bluuebunny/crossref_metadata_2025 huggingface dataset:
Luminescence in DNA-Acridine Dye Complexes. II. Sensitized Delayed Fluorescence in the Complexes
Authors: Kubota Yukio
Published: July 2006

When frozen aqueous solutions of DNA-acridine dye complexes or nucleotide-dye mixtures were excited by ultraviolet light, a sensitized delayed fluorescence of the dye was observed. This delayed fluorescence was interpreted by means of a mechanism in which the excitation energy is transferred from the triplet state of the nucleotides to the first excited singlet state of the dye. The efficiency and decays of the sensitized delayed fluorescence revealed that the energy transfer depends greatly on the separation between the energy donor and acceptor and that donor-acceptor pairs spaced very closely are important in the energy transfer. In DNA-acridine dye complexes, the thymine triplet seems to play the most important role as an energy donor. The decrease in the delayed fluorescence on the denaturation of DNA indicates that the energy transfer is sensitive to the conformation of the macromolecule.
An ESR Study of Monomeric Cobalt Oxygen Complexes in Solutions
Authors: Koda Seiichiro , Misono Akira , Uchida Yasuzo
Published: July 2006

Several mononuclear cobalt oxygen complexes in solutions have been investigated by means of ESR measurements. When a pyridine (and also substituted pyridines, N,N-dimethylformamide, dimethyl sulfoxide, and hexamethylphosphoramide) solution of a bis-salicylaldehyde-imine cobalt-(II) complex (N,N′-ethylene-bis(salicylideneiminato)cobalt(II), and N,N′-ethylene-bis(3-methoxysalicylideneiminato)cobalt(II)) was exposed to oxygen, there appeared a reversible ESR signal, in which a hf structure of eight lines caused by a mononuclear cobalt was observed. This spectrum could be analysed by considering the species to be essentially a superoxide cobalt(III). We tried to explain the deviations in the ACo and the g values of the species from solvent to solvent by considering that the solvent coodinates to the cobalt complex in the trans position against the coodinated oxygen. As a comparative study, the mononuclear oxygen adduct of di(salicylal)-3,3′-diimino-di-n-propylamine-cobalt(II) was also studied in the above solvents.
The Photometric Determination of Micro Amounts of Bromine in Silicate Rocks by Means of Its Catalytic Effect
Authors: Takahashi Kazuyoshi , Yoshida Minoru , Ozawa Takejiro , Iwasaki Iwaji
Published: July 2006

The catalytic action of bromide on the oxidation of to iodine iodate by potassium permanganate in sulfuric acid solution has been utilized for the microdetermination of bromine in silicate rocks. The method described consists of decomposing the silicate-rock sample by fusion with potassium hydroxide, leaching the melt with water, oxidizing bromide to bromine with potassium permanganate, extracting by benzene, and finally determining the bromine by the catalytic method. By this method, the bromine in samples with more than 0.04 ppm can be determined rapidly and accurately, using only 0.25–0.5 g of samples.
A Spectrophotometric Study of Indoferron as a Color Reagent for Zirconium(IV) and Iron(III)
Authors: Sakai Takayoshi
Published: July 2006

Indoferron is shown to be a useful spectrophotometric reagent for the determination of zirconium(IV) and iron(III). An excess reagent reacts with zirconium(IV) and iron(III) to form blue complexes, which have absorption maxima at 605 and 590 mμ respectively against the reagent blank. The maximum absorbances of the solutions containing the complexes are obtained in the pH range from 3.6 to 3.7 for zirconium(IV), and in that from 3.9 to 4.1 for iron(III). The former complex is stable for 1 hr, and the latter, for 4 hrs. The color systems obey Beer’s law in 25 ml over the ranges up to 40 μg Zr and up to 50 μg Fe respectively. The molar absorptivities of the complexes are calculated to be 3.18 ×104 for zirconium(IV) and 1.81 ×104 for iron(III). The sensitivities of the reactions are 0.0038 μg Zr/cm2 and 0.0039 μg Fe/cm2 for an absorbance of 0.001. As for composition, the complexes used have a metal-to-ligand ratio of 1:3 for zirconium-(IV) and 1:2 for iron(III). The apparent formation constant of the complex for iron(III) is calculated to be 7.81 ×1010.
Tri(hetero)substituted Carbonium Ions. III. Ring-size Effects on the Dual Reactivities of 2-Dimethylamino-1,3-dithiolanylium Ion and Its Ring Analogs as Ambident Electrophiles
Authors: Nakai Takeshi , Ueno Yoshio , Okawara Makoto
Published: July 2006

The following ring analogs of 2-dimethylamino-1,3-dithiolanylium perchlorate (Ia) were prepared: 2-dimethylamino-1,3-dithianylium perchlorate (IV), 2-dimethylamino-1,3-dithiepanylium perchlorate (V) and an open-chain analog, bis(methylthio)dimethylaminocarbonium perchlorate (VI). In order to investigate the structural effect on the reactivities of the tri(hetero)carbonium ions at two reactive sites, i. e., the centered carbon (sp2) (a) and the S-methylene carbon (sp3) atoms (b), the reactions of these carbonium ions with hydroxide ion (mode A) and with N,N-dimethyldithiocarbamate ion (mode B), respectively, were studied at 30°C. The rates of mode A of these carbonium ions, relative to that of Ia, are 1 : 15.0 (IV) : 32.5 (V) : 1.06×104 (VI), and of mode B are 1 : 6.5 : 23.5 : ≈2.0×104. In their electronic spectra a definite trend that as the ring-size increases there is a strong shift of absorption maxima toward the lower energies was observed. The fact suggests that the stability of the carbonium ion decreases with an increase in ring-size. On the basis of the schematic energy profiles for the two modes as well as the structural and kinetical aspects, it has been assumed that one of common factors contributing to the ringsize effect on both reactivities would be the stability of the carbonium ion.
The Carbon-13 NMR Spectra of Alkyl Vinyl Ethers, and Their Structures and Reactivities
Authors: Hatada Koichi , Nagata Kazuhiko , Yuki Heimei
Published: July 2006

The 13C NMR spectra of alkyl vinyl ethers were investigated at 22.5°C with neat liquid at 15.09 MHz. When the alkyl group of the ether becomes more electron-donating, the chemical shift of the α-carbon of the vinyl group shifts to a higher field, and that of the β-carbon, to a lower field. From these results, it was concluded that the contribution of the resonance form, \barCH2–CH=\overset+O–R, in the ether decreases in the order of the increasing electron-repelling power of the alkyl group. Good correlations were obtained between the chemical shifts of the vinyl group and the reactivity of vinyl ether in the cationic reaction. When the ether becomes more reactive, the chemical shift of the α-carbon shifts to a higher field, and that of the β-carbon to a lower field. This fact clearly shows that the attack of the proton on the β-carbon is not the rate determining step in the cationic reaction of the vinyl group. Linear relations were obtained between the chemical shifts of β-methylene protons and of β-carbon, but no correlation was obtained between the chemical shifts of the α-methine proton and of the α-carbon.
Reactions between β-Propiolactone and Dialkyl Dimethylphosphoramidite-Ambident Character of β-Propiolactone and of Dialkyl Dimethylphosphoramidite
Authors: Koketsu Jugo , Kojima Seiji , Ishii Yoshio
Published: July 2006

The reactions between dialkyl dimethylphosphoramidite, Me2NP(OR)2, and β-propiolactone were carried out in various solvents at 80°C. Two kinds of reaction products were separated on a silica gel by elution with benzene-ethanol (4:1 v/v). The first species eluted was N,N-dimethyl-O-alkyl 2-alkoxycarbonylethylphosphoramidate, (RO)P(O)(NMe2)CH2CH2CO2R. The fraction having lower Rf value contained dialkyl 2-N,N-dimethylcarbamoylethylphosphonate, (RO)2P(O)CH2CH2CONMe2. The reaction mechanism is discussed from kinetic study.
Syntheses of Some Derivatives of d-Glucuronic Acid
Authors: Irimajiri Takeshi , Yoshida Hiroshi , Ogata Tsuyoshi , Inokawa Saburo
Published: July 2006

The syntheses of some derivatives of d-glucuronic acid from d-glucofuranurono-6→3-lactone have been investigated. That is, 5-bromo-5-deoxy-1,2-O-isopropylidene-β-l-idofuranurono-6→3-lactone (2) and 5-bromo-5-deoxy-1,2-O-isopropylidene-α-d-glucofuranurono-6→3-lactone (3) were prepared by heating 1,2-O-isopropylidene-5-O-(p-toluenesulfonyl)-α-d-glucofuranurono-6→3-lactone (1) with lithium bromide in dimethylformamide (DMF); methyl 5-O-(p-toluenesulfonyl)-β-d-glucofuranurono-6→3-lactone, 5-bromo-5-deoxy-α-l-idofuranurono-6→3-lactone, and 5-bromo-5-deoxy-β-d-glucofuranurono-6→3-lactone were prepared by heating 1, 2, and 3 respectively in methanol in the presence of strong acidic ion-exchange resins; 5-deoxy-1,2-O-isopropylidene-α-d-glucofuranurono-6→3-lactone (7) was prepared by the reaction of 2 with thiolacetic acid of benzylmercaptan in pyridine or by the reaction of 2 with triethyl phosphite; 5-bromo-5-deoxy-1,2-O-isopropylidene-β-l-ido-hexodialdo-3,6-furanoid(6S)-1,4-furanose (8) was prepared by the reduction of 2 with lithium aluminum hydride; 1,2-O-isopropylidene-5-O-(p-toluenesulfonyl)-α-d-gluco-hexodialdo-3,6-furanoid-1,4-furanose and 1,2-O-isopropylidene-5-O-(p-toluenesulfonyl)-α-d-glucofuranose (10) were prepared by the reduction of 1 with lithium aluminum hydride, and 1,2;3,6-di-O-isopropylidene-5-O-(p-toluenesulfonyl)-α-d-glucofuranose and 3,6-di-O-acetyl-1,2-O-isopropylidene-5-O-(p-toluenesulfonyl)-α-d-glucofuranose were prepared by the acetonation and the acetylation of 10 respectively.
The Crystal and Molecular Structure of Tetrodotoxin Hydrobromide
Authors: Furusaki Akio , Tomiie Yujiro , Nitta Isamu
Published: July 2006

The crystal and molecular structure of the hydrobromide of tetrodotoxin itself, C11H17O8N3·HBr, have been studied by means of three-dimensional X-ray analysis. The crystals are tri-clinic, with two formula units in a unit cell of the dimensions; a=8.79, b=9.02, c=9.51 A, α=106°51′, β=88°1′, and γ=96°23′; the space group is pl. The intensities of reflections were recorded on equi-inclination Weissenberg photographs taken with CuKα radiation around the b and c axes, and were measured visually with a calibrated intensity scale. The structure was elucidated by means of the Fourier and least-squares methods, and was refined by the block-diagonalmatrix least-squares method, the anisotropic thermal motion being assumed only for bromine atoms. The stereostructures of the two crystallographically-independent molecules of tetrodotoxin thus obtained are almost identical and correspond to that deduced by Tsuda et al., by Hirata et al., and by Woodward et al., all in 1964. It is noteworthy that, in both of the two molecules, the C–O distance for the free hydroxyl group in the ortho-ester part (1.36 and 1.39 Å) is somewhat smaller than the ordinary aliphatic C–O distance, 1.43±0.01 Å, and that it is rather closer to the phenolic C–O distance, 1.36±0.01 Å.
Structure of Polynucleotide Complex with Non-Complementary Nucleosides. I. Poly A,G+Poly U
Authors: Akutsu Hideo , Tsuboi Masamichi
Published: July 2006

Copolymers of riboadenylic and riboguanylic acids (poly A,G) with guanylic acid contents of 8.5–29.6% were prepared. The ultraviolet and infrared absorptions were examined of aqueous solutions of mixtures of poly A,G and polyribouridylic acid (poly U) of various mole ratios. It has been shown that in a solvent with 0.1 m Na+ a triple-helical structure is formed with a (Remark: Graphics omitted.) type inter-base binding as well as a double-helical structure with a A···U type binding, while in a solvent with 0.01 M Na+ only double-helical structure is formed. A guanine residue in the copolymer remains within the helix structure when its neighbors are mostly adenine residues, whereas it rotates out when there are many guanine residues in its vicity. On heating the solution, the structures just mentioned were found to be broken. The process of such a breaking down was followed also by means of the ultraviolet and infrared absorption measurements.
Quantum Yield of Photo-rearrangement of Nitrones
Authors: Koyano Kinko , Suzuki Hiroshi , Mori Yuji , Tanaka Ikuzo
Published: July 2006

Fifteen nitrones, N-butylidenecyclohexylamine N-oxide, N-benzylidenemethylamine N-oxide, N-diphenylmethylenemethylamine N-oxide, N-benzylidenaniline N-oxide, and its derivatives, were irradiated with light in solution, each at its longest-wavelength absorption band. Each nitrone isomerized to the corresponding oxazirane. The quantum yield of this photo-rearrangement, Φ, was measured. For each nitrone, the value of Φ is larger in cyclohexane solution than in ethanol solution. In the series of N-benzylidenaniline N-oxide and its para-substituted derivatives, the substituent lowers Φ, and the more electron-donating or the more electron-withdrawing the substituent is, the smaller is Φ. These facts are explained on the basis of a hypothesis that π should increase with the change in the π-bond order between the carbon and oxygen atoms of the nitrone group upon the lowest-energy electron excitation, ΔPC,O, calculated by the simple MO method.
The Polymerization of Vinyl Monomers in the Presence of Surface Active Agents. I. The Polymerization of Methyl Methacrylate
Authors: Asahara Teruzo , Sen\={o} Manabu , Shiraishi Shinsaku , Arita Yoshikazu
Published: July 2006

Methyl methacrylate polymerized in the presence of a surface active agent in an aqueous system without any ordinary initiators. Anionic surface active agents, such as sodium tetrapropylenebenzenesulfonate and sodium 2-dodecylbenzenesulfonate, markedly effected the polymerization of methyl methacrylate in the presence of water. The polymerization was inhibited by adding hydroquinone to the reaction system and was also affected adversely by oxygen. Water as a reaction medium was found to be indispensable. The polymerization in organic solvents afforded hardly any polymeric products.
Studies of Phosphorylation. IV. The Phosphorylation of Nucleosides with Phosphorus Trihalide
Authors: Yoshikawa Masaharu , Sakuraba Mitsuru , Kusashio Koji
Published: July 2006

The treatment of a 2′,3′-O-isopropylidene nucleoside with phosphorus trichloride in the presence of trimethyl phosphate and subsequent hydrolysis gave a nucleoside 5′-phosphite in an excellent yield. Triaryl phosphates, trialkylphosphine oxides, and trialkyl phosphites were also found to be potential accelerators of the reaction. Their effects were comparable to that of trimethyl phosphate. The similar treatment of a 5′-O-acetyl nucleoside gave mixed nucleoside 2′- and 3′-phosphites in an approximate mole ratio of 4 : 6. The reaction intermediate, nucleoside phosphorodichloridite, was subjected to partial hydrolysis, giving the corresponding monochloridite. The product was readily oxidized to give the 5′-nucleotide. Chlorine was generally suitable as an oxidizing agent, but iodine gave better results for guanosine derivatives than did chlorine or bromine. The treatment of an unprotected nucleoside with phosphorus oxychloride in a trialkyl phosphate, prior to the reaction with phosphorus trichloride, could be used for the synthesis of a nucleoside 2′(or 3′),5′-diphosphate in a good yield.
A-Substituted 5β-Steroids. III. Synthesis of 2-Oxo- 5β-steroids and Their Derivatives
Authors: Satoh Yasuo , Horiuchi Akira , Hagitani Akira
Published: July 2006

The synthesis of 2-oxo- 5β-steroids (5β-cholestan-2-one and methyl 2-oxocholanate) and their derivatives have been described. Both oxo-steroids were prepared from 2β-acetoxy-3-oxo- 5β-ste-roids according to the following synthetic pathways: (a) condensation with ethylmercaptan to diethylmercaptol, desulfurization, hydrolysis and oxidation, (b) condensation with ethylmercaptan to diethylmercaptol, hydrolysis to hydroxy-ethylmercaptol, desulfurization and oxidation, and (c) isomerisation to 3α-acetoxy-2-oxo derivative and deacetylation with zinc powder to 2-oxo derivative. In these pathways, it was found that method (b) gave the best yield. On the other hand, desulfurization of the hydroxy-mercaptols with one-half the weight of Raney nickel used for that of method (b) gave 2β-hydroxy- 3β-ethylthio derivatives as intermediates. Reductive cleavage of these hydroxy-ethylthio derivatives with Raney nickel produced 2β-hydroxy- 5β-steroids in good yields. In the halogenation of these 2-oxo derivatives, the products were 1β-halo-2-oxo- 5β-sterodis, not 1α- or 3-halo isomers.
The Kinetics of the Chromic Acid Oxidation of Phenylphosphonous Acid
Authors: Sen Gupta Kalyan K
Published: July 2006

The kinetics of the oxidation of phenylphosphonous acid by chromic acid has been investigated. The rate at which gross concentration of chromium (VI) disappears follows a first order law. The rate increased with the increase of hydrogen ion concentration. The activation energy of the reaction was found to be 7.4 kcal. The effect of pyridine on the reaction rate confirmed the findings of Westheimer who showed that pyridine catalyzes the oxidation of isopropyl alcohol. It is suggested that the oxidation appears to proceed through the initial formation of an intermediate compound between the active form of phenylphosphonous acid with chromic acid which finally decomposes slowly by the rate determining step. The inactive form is finally oxidized by chromium(V) by very fast step.
Kinetic Investigations of the Reaction of Brilliant Green with Alkalies. Influence of Ionic Strength
Authors: Katiyar Sarvagya S
Published: July 2006

Kinetic studies of the reaction of brilliant green with alkalies have been made by following the reaction spectrophotometrically at 625 mμ. The reaction has been found to be bimolecular but under experimental condition of excess alkali, it obeyed a first order law. The rate constants was independent of the concentration of brilliant green but it varied linearly with the hydroxyl ion concentration. Effect of neutral salt on the rate of reaction was investigated in aqueous and in 40% acetone-water media. The rate was found to decrease progressively with increasing ionic strength in both media. Analysis of the data by Brφnsted-Christiansen-Scatchard equation yielded a value of −1 for ZaZb indicating thereby that the rate-determining step involves oppositely charged species possessing unit charge. The value of inoic interaction parameter, ai corresponded to 1.5 and 4.75 Å in aqueous and 40% acetone-water medium respectively. Without attaching too precise a meaning to ai it is suggested that B.G. ion is presumably solvated to a greater extent in 40% acetone-water than pure water.
Ultrasonic Study of Dilute Aqueous Solutions of Urea, Guanidine Hydrochloride and Dioxane
Authors: Arakawa Kiyoshi , Takenaka Nobuo , Sasaki Katsutaka
Published: July 2006

An ultrasonic study on dilute aqueous solutions of urea, guanidine hydrochloride and dioxane was made by means of a pulse method, with the intention of investigating the influence of these solutes upon the structure of water. Ultrasonic absorption coefficient was measured in the range of frequency from 15 to 45 Mc/sec, and ultrasonic velocity was measured at 5 Mc/sec. Temperature was varied from 10 to 40°C. In urea solutions, the magnitude of α⁄f2 (α=absorption coefficient, f= frequency) decreases first very slowly with concentration, then rapidly in the range from about 0.5 to 3m and at about 4–6m reaches a nearly constant value. In guanidine hydrochloride solutions a similar change in the relation α⁄f2  vs. concentration takes place with a smaller amount than in urea solution. This shows that guanidine hydrochloride has greater ability as a structure breaker in liquid water than urea. In the dioxane-water system, absorption increases with the concentration of dioxane. A nearly flat region in the absorption vs. concentration curve is found for a small concentration of dioxane.

This feature in the α⁄f2vs. concentration curve, which is found in the small concentration region, is ascribed to the “cooperative breaking effect” upon the “open-packed structure” in water.
The Reactivity of the Electron Donor-Accepter Complex—Catalysis by 1,3-Dimethylalloxazine in an Enzymatic Model Reaction
Authors: Iwasawa Yasuhiro , Soma Mitsuyuki , Onishi Takaharu , Tamaru Kenzi
Published: July 2006

The effect of electron donor-accepter(EDA)-complex formation upon the reactivity (or catalytic activity) of 1,3-dimethylalloxazine, a model compound of co-enzyme, FMN, was examined in the redox reaction between methylene blue and ascorbic acid. The 1,3-dimethylalloxazine exhibited a behavior similar to the enzyme, having an optimal pH for the redox reaction. The characteristic behavior of 1,3-dimethylalloxazine was demonstrated in the presence of both 1,3-dimethylalloxazine and pyrene; such behavior was not to be observed upon the addition of either of them. It was accordingly suggested that the EDA complex formation would play an important role in the enzymatic reactions in vivo. The influence of various aromatic hydrocarbons upon the enzyme-like catalysis was examined.
Formation Constants of Chromium(II) Complexes with (O,O)-, (O,N)- and (N,N)-Type Ligands and Comparison with Those of the Other First Transition Metal Complexes
Authors: Fukuda Yutaka , Kyuno Eishin , Tsuchiya Ryokichi
Published: July 2006

The formation constants of the bivalent chromium complexes with various chelating ligands were determined by the pH titration method at the ionic strength μ=0.1 and at 25°C. The values of the formation constants for (O,O)-type complexes were logk1=3.85±0.05 and logk2=2.96±0.05 for oxalate ion, logk1=3.92±0.05 and logk2=3.21±0.05 for malonate ion, and logk1=9.89±0.05 for sulfosalicylate ion: for (O,N)-type complexes we obtained logk1=7.72±0.05 and logk2=7.54±0.05 for glycine, logk1=9.05±0.05 for 8-hydroxyquinoline, and logk1=7.53±0.05 for β-alanine. Based on these values together with the corresponding values of the (N,N)-type complexes, the effect of the coordinating atoms and of the number of members in a chelate ring upon the stabilities was discussed. These values were compared with those for the other transition metal complexes.
Polarography of Iron(III)- and Europium(III)-Acetylacetonate Complexes in N,N-Dimethylformamide
Authors: Misumi Seizo , Aihara Makoto , Nonaka Yasuomi
Published: July 2006

The reduction potentials of Fe(acac)3 and Eu(acac)3 in DMF are shifted to more positive potentials by the addition of cations (Li+ and Mg2+) to the supporting electrolyte of tetraethylammonium perchlorate. Studies of the complexes show that the effect is caused by coordinative relaxation reaction of the Fe(acac)3− reduction product in which acetylacetonate ligand becomes transferred to the cation. However, in the case of Eu(acac)3−, acetylacetonate ligands seemed to be completely stripped off. Cyclic voltammetric data indicate reduction and reoxidation processes of the complexes.
Benzyl Bromide-Amine Reaction in Nitrobenzene-Ethanol Mixtures
Authors: Radhakrishnamurti P S , Panigrahi G P
Published: July 2006

The reactions between benzyl bromide and various bases as well as p-nitrobenzyl bromide and various bases have been studied in nitrobenzene-ethanol mixtures (80:20 v/v). The reaction is total second order as stated earlier. Comparison is made with the previous work on the same reaction with benzyl chloride and p-nitrobenzyl chloride.
Synthesis of Furonaphthoquinones
Authors: Kakisawa Hiroshi , Tateishi Mitsuru
Published: July 2006

The reaction of 2-acetoxy-1,4-naphthoquinone with N-(1-propenyl)morpholine in an ordinary atomsphere afforded 3-methylnaphtho[2,3-b]furan-4,9-quinone in a modest yield. When this reaction was carried out in an atmosphere of nitrogen, the reaction product was an aminodihydronaphthofuran XII, which was then converted into 3-methylnaphtho[1,2-b]-2,3-dihydrofuran-4,5-quinone by succesive treatments with ferric chloride, sodium borohydride, and sufuric acid.
The Reductive Coupling Reactions of Some Chloromethylbenzene Derivatives with Iron(II) and Copper(I) Complexes
Authors: Onuma Kazuhiko , Yamashita Junzo , Hashimoto Harukichi
Published: July 2006

The reductive coupling reactions of some chloromethylbenzene derivatives with ferrous and cuprous chloride in ethanol or in acetonitrile and the effect of some additives on this reaction have been investigated. Benzotrichloride has been reduced selectively to tolan tetrachloride with ferrous chloride, while with cuprous chloride-ethylenediamine (a stronger reductant than ferrous chloride) mixtures of tolan and tolan dichloride or tolan tetrachloride are obtained depending on the condition. Similarly benzal chloride, diphenylmethyl chloride and diphenyldichloromethane are also reduced to give coupling products. In case of ferrous chloride the addition of ethylenediamine or pyrophosphoric acid raises the yield considerably and in case of cuprous chloride selection of the ratio, organic halide: copper (I): ethylenediamine, makes it possible to control the product distribution. The reaction mechanism and the effect of the additives are discussed.
Intermediate Stages of the Nitration of Hexamethylbenzene to Dinitroprehnitene
Authors: Suzuki Hitomi
Published: July 2006

A syrupy substance formed in quantity during the nitration of hexamethylbenzene to dinitroprehnitene has been found to be a complex mixture of varying amounts, depending markedly on the conditions, of 2,3,4,5,6-pentamethylbenzyl nitrate, 5,6-bis(nitrooxymethyl)-1,2,3,4-tetramethylbenzene, nitropentamethylbenzene, 6-nitro-2,3,4,5-tetramethylbenzyl nitrate, 2,3,4,5,6-pentamethylphenylnitromethane, bis (2,3,4,5,6-pentamethylbenzyl) ether, pentamethylbenzaldehyde, and several other unidentified carbonyl compounds, nitrite esters, and aliphatic nitro compounds. On the basis of the products isolated, a possible path by which hexamethylbenzene can be converted into dinitroprehnitene has been suggested.
The Total Synthesis of Dehexyl-deisovaleryloxy-antimycin A1
Authors: Kinoshita Mitsuhiro , Umezawa Sumio
Published: July 2006

A biologically active prototype of antimycin A series has been synthesized. The dilactone moiety was synthesized from a masked l-threonine and γ-hydroxyvalerate and condensed with an O-masked derivative of 3-nitrosalicylic acid N-hydroxysuccinimide ester. Hydrogenation followed by formylation afforded the anti-fungal substance. This synthesis established a possible general synthetic pathway to the members of antimycin A.
The Catalytic Oxidation of Carbon Monoxide on Titanium Dioxide; Anatase and Rutile
Authors: Onishi Yoshito , Hamamura Takuya
Published: July 2006

For the purpose of investigating the correlation between the crystal structure of titanium dioxide and its catalytic activity, the catalytic oxidation rate of carbon monoxide and the desorption rate of oxygen from the sample surface have been measured on anatase, rutile, and an anatase-rutile mixture. The oxidation of carbon monoxide was investigated by a static method at temperatures of 250–550°C and under gas pressures of 10−2–150 mmHg. The desorption of oxygen was carried out at 600–750°C. The reaction rate was proportional to PCO and did not depend on either PCO2 or PCO2 The activation energy was 16.0 kcal/mol for anatase and 6.7 kcal/mol for rutile. The catalytic activity per unit of the surface area of rutile was 3—6 times as much as that of anatase. The reaction rate almost coincided with the rate of the reduction of titanium dioxide by carbon monoxide. The electric resistance of the sample was little affected by the PO2. The following reaction mechanism is proposed to explain the results. The rate-determining step is the reaction between the surface oxygen of the sample and the carbon monoxide physisorbed or that which has just collided with the surface coming from the gas phase; the oxygen vacancy thus formed on the surface is quickly filled with oxygen of the gas phase. The difference in the activation energy of the catalytic action between the two structures is based upon the difference in the activation energy of the oxygen desorption from the surface structure; the activation energies are 57.8 kcal/mol for anatase and 38.4 kcal/mol for rutile.
Formation of Hypophosphate in the Radiolysis of Phosphite Solution
Authors: Matsuura Niro , Yoshimura Masahito , Takizawa Masao , Sakaki Yukio
Published: July 2006

The formation of hypophosphate and phosphate in the radiolysis of a phosphite solution was established by the anion-exchange chromatographic technique. The quantitative determination of their yields was made by colorimetry of the phosphate and hypophosphate with the Mo(V)+Mo(VI) reagent, which develops molybdenum-blue colors in two steps at different temperatures. The G values in an aerated condition are 0.01 molecules/100 eV in acid and 0.1 molecule/100 eV in neutral pH with respect to the hypophosphate formation, independent of the phosphite concentration. In a deaerated system much higher values are obtained, amounting to around 0.5 molecules/100 eV at a phosphite concentration of 10−3  m. The G values of hypophosphate plus phosphate are around 3.0; this is in agreement with the half-value of the primary radical yields, 1/2·(gred+gOH), reported in the data derived from the radiation-chemical studies in the aqueous system. The hypothesis that the hypophosphate (IV) ion radical is a transient species in the oxidation of phosphite to phosphate is supported by the results obtained in this work.
The Solvent Effect on the Reaction of 1,1,4,4-Tetraphenyl-2-halobuta-2,3-dien-1-ol with Mercuric Halide
Authors: Toda Fumio , Ooi Nobuhiro , Akagi Katsuhiko
Published: July 2006

The reaction of the title compound (I) with mercuric halide in an aprotic and in a protic solvent afforded the fulvene derivative (VII) and the dihydrofuran derivative (VIII or IX) respectively. Both the cross-reactions (bromo-analog of I (Ia)+HgCl2, chloro-analog of I (Ib)+HgBr2) in an aprotic solvent afforded the chloro-fulvene derivative (VIIb). However, when the above reactions were carried out in a protic solvent, the product was the dihydrofuran derivative (IX), in which the halogen combining with carbon is chlorine and that combining with mercury is bromine. On the basis of the results of those cross-reactions, the reaction mechanism will be discussed. Acetonitrile showed distinctive behavior. In acetonitrile, the bromine of Ia was easily exchanged with the chlorine of sodium chloride at room temperature, and Ib was obtained quantitatively.
Sterically Controlled Syntheses of Optically Active Organic Compounds. XIII. Catalytic Hydrogenation of Symmetric Substrates in the Presence of Asymmetric Molecules
Authors: Yoshida Takao , Harada Kaoru
Published: July 2006

Several organic acids which contain C=O, C=N, and C=C double bonds are catalytically hydrogenated in the presence of various optically active organic bases by the use of several solvent systems. Effects of bases and solvents on the optical activities of the products are examined.
Syntheses and Reactions of Functional Polymers. LIV. Syntheses and Polymerizations of O-Substituted-N-hydroxymaleimides
Authors: Narita Mitsuaki , Teramoto Takero , Okawara Makoto
Published: July 2006

The reverse Diels-Alder reaction of N-substituted maleimide adducts of furan is a useful method for the preparation of N-substituted maleimides which can not be obtained by the direct dehydration of maleamic acids owing to the formation of the corresponding isomaleimides. O-Benzyl, O-acetyl, O-benzoyl, O-benzenesulfonyl, and O-methyl-N-hydroxymaleimide adducts of furan decompose at 140–190°C to produce the corresponding maleimides. The homo- and co-polymerization with styrene of these maleimides were carried out and monomer reactivity ratios and Q-e values for these maleimides were determined. The copolymer obtained were converted to the copolymer of N-hydroxymaleimide and styrene.
The Stereochemistry of Nucleophilic Addition. I. The Reformatsky Reaction of 2-Methyl- and 2-Ethylcyclohexanones
Authors: Matsumoto Takashi , Fukui Kenji
Published: July 2006

The Reformatsky reaction of 2-methyl- or 2-ethylcyclohexanone with ethyl bromoacetate gave a mixture of epimeric alcohols, which were then separated by column chromatography in an 80 : 20 ratio. The configurations of these major and minor products were identified as ethyl trans- and ethyl cis-2-methyl (or ethyl)-1-hydroxycyclohexylacetate respectively on the basis of their IR analyses, their chromatographic behavior, and correlation with the products of the Grignard reaction, the stereochemistry of which is well known. The NMR spectra of these epimeric alcohols are also discussed, and it is suggested that the chemical shifts of the methylene protons alpha to the ethoxycarbonyl group and of the proton of the hydroxyl group gives useful data for their stereochemical assignments. From these results, it is evident that the Reformatsky and the Grignard reactions proceed in a similar fashion; that is, the entering group predominantly approaches to the carbonyl group from the equatorial side. The stereoselectivity of the Reformatsky reaction is slightly less than that of the Grignard reaction.
Peptide Synthesis by Oxidation-Reduction Condensation. I. Use of NPS-Peptides as Amino Component
Authors: Ueki Masaaki , Maruyama Hiroshi , Mukaiyama Teruaki
Published: July 2006

Sulfenamides were found to react readily with soft nucleophiles in the presence of active hydrogen compounds. A new method for the synthesis of carboxamide from metal carboxylate, sulfenamide and tertiary phosphine was developed. The effects of metal component were examined. Copper(II) salts gave the best result. In a similar way, peptides were synthesized by the reaction of copper(II) salts of acylamino acid, or free acylamino acid in the presence of cupric chloride and triethylamine, with NPS-amino acid derivatives and triphenylphosphine. When organo-mercuric compounds such as dianisylmercury were used in place of cupric chloride and triethylamine in the above reaction, almost complete retention of configuration was observed by the Young test.
Extraction and Spectrophotometric Determination of Copper(II) with 2-Thenoyltrifluoroacetone
Authors: Akaiwa Hideo , Kawamoto Hiroshi , Abe Masanobu
Published: July 2006

A highly sensitive method for the spectrophotometric determination of copper(II) with 2-thenoyltrifluoroacetone (TTA) is described. Copper(II) is extracted with TTA in cyclohexane at pH 5.5 and the residual TTA in the organic phase is removed by washing with sodium hydroxide solution containing pyridine. Pyridine is added to the washing solution so that it forms an adduct and prevents the copper-TTA chelate from decomposing during the alkali treatment process. The absorbance of the organic phase is measured at 340 mμ. Beer’s law is followed over the concentration range of 0.1 to 1.0 μg of Cu per ml, the sensitivity being 0.0023 μg Cu/cm2 at 340 mμ. The present method was applied to the analysis of natural water.
The Nature of a Bond between a Water Molecule and a Protonated Propylene in the Activated Complex for the Acid-catalyzed Hydration of Propylene
Authors: Takaya Haruo , Todo Naoyuki , Hosoya Tadasuke , Minegishi Toshio
Published: July 2006

The nature of a bond between a water molecule and a protonated propylene in the activated complex for the acid-catalyzed hydration of propylene was discussed. The number of water molecules contained in the activated complex, 1.3, was obtained by applying the acidity function, T0, to the dependency of the logk1 on the acid concentration for the hydration of various olefins. The general relationship between the electrostriction and the hydration number of various uni-valent cations was also discussed, and these ions were divided into two separate groups. In the first group, the hydration was caused by electrostatic interaction, while in the second group, the hydration was caused mainly by covalent bond formation. Since the representative point of the hydration of propylene was located near the first group, it was concluded that a molecule of water is held in the activated complex by electrostatic interaction. On the basis of these considerations, the present authors propose a hypothesis which is useful in characterizing the nature of a bond between a water molecule and a protonated substrate in an activated state: (a) If the logk1 for a reaction increases linearly with –H0, a water molecule (or molecules) is held in an activated complex by electrostatic interaction. (b) If the logk1 for a reaction increases linearly with the logma, a water molecule is held in an activated complex by the formation of a covalent bond. k1: the first order rate constant; H0: Hammett’s acidity function; ma: acid concentration.
Analysis of Skeletal Deformation Vibration Spectra in Relation to the Molecular Structure
Authors: Fujiyama Tsunetake
Published: July 2006

Deformation vibrations associated with displacements of skeletal heavy atoms are mainly discussed. It is shown that skeletal deformation vibrations are sensitive to the change of an azimuthal angle θ and that the frequencies of the vibrations are specific for the structure of rotational isomers. The θ-dependency of skeletal deformation vibrations corresponds exactly to that of elements of a kinetic energy matrix \barG. The results emphasize the simplicity and the usefulness of the approximate normal coordinate treatment in which only skeletal heavy atoms are taken into account.
Liquid-phase Adsorption from Binary Solutions on Silica Gel. Separation Factors and Orientation of Adsorbed Components on the Surface
Authors: Kagiya Tsutomu , Sumida Yūzō , Tachi Toshihiro
Published: July 2006

The preferential adsorption equilibria of various binary solutions of cyclohexane-aromatic compounds and cyclohexane-cyclic ethers on chromatographic silica gel have been studied at 30°C. On the basis of the assumption that the adsorption is of the Langmuir-type, the separation factors (α) and the numbers of moles in the adsorbed-phase per unit mass of silica gel (nσ⁄m) have been calculated. The values of logα correlate well not only with the electron-donating properties of the preferentially-adsorbed components, but also with the powers of the gas-phase adsorption on silica gel and of the liquid-liquid interaction with liquid trimethylsilanol. Moreover, on the basis of the information on nσ⁄m, the orientation angles of the adsorbed components on the surface have been evaluated. The adsorption of the aromatic hydrocarbons was nearly flat to the surface, and that of the cyclic ethers, perpendicular.
The Codimerizations of Styrene with Vinyl Compounds Catalyzed by Olefin-palladium(II) Chloride Complexes
Authors: Kawamoto Keiji , Tatani Atsushi , Imanaka Toshinobu , Teranishi Shiichiro
Published: July 2006

The codimerization of styrene with vinyl compounds catalyzed by di-μ-chloro-dichlorobis(styrene)dipalladium(II), (Pd(C6H5CH=CH2)Cl2)2, was investigated in a homogeneous system under mild conditions. The reaction of styrene and methyl acrylate carried out at 50°C for 6 hr yielded 220% codimers, 169% dimers of methyl acrylate, and 18% dimers of styrene, on the basis of the palladium(II) used. The codimerizations of styrene with vinyl acetate and with methyl vinyl ketone gave 50% codimer and 125% codimers respectively. When nitroethylene and n-butyl vinyl ether were used as the vinyl compound, no codimers were formed. The codimerization of styrene-d3 with ethylene was also carried out. The reaction mechanism involving the five-coordinate hydridopalladiumolefin intermediate was proposed and discussed in the terms of the distribution of deuterium in the codimer of styrene-d3 and ethylene, the functional group effects of vinyl compounds, and solvent effects on the codimerization.
The Crystal and Molecular Structure of 2,5-Distyrylpyrazine
Authors: Sasada Yoshio , Shimanouchi Hirotaka , Nakanishi Hachiro , Hasegawa Masaki
Published: July 2006

2,5-Distyrylpyrazine(C20H16N2), which has photo-polymerizability in the crystalline state, crystallizes in the orthorhombic system with cell dimensions of a=20.638, b=9.599, and c=7.655 Å, including four molecules in the unit cell. The space group is Pbca. The structure has been determined by the direct method and refined by the block-diagonal-matrix least-squares method using three-dimensional data. The molecules is not planar; the average plane of the pyrazine ring makes a dihedral angle of 12.09° with that of the benzene ring. The molecules are spaced by the c-translation forming an almost parallel plane-to-plane stack. In this stack, the ethylenic double bonds approach each other at the shortest intermolecular distances of 3.939 Å, since the long axis of the molecule makes an angle of about 30° with the c-axis. Therefore, the polymerization may occur between these double bonds to form a cyclobutane ring.
The Thermal Isomerization of Pinane and Its Products
Authors: Tanaka Juntaro , Katagiri Takao , Ozawa Kiyomi
Published: July 2006

The stereochemistry of the reduced products of the iridenes was studied, and the main product produced by the thermal isomerization from pinane was confirmed to be 1-trans-2-dimethyl-trans-3-isopropenylcyclopentane, unlike as in the literatures. Moreover, the ozonolyses of the iridenes were reexamined in detail, and the following results were obtained: 1) When the ozonides were decomposed with Na2CO3-H2O2, the substituent on C-3 was epimerized. 2) On the other hand, when the ozonides were treated with Zn-CH3COOH, no such epimerization occurred. Consequently, it was found that the former method when used for the confirmation of iridenes, did not give good results for assignments of these compounds.
The Chemistry of Protactinium. IX. A Study of the Solvent Extraction of Protactinium(V) from a Perchloric Acid Solution Using Di(2-ethylhexyl)phosphoric Acid as the Extractant
Authors: Mitsugashira Toshiaki
Published: July 2006

Studies of the chemical behavior of protactinium(V) in a perchloric acid solution were carried out by the HDEHP-benzene extraction method. When the protactinium concentration was lower than 10−7  m, the extraction reaction was considered to proceed as:

PaO(OH)2+aq.+ 3(HA)2 org.= PaOp(OH)qA5−2p−q(HA)2p+q+1 org.+ 2H+aq.+ (2–p–q)H2Oaq.

where p=1, q=0 or 1, and p=2, q=0

and

Pa(OH)32+aq.+ 3(HA)2 org.= PaOp(OH)qA5−2p−q(HA)2p+q+1 org.+ 2H+aq.+ (3–p-q)H2Oaq.

where p=0, q=0, 1, 2, or 3; p=1, q=0 or 1 and p=2, q=0.
The Oligomerization of Butadiene with Nickel Complexes Produced by Means of the Electrolysis of Nickel(II) Chloride
Authors: Ohta Takayuki , Ebina Keisuke , Yamazaki Noboru
Published: July 2006

The oligomerization of butadiene has been found during the electrolysis of solutions containing nickel(II) chloride and electron donors. The oligomerization was affected by the nature of the electron donors used. When the ethanolic solutions of tetrakis(pyridine)nickel(II) chloride or nickel(II) chloride and pyridine with tetra-n-butyl ammonium perchlorate or methanolic solutions without the perchlorate were electrolyzed in the presence of butadiene, a number of linear and dihydrogenated oligomers, with small amounts of branched oligomers, were obtained. The main oligomers were identified as n-octadiene, n-dodecatriene, and n-hexadecatetraene. By adding triphenylphosphine to the reaction system in place of pyridine, n-octatriene and alkoxyoctadiene were catalytically produced instead of hydrooligomers, accompanied by tetrakis(triphenylphosphine)nickel(0). A mechanism involving π-allyl intermediates was proposed for the oligomerization.
The Polymerizations of 2-Vinyl-4-acryloxy-1,3-dioxolane and 2-Vinyl-4-methacryloxy-1,3-dioxolane
Authors: Ouchi Tatsuro , Yokoi Kaneyuki , Yoshimura Kenzi , Oiwa Masayoshi
Published: July 2006

The polymerizations of 2-vinyl-4-acryloxy-1,3-dioxolane(VADO) and 2-vinyl-4-methacryloxy-1,3-dioxolane(VMDO), and the copolymerizations of those divinyl cyclic acetals with styrene (St) and acrylonitrile(AN), have been carried out at 60°C, using 2,2′-azobisisobutyronitrile as the initiator. They were discussed kinetically. The following results were obtained: 1) The polymerizations of the above cyclic acetals containing allylidene and vinyl groups proceeded primarily on the acryl or methacryl group, and the allylidene group was extinguished a little by means of cyclization; the ratios of the rate constant of the unimolecular cyclization reaction to that of the bimolecular propagation reaction of the uncyclized radical were 0.065 mol/l (VADO) and 0.114 mol/l(VMDO). 2) The following monomer reactivity ratios were obtained at 60°C: VADO(M1)-St(M2) r1=0.22, r2=0.81; VADO(M1-AN(M2) r1=0.89, r2=0.95; VMDO(M1)-St(M2) r1=0.51, r2=0.49. The Q and e values of the two monomers were calculated from these values: VADO, Q=0.41, and e=0.65; VMDO, Q=0.81 and e=0.38.
The Elimination Orientation in the Fluoride-promoted Olefin Formation. A Comparison with the Alkoxide-promoted Eliminations
Authors: Ono Noboru
Published: July 2006

When the 2-butyl and 2-pentyl derivatives were treated with tetraethylammonium fluoride in acetonitrile, an olefin-forming elimination took place and an overwhelming Saytzeff orientation was observed. The relative yield of 1-olefin was little affected by changes in the leaving group and β-alkyl group. These results were compared with the results of the eliminations with the conventional base-solvent systems (EtO− in EtOH, t-BuO− in t-BuOH, and t-BuO− in DMSO).
The Synthesis of Methylacetylene by the Pyrolysis of Propylene. VI. The Pyrolysis of Allyl Iodide
Authors: Kunichika Sango , Sakakibara Yasumasa , Taniuchi Mamoru
Published: July 2006

Allyl iodide has been pyrolyzed in a flow system over a wide range of conditions (temperature, 800–1100°C; contact time, 1.44×10−4–14.0×10−4 sec; concentration, 1.8–6.5 mol%; pressure, atmospheric pressure) in order to find suitable conditions for producing methylacetylene and allene and in order to elucidate the reactions of the allyl radical with iodine or the iodine atom at high temperatures. In addition, a study of the mechanism of the pyrolysis of allyl iodide at high temperatures (800–1100°C) has been made. A total yield of allene and methylacetylene of 10 mol per 100 mol of allyl iodide pyrolyzed was obtained under suitable conditions. In the pyrolysis, little cleavage of the C–C bonds of allyl iodide occurred, and propylene, allene, methylacetylene,diallyl, benzene, and an unidentified product were found to be the main products. By means of the zero-conversion method, diallyl alone has been found to be the major product in the early stage of the pyrolysis, while propylene, allene, methylacetylene, and benzene have been found to be the chief products at higher conversions. On the basis of the observed results, a free-radical mechanism has been proposed for the main reactions. It has further been concluded that the pyrolysis is a radical decomposition initiated by the C3H5I → C3H5·+I reaction and that the overall mechanism in the early stage of the pyrolysis may be represented essentially by the 2C3H5I → C6H10+I2 reaction.
Studies of the Thiocarbonyl Compounds. III. The Mechanism of the Thermal Rearrangement of Aryl Thionocarboxylates
Authors: Kaji Aritsune , Araki Yoshiaki , Miyazaki Koshin
Published: July 2006

The thermal rearrangement of aryl thionocarboxylates was kinetically investigated in diphenyl ether. The rate constants of the rearrangement of aryl N,N-dimethylthionocarbamates were well correlated with the σ− values, but the plots of the electron-releasing para-substituents deviated slightly on the lower side of the meta correlation line. A good linear free-energy relationship existed between the rearrangement of aryl N,N-dimethylthionocarbamates and the bimolecular nucleophilic reaction of 4- or 5-substituted 1-chloro-2-nitrobenzenes with piperidine. By the use of the substituent constants obtained from the latter reaction for the electron-releasing para-substituent constants, a fairly good ρ–σ− relationship was obtained. Linear free-energy relationships also existed between the rearrangements of aryl N,N-dimethylthionocarbamates and aryl thionobenzoates, and between the rearrangements of aryl N,N-dimethylthionocarbamates and O-aryl S-phenyl dithiocarbonates. The order of the reaction constants was in accord with that of the inductive effects of the α-substituents of the thiocarbonyl group, so the electron-releasing conjugative effects of the α-substituents of the thiocarbonyl group did not play important roles in the rate-determining step. The present results indicate that the thermal rearrangement of aryl thionocarboxylates is an intramolecular SN–Ar which involves a four-membered cyclic transition state formed by a nucleophilic attack of the lone-pair electrons of the thiocarbonyl sulfur atom on the migrating aromatic ring.