bluuebunny/crossref_metadata_2025 huggingface dataset:
Aryliminodimagnesium Reagents. XI. Two-Electron Oxidation of the Reagent Molecules in the Reaction with Some Oxidizing Agents and with Strongly Push-Pull Substituted α-Benzylideneacetophenones
Authors: Okubo Masao , Yoshida Shunsei , Egami Yoshiji , Matsuo K\={o}ji , Nagase Shigeru
Published: July 2006

The reactions of an aryliminodimagnesium reagent (ArN(MgBr)2) with four oxidizing agents ((i): I2, OsO4, C6H5IO2, I2O5) and four push-pull substituted α-benzylideneacetophenones(ii) were examined. In the reactions with (i), the maximum yield of sym-azobenzene was 50%. In the reactions with (ii), in addition to products formed via condensation and the typical radical processes, unexpected products formed via cleavages of C=C and Cβ–H bonds were observed. Summarizing these results, a pathway involving the formation of arylnitrene-like species via disproportionation of arylaminyl radicals (Ar\.{N}MgBr) has been proposed.
α,β-Epoxy Sulfoxides as Useful Intermediates in Organic Synthesis. X. An Improved Synthesis of α,β-Unsaturated Carbonyl Compounds from Carbonyl Compounds with Carbon Homologation through α,β-Epoxy Sulfoxides
Authors: Satoh Tsuyoshi , Itoh Masayuki , Ohara Teruhiko , Yamakawa Koji
Published: July 2006

Treatment of the α,β-epoxy sulfoxides derived from ketones and chloromethyl phenyl sulfoxide or 1-chloroalkyl phenyl sulfoxides with lithium perchlorate in the presence of tributylphosphine oxide in toluene at 110 °C for about 1–3 h gave α,β-unsaturated aldehydes or α,β-unsaturated ketones in high yields. In contrast to these results, the α,β-epoxy sulfoxides derived from aldehydes did not give the desired α,β-unsaturated ketones. In this case, a sequential treatment of the α,β-epoxy sulfoxides with benzenethiolate and m-chloroperbenzoic acid afforded α-phenylsulfinylated ketones, which were heated in toluene at 110 °C to give the desired enones in good overall yields. The oxidation of the α,β-unsaturated aldehydes obtained by this method gave α,β-unsaturated carboxylic acids in high yields. These procedures afforded a new method for the synthesis of α,β-unsaturated carbonyl compounds, including α,β-unsaturated esters, from carbonyl compounds with carbon homologation.
Preparation of New Nitrogen-Bridged Heterocycles. 15. Synthesis and Reaction of 1,9a-Dihydropyrido[2,1-c][1,4]thiazines
Authors: Kakehi Akikazu , Ito Suketaka , Yonezu Shingo , Maruta Katsunori , Yuito Kazuhiro , Shiohara Morio , Adachi Kyoko
Published: July 2006

Alkaline treatment of 1-[2-(substituted methylthio)vinyl]pyridinium bromides, readily obtainable from the S-alkylation of pyridinium 1-(thiocarbonyl)methylides with various alkyl bromides such as bromoacetonitrile, ethyl bromoacetate, and some phenacyl bromides, gave smoothly 1,9a-dihydropyrido[2,1-c][1,4]thiazine derivatives as almost isomeric mixtures. These dihydropyridothiazines are very unstable and decomposed rapidly at ordinary temperature, but by treating them with a dehydrogenating agent such as lead tetraacetate (LTA) or 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) at 0 °C the desulfurized and the rearranged aromatic indolizine derivatives were formed in moderate to good yields.
Metal Ion-Catalyzed Reduction of Substituted Nitrosobenzenes by 1-Benzyl-3,5-bis(1-pyrrolidinylcarbonyl)1,4-dihydropyridine in Acetonitrile
Authors: Awano Hiroshi , Takemoto Kazuo , Ohya Hirohisa , Tomio Minaki , Tamagaki Seizo , Tagaki Waichiro
Published: July 2006

Metal ion catalyzed reduction of substituted nitrosobenzenes by 1-benzyl-3,5-bis(1-pyrrolidinylcarbonyl)1,4-dihydropyridine (BPDH) in acetonitrile has been studied for seven bivalent metal ions. The reduction of N-methylacridinium salt (MA) has also been examined. In the former cases, it was found that the metal ions catalyze the reduction by forming a 1:1 complex with BPDH according to a Michaelis–Menten type saturation kinetics which allowed to derive the association constants, KM, for the complexation and the second-order rate constants, k2, for the reduction. A linear relationship was found between logk2 and the ionization potentials of metal ions with a positive slope. A linear Hammett relationship was also observed between logk2 and the Hammett σ constants with a positive ρ value for three metal ions. These results suggest that a bivalent metal ion is sandwiched between the BPDH and the substrate and acts as a Lewis acid to stabilize the incipient N-oxide anion of the substrate which is formed by hydride transfer in the transition state. In the cases of MA, all metal ions inhibited the reduction. Repulsion between the positive charges of the metal ion-BPDH complex and the substrate salt appears to be prevailing.
Atropisomerism of Zinc Tetrakis(o-cyanophenyl)porphyrins. The Crystal Structure of the αβαβ-Isomer and the Atropisomerization Rates
Authors: Hatano Keiichiro , Kawasaki Kyoko , Munakata Sonono , Iitaka Yoichi
Published: July 2006

The structure of one of the four atropisomers of tetrakis(o-cyanophenyl)porphyrin has been determined as the zinc complex by X-ray crystallographic methods. The five-coordinate zinc porphyrin with pyridine as the axial ligand also has a pyridine solvate in the crystal lattice. The conformation of the o-cyanophenyl rings is αβαβ as predicted previously. The two nitrogen atoms of the CN groups on the same side of the coordinated pyridine have close intramolecular contacts to pyridine at the van der Waals distance. However, the structural parameters, bond distances and angles of this molecule do not indicate distinct steric effects of the CN groups. Thermal atropisomerization among the four zinc porphyrin atropisomers occurs in solution. The quantitative composition of the atropisomers at equilibrium and the rates of the isomerization reaction have been determined with aliquots separated by TLC. A nonstatistical equilibrium distribution of the atropisomers suggests some mutual interactions among the CN groups. The slower isomerization rates of the zinc complexes compared to those of the free base have been discussed in connection with the molecular structure.
Studies of a Peptide Antibiotic “Gratisin”. II
Authors: Tamaki Makoto , Takimoto Michiaki , Muramatsu Ichiro
Published: July 2006

In order to investigate the structure-activity relationship of the “gratisin”-related peptide, cyclo(–Val–Orn–Leu–d-Phe–Pro–d-Tyr–)2 (GR-I), its two analogs, cyclo(–Val–Orn–Leu–d-Ala–Pro–d-Tyr–)2 (6a) and cyclo(–Val–Orn–Leu–d-Phe–Pro–d-Ala–)2 (6b), were synthesized. The CD spectra of these synthetic peptides in an aqueous solution were similar to that of GR-I, indicating that these peptides have similar conformations in an aqueous solution. The activity of 6b was half that of GR-I, whereas 6a did not show any antibiotic activity. These results indicated that the phenyl group of the d-Phe residue preceding the Pro residue is essential for exhibiting the activity, while the p-hydroxyphenyl group of the d-Tyr residue following the Pro residue is not essential.
Synthesis of 4-Amino-2(5H)-furanones through Intra- and Intermolecular Nitrile Addition of Ester Enolates. Construction of Carbon Framework of an Antitumor Antibiotic Basidalin
Authors: Hiyama Tamejiro , Oishi Haruhito , Suetsugu Yukari (nee Kusano) , Nishide Kiyoharu , Saimoto Hiroyuki
Published: July 2006

Two new routes to 4-amino-2(5H)-furanones are disclosed. The one is based on the reaction of a magnesium enolate of t-butyl acetate or propionate with O-protected cyanohydrins followed by acid-treatment which effects hydrolysis of the ester group, deprotection, olefin isomerization and lactonization all in a single operation. The other is base-induced ringclosure of α-acyloxy nitriles. The two methods are applied to construction of the carbon framework of an antitumor antibiotic basidalin.
Resonance Raman and 129I Mössbauer Spectroscopic Study of Phenothiazine–Iodine Complexes
Authors: Sakai Hiroshi , Muraishi Shu-ichi , Maeda Yutaka
Published: July 2006

Resonance Raman and 129I Mössbauer spectroscopy have been applied to the phenothiazine–iodine (PT–In) complexes, which exhibit relatively low electrical resistivities. It is shown from the resonance Raman spectra that the two iodine species in the PT–I3 and PT–I2.6 complexes are present in essentially the same chemical form, consisting of a distorted I3− unit and an I2 unit strongly coordinated to the I3− unit. The 129I Mössbauer spectrum, consistent with the results of the Raman spectra, suggests that the PT–I2.6 complex can be approximately formulated as (PT)53+[(I3)3(I2)2]3−, in which about three electrons per five PT molecules are transferred to the iodine and the transferred electrons are delocalized on the thirteen iodine atoms. The radical salt is recognized as a partially oxidized mixed-valence compound. The formation of the complex is quite similar to that of the perylene–I3 complex, which has a low electrical resistivity.
Racemic Structures of Organic Ammonium Salts of N-Acetyl-Dl-2-aminobutyric Acid and N-Acetyl-Dl-norvaline and Optical Resolution by Preferential Crystallization of Dl-Ammonium Salts
Authors: Shiraiwa Tadashi , Yoshida Hirokazu , Tsuda Makoto , Kurokawa Hidemoto
Published: July 2006

The racemic structures of the ammonium salts (AM salts) and seven organic ammonium salts of N-acetyl-Dl-2-aminobutyric acid (Dl-AcAbu) and N-acetyl-Dl-norvaline (Dl-AcNva) were studied on the basis of thermodynamic analyses to explore the possibility of optical resolution by preferential crystallization. An empirical equation has been derived from thermodynamic data at melting points of ammonium and organic ammonium salts of N-acyl-Dl-amino acids to predict racemic structures around room temperature. The AM salts of Dl-AcAbu and -AcNva exist in conglomerate around room temperature. It is possible to resolve optically these Dl-AM salts by preferential crystallization in ethanol at 10 °C, and the successive preferential crystallization followed by purification gave d- and l-2-aminobutyric acids and -norvalines with optical purities close to 100%.
Aldol Condensation Reaction between Formaldehyde and Acetone over Heat-Treated Synthetic Hydrotalcite and Hydrotalcite-Like Compounds
Authors: Suzuki Eiichi , Ono Yoshio
Published: July 2006

Synthetic hydrotalcite, Mg6Al2(OH)16CO3·4H2O, and its analogues were synthesized, heat-treated at 773 K, and used as catalysts for the title reaction to form methyl vinyl ketone (MVK) at 673 K. MVK was formed over all the catalysts examined, the highest MVK yield (20% on acetone basis) being found over the heat-treated hydrotalcite.
Circular Dichroism Spectra of the Dicobalt(III) Complexes Containing Two Bridging μ-Hydroxo Ligands
Authors: Ama Tomoharu , Kawaguchi Hiroshi , Yasui Takaji
Published: July 2006

Five cobalt(III) complexes, [(gly)2Co(μ-OH)2Co(en)2]2+ (two geometrical isomers), [(edda)Co(μ-OH)2Co(en)2]2+ (two geometrical isomers), and [(nta)Co(μ-OH)2Co(en)2]Cl, were newly prepared and optically resolved. Their structures were assigned on the basis of visible and UV absorption, 1H NMR, and circular dichroism (CD) spectral data. It was found that the CD contributions of the two different cobalt(III) chromophores are additive in the present complex systems. The vicinal CD which is induced on one of the two cobalt chromophores by the other chiral cobalt chromophore was strong (|Δε|: ca. 2). These complexes are stable for several days in aqueous solution.
Studies of the Hydrous Niobium(V) Oxide Ion Exchanger. IV. The Rate of the Isotopic Exchange of Sodium Ions between the Exchanger in the Na+ Form and Aqueous Solutions
Authors: Inoue Yasushi , Yamazaki Hiromichi , Ikeda Mitsuji
Published: July 2006

The rate of the isotopic exchange of sodium ions between the hydrous niobium(V) oxide ion exchanger in the Na+ form and aqueous solutions was determined radiochemically. Since the fractional attainment of equilibrium was independent of the sodium-ion concentration in the solutions (≥0.1 mol dm−3), and inversely proportional to the square of the particle radius, the isotopic exchange rate on the hydrous niobium(V) oxide is controlled by the diffusion of the sodium ions in exchanger particles. The self-diffusion coefficients of sodium ions (D=3.1×10−7 cm2 s−1 at 25 °C) and their activation energy (Ea=27±4 kJ mol−1) were also determined.
Association of Naphthalene and Its Methyl Derivatives with Cyclodextrins in Aqueous Medium
Authors: Fujiki Motohisa , Deguchi Toshio , Sanemasa Isao
Published: July 2006

Formation constants of naphthalene and its (1- and 2-)methyl and (1,4-, 1,5-, and 1,8-)dimethyl derivatives with α-, β-, and γ-cyclodextrins (CyD) were determined in the aqueous medium in the presence of excess CyD. The technique used to study associations between host (CyD) and guest(hydrocarbon) is based on the facts that the guest molecules can be driven out to gaseous phase by introducing an inert gas at a constant flow rate into the aqueous solution and that the volatilization rate of guest decreases with increasing association with the host in aqueous solution. The 1:1 and 2:1 (host:guest) formation constants were evaluated at 25 °C. From the formation constant estimated, a host–guest spatial-fitting model for each association complex is presented.
Depletion-Mode Field Effect Semiconductor Sensor with Cation-Sensitive Polymer Membranes
Authors: Okawa Yusuke , Sukigara Mitsunori , Yoshida Shoichiro , Watanabe Tadashi
Published: July 2006

Semiconductor ion sensors based on the surface conductance change due to a variation in the depletion layer thickness have been constructed. An n-SnO2 electrode was coupled with four kinds of cation-sensitive polymer membranes (Fe3+- and Cu2+-exchanged Nafion membranes and poly(vinyl chloride)-supported dioctyl phthalate membranes containing a neutral carrier, valinomycin or nonactin), and its surface conductance was measured under depletion conditions as a function of the cation concentration. The sensor exhibited sensitivity to Fe3+, Cu2+, K+, or NH4+ at levels higher than 10−4 mol dm−3 within 10 s. The sensor response was analyzed in terms of (1) the dependence of the surface conductance on the surface band bending and (2) the potential difference at solution/membrane interfaces. From the analysis, it is confirmed that the membranes show nearly Nernstian behavior and that the semiconductor acts as a potentiometric transducer. The applicability of the depletion-mode semiconductor sensor is discussed.
Infrared Spectroscopic Conformational Analysis of Polystyrene Resin-Bound Human Proinsulin C-Peptide Fragments. β-Sheet Aggregation of Peptide Chains during Solid-Phase Peptide Synthesis
Authors: Narita Mitsuaki , Honda Shinya , Umeyama Hiroshi , Ogura Toshihiko
Published: July 2006

Conformational analysis of human proinsulin C-peptide fragments bound to cross-linked and soluble polystyrene resin matrices was performed using IR absorption spectroscopy. The conformational analysis of octa- and tridecapeptides in the swollen and solid states revealed that both peptides easily interacted with each other through intermolecular hydrogen bonding to form a β-sheet aggregation even at a low loading of peptide chains on the matrices. The high potential of the resin-bound peptides for the β-sheet formation was compatible with that of the corresponding peptides free from macromolecular protecting groups and was predicted using the average coil conformational value, 〈Pc〉, of each peptide. The significance of the results is discussed in connection with solid-phase peptide synthesis. Effects of shear stress on conformational transformations of resin-bound peptides was also examined in the solid state.
One-Pot Ortho Hydroxylations of 2-(1-Hydroxyalkyl)naphthalenes and (1-Hydroxyalkyl)benzenes
Authors: Tanoue Yasuhiro , Terada Akira , Seto Iwao , Umezu Yasuo , Tsuge Otohiko
Published: July 2006

Hydroxylations of 2-(1-hydroxyalkyl)-1,4,5,8(or 1,4,5,6,8)-tetra(or penta)methoxynaphthalenes and 2-(1-hydroxyalkyl)-1,4-dimethoxybenzenes at the 3-position were accomplished by a one-pot procedure. The same procedure has been found to be applicable to 2-(1-hydroxyalkyl)naphthalenes and (1-hydroxyalkyl)benzenes having no methoxyl substituent.
New Application of Solid Acid to Carbon–Carbon Bond Formation Reactions: Clay Montmorillonite-Catalyzed Aldol Reactions of Silyl Enol Ethers with Aldehydes and Acetals
Authors: Kawai Motomitsu , Onaka Makoto , Izumi Yusuke
Published: July 2006

A new attempt of utilizing solid acid to the cross aldol reaction of silyl enol ethers with aldehydes or acetals has been investigated. Among solid acids employed, the reaction is promoted most effectively by a catalytic amount of aluminium ion-exchanged montmorillonite (Al-Mont). Simple diastereoselection is significantly sensitive to the nature of the reaction solvent used in the Al-Mont-catalyzed reaction. When the aluminium ions in Al-Mont were replaced by protons or titanium ions in order to investigate the cation effect, almost the same results were observed on simple diastereoselectivity and diastereofacial selectivity. This fact suggests that the metal cations in montmorillonite do not work as Lewis acid in the present aldol reaction. The acid catalysis of montmorillonite in the present aldol reaction is discussed in comparison with the catalytic behavior of some homogeneous acids.
Practical Syntheses of Immunologically Relevant β-Glycosides of 2-Acetamido-2-deoxy-d-mannopyranose. Methyl N-Acetyl-β-d-mannosaminide, N-Acetyl-β-d-mannosaminyl-(1→6)-d-galactose, and Methyl N-Acetyl-β-d-mannosaminyl-(1→4)-α-d-glucopyranoside
Authors: Kaji Eisuke , Lichtenthaler Frieder W , Nishino Takashi , Yamane Aya , Zen Shonosuke
Published: July 2006

Highly stereoselective, expedient syntheses are described for three immunologically relevant β-glycosides of N-acetyl-d-mannosamine, i.e. β-d-ManpNAc-1-OMe (8), β-d-ManpNAc-(1→6)-d-Gal (15), and β-d-ManpNAc-(1→4)-α-d-Glcp-1-OMe (23). Basic mannosamine progenitor in each case is 3,4,6-tri-O-benzoyl-2-(benzoyloxyimino)-2-deoxy-α-d-arabino-hexopyranosyl bromide (1a), which via the three step-sequence β-selective glycosidation → hydroboration → deblocking is converted to 8, 15, and 23 in overall yields of 61, 56, and 39% for the glycosyl acceptors methanol, 1,2:3,4-di-O-isopropylidene-α-d-galactose, and methyl 2,3,6-tri-O-benzyl-α-d-glucopyranoside, respectively.
Condensation and Cyclization Reactions of 2-Hydrazinobenzimidazole, -benzoxazole, and -benzothiazole
Authors: Badr M Z A , Mahmoud A M , Mahgoub S A , Hozien Z A
Published: July 2006

2-Hydrazinobenzoxazole (1), -benzimidazole (2), and benzothiazole (3) were condensed with ethyl chloroformate and/or diethyl oxalate to produce, 1,2,4-triazolo- and 1,2,4-triazino-fused ketones of the title azoles respectively. Condensation of 1 and 2 with aromatic aldehydes and/or acetic anhydride produced, 3-aryl- and 3-methyl-substituted 1,2,4-triazolo-fused azoles respectively. The hydrazines 1 and 2 cyclized with acetylacetone to produce the corresponding 2-(1-pyrazolyl) derivatives. 2-Acetylthiazolobenzimidazole reacted with hydroxylamine and/or alkylamines, to produce the corresponding condensation products. Also it condensed with aromatic aldehydes to give the chalcones. When reacted with benzenediazonium salt, it gave the corresponding 2-arylazo-substituted compounds.
The Crystal Structure of the β′1 Form of Optically Active α-Monostearin
Authors: Goto Midori , Kozawa Kozo , Uchida Tokiko
Published: July 2006

The crystal structure of the β′1 form of (R)-α-monostearin has been determined. The space group is P212121, with a=4.943(1), b=8.858(2), c=101.05(1)Å, and Z=8. The two independent molecules in the title compound have different conformations.
The Crystal Structure and Intramolecular Electron Transfer of 1′,1'″-Diethylbiferrocenium Triiodide at 298 and 140 K
Authors: Konno Michiko , Sano Hirotoshi
Published: July 2006

The crystal structure of 1′,1'″-diethylbiferrocenium triiodide, (EtFcFcEt)+ I3−, was determined by means of X-ray diffraction. The crystals at 298 and 140 K are found to be monoclinic, with the P21⁄c space group and with Z=2. At 298 K, a=9.7557(10), b=9.9772(12), c=13.8216(13) Å, β=107.625(9)°, and U=1282.18(23) Å3, while at 140 K, a=9.6931(17), b=9.8065(22), c=13.7373(19) Å, β=107.642(15)°, and U=1244.4(4) Å3. The structures are refined to R=0.049 at 298 K and R=0.036 at 140 K. The (EtFcFcEt)+ cations and I3− anions sit on a crystallographic center of symmetry both at 298 and at 140 K, and the two ferrocenyl(Fc) units are crystallographically equivalent. The ethyl group in each ethylcyclopentadienyl(EtCp) group is not parallel to the fulvalene moiety, but the terminal CH3 group moves away with the 60° inclination from the Cp plane. An appreciable interaction seems to exist between the Cp ring of the cation and the I3− anion along the a+c⁄2 direction, but the interaction among the cations along the a axis seems to be so weak as to be negligible.
S-Bridged Polynuclear Complexes. II. Formation and Some Properties of [M{Co(l-cys-N,S)3}2]-Type Complexes (M=Fe(III), Co(III), and Ni(II); l-cys=l-cysteinate)
Authors: Aizawa Sen-ichi , Okamoto Ken-ichi , Einaga Hisahiko , Hidaka Jinsai
Published: July 2006

Three trinuclear complexes with ΔLll- and/or ΛLll-fac(S)-[Co(l-cys-N,S)3] terminals, and ΔLllΔLll-,ΔLllΛLll-, and ΛLllΛLll-[Fe{Co(l-cys-N,S)3}2]3−, ΔLllΛLll-[Co{Co(l-cys-N,S)3}2]3− and ΔLllΔLll-[Ni{Co(l-cys-N,S)3}2]4−, were newly prepared. These complexes were characterized from their electronic absorption, CD, and 13C NMR spectra. Each reaction of ΔLll-fac(S)-[Co(l-cys-N,S)3]3− with Fe(II) and Co(II) was accompanied by the inversion of the absolute configuration of the one or both terminals to give the ΔLllΛLll and ΛLllΛLll isomers, while the reaction with Fe(III), Co(III), or Ni(II) proceeded with the retention of the terminal to give the ΔLllΔLll isomer. The voltammetric study revealed that the formal potential of ΔLllΔLll-[Fe{Co(l-cys-N,S)3}2]3− (−0.16 V) is more anodic than that of ΔLllΔLll-[Co{Co(l-cys-N,S)3}2]3− (−0.43 V). These redox potentials are discussed in relation to the formation ratios of the isomers for the trinuclear complexes.
A Facile Synthesis of Oxetane Derivatives for Preparing Cross-Linked Polyoxetane Resins Bearing the Bromide at the Spacer End
Authors: Motoi Masatoshi , Suda Hiroshi , Shimamura Katsuhiko , Nagahara Shinsuke , Takei Mitsuru , Kanoh Shigeyoshi
Published: July 2006

3-(6-Bromo-2-oxahexyl and 8-bromo-2-oxaoctyl)-3-methyloxetanes, and 1,8- and 1,10-bis(3-methyl-3-oxetanyl)-2,7-dioxaoctane and -2,9-dioxadecane were readily prepared in fairly good yields by the reaction of 3-hydroxymethyl-3-methyloxetane (1) with tetra- and hexamethylene dibromides in the presence of a phase-transfer catalyst. The formation of the mono- and disubstituted products depends upon the molar ratios of the dibromide to 1. The optimum reaction conditions for the etherification of 1 with tetramethylene dibromide were searched. The (ω-bromo-2-oxaalkyl)oxetanes were polymerized to give soluble polyoxetanes (\barMn 3500–5500) by cationic ring-opening polymerization. The use of the bisoxetanes, a new cross-linking agent, as a comonomer gave insoluble elastic polyoxetane resins having a pendant bromide at the spacer end.
Synthesis and X-Ray Crystal Structure of [54](1,2,3,4)Ferrocenophane
Authors: Hisatome Masao , Yamashita Rin-ichi , Watanabe Jun , Yamakawa Koji , Iitaka Yoichi
Published: July 2006

The title compound bridged with four pentamethylene chains has been synthesized by stepwise construction of a pentamethylene bridge via formation of a three-carbon bridge followed by insertion of two carbon units. Crystal structure of the phane has been determined by X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21⁄n with unit cell parameters a=16.691(10), b=9.858(5), c=15.237(8) Å, β=112.43(6)°, and z=4. The structure parameters of the ferrocene moiety fall in normal ranges. Characteristic features are noted in the methylene bridges. The γ-methylene carbons undergo large thermal vibration, and apparent shortening of the bond lengths by oscillatory motions of atoms is seen.
Stress Relaxation of Alginate Gels Crosslinked by Various Divalent Metal Ions
Authors: Yonese Masakatsu , Baba Kazuhiko , Kishimoto Hiroshi
Published: July 2006

Rheological properties of Alginate (Alg) gels were studied by measuring tensile stresses under small strains. The Alg gel rods were prepared in CaCl2, SrCl2, BaCl2, and Pb(NO3)2 solutions in the range of 0.03–1.0 mol dm−3. Their stresses showed long relaxation processes. By curve fitting method, equilibrium elastic moduli Ge, spontaneous elastic moduli Ge+Gr and relaxation times τ were obtained. The results Ge were independent of strains γ, and Gr and τ increased as increasing γ. The effects of Ca ion concentrations CCa on the elasticities were discussed by taking account of the ratio of Ca ion bindings obtained by dialysis equilibrium and that of junction formation obtained by circular dichroism. The values of Ge were analyzed by the theory of swollen gels. The number of the junctions was found to be constant in the region of CCa>0.03 mol dm−3, and slight increases of Ge to be due to changes of the water content and the density of the Alg gels. The magnitudes of Ge and Gr depended on the kind of counterions, and decreased in the order, Ba->>Ca->Sr-> PbAlg; this was almost the same as that of the ion selectivities.
Magnetic Behavior of Spin-Crossover Iron(III) Complexes Adsorbed on the Surface of Silicon Dioxide and Metal Dilution Effects on Magnetism
Authors: Maeda Yonezo , Tomokiyo Masahiro , Kitazaki Kenji , Takashima Yoshimasa
Published: July 2006

The effects of metal dilution and adsorption on the surface of silicon dioxide on the spin-crossover behavior of [Fe(acpa)2]PF6, [Fe(acpa)2]BPh4, and [Fe(bzpa)2]PF6, which undergo fast spin-state interexchange on the 57Fe Mössbauer timescale have been studied by using 57Fe Mössbauer and EPR spectroscopies, powder X-ray diffraction and magnetic susceptibility, where Hacpa is N-(1-acetyl-2-propylidene)-2-pyridylmethylamine and Hbzpa N-(1-benzoyl-2-propylidene)-2-pyridylmethylamine. Solid solution compounds, [FexCo1−x(acpa)2]BPh4(x=0.035 and 0.074) and [Fe0.05Co0.95(bzpa)2]PF6 exhibit spin-crossover phenomena. No difference in the spin-state interexchange rate is observed between the diluted compound and the corresponding undiluted one as far as the rates are evaluated by Mössbauer spectroscopy. Mössbauer spectra for [Fe0.074Co0.926(acpa)2]PF6 exhibit only a pair of quadrupole doublets assigned to the low-spin state in the temperature range from 78 to 298 K. The spin-state interexchange rates for [Fe(acpa)2]BPh4 and [Fe(bzpa)2]PF6 adsorbed on the surface of silicon dioxide become slow compared to those for the corresponding pure complexes and the narrowing of the spin-state transition temperature range is observed. On the contrary no detectable differences in the spin-state interexchange rates are observed between the Mössbauer spectra for [Fe(acpa)2]PF6 adsorbed on the surface of silicon dioxide and that for the pure complexes. These observations are interpreted in terms of a spin-state transition behavior in these complexes which is affected by the packing state in the solid state, which is dependent on the characteristic structure of the respective complex.
NMR Spectroscopic Study of the Conformational Preference of Methoxycarbonyl and Methyl Substituted Thiophenecarbaldehydes. Possibility of a Hydrogen-Bond-Like Interaction between Formyl C–H and the Ester Carbonyl Group
Authors: Satonaka Hajime , Abe Kazuhisa , Hirota Minoru
Published: July 2006

The predominance of planar C–H/O=C approached conformations in methyl 3-formyl-2-, 2-formyl-3-, and 4-formyl-3-thiophenecarboxylates was shown experimentally by the chemical shifts of the formyl protons, the unusually large 1JCH values of the formyl groups, and their infrared C–H and C=O absorptions. The stability of the C–H/O=C approached conformation was attributed to the hydrogen-bond-like interaction between the two groups. The considerably large positive bond population between non-bonded H/O and the additional charge separation indicated by the MNDO calculations supported the presence of the intramolecular hydrogen bond.
Enantioselective Reduction of 2-Methyl-3-oxopropionate by Bakers’ Yeast
Authors: Nakamura Kaoru , Miyai Takehiko , Ushio Kazutoshi , Oka Shinzaburo , Ohno Atsuyoshi
Published: July 2006

Various esters of 2-methyl-3-oxopropionic acid were subjected to the reduction with bakers’ yeast. Effects of size and bulkiness as well as hydrophobicity of alcohol moieties of the substrates on the enantioselectivity of the reduction were investigated. The substrates having bulky ester groups gave the (R)-hydroxy esters with high enantioselectivities. A mechanism to alter the stereoselectivity of the reduction is proposed.
Clay Montmorillonite: An Efficient, Heterogeneous Catalyst for Michael Reactions of Silyl Ketene Acetals and Silyl Enol Ethers with α,β-Unsaturated Carbonyl Compounds
Authors: Kawai Motomitsu , Onaka Makoto , Izumi Yusuke
Published: July 2006

The Michael addition of silyl ketene acetals to α,β-unsaturated esters (enoates) is investigated. The reaction is catalyzed by clay montmorillonite (solid acid) most effectively among various, homogeneous and heterogeneous acid promoters. The montmorillonite-catalyzed reaction has several prominent features: (1) Not only α- or β-monosubstituted acrylates but also α,β- or β,β-disubstituted acrylates are applicable. (2) The highly regioselective 1,4-addition to a polyenoate is achievable. (3) The Michael adduct can be obtained in the form of a labile silyl ketene acetal owing to a simple work-up procedure. The Michael reaction of a silyl enol ether and silyl ketene acetals with α,β-unsaturated ketones (enones) is also described.
A Green Complex from the Reaction of a Binuclear Copper(II) Complex of 2-Hydroxy-1,4-butanediamine-N,N,N′,N′-tetraacetic Acid and H2O2
Authors: Kawata Satoshi , Iwaizumi Masamoto , Kosugi Hiroshi , Yokoi Hiroshi
Published: July 2006

Spectrophotometric studies have revealed that a green complex is formed by the reaction of a blue binuclear copper(II) complex of 2-hydroxy-1,4-butanediamine-N,N,N′,N′-tetraacetic acid and H2O2, although analogous binuclear complexes of 2-hydroxy-1,3-propanediamine- and 3-hydroxy-1,5-pentanediamine-N,N,N′,N′-tetraacetic acids are unreactive to H2O2.
Prebiotic Synthesis Obeys the Rule of Topological Charge Stabilization
Authors: Aihara Jun-ichi
Published: July 2006

Most organic molecules synthesized in primitive-Earth-simulation experiments conform to the rule of topological charge stabilization. Heteroatoms in these molecules are all located at the best sites to stabilize the conjugated systems. The situation must be the same for organic molecules formed under prebiotic conditions on primitive Earth.
Structural Study of Potassium Gallate Glasses by Mössbauer Spectroscopy and Differential Thermal Analysis
Authors: Nishida Tetsuaki , Saruwatari Setsuko , Takashima Yoshimasa
Published: July 2006

Mössbauer spectra of a series of potassium gallate (Ga2O3-based) glasses, containing 10 mol% Fe2O3 as a Mössbauer probe, consist of two types of quadrupole doublet peaks due to tetrahedral Fe3+ ions bonded with nonbridging and bridging oxygen atoms and those bonded only with bridging oxygen atoms. This indicates that all the Fe3+ ions are present at the substitutional sites of the tetrahedral Ga3+ ions constituting the skeleton of network structure. An increase in the K2O content results in an increased fraction of the FeO4 (and GaO4) tetrahedra bonded with nonbridging oxygen atom(s). A Mössbauer spectrum of 70K2O·20Ga2O3·10Fe2O3 glass consists of only one quadrupole doublet peak due to the FeO4 tetrahedra having nonbridging oxygen atom(s). This suggests that each of the Fe3+ (and also Ga3+) ions is tetrahedrally bonded with at least one nonbridging oxygen atom. Structural information obtained from the Mössbauer measurements is confirmed by DTA measurements of the gallate glasses, Tg of which shows a drastic decrease from 647 to 555 °C when the K2O content is changed from 35 to 70 mol%.
Novel Preparation of 1- and 3-Substituted Bicyclo[3.2.2]nona-3,6,8-trien-2-ones from Tropones and 2,3-Bis(methoxycarbonyl)-7-oxabicyclo[2.2.1]heptadiene by High-Pressure Cydoaddition-Thermal Cycloreversion Procedure
Authors: Tian Guan Rong , Sugiyama Shigeru , Mori Akira , Takeshita Hitoshi
Published: July 2006

The Diels–Alder adduct of tropone with 2,3-bis(methoxycarbonyl)-7-oxabicyclo[2.2.1]hepta-2,5-diene formed homobarrelenone on heating at 130 °C. Similarly prepared were 1-hydroxy-, 3-methoxy-, 1-chloro-, and 3-chlorohomobarrelenones. High-pressure cycloaddition improved the yields of the Diels–Alder adducts. In reactions of 2-methoxy- and 2-chlorotropones with the 7-oxanorbornadiene derivative, the endo-isomers were predominantly produced together with the exo-isomers.
The Polymerization of Benzene Catalyzed by a Copper(I) Chloride–Aluminium Chloride–Oxygen System
Authors: Toshima Naoki , Kanaka Keiichi , Koshirai Atsunori , Hirai Hidefumi
Published: July 2006

The polymerization of benzene to poly(1,4-phenylene) (PPP) has been done successfully using copper(I) chloride and aluminium chloride as catalysts under oxygen. Since copper(I) chloride and aluminium chloride form a double salt (aluminium copper(I) chloride, AlCuCl4) and are soluble in benzene, a high homogeneity of the reaction system has been achieved and the polymerization reaction proceeds without any evolution of hydrogen chloride. The polymerization products contained an insoluble dark brown solid and a benzene-soluble tarry mass. The solid product has been determined to be PPP by comparison with an authentic sample. The product PPP was obtained in a yield of more than 100%, based on the molar quantity of copper(I) chloride, by controlling the quantity of aluminium chloride. For example, the treatment of benzene with aluminium chloride and copper(I) chloride (20:3:1 in molar ratio) under 1 atm of oxygen at 70 °C for 24 h gave PPP in a 187% yield, based on copper(I) chloride. This reaction could be carried out by the use of oxidants other than oxygen and by the use of low-valent metal salts other than copper(I) chloride, although a copper(I) chloride–aluminium chloride–oxygen system is most suitable for the polymerization of benzene in terms of the yield of PPP and the convenience of the reaction.
Kinetics of the Interaction between DNA and Acridine Orange
Authors: Kure Naohisa , Sano Takayuki , Harada Shoji , Yasunaga Tatsuya
Published: July 2006

Both static and kinetic investigations have been performed on the interaction of calf thymus DNA with Acridine Orange (AO). The binding isotherm obtained spectrophotometrically was analyzed by a site exclusion theory and revealed the presence of two binding modes of dye molecule corresponding to intercalation and dimerization on DNA. In the kinetic experiments focusing on the intercalation mode by the temperature-jump technique, three relaxations were observed. From the analyses of both the relaxation time and amplitude, the two fast relaxations were ascribed to parallel binding reactions including a bimolecular pathway for direct transfer of dye molecule on the polymer and the slow relaxation was attributable to a conformational change of DNA molecules. The binding parameters kinetically obtained suggest that 80% of bound AO is in intercalated form and the remainder is in partially intercalated one as an external bound form.
Solvation of Alkylbenzenes Studied by Photoelectron Emission Spectroscopy of Organic Solutions
Authors: Nakayama To-oru , Watanabe Iwao , Ikeda Shigero
Published: July 2006

The external ionization potentials for alkylbenzenes in acetonitrile and nitrobenzene have been measured by photoelectron emission spectroscopy to determine electronic polarization energies and reorganization energies. The polarization energy is used to discuss the solvation structure of alkylbenzene. The solvation behavior of alkylbenzene is found to be different from that of butylamine, previously reported. We have obtained the evidence of the approach of solvent molecules to the plane of benzene ring.
Incommensurate Phase Transitions and Anomalous Lattice Heat Capacities of Biphenyl
Authors: Saito Kazuya , Atake Tooru , Chihara Hideaki
Published: July 2006

Heat capacities of crystalline biphenyl were measured between 3 and 300 K by adiabatic calorimetry and some thermodynamic functions including the calorimetric standard entropy were tabulated. Thermodynamic properties of the successive phase transitions were determined; for the twist transition at (40.4±0.2) K, ΔtrsH=(5.02±0.08) J·mol−1 and ΔtrsS=(0.129±0.003) J·K−1·mol−1, and for the lock-in transition at (16.8±0.1) K, ΔtrsH=(0.15±0.02) J·mol−1 and ΔtrsS=(0.009±0.001) J·K−1·mol−1. Anomalously large heat capacities at low temperatures were analyzed based on lattice dynamics calculation, and the crossover of the low temperature heat capacities of biphenyl and p-terphenyl was attributed to the greater activity of the twisting mode in biphenyl. The relation of the bond flexibility to the incommensurability is discussed through the comparison of the low temperature heat capacities of biphenyl, p-terphenyl, and 4,4′-difluorobiphenyl.
Heats of Solution and Viscosity B Coefficients for Some Cyclic Mono- and Bis(quaternary ammonium) Salts
Authors: Tamaki Kunio , Kitazawa Takeshi , Asada Misako
Published: July 2006

Heats of solution and viscosity B coefficients, for cyclic mono(quaternary ammonium) salts, (CH3)2N(CH2)nBr (n=4–6) and cyclic bis(quaternary ammonium) salts, (Remark: Graphics omitted.) (n=1–3) in water were measured, and the effect of structural changes in the solvent water upon the dissolution of both series of electrolytes is discussed.
Natural-Abundance Oxygen-17 Magnetic Relaxation in Aqueous Solutions of Carbohydrates
Authors: Uedaira Hisashi , Ikura Mitsuhiko , Uedaira Hatsuho
Published: July 2006

The spin-lattice relaxation times, T1, of H217O have been measured for aqueous solutions of several pentoses, hexoses, di-, and trisaccharides as a function of the concentration at 25 °C. The coordination numbers, nh, and the rotational correlation times, τch, of water molecules around the sugars were estimated and compared with that of pure water, τc°. The value of τch⁄τc°=4.10 for glucose is largest, while that of τch⁄τc°=2.82 for ribose is the smallest, among these sugars. The value of nh (τch⁄τc°−1) was defined as the dynamic hydration number. The dynamic hydration numbers showed a good correlation with the mean number of the equatorial OH groups and the limiting diffusion coefficients.
A New Method for the Calculation of the Sextet Polynomial of Unbranched Catacondensed Benzenoid Hydrocarbons
Authors: Gutman Ivan , Cyvin Sven J
Published: July 2006

A method for the calculation of the sextet polynomial of unbranched catacondensed benzenoid molecules is proposed. It requires the multiplication of a small number of 2×2 matrices and is therefore very simple.
The Ei Reaction of Substituted threo- and erythro-1-Phenylethyl Phenyl Sulfoxides
Authors: Yoshimura Toshiaki , Tsukurimichi Eiichi , Iizuka Yukihiko , Mizuno Hironobu , Isaji Hiroshi , Shimasaki Choichiro
Published: July 2006

Substituted (RS,SR)-1-phenylethyl phenyl sulfoxides (threo) (XC6H4S(O)CH(CH3)C6H4Y) and some substituted (RR,SS)-sulfoxides (erythro) were prepared and kinetic investigation for the thermal decomposition was carried out at 80.0, 90.0, and 100.0 °C in dioxane. Hammett plots for threo-XC6H4S(O)CH(CH3)C6H5 gave positive ρ-values (ρX=0.60–0.64 at three temperatures), while those for threo- and erythro-C6H5S(O)CH(CH3)C6H4Y snowed V-shape lines with bottoms at the m-OCH3 substituent though the effects of the substituents are small. Meanwhile, large kinetic isotope effects for threo- and erythro-C6H5S(O)CH(CD3)C6H4Y (Y=H, p-OMe, m-Cl) (kH⁄kD=4–6) were observed at all temperatures. The activation energies were in the range of 104–121 kJ mol−1 for all sulfoxides, while the activation entropies were relatively large (7–37 J K−1 mol−1) and were correlated with Hammett σ-values to give small negative trend. Reactions of all erythro-isomers examined were 2–3 times faster than those of the corresponding threo-isomers. From these results, it is suggested that the pyrolysis of 1-arylethyl aryl sulfoxides proceeds via a concerted mechanism in which the transition state is variable from an El-like to a conjugated one. In the latter transition state, conjugation of the phenyl group bearing the electron-withdrawing substituent with the developing π-bond electron acidifies the β-proton.
The Synthesis and Chemical Reaction of Magnesium and Calcium Bis(phosphorodiamidates) with Acids
Authors: Sato Shoji , Takayanagi Takao , Watanabe Makoto
Published: July 2006

Magnesium bis(phosphorodiamidate) hexahydrate and calcium bis(phosphorodiamidate) dihydrate were made by adding an aqueous solution of magnesium chloride or calcium chloride to a sodium phosphorodiamidate solution. These phosphorodiamidates reacted with the water of crystallization and/or adsorbed water to produce phosphoramidate and orthophosphate. They also reacted with HCl gas, acetic acid, and oxalic acid to make polyphosphates and phosphates with amino and/or imino groups. Several typical reactions are as follows:

(Remark: Graphics omitted.)

where M and HA stand for alkaline earth metal and acid respectively.
The Phase Transition of Quaternary Fluoroalkyl Halide Salts of 1,4-Diazabicyclo[2.2.2]octane
Authors: Terada Tohru , Nogami Takashi , Shirota Yasuhiko
Published: July 2006

The solid–solid phase transition of quaternary halide salts of 1,4-diazabicyclo[2.2.2]octane (DABCO) was investigated by DSC, Raman spectroscopies, and the measurements of the ionic conductivity of the halide anions. The DABCO salts studied are classified into two; one is the salt possessing both fluoroalkyl and alkyl groups, and the other the ones possessing the same fluoroalkyl groups at both ends of the molecule. The former molecule exhibited a gradual increase of the ionic conductivity above the transition temperature. The ionic conductivity of the former molecule was higher than that of the latter molecules and the symmetric quaternary alkyl halide salts of DABCO. These facts were explained by a spacer effect of the fluoroalkyl group. The temperature dependence of the Raman spectra of the former salt established that the fluoroalkyl group was much more rigid than the alkyl group, and that the molecular movement took place mainly at the alkyl group and the DABCO portion in the high temperature phase. One of the latter type of molecules exhibited a conductivity jump around the transition temperature.
Hexacarbonylmolybdenum(0)-Induced Dechalcogenization of Allylic Sulfides, Sulfones, and Selenides: Nucleophilic Substitution and Reductive Dechalcogenization
Authors: Masuyama Yoshiro , Yamada Kohji , Shimizu Soh-hei , Kurusu Yasuhiko
Published: July 2006

Hexacarbonylmolybdenum(0)-induced dechalcogenization of allylic sulfides I, sulfones II, and selenides III in refluxing dioxane, which led to nucleophilic substitutions with carbon nucleophiles. Attack of the relatively bulky nucleophile, 2-ethoxycarbonyl-2-sodiocyclopentanone occurred regioselectively at the less substituted end of the allyl unit after the dechalcogenization to give only one isomer. Attack of diethyl sodiomalonate to I and III occurred preferentially at γ-position, and that to II occurred preferentially at the more substituted end of the allyl unit after the desulfonylation. In the absence of the carbon nucleophiles, treatment of I, II, and III with Mo(CO)6 in refluxing dioxane caused reductive dechalcogenization. Addition of H2O accelerated the reductive dechalcogenization.
Synthetic Photochemistry. LII. Substituent Effects of a Bromine Atom on the High-Pressure Cycloaddition between 1-Acetyl-7-bromocyclohepta[b]pyrrol-2(1H)-one and 2,3-Bis(methoxycarbonyl)-7-oxanorbornadiene and the Photorearrangement of 2-Acetyl-9-bromo-2-azatricyclo[6.2.2.01,5]dodeca-4,6,9,11-tetraen-3-one
Authors: Tian Guan Rong , Mori Akira , Takeshita Hitoshi
Published: July 2006

A high-pressure cycloaddition reaction of 1-acetyl-7-bromocyclohepta[b]pyrrol-2(1H)-one and 2,3-bis(methoxycarbonyl)-7-oxanorbornadiene and a further thermolysis of [4+2] cycloadducts gave 2-acetyl-9-bromo-2-azatricyclo[6.2.2.01,5]dodeca-4,6,9,11-tetraen-3-one, which was photorearranged to 9-methylenebarbaralane and 5-methylenetricyclo[4.3.0.02,9]nonadiene derivatives. The product distribution of the photolysis was altered by a bromine atom.
Photochromism of 4-Oxazolyl Fulgides
Authors: Suzuki Hisao , Tomoda Akihiko , Ishizuka Mitsuo , Kaneko Akira , Furui Masami , Matsushima Ryoka
Published: July 2006

The thermal and photochemical stabilities of 2-[1-(2-phenyl-5-methyl-4-oxazolyl)]alkylidenesuccinic anhydrides (1) and (2) were studied. These compounds showed good thermal stabilities in PMMA film and low photochemical fatigue (PF≤0.03% /cycle) in a dilute toluene solution in the presence of air, compared with 3-furyl fulgide (3). Although in PMMA film the photochemical fatigue resistance property of the fulgides was poor, in comparison with that in solution, the addition of an organo-nickel stabilizer improved the property.
Aryliminodimagnesium Reagents. XV. Condensation with Nitrobenzene. Formation of Unsymmetrical Azobenzenes Favored by Long-Chain p-Alkoxy-Substituted Reagents
Authors: Okubo Masao , Matsuo Koji , Yamauchi Akira
Published: July 2006

In the reaction of p-MeC6H4N(MgBr)2 with p-alkoxynitrobenzene, no effect of alkoxyl chain length on the relative yields of azoxy and azo products was observed. In contrast, in the reaction of p-alkoxy-C6H4N(MgBr)2 with p-nitrotoluene, C12- and C18-alkoxyl chains led to the corresponding unsymmetrical azobenzenes in unexpectedly high yields. This result, arising from efficient condensation and deoxygenation processes, was explained in terms of cooperation of reagent molecules through their aggregation assisted by a novel tying effect of their long chains.
A NEW ROUTE FOR THE SYNTHESIS OF TETRAALKYLUREAS. THE REACTION OF CARBON MONOXIDE WITH SELENIUM AND DIALKYLAMINES
Authors: Kondo Kiyoshi , Sonoda Noboru , Yoshida Kokichi , Koishi Masafumi , Tsutsumi Shigeru
Published: July 2006

The reaction of carbon monoxide with selenium and dialkylamines followed by oxidation with molecular oxygen at 0°C gave bis(N,N-dialkylcarbamoyl) diselenide, pyrolysis of which yielded bis(N,N-dialkylcarbamoyl) selenide and tetraalkylurea.
THE COEXTRACTION OF WATER WITH ALKALI AND ALKALINE EARTH METALS HEXANITRODIPKENYLAMINATES AND ANALOGOUS AMINATES
Authors: Kawasaki Mikio , Tôei Kyoji , Iwachido Tadashi
Published: July 2006

Alkali and alkaline earth metal salts of hexyl (2,4,6,- 2′,4′,6′-Hexanitrodiphenylamine), α-hexyl (N-(2,4,6-trinitrobenzo)-2,4-dinitro-1-naphthylamine), and thiohexyl (1,3,7,9-Tetranitrophenothiazine-5-oxide) were extracted into nitrobenzene. The water in the nitrobenzene solution was determined by means of the Karl–Fischer method. It was found that the water content in the extract was greater than that in nitrobenzene which did not contain these salts. The behavior of water in nitrobenzene phase was discussed on the basis of absorption spectra in near infrared region and of proton magnetic resonance spectra.
TRANSFERENCE OF WATER TO THE NITROBENZENE PHASE FOR THE EXTRACTION OF TRIS(1,10-PHENANTHROLINE)IRON(II) CHELATE SALTS
Authors: Yamamoto Yuroku , Tarumoto Tsunehiko , Tarui Takao
Published: July 2006

The amount of water transferred to the nitrobenzene phase was determined for the extraction of ion pairs of tris(1,10-phenanthroline)iron(II) with halide and pseudohalide anions. The results were consistent with the number of water of crystallization of these salts.
THE CRYSTAL STRUCTURE OF PHENANTHROLINIUM PENTACHLOROMANGANATE(III), (phenH2)(MnCl5)
Authors: Matsui Masanori , Koda Shigetaka , Ooi Shun′ichiro , Kuroya Hisao , Bernal Ivan
Published: July 2006

It has been established by X-ray analysis that the crystal of phenanthrolinium pentachloromanganate(III) contains (phenH2)2+ and square-pyramidal (MnCl5)2−.
STRUCTURE AND REACTIVITY OF OLIGONUCLEOTIDES. PART I KINETICS OF THE NON-ENZYMATIC TRANSPHOSPHORYLATION OF ADENYLYL-(3′-5′)-ADENOSINE 3′-PHOSPHATE AND OTHER DINUCLEOTIDES
Authors: Koike Tatsuro , Inoue Yasuo
Published: July 2006

Kinetics of the non-enzymatic transphosphorylation of several diribonucleotides have been studied. First-order rate constants for the reactions, which are acid-base-catalyzed, have been obtained. Base-sequence and base composition dependent nature of rates is discussed.