bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure of Platinum Particles Deposited on Titanium Dioxide (110) Surface Studied by X-Ray Photoelectron Diffraction
Authors: Tamura Koji , Owari Masanori , Nihei Yoshimasa
Published: July 2006

Platinum atoms deposited on a TiO2 (110) surface were studied by X-ray photoelectron diffraction, and the structure of the platinum particles was clarified. It was found that after annealing at 823 K for 30 min the platinum particles coalesced and that the structural model of platinum particles based on the (111) surface of the fcc crystal explained the experimental XPED patterns very well.
Proton and Carbon-13 NMR Study of Dimer Dianions Produced from 1,1-Diphenylethylene Derivatives
Authors: Yokoyama Yukihiro , Ushio Masahiro , Goto Kenji , Takaki Mikio , Takahashi Kensuke , Asami Ryuzo
Published: July 2006

1H and 13C NMR spectra have been observed for the carbanions produced from 1,1-diphenylethylene derivatives. Among five precursors, three have been reduced to corresponding dimer dianions in contact with alkali metal in THF; however, the rest could not be dimerized. Failure in dimerization is controlled by a steric effect of substituents at the 2-position. DNMR measurements were also carried out for 1,1-di-p-tolylpropene dimer dianions. The results are discussed in terms of two internal rotations around the bonds between the C1 and C2, and the C1 and Ci atoms.
Effect of Polyethylene Glycol Monoalkyl Ethers on Phase Transition Temperature of Dipalmitoylphosphatidylcholine Vesicle Membrane
Authors: Inoue Tohru , Fukushima Kohsuke , Shimozawa Ryosuke
Published: July 2006

The gel-to-liquid-crystalline phase transition temperature of a dipalmitoylphosphatidylcholine vesicle membrane was measured in the presence of polyethylene glycol monoalkyl ethers (CnEm) of various chain lengths of hydrophobic (n) and hydrophilic (m) groups. All of the surfactants, except of C12E1, depressed the transition temperature almost linearly with the concentration. The depression of the phase-transition temperature was analyzed by applying the van’t Hoff model for the freezing-point depression; also, the partition coefficients of the surfactants between bulk water and the membrane phase were estimated. Discussions were given concerning the dependence of the partition coefficients on the chain lengths of both oxyethylene and alkyl groups.
Formation of Graphite Single Crystal from Iron Solution by the Slow Cooling Method
Authors: Sumiyoshi Yoshihiro , Ushio Masumi , Suzuki Sadao
Published: July 2006

Graphite single crystals with maximum dimensions of 40 mm in diameter and 0.04-mm thick were prepared from an iron solution by a slow-cooling method. The cell parameters of the product were ao=2.462±0.002 and co=6.708±0.001 Å. A flux of 200 g of electrolytical iron and 8 g of graphite were charged in the graphite crucible. The iron melt, saturated with carbon, was slowly cooled from maximum temperatures ranging between 1800 and 2500 °C to near 1150 °C at cooling rates ranging from 5 to 30 °C min−1. Large graphite single-crystal films of better quality were formed after quick cooling rather than slow cooling. Large graphite crystal films were formed at above 1850 °C; temperatures greater than 1950 °C were needed in order to grow the crystal films with good quality. From in-situ observations through a hole, the growth of the small graphite crystals was seen to occur on the surface of the melt at about 1550 °C; these were gathered in a constant direction, initiating the incorporation of small crystals. The incorporation of the small crystals was promoted at about 1700 °C and the surface of the melt was covered with a single-crystal film. For the formation mechanism of the graphite single-crystal film, a heating process was played an important role.
Reactions of Bis(β-diketonato)platinum(II) and -palladium(II) with Diphosphines Ph2PCHRPPh2 (R=H, Me): Unexpected Formation of the Homoleptic Bis(diphenylphosphino)methanido and Related Complexes
Authors: Hashimoto Hiromasa , Okeya Seichi , Nakamura Yukio
Published: July 2006

The reactions of [M(β-dik)2] (M=Pt(II), Pd(II); β-dik=acetylacetonate (acac), dipivaloylmethanate (dpm), hexafluoroacetylacetonate (hfac) ions) with dppm (dppm=Ph2PCH2PPh2) and mdppm (mdppm=Ph2PCH(Me)PPh2) have been investigated. [M(hfac)2] complexes react with dppm to afford the stable cationic complexes, [M(dppm)2](hfac)2. By contrast, [M(acac)2] complexes react to give the homoleptic bis(diphenylphosphino)methanido complexes, [M(Ph2PCHPPh2)2], through deprotonation of dppm by the displaced acac anions. The analogous complexes, [M(Ph2PC(Me)PPh2)2], are obtained using mdppm, instead of dppm. A complete reaction scheme leading to these products is proposed, based on the IR and 1H, 13C, and 31P NMR spectral data. Some consideration is given to the dependence of these reactions on the metals and the β-diketonate ligands, employed.
Syntheses, and Crystal and Molecular Structures of [Enneakis(chloroacetato)tetrakis(dimethyl sulfoxide)trineodymium(III)], [Nd3(ClCH2CO2)9{(CH3)2SO}4], and of the Isomorphous Lanthanum(III) and Praseodymium(III) Salts
Authors: Sugita Yoshihiko , Ouchi Akira
Published: July 2006

The crystal and molecular structures of the chloroacetato–dimethyl sulfoxide (dmso) mixed complex of neodymium(III) indicated in the title were determined by the single-crystal X-ray diffraction method. The crystal is monoclinic, space group P21⁄n, a=21.106(21), b=15.871(8), c=15.748(7) Å, β=93.29(5)°, Z=4 (including 12 metal atoms in a unit cell). There are three kinds of crystallographically independent metal atoms, Nd(1), Nd(2), and Nd(3): Nd(1) and Nd(3) are ennea-coordinated (approximately tricapped trigonalprism geometry), and Nd(2) is deca-coordinated (approximately bicapped square-antiprism geometry) including a slightly long M–O bonding. All dmso molecules are directly coordinated to the metal atoms as unidentate, while all the carboxylate ions bridge metal atoms acting as bidentate or tridentate ligands. The bridging atoms are arranged in a chain which is approximately formed along the [101] axis. Also, the isomorphous lanthanum(III) and praseodymium(III) complexes were obtained and their structures were elucidated.
Thermal and Photochemical Reactions of 10-Methyl-9-phenylacridinium Chloride in Alcohols
Authors: Zhou Bin , Kano Koji , Hashimoto Shizunobu
Published: July 2006

The photoreduction of 10-methyl-9-phenylacridinium chloride in methanol containing K2CO3 involves the nucleophilic addition of methanol to the 9-position of the acridinium cation, the photoinduced heterolysis of the methanol adduct, and the hydride transfer from the alkoxide anion to the acridinium cation in the nonrelaxed ground states to give 9,10-dihydro-10-methyl-9-phenylacridine.
Synthesis of Cyclic Polysulfides. Reactions of Dithiols and Related Compounds with Elemental Sulfur in Liquid Ammonia
Authors: Sato Ryu , Saito Satoru , Chiba Hiroshi , Goto Takehiko , Saito Minoru
Published: July 2006

Many cyclic polysulfides, i.e., benzopentathiepins (3a–d), 6H-1,2,3,4,5-benzopentathiocin, 5H-1,2,3,4-benzotetrathiepin, 3H-1,2-benzodithiole, 1,5-dihydro-2,3,4-benzotrithiepin, 1,4-dihydro-2,3-benzodithiin, naphtho[1,8-cd]-1,2-dithiole, 1,2,3-trithiane, 1,2-dithiane, 2,3,4,5-tetrathiabicyclo[4.4.0]decane, and 2,3,4,5,6-pentathiabicyclo[5.4.0]undecane, were synthesized in high yields by new reactions of their corresponding dithiols and related compounds, 1,3-benzodithiole-2-thiones (5) and 1,3-dithiolane-2-thione, with elemental sulfur in liquid ammonia at ambient temperature. In the synthesis of 3a–d from 1,2-benzenedithiol or 5, considerable increase in the product yield was observed upon adding 1,3-dinitrobenzene to the solvent used in work-up.
Hydrolytic Metalloenzyme Models. Effects of AOT Reverse Micelles on the Hydrolysis of p-Nitrophenyl Picolinate Catalyzed by Zn2+ and Cu2+ Complexes of N-Alkyl-2-hydroxymethylimidazoles
Authors: Fujita Tsunehisa , Inaba Yoichi , Ogino Kenji , Tagaki Waichiro
Published: July 2006

The catalytic effects of bivalent metal ion (Zn2+ and Cu2+) complexes of N-alkyl-2-hydroxymethylimidazoles on the hydrolysis of p-nitrophenyl picolinate (PNPP) have been studied kinetically in the reverse micelles of AOT/hexane/water at 25 °C. The results were compared with those obtained in the non-micellar aqueous media and aqueous micelles. The hydrolysis was observed to occur through the acyl group transfer from PNPP to the ligand hydroxyl group in both cases of Zn2+ and Cu2+ ions and in all three non-micellar and micellar systems. However, the ligand:metal ion ratio in the kinetically active complexes was found to differ significantly in the three systems: there seems to exist general trends of 1 : 1, 2 : 1, and 4 : 1 stoichiometry in the ligand:metal ion ratio, depending on non-micellar aqueous media, aqueous micelles and reverse micelles, respectively. It was also noticed that the hydrolysis is always faster in micellar systems than in non-micellar aqueous media. Furthermore, a lipophilic ligand (N-dodecyl, Lig-12) was found to be more active than a hydrophilic ligand (N-methyl, Lig-1) under two micellar conditions.
Synthesis of Oligoribonucleotides by Use of 4,4′,4″-Tris(acyloxy)trityl Groups for Protection of the 6-Amino Group of Adenosine
Authors: Sekine Mitsuo , Iwase Reiko , Masuda Narihiro , Hata Tsujiaki
Published: July 2006

Two kinds of substituted trityls, i.e., 4,4′,4″-tris(benzoyloxy)trityl (TBTr) and 4,4′,4″-tris(p-anisoyloxy)trityl (TAnTr), have been examined as protecting groups of the amino group of adenosine in oligoribonucleotide synthesis. The former was used for a 3′-terminal adenosine unit and the latter was introduced into an building block of internal adenosine. These protecting groups were successfully applied to the liquid-phase synthesis of pGUA and pGUAUUA which were the 5′-terminal oligoribonucleotide fragments of brome mosaic virus mRNA 4.
Synthesis and Properties of Novel Analogs of Viologen
Authors: Kawashima Toshihide , Shiomi Yutaka , Tohda Yasuo , Ariga Masahiro , Mori Yutaka , Sakata Yoshiteru , Misumi Soichi
Published: July 2006

Several viologen analogs having good coplanarity were synthesized and their redox potentials were measured by cyclic voltammetry.
Preparation and Properties of Pyridine-Analogue of TCNQ Dianion Salt
Authors: Hama Yoshiyuki , Nobuhara Yukikazu , Aso Yoshio , Otsubo Tetsuo , Ogura Fumio
Published: July 2006

Bis(tetrapropyl- and tetrabutylammonium) 1,1′-(2,5-pyridinediyl)bis[dicyanomethanide] (4a and 4b) were prepared in order to investigate the properties of pyridine-analogue 3 of TCNQ as a new electron acceptor and its complexation with TTF. Although 3 was not isolated, the cyclic voltammetry of the salt 4 indicated that 3 was a stronger electron acceptor than TCNQ. The charge-transfer complex of TTF and 3 was prepared by mixing TTF with 3 which was generated in situ from the electrolytic oxidation of 4 or from the oxidation of 2,5-bis(dicyanomethyl)pyridine, a precursor of 4, with hydrogen peroxide. It consisted of 1 : 1 composition of donor and acceptor and showed a high electrical conductivity of 19 S cm−1. The 2 : 1 complex was prepared by metathesis of (TTF)3(BF4)2 and 4, and also highly conductive.
The Conformational Studies of 4,7,10-Trioxa-1,13-dithia[13](1,1′)ruthenocenophane and Its PdCl2 Complex by X-Ray Analyses
Authors: Akabori Sadatoshi , Sato Sadao , Kawazoe Kayoko , Sato Masaru , Habata Yoichi
Published: July 2006

Dichlorobis(4,7,10-trioxa-1,13-dithia[13](1,1′)ruthenocenophane)palladium(II) (6) was obtained by the reaction of 4,7,10-trioxa-1,13-dithia[13](1,1′)ruthenocenophane (5) with dichlorobis(acetonitrile)palladium(II) in 72% yield. The crystal structures of the complex 6 and its metal free ligand 5 were determined by the X-ray method. The crystal data: 5, monoclinic, P21⁄a, a=18.783(2), b=7.895(1), c=12.892(1) Å, β=93.53(1)°, U=1908.2 Å3, Z=4, Dc=1.58 g cm−3, μ(Mo Kα)=10 cm−1. 6, triclinic, P\bar1, a=13.956(2), b=9.174(1), c=8.770(1) Å, α=86.61(1), β=75.54(1), γ=94.37(1)°, U=1080.6 Å3, Z=2, Dc=1.94 g cm−3, μ(Mo Kα)=20 cm−1. The Pd atom of 6 bonded to the two sulfur atoms of the ligand and the torsion angle (69.2°) around the z-axis of the ruthenocenophane nucleus in the metal-free ligand is much larger than the corresponding one (0.4°) in the complex. These results are completely opposite of the case of 1,4,7,10-tetrathia[10](1,1′)ruthenocenophane and its Pt complex. Furthermore, the intramolecular atomic distance (3.697 Å) between the Ru and Pd atoms in 6 suggests the absence of the Ru–Pd dative bond.
Conductometric Determination of Some Metal Ions Using Oxine as Reagent
Authors: Zaki Mohamed Tarek Mohamed , Hanna Wageh Georgy , Fawzy Mohamed Hossam
Published: July 2006

A simple and sensitive conductometric method for the determination of copper(II), iron(II) and (III), aluminum(III), chromium(III), gold(III), platinum(IV), vanadyl, zirconyl, and uranyl ions with oxine solution in ethanol–water system is described. An average recovery of 100.3% with standard deviation not exceeding 0.4% is observed. The effect of solvent, shape of titration curves and molar ratio of the chelates are studied. The proposed method shows good agreement with the conventional EDTA titration using metallochromic indicators. The advantage over the conventional method is discussed.
Phosphorescence Excitation Spectra in the Singlet–Triplet Absorption Region of Pyrazine and Pyrimidine Vapors
Authors: Fujita Masahisa , Ohta Nobuhiro , Takemura Takeshi , Baba Hiroaki
Published: July 2006

Phosphorescence excitation spectra in the S0→T1 absorption region of pyrazine and pyrimidine have been observed in the vapor phase at room temperature. In pyrimidine vapor, the origin of the S0→T1 transition has been determined to be at 350.42 nm, and the T1 state is assigned to the nπ* state.
Chemistry of Germanium Atoms. III. Reactions of Thermally Evaporated Germanium Vapor with Hydrogermanes
Authors: Mochida Kunio , Yoshida Yasuhiro
Published: July 2006

Thermally generated germanium atoms were found to react with hydrogermanes by insertion into germanium–hydrogen bonds. The resulting germylenes were inserted again in a germanium–hydrogen bond to form trigermanes.
A Convenient Synthesis of 3-Phenacylidenephthalides
Authors: Hori Kimihiko , Takaishi Naotake
Published: July 2006

3-Phenacylidenephthalides were prepared by the dehydration of 2-(1,3-dioxo-3-phenylpropyl)benzoic acids, obtained in turn by the condensation of phthalic anhydride with acetophenones.
Novel and Convenient Synthesis of Dioxaphospholes
Authors: Singh Maya Shanker , Mehrotra Kailash Nath
Published: July 2006

Treatment of 1,2-diketones 1a–d with sodium in dry THF followed by addition of dry phenyl and ethyl phosphorodichloridate gave 2-phenoxy- and 2-hydroxy-4,5-diaryl-1,3,2-dioxaphosphole 2-oxides, respectively.
Dielectric Losses of Dehydrated Na11-ZK4 and K3Na8-ZK4 Zeolites
Authors: Ohgushi Tatsuo , Nonaka Kenji , Watanabe Tsuyoshi
Published: July 2006

Dielectric properties of completely dehydrated Na11-ZK4 and K3Na8-ZK4 zeolites were studied. A relaxation loss peak and a loss in the lower frequency region were observed in both zeolites. The relaxation losses were assigned to the jump of a cation from the 8-ring site to the 4-ring site. The losses in the lower frequency region were attributed to a cation movement beyond the unit cell dimension.
Structure Dependence in the Hydrogenation of Acetylene over Columnar Pd Film
Authors: Tamaki Jun , Imanaka Toshinobu
Published: July 2006

Pd films prepared by the UHV RF sputtering system had the tapered columnar structure as observed using SEM. The microstructure of the films changed with the film thickness. This affected the hydrogenation of acetylene. The Pd films which showed the strong (220) intensity in XRD exhibited the high ethylene selectivity.
Proton Magnetic Relaxation and Molecular Motion in Crystalline Tetramethylsilane
Authors: Hasebe Tooru , Nakamura Nobuo , Chihara Hideaki
Published: July 2006

The molecular motion in the three modifications of tetramethylsilane was studied by the spin-lattice relaxation time measurements. The activation parameters for the methyl group reorientation, overall molecular tumbling, and the molecular self-diffusion were determined in each phase. A possible correlation between these parameters and the stability of the plastic phase was pointed out.
Improvement in Flash Chromatography
Authors: Naruta Yoshinori , Uemori Hitoshi , Fukumoto Masami , Sugiyama Haruhiko , Sakata Yoshitsugu , Maruyama Kazuhiro
Published: July 2006

Optimum and higher resolution in flash chromatography (FC) has been realized with 20–40 μm silica gel, which gives 1.4–1.9 times larger theoretical plate numbers, than the reported one, 40–63 μm. A new FC tube is proposed and the combination of quartz-made chromatographic tube and silica gel with fluorescent indicator is conveniently used for the preparative separation of colorless but UV absorbing compounds.
Selective Conversion of 2-Mercaptoalkanols to Thiirans with Orthocarbonates
Authors: Takata Toshikazu , Endo Takeshi
Published: July 2006

Tetraalkyl orthocarbonates 1 were demonstrated to serve as potent cyclodehydrating agents for 2-mercaptoalkanols 2 to give the corresponding thiirans in good yields in acid-catalyzed reactions in aprotic solvents. Effects of catalysts, solvents, and alkyl substituents of 1 were examined. Activity of the acid catalysts depended on their acidity (pKa), and the strong Lewis acid BF3·OEt2 also had high catalytic activity. Effects of solvents and alkyl substituents of 1 were little observed.
New Synthesis of Penta-N,O-acetyl-Dl-validamine and Pseudo-2-amino-2-deoxy-α-Dl-mannopyranose, and Their Uronate Analogs
Authors: Ogawa Seiichiro , Suzuki Motohiro , Tonegawa Takeshi
Published: July 2006

Treatment of the hydroxy lactone derived from (±)-endo-7-oxabicyclo[2.2.1]hept-5-ene-2-carboxylic acid with hydrogen bromide–acetic acid, followed by esterification, gave 48% of ethyl Dl-(1,3,5/2,4)-5-bromo-2,3,4-trihydroxy-1-cyclohexanecarboxylate, from which Dl-validamine and pseudo-2-amino-2-deoxy-α-Dl-mannopyranose, and their uronate analogs have been synthesized as the totally acetylated derivatives.
NMR Study of Dynamics of Carboxyl Proton in Crystals of Acetylenedicarboxylic Acid and p-Nitrobenzoic Acid
Authors: Imaoka Nobuyoshi , Takeda Sadamu , Chihara Hideaki
Published: July 2006

Two kinds of motions of proton in dimeric carboxyl group were distinguished by the temperature dependence of spin-lattice relaxation times of dipolar system (T1d) and of Zeeman system (T1z) on acethylenedicarboxylic acid (ADCA) and on p-nitrobenzoic acid (PNBA) in the A2⁄a form. High temperature motion of ADCA is 180° rotation of the eight-membered ring of dimeric carboxyl group about the axis nearly parallel to the hydrogen bonds. The activation energy of this motion of ADCA is 58 kJ mol−1. The low temperature motion of ADCA and PNBA is the proton translation along the hydrogen bonds in a dimeric carboxyl group, which induces the minima of T1z and T1d at the same temperature. The activation energy derived from the high temperature slope of T1z curve is 6.9 kJ mol−1 for ADCA and 2.5 kJ mol−1 for PNBA. The low temperature slope gives a small activation energy of 1.9 kJ mol−1 for ADCA and 1.0 kJ mol−1 for PNBA. The frequency dependence of T1z in the low temperature limit was constant at low Larmor frequency. This result indicates that the translational motion of protons along the hydrogen bonds is not classical but quantum-mechanical.
Effect of Attractive Solvent–Solvent and Solvent–Solute Interactions on Partial Molal Quantities
Authors: Yoshimura Yosuke , Nakahara Masaru
Published: July 2006

The effect of the perturbation due to attractive solute–solvent and solvent–solvent interactions on the partial molal volume (PMV), entropy (PME), and enthalpy in infinitely dilute solution has been formulated on the basis of the first-order perturbation theory which comes from the van der Waals picture of liquid. PMV is found to be composed of the two compensating factors which arise from the solute–solvent and solvent–solvent attractive interactions treated as the perturbation; when the former is larger than the latter PMV becomes smaller. PME is influenced only indirectly by the attractive perturbation through the volume change due to the perturbation interactions. The limitations of the basic expressions derived are discussed in the case of large solute.
On the Reduction of N-Alkoxypyridinium Ions
Authors: Sumiyoshi Takashi , Katayama Meiseki , Schnabel Wolfram
Published: July 2006

The reduction of 1-ethoxy-2-methylpyridinium (EMP+) ions in aqueous solution at room temperature by eaq−and · CO2− was investigated in a pulse radiolysis study (irradiation with 10 ns pulses of 45 MeV electrons). For comparison, experiments with 1-methylpyridinium (MP+) and unsubstituted pyridinium (PH+) ions were carried out. With MP+ and PH+ the spectra of pyridinyl radicals were observed at the end of the pulse. In the case of EMP+ the spectrum of the pyridinyl radical was not detectable. However, a new absorption band at 340 nm was formed with a significant delay after the reduction. Therefore, it was concluded that pyridinyl radicals formed by reduction of EMP+ decompose very quickly into picoline and ethoxyl radicals. The latter add to EMP+ with a rate constant k=6×107 dm3 mol−1 s−1. The transient absorption band at 340 nm is ascribed to the adduct.
Hydrogen Formation from Water Adsorbed on Zeolite during Gamma-Irradiation
Authors: Aoki Masayoshi , Nakazato Chiyoko , Masuda Takahiro
Published: July 2006

The γ-radiolysis of water adsorbed on synthetic zeolite, MS 13X (Molecular Sieve 13X), has been investigated by the product analysis method using gas chromatography. One of the main products is molecular hydrogen, the G value of which increases with increasing amount of water adsorbed on MS 13X and reaches a first plateau (0.42) at ca. 4 mmol of water per g of MS 13X. At ca. 6 mmol g−1 of water, it resumes the increase and finally approaches a second plateau (1.2) at ca. 9 mmol g−1. The formation of hydrogen is depressed by an electron scavenger, while ammonia, a scavenger of positive hole, enhances the hydrogen formation. The result indicates that hydrogen is produced through a reaction of water with electrons generated in MS 13X. The rate constant for the reaction of electrons with water adsorbed on MS 13X is estimated to be (2.6±0.3)×108 dm3 mol−1 s−1, on the assumption that rate constants for reactions of electrons with some electron scavengers determined in liquid cyclohexane can be applied to this system.
New Synthesis, Properties, and the Formation of the Hexamer of Nickel(II) Ethanethiolate, [Ni(SEt)2]6
Authors: Yamamura Takeshi
Published: July 2006

[Ni3(SEt)8]2− reacted with water in acetone to give the known hexameric ring compound, [Ni(SEt)2]6, where SEt means CH3CH2S−. The [Ni(SEt)2]6 was oxidized electrochemically in a quasi-reversible manner at +0.60 V (vs. SCE) in CH2Cl2. 1H and 13C NMR revealed that this compound has two types of –SEt (low- and high- field types; the chemical shift discrepancy is ca. 0.4 ppm for 1H NMR), probably corresponding to the axial–equatorial configurations of the thiolate. The formation of the cyclic hexamer in CH3CN and CHCl3 in the presence of protic reagents was studied.
Simultaneous Measurement of Electrical Conductivity and the Amount of Adsorbed Oxygen in Porous ZnO
Authors: Fujitsu Satoru , Toyoda Hiroshi , Koumoto Kunihito , Yanagida Hiroaki , Chikazawa Masatoshi , Kanazawa Takafumi
Published: July 2006

Changes in electrical conductivity and the amount of adsorbed oxygen in porous ZnO were measured simultaneously in the temperature range of 200–600 °C. The saturated amount of adsorbed oxygen increased initially, went through a maximum at 500 °C, and then decreased with increasing temperature. The conductivity decreased exponentially with increase in the amount of adsorbed oxygen, which indicates that the energy barrier formed due to the chemisorbed oxygen controls the total conductivity. In a high temperature region, not only the chemisorbed oxygen, but also the oxygen diffused into the grain boundaries played important roles in changing the electrical conductivity. The diffused oxygen was examined by means of a depth profile of tracer 18O measured by SIMS. The formation of the energy barrier at the grain boundary was confirmed by current-voltage characteristic measurements.
The Cyanation of Aromatic Halides Catalyzed by Nickel(0) Complexes Generated In Situ. I. General Scope and Limitations
Authors: Sakakibara Yasumasa , Okuda Fumio , Shimobayashi Akira , Kirino Kunihiko , Sakai Mutsuji , Uchino Norito , Takagi Kentaro
Published: July 2006

The cyanation of chlorobenzene catalyzed by Ni(PPh3)n, which was generated in situ from NiBr2(PPh3)2–Zn–PPh3(Ni : Zn : P=1 : 3 : 2 molar ratio), was at first examined with various MCN (M=K, Na)–solvent systems by three procedures in order to clarify the conditions under which the reaction occurs. The effects of the systems and the procedures on the reaction were remarkable. It was observed that the cyanide ion has an inhibitory action on both the reduction of Ni(II) and the oxidative addition of the halide to Ni(0). However, when such MCN–dipolar aprotic solvent systems as KCN–HMPA, KCN or NaCN–MeCN, which give low cyanide concentrations, were used, the reaction readily took place at 50–60 °C without reducing Ni(II) prior to the addition of MCN and adding MCN slowly. Various Y-substituted chlorobenzenes, except for those with Y=o-Cl, o-CN, and m-NO2, were cyanated to give the corresponding nitriles in fair to good yields. NiBr2–PPh3 can be used in place of NiBr2(PPh3)2 if MCN is added after reduction. In addition, less reactive halides, such as o-dichlorobenzene and o-chlorobenzonitrile, were fairly smoothly cyanated by the use of NiBr2–1,1′-bis(diphenylphosphino)ferrocene.
A Search for New Synthetic Routes toward Siccanin
Authors: Kato Michiharu , Matsumura Yukio , Heima Kiyoshi , Yoshikoshi Akira
Published: July 2006

11-Acetoxy-12bα-methoxymethyl-4,4,6aα,9-tetramethyl-1,2,3,4,4aα,5,6,6a, 12aβ,12b-decahydro-12H-benzo[a]xanthene (34), which has been expected as a promising key intermediate for the synthesis of siccanin (1), was synthesized via acid-catalyzed cyclization of 1α-(2-hydroxy-6-methoxy-4-methylbenzyl)-8aα-methoxymethyl-2,5,5-trimethyl-1,4,4aα,5,6,7,8,8aα-octahydronaphthalene (13) and isomeric exo olefin 21. The phenol acetate 34, however, was so resistant to oxidation that no corresponding 12-oxo derivative, which was expected to provide 11-acetoxy-12bα-acetoxymethyl-12-oxo-4,4,6aα,9-tetramethyl-1,2,3,4,4aα,5,6,6a,12aα,12b-decahydro-12H-benzo[a]xanthene (4) on epimerization at its C(12a) position as well as hydrofuran ring formation at the C(12) position with its angular methoxymethyl substituent, was obtained.
Asymmetric Diels–Alder Reactions of Some Chiral Dienophiles Derived from Cinchona Alkaloids
Authors: Suzuki Hideo , Mochizuki Koichi , Hattori Tatsuya , Takahashi Noriyuki , Tajima Osamu , Takiguchi Toshio
Published: July 2006

Acrylates, crotonate, and fumarates derived from cinchona alkaloids were easily prepared. The highly re-facial selective additions of the dienophiles derived from cinchonidine or quinine to some dienes were achieved in the presence of SnCl4. Similarly, si-facial selective additions were also achieved by the use of cinchonine instead of cinchonidine or quinine as a chiral auxiliary alcohol with equal ease. The inverse diastereofacial selectivity was observed by the use of TiCl4 instead of SnCl4 as a Lewis acid in the case of the reaction of the acrylates cited above with cyclopentadiene. It was suggested by the infrared spectra of the dienophile–SnCl4 complexes and by some circumstantial evidence that in the complexes, SnCl4 coordinates with the oxygen atom of the C–O bond (not C=O bond) and probably also with the nitrogen atom of the quinuclidine framework to form a rigid five-membered ring structure.
Polymerization of Diene-Containing Lipids as Liposomes by Radical Initiators. 6: Polymerization of 1,3-Bis(2,4-octadecadienoyl)-rac-glycero-2-phosphorylcholine
Authors: Takeoka Shinji , Hasegawa Etsuo , Ohno Hiroyuki , Tsuchida Eishun
Published: July 2006

1,3-Bis(2,4-octadecadienoyl)-rac-glycero-2-phosphorylcholine (1,3-DPC), polymerizable lipid which contains diene groups in both 1- and 3-acyl chains, was polymerized as liposomes in an aqueous medium. Polymerization was initiated by water-insoluble azobis(isobutyronitrile) (AIBN) or water-soluble azobis(2-amidinopropane) dihydrochloride (AAPD). AIBN was mixed with the monomeric lipids and the mixture was dispersed in an aqueous medium by sonication to facilitate transfer of AIBN into monomeric lipid liposomes. On the other hand, AAPD was simply added to the liposome suspension. The 1,3-DPC liposomes were easily polymerized by the addition of either water-soluble AAPD or water-insoluble AIBN to give polymerization conversion of over 80% in both cases. No selective polymerization of diene groups in the different acyl chains was found in 1,3-DPC liposomes whereas the selective polymerization was clearly seen in 1,2-bis(2,4-octadecadienoyl)-sn-glycero-3-phosphorylcholine (DODPC). Polymerized 1,3-DPC liposomes were not soluble in organic solvent suggesting the formation of crosslinked bilayer structure. The obtained results suggested that the diene groups in both 1- and 3-acyl chains were almost equivalent and located in the interface between an aqueous phase and hydrophobic region. Polymerized liposomes thus prepared were stable against heating, detergent attack and even methanol washing. Copolymerization of mixed liposomes composed of 1,3-DPC and DODPC (5:1) revealed that the AIBN or AAPD initiated polymerization conversion of DODPC reached about 68%. 1,3-DPC is considered to be radical propagation transfer between diene groups in 1- and 2-acyl chains of DODPC during polymerization.
The 2- or 6-(α-Hydroxyalkyl- and α-Oxoalkyl)-5,8-dimethoxy-1,4-naphthoquinones from the Oxidative Demethylation of 2-(α-Hydroxyalkyl- and α-Oxoalkyl)-1,4,5,8-tetramethoxynaphthalenes with Cerium(IV) Ammonium Nitrate, and the Further Demethylations to Naphthazarins
Authors: Tanoue Yasuhiro , Terada Akira
Published: July 2006

Oxidative demethylation of 2-(α-hydroxyalkyl- and α-oxoalkyl)-1,4,5,8-tetramethoxynaphthalene with (NH4)2Ce(NO3)6 gave two isomeric dimethoxynaphthoquinones: 2-substituted and 6-substituted 5,8-dimethoxy-1,4-naphthoquinones. Further demethylations of the former isomers to the corresponding dihydroxynaphthoquinones required an AgO–40%HNO3 reagent, while the latter isomers needed AlCl3 as the demethylation reagent. Some comments regarding the mechanism of these oxidative demethylations with (NH4)2Ce(NO3)6 are given.
An Observation on Carboxylation of 4H-Cyclopenta[def]phenanthrene
Authors: Minabe Masahiro , Isozumi Keisuke , Kawai Ken-ichi , Yoshida Masaaki
Published: July 2006

Photocarboxylation of 4H-cyclopenta[def]phenanthrene by carbon dioxide in the presence of N,N-dimethylaniline in dimethyl sulfoxide afforded 8,9-dihydro-4H-cyclopenta[def]phenanthrene-8- and 2-carboxylic acid, and 4H-cyclopenta[def]phenanthrene-8-carboxylic acid. These acids were derived into methyl-4H-cyclopenta[def]phenanthrenes.
Conformational Analysis of Methacrylates by IR and 1H NMR Spectroscopies
Authors: Yashima Eiji , Okamoto Yoshio , Hatada Koichi , Kageyama Hiroyuki , Kasai Nobutami
Published: July 2006

The molecular structures of α-methylbenzyl methacrylate, 1,2-diphenylethyl methacrylate, α-t-butylbenzyl methacrylate, 1,2,2,2-tetraphenylethyl methacrylate, diphenylmethyl methacrylate, and 1,1-diphenylethyl methacrylate in solution were investigated by means of IR spectroscopy and 1H NMR spectroscopy using a lanthanoid-induced chemical shift (LIS) reagent [Eu(fod)3] by reference to X-ray analysis data. The preferred conformation between the C=C double bond and the C=O group was estimated to be s-cis in solution. The conformation of ester groups of α-substituted benzyl methacrylates in toluene depended upon the α-substituent and the temperature. On the basis of structural data, the mechanism of the highly enantiomer-selective polymerization of racemic methacrylates with a (−)-sparteine-Grignard reagent complex is discussed.
Flavin Activation by Intramolecular Acid Catalysis at N(1) Position
Authors: Shinkai Seiji , Kawanabe Sayuri , Kawase Akito , Yamaguchi Toshiro , Manabe Osamu , Harada Shigeharu , Nakamura Hideki , Kasai Nobutami
Published: July 2006

In order to assess the effect of intramolecular acid catalysis on the specific flavin reactivities, 3-methyl-10-(2-hydroxyphenyl)isoalloxazine (1(2OH)) and 3-methyl-10-(2-hydroxy-1-naphthyl)isoalloxazine (2(2OH)) were synthesized and the redox properties were compared with those of reference flavins such as 3-methyl-10-(2-methoxyphenyl)isoalloxazine (1(2OMe)) and 3-methyl-10-(2-methoxy-1-naphthyl)isoalloxazine (2(2OMe)). The pKa values for 1(2OH) and 2(2OH) were determined to be 7.7 and 7.0, respectively, which were lower than that of 3-methyl-10-(4-hydroxyphenyl)isoalloxazine (1(4OH): pKa 8.6). It is thus unlikely that 2′-OH and N(1) form a hydrogen bond at the initial state of the reaction (i.e., at the oxidized state). The X-ray crystallographic studies indicated that the phenyl ring makes an angle of 79.7° with the isoalloxazine ring and the 2′-OH group forms a hydrogen bond with methanol included in the crystal lattice. In acetonitrile at 30 °C 1-benzyl-1,4-dihydronicotinamide was not oxidized by 1(2OMe), 1(4OH), and 2(2OMe). On the other hand, the oxidation took place with 1(2OH) and 2(2OH) which have an acidic OH group at the 2′-position of the 10-aryl substituent. The presence of the intramolecular acid catalysis suggests that 2′-OH and N(1) can interact at least at the transition state or at the final state of the reaction (i.e., at the reduced state). In general, the oxidized flavin adopts a “planar” structure which is sterically tense while the reduced flavin adopts a “bent” structure which is sterically relaxed. As the structure of the transition state is more or less similar to the reduced form, the hydrogen-bonding interaction could increase on going from the tense initial state to the relaxed transition state. This is a novel example for acid catalysis in flavin-mediated reactions.
The Reaction of Lupane and Friedo-Oleanane Type Triterpenes with m-Chloroperbenzoic Acid
Authors: Tori Motoo , Matsuda Reiko , Sono Masakazu , Kohama Yoshihiro , Asakawa Yoshinori
Published: July 2006

Lupane-3β,28-diol, lupan-3β-ol, and friedelan-3β-ol were treated with m-chloroperbenzoic acid (mCPBA) in refluxing chloroform to afford corresponding lactones in one step, while lupane-3β,28-diyl diacetate, lupan-3β-yl acetate, and friedelan-3β-yl acetate to give hydroxylated or keto derivatives. Similar reaction of dendropanoxide with mCPBA yielded 6β-, 7β-, 21α-, and 22β-hydroxylated compounds.
The Refractive Index of Molten CaCl2–NaCl Mixtures
Authors: Igarashi Kazuo , Mochinaga Junichi
Published: July 2006

The refractive indices of molten CaCl2–NaCl mixtures were measured goniometrically with visible light at nine wavelengths and represented as a function of both the temperature and the wavelength using a modified Cauchy relation. Information on electronic polarization is also reported.
A New Synthetic Route to Aliphatic and Alicyclic Nitriles via Homolytic Desulfurization of α-(Dithiocarbamoylthio) Nitriles
Authors: Yanagawa Makoto , Moriya Osamu , Watanabe Yoshihiko , Ueno Yoshio , Endo Takeshi
Published: July 2006

Chloroacetonitrile was transformed into aliphatic and alicyclic nitriles through (dimethyldithiocarbamoylthio)acetonitrile. The key steps in the synthetic route consisted of mono- and dialkylation via sulfur-stabilized carbanion and homolytic desulfurization using tributyltin hydride.
Radical Reactions of Alkenylstannanes with S-Benzoyl Se-Phenyl Selenosulfide
Authors: Toru Takeshi , Yamada Yoshio , Maekawa Eturô , Ueno Yoshio
Published: July 2006

Free radical reactions of allyltributylstannane or 2-butenyltributylstannane with S-benzoyl Se-phenyl selenosulfide (1) gave S-allyl benzenecarbothioate or a mixture of S-2-butenyl and S-1-methyl-2-propenyl benzenecarbothioates, respectively. The reaction of tributylvinylstannane with 1 gave an addition product, whereas the reaction of tributylstyrylstannane gave an addition–elimination product.
The Electronic Spectra of 6,6′-Diamino-2,2′-bipyridine
Authors: Yamada Masaki , Araki Koji , Shiraishi Shinsaku
Published: July 2006

The lowest-energy π–π* band of 6,6′-diamino-2,2′-bipyridine (dabp) appeared at near-UV region, and was found to suffer a characteristic solvent effect. The results were discussed in terms of its electronic structure calculated by ab initio method using a STO-3G basis set.
Band Structure of DEBP(TCNQ)4
Authors: Willis Martin R , Mori Takehiko , Inokuchi Hiroo
Published: July 2006

Band structure calculations are reported for the intermediate conducting complex salt, DEBP(TCNQ)4 (DEBP: N,N′-diethyl-4,4′-bipyridinium, TCNQ: tetracyanoquinodimethane). They show that the array of TCNQs forms a two-dimensional band structure with conduction and valence band widths 0.1 and 0.03 eV respectively. Conduction in the third direction is likely to be by hopping or tunnelling. The results are consistent with the experimental observations of electrical conductivity, magnetic susceptibility and thermoelectric power.
The Crystal and Molecular Structure of Diaquadihydroxotetrakis(m-nitrobenzenesulfonato)discandium(III) in a Linear Polymeric Form, [Sc2(OH)2(O2NC6H4SO3)4(H2O)2]n
Authors: Tateyama Yoshikuni , Ohki Yoshiyuki , Suzuki Yasuo , Ouchi Akira
Published: July 2006

The crystal and molecular structures of the title complex has been determined by the single-crystal X-ray diffraction method. It is monoclinic, with the space group Pn, Z=2 (including 4 metal atoms), a=28.90(2), b=10.251(4), c=5.981(1) Å, and β=94.68(3)°. Both of the metal atoms, Sc(1) and Sc(2), have the hexa-coordinated octahedral geometry, being coordinated to four sulfonato oxygen atoms as well as to two water oxygen (Sc(1)) or to two hydroxide oxygen atoms (Sc(2)). Any pair of the neighboring metal atoms along the b-axis are bridged by two sulfonato ions, forming an infinite chain structure; however, the Sc(2)–O bond lengths (2.307(10)–2.556(19) Å; average, Sc(2)–O (sulfonate), 2.422; Sc(2)–O(OH−), 2.394 Å) are much longer than the Sc(1)–O lengths (2.031(7)–2.150(8) Å; average, Sc(1)–O(sulfonate), 2.055; Sc(1)–O(H2O), 2.122 Å).
Hydroxyalkylation and Lactone Formation from Dialkyl Malonate by Means of a EuIII/EuII Photoredox System
Authors: Ishida Akito , Yamashita Shinya , Takamuku Setsuo
Published: July 2006

A EuIII/EuII photoredox system in alcohol induced an effective hydroxyalkylation at an α-position of a dialkyl malonate. The alcohol adduct was then converted to the lactone. A step-by-step hydroxyalkylation mechanism was suggested in which the Eu ion is used as a photocatalyst and also as a condensation catalyst for the reaction of dialkyl malonates and aldehydes.
Conjugate Reduction of α,β-Unsaturated Ketones with Amphiphilic Reaction System
Authors: Nonoshita Katsumasa , Maruoka Keiji , Yamamoto Hisashi
Published: July 2006

The conjugate reduction of α,β-unsaturated ketones has been effected with amphiphilic reaction system consisting of methylaluminum bis(2,6-di-t-butyl-4-alkylphenoxide) and certain complex aluminum hydride reagent.
Crystal Structure of [Chloro[tris[(1-ethyl-1H-benzimidazol-2-yl)-methyl]amine]zinc(II)] Tetraphenylborate Acetone
Authors: Matsumoto Naohide , Akui Toshifumi , Ohyoshi Akira , Okawa Hisashi
Published: July 2006

The crystal structure of the title complex has been determined by the single-crystal X-ray diffraction method. The zinc complex has approximately a trigonal bipyramidal coordination geometry, which is different from the copper(II) complex with the same tripod ligand.
Regioselective Alkylation in the Course of Aldol Condensation under Phase-Transfer Catalytic Conditions
Authors: Gu Xue-Ping , Ikeda Isao , Okahara Mitsuo
Published: July 2006

Regio- and stereoselective alkylation in the course of aldol condensation under liquid-solid phasetransfer catalytic conditions, affording conjugated dienyl ether (5) or α-substituted β,γ-olefinic aldehyde (7) depending on the starting halides, both in good yields, was disclosed. The reaction mechanism is also discussed.
Carbon-13 NMR of N-Substituted 2,4,6-Trimethylpyridinium Salts
Authors: Salman Salman R , Hassan A H , Khayat M A R
Published: July 2006

Carbon-13 chemical shifts of twelve N-substituted, 2,4,6-trimethylpyridinium (TMP) salts were determined. The data have been used to estimate the relative ring current (RRC) of the N-substituents on the pyridinium ring.
Synthesis of New Naturally Occurring 4-Phenyl-2H-1-benzopyran-2-ones
Authors: Parmar Virinder S , Jain Rajni , Singh Suddham
Published: July 2006

5,7-Dimethoxy-4-(4-hydroxyphenyl)-2H-1-benzopyran-2-one and 5,7-dimethoxy-4-(4-methoxyphenyl)-2H-1-benzopyran-2-one, two new neoflavonoids occurring in Courtarea hexandra have been synthesized via Pechmann condensation. Attempts made to synthesize another 4-arylcoumarin, 5-hydroxy-7-methoxy-4-(2,5-dihydroxyphenyl)-2H-1-benzopyran-2-one, constituent of the same plant, led to the formation of the hitherto unknown 2-ethoxy-6-hydroxy-4H-1-benzopyran-4-one.
Liquid-Phase Dehydrogenation of Methanol with Homogeneous Ruthenium Complex Catalysts
Authors: Itagaki Hiroaki , Shinoda Sumio , Saito Yasukazu
Published: July 2006

Catalytic dehydrogenation of methanol proceeded with homogeneous ruthenium(II) complexes, yielding formaldehyde and dihydrogen as primary products under refluxing conditions of the solution. The effects of additives on the initial reaction rate were examined for lithium chloride, lithium acetate, acetic acid and ethyldiphenylphosphine. A catalyst complex, [Ru(OAc)Cl(PEtPh2)3], was deactivated gradually by the displacement of the bidentate OAc ligand with H and CO ligands during the reaction. These cis-disposed sites would be used for splitting the C–H bonds. A catalytic reaction cycle is proposed, in which such processes are included as solvolysis of the catalyst complex, β-H elimination from the OCH3 ligand and attack of acetic acid on the hydride intermediate to generate dihydrogen.
Characterization of Active Sites in Sulfided Molybdenum/ Alumina Hydrodesulfurization Catalysts
Authors: Maezawa Akinori , Kitamura Masaru , Okamoto Yasuaki , Imanaka Toshinobu
Published: July 2006

The site configuration of Al2O3-supported molybdenum sulfides catalytically active for hydrodesulfurization (HDS) of thiophene has been investigated as a function of pretreatment conditions (H2S/H2=0–0.2) by using X-ray photoelectron, laser Raman and IR spectroscopies and temperature-programmed desorption of adsorbed NO. It has been found that when MoO3/Al2O3 catalysts are presulfided with H2S/H2, MoS2-like species are formed, whereas when prereduced and subsequently sulfided during the HDS reaction, molybdenum oxide sulfides or highly dispersed amorphous molybdenum sulfides are initially produced. The turnover frequency of the HDS reaction calculated on the basis of the NO adsorption was shown to increase with decreasing dispersion degree of sulfided molyb denum. It is proposed that two kinds of NO adsorption sites are present; triply and doubly coordinatively unsaturated (cus) molybdenum sites. It is considered that both sites are catalytically active, possibly, the triply cus species being more active. It is concluded that the HDS activity of sulfided MoO3/Al2O3 catalysts is determined by the structure, dispersion and coordinative unsaturation of sulfided molybdenum.
Synthesis, Crystal Structure, and Physical Properties of the Charge-Transfer Complex Bis[benzo[1,2-c:3,4-c′:5,6-c″]trithiophene]–tetrafluorotetracyanoquinodimethan, (BTT)2(TCNQF4)
Authors: Sugano Tadashi , Hashida Takashi , Kobayashi Akiko , Kobayashi Hayao , Kinoshita Minoru
Published: July 2006

The semiconductive 2:1 charge-transfer complex between benzo[1,2-c:3,4-c′:5,6-c″]trithiophene and 2,2′-(2,3,5,6-tetrafluoro-2,5-cyclohexadiene-1,4-diylidene)bis[propanedinitrile], (BTT)2(TCNQF4), crystallizes in the monoclinic system, space group P21⁄c, with the following cell constants: a=8.893(2) Å, b=10.589(2) Å, c=18.528(4) Å, β=114.52(1)°, V=1587.5(10) Å3, Dx=1.61 g cm−3, and Z=2. The crystal structure of (BTT)2(TCNQF4) consists of stacking columns of alternating donor dyads and acceptor monads (DAD units) along the crystallographic b axis. Side-by-side sulfur-sulfur contacts shorter than the sum of the van der Waals radii were found along the axis between BTT molecules on the neighboring columns. Polarized reflectance spectra were measured with the single crystal of (BTT)2(TCNQF4) at room temperature, showing a charge-transfer band polarized parallel to the stacking direction. The degree of charge transfer was estimated to be 0.21 from the oscillator strength and the transition energy of the charge-transfer band. From this, as well as the electric and magnetic properties of the complexes and the atomic distances for TCNQF4, it was concluded that (BTT)2(TCNQF4) is a weakly ionized charge-transfer complex.
Photoinduced Extraction and Active Transport of Anions by a Triphenyl Methane Derivative
Authors: Sasaki Hiroshi , Ueno Akihiko , Osa Tetsuo
Published: July 2006

Triphenylmethane derivative leukobase (1) was converted to its cation form 2 by UV irradiation. This lipophilic cation form was stable in dichloromethane with green color (λmax=634 nm), and returns to the original colorless form of 1 when shaked with an alkaline solution. Compound 2 exhibited excellent anion extraction ability (from aqueous solution into dichloromethane) under the conditions of appropriate pH, but 1 has no anion extraction ability. Photoinduced active transport of anions across a liquid (dichloromethane) membrane was achieved by using the difference in the extraction ability between 1 and 2 together with the difference in pH between the source and receiving phases.
Asymmetric Grignard Cross-Coupling Reaction Using Chiral Ligands Derived from Carbohydrates
Authors: Iida Akihito , Yamashita Mitsuji
Published: July 2006

Chiral diphenylphosphine and diphenylphosphinite derivatives of carbohydrates such as d-glucose, d-galactose, and l-rhamnose were used as the ligand of metal catalysts for asymmetric Grignard cross-coupling reaction. Coupling of s-butylmagnesium bromide with bromobenzene was carried out in the presence of nickel or palladium chloride with the chiral ligand. The highest optical yield was observed when d-galactose ligand was used.
Selective Preferential Esterification of the Dicarboxylic Acids with Longer Carbon Chain by Diazomethane in the Presence of Dicarboxylic Acids with Shorter Carbon Chain by Adsorbing and Aligning the Acids on Alumina
Authors: Ogawa Haruo , Hiraga Nobuo , Chihara Teiji , Teratani Shousuke , Taya Kazuo
Published: July 2006

Selective monoesterification of a dicarboxylic acid with longer carbon chains by diazomethane in a mixture of dicarboxylic acids, [dodecanedioic acid (C12) plus glutaric acid (C5), adipic acid (C6), pimelic acid (C7), suberic acid (C8), or sebacic acid (C10)] was achieved by adsorbing and aligning the acids on alumina. The larger the difference in the number of carbon atoms, the higher the selectivity. In the case of the combination of C12 and C5 the highest selectivity was observed and the preferential 89% formation of the monomethyl ester of C12 was obtained in contrast to the 9% formation for the monomethyl ester of C5. Selective reactions were also observed in the case of the combination of C10 and C4, and that of C12 and trans-1,4-cyclohexanedicarboxylic acid.
A New Method of Synthesizing 7-(2-Hydroxy-5-oxo-1-cyclopentenyl)heptanoic Acid and Related Compounds
Authors: Naora Hirokazu , Ohnuki Takashi , Nakamura Asao
Published: July 2006

A useful prostanoid synthon, 7-(2-hydroxy-5-oxo-1-cyclopentenyl)heptanoic acid (3), was prepared from commercially available cyclooctanone in two steps. Nine other related cyclopentanoids which are also valuable synthons for prostaglandins were obtained from 3 in reasonable yields via several steps. The procedure is capable of generating these useful synthons on a laboratory scale.