bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ligand Isotopic Exchange of Tris(acetylacetonato)germanium(IV) Perchlorate in Organic Solvents
Authors: Nagasawa Akira , Saito Kazuo 
Published: July 2006

Abstract
The ligand isotopic exchange between tris(acetylacetonato)germanium(IV) perchlorate and acetylacetone[14C] has been studied in 1,1,2,2-tetrachloroethane (TCE), nitromethane (NM), and acetonitrile (AN), at 100–120°C. In these solvents, the rate formula was R=k[H2O][complex]; the concentrations of the complex, free ligand, and water in solution were in the ranges from 0.01 to 0.1 mol dm−3. The activation enthalpies and entropies for the k’s are 105, 98, and 90 kJ mol−1; and −25, −53, and −69 J K−1 mol−1, in TCE, NM, and AN, respectively. Influence of acid and base concentrations, and deuterium isotope effect on the rate in AN suggest that the rate controlling step of the exchange is governed by the ease of the proton transfer between the leaving and the incoming acac− in an intermediate.
Flameless Atomic Fluorescence Spectrometry of Mercury by Dispersive and Nondispersive Systems in Combination with Cold-vapor Technique
Authors: Nakahara Taketoshi , Tanaka Toshiaki , Musha Sôichirô 
Published: July 2006

Abstract
An atomic fluorescence spectrometer with dispersive and nondispersive systems has been designed and constructed. A flameless atomic fluorescence spectrometric method with the newly constructed spectrometer is described for the determination of mercury at the nanogram level. Mercury is reduced by tin(II) chloride and released from solution by a stream of argon into a quartz fluorescence cell. The fluorescence signal is measured by dispersive and nondispersive systems. Linear analytical working curves covering the mass range of mercury from the detection limits to approximately 10 and 1 μg have been established with dispersive and nondispersive systems, respectively. With the nondispersive system a detection limit of 0.003 ppb or 0.05 ng of mercury could readily be obtained. The present method was satisfactorily applied to the determination of mercury in wastewater samples.
Reactions of Bis(acetylacetonato)oxovanadium(IV) with Phenol and Its para-Substituted Derivatives
Authors: Taguchi Hiroshi , Isobe Kiyoshi , Nakamura Yukio , Kawaguchi Shinichi 
Published: July 2006

Abstract
Bis(acetylacetonato)oxovanadium(IV) reacts with phenol or its para-substituted derivatives in methanol, affording stable adducts with the composition of VO(acac)2(p-XC6H4OH), where X=H, NO2, CHO, COOH, Cl, or CH3. The magnetic and spectral data reveal that these are vanadium(IV) complexes containing the phenol as a neutral ligand. They show an unusually low ν(V=O) frequency of ≈900 cm−1 as compared with the value of 1000 cm−1 for the parent complex, and are presumed to have a polymeric structure with an infinite chain of V=O…V=O…. The phenol is connected by a hydrogen bond to one oxygen atom of an acetylacetonate ligand. The behavior of the complex in solution is also discussed. The addition of 1,10-phenanthroline or 2,2′-bipyridine to a reaction mixture of VO(acac)2 and nitrophenols results in phenolato complexes VO(OC6H5−nXn)(acac)(phen or bpy), where X=NO2 and n=1, 2, or 3. Two isomers of VO(OC6H2(NO2)3)(acac)(bpy) are isolated and characterized.
Photoaddition Reaction of 9,10-Phenanthrenequinone with Alicyclic Olefins. Product Distribution
Authors: Maruyama Kazuhiro , Iwai Tatsuaki , Naruta Yoshinori , Otsuki Tetsuo , Miyagi Yo 
Published: July 2006

Abstract
The phtoaddition reaction of 9,10-phenanthrenequinone (1) with several alicyclic olefins (6) has been investigated. In addition to the expected products, dihydrodioxin(2) and keto oxetane (3), the hydroxydihydrofuran derivative (4, 5) were found. Product distribution was shown to be deeply dependent on the structure of the olefins. Product 4 has been shown to be produced via the photorearrangement of 3.
Reduction of Acetals with TiCl4–LiAlH4
Authors: Ishikawa Hiroshi , Mukaiyama Teruaki 
Published: July 2006

Abstract
The reduction of dialkyl acetals derived from aromatic aldehydes and ketones with TiCl4–LiAlH4 in THF or diethyl ether at room temperature afforded the coupling products, pinacol ethers or olefins, in high yields. On the other hand, when acetals derived from aliphatic aldehydes and ketones were treated with TiCl4–LiAlH4 in diethyl ether, the reductive dealkoxylation took place and the corresponding ethers were isolated in good yields. As to the reaction mechanism we propose that Ti(II) is the reactive species in reductive coupling reaction of acetals derived from aromatic aldehydes and ketones, and that Ti(0)–H2AlCl complex may be the reactive species in reductive dealkoxylation of acetals derived frcm aliphatic aldehydes and ketones.
Branched-chain Sugars. XI. Synthesis of 2,3,6-Trideoxy-3-C,4-O-dimethyl-3-nitro-d-arabino-hexopyranose (d-Evernitrose)
Authors: Yoshimura Juji , Matsuzawa Masafumi , Funabashi Masuo 
Published: July 2006

Abstract
2,3,6-Trideoxy-3-C, 4-O-dimethyl-3-nitro-d-arabino-hexopyranose was synthesized by the oxidation of methyl α-glycoside of the corresponding 3-amino derivative with m-chloroperbenzoic acid followed by hydrolysis. The 3-amino derivative was synthesized from methyl 4,6-O-benzylidene-2-deoxy-α-d-erythro-hexopyranosid-3-ulose by introduction of the amino-branching function according to the method of Bourgeois, followed by 6-deoxygenation and 4-O-methylation.
Selective Dimerization of Ethylene Catalyzed by Halogenotris-(triphenylphosphine)cobalt(I) Complex-Lewis Acid
Authors: Kawakami Kiyoshi , Mizoroki Tsutomu , Ozaki Atsumu 
Published: July 2006

Abstract
Dimerization of ethylene is highly selectively catalyzed by CoX(PPh3)3 (X=Cl, Br, and I) in the presence of Lewis acid in halobenzene under mild conditions. The catalytic activity is significantly affected by the solvent, bromobenzene being the most effective. The role of BF3·OEt2 seems to be formation of a one-to-one complex of Co(I) and BF3, since the rate of ethylene dimerization attains a plateau on addition of equimolar amount of BF3·OEt2. The isomerization of 1-pentene is enhanced by addition of molecular hydrogen or ethylene to the catalyst system. The isotopic scrambling between C2H4 and C2D4 takes place faster than dimerization. The results are in line with hydridocobalt intermediate formed by the oxidative addition of ethylene to Co(I) complex.
Synthesis of 6-O-Acyl Derivatives of Immunoadjuvant Active N-Acetylmuramyl-l-alanyl-d-isoglutamine
Authors: Kusumoto Shoichi , Okada Satoshi , Yamamoto Koji , Shiba Tetsuo 
Published: July 2006

Abstract
Seven acyl derivatives of N-acetylmuramyl-l-alanyl-d-isoglutamine, which had previously been shown to be a minimum structure required for the immunoadjuvant activity, were synthesized in order to evaluate the significance of lipophilicity on the adjuvant activity and on the possible antitumor effect. Among them, are included 6-O-docosanoyl, stearoyl, lauroyl, octanoyl, butyryl, acetyl, and 4,6-di-O-acetyl derivatives. Some of these compounds were found to serve an improvement in the administration method to living body.
Studies of Peptide Antibiotics. XXXIX. Syntheses of Gramicidin S Analogs Containing l-Histidine in Place of l-Ornithine
Authors: Nonaka Kazuhiko , Sato Kazuki , Terada Shigeyuki , Kato Tetsuo , Izumiya Nobuo 
Published: July 2006

Abstract
Two analogs of gramicidin S, [2-l-histidine]-gramicidin S (14) and [2,2′-di-l-histidine]-gramicidin S (19), were synthesized to compare the biological role of δ-amino groups in l-ornithine residues in the antibiotic with that of weakly basic imidazolyl groups in l-histidine residues. Compound 14 exhibited identical activity to that of gramicidin S, but 19 was only 1/8 as active. The optical rotatory dispersions of these analogs and gramicidin S were nearly the same: molecular conformation of these peptides must be very similar. Compounds 14 and 19 showed esterolytic activity against p-nitrophenyl acetate. The activity of 14 was higher than that of imidazole, 14 being more active than 19.
The Sensitized Photooxidation of Cycloheptatriene (Tropilidene). Isolation and Thermal Isomerization of (4π+2π) Cycloadduct, 8,9-Dioxabicyclo[3.2.2]-2,6-nonadiene, and Preparation of Tropone
Authors: Asao Toyonobu , Yagihara Morio , Kitahara Yoshio 
Published: July 2006

Abstract
The sensitized photooxidation of cycloheptatriene (tropilidene) in methanol afforded (4π+2π) cycloadduct; 8,9-dioxabicyclo[3.2.2]-2,6-nonadiene (1), 6-hydroxy-2,4-cycloheptadienone and 6-oxoheptadienal presumably derived from (6π+2π) cycloadduct, and small amounts of tropone and benzaldehyde. Mechanism of their formation are discussed. It was found that the treatment of the photooxidation mixture with trie thy lamine afforded tropone in about 50% yield. Thermal isomerization of 1 in refluxing xylene afforded cis-3,9-dioxatricyclo-[6.1.0.02.4]-5-nonene, 8-oxabicyclo[5.1.0]-4-octen-3-one and 4-hydroxy-2,6-cycloheptadienone.
A Convenient Method for the Synthesis of Dihydropyranobenzopyrandiones and Their Sulfur Analogs
Authors: Merchant J R , Dike S Y 
Published: July 2006

Abstract
A general and convenient synthesis is described of a number of 2,3-dihydro-4H,5H-pyrano[3,2-c][1]benzopyran-4,5-diones and 2,3-dihydro-4H,5H-pyrano[2,3-b][1]benzothiopyran-4,5-diones. It involves the condensation of 4-hydroxycoumarin derivatives and their thioanalogs with different α,β-unsaturated acids in the presence of PPA. Assignments of the structures in both the cases are based on analytical and spectroscopic evidence.
Studies on the Cannabinoid Field: Synthesis of New Cannabinoids from 4-Hydroxycoumarin and 4-Hydroxythiocoumarin by Pyridine-catalysed Condensation of Citral and Citronellal
Authors: Dike S Y , Merchant J R 
Published: July 2006

Abstract
The reaction of 4-hydroxycoumarin and 4-hydroxythiocoumarin with citral in basic as well as acidic conditions led to the formation of tetrahydrocannabiol derivatives. With citronellal, the above hydroxycoumarins afforded the corresponding hexahydrocannabiol derivatives in moderate yields. The structures and the stereochemistry of the compounds obtained are established on the basis of spectral-analytical evidence.
Kinetics and Mechanism of the Oxidation of the Esters of Mandelic Acid by Lead Tetraacetate
Authors: Banerji Kalyan K , Banerjee Sudheer K , Shanker Rama 
Published: July 2006

Abstract
The oxidation of eight esters of mandelic acid by lead tetraacetate in benzene solution has been studied. The product of the oxidation is the corresponding phenylglyoxylic ester. The oxidation is of first order with respect to the oxidant and second order to the ester. The reaction is catalysed by pyridine, the catalysed reaction being first order in pyridine. In the presence of pyridine, the reaction is first order with respect to each the oxidant and the ester. The oxidation of ethyl α-deuteriomandelate indicated a kinetic isotope effect. The activation parameters have been determined. The results have been interpreted in terms of a slow decomposition of lead tetraalkoxide derivative involving heterolysis of Pb–O bond.
Intermolecular Chelate Linkage Isomerism of the Hydroxyimino Group in the Nickel(II), Copper(II), and Palladium(II) Complexes of Quadridentate Schiff-base Ligands
Authors: Dixit N S , Sudha B P , Patel C C 
Published: July 2006

Abstract
The C-nitrosation of bivalent quadridentate β-imino ketone complexes of nickel(II), copper(II), and palladium(II), with nitrosating reagents has been investigated. The chemical analysis and spectroscopic results reveal that one of the α-CH groups of the coordinated lignad undergoes selective nitrosation forming mono(hydroxyimino) derivative. The hydroxyimino group introduced coordinates through either N- or O- atom to metal(II) by dislodging the carbonyl group already coordinated. This gives rise to two linkage isomers, one with N-bonded and the other with O-bonded hydroxyimino group in the case of nickel(II) (except for 1d) and palladium(II), and a single isomer with O-bonded hydroxyimino group in copper(II) complexes. The isomers obtained from 1b and 1i have been separated by column chromatography. In chloroform each of the isomers of nickel(II) isomerizes to give an equilibrium mixture of two isomers, but not those of copper(II) and palladium(II).
Reactivity of Organic Ions by Chemical Ionization Mass Spectrometry. II. Chemical Ionization Mass Spectra of Alkylbenzenes with Methane by Using a Quadrupole Mass Spectrometer
Authors: Iseda Kozo 
Published: July 2006

Abstract
The titled spectra have been determined at 75 °C. The (M+H)+ ion intensities for methylbenzenes decrease linearly with the number of methyl substituents. The (M+H)+ ion intensities for dialkylbenzenes decrease in the order o-&gt;m-&gt;p-, while those of trimethylbenzenes decrease in the order 1,2,3-&gt; 1,3,5-&gt;1,2,4-, and those of tetramethylbenzenes decrease in the order 1,2,3,4-&gt;1,2,3,5-&gt;1,2,4,5-.
Reactive Troponoids and o-Aminophenol. I. Synthesis of Cyclohepta[b][1,4]benzoxazine
Authors: Nozoe Tetsuo , Okai Harue , Someya Taichi 
Published: July 2006

Abstract
Cyclohepta[b][1,4]benzoxazine and 2-(o-hydroxyanilino)tropone were obtained by the reactions of 2-chloro- and 2-methoxytropone with o-aminophenol. A similar reaction with o-methoxylaniline gave 2-(o-methoxyanilino) tropone and 1-(o-methoxyanilino)-7-(o-methoxyphenylimino)-1,3,5-cycloheptatriene. The chemical and physical properties of cyclohepta[b][1,4]benzoxazine were discussed.
The Radiolysis of Binary Mixtures of Tetrahydrofuran with Benzene, Thiophene, Pyridine, and Nitrobenzene
Authors: Matsui Masao , Imamura Masashi 
Published: July 2006

Abstract
Binary mixtures of tetrahydrofuran (THF) with benzene, thiophene, and nitrobenzene were subjected to radiolysis with γ-rays. The THF–benzene mixture was also irradiated with 28.6 MeV 4He- and 90.9 MeV 12C-ions. For THF–benzene mixtures, similar deviations of G(H2) from the mixture law were observed for all the radiolyses; these results are regarded as being due to energy transfer from THF+, the precursor of hydrogen, to benzene. The total ionization yield of THF was calculated as 3.0–3.3 in G-units, irrespective of radiation and additives. This is on the basis of Hardwick’s procedure, in which the deviations of G(H2) are divided by the efficiency of the energy transfer. This result also indicates that the total ionization yield is independent of the nature of radiation, whose LET range is from 0.02 to 49.2 eV/Å.
The Crystal and Molecular Structure of N-Carboxy-γ-benzyl-l-glutamate Anhydride
Authors: Kanazawa Hitoshi , Kawai Tohru , Ohashi Yuji , Sasada Yoshio 
Published: July 2006

Abstract
The structure of N-carboxy-γ-benzyl-l-glutamate anhydride has been determined by X-ray analysis. The crystal is orthorhombic; space group, P212121; Z=4 with a=7.766(1), b=27.470(4), and c=5.948(1) Å. The structure was deduced by the direct method and refined to a final R value of 0.057 for 1504 observed reflections by the block-diagonal least-squares method. The hydrogen bond is formed between the imino group and the carbonyl group of the side chain. The dimension of the five-membered ring is affected by the intermolecular hydrogen bond as compared with the crystal structures of the other N-carboxy anhydrides of α-amino acid.
The Crystal and Molecular Structure of N-Carboxy-l-leucine Anhydride at −70°C
Authors: Kanazawa Hitoshi , Kawai Tohru , Ohashi Yuji , Sasada Yoshio 
Published: July 2006

Abstract
The crystal structure of N-carboxy-l-leucine anhydride has been determined by means of X-ray. The crystal is orthorhombic; space group, P212121; Z=4 with a=6.527(1), b=23.920(4), and c=5.527(1) Å. The structure was deduced by the direct method and refined to the final R value 0.049 for 624 observed reflections by the block-diagonal least-squares method. The N-carboxy anhydride rings are arranged in a layer form sandwiched by hydrophobic side chains. The highest polymerizability of this compound in the crystalline state is due to the sandwich structure.
Potential of Hydrocarbons for Photochemical Conversion of NO to NO2
Authors: Washida Nobuaki , Inoue Gen , Akimoto Hajime , Okuda Michio 
Published: July 2006

Abstract
The factor F, the number of NO molecules which are converted photochemically into NO2 when one hydrocarbon molecule is consumed, was determined for fourteen different hydrocarbons in the photochemical oxidation process. Experiments were carried out in a 67 dm3 Pyrex reaction chamber in which a mixture of hydrocarbon, NO, H2O, and air was irradiated by a xenon short arc lamp. In the range from low to middle conversion, hydrocarbons and NO decayed nearly exponentially, NO being converted into NO2. The observed value of F was approximately two for most of the hydrocarbons studied. The value is in line with the long chain mechanism involving OH radicals predicted by Heicklen et al. Only m-xylene gave a larger F value. Reaction sequences of the long chain mechanism caused by OH radicals were discussed, a generalized kinetic model for the chain mechanism being proposed. This will be useful for the atmospheric modeling of photochemical smog.
Solubility and Diffusion Coefficient of Sulfur in Copper
Authors: Fueki Kazuo , Ouchi Yasumasa 
Published: July 2006

Abstract
The solubility and diffusion coefficient of sulfur in copper were determined by a new method, wherein a thin copper(I) sulfide film was formed on the surface of a copper specimen and the decrement of its thickness after diffusion annealing was determined coulometrically. It was found that the solubility Cs could be represented by
logCs(ppm)=−0.616−0.410(104⁄T),
and the diffusion coefficient is given by
D=0.834×exp(−40900⁄RT)cm2s−1.
Molecular Structure and Conformation of Ethyl Methyl Sulfide as Studied by Gas Electron Diffraction
Authors: Oyanagi Kazuko , Kuchitsu Kozo 
Published: July 2006

Abstract
The bond distances (rg) and angles (rα structure) in ethyl methyl sulfide have been determined by gas electron diffraction as follows: average of C(methyl)–S and C(methylenc)–S=1.813±0.004 Å, C–C=1.536±0.008 Å, C–H=1.111±0.008 Å, ∠C–S–C=97.1±1.1°, ∠S–C–C=114.0±0.5°, ∠H–C–H=109.6±1.4°, where uncertainties represent estimated limits of experimental error. The two C–S lengths have been estimated independently with the aid of the rotational constants for the trans conformer reported by Hayashi et al.: C(methyl)–S=1.806±0.027 Å, C(methylene)–S=1.818±0.027 Å. The dihedral angle for the gauche conformer (66±9°) and the relative abundance of the trans and gauche conformers in the gas phase at 20 °C, nt⁄(nt+ng)=0.25±0.15, have also been determined.
Correlation between Relative Sensitivities for Electron Capture Detector and Chemical Structure of Aromatic Halogeno and Nitro Compounds
Authors: Hattori Yukikazu , Kuge Yoshio , Nakagawa Shigeru 
Published: July 2006

Abstract
Relative sensitivities of an electron capture detector (ECD, 63Ni) for aromatic halogeno and nitro compounds were measured at detector temperatures of 230, 290, and 320 °C. The effects of various substituents on the sensitivity of ECD were determined. A good correlation was recognized between the relative sensitivities of ECD and the positions of substituents for aromatic chloro, bromo, and nitro compounds. The plotted logarithm values of ECD sensitivities for aromatic chloro and bromo compounds vs. Hammett’s σ values of various substituents are not linear, but the plots for aromatic nitro compounds follow a straight line. Modified σ values (σH) were determined on the basis of the relative sensitivities of aromatic chloro compounds. Plots of aromatic chloro, bromo, and nitro compounds vs. σH values gave straight lines. The temperature dependence of electron capture coefficients for these compounds was determined using D.C. mode. The electron capture spectra obtained are similar to those using pulsed mode.
Studies of Inorganic Ion Exchangers. II. Effects of Sulfuric Acid on the Synthesis of Ti(HPO4)2·0–1/2H2O
Authors: Kobayashi Etsuro 
Published: July 2006

Abstract
In order to develop an inorganic ion exchanger for industrial use, sulfuric acid has been added to the reaction system of amorphous titanium(IV) phosphate and phosphoric acid. The effects of the additive on the formation of titanium(IV) hydrogenphosphate, a compound observed to have ion exchange affinities towards K+ and Cs+, have been investigated. Ti(HPO4)2·0–1/2H2O has been synthesized using the sulfuric acid solution of TiOSO4, an intermediate in the production process of titanium dioxide. The addition of sulfuric acid to phosphoric acid and a resulting mole ratio of H2SO4/H3PO4 greater than 0.14, produced a borderline in the formation of the monohydrate and hemihydrate within the temperature range of 148–155 °C Titanium(IV) hydrogenphosphate crystallized as fine particles (1–3 μ) by the double decomposition between the sulfuric acid solution of TiOSO4 and phosphoric acid. The X-ray diffraction pattern of the product obtained using the sulfuric acid solution of TiOSO4 above 160 °C compared favourably with that of the hemihydrate already reported. The composition was shown by the formula of Ti(HPO4)2·0–1/2H2O. In the X-ray diffraction pattern of Ti(HPO4)2·0–1/2H2O, two characteristic diffraction lines appeared at 11.6 and 9.21 Å; thus it has been assumed that the product is not a pure crystallite but a mixture of two or more species.
Solubility of Hexaamminenickel(II) Complexes in Aqueous Ammonia Solution and the Thermal Decomposition of Ammine Complexes of Nickel(II)
Authors: Sato Tsugio , Suda Takeshi , Uchida Hideki , Okabe Taijiro 
Published: July 2006

Abstract
The solubility of hexaamminenickel(II) complexes in aqueous ammonia solution (0 to 37 g-free NH3/100g-solv.) was investigated at temperatures 0–55 °C. It rapidly decreases with increase in free ammonia concentration but increases with rise in temperature. Hexaamminenickel(II) carbonate, sulfate, and chloride are slightly soluble at ammonia concentration above 30 g-free NH3/100 g-solv., but nitrate is considerably soluble even at ammonia concentration of 35 g-free NH3/100 g solv. The thermal decomposition of ammine complexes of nickel(II) was also investigated by means of TG and DTA under a streaming nitrogen gas atmosphere. Ammine complexes of nickel(II) decompose as shown in the following, the reaction orders and activation energies for steps a, b, c, and d being 0.5, 1.5, 1.0, and 0.5, and 16.5, 38.8, 25.3, and 79.4 kcal/mol, respectively.
(Remark: Graphics omitted.)
X-Ray diffraction data for [Ni(NH3)6]Cl2·0.5H2O, [Ni(NH3)6](NO3)2, [Ni(NH3)5]SO4·H2O, and [Ni(NH3)2]SO4 powder are given.
Inter- and Intramolecular Rhodium-Rhodium Interactions in Bis-(bidentate isocyanide)rhodium(I) Hexafluorophosphates
Authors: Kawakami Katsuhiko , Okajima Masaki , Tanaka Toshio 
Published: July 2006

Abstract
The reaction of [RhCl(1,5-C8H12)]2 with the stoichiometric amount of bidentate isocyanide followed by metathesis affords complexes of the types [Rh(L–L)2]PF6 (L–L=CN(CH2)8NC (1), CN(CH2)7NC (2)) and [Rh2(L–L)4](PF6)2 (L–L=CN(CH2)6NC (3), CN(CH2)4NC (4)). The electronic spectra at various concentrations reveal that in dilute solutions 1 and 2 exist as monomers with chelating isocyanides, while 3 and 4 form dimers with bridging isocyanides through intramolecular rhodium–rhodium interactions as the smallest unit. On the other hand, in concentrated solutions 1 and 2 form dimers and 4 tetramers through intermolecular Rh–Rh interactions.