bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Chiral 18-Crown-6 Derivatives and Dibenzocrown Ethers Incorporating trans-Tetrahydrofuran-2,5-diylbis(methylene) Units of Known Absolute Configuration
Authors: Naemura Koichiro , Ebashi Iwao , Matsuda Atsushi
Published: July 2006

By using (−)-trans-2,5-bis(hydroxymethyl)tetrahydrofuran (1) of known absolute configuration as a chiral diethylene glycol unit, 18-crown-6 derivatives 8, 9, 12, and dibenzocrown ethers 14, 15 containing trans-tetrahydrofuran-2,5-diylbis(methylene) unit were prepared in enantiomerically pure forms. Their abilities to extract alkali metal picrates were investigated.
Behavior of Polyacrylamide–Acyclic Poly(oxyethylene)-coated Ion-selective Electrodes in Nonaqueous Solvents
Authors: Nakamura Toshio , Ogiwara Kazuyuki , Izutsu Kosuke , Rechnitz G A
Published: July 2006

Ion-selective electrodes constructed with polyacrylamide(PAA) coupled to acyclic poly(oxyethylene) neutral carriers, tetraethylene glycol monododecyl ether (POE4) or hexaethylene glycol monododecyl ether (POE6), were reported. Nernstian responses were obtained to magnesium and barium ions in AN with the PAA–POE4 membrane and to copper(II) and silver(I) ions in DMSO with the PAA–POE6 membrane.
Paramagnetic Cobalt(III) Complexes with Organic Ligands. X. The Preparation and Properties of Radical Diamminebis(5-nitrosalicylideneaminato)cobalt(III) Complex and Biradical Diamminebis(5-nitrosalicylideneaminato)cobalt(II) Complex
Authors: Yamamoto Yoshihisa , Konno Hidetaka
Published: July 2006

From the reaction mixture of diamminebis(salicylideneaminato)cobalt(III) complex, (Remark: Graphics omitted.) (1) and 60% nitric acid, radical diamminebis(5-nitrosalicylideneaminato)cobalt(III) complex, (Remark: Graphics omitted.) (2), and biradical diamminebis(5-nitrosalicylideneaminato)cobalt(II) complex,(Remark: Graphics omitted.) (3), have been isolated and characterized by analytical, magnetic, spectroscopic, and XPS methods. The effective magnetic moments of 2 and 3 were 1.7 and 5.5 BM, respectively. In the IR spectrum of 2, a band due to the rocking deformation vibration of NH3 was observed at ca. 840 cm−1. The absorption spectra of 2 and 3 showed a strong absorption peak at ca. 690 nm. In the XPS, Co 2p spectra for 3 showed strong satellites, indicating the oxidation number of the cobalt to be +2, whereas no satellites were observed for the other complexes. In comparison with diamagnetic cobalt(III) complex, (Remark: Graphics omitted.) (4), C 1s spectra for 2 and 3 showed much larger shoulders on the higher binding energy side due to the electron-poor carbons. It suggests the presence of an unpaired spin on ligands in accordance with paramagnetism of the complexes.
The Thermal Decomposition of Lead cyclo-Tetraphosphate
Authors: Nariai Hiroyuki , Motooka Itaru , Kanaji Yukio , Tsuhako Mitsutomo
Published: July 2006

The process of the thermal decomposition of lead cyclo-tetraphosphate dihydrate (P4m), Pb2P4O12·2H2O, was investigated using X-ray analysis, DTA-TG, HPLC, Isotachophoresis (IP), and IR spectrometry. P4m lost water of crystallization at about 100 °C. In the region of 150–170 °C, P4m decomposed to form oligo phosphates, and at about 190 °C, oligo phosphates changed to a crystalline material which contained ortho- and triphosphate. At about 300 °C, the crystalline material changed to cyclo-octaphosphate (P8m) through a new type of cyclo-tetraphosphate (P4m*). However, in the presence of a higher water-vapor pressure than the atmospheric one, the crystalline material changed mainly to the new type of P4m* with a little P8m, while at a low water-vapor pressure, the reverse tendency was observed: mainly P8m and a little P4m*.
Synthesis of a 24-Epimeric Mixture of 4α,14α,24-Trimethyl-9(11)-cholesten-3-one
Authors: Yamashita Masahiko , Naora Misuzu , Murae Tatsushi , Tsuyuki Takahiko , Takahashi Takeyoshi
Published: July 2006

A 24-epimeric mixture of 4α,14α,24-trimethyl-9(11)-cholesten-3-one was synthesized from lanosterol through 4α,14α,24-trimethyl-8-cholesten-3β-ol and 4α,14α,24-trimethyl-7,11-dioxocholestan-3β-yl acetate as key intermediates.
Novel Base-Promoted Rearrangement of 2-(4-Cyano-, 2-Nitro-, and 4-Nitrobenzyloxy)tropones and 2-(2-Oxo-2-phenethyloxy)tropone to 2-[(4-Cyano-, 2-Nitro-, and 4-Nitrophenyl)hydroxymethyl]tropones and 2-(1-Hydroxy-2-oxo-2-phenethyl)tropone
Authors: Takeshita Hitoshi , Mori Akira , Suizu Hiroshi
Published: July 2006

The base-catalyzed rearrangement of 2-(2-nitro-, 4-nitro-, and 4-cyanobenzyloxy)tropones smoothly yielded corresponding 2-[(aryl)hydroxymethyl]tropones, while their thermolysis gave 3-(arylmethyl)tropolones. This reaction has no precedent analogy in troponoid chemistry, and this rearrangement is widely applicable to the 2-troponyl ethers of alcohols carrying an electron-attractive substituent on the α-position, as was verified by the occurrence of 2-(1-hydroxy-2-oxo-2-phenethyl)tropone from 2-(2-oxo-2-phenethyloxy)tropone.
Cycloaddition of Pyridinium Methylides with Electron-Deficient Olefins and Silica-Gel Mediated Elimination of Pyridines from the Cycloadducts: A New Method of Alkylation or Hydroalkylidenation of Olefins
Authors: Tsuge Otohiko , Kanemasa Shuji , Takenaka Shigeori
Published: July 2006

Pyridinium methylides bearing an anion-stabilizing substituent at the ylide carbon react with a variety of olefins carrying two electron-withdrawing groups at the both carbons such as N-substituted maleimides, a citraconimide, dimethyl maleate, dimethyl fumarate, and 1,2-dibenzoylethene. The cycloadducts thus formed undergo a ready elimination of pyridines when treated with silica gel. This sequence is a new method for alkylation or hydroalkylidenation of olefins.
Thermoelectric Conversion by Thin-Layer Thermogalvanic Cells with Soluble Redox Couples
Authors: Ikeshoji Tamio
Published: July 2006

Thermogalvanic cells containing a redox couple of [Fe(CN)6]4−⁄3− or Fe2+⁄3+ as an electroactive species were built for thermoelectric conversion from low-grade heat with a temperature less than 100 °C. The distance between high- and low-temperature electrodes was set to 1 mm in order to produce a high power density. Thermoelectric powers, inner resistances, and heat fluxes of the cells, which were placed horizontally (i.e. in which the temperature gradient was vertical) were measured under steady state conditions. Natural convection, which was induced by a temperature difference and current flowing in appropriate directions, produced lower inner resistances than those with no convection by several times. It had only a small effect on thermoelectric powers and heat-transfer coefficients. Thus, both the power densities and the thermal efficiencies increased by nearly one order of magnitude due to the convection. A power density of 2.6 W m−2 was obtained during steady state using a cell containing an aqueous solution of 0.13 mol dm−3 K4[Fe(CN)6] and 0.85 mol dm−3 K3[Fe(CN)6] at a temperature difference of 72 K and a thermal efficiency of 6.7×10−5; the upper electrode was kept at a lower temperature.
Synthesis, and Crystal and Molecular Structure of Heptaaquabis (1-hydroxy-2-naphthoato)lanthanum(III) 1-Hydroxy-2-naphthoate Hydrate and the Isomorphous Neodymium(III) Salt, [M{C10H6(OH)CO2}2(H2O)7][C10H6(OH)CO2]·H2O (M=La, Nd)
Authors: Ohki Yoshiyuki , Suzuki Yasuo , Ouchi Akira
Published: July 2006

The light lanthanoid(III) (La or Nd) 1-hydroxy-2-naphthoate crystals indicated in the title were obtained and their structures were determined by the X-ray diffraction method using their single crystals. They are orthorhombic with the space group P212121, Z=4. The unitcell axis lengths of the lanthanum(III) complex are: a=11.985(4), b=40.21(5), and c=7.017(1) Å. The central metal atom is ennea-coordinated and is in a tricapped trigonal-prism geometry, where two carboxylate ions act as the unidentates, and the other coordinating positions are occupied by water oxygen atoms. The non-coordinated carboxylate ion is hydrogen-bonded to two ligated water oxygen atoms with its respective carboxylato oxygen atoms. The complex molecules are not directly bridged by the carboxylate ions, but the complexes are linked by hydrogenbondings in the a- and c-axis directions. Such hydrophilic and the hydrophobic layers of the naphthalene rings, both of them being parallel to the ac-plane, are laid alternately in the crystal.
The Catalytic Electroreduction of Oxygen in an Aqueous Solution on Glassy Carbon Electrodes Covalently Modified with [5,10,15,20-Tetrakis(4-carboxyphenyl)porphinato]iron(III)
Authors: Arifuku Fumihiro , Iwatani Keizo , Ujimoto Kikujiro , Kurihara Hirondo
Published: July 2006

The catalytic electroreduction of an oxygen molecule on a glassy carbon electrode covalently modified with [5,10,15,20-tetrakis(4-carboxyphenyl)porphinato]iron(III) (abbreviated as GC-O-Fe(III)TCPP) was investigated in an aqueous solution. The reduction of oxygen on the GC-O-Fe(III)TCPP electrode occurs at a more anodic potential than on the glassy carbon electrode adsorbing Fe(III)TCPP. This anodic shift of the oxygen reduction potential may be closely related to the number of bonds between a metalloporphyrin molecule and the electrode material. The oxygen molecule is reduced via the one-step reduction accompanying four-electron and four-proton transfer at pH 7–11 and via two successive reductions accompanying two-electron transfer and subsequently two-electron and four-proton transfer at pH>11.5. At pH<6, the number of transferred electron could not be reproducibly determined because of the cleavage of several ester linkages.
Asymmetric Synthesis of (+)-Phosphinothricin and Related Compounds by the Michael Addition of Glycine Schiff Bases to Vinyl Compounds
Authors: Minowa Nobuto , Hirayama Masao , Fukatsu Shunzo
Published: July 2006

(S)-(+)-Phosphinothricin was prepared in good optical yield by the Michael addition of chiral glycine Schiff base derived from (S)-2-hydroxy-3-pinanone to vinyl phosphorus compound. (R)-(−)-Phosphinothricin, an enantiomeric isomer, can also be prepared from the same chiral glycine Schiff base by choosing suitable reaction temperature.
A New Synthesis of Cyclic Ureas, Cyclic Urethanes, and a Quinazolinedione. Selenium-Assisted Carbonylation of Aromatic Amines with Carbon Monoxide
Authors: Yoshida Tohru , Kambe Nobuaki , Murai Shinji , Sonoda Noboru
Published: July 2006

Five-, six-, and seven-membered cyclic ureas were synthesized in excellent yields from various aromatic diamines by reaction with carbon monoxide and a stoichiometric or excess amount of selenium in the presence of N-methylpyrrolidine. The carbonylation also proceeded using a catalytic amount of selenium in the presence of an oxidizing agent such as oxygen or dimethyl sulfoxide producing selectively the five and six-membered cyclic ureas. In the case of 2-(2-aminoethyl)aniline under the catalytic conditions, intra- and intermolecular carbonylation competed resulting in the formation of a mixture of the seven-membered cyclic urea, 1,3,4,5-tetrahydro-2H-1,3-benzodiazepin-2-one and the acyclic urea, 1,3-bis[2-(2-aminophenyl)ethyl]urea. The distribution ratio of these two products varied depending on the reaction conditions, but selective formation of the cyclic urea was attained only when a stoichiometric or excess amount of selenium was used. In addition to the above diamino compounds, 2-carbamoylaniline, 2-amino-3-pyridinol, and 2-(hydroxymethyl)aniline also underwent similar carbonylation to give 2,4(1H,3H)-quinazolinedione, oxazolo[4,5-b]pyridin-2-(3H)-one, and 1,4-dihydro-2H-3,1-benzoxazin-2-one, respectively.
The Molecular Structure of (+)589-β2-(3-Methyl-2-iminobutanoato) ((2S,10S)-4,8-diazaundecane-2,10-diamine)cobalt(III) Perchlorate: α-Imino Acidato Complex
Authors: Yamaguchi Motowo , Yamagishi Takamichi , Hida Mitsuhiko
Published: July 2006

The crystal structure of (+)589-β2-(3-methyl-2-iminobutanoato)((2S,10S)-4,8-diazaundecane-2,10-diamine)cobalt(III) perchlorate has been determined by the single-crystal X-ray diffraction method. The complex ion adopts Λ-β2 configuration, and it has the Co–N(imine) bond length of 1.90 Å, which is shorter than the Co–N(amine) bond lengths. The chelate ring of the 2-imino carboxylato is planar.
The Determination of a Small Amount of a Biological Constituent by the Use of Chemiluminescence. XI. The Determination of Protein Using a 1,10-Phenanthroline–Hydrogen Peroxide–Osmium(VIII) System
Authors: Hara Tadashi , Tsukagoshi Kazuhiko
Published: July 2006

Osmium(VIII) was found by the authors to show extremely sensitive catalytic activity for the 1,10-phenanthroline–hydrogen peroxide chemiluminescence system. By optimizing the measurement conditions, 3.2×10−11–1.3×10−8 mol dm−3 osmium(VIII) could be determined by chemiluminescence flow-injection analysis with a detection limit of 0.4 pg. The method for the determination of protein was established; it was based on the lowering of the catalytic activity of osmium(VIII) attributable to the complex formation between osmium(VIII) and protein. Similar calibration curves were obtained for bovine serum albumin, human serum albumin, and human serum γ-globulin under the optimum conditions for the determination of protein. According to the method, 5.0×10−6–1.0×10−3 g dm−3 protein could be determined with a detection limit of about 250 pg and with a coefficient of variation of 2.9% (n=10) for a 1.0×10−4 g dm−3 protein solution.
Calorimetric and Spectrophotometric Studies of Ternary Copper(II) Complexes with Bromide Ions and 2,2′-Bipyridyl in N,N-Dimethylformamide
Authors: Ishiguro Shin-ichi , Nagy László , Ohtaki Hitoshi
Published: July 2006

Mixed ligand complexation of copper(II) with bromide ions and 2,2′-bipyridyl (bpy) has been calorimetrically studied in N,N-dimethylformamide (DMF) containing 0.16 mol dm−3 (C2H5)4NClO4 at 25°C. Complexation of the metal ion with 2,2′-bipyridyl has been also studied in the same solution. The calorimetric titration curves obtained were satisfactorily explained in terms of formation of the mononuclear [CuBrp(bpy)q](2−p)+ (denoted as (1pq)) complexes such as (101), (102), (103), (111), (121), and (112), and their formation constants and enthalpies were determined. The mixed ligand (111), (112), and (121) complexes are quite stable and yielded to a large extent in the DMF solution. Electronic spectra of these complexes have been measured in DMF over the range 400–1500 nm. The thermodynamic quantities of formation and electronic spectra of the complexes thus obtained are discussed in connection with the coordination structure of the complexes in DMF. The formation of the five-coordinate [Cu(bpy)2(dmf)]2+ and [CuBr(bpy)2]+ complexes is suggested in the DMF solution as well as in crystal.
Basic Autoxidation of Friedelin
Authors: Nishihama Tadaaki , Takahashi Takeyoshi
Published: July 2006

Base-catalyzed autoxidation of a triterpene ketone, friedelin, in the presence of potassium t-butoxide gave four products, and their structures and formation mechanism were investigated. The common intermediate to these compounds was suggested to be 4-hydroperoxyfriedelan-3-one, not friedelane-2,3-dione. 3-Oxafriedel-1-ene-2-carboxylic acid was a dehydration product of the main product, 2-hydroxy-3-oxafriedelane-2-carboxylic acid.
Kinetic Studies of Antioxidant Activity of New Tocopherol Model Compounds in Solution
Authors: Mukai Kazuo , Yokoyama Satoshi , Fukuda Kazuyuki , Uemoto Yuichi
Published: July 2006

The second-order rate constants ks for the reaction of 10 kinds of tocopherol (vitamin E) model compounds with stable phenoxyl radical in ethanol have been measured at 25.0°C, using a stopped-flow spectrophotometer, as a model reaction of tocopherols with unstable free radicals (ROO·, RO·, and HO·) in biological systems. The absolute ks values of α-, β-, γ-, and δ-tocopherol models are similar to or slightly smaller than those of the corresponding tocopherols having a long-phytyl-chain. The relative ks values (α: β: γ: δ=100 : 53 : 50 : 24), that is, relative antioxidant activities, of α-, β-, γ-, and δ-tocopherol models are in good agreement with those (100 : 44 : 47 : 20) of α-, β-, γ-, and δ-tocopherols. The antioxidant activities of tocopherol models having two alkyl substituents, such as methyl, ethyl, isopropyl, and t-butyl groups, at ortho positions of OH group are similar to each other, suggesting that the effect of steric hindrance on the reaction rate is small. 5,7-Dimethyltocol model has quite similar rate constants with those of β- and γ-tocopherol models, whereas δ-tocopherol model is only ca. 24% as reactive as α-tocopherol model and tocol model is only ca. 10% as reactive as α-tocopherol model. The result indicates that the rate constants increase as the total electron donating capacity of the alkyl substituents at aromatic ring increases. For the tocopherol models logks was found to correlate with Σσ+ substituent constants with a ρ+ value of −1.0.
Electrogenerated Acid-Catalyzed Reactions of Acetals, Aldehydes, and Ketones with Organosilicon Compounds, Leading to Aldol Reactions, Allylations, Cyanations, and Hydride Additions
Authors: Torii Sigeru , Inokuchi Tsutomu , Takagishi Sadahito , Horike Hirofumi , Kuroda Hideki , Uneyama Kenji
Published: July 2006

Exquisite use of electrogenerated acid (EG acid) in the silicon-mediated acid-catalyzed reactions; e.g., aldol reactions, allylations, cyanations, and hydride additions is described. The aldol reaction of acetals 1 with enol trimethylsilyl ethers 3 and 1,2-bis(trimethylsiloxy)alkenes 4 gives the corresponding adducts 5 and 6, respectively. The reaction proceeds smoothly with EG acid derived from perchlorate salts such as LiClO4, n-Bu4NClO4, and Mg(ClO4)2 in dichloromethane using platinum electrodes. The amount of electricity required to complete the reaction implies a cationic process which is mediated by the trimethylsilyl moiety. This aldol reaction is further developed with unprotected carbonyl compounds 2 with 3, giving the trimethylsilyl ethers of the adducts 7. Further utility of this EG acid as a catalyst for a chain reaction is exemplified by the successful application in the following conversions: (1) The allylation of acetals 1 with allyltrimethylsilane (8) to give 9, (2) the cyanation of acetals 1 and unmasked 2 with trimethylsilyl cyanide (10) to give 11, 12, and 13, and (3) the hydride addition of acetals 1 with triethylsilane (14) to give 15.
Studies on Dissolved Metalloenzymes in Lake Water. III. Correlation between Dissolved Alkaline Phosphatase and Orthophosphate in Lake Water
Authors: Kobayashi Kensei , Iwase Kimikazu , Hashimoto Shinya , Ueda Hirotaka , Fujiwara Kitao , Otsuki Akira , Fuwa Keiichiro , Haraguchi Hiroki
Published: July 2006

Alkaline phosphatase activity (both dissolved and total) in Lake Kasumigaura was determined periodically together with concentrations of phosphorus compounds therein. Distinct negative correlation was found between the dissolved alkaline phosphatase activity and the orthophosphate concentration during the phosphorus-limited season. The decrease of the concentration of dissolved alkaline phosphatase was observed at the level of 1 ng ml−1 of orthophosphate. The present results suggest that both alkaline phosphatase in vivo and dissolved alkaline phosphatase in the lake water play important roles in phosphorus cycles in natural water.
Geochemical Characterization of Geological Standard Rock Samples from Rare Earth Element Distribution Patterns Measured by Inductively Coupled Plasma Atomic Emission Spectrometry
Authors: Toyoda Kazuhiro , Haraguchi Hiroki
Published: July 2006

Rare earth elements (REEs) in twelve standard rock samples have been determined by inductively coupled plasma atomic emission spectrometry after separation of diverse metal ions with cation exchange resin. These rock samples are old six standard rocks (W-1, BCR-1, AGV-1, GSP-1, JB-1, JG-1) and new six standard rocks (JB-2, JB-3, JA-1, JR-1, JR-2, JGb-1) issued from the Geological Survey of Japan. These samples are various types of igneous rocks, which show various shapes of the REE distribution patterns. Geochemical characteristics of these standard rock samples will be discussed from the relationships between rock types and the shapes of the REE pattern.
27Al NMR Study on the Interaction between Aluminate and Silicate Ions in Alkaline Solution
Authors: Yokoyama Takushi , Kinoshita Setsuko , Wakita Hisanobu , Tarutani Toshikazu
Published: July 2006

An interaction between aluminate and silicate ions in highly alkaline solution was investigated by a high-resolution 27Al NMR study. The interaction greatly varied with alkali concentration, and did not occur at 1.0 mol dm−3 NaOH. At 0.10 mol dm−3 NaOH, the formation of a monomeric species with an ≡Al–O–Si≡ bond (Si/Al=1) was suggested and the formation constant was estimated to be 22.8 dm3 mol−1. At 0.015 mol dm−3 NaOH, polynuclear species with ≡Al–O–Si≡ bond was expected to be formed.
Convenient Optical Resolution of Axially Chiral 1,1′-Binaphthyl-2,2′-dicarboxylic Acid
Authors: Kanoh Shigeyoshi , Hongoh Yukihiko , Motoi Masatoshi , Suda Hiroshi
Published: July 2006

Axially chiral 1,1′-binaphthyl-2,2′-dicarboxylic acid was conveniently resolved through its brucine salts in satisfactory yields. The resolved diacids were confirmed to be optically pure from high-performance liquid chromatographic analyses of the dimethyl esters derived from them on an optically active poly(diphenyl-2-pyridylmethyl methacrylate) column.
Palladium-Catalyzed Double-Carbonylation of Alkenyl Halides with Secondary Amines To Give α-Keto Amides
Authors: Son Tae-il , Yanagihara Hisayoshi , Ozawa Fumiyuki , Yamamoto Akio
Published: July 2006

The double-carbonylation reaction of alkenyl halides with diethylamine in the presence of palladium catalysts has been examined in detail. The reaction gives α-keto amide together with amide, the single-carbonylation by-product. The yield of α-keto amide is strongly dependent on the nature of alkenyl halide. Alkenyl bromides or iodides having phenyl group(s) as substituent(s) on the vinyl group are successfully double-carbonylated under appropriate reaction conditions and the corresponding α-keto amides are obtained in good to modest yields together with amides. In contrast, the reactions of alkenyl halides without a phenyl group give amides exclusively. In order to clarify the reason for the substrate-specificity in the reaction, series of alkenyl- and alkenoylpalladium(II) complexes, the presumed intermediates in the catalytic reactions, have been prepared and their reactions with secondary amines, carbon monoxide, and alkenyl halides were examined. The study suggests the operation of three types of processes for amide formation in the catalytic reactions. Possible mechanisms for amide as well as α-keto amide formation are discussed.
Sorption of Uranyl Ions on Hydrous Oxides. A New Surface Hydrolysis Model
Authors: Gupta Anand Ram , Venkataramani Balakrishnan
Published: July 2006

Sorption of uranyl ions on hydrous titanium oxide(HTiO), magnetite(MAG), and hydrous thorium oxide(HThO) has been studied as a function of pH. Hydrous oxides have been characterized by their pH-titration curves, intrinsic dissociation constants(pKai*) and point of zero charge (pHpzc). The fraction of protonated surface hydroxyl groups as well as the surface pH(pHsurf) as a function of solution pH have been computed. The distribution of various hydrolyzed species of uranyl ions with solution pH have been compared with uranyl sorption isotherm on these oxides. Sorption edge in all the cases occurs when free hydroxyl groups are available on the surface and pHsurf is sufficiently high to favor the formation of dimer-like species on the surface. A new model for the sorption process, called surface hydrolysis model, which explains these and other features of uranyl sorption on hydrous oxides has been proposed. The model visualizes the sorption process as linking of uranyl ions with two adjacent free surface hydroxyl groups without deprotonation (provided the surface pH is high for the hydrolysis of uranyl ions) and formation of dimer-like structures on the surface. The new model has been successfully applied to the present and other available data on uranyl ion sorption on hydrous oxides.
Synthesis of 1,2,5a-Triazacyclohept[a]azulen-5(2H)-ones
Authors: Abe Noritaka , Emoto Yoshifumi
Published: July 2006

Reactions of 2-hydrazino-1-azaazulenes with acetylacetone gave 2-(3,5-dimethyl-1-pyrazolyl)-1-azaazulenes. Cyclizations of diethyl (1-azaazulen-2-yl)hydrazinomethylenemalonates in refluxing t-butylbenzene or on silica gel gave 1,2,5a-triazacyclohept[a]azulen-5(2H)-ones.
Molecular and Crystal Structure of the Lipid-Model Amphiphile, Dioctadecyldimethylammonium Bromide Monohydrate
Authors: Okuyama Kenji , Soboi Yoshie , Iijima Naomi , Hirabayashi Kiyoshi , Kunitake Toyoki , Kajiyama Tisato
Published: July 2006

Dioctadecyldimethylammonium bromide monohydrate (2C18N+2C1Br−·H2O), C38H80NBr·H2O, was crystallized from its solution in chloroform and hexane. The crystals are triclinic with the space group P\bar1, Z=2, a (normal to the bilayer surface)=3.811(2), b=0.7890(2), c=0.7418(2) nm, α=104.37(3), β=103.06(4), and γ=74.93(3)°. The structure was solved by the direct method and refined by the block-diagonal least-squares procedure: R=0.08 for 3121 observed reflections. The crystal structure consists of bimolecular layers stacking regularly along the a-direction. The two amphiphile molecules in the unit cell are related by centrosymmetry and pack tail to tail in a bilayer structure with tilting hydrocarbon chains by about 45° to the bilayer surface. The packing cross section per molecule in the layer plane is 0.567 nm2. The hydrocarbon chains pack with an triclinic (T//) subcell with dimensions of as=0.42, bs=0.49, cs=0.26 nm, αs=88, βs=104, and γs=111°. One of the two alkyl chains bends near the nitrogen atom and conforms a part of a head region. Two water oxygen atoms with half occupancies were found in an asymmetric unit and accomodated statistically in a unit cell. These water molecules are linked with bromide anions by hydrogen bonds with the distance of about 0.34 nm. Bromide anions and ammonium cations are on the same plane parallel to the bilayer surface.
Study of Ion Transport across Amphoteric Ion-Exchange Membrane. V. Nonequilibrium Thermodynamic Analyses of Ion Selectivity
Authors: Kaibara Kozue , Inoue Hiroyoshi , Tsuruyama Shigeru , Kimizuka Hideo
Published: July 2006

Ion-transport processes across an amphoteric ion-exchange membrane were investigated by means of estimating the membrane permeability matrix, a set of modified linear phenomenological coefficients, from the electrochemical and the ion flux data. Systematic comparisons of phenomenological analyses on an amphoteric ion-exchange membrane system with those on an ordinary cation-exchange membrane system were carried out to investigate the correlations of singly- and binary-charged membrane structures to characteristic transport properties. The modes of ion permselectivity of an amphoteric ion-exchange membrane in the metal chloride concentration-cell systems are characterized by the potentiometric selective response due to the ion-sieve effect, the low membrane conductance, and the large ion flux, while those of an ordinary cation-exchange membrane are characterized by the totally charge-dependent potential response, the high conductance, and the extremely small ion flux. The cross elements of the membrane permeability matrix, which represent the partial contributions of cation-anion interactions to the membrane permselectivity, are positive for an amphoteric membrane and negative for a cation-exchange membrane. The positive cross matrix elements act deceleratively on the membrane permeability, whereas the negative elements do acceleratively. It was pointed out based on the nonequilibrium thermodynamic theory that the preferable and efficient permeation mechanism is the simple diffusion process in an amphoteric ion-exchange membrane, whereas the electroconductive process in a cation-exchange membrane.
H2 Evolution from Various Aqueous Solutions over Thermally Reduced TiO2 and Pt–TiO2 Powder
Authors: Kudo Akihiko , Domen Kazunari , Maruya Ken-ichi , Onishi Takaharu
Published: July 2006

The reduction of H2O (or H+) to form H2 by reduced TiO2 and Pt–TiO2 was studied in distilled water and aqueous solutions of HCl, H2SO4, HNO3, and NaOH. Over the reduced TiO2 powder, H2 evolved moderately in distilled water and Ti3+ ions on the surface were presumed to be active sites for the reaction. The reaction in aqueous NaOH solution proceeded similarly to that in water while it was strongly suppressed in aqueous HCl and H2SO4 solutions. It was found that the suppression of H2 evolution is due to protons in the solution. Over reduced Pt–TiO2, H2 evolved rapidly from all solutions, except HNO3. In aqueous HNO3 solution, NO3− was reduced to NH3 over reduced TiO2 and Pt–TiO2.
Preparation and Characterization of (Tetrabenzoporphyrinato)nickel Hexafluoroarsenate, (NiTBP)3(AsF6)2(C10H7Cl). A New Type of Metallomacrocyclic Radical Salts
Authors: Yakushi Kyuya , Yoshitake Michiko , Kuroda Haruo , Kawamoto Atsushi , Tanaka Jiro , Sugano Tadashi , Kinoshita Minoru
Published: July 2006

Single crystals of a (tetrabenzoporphyrinato)nickel hexafluoroarsenate, (NiTBP)3(AsF6)2 were prepared by the use of an electrochemical technique. NiTBP is stacked one-dimensionally with a periodic unit composed of three macrocycles. This stacking mode is a new type among the one-dimensionally stacked macrocyclic complexes. The experimental results on reflectance spectrum and ESR indicate that this material is a one-dimensional semiconductor with a small electron correlation.
Structural Requirements for the Spatial Structure and Toxicity of Heat-Stable Enterotoxin (STh) of Enterotoxigenic Escherichia coli
Authors: Yamasaki Shinji , Hidaka Yuji , Ito Hideaki , Takeda Yoshifumi , Shimonishi Yasutsugu
Published: July 2006

The heat-stable enterotoxin (STh) of enterotoxigenic Escherichia coli consists of 19 amino acid residues and is linked intramolecularly by three disulfide bonds between Cys6 and Cys11, Cys7 and Cys15, and Cys10 and Cys18 (Y. Shimonishi et al., FEBS Lett., 215, 165 (1987)). The syntheses and biological assays of various analogs of STh with one or two of the three disulfide bonds showed that a disulfide bond between Cys7 and Cys15 and another between Cys6 and Cys11 or Cys10 and Cys18 are necessary for construction and stabilization of the spatial structure of STh to express its toxicity.
Preparation of Poly(p-phenylene) by Electrooxidative Polymerization in Acidic Media
Authors: Yamamoto Kimihisa , Asada Toshio , Nishide Hiroyuki , Tsuchida Eishun
Published: July 2006

The electro-oxidative polymerization of benzene in the presence of strong acids yields poly(p-phenylene) efficiently. A strong protonic acid such as trifluoromethanesulfonic acid or Lewis acid such as an aluminum trichloride forms a complex with benzene and reduces the oxidation potential of benzene to 1.7 V, which brings about the high current efficiency. The acids act both as an electrolyte and as a catalyst in this polymerization of benzene.
Relative Standard Electrode Potentials of I3−/I−, I2/I3−, and I2/I− Redox Couples and the Related Formation Constants of I3− in Some Pure and Mixed Dipolar Aprotic Solvents
Authors: Datta Jayati , Bhattacharya Abhijit , Kundu Kiron Kumar
Published: July 2006

Standard potentials of I3−/I− and I2/I3− redox couples relative to that of aqueous saturated calomel reference electrode SCE (W), ESCE(w) have been determined in propylene carbonate (PC), N,N-dimethylformamide (DMF), acetonitrile (ACN), and their binary mixtures at 25 °C from potentiometric measurements. The results helped evaluate the standard potentials of the redox couple I2/I− relative to ESCE(w) as well as the related formation constant (Kf) of I3− in these solvent systems. The solvent effects on the formation equilibrium I2+I−\ightleftharpoonsI3− were analyzed in the light of the transfer free energies of I2, ΔGt°(I2), as obtained from solubility measurements of I2 in the solvents, that of I−, ΔGt°(I−), as obtained earlier by use of the widely used TATB reference electrolyte assumption and that of I3−, ΔGt°(I3−), as obtained by subtracting these two contributions from the respective transfer free energies of formation equilibrium in the mixed solvents relative to a chosen reference solvent in each solvent system. The solvation behavior of these individual iodine species viz. I2, I−, I3− was interpreted in terms of involved interaction viz. Born, ion-dipole, ion-induced dipole, dispersion type soft–soft interactions, CTTS complexation and also the cavity effect as computed by the scaled particle theory (SPT).
Theoretical Study of Some Non-Benzenoid Hydrocarbons: Benzo[3′,4′]cyclobuta[1′,2′:6,7]cycloocta[1,2,3,4-def]biphenylene and Related Compounds
Authors: Pal Sukanta K , Gupta Archana Das , Das Gupta Nanda K
Published: July 2006

Benzo[3′,4′]cyclobuta[1′,2′:6,7]cycloocta[1,2,3,4-def]biphenylene (1), benzo[6,7]cycloocta[1,2,3,4-def]biphenylene (2), dibenzo[a,c]benzo[3,4]cyclobuta[1,2-f]cyclooctene (3), and biphenyleno[8′,1′:4,5,6,7]cycloocta[1,2-l]phenanthrene (4) have been studied by semiempirical SCFMO method of Pariser and Parr and Pople. Core resonance intergral values of Lo and Whitehead, Dewar et al. and Yamaguchi et al. have been used. It has been observed that π*←π spectra predicted by the methods of Lo and Whitehead and Chung and Dewar suitable for the prediction of ground state properties are in good agreement with experimental results and comparable to those predicted by the method of Yamaguchi et al. developed for the prediction of spectral transitions. For comparison values obtained by configuration interaction method has also been included. Resonance stabilization of the molecules has been studied along with other properties such as bond length, ionization potential, electron affinity, and half-wave reduction potential.
Coordination Selectivity in Aluminum(III) Complex with 8-Hydroxy-7-[(2-hydroxy-5-carboxyphenyl)azo]-5-quinolinesulfonic Acid: Evidence for Linkage Isomerism
Authors: Bai Zhi-Ping , Einaga Hisahiko , Hidaka Jinsai
Published: July 2006

The coordination reaction of 8-hydroxy-7-[(2-hydroxy-5-carboxyphenyl)azo]-5-quinolinesulfonic acid (hcqs) to aluminum(III) has been investigated spectrophotometrically in a weakly acidic aqueous solution (pH 2–5) with 0.1 mol dm−3 NaCl at 22.0 °C; the thermodynamic stability, kinetics, and mechanism of the formation of the aluminum(III) complex were deduced. The ligand rapidly coordinates to aluminum(III), with its 8-quinolinol (O–N) moiety, to form a yellow complex (metal:ligand=1:1), and then the complex slowly changes, via an intramolecular rearrangement, to a red complex with its dihydroxyazo (O-N-O) moiety, thus showing a linkage isomerism. In the first coordination process, the complex is formed mainly via a pathway of the reaction of AlOH2+ with Hhcqs3−. The coordination reaction mechanism of aluminum(III) with related ligands, 4-hydroxy-3-[(2-hydroxy-5-carboxyphenyl)azo]-1-naphthalenesulfonic and 7-[(4-carboxyphenyl)azo]-8-hydroxy-5-quinolinesulfonic acid, is also discussed.
Preparation of New Nitrogen-Bridged Heterocydes. 18. Facile Formations of 3-Arylpyrazolo[1,5-a]pyridines and 1-Arylindolizines
Authors: Kakehi Akikazu , Ito Suketaka , Kinoshita Naosumi , Abaka Yukio
Published: July 2006

The alkaline treatment of 1-[(substituted benzylthio)methyleneamino]pyridinium and 1-[2-(substituted benzylthio)vinyl]pyridinium bromides possessing an electron-withdrawing substituent such as a nitro or cyano group in the presence or absence of a dehydrogenating agent afforded the corresponding 3-arylpyrazolo[1,5-a]pyridines and 1-arylindolizines in moderate to good yields, while the reactions of the parent pyridinium salts and those having an electron-releasing group did not produce any significant products. The mode of the reaction, a ring contraction-desulfurization, is the same as that observed in related monocyclic species.
Indirect Electrolytic Oxidation of Thioamides Using Organotellurium as a Mediator
Authors: Matsuki Toshiaki , Hu Nan Xing , Aso Yoshio , Otsubo Tetsuo , Ogura Fumio
Published: July 2006

Bis(p-methoxyphenyl) telluride (1) electrochemically reacted with supporting electrolytes such as tetrabutylammonium acetate and tetraethylammonium tosylate under anhydrous conditions to give tellurium(IV) diacetate 2a and ditosylate 2b, respectively. On the other hand, 1 was electrolyzed in the presence of water to give telluroxide 3. It has turned out that the tellurium compounds 2a and 2b like telluroxide 3 are mild oxidizing agents, but 2b behaves differently in a reaction towards thioamide. Thus 2a and 3 converted it into nitrile, while 2b did it into 1,2,4-thiadiazole. An indirect electrolytic oxidation of thioamides with 1 as a mediator was examined under various conditions. As a result, nitriles or 1,2,4-thiadiazoles could be chemoselectively formed, depending on the intermediacy of 2a or 3 as an active species for the former and 2b for the latter.
Synthesis of 2-(1-Phosphorylalkyl)- and 2-(1-Alkenyl)furans through Nitrile Oxide Cycloaddition Route
Authors: Tsuge Otohiko , Kanemasa Shuji , Suga Hiroyuki
Published: July 2006

A new synthetic method of 2-(1-phosphorylalkyl)furans with a variety of substituents on the ring is presented. Cycloaddition of (diethoxyphosphoryl)acetonitrile oxide to O-protected allyl alcohols is followed by a simple sequential procedure including Raney Ni reduction and acid treatment to give 2-(1-phosphorylmethyl)furans. The phosphorus-stabilized carbanions derived from the phosphorus-functionalized furans are applied to alkylation, oxidation with oxygen, or olefination to provide 2-(1-phosphorylalkyl)furans, 2-acylfurans, or 2-(1-alkenyl)furans, respectively. Some other synthetic applications are also described.
New and Convenient Synthesis of 2-Substituted 2,3-Dihydro-1H-benz[de]isoquinolin-1-ones
Authors: Sato Ryu , Oikawa Katsuyuki , Goto Takehiko , Saito Minoru
Published: July 2006

Various 2-substituted 2,3-dihydro-1H-benz[de]isoquinolin-1-ones were obtained in high yields by chemoselective reduction of 2-substituted 1H-benz[de]isoquinoline-1,3(2H)-diones with sodium or zinc borohydride at room temperature.
Asymmetric Carbonyl Addition and Asymmetric Polymerization Assisted by Axially Chiral Diamines Give Disparate Ligand/Product Configurational Correlations
Authors: Kanoh Shigeyoshi , Muramoto Hiroki , Maeda Kazunobu , Kawaguchi Naotaka , Motoi Masatoshi , Suda Hiroshi
Published: July 2006

Organolithium reagents complexed with axially chiral biphenyl-substituted N,N,N′,N′-tetramethylethylenediamines (1 and 2) add to aldehydes in good enantioface selectivity. The pattern of the stereoselection, however, disagrees with that of the helical choice observed for the asymmetric polymerization of triphenylmethyl methacrylate with the same complexes.
Vacuum Sublimation Behavior of Molybdenum(VI) and Tungsten(VI) Chelates with 8-Quinolinol
Authors: Honjo Takaharu , Kawasaki Sumiko
Published: July 2006

A vacuum sublimation apparatus with a continuous-temperature gradient (30–280 °C) along the glass tube (60–0 cm) at 10−2 and 10−1 Torr (1 Torr=133.322 Pa) was used. 8-Quinolinol (Oxine, ox) and its Mo6+ and W6+ chelates (MoO2(ox)2 and WO2(ox)2) in milligram amounts were sublimed without any thermal decomposition. The Mo6+ chelate (orange yellow) forms large, rectangular crystals in the crossed state, while the W6+ chelate (pale yellow) forms small, rectangular crystals in the scattered states after vacuum sublimation.
Reaction of Rifamycin S with Hexahydro-1,3,5-triazines Prepared from Formaldehyde and Primary Aliphatic Amines
Authors: Taguchi Masahiro , Aikawa Norio , Tsukamoto Goro
Published: July 2006

Rifamycin S (1) and 25-O-deacetylrifamycin S reacted with 1,3,5-tri-t-butylhexahydro-1,3,5-triazine to give deep-blue compounds. The structures of the deep-blue compounds are discussed based on 13C NMR data, and it is concluded that the earlier structures should be partly re-revised. The mechanism of formation of the deep-blue compounds and the reaction of 1 with several hexahydro-1,3,5-triazines, which were prepared from formaldehyde and primary aliphatic amines, are also described.
Interference Effects of Helium on Motion of Xenon in Micropores of 5A Zeolites
Authors: Yasuda Yusuke , Shinbo Satoshi
Published: July 2006

Striking interference effects of He molecules on the motion of Xe in micropores of 5A zeolites have been found by the frequency response method. Results of the systems reveal that the absorbed Xe molecules may be divided into two abspecies, c1′ and c2′, in the presence of He molecules which were inert in a single component system: (i) at 273 K, c1′ diffuses faster and c2′ slower than pure Xe; (ii) at 255 K, c1′ diffuses faster than pure Xe, while the motion of c2′ is regarded as not diffusion but adsorption. The interference effects at 273 K have been explained quantitatively by decoupling a more general form of Fick’s law containing cross terms.
Excited-State Reactions of Coumarins in Aqueous Solutions. VI. Fluorescence Quenching of 7-Hydroxycoumarins by Chloride Ions in Acidic Solutions
Authors: Moriya Tetsuo
Published: July 2006

The fluorescence behavior of 7-hydroxycoumarin and 7-hydroxy-4-methylcoumarin has been studied in acidic aqueous solutions by changing the concentration of chloride ions as a fluorescence quencher. The intensity decrease and lifetime change in fluorescence from neutral and tautomeric forms of photo-excited states are explained by an interaction between protonated molecules generated in excited state and chloride ions. The magnitude of quenching-rate constant is estimated under steady-state conditions and the result is compared with the analysis using time-dependent response.
Dehydrooligopeptides. VIII. Convenient Syntheses of Various Dehydrotyrosine Derivatives Protected with Useful N, O-Protecting Groups via N-Carboxy Dehydrotyrosine Anhydrides
Authors: Shin Chung-gi , Yonezawa Yasuchika , Obara Takumi , Nishio Hiroaki
Published: July 2006

Various N-benzyloxycarbonyl (Cbz) O-protected dehydrotyrosine (ΔTyr) esters have been successfully synthesized mainly via two routes, in which reactions of (diethoxyphosphinyl)glycine ester with p-substituted benzaldehyde were included. Subsequent hydrolyses of the esters under various alkaline conditions were carried out in order to produce corresponding Cbz-ΔTyr-OH derivatives, which were further converted with thionyl chloride to give N-carboxy dehydrotyrosine anhydrides [ΔTyr·NCA]. In addition to these topics, the transformation of ΔTyr·NCA to various kinds of ΔTyr derivatives and a discussion on the configurational determination of all the new compounds are presented.
Liquid-Phase Dehydrogenation of 2-Propanol by Suspended Nickel Fine-Particle Catalyst
Authors: Noda Michio , Shinoda Sumio , Saito Yasukazu
Published: July 2006

Nickel fine particles that were prepared by a gas evaporation method were used to catalyze the liquid phase dehydrogenation of 2-propanol efficiently in the suspended state. Rate retardation due to the product acetone without catalytic-site deactivation was confirmed kinetically. High reaction rates were attained under the boiling conditions and a reasonable activation energy as well as adsorption heat of acetone was obtained. A useful application of the present catalytic process is proposed.
Diene-Transmissive Hetero Diels–Alder Reactions of 3-Oxo-1,4-pentadiene Equivalents Leading to Functionalized 2-Chromanones
Authors: Wada Eiji , Kanemasa Shuji , Tsuge Otohiko
Published: July 2006

Through hetero Diels–Alder reaction with a vinyl ether and Horner–Emmons olefination, diethyl 2-oxo-3-butenylphosphonate leads to 2-ethoxy-6-(1-alkenyl)-3,4-dihydro-2H-pyrans which are further transformed into 2-chromanones via regioselective Diels–Alder reactions with activated acetylenes followed by hydrolysis and oxidation.
Epoxidation of Alkenes Catalyzed by Iron(III) Schiff Base Chelates. A Monooxygenase Model
Authors: Jacob Mathew , Bhattacharya Pabitra Krishna , Ganeshpure Pralhad A , Satish Sheo , Sivaram Swaminathan
Published: July 2006

Iron(III) Schiff base chelates [Fe2(PA2ppd)2Cl4]Cl2 (1), [Fe2(PA2mpd)2Cl4]Cl2 (2), and [Fe(PA2opd)Cl2]Cl (3), were synthesized, where (PA2ppd), (PA2mpd), and (PA2opd) are the Schiff bases derived from 2-pyridinecarbaldehyde (PA), and p-phenylenediamine (ppd), m-phenylenediamine (mpd), and o-phenylenediamine (opd) respectively. The complexes 1, 2, and 3 catalyzed the epoxidation of alkenes with iodosylbenzene as an oxidant providing a chemical model for cytochrome P-450. The binuclear complexes (1, 2) were superior to the mononuclear complex (3) as the catalyst for epoxidation of norbornene. Addition of pyridine bases increased the rates, and yields of epoxidation.
Halogenation Using Quaternary Ammonium Polyhalides. XVII. Iodination of Acetanilide Derivatives with Benzyltrimethylammonium Dichloroiodate and Zinc Chloride
Authors: Kajigaeshi Shoji , Kakinami Takaaki , Watanabe Fumiko , Okamoto Tsuyoshi
Published: July 2006

The reaction of acetanilide derivatives with benzyltrimethylammonium dichloroiodate in acetic acid in the presence of ZnCl2 at room temperature or at 70 °C gave iodo-substituted acetanilide derivatives in good yields.
A 3-Methylene-1,2-dioxetane as a Possible Chemiluminescent Intermediate in Singlet Oxygenation of Allene
Authors: Akasaka Takeshi , Fukuoka Koichiro , Ando Wataru
Published: July 2006

Photosensitized oxygenation of bis(adamantylidene)methane and vinylideneadamantane at −78 °C afforded adamantanone and the former also emitted light when warmed up to room temperature in the presence of a fluorescer. A 3-methylene-1,2-dioxetane as a possible chemiluminescent intermediate is proposed.
Light-Induced Generation of Charge Carriers in Porphyrin Solids Doped with Electron-Accepting and Donating Molecules
Authors: Harima Yutaka , Yamamoto Kazuyo , Takeda Kazuhiko , Yamashita Kazuo
Published: July 2006

Fluorescence and photocurrent generation efficiencies of thin films of 5,10,15,20-tetraphenylporphyrin (TPP) and its zinc complex (ZnTPP) doped with electron-accepting and -donating molecules were investigated to get an insight into a charge-carrier generation in organic solid films upon irradiation. Photogeneration of charge carriers in I2-doped ZnTPP solids was found to consist mainly of a direct ionization process via an excited singlet state of ZnTPP while that in TPP solids was consistent with an exciplex formation model. From a practical view point, the doping of acceptor molecules into p-type porphyrin solids was effective to improve photovoltaic efficiencies of Al/porphyrin/Au sandwich-type cells.
Complexation of Lanthanoid(III) with Substituted Benzoic or Phenylacetic Acids and Extraction of These Acids
Authors: Hasegawa Yuko , Morita Yoko , Hase Masako , Nagata Mayumi
Published: July 2006

The stability constants of lathanoid(III) complexes with several benzoic and phenylacetic acids substituted with –OH, –OCH3, or –NH2 groups as well as the dissociation constants of these acids have been determined potentiometrically in 0.1 mol dm−3 sodium perchlorate solution at 25 °C. The distribution constants of these acids between the perchlorate media and chloroform and the dimerization constants in chloroform were also determined. The distribution constants of ortho-substituted benzoic acids seem to be larger than those of α-substituted phenylacetic acids with the same substituent. There is a trend that the higher the pKa, the larger the dimerization constant. The order of pKa is : o-aminobenzoic>o-methoxybenzoic>β-hydroxy-β-phenylpropanoic>α-hydroxyphenylacetic(mandelic)>α-methoxyphenylacetic>o-hydroxybenzoic acid and the sequence of the stability constants of their complexes for a given lanthanoid is also in a same order except for the mandelate. Mandelic acid forms more stable complexes with the heavier lanthanoid(III) while others are similar to each other regardless of the lanthanoid.