bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substituent Effects in Heterogeneous Catalysis. III. Competitive Hydrogenation of Cyclohexanone and 2-Alkylcyclo-hexanones over Platinum Group Metals
Authors: Chihara Teiji , Tanaka Kazunori 
Published: July 2006

Abstract
Cyclohexanone (1) and one of its 2-alkyl (methyl, ethyl, or propyl) derivatives (2) were hydrogenated competitively at 30 °C in cyclohexane over platinum group metals. The alkyl derivatives 2 were all less reactive than 1 on all the catalysts used. The relative reactivity R2⁄R1 was given by log10(R2⁄R1)=σ**+k, with σ** depending only upon the substituent and k upon the catalyst. The greater the substituent size, the more negative was the substituent constant σ**. The catalyst-dependent constant K was in general more negative for a catalyst metal having a smaller atomic radius. The above empirical rate expression has been interpreted based on the absolute reaction rate theory. The σ** values calculated on this theoretical ground were in excellent agreement with the observed values.
ortho-Disubstituted F-Benzenes. I. Preparation of (F-Benzo)heterocyclic Compounds from F-Aniline and the Reactions of Some Intermediate (F-Phenyl)amino Compoundst
Authors: Inukai Yoshinari , Oono Yoshitsugu , Sonoda Takaaki , Kobayashi Hiroshi 
Published: July 2006

Abstract
With the intention of achieving the selective ortho-disubstitution of F-aniline via intramolecular nucleophilic cyclization, syntheses of some requisite intermediate (F-phenyl)amino compounds and (F-benzo)heterocyclic compounds were investigated. 2-Phenyl-F-benzoxazole, 2-phenyl-F-benzimidazole, and 2,3-dihydro-1,4-(F-denz)oxazin-3-one were obtained from the respective precursors: benz-F-anilide, N-(F-phenyl)benzamidine, and hydroxyacet-F-anilide. 2-Phenyl-F-benzothiazole was obtained by treating benz-F-anilide with phosphorus pentasulfide. Hydrolytic dehalogenation of haloacet-F-anilide failed to give hydroxyacet-F-anilide, but it was obtained successfully by catalytic debenzylation of benzyloxyacet-F-anilide. The reactions of iodoacet-F-anilide with silver nitrate and acetate yielded 2-nitrate and 2-acetate, respectively. The reaction with diamminesilver(I) nitrate resulted in a reductive deiodination which gave acet-F-anilide. This exceptional reactivity was ascribed to the strong electron-withdrawing effect of the F-phenyl group.
Syntheses of Polymerizable Carbodiimides Bearing a Terminal Vinyl Group
Authors: Kamogawa Hiroyoshi , Nanasawa Masato , Uehara Shigeki , Osawa Keisuke 
Published: July 2006

Abstract
N-(p- or m-Vinylphenyl)-N′-isopropyl- and cyclohexylcarbodiimides (3) have been synthesized in reasonable yields by first synthesizing the substituted ureas by the reactions p- or m-vinylaniline with isopropyl or cyclohexyl isocyanate in THF and the subsequent dehydration with p-toluenesulfonyl chloride in pyridine. The monomers 3 were found to polymerize smoothly with AIBN to afford vinyl polymers bearing the corresponding carbodiimide units as pendants in more or less cross-linked forms. The cross-linked insoluble polymers thus obtained can act as a dehydrative coupling agent in reactions such as the formation of peptide linkages.
Syntheses of Chlorozinc Complexes of 2(1H)-Pyridinethione and Their Mutual Transformations
Authors: Matsunami Satoshi , Fujimura Susumu , Okimoto Kiyomi , Masaki Mitsuo 
Published: July 2006

Abstract
Three types of zinc complexes, chlorotris[2(1H)-pyridinethionato]dizinc (3), dichlorotetrakis[2(1H)-pyridinethionato]trizinc (4), and chloro[2(1H)-pyridinethionato]zinc (5) were produced by the reactions of bis[2(1H)-pyridinethionato]zinc (2) and zinc chloride. The product in the reactions varies depending on the solvent. The mutual transformation reactions among 3, 4, 5, 2, and oxohexakis[2(1H)-pyridinethionato]tetrazinc were described. The formations of 5, 4, and 3 were explained by stepwise additions of 2 to zinc chloride based upon a view that these complexes are the adducts of 2 with zinc chloride in molar ratios of 1 : 1,2 : 1, and 3 : 1. Analogously, the correlation of the known polynuclear zinc complexes was systematically rationalized by stepwise additions of L2Zn (L=ligand) to ZnX2 (X=Cl or OH) or ZnO.
Synthesis and Sintering of Active Manganese(II) Zinc Ferrite Powders
Authors: Murthy M N Sankarshana , Deshpande C E , Bakare P P , Shrotri J J 
Published: July 2006

Abstract
Manganese(II) monoxide which is spontaneously oxidized in air is stabilized by solid solution with zinc oxide and then employed as a raw material in the synthesis of manganese(II) zinc ferrites in an inert atmosphere, giving thereby no chance for Mn2+ to get oxidized. Sintering is done in a static controlled atmosphere created by the thermal dissociation of pellets of active iron(III) oxide kept in oxygen-free nitrogen along with the ferrite toroids. The ferrite formation and the sintering are performed at 950 and 1150 °C respectively by employing active oxide raw materials.
Medium Effect on the Ionisation Constants of Some Hydroxy Derivatives of 1-Ethyl-2-styrylpyridinium and -quinolinium Iodides
Authors: Mahmoud M R , Abd-El-Hamide R , Idriss K A 
Published: July 2006

Abstract
The pKa values of 1-ethyl-2-(4 or 2-hydroxystyryl)pyridinium and -quinolinium iodides in different organic solvent–water mixtures were determined. The organic solvents used are methanol, ethanol, acetone, DMF and DMSO. The ionisation of the compounds under investigation depends largely on both the proportion and the nature of the organic co-solvent used. The ionisation constant decreases with increase in the proportion of the organic co-solvent in the medium. The major important effect responsible for this is the difference in the stabilization of base by donor hydrogen bond from solvent molecules. The free energy of solvation of both acid and proton by electrostatic interaction and that of the base by donor hydrogen bond from solvent molecules were calculated. The effect of the molecular structure of the compound on pKa is also discussed.
Rare Earth Complexes of 1-(2-Pyridylazo)-2-naphthol
Authors: Rao I M , Satyanarayana D , Agarwala Umesh 
Published: July 2006

Abstract
The rare earth complexes of 1-(2-pyridylazo)-2-naphthol (PAN=Hpan) are prepared in the solid state. The analytical, molecular weight and differential thermal analysis data of the complexes indicated the metal-ligand ratio as 1:3 with the general formulae Ln(pan)3·H2O (Ln=Pr3+, Nd3+, and Sm3+) and Ln(pan)3 (Ln=La3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, and Yb3+). Based on IR, UV, and visible absorption spectra, electrical conductance and magnetic susceptibility data, an octahedral structure having the metal ion bonded through nitrogen of azo and oxygen of carbonyl groups of the ligand has been postulated to these complexes.
Indirect Polarographic Estimation of Palladium
Authors: Kalapurna P B 
Published: July 2006

Abstract
Chemical displacement of palladium by mercury at the DME, has been found to be quantitative (that is, instantaneous and proportional to the id of mercury). Therefore the mercury(I) wave has been exploited for the indirect estimation of palladium using the DME. The conditions of estimation are standardized and the method applied to a mixture (dental alloy) containing palladium. The results are within experimental accuracy. The indirect method has certain advantages over the direct methods.
Preparation of Potassium Glycinatotrihydroxonitrosylruthenate(II)
Authors: Ishiyama Toshio , Matsumura Takashi 
Published: July 2006

Abstract
A new mono-glycinato complex of hydroxonitrosylruthenium(II), K[Ru(gly)(OH)3NO] was isolated by use of ion exchange resin from the product formed by the reaction of [RuCl3(H2O)2NO] with glycine. The complex was characterized by means of infrared, visible, and ultraviolet absorption spectra, capillary type isotachophoresis, magnetic moment and molar conductivity.
2,2′-Bipyridine Derivatives of Hexarhodium Carbonyl Cluster
Authors: Nomiya Kenji , Suzuki Hisashi 
Published: July 2006

Abstract
The properties of [Rh6(CO)12(bpy)2] (bpy:2,2′-bipyridine), prepared recently from substitution of carbonyl ligands in [Rh6(CO)16] by 2,2′-bipyridine have been investigated.
Preparations and Paramagnetic Contact Shifts of Some Tris(β-diketonato)vanadium(III) Complexes
Authors: Hiraki Katsuma , Onishi Masayoshi , Nakashima Yutaka , Obayashi Yayoi 
Published: July 2006

Abstract
New tris(dehydroacetato)-, tris (methylacetoacetato)-, and tris(ethyl acetopyruvato)vanadium(III) complexes were prepared and characterized by IR and NMR spectroscopies. Paramagnetic contact shifts of these complexes were discussed.
O-Methylation of Aromatic (E)-Oximes by Dimethylsulfonium Methylide
Authors: Tanimoto Shigeo , Yamadera Takashi , Sugimoto Toyonari , Okano Masaya 
Published: July 2006

Abstract
The reactions of dimethylsulfonium methylide with (E)-aldoxiroes and (E)-ketoximes proceeded smoothly at room temperature and gave moderately good yields of O-methyl (E)-aldoximes and O-methyl (E)-ketoximes, respectively. A possible scheme for the formation of O-methyl (E)-oximes has been discussed.
The Reaction of Methyl cis-Decahydro-5,8-dioxonaphthalene-1-carboxylates
Authors: Irikawa Hajime , Koyama Tsuyoshi , Okumura Yasuaki 
Published: July 2006

Abstract
Methyl cis-decahydro-5,8-dioxonaphthalene-1-carboxylates (1b and 1c) were derived from the Diels-Alder adducts of p-toluquinone or p-xyloquinone and methyl sorbate, respectively. The 13C NMR spectra of 1b and 1c suggest the existence of 1b and 1c in the form (A), which is in line with the formation of the keto γ-lactone from 1b and of the keto alcohol from 1c.
Stereoselectivity in Hydride Reduction of [n.3.2]Propellanones
Authors: Tobe Yoshito , Doi Akifumi , Kimura Koji , Odaira Yoshinobu 
Published: July 2006

Abstract
Stereoselectivity in hydride reduction of [n.3.2]propellanones is described. The observed stereoselectivity is attributed to conformational flexibility of the third ring, that is, from five- to eight-membered alidyclic rings.
Chemical Ionization Mass Spectrometry of Alkyl Nitrates and Nitrites
Authors: Das Rebati C , Koga Osamu , Suzuki Shin 
Published: July 2006

Abstract
The mass spectrometry of alkyl nitrites and alkyl nitrates with chemical ionization using methane and isobutane as reagent gases produces quasi-molecular ions, (M+1)+ and/or (M−1)+. These ions have maximum abundance for lower nitrates and nitrites. The chemical ionization mass spectrometry, in conjunction with gas chromatography, can be used for quantitative estimation of alkyl nitrates and nitrites in very low amounts.
Mixed Monolayers of Long Normal Chain Fatty Acids with Long Normal Chain Esters. II. Fatty Acids–Hexadecyl Acetate System
Authors: Matuo Hirosi , Motomura Kinsi , Matuura Ryohei 
Published: July 2006

Abstract
In order to clarify the effect of molecular structure on states and properties of mixed monolayers, surface pressure-area(π-A) curves of the two-component surface films of long normal chain fatty acids with hexadecyl acetate were measured at various compositions and temperatures. By use of thermodynamic analysis, the phase diagrams and partial molar enthalpy changes were calculated. For four systems studied in the present paper it was found that the diagram and enthalpy change vary characteristically with the number of carbon atoms of acids, but the dependence on the chain length of acid in fatty acid–hexadecyl acetate systems was very different from that in fatty acid–ethyl hexadecanoate systems.
The Crystal and Molecular Structures of 6-Deoxyversicolorin A and Versicolorin A, Metabolites from Aspergillus versicolor
Authors: Fukuyama Keiichi , Ashida Tamaichi , Katsube Yukiteru , Kakudo Masao 
Published: July 2006

Abstract
The structures of 6-deoxyversicolorin A, C18H10O6, and versicolorin A, C18H10O7, both isolated from Aspergillus versicolor, have been determined by the X-ray diffraction method. Both compounds crystallized in the space group P212121, with four molecules per unit cell. The cell dimensions of 6-deoxyversicolorin A are a=9.588, b=18.083, c=7.769 Å, and those of versicolorin A are a=9.524, b=18.629, c=7.629 Å. The structure was refined to R=0.055 for 6-deoxyversicolorin A and to R=0.043 for versicolorin A. Both structures are in agreement with those assigned by chemical and spectroscopic methods. There are two intramolecular hydrogen bonds in each molecule. Although an intermolecular hydrogen bond is present in versicolorin A, both structures are isotypic. The dimensions of the anthraquinone skeleton and the dihydrofuro[2,3-b]furan moiety are compared with those in related compounds whose structures have been determined.
Heterogeneous Catalysis in the Liquid-phase Oxidation of Olefins. III. Activity of Supported Vanadium–Chromium Binary Oxide Catalyst for the Oxidation of Cyclohexene
Authors: Takehira Katsuomi , Hayakawa Takashi , Ishikawa Toshio 
Published: July 2006

Abstract
The liquid-phase oxidation of cyclohexene has been conducted in benzene using a vanadium–chromium binary oxide supported on γ-Al2O3 or SiO2 as the catalyst. Three series of catalysts have been prepared by a kneading method using the following combinations of raw materials; NH4VO3+Cr(NO3)3·9H2O+alumina hydrate (Catalyst G), NH4VO3+(NH4)2CrO4+alumina hydrate (H), and NH4VO3+Cr(NO3)3·9H2O+silica sol (I). It has been found that the activity of the supported binary system is due to the interactions between the metal oxides and the carrier. The contributions of compounds such as the chromium isopolyvanadates appear to add to the above activity. The order of catalytic activity has been established as : I&gt;H&gt;G. The V2O5–SiO2 system in the I series showed the highest activity, but rapidly became depleted in the course of reaction. The second highest activity was given by Cr2O3–SiO2 system, on which Cr5+ species was observed. In both cases, the vanadium and chromium metal ions may be coordinated tetrahedrally on SiO2. The Cr2O3–Al2O3 in the H series contained Cr5+ ions and exhibited high activity which may be attributed to the tetrahedral configuration. It is thought that the tetrahedral complexes catalyze the autoxidation of cyclohexene by decomposing 1-cyclohexenyl hydroperoxide.
High-resolutional Calorimetric Study on Solid Solutions SnCl2(H2O)x(D2O)2−x
Authors: Tatsumi Masami , Matsuo Takasuke , Suga Hiroshi , Seki Syûzô 
Published: July 2006

Abstract
Heat capacities of the system of solid solutions SnCl2(H2O)x(D2O)2−x (x=2.00, 1.97, 1.75, 0.96, 0.50, 0.25, and 0.03) were measured by an adiabatic calorimeter capable of determinations of heat capacity with the temperature step of 5–10 mK. The heat capacity peak due to order-disorder change of hydrogens becomes broader and its transition temperature rises as the deuteron concentration is increased. A small first-order component was found in the crystals of x=2.00, 1.97, and 1.75. Measurements were repeated for aged crystals of x=0.96, 0.50, and 0.03. Nature of the phase transition has been discussed in analogy with the liquid-vapor critical point. From the heat capacity data around the glass transition it is concluded that the motion of the hydrogen atoms is strongly correlated with each other over a range whose size is large enough that fluctuation of the local isotopic composition from the average is negligible.
The Mechanism of the Spin-Spin Coupling of Dimethyllead(IV) Complexes with ONNO Quadridentate Schiff Base Ligands and the Magnetically Non-equivalent Methyl Protons of a Dimethyllead(IV) Complex
Authors: Majima Tetsuro , Kawasaki Yoshikane 
Published: July 2006

Abstract
Several dimethyllead(IV) complexes with ONNO quadridentate Schiff base ligands have been prepared. The spin-spin couplings between the lead nucleus and the azomethine proton of the ligands, 3J(207Pb–N=CH), as well as the lead-methyl proton couplings, 2J(207Pb–CH3), have been observed in various solvents. Both J values inclease with an increase in donor strength of the solvents. The mean excitation energy, the ΔE term in the Fermi contact term plays a dominating role for the lead-proton spin-spin coupling constants. Two methyl proton signals were, for the first time, found to be magnetically non-equivalent in the dimethyllead(IV) complex of sapr.
The Crystal and Molecular Structure of (Carboxymethyl)(pyridine)-(triphenylphosphine)palladium(II) Dichloromethane Solvate,[Pd(C2H2O2)(PPh3)(py)]·0.6 CH2Cl2
Authors: Kai Yasushi , Yasuoka Noritake , Kasai Nobutami 
Published: July 2006

Abstract
The molecular structure of carboxymethylpalladium(triphenylphosphine)pyridine has been determined by X-ray crystal structure analysis of its dichloromethane solvate, [Pd(C2H2O2)(PPh3)(py)]·0.6 CH2Cl2. The crystal belongs to the monoclinic system, space group P21/c, with four formula units in a cell with dimensions of a=8.791(4), b=14.623(7), c=19.862(5) Å, and β=101.53(4)°. R=0.091 for 2806 non-zero reflections. The feature of the structure is that the palladium atom is C,O-chelated by an acetic acid to form a four-membered ring [Pd–C=2.004 (16) and Pd–O=2.093 (11) Å], and the palladium atom has approximately square-planar geometry.
Circular Dichroism Spectra of Cobalt(III) Complexes of the Type, trans-[CoX2(1,3-Diamine)2]n+ (X=Cl−, CN−, or NH3)
Authors: Kashiwabara Kazuo , Kojima Masaaki , Fujita Junnosuke 
Published: July 2006

Abstract
Four new complexes of the type, trans-[Co(CN)2(1,3-diamine)2]+ were prepared, where 1,3-diamine is (S,S)-1,3-diphenyl-1,3-propanediamine, (R,R)-2,4-pentanediamine, (S)-1,3-butanediamine, or (S)-1-phenyl-1,3-propanediamine. Two diammine complexes of the same type with (S)-1,3-butanediamine and (S)-1-phenyl-1,3-propanediamine, and trans-[Co(CN)2((R,R)-1,2-diphenyl-1,2-ethanediamine)2]+ were also newly prepared. The circular dichroism (CD) spectra of the new complexes measured in several solvents were compared with those of the corresponding dichloro and diammine complexes. The CD spectra of the dicyano complexes of (S)-1,3-butanediamine and (S)-1-phenyl-1,3-propanediamine showed remarkable solvent dependence, while those of the other complexes small or little dependence.
Syntheses of N-Acyl Dipeptide Derivatives by Metalloproteinases
Authors: Isowa Yoshikazu , Ichikawa Tetsuya 
Published: July 2006

Abstract
X–Dipeptides (X=Z, Z(OMe), or Z(3Me)) have been catalytically synthesized by several microbial metalloproteinases. Among the enzymes used, Thermolysin showed the most remarkable ability in the coupling reactions of the esters or the amides of phenylalanine, leucine, isoleucine, and valine (and methionine in the case of the amide) with various X–amino acids. This method has been applied to the syntheses of ZPhePheOMe and ZPhePeOMe on a practical scale. Ammonium sulfate and sodium chloride had a marked effect on the condensed products, increasing the yield.
The Reaction of Group V Metal Alkoxides with Sulfur Dioxide and Selenium Dioxide
Authors: Ando Fumio , Koketsu Jugo , Ishii Yoshio 
Published: July 2006

Abstract
Trialkoxyarsines (I) and -stibines (II) react with sulfur dioxide to give the corresponding dialkyl sulfites and arsenic trioxide or polymeric residues containing antimony. The reactivity of the compounds (I) is very low, and the yield is poor. Reactions of I and II with selenium dioxide afford dialkyl selenites together with arsenic trioxide or the same polymeric residues containing antimony as in the case of the reaction with sulfur dioxide. The reaction followed a stoichiometry of three moles of trialkyl phosphites (III) and one mole of selenium dioxide yields a 2 : 1 molar ratio of the phosphates : the phosphoroselenoates. A similar reaction of the phosphites with selenium dioxide in a 2 : 1 stoichiometry gives the phosphates and red selenium quantitatively. The rate of oxidation of the phosphorus compounds by selenium dioxide decreases in the order Bu3P&gt;BuP(OEt)2&gt;P(OEt)3. Based on these results, the possible mechanisms have been discussed.
Synthesis of Decachloro-4-allylidenecyclopentene and Its Chemistry
Authors: Kusuda Kousuke , Roedig Alfred 
Published: July 2006

Abstract
Decachloro-4-allylidenecyclopentene (6) was synthesized by the reaction of pentachlorocyclopentadiene with hexachloropropene in the presence of anhydrous aluminium chloride. Hexachloro-2-allylidene-4-cyclopentene-1,3-dione (11), prepared from 6 by treatment with coned nitric acid, cyclized to hexachloro-2,5-dihydrocyclopenta[b]pyran-5-one (14) on heating. In a solvent such as acetone and acetonitrile, 4 rearranged to hexachloro-2,5-dihydrocyclopenta[b]pyran-2-one (18) at room temperature. The mechanism of this rearrangement is discussed. Hydrolysis of 14 by 90% sulfuric acid afforded tetrachloro-2,5-dihydrocyclopenta[b]pyran-2,5-dione (15), which was obtained directly from 6 by treatment with sulfuric acid. The reactions of 11 with anhydrous methanol, and of 15 with diazomethane were investigated.
S
N2 Reactions in Dipolar Aprotic Solvents. VII. Kinetic and Equilibrium Secondary α-Deuterium Isotope Effects in Chlorine Isotopic Exchange Reactions of Substituted Chloromethanes in Acetonitrile
Authors: Hayami Jun-ichi , Hihara Nobuhisa , Tanaka Nobuo , Kaji Aritsune 
Published: July 2006

Abstract
Secondary α-deuterium isotope effects were studied in the symmetrical nucleophilic substitution of the substituted chloromethanes in acetonitrile. The apparent second order rate coefficients show a significant isotope effect for chloromethyl aryl ethers and sulfides (1.11–1.14 per D), and an intermediate value of 1.05 for cinnamyl chlorides. 2-Arylethyl chlorides were shown to give an appreciable isotope effect of 1.03–1.04, and arylchloromethanes to give varying amount of the isotope effect from 1.006 to 1.050 depending upon the ring substituent. The deuterium label also gave rise to a significant equilibrium isotope effect on the substrate-nucleophile association in the reaction mixture. The observation of an equilibrium isotope effect suggested a possibility that an apparent isotope effect was a composite of the thermodynamic and the kinetic isotope effects. Thus the dissection resulted in a uniform and a fairly large kinetic isotope effect for all the activated substrates studied and in a small kinetic isotope effect for 2-arylethyl chloride. The results are explained in a framework of loose–tight transition state.
Photo-induced Transformation of Polyalkylbenzyl Thiocyanates into Polyalkylbenzyl Isothiocyanates. A Synthesis of Some Bis- and Tris(isothiocyanatomethyl)polymethylbenzenes by Multiple Thiocyanate Isomerization
Authors: Suzuki Hitomi , Usuki Michiyo , Hanafusa Terukiyo 
Published: July 2006

Abstract
Polyalkylbenzyl thiocyanates, upon irradiation in acetic acid, readily undergo reversible photoisomerization, giving an equilibrium mixture composed mostly of the corresponding isothiocyanates. Several new bis- and tris(isothiocyanatomethyl)polymethylbenzenes have been prepared by utilizing the photoinduced multiple thiocyanate isomerization.
Syntheses of Polymerizable Acetals. II. Readily Hydrolyzable Acetals from Citronellol and Vitamins
Authors: Kamogawa Hiroyoshi , Haramoto Yuichiro , Nanasawa Masato 
Published: July 2006

Abstract
Three perfume acetals and four vitamin acetals have been synthesized by the acid-catalyzed reactions of vinylbenzyloxy- and methoxy-substituted benzaldehydes with citronellol and the reactions of vinylbenzaldehyde with vitamins B6, C, B1 and B2, respectively. The acid hydrolyses of these novel acetals readily released citronellol and vitamins under mild conditions, some accelerations of the hydrolysis rate by the electron-donating para substituents being observed in the case of the perfume acetals.