bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Structural Study of Di-O-isopropyridene-pentitols by Conversion to the Corresponding Mono-O-benzyl Derivatives
Authors: Nakagawa Toshio , Tokuoka Hisao , Shinoto Kazuhiko , Yoshimura Juji , Sato Tetsuo 
Published: July 2006

Abstract
d-Arabinitol and xylitol were acetonated, benzylated and then hydrolyzed with a mineral acid to afford in good yields the corresponding 1-O-benzyl derivatives, which were identified by a periodate oxidation and a chemical identification. A preferential acetonation of the pentitols is discussed in a view of stereochemistry. Synthesis of 2-O-benzyl-d-arabinitol and 3-O-benzylxylitol are also described.
Resolution of Amino Acids. VIII. The Preparation of the Four Optical Isomers of β-Hydroxyaspartic Acid
Authors: Okai Hideo , Imamura Naokazu , Izumiya Nobuo 
Published: July 2006

Abstract
The ammonolysis of cis-epoxy succinic acid yielded threo-hydroxy-Dl-aspartic acid exclusively, but that of trans-epoxy acid produced a mixture of 68% erythro- and 32% threo-hydroxyaspartic acid. This mixture was separated into the two pure diastereomers through either a Dowex 1 column chromatography or fractional crystallization after the mixture had been changed to ammonium salt. The threo- and erythro-Dl-amino acids so prepared were resolved by optically active lysine and ornithine respectively. The contribution (partial molar rotation) of the α-and β-asymmetric centers to the observed molar rotations of the optically active diastereomeric hydroxyaspartic acids in water and 5 n hydrochloric acid was calculated.
Effect of Pressure on Electrical and Optical Behaviour of Quaterrylene, C40H20
Authors: Shirotani Ichimin , Inokuchi Hiroo , Akimoto Shun-iti 
Published: July 2006

Abstract
The temperature dependence of the electrical resistance of the compressed quaterrylene was studied over the temperature range from 300°K to 1000°K under high pressure. The intrinsic energy gap and also the extrinsic energy gap, which is formed by oxygen adsorbed onto the organic crystals, decreased with an increase in the pressure. These changes were dependent linearly on the pressure. The pressure effect on the absorption spectra of the evaporated film and that on the spectra of the solid solution of quaterrylene were observed. It was found that the value of the peak-shift, 8–9×10−6 eV/bar, is comparable to the contraction of the thermal energy gap, 9×10−6 eV/bar, determined from the temperature dependence of the electrical resistance.
Studies of Metallic Hydrides. I. Synthesis of Stoichiometric Hydrides of Group IVb Metals
Authors: Oka Akira 
Published: July 2006

Abstract
Formerly, hydrides of transition metals were generally treated as solid solutions or as hydrogen-occluding systems. It has been said that the elements in the IVb group of the periodic table, whose hydrides are typically metallic, do not form any stable hydride with a stoichiometric composition. The author intends to report the establishment of a process of synthesizing these hydrides, by which process the conditions necessary for the stoichiometric synthesis of IVb metal hydrides were determined.
A New Method of Continuous Gas Chromatography
Authors: Hiratsuka Shigeo , Ichikawa Atsunobu 
Published: July 2006

Abstract
A method is proposed for the continuous analysis of multi-components mixture of volatile compounds by means of gas chromatograph. In the method, a sinusoidal concentration wave of sample gas mixture is introduced continuously into a column of gas chromatograph and the mole fraction of each component can be determined from the amplitude attenuation and the phase-shift measured at the points of several length along the column. The principle of the method is described and the conditions which have to be considered in selecting the column and the angular frequency are discussed. Experiments with two components, nitrogen and oxygen, gas mixture employing a Molecular Sieve 5A column and the hydrogen carrier gas indicate that the principle is valid and that the continuous analysis of multi-components mixture is successful.
Relation between Paper Chromatographic Rf-Values and Two Phase-Distribution Ratios of Phosphate Ions
Authors: Ohashi Shigeru , Hirai Yoshiaki , Waki Hirohiko 
Published: July 2006

Abstract
An easy and useful method reflecting the behaviors of phosphate ions in paper chromatography was proposed. Under some assumption, the correlations between Rf in the paper chromatography and the distribution ratio Ds or Df in the solvent extraction or in the filter paper batch equilibration were investigated. When the water-miscible solvents are used, Df-values may reflect Rf-values considerably well. If the water-immiscible solvents are used, rather Ds-values reflect Rf-values well. Although the partition only has so far been considered in these types of paper chromatography, the results showed that the adsorption phenomena cannot entirely be ignored in some solvent systems like a basic benzyl alcohol system.
The Optical Resolution and Circular Dichroism of trans(N)-oxalatobis(amino-acidato)cobalt(III) Complexes
Authors: Hidaka Jinsai , Shimura Yoichi 
Published: July 2006

Abstract
Three oxalatobis(amino-acidato)cobalt(III) complexes of a trans(N) type have been resolved into their optically active isomers, and their visible and ultraviolet absorption spectra, circular dichroism spectra, and rotatory dispersion have been measured and discussed. The amino acids used are glycine, β-alanine, and l-α-alanine, the last named of which produces a pair of diastereomeric, not antipodal, isomers in its complex. The two diastereomeric isomers have been separated by means of the solubility difference between them. The splitting of the first absorption band of the complexes has been discussed in relation to the behavior of their CD curves. The absolute configurations of the complexes have been inferred from their CD spectra.
The Chromium(III) Complexes with Ammoniatriacetic Acid. II. The Mixed-ligand Complexes
Authors: Uehara Akira , Kyuno Eishin , Tsuchiya Ryokichi 
Published: July 2006

Abstract
The following chromium(III) complexes containing ammoniatriacetic acid (ATA) and other reagents as “mixed-ligands” were newly prepared: NH4[Cr(ata) (acac)]·H2O (brown black)(I), [Cr(ata)(o-phen)]·4H2O (brown) (II), [Cr(ata)(dipy)] (red brown)(III), (NH4)2[Cr(ata)·(NCS)2]·H2O (purple black)(IV, and K2[Cr(ata)(ox)]·2H2O(purple)(V), where ata, acac, o-phen, dipy and ox are the abbreviations of the ammoniatriacetate ion, acetylacetone, o-phenanthroline, α,α-dipyridyl, and the oxalate ion respectively. On the basis of the chemical analyses, the thermal analyses, and the measurements of the electronic absorption spectra, it may be considered that ATA was coordinated as a tetradentate ligand in all these complexes obtained. Further information on the conductivity in an aqueous solution suggested that the IV and V complexes are aquated instantly to form the complex ion as [Cr(OH)(ata)(H2O)2]−. The values of the effective magnetic moments for these complexes were 3.7–3.9 B. M., nearly equal to the spin-only values of tervalent chromium.
Synthesis of Chelating Agents. IV. Synthesis and Chelating Behavior of 1-Phenyl-ethylenedinitrilo-N,N,N′,N′-tetraacetic Acid and 1,2-Diphenyl-ethylenedinitrilo-N,N,N′,N′-tetraacetic Acid
Authors: Ôkaku Noboru , Toyoda Kazuho , Moriguchi Yoshiki , Ueno Keihei 
Published: July 2006

Abstract
1-Phenylethylenedinitrilo-N,N,N′,N′-tetraacetic acid and dl-1,2-diphenylethylenedinitrilo-N,N,N′,N′-tetraacetic acid have been synthesized by the carboxymethylation of the corresponding phenyl-substituted ethylenediamines. The chelate stability constants of the two ligands have been determined potentiometrically for alkaline earth and selected transition metal ions. The increase in the chelate stability as compared with EDTA was interpreted in terms of the steric effect of phenyl substitutions.
Kinetic Studies of Bimolecular Nucleophilic Substitution. VII. The Rates of the Menschutkin Reaction of Methyl Iodide with Various Primary, Secondary and Tertiary Amines in Benzene Solvent
Authors: Okamoto Kunio , Fukui Suguru , Nitta Issei , Shingu Haruo 
Published: July 2006

Abstract
The nucleophilicity of a series of primary, secondary and tertiary amines, i. e., methyl-amines, ethylamines, n-butylamines, ethanolamines and benzylamines, has been investigated by following the kinetics of the reaction of these amines with methyl iodide in benzene solvent. The effect of substituents attached to nitrogen atom on the nucleophilicity of these amines is interpreted in terms of the antagonism between steric retardation and inductive effect. The low nucleophilicity observed in the case of tertiary amines is ascribed to the steric retardation at the expense of the inductive acceleration by the substituents. No linear correlation of the nucleophilicity of amines with the pKa values has been observed.
Medium-Sized Cyclophanes. IV. The Halogenation Reactions of [2.2]Metacyclophane
Authors: Sato Takeo , Wakabayashi (née Fujimoto) Meiko , Okamura Yoshio , Amada Teruo , Hata Kazuo 
Published: July 2006

Abstract
It has been postulated that, with proper control and choice of reaction conditions, the halogenation reactions of [2.2]metacyclophane might be directed in either of two ways: (A) the addition-oxidation path or (B) the addition-elimination path. An attempted iodination (iodine-silver perchlorate or iodine chloride) or bromination (bromine-iron catalyst) of [2.2]-metacyclophane resulted in the formation of 4,5,9,10-tetrahydropyrene according to the path B reaction. On the other hand, iodination reaction in the presence of nitric acid has been shown to afford 2-iodo-4,5,9,10-tetrahydropyrene, after path A. Both the reactions have been explained by assuming a common intermediate, which is formed by the attack of the halogenonium ion on one ring, accompanied by a simultaneous transannular attack of the generated phenonium ion on the second ring.
Copolymerization of Vinyl Chloride with Ethylene by Ziegler-Natta Catalysts
Authors: Misono Akira , Uchida Yasuzo , Yamada Kunikazu 
Published: July 2006

Abstract
The copolymerization of vinyl chloride with ethylene by various Ziegler-Natta catalysts was carried out in hydrocarbon solvents at 50°C. On the basis of infrared and NMR spectroscopies of the copolymerization products, it was found that the catalyst systems consisting of Ti(O-n-Bu)4 and alkylaluminums can copolymerize vinyl chloride with ethylene, whereas those consisting of VCl4, VOCl3, Cr(acac)3, Mn(acac)3, or Co(acac)3 and alkylaluminums give polyethylene or a mixture of polyvinyl chloride and polyethylene, and are otherwise inactive. Random copolymers were easily obtained by the use of the Ti(O-n-Bu)4-AlEt2Cl and Ti-(O-n-Bu)4-AlEtCl2 catalyst systems. However, with these catalyst systems, polyethylene was obtained, along with a random copolymer, at a high ethylene feed ratio. This fact indicates the existence of two kinds of active sites, responsible to the copolymerization and the ethylene polymerization respectively. The monomer reactivity ratios were found to be r1(vinyl chloride)=2.0 and r2(ethylene)=0.2 for the copolymerization by either the Ti(O-n-Bu)4-AlEt2Cl or the Ti-(O-n-Bu)4-AlEtCl2 catalyst system. The monomer reactivity ratios are not in agreement with those found in the conventional radical copolymerization. Though the copolymerization reaction was completely inhibited upon the addition of radical inhibitors, this does not seem to support a radical polymerization mechanism directly.
Studies of Antibiotics and Related Substances. XXXII. Syntheses of Neamine and Its Analogue
Authors: Tatsuta Kuniaki , Kitazawa Eiichi , Umezawa Sumio 
Published: July 2006

Abstract
Neamine, an antibiotic glycoside, was synthesized from paromamine. The preferential tosylation of the primary hydroxyl group of tri-N-acetylparomamine was followed by the replacement of the tosyloxy group with an azido group. The azido derivative was catalytically hydro-genated and acetylated to give 4-O-(2,6-diacetamido-2,6-dideoxy-α-d-glucopyranosyl)-N, N-diacetyldeoxystreptamine. De-N-acetylation of the product gave neamine. Furthermore, a structural isomer of neamine, namely 6-O-(3,6-diamino-3,6-dideoxy-α-d-glucopyranosyl)-deoxystreptamine, was synthesized from 6-O-(3-amino-3-deoxy-α-d-glucopyranosyl)-deoxystrept amine which was obtained from kanamycin by partial hydrolysis.
Preparation of Esters of Carboxylic and Phosphoric Acid via Quaternary Phosphonium Salts
Authors: Mitsunobu Oyo , Yamada Masaaki 
Published: July 2006

Abstract
When n-valeric acid was treated with allyl diethyl phosphite and diethyl azodicarboxylate, allyl valeriate and diethyl N-(diethyl)phosphoryl hydrazodicarboxylate were obtained in good yields. Similarly ethyl benzoate was obtained in a nearly quantitative yield by the reaction of benzoic acid with triethyl phosphite and diethyl azodicarboxylate. The reaction of carboxylic acid with triphenyl phosphine and diethyl azodicarboxylate in the presence of an alcohol resulted in the formation of the corresponding esters of the carboxylic acid, triphenyl phosphine oxide, and diethyl hydrazodicarboxylate. The mechanisms of these reactions are also discussed.
t-Amyloxycarbonyl as a New Protecting Group in Peptide Synthesis. IV. Synthesis and Use of t-Amyl Azidoformate
Authors: Honda Ichiro , Shimonishi Yasutsugu , Sakakibara Shumpei 
Published: July 2006

Abstract
t-Amyl carbazate (II) was synthesized in a satisfactory yield by the direct hydrazinolysis of t-amyl chloroformate (I). Reagent I was prepared by an improved method, using a stock solution of phosgene in toluene. Reagent II was converted to t-amyl azidoformate (III), as in the case of the t-butyl derivative, and reagent III was used for introducing the t-amyloxycarbonyl (AOC) group into free amino acids, amino acid esters, and peptides. Various new AOC-amino acids were synthesized by the present method. Chloroform was found to inhibit the reaction of reagent III with amino acid esters. A practical and safe method for obtaining large quantities of anhydrous hydrazine is described in the present paper.
On the Sn–O Bond in Some Pyridine N-Oxide Complexes of Tin(IV)
Authors: Kawasaki Yoshikane , Hori Mitsufusa , Uenaka Kazushige 
Published: July 2006

Abstract
The stability constants of several pyridine N-oxide complexes of trimethyltin chloride and dimethyltin dichloride have been measured spectrophotometrically in acetonitrile. The values decrease with an increase in the electron-attracting power of the substituent on the pyridine ring. The infrared spectra of several pyridine N-oxide complexes of tin(IV) have been measured from 60 cm−1 to 5000 cm−1. The Sn–O stretching vibration has been observed in the region of 300—400 cm−1, and the frequency depends considerably on the substituents of the tin atom. The Sn–O stretching frequency in the pyridine N-oxide complexes of tin(IV) is rather lower than those in alkyltin alkoxides, which have a large covalent character in the Sn–O bond, but it is higher than those in trialkyltin carboxylates, which have an ionic character in the Sn–O bond. The Sn–O bond in the pyridine N-oxide complexes has been assumed to have a rather large ionic character, from the fact that the dependence of the stability constant on the substituent of the pyridine ring is similar to that of the pKa of the ligand, and from the fact that the frequency of the Sn–O stretching vibration is rather close to that of the trialkyltin carboxylates.
The Photo-ionization of Molecules in Solutions. V. The Mechanism of the Photo-ionization of an Aromatic Diamine in the Polar Media
Authors: Nakato Yoshihiro , Yamamoto Naoto , Tsubomura Hiroshi 
Published: July 2006

Abstract
The photo-ionization of N, N, N′, N′-tetramethyl-p-phenylenediamine (TMPD) in nonpolar solvents was found to occur by the two-step process, with the triplet state as the intermediate. It will be reported here that the photo-ionization of TMPD in polar solvents occurs by the same two-step process, both at 77°K and at room temperature. The flash method was used for the experiments at room temperature. On the other hand, the photo-ionization of TMPD occurs by the single-photon process in ethanol solutions at room temperature when a naphthalene molecule encounters TMPD in the singlet-excited state. The ionization mechanism will be discussed on the basis of these results.
The Crystal and Molecular Structure of Perchloro-(4, 8-dimethylenetricyclo[3. 3. 2. 01,5]deca-2, 6-diene)
Authors: Furusaki Akio 
Published: July 2006

Abstract
The molecular structure of the compound of the formula C12Cl12, mp 273°C, obtained on the pyrolysis of perchloro-(3, 4-dimethylenecyclobutene) at about 250°C, has been determined by a three-dimensional X-ray crystal analysis. The crystal of the compound is monoclinic with four molecules in the unit cell of the dimensions a=16.78, b=6.80, c=17.10 Å and β=116.5°; the space group is C2⁄c. The positions of all the chlorine atoms were elucidated by using the minimum function method, and then those of all the carbon atoms were obtained from an electron density distribution calculated with the phases of chlorine atoms alone. The positional parameters of all the atoms thus obtained were refined by the block-diagonal matrix least-squares method with anisotropic temperature factors. The final discrepancy factor R is 0.094 excluding zero intensity data. As a result of the present study, it is concluded that the compound is perchloro-(4, 8-dimethylene-tricyclo[3.3.2.01,5]deca-2, 6-diene). Except the contacts between the chlorine atoms attached to the same carbon atom, there are several intramolecular Cl···Cl contacts with distances smaller than twice the ordinary van der Waals radius of the chlorine atom; i.e., 3.06, 3.12, 3.13, 3.18 and 3.32 Å. However, it is found that these very close contacts do not seriously affect the bond lengths and angles in the molecule.
Cylindrical Coordinates of Each Atom in a Helical Polymer for a Given Set of Molecular Parameters
Authors: Kijima Hiromasa , Sato Tomohiro , Tsuboi Masamichi , Wada Akiyoshi 
Published: July 2006

Abstract
A method is given for calculating cylindrical-polar coordinates of each atom in a helical polymer from a given set of bond lengths, bond angles, and angles of internal rotation. This should be useful for an analysis of an X-ray fiber diagram of the helical polymer.
Semi-empirical Self-consistent Field Molecular Orbital Calculation of Transition Energy and Oscillator Strength for the Stacked Complexes of Pyrene and 3,4-Benzopyrene with DNA Bases
Authors: Nagata Chikayoshi , Fujita Hiroko , Imamura Akira 
Published: July 2006

Abstract
The transition energy and oscillator strength of stacked complexes of pyrene and 3, 4-benzopyrene with DNA bases are calculated using semi-empirical ASMO SGF CI method, and they are compared with those of free pyrene or 3, 4-benzopyrene. Among the assumed stacking models, the intercalation-like one with guanine reproduced well the experimentally observed red shift and decrease of absorption coefficient in DNA aqueous solution, and this result seems to support the intercalation-like stacking of these hydrocarbons with the DNA bases.
Asymmetric Epoxidation of l-Menthyl Alkylidenecyanoacetates
Authors: Igarashi Minoru , Midorikawa Hiroshi 
Published: July 2006

Abstract
l-Menthyl alkylidenecyanoacetates have been prepared. The reaction of the esters with hydrogen peroxide in the presence of a base is accompanied by a partial asymmetric synthesis, as is shown by the hydrolysis of the resulting epoxy esters to epoxy acids.
The Synthesis of Carrabiose
Authors: Hirase Susumu , Araki Choji 
Published: July 2006

Abstract
Carrabiose (3, 6-anhydro-4-O-β-d-galactopyranosyl-d-galactose) was synthesized by a series of reactions involving the condensation of methyl 2-O-p-tosyl-3, 6-anhydro-α-d-galactopyranoside with tetra-O-acetyl-α-d-galactopyranosyl bromide, followed by deacetylation, detosylation, and removal of the glycosidic methoxyl group. From the resulting disaccharide, several crystalline derivatives were prepared. All of these derivatives were identical in every respect with the corresponding compounds, which had been obtained from natural sources.
Synthetic Studies of Bacitracin. II. Synthesis of a Cyclic Dodecapeptide, an Analogue of Bacitracin A
Authors: Ariyoshi Yasuo , Shiba Tetsuo , Kaneko Takeo 
Published: July 2006

Abstract
For the purpose of making a total synthesis of bacitracin A, a protected heptapeptide with a ring structure, Nα- (formyl-l-isoleucyl)-cyclo-(l-lysyl-δ-tosyl-d-ornithyl-l-isoleucyl-d-phenyl-alanyl-im-benzyl-l-histidyl-α-methyl-β-l-aspartyl) was first prepared by a high dilution method. After deformylation, it was coupled with a tetrapeptide corresponding to the N-terminal part of bacitracin A, the benzyloxycarbonyl-l-isoleucyl-S-benzyl-l-cysteinyl-l-leucyl-d-glutamic acid (α-azide)-γ-t-butyl ester, to afford an undecapeptide derivative. This was converted to a hydrazide, which was then coupled with β-benzyl-d-isoasparaginate to give the Nα-(benzyloxycarbonyl-l-isoleucyl-S-benzyl-l-cysteinyl-l-leucyl-γ-t-butyl-d-glutamyl-d-isoleucyl)-cyclo-(l-lysyl-δ-tosyl-d-ornithyl-l-isoleucyl-d-phenylalanyl-im-benzyl-l-histidyl-β-l-aspartyl)-d-isoasparagine β-benzyl ester. The removal of all protecting groups from it gave a free dodecapeptide, which has the same amino acid sequence, including optical properties, as that of the structure of bacitracin A proposed by Stoffel and Craig; it is different from the latter only in having the thiazoline ring replaced with the cysteine residue. The synthetic dodecapeptide was tested for biological activity and for the formation reaction of the thiazoline ring.
The Influence of Agitation on the Gas-phase Ethylene Polymerization Induced by γ-Rays
Authors: Kawakami Waichiro , Hagiwara Miyuki , Hosaki Yoshihiko , Machi Sueo , Kagiya Tsutomu 
Published: July 2006

Abstract
The effect of agitation on the γ-ray induced polymerization of ethylene was studied in a gaseous system at a pressure of 400 kg/cm2 and at a temperature of 30°C, with dose rates ranging from 9.0×102 to 3.8×105 rad/hr. Both the rate and the degree of polymerization decreased upon agitation to I. 50% of those in the polymerization without agitation. The kinetical analysis of the experimental results has shown that this decrease in the rate and in the degree of polymerization is mainly due to a decrease in the absolute propagation rate. Further, it was found that agitation has no effect on initiation and transfer reactions. The termination was not effected by agitation under a high dose rate, but it was slightly promoted at lower dose rates.
The Ultrasonic Study of Aqueous Solutions of Urea
Authors: Arakawa Kiyoshi , Takenaka Nobuo 
Published: July 2006

Abstract
An ultrasonic investigation of aqueous solutions of urea was made by means of the pulse technique. The ultrasonic velocity and absorption were measured on solutions of about 14– 43 wt% in the frequency range from 5 to 45 Mc/sec. In an 8 m urea solution the velocity vs. the temperature curve was found to be horizontal in the temperature range from 20 to 40°C. The α/f2vs. logf curves (α, absorption coefficient; f, frequency) showed a very small frequency dependence throughout this experiment. The magnitude of α⁄f2 first decreases upon the addition of urea; at about 4–6 m of urea it reaches a shallow minimum, thereafter slowly increasing. At about 8 m of urea the contribution to the ultrasonic relaxation from the open-packed structure in water completely disappears, and the contribution from the water-urea structure as well as that from the association of urea is small.