bluuebunny/crossref_metadata_2025 huggingface dataset:
Coincidence Mössbauer Spectroscopic Study of 57Co-Labelled CoSeO4 and CoSeO4·H2O
Authors: Watababe Yasuo , Nakada Masami , Endo Kazutoyo , Nakahara Hiromichi , Sano Hirotoshi
Published: July 2006

KX-Ray-gated emission Mössbauer spectra and time-resolved emission Mössbauer spectra of 57Co-labelled CoSeO4 and CoSeO4·H2O were measured at room temperature using a coincidence technique. No difference in the area intensity ratio of 57Fe(II) to the sum area intensity of 57Fe(II) and 57Fe(III) was observed for anhydrous CoSeO4 between the KX-ray-gated and non-gated emission spectra; a larger area intensity of 57Fe(II), however, was observed for the KX-ray-gated sectrum of CoSeO4·H2O than for the non-gated one. This difference is attributed to different local radiolytic effect of the deexcitation processes between KX-ray and Auger electron emission. The time-dependence in the area intensity ratio of 57Fe(II) to the sum area intensity of 57Fe(II) and 57Fe(III) was observed for CoSeO4·H2O. The relaxation process observed for CoSeO4·H2O by its time-resolved spectrum indicates that the radicals formed in the EC-decay oxidize 57Fe(II) on the time scale of the nuclear lifetime of the first excited state of 57Fe, and that a radical reaction plays an important role in determining the relaxation time.
Interfacial Phenomena in Ion-Association Extraction Kinetics of Iron(II) with 1,10-Phenanthrolines
Authors: Watarai Hitoshi , Sasaki Koh , Sasaki Naoko
Published: July 2006

The role of the interface in ion-association extraction kinetics of iron(II) with 1,10-phenanthroline(phen), 4,7-dimethyl-1,10-phenanthroline(DMP) or 4,7-diphenyl-1,10-phenanthroline(DPP) from sodium salt solutions was investigated by means of a high-speed stirring technique and a stopped-flow method. The initial extraction rates of the ion pairs were proportional to the first order of both iron(II) and the ligand concentrations in all cases studied; it was therefore suggested that the rate-controlling step is the formation of mono-complexes. From analyses using the adsorption constants and the distribution constants of the ligands and the formation-rate constants of the mono-complexes in the aqueous phase it was concluded that the location where the rate-controlling reaction takes place depends on the ligands: a bulk aqueous phase in phen, an interface in DPP, and both of a bulk aqueous phase and an interface in the case of DMP. The extraction rates were apparently reduced by an interfacial adsorption of the ion pairs, which was governed by the hydrophobicity of the ligands and the hydrophilicity of the counter anions.
New Column Packing Materials for Separation of Water-Soluble Vitamins by High-Performance Liquid Chromatography
Authors: Akiyama Shuzo , Nakashima Kenichiro , Shirakawa Nanako , Yamada Kyoko
Published: July 2006

Three types of high-performance liquid chromatographic column packing materials ((3-morpholinopropyl)-, [3-(1-piperazinyl)propyl]-, and (3-piperidinopropyl)silyl silica gels) were newly prepared and examined for their ability to separate water-soluble vitamins. Six vitamins (ascorbic acid, nicotinic acid, thiamine hydrochloride, pyridoxine hydrochloride, hydroxocobalamin acetate, and flavin adenine dinucleotide) in sample solutions could be completely separated within less than 12 min by UV detection on a column packed with morpholinopropylsilyl silica gel by using a phosphate buffer [0.1 M (1 M=1 moldm−3) H3PO4−0.1 M Na2HPO4 (pH 6.0) containing 10 mM tetrabutylammonium bromide] as an eluent. This efficient gel was successfully applied to vitamin analyses of commercially available healthful beverages. The other column packing materials also showed characteristic for specific water-soluble vitamin analysis. Typical separations are presented.
Nucleophilic Reaction upon Electron-Deficient Pyridone Derivatives. X.One-Pot Synthesis of 3-Nitropyridines by Ring Transformation of 1-Methyl-3,5-dinitro-2-pyridone with Ketones or Aldehydes in the Presence of Ammonia
Authors: Tohda Yasuo , Eiraku Miyuki , Nakagawa Takao , Usami Yumi , Ariga Masahiro , Kawashima Toshihide , Tani Keita , Watanabe Hiroko , Mori Yutaka
Published: July 2006

The reaction of 1-methyl-3,5-dinitro-2-pyridone (1a) with ketones or aldehydes in the presence of ammonia gave alkyl- and/or aryl-substituted 3-nitropyridines (6) in moderate to high yields. Enamines derived from the ketones gave better results than did the ketones themselves; on the other hand, those derived from the aldehydes gave no 6 at all. On the basis of deuterium-labeled experiments, a mechanism comprising competitive ring transformations of 1a is proposed.
Orbital Tilting and Hybridization Change. An Illustrational Molecular Orbital Approach to an Addition (CH2=CH2+HBr→CH3CH2Br) and an Elimination Reaction (CH3CH2Br/Base→CH2=CH2)
Authors: Ito Suketaka , Kakehi Akikazu
Published: July 2006

Configuration alteration and hybridization change in the addition of hydrogen bromide to ethylene and those in its reverse, E2-type reaction were illustrated in terms of orbital tilting on the basis of the concept of stabilizing and destabilizing second order orbital interactions. The predominancy of trans fashion in these reactions are also visualized qualitatively.
Asymmetric Cycloaddition of N-Metalated Azomethine Ylides with the Optically Active α,β-Unsaturated Esters Derived from α-Amino Acids
Authors: Kanemasa Shuji , Yamamoto Hidetoshi , Wada Eiji , Sakurai Tosio , Urushido Kunio
Published: July 2006

α,β-Unsaturated esters bearing a chiral oxazolidine or perhydropyrrolo[1,2-c]imidazole auxiliary at the β-position have been prepared and applied to the cycloadditions with N-metalated azomethine ylides derived from α-(benzylideneamino) esters. These reactions are found to proceed with an exclusively high diastereofacial selectivity to give 2,4-pyrrolidinedicarboxylates with four consecutive chiral centers after the removal of chiral auxiliary. Detailed stereochemistry in the transition state is discussed.
Fundamental Study on the Production of Ultrapure Water VIII. Removal of Leachables from Mixed-Bed Ion Exchange Resins
Authors: Agui Wataru , Takeuchi Masahito , Abe Masahiko , Ogino Keizo
Published: July 2006

A study was made concerning the removal of leachables released from mixed-bed ion exchange resins. The key concerns were to determine the optimum mixed ratio of strong acid cation exchange resins (SACERs) and strong base anion exchange resins (SBAERs), which give the minimum value of total organic carbon (TOC) released from the resin mixtures and to investigate the effect of synthetic carbonaceous adsorbents on the adsorption of the leachables. The leaching rates of the leachables from the resin mixtures were dependent on the mixed ratios of SACERs and SBAERs. The TOC value for the leachables showed a minimum for a SACER-to-SBAER volume ratio of 9:1, far different from the mixed ratio in ordinary water treatment. The release of leachables from resin mixtures was mainly due to SBAER. The carbonaceous adsorbent having a higher hydrophobic surface adsorbed the leachables well from the resin mixtures.
Preparation and Characterization of cis- and trans- [RhCl2(dmap)2]+ (dmap=1,3-bis(dimethylarsino)propane), and X-Ray Structure Analyses of These Complexes and trans-[CoCl2(dmap)2]+
Authors: Simonsen Kim , Hamada Masatoshi , Suzuki Nahomi , Kojima Masaaki , Ohba Shigeru , Galsbøl Frode , Saito Yoshihiko , Fujita Junnosuke
Published: July 2006

The cis- and trans- [RhCl2(dmap)2]+ (dmap=1,3-bis(dimethylarsino)propane) complexes were prepared by reaction of RhCl3·3H2O with dmap, and the molecular structures of these complexes were determined by the single crystal X-ray diffraction method. Crystal data and final R values are: trans-[RhCl2(dmap)2]ClO4 (1), monoclinic, Cc, a=20.018(4), b=10.229(1), c=12.972(2) Å, β=99.98(2)°, V=2616(1) Å3, Z=4, R=0.034 for 1298 observed unique reflections. cis-[RhCl2(dmap)2]PF6 (2a), orthorhombic, Pca21, a=14.699(2), b=9.381(2), c=19.640(9) Å, V=2704(1) Å3, Z=4, R=0.086 for 1284 reflections. cis-[RhCl2(dmap)2]CF3SO3 (2b), orthorhombic, Pca21, a=14.700(3), b=9.381(4), c=19.644(8) Å, V=2709(2) Å3, Z=4, R=0.088 for 1094 reflections. The Rh–As distances in the linear As–Rh–As groups are 2.442(4)–2.454(4) Å (av 2.446(4) Å) for (1), 2.345(4) and 2.484(6) (av 2.415(6) Å) for (2a), and 2.389(10) and 2.441(10) Å (av 2.415(10) Å) for (2b), while those in the linear As–Rh–Cl groups are 2.385(3) and 2.370(4) Å (av 2.378(4) Å) for (2a), and 2.387(4) and 2.367(5) Å (av 2.377(5) Å) for (2b). The molecular structure of trans-[CoCl2(dmap)2]Clo4 (3) was also determined by the X-ray method. Crystal data and the final R value are: orthorhombic, Pccm, a=8.018(2), b=8.428(1), c=18.716(3) Å, V=1265 Å3, Z=2, R=0.095 for 1072 reflections. A series of trans-[RhX2(dmap)2]+ (X=Cl, Br, I) were prepared and their absorption spectra were compared with one another and with those of related complexes.
Mercury-Photosensitized Decomposition of 2-Azetidinone and 4,4-Dimethyl-2-azetidinone
Authors: Yamamoto Shunzo , Kanetsuki Akihide , Sueishi Yoshimi , Nishimura Norio
Published: July 2006

The mercury-photosensitized decompositions of 2-azetidinone(AZ) and 4,4-dimethyl-2-azetidinone(DMAZ) have been studied at 453 and 423 K and at pressures from 750 to 18000 Pa and from 640 to 5000 Pa, respectively. The major products from AZ were carbon monoxide and ethylene, while ammonia was a minor product. The yields of carbon monoxide and ethylene increased linearly with increasing reaction time and light intensity; they were independent of the AZ pressure. These results suggest that carbon monoxide and ethylene are the primary products. The major products from DMAZ were carbon monoxide, isobutene, and 2,2-dimethylaziridine; ethane, isobutane, and propylene were the minor products. The yields of carbon monoxide, isobutene, and dimethylaziridine increased linearly with increasing reaction time and light intensity at 3800 Pa, showing that these products are the primary ones. The formation of minor products was not linear with time. The quantum yields of carbon monoxide and isobutene were independent of the DMAZ pressure, while the relative yield of dimethylaziridine to that of carbon monoxide increased and those of the minor products decreased with an increase in pressure. Plausible mechanisms were proposed.
Gamma Radiolysis of Cu(II) Complex of Metronidazole
Authors: Mandal P C , Bardhan D K , Bhattacharyya S N
Published: July 2006

Aqueous solutions of Cu(II) Metronidazole (CuIIM) at neutral pH were irradiated with 60Co γ-rays under different conditions of radiolysis. The radiolytic formation of HNO2 and CuI was followed. The radiolytic yields of chromophore loss of CuIIM were also determined under different conditions. The OH radicals attack the metal complex to give the OH adducts of the ligand at C2, C4, and C5 either directly or through the formation of Cu(III) species. The C5–OH adduct, however, undergoes oxidative denitration and as a result the metal complex is decomposed. The OH adducts also undergo electron transfer to CuII ion to give reduced complex. No denitration was observed due to the reaction of eeq− with the metal complex. On the other hand, the nitro group of the ligand in the complex undergoes successive 4-electron reduction to give hydroxylamino derivative. From the competition kinetics using t-butyl alcohol as the scavenger of OH in N2O saturated solution of the metal complex, the rate constant for the reaction of OH with complex was evaluated to be ca. 2.1×109 dm3mol−1s−1 which is of the same order as that observed in the case of free metronidazole.
Determination of the Configuration of Diastereoisomers of 2-Alkyl-3-hydroxybutanoates with Gas Chromatography
Authors: Nakamura Kaoru , Miyai Takehiko , Nagar Ashish , Babu B Ramesh , Ando Takashi , Ohno Atsuyoshi
Published: July 2006

Diastereoiscomers of 2-alkyl-3-hydroxybutanoates are separated by gas chromatography. The threo (anti)-isomers have shorter retention times than those of the corresponding erythro (syn)-isomers.
On Tautomerism and Self-Association of 2-Pyridinol/2-Pyridone System
Authors: Millefiori Salvatore , Millefiori Arcangelo
Published: July 2006

The semiempirical “Effective Pair Correlation Energy” method of Sinanoglu et al. has been employed to investigate the role of the electron correlation energy in the cis-trans, protomeric and dimerization equilibria in the 2-pyridinol (HP2)/2-pyridone (P2) system. CNDO/2 wave functions were used throughly. Preliminary calculations on test cases formic acid, water dimer, and ammonia-water dimer gave acceptable figures in comparison with more accurate literature data. The results show that in HP2 the N–C–O–H cis isomer is more stable than the trans isomer by 2.7 kJ mol−1. Correlation energy favors the trans isomer by 2.9 kJ mol−1 and the keto P2 form over the HP2 form by 11.3 kJ mol−1, in qualitative agreement with results of ab initio calculations. The correlation energy term is stabilizing for the associative process of both tautomers. The numerical data are greatly dependent on the intermolecular equilibrium distance, the best results being obtained at experimental equilibrium distances. (P2)2 dimer is correctly predict to be more stable than (HP2)2 dimer. The correlation energy contribution amounts to 22 and 12.4 kJ mol−1 per hydrogen bond in (HP2)2 and (P2)2, respectively.
Effect of Fe(III) Ions on the γ-Radiolysis of Thymine
Authors: Bhattacharyya S N , Mandal P C , Chakrabarti S
Published: July 2006

Aqueous solutions of thymine (T) in the presence of Fe(III) were irradiated under deaerated conditions at pH ≈2. The products of radiolysis were separated by two dimensional thin-layer chromatography. In the absence of any metal ion, the G(-T) is 2.6 but when Fe(III) is present during radiolysis, the G(-T) increases significantly and reaches a limiting value of 3.2. The yields of the hydroxylated products of thymine also increase in the presence of Fe(III). The results were explained by a mechanism which involves the interactions of Fe(III) with the transient adducts of thymine.
Conformation of 1-Methyl-3,4-benzo-7-thia-2-azabicyclo[3.3.1]non-3-ene 7-Oxide
Authors: Hatano Keiichiro , Takeuchi Isao , Hamada Yoshiki , Yashiro Tamotsu , Kurono Yukihisa
Published: July 2006

The crystal and molecular structures of 1-methyl-3,4-benzo-7-thia-2-azabicyclo[3.3.1]non-3-ene 7-oxide have been determined on the basis of three-dimensional X-ray data. The six-membered thiane ring in this novel tricyclic system has been elucidated to adopt a chair-type conformation with an axial-axial aza-phenyl substituent and an equatorial sulfinyl group. The conformation in the solid state was consistent with that previously proposed by molecular mechanics calculations.
Hydrogen Isotope Equilibration of HD on MgO below Room Temperature
Authors: Ito Tomoyasu , Tominaga Nobuyuki , Tashiro Toshihiko , Toi Keio , Ikemoto Isao , Kobayashi Hisayoshi
Published: July 2006

MgO pretreated at ca. 823 K in vacuo showed the highest catalytic activity for an isotope equilibration reaction, 2HD=H2+D2, at 195 K. This reaction proceeds through an interaction of dissociatively adsorbed hydrogen on a pair site consisting of lowly coordinated ions, MgLC2+–OLC’2− residual OH− at the nearest lattice position.
A New Syntheic Route to Hexachloromolybdate(III). An X-Ray Structure of (NH4)3[MoCl6]
Authors: Shibahara Takashi , Yamasaki Mikio
Published: July 2006

Ammonium hexachloromolydbate(III) (NH4)3[MoCl6] was obtained by tin metal reduction of ammonium molybdate in high yield (80%). The X-ray structure was determined. Crystal data: tetragonal system, space group P42/m, a=8.822(3) Å, c=7.271(2) Å, V=565.9(3) Å3, Z=2, R(Rw)=3.35(5.47). Two independent Mo–Cl distances (2.439(2) and 2.451(1) Å) exist.
Effect of Trace Water in Chloroform on Coordination Mode of the Tetraazamacrocyclic Complex Comprised of Nickel(II) Bromide and 7R(S),14S(R)-5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane
Authors: Mochizuki Katsura , Suwabe Masaaki , Ito Tasuku
Published: July 2006

Trans-[NiBr2L](L= the titled macrocyclic ligand) dissolves in freshly purified chloroform containing a very small amount of water to give an equilibrium mixture between the low-spin four coordinate and the high-spin six coordinate complexes. High temperature favors the high-spin form. This is opposite to the well-known behavior of equilibria in H2O between low-spin four coordinate and high-spin six coordinate nickel(II) complexes with similar tetraaza macrocyclic ligands. Trace water in chloroform facilitates the formation of the low-spin species.
Halogenation Using Quaternary Ammonium Polyhalides XXVII. Chloroiodination of Alkenes with Benzyltrimethyl ammonium Dichloroiodate
Authors: Kajigaeshi Shoji , Moriwaki Masayuki , Fujisaki Shizuo , Kakinami Takaaki , Okamoto Tsuyoshi
Published: July 2006

The reaction of alkenes with benzyltrimethylammonium dichloroiodate in dichloromethane gave the chloro iodo adducts in anti-stereospecific and regioselective manner; in methanol these adducts were obtained along with methanol-incorporated products.
Convenient Alkylation of 6,7-Dihydro-7-5H-pyrrolo[3,4-b]pyridin-5-ones in a Phase Transfer System. Synthesis of Novel Cyclic Nicotinamide Analogs
Authors: Goto Takehiko , Endo Mikihiro , Saito Minoru , Sato Ryu
Published: July 2006

The title reaction is readily achieved with alkyl halides in the presence of sodium hydroxide and a phase transfer catalyst to afford 7-alkylated derivatives in good yields. The present reaction involving intramolecular double-alkylation at C-7 and N-6 with dihalides leads to novel fused heterocyclic systems.
Photosolvolysis of 2-Alkoxy-2-phenyl-1,3-dithiolane
Authors: Okuyama Tadashi , Haga Naoki , Fueno Takayuki
Published: July 2006

2-Methoxy- and 2-ethoxy-2-phenyl-1,3-dithiolane are hydrolyzed to the thioester in neutral aqueous solution by irradiation with a low-pressure Hg lamp. Irradiation of a solution of the alkoxy dithiolanes in alcohol induces easily the alcohol exchange.
Statistical Thermodynamic Study of Liquid Organic Compounds
Authors: Kawai Satoshi , Arakawa Kiyoshi
Published: July 2006

A statistical thermodynamic study of liquid organic compounds has been worked out on the basis of a liquid model: a liquid is regarded as an assembly of particles immersed in a uniform background potential resulting from the attractive forces between molecules. In the model the equation of state is expressed as a sum of the term derived from the analytical solution of the Percus–Yevick equation and that from the background potential. Calculations of thermodynamic functions for five liquids (benzene, carbon tetrachloride, toluene, chloroform, cyclohexane) have been performed. The results show the effectiveness and reasonableness of the theory with the evidence of coincidence of calculated values and observed ones.
Detection of Odorous Substances by Using a Lipid-Coated Quartz-Crystal Microbalance in the Gas Phase
Authors: Okahata Yoshio , Shimizu Osamu , Ebato Hiroshi
Published: July 2006

The adsorption behaviors and partition coefficients of various odorants and perfumes in a lipid matrix were measured in the gas phase using a dimethyldioctadecylammonium poly(styrene-4-sulfonate) multibilayer film-coated quartz-crystal microbalance (QCM), the resonance frequency of which changes linearly with increasing the absorption amount on the lipid matrix on the QCM. A good correlation was observed between the partition coefficients of various odorous substances or perfumes in the lipid matrix and the odor intensity in humans obtained by smelling tests for the same compounds. A similar relation was observed regarding the absorption behavior to an olfactory epithelium-coated QCM in the gas phase. Odorant having a strong intensity showed higher adsorption in the lipid matrix on the QCM. The partition coefficients increased in the solid state of the lipid matrix, compared with the fluid-liquid crystalline state. As compared with absorption experiments in the aqueous phase, the high partition coefficients of odorants in the lipid matrix and the good correlation between the partition coeffcients and the odor intensity in humans were observed in the gas phase.
Structure of Reaction Products of 5-Nitrosotropolone and Arylamine
Authors: Asao Toyonobu , Imajo Seiichi , Nozoe Tetsuo
Published: July 2006

The structures of abnormal reaction products (1:1 and 1:2) between 5-nitrosotropolone and arylamine are elucidated. The reaction of 5-nitrosotropolone with arylamine (e.g., aniline and p-toluidine) affords initially a bicyclic addition product, having 8-azabicyclo[3.2.1]octane system which could be formed by the attack of the amine on 4- and 1-positions of the tropolone ring. The adduct contains two isomers having syn and anti configuration with respect to the hydroxyimino group. These adducts easily isomerized under alkaline conditions to form lactams having the 6-azabicyclo[3.2.1]octane system, which may have been resulted from skeletal rearrangement of a seven-membered ring to a six-membered one. The former adducts, the 8-azabicyclo[3.2.1]octane system, further react with another mole of arylamine to give 1:2 products containing a lactam moiety via similar skeletal rearrangement.
Double Silylation of 1,4-Bis(trimethylsilyl)butadiyne with Disilanes Using a Palladium Catalyst
Authors: Kusumoto Tetsuo , Hiyama Tamejiro
Published: July 2006

Reaction of 1,4-bis(trimethylsilyl)butadiyne with polychlorodisilanes Si2ClxMe6−x in the presence of a palladium catalyst gives, after methylation, 1,1,4,4-tetrakis(trimethylsilyl)butatriene and/or 1,1,2,4-tetrakis(trimethylsilyl)-1-buten-3-yne selectively. Hydrogenation, hydrosilylation, and oxidation of the obtained butatriene were found to take place at C(1)=C(2) double bond exclusively. The regioselectivity is ascribed to the geminally substituted silyl groups which sterically direct the attack of electrophile and stabilize postulated radical intermediates.
Tertiary Amine-Catalyzed Acyl Group Exchange Reaction of N,O-Diacyl-o-aminophenols. Its Mechanism and Factors Determining the Relative Stability of Acyl Exchanged Isomer Pairs
Authors: Sakurai Tadamitsu , Kojima Shuichi , Inoue Hiroyasu
Published: July 2006

Acyl substituent effects on the equilibrium and rate constants for the acyl group exchange reactions of various N,O-diacyl-o-aminophenols have been investigated in solvents with different polarities. It was found that the relative stability of acyl exchanged isomer pairs is determined solely by the inductive effect of acyl groups, provided that the steric hindrance of acyl substituents bonded to amide nitrogen affects the stability to the same extent. The importance of steric hindrance exerted by a bulky acyl group in determining the relative stability was demonstrated by analyzing the correlation between the standard free energy change (ΔG°) and pKa, which were used as the measure of the relative stability of isomer pairs and of the electron-withdrawing ability of acyl groups, respectively. On the other hand, the logarithms of catalytic rate constants for the acyl migration reactions were correlated well to the pKa values. In addition to this finding, a large negative value of activation entropy ΔS\eweq=−160 J K−1 mol−1) and the Brønsted coefficient β of 0.65 for the reaction of N,O-(acetyl)-(1-naphthoyl) pair of N,O-diacyl-o-aminophenol provide a definitive evidence for the rate-determining proton transfer from this derivative to amine catalyst in the transition state.
1H NMR Study of Conformation of Formyl-l-phenylalanyl-6-deoxy-6-amino-cyclomaltoheptaose That Has Excellent Ability of Chiral Recognition
Authors: Saka Wataru , Yamamoto Yasuhiko , Inoue Yoshio , Chûjô Riichirô , Takahashi Keiko , Hattori Kenjiro
Published: July 2006

N-(N-Formyl-l-phenylalanyl)-6-deoxy-6-aminocyclomaltoheptaose (f-l-Phe-β-CD) is one of CD derivatives with excellent ability of chiral recognition. In order to make clear the mechanism of chiral recognition, the conformation of free f-l-Phe-β-CD has been studied by using 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. From the measurement of 1H homonuclear Overhauser enhancement on the rotating frame, it is concluded that f-l-Phe- residue of the f-l-Phe-β-CD is inserted into its cavity from the upside of primary hydroxyl groups of the macrocyclic ring. Analysis of 1H and 13C spectra of f-l-Phe-β-CD and model compounds of f-l-Phe- residue also support this conclusion. The macrocyclic ring is found to be distorted.
Study of Polarographic Anodic Wave Controlled by the Rate of Precipitation Reaction in the Presence of Citrate Ion
Authors: Kikuchi Kenji , Murayama Teisuke
Published: July 2006

The anodic wave of mercury observed in the presence of citrate ions has been studied by a numerical method previously proposed by us. The anodic current increases with an increase of concentration of citrate ion. The anodic wave does not show any diffusion current plateau. The logarithm of the anodic current is plotted against the electrode potential, giving a straight line with a slope of 53–55 mV/unit. With the numerical method, it becomes clear that the anodic wave is controlled by the rate of precipitation, which is too low to attain equilibrium within a drop life and is independent of the surface area of the precipitates.
Formation of CH3Si8O197− Cubic Octameric Anion in (2-Hydroxyethyl)trimethylammonium Silicate Aqueous Solutions Containing Hydrolysis Products of Methyltriethoxysilane
Authors: Hasegawa Isao , Sakka Sumio
Published: July 2006

CH3Si8O197−, in which a Si(O−)4 unit in the cubic octameric silicate anion (Si8O208−) is displaced by a CH3Si(O−)3 unit, has been formed in aqueous solutions of mixture of hydrolysis and polycondensation products of tetraethoxysilane and methyltriethoxysilane under the presence of (2-hydroxyethyl)trimethylammonium ions. The ammonium ions have not had any significant effects on polymerization of hydrolysis products of methyltriethoxysilane in aqueous solutions and the polymerization has taken place randomly to form a widespread distribution of the species with various structures. The hydrolysis product, however, has taken part in the formation process of the cubic octameric silicate anion with the aid of the organic ammonium cations, resulting in the formation of CH3Si8O197−.
Synthesis and Reaction of Diaminosulfoxonium Salts
Authors: Okuma Kentaro , Higuchi Naotsugu , Kaji Shinji , Takeuchi Hiroshi , Ohta Hiroshi , Matsuyama Haruo , Kamigata Nobumasa , Kobayashi Michio
Published: July 2006

Diaminosulfoxonium salts were prepared by alkylation of sulfonimidamides. Their physical properties were described. Their reaction with bases gave the corresponding ylides and sulfonimidamides. The intramolecular rearrangement of the ylides led to ortho substitution via intermediate cyclohexadienimines. Hydrogen transfer, accompanying rearomatization and the subsequent action of bases gave dihydro-2,1-benzisothiazole derivatives. These ylides were also found to react with aldehydes to afford epoxides in moderate yields.
Photocarboxylation of Naphthalene in the Presence of Carbon Dioxide and an Electron Donor
Authors: Tagaya Hideyuki , Onuki Masatoshi , Tomioka Yoshiki , Wada Yoshinori , Karasu Masa , Chiba Koji
Published: July 2006

Naphthalene was carboxylated to naphthoic acids by the irradiation of naphthalene and a donor in the presence of carbon dioxide. The UV irradiation through Pyrex caused reactions of naphthalene, itself, giving a naphthalene dimer etc. Such undesirable reactions were partly depressed by using a CuSO4 filter solution; the selectivities of naphthoic acids and dihydronaphthalenecarboxylic acid increased from 2.2–9.8 to 12.2–23.0%. To avoid any direct irradiation to naphthalene and naphthoic acids was critical. Their high selectivities, up to 67%, were obtained upon visible light irradiation by using phenazine as a sensitizer. More than 90% of the naphthoic acids was 1-naphthoic acid, which was confirmed by GC and ms.
What Does Hückel MO Method Calculate?—On the Relationship between HMO Energy and the Kinetic Energy of π Electrons
Authors: Ichikawa Hiroshi , Sameshima Keiichiro
Published: July 2006

The Hückel MO energies of linear polyenes (1–9 in Fig. 1)were compared with each energy component of the Hartree–Fock total energy. It was concluded that the Hückel MO energy is closely proportional to the kinetic energy of the π electrons between the 2p AOs. This linear relation held in various types of these (1–43) polyenes. It was also shown that the ratio of the π kinetic energy to the total kinetic energy is almost constant. Thus, we may understand with the help of the virial theorem why the Hückel MO energy represents the total energy. We also give a physical background to the theories of aromaticity/antiaromaticity.
119Sn-Emission Mössbauer Studies on 119mTe and 119Sb in S, Se, and Te
Authors: Ambe Shizuko , Ambe Fumitoshi
Published: July 2006

The valence states of 119Sn produced by the EC decay of diluted 119Sb and 119mTe chemically doped in S, Se, and Te were studied by emission Mössbauer spectroscopy. The Mössbauer spectra of S(119mTe) and Se(119mTe) consist of peaks ascribable to Sn(IV) and to Sn(II) surrounded by S or Se, respectively. The Mössbauer spectra of Te(119Sb) samples show that, though a greater part of the 119Sb atoms are dispersed in the Te matrix after coprecipitation and sublimation, upon slow recrystallization after fusion most of the dispersed 119Sb atoms aggregate to form microcrystals of 119Sb2Te3.
Behavior of I2 and I3− Molecular Units Near the Crystal Surface of CsI and Related Polyiodides. Raman-Spectroscopic Studies
Authors: Odagi Kazumasa , Nakayama Hideyuki , Ishii Kikujiro
Published: July 2006

Raman spectra of CsI3 and Cs2I8 crystals were measured for the samples whose structures were carefully examined. The surface of Cs2I8 samples was found to turn into CsI3 when they were kept in air. The heating effect of laser irradiation was shown to change the spectra of Cs2I8 samples to those of CsI3. These results imply that diffusion of iodine molecules occurs in polyiodide crystals. Then, we monitored the reaction of CsI crystals with iodine vapor, and found that iodine makes the layers of CsI3 and CS2I8 on the surface of CsI crystals. It was also found that nearly free I3− ions are generated near the surface of samples during both the thermal decomposition of Cs2I8 and the reaction of CsI with iodine vapor.
Hydrogenation of Unsaturated Carboxylic Acid Catalyzed by Platinum–Silica Coupled with Alkylsilyl Chloride
Authors: Kuno Hideyuki , Takahashi Kyoko , Shibagaki Makoto , Matsushita Hajime
Published: July 2006

Platinum–silica catalysts coupled with alkylsilyl chloride were prepared for the regioselective hydrogenation of unsaturated compounds. These catalysts were stable in polar solvents. It was found that the carbon–carbon double bond far from a hydrophilic site was more rapidly hydrogenated in this catalyst system.
1H and 19F NMR Relaxations of Electroconducting Polypyrrole and Polythiophene Trifluoromethanesulfonates
Authors: Mizuno Motohiro , Asaji Tetsuo , Nakamura Daiyu , Inoue Michiko B , Inoue Motomichi
Published: July 2006

The NMR relaxation time T1 of 1H and that of 19F were determined for polypyrrole and polythiophene doped with trifluoromethanesulfonate (triflate) or perchlorate ions. The 1H T1 is governed by the paramagnetism of the polymer chains. The 19F T1 of the triflate ions is explained by the combined effect of the F–F dipolar interaction and the electron–nucleus coupling. The activation energy for CF3 reorientation about the C3 axis was 7.5 kJ mol−1 for polypyrrole triflate and 15 kJ mol−1 for the corresponding polythiophene.
Temperature Dependence of the Fluorescence Intensity of 1-Benzyloxy-2-pyridone and Related Compounds
Authors: Sakurai Tadamitsu , Yoshikawa Kazuhiro , Inoue Hiroyasu
Published: July 2006

A quantitative analysis of the temperature dependence of fluorescence intensity of the title compounds in saturated hydrocarbon solvents has revealed that the relevant thermally-activated radiationless process from singlet manifold involves a rotation about the N–O bond in these compounds.
Synthesis and Catalytic Capability of Zeolite-Encapsulated Iron and Manganese Tetramethylporphine Complexes
Authors: Nakamura Makoto , Tatsumi Takashi , Tominaga Hiro-o
Published: July 2006

Iron and manganese tetramethylporphine (TMP) complexes were synthesized within the cages in NaY zeolite. The ligation of porphine to the metals enhanced the capability of ion-exchanged zeolite to oxidize saturated hydrocarbons with hydrogen peroxide.
1H NMR Characterization of the Hydrogen-Bond Network in the Water Complex of Resorcinol-Dodecanal Cyclotetramer
Authors: Tanaka Yasutaka , Aoyama Yasuhiro
Published: July 2006

1H NMR spectroscopy on the water complex of resorcinol-dodecanal cyclotetramer indicates that a bound water molecule and a pair of OH groups on adjacent benzene rings of the macrocycle are strongly NOE correlated, but the proton exchange in the resulting hydrogen-bond network is very slow.
Photoreactions of 2-(Dialkylamino)ethyl Esters of γ-Oxo Acids via Remote Hydrogen Transfer: Influence of the Stability and Conformational Flexibility of the Biradical Intermediate on Its Chemical Behavior
Authors: Hasegawa Tadashi , Mukai Keiko , Mizukoshi Kimiko , Yoshioka Michikazu
Published: July 2006

2-(Dibenzylamino)ethyl 4-phenyl-3-oxobutanoate underwent photocyclization via remote hydrogen migration to give 9-membered azalactones, while 2-(dimethylamino)ethyl 4-phenyl-3-oxobutanoate gave only a polymer. Irradiation of 2-(N-methylbenzylamino)ethyl 4-phenyl-3-oxobutanoate gave azalactones via a benzylic hydrogen transfer. No azalactones via methyl hydrogen migration could be detected. The stability and conformational flexibility of biradical intermediates are important factors in the present photocyclization.
Effect of the Chain Length of N-Alkyl-β-alanine on Their Copper Complex Formation in Aqueous Solution
Authors: Nakamura Akio , Koshinuma Masakatsu , Tajima Kazuo
Published: July 2006

The effects of the chain length of N-alkyl-β-alanine (NAA) (the number of carbon atoms in the alkyl chains; n=0, 2, 4, 6, 8, 10, 12) on the copper(II) complex formation and its properties were investigated. The complex formation constants for two-step reactions were determined by potentiometry using the selective electrodes of copper(II) and hydrogen ions. The values of the complex formation constants decreased with increasing chain length of the alkyl substituents, and became constant for the substituents longer than the butyl group. These results could be explained in terms of a steric hindrance effect of the N-alkyl substituents on these coordination reactions. Each logarithmic function of the solubility and of the solubility product of the 1(Cu):2(NAA)-complexes was found to be expressed, respectively, as a linear function of the number of carbon atoms in the alkyl group. From these data, the standard free energies of the formation and the precipitation of the 1:2-complexes from these constituent ions have been estimated, and a standard free energy diagram was constructed for 1:2-complex formation. It was concluded that the hydrophobic interaction is a driving force which promotes crystalline complex formation from the constituent ions.
Selective Separation of Structurally or Electronically Similar Ethers with MAD
Authors: Maruoka Keiji , Nagahara Sigeru , Yamamoto Hisashi
Published: July 2006

Selective separation of the less hindered or electronically more labile of two different ethers has been accomplished with exceptionally bulky, Lewis acidic MAD by the yield of precipitates as selective Lewis acid-base complexes.
Selective Skeletal Rearrangement of Tricyclo[5.4.0.01,5]undecanes to Tricyclo[5.3.1.01,5]- and [5.4.0.03,8]undecanes
Authors: Kakiuchi Kiyomi , Kumanoya Shuichi , Kobiro Kazuya , Tobe Yoshito , Odaira Yoshinobu
Published: July 2006

An acid-catalyzed rearrangement of tricyclo[5.4.0.01,5]undecan-ll-one gave tricyclo[5.3.1.01,5]undecan-11-one in a nonnucleophilic media and tricyclo[5.4.0.03,8]undecane-7, 8-diol in the presence of a nucleophile, respectively. Tricyclo[5.4.0.01,5]undecan-11-ols also rearranged to tricyclo[5.4.0.03,8]undecan-7-ol. A reductive rearrangement with a hydride transfer of the alcohol gave only tricyclo[5.4.0.03,8]undecane.
Convenient Synthesis of β-Silyl Ketones from β-Stannyl Enol Silyl Ethers via a [1,4] Anionic Rearrangement of Silicon
Authors: Nakahira Hiroyuki , Ryu Ilhyong , Ogawa Akiya , Kambe Nobuaki , Sonoda Noboru
Published: July 2006

The transmetalation (Sn to Li) and [1,4] anionic rearrangement of β-stannyl enol silyl ethers have been achieved, providing a convenient method for synthesis of β-silyl ketones.
Comparison between Intra- and Intermolecular Photoinduced Electron Transfer Reactions of Micelle-Solubilized Substances
Authors: Suga Kosaku , Fujita Shigeru , Yamada Hiroshi , Fujihira Masamichi
Published: July 2006

The rate constants of intramolecular photoinduced electron-transfer reactions of a linked pyrene–viologen molecule A and a linked pyrene–ferrocene molecule B solubilized in micellar solutions of a hexadecyltrimethylammonium chloride were determined to be 9×108 and 4×108 s−1 respectively, from the stationary fluorescence intensity. However, the observed fluorescence decay curve of A suggests that a large fraction of the molecules have conformations for which the distances between two functional moieties are sufficiently small to permit direct electron transfer. The quasi-first-order rate constants of the intermolecular photoinduced electron-transfer reactions between 1-hexylpyrene (HPy) and dodecylviologen (DDV), and between HPy and butylferrocene (BFc) solubilized in a micellar solution, were also determined to be 9×106 and 2×107 s−1 respectively, from the fluorescence decay curves. It is shown that the rate constants of the intermolecular photoinduced electron-transfer reaction in micelles are determined by the diffusion of the reactants in a micelle. On the other hand, it is suggested that the rate constants of the intramolecular electron-transfer reactions are determined by the molecular conformations of the linked compounds in micelles.
Hydration of Oligosaccharides
Authors: Uedaira Hisashi , Ishimura Miyuki , Tsuda Sakae , Uedaira Hatsuho
Published: July 2006

The spin-lattice relaxation times, T1, of H217O have been measured for aqueous solutions of 2 di-, 2 trisaccharides, α-, and γ-c clodextrins as a function of the concentration at 25°C. The dynamic hydration numbers, nDHN, for 17 sugars including monosaccharides were expressed by the linear relation of the mean number of the equatorial OH groups. The second virial coefficients showed a good correlation with nDHN. Though the rotational correlation times, τch, of water molecules in the cosphere of sugar molecules increased with increasing the number of equatorial OH groups for monosaccharides, those for trisaccharides and cyclodextrins showed almost constant values. The relation between the values of the limiting diffusion coefficients and nDHN for sugars was found to be expressed by two lines with a large negative slope for mono- and di- saccharides, and a small negative slope for trisaccharides and cyclodextrins.
Synthesis and Chromogenic Properties of Some Water-Soluble 5-Nitro-2-Pyridylhydrazones
Authors: Kohata Katsunori , Kawamonzen Yoshiaki , Odashima Tsugikatsu , Ishii Hajime
Published: July 2006

Four new water-soluble hydrazones, α-(5-nitro-2-pyridyl)hydrazono-α-(2-quinolyl)-3-toluenesulfonic acid, α-(5-nitro-2-pyridyl)hydrazono-α-(2-thiazolyl)-3-toluenesulfonic acid, α-(2-benzothiazolyl)-α-(5-nitro-2-pyridyl)hydrazono-3-toluenesulfonic acid, and α-(2-benzimidazolyl)-α-(5-nitro-2-pyridyl)hydrazono-3-toluenesulfonic acid, were synthesized. Their proton dissociation constants were determined spectrophotometrically. The chromogenic properties of the synthesized hydrazones and their reactions with metal ions were investigated spectrophotometrically in detail. The results revealed that the synthesized hydrazones react with various metal ions including transition metal ions, especially with cadmium(II), nickel(II), and zinc(II) to form stable colored complexes with very large apparent molar absorptivities, so that they were found to be all very useful as highly sensitive spectrophotometric reagents.
The Solubility and Cyclodextrin Complexations of Fluorene, Fluoranthene, and Pyrene in Aqueous Medium
Authors: Wu Yue , Ishibashi Kazunari , Deguchi Toshio , Sanemasa Isao
Published: July 2006

The vapor saturation method was applied to prepare aqueous solutions saturated with a volatile solid solute such as fluorene, fluoranthene, or pyrene. Henry’s law was found to hold for their aqueous solubility, and sublimation enthalpy was evaluated for each solid solute. Complex formation constants with cyclodextrins at 25°C have been determined by the vapor saturation method. The applicability and limitation of the method are discussed.
The Anion Radicals of Pheophytin a and its Derivatives Studied by Means of CIDNP Technique
Authors: Maruyama Kazuhiro , Yamada Hiroko , Osuka Atsuhiro
Published: July 2006

We applied the Chemically Induced Dynamic Nuclear Polarization (CIDNP) technique to the photochemical reaction of pheophytin a (P1) and 4-methoxyphenol (1) in benzene-d6. The observed CIDNP effects were explained in terms of reversible electron-transfer reactions from 1 to 3(P1)* and from (P1)\ewdot to (1)\underset.+. The polarized signals of P1 were induced from the in-cage recombination of the triplet radical ion pair.
Excimer Fluorescence of Pyrene in Sol–Gel Silica
Authors: Matsui Kazunori , Usuki Naomi
Published: July 2006

The fluorescence and excitation spectra of pyrene at high concentrations were studied along the sol to xerogel stages of the sol–gel silica formed by the acidic hydrolysis of tetraethyl orthosilicate. The monomer and excimer fluorescence of pyrene were observed in the reaction system. Their relative intensities revealed that complex changes occurred that depended on the reaction time and the excitation wavelengths. The environmental polarity of the probe molecules also changed as shown by the fluorescence vibronic structure. The excitation spectrum of the excimer fluorescence in some stages was red shifted in comparison with that of the monomer fluorescence, indicating the existence of bimolecular ground-state pyrene associations. The mechanism by which pyrene molecules are trapped in the silica network is discussed on the basis of the results.
Tentative Reaction Network for Bromate–Bromide–Ferroin System and Simulation of Behavior of the System under Batch Reactor and Continuous-Flow Stirred Tank Reactor Conditions
Authors: Sasaki Yoshihiro
Published: July 2006

One tentative reaction network for the bromate–bromide–tris(1,10-phenanthroline)iron(II) (ferroin) system in an acidic medium was examined by means of a simulation method, which involved the Field–Körös–Noyes scheme, the reduction of HBrO2 and HOBr by ferroin via two-electron transfer processes and the reactions of Fe(phen)22+ with BrO3−, HBrO2, HOBr, and BrO2·. The network successfully reproduced the behavior of the system in a batch reactor. The behavior of the system in a continuous-flow stirred tank reactor (CSTR) was simulated under two CSTR conditions: 1) Bromide flowed into the CSTR, and 2) bromide did not flow into the CSTR. Under the former condition, the system exhibited bistability and sustained oscillations. The calculated oscillations were of small amplitude and high frequency. Under the latter condition, the system exhibited bistability.
Catalytic Hydrogasification of a Carbon Material with Dodecacarbonyltriiron(0) and Iron(iii) Nitrate: Effects on Surface Area, Pore Structure, and Hydrogen Adsorption
Authors: Arai Masahiko , Nishiyama Yoshiyuki
Published: July 2006

The catalysis of adsorbed dodecacarbonyltriiron(0) was used to develop the pore structure of a carbon through its partial gasification with hydrogen. The catalytic gasification at 500 °C increased the volumes of pores, in particular those of 3–5 nm in diameter. In contrast, such an effect was not observed when iron(III) nitrate was used as a catalyst. The adsorbability of hydrogen on carbon-supported iron particles obtained after gasification was examined by temperature-programed desorption (TPD). The TPD spectrum of hydrogen, in particluar, at temperatures above 200 °C, for a cluster-derived sample differed from that for a nitrate-derived sample. In addition, the apparent activation energy for the desorption of hydrogen in a low-temperature peak at around 90 °C for the former sample was larger than that for the latter. Heat treatments caused the TPD characteristics of the cluster-derived sample to become very similar to those of the nitrate-derived sample.
Stereoselective Isomerization Reactions of the (Ethylenediamine-N,N′-diacetato)(ethylenediamine)cobalt(III) and (Ethylenediamine-N,N′-diacetato)(glycinato)cobalt(III) Complexes in a Basic Aqueous Solution
Authors: Kawaguchi Hiroshi , Uchiyama Naomi , Ama Tomoharu , Yasui Takaji
Published: July 2006

Isomerization reactions of the [Co(edda)(en)]+ and [Co(edda)(gly)] systems were studied in a basic aqueous solution. Λ(R)-β-[Co(edda)(en)]+ isomerized to the Λ(S,S)-α-isomer with an optical purity (o.p.) of ca. 45%. In the reactions of three isomers of [Co(edda)(gly)], Λ(R)-β-fac(O) isomerized to Λ(R)-β-mer(O) (o.p.: ca. 100%) and Λ(S,S)-α-mer(O) (o.p.: ca. 33%), Λ(R)-β-mer(O) to Λ(R)-β-fac(O) (o.p.: ca. 65%) and Λ(S,S)-α-mer(O) (o.p.: ca. 40%), and Λ(S,S)-α-mer(O) to Λ(R)-β-fac(O) (o.p.: ca. 50%) and Λ(R)-β-mer(O) (o.p.: ca. 60%). These results were explained on the basis of a Co–O bond-rupture mechanism.
Effects of Chloro Substituent on Solvent Extraction of Copper(II) with o-, m-, and p-Chlorobenzoic Acids
Authors: Yamada Hiromichi , Horikawa Shiho , Fujii Yukio , Mizuta Masateru
Published: July 2006

Through the solvent extraction of copper(II) with the three isomeric chlorobenzoic acids in 1-octanol, it has been shown that the entrance of chloro substituent into the three positions in the benzene ring of benzoic acid results in an individuality in the extraction behavior for copper(II). The dimeric copper(II) chlorobenzoates CU2A4 and Cu2A4(HA)2 were responsible for the extraction with m-chlorobenzoic acid together with the monomer CuA2, while only the monomeric species CuA2 was extracted with o- and p-chlorobenzoic acids. The entrance of chloro group into the ortho position in benzoic acid was found to result in a lowering of both the partition constants of o-chlorobenzoic acid itself and its copper(II) compound. That into the para position has led to a significant decrease in the solubilities of the para isomer and its copper(II) compound in both aqueous and octanol phases.
Transformation of α-Santonin into 7-Hydroxyeudesmanes
Authors: Nagano Hajime , Sugihara Hiroko , Harada Noriko , Fukuchi Natsuko , Yamada Keiko , Izawa Hiroko , Shiota Michio
Published: July 2006

Autoxidation of (11S)-12-hydroxy-7α-eudesmane-3,6-dione in the presence of p-toluenesulfonic acid gave 6,12-epoxy-11β-eudesma-4,6-dien-3-one, which was oxidized with m-chloroperoxybenzoic acid to give (11R)-7α,12-dihydroxyeudesm-4-ene-3,6-dione. Transformation of some other 12-hydroxyeudesman-6-ones into 7,12-dihydroxyeudesman-6-ones was also examined.
Synthesis of 3′,4′,6′-Trideoxy-6′-Fluorokanamycin C, 3′,4′-Dideoxy-6′-C-(fluoromethyl)kanamycin B, and Their 1-N-[(S)-4-Amino-2-hydroxybutanoyl] Derivatives
Authors: Umemura Eijiro , Tsuchiya Tsutomu , Umezawa Sumio
Published: July 2006

3′,4′,6′-Trideoxy-6′-fluorokanamycin C (5) has been prepared by treatment of a protected kanamycin C derivative having the free 6-hydroxyl group with DAST, as the key step. Two 3′,4′-dideoxy-6′-C-(fluoromethyl)kanamycin B′s (17a and 17b) have been prepared from a 5′-C-aldehyde derivative of kanamycin C through a sequence of reactions involving nitromethane condensation and 6′,7′-(N-tosylepimino)-ring opening with KHF2, as the key steps. 1-N-[(S)-4-Amino-2-hydroxybutanoyl] derivatives of 5 and 17a were prepared by coupling of the [(S)-4-amino-2-hydroxybutanoyl] residue to the 1-amino group of 5 and 17a by utilizing the zinc acetate-ethyl trifluoroacetate method. Biological effects caused by the introduction of the fluorine atom in these products were discussed based on the chemical character of fluorine.