bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resolution of Amino Acids. XII. Preparation of l-2-Amino-5-arylpentanoic Acids, Constituent Amino Acids in AM-Toxins
Authors: Shimohigashi Yasuyuki , Lee Sannamu , Izumiya Nobuo 
Published: July 2006

Abstract
The l-forms of 2-amino-5-(p-methoxyphenyl)pentanoic acid (Amp), 2-amino-5-phenylpentanoic acid (App), and 2-amino-5-(p-hydroxyphenyl)pentanoic acid (Ahp) are constituent amino acids in AM-toxins. The O-methyl linkage of l-Amp was hydrolyzed gradually by heating with hydrochloric acid. A procedure without drastic acid treatment is given for the synthesis and resolution of Amp. Diethyl [3-(p-methoxyphenyl)propyl]acetamidomalonate (3a) was saponified to the corresponding malonic acid (5a), and 5a was converted into acetyl-l-Amp (l-6a) by decarboxylation. The Dl-6a and acetyl-Dl-App were resolved by acylase to afford l-Amp and l-App, respectively. The l-Ahp was prepared from l-Amp by acid treatment.
The Stereoselective Synthesis of threo-3-Hydroxy-4-amino Acids
Authors: Katsuki Tsutomu , Yamaguchi Masaru 
Published: July 2006

Abstract
Two threo-3-hydroxy-4-amino acids, dl-4-amino-3-hydroxy-6-methylheptanoic acid (1) and dl-4-amino-3-hydroxy-2-methyl-5-(3-pyridyl)pentanoic acid (2), the optically active forms of which had been isolated by the acid hydrolysis of some antibiotics, were synthesized stereoselectively from l-leucine and Dl-3-(3-pyridyl)alanine respectively through 2-pyrrolidinone intermediates.
Heterocycles by Cycloaddition. IV. Cycloaddition Reactions of Mesoionic Compounds with a 7-Azabicyclo[2.2.1]heptadiene, and Double Fragmentation of the Adducts
Authors: Matsukubo Hiroshi , Kato Hiroshi 
Published: July 2006

Abstract
Cycloaddition of some five-membered mesoionic compounds with dimethyl 7-tosyl-7-azabicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylate occurs only across the unsubstituted double bond. Pyrolysis of the adducts resulted in a double fragmentation reaction to give two five-membered aromatic heterocycles. A dithiolone adduct gave the S-oxide, which was pyrolyzed to the corresponding thiopyran-2-one.
Determination of the Solubility of Oxygen in Copper by the Coulometric Method
Authors: Wada Tetsuya , Fueki Kazuo , Mukaibo Takashi 
Published: July 2006

Abstract
The solubility of oxygen in copper was determined at 800–1000 °C by means of the coulometric method. The data obtained is represented by the following equation: logN(atom fraction)=−2.164–1820⁄T
X-Ray Photoelectron Spectroscopy of Aminobenzoic Acids and Anthranilic Acid Chelates
Authors: Yoshida Tooru , Sawada Shigemasa 
Published: July 2006

Abstract
Photoelectron spectra of three isomers of aminobenzoic acid and several metal chelates of o-isomer were measured. It was confirmed that o- and p-isomers exist in the non-polar form and m-isomer in the dipolar. In the chelates the trend was for the N(1s) chemical shifts to increase in parallel with the metal electronegativities.
NMR Studies of the Pyridine Exchange Reaction in the Pyridine Adduct of Bis(salicylaldehydato)nickekl(II)
Authors: Iwaizumi Masamoto , Migita Kouto , Isobe Taro 
Published: July 2006

Abstract
The pyridine exchange reaction in the pyridine adduct of bis(salicylaldehydato)nickel(II) becomes appreciably slower and its activation energy increases with the decrease of the electron donor properties of the in-plane ligand. However, changes in the spin delocalization onto the coordinated pyridine by the in-plane ligand appear small.
Reaction of Mercury(II)–Ethylenediaminetetraacetate–Capriquat Complex with Potassium Iodide in 1,2-Dichloroethane and Its Application to the Spectrophotometric Determination of Mercury(II)
Authors: Shimazaki Akira , Sugawara Masao , Kambara Tomihito 
Published: July 2006

Abstract
A mercury(II)-ethylenediaminetetraacetate-methyltrioctylammonium chloride (Capriquat) complex in 1,2-dichloroethane reacts quantitatively with potassium iodide and forms an ion-pair of tetraiodomercurate(II) with a capriquat cation. The composition of the extracted species was determined to be [Hg(edta)(Cq)2]. The reaction was applied to the spectrophotometric determination of mercury(II).
Some Aspects of the Solid-solid Reaction Products between MgO and V2O3
Authors: Oshima Hirotoshi , Yamamura Hiroshi , Shirasaki Shin-ichi 
Published: July 2006

Abstract
This report is concerned with the characterization of the metastably occurring reaction products with the spinel structure of a solid-solid reaction between MgO and V2O3 in an H2 atmosphere. The measurements of the lattice constants and the magnetic properties suggest that the oxygen framework of the product is formed in an early stage of the reaction, followed by the ordering of the magnetic ions in the tetrahedral sites.
Asymmetric Oxidation of Benzyl p-Tolyl Sulfide with Active Halogeno Compounds in the Presence of Optically-Active Alcohols
Authors: Sato Yoshiyasu , Kunieda Norio , Kinoshita Masayoshi 
Published: July 2006

Abstract
The oxidation of benzyl p-tolyl sulfide with active halogeno compounds such as N-bromosuccinimide, N-chlorosuccinimide and t-butyl hypochlorite, affords optically-active benzyl p-tolyl sulfoxide. The absolute configuration of the sulfoxide obtained depends on the chirality of the alcohols used.
Heterocycles by Cycloaddition. III. Dihydroisoindolequinone, the Correct Structure of the Proposed Azatetracyclononanedione
Authors: Matsukubo Hiroshi , Kato Hiroshi 
Published: July 2006

Abstract
Pyrolysis of a cyclopentadienequinone–oxazolone adduct (3) gives a 5,6-dihydro-4,7-isoindolequinone (7) and not an azatetracyclic cage compound (4). The dihydroquinone (7) was dehydrogenated to the corresponding isoindolequinone (9), which was synthesized via alternative routes.
Studies on Heterocyclic Chemistry. XX. Photo-reactions of 5-Benzylideneamino-3-arylisoxazoles in Trialkylamine
Authors: Nishiwaki Tarozaemon 
Published: July 2006

Abstract
Irradiation of 5-benzylideneamino-3-arylisoxazoles at 254 nm in a mixture of trialkylamine and nitrile gives diaminoethanes (reduction), benzamides (oxidation), and isoxazolo[5,4-b]pyridine (cyclization).
Oxidative Ring Cleavage of 3,5-Di-t-butyl-catechol and -o-benzoquinone by Base-Catalyzed Oxygenation
Authors: Nishinaga Akira , Itahara Toshio , Matsuura Teruo 
Published: July 2006

Abstract
The oxygenation of 3,5-di-t-butyl-catechol and -o-benzoquinone in t-BuOH with t-BuOK leads to the direct oxidative cleavage of the C1–C2 bond affording 2,4-di-t-butyl-4-carboxymethyl-2-buten-4-olide, a muconic acid derivative. The reaction is rationalized by assuming the reaction of 3,5-di-t-butyl-o-benzosemiquinone with oxygen.
Studies on Organic Semiconductors. XVIII. Photoconductivity of Heteroaromatic Compounds and Their Substituted Derivatives
Authors: Sugimoto Akira , Kato Shinji , Inoue Hiroo , Imoto Eiji 
Published: July 2006

Abstract
The effects of hetero atoms and substituents on the photocurrents of the parent compounds were investigated by comparison of the photocurrents of 52 specimens of the aza-benzenoid and oxa-benzenoid compounds.
Modification of the Packed-bed Electrode and Its Potential Distribution
Authors: Yoshizawa Shiro , Takehara Zenichiro , Ogumi Zempachi 
Published: July 2006

Abstract
The packed-bed electrode has been investigated in order to scale up the cell capacity by introducing three-dimensional electrode. The reactions of aniline formation by cathodic reduction of nitrobenzene and Fe(II) ion formation by cathodic reduction of Fe(III) ion were studied. When bed particles with high electric conductivity were used, the effective depth of the packed-bed where the electrode reaction took place was very small. However, when particles with moderate resistance were used, the effective depth increased. This is because the potential distribution in the bed material is the same as that in the electrolyte in the bed, the potential difference between particles and electrolyte thus being maintained constant at any position in the bed. From the standpoint of scaling up the cell capacity, this type of electrode can be effectively applied.
Electronic States of Fluorene, Carbazole and Dibenzofuran
Authors: Tanaka Masashi 
Published: July 2006

Abstract
The polarized reflection spectra of the fluorene, carbazole, and dibenzofuran crystals have been measured from 30000 to 53000 cm−1 and the absolute intensity of the absorption parallel to the a, b, and c axes of these crystals has been obtained by the Kramers-Kronig transformation; these data allowed an interpretation to be made for the solution spectra. Furthermore, the influence of the intermolecular interaction on each level has been examined. This analysis shows that the lowest excited state of the fluorene molecule is the B2 state, while those of the carbazole and dibenzofuran are the A1 states. In fluorene, the sum of the oscillator strengths of the transition to two lower excited states (α and α* states) is 0.39 in the molecule and 0.61 in the crystal. Such hyperchromism is also observed in the α, p, and β states of carbazole and the β state of dibenzofuran. On the other hand, the α* state of dibenzofuran is hypochromic and the oscillator strengths in the molecule (0.87) decrease to 0.36 in the crystal. However, the factor group splitting and the crystal field shift are small and a one to one correspondence can easily be obtained between the solution and crystalline spectra.
Hydrogen Atom Transfer in the Quenching of Pyrene Fluorescence by Amines
Authors: Okada Tadashi , Mori Takeshi , Mataga Noboru 
Published: July 2006

Abstract
The mechanism of the quenching of pyrene fluorescence by primary and secondary amines has been studied by means of fluorescence measurements and transient absorption measurements with the use of laser photolysis as well as conventional flash photolysis methods. It has been confirmed that 1-hydro-1-pyrenyl radicals and amino radicals are produced in the course of the fluorescence quenching reaction. The relative yields of 1-hydro-1-pyrenyl radicals for various amine quenchers were estimated.
Studies of MoO3–Al2O3 Catalysts in Ethylene Polymerization. IV. Kinetics and Stoichiometry of the Reduction
Authors: Hashimoto Keizi , Watanabe Shozi , Tarama Kimio 
Published: July 2006

Abstract
In order to reveal the formation mechanism of the active species in ethylene polymerization, the reduction of three kinds of molybdenum oxides, I, II, and III, which are insoluble in aq 10 M-NH3, soluble in aq NH3 but insoluble in water, and soluble in water respectively, was studied under a hydrogen pressure of 170 Torr over the temperature range 350–450 °C. The reduction rate of oxides I and II followed Elovich kinetics with a variable activation energy which increased with the progress of reduction, while that of III followed Elovich kinetics in the multiple kinetic stages and the minimum in apparent activation energy for the reduction lies at the reduction extent of MoO2.7−2.6. The final states of reduction of I, II, and III were MoO2.8−2.6, MoO2.0 and MoO2.2−2.1, respectively. The amount of Mo(V) in each oxide was determined by ESR measurements. The results indicate that Mo(V) in the II is related to the decrease of the apparent activation energy on reduction of III through their mutual interaction. A formation mechanism of the active species, Mo(V) in III, was proposed.
Photochemical Reaction of Ethyl 3-Methyl-3-phenylglycidate in Methanol and Ether Solvents
Authors: Chung Vo Van , Tokuda Masao , Suzuki Akira , Itoh Mitsuomi 
Published: July 2006

Abstract
Irradiation of ethyl 3-methyl-3-phenyl-glycidate (1) in methanol gave an ionic addition product of the solvent, whereas in ether solvent different reaction paths leading to β-keto esters and carbene were observed.
The Chlorination of Norbornadiene by Various Chlorinating Agents
Authors: Onoe Akira , Uemura Sakae , Okano Masaya 
Published: July 2006

Abstract
The chlorination of norbornadiene by CuCl2, TlCl3·4H2O, SbCl5, SeCl4, and VCl4 in CCl4 or CH3-CN afforded mainly trans-3,5-(1) and exo-cis-3,5-dichloronortricyclene (2). In the reaction with PbCl4, Cl2, SO2Cl2, and PCl5, appreciable amounts of exo-5-syn-7-(3) and/or exo-cis-5,6-dichloronorbornene (4) were obtained besides 1 and 2.
Extractive Spectrophotometric Determination of Chromium(III) with 1-(2-Pyridylazo)-2-naphthol
Authors: Subrahmanyam B , Eshwar M C 
Published: July 2006

Abstract
1-(2-Pyridylazo)-2-naphthol reacts with chromium(III), on heating at 80–90 °C for 35 min, at a pH of 3.2–3.7 in presence of acetate buffer. The reddishbrown chelate, extracted into 1-butanol, has two absorption maxima at 555 and 600 nm of equal intensity. The complex obeys Beer’s law in the range 0.3–2.0 μg/ml, has molar absorptivity 1.28×104 at 555 nm.
The Crystal and Molecular Structures of Dichloro-1,2-bis(di-t-butylphosphino)ethaneplatinum(II) and its Chlorobenzene Solvate
Authors: Harada Masahiro , Kai Yasushi , Yasuoka Noritake , Kasai Nobutami 
Published: July 2006

Abstract
X-Ray crystal structure analyses of [PtCl2{(t-Bu)2P(CH2)2P(t-Bu)2}] (I) and [PtCl2{(t-Bu)2P(CH2)2P(t-Bu)2}, C6H5C1] (II) have been carried out. Crystals of I belong to monoclinic system: a=20.595(3), b=7.917(3), c=14.885(2) Å, β=109.03(1)°, space group P21/c with Z=4. II forms monoclinic crystals, P21/c: a=14.873(2), b=13.193(2), c=15.314(2) Å, β=98.75(1)°, Z=4. Both structures, solved by the heavy-atom method, have been refined anisotropically by least-squares procedure to R=0.067 and 0.078 for I and II respectively. There is no essential difference between the structures of [PtCl2{(t-Bu)2P(CH2)2P(t-Bu)2}] molecules in I and II. The coordination around the platinum atom is square-planar; Pt–P=2.262(3) and 2.265(3) Å and Pt–Cl=2.374(4) and 2.365(4) Å. The molecule has a pseudo-C2 symmetry: the platinum atom and the center of the C–C bond in the P–C–C–P lie on this pseudo-C2 axis.
Crystal Vibrations and Intermodular Interactions of CH3X and CD3X (X=Cl, Br, and I)
Authors: Takeuchi Hideo , Bribes Jean-Luc , Harada Issei , Shimanouchi Takehiko 
Published: July 2006

Abstract
Normal coordinate treatments of the crystal vibrations of methyl chloride, methyl bromide, methyl iodide, and their perdeuterated analogs have been made. The values of force constants of non-bonded atom interactions have been determined so as to give the best fit to the lattice frequencies and the splitting frequencies of the intramolecular vibrations. It has been found that the dipole-dipole interactions are essential to account for the splittings of some internal modes, but their effects on lattice frequencies are negligible.
Studies of Nitrogen–Phosphorus Compound. XXVII. Synthesis of N4P4(NH2)8 and Its Hydrolysis
Authors: Kobayashi Etsuro 
Published: July 2006

Abstract
The method for synthesis of N4P4(NH2)8 by the reaction between (NPCl2)4 and ammonia and its hydrolysis behavior were investigated. The reaction of (NPCl2)4 with liquid ammonia took place violently at first, and the resulting product contained more than several percents of an insoluble material. The extract from this product had a rather low yield, about 20–25%. However, such a drastic reaction could be avoided by the addition of a small amount of dioxane to the reaction system; then the insoluble material did not form, and the yield increased to 55–66%. The final product contained P 37–38% and N 50–51%; thus the mole ratio of N to P was exactly 3 : 1 and the composition agreed with that of N4P4(NH2)8·H2O. When an aqueous solution of N4P4(NH2)8 was refluxed at 100 °C, the compound was initially hydrolyzed to PO(NH2)3 and P2O2NH(NH3)4, these being converted into PO(ONa)(NH2)2. At room temperature, the rate of hydrolysis was quite slow, but the composition of the hydrolysis products was similar to that at 100 °C. In a sodium hydroxide solution, N4P4(NH2)8 was converted directly into PO(ONa)(NH2)2 at an elevated temperature. The rate of the alkali hydrolysis obeyed a first-order equation, with the rate constants of 1.0×10−3, 2.5×10−3, 1.9×10−2, and 4.2×10−2 at 50, 60, 80, and 90 °C, respectively. These values were about 2.7 times that of N3P3(NH2)6. The activation energy of the reaction was 20.8 kcal/mol. The acid hydrolysis behavior resembled that in the neutral hydrolysis, but the reaction was accelerated with acid strength. The formation of tetrametaphosphimate by the hydrolysis of N4P4(NH2)8, that had previously been claimed, could not be reproduced in this study.
Structure of Ziegler-Natta Catalysts for the Polymerization of Isoprene
Authors: Uetsuki Masao , Fujiwara Yuzuru 
Published: July 2006

Abstract
Structural investigation was carried out by means of 1H-NMR, ESR, and chemical ionization mass spectrometry on the complexes formed by the reaction of alkylaluminum with titanium(IV) t-butoxide or vanadium(IV) t-butoxide as a catalyst for polymerization of isoprene. The t-butoxide was monomeric in benzene, and reduced to form a bivalent complex via trivalent ones on addition of the alkylaluminum to the solution followed by the formation of two kinds of binuclear aluminum complexes. In the trivalent state the complexes caused polymerization of isoprene to form five kinds of polymers, 1,4-polymerization of isoprene being likely caused by tris[di-μ-t-butoxo-dialkyltitanium(III)]aluminum, or the corresponding vanadium(III) complex. The final product of the reduction of vanadium(IV) t-butoxide was bis(di-μ-alkyl-dialkylaluminum)vanadium(II), which exhibits no catalytic activity.
Photoelectrochemical Reactions at SrTiO3 Single Crystal Electrode
Authors: Watanabe Tadashi , Fujishima Akira , Honda Ken-ichi 
Published: July 2006

Abstract
Electrode characteristics of strontium titanate (SrTiO3) single crystal have been investigated under illumination with light of its intrinsic absorption region. It has been found that the photosensitized electrolytic oxidation of water, known heretofore uniquely on the TiO2 electrode, can proceed also at the SrTiO3 electrode whose anodic dissolution being negligible. Although the photosensitivity of the SrTiO3 electrode is confined to a little shorter wavelength region than that of the TiO2 electrode, the formal quantum efficiency of the photosensitized electrolytic oxidation of water is comparable for these two semiconductor electrodes under intrinsic absorption. In contrast to the case of the TiO2 electrode, the electrochemical photocell consisted of the SrTiO3 anode and platinum cathode can work efficiently even when the pH values of the anodic and cathodic compartments are close to each other. This point is discussed in terms of the flatband potential of these semiconductor electrodes.
Steric Control in the Diels-Alder Reaction
Authors: Seguchi Kazuyoshi , Sera Akira , Maruyama Kazuhiro 
Published: July 2006

Abstract
The Diels-Alder reactions of polychlorocyclopentadienes with substituted ethylenes were investigated, and the rates of the reaction and the endo : exo adduct distributions were determined. The introduction of a chlorine atom at the C5 position of cyclopentadiene resulted in an enhanced endo preference for substituents in the adducts, despite the depressed reactivity of the diene. This is contrary to what is to be expected from the so-called “selectivity-reactivity relationship in the Diels-Alder reaction.” The results in this work were explained in terms of steric interaction between the C5-chlorine atom of the diene and the substituent of dienophiles.
The Solution Photodimerization of (E)-p-Nitrocinnamates
Authors: Ishigami Tatsuzo , Murata Tomoji , Endo Tadashi 
Published: July 2006

Abstract
The solution photodimerization of methyl (E)-p-nitrocinnamate has been studied under various conditions. Cis and trans dimers of head-to-head configuration were formed predominantly, the ratio of the dimers being highly dependent on the concentration and the solvent. The sensitization, the quenching phenomena, and the external heavy-atom effect were observed in this photodimerization. It appears likely that the excited multiplicity responsible for the formation of the trans-dimer is the triplet π,π* state and that both the singlet and the triplet π,π* states contribute to the production of the cis-dimer.
pH Effects on the Radical Addition of Hydrogensulfite Ion to Olefins
Authors: Sakumoto Akihisa , Miyata Teijiro , Washino Masamitsu 
Published: July 2006

Abstract
The competitive addition of sodium hydrogensulfite to allyl and 2-methylallyl alcohols was investigated at the pH range from 3 to 5. The relative reactivity of allyl alcohol to 2-methylallyl alcohol decreased with increasing pH. Sulfite radical ion was mainly participating in the addition at pH 5, and hydrogensulfite radical at pH 3. From the kinetic analysis of the pH dependence, the ratio of reactivities of allyl alcohol and 2-methylallyl alcohol toward sulfite radical ion was 0.213, and the same ratio toward hydrogensulfite radical was 0.305. Further, the ratio of reactivities of hydrogensulfite radical and sulfite radical ion toward allyl alcohol was 1.32, and the same ratio toward 2-methylallyl alcohol was 0.927. The dissociation constant of hydrogensulfite radical was the order of 3×10−5(pKa=4.5).
Synthesis of Porcine Motilin by Fragment Condensation Using Three Protected Peptide Fragments
Authors: Shimizu Fumio , Imagawa Kenichi , Mihara Shigeru , Yanaihara Noboru 
Published: July 2006

Abstract
Synthesis of porcine motilin is described. Construction of the entire molecule of this hormone was carried out by the fragment condensation method in solution employing Rudinger’s azide modification, and the resulting protected docosapeptide was deblocked by sodium–liquid ammonia procedure. Purification of the final product was performed by ion exchange chromatography on CM-Sephadex using ammonium acetate as eluent and gel filtration on BiO–Gel P-6. Purity of the synthetic docosapeptide was assessed by TLC in two different solvent systems and amino acid analysis. This polypeptide showed gastric motoractivity stimulating action on 30 min intravenous infusion in dogs in 5 ng/kg/min doses, which is characteristic to porcine motilin.
Substituent Effect on the Dissociation Constants of 5-(Substituted Styryl)-2-aminotropones
Authors: Kobayashi Toshio , Imafuku Kimiaki , Matsumura Hisashi 
Published: July 2006

Abstract
The dissociation constants of various 5-styryl-2-aminotropones were determined spectrophotometrically using 50%(v/v) aqueous methanol and correlated by the use of Hammett equation, with ρ=0.57.
N-Halogen Compounds of Cyanamide Derivatives. VIII. A Convenient Method of Preparing 1,2,4-Oxadiazoles from N-Haloamidino Compounds
Authors: Fuchigami Toshio , Odo Keijiro 
Published: July 2006

Abstract
A new, efficient method for the preparation of 1,2,4-oxadiazoles from N-benzoylamidino compounds by treatment with t-butyl hypochlorite and sodium hydroxide has been devised. It was supposed that the ring formation proceeds via a nitrene intermediate.
Synthesis of Streptolidine from d-Xylose
Authors: Kusumoto Shoichi , Tsuji Shinichi , Shima Keiyuu , Shiba Tetsuo 
Published: July 2006

Abstract
An alternative total synthesis of streptolidine (roseonine, geamine) was achieved starting from d-xylose. Direct azidolysis of methyl 2,3,5-tri-O-mesyl-α-d-xylofuranoside (6a) afforded methyl 2,3,5-triazido-2,3,5-trideoxy-α-d-arabinofuranoside (9a), whereas the β-anomer of 6a gave only 3,5-diazido-3,5-dideoxy-2-O-mesyl-β-d-ribofuranoside (8b) indicating that the glycosidic configuration in the furanoside system has a decisive influence on the reactivity of the 2-mesyloxy group. However, the β-anomer of diazide (8b) was anomerized to α-anomer which readily undergoes azidolysis to give the triazide (9a). The triazide was successively hydrogenated, benzyloxycarbonylated, and then hydrolyzed to give 2,3,5-tris(benzyloxycarbonylamino)-2,3,5-trideoxy-d-arabinofuranose, which was identical with that prepared from d-ribose. Streptolidine could be synthesized from this key intermediate.