bluuebunny/crossref_metadata_2025 huggingface dataset:
Photooxygenation Reactions of 4-Flavanols and Benzylic-type Alcohols
Authors: Suzuki Morio , Yamazaki Eiji , Takabe Fumiaki , Morioka Motonobu , Mizuno Hideo , Matsushima Ryoka
Published: July 2006

On irradiation in benzene under oxygen atmosphere cis- and trans-4-flavanols gave flavanones with significant structural effects on the yield: A high cis/trans selectivity and enhancement effect by electron-donating substituents. A series of benzylic-type alcohols showed similar substituent effects. The structure-reactivity relationships were explained in terms of the stereoelectronic requirements for favorable overlapping of intermediates. In order to infer the active oxidant species, the above photoreactions were compared with the oxidations by singlet oxygen and superoxide ion. The involvement of superoxide ion or its related species such as electron transfer complex R+····O2−· was suggested. The effects of additives and solvents were also investigated.
Atmosphere Dependent Photoreaction of 4-Pyridinecarboxylic Ester in Acidic Methanolic Solutions
Authors: Sugiyama Toru , Kusano Yukari , Yagi Kazuya , Ito Yoko , Sugimori Akira
Published: July 2006

The UV-irradiation of methyl 4-pyridinecarboxylate (1) in methanol under oxygen in the presence of sulfuric acid brings about methoxylation at the 3-position of the pyridine ring, while under nitrogen methoxylation and hydroxymethylation occur at the 2-position. The change of photoreactions of 1 caused by oxygen can not be explained either by the promotion of intersystem crossing by O2 or by the charge transfer interactions between 1 and O2.
Differential Scanning Calorimetric Studies on the Thermal Denaturation of Ribonuclease A in Aqueous 2-Methyl-2,4-pentanediol
Authors: Fujita Yukihisa , Noda Yukinao
Published: July 2006

The thermal denaturation of ribonuclease A in aqueous solutions of 2-methyl-2,4-pentanediol(MPD) was investigated by differential scanning calorimetry at pH 5.8, i.e., conditions similar to those used to crystallize the protein, and also at pH 3. A two-state reversible denaturation occurred in aqueous MPD up to 50%(v/v) MPD. Under both conditions the denaturation temperature, Td, decreased almost linearly with increasing MPD concentration; there was a slightly greater effect at pH 5.8. The calorimetric enthalpy, ΔHd, first increased with increasing MPD concentration and then decreased slightly at MPD concentrations above 20–30%. This behavior is analogous to that observed for organic additives, such as ethanol and dimethyl sulfoxide, with denaturing agents. The plot of ΔHd against ΔSd, the denaturation entropy at Td, gave a linear correlation between these parameters, indicating a close relationship between the MPD-induced unstabilization of the protein and the water structure around the protein molecule. The standard thermodynamic parameters for denaturation, ΔG°, ΔH°, and ΔS°, were calculated from Td and ΔHd, assuming a constant heat capacity change. The unstabilizing effect of MPD on the thermal stability of the protein results from that the increase in ΔH°, induced by MPD, is compensated by a large increase in ΔS°, with a resulting decrease in ΔG°; it is in accord with an effect on solvent ordering around the exposed nonpolar groups of the protein. It also indicates a temperature dependence of the MPD effect on the protein stability.
1-Bromo-2-ethoxycyclopropyllithium: A Synthetic Equivalent of 2-Lithio-or 3-Lithiopropenal. Application to the Synthesis of Juvenile Hormone (JH-II), β-Sinensal, and Jasmonoids
Authors: Morizawa Yoshitomi , Kanakura Akihiro , Yamamoto Hajime , Hiyama Tamejiro , Nozaki Hitosi
Published: July 2006

The ethyl vinyl ether-dibromocarbene adduct was lithiated with butyllithium at −95 °C in tetrahydrofuran. The resulting lithium carbenoid 3 was allowed to react with various electrophiles to give 1-substituted trans-1-bromo-2-ethoxycyclopropanes (1) in good yields. The trans relationship of Br and OEt groups was found particularly pertinent to the ethanolysis of 1 producing 2-substituted propenal diethyl acetal derivatives. The reaction has been applied to 1-methoxycyclohexene–dibromocarbene adducts, giving rise hereby 2-substituted 2-cyclohepten-1-one dimethyl acetals under ring enlargement. The transformation has been utilized in the synthesis of a homoterpenoid (JH-II) or a terpenoid (β-sinensal) structure by SN2′ substitution of allylic acetates with lithium dimethylcuprate(I) or iron pentacarbonyl respectively. The reaction products of 3 with aldehydes are oxidized with dimethyl sulfoxide to give cyclopropyl ketones whose ethanolysis in the presence of boron trifluoride ether complex gives β-bromo γ-keto aldehyde acetals. Debromination followed by acidic hydrolysis produces γ-keto aldehydes serving as precursors of dihydrojasmone and cis-jasmone.
Mechanism of the Reactions of Oxomolybdenum(V) Tetraphenylporphyrin Complex with Alcohols in the Presence of Superoxide
Authors: Imamura Taira , Hasegawa Koichi , Tanaka Tetsuya , Nakajima Wataru , Fujimoto Masatoshi
Published: July 2006

The successive addition of ROH (R=CH3 and C2H5) to the dichloromethane solution of MovO(tpp)Br (tpp=meso-tetraphenylporphinato) causes two-step reactions at 25 °C. The products of the first and the second step of the reactions are alcohol complex, [MovO(tpp)(ROH)]Br, and alkoxo complex, MovO(tpp)OR, respectively. In the presence of superoxide ion, O2−, in the dichloromethane solution of MovO(tpp)X (X=Br and NCS) containing alcohol, MovO(tpp)OR is formed through competitive two reaction paths where O2− acts as a proton acceptor and a reducing agent. The reaction steps of the two paths were confirmed by optical and ESR studies.
Practical Procedure for the Chemoselective Reduction of Esters by Sodium Borohydride. Effect of the Slow Addition of Methanol
Authors: Soai Kenso , Oyamada Hidekazu , Takase Masako , Ookawa Atushiro
Published: July 2006

The effect of solvents on the reduction of esters was examined with readily available sodium borohydride which is known to be incapable of reducing such functional groups. In mixed solvents of t-butyl alcohol–methanol or tetrahydrofuran–methanol, various carboxylic esters and lactones were found to be reduced by sodium borohydride to the corresponding alcohols or diols in high yields. Slow addition of methanol to the refluxing mixture of ester and sodium borohydride in t-butyl alcohol or tetrahydrofuran was essential to achieve effective reduction. On the other hand, each individual solvent, methanol or t-butyl alcohol, was not effective for the reduction. The procedure provided a practical method for the functional group selective reduction of esters in the presence of chloro, cyano, carboxylato, carbamoyl, carboxy or nitro groups, which can not usually be performed by lithium aluminium hydride.
Syntheses of the Sex-Attractant of Pine Sawflies
Authors: Kikukawa Tadashi , Imaida Motomasa , Tai Akira
Published: July 2006

In order to establish the stereochemistry of the sex attractant of various species of pine sawflies, (2S,3R,7R)-, (2S,3R,7S)- and (2S,3S,7S)-2-acetoxy- and 2-propionyloxy-3,7-dimethylpentadecane were synthesized. The alcohol moiety of each pheromone was prepared by the coupling of Grignard reagent of C12 block with tosylate of C5 block. The C12 blocks, (R)- and (S)-1-bromo-2-methylundecane, were prepared from (R)-(+)-pulegone. The C5 blocks, (2R,3S)- or (2S,3S)-2-methyl-3-tetrahydropyranyloxy-1-(tosyloxy)butane, were derived from (2S,3S)- or (2R,3S)-2-methyl-3-hydroxybutyric acid prepared by the enantio-differentiating hydrogenation of methyl 2-methyl-3-oxobutyrate over the asymmetrically modified nickle catalyst.
Liquid Crystal Materials with Sulfur Atoms Incorporated in the Principal Structure 1. New Liquid Crystal Compounds with 1,3-Dithiane Ring
Authors: Haramoto Yuichiro , Nobe Atushi , Kamogawa Hiroyoshi
Published: July 2006

2-(p-Substituted phenyl)-5-alkyl-1,3-dithianes, new liquid crystals, were synthesized by the thioacetalization of the corresponding aldehydes and dithiols. These compounds have characteristic supercooling states, exhibit monotropic liquid crystal phases even in the case of long terminal alkyl substituents. The mesomorphic characteristics of these compounds were different from those of the corresponding 1,3-dioxanes, this must originate in the difference in the molecular width caused by the difference in the atomic volume between sulfur and oxygen.
Reaction of N-Aroyl-N-t-butylhydroxylamines with Thionyl Chloride. Synthesis of Substituted Benzohydroximoyl Chlorides
Authors: Uchida Yuzuru , Kozuka Seizi
Published: July 2006

The reaction of N-benzoyl-N-t-butylhydroxylamine with thionyl chloride in carbon tetrachloride gave O-chlorosulfinylbenzohydroximoyl chloride as the main product. On treating with ethanol, the compound gave benzohydroximoyl chloride in good yield. The reaction was applied to the synthesis of substituted benzohydroximoyl chlorides.
Selective Formation of Solute Radicals in the Radiolysis of Neopentane-Cyclopentane Mixtures at 4 and 77 K as Studied by Capillary Gas Chromatography and ESR Spectroscopy
Authors: Tilquin Bernard , Gourdin-Serveniere Catherine , Miyazaki Tetsuo , Fueki Kenji
Published: July 2006

The dimer yields in the radiolysis of the neo-C5H12-cyclo-C5H10 (1 mol%) mixtures at 77 and 4 K have been measured by capillary gas chromatography. Analysis of the results indicates that cyclopentyl radicals are produced selectively at 77 K, while their selective formation is suppressed at 4 K. This result coincides well with the data obtained by ESR spectroscopy.
Disproportionation reaction of Nitrogen Monoxide on CaHY-type Zeolite
Authors: Kanno Yoshinori , Imai Hisao
Published: July 2006

The disproportionation reaction of NO was investigated on CaHY-type zeolite. The relation between pretreatment temperature and activity was determined by the pulse reaction technique, and the dependence of the initial formation rate of N2O on NO pressure was investigated with a gas circulation system. The rate of initial formation of N2O is third order in NO pressure in the lower pressure region (ca. 30 Torr, 1 Torr≈133.322 Pa) and 2.2th order in NO pressure in the higher pressure region (ca. 200 Torr). TPD spectra are composed mainly of three peaks: The first peak is assigned to the unreactive adsorbed NO, the second to the NO produced by the decomposition of N2O3 and left on the zeolite surface, and the third to the N2O remaining. On the basis of the reaction mechanism proposed by Chao and Lunsford, the rate equation for the initial formation of N2O has been derived as α=\bark2K1P3⁄(1+K1P2) where P, K1 and \bark2 are the pressure of NO, an equilibrium constant, and a rate constant, respectively. This equation is in good agreement with experimental results obtained with the gas circulation system.
Adsorptions of Organic Compounds in Basic Solutions
Authors: Urano Kohei , Kano Hisanao
Published: July 2006

The adsorption isotherms of various aromatic compounds on an activated carbon or a polystyrene adsorbent in aqueous solutions and basic solutions were investigated. The adsorption isotherms of nonionic compounds and strong anionic electrolytes in the basic solutions were equal to the isotherms in the aqueous solutions. However, the adsorbed amounts of weak anionic electrolytes decreased with ionization in the basic solutions, and the adsorption isotherms of the non-ionized form and the ionized form of all these compounds except phenol could be expressed by the Freundlich equations with the same values of n. The amounts of those weak anionic electrolytes adsorbed at a desired pH could be calculated from the adsorption isotherms of the non-ionized form and the ionized form and the ionization constants.
Bromochlorination of Alkenes with Dichlorobromate(1–) Ion. I
Authors: Negoro Takeshi , Ikeda Yoshitsugu
Published: July 2006

In the reaction of styrene with chlorine, the added bromide ions were mostly incorporated into the adduct, giving a bromo chloro compound. Tetrabutylammonium dichlorobromate(1–) was found to be an efficient bromochlorinating agent. The reactions of 2-butenes and stilbenes were completely anti stereospecific.
Photoinduced Addition Reaction of 1,4-Dibromo-2,5-piperazinedione with 1-Alkenes
Authors: Itoh Kuniaki , Yamada Hiroshi , Sera Akira
Published: July 2006

Irradiation of 1,4-dibromo-2,5-piperazinedione (1) with olefins in acetonitrile gave mixtures of addition products (1:1-adducts and 1:2-adducts). Addition of 1,2-epoxybutane (a hydrogen bromide scavenger) resulted in enhanced yields of the adducts. Structures of the adducts were elucidated and a reaction mechanism is discussed.
Phosphinyl- and Phosphinothioylamino Acids and Peptides. VIII. New Practical Removal Conditions for the S-Mpt Group and their Application for the Synthesis of Bis[N,N-diallyl-[d-Ala2, l-Leu5]-enkephalyl]cystine
Authors: Ueki Masaaki , Shinozaki Kozo
Published: July 2006

Synthesis of bis[N,N-diallyl-[d-Ala2, l-Leu5]-enkephalyl]cystine, which is expected to be a selective opioid δ-receptor antagonist, was studied. The mercapto group of cysteine was protected by the dimethylphosphinothioyl(Mpt) group. For the removal of this group without damaging the allyl moiety, new mild removal conditions by use of KF/18-crown-6 in a solvent mixture of acetonitrile–methanol are proposed. Bis[d-Ala2, l-Leu5]-enkephalyl]cystine was also prepared in a similar manner.
The Effect of Ethylene Glycol on the Thermal Denaturation of Ribonuclease A and Chymotrypsinogen A as Measured by Differential Scanning Calorimetry
Authors: Fujita Yukihisa , Noda Yukinao
Published: July 2006

The thermal denaturation of ribonuclease A(RNase A) and chymotrypsinogen A in aqueous solutions of ethylene glycol (EG) was investigated by differential scanning calorimetry at several pH values in the acidic region. The calorimetric enthalpies of denaturation, ΔHd, of these proteins increased monotonously with increasing the EG concentration under all the conditions studied. These proteins, however, differed from one another in the variation of the denaturation temperature, Td, with the addition of EG. The Td of chemotrypsinogen decreased slightly with an increase in EG concentration under all the conditions, producing a greater effect at high pH. The Td of RNase A, on the other hand, was almost independent of the EG content at pH 3.8, while at pH 2 and 3, the Td increased slightly with increasing the EG concentration and decreased slightly at pH 5. That is, EG stabilized or unstabilized these proteins against thermal denaturation, in a way which seemed to be dependent on temperature rather than the pH. The standard thermodynamic parameters for denaturation, ΔG°, ΔH°, and ΔS°, which were calculated using Td and ΔH° and assuming a constant heat capacity change, suggested that the slight increase or decrease in ΔG° induced by EG is attributed to whether ΔH° increases as much as ΔS° does or not. These results may be explained on the basis of the effect of EG on the solvation around hydrophobic groups of the protein. The EG effect may depends on the structural properties of proteins such as hydrophobicity and polarity, as well as on temperature.
The Addition Reaction of Substituted Benzenesulfinic Acids to N-Phenylmaleimide
Authors: Matsuda Itsuo , Akiyama Keiichi , Furuta Hiroyuki , Mizuta Masateru
Published: July 2006

The reaction of substituted benzenesulfinic acids with N-phenymaleimide has been carried out, and the products obtained have been identified as sulfones from analyses of their IR, UV, and NMR spectra. From the kinetic investigation, a linear Hammett relationship between the σ-value and logK2/K0 has been confirmed. It is concluded that the nucleophilic attack of the sulfinic acid sulfur atom on the carbon of the C=C bond of N-phenylmaleimide is the rate-determining step.
Synthetic Studies on Quinoxaline Antibiotics. II. Synthesis of Triostin A
Authors: Shin Masaru , Inouye Ken , Otsuka Hideo
Published: July 2006

Triostin A, a cyclic octadepsipeptide, was synthesized with Z–d-Ser[Boc–Ala–MeCys(Bzl)–MeVal]–OH and Z–d-Ser[H–Ala–MeCy(Bzl)–MeVal]–OTce as key intermediates. The synthetic antibiotic was compared with natural triostin A in terms of chromatographic behaviors, NMR spectra, and antimicrobial activity to establish their identity. The NMR data on S,S′-dibenzyldihydrotriostin A showed that this intermediate lacking the disulfide linkage also existed as two conformers in chloroform. This observation excludes the possibility that the conformer equilibrium known to occur with triostin A is a consequence of the reversed chirality of the disulfide bond.
Kinetic Studies of the Oxidation of 2,3-Dihydroxy-2-propenal (Triose Reductone) by the Peroxodisulfate Ion
Authors: Abe Yasuo , Horii Hideo , Taniguchi Setsuo
Published: July 2006

Kinetic studies of the oxidation of 2,3-dihydroxy-2-propenal (triose reductone) by the peroxodisulfate ion (S2O82−) were carried out between pH 4.1 and 5.9 at various temperatures (10–30°C) and for ionic strengths (I) (0.07 to 1.07 M (1 M=l mol dm−3)) which were adjusted using NaClO4. The pH dependence of the reaction rates revealed that the singly-charged anion (RH−) was chiefly responsible for the reaction, while undissociated reductone was inactive to peroxodisulfate ion. The rate constant (k2) of RH− with S2O82− was 0.79 M−1 s−1 at 25°C and I=1.07 M (ΔH\eweq=37 kJ mol−1, ΔS\eweq=−123 J deg−1 mol−1). A relationship of logk2=−0.95±1.88I1⁄2⁄(1+I1⁄2) was found at 30°C.
Photoreduction of 2-Benzoylalkanoates
Authors: Yoshioka Michikazu , Aoki Satoshi , Shimizu Toshio , Hasegawa Tadashi
Published: July 2006

2-Benzoylalkanoates 1 undergo photoreduction with 2-propanol. The photoreduction products are classified into three types according to their origin: the homo-pinacol-type products 2, 5, 7, and 8, the mixed-pinacol-type product 3, and the β-hydroxy ester 6. The product distribution is affected by α-methyl substitution. The α-methyl substitution decreases the percentage of the homo-pinacol-type products and increases the percentage of the β-hydroxy ester.
Conduction Band Formation through the Temporary Anion States in Organic Solids
Authors: Hiraoka Kenzo , Nara Masaji
Published: July 2006

The transmission of low-energy electrons (0–15 eV) through thin films of benzene, toluene, pyridine, aniline, styrene, and cyclohexene was studied. The electron transmission spectra of all the aromatic compounds studied are like each other in their forms. The energies of several prominent peaks in the electron transmission spectra are in good agreement with those of temporary anion states measured in the gas phase. It is suggested that vacant orbitals of free molecules form conduction bands in molecular crystals.
Redox Behavior and Electrochromic Properties of Polypyrrole Films in Aqueous Solutions
Authors: Kuwabata Susumu , Yoneyama Hiroshi , Tamura Hideo
Published: July 2006

Polypyrrole films prepared by anodic polymerization of pyrrole on Pt or SnO2-coated glass show redox behavior in aqueous electrolyte solutions containing a supporting electrolyte alone. Transfer of electrolyte anions into and from the film is involved in the redox reaction similarly with acetonitrile solutions already reported. Insertion of divalent anions into the film occurs in two steps but that of monovalent anions in one step, as judged from corresponding cyclic voltammograms. The change in film color which occurs in the redox reaction of the film was investigated in detail as a function of electrode potential and the charge consumed in the redox reaction. Polypyrrole is a promising material for electrochromic display devices.
The Complex Formation of Organomercury with 8-Quinolinol
Authors: Kuniya Joji , Naito Kunishige , Takei Shinsuke
Published: July 2006

Organomercury(II)(RHg+, R; ethyl, n-propyl, n-butyl) forms two kinds of water-soluble complexes, RHgq and RHg(q)(OH)−, with 8-quinolinol(oxine Hq). These complex-formation reactions are studied by means of spectrophotometry, and the formation constants of these complexes, RHgOH, RHgOAc, and RHg(OH)(OAc)−, in 4%(v/v) ethanol at the ionic strength of 0.1 are determined. Reliable results are obtained for ethylmercury(II) and n-propylmercury(II) complexes.
A General Synthetic Approach of Spirovetivanes. The Synthesis of (±)-Solavetivone, (±)-Hinesol, and Related Compounds
Authors: Murai Akio , Sato Shingo , Masamune Tadashi
Published: July 2006

The synthetic procedure leading to preparation of representative compounds, (±)-solavetivone and (±)-hinesol, of two classes of spirovetivanes, is described. The procedure involves Diels-Alder reaction of 4-substituted 5,6-dihydro-3,5-dimethylanisoles with methyl acrylate and π-cyclization of 4-(2-mesyloxyethyl)-4-prenyl-2-cyclohexen-1-one as key steps (Scheme 1).
Kinetics and Mechanism of Dissociation of (Acetylacetonato)[N-(o-carboxyphenyl)iminodiacetato]chromate(III) Ion in Acidic Media
Authors: Chatterjee Chinmay , Bali Aya Singh
Published: July 2006

Acid-catalyzed dissociation of (acetylacetonato) [N-(o-carboxyphenyl) iminodiacetato]chromate(III) ion has been studied kinetically in aqueous perchloric acid media over a temperature range (60–80 °C). Under these conditions the reaction occurs by two concurrent paths according to the following rate law: Rate=k1[complex]+k2[complex][H+], where k1 and k2 are the appropriate rate constants for the spontaneous and acid-catalyzed pathways, respectively Analysis of the rate data corresponding to the rate constants k1 and k2 suggests solvent assisted dissociation of the complex and its conjugate acid for the two paths, respectively, and that the opening of the chelate ring is rate determining.
Pentane Isomerization Activity of Halogenated Rare Earth Intermetallics
Authors: Imamura Hayao , Kato Yuzo , Tsuchiya Susumu
Published: July 2006

Binary halides formed by treating ErAl3 with halogen elements were subjected to an characterization as skeletal isomerization catalysts for pentane. Halogenation of ErAl3 in the presence of CH2Cl2 or CCl4 gives rise to super-acidic binary halides as a result of formation of V-center-type sites due to excess of halogen species.
Indexing of X-Ray Powder Diffraction Data for Potassium Hexafluorovanadate(III)
Authors: Koyama Koichiro , Hashimoto Yasuhiko , Omori Shinichiro , Terawaki Kazuo
Published: July 2006

X-Ray powder diffraction data for K3VF6 are presented; the α form is monoclinic with a=1.2102(1), b=1.7456(2), c=1.2007(2) nm, β=92.58(1)° at 298K; the β form is monoclinic with a=1.714(2), b=1.237(1), c=0.5479(2) nm, β=91.49(3)° at 453 K; the γ form is tetragonal with a=1.3708(5), c=0.8752(5)nm at 483 K; the low-temperature γ form, which contains a small amount of sodium ion, is tetragonal with a=1.3570(3), c=0.8671(2) nm at 298 K.
The Catalytic Properties of the Pd/Mica Model Catalyst
Authors: Takasu Yoshio , Kasahara Kenji , Matsuda Yoshiharu
Published: July 2006

The apparent activation energy of an H2–D2 exchange reaction on a Pd/mica model catalyst system increased with the decrease in the particle size of palladium. The activity pattern as a function of the mean particle size was of a volcano-type, with a maximum at a particle size around 1.2 nm.
Dielectric Relaxation of Some Aliphatic Ketones in Dilute Solution
Authors: Singh Buta
Published: July 2006

Measurements of the relative permittivity at frequency of 10 GHz, and of the refractive index, have been made at 25 °C for (a) 2-haxanone, (b) 3-hexanone, (c) 3-Methyl-2-pentanone, (d) 3,3-dimethyl-2-butanone, (e) 2-heptanone, (f) heptanal, and (g) cyclohexanone, in dilute solutions of cyclohexane, decalin, and 1,4-dioxane, Dielectric relaxation times have been evaluated. It has been concluded that in the ketones and heptanal under study, dipole reorientation occurs mainly by an intramolecular relaxation process.
Kinetics of Copper(II) Incorparation in a Porphyrin Using Four Copper Salts
Authors: Datta-Gupta Nirmalendu , Malakar Debasis , Datta-Gupta Sukla , Gibson Richard
Published: July 2006

Using excess of acetate, chloride, bromide, and sulfate salts, the kinetics of Cu(II) incorporation in meso-tetrakis (4-benzyloxyphenyl) porphyrin, in DMF solution, at different temperatures, have been done. The thermodynamic parameters have been calculated and a mechanism of Cu(II) insertion proposed.
The Synthesis of Polymeric Catalyst Using Ion Exchange Resin and Its Application for Esterification
Authors: Whang Kyu-Ja , Lee Keun-Im , Lee Yong-Keun
Published: July 2006

The copolymer complexes have been synthesized from cation and/or anion resin with metal catalyst such as aluminum chloride or iron(III) chloride. Electron microprobe X-ray analysis demonstrated that aluminum and iron were distributed uniformly in the copolymer complex. The catalytic activity for esterification of dibasic organic acids was discussed and showed that copolymer complex from porous type cation exchange resin was much better catalyst than that from gel type.
Electrochemical Properties of Adriamycin Adsorbed on a Mercury Electrode Surface
Authors: Kano Kenji , Konse Tomonori , Nishimura Naomi , Kubota Tanekazu
Published: July 2006

The electrochemical behavior of adriamycin has been studied by means of cyclic d.c. and a.c. voltammetry with a hanging mercury drop electrode, quinizarin being used as a model compound. Both adriamycin and quinizarin are strongly adsorbed on the mercury electrode with their aromatic ring planes oriented parallel to the electrode surface, and give two sets of reduction waves. The first wave, due to the quinone moieties of the adsorbed adriamycin and quinizarin, has been explained on terms of a two-step one-electron surface redox reaction. The formal standard redox potentials, semiquinone formation constants, and charge transfer rate constants of the surface redox reaction of the quinone moieties have been determined. Although the reduced form of adriamycin is not very stable chemically, it is converted to a stable and electrochemically active form for a few minutes at pH 4.54. The second wave appearing at more negative potential would be due to a kinetic or catalytic process.
13C-NMR Studies on Conformational Equilibria in Isopropyl Methyl Ether
Authors: Tasaki Kenzabu , Sasanuma Yuji , Ando Isao , Abe Akihiro
Published: July 2006

The energy difference between the two rotational isomers, i.e., Cs and C1, of isopropyl methyl ether has been elucidated from the observed vicinal 13C-1H coupling constant. The conventional Gutowsky method based on the simple rotational isomeric state model tends to give an underestimate, especially when the energy difference is large. A more elaborate treatment, which takes account of the overall profile of the torsional potential energy curve, has been attempted. Adoption of JT=11.0–12.0 Hz for the trans coupling gave a value of 2.2±0.2 kcal mol−1 for the energy difference Ecs–Ec1. This result is consistent with the range (2.4±0.6 kcal mol−1) estimated by the matrix-isolation method as reported by Nakata et al.
The Microwave Spectrum of Acrylaldehyde Oxime
Authors: Niwase Manabu , Kubota Kyoko , Yoshida Kazuhiko , Sakaizumi Takeshi , Onda Masao , Ohashi Osamu , Yamaguchi Ichiro
Published: July 2006

The microwave spectra of acrylaldehyde oxime and its deuterated derivative (CH2=CH–CH=NOD) were observed in the frequency region from 8.5 to 35 GHz. The several a-type R-branch transitions in the ground vibradonal state were identified and the following rotational constants in MHz were determined to be: A=34117±96, B=2363.007±0.011, and C=2210.616±0.011 for normal species and A=33950±103, B=2274.301±0.010, and C=2131.981±0.011 for deuterated species. The most plausible molecular structure to which the spectrum assigned is attributed has been deduced to be a s-trans syn geometrical conformer from the rotational constants experimentally determined. The dipole moment component μa in the ground vibrational state was determined to be 0.59 D from the Stark effects of J=2←1 transitions. The rs coordinates of the OH hydrogen atom have been determined and the orientation of the OH bond in the molecule has been discussed.
Ruthenium Catalyzed Reduction of Nitroarenes and Azaaromatic Compounds Using Formic Acid
Authors: Watanabe Yoshihisa , Ohta Tetsuo , Tsuji Yasushi , Hiyoshi Takao , Tsuji Yasuo
Published: July 2006

Various nitroarenes having chloro, methyl, or methoxy substituents were reduced to the corresponding aminoarenes in high yields using formic acid in the presence of a catalytic amount of RuCl2(PPh3)3. For example, 4-chloronitrobenzene was converted in 99% conversion with 98% selectivity at 125 °C for 5 h. 4-Nitroacetophenone was reduced chemoselectively to 1-(4-nitrophenyl)ethanol in 74% isolated yield under the same reaction conditions. Formic acid could also be employed as reductant for hydrogenation of heterocyclic compounds such as quinoline, indole, and quinoxaline in the presence of the ruthenium catalyst. 2-Methylquinoline was hydrogenated to 1,2,3,4-tetrahydro-2-methylquinoline in 93% conversion with 100% selectivity.
Preferred Conformations of cis-4-Hydroxy-2-chromancarboxylates and Related Compounds. Molecular Force Field Interpretation
Authors: Hirota Minoru , Abe Kazuhisa , Shibata Masamichi , Suezawa Hiroko , Hanaya Kaoru , Muramatsu Takashi , Ikegami Yusaku
Published: July 2006

In contrast to cis-4-hydroxy-2-tetralincarboxylates, cis-4-hydroxy-2-chromancarboxylates take diaxial conformation having 4-pseudoaxial-OH and 2-axial-COOR groups preferably. The preferred conformations of these compounds were rationalized by molecular force field (MM 1/MMP 1) calculations on the corresponding 2-tetralin- and 2-chromancarbaldehydes as model compounds.
N-Hydroxy Amides. II. N-Benzyloxy α-Amino Acid N-Hydroxysuccinimide Esters and Synthesis of a Hexapeptide Having an Alternating N-Hydroxy Amide–Amide Sequence
Authors: Shimizu Kazuyuki , Nakayama Kazuyuki , Akiyama Masayasu
Published: July 2006

Acylation of a series of N-benzyloxy α-amino acid derivatives with N,N-phthaloyloglycine shows that the yield decreases with increasing bulkiness of the substituent even by the acyl chloride or mixed anhydride procedure, and that the use of an excess reagent or a double acylation technique is needed to attain a good yield. The low reactivity of the benzyloxyamino group enables us to utilize N-benzyloxy α-amino acid N-hydroxysuccinimide esters without N-protection in the acylation of the usual amino group. In an attempt to lengthen the chain of an N-hydroxy peptide, a hexapeptide anilide having an N-hydroxy-Dl-alanylglycyl sequence was synthesized via  N-benzyloxy peptides. The complex forming tendency of the hexapeptide with iron(III) is examined.
Stereoelectronic and Homoconjugative Effect of Stereoselectivity. The Addition of Dichlorocarbene to 1,5-Dimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-one and Its Related Compounds
Authors: Nitta Makoto , Okada Shuji , Kato Masami
Published: July 2006

The reaction of dichlorocarbene with 1,5-dimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-one, its corresponding alcohol derivative, and 1,5,8-trimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-endo-ol occurs on the exocyclic double bond to give exo and endo adducts with preferential formation of the exo adduct. Dichlorocarbene addition to 1,3,5-trimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-one (1d) occurs on the endocyclic double bond from the exo side, while the reaction occurs on the exocyclic double bond from both the exo and endo sides in the case of the corresponding alcohol derivative. The stereoselectivity or site selectivity was discussed on the basis of the stereoelectronic and homoconjugative effects as well as the steric effect of the reaction. Several chemical transformations, along with the derivation of bis adducts of dichlorocarbene, were also studied for confirmation of the structure of mono adducts. 1,3-Dipolar cycloaddition of 1d and its dichlorocarbene adduct with mesitonitrile oxide, giving the adducts on the exocyclic double bond, was also studied to suggest a possible causative factor to control the electrophilic addition in the indicated direction.
A New Wittig Rearrangement of 2,2-Disubstituted 1,3-Dithianes
Authors: Ikehira Hideyuki , Tanimoto Shigeo
Published: July 2006

Carbanions produced by deprotonation at the ring C-4 of 2,2-disubstituted 1,3-dithianes undergo a Wittig type rearrangement to give the anions of 2,2-disubstituted tetrahydrothiophene-3-thiols. After being trapped with several alkyl halides, these afford the corresponding 2,2-disubstituted 3-(alkylthio)tetrahydrothiophenes, which are difficult to prepare by other synthetic routes.
Constituents of Seeds of Ailanthus altissima Swingle. Isolation and Structures of Shinjuglycosides A, B, C, and D
Authors: Yoshimura Shin , Ishibashi Masami , Tsuyuki Takahiko , Takahashi Takeyoshi , Matsushita Kazuhiro
Published: July 2006

Four bitter quassinoid glycosides, shinjuglycosides A, B, C, and D were isolated from seeds of Ailanthus altissima  Swingle and their structures were established to be 2-β-d-glucopyranosides of chaparrin, shinjulactone A, amarolide 11-acetate, and amarolide, respectively, from spectral data and enzymatic or acid-catalyzed hydrolysis.
The Reaction of Primary Nitro Compounds with Dipolarophiles in the Presence of p-Toluenesulfonic Acid
Authors: Shimizu Tomio , Hayashi Yoshiyuki , Teramura Kazuhiro
Published: July 2006

3-Substituted 2-isoxazolines or isoxazoles were obtained from the reaction of primary nitro compounds [methyl nitroacetate, 2-nitro-1-phenylethanone, (nitromethyl)benzene, 1-nitropropane, and (phenylsulfonyl)nitromethane] with dipolarophiles in refluxing mesitylene in the presence of a small amount of p-toluenesulfonic acid. The formation of these products can be explained in terms of 1,3-dipolar cycloaddition of nitrile oxide generated by a dehydration of the primary nitro compounds. On the other hand, 4,5-decamethylene-3-phenylsulfonyl-2-isoxazoline N-oxide was obtained from a similar reaction of (phenylsulfonyl)nitromethane with cyclododecene. The formation of the isoxazoline N-oxide can be explained on the basis of the intermediacy of 3,4-bis(phenylsulfonyl)furazan 2-oxide.
Hydrogenation and Hydrogenolysis. XVII. The Selectivities of Platinum Group Metals in Catalytic Hydrogenation of 2-Naphthol and Tetrahydro-2-naphthols
Authors: Nishimura Shigeo , Ohbuchi Shin-ichi , Ikeno Kiyoshi , Okada Yasuhiro
Published: July 2006

Catalytic hydrogenation of 2-naphthol (NL) with the six platinum metals has been studied in t-BuOH at 80 °C and 4–5 MPa H2 pressure. Selectivities for formation of 1,2,3,- and 5,6,7,8-tetrahydro-2-naphthols (ac- and ar-TLs) have been determined by application of a kinetic equation. ar-TL was formed more predominantly than ac-TL over all the metals. The hydrogenation of ac- and ar-TLs has also been studied under the same conditions for comparison. The hydrogenation of NL and ar-TL was accompanied by extensive hydrogenolysis to give decalins over Os, Ir, and Pt, whereas the hydrogenolysis occurred only slightly over Ru, Rh, and Pd. In general the hydrogenolysis occurred to much lesser extents with ac-TL. The amounts of 2-decalone formed in hydrogenation of ar-TL have been determined by application of the kinetic equation. The 2-decalone was the cis isomer only except with Pd. For formation of the cis products at the ring juncture, hydrogenation of ar-TL was highly stereoselective with Ru, Rh, Os, and Ir, while hydrogenation of ac-TL was the most stereoselective with Os and Ir. The course of hydrogenolysis and the stereochemistry of hydrogenation are discussed from the comparative results on NL, ar-TL, and ac-TL.
The Viscosity Coefficients of 18-Crown-6–Alkali Metal-ion Complexes
Authors: Kawaizumi Fumio , Yajima Isao , Nomura Hiroyasu , Miyahara Yutaka
Published: July 2006

The viscosities of LiCl, KCl, and CsCl have been measured in water and aqueous solutions containing 0.398 mol/dm3 of 18-crown-6 (CR) at 25 °C. The B-coefficients of the alkali metal chlorides in water have been obtained using the theoretical values of the A-coefficients. The viscosity coefficients of 18-crown-6 itself have been determined in water and methanol. In systems containing crown ether, the viscosity increment due to the complex formed in solutions, Δη[CR–M+]Cl−, has been evaluated by subtracting from the observed viscosity the increment attributed to non-coordinated crown ether and alkali metal chlorides in solutions. The two complex ions, [CR-K+] and [CR-Cs+], have nearly the same values of the B-coefficients, and these values are, in turn, approximately equal to that of 18-crown-6 in water. Measurements done on KCl in methanol containing 18-crown-6 have led to the finding that in methanol, 18-cown-6 and the [CR-K+] ion take effectively the same B-value.
The Structure of Liquid Alcohols by Neutron Diffraction. II. Molecular Structure of Ethyl Alcohol
Authors: Tanaka Yukio , Ohtomo Norio , Arakawa Kiyoshi
Published: July 2006

The structure factor Sm(Q) for liquid ethyl alcohol (C2D5OD) at room temperature was obtained by means of the time-of-flight (TOF) neutron diffraction method using electron LINAC. An analysis of the diffraction data was carried out and the molecular structure in liquid phase was determined as follows: the O–D,C–O, and C–C bond lengths are 0.960±0.010 Å, 1.410±0.010 Å and 1.510±0.010 Å, respectively.
The Structure of the Cyclodextrin Complex. XVII. Crystal Structure of β-Cyclodextrin–Hexamethylenetetramine (1:1) Complex Hexahydrate
Authors: Harata Kazuaki
Published: July 2006

The crystal structure of β-cyclodextrin–hexamethylenetetramine (1:1) complex hexahydrate was determined by the X-ray diffraction method. The crystal ismonoclinic with the space group P21, Z=2, a=15.285(3), b=10.345(2), c=20.118(2) Å, and β=102.14(1)°. The structure was solved by inspection of a Patterson map and the trial-and-error method combined with the rigid-body least-squares technique and refined by the block-diagonal least-squares method to the R-value of 0.056 for 4369 reflections (sinθ⁄λ<0.55). The β-cyclodextrin molecule is slightly distorted from the regular heptagonal structure. The orientation of two primary hydroxyl groups is statistically disordered. The secondary hydroxyl groups form intramolecular hydrogen bonds between adjacent glucose residues. The guest hexamethylenetetramine molecule, being located roughly at the center of the β-cyclodextrin ring, is in van der Waals contact with the interior surface of the host molecule. Two out of four nitrogen atoms of hexamethylenetetramine form N···H–O hydrogen bonds with water and adjacent β-cyclodextrin molecules. β-Cyclodextrin molecules are stacked along the crystallographic b axis, with which the plane through seven glycosidic oxygen atoms makes an angle of 46.7°, forming a “cage-type” packing. Water molecules occupy the intermolecular spaces between β-cyclodextrin molecules.
Temperature Dependence of Magnetic Susceptibilities of (TTT)(TCNQ) and (TTT)(TCNQ)2
Authors: Takahashi Masashi , Sugano Tadashi , Kinoshita Minoru
Published: July 2006

Static magnetic susceptibility and ESR studies of 1:1 and 1:2 charge-transfer complexes of naphthaceno-[5,6-cd:11,12-c′d′]bis[1,2]dithiole and 2,2′-(2,5-cyclohexadiene-1,4-diylidene)bis(propanedinitrile) [(TTT)(TCNQ) and (TTT)(TCNQ)2] in the temperature region of 2–310 K are described. (TTT)(TCNQ)2 exhibits a temperature dependent spin susceptibility, while the spin susceptibility of (TTT)(TCNQ) is almost independent of temperature. Spin susceptibilities of the TTT and TCNQ chains, which are evaluated with a g-value decomposition technique, are interpreted in terms of a one-dimensional Hubbard model. In both complexes, the on-site Coulomb repulsion is comparable with or larger than the band width on the TCNQ chains and is smaller on the TTT chains. Two magnetic phase transitions are observed in (TTT)(TCNQ)2. The transition is driven in each chain independently by the Peierls instability. The amount of charge transfer in (TTT)(TCNQ) is determined to be 0.73±0.05 from an X-ray photoelectron spectroscopic study.
An X-Ray Diffraction Study on the Structures of Mono(glycinato)copper(II) and Tris(glycinato)cuprate(II) Complexes in Aqueous Solution
Authors: Ozutsumi Kazuhiko , Ohtaki Hitoshi
Published: July 2006

The structures of mono(glycinato)copper(II) and tris(glycinato)cuprate(II) complexes in solution were determined by means of X-ray diffraction at 20 °C. The radial distribution curve obtained for solution A, in which comparable amounts of hexaaqua- and mono(glycinato)copper(II) complexes coexisted (the mole ratio Cgly⁄CCu=0.700, where Ci represents the total concentration of species i), showed that the mono(glycinato)copper(II) complex combined with four water molecules, two of which were at the distance of (1.98±0.01) Å at the equatorial position and the other two were of (2.27±0.01) Å at the axial one. The equatorial Cu–OH2 bond length within the mono(glycinato)copper(II) was longer than that within the hexaaquacopper(II) ion (1.94 Å), whereas the axial Cu–OH2 bond distance within the former complex was shorter than that within the latter (2.43 Å). Both lengths of the Cu–O and Cu–N bonds within the mono(glycinato)copper(II) ion were (1.99±0.02) Å. Thus the [Cu(gly)(OH2)4]+ complex has an axially elongated octahedral structure. The X-ray scattering data of solution B with the Cgly⁄CCu mole ratio of 13.7, in which almost all Cu(II) ions formed the tris(glycinato)cuprate(II) complex were well explained in terms of a regular octahedral structure of the complex having the same Cu–O and Cu–N bond distances of (2.02±0.01) Å. The structure of the bis(glycinato)copper(II) complex was not determinable owing to its low solubility.
Crystal Structures and Characterization of Cobalt(II), Manganese(II), and Zinc(II) Complexes of 2-[Bis(2-benzimidazolylmethyl)amino]ethanol
Authors: Takahashi Kazuhiro , Nishida Yuzo , Kida Sigeo
Published: July 2006

Cobalt(II), manganese(II), and zinc(II) complexes with the tripodal ligand, 2-[Bis(2-benzimidazolylmethyl)amino]ethanol, bbt, were prepared and characterized by infrared and electronic spectra, magnetism, and conductivities. Their crystal structures were determined by X-ray diffraction method. Crystal data: [Co(bbt)(NCS)2] (1), space group P212121(orthorhombic), a=12.881(1), b=17.970(2), c=9.076(1) Å; [Mn(bbt)(NCS)2](2), space group P212121(orthorhombic), a=18.179(2), b=13.073(2), c=9.097(2) Å; [Zn(bbt)(NCS)2](3), space group P21/ a(monoclinic), a=15.421(4), b=14.803(4), c=10.589(3) Å, β=115.81(2)°. The final R values are 0.044 (1), 0.054 (2), and 0.079 (3), for non-hydrogen atoms. The coordination geometries of 1 and 2 can be described as a distorted octahedron. In 3, the alcoholic oxygen of bbt is not in coordination, hence the zinc ion is five-coordinated forming a highly distorted trigonal bipyramid. In all the complexes, thiocyanate ions coordinate in cis form with the nitrogen atoms. The magnetic measurements revealed that 1 and 2 are high spin complexes.
The Thermal Decomposition of CF3I in Ar
Authors: Saito Ko , Yoneda Yuji , Tahara Hiroyuki , Kidoguchi Sadao , Murakami Ichiro
Published: July 2006

The thermal decomposition of CF3I behind reflected shock waves was studied by means of the UV absorption over the temperature range of 935–1235 K and in the density range of 6.3×10−6–3.8×10−6 mol cm−3. The decomposition rate was in the fall-off region, and the main process was the C-I bond fission. The rate constants corresponding to the limiting high- and low-pressure regions were determined to be;

k ∞=1014.67exp(−27200⁄T)s−1

and;

k 0⁄[Ar]=1014.71exp(−15000⁄T)cm3mol−1s−1.
Hydrates of Organic Compound IX. Enclathration of Methyl and Ethyl Alcohols within the Water Lattice of Tetrahydrofuran Clathrate Hydrate
Authors: Matsui Hiroshi , Nakayama Haruo
Published: July 2006

The amount of methyl or ethyl alcohol existing in a hydrate solid deposited from ternary mixtures of methyl (or ethyl) alcohol-tetrahydrofuran–water has been determined using 14C-labeled alcohols. It was found that these alcohols could be enclathrated within the water lattice of tetrahydrofuran clathrate hydrate.
Primary Structure and Molecular Evolution of Protein. Internal Homology and Intramolecular Evolutionary Tree of Calmodulin
Authors: Iida Yôichi
Published: July 2006

One notable feature of the primary structure of calmodulin is its internal homology. It can be subdivided into four domains having a similar amino acid sequence. In the present paper, an intramolecular evolutionary tree was constructed with the four domains. The origin and evolution of calmodulin was discussed on the basis of these results.
Studies on Lactams. VII. Conformation of d-Glucono-1,5-lactam
Authors: Ogura Haruo , Furuhata Kimio , Takayanagi Hiroaki , Tsuzuno Nobuyasu , Iitaka Yoichi
Published: July 2006

The structure of d-glucono-lactam (5-amino-5-deoxy-d-glucono-lactam) has been established by means of X-ray crystal structure analysis. The stereochemistry of d-glucono-lactam in crystal was determined to be a half-chair conformation.
Internal Heavy Atom Effects on the Exciplex Fluorescence: Anthracene–N,N-Dimethylaniline System
Authors: Hamai Sanyo
Published: July 2006

Intrinsic fluorescence yields of exciplexes, φf0, have been determined for halogenated systems of anthracene (A)–N,N-dimethylaniline (DMA) in cyclohexane. By the substitution of a chlorine atom for a hydrogen atom in either A or DMA, φf0 is reduced to about 1/5, whereas by the bromine substitution it is reduced to about 1/80. When more than one halogen atom of the same kind are substituted in the A–DMA exciplex, the first substitution causes more prominent reduction in φf0 than the subsequent substitution does. Although there is a remarkable irregularity in the fluorescence quantum yields of halogenated anthracenes which were used as the electron acceptors in the exciplexes, φf0 varies regularly according to the kind and the number of the halogen substitutions. The internal heavy atom effect on φf0 is explained by the enhancement of the intersystem crossing rate to the triplet state.
Stopped-flow Kinetic Studies of Cu2+ Ion Binding to Bovine Serum Albumin
Authors: Kure Naohisa , Nakatsuji Hitoshi , Sano Takayuki , Yasunaga Tatsuya
Published: July 2006

The interaction of Cu2+ ion with bovine serum albumin (BSA) was studied statically by equilibrium dialysis and ultraviolet spectrophotometric titration techniques, and kinetically by the stopped-flow method with transmittance detection at 255 nm. The static measurements showed the presence of one primary binding site and a number of weaker binding sites at pH 5.2. Stopped-flow measurements were undertaken in the pH region of 4–6.4 where a single reaction process was observed on the order of several seconds following the rapid absorbance change within the dead-time of the apparatus. This single reaction process was attributed to reaction of Cu2+ ion with the primary BSA site. The analyses of pH and concentration dependences of both the relaxation time and absorbance change confirmed the presence of two types of bound Cu2+ species to the primary binding site. One type formed during the dead-time of the apparatus is postulated as a square-planar complex formed between Cu2+ and the three N-terminal peptides of BSA. This reaction occurs with Cu2+ being exchanged for hydrogen ions on the N-terminal peptides. The second type of bound Cu2+, observed by stopped-flow method is thought to result from a bimolecular binding of Cu2+ ion a deprotonated imidazolyl group in the third position of the histidyl residue; the value of the molar extinction coefficient for this species, determined kinetically, suggests a further coordination of the β-carboxyl group to the bound Cu2+.