bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Optical Rotatory Dispersion and Circular Dichroism of Aromatic Amino Acids
Authors: Sakota Naokazu , Okita Kozo , Matsui Yasuhiko 
Published: July 2006

Abstract
The CD and ORD of d-phenylglycine and l-phenylalanine were measured at various pH’s. The superficial small pH dependence of the CD maximum around 220 mμ and the anomalous large [θ] value at the CD maximum in both aromatic amino acids suggest an interaction between the 1La transition of the benzene ring and the n→π* transition of the carboxyl group. The ORD and CD of l-α-amino-β-benzalpropionic acid, l-α-amino-β-benzylpropionic acid, and l-2-amino-4-phenyl-butanol-1 were also measured, and the screening effect of the methylene groups which exist between a benzene ring and an asymmetric carbon atom was discussed.
Selectivity in the Metal-Complex-Catalyzed Decarboxylation of Oxaloacetic Acid and a Role of Metal Ion in an Enzyme System
Authors: Munakata Megumu , Matsui Masakazu , Tabushi Masayuki , Shigematsu Tsunenobu 
Published: July 2006

Abstract
The catalytic action of metal ions in the presence of various coordinating agents and a role of metal ions for the activations of an enzyme in a decarboxylation reaction were investigated. Many of the ligands studied decreased the catalytic activity of metal ions. However, α,α′-dipyridyl selectively enhanced the catalytic activities of divalent metal ions, except Cu2+. The activity of Cu2+ was specifically enhanced only with histidine and its derivatives. Histidine destroyed Ni2+ and Co2+ catalysis. The specific enhancement may be due to the increase in the electronegativities of the metal ions with dπ (metal)-pπ(ligand) back donation and to the stereo-configuration of the metal complexes. The catalytic behavior in these metal ion coordinating agent systems was different from that in the metal-enzyme systems. It was assumed that the activation of enzyme resulted from the change in the configuration of enzyme by the coordination of metal ions, and not from the catalytic action of metal ions enhanced by the coordination of enzyme. This was supported by the fact that the catalysis of compounds containing amino groups, active sites of enzyme, remarkably depended on the stereo-configuration. In the enzyme-model system, Mn2+ was generally preferable to Cu2+ and Ni2+. The catalytic actions of Cu2+ and Ni2+ were lowered by the complex formation with the active sites. This may solve the question why, in enzymatic reactions, Mn2+ having small complex-forming ability is more selective and effective than Cu2+ and Ni2+ with large complex-forming abilities.
A Novel Reduction in the Presence of Precipitated Metals. II. The Behavior of Precipitated Metals and Water in Catalytic Reduction
Authors: Sakai Koji , Ishige Masayoshi , Watanabe Ken-ichi , Hata Kazuo 
Published: July 2006

Abstract
The ppt-metal-catalyzed reduction, which is performed by refluxing the substrates with water in the presence of ppt-metals, was investigated in detail. The participation of water as a hydrogen donor was demonstrated by the fact that benzaldehyde was reduced to the corresponding deuterated alcohols when heated with D2O in the presence of ppt-Ni. The scope of the reduction was established by the reaction of cyclohexanone with ppt-metals and water. The most preferable H2O/cyclohexanone molar ratio was found to be about 15 : 1. The reaction was accelerated when a 0.25n aqueous solution of sodium chloride was used instead of water. It was found that the order of the abilities of various ppt-metals to decompose water is different from that of the abilities to catalyze the reduction of cyclohexanone. The values of the activation energies for the reduction catalyzed by ppt-Ni and ppt-Ni,Co were found to be 4.0 kcal/mol and 7.5 kcal/mol respectively. From these facts, it was concluded that the ppt-metal-catalyzed reduction consists of two steps: the reaction of water with zinc or zinc compounds to supply a hydrogen source necessary for the hydrogenation, followed by ordinary catalytic hydrogenation.
The Photosensitized Reaction of Deoxyguanosine in the Presence of Methylene Blue
Authors: Fujita Hitoshi , Yamazaki Hideo 
Published: July 2006

Abstract
The kinetics of the photosensitized decomposition of deoxyguanosine with methylene blue was studied by means of spectrophotometric measurements. The reaction rate increased with an increase in the concentration of the reactant or of oxygen up to a saturation level for each case at a given concentration of the dye. In a buffer solution of a lower phosphate concentration, a larger rate was observed. On the basis of these dependencies of the rate, the reaction scheme was discussed, and the ratios of some rate constants were estimated based on Schenck’s mechanism. A preliminary NMR measurement of the protons of deoxyguanylic acid in D2O suggested that the basepart of the nucleotide was specifically attacked by this photosensitized reaction.
Rearrangement of Aryl Sulfides in the Presence of Aluminum Chloride
Authors: Fujisawa Tamotsu , Ohtsuka Noriko , Tsuchihashi Gen-ichi 
Published: July 2006

Abstract
Aluminum chloride-catalyzed rearrangement of aryl sulfides leads to thermodynamically controlled equilibrium mixtures at room temperature. On treatment of o-, m- or p-tolyl phenyl sulfide without solvent, the isomer distribution converges to an equilibrium point, 17% ortho, 47% meta and 36% para isomer by intramolecular isomerization. Intermolecular disproportionation by methyl-group exchange to produce diphenyl sulfide and ditolyl sulfide accompanied isomerization. In addition, a new type of aromatic rearrangement, intermolecular disproportionation by exchange of the arylthio group, was found to occur simultaneously giving benzene, toluene and thianthrene derivatives. The rate of this reaction is slower than that of the methyl rearrangement. A similar treatment of α-naphthyl phenyl sulfide gave the β-isomer from intramolecular isomerization and diphenyl sulfide, naphthalene, thianthrene and benzene from intermolecular disproportionation. The mechanisms of the rearrangement of aryl sulfides are discussed.
The Graft Copolymerization of a Vinyl Monomer Containing a Glucose Residue onto Polypropylene Fiber
Authors: Iwakura Yoshio , Uno Keikichi , Kojima Takakazu , Ueno Akihiko 
Published: July 2006

Abstract
The graft copolymerization of 3-O-methacryloyl 1,2; 5,6-diisopropylidene-α-d-glucofuranose (MDG) onto polypropylene fibers was carried out by the γ-ray pre-irradiation technique in the presence of oxygen. The isopropylidene groups of the glucose residue grafted on the copolymer were removed by hydrolysis in aqueous formic acid, and the hydroxyl and hemiacetal groups were regenerated. The deacetonated fibers exhibited a considerable affinity for water vapor and could be dyed with a reactive dye.
Transformation of Progesterone by Aspergillus niger 100 and Rhizopus nigricans REF, 129
Authors: Sallam Lotfy , El-Refai Abdel-Monem , El-Kady Ismail 
Published: July 2006

Abstract
The microbiological transformation of progesterone by the local moulds Aspergillus niger and Rhizopus nigricans was studied. To a 48 hr old culture, progesterone (0.4 g/l medium) dissolved in ethanol was added and the transformation was left to proceed for 72 hr. Thereafter, the different transformation products were resolved chromatographically. The identity of each product was established through the determination of mp, mixed mp, optical rotation and ultraviolet as well as infrared absorption spectra. A comparison of the Rf values of each product with that of the corresponding reference using different solvent systems as well as their colours with two spray reagents was used as a further proof for the identity of the isolated products. In case of A. niger, progesterone was converted to 17α-hydroxyprogesterone; 21-hydroxyprogesterone (cortexone); 11α-hydroxyprogesterone; 11α,17α-dihydroxyprogesterone; 6β,11α-dihydroxyprogesterone and 11α, 17α, 21-trihydroxyprogesterone (epicortisol). These products together with 11α-hydroxy-5α-pregnane-3,20-dione were also identified in case of R. nigricans.
The Radiolysis and Photolysis of Methanolic Solutions of Eosin. I. The γ-Radiolysis of Neutral and Alkaline Solutions
Authors: Kimura Kazuie , Miwa Takuji , Imamura Masashi 
Published: July 2006

Abstract
The γ-radiolysis of eosin has been studied in deaerated neutral and alkaline methanolic solutions. Eosin is reduced principally with CH2OH radicals in dilute solutions. In neutral solutions, G(–eosin) is about 2 at the eosin concentration of 10−5m and increases as the concentration of eosin is increased. The final products are leuco-eosin and an unidentified substance which has an absorption peak at 455 nm. In an alkaline solution (10−5m), G(–eosin) is about 4 and the product is semireduced eosin, which is stable in the dark and which undergoes photo-debromination. The ESR spectrum of semireduced eosin has also been recorded. Comparative studies have also been made on uranin solutions.
Thermodynamic and X-Ray Studies of Solid Solutions of Silver Bromide and Lithium Bromide
Authors: Tsuji Toshihide , Murakoshi Shunichi , Fueki Kazuo , Mukaibo Takashi 
Published: July 2006

Abstract
A miscibility gap in AgBr-LiBr solid solutions has been found by the high temperature X-ray diffraction method, and a new phase diagram is presented. Activity, partial molar free energy, enthalpy and entropy of AgBr in AgBr-LiBr solid solutions have been obtained at 350 and 400°C from the e.m.f. data of galvanic cells of the type Ag/AgBr-LiBr/Br2. It has been found that the solid solution forms a regular solution dinned by Hildebrand.
The Photochromism, Thermochromism, and Piezochromism of Dimers of Tetraphenylpyrryl
Authors: Maeda Koko , Chinone Akiko , Hayashi Taro 
Published: July 2006

Abstract
By the oxidation of tetraphenylpyrrole, two types of dimers of tetraphenylpyrryl were obtained. One dimer showed piezochromism and thermochromism, while the other showed photochromism and thermochromism. These phenomena were found to correspond to those of the piezochromic and photochromic dimers of triphenylimidazolyl obtained from triphenylimidazole. The photochromism, thermochromism, and piezochromism of the dimers of tetraphenylpyrryl are determined to be due to the radical dissociation caused by irradiation, heating, and grinding, the same machanism as that in the case of the dimers of triphenylimidazolyl.
β-Ferrocenyl-α,β-unsaturated Ketones. III. The Conformational Study of β-Ferrocenyl-α,β-unsaturated Ketones by Means of IR Spectroscopy
Authors: Kono Hiromichi , Shiga Mikio , Motoyama Izumi , Hata Kazuo 
Published: July 2006

Abstract
The geometrical and conformational isomerism of various β-ferrocenyl-α,β-unsaturated ketones, most of which had been reported in a previous paper, was discussed on the basis of their IR spectra in the 1700–1600 cm−1 range and their NMR spectra. An unusually strong IR absorption of the olefinic double bond was observed in comparison with that of the carbonyl group. Considering the IR and NMR data, it was concluded that 3-ferrocenyl-1-(p-substituted phenyl)-2-propen-1-ones may mostly exist in a s-cis conformation.
Effect of Carbonyl Compounds on Polymerization by Metal Acetylacetonates
Authors: Kaeriyama Kyoji 
Published: July 2006

Abstract
Some ketones and aldehydes have an accelerative effect on the polymerization of various monomers by various metal chelates of acetylacetone. The conversion increases with an increase in the concentration of these additives in a correspondingly increasing polymerization time. A radical is formed by the equimolar reaction of cyclohexanone and manganese (III) acetylacetonate and by the reaction of two aldehyde molecules and a molecule of the chelate. The , order with a monomer is lowered from 1.64 to 1.13 and to 1.07 by the addition of cyclohexanone and caproic aldehyde respectively. The relation between the polymerization rate and the square root of the chelate concentration is linear without any additive ; concave and convex curves are obtained for the systems containing cyclohexanone and caproic aldehyde respectively. The apparent activation energy is lowered from 19.9 kcal/mol to 13.9 and to 14.3 in the presence of cyclohexanone and caproic aldehyde respectively. The effectiveness of ketones is dependent on the nucleophilicity. A mechanism of the initiation reaction which interprets the molar ratio of reactants, the kinetical parameters, and the spectral data is proposed.
Homolytic Chlorination of Aliphatic Compounds. IV. Chlorination of Chloroalkanes by t-Butyl Hypochlorite
Authors: Kosugi Masanori , Takeuchi Kohji , Migita Toshihiko 
Published: July 2006

Abstract
Chlorination of chloroalkanes by t-butyl hypochlorite was investigated by means of competitive experiment. Relative reactivities thus obtained were compared with those toward hydrogen abstraction by t-butoxy radicals derived from other sources. From the results it was concluded that a main chain carrier of this chlorination was a t-butoxy radical. Structure-reactivity relationships in t-butyl hypochlorite chlorination were also investigated. Linear free energy relationship was found to exist between the reactivities of methyl hydrogen of CH3-X and Taft’s σ* constants for the substituent X,ρ*=−0.69. α-Chlorine substituents were found always to enhance the rate of hydrogen abstraction of this position. Resonance effects of a-chlorine substituent is considered to be more important than in photochlorination with chlorine.
Hydrogen-bonding Effects on the Electron Spin Resonance Spectra of the Anion Radicals of Several Aromatic Amine N-Oxides
Authors: Kubota Tanekazu , Oishi Yoshiko , Nishikida Koichi , Miyazaki Hiroshi 
Published: July 2006

Abstract
The hydrogen-bonding effects of ethanol, phenol, and water on the electron-spin-resonance spectra of the anion radicals of 4-nitro- and 4-cyano-pyridine N-oxides, pyrazine mono- and di-N-oxides, and 4-nitropyridine electrochemically generated in dimethylformamide have been studied quantitatively. The equilibrium constant, K, pertinent to the hydrogen-bonding systems was determined on the basis of analyses of the variation in the hyperfine coupling constant caused by the addition of a proton donor. The active site in a radical anion participating in the hydrogenbonding interaction and the K values were then discussed on the basis of the theoretical calculation of the spin density and the coupling constant of the radicals in the hydrogen-bonding interaction. It has been pointed out that this sort of experiment in hydrogen bonding interaction is also useful for assigning the hyperfine coupling constant to a definite atom in a radical. Last, these K values are used to explain the mechanism of radical formation by the controlled potential electrolysis at different reduction potentials of pyrazine mono- and di-N-oxides in dimethylformamide-ethanol mixed solvents.
Semi-Empirical SCF MO Method for Systems Including All Valence Electrons
Authors: Hirota Fumihiko , Nagakura Saburo 
Published: July 2006

Abstract
For the purpose of evaluating approximate SCF-MO’s for systems including all valence electrons, two semi-empirical methods are presented. One of them (method I) uses non-empirical Coulomb integrals and the other (method II) empirical ones. The orbital energies, charge distributions, and excitation energies are calculated for ethylene, acetylene formaldehyde, carbon monoxide and hydrogen cyanide, and are compared with those obtained by the other semi-empirical and non-empirical calculations and also with the corresponding experimental values. The present methods are found to give rather satisfactory results. The calculated orbital energies are improved by the present methods compared with those by the CNDO type calculation. Calculated charge distributions are well coincident with those of the non-empirical SCF calculation. Calculated dipole moments change in parallel with experimental values from a molecule to another, though the former values are generally larger than the latter.
Reactions of Various Thione-compounds with Epoxides. A New Method for the Transformation of the C=S Bond into the C=O
Authors: Ueno Yoshio , Nakai Takeshi , Okawara Makoto 
Published: July 2006

Abstract
The reactions of propylene oxide (PO) with various thione-compounds containing two α-hetero atoms including dithiocarbamates, thioncarbamates, trithiocarbonates and thioureas, and their cyclic analogs were studied in the presence of triethylamine or boron trifluoride etherate as a catalyst. It was found that most of these thione-compounds reacted with PO at 170–180°C to afford the corresponding one-compounds in good yields. This type of reaction may provide a new method for the transformation of the C=S bonds in thione-compounds into the C=O bonds. Boron trifluoride etherate appeared to be more effective than triethylamine as the catalyst. The mechanism which involves initial cycloaddition of PO to the C=S bond followed by elimination of propylene sulfide was proposed for the transformation. The reactivities of these thione-compounds were significantly affected by whether they are cyclic or open-chain and by the nature of the α-hetero atoms: the cyclic thione-compounds were more reactive then the open-chain analogs except for a pair of thioureas and the enhancement by the α-hetero atoms was in the order: N,O≈N,N&gt;N,S&gt;S,S. Both observations may be interpreted in terms of basicity of the thione-compounds. These results also support the proposed mechanism for the formation of 2-oxazolidones from 2-substituted imino-1,3-dithiolanes with epoxides in our preceding paper.
Location of Gadolinium Ions in Hydrated Oxalate by ESR
Authors: Chi Hsiu 
Published: July 2006

Abstract
Gadolinium oxalate hydrate crystallizes isomorphously as La2(C2O4)3·10H2O, with two molecules in a unit cell of dimensions: a0=11.61+0.05, b0=9.656+0.020, c0=10.22+0.05 Å and β=119.0+0.1°. A detailed study of the d-spacings for the coprecipitates of varying composition in the La-Gd oxalate system was made, and 46 nearest-neighbor pairs were selected for Van Vleck second moment calculation. Agreement of the results of the calculation with those of the experiment justifies the suggested model representing the location of the gadolinium ions in the hydrated oxalate salt.
The Polymerization of α-Amino Acid N-Carboxy Anhydride (4-Alkyl-oxazolidine-dione). IV. A Novel Synthesis of a Block Copolypeptide
Authors: Oya Masanao , Uno Keikichi , Iwakura Yoshio 
Published: July 2006

Abstract
It has been found that, when the polymerization of NCA is initiated with n-butylamine in acetonitrile, the amino end group in the polymer produced which is insoluble in the solvent is active (Y. Iwakura, K. Uno and M. Oya, J. Polym. Sci., Part A-1, 8, 2165 (1968)). The amino end group in the polymer isolated without drying could initiate the polymerization of NCA in acetonitrile. By using this characteristic of the polymer, block copolypeptides consisting of various kinds of α-amino acid and of various chain lengths were synthesized. The solubility of the block copolypeptides in a solvent was different from that of the random copolypeptides obtained by the usual copolymerization of a mixture of NCA in acetonitrile. Sometimes the infrared spectra of the block copolypeptides were different from those of the random copolypeptides.
Asymmetric Hydrogenation of C=N Double Bond with Modified Raney Nickel 1. New Determination Method for the Reaction Mechanism Using Asymmetric Catalyst
Authors: Izumi Yoshiharu , Takizawa Hidemitsu , Nakagawa Kunio , Imamura Ryushichi , Imaida Masami , Ninomiya Toshio , Yajima Shinichi 
Published: July 2006

Abstract
The hydrogenation process of ethyl 2-acetoximinopropionate was investigated by means of a novel technique using asymmetric hydrogenation with an asymmetrically modified R–Ni catalyst. It was found that the hydrogenation of ethyl 2-acetoximinopropionate to ethyl alaninate proceeded in two steps through ethyl acetoxyalaninate, and that the asymmetric hydrogenation was performed in the step of the formation of ethyl acetoxyalaninate from ethyl 2-acetoximinopropionate. Besides, the asymmetric reductive amination of ethyl pyruvate was tested with an asymmetrically modified R–Ni catalyst.
Reaction of Sulfoxides with Acylating Reagents. IV. The Catalytic Effect of Both the Brönsted and Lewis Acids in the Oxygen Exchange Reaction of Diaryl Sulfoxides with Acetic Anhydride
Authors: Kise Masahiro , Oae Shigeru 
Published: July 2006

Abstract
Diaryl sulfoxides undergo oxygen exchange and racemization reaction with acetic anhydide. The rate of racemization of p-tolyl phenyl sulfoxide was found to be twice that of oxygen exchange. The remarkably small substituents effect is also in keeping with the SN2 type mechanism. Addition of acetic acid increases the rate of both the racemization and oxygen exchange. Racemization of sulfoxides is also known to be catalyzed markedly by a small amount of Lewis acid. When the reaction was carried out in the presence of a small amount of both acetic acid and Lewis acid, the ratio of the rate constants, kex⁄krac becomes unity. This may mean that the presence of both Brönsted and Lewis acids facilitates the cleavage of S–O bond by easy protonation (or hydrogen-bonding) or coordination on the sulfoxide oxygen, and the assistance of the nucleophilic attack by acetate becomes less important in the reaction. The larger substituent effect is also in keeping with the SN1 type mechanism.
The Rearrangement of Chromanone Oximes with Lithium Aluminum Hydride
Authors: Ito Shoei 
Published: July 2006

Abstract
The lithium aluminum hydride reduction of 7-methoxychromanone oxime (I) and 7-methoxy-3-methylchromamone oxime (II) gave only the rearrangement product (the 2,3,4,5-tetrahydro-1,5-benzoxazepine derivative). 7-Methoxy-2-methylchromanone oxime (III) and 7-methoxy-2-isopropylchromanone oxime (IV) gave a mixture of the rearrangement product (secondary amine) and the normal reduction product (primary amine). 7-Methoxy-2-t-butylchromanone oxime (V) gave only the normal reduction product. The main conclusions to be drawn from these results are as follows: (1) The chromanone oximes without a C2 substituent give only the rearrangement product. (2) The chromanone oximes with a C2 substituent give a mixture of the normal reduction product and the rearrangement product. (3) The more bulky substituent at C2 gives the more normal reduction product and the smaller quantity of the rearrangement product.
Aminocyclitols. XXII. A Synthesis of Actinamine and Hyosamine
Authors: Suami Tetsuo , Ogawa Seiichiro , Sano Hiroshi 
Published: July 2006

Abstract
Hydrazinolysis of 2,4,5,6-tetra-O-acetyl-1,3-di-O-p-toluenesulfonyl-myo-inositol, followed by catalytic hydrogenation afforded myo-inosadiamine-1,3 via an intermediary 6,7-diazabicyclo[3.2.1]-octane-2,3,4,8-tetrol. In this reaction, the use of N,N′-dimethylhydrazine and N-methylhydrazine, instead of hydrazine, gave actinamine: a component of an antibiotic spectinomycin, and N-methyl-myo-inosadiamine-1,3: an important intermediary compound for a synthesis of Dl-hyosamine, respectively. Details of the convenient syntheses of actinamine and Dl-hyosamine are described.