bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dielectric Relaxation and Molecular Structure. XIV. The Dielectric Behavior of Six Isomeric Pentyl Alcohols
Authors: Sato Hiroshi , Koshii Taro , Takahashi Hiroaki , Higasi Keniti 
Published: July 2006

Abstract
The dielectric constants and losses of six isomeric pentyl alcohols have been measured in the frequency range of 1–0.35 GHz at 25 °C. The relaxation times of these alcohols decrease with an increase in the steric hindrance of the hydroxyl group.
Abnormal Grignard Reaction of 2,4,6-Trimethylbenzophenone: An Electron-transfer Mechanism
Authors: Okubo Masao 
Published: July 2006

Abstract
The reaction of 2,4,6-trimethylbenzophenone with phenyl-MgBr in tetrahydrofuran was examined by ESR technique. A high amount of the ketyl radical was detected. An electron-transfer mechanism was proposed to explain the formation of o-biphenylyl mesityl ketone.
Dielectric Relaxation and Molecular Structure. XV. A Further Study of the Benzene Effect of 1,2-Dichloroethane and Related Molecules
Authors: Shiratori Naoyuki , Takahashi Hiroaki , Higasi Keniti 
Published: July 2006

Abstract
The dielectric relaxation times, τ, and dipole moments, μ, of 1,2-dichloroethane (A), cis-1,2-dichloroethylene(B), 1,3-dichloropropane(C), o-dichlorobenzene(D), and 1-chloro-2-propanone(E) have been measured in two aromatic and two aliphatic nonpolar solvents. The results are as follows: both the τ and μ of (A) and (E) are exceptionally large in aromatic solvents, showing the benzene effect; (B) and (C) have large τ but normal μ values in aromatic solvents, while (D) shows normal effects of the solvent upon both τ and μ in two different sets of solvents. Finally, the intetmolecular interaction between the solute and the solvent is discussed with special regard to the origin of the benzene effect.
Chemical Equilibria between a Lanthanide Shift Reagent and n-Hexylamine in Chloroform
Authors: Inagaki Fuyuhiko , Tasumi Mitsuo , Miyazawa Tatsuo 
Published: July 2006

Abstract
The Eu(fod)3-induced 1H NMR shifts of n-hexylamine were observed using two kinds of dilution methods. The results are analyzed in terms of the chemical equilibria among the shift reagent (L), substrate (S), 1 : 1 (LS), and 1 : 2 (LS2) complexes. The association constants and the induced shifts intrinsic to the LS and LS2 complexes are evaluated accurately by fitting the theoretical curves to the observed data. The values obtained are utilized to confirm the validity and usefulness of the extrapolation method proposed previously to determine the shift ratios for the LS complex.
The PMR Study of the cis-trans Isomerization of the Dimethylaluminum Methylphenylamide Dimer, [(CH3)2AlN(CH3)(C6H5)]2
Authors: Wakatsuki Kizuku , Tanaka Toshio 
Published: July 2006

Abstract
The dimethylaluminum methylphenylamide dimer exists as an equilibrium mixture of trans- (I) and cis-isomers (II) with respect to the four-membered Al2N2 skeleton, and the latter involves the magnetic non-equivalence of the Al–CH3 groups. Thermodynamic parameters for the cis to trans isomerization are obtained from the variable-temperature PMR spectra; ΔH=4.47±0.09 kj·mol−1 and ΔS=1.74±0.48 J·deg−1mol−1. The isomerization is markedly accelerated by adding 4-methylpyridine or tetrahydrofuran. A possible mechanism of the isomerization is proposed.
Combustion of Polymer Fuel-Spheres at Elevated Pressures
Authors: Saito Takeo , Iwama Akira 
Published: July 2006

Abstract
Two kinds of polymer spheres polyurethane (PU) and carboxyl-terminated poly butadiene (CTPB), ca. 3 and 5 mm, respectively, in diameter and used currently as fuel and/or binder constituents in solid and hybrid rocket propellants, were ignited electrically with a nichrome fiber in several oxidizing gases over the range 5–30 kg/cm2. Their combustion phenomena were studied photographically with a 16 mm movie camera. The combustion flame was observed by means of direct photographs, both the variation of diameter with time and the location of contact surface being measured with shadow photographs. It was shown that PU spheres are entirely liquefied, involving slight swelling just after ignition, and then burn in a similar manner to that of distilled hydrocarbon droplets. CTPB spheres were found to expand remarkably after ignition. At the first stage the surrounding product gases formed a diffusion flame, their apparent diameters remaining nearly constant for a short time. At the second stage the remainder of the carbonaceous substance continued to burn, turning to surface combustion. It can be predicted that in an actual rocket combustion chamber the surface of the fuel-binder for PU propellants is wet and that of GTPB propellants is covered with carbonaceous layer during the course of steady state burning. The overall mass burning rate is proportional to a half and 0.3 power of total pressure for PU and CTPB, respectively, depending slightly on the kind of inert gas for dilution of the oxidizing atmosphere in both cases. A combustion model for CTPB is presented and Compared with experimental results.
A Theory of Ion Association as a Complement of the Debye-Hückel Theory
Authors: Yokoyama Haruhiko , Yamatera Hideo 
Published: July 2006

Abstract
The classical Debye-Hückel theory of strong electrolyte solutions was re-examined in order to explain ion association. Regarding a symmetrical electrolyte in very dilute solutions, a more precise expression was derived for excess chemical potential due to electrostatic ion-ion interactions. This expression has, in addition to the Debye-Hückel term, a supplementary term resulting from a more proper account of the energy of the interactions of ions existing near each other. If the concept of ion association is taken as a complement of the Debye-Hückel theory, the contribution to the chemical potential of the electrolyte from ion association should correspond to the supplementary term. The following equation was thus obtained for the ion-association constant:
K=(8πNa^3/1000) \overset∞\undersetn=1∑b^2n+2/[(2n+2)! (2n-1)]
This equation is in agreement with that derived by Ebeling on the basis of the cluster theory and has an asymptotic representation (at b→∞) in common with Bjerrum’s. For practical b values, the present equation has the merit that it gives moderate K values, decreasing monotonously with an increase in the a value, and eliminates the disadvantages of Fuoss’s result, giving a minimum K value at b=3, and of Bjerrum’s, giving K=0 at ≤2.
Fluorescence Polarization of Intramolecular EDA Complexes in (9,10-Dicyanoanthracene)-(CH2)n-(Naphthalene)
Authors: Mimura Tsutomu , Itoh Michiya , Okamoto Toshihiko 
Published: July 2006

Abstract
Fluorescence of the intramolecular EDA complex was observed below∼140 K in the nonpolar solution of (9,10-dicyanoanthracene)-(CH2)n-(naphthalene), n=2. The fluorescence and excitation polarizations of these EDA (n=2 and 3) complexes at 77 K were determined.
Semi-empirical SCF-MO Studies of Electronic Structures of Pt-Ethylene and Pt-Acetylene Complexes
Authors: Sakaki Shigeyoshi , Kato Hiroshi , Kawamura Takashi 
Published: July 2006

Abstract
A parametrization in a CNDO-type MO method is presented for Pt compounds. By the use of this parametrization, the electronic spectra of PtCl42− are calculated; they agree well with the experimental spectra in transition energies and assignments. MO calculations with this parametrization are carried out on Pt(II)–ethylene, Pt(II)–acetylene, Pt(0)–ethylene, and Pt(0)–acetylene complexes. The calculated transition energies of Zeise’s salt also agree well with the experimental values. In Pt(II) complexes, electrons are donated from ethylene and acetylene to the Pt atom, while they are little donated in Pt(0) complexes. The TT-bonds of ethylene and acetylene are weaker in Pt(0) complexes than those in Pt(II) complexes. These results are the consequence of the stronger π-acceptor coordination bond in Pt(0) complexes than in Pt(II) complexes. Acetylene coordinates to the Pt atom more strongly than does ethylene. The coordination bonds of ethylene and acetylene are stronger in Pt(0) complexes than in Pt(II) complexes.
Photolysis of Cyclopropane at 1470 and 1634 Å
Authors: Shibuya Kazuhiko , Obi Kin-ichi , Tanaka Ikuzo 
Published: July 2006

Abstract
The vacuum-ultraviolet photolysis of cyclopropane in the gas phase has been investigated at room temperature at excitation wavelengths 1470 and 1634 Å. Primary processes are discussed in terms of variations of product yield as a function of conversion and in the presence of additives such as NO, C2D4, and H2. The relative yields of decomposition are determined at both wavelengths. The main primary process is cyclo-C3H6+hv→C2H4+CH2, the yield being 67% at 1470 Å (69% at 1634 Å). The observed product yield responsible for methylene is much less than that for ethylene. However, the yields become equal in the photolysis of cyclopropane with excess hydrogen. The other primary processes are as follows in order of decreasing importance; cyclo-C3H6+hv→C2H3+CH3, 19% (18%), cyclo-C3H6+hv→C3H4+2H, 9% (7%), cyclo-C3H6+hv→C2H2+CH3+H, 3% (4%), cyclo-C3H6+hv→C2H2+CH4, 1% (1%).
Electron Pair Concept and an Extension of the Penney-Dirac Bond Order
Authors: Okada Takashi , Fueno Takayuki 
Published: July 2006

Abstract
The density functions representing electron pairs are extracted from two-electron density matrices by operating irreducible tensor operators in a two-electron spin space. Properties of these functions are examined, and the generalized Penney-Dirac bond orders are defined between atomic orbitals. Significance of the bond orders in chemical valence problems is discussed.
Synthesis of (2R, 3S, 4S)-4-Amino-3-hydroxy-2-methyl-5-(3-pyridyl)pentanoic Acid Present in Antibiotic Pyridomycin
Authors: Kinoshita Mitsuhiro , Mariyama Satoshi 
Published: July 2006

Abstract
Natural (2R,3S,4S)-4-arnino-3-hydroxy-2-methyl-5-(3-pyridyl)pentanoic acid (1) present in antibiotic pyridomycin was synthesized. The 5,6-anhydro-1,2-O-isopropylidene-3-C-methyl-α-d-allofuranose (4) was prepared from (the known) 3-deoxy-1,2;5,6-di-O-isopropylidene-3-C-methyl-α-d-allofuranose (2). Regiospecific introduction of 3-pyridyl group to the C–6 of 4 was effected by 3-pyridyllithium. The product (5) was converted to the 5-azido derivative (7) by the SN2 substitution reaction of the 5-mesylate (6) of 5. Hydrolysis of 7 followed by two-stage oxidation with periodate-bromine in aqueous acetic acid afforded (2R,3S,4S)-4-azido-3-formyloxy-2-methyl-5-(3-pyridyl) pentanoic acid (9), which was transformed to the dihydrochloride of 1.
Studies of the π→π* Absorption Bands of 9,10-Phenanthrenequinone
Authors: Kuboyama Akira , Kobayashi Fumio , Morokuma Satomi 
Published: July 2006

Abstract
The π→π* S–S absorption spectra of 9,10-phenanthrenequinone and 3-bromophenanthrenequinone in solutions up to the vacuum. UV region were obtained. On the other hand, MO calculations of the π-electronic systems of these quinones were carried out by means of the P–P–P method. The π→π* absorption bands of these quinones were assigned on the basis of the calculated results. The blue-shift of the longest-wavelength π→π* band of phenanthrenequinone due to the bromine-atom substitution at its 3-position was observed. Similar facts are found in aromatic carbonyl compounds, fluorenone and acetophenone.
The Crystal and Molecular Structure of cis-2,2-Diphenyl-3,4-dichlorothietane 1,1-Dioxide
Authors: Kumakura Shigekazu 
Published: July 2006

Abstract
The title compound crystallizes in the space group C2⁄c with a=18.85(2), b=6.15(1), c=27.94(2) Å, β=111.3(1)°, and Z=8. The structure was determined from the photographic X-ray data and was refined by the block-diagonal least-squares method to R=0.10 for 1006 observed reflections. Centrosymmetrically related molecules in the crystal form a dimer by means of weak intermolecular C–H···O hydrogen bonds. The thietane skeleton of the compound is bent with the dihedral angle, CαSCα/CαCβCα, of 148.7°. The average distance of the C–S bonds is 1.87 Å, while that of the C–C’s in the thietane ring is 1.58 Å. The conformation of the C–Cl bonds with respect to the thietane ring is (3a4e). The transannular S···Cl distance is 3.42 Å. The CNDO/2 calculation reveals that the 3d–3p bonding overlap is present between these atoms. The bond angles involving the ring substituents deviate greatly from those observed for cis-2,2-diphenyl-3,4-dichlorothietane. These deformations may be explained in terms of dipole-dipole interactions.
The Electronic Structures of Several Aliphatic Carbonyls. The Effects of Polar Substituents
Authors: Yonezawa Yoshiro , Fueno Takayuki 
Published: July 2006

Abstract
The electronic structures of several aliphatic carbonyls, X2CO, CH3COX, and (XCO)2 (X=H, F, CN, CH3), have been investigated by the INDO method. Variations in the calculated electron density, the nπ*-excitation energy, the electron affinity, and the ionization potential with α-X substitution are explained qualitatively in terms of the σ-attracting and π-donating character of F, the π-attracting nature of CN and XCO, and the σ,π-donating property of CH3. The lowest 3nπ* excitation energies and ionization potentials calculated by the UHF method are in reasonable agreement with the experimental values in most cases. The partitioning of the total energy suggests that the C–O bonds of X2CO compounds in the lowest 3nπ* state and the radical anions derived from them are somewhat longer than those of the parent molecules, primarily because of the decrease in the electron-core attraction. The C–C bonds in some (XCO)2 compounds appear to be cloven as easily as the C–X one on thermal activation and electron impact.
Enthalpies of Combustion of Organic Compounds. II. l- and d-Glutamic Acid
Authors: Sakiyama Minoru , Seki Syûzô 
Published: July 2006

Abstract
Enthalpies of combustion of l- and d-glutamic acid in the crystalline state have been measured by oxygen bomb calorimetry. Standard enthalpies of formation at 298.15 K have been determined.
The Determination of Formation Constants by Measurements of Molar-volume Changes
Authors: Watanabe Norio , Takamoto Susumu 
Published: July 2006

Abstract
Density measurements were made with a solution containing equivalent amounts of diethylenetriamine and the copper(II) ion, and with solutions of different concentrations of potassium hydroxide. The measurements were also made with systems in which the above-mentioned solutions were mixed. The molar-volume changes due to the complex formation were calculated from the density. The results were used for the calculation of the formation constant of the monohydroxo-diethylenetriamine-copper(II) ion.
Dielectric Relaxation and Molecular Structure. XVI. Dielectric Behavior of Tertiary Alcohols
Authors: Koshii Taro , Takahashi Hiroaki , Higasi Keniti 
Published: July 2006

Abstract
The relaxation time and the activation energy of the principal dispersion of tertiary alcohols do not increase but decrease with increase in the number of the carbon atoms in the molecule. This observation seems to be in accord with a hypothesis that the principal dispersion is associated with the size of the hydrogen-bonded cluster of alcohols.
The Cycloaddition Reaction of Isonitrile to Ketenimine Formed by the Reaction of Isonitrile with Carbene
Authors: Obata Naruyoshi , Mizuno Haruo , Koitabashi Takeo , Takizawa Takeo 
Published: July 2006

Abstract
The reaction of several 2-, 4-, and/or 6-fnethyl-substituted phenylisonitrile with dihalocarbene and diphenylcarbene has been studied. The reaction of methyl-substituted phenylisonitrile with dihalocarbene gave indolenine or indoloquinoline derivatives via ketenimine intermediate which might be produced by α-addition of carbene to isonitrile. In contrast, the reaction of 2,6-dimethylphenylisonitrile with diphenylcarbene presumably formed by photolysis of diphenyldiazomethane gave N-(2,6-dimethylphenyl)diphenylketenimine, and further caused a cycloaddition reaction with isonitrile to yield indonimine derivatives. The structure of these products are discussed on the basis of the spectral data and chemical reactions. The mechanistic pathway of these reactions and the effect of methyl substituent in the cyclization stage are also discussed.
Synthetic Studies of Laurencin and Related Compounds. I. The Synthesis of t-3-Bromo-r-2,c-8-diethyl-3,4,7,8-tetrahydro-2H-oxocin
Authors: Masamune Tadashi , Numata Satoshi , Matsue Hajime , Matsuyuki Akira , Sato Takehiro , Murase Hisashi 
Published: July 2006

Abstract
The synthesis of the titled bromohydrooxocin (2), one of model compounds for synthetic approaches to laurencin (1), is described, trans- and cis-2,5-Diethyl-2,5-dihydrofurans (25), prepared by treatment of furan with bromine and then with ethyl magnesium bromide, was submitted, after oxidation with ozone, to the Robinson-Schöpf condensation with methylamine to give trans- and cis-2,4-diethylbicyclononanones (19a and 19b), whose configurations were discussed on the NMR spectra. These compounds were converted into trans- and cis-diethylhydrooxocinones (38a and 38b), respectively, according to a six-step process analogous to the Paguette procedure. It is to be noted that (i) thermally induced, intramolecular dienyl 1,5-hydrogen transfer (36 to 37), one of the key reactions in the process, took place without difficulty with cis-aminodiene (36b), while the rearrangement did not proceed smoothly with trans-aminodiene (36a), and (ii) trans-ketone (38a) was isomerized readily into cis-ketone (38b). Further hydride reduction of cis-ketone (38b) followed by bromination with carbon tetrabromide and triphenylphosphine yielded the aimed bromohydrooxocin (2) as a major product, which possessed the same relative configuration concerning the ring substituents as laurencin (1).
The Synthesis of 11-(2′-Dimethylaminoethyl)-5-methyl-5,11-dihydrodibenzo[b,e][1,4]thiazepin and Related Compounds. Neurotropic and Psychotropic Agents
Authors: Ueda Ikuo , Umio Suminori 
Published: July 2006

Abstract
The synthesis of 11-(2′-dimethylaminoethyl)-5-methyl-5,11-dihydrodibenzo[b,e][1,4]thiazepin and related compounds is described. 11-Lithiolated 5-methyl-5,11-dihydrodibenzo[b,e][1,4]thiazepin (18) was employed as the key intermediate in the preparation of these compounds.
Group Interactions in Polyelectrolytes. X. The Animation Kinetics of Poly(vinyl haloacetals) and Related Compounds
Authors: Kawabe Hiroshi 
Published: July 2006

Abstract
Polyvinyl chloroacetal (PVCA) and polyvinyl bromoacetal (PVBA) were prepared from polyvinyl alcohol, whose acetal contents were close to the value expected on the basis of Flory’s calculation for the intramolecular reaction between neighboring substituents. The amination of these polyvinyl haloacetals and polyvinyl chloroethyl ether with 2-aminobutanol and diethanolamine was investigated kinetically in dimethyl sulfoxide. The ΔG\eweq values in the amination of these polymers were much higher than that of chloromethylated polystyrene (CMPS) reported previously; this was because of their higher ΔH\eweq values. The lower ΔH\eweq of CMPS was ascribed to the resonance structure of the activation complex due to the phenyl substituent at the α-carbon of the chloro-methyl group. This was ascertained by comparing the ΔH\eweq value in the amination of phenethyl chloride with that of benzyl chloride. The amination of PVBA was faster than that of PVCA as a result of the lower ΔH\eweq of the former.
Hydrogenolyses of Halo-9,9′: 9′,9″-terfluorenyls with the Raney Nickel Catalyst
Authors: Minabe Masahiro , Suzuki Kazuo 
Published: July 2006

Abstract
2,7-Di- and 2- halo-9,9′: 9′,9″-terfluorenyls were treated with the Raney nickel catalyst to give 9,9′: 9′,9″-terfluorenyl isomers (mp 293 °C (dec) (I) and mp 257 °C (dec) (II)), fluorene (III), 9,9′-bifluorenyl (IV), halofluorene, and/or 1,2,3,4,4a,9a-hexahydrofluorene (V). The conformation around the C9–C9′–C9″ single bonds of these halo-9,9′: 9′,9″-terfluorenyls were concluded to be s-cis, s-cis, identical with those of the parent hydrocarbon I. These assignments were confirmed by hydrogenolyzing 9,9″-dideuterio-2,7-dihalo-9,9′ : 9′,9″-terfluorenyls. The chemical shifts of the 9- and 9″-methine protons in these haloterfluorenyls were explained in terms of the torsional conformations of the molecules.
α,β-Unsaturated Carboxylic Acid Derivatives. VIII. The Synthesis and Reaction of Esters N-Acyl-N-bromo-α-dehydroamino Acid
Authors: Shin Chung-gi , Nanjo Katsumi , Nishino Takashi , Sato Yoshiaki , Yoshimura Juji 
Published: July 2006

Abstract
The addition of bromine to t-butyl 2-(N-acylamino)-2-alkenoate (3) was accompanied by the elimination of hydrogen bromide and the decomposition of the ester group to give 2-(N-acylamino)-3-bromo-2-alkenoic acid, while the bromination of 3 with NBS gave the corresponding N-bromo derivative (7), whose bromine atom gradually migrates to give t-butyl 2-(N-acylamino)-3-bromo-2-alkenoate. The substitution of the bromine of 7 with nucleophiles gave, successively, the corresponding N-methoxy, N-benzyloxy and N-cyano derivatives, while that with sodium azide gave the corresponding migration products. The structures of the new compounds were assigned.
Substituent Effect on the Anomeric Effect in 1,3,5-Trithiane Derivatives
Authors: Oki Michinori , Endo Toshiyuki , Sugawara Tadashi 
Published: July 2006

Abstract
Anomeric effect in a series of 2-alkylthio- and 2-arylthio-1,3,5-trithianes has been studied by PMR spectroscopy to investigate the substituent effect on the anomeric effect. A remarkable steric effect is found in 2-t-butylthio-1,3,5-trithiane: the equatorial conformer is slightly favored over the axial one. The electron-withdrawing substituent in 2-arylthio-1,3,5-trithiane enhanced the anomeric effect. The origin of the steric and electric-electronic effect has been discussed on the ground of conformational analysis.
Kinetics of Reduction of Mercury(II) Chloride to Mercury(I) Chloride Induced by the Decomposition of Trioxalatocobaltate(III) in Acid Aqueous Solutions
Authors: Sato Toshiro , Kimura Masaru 
Published: July 2006

Abstract
The decomposition reaction of trioxalatocobaltate(III) complex in the presence of mercury(II) chloride in acid medium induces the reduction of the latter to mercury(I) chloride (calomel). The results are accounted for by a sequence of a chain reaction which is initiated by the intramolecular redox decomposition of trioxalatocobaltate(III). The formation rate of mercury(I) chloride is expressed as half order with respect to the concentrations of oxalic acid, mercury(II) chloride, and trioxalatocobaltate(III). Mechanisms and kinetics are presented to account for these facts.
Iodotrimethylpivalophenones and Iodotetramethylpivalophenones. Preparation and Properties
Authors: Suzuki Hitomi , Ishizaki Katsuro , Hanafusa Terukiyo 
Published: July 2006

Abstract
Three isomeric iodotrimethylpivalophenones and iodotetramethylpivalophenones have been prepared from the corresponding polymethylbenzenes by using the Perrier procedure of the Friedel-Crafts acylation, followed by the iodination of the resulting ketones with iodineperiodic acid dihydrate. Attempts to convert some of these hindered iodoketones to bis (pivaloyl)polymethylbenzenes via the Grignard reagent have failed.