bluuebunny/crossref_metadata_2025 huggingface dataset:
Mössbauer and DTA Studies on the Structure of Semiconducting Sodium Vanadate Glasses
Authors: Nishida Tetsuaki , Ogata Michiko , Takashima Yoshimasa
Published: July 2006

Distinct decreases in the quadrupole splitting of the tetrahedral Fe3+ ions and the Tg suggest a gradual change from the layer structure composed of the VO5 tetragonal pyramids to the chain structure composed of the VO4 tetrahedra. It is also concluded that nonbridging oxygen atoms are present in the VO4 tetrahedra.
Hydroxylation of Acetoxy-p-menthenes in the Cultured Cells of Nicotiana tabacum. Epoxidation of the Carbon–Carbon Double Bond
Authors: Hirata Toshifumi , Izumi Shunsuke , Ekida Teiji , Suga Takayuki
Published: July 2006

The process of the formation of glycols in the biotransformation of 1-acetoxy-p-menth-4(8)-ene and 8-acetoxy-p-menth-1-ene in the cultured cells of Nicotiana tabacum was examined. The formation of the glycols was found to result from epoxidation of the C–C double bond, followed by hydrolysis of the resulting epoxides.
Photochemical Reactions of Ethoxycarbonyl-Substituted Quinolines
Authors: Ono Isao , Hata Norisuke
Published: July 2006

The photochemical reactions of the quinoline derivatives substituted by an ethoxycarbonyl group at the 2-, 3-, and 4-positions of a quinoline nucleus have been investigated in several alcohols and cyclohexane. Irradiation of ethyl 4-quinolinecarboxylate (1) yielded ethyl 2-hydroxyalkyl-4-quinolinecarboxylates (4a–c) in alcohols and ethyl 2-cyclohexyl-4-quinolinecarboxylate (4d) in cyclohexane in a good yield, respectively. The photochemical reactions of ethyl 3-quinolinecarboxylate (2) showed remarkable solvent dependency. Irradiation in methanol and cyclohexane afforded a solvent-additive product, ethyl 4-hydroxymethyl-1,4-dihydro-3-quinolinecarboxylate (5a) and ethyl 4-cyclohexyl-1,4-dihydro-3-quinolinecarboxylate (5b), while such photoaddition of the solvent did not proceed in ethanol and 2-propanol but instead ethyl 1,4-dihydro-3-quinolinecarboxylate (6) and dimeric compounds were formed, both of which were unstable and finally reverted to 2 at room temperature in air. In the case of ethyl 2-quinolinecarboxylate two types of the products, ethyl 4-hydroxyalkyl-1,4-dihydro-2-quinolinecarboxylate (7) and ethyl 1,4-dihydro-2-quinolinecarboxylate (8) were obtained in ethanol and 2-propanol but the yields of those products were poor. On the basis of triplet quenching experiments, the photochemical reactions of those ethyl quinolinecarboxylates are suggested to occur through hydrogen abstraction from the solvents by the ring nitrogen in the S1 state.
Studies on Hydrogenation by Nickel Complexes. 5. The Selective Hydrogenation of 1,4-Cyclohexadienes to Cyclohexenes Catalyzed by a Nickel Complex
Authors: Sakai Mutsuji , Hirano Nobuo , Harada Fumiya , Sakakibara Yasumasa , Uchino Norito
Published: July 2006

1,4-Cyclohexadiene was hydrogenated selectively to cyclohexene with a nickel catalyst generated from bis(acetylacetonato)nickel(II), triethyldialuminium trichloride, and triphenylphosphine at 40 °C under an atmospheric pressure of hydrogen. The hydrogenation of eleven kinds of alkyl-substituted 1,4-cyclohexadienes gave the corresponding cyclohexenes in good yields by the nickel catalyst. The structural factors of the alkyl substituent on the diolefin are shown to affect the hydrogenation rate. The homogeneous nickel catalyst system, in which a nickel hydride complex NiH(PPh3)(AlCl4) is supposed to be an active species, was effective for the selective hydrogenation of the diolefin to the olefin. A plausible pathway involving π-allylnickel complexes for the hydrogenation is proposed.
Unequivalent Chemical Environment of Diene Groups in 1- and 2-Acyl Chains of Polymerizable Lipids Analyzed by Radical Polymerization
Authors: Ohno Hiroyuki , Takeoka Shinji , Tsuchida Eishun
Published: July 2006

1,2-Di-O-(2,4-octadecadienoyl)-sn-glycero-3-phosphorylcholine is polymerized by radical initiators. An azobisisobutyronitrile (AIBN) and an azobis(2-amidinopropane) dihydrochloride (AAPD) are incorporated into hydrophobic membrane region of the lipid liposomes and an aqueous medium, respectively by sonication. The use of either AIBN or AAPD gives polymerization conversion of about 50% at 60 °C. This is not improved by the elongation of polymerization period at 60 °C or the increase of the amount of these radical initiators. The lyophilized lipids thus polymerized by either AIBN or AAPD are soluble in methanol suggesting the formation of linear polymers. Simultaneous polymerization by both AIBN and AAPD provides almost complete polymerization. AIBN and AAPD have been suggested to initiate radical polymerization of diene groups in 1- and 2-acyl chains, respectively. Potassium peroxodisulfate, another water-soluble radical initiator, yields polymerized liposomes with polymerization conversion of more than 80%. This corresponds to the polymerization of diene groups of not only 2- but also 1-acyl chains due to the hydroxyl radicals which are generated by the radial transfer in an aqueous medium. These different initiation reactions are attributed mainly to the unequivalent chemical environment of diene groups in 1- and 2-acyl chains.
Nucleotide Sequences of DNA and Their Structural Analysis. Categorical Discrimination of 5′-Splice Site Sequences in mRNA Precursors
Authors: Iida Yôichi
Published: July 2006

The signals which direct excision of introns from mRNA precursors in higher eukaryotes’ genes are not well-understood. Although a consensus sequence, (Remark: Graphics omitted.), has been proposed with the 5′-splice site, actual 5′-splice site sequences differ from it to a greater or lesser degree. In the present paper, structural analysis of 5′-splice site sequences was done by using quantification theory (class II). Nucleotide sequences were transformed into categorical data, and categorical discriminant analysis was carried out between 5′-splice site sequences and sequences other than 5′-splice site. Relative importance of each position of nucleotide sequence was then estimated by calculating partial correlation coefficient on each position.
Interaction of Divalent Metal Acids with Pentyl Alcohol and Isopentyl Acetate
Authors: Beg Mirza Aijaz , Kidwai Mohd Shakil
Published: July 2006

Extraction of monobasic divalent metal bromo acids in pentyl alcohol–benzene and isopentyl acetate–benzene mixtures was studied at room temperature (25 °C). Three molecules of pentyl alcohol ae well as of isopentyl acetate were associated with each metal acid molecule of cobalt and copper in the organic phase. Zinc, cadmium, and mercury acids take up two molecules of pentyl alcohol and one molecule of isopentyl acetate. Metal acids studied here mostly exist as monomer in the organic phase. In pentyl alcohol, however, copper acid is monomeric only at lower concentrations (4×10−5 to 2×10−4M) and dimeric at higher concentrations (3.3×10−4 to 1.4×10−3M).
Coordination Chemistry of New Sulfur-Containing Ligands: Transition Metal Complexes of N-Ethoxycarbonyl-1-pyrrolecarbothioamide
Authors: Chauhan Veena , Dikshit Sheo Kant
Published: July 2006

Reaction of N-ethoxycarbonyl-1-pyrrolecarbothioamide (Hept) with a variety of transition metal ions leads to the formation of [MnII(ept)2] (M=Ni, Cu, Pd, Pt), [MII(ept)2(py)] (M=Co, Ni), [RhICl(Hept)PPh3)]2, and [MIIICl(ept)2(H2O)] (M=Ru, Rh). Reaction of Hept with Ag(I), Cu(II), Pb(II), Hg(II), and Cd(II) under refluxing conditions yields the corresponding sulfides and an oxygenated form of the ligand (Hept), which was characterized as (Remark: Graphics omitted.). All metal complexes have been characterized on the basis of analytical, IR and electronic spectral, and magnetic measurement studies.
α,β-Epoxy Sulfoxides as Useful Intermediates in Organic Synthesis. IX. A Novel Synthesis of Alkyl Vinyl Ketones and Divinyl Ketones from Carbonyl Compounds and 1-Chloro-3-phenylthiopropyl Phenyl Sulfoxide as a Three-Carbon Homologating Agent
Authors: Satoh Tsuyoshi , Kumagawa Takumi , Sugimoto Atsushi , Yamakawa Koji
Published: July 2006

The α,β-epoxy sulfoxides easily derived from carbonyl compounds and 1-chloro-3-phenylthiopropyl phenyl sulfoxide were treated with sodium benzeneselenolate to give β-phenylthio carbonyl compounds in excellent yields. The phenylthio group was oxidized to the sulfinyl group and was then treated with a base to afford alkyl vinyl ketones in quite good yields. This reaction presents a novel method for the preparation of alkyl vinyl ketones from carbonyl compounds by three-carbon homologation. The treatment of α,β-epoxy sulfoxides mentioned above with benzenethiolate gave α,β′-bis(phenylthio) ketones. The elimination of the both thio groups afforded divinyl ketones.
Protein Engineering of Dihydrofolate Reductase. pH Dependency of Phe-31 Mutants
Authors: Taira Kazunari , Chen Jin-Tann , Fierke Carol A , Benkovic Stephen J
Published: July 2006

Site-specific mutations on dihydrofolate reductase from Escherichia coli at the Phe-31 site have generated (Try-31)-DHFR and (Val-31)-DHFR mutant enzymes. The pH dependence of logV and logV⁄KDHF for these enzymes suggests that protonation is important for both the interaction of dihydrofolate and the maximum velocity of the reaction. More importantly, a “hollow” is observed for the Tyr-31 mutant in a logV⁄K–pH profile, necessitating a modification of the wild-type kinetic scheme. The intrinsic pKa of 5.8, obtained based on the modified more general kinetic scheme, for the Tyr-31 mutant agrees well with that obtained from inhibition studies by 2,4-diamino-6,7-dimethylpteridine.
Electrooxidative Functionalizations of Dehydroabietic Acid
Authors: Uneyama Kenji , Katayama Tatsuo , Torii Sigeru
Published: July 2006

Dehydroabietic acid methyl ester (1) was converted into 7-acetoxydehydroabietic acid methyl ester by direct electrooxidation in acetic acid and 7-oxodehydroabietic acid methyl ester by ruthenium dioxide-mediated oxidation. Non-Kolbe type electrodecarboxylation of 1 resulted in the introduction of a double bond into the ring A of 1.
Synthesis and Characterization of Imidazolate-Bridged Trinuclear (Copper(II)–Manganese(II)–Copper(II)) Complexes
Authors: Matsumoto Naohide , Kanesaka Junko , Ohyoshi Akira , Nakamura Masaaki , Kohata Susumu , Okawa Hisashi
Published: July 2006

Imidazolate-bridged trinuclear(copper(II)–manganese(II)–copper(II)) complexes [CuLMn(tfa)2LCu]2H2O 1 and [CuLMn(hfa)2LCu]3H2O 2 have been prepared and characterized, where tfa=trifluoroacetylacetonate, hfa=hexafluoroacetylacetonate, H2L=unsymmetrical quadridentate Schiff base derived from the condensation reaction of acetylacetone, ethylenediamine, and 4-formylimi dazole with the mole ratio of 1:1:1. The magnetic susceptibility data were represented by a spin-only interaction model(1/2–5/2–1/2) with JMn-Cu value of −13 cm−1 for 1 and −8 cm−1 for 2.
Enantiotropy of 2,4-Diamino-6-[2-(2-methyl-1-imidazolyl)ethyl]-1,3,5-triazine
Authors: Kamagata Kazuo , Yoshida Shuuji
Published: July 2006

Measurements using elementary analysis, differential thermal analysis, IR spectroscopy, and X-ray diffractometry have revealed that the title triazine assumes two crystalline forms α and β. The conversion from α to β proceeds rapidly at 230 °C, whereas the reversal takes place slowly at 60 °C and 95% RH.
Nonacarbonyldiiron-Induced Reaction of 3-Azido-1,2,3-triphenylcyclopropene and 4,5,6-Triphenyl-1,2,3-triazine
Authors: Kobayashi Tomoshige , Murata Naoki , Nitta Makoto
Published: July 2006

The [Fe2(CO)9]-induced reaction of 3-azido-1,2,3-triphenylcyclopropene (1) undergoes elimination of a nitrogen molecule and C–C bond cleavage to result in the formation of benzonitrile, diphenylacetylene, 2,3-diphenylinden-1-one, and 1,2,3-triphenylpropen-1-one. The similar reaction of 4,5,6-triphenyl-1,2,3-triazine, which is an isomer of 1, undergoes reductive N–N bond cleavage to give 3,4,5-triphenylpyrazole in good yield.
Ion Selectivity of 14-Crown-4 Derivative Possessing Two Potential Anionic Sites on Extraction of Alkali and Alkaline-Earth Metal Ions
Authors: Kimura Keiichi , Tanaka Mutsuo , Shono Toshiyuki
Published: July 2006

A lipophilic 14-crown-4 derivative bearing two dinitrophenol moieties was synthesized and its ion selectivity was elucidated on cation extraction from a basic aqueous phase into an organic phase. The crown ether derivative was found to possess preferences for Ca2+ and Sr2+ as well as Li+.
Syntheses and Biological Activities of Neurokinin A Analogs Substituted with Glycine
Authors: Hashimoto Tadashi , Kurosawa Katsuro , Uchida Yoshiki
Published: July 2006

Five neurokinin A (NKA) analogs substituted with glycine at position 3, 4, 5, 6, or 7 were synthesized by Merrifield’s solid phase method. The contractile activities of the synthetic analogs were assayed on isolated guinea pig ileum and rat vas deferens. The results suggest that Asp4, Phe6, and Val7 residues of NKA may be essential for the intrinsic activity on guinea pig ileum and on rat vas deferens, respectively.
Bleaching of Bis[1-(4-dimethylaminophenyl)-2-phenylethanedithione]nickel(0) in Polymer Solution and Polymer Matrix
Authors: Enmanji Koe
Published: July 2006

Bis[1-(4-dimethylaminophenyl)-2-phenylethanedithione]nickel(0) (BDN), a Q-switch dye for neodymium lasers, bleached in polymer matrix such as poly(butyl methacrylate). To elucidate the bleaching mechanism, the effect of water-soluble polymer added to dimethyl sulfoxide (DMSO) solution of BDN on the bleaching rate was investigated. BDN was reduced by a water-soluble polymer such as poly(vinyl alcohol) (PVA), starch, and cyclodextrin (CD) in DMSO. BDN bleached in DMSO solution with PVA and bleaching rate depended on the saponification number of PVA. BDN was also bleached by adding CD to DMSO solution. From the concentration dependence of CD on BDN bleaching rate, it was presumed that the vicinity of Ni of BDN is not included in β- and γ-CD, but is included in α-CD. For avoiding reduction of BDN by CD, 2,4,5-tri-O-methoxy-β-cyclodextrin (T-β-CD) was examined. BDN was not reduced by an inclusion complex of BDN with T-β-CD. The storage life of Q-switch with matrices of poly(butyl methacrylate) and polystyrene was determined. The Q-switch with polystyrene matrix having transmittance of 70.0% is expected to have transmittance of 70.4% after strage for 10 years at 25 °C.
Metal Colloids Produced by Means of Gas Evaporation Technique. IV. Size Distribution of Small Mg and In Particles
Authors: Kimura Keisaku
Published: July 2006

Ultrafine metal particles with different sizes have been obtained by several preparation methods. The smallest Mg particles (the average diameter Dm of about 2 nm) were obtained by the matrix isolation method in He and the largest (Dm, 100 nm) by the conventional gas evaporation method in Ar. By changing the pressure and the kind of gas, particles with an intermediate diameter have been obtained. The size distribution of small In particles was discussed.
Silicon-29 NMR Chemical Shifts of Organosilicons as Studied by the FPT CNDO/2 Method
Authors: Takayama Toshio , Ando Isao
Published: July 2006

The 29Si chemical shifts of silicon hydrides and fluorosilanes were calculated by means of the FPT method within the CNDO/2 framework. It was found that, by a small revision of the formula for the off-diagonal elements of the core Hamiltonian matrix in the CNDO/2 method, the calculated results agree well with the gross trend of the experimental values of the 29Si chemical shifts in the literature. Further, the relationship between the 29Si chemical shift and the electronic structure was discussed.
A New Type of Tetradentate Square-Planar N2O2 Ligands. Copper(II) Complexes of 6,6′-Bis(acylamino)-2,2′-bipyridines
Authors: Yamada Masaki , Araki Koji , Shiraishi Shinsaku
Published: July 2006

A new type of N2O2 tetradentate ligands, 6,6′-bis(acylamino)-2,2′-bipyridines, was synthesized and their complex formations with copper(II) were investigated. They form two types of 1:1 complexes; one is the non-deprotonated type having external counter anions and the other is the deprotonated type having no external counter anions. They serve as square planar N2O2 tetradentate ligands in either case and the structures of the complexes are very similar to salen complexes. The structures and properties of these complexes were investigated and discussed.
Synthesis, and Crystal and Molecular Structure of Bis[2-(2-benzoxazolyl)phenolato]nitratoiron(III), Fe(C13H8O2N)2(NO3)
Authors: Furuhashi Akiko , Inayoshi Tomoko , Ouchi Akira
Published: July 2006

The title complex was newly synthesized and its crystal and molecular structure was determined by the single-crystal X-ray diffraction technique. The crystal is monoclinic, space group C2⁄c, a=16.005(4), b=10.520(2), c=15.338(4) Å, β=114.68(2)°, and Z=4. In the complex, the central metal atom is hexa-coordinated being in a deformed octahedral geometry: Two 2-(2-benzoxazolyl)phenolato ligands form six-membered chelate rings being coordinated with their oxazolyl nitrogen and phenolato oxygen atoms, while the nitrate ion acts as a bidentate with its two oxygen atoms. As the benzoxazolyl ring is parallel and overlapped with that of the neighboring complex along the c-axis, where the interplane distance is 3.557 Å, some interaction between the rings is expected. As this complex in solid state is deep violet, almost black, in color, some charge-transfer bands are expected to exist in its electronic spectra. The bis[2-(2-benzothiazolyl)phenolato]nitratoiron(III) was found to be isomorphous to the title complex.
Synthesis and Chromogenic Properties of Some Phthalazinylhydrazones and Extractive Spectrophotometric and Analogue-Derivative Speotrophotometric Determination of Trace Amounts of Nickel with Di-2-pyridylmethanone 1-Phthalazinylhydrazone
Authors: Odashima Tsugikatsu , Yamada Minoru , Yonemori Naoki , Ishii Hajime
Published: July 2006

Four kinds of 1-phthalazinylhydrazones have been synthesized and their chromogenic properties and reactivities with metal ions investigated. Of the synthesized hydrazones, di-2-pyridylmethanone 1-phthalazinylhydrazone (DPPhH) proved to be the best chromogenic reagent for nickel. It reacts with nickel(II) at pH above 2.5 to form a 1:2 (nickel–ligand) complex extractable into various organic solvents. The extracted species into benzene has an absorption maximum at 500 nm and gives a maximum and constant absorbance in the pH range 4.3–10.7. Beer’s law is obeyed over the range 0.1–1.0 μg cm−3 of nickel. The molar absorptivity (ε) and the sensitivity for an absorbance of 0.001 are 5.4×104 dm3 mol−1 cm−1 and 1.08 ng cm−2 at 500 nm, respectively. A sensitive and selective extraction-spectrophotometric method for the determination of nickel at μg cm−3 levels is proposed and has been applied successfully to the analysis of iron and steel samples. The proposed method can be made more sensitive by the introduction of an analogue-derivative spectrophotometric technique.
Chemical Behavior of an Oxygen Ligand in the Reaction between Oxo Complex of RuIV and Alcohols to Give Both Hydroxo and Alkoxo Complexes of RuIII
Authors: Nagao Hirotaka , Aoyagi Kimitake , Yukawa Yasuhiko , Howell F Scott , Mukaida Masao , Kakihana Hidetake
Published: July 2006

Under mild conditions, trans-[RuCl(O)(py)4]+ in alcohols changes to an alkoxo complex, trans-[RuCl(OR)(py)4]+, The hydroxo complex, trans-[RuCl(OH)(py)4]+, which retains the reactive oxygen of the oxo complex, was found to exist as a precursor in the formation of the alkoxo complex. The reaction progress was traced by spectrometrical and 18O-labelling experiments.
Silicon Polonovski Reaction. Formation and Synthetic Application of α-Siloxy Amines
Authors: Tokitoh Norihiro , Okazaki Renji
Published: July 2006

A new and versatile synthetic intermediate, α-siloxy amine was prepared in situ by the base-promoted rearrangement of a siloxyammonium salt obtained by treatment of a tertiary amine N-oxide with trialkylsilyl trifluoromethanesulfonate. The best combination of the base and silylating reagent was found to be methyllithium and t-butyldimethylsilyl trifluoromethanesulfonate. The reactions of α-siloxy amines with acyl halides and haloformates gave the corresponding amides and carbamates in moderate to good yields, respectively. Treatment of α-siloxy amines with acetic acid resulted in a direct dealkylation to free secondary amines. Fluoride induced alkylation of α-siloxy amines using alkyl halides as electrophiles leading to tertiary amines was also examined and demonstrated to be a new transalkylation method of amines.
Reactions of Trialkylstannane Anions R3Sn− with Arylstannanes ArSnR3′
Authors: Mochida Kunio
Published: July 2006

The reactions of trialkylstannane anions R3Sn− with arylstannanes ArSnR3′ have been investigated; trialkylstannane anions with arylstannanes at 50 °C gave substitution products ArSnR3 in good yields. Most of these substitution products are diverted to reduction products ArH when t-butylamine for trapping free anionoids is present in the reaction mixture. These results are consistent with an initial tin–alkali metal exchange or an electron-transfer forming aryl anions and distannanes which subsequently react to the substitution products. Aryl radical intermediates by an electron-transfer process are also important in the reactions of trialkylstannane anions with electron-withdrawing groups-substituted arylstannanes, 1-naphthylstannanes, diphenylstannanes, and triphenylmethylstannane as good electron acceptor substrates.
Electrochemical Synthesis of Poly(amino acid)s, Poly(amino acid)–Urethane Copolymers, and Electroconductive Poly(amino acid)–Polypyrrole Complex Films
Authors: Komori Tetsuo , Nonaka Tsutomu , Fuchigami Toshio , Zhang Kunmao
Published: July 2006

When amino acid N-carboxy anhydrides (NCA’s) were polymerized with various electrogenerated base (EGB) catalysts, the yield of poly(amino acid)s remarkably increased and the reaction time was extremely shortened compared with the conventional method using triethylamine catalyst. This novel polymerization method was successfully applied to the copolymerization of different kinds of NCA’s and to the preparation of poly(amino acid)–urethane copolymers. NCA’s were also polymerized with the EGB’s in the matrix of polypyrrole simultaneously formed by the anodic polymerization of pyrrole to provide electroconductive poly(amino acid)–polypyrrole complex films which were stable in the air and flexible.
Decay Reactions of Aryldiazenyl Radicals in Solution
Authors: Suehiro Tadashi , Masuda Seiichi , Nakausa Ryuichi , Taguchi Masamichi , Mori Atsushi , Koike Akemi , Date Munehiro
Published: July 2006

The decay processes of aryldiazenyl radicals were studied by using a time-resolved ESR method. The first order rate constants of decomposition were determined at −117–−48 °C in cyclopropane solutions in the presence or absence of olefins. Aryldiazenyl radicals were relatively persistent and the k1 of phenyldiazenyl-d5 at −96 °C in cyclopropane was 34 s−1. The k1 of 20 aryldiazenyl radicals at −96 °C afforded a ρ value of +1.53 (r=0.91) in a Hammett plot. Activation energies ranged from 46.2 to 25.2 kJ mol−1 and the frequency factors, log A, from 13.2 to 8.2 s−1. The second-order decay rates were measured at the initial period of the decay process at lower temperatures, in a batch system (cyclopropane) and in a flow system (isohexane). The rate constant of phenyldiazenyl-d5 in cyclopropane was 9.2·10−5 M−1 s−1 at −93 °C and the Arrhenius parameters were Ea=23.5 kJ mol−1 and logA=12.77 M−1 s−1, respectively.
Photochemical Reactions of Contact Charge-Transfer Pairs of 1-Arylcyclohexenes and Oxygen
Authors: Kojima Masanobu , Sakuragi Hirochika , Tokumaru Katsumi
Published: July 2006

Photoexcitation of contact charge-transfer (CCT) pairs of 1-arylcyclohexenes 1 (aryl: phenyl, 4-methylphenyl, and 4-methoxyphenyl) and oxygen in acetonitrile and benzene gave 1,2-epoxy-1-arylcyclohexanes 2 as major products together with 2-aryl-2-cyclohexen-1-ols and acetophenones 4. Similar irradiation of the CCT pairs in methanol/acetonitrile afforded mainly 2-aryl-2-methoxycyclohexanols instead of 2 and small amounts of 1-aryl-1-methoxycyclohexanes, 2-aryl-2-cyclohexen-1-ones, and 4. The formation of these products can be explained by photoinduced electron transfer in the excited CCT pairs generating radical cations of 1 and superoxide anions.
Optically Active Polyamides Having (−)-Anti Head-to-Head Coumarin Dimer Component. 3. Chiral Recognition Ability
Authors: Chen Yun , Saigo Kazuhiko , Yonezawa Noriyuki , Tachibana Kouzou , Hasegawa Masaki
Published: July 2006

Optically active polyamides (3a–f) and O-methylated polyamides (5a,d,e), derived from (−)-anti head-to-head coumarin dimer [(−)-1], were absorbed on macroporous silica gel particles and used as chiral stationary phases for direct resolution of racemates (6–13) having aromatic moiety by high-performance liquid chromatography. Polyamide 3a and 3e could resolve 6–10 and 9–13, respectively (separation factor α>1.03), and 3d showed especially high selective recognition ability to 7 (α=1.63). However, 3c,f and 5a showed no resolution ability to all of the racemates. The high recognition ability of 3a is attributed mainly to the difference in stability between the diastereomeric complexes formed by the simultaneous interaction of 3a with the racemates. The recognition ability of polyamides derived from piperazine (3d, 5d) and 1,4-phenyl-enediamine (3e, 5e) seems to be attributed not only to the simultaneous interaction but also to their ordered conformations in the film state.
The Interaction of Pigment with Polystyrene Latex Particles Prepared Using an Amino-Acid-Type Amphoteric Emulsifier
Authors: Kato Kazufumi , Kanda Kouichiro , Kondo Harumi , Esumi Kunio , Meguro Kenjiro
Published: July 2006

An emulsion polymerization of styrene in the presence of an amino-acid type amphoteric emulsifier (Nε-lauroyl-Nα,Nα-dimethyllysine (DMLL)) was carried out at pH 7.0. The stability of mixed dispersions containing the latex particles prepared with DMLL and titanium dioxide (TiO2) was then discussed as a function of the pH in a mixed dispersed solution. The zeta-potential of the synthesized latex particles was significantly dependent on the pH and showed the existence of an isoelectric point (IEP) at pH 4.5. On the other hand, TiO2 particles had their IEP at pH 8.5. Below pH 4.5 and above pH 8.5, the mixed dispersions of the synthesized latex particles and TiO2 particles were well-dispersed because of their electric repulsion. In the range of pH 4.5–8.5, where the latices were negatively charged, while the TiO2 were positively charged, at low concentrations of the latex particles the mixed suspension was dispersed, but with an increase in the number of latex they heterocoagulated and were then redispersed at high concentrations of the latex particles. The mechanisms of these processes are discussed.
Kinetics of Oxidation of Amino Acids by Chloramine-T. A Reinvestigation on the Oxidation of Alanine, 2-Aminobutyric Acid, Valine, Serine, and Threonine
Authors: Ramachandran M Shanmugam , Vivekanandam T Subburamiyer
Published: July 2006

The kinetics of oxidation of amino acids in aqueous medium were reinvestigated. The rate of oxidation follows second order with respect to chloramine-T (CAT) and an inverse dependence on [p-toluene-sulfonamide] (RNH2). At constant [RNH2] the rate of the reaction can be represented as (in the absence of chloride ion)

\frac−d[CAT]dt=ka[CAT]2+kb\frac[Amino Acid][CAT]2[H+]+kc\frac[Amino Acid]2[CAT]2[H+]2.

A linear relationship exists between pK1 and the rate constants. This shows the electrophilic attack of the oxidant at the carboxylato group of the amino acid. The effect of chloride ion on kobsd is catalytic. The mechanisms of the reactions are discussed in terms of the kinetic results.
t-BuCl–Nal as a Reagent for the Selective Reduction of Olefinic Double Bond of β-Phenyl α,β-Unsaturated Carbonyl Compounds
Authors: Sakai Takashi , Miyata Kazuyoshi , Hondo Kazuomi , Utaka Masanori , Takeda Akira
Published: July 2006

β-Phenyl α,β-unsaturated carbonyl compounds were conveniently reduced to the corresponding saturated aromatic compounds by heating with t-BuCl–Nal in acetonitrile.
Selective 1,2-Reduction of α,β-Unsaturated Carbonyl Compounds with LnCpCl2(THF)3/NaBH4
Authors: Komiya Sanshiro , Tsutsumi Osamu
Published: July 2006

Highly selective 1,2-reduction of conjugated α,β-unsaturated carbonyl compounds such as enones and unsaturated aldehydes has been achieved by NaBH4/LnCpCl2(THF)3 (Ln=Sm and Er) in MeOH under ambient conditions.
Tin-Promoted Electrochemical Hydrodimerization of Ionones
Authors: Uneyama Kenji , Tokunaga Takumi , Torii Sigeru
Published: July 2006

Electrochemical hydrodimerization of α and β-ionones in the presence of metal tin provides the corresponding hydrodimers in 77 and 60% yields, respectively.
The Reaction of Calcium Atoms with Group 4B Catenates, Me3E–E′Me2R (E, E′=Si, Ge, Sn; R=Me, Cl)
Authors: Mochida Kunio , Yamanishi Takayuki
Published: July 2006

Calcium atoms are thought to be inserted into E–E′ bonds of group 4B catenates, Me3E–E′Me2R (E, E′=Si, Ge, Sn; R=Me, Cl) to give the corresponding Me3E–Ca–E′Me2R compounds.
Preparation of Arylsulfonyl-Substituted 3,8-Diphenyl-1,2-diazacycloocta-2,4,6,8-tetraenes and Their Thermolysis
Authors: Yogi Seiichi , Hokama Kozo , Tsuge Otohiko
Published: July 2006

Nucleophilic substitution of 4,7-dichloro-3,8-diphenyl-1,2-diazocine with benzenesulfinate gave stable 7-chloro-4-phenylsulfonyl- and 4,7-bis(phenylsulfonyl)-1,2-diazocine. The 4-mono(arylsulfonyl)- and 4,7-bis(arylsulfonyl)-1,2-diazocines were obtained by oxidation of the corresponding mono(arylthio)- and bis(arylthio)-1,2-diazocines, respectively. 4-Phenylsulfonyl-7-phenylthio-1,2-diazocine was also prepared. Thermolysis of all the diazocines gave only pyridine derivatives, and the feature of the thermolysis was also described.
Titanium Oxide-Supported Carbonylmolybdenum Catalyst in Liquid Phase: Application to Allylic Alkylation of Methyl p-Tolylsulfonylacetate
Authors: Masuyama Yoshiro , Mitsunaga Yutaka , Kurusu Yasuhiko , Segawa Koh-ichi
Published: July 2006

Titanium oxide-supported carbonylmolybdenum catalyst was applied to selective monoallylation of methyl p-tolylsulfonylacetate using allylic acetates or carbonates in refluxing dioxane. This reaction required both 2,2′-bipyridyl as a ligand and sodium hydride as a base for preparation of the salt of methyl p-tolylsulfonylacetate.
Infrared Study of Structural and Compositional Changes in Orthorhombic Hydrogen Molybdenum Bronze, H0.3MoO3, by Heating in Vacuo
Authors: Ohno Takashi , Miyata Hisashi , Hatayama Fumikazu , Sotani Noriyuki
Published: July 2006

Hydrogen molybdenum bronze, H0.3MoO3, heated in vacuo was studied by FT-IR spectroscopy. The spectrum near 1000 cm−1 analyzed by a microcomputer system was confirmed to be composed of three bands. Among them, bands at 1005 and 990 cm−1 correspond to the Mo=O bonds of orthorhombic bronze and rhombic MoO3, respectively.
The Crystal and Molecular Structures of the Scandium(III) and Yttrium(III) Chloroacetates, [Sc(ClCH2CO2)3]n and [Y3(ClCH2CO2)9(H2O)4]n·nH2O
Authors: Sugita Yoshihiko , Ohki Yoshiyuki , Suzuki Yasuo , Ouchi Akira
Published: July 2006

The crystal and molecular structures of the titled scandium(III) (1) and yttrium(III) chloroacetates (2) were determined by the single-crystal X-ray diffraction method. 1 is monoclinic, with the space group P21/n, a=12.148(4), b=8.860(5), c=11.028(4) Å, and β=103.31(3)°. In 1, the metal atom has the hexa-coordinated octahedral geometry, and any pair of the neighboring metal atoms are bridged by three bidentate carboxylate ions, forming an infinite chain. 2 is isomorphous with the heavy lanthanoid salts, [Ln3(ClCH2CO2)9(H2O)4]n·nH2O (Ln=Gd–Yb), and its crystal structure closely resembles that of the erbium(III) complex.
The Novel Syntheses of Photoreversible Cyclobutanocrown Ethers by the Intramolecular Photoaddition of α,ω-Dicinnamoyl Polyethylene Glycol Derivatives
Authors: Akabori Sadatoshi , Habata Yoichi , Nakazawa Misako , Yamada Yoko , Shindo Yoichi , Sugimura Tokuko , Sato Sadao
Published: July 2006

Irradiation of a solution of dicinnamates of o-bis(3-hydroxy-1-oxapropyl)benzene and o-bis(6-hydroxy-1,4-dioxahexyl)benzene in methanol by Pyrex-filtered UV light gave the corresponding intramolecular pseudophotodimerized crown ethers, and irradiation of the crown ethers in methanol by 220 nm UV light gave the open chain starting dicinnamates in reverse. The structures of the isolated crown ethers were confirmed to be δ-form by the 1H NMR spectra and X-ray analysis.
X-Ray Crystal Structure of 7,16,24,33-Tetrathia[3]paracyclo[3](1,3)ferroceno[3]paracyclo[3](1,3)ferrocenophane
Authors: Hisatome Masao , Yoshihashi Masamichi , Yamakawa Koji , Iitaka Yoichi
Published: July 2006

The crystal structure of the title compound, a macrocyclic thioether containing two 1,3-ferrocene and two 1,4-benzene moieties, has been determined by X-ray diffraction. The compound is in a chair-like conformation in the crystal and solvated with one molecule of benzene which was used for crystallization.
Studies of Collectors. IX. The Flotation of a Trace Amount of Uranium by Using 2-(Alkylamino)propionohydroxamic Acid and Cotelomer-Type Surfactants Bearing Hydroxyaminocarbonyl and Pyridyl Groups
Authors: Koide Yoshifumi , Uchino Masazumi , Yamada Kimiho
Published: July 2006

Chelating surfactants bearing hydroxyaminocarbonyl and amino groups (RnAHx) and cotelomer-type surfactants bearing hydroxyaminocarbonyl and pyridyl groups (Ls–VP–Q–Hx) were prepared and applied as flotation collectors for a trace amount of uranium. The uranium in an aqueous solution of pH 4–8 and in seawater was floated more effectively by ion flotation using RnAHx or by foam fractionation using Ls–VP–Q–Hx, compared with alkylhydroxamic acid (RnHx) and telomers bearing hydroxyaminocarbonyl groups (Lo–Hx). The effective flotation was concluded to be due to the chelate effects between the two groups on the complex formation and to the HLB of the resulting complex. Furthermore, the uranium recoveries were examined by using a hydroxamic acid polymer (62Hx), a N-methylhydroxamic acid telomer (Ls5.6MHx), and its cotelomer (Ls3.2VP4.5MHx).
An Ab Initio Molecular Orbital Study on Infrared Absorption Spectrum of ν1 Vibration in Chloroform Vapor
Authors: Hayano Tomoaki , Takeuchi Hisao , Miyazaki Tomoo
Published: July 2006

The infrared absorption frequency and intensity of the ν1 vibration, referring to the C–H stretching of chloroform vapor, have been calculated from the theoretical potential energy and dipole-moment functions determined by an ab initio molecular orbital calculation. The selection effect of a Gaussian basis set in the ab initio MO method on the calculated frequency and intensity has been studied. It has been pointed out that the theoretical dipole-moment function is sensitive to a slight displacement of the chlorine in the ν1 vibrational mode.
Fluorescence Quenching of N-Phenyl-1-naphthylamine by Nitriles, Esters, and Amines
Authors: Hamai Sanyo
Published: July 2006

The equilibrium constants for the hydrogen bonding between N-phenyl-1-naphthylamine (NPNA) and proton acceptors (1,4-dioxane, nitriles, esters, and amines) in cyclohexane and the corresponding thermodynamic parameters have been determined. The fluorescence of NPNA is quenched by nitriles, esters, and amines. In the cases of nitriles and esters, the quenching is caused by compounds in which a cyano or carboxyl group is conjugated with a double bond. The rate constants for quenching of the NPNA fluorescence by methyl tiglate, methyl 3,4,5-trimethoxybenzoate, and 2,4,6-trimethylpyridine are 81, 73, and 69% of those by methyl acrylate, methyl benzoate, and pyridine, respectively. These findings can be interpreted in terms of the charge-transfer interaction through the hydrogen bond between NPNA (an electron donor) and the proton acceptors (electron acceptors) except for the amines, for which a mechanism different from the charge-transfer mechanism may be important in explaining the fluorescence quenching.
Unimolecular Decomposition of Silane in Shock Waves
Authors: Tanaka Hitoshi , Koshi Mitsuo , Matsui Hiroyuki
Published: July 2006

Thermal decomposition of silane highly diluted in argon was studied behind incident shock waves at the temperatures ranging from 1250 to 1600 K. The decomposition course was followed by monitoring the infrared emission of silane at 4.4 μm. It was confirmed that the effects of consecutive reactions on the decay rate of silane were negligible under our experimental conditions. The unimolecular rate constants obtained directly from the decay curve of silane were found to be smaller than previous experimental values but consistent with the result of the recent trajectory-RRK calculation. It was also found that the addition of molecular hydrogen or nitrogen monoxide to the reactant mixtures had no effect on the decomposition rate of silane.
Formation of Molecular Complexes of Water-Soluble Porphyrin with Cation–18-Crown-6 Complexes
Authors: Tabata Masaaki , Yamada Isao
Published: July 2006

The formation of molecular complexes of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphine (H2tspp) with cation–18-crown-6 (M(18C6)) has been studied spectrophotometrically at I=0.1 mol dm−3 (MX and MX2, M: Na+, K+, Cs+, NH4+, Ca2+, Sr2+, Ba2+, X: NO3−, Cl−, Br−, I−, SCN−), and pH 7.0 (N,N′-bis(2-sulfonatoethyl)piperazine: PIPES buffer, 2.0×10−3 mol dm−3). The absorption spectrum of H2tspp considerably changed in the presence of both cation and 18-crown-6, but not in the absence of either of them. The formation constants (logK) of the molecular complexes (M(18C6)·H2tspp) were found to be 2.17±0.05, 2.31±0.03, 2.45±0.03, 2.58±0.02, 1.94±0.03, 2.07±0.02, and 2.12±0.02 for Na+, K+, Cs+, NH4+, Ca2+, Sr2+, and Ba2+, respectively at 25.0±0.5 °C and I=0 mol dm−3. Thermodynamic parameters ΔH/(kJ mol−1) and ΔS/(J K−1 mol−1) are −19.9, −25.0; −33.0, −66.0; −29.3, −50.8; −48.5, −113.7; −21.9, −34.2 and −32.5, −68.0 for Na+, K+, Cs+, NH4+, Sr2+, and Ba2+. The enthalpy changes are linearly correlated to the entropy changes. The equilibrium studies show that charge transfer between M(18C6) and porphyrin π-system is a driving force for the formation of the molecular complex (M(18C6)·H2tspp) as well as hydrophobic interaction.
Nonsteroidal Antiinflammatory Drugs. VI. The Crystal and Molecular Structure of (±)-(2S*)-2-[4-((1S*)-2-Oxocyclopentylmethyl)phenyl]propionic Acid and Force-Field Calculations
Authors: Hata Tadashi , Ohashi Yuji , Sasada Yoshio
Published: July 2006

The crystal structure of the title compound was determined by X-ray diffraction techniques. The final R index was found to be 0.072 for 1187 reflections. The torsional angles of the 2-phenylpropionic acid moiety were comparable to those in other antiinflammatory arylpropionic acids. Force-field energy calculations suggested that the α-methyl substituent to the carboxyl group restricts the rotation of the benzene ring about the Cα-phenyl bond. This restricted conformation may be related to the antiinflammatory activity.
Cobalt(III) Complexes of Salen Analog with Thioether Pendant Group. X-Ray Structure Analysis and Thioether Coordination Effects
Authors: Horiuchi Kaoru , Mikuriya Masahiro , Okawa Hisashi , Kida Sigeo
Published: July 2006

A pentadentate salen analog with a pendant thioether group, N,N′-disalicylidene-2-methyl-4-ethylthio-1,2-butanediamine (H2L), formed two types of cobalt(III) complexes, [Co(L)]ClO4·H2O (1) and [Co(L)NH3]PF6·H2O (2). Based on infrared and electronic spectra, the complex 1 was revealed to have a square-pyramidal configuration with the pendant sulfur coordination at the apex. The structure of the complex 2 was determined by single-crystal X-ray analysis. The molecule has a six-cooridnate structure with the coordination of the pendant sulfur and the ammonia molecule at the apical sites, the Co–S and Co–N(NH3) distances being ca. 2.25 and 2.0 Å, respectively. Electrochemical measurements (CV and DPP) for 2 and [Co(salen)(R-NH2)2]PF6 as the reference have revealed that the substitution of thioether sulfur for one of the apical amine ligands results in a positive shift of the CoIII/CoII redox potential. It is also found that the CoIII/CoII reduction of five-coordinate 1 occurs at a significantly high potential compared with six-coordinate 2 and [Co(salen)(R–NH2)2]PF6.
Interaction of Cationic Drugs with Nafion on Electrode Surfaces and Its Applicability to Determination of Electroinactive Drugs
Authors: Matsue Tomokazu , Aoki Atsushi , Uchida Isamu , Osa Tetsuo
Published: July 2006

The interaction of several electroinactive cationic drugs (hexamethonium, quinidine, neostigmine, nicotine and acetylcholine) with Nafion and the applicability of Nafion-coated electrodes to determination of the drugs have been investigated. The addition of a drug to an electrolyte solution containing (ferrocenylmethyl)trimethylammonium (FA+) induced a decrease in the peak current and a shift in the apparent half-wave potential of a cyclic voltammogram for FA+. The decrease in the peak current has been used for determination of the drugs at low concentrations less than 10−3 mol dm−3. The ion-selectivity coefficients of Nafion for the drugs have been determined by an electrochemical method. These drugs showed quite large values and the values seemed to be dependent on the hydrophobicity of the drugs.
Synthesis and Structural Studies of Remirol
Authors: Yamaguchi Seiji , Takai Mayumi , Hanazome Isao , Okada Yûko , Kawase Yoshiyuki
Published: July 2006

One step cyclization of 2′,4′,6′-trihydroxyacetophenone with 1,4-dibromo-2-methyl-2-butene gave two 2-isopropenyl-2,3-dihydrobenzofuran-4,6-diols and a new 3-methyl-2,5-dihydro-1-benzoxepin-6,8-diol. The structure of natural remirol was confirmed by comparison with monomethylated compounds of the former products. Racemic remirol was synthesized from 3,5-dimethoxyphenol in three steps.
High-Pressure Cycloaddition Reaction of Tropone with Furans
Authors: Sugiyama Shigeru , Tsuda Tohru , Mori Akira , Takeshita Hitoshi , Kodama Mitsuaki
Published: July 2006

Thermal reactions of tropone with furan and 2-methoxyfuran mainly gave the endo-[4+2] cycloadducts, the kinetically controlled products, at 3000 bar. In the latter case, the product further reacted with tropone to yield 2:1-adducts. On the other hand, the reaction with 3,4-dimethoxyfuran under similar conditions yielded mainly the exo-[4+2] adducts, the thermodynamically controlled products. The predominant formation of the endo-Diels–Alder adducts with furans under the high-pressure conditions may be valuable from a synthetic point of view.
The 1,3-Dipolar Cycloaddition Reactions of Heteroaromatic Dicyanomethylides with Phenylsulfinylethene and Bis(trimethylsilyl)ethyne: Synthesis of 1,2-Unsubstituted 3-Cyanoindolizines
Authors: Matsumoto Kiyoshi , Uchida Takane , Ikemi Yukio , Tanaka Toshio , Asahi Momoyo , Kato Tomoe , Konishi Hideyuki
Published: July 2006

Pyridinium and diazinium dicyanomethylides underwent 1,3-dipolar cycloaddition-extrusion reactions with phenylsulfinylethene, producing the corresponding 3-cyanoindolizines in moderate to good yields. 1,3-Dipolar cycloadditions of these ylides with bis(trimethylsilyl)ethyne gave either the 1,2-bis(trimethylsilyl)-3-cyanoindolizines or the 1-trimethylsilyl-3-cyanoindolizines, or mixtures of these, depending on the substituents and the presence of another nitrogen atom in the pyridine ring. 1,2-Bis(trimethylsilyl)-3-cyanoindolizines underwent regiospecific protodesilylation at the 2-position upon a treatment with silica gel in refluxing chloroform, yielding 1-trimethylsilyl-3-cyanoindolizines. The 1,2-bis(trimethylsilyl)-, and 1-trimethylsilyl-3-cyanoindolizines suffered from quantitative protodesilylation under catalysis by tetrabutylammonium fluoride to afford 1,2-unsubstituted 3-cyanoindolizines.
Regeneration of NADPH and Hydrogenation of Ketones to Alcohols with the Combination of Hydrogenase, Ferredoxin-NADP Reductase, and Alcohol Dehydrogenase
Authors: Okura Ichiro , Kurabayashi Katsumi , Aono Shigetoshi
Published: July 2006

The regeneration of nicotinamide–adenine dinucleotide phosphate (reduced form, NADPH) by the reduction of NADP by hydrogen gas was carried out with the [hydrogenase–ferredoxin-NADP reductase (FNR)] system. Ketone hydrogenation was tried by the combination of the above system and alcohol dehydrogenase (ALDH), as shown in the following scheme:

(Remark: Graphics omitted.)

In the [hydrogenase–FNR] system, NADP was easily reduced by hydrogen to form NADPH. By adding ALDH to the above system, the hydrogenation of ketone to alcohol was observed. The ketones used in this study were 2-butanone, 2-pentanone, and 2-hexanone. After 8 h, the turnover number of NADP was 13 for 2-butanone, 15 for 2-pentanone, and 10 for 2-hexanone, showing a recurrence of NADP by hydrogen gas.
Anodic Cyanation of 1-Methylimidazoles
Authors: Yoshida Kunihisa , Kitabayashi Hirohito
Published: July 2006

The electrooxidation of several 1-methylimidazoles was performed in MeOH that contains NaCN at a platinum anode in a divided cell. Replacement of an aromatic hydrogen by a cyano group occurred. With 1,2,4,5-tetramethylimidazole, the 2,5-addition of cyano groups to the imidazole ring was achieved, and besides side-chain substitution occurred concurrently.
Asymmetric Allylation with a New Chiral Allylating Agent Prepared from Tin(II) Triflate, Chiral Diamine, and Allylaluminum
Authors: Minowa Nobuto , Mukaiyama Teruaki
Published: July 2006

A chiral allylating agent, readily generated from tin(II) trifluoromethanesulfonate (tin(II) triflate), chiral diamines derived from (S)-proline and allylaluminum, is efficiently employed in the asymmetric allylation of aldehydes and an epoxide. Reaction of a chiral 2-methyl-2-propenylating (methallylating) agent with aldehydes also proceeds smoothly to afford the corresponding homoallylic alcohols in good yields with high enantioselectivities. According to a similar procedure, asymmetric propargylation of aldehydes affords homopropargylic alcohols in good optical purities.
Preparation of New Nitrogen-Bridged Heterocycles. 16. Facile Synthesis of Thieno[2,3-b]indolizine Derivatives
Authors: Kakehi Akikazu , Ito Suketaka , Ohno Yasuhiro , Shiba Shouji , Kamata Sakashi
Published: July 2006

2-Ethoxycarbonyl-3-methyl- and 3-phenylthieno[2,3-b]indolizine derivatives were first synthesized in moderate to good yields by the treatment of tricyclic 5,5a-dihydropyrido[2,1-c]thieno[3,2-e][1,4]thiazines with a dehydrogenating agent. In contrast to the cases of bicyclic 1,9a-dihydropyrido[2,1-c][1,4]thiazines, all of the thienoindolizines obtained here were rearranged products and no desulfurized product could be obtained.
Autoxidation of 1-Methyl- and 1,3-Dimethylazulenes in Polar Aprotic Solvents: Structural Proof for Products and Reaction Pathways
Authors: Takekuma Shin-ichi , Matsubara Yoshiharu , Yamamoto Hiroshi , Nozoe Tetsuo
Published: July 2006

Autoxidation of the title azulenes at 100 °C in HMPA or DMF afforded a wide variety of products: Namely, the oxidation products of the side-chains, 1-substituted azulenes, 1H-inden-1-ols, naphthoquinones, benzenoids, and dimeric and trimeric compounds, with or without rearrangements. 1H NMR (200-MHz) parameters of various azulene derivatives are given for comparative study. Possible reaction pathways for the formation of these products are discussed in comparison with the results of the previous studies on guaiazulene and 4,6,8-trimethylazulene.
Effect of Substituents on the Oxidation Potential of Phthalocyanines and Electrocrystallization
Authors: Orihashi Yuji , Nishikawa Michinori , Ohno Hiroyuki , Tsuchida Eishun , Matsuda Hiro , Nakanishi Hachiro , Kato Masao
Published: July 2006

A series of tetra- or octasubstituted phthalocyaninatocobalt derivatives were prepared and their oxidation behaviors were examined in relation to the nature of substituents. The oxidation potentials of phthalocyanines, especially those of rings were affected by the nature of both substituents and axial ligands. These oxidation potentials were in a linear relation with the Hammett’s constants for substituents or axial ligands. The electrocrystallization proceeded when an oxidation potential higher than that for the phthalocyanine ring was given to the solution. This potential shift was therefore revealed to be an important factor to control the electrocrystallization of these phthalocyanines.