bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Structure of Copolymers of l-Proline with γ-Benzyl-l-glutamate in Organic Solvents
Authors: Sakai Rume , Ikeda Shoichi , Isemura Toshizo 
Published: July 2006

Abstract
The equilibrium conformations of three copolymers of l-proline with β-benzyl-l-glutamate were studied in 1,2-dichloroethane, m-cresol, and dichloroacetic acid by measuring the optical rotatory dispersion and the infrared absorption spectra. In m-cresol and dichloroacetic acid, the proline residues take the trans-configuration. In m-cresol their incorporation into copolymers destroys the right-handed-α-helical conformation of glutamate residues. In 1,2-dichloroethane, the proline residues assume the cis-configuration if the sequence of proline residues is long enough. If it is short, they are in the trans-configuration. The poly-l-proline-I-helix can never coexist with the α-helix.
Spiro Compound Formation. III. The Formation of Spiro Compounds by the Rearrangement of Bicyclo[5.4.0]-undecene(1,7) and Cyclopentylcyclohexene
Authors: Nojima Masatomo , Tokura Niichiro 
Published: July 2006

Abstract
The isomerizations of bicyclo[5.4.0]undecene-(1,7) (IV), spiro[5.5]undecene-1 (V), and 1-cyclopentylcyclohexene (VI) were examined with equivalent amounts of perchloric acid in acetic acid or in ethanol at 75°C. In acetic acid, IV, V, and VI all rearranged to form spiro[5.5]-undecan-1-yl acetate (VII) and spiro[5.5]undecan-2-yl acetate (VIII), together with the three olefins IV, V, and VI. No rearranged product has been obtained by the same procedure in ethanol.
Effect of Pressure on Graphitization of Carbon. VI. Normal Pressure Heat Treatment of Soft Carbon Pre-Heat-Treated under High Pressure
Authors: Kamiya Kan-ichi , Inagaki Michio , Saito Hajime 
Published: July 2006

Abstract
Three different samples of polyvinylchloride coke (designated as N-1, N-2, and N-3 which were pre-heat-treated at 1470, 1590, and 1620°C, respectively, under 5 kbar) were heat-treated in a flow of nitrogen under normal pressure. Process of graphitization in these samples was investigated by analyzing (004) diffraction profile. Sample N-1 has a symmetrical profile and consists only of the trubostratic component As. Samples N-2 and N-3 have a composite profile and are composed of the turbostratic component As and the graphitic component Gs. Only the profiles corresponding to the turbostratic component As of these samples shift gradually to higher angle together with sharpening when the heat treatment temperature under normal pressure increases. Changes in c0-spacing and crystallite size Lc of the component As with heat treatment temperature follow the same course of change as in those of the original polyvinylchloride coke. However, heat treatment of the sample under normal pressure did not affect the quality and quantity of the component Gs which had been formed by the pre-heat-treatment under high pressure. These results indicate that the pre-heat-treatment of soft carbon under high pressure has no accelerating effect on the graphitization of the carbon in the subsequent heat treatment under normal pressure.
Moderator Effects on the Reactions of 82Br Activated by the Isomeric Transition with Gaseous Methyl Bromide
Authors: Okamoto Jiro , Tachikawa Enzo 
Published: July 2006

Abstract
82Br obtained via the (I. T.) process has been reacted with methyl bromide. In the gaseous phase, only CH382Br and CH282BrBr are observed as major products, whereas in the solid phase other products, such as CH82BrBr2 and C2H582Br, have also been observed. Moderator experiments using He or Xe indicate that the formations of both CH382Br and CH282BrBr involve the reactions of the energetic 82Br atom. This is in great contrast to the early observations of the Br2-CH4 system, where the ionic as well as the energetic reactions of 82Br play a role in the formation of the C-82Br bond. Comparisons of these results with those found in the reactions of the 80Br obtained via the (n, γ) process suggest that the Br atom obtained via the (n, γ) process is more electronically excited than that from the (I. T.) process. The kinetic analysis of the present results gives the following relative α-values: αHe, 1.0; αXe, 8.8; αCH3Br, 10.3. It is suggested that, during the cooling-down process of 82Br, a high inelasticity is involved in the collision of 82Br, even with monatomic molecules.
Measurement of Negative Ions Formed by Electron Impact. III. The Ionization Efficiency Curves of Negative Ions of m⁄e 26 and 42 from Nitroalkanes
Authors: Tsuda Satoru , Yokohata Akira , Kawai Michihiro 
Published: July 2006

Abstract
The studies of this series were extended to the negative ions of m⁄e 26 and 42 obtained from nitroalkanes; nitromethane, nitroethane, 1-nitropropane, and 2-nitropropane. For m⁄e 26 (probably, CN−) ions, the contribution of three or two processes in the range from zero to ∼20 eV of electron energy was observed for nitromethane or other samples. On the basis of ΔHf values of the reactants and products, and of the value of EA(CN), the plausible reactions to be assigned to each process were presented. For the first process, CH3NO2+e−→CN−+H2O+OH, RNO2+e−→CN−+R1OH+OH. For the second process, CH3NO2+e−→CN−+H2O+O+H, CH3NO2+e−→CN−+H2+O2+H, RNO2+e−→CN−+R1+HO2+H, and C3H7NO2+e→CN−+C2H4+H2+O+OH irrespective of kind of nitropropane. For the third process, CH3NO2+e−→CN−+3H+O2. For m⁄e 42 (probably, CNO−) ions, the contribution of two processes was observed. By taking ΔHf (CNO)=x (eV), EA(CNO)=y (eV), and also combining the observed onset values with the calculated values of appearance potential of reactions to be assigned for each process — for the first process, CH3NO2+e→CNO−+H2+OH, RNO2+e−→CNO−+R1OH+H; for the second process, CH3NO2+e−→CNO−+HO+2H, CH3NO2+e−→CNO−+H2+O+H, RNO2+e−→CNO−+R1O+2H– a relation of x−y\simeq2(eV) was derived.
Chromium(III) Complexes with N,N′-Ethylenediaminediacetic Acid
Authors: Fujii Yuki , Kyuno Eishin , Tsuchiya Ryokichi 
Published: July 2006

Abstract
The following chromium(III) complexes containing N,N′-ethylenediaminediacetic acid (EDDA) were newly prepared: [Cr(Hedda)2]Cl·3H2O (red) (I), [Cr2(OH)2(edda)2]·6H2O (purple) (II), H[Cr(edda)(ox)]·2H2O (purple) (III), [Cr(edda)(dip)]I·5H2O (orange) (IV), K[Cr(NCS)2(edda)]·H2O (reddish purple) (V) and [Cr(Cl)(edda)(H2O)]·3H2O (bluish purple) (VI), where edda, ox and dip are the abbreviations of the N,N′-ethylenediaminediacetate and oxalate anions, and α,α′-dipyridyl respectively. On the basis of the experimental results, it was concluded that EDDA is coordinated as a terdentate ligand in complex I and as a quadridentate in the other complexes prepared in the present work. Furthermore, it was also suggested that complex II has a dimer structure and complex V has trans configuration (with respect to the coordinated carboxylate oxygen).
The Kinetics of Substitution Reactions Involving Metal Complexes. XIII. Reactions of Zinc(II) with meso-Butylenediaminetetraacetatocobaltatet(II) and with Propylenediaminetetraacetatocobaltate(II)
Authors: Ogino Hiroshi , Baba Toshiyuki , Tanaka Nobuyuki 
Published: July 2006

Abstract
Kinetics of the substitution reactions of zinc(II) with meso-butylenediaminetetraacetatocobaltate(II) (cobalt(II)-meso-BDTA) and propylenediaminetetraacetatocobaltate(II) (cobalt(II)-PDTA) have been studied. The reaction of zinc(II) with cobalt(II)-meso-BDTA complex proceeds through two simultaneous reaction paths involving the acid dissociation reactions of the cobalt(II) complex. On the other hand, the reaction of zinc(II) with cobalt(II)-PDTA proceeds through four simultaneous reaction paths, of which two involve electrophilic substitution reactions and the others, the acid dissociation reactions of the cobalt(II) complex. This kinetic behavior is discussed on the basis of the natures of the ligands.
Anionic Copolymerization of Isoprene and 1,1-Diphenylethylene
Authors: Yuki Heimei , Okamoto Yoshio 
Published: July 2006

Abstract
Anionic copolymerization of isoprene (M1) and 1,1-diphenylethylene (M2) was carried out in tetrahydrofuran (THF), dioxane, benzene, and n-heptane by using n-butyllithium (n-BuLi), Na-naphthalene, Na- and K-dispersions as initiators. An alternating copolymer was obtained in the copolymerization in THF, which proceeded without a chain transfer and a termination. Monomer reactivity ratios, r1 obtained by assuming the rate constant k22=0, were 0.12 (Li+), 0.11 (Na+), and 0.11 (K+) in THF at 0°C. The r1 value in benzene at 40°C, however, was affected by the counter ion as follows: 37 (Li+), 0.38 (Na+), and 0.05 (K+). With Li+ counter ion the values were 0.50 in dioxane at 30°C and 29 in n-heptane at 40°C. The order of rate constants in the copolymerization in THF with n-BuLi at 0°C, was k12&gt;k11&gt;k21, the last of which was 2.64×10−3l/mol sec.
Synthetic Studies of the Flavone Derivatives. IX. The Syntheses of Axillarin and Its Related Compounds
Authors: Fukui Kenji , Nakayama Mitsuru , Horie Tokunaru 
Published: July 2006

Abstract
By using the method of Allan-Robinson’s flavone synthesis, the condensation of 3,ω-dimethoxy-2,1,6-trihydroxyacetophenone with 3,4-dibenzyloxybenzoic anhydride gave a mixture of 3,6- and 3,8-dimethoxy-3′,4′-dibenzyloxy-5,7-dihydroxyflavone (X and XI). The catalytic debenzylation of the above flavones then gave axillarin (I) and 3,8-dimethoxy-5,7,3′,4′-tetra-hydroxyflavone (IV) respectively. Axillarin 7-O-methyl ether(III) was prepared by the partial methylation of X, followed by catalytic debenzylation.
Solvent Effect under High Pressure. III. The Application of the Electrostriction Model to the Activation Entropy
Authors: Kondo Yasuhiko , Tokura Niichiro 
Published: July 2006

Abstract
The expression which relates the activation entropies of the reactions measured in various solvents with the products of the coefficients of thermal expansion and the molar volumes of the respective solvents has been derived based on the concepts of the electrostriction theory. For three Menschutkin reactions and one acylation reaction linear correlations to be expected from the above expression have been found between the activation entropies and the products of the coefficients of thermal expansion and the molar volumes of the solvents. Moreover, the interrelation between the activation volumes and the activation entropies has been discussed based on this model.
Phosphorus-proton Spin-spin Coupling in the P–O–C–H Group. A Comparison of Cyclic and Acyclic Systems
Authors: Kainosho Masatsune , Nakamura Asao , Tsuboi Masamichi 
Published: July 2006

Abstract
Proton magnetic resonance spectra for eleven compounds with the POCH system have been examined. They are three 4-phenyl-2,2-disubstituted(X,Y)-1,3,2-dioxaphosphorinanes where X=Cl, Y=O (I); X=Cl, Y=S (II); and X=O−K+, Y=O (III); four 5,5-dimethyl-2,2-disubstituted (X,Y)-1,3,2-dioxaphosphorinanes where X=Cl, Y=O (IV); X=Br, Y=O (V); X=Cl, Y=S (VI); and X=OH, Y=O (VII); and four dimethyl phosphates, Y=P(-X)-(-OCH3)2, where X=Cl, Y=O (VIII); X=Br, Y=O (IX); X=Cl, Y=S(X); and X=O−\frac12Ba2+, Y=O (XI). It has been found that the 1,3,2-dioxaphosphorinane ring in each of I–VIII is virtually fixed in a chair form in the solution, and there is no appreciable ring inversion as confirmed by NMR spectra. The phosphorus-proton coupling constant of the POCH system with the gauche relation (Jg) and that with the trans relation (Jt) were determined in each of these compounds (I–VII). The \frac23Jg+\frac13Jt values calculated from the determined Jg and Jt values are always smaller than the \frac23Jg+\frac13Jt values observed for the corresponding acyclic compounds (VIII–XI). This difference was explained in terms of a slight flattening of 1,3,2-dioxaphosphorinane ring from the ideal chair conformation.
Effect of Coexisting Minerals on Graphitization of Carbon under Pressure. III. Accelerating Effect of Calcium Hydroxide
Authors: Noda Tokiti , Inagaki Michio , Hirano Shin-ichi , Saito Hajime 
Published: July 2006

Abstract
The polyvinyl chloride coke was heat-treated under the pressure of 3.2 kbar at 600–850°C for 20–240 min in a simple piston-cylinder type vessel, being sandwiched between two disks of calcium hydroxide. By electron microscopic observations, particles having the six-fold symmetry diffraction pattern of graphite single crystal were found besides particles of amorphous carbon even in the specimen heat-treated at temperature as low as 600°C. Above 800°C, the sharp peak corresponding to the graphitic component appeared on (002) diffraction profiles, overlapping with the broad band of the turbostratic component. The formation of the graphitic component seems to be related to the recrystallization of coexisting calcium hydroxide, as in the case of limestone and calcium carbonate. However, the fact that a small amount of free calcium oxide formed by the decomposition of calcium hydroxide was detected in the heat-treated carbon specimens suggests a chemical theory for the accelerating effect of calcium compounds on the graphitization of carbon under pressure.
Derivatographic Studies on Transition Metal Complexes. II. Thermal Reaction in the Solid State of Chromium(III) and Cobalt(III) Aquo-EDTA-like Complexes
Authors: Tsuchiya Ryokichi , Uehara Akira , Kyuno Eishin 
Published: July 2006

Abstract
The thermal reaction processes in the solid state of the following chromium(III) and cobalt(III) aquo complexes with EDTA or the related aminopolycarboxylic acids were investigated by means of derivatography: [CrHedta(H2O)] (I), [CrHpdta(H2O)]·H2O (II), [CrHtmta(H2O)]·H2O (III), [Cr(OH)Hapda(H2O)2] (IV) and [Co(OH)Hapda(H2O)2] (V) (edta, pdta, tmta and apda are the abbreviated forms of ethylenediaminetetraacetate, propylenediaminetetraacetate, trimethylenediaminetetraacetate and ammoniapropionicdiacetate anions, respectively.). With complex I, the carboxylate anion free from coordination to metal coordinated when the dehydration took place at ca. 280°C. It resulted in the change of the coordination number of EDTA from quinquedentate to sexadentate. In the case of complexes II and III, the transition appeared below ca. 100°C where the coordinated water molecule in the coordination sphere is thermally expelled to the outer sphere as the protonated form due to the coordination of a carboxylate anion. PDTA and TMTA (conjugated acids of pdta and tmta respectively) also changed from quinquedentate to sexadentate ligands in this step. Of complexes IV and V, the coordinated hydroxo group was excluded as a water molecule together with the hydrogen in a free carboxylate anion at ca. 140°C to make the coordination number of APDA(conjugated acid of apda) change from terdentate to quadridentate. The activation energies and the enthalpy changes in each thermal reaction process were determined by the analysis of their derivatograms.
Synthesis of Albonoursin
Authors: Shin Chung-gi , Chigira Yasuhiro , Masaki Mitsuo , Ohta Masaki 
Published: July 2006

Abstract
Treatment of the ester of 2-(2-chloroacetamido)-2-alkenoic acid with ammonia led to the formation of 3-alkylidene-2,5-piperazinedione. By using this method, total synthesis of albonoursin was accomplished. 2-(2-Chloroacetamido)-4-methyl-2-pentenoic acid, derived from the condensation of 4-methyl-2-oxopentanoic acid with chloroacetonitrile or the pyrolysis of 2,2-bis(2-chloroacetamido)-4-methylpentanoic acid, was converted to the ethyl ester, which was treated with ammonia to give 3-isobutylidene-2,5-piperazinedione. The piperazinedione was also synthesized by the esterification of 2-(2-aminoacetamido)-4-methylpentenoic acid, followed by a cyclization of the ester. Condensation of the piperazinedione with benzaldehyde yielded 3-benzylidene-6-isobutylidene-2,5-piperazinedione, and its physical constants are virtually identical with those recorded for the natural albonoursin.
Kinetic Study of the Polymerization of Diallyl Carbonate
Authors: Matsumoto Akira , Takashima Katsutoshi , Oiwa Masayoshi 
Published: July 2006

Abstract
The polymerization of diallyl carbonate was carried out at 60°C, benzoyl peroxide being used as the initiator; here it has been discussed kinetically from the point of view of cyclopolymerization. The rate of polymerization, Rp, was not proportional to the square root or the first power of the initiator concentration, (I), but Rp/(I)1⁄2 and (I)1⁄2 bore a linear relationship. The rate of polymerization, the residual unsaturation, and the degree of polymerization decreased with a decrease in the monomer concentration. The relation between the rate of polymerization over the degree of polymerization, Rp/\barPn,o and the monomer concentration, (M), was also linear, as in Rp/(I)1⁄2 and (I)1⁄2. The ratio of the rate constant of the unimolecular cyclization reaction to that of the bimolecular propagation reaction of the uncyclized radical, Kc, was estimated to be 4.0 mol/l from the dependence of the residual unsaturation on the monomer concentration.
The Reaction of Carboxylic Acids and Hydrocarbons in a Silent Electric Discharge. I. The Reaction of Acetic Acid with Ethylene
Authors: Hiraki Teruo 
Published: July 2006

Abstract
In order to ascertain the possibility of telomerization by a silent discharge, a mixture of acetic acid and ethylene was discharged in an ozonizer under various conditions. The α-C-alkylation of acetic acid which was expected to result from its discharge-induced reaction with ethylene was not observed; neither propionic acid nor higher carboxylic acids were identified by gas chromatography. However, n-butyl acetate was obtained in a good yield. The formation of the acetate can be explained as resulting from the combination of an acetoxy radical with two molecules of ethylene. The yield of the acetate, as well as those of the liquid and gaseous products, increased with a rise in the temperature and in the voltage, with the time, and with a rise in the ratio of ethylene to the acid concentration. Besides this acetate, the liquid products were confirmed to consist of ethyl methyl ketone, acetone, acetaldehyde, hydrocarbons, and ethyl and n-propyl acetates. The gaseous products were carbon dioxide, carbon monoxide, C1–C4-hydrocarbons, and hydrogen. Judging from the relative concentration of each compound in the reaction products, it may be said that the acetoxy radical (CH3COO·) and the acetyl radical (CH3CO·) are the main intermediates in this reaction system.
Studies of the Organic Reactions of Metal Carbonyls. XVII. The Reaction of Potassium Iron Carbonylates with Allyl Halide and Its Derivatives
Authors: Takegami Yoshinobu , Watanabe Yoshihisa , Mitsudo Takeaki , Okajima Toshiharu 
Published: July 2006

Abstract
The reactions of potassium iron carbonylates (K2Fe(CO)4, KHFe(CO)4 and K2Fe2(CO)8) with allyl halide and its derivatives have been studied. Allyl halide and its derivatives react readily with these carbonylates in ethyl alcohol at 30°C to give the corresponding and isomerized olefins. The reaction of allyl chloride in hydrous ethyl alcohol gives propylene in a good yield and 1,5-hexadiene as a by-product. In dry ethyl alcohol, the yield of propylene decreases. The reaction of trans-1-chloro-2-butene gives trans-2-butene (the major product), cis-2-butene, and 1-butene. The reaction of 1-chloro-3-methyl-2-butene and 3-chloro-3-methyl-1-butene gives 2-methyl-2-butene (the major product), 3-methyl-1-butene, and 2-methyl-1-butene. These reactions are considered to proceed via σ- and π-allyl iron carbonyl complexes.
Organic Reactions under High Pressure. IV. Effect of Pressure on the Competitive Nitration of Benzene and Monosubstituted Benzenes. Dependence of the Substitutent Effect on the Pressure
Authors: Asano Tsutomu 
Published: July 2006

Abstract
Partial rate factors for the nitration of six monosubstituted benzenes with nitric-sulfuric acid in acetic acid at 45°C have been determined over the 1–2000 kg/cm2 pressure range. The ρ value for this reaction changed from −7.22 (1 kg/cm2) to −6.92 (2000 kg/cm2). This pressure dependency of the ρ value was not expected for this type of reaction. This phenomenon is interpreted in terms of the dependence of the degree of solvation of the transition states on the substituents. An abnormal deactivation due to pressure has been observed in the case of biphenyl. This deactivation has been attributed to an increase in the deviation from the coplanarity of the two phenyl groups. The dependence of the ortho: para ratios on the pressure is also discussed.
Studies of the Organic Reactions of Metal Carbonyls. XVI. Solvent Effects on the Hydroformylation of Propylene and on the Reaction of Cobalt Hydrocarbonyl with 1-Pentene
Authors: Takegami Yoshinobu , Watanabe Yoshihisa , Masada Hiromitsu , Mitsudo Takeaki 
Published: July 2006

Abstract
In the reaction of cobalt hydrocarbonyl with 1-pentene at 10°C, solvents have a great effect on the distribution of the products, caproylcobalt carbonyl (I) and α-methylvalerylcobalt carbonyl (II). The I-to-II ratio is 72 : 28 in toluene, in toluene-dioxane (1 : 1 in volume), and in tolueneethyl acetate. The percentage of II increases to 40–66% in toluene-diethyl ether, -tetrahydrofuran, -acetone, -ethyl alcohol, and -acetonitrile. In the hydroformylation of propylene, the distribution of the products, n- and isobutyraldehyde, is also affected by the solvents. In toluene, the n-to-iso ratio is about 75 : 25, while in dioxane and in butyl acetate the percentage of the n-aldehyde increases to 79–83%. In methyl alcohol, dimethyl acetals of the aldehydes and n- and isobutyrate are formed. The n-to-iso ratio is the highest in the esters (3.2–8.5), followed by the acetals (0.7–1.6) and the aldehydes (0.4).
Raman and Infrared Spectra of β-Alanine
Authors: Krishnan R S , Katiyar R S 
Published: July 2006

Abstract
The Raman spectrum of β-alanine has been recorded in the single crystal form employing λ 2537 technique. The infrared spectra in Nujol mull and KBr pellet have been taken for the range 400–4000 cm−1. The spectra exhibit the characteristic lines of the zwitter ion and also hydrogen bond vibrations in the region 2400–3000 cm−1. The tentative assignments of the observed lines are given and compared with those of other amino acids.
Theory of the Gel-forming Polymerization of Polyepoxy and Related Compounds
Authors: Yamabe Tokio , Fukui Kenichi 
Published: July 2006

Abstract
A theory of the molecular-size distribution of cross-linked polymers to be formed from a mixture of polyfunctional monomers and mono-functional monomers through step-by-step polymerizations by certain initiators is presented on the assumption that all unconverted functional groups are equireactive for both initiations and propagations, which proceed without termination, transfer, or cyclization. The distribution is obtained by applying the statistical theory of gel formation with multifunctional interunit junctions, which are, in this case, equivalent to cross-linking chains. Some noticeable theoretical results are obtained: (1) the distribution obtained is quite different from that obtained for branched-chain polymers by condensation polymerization; (2) the fraction of converted functional groups at the gel point is independent of the initial concentration of the monofunctional monomer, while it is in proportion to the ratio of the initial concentration of the initiator to that of polyfunctional monomers; (3) there is a certain condition under which the gelation will never take place, even at complete conversion, and (4) the state to be reached after the gel point is quite different from the results obtained previously. The case of a mixture of monomers with any distribution of functionalities is also briefly presented. An explanation of the validity of the distribution beyond the gel point is discussed in the Appendix.