bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal Structure of Bis(iminodiacetamide)copper(II) Perchlorate
Authors: Sekizaki Masao
Published: July 2006

Bis(iminodiacetamide)copper(II) perchlorate was newly synthesized, and the crystal structure was determined from three-dimensional X-ray data collected on a diffractometer. The structure was refined by blockdiagonal least-squares methods to give R=0.08 for the 950 observed reflections. The crystals are monoclinic with the space group of P21/c. There are two formula units per unit cell with a=6.183, b=17.617, c=8.900 Å, and β=110.2°. The complex is centrosymmetric, in which the two ligand molecules coordinate to the central copper atom through two imino nitrogen atoms and two of the four amide oxygen atoms in trans positions, exhibiting a square-planar coordination. The other two amide oxygen atoms are weakly bonded to the copper atom above and below this square-plane, thus completing an s-facial distorted (elongated) octahedral coordination. The complex cations are held together through hydrogen bonds to form infinite chains along the a axis. These chains are connected with one another by perchlorate ions through hydrogen bonds, thus forming three-dimensional networks.
The Reaction of N-Chlorocarbamoylethyl Starch with Amines in an Aqueous Alkaline Medium; Reactions of An Isocyanate Group
Authors: Higuchi Mitsuo , Takeshita Kenji , Senju Ryoichi
Published: July 2006

The reactions of N-chlorocarbamoylethyl starch with simple monoamines were investigated in order to elucidate the mechanism of the reaction of an isocyanate group with amines in an aqueous alkaline medium. It was confirmed that the N-chloroamide group reacts with amines through the formation of an isocyanate group. The reactions of the isocyanate with amines in the presence of sodium hydroxide obeyed the following equation: (rate of isocyanate–amine reaction)/(rate of isocyanate–OH− reaction)=ku[amine]/ka[OH−] showing no catalytic effects of reactants or products. The reactivities of most of the primary amino groups attached to primary carbon with the isocyanate are comparable to that of the hydroxide ion. The relative rates of the reactions of amines with the isocyanate are not always correlated to their basicities, even when differences in steric hindrance are not great. Both the enthalpy and entropy of activation for the isocyanate–amine reactions are smaller than those for the isocyanate–OH− reaction.
A Mechanistic Study of the Acetolyses of 3-Chloropropene Sulfide and 2-Chloroethyl Methyl Sulfide
Authors: Tabushi Iwao , Tamaru Yoshinao , Yoshida Zen-ichi
Published: July 2006

Forming a marked contrast to hydrolysis, the first-order rate constant in the acetolyses of 3-chloropropene sulfide (I) and 2-chloroethyl methyl sulfide (II) has been observed to be seriously decreased; this may be ascribed to the return to the starting material of the sulfonium intermediate (III′ or IV) by the chloride ion liberated in the course of the reaction. The reaction has substantially obeyed first-order kinetics, giving exclusively and quantitatively skeletally-rearranged 3-acetoxy-thietane (the first-order rate constant; k1=2.1×10−5 s−1, at 55.0 °C) and 2-acetoxyethyl methyl sulfide (k1=4.8×10−4 s−1, at 55.0 °C) from I and II respectively.
A Polarographic Study of Aryl-substituted Tetra-aza- and Hexa-aza-pentalenes in Dimethylformamide
Authors: Matsumoto Akira , Lee Joung Hee , Yoshida Masayuki , Simamura Osamu
Published: July 2006

The polarographic reduction potentials of aryl-substituted 1,2,4,5-tetra-aza- and 1,2,3,4,5,6-hexa-aza-pen-talenes were shown to be approximately governed by the numbers of nitrogen atoms and aryl-substituents. Such effect of nitrogen atoms was discussed in terms of the orbital energies of parent azapentalenes obtained by HMO calculations.
Preparations and Properties of 5-Phenyl-5H[1,2,3]-triazolo[4,5-c][1,2,5]-oxadiazole, -thiadiazole, and -selenadiazole
Authors: Matsumoto Akira , Yoshida Masayuki , Simamura Osamu
Published: July 2006

The title compounds have been synthesized, and their chemical reactivities and spectroscopic properties are discussed in comparison with those of 2,5-diphenyl-v-triazolo[4,5-d]-v-triazole.
Reactions of Iodocarbenoid of Zinc. II. The Iodocyclopropanation of Olefins with Diethylzinc and Iodoform
Authors: Miyano Sotaro , Hashimoto Harukichi
Published: July 2006

The iodocyclopropanation of olefins by the iodocarbenoid of zinc generated from diethylzinc and iodoform was investigated. When the reaction was carried out in a neat olefin, cyclohexene, 1-hexene, cis-2-butene, isobutene, and styrene gave the corresponding iodocyclopropanes in yields of 70, 34, 63, 55, and 44% respectively, showing that the CHI3–Et2Zn system is a convenient route for iodocyclopropanes. The reaction with cyclohexene was investigated in some detail. syn-7-Iodonorcarane easily gave 3-ethylcycloheptene upon treatment with diethyl zinc in the presence of zinc iodide.
Synthetic Study of Colchicine
Authors: Kato Michiharu , Kido Fusao , Wu Ming-Der , Yoshikoshi Akira
Published: July 2006

An efficient route based upon solvolytic fragmentation of a cyclopentadiene-dichloroketene adduct 4c has been investigated for the synthesis of trimethoxyphenylpropyltropolone 2b, a synthetic intermediate of colchicine 1a. Attempted synthesis of the corresponding unsaturated tropolones 8a and 10 is also discussed.
Synthesis of Sesquirosefuran
Authors: Kumazawa Satoru , Nishihara Koichi , Kato Tadahiro , Kitahara Yoshio , Komae Hisashi , Hayashi Nanao
Published: July 2006

Sesquirosefuran (I) was synthesized by the coupling of geranyl bromide with 2,2′-bis(3-methylfuryl)-mercury in 29% yield.
The Direct-current Conductivity of Silica Gel
Authors: Muroya Masa-aki , Kondo Seiichi
Published: July 2006

The study of the effect of heat-treatment on the direct-current conductivity of silica gel showed that the conductivity changed in response to the dehydration of the adsorbed water and of various kind of silanols. The temperatures of dehydration by this experiment seems to coincide with other experiments such as IR spectroscopy.
Solid Complex Formation of Malonic Acid with Glycine
Authors: Nishijo Jujiro
Published: July 2006

A solid complex in a molar ratio of 1 : 1 was inferred to be formed by means of an intermolecular hydrogen bond between the hydrogen atom of the –COOH of malonic acid and the –COO of glycine.
The ESR Spectra of Michler’s Ketone Anion Radicals
Authors: Fujita Hideo , Kako Saburo , Yamauchi Jun , Ohya-Nishiguchi Hiroaki , Deguchi Yasuo
Published: July 2006

The ESR spectra of Michler’s ketone anion radicals reduced by alkali metal in solution consist of five groups of lines at +20 °C, but change into three groups of lines at −50 °C. The assigned hyperfine splitting constants are AHo=3.22, AHm=0.43, AN=0.72, AHCH3=0.29 gauss at +20 °C.
Solvolytic Reactions in Dipolar Aprotic Solvents. Reaction Rates of the Tertiary Aralkyl System
Authors: Uchida Takane , Marui Sumie , Miyagi Yo , Maruyama Kazuhiro
Published: July 2006

Solvolytic reaction rates of 2-aryl-2-chloropropanes in dipolar aprotic solvents were determined in order to obtain activation parameters, ρ-values, and β-deuterium effect. The results are compared with those in protic solvents.
Determination of Enantiomeric Purity of 1-Phenylalkanols Using a Chiral NMR Shift Reagent
Authors: Yamamoto Keiji , Hayashi Tamio , Kumada Makoto
Published: July 2006

Addition of tris[3-(trifluoromethylhydroxymethylene)-d-camphorato]europium(III) to solutions of partly active (S)-1-phenylalkanols caused large enantiomeric shift differences (ΔΔδ) in their 1H NMR spectra, which permitted a direct determination of enantiomeric compositions of these alkanols.
Calculation of the Carbon-13 NMR Chemical Shifts of Linear and Branched Paraffins and Saturated Cyclic Hydrocarbons
Authors: Takaishi Kitsuma , Ando Isao , Kondo Masahiro , Chûjô Riichirô , Nishioka Atsuo
Published: July 2006

The carbon-13 NMR chemical shifts of linear and branched paraffins have been calculated by means of Pople’s theory, particularly using the averaged excitation energy method. The calculation was carried out based on the CNDO/2 molecular orbital method. The values calculated by means of the averaged excitation energy method deviate extremely from the experimental ones; therefore, the energies most suitable for giving good agreement are investigated and determined for linear and branched paraffins. The suitable energies are expressed by an empirical formula, correlated to the molecular structure. The results obtained may be briefly expressed by;

& ΔE= 11.30×1.015^a×0.958^b×1.010^c×S

& S=1.011^d×1.009^e×1.029^f×1.009^g×1.030^h×1.031^i

(see Results and Discussion for the notations used).

This empirical averaged excitation energy expression is applied to cyclic hydrocarbons, such as cyclohexane, methylcyclohexane, and dimethylcyclohexane. Further, the γ-effect is estimated on the basis of these results.
A New Pyrochlore System, Pb(Tix·Sn1–x)O3, and Its Transition to a Perovskite System
Authors: Shirasaki Shin-ichi , Yamamura Hiroshi , Muramatsu Kunitaka , Takahashi K\={o}ichiro
Published: July 2006

A series of pyrochlore compounds of Pb(Tix·Sn1–x)O3, was aqueously prepared. They were characterized in terms of inhomogeneously distributed Ti and Sn ions in the equivalent lattice positions. In the composition range where the value x was between 0.00 and 0.45, monophasic pyrochlore was crystallized. In the composition range of x\gtrsim0.45, however, the pyrochlore phase more or less coexisted with a noncrystalline substance whose composition was supposed to be Pb/(Ti+Sn) mole ratio <1.0. The process of thermal transition from the pyrochlore-type Pb(Ti0.4·Sn0.6)O3 to the perovskite-type system was traced by two lines of measurements of the pyrochlore, i.e., the lattice constant and the degree of fluctuation of interplanar spacings, and by measurements of the tetragonal lattice strain of the resultant perovskite. The results showed that the transition occurred preferentially at Ti-rich microregions in the matrix lattice, in which a measurable fluctuation of the Sn: Ti ratio was detected.
A Study of the Thermal Degradation of Several Halogen-containing Polymers by Torsional Braid Analysis
Authors: Furusho Noboru , Komatsu Tsuyoshi , Nakagawa Tsurutaro
Published: July 2006

The thermal degradation of several halogen-containing polymers in air was studied by means of the TBA(Torsional Braid Analysis) method and IR spectroscopy. The samples were poly(vinyl chloride)(PVC), vinylidene chloride-vinyl chloride copolymer(PVdC-VC), poly(vinyl fluoride)(PVF), poly(vinylidene fluoride)(PVdF), poly(vinyl bromide)(PVB), and poly (vinylidene bromide)(PVdB). The dynamic mechanical properties of these polymers are complicated at higher temperatures because of the thermal degradation, by, for example, dehydrohalogenation. The relative shear modulus (Gr) increases and then decreases through a maximum, accompanied by changes in the logarithmic decrement. The temperatures at which the changes in Gr occur become higher in the order of PVdB<PVB<PVdC-VC<PVC<PVdF<PVF. This order agrees with that of the bond energy in carbon-halogen bonds. The apparent activation energies of these reactions were obtained from the changes in Gr and from the relative absorbance ratio of the carbon-carbon double bond with time, respectively. In general, the values estimated by these two procedures agreed well in each case.
Studies on Reactions of the N-Phosphonium Salts of Pyridines. V. The Preparation of Carboxylic Amides and Esters by Means of the One-electron-transfer Oxidation of Phosphorous Acid and Its Esters in the Presence of Tertiary Amines
Authors: Yamazaki Noboru , Higashi Fukuji
Published: July 2006

The oxidation of phosphorous acid and its esters with an equimolar amount of mercurous chloride and half an equimolar amount of mercuric chloride was carried out in tertiary amines. On the treatment of the oxidation mixture with carboxylic acids, amines, and alcohols, followed by aminolysis, alcoholysis, or acidolysis, the corresponding carboxylic amides and esters were obtained in good yields, together with a nearly quantitative yield of metallic mercury. The yield was affected by the tertiary amines, the alkyl groups in the dialkyl phosphites, and the steric effect of the carboxylic acids. The reaction was proposed to proceed through the activation of carboxylic acids, amines, and alcohols via the N-phosphonium salts prepared by the oxidation. The electron-transfer processes involved in the oxidation were discussed on the basis of the yield of the amides obtained. These procedures were successfully extended to the preparation of peptides and active esters of amino acids, using diphenyl phosphite in pyridine.
Synthesis of Succin-as-eins
Authors: Gopal R , Gupta P C , Garg S P
Published: July 2006

A new series of compounds, succin-as-eins(SAE)–methyl phenol SAE, methyl resorcinol SAE, methyl catechol SAE, methyl quinol SAE, methyl phloroglucinol SAE, methyl pyrogallol SAE and methyl orcinol SAE have been prepared by condensing 2-acetyl propionic acid with appropriate phenols. The structure of methyl resorcinol SAE, based on chemical reactions and spectral data is discussed. The λmax values for few of the dyes are comparable with their analogous succineins and phthaleins.
Tritium Fractionation in the Crystallization of Aluminum Alums from Their Aqueous Solutions
Authors: Tanaka Haruhiko , Ando Hiroko , Negita Hisao
Published: July 2006

The tritium fractionation in the crystallization of NH4Al(SO4)2·12H2O from a solution was found to be larger than those in NaAl(SO4)2·12H2O and KAl(SO4)2·12H2O. This fact was discussed in terms of the proton exchange between NH4+ and H2O.
The Standard Free Energy of the Formation of LaFeO3 at 1204°C
Authors: Kimizuka Noboru , Katsura Takashi
Published: July 2006

The standard free energy of the formation of LaFeO3 was detemined to be −68700±200 cal·mol−1 at 1204°C by the following reaction: 1/2 La2O3(s)+Fe(s)+3/4 O2(g) = LaFeO3(s), based on precise phase equilibria in the Fe–Fe2O3–La2O3 system.
The Synthesis of Methylthio- and Bis(methylthio)phenazine Derivatives
Authors: Tada Masao
Published: July 2006

A number of methylthio- and bis(methylthio)phenazine derivatives have been prepared by the reactions of various halogenophenazines and their N-oxides with sodium methyl sulfide.
Dissociation Constants of 2-Aminotroponcs
Authors: Imafuku Kimiaki , Takata Yasuyoshi , Matsumura Hisashi
Published: July 2006

The dissociation constants of 2-aminotropones were measured in 50% aqueous methanol at 20°C and shown to be correlated by the Hammett equation with ρ=3.40. The difference between 4- and 6-substituents is discussed.
Decomposition of 1,4-Dimethoxybenzene Radical Cations in CH3NO2–AlCl3 System
Authors: Nishinaga Akira , Hayashi Hidetoshi , Matsuura Teruo
Published: July 2006

The decomposition of 1,4-dimethoxybenzene cation (2a) and 1,4-dimethoxy-2,5-dimethylbenzene cation (2b) gave 2,2′,5,5′-tetramethoxydiphenyl and 2,5-dimethyl-p-benzoquinone indicating that the reaction pathway depends on substituent at nucleus of the radical cations 2.
Carbon-13 Nuclear Magnetic Resonance Spectra of α-Ribonucleosides
Authors: Sugiyama Hiroshi , Yamaoka Naotaka , Shimizu Bunji , Ishido Yoshiharu , Seto Shuichi
Published: July 2006

The C-13 NMR spectra of four α- and two β-ribonucleosides have been measured and all carbon signals have been assigned.
The Heck Reaction of 2-Vinylpyridine
Authors: Kasahara Akira , Izumi Taeko , Takeda Toru , Imamura Hayao
Published: July 2006

In the presence of lithium chloropalladite, 2-vinylpyridine reacted with phenylmercuric chloride to give di-μ-chloro-bis[2-phenyl-2-(α-pyridyl)ethyl]dipalladium (II). Similar complexes were obtained from p-toy-, p-anisyl-, or m-nitrophenylmercuric chloride. The σ-bonded structures of these complexes have been confirmed by a study of their absorption and of the NMR spectra.
The Molar Volume and Entropy of Adsorbed Methane on Porasil
Authors: Hori Yoshio , Kobayashi Riki
Published: July 2006

With the use of high-precision gas-chromatography, the multilayer adsorption of methane on fused silica beads was precisely measured between 145.0 K and 213.6 K. The molar volume and the partial molar entropy of the adsorbed methane were determined as a function of the temperature. The molar volume in the monolayer region depends much less on the temperature than that of the bulk liquid. However, the molar volume of multilayer adsorbed methane shows a dependence on the temperature similar to that of bulk liquid, which is at a lower temperature. The volume of the monolayer is practically constant under the present experimental conditions. The apparent thickness of the adsorbed monolayer was interpreted in terms of a simple collision model. The partial molar entropy of the adsorbed phase is much lower than that of the saturated bulk liquid. The lower dependence of the molar volume on the temperature and the lower entropy suggest that the freedom of motion of the adsorbed molecules is restricted as compared with those in bulk liquid.
The Crystal Structure of (+)-2,5-Dimethoxy-8-Chloratriptycene
Authors: Kaneda Tsuguhiro , Sakabe Noriyoshi , Tanaka Jiro
Published: July 2006

The crystal structure of (+)-2,5-dimethoxy-8-chlorotriptycene has been investigated by the X-ray method. The crystal system is monoclinic, and the space group is P21. The cell dimensions are a=8.231, b=13.320, c=8.156 Å, and β=96.49°. The structure was deduced from the Patterson map and from the calculation of the R-factor minimized by varying the rotational and translational parameters. The structure parameters were refined by the block-diagonal least-squares method by using 1227 independent reflections; the final R-value was 0.073. The absolute configuration was determined to be 1R6S from the CuKα anomalous scattering of the chlorine atom.
Synthesis of Furfuryl and Nitrofurfuryl Derivatives of Adenine and Uracil
Authors: Fukatsu Shunzo , Sawa Aiko , Umezawa Sumio
Published: July 2006

Condensation of 5-nitrofurfuryl iodide with uracil in dimethylformamide in the presence of lithium hydride gave 1-(5′-nitrofurfuryl)uracil. When the iodide was treated with adenine, 3-substituted adenine was mainly obtained, whereas the analogous reaction of benzamidopurine gave 9-substituted adenine. These compounds showed antitumor and broad antibacterial activity. Furfuryl derivatives were also described.
Magnetic Properties of Nonbenzenoid Aromatic Hydrocarbons
Authors: Yamaguchi Hiroyuki , Nakajima Takeshi
Published: July 2006

The magnetic susceptibilities for nonbenzenoid aromatic hydrocarbons have been examined by using the modified London-Hoarau method in the framework of the Wheland-Mann-type SCF MO approximation. By taking into account the double-bond fixation quite common in these molecules, we obtained a general agreement between the calculated results and the available experimental values.
The Electronic Spectra of Paracyclophadiynes
Authors: Takabe Tetsuko , Tanaka Masashi , Tanaka Jiro
Published: July 2006

The electronic absorption spectra of [3,3]-paracyclophadiyne and [4,4]-paracyclophadiyne have been investigated in solution and in the crystalline state. A trans-annular interaction between the diacetylene group and the benzene ring has been found, and a theoretical study has been made to confirm the assignment. The bathochromic shift and the CT band from the benzene ring to the diacetylene group are particularly noticeable for [3,3]-paracyclophadiyne, where the inter-group distance is significantly shorter than the normal van der Waals distance.
N-Alkylideneanilines. III. Behavior of N-Isopropylideneanilines in Methanol-d4
Authors: Iwamura Hiizu , Tsuchimoto Michiko , Nishimura Shigeo
Published: July 2006

When N-isopropylideneanilines are dissolved in methanol-d4, three types of reactions, exchange of protons in isopropylidene moiety, formation of carbinolamine ethers, and liberation of anilines with formation of acetone dimethyl acetal take place as revealed by NMR spectra of the solutions. The H–D exchange reaction is favored by electron-releasing ring substituents and yet is considerably slower than the rates of the E–Z isomerization of the corresponding imines. The carbinolamine ethers are formed when the substituents are strongly electronegative. Formation of acetone dimethyl acetal occurs additionally with imines carrying halogen atoms as the ring substituents. The competitive reaction mechanism is proposed.
The Telomerization of Methyl Acetate and Methyl Cyanoacetate with Ethylene
Authors: Fujimoto Tsutomu , Hirao Ichiro
Published: July 2006

The telomerization of methyl acetate and cyanoacetate with ethylene initiated by di-tert-butyl peroxide was investigated. Methyl esters of linear and α-branched alkanoic acids, and linear and α-branched alkyl acetates, as well as hydrocarbons, were identified in the system of methyl acetate. The methyl esters of linear and α-branched α-cyanoalkanoic acids were identified in the system of methyl cyanoacetate, but no alkyl cyanoacetates could be found. It was suggested that intramolecular 1,5-hydrogen transfer in telomer radicals with two ethylene units and a chain-transfer reaction to the telomers gave the branched telomers. The chain-transfer constants were estimated in the system of methyl cyanoacetate. The introduction of the cyano group to methyl acetate at the α-position gave a favorable system for chain-transfer reactions and facilitated intramolecular 1,5-hydrogen transfer in the telomer radicals. The relatively higher relative reactivity of the methoxy group to the acetyl group in methyl acetate in the telomerization with ethylene was discussed.
Studies of Tritylated Sucroses. III. NMR Studies of Tritylacetylsucroses
Authors: Otake Toshiki
Published: July 2006

Seven tritylated derivatives have been synthesized by the tritylation of the primary hydroxyl group of sucrose. The 1H NMR spectra of their peracetyl derivatives have been determined at 100 MHz and 220 MHz in order to assign the sugar-ring-proton signals with the aid of the double-resonance technique and NMR spin simulation. The relationship between the chemical shifts of their methine protons and the substituted position of the bonded trityl groups is discussed. Crystalline 1′-mono-O-tritylsucrose derived from 6,6′-di-O-palmitolysucrose is also described.
Catalytic Hydration of Pyridinecarbonitriles in the Presence of [Cu(en)2]Cl2·2H2O and CuCl2·2H2O
Authors: Watanabe Ken-ichi , Murayama Kiyoshi
Published: July 2006

Spectrophotometric studies on the catalytic hydration of 2-pyridinecarbonitrile derivatives in the presence of [Cu(en)2]Cl2·2H2O and CuCl2·2H2O under nearly neutral conditions revealed that the products are their amides. In some cases, the yields were calculated from the weight of amides obtained. The hydration of the nitrile group was influenced by electronic and steric effects. Selective hydration of the nitrile group in α-position was observed in the case of dinitrile. The selectivity was applied to hydrolysis of nitriles to carboxylic acids.
Attempted Synthesis of Diphenylmethylenecyclobutanetrione and the Anomalous Behavior of Its Monoacetal, 4,4-Dimethoxy-2-diphenylmethylenecyclobutane-l,3-dione
Authors: Toda Fumio , Yuwami Koji
Published: July 2006

Neither the oxidation of 2-diphenylmethylenecyclobutane-1,3-dione (I) with SeO2 nor the hydrolysis of 4,4-dibromo- (III) and 4,4-dimethoxy-2-diphenylmethylenecyclobutane-1,3-dione (IV) afforded the title cyclobutanetrione (II). The title acetal (IV) was dissolved in coned HCl-MeOH without hydrolysis, probably in the protonated form (X) on its carbonyl oxygen. The basification of a solution of IV in coned HCl–MeOH-d4 recovered the IV undeuterated. On the other hand, IV was dissolved in KOH-MeOH in the form of the enolate anion (XII). The acidification of a solution of IV in KOH–MeOH-d4 afforded the deuterated acetal (IV-d6).
Telomerization of Ethylene with Chloroform Initiated by N-Chloroalkylamines
Authors: Asahara Teruzo , Sen\={o} Manabu , Ohtani Noritaka
Published: July 2006

N-Chloroalkylamines initiate the telomerization of ethylene with chloroform to give α,α,α-trichloroalkanes CCl3(C2H4)nH(I), which are the same products as those obtained by peroxide-initiated reactions. The N-chloro-alkylamine–iron and N-chloroalkylamine–ferrous chloride systems also initiate the reaction of ethylene with chloroform to afford α,α,ω-trichloroalkanes CHCl2(C2H4)nCl (II) as the main product, and a small amount of I along with other teJomers. The rate of the reaction and the composition of the products vary widely with the kind of N-chloroalkylamine. The reaction mechanism was discussed, a “caged radical” mechanism being proposed for the N-chloroalkylamine-ferrous chloride system.
Oxidation of Chromium(II) Complexes. I. Kinetics of the Oxidation of Tris(2,2′-bipyridine)- and of Tris(1,10-phenanthroline)chromium(II) Complexes with Hexaamminecobalt(III) Ion
Authors: Narusawa Yoshio , Kimura Masao , Nakano Kunio
Published: July 2006

Kinetic studies have been carried out on the oxidation of [Cr(bipy)3]2+ and [Cr(phen)3]2+ with [Co(NH3)6]3+(bipy and phen denote 2,2′-bipyridine and 1,10-phenanthroline, respectively). The rate law is found to be −d[Cr(II)]/dt=k1[Co(III)][Cr(II)]+k2[Cr(II)]. Simulation procedures with an analogue computer were applied for the analysis of these reactions. The rate constant k1 (direct oxidation) and k2 (dissociation) for [Cr(bipy)3]2+ were 180 M−1 s−1 and 0.120 s−1 (μ=0.11 with NaCl, at 25 °C) and those for [Cr(phen)3]2+ were 310 M−1 s−1 and 0.630 s−1 (μ=0.20 with NaCl, at 25 °C), respectively. The larger value of k1 for [Cr(phen)3]2+ as compared with that of k1 for [Cr(bipy)3]2+ was interpreted as being due to the good electron conductivity of the phenanthroline as a ligand in the activated state. The activation parameters were obtained as follows: in the case of [Cr(bipy)3]2+, ΔH\eweq=7.5 kcal/mol and ΔS\eweq=−23 e.u. for the k1 path, and ΔH\eweq=17.2 kcal/mol and ΔS\eweq=−5 e.u. for the k2, path; and in the case of [Cr(phen)3]2+, ΔH\eweq=8.2 kcal/mol and ΔS\eweq=−20 e.u. for the k1 path, and ΔH\eweq=21.2 kcal/mol and ΔS\eweq=+12 e.u. for the k2 path.
Effects of Additives on Solid State Reaction. I. A Kinetic Study of the Effects of Halides of the Formation of MgAl2O4
Authors: Shimada Shiro , Furuichi Ryusaburo , Ishii Tadao
Published: July 2006

The mechanism for the promoting effects of additives on the formation of MgAl2O4 has been systematically discussed from the results of kinetic measurements. A mixture of MgO and α-Al2O3 powder containing 10 mol% additives (LiF, NaF, MgF2, GaF2, BaF2, NaCl or CaCl2) and that without additives were isothermally heated in N2 atmosphere in the temperature ranges 670–1142°C and 1190–1360 °C. The diffusion-controlled Jander’s equation was applied to all kinetic data obtained. In the case of fluoride additives, it has been found that the promoting actions are in the order LiF≥NaF>BaF2>MgF2>CaF2 and that the cations of fluorides play an important role in accelerating diffusion. The same promoting mechanism seems to be applicable in the case of chloride additives.
The Thermal Deaquation-Anation Reactions of Aquopentamminechromium(III) Complexes in the Solid State
Authors: Nagase Kenzo , Yokobayashi Hiroko
Published: July 2006

The thermal deaquation-anation reactions of aquopentamminechromium(III) nitrate, chloride, bromide, and iodide in the solid state were investigated by the techniques of TG, DSC, X-ray powder diffraction analysis, and manometry. The first-order rate constants were obtained by isothermal kinetics. The activation enthalpies calculated from the first-order rate constants increased in the order: the nitrate(24.3)<the chloride(26.4)<the bromide (29.7)<the iodide(30.7 kcal/mol). The enthalpy changes by DSC were 12.3, 6.5, 6.3, and 7.0 kcal/mol for the nitrate, chloride, bromide, and iodide respectively. The slight deviation from the first-order kinetics was observed in cases of the nitrate and the chloride.
Autoxidation of Isobutyraldehyde
Authors: Miyajima Shingo , Inukai Takashi , Harada Hiroshi , Yoshizawa Ryo , Hirai Tadahiro , Matsunaga Kazutoshi , Harada Masato
Published: July 2006

The liquid phase autoxidation of isobutyraldehyde to peroxyisobutyric acid was investigated with ozone as an initiator. The selectivity of the peroxyacid increases with decrease in the amount of aldehyde converted per unit volume of reacting fluid, increase in the ozone feed rate, and decrease in temperature. A few percent of water in solvents increases the selectivity, although too much water brings about a reverse effect. Isopropyl alcohol, acetone, isopropyl formate, propane, propylene, carbon dioxide, and carbon monoxide are observed as by-products besides isobutyric acid. Purified peroxyisobutyric acid (97.2 wt%) was obtained by fractionally distilling the autoxidation product and some of its physical properties were determined. The utility of the peroxyacid as an epoxidizing agent is described.
Application of Chemical Reactions on Thin-layer Chromatoplates. IV. Triterpenes
Authors: Osman A M , Younes M El-Garby , Ata F M
Published: July 2006

Some specific reactions of triterpenoids had been performed on thin-layer chromatoplates. The reactions conducted were: oxidation with oxygen in K-t-butoxide, benzilic acid rearrangement, decarboxylation with lead tetraacetate, Wolff-Kischner reduction, reduction with sodium borohydride, reduction with lithium aluminium hydride, oxidation with chromium trioxide in pyridine and in acetic acid, oxidation with manganese dioxide in chloroform, methylene chloride and isopropyl alcohol, insertion of an oxygen atom in ring A of triterpenoids by the formation of acid anhydride and reduction by a modified Clemmensen method.
The Mass Spectra of Heteroaromatics. II. Mass-spectral Fragmentation of 5-Nitro-2-furohydrazide Imide and Its N2-Acyl Compounds
Authors: Kato Yasuhiko
Published: July 2006

The high-resolution mass spectra of 5-nitro-2-furohydrazide imide and its N2-acetyl, N2-propionyl, and N2-butyryl compounds have been examined. The major fragmentation pathways of the compounds were thus deduced.
Derivatives of Cyclic Bisulfides. III. A New Method of Deoxygenation of Thiolsulfinates and Thiolsulfonates with Inorganic Cyanide
Authors: Tamagaki Seizo , Hirota Hiroo , Oae Shigeru
Published: July 2006

The reaction of rigid cyclic thiolsulfinates and thiolsulfonates such as 1,2-dithiaacenaphthene S-oxide and S,S-dioxide with inorganic cyanide afforded the corresponding reduced 1,2-dithiaacenaphthene, but not the open-chain p-tolyl benzenethiolsulfonate. This was explained by the proximity effect due to the rigidly confined S–S bond at peri-position of the naphthalene ring.
Preparation and Structures of Unsubstituted and Monofluorinated 2H(or 4H)-1,3,4-Benzoxadiazines
Authors: Chow Peng Wai , Ishikawa Nobuo
Published: July 2006

Azo-coupling of diazomethane with benzenediazonium-2-oxide yielded 2H-1,3,4-benzoxadiazine while coupling of the same reagent with the monofluoro-substituted benzenediazonium-2-oxide derivatives gave the corresponding 4H-1,3,4-benzoxadiazines.
The Reductive Amination of d-Camphor with the Methylamine and Carbon-13 NMR of the Reaction Products
Authors: Kiyooka Syun’ichi , Suzuki Kojiro
Published: July 2006

The effects of catalysts (Raney Ni, 5% Pd–C, and PtO2) in the title reactions have been discussed. The PtO2 catalyst is excellent in reductive power and in selectivity. The CMR spectra of the reaction products (I, II, and III) are assigned, and the N-protonation shifts are further measured.
Thermal Decay of the Colored Form in Photochromism of 2-Hydroxy-4-methoxytriphenylmethanol in n-Hexane
Authors: Hamai Sanyo , Kokubun Hiroshi
Published: July 2006

It was found that, like 2-hydroxytriphenylmethanol (HM), 2-hydroxy-4-methoxytriphenylmethanol (HMM) shows photochromism as well as thermochromism. Photo- and thermochromism of HMM occur even in n-hexane, in which a photochemical irreversible reaction occurs for HM. In n-hexane solution of HMM, a three-stage thermal fading pattern was observed at room temperature and at lower temperatures, the pattern becoming a one-stage type at a higher temperature. Mechanical stirring of a sample solution caused a decrease in the concentration of the colored form in n-hexane at room and lower temperatures but not at a higher temperature. These phenomena are caused by the backward reaction on the wall of a sample cell including diffusion as the rate-determining step. In n-hexane–dimethoxyethane (or acetonitrile) mixed solvents, the first-order rate constant becomes smaller with increase in the dimethoxyethane (or acetonitrile) concentration. From a certain concentration, shaking of a cell causes no decrease in the concentration of the colored form.
The Catalytic Activity of AgX-type Zeolite for the Isomerization of 1-Butene
Authors: Sugihara Hiroshi , Chen Ling Yuan , Yasumori Iwao
Published: July 2006

The catalytic activity of X-type zeolite exchanged by Ag+ was studied for the isomerization of 1-butene. The activity gradually increased with the degree of exchange up to ca. 60%, whereafter it rose steeply. A good correlation was found between the activity and the number of acid sites of H0 less than 3.3. Both preferences, that for the formation of cis-2-butene from 1-butene and that for the geometrical isomerization rather than the double bond shift, indicated that the reaction proceeds via a carbonium-ion intermediate formed on an acidic site. In the region of exchange around 40%, however, the cis/trans ratio in the 2-butenes produced was less than unity and a change in the reaction mechanism was suggested. Treatment with H2 enhanced the activity of exchanged zeolite by a factor of 102–103 without any change in the character of the reaction. These results were attributed to the formation of proton-X-zeolite by the replacement of Ag+ with a proton. This conclusion was confirmed by the analysis of deuterium exchange during the isomerization on D2-treated AgX.
Charge-transfer Interaction and Chemical Reaction. V. Reaction of o-Phenylenediamine with Chloranil
Authors: Nogami Takashi , Hishida Tadanori , Shirota Yasuhiko , Mikawa Hiroshi , Nagakura Saburo
Published: July 2006

The reaction of o-phenylenediamine with chloranil in ether was studied by measuring visible and ultraviolet absorption spectra at various temperatures between −78 °C and room temperature. Dehydrogenation of o-phenylenediamine by chloranil occurred, o,o′-diaminoazobenzene, 2,3-diaminophenazine and tetrachlorohydroquinone being produced as main reaction products. It was suggested that the reaction involves o-benzoquinone di-imine as an intermediate. For the sake of confirmation, o-benzoquinone di-imine was prepared by an independent method, and its reaction with o-phenylenediamine was examined. The difference in reactivity of isomeric phenylenediamines toward chloranil is discussed.
Interaction between Electron Donor and Acceptor: MINDO/2 Calculations on the Ammonia–I2, Benzene-I2 and Benzene–TCNE Systems
Authors: Ohta Toshiaki , Fujikawa Takashi , Kuroda Haruo
Published: July 2006

The MINDO/2 method was applied to typical molecular complexes such as ammonia–I2, benzene–I2, and benzene–TCNE, these bimolecular systems being treated as single molecules. The intermolecular interaction energy was calculated as a function of intermolecular distance. Stable complex formation with a reasonable stabilization energy was predicted in the ammonia–I2 system. It was predicted in the benzene–I2 system for the axial model, but not for the resting model. However, the stabilization energy for the former was found to be too large. No stable conformation was found in the case of the benzene–TCNE system.
ESR Study on Fluorescein Semiquinone Radical
Authors: Niizuma Shigeya , Sato Yoshiharu , Konishi Shiro , Kokubun Hiroshi
Published: July 2006

The ESR spectrum of the fluorescein semiquinone radical (dianion form) produced by illumination of an alkaline aqueous solution of uranine and leuco-uranine at pH between 11 and 14 was observed and its hfs constants were determined by comparing the spectrum with those of the mono- and trianion forms of fluorescein semiquinone and those of eosm semiquinone reported by Leaver. Six protons in the xanthene ring were found to be comprised of three pairs of magnetically equivalent protons, which suggests a certain dynamic mechanism to average the coupling constants. From a temperature dependence of the line width, protonation to the –O− group followed by deprotonation from the –OH group was proposed as a plausible mechanism.
The Estimation of Rate Constants in Systems of Linear and Nonlinear Differential Equations Using the Polynomial-approximated Least Squares-error and Iterative Search Technique
Authors: Ohkubo Katsutoshi , Sakamoto Hiroyuki , Tsuchihashi Kohji
Published: July 2006

A new technique is proposed for estimating the rate constants in systems of linear or nonlinear differential equations, using a polynomial approximation of the observed concentrations of species participating in the reaction and an iterative search technique. The method is implemented by minimizing the errors of the concentrations (of species), as computed by the theoretical equations derived from the linear differential equations or by the trapezoidal averaging simulation, relative to those calculated by the polynomial approximation. The present technique requires the concentrations (at the initial reaction stage) of s-2 species (the s species takes part in the reaction). Two kinetic example, A\ightleftarrowsB\ightleftarrowsC and S+E\ightleftarrowsES→P, have been used to illustrate and develop the present technique.
The Protonation of the TCNQ Anion Radical by Hydrogen Chloride
Authors: Yamagishi Akihiko , Sakamoto Masahiro
Published: July 2006

The kinetics of the protonation of sodium salt of 7,7,8,8-tetracyanoquinodimethane (Na+TCNQ\ewdot) by hydrogen chloride in alcohols and acetonitrile was investigated, using a stopped-flow apparatus. In methanol, the protonation rate is first-order in HCl and second-order in Na+TCNQ\ewdot, while in ethanol, the rate is one-half-order in HGl and second-order in Na+TCNQ\ewdot. The protonation rate in acetonitrile is first-order in HCl, but it deviates from second-order in Na+TCNQ\ewdot. These results are interpreted in terms of the rapid formation of a protonated intermediate in the initial stage of the reaction, according to TCNQ\ewdot+H+\ightleftharpoonsHTCNQ\ewdot The reversibility of this reaction is well demonstrated by the second-order dependence of the rate on Na+TCNQ\ewdot. The rate is also compared with the protonation rate of semiquinones, such as sodium salts of p-chloranil and 2,3-dicyano-l,4-benzoquinone, from the view point of the difference in reactivity between carbon and oxygen acids.
Heat Capacity of Nematogenic N-p-Ethoxybenzylidene-p′-butylaniline between 14 and 375 K
Authors: Sorai Michio , Nakamura Teruo , Seki Syûzô
Published: July 2006

The heat capacity of a low-temperature liquid crystal EBBA (N-p-ethoxybenzylidene-p′-butylaniline) of 99.75% (mol) purity was measured in the range 14–375 K with an adiabatic calorimeter. The melting point Tm was 305.62 K, and the enthalpy and entropy of fusion 27.09 kJ mol−1 and 88.71 J K−1 mol−1, respectively. The temperature of mesomorphic transition Tc from nematic to isotropic liquid was 349.08 K, and the enthalpy and the entropy changes due to the mesomorphic transition were 1.553 kJ mol−1 and 4.524 J K−1 mol−1, respectively. Excess heat capacity due to the mesophase transition, C(excess), is represented by C(excess)∼ε−0.7 in the range 10−4<ε<10−1.5, where ε≡|T–Tc|⁄Tc. This implies that the mesomorphic transition of EBBA can be regarded as of critical phenomena, characterized by a second-order rather than a first-order nature.
Studies of Peptide Antibiotics. XXXI. Syntheses of iso-Gramicidin S and iso-[2,2′-Lysine]-Gramicidin S
Authors: Takiguchi Hideo , Izumiya Nobuo
Published: July 2006

Structural isomers of gramicidin S and [2,2′-lysine]-gramicidin S, namely iso-gramicidin S and iso-[2,2′-lysine]-gramicidin S, were prepared to investigate the influence of the ring size for antibacterial activity and conformation of natural gramicidin S. Each isomer involves two peptide bonds between carboxyl group of valine residue and ω-amino group of ornithine or lysine residue. Two isomers showed no antibacterial activity toward several microorganisms. In the experiment of optical rotatory dispersion, two isomers showed similar shaped curves as gramicidin S in a solvent of ethanol. In 6 M urea, the trough of two isomers was moved significantly, whereas that of gramicidin S remained constant.
X-Ray Diffraction Studies of Aqueous Solutions of Cadmium Perchlorate and Sodium Tetraiodocadmate
Authors: Ohtaki Hitoshi , Maeda Masunobu , Ito Satoshi
Published: July 2006

X-Ray diffraction measurements were carried out for aqueous solutions of cadmium perchlorate and sodium tetraiodocadmate. X-Ray scattering data showed that the hydrated Cd2+ ion is coordinated to six water molecules, the distance between Cd2+ and H2O being 2.31±0.02 Å, and that the CdI42− complex has a tetrahedral configuration with a Cd–I distance of 2.79±0.01 Å. The tetrahedral structure of the CdI42− complex was confirmed by Raman spectroscopy.
Polarographic Study of Catalytic Reduction of Tris(2,2′-bipyridine)-copper(II) in the Presence of Nitrite Ion
Authors: Tanaka Kazuyoshi , Nakano Kunio
Published: July 2006

The rigorously derived equation for a catalytic current was applied to the evaluation of the rate constant for the oxidation reaction of bis(2,2′-bipyridine)copper(I) by nitrite ion by use of a computer and subroutine program for the curve-fitting method. This method made it possible to calculate the rate constant from low limiting current in the presence of nitrite ion. The rate in acetate buffer solutions has first-order dependence on each reactant and hydrogen ion, and the apparent rate constant is 1×106 M−2 s−1 at 25 °C.
An X-Ray Investigation of the Structures of the Tetrachloro- and Tetrabromoaurate(III) Ions in Aqueous Solution
Authors: Maeda Masunobu , Ohtaki Hitoshi , Johansson Georg
Published: July 2006

The structures of the AuCl4− and the AuBr4− complexes in aqueous solutions have been determined from X-ray scattering measurements on concentrated solutions of tetrachloroauric and tetrabromoauric acids. Both the tetrachloroaurate(III) and the tetrabromoaurate(III) complexes were found to have a square planar symmetry. The values obtained for the interatomic distances within the complexes are: Au–Cl, 2.291 Å; cis-Cl–Cl, 3.24 Å; trans-Cl–Cl, 4.58 Å; Au–Br, 2.432 Å; cis-Br–Br, 3.44 Å; trans-Br–Br, 4.86 Å.
Atomic Absorption Spectrophotometric Determination of Rare Earths (Y, Eu, Gd, Dy, Ho, and Er) in Single Crystals of Magnetic Garnets and Sulfides
Authors: Ametani Kohei
Published: July 2006

Atomic absorption spectrophotometric studies were carried out on single-crystal rare-earth magnetic garnets, (R1R2)3(Fe,Ga)5O12, where R1 and R2 are Y, Eu, Gd, and Er, and sulfides RCr3S6, where R is Y, Gd, Dy, Ho, and Er. A method using lanthanum chloride to suppress the interference effects of other elements was demonstrated for the atomic-absorption determination of rare earths. Lanthanum chloride is much better than alkaline metal chlorides (NaCl, KCl, and CsCl) and chelating agents (EDTA·2Na and EDTA·2NH4) for removing the interference effects of foreign elements from the yttrium measurement. Similar results with lanthanum chloride are observed with other rare earths. Experimental results for various samples are also presented. The present method has been utilized for several years in our laboratories to analyse rare earths in newly prepared materials.
Photochemical Reactions of Some 1-Aryl-1,2-propanediones
Authors: Ogata Yoshiro , Takagi Katsuhiko
Published: July 2006

Irradiation of four 1-aryl-1,2-propanediones (Ia–Id) with over 300 nm light in 2-propanol gives reduction products identified to be the corresponding pinacols or hydrols formed by the reduction at the aroyl (but not acetyl) oxygen. The products from 1-(o-tolyl)-1,2-propanedione (Id) can also be accounted for by the initial hydrogen abstraction from ortho methyl by the aroyl carbonyl oxygen. Their photoreactivities are discussed as regards their electronic emission spectra and triplet configuration.
Sulfur-containing Polymers. XIII. The Synthesis and Properties of Soluble Polydithiocarbamates
Authors: Kobayashi Norio , Osawa Akiko , Fujisawa Tamotsu
Published: July 2006

Polydithiocarbamates have been synthesized by the polycondensation of di-K or di-Na bisdithiocarbamates based on secondary diamines with bischloromethylated aromatics in N,N-dimethylformamide. The polymers obtained in good yields had inherent viscosities up to 0.66. The polymers derived from 1,3-di-4-piperidylpropane were soluble in organic solvents, such as dichloromethane and chloroform, and gave transparent, tough films from the solution. These polymers decomposed upon UV irradiation, with the liberation of carbon disulfide. The photopolymerization of methyl methacrylate in the presence of the polymer has also been studied.
Nucleosides. XXI. Preparative Routes to Nucleosides Derived from 4-Amino-4-deoxy-β-d-glucopyranose
Authors: Lichtenthaler Frieder W , Voss Peter , Bambach Gerd
Published: July 2006

Four-step syntheses for the 4′-arnino-4′-deoxy-β-d-glucopyranosyl nucleosides of adenine (7), uracil (12) and cytosine (16) from a readily accessible galactose derivative (2) are described, in overall yields of 41–47%. The reaction sequence, used, involved (i) stannic chloride catalyzed nucleosidations of 2 with the bis-trimethylsilyl derivatives of N6-benzoyladenine, uracil and N4-acetylcytosine, (ii) displacement of the 4′-sulfonyloxy groups in 3, 10, and 15 by azide, (iii) de-O-benzoylation and (iv) hydrogenation. An alternate route to 12 and 16, comprising nucleosidation of tetraacetyl-4-acetamido-4-deoxy-d-glucopyranose (20) via the classical Hilbert-Johnson approach proved feasable, yet inferior with respect to yields and accessibility of educts. The structures and configurations assigned followed from the synthetic route as well as from spectroscopic data, particularly from the acetyl resonances of the peracetylated nucleosides 9, 14, and 18, which are in excellent agreement with those of the respective glucosyl- and 3-acetamido-3-deoxy-glucosyl analogs (Table).
Nucleosides. XXII. Pyrimidine Nucleosides of 4-Amino-4-deoxy-β-d-galactopyranose
Authors: Lichtenthaler Frieder W , Ueno Tamio , Voss Peter
Published: July 2006

In a four step sequence from 1-O-acetyl-2,3,6-tri-O-benzoyl-4-O-mesyl-α-d-glucose (4), 4′-amino-4′-deoxy-β-d-galactosyl-cytosine (1) was synthesized, involving stannic chloride catalyzed nucleosidation with bis(trimethylsilyl)-N4-acetyl-cytosine, azidolysis of the 4′-sulfonyloxy group, deblocking and reduction (overall yield: 48%). An alternate, though preparatively less satisfactory approach was used for the preparation of the uracil analogue 2, which started from β-d-glucosyl-cytosine or uracil (9 or 15) and proceeded via standard blocking and deblocking reactions to the 4′-O-mesylglucosyl-uracil (20) and was concluded by azidolysis (20, 21), removal of protecting groups and reduction. Structural and configurational assignments evolved from the mode of preparation as well as from spectroscopic data, most conveniently from the acetyl resonances of the peracetylated nucleosides 8 and 24, which are in accord with those of their galactosyl and 3-acetamido-3-deoxy-galactosyl counterparts (Table).
Reaction of Methylcyclopentane and n-Hexane over Evaporated Platinum Film Catalysts
Authors: Anderson J R , Shimomura Kin’ya
Published: July 2006

In the reaction of n-hexane and methylcyclopentane over polycrystalline platinum films evaporated in a ultrahigh vacuum condition, the initial distribution of reaction products varied with the reaction temperature and the hydrogen/hydrocarbon ratio. The effect of the reaction conditions was interpreted as depending on the possible reaction mechanisms cited.
Adsorption of Aniline Derivatives on Platinum Electrode in Aqueous Alkaline Solution
Authors: Matsuda Yoshiharu , Ishikawa Yukio , Tamura Hideo
Published: July 2006

In the adsorption of aniline derivatives on Pt electrode, a linear relation was observed between the chemical shift of the m- and p-amino protons and the inhibiting effect on the anodic oxidation of methanol. However, o-alkylanilines and chloroanilines showed deviations due to steric hindrance and strong interactions, respectively.