instantaneous yield (Gi) between the two ion radiations of the same LET; this may be ascribed to the differences in the track structures of the heavy-ion radiations.
Fluorescence Quenching Reactions due to the Intermolecular Electron Transfer Process in Solution
Authors: Okada Tadashi , Oohari Hiroo , Mataga Noboru 
Published: July 2006

Abstract
Mechanisms of the intermolecular electron transfer process in the electronically excited states of solute molecules have been studied in relation to the fluorescence quenching reactions in solution, employing pyrene as a fluorescer and some aromatic amine and cyano compounds as quenchers. The quenchers showed various strengths of the quenching actions which were classified and discussed on the basis of a new theoretical model of electron transfer process in excited state. Tetracyanoethylene showed a quite strong quenching action which was interpreted in terms of a long range electron transfer from excited pyrene to tetracyanoethylene. The relation between the exciplex formation, the electron transfer reaction due to the short range interaction and that due to the long range interaction have been discussed.
Radiolysis of Aqueous Solution of Potassium Periodate
Authors: Bhattacharyya S N , Bardhan D K 
Published: July 2006

Abstract
Aqueous solutions of potassium periodate in neutral medium were irradiated with X-rays and with Gobalt-60 gamma rays. It was observed that the periodate on radiolysis is reduced only to iodate and no other reduction product was detected. A mechanism for the radiation induced reduction of periodate in aqueous solution is proposed and discussed. Effect of methanol on the course of radiolysis has also been studied.
The Copolymerization of Dimethallylidenepentaerythritol and Dicrotylidenepentaerythritol with Maleic Anhydride
Authors: Ouchi Tatsuro , Oiwa Masayoshi 
Published: July 2006

Abstract
Dimethallylidenepentaerythritol (DMAPE) and dicrotylidenepentaerythritol (DCPE) have been copolymerized with maleic anhydride (Manh), using benzoyl peroxide as an initiator. From the results of the UV spectrum concerning the rate of copolymerization, it was found that the copolymerization might proceed on the pseudo-terpolymerization of the charge transfer complex-allylidene group-Manh. The following functional group reactivity ratios were calculated at 60°C in these systems:
& DMAPE(M_1)-Manh(M_2)
& r_1cK=0.77, r_2cK=0.058
& r_1=O.05, r_2=0.025
& DCPE(M_1)-Manh(M_2)
& r_1cK=0.89,  r_2CK=0.057
& r_1=0.02, r_2=0.020
Studies of Unnatural Amino Acids and Their Peptides. IV. The Syntheses of Dl-β-(5-Cytosinyl)-α-alanine Peptides
Authors: Shimada Mitsuhisa , Takeuchi K\={o}ji , Asai Yoshiya , Kuwata Shigeru , Watanabe Hiroshi 
Published: July 2006

Abstract
Dl-β-(5-Cytosinyl)-α-alanine and its dipeptides with glycine were synthesized. The benzyloxycarbonylation of this amino acid afforded the α-N-substituted derivative, but all attempts to obtain the diacylated derivative were unsuccessful. The condensation of the benzyloxycarbonyl derivative with glycine ethyl ester by the carbodiimide method afforded the expected dipeptide, though the yield was low (18%); it was accompanied by a large amount of a bicyclic compound, a lactam produced by an intramolecular acylation. The ethyl ester hydrochloride of this amino acid could not be obtained in a pure state, probably because of its ready cyclization to the same lactam structure under weakly acidic conditions. This complication could be avoided by using the tertiary butyl in place of the ethyl ester. Benzyloxycarbonylglycine p-nitrophenyl ester was condensed smoothly with this ester, affording the expected dipeptide in a 53% yield. The carbodiimide method could also be used, but it was less effective.
Photoinduced Reactions. XLI. Stereochemical Course in the Photochemistry of a 2,5-Cyclohexadienone
Authors: Ogura Katsuyuki , Matsuura Teruo 
Published: July 2006

Abstract
Mechanism for the photochemical transformation of a 2,5-cyclohexadienone into a bicyclo[3.1.0]hex-3-en-2-one (so-called lumiketone) was discussed. Photolysis of 2,4,6-tri-t-butyl-4-methoxy-2,5-cyclohexadienone (VII) gave only one stereoisomer (VIIIa) of the corresponding lumiketones. This fact and the prediction by the Woodward-Hoffmann rule indicate that a biradical-like excited state XI with 3,5-bonding gives rise to a direct rearrangement to lumiketone Villa as shown in Path B (Scheme II).
Formation and Cycloaddition Reactions of Substituted N-Ethoxycarbonyl-1(1H)-azepine Derivatives
Authors: Sasaki Tadashi , Kanematsu Ken , Kakehi Akikazu 
Published: July 2006

Abstract
The formation of substituted N-ethoxycarbonyl-1(1H)-azepine derivatives is reinvestigated in the thermal reactions of benzene derivatives with ethyl azidoformate. The rate-determining step in these reactions is determined by kinetic experiments to be the decomposition of the azide. The (4+2) π cycloadducts of these azepine derivatives are obtained by thermal reactions with tetracyanoethylene (TCNE) as a dienophile. The formation of compounds 22, 23, 24, 25, 26, and 27 is confirmed by the spectral evidence.
The Synthesis of Benzoyl-l-arginine-p-nitroanilide
Authors: Nishi Norio , Tokura Seiichi , Noguchi Junzo 
Published: July 2006

Abstract
Benzoyl-arginine-p-nitroanilide (BAPA) is a synthetic substrate for trypsin, papain, and other enzymes, but it has not yet been prepared in the active l-form, although the preparations of Dl-form and d-form by the trypsin digestion of the Dl-form have been reported. The optically active l-BAPA was prepared by the following route; Nα-carbobenzyloxy-Nω-nitro-l-arginine-p-nitroanilide was prepared from Nα-carbobenzyloxy-Nω-nitro-l-arginine and p-nitrophenyl isocyanate, and the subsequent decarbobenzyloxylation and the benzoylation of this compound gave Nα-benzoyl-Nω-nitro-l-arginine-p-nitroanilide. The removal of the nitro group was followed by Sakakibara’s method using hydrogen fluoride. The l-BAPA shows the same melting point and the same reversal optical rotation as those of d-BAPA. When Nα-benzoyl derivatives of l-arginine were used as starting materials in the preparation of BAPA, Dl-BAPA was always obtained with complete racemization; when Nα,Nω,Nω′-tricarbobenzyloxy-l-arginme as the starting material reacted on p-nitrophenyl isocyanate, the product had no racemization, but the desired l-BAPA was not obtained because one of the carbobenzyloxy groups on the guanido group was extraordinally stable to reagents and could not be removed completely.
Photochemistry of Non-enolizable β-Diketones Containing Cyclopropane Ring in Conjugation
Authors: Okada Taiiti , Kamogawa Koiti , Kawanisi Mituyosi , Nozaki Hitosi 
Published: July 2006

Abstract
Irradiation of bicyclo[3.1.0]hexane-2,4-diones affords isomeric enol lactones retaining the cyclopropane ring. In contrast, photoreaction of 6,6-dimethylspiro[2.5]octane-4,8-dione in ethanol results in the formation of an isomeric benzofuran derivative and dimedone-acetaldehyde condensation product. Cleavage of the cyclopropane ring is characteristic of the behavior of the latter β-diketone.
The Cyclization of Ethyl Cyanoacetate and Salicylaldehyde or 3-Methoxysalicylaldehyde with Ketones by Means of Ammonium Acetate
Authors: Sakurai Akio , Midorikawa Hiroshi , Hashimoto Yasuo 
Published: July 2006

Abstract
Various substituted benz[f]isoquinolines were readily prepared by the condensation of ethyl cyanoacetate and salicylaldehyde or 3-methoxysalicylaldehyde with aliphatic ketones (acetone, diethyl ketone, methyl pentyl ketone, methyl isopentyl ketone, etc.) or aromatic ketones (acetophenone, o-hydroxyacetophenone, m-nitroacetophenone, propiophenone, etc.) in the presence of ammonium acetate. On the other hand, condensation with cyclic ketones such as cyclopentanone and cyclohexanone gave benz[f]cyclopent[c]isoquinolines and benzo[k]phenanthridines respectively.
The Synthesis of a Series of N-t-Amyloxycarbonyl-oligo-l-proline
Authors: Miyoshi Muneji , Kimura Terutoshi , Sakakibara Shumpei 
Published: July 2006

Abstract
A series of N-protected l-proline oligomers, the di-, tri-, tetra-, penta-, hexa- and octamer, were synthesized by conventional methods. The proline imino-group was protected by the t-amyloxycarbonyl (Aoc) group, and the carboxyl group was protected as the benzyl ester during the synthesis. These Aoc-oligoprolines were valuable in elucidating the relationship between the conformation and the degree of polymerization of the polyprolines. The Aoc-protecting group was useful in purifying the intermediates and in obtaining crystals of the final compounds.
Studies on Nylon Monolayers. I. Pressure-Area Curves for Nylon Monolayers on Water
Authors: Seimiya Toshiko 
Published: July 2006

Abstract
The conditions under which nylon monolayer spread on water exhibits a reproducible and well-defined F-A curve favorable for detailed investigation of the surface chemical properties of nylon were studied. For this purpose monolayers of Nylons 6 and 8 were spread from such solvents as methyl alcohol, methyl alcohol saturated with calcium chloride, aqueous solution of 90% formic acid and the mixture of phenol and benzene in 1 : 3 volume ratio. The effects of the nature of these solvents, the volume of spreading solution, surface aging and substrate pH on the properties of spread film were studied. It was found that the monolayers can be classified into two different types of film, A and B, according to the behavior of F-A curve against compression. The type A film appeared usually at the first compression of the spread film. F-A curve of A film varied according to the nature of the spreading solvent and the film was unstable. It readily underwent change to type B by being allowed to stand after the film was compressed to a certain extent, by increasing the volume of the spreading solution or merely by compressing film A to a sufficiently high surface pressure. F-A curve of type B film obtained was almost independent of the nature of the spreading solvent and repetition of compression and expansion of the film.
Ionic Dissociation. I. A Hückel Molecular-Orbital Treatment of the Dissociation of Carboxylic Acids and Several Azine Compounds
Authors: Yamabe Hiroko , Yonezawa Teijiro , Kato Hiroshi 
Published: July 2006

Abstract
The relationship between the pKa value and the change in the electronic energy, ΔE, in the course of the dissociation, and the electronic structure of various mono-carboxylic acids and several azine compounds are discussed on the basis of the calculation by Hückel methods for σ and π electron systems. The parallelism between the pKa and the calculated ΔE of the acids is observed. The σ electron densities of the –COOH proton and the O− lone pair, which is constituted by the released electron on the dissociation, run parallel with the pka′s. The delocalizability of the lone pair for the electrophilic reaction, and that of the proton for the nucleophilic reaction, have a linear relationship with the pka′s. Similar relations are seen in several azine compounds. Therefore, it may be said that the protonation will take place by means of the electrophilic attack at the lone pair, and that the deprotonation occurs by means of the nucleophilic attack at the proton.
The Electron Spin Resonance of the Mn2+ Ion in Aqueous Surfactant Solutions
Authors: Hasegawa Akinori , Michihara Yasuyoshi , Miura Masaji 
Published: July 2006

Abstract
The ESR spectrum of the Mn2+ ion in an aqueous solution of a surfactant is affected by its concentration. Sodium dodecyl sulfate and sodium decyl sulfate were employed as surfactants in this study. The linewidth of the Mn2+ ion is independent of the concentration of the surfactant in the low-concentration range, but it increases over a certain concentration range and then becomes constant. Two values of CMC were observed by measurements of the conductivity corresponding to the concentrations, where the linewidth of Mn2+ changed abruptly with the concentration of the surfactant. The linewidth broadening above the first CMC was interpreted as being due to the formation of an outer-sphere complex of the Mn2+ ion with a surfactant micelle. The interaction between the counterion and micelle was also investigated on the basis of the ESR spectra of the Mn2+ ion with regard to the effects of the kind of surfactant, the temperature, foreign electrolytes, etc.
The Interaction of Oxygen with Organic Molecules. II. Oxygen Quenching of the Excited States of Adsorbed Aromatic Hydrocarbons
Authors: Ishida Hideyuki , Takahashi Hiroshi , Tsubomura Hiroshi 
Published: July 2006

Abstract
Quenching of phosphorescence and fluorescence of aromatic hydrocarbons adsorbed on powdered porous glass or silica gel have been examined as a function of oxygen pressure. It has been found that the phosphorescence quenching at low temperature can be explained mostly by assuming that only those aromatic molecules having an oxygen molecule or molecules within an effective interaction radius are nonphosphorescent (static quenching model). The fluorescence quenching occurs only at much higher oxygen pressures and it has been proposed that contact pairs between aromatic and oxygen molecules, which have shorter intermolecular distances compared to the distances effective for the phosphorescence quenching and give rise to the charge-transfer absorption bands, are relevant. It has been observed that the excimer fluorescence of naphthalene appearing at a higher sample concentration is more strongly affected by oxygen than the monomer fluorescence. The emission spectra from naphthalene-porous glass adsorbate immersed in liquid oxygen and nitrogen have also been examined. The formation of the singlet oxygen (1Δg or 1Σg+) through the interaction of oxygen with triplet molecules has been confirmed by use of the peroxidation reaction of adsorbed anthracene.