bluuebunny/crossref_metadata_2025 huggingface dataset:
Solid Phase Peptide Synthesis by Oxidation-Reduction Condensation. Synthesis of Adrenocorticotropin(1–24) by Chain Elongation at the Carboxyl End on Solid Support
Authors: Maruyama Hiroshi , Matsueda Rei , Kitazawa Eiichi , Takahagi Hidekuni , Mukaiyama Teruaki
Published: July 2006

Solid phase peptide synthesis by oxidation-reduction condensation via fragment condensation at the carboxyl end was established by a new monitoring method based on high pressure liquid chromatography. The merit of the method was demonstrated through the synthesis of ACTH (1–24). A resin–tetracosapeptide with quantitative amino acid ratios was easily prepared by coupling 6 fragments of 1–2, 3–7, 8–10, 11–14, 15–19, and 20–24 sequences. ACTH (1–24) with a full activity was obtained in 25% yield from the initial resin-dipeptide by hydrogen fluoride treatment and purification with carboxymethyl-cellulose chromatography.
The Kinetics of the Reaction between the Chromium(III) Ion and the Ethylenediamine-N,N,N′,N′-tetraacetate Ion in the Presence of Hydrogen Peroxide
Authors: Yamamoto Katsumi , Ohashi Kousaburo
Published: July 2006

The rate of the reaction between chromium(III) ion and ethylenediamine-N,N,N′,N′-tetraacetate was found to be accelerated upon the addition of a large excess of hydrogen peroxide. Under such a condition the rate of CrIII(edta)(H2O)− formation shows a first-order dependence on the concentrations of hydrogen peroxide and chromium(III) ions, but is independent of the concentration of EDTA. The rate of CrIII(edta)(H2O)− formation catalyzed by the hydrogen peroxide increases with an increase in the pH and decreases with an increase in the acetate ion concentration. The kinetic study suggested that the initiation of the reaction takes place as follows: Cr(III)+H2O2→Cr(IV)+OH·+OH− The reaction mechanism of the hydrogen-peroxide catalysis is discussed in terms of the formation of the chromium(IV)– and /or the chronium(V)–EDTA complex in the course of the reaction. It was found that monohydroxochromium(III) is much more reactive than the chromium(III) ion toward hydrogen peroxide.
The Mechanism of the Hydrolysis of Condensed Phosphates. IV. The Hydrolysis of Pyro-, Tripoly-, Trimeta-, and Tetrametaphosphates in Aqueous Organic Solvents
Authors: Watanabe Makoto , Sato Shoji , Saito Hajime
Published: July 2006

The hydrolysis of sodium pyro-, tripoly-, trimeta-, and tetrametaphosphates was run in water, aqueous ethanol, aqueous glycerol, aqueous acetonitrile, aqueous dimethyl sulfoxide, and aqueous tetrahydrofuran at various pH values and temperatures. The initial concentration of the phosphates was 0.025 mol/l. The hydrolysis of the poly- and metaphosphates followed first-order kinetics with respect to the concentration of the phosphate, under all conditions studied. The hydrolysis of sodium pyro- and tripolyphosphates was an acid-catalyzed reaction and that of sodium trimeta- and tetrametaphosphates was an acid- and base-catalyzed reaction. In acidic solutions, the rate of hydrolysis of the poly- and metaphosphates in water was slower than that in any aqueous organic solution. It is concluded that the nucleophilicity of the water molecule in the aqueous organic solutions may increase on account of the interaction of the water molecule with the organic molecules. The hydrolysis of sodium pyro-, tripoly-, trimeta-, and tetrametaphosphates in acidic solutions is considered to be of the SN2 type, because the overall-reaction rate is highly dependent on the nucleophilicity of the water molecule. The solvent effect on the rate of hydrolysis of sodium tripolyphosphate in basic solutions was the same as that in acidic solutions and hence the mechanism of the hydrolysis of sodium tripolyphosphate in basic solutions may be the same as that in acidic solutions. The rate of hydrolysis of sodium trimeta- and tetrametaphosphates in a basic water solvent was much faster than that in basic aqueous ethanol and basic aqueous dimethyl sulfoxide and was largely slower than that in basic aqueous glycerol. Consequently, the mechanism of the hydrolysis of sodium trimeta- and tetrametaphosphates in basic solutions seems to differ from that in acidic solutions. The acceleration of the rate of hydrolysis of the metaphosphates by the organic molecules depends significantly upon the activation energy. The activation energy of the hydrolysis of sodium pyro-, tripoly-, trimeta-, and tetrametaphosphates was 17–34 kcal/mol in the pH range of 1.0–12.2 and increased with an increase in the pH value of the phosphate solution in water and aqueous ethyl alcohol solventss.
Studies on Leuckart-Wallach Reaction Paths
Authors: Ito Keiichi , Oba Hitoshi , Sekiya Minoru
Published: July 2006

The Leuckart-Wallach reaction paths were investigated by means of catalytic reduction in the Leuckart-Wallach reaction system and on the basis of analogous formic acid reductions. It was determined that, in the early stage of the Leuckart-Wallach reaction, ammonia, amine and also formamide undergo addition reactions to carbonyl compounds. The addition of formamide catalyzed by formic acid plays a significant role only for the more reactive substrates such as benzaldehyde. The behaviors of plausible intermediates for the formic acid reduction are discussed on the basis of the data of similar formic acid reductions.
Synthesis of 2,7-Di-t-butyl-4,5,9,10-tetraphenyltricyclo[6.2.0.03,6]deca-1,3(6),4,7,9-pentaene. A Benzo[1,2: 4,5]dicyclobutene
Authors: Toda Fumio , Takahara Yutaka
Published: July 2006

The title compound (15) which has two cyclobutadienes fused to a benzene ring, was synthesized by heating dl- (7), meso-3,8-di-t-butyl-1,5,6,10-tetraphenyldeca-3,4,6,7-tetraene-1,9-diyne (8), or E,Z,-3,4-bis (1-t-butyl-3-phenyl-2-propynylidene)-1,2-diphenyl-1-cyclobutene (12).
Synthesis and Properties of Organocobalt(III)octaethylporphyrins
Authors: Ogoshi Hisanobu , Watanabe Ei-ichi , Koketsu Norihisa , Yoshida Zen-ichi
Published: July 2006

The syntheses of alkylcobalt(III)octaethylporphyrins(OEP) via nucleophilic attack of the Co(I) complex to unsaturated compounds are reported. Olefins with an electron-withdrawing group and acetylenes react with Co(I)(OEP), whereas olefins with an electron-donating group such as propylene and cyclohexene are unreactive. A novel ring cleavage of cyclopropyl methy ketone initiated by Co(I)(OEP) affords alkylCo(III)(OEP). The reduction of cobalt(II) N-methyloctaethylporphyrin acetate results in intramolecular methyl migration from nitrogen to the central cobalt atom. Five-coordination has been established for the organocobalt(III)(OEP) complexes on the basis of their analytical, infrared and NMR data. Some anomalous behavior of the proton signals of the α-carbon atom in their NMR spectra has been discussed in terms of quadrupolar relaxation and electronegativity of the cobalt ion.
Reactions of Dihydridotetrakis(triphenylphosphine)ruthenium(II) with Olefins and Isolation of New Ruthenium–Olefin Complexes
Authors: Komiya Sanshiro , Yamamoto Akio
Published: July 2006

Dihydridotetrakis(triphenylphosphine)ruthenium(II), RuH2(PPh3)4, reacts with olefins (ethylene, propylene, styrene and butadiene) to give olefin-coordinated complexes of the type, Ru(olefin)(PPh3)3 and equimolar amounts of their hydrogenation products per mol of the dihydride complex. The olefin coordinated with ruthenium can be exchanged with other olefins. Olefin-coordinated complexes easily react with molecular hydrogen to afford tetrahydridotris(triphenylphosphine)ruthenium, RuH4(PPh3)3, releasing alkane at room temperature. Under hydrogen atmosphere, catalytic hydrogenation of the olefins smoothly takes place with RuH2(PPh3)4. (Ethylene) tris(triphenylphosphine) ruthenium (0) reacts with methyl iodide to give propylene and a trace of bu adiere along with methane, ethylene, and small amounts of ethane and butenes. The formation of propylene suggests that oxidative addition involving cleavage of the C–H bond of ethylene to ruthenium giving a hydridovinyl complex may be taking place. Reactions of Ru(C2H4)(PPh3)3 with methyl-d3 iodide and ethyl iodide, and of Ru(C3H6)(PPh3)3 with methyl iodide were examined to test the generality of this type of reaction. The reaction of Ru(C2H4)(PPh3)3 with CD3I released CD4 and CD2H2 together with CD3H suggesting the involvement of α-hydrogen abstraction.
Organic Photochemical Reactions. XXIV. Photocycloaddition of Propanal to 1,3-Cyclohexadiene
Authors: Shima Kensuke , Kubota Tadatoshi , Sakurai Hiroshi
Published: July 2006

The photocycloaddition of propanal to 1,3-cyclohexadiene leads to oxetanes, as well as to the dimers of 1,3-cyclohexadiene. A mechanism of oxetane formation is proposed in which singlet excited propanal attacks a ground-state 1,3-cyclohexadiene to give a singlet complex with a charge-transfer character. The complex either decays to the ground-state reactants or reacts to give oxetanes. Quantum yield measurements and kinetic analysis show a rate constant of 4×109 M−1 s−1 for singlet complex formation from propanal and 1,3-cyclohexadiene in benzene. The quenching data of propanal fluorescence support such a mechanism.
The Photochemical Reaction of 2-Alkoxy-1,4-naphthoquinones with Olefins. III. The Re-examination of the Structures of the Photo-addition Compounds and the Reaction Mechanism
Authors: Otsuki Tetsuo
Published: July 2006

In the photochemical reaction of 2-alkoxy-l,4-naphthoquinones with a variety of olefins, two types of photoaddition compounds are found to be produced: the cyclobutane-ring compounds and the oxetanol-ring compounds. Although the present author has assigned the structure of a tetrahydropyran-ring compound to one of the photoaddition compounds primarily on the basis of the analyses of the spectral data, the previously proposed structures should be corrected to an oxetanol-ring compound on the basis of the chemical reactivities. Although some cyclobutane-ring compounds were stable enough to be isolated as final reaction products, the other cyclobutane-ring compounds, though once produced, were too unstable to undergo the subsequent photochemical reaction to give oxetanol-ring compounds on further irradiation. The stability of the cyclobutane-ring compounds was dependent on both the substituents of the olefins and the wavelength of the light. The origin of the stability and the reaction mechanism were investigated.
Concentration Fluctuation and the Light-scattering Spectrum
Authors: Iwasaki Kenji , Tanaka Masami , Fujiyama Tsunetake
Published: July 2006

Light-scattering spectra were observed for binary solutions of carbon disulfide–chloroform at various concentrations. The relation between the Rayleigh-line intensity and the concentration fluctuation was derived. Using the proposed relation and the observed Rayleigh intensity, the concentration dependence of the concentration fluctuation was then determined. The results suggest that chloroform and carbon disulfide molecules have a tendency to get together in the binary solution.
Solvent Effects on the ESR Spectra of Copper(II) Complexes. A Consideration of the Donicity of Water and Methanol
Authors: Ogata Tateaki , Fujisawa Tadashi , Tanaka Nobuyuki , Yokoi Hiroshi
Published: July 2006

Solvent effects on the ESR spectra of bis(2,6-dimethyl-3,5-heptanedionato)copper(II) ([Cu(dibm)2]) and a similar copper(II) complex were investigated in some detail. A clear relationship between the ESR parameters and the donicity of the solvents was confirmed, and this is discussed with the intention of investigating the donicities of water and methanol. The donor number for water in an aqueous solution was estimated to be about 30 from a precise analysis of the ESR spectra of [Cu(dibm)2] in water–methanol mixtures.
Carboxylation of Phenol Derivatives. XXII. Formation of Alkali Alkyl Carbonate by the O-Carboxylation of Alcohol in the Presence of an Alkali Salt of a Weak Acid
Authors: Hirao Ichiro , Kito Taketoshi , Funamoto Takatomo , Murakami Taketoshi , Usami Katsuyuki
Published: July 2006

O-Carboxylation of the alcohol (ROH) occurred to give alkali alkyl carbonate in a good yield when carbon dioxide was introduced into the mixture of an alkali salt of a weak acid, alcohol, and acetone (or THF) at room temperature under atmospheric pressure. Such alkali salts as PhOM, p-R′C6H4OM (R′=CH3, CH3O, or Br), Et2NCSSM, NaCN, and C6H4(CO)2NK (M=K or Na) were effective. The mixture of HOC6H4COOM and ROCOOM was obtained from the reaction using MOC6H4COOM as an alkali salt. However, the mixture was composed of equimolar amounts of p-HOC6H4COOM and ROCOOM when p-MOC6H4COOM was used. In this reaction, two mechanisms have been examined.
The Reaction of Monoketones with Manganese(III) Acetate
Authors: Okano Masayoshi , Aratani Takaaki
Published: July 2006

When acetone, ethyl methyl ketone (EMK), and cyclohexanone were heated with manganese(III) acetate dihydrate in a mixed solvent of glacial acetic acid and acetic anhydride at 100 °C, acetoxy ketones were obtained as common products. Furthermore, ketone dimers (1,4-diketones) were obtained from acetone and cyclohexanone, which also gave 1,2,3,4-tetrahydrodibenzofuran. When mixtures of these ketones and 1-hexene were heated with the oxidant, saturated and unsaturated ketones and γ-acetoxy ketones were obtained as common products, and 2-propylchromene was obtained as a new product from the cyclohexanone-1-hexene mixture. The formation courses of these reaction products are discussed.
Formation of Diorganostannylenes. I. Photolytic Reaction of Dibutyltin with Organic Halides
Authors: Kozima Sinpei , Kobayashi Kazuhiko , Kawanisi Mituyosi
Published: July 2006

The photochemical reactions of dibutyltin, (Bu2Sn)m, with alkyl monohalides, R′X, give Bu2R′SnX-type compounds by the insertion of the intermediately formed dibutylstannylene to the C–X bond of alkyl halides. This provides a facile method for preparing Bu2R′SnX compounds, since the reaction proceeds quickly under mild conditions giving the products in good yields, the only by-product Bu3SnX which can be distilled being obtained only in a low yield. The reactions with dihalomethanes were also successful. The reaction pathway is discussed in connection with the reactivities of the substrates.
The Synthesis of Benzannelated Annulenes. Dibenzo-tetrakisdehydro[18]annulene, and Tribenzo-bisdehydro[14]annulene
Authors: Ojima J\={u}ro , Yokomachi Tadayoshi , Kimura Akihiko
Published: July 2006

In order to establish the effect of the annelation of benzene rings on [4n+2] annulenes, the syntheses of benzannelated dehydroannulenes were attempted. Dibenzo-tetrakisdehydro[ 18]annulenes (IIa and IIb) were prepared according to the reaction sequence developed in the synthesis of tetramethyltetrakisdehydro[18]annulene (I) from o-ethynylbenzaldehyde (VIII); both of them proved to be unstable. Tribenzo-bisdehydro[14]annulene (XVII) was also prepared from VIII by a double Wittig reaction, followed by oxidative coupling. An examination of the NMR spectrum indicated that XVII is atropic.
Absorption Spectra of Four Naphthalenediols with C2V Symmetry. Interpretation by Means of Configuration Analysis
Authors: Fujii Tsuneo , Suzuki Satoshi
Published: July 2006

The electronic absorption spectra of four substituted naphthalenes with two electron-donating groups, 1,4-, 1,8-, 2,3-, and 2,7-naphthalenediols, have been investigated by means of configuration analysis, with particular attention paid to the dependence of the spectra on the positions of substitutions and on the molecular symmetry. The wave functions calculated by the Pariser-Parr-Pople method are analyzed in terms of locally-excited states and intramolecular charge-transfer states. The excited electronic wave functions of naphthalenediols have been expanded not only in terms of the electronic states of naphthalene, but also in terms of those of naphthol. The present configuration analysis shows that the electronic states of all these four naphthalenediols may reasonably interpreted in terms of locally-excited states of the parent compounds and charge-transfer states from the substituents to the parent compounds. The characteristic spectral changes in the Lb, La, and Bb bands caused by substitution are adequately explained in relation to the positions and to the molecular symmetry. The intensification of the Lb band caused by the introduction of the hydroxyl groups is interpreted as due to the mixing between the Lb and Bb bands. The Bb reference state interacts with the Lb and Ag− reference states in 1,4- and 2,3-naphthalenediols, whereas it interacts with the Lb, B1g+, and B1g− reference states in 1,8- and 2,7-naphthalenediols.
X-Ray Photoelectron Spectroscopy of Chloromethanes and Chloroethanes
Authors: Ohta Toshiaki , Kuroda Haruo
Published: July 2006

X-Ray photoelectron spectra of chloromethanes (CH4−nCln, n=2,3,4) and chloroethanes (CH3CH3−nCln, n=1,2,3) in vapor phase were observed employing Mg Kα radiation. The observed Cls binding energies were analyzed by means of Siegbahn’s electrostatic potential model and charge densities calculated by the CNDO/2 method, and the effects of inclusion and exclusion of Cl 3d atomic orbitals in the basis set of the CNDO/2 calculation is critically investigated. The assignment of all valence electron levels of above molecules were performed with the aids of the CNDO/2 calculations incorporated with Gelius’ intensity model and the reported data of ultraviolet photoelectron spectroscopy.
Dehydroannulenes. III. Synthesis and Properties of 1,5,10,14-Tetra-tert-butyl-6,8,15,17-tetrakisdehydro[18]annulene
Authors: Tomita Sachiyo , Nakagawa Masazumi
Published: July 2006

In order to find out substituent groups which provide stability and solubility to tetrakisdehydro[18]annulene system without appreciable electronic interaction with the annulene ring, the synthesis of 1,5,10,14-tetra-tert-butyl-6,8,15,17-tetrakisdehydro[18]annulene (VIII) has been catrried out starting from 3-tert-butyl-2-penten-4-ynal (III). It was found that the tetra-tert-butyl derivative (VIII) is strongly diatropic, and more stable and much more soluble than tetramethyl-, dimethyl-, diphenyl-, and tetraphenyl-analogues. The electronic spectrum of tetra-tert-butyl derivative (VIII) was found to be closely related with that of tetramethyltetrakisdehydro[18]annulene indicating a minor electronic perturbation of tert-butyl groups on the annulene ring.
The Conformations of Copper(II) Complexes with edda-Type Optically Active Polyamino Carboxylic Acids in Aqueous Solutions
Authors: Murakami Tasuku , Hatano Masahiro
Published: July 2006

A copper(II) complex with (S,S)-1,1′-ethylenedipyrrolidine-2,2′-dicarboxylic acid (H2epro) was prepared, and its absorption and CD spectra were measured in an aqueous solution. A weak absorption band at 9500 cm−1 was indicative of the apical coordination of the carboxylate group. Furthermore, from the fact that the effect of unidentate bases, such as pyridine and ammonia, on the absorption and CD spectra of the epro complex was quite different from that of bidentate bases, the epro complex was expected to take a Λ-uns-cis conformation. In addition, the base-addition effect was measured for the complexes of (S,S)-α,α′-dimethyl-N,N′-ethylenediaminediacetic acid(H2eddp), (S,S)-α,α′-diisopropyl-N,N′-ethylenediaininediacetic acid(H2eddv), and (S,S)-α,α′-dibenzy-N,N′-ethylenediaminediacetic acid(H2eddc). The conformations of these complexes are also discussed on the basis of the information obtained for the epro complex.
The Crystal Structure of Bis[1-(2-thiazolylazo)-2-naphtholato]cobalt(III) Perchlorate
Authors: Kurahashi Masayasu
Published: July 2006

The crystal structure of bis[1-(2-thiazolylazo)-2-naphtholato]cobalt(III) perchlorate, [CoIII(C13H8N3OS)2]ClO4 was determined from X-ray reflection data collected by counter methods. The crystals are monoclinic, space group P21/c, with a=10.348(2), b=21.066(5), c=13.072(5) Å, β=112.35(3)°, and Z=4. The structure was determined by the heavy-atom method and refined by the least-squares technique to give an R value of 0.051 for 2696 observed reflections. The cobalt atom is six-coordinate and exhibits octahedral coordination. The 1-(2-thiazolylazo)-2-naphtholato group is coordinated as a terdentate ligand with the cobalt atom through the phenolic oxygen atom, the azo nitrogen atom adjacent to the naphthol ring and the thiazole nitrogen atom giving two five-membered chelate rings. Short intraligand contacts of 2.24(6) and 2.28(6) Å are observed between the azo nitrogen and naphthol hydrogen atoms.
Reactions of 2-Guanidino-1-cyclohexanol with Ketals and Acetals
Authors: Takagi Yasushi , Kawashima Osamu , Tsuchiya Tsutomu , Sano Hiroshi , Umezawa Sumio
Published: July 2006

Reactions of 2-guanidino-1-cyclohexanols (1, 1d, 1l) with 1,1-dimethoxycyclohexane in N,N-dimethylformamide in the presence of p-toluenesulfonic acid gave the N,O-cyclohexylidene derivatives (5, 5d, 5l), respectively. Similar reactions of 1l with 2,2-dimethoxypropane and with dimethyl acetals of p-tolualdehyde and p-bromobenzaldehyde also gave an N,O-isopropylindene, N,O-(p-methylbenzylidene) and N,O-(p-brornobenzylidene) derivative (8l, 9l, 10l), respectively. From IR and PMR spectral studies of 9l  p-toluenesulfonate, seven-membered structures as exemplified by 9A were assigned. The N,O-blocked derivatives (5,9) are stable in weakly acidic or alkaline media, but in stronger media, they are cleaved to 1. The usefulness of the protective groups was also examined. 9 was found to resist tosylation or mesylation in pyridine but not acylation. The numerical values of optical rotations of the guanidinocyclohexanols were greatly enhanced by N, O-blocking.
Chemical Correlations of α-Santonin with (+)-Junenol and Acolamone
Authors: Niwa Masatake , Iguchi Masanobu , Yamamura Shosuke
Published: July 2006

The chemical transformation of the acetoxy ketone (5), which has previously been obtained from α-santonin, to (+)-junenol (1) and acolamone (3) has been carried out. In addition, isojunenol (2) was also derived from 5  via the trisubstituted olefin (9) which was obtained as the main product from the α- and β-oriented mesylates (8 and 11) on treatment with NaI in HMPA.
Influence of Anhydrous Hydrogen Fluoride on Hen Egg-White Lysozyme. II. Effects on Reduced Hen Egg-White Lysozyme
Authors: Aimoto Saburo , Shimonishi Yasutsugu
Published: July 2006

The influences of anhydrous hydrogen fluoride on reduced hen egg-white lysozyme were investigated under standard conditions for peptide synthesis. 1) Enzymatically fully active protein was recovered in poor yield (5%) from reduced hen egg-white lysozyme after treatment with hydrogen fluoride. 2) The yield (29–33%) was improved by addition of 1,4-butanedithiol or l-cysteine during treatment of reduced hen egg-white lysozyme with hydrogen fluoride. 3) Tetragonal crystals which were indistinguishable from those of native hen egg-white lysozyme were recovered after treatment of reduced hen egg-white lysozyme with hydrogen fluoride in the presence of 1,4-butanedithiol, anisole and amino acid derivatives. Thus, the original intact lysozyme could be recovered from an HF-solution of the reduced form.
Studies on the Reactions of Bis(acetylacetonato)platinum(II) with Lewis Bases. I. Reactions with Tertiary Phosphines Leading to a Complex Containing Carbon-Bonded Unidetate Acetylacetonato Ligand and Preparation of New Alkylplatinum Complexes
Authors: Ito Takashi , Kiriyama Takashi , Yamamoto Akio
Published: July 2006

Addition of tertiary phosphines (PR3) to [Pt(acac)2] (acac=acetylacetonato-O,O′) causes the rearrangement of one of the O-bonded chelate acac ligands to a C-bonded form giving [Pt(acac)(γ-acac)PR3] (γ-acac=acetylacetonato-C3) (PR3=PPh3, 1a, and P(C6H11)3, 2a). Complexes 1a and 2a were isolated and characterized by means of elemental analysis, infrared and 1H- and 13C-NMR spectroscopy. Some reactions involving complex 1 were investigated. The mechanism of formation of a diethylplatinum complex in the reaction of [Pt(acac)2] with Al(OEt)Et2 and PPh3 is discussed taking into account the rearrangement of the acac ligand from the O-bonded chelate to a C-bonded form.
Photoinduced One-Electron Reduction of 1-Benzyl-3-carbamoylpyridinium Chloride and 3,5-Bis(ethoxycarbonyl)-2,6-dimethylpyridine
Authors: Kano Koji , Matsuo Taku
Published: July 2006

Photolysis of 1-benzyl-3-carbamoylpyridinium chloride (BNA+) in aqueous solution in the presence of diethylamine and/or ethylenediaminetetraacetate gives the 6,6′-dimer (1), a coupled product of the pyridyl radicals generated by one-electron transfer from alkylamine to photoexcited BNA+. Thermal one-electron reduction of BNA+ either with zinc dust/copper sulfate or with magnesium powder in aqueous alkaline medium yields the 4,6′-dimer (2) together with a small amount of 1. In the case of 3,5-bis(ethoxycarbonyl)2,6-dimethylpyridine (HEox), the 2,2′-dimer (3) is formed as an initial photoreduction product, which is converted into the 4,4′-dimer (4) and 1,2-dihydropyridine (5) upon prolonged irradiation.
Carbonylation of Olefins, Alcohols, and Saturated Hydrocarbons Using Cu(CO)n+ and Ag(CO)2+ Catalysts in BF3–H2O
Authors: Souma Yoshie , Sano Hiroshi
Published: July 2006

Olefins, alcohols, and saturated hydrocarbons reacted with carbon monoxide to give t-carboxylic acids in high yields using copper carbonyl and silver carbonyl catalysts at room temperature and in carbon monoxide at atmospheric pressure in BF3–H2O solutions. Dienes and diols also reacted with carbon monoxide to give mixtures of monocarboxylic acids, dicarboxylic acids and lactones. The concentration ratio of H2O/BF3 was maintained between 1 and 2 during the carbonylation reaction. There was no difference between the catalytic behavior of Cu(CO)n+ and that of Ag(CO)2+. The reaction rates for primary alcohols were very low in BF3–H2O, although they increased with the addition of H2SO4. The reaction rates for s-alcohol, t-alcohol and olefins in BF3-H2O remained unchanged upon the addition of H2SO4.
Luminescence of Pyridinols and Related Molecules
Authors: Kimura Ko , Nagai Ryo
Published: July 2006

Quantum yields of fluorescence and phosphorescence together with lifetimes at 77 K suggest that 2-pyridinol exists in the keto form in the excited states as well as in the ground state, and the lowest excited singlet and triplet states for 2-, 3-pyridinol, 2-methoxypyridine, and N-methyl-2-pyridone are (ππ*) states. The lowest triplet state for 4-pyridinol takes the keto form, and is assigned to (ππ*).
The Stability Constants of Nickel(II) Complexes with Chloride, Thiocyanate, Sulfate, Thiosulfate, and Oxalate Ions, as Determined by a Solvent Extraction Method
Authors: Murai Ryokichi , Kurakane Kiyoshi , Sekine Tatsuya
Published: July 2006

The stability constants of nickel(II) complexes in 1 mol dm−3 sodium perchlorate media were determined at 25 °C by means of a solvent extraction method. The values thus obtained for logβ1 and logβ2 are: 0.0 and no second complex (Cl−), 1.1 and 1.6 (SCN−), 1.0 and 1.4 (SO42−), 0.9 and 1.3 (S2O32−), and 3.7 and 6.6 (C2O42−), respectively.
A New Synthesis of α-Santalol
Authors: Sato Kikumasa , Inoue Seiichi , Takagi Yoshihiro , Morii Shigeki
Published: July 2006

A new synthesis of α-santalol (1) is described. 1-Benzyloxy-4-bromo-2-methyl-2-butene (6) was converted by the reaction with nickel carbonyl to the π-allylic nickel bromide complex (7), which reacted with (−)-π-bromotricyclene (8) to afford benzyl ether (2). The benzyl ether (2) was led to (1) (cis: trans=40: 60) by reductive cleavage of the benzyloxy group.
The Stereostructure of Acetylparabenzlactone and Its Conversion to a Lariciresinol-type Lactone
Authors: Niwa Masatake , Iguchi Masanobu , Yamamura Shosuke , Nishibe Sansei
Published: July 2006

Acetylparabenzlactone (1), an acetylation product of (−)-parabenzlactone (2), has been newly isolated from Parabenzoin trilobum Nakai, and the stereostructures of these two piperolignanolides have also been elucidated. Furthermore, the chemical conversion of 1 to a lariciresinol-type lactone (3) has been carried out.
The Photoelectrolytic Reaction of Chlorophyll–β-Carotene–Quinone Electrodes
Authors: Takahashi Fujio , Kikuchi Ryoichi
Published: July 2006

The NAD+ (nicotinamide adenine dinucleotide) reduction was carried out under illumination by using a platinum electrode coated with chlorophyll and quinone. Various quinones and β-carotene were used as components of the cathode layer to obtain a higher current density. The highest current density, 13 μA/cm2, was obtained in the case in which the cathode layer contained 0.01 μmol/cm2 of chlorophyll and the molar ratio of chlorophyll: chloranil : β-carotene was 1 : 1 : 2. The role of quinone and β-carotene in the cathode layer was discussed.
Studies on Lignoids in Lauraceae. II. Studies on Lignans in the Leaves of Machilus Japonica Sieb. et Zucc.
Authors: Takaoka Daisuke , Watanabe Keiko , Hiroi Mitsuru
Published: July 2006

From the leaves of Machilus japonica Sieb. et Zucc., four lignans were isolated; they have been found to be (+)-galbacin [1], (+)-galbelgin [2], (−)-licarin-B [4], and a new lignan, machilusin, whose structure can be described as [3a] or [3b].
The Reaction of Disodium Tetracarbonylferrate(–II) with Aldehydes
Authors: Yamashita Masakazu , Watanabe Yoshihisa , Mitsudo Take-aki , Takegami Yoshinobu
Published: July 2006

Disodium tetracarbonylferrate (–II) is an efficient catalyst for the dismutation of aromatic aldehydes to esters, 2RCHO→RCOOCH2R. Aliphatic ones give aldol-condensation products upon treatment with the ferrate. A successive reaction of the ferrate with an aldehyde, RCHO, and then with alkyl iodide, R’I, gives an ester, R’COOCH2R, after protonation. The mechanisms of these reactions are discussed.
Formation and Reactions of Alkoxydiaminosulfonium Salts
Authors: Minato Hiroshi , Okuma Kentaro , Kobayashi Michio
Published: July 2006

Ethoxydimorpholinosulfonium tetrafluoroborate and tetraphenylborate were prepared by ethylation of dimorpholino sulfoxide. They were readily hydrolyzed with water but did not react with methanol. In the reactions with nucleophiles, they acted as ethylating agent for β-picoline, triethylamine, diethylamine, methoxide ion, and chloride ion. When dimorpholino sulfide, 1-chlorobenzotriazole, and an alcohol were allowed to react at −80 °C, the main products were an alkyl chloride, dimorpholino sulfoxide, and morpholinium chloride. Alkoxydimorpholinosulfonium chloride was presumed to be the intermediate, which decomposed by an SN2-type nucleophilic attack of chloride ion on the alkyl group. When (+)-2-octanol was used, the 2-chlorooctane formed was of almost completely inverted configuration (enantiomeric excess, 97%). The yield of alkyl chlorides decreased in the order of methyl (80%), isopropyl (51), and t-butyl (20).
Coenzyme Models. VII. Micellar Catalysis of Acid-Catalyzed Hydration of 1-Dodecyl-1,4-Dihydronicotinamide
Authors: Shinkai Seiji , Ando Reiko , Kunitake Toyoki
Published: July 2006

The acid-catalyzed hydration reaction of 1-dodecyl-1,4-dihydronicotinamide was examined in cationic(CTAB) and anionic (SDS) micelles. The H3O+-catalysis(kH was negligibly small in the presence of the CTAB micelle and 225–521 M−1 s−1 in the presence of the SDS micelle, the difference being about 107-fold. The catalysis by carboxylic acids (kHA) was considerably suppressed in the CTAB micelle, but was promoted in the SDS micelle, suggesting the development of a cationic charge on a nitrogen atom of dihydropyridine at the rate-determining step. Brönsted plots for logkHA in the CTAB and SDS micelles vs. pKa of carboxylic acids gave straight lines with the slope of −0.8, the line for SDS being higher by two orders of magnitude than that for CTAB. These results indicate that a cationic charge (e.g., the lysine residue of alcohol dehydrogenase located very close to the bound NADH) may protect the NADH from hydration decay.
Regrioselectivity of Palladium(II)-Induced Intramolecular Cyclization of 2-(3-Methyl-2-butenyl)phenol
Authors: Hosokawa Takahiro , Yamashita Shinji , Murahashi Shun-Ichi , Sonoda Akio
Published: July 2006

Reaction of 2-(3-methyl-2-butenyl)phenol (1) with PdCl2 gives 2,2-dimethylchromene (3) and 2,2-dimethyl-4-methoxychroman (4) (six-membered products) predominantly, together with trace amounts of 2-isopropylbenzofuran (5) and 2-isopropenyl-2,3-dihydrobenzofuran (6) (five-membered products). The reaction involves attack of the oxygen atom of the phenoxyl group at 2- or 3-position of the allylic side chain. Addition of various sodium carboxylates to the reaction mixture changes the regioselectivity. In the presence of sodium salts of carboxylic acids bearing electron-releasing substituents, nearly equal amounts of five and six-membered products are formed. The presence of sodium salts of carboxylic acids bearing electron-withdrawing substituents results in the predominant formation of the six-membered products. These results are discussed en the basis of alternation of reactive Pd(II) species. Results obtained from 2-(2-butenyl)phenol (2) are also reported.
Gel Filtration of Aqueous Sodium Dodecyl Sulfate
Authors: Suzuki Hitoshi
Published: July 2006

The tail analysis of gel filtration was applied to a sodium dodecyl sulfate (SDS) solution using Sephadex G-50. This method is more simple and useful than the frontal analysis method formerly reported. The relative elution rate of SDS micelle, Rm, increased with an increase in the SDS concentration above CMC, reached a maximum near 16 mmol/l and then decreased up to 100 mmol/l. The application of the Laurent-Killander equation gave a micellar radius of 17.6 Å at CMC and 11.7 Å at the maximum Rm, corresponding to aggregation numbers of 35 and 80, respectively. The apparent decrease of Rm observed above 20 mmol/l was due to an structural change of the Sephadex gel caused by the addition of SDS. The micellar weight was estimated referring to a substance of known molecular weight; it was found to be constant in the region from 15 to 100 mmol/l SDS. The results of gel filtration of the SDS solution using CPG-10 as a gel column were similar to the case of Sephadex G-50; a micellar weight and an aggregation number of 25000 and 88, respectively, in the constant Rm range were obtained.
Proton Magnetic Resonance Spectra of Metal Ammine Complexes. VI. The trans-Effect in Cobalt(III) Amine Compounds as Studied by the Rate of Hydrogen-Deuterium Exchange
Authors: Sakaguchi Ushio , Maeda Koichi , Yoneda Hayami
Published: July 2006

The rate of the isotopic deuterium exchange has been measured for several cobalt(III) amine complexes in D2O. The substituents CN−, NO2−, and possibly SO32− decelerate the exchange of the amine protons trans to these ligands, leading in some cases to a smaller rate for these protons than for the cis ones. On the other hand, the trans-proton labilizing ligands include F−, Cl−, Br,−, H2O, CO32−, OCONH2−, N3−, CH3NH2, CH3COO−, and the malonate, fumarate, and oxalate ions. The above observation clearly indicates that the HD exchange rate can be a measure of the trans-effect of these ligand molecules.
Proton Magnetic Resonance Spectra of Metal Ammine Complexes. VII. Amine Proton Chemical Shifts in Bis(ethylenediamine)cobalt(III) Compounds
Authors: Sakaguchi Ushio , Yamazaki Shigeo , Yoneda Hayami
Published: July 2006

Amine proton chemical shifts have been measured for some cis-bis(ethylenediamine)cobalt(III) complexes in trifluoroacetic acid. The shifts can be explained quantitatively by the magnetic anisotropy of the central metal ion and by assuming fast conformational inversion of chelate rings. Discrepancy between the observed and the computed shift values is apparent, however, for the trans hydrogens of the cis-dicyano compound, which may be due to the ground-state trans-effect of the cyanide ion. The chemical shifts of amine protons of cis-tetraammine and cis-bis(trimethylenediamine)compounds have been briefly discussed.
Cyanoalkyl Complexes of Transition Metals. IV. Geometry and Spectroscopic Properties of Cyanomethyl Complexes of Palladium(II) and Platinum(II)
Authors: Suzuki Keinosuke , Ooyama Junichi , Sakurai Masami
Published: July 2006

A number of cyanomethyl complexes of palladium(II) and platinum(II) were prepared and characterized by proton nuclear magnetic resonance and infrared spectroscopy. It was shown that the methylene resonance, phenyl resonance, and a strong band at 550±5 cm−1 are acceptable criteria for deducing the geometry of the complexes MX(CH2CN)(PPh3)2 (M=Pd, Pt). The criteria allow us to assign the cis geometry to the bromo and iodo complexes of platinum(II) both of which showed an unusual methylene resonance. An approximately linear relationship holds between 2J(Pt–H) of trans-PtX(CH2CN)(PPh3)2 and that of trans-PtX(CH3)(PPh3)2 (X=Cl, Br, I, N3, NO2, NO3).
Epoxide Rearrangement. IV. Isomerization of Cyclohexene and 1-Methyl-cyclohexene Oxides over Solid Acids and Bases in Gas Phase
Authors: Arata Kazushi , Kato Kiyoshi , Tanabe Kozo
Published: July 2006

A large amount of diene compounds was found to form in the isomerizations of cyclohexene and 1-methylcyclohexene oxides catalyzed by solid acids and bases in gas phase. The catalysts which were quite inactive in liquid phase showed unexpectedly high activities in gas phase, indicating the different catalytic actions.
Spectroscopic Study of Concentration Fluctuation and Intermolecular Interaction in Liquid
Authors: Fujiyama Tsunetake , Kakimoto Masao , Suzuki Tetsuo
Published: July 2006

The band widths of the infrared absorption spectra were observed for binary solutions of methyl iodide, methyl cyanide, chloroform, and carbon disulfide. The observed bands are: the v1 fundamental of chloroform in carbon disulfide and in carbon tetrachloride; the v2 fundamental of methyl iodide in methyl cyanide, nitromethane, benzene, carbon disulfide, and carbon tetrachloride; the 2v2 band of methyl iodide in methyl cyanide, and the v8 and 2v8 bands of methyl cyanide in methyl iodide. The concentration dependence of a band width was explained in terms of the concentration fluctuation. The theory was compared with the observed band widths, together with the light-scattering data. A fluctuation volume was related with the intermolecular interactions in these binary solutions.
Stereochemical Studies of Elimination Reactions of 2-Bromobutane and 2,3-Dibromobutane over Alkali-Ion Exchanged Silica Gels
Authors: Misono Makoto , Aoki Yukio , Yoneda Yukio
Published: July 2006

The stereochemistry (anti or syn mode) of elimination reactions of 2-bromobutane and 2,3-dibromobutane over alkali-ion exchanged silica gels (Li, Na, K, and Cs) was determined at 100–300 °C from the products of the diastereomeric isomers of each alkyl bromide. They were erythro- and thero-2-bromobutanes-3-d1 and meso- and dl-2,3-dibromobutanes. The steric course of dehydrobromination of 2-bromobutane changed nearly reversibly between syn and anti mode by the partial exchange of a surface proton with K+ or Cs+ ion, although the surface structure seemed to remain unchanged by the exchange procedure. On the other hand, the exchange with Na+ or Li+ ion did not change the steric course. Dehydrobromination of 2,3-dibromobutane proceeded by anti mode over Na-, K-, and Cs–SiO2, while SiO2 and Li–SiO2 were not active. The poisoning effect of acidic and basic reagents as well as the indicator test revealed that basic sites played important roles over K- and Cs–SiO2 where anti elimination prevailed, and that weakly acidic sites were responsible for syn elimination.
Studies of Fragment Ion Distribution and Reaction with a Charge Spectrometer. VIII. Fragmentation Processes of Various Alkyl Halides
Authors: Ikuta Shigeru , Yoshihara Kenji , Shiokawa Takanobu
Published: July 2006

The breakdown curves for C2H5X, n-C3H7X, and n-C4H9X (X=Cl, Br, and I) were obtained by the use of a double mass spectrometer of the perpendicular type. The charge exchange mass spectra for alkyl bromide and alkyl iodide are found to be similar, although those for alkyl chloride are somewhat different from these for bromide and iodide. According to the molecular orbital calculation, the difference of the electronic configuration between chloride and bromide or iodide is found to correspond to the difference of the breakdown curves. The results obtained in this study using larger molecules support our previous analysis on the breakdown processes in smaller molecules: (1) direct scission of the bond which has lost one electron by the charge exchange reaction, (2) electron redistribution, and (3) secondary decomposition (and those of higher order) from the primary fragments. In the case of alkyl chloride, formation of the ion CnH2n+ is ascribed to the elimination of HX from the molecular ion in its electronically ground but vibrationally excited state.
The Polymorphic Crystallization of TiO2 under Hydrothermal Conditions. I. The Effect of Phosphate Ions on the Selective Crystallization of Anatase
Authors: Izumi Fujio , Fujiki Yoshinori
Published: July 2006

The hydrothermal growth of anatase has been investigated at 480–650 °C and 500–1000 atm. Only rutile was formed in KF solutions. On the other hand, anatase was found to crystallize in solutions containing 5 wt% KF+0.1–10 wt% K2HPO4 at temperatures up to 600 °C, accompanied by small amounts of K2Ti6O13 on the addition of 5–10 wt% of K2HPO4. The optimum growth conditions were: mineralizer solution, 5 wt% KF+1–2.5 wt% K2HPO4; temperature, 550–600 °C; pressure, 1000 atm. Anatase crystals were found as irregular aggregates of dipyramidal grains, blue and transparent. Individual crystals grown at a low supersaturation were characterized by well-developed {101} and {103} faces. The observed habit agrees with the expectations based on Hartman’s PBC theory. The presence of phosphate ions favored anatase formation in NH4F solutions as well, and the retrograde solubility of TiO2 was observed. The reaction scheme for anatase formation has been proposed. The polymorphic crystallization of TiO2 under hydrothermal conditions has been shown to be greatly affected by the complexing anions, such as fluoride or phosphate, in mineralizer solutions.
Substituent Effects in the Ionization of trans-2-Substituted Cyclopropanecarboxylic Acids
Authors: Kusuyama Yoshiaki , Ikeda Yoshitsugu
Published: July 2006

The ionization constants of trans-2-substituted cyclopropanecarboxylic acids were determined in water and 50% aqueous ethanol at 25 °C. The substituent effects thus obtained were interpreted by the use of the four parameter equations presented by Yukawa and Tsuno. The transmitting resonance effect of trans-cyclopropylene is about a quarter that of trans-vinylene and a half that of p-phenylene.
Photochemical Reaction of 9,10-Phenanthrenequinone with Hydrogen Donors. Behavior of Radicals in Solution as Studied by CIDNP
Authors: Maruyama Kazuhiro , Otsuki Tetsuo , Naruta Yoshinori
Published: July 2006

Behavior of radicals produced in the photochemical reaction of 9,10-phenanthrenequinone was investigated by use of CIDNP and ESR technique. By comparison of the sign of CIDNP signals in formation of and in decomposition (photochemical or thermal) of adducts, the rearrangement of adducts, e.g., from the 1,2-adduct to 1,4-adduct and vice versa, was proposed. Although the adducts are stable enough to isolate in general, they decomposed photochemically or thermally to give the mixture of 9,10-phenanthrenediol (or its quinhydrone), the dehydrogenated dimer of hydrogen donor, and others as minor product.
Lumiflavin-sensitized Photooxygenation Accelerated by Adenine. II. The Photolysis of 14C-labeled Reactants
Authors: Yoshimura Akio , Kato Shunji
Published: July 2006

Radioactive tryptophan, histidine, methionine, and guanine were photolyzed in the presence of lumiflavin either with or without adenine, and the reaction products were compared chromatographically. Adenine accelerated these lumiflavin-sensitized photooxygenation reactions, and no effect of adenine on the reaction products was shown.
Ligand Isotopic Exchange Kinetics of Tris(acetylacetonato)titanium(IV) Perchlorate in Acetonitrile
Authors: Nishizawa Masato , Kido Hiroaki , Kinoshita Isamu , Soma Yoshikuni , Saito Kazuo
Published: July 2006

The rate of isotopic exchange between tris(acetylacetonato)titanium(IV) ions and acetylacetone-14C3 in enol form is measurable at −20 °C in acetonitrile. Water, free ligand and a strong acid catalyse the exchange.
C-13 NMR Chemical Shifts and Charge Densities of Substituted Thiophenes—The Effect of Vacant dπ Orbitals
Authors: Osamura Yoshihiro , Sayanagi Osamu , Nishimoto Kichisuke
Published: July 2006

The effect of vacant dπ orbitals on the charge distributions of heteroatomic systems containing sulfur and halogens is discussed. From an appropriate estimation of the Coulomb and resonance integrals associated with the vacant dπ orbitals, a linear relationship is obtained between charge density and C-13 chemical shift. For a discussion of the reactivity for electrophilic substitution of thiophene, the contribution of dπ orbitals of sulfur atom should be taken into account.
Dipolar Interaction in TEMPAD Biradical. II
Authors: Nakajima Akira , Yamauchi Jun , Ohya-Nishiguchi Hiroaki , Deguchi Yasuo
Published: July 2006

The EPR of TEMPAD single crystals diluted in diamagnetic matrices was studied. The results of the 10% TEMPAD were almost the same as those of the very dilute one studied previously. In the case of the 25% TEMPAD, the spectra are composed of three parts. The central broad line, whose linewidth was analyzed in comparison with the pure TEMPAD case using the three-dimensional Anderson-Weiss formula, is the spectrum of clusters constructed by the free radicals. The side lines with the hyperfine splitting are the spectrum of the isolated TEMPAD molecule, and the outer broad lines are from the molecules coupled in pairs along the a-axis. The EPR spectra of the pure TEMPAD at very low temperature were also measured in order to have information concerning the dipolar interaction in the pure crystal. These spectra are the superposition of the spectra caused by the intra-molecular dipolar interaction and of the spectra due to impurities. All the results were explained with the suitable molecular stack model and the triplet exciton theory.
Microwave Spectrum of syn-Acetaldehyde Oxime-d
Authors: Ohashi Osamu , Ishihara Ryoji , Murakami Kakuji , Sakaizumi Takeshi , Onda Masao , Yamaguchi Ichiro
Published: July 2006

The microwave spectrum of syn-acetaldehyde oxime-d was investigated in the frequency region 7.5∼35 GHz. Several a-type R-branch transitions were identified and the following rotational constants in MHz were obtained: A=45682, B=4057.21, C=3806.13. The transitions of syn-acetaldehyde oxime-d are split into the A and E species by tunneling of the methyl group through the potential barrier hindering the internal rotation. From these separations the height of the barrier was determined to be 1948 cal mol−1. The dipole moment of the molecule was determined to be 0.938 D from the Stark effect.
Effect of Water on Crystallization Process of Coesite
Authors: Kameyama Tetsuya , Naka Shigeharu
Published: July 2006

The effect of water on crystallization process of coesite was studied at 450 to 700 °C under 30 kbars by using different starting materials. The presence of water under compression and heating was found to have remarkable effects not only on the kinetics of crystallization of coesite also on the morphology of metastable quartz, consequently of coesite crystals. Under anhydrous condition, from amorphous silica and silica glass, the spherulitic aggregates of metastable quartz appeared. The coesite crystals were developed in the spherulites of quartz as elongated crystals with different sizes and appeared to be defective. When synthetic quartz was used as a starting material, however, no formation of spherulitic aggregates of quartz was observed and granular coesite crystals were obtained. Under hydrous condition, granular coesite crystals with homogeneous size were developed rapidly at 450 °C from both amorphous silica and silica glass through the discrete particles of metastable quartz.