bluuebunny/crossref_metadata_2025 huggingface dataset:
Versatile Synthesis of Dialkyl Cyclopropylphosphonates via Reductive Phosphonation
Authors: Hirao Toshikazu , Hagihara Masahiko , Agawa Toshio
Published: July 2006

Reductive phosphonation of gem-dibromocyclopropanes was accomplished by the reaction with trialkyl phosphites, triethylamine, and water affording dialkyl cyclopropylphosphonates. This unique transformation proceeds by the virtue of trialkyl phosphites and dialkyl phosphonates.
Isolation and Structures of Euphohelins, New Toxic Diterpenes from Euphorbia Helioscopia L.
Authors: Kosemura Seiji , Shizuri Yoshikazu , Yamamura Shosuke
Published: July 2006

Five new toxic diterpenes, euphohelins A, B, C, D, and E, have been isolated from the plant Euphorbia helioscopia L., and their stereostructures have also been elucidated on the basis of their spectral data coupled with some chemical evidence: euphornin, the known toxic diterpene, has been successfully converted into euphohelin A.
Photochemical Ring-expansion Reaction of 1,2-Benzisothiazolinones
Authors: Kamigata Nobumasa , Hashimoto Satoshi , Kobayashi Michio , Nakanishi Hiroshi
Published: July 2006

The photochemical reaction of a series of 2-aryl-1,2-benzisothiazol-3(2H)-ones (1) under deaerated conditions was found to give dibenzo[b,f][1,4]thiazepin-11(10H)-ones (2). A mechanism through a biradical species is proposed for the photoreaction. When the photolysis of 1 was carried out in the presence of oxygen, 2-aryl-1,2-benzisothiazol-3(2H)-one 1-oxides (11) were formed together with compounds 2.
Interaction of Galvinoxyl Radical with Ascorbic Acid, Cysteine, and Glutathione in Homogeneous Solution and in Aqueous Dispersions
Authors: Tsuchiya Jyunichi , Yamada Teruaki , Niki Etsuo , Kamiya Yoshio
Published: July 2006

The rates of interaction of galvinoxyl radical with ascorbic acid, cysteine, and glutathione have been studied in homogeneous solution and in water dispersions as a model reaction of vitamin E radical with these reducing agents in biological systems. The rate was measured by following the disappearance of galvinoxyl radical with absorption spectroscopy and electron spin resonance. In every system, galvinoxyl reacted with these reducing substrates and their relative reactivities decreased in the order of ascorbic acid>cysteine>glutathione. For any reducing substrate, the rate was fastest in homogeneous solution and slowest in micelle in Triton X-100 aqueous solution, and the rate in liposome system was in between.
Reactivities of Stable Rotamers. XVI. Tributylstannane Reduction and Electron-impact Mass Spectra of Rotamers of 1,2,3,4-Tetrachloro-9-(2-chloro-1,1-dimethylethyl)triptycene and 1,2,3,4-Tetrachloro-9-(2-chloro-1-chloro-methyl-1-methylethyl)triptycene
Authors: Yonemoto Katsumi , Kakizaki Fumihiko , Yamamoto Gaku , Nakamura Nobuo , Oki Michinori
Published: July 2006

1,2,3,4-Tetrachloro-9-(2-chloro-1-chloromethyl-1-methylethyl)triptycene (1) and 1,2,3,4-tetrachloro-9-(2-chloro-1,1-dimethylethyl)triptycene (2) were reduced with tributylstannane in the presence of azobisisobutyronitrile in benzene. 1 was reduced to 2 which was further converted to a 9-t-butyltriptycene under the conditions. The chloromethyl group sc to the peri-chloro substituent was found to be ca. 7 times more reactive than the ap in sc-1. sc-2, was consumed 1.7 times more rapidly than ap-2. The results are attributed to the participation of the peri-chloro substituent in the chlorine abstraction. Electron impact mass spectra of these compounds reveal that they give different intensities at a number of peaks. The difference is again attributed to the chloro participation in stabilizing the cation formed.
Preparation of Pyrido- and Azepino-fused Cycl[3.2.2]azines
Authors: Noguchi Michihiko , Tanigawa Noriyuki , Kajigaeshi Shoji
Published: July 2006

Pyrido- and azepino-fused cycl[3.2.2]azines were obtained by the reaction of the corresponding pyrido- and azepino[hi]indolizines with electron-deficient acetylenes in the presence of appropriate oxidants. The reaction pathway of their preparation was proposed to be a sequence of Michael addition of indolizine to acetylene, 10π-electrocyclic reaction of Michael adduct, and dehydrogenation by means of the chemical conversions of the isolated intermediates.
Kinetic Study of the Thermal Decomposition of Isocyanic Acid in Shock Waves
Authors: Kajimoto Okitsugu , Kondo Osamu , Okada Kazuo , Fujikane Jiro , Fueno Takayuki
Published: July 2006

Thermal decomposition of isocyanic acid HNCO diluted to less than 2.0 mol% in argon was studied behind incident shock waves over the temperature range 2100–2500 K. The decomposition course was followed by monitoring the light absorption of HNCO and NH(3Σ−) at 206 and 336 nm, respectively. It is confirmed that the primary step of the decomposition is a bimolecular process HNCO+Ar→NH(3Σ−)+CO+Ar, ΔH°0=337 kJ mol−1, with the low-pressure limit rate constants k=1017.23±0.36exp[−(402±17) kJ mol−1/RT] cm3 mol−1 s−1. The siglet-to-triplet crossing point is estimated on the basis of the RRKM low-pressure-limit rate constant calculations. The overall decomposition mechanism is suggested and its validity is confirmed by computer simulation of the time–concentration profiles of NH(3Σ−) at varying temperature.
The Synthesis and Thermal Behavior of Barium Bis(hydrogenphosphoramidate) and Barium Phosphoramidate
Authors: Sato Shoji , Watanabe Makoto
Published: July 2006

Barium bis(hydrogenphosphoramidate) monohydrate and barium phosphoramidate monohydrate were made by mixing a solution of potassium hydrogenphosphoramidate and a solution of barium chloride at pH 6.1–6.4 and 10.0–10.5 respectively. Both products were stable at room temperature. Barium bis(hydrogenphosphoramidate) monohydrate was decomposed by water to produce the orthophosphate. This was condensed to make polyphosphates above 100 °C and finally formed barium metaphosphate above 500 °C. The thermal products of the hydrogenphosphoramidate did not produce any phosphate with imino groups. Barium phosphoramidate produced ortho-, di-, imidodi-, and triphosphates when it was heated above 200 °C. These thermal products were converted to dibarium diphosphate in air above 500 °C.
Solvent Effect on Adsorption of TCNQ onto Metal Oxides
Authors: Esumi Kunio , Miyata Kazuaki , Meguro Kenjiro
Published: July 2006

7,7,8,8-Tetracyanoquinodimethan(TCNQ) was adsorbed on the surfaces of alumina and titania from three basic solvents. The amount of TCNQ adsorbed decreased with an increase in the acid-base interaction between TCNQ and the basic solvent for both metal oxides. The TCNQ anion radicals were formed as a result of electron transfer from the metal oxide surfaces to adsorbed TCNQ. Further, the concentration of TCNQ anion radicals formed on the oxides after the TCNQ adsorption decreased also with an increase in the acid-base interaction between TCNQ and the basic solvent.
Preparation and Properties of Oligocytidylates with 2′–5′ Internucleotide Linkage
Authors: Sawai Hiroaki , Ohno Masaji
Published: July 2006

Oligocytidylates upto a pentamer were prepared by lead(II) ion catalyzed polymerization of cytidine 5′-phosphorimidazolide in aqueous solution. 2′–5′ internucleotide linkage was preferentially formed. The yields of the 2′–5′ linked dimer, trimer, tetramer and pentamer were 17.0, 5.5, 1.9, and 0.7%, respectively. Some of their properties were studied by NMR, CD, UV, and chromatography and compared with the corresponding 3′–5′ linked oligomers which were prepared enzymatically.
Potential Energies of Rotation of Double Bond in Ethylene Molecule and Ion
Authors: Ichikawa Hiroshi , Ebisawa Yukiko , Shigihara Atsushi
Published: July 2006

MP3/6-31G** calculations show that the potential barrier of a double-bond rotation in an ethylene ion is 137 kJ mol−1 (about half that of the molecular state) and that the orthogonally twisted ion has a C2v symmetry. The geometries are discussed in relation to the total energies.
Strong Embedding Effect of Decalin Walls on Cation Complexation in Crown Ethers
Authors: Kobiro Kazuya , Takahashi Mitsuru , Takada Shigeki , Odaira Yoshinobu , Kawasaki Yoshikane
Published: July 2006

Cylindrical crown ether, tridecalino-18-crown-6, shows strong embedding effect toward coordinated thallium ion.
Reaction of Leucomalachite Green with Chloranil
Authors: Nishimura Norio , Motoyama Takushi
Published: July 2006

The reaction of Leucomalachite Green with chloranil to produce Malachite Green cations has been carried out in acetonitrile. Prior to the formation of the cations, a 1:1 CT complex is formed between the reactants. The equilibrium and the rate constants were estimated.
A Kinetic Study of Thermal Rotational Isomerization of 5,10,15,20-Tetrakis(o-aminophenyl)porphyrin and 5,10,15,20-Tetrakis(o-pivaloylaminophenyl)porphyrin
Authors: Hatano Keiichiro , Anzai Kazunori , Nishino Akemi , Fujii Keiko
Published: July 2006

Rates of thermal interconversion of atropisomers of 5,10,15,20-tetrakis(o-aminophenyl)porphyrin and 5,10,15,20-tetrakis(o-pivaloylaminophenyl)porphyrin have been determined.
Palladium-catalyzed Reaction of Stannyl Sulfide with Aryl Bromide. Preparation of Aryl Sulfide
Authors: Kosugi Masanori , Ogata Toshimi , Terada Masahiro , Sano Hiroshi , Migita Toshihiko
Published: July 2006

Tributylstannyl alkyl or aryl sulfide and bis(tributylstannyl) sulfide were found to be useful to prepare aryl sulfides in good yields under the usual conditions of the palladium-catalyzed reaction with aryl bromides.
Ternary Coordination Complexes Formed by Copper(II) with Thio-or Dithiodialkanoic Acids and Some Selected Ethyl-substituted Malonic Acids
Authors: Shelke D N
Published: July 2006

Binary and ternary complexes formed by copper(II) with thio- or dithiodialkanoic acids and ethyl-substituted malonic acids have been investigated potentiometrically in an aqueous solution and the relevant stability constants have been evaluated using computer technique. Thio- and dithiodialkanoic acids were thiodiacetic, dithiodiacetic, 3,3′-thiodipropionic, and 3,3′-dithiodipropionic acids. The results are discussed in terms of substituent influences upon the chelation of the malonate dianions to the systems copper(II)-thiodialkanoic acids. It is suggested that in the mixed copper chelates containing thiodiacetic acid, the geometrical characteristics of the more basic ligand, governs the coordination of the other ligand.
Phase Relations in the System NH4Ti2P3O12–NH4Zr2P3O12
Authors: Ono Akira
Published: July 2006

Crystalline phases in the system NH4Ti2P3O12–NH4Zr2P3O12 were prepared in a high pressure vessel, and were investigated by X-ray method. New compounds, (NH4)1+xTi3+x(Ti4+,Zr)2−xP3O12 (1≥x), with the langbeinite-type structure were produced under reducing conditions.
Synthesis of 2,6,8-Trinitro-4H-cyclopenta[def]phenanthren-4-one as an Electron Acceptor
Authors: Minabe Masahiro , Yoshida Masaaki , Kimura Okitoshi
Published: July 2006

2,6,8-Trinitro-4H-cyclopenta[def]phenanthren-4-one (TNC) was synthesized by the nitration of the parent ketone. TNC formed charge-transfer complexes with polycyclic aromatic hydrocarbons (PAH). The property of TNC as an electron acceptor was compared with that of 2,4,7-trinitro-9H-fluoren-9-one (TNF). TNC was found to be a better complexing agent than TNF.
119Sn NMR Spectroscopic Determination of Diastereomeric Ratio of Some Optically Active Organotin Compounds
Authors: Otera Junzo , Yano Toru
Published: July 2006

Diastereomeric ratio of optically active organotin compounds, R2*SnX2 and R1R2R3SnR*, was successfully determined by means of 119Sn NMR spectra.
The Facile Synthesis of Unsymmetrical Ketones Using Acetone Dimethylhydrazone
Authors: Yamashita Masakazu , Matsumiya Kaoru , Tanabe Minako , Suemitsu Rikisaku
Published: July 2006

Unsymmetrical ketones were prepared by successive alkylation of acetone dimethylhydrazone. Application of this reaction to the synthesis of dihydrojasmone is described.
Solvent Effects on Chemical Reactivities of Conjugated Molecules
Authors: Ohmae Takayuki
Published: July 2006

The propagator method is applied to the study of solvent effects on chemical reactivities of conjugated molecules. It is shoen that the number of π-electrons of a solute molecule (a conjugated molecule) controls the solvent effects on chemical reactivities. The obtained theory is applied to the study of solvent effects on selectivities of pericyclic reactions.
Charge-transfer Complexes, Gas-liquid Chromatographic and Photochemical Characteristics, and Solvent Adducts of Polyphenylenes and Related Linear Polyphenylsls
Authors: Fujioka Yasuhiro
Published: July 2006

The absorption spectra of the charge-transfer (CT) complexes formed by two acceptors (tetracyanoethylene and 2,3-dichloro-5,6-dicyano-p-benzoquinone) with thirteen macrocyclic polyphenylenes and with thirty-eight linear polyphenyls were measured in dichloromethane. A linear relationship existing between the first transitions of the CT-complexes and those of the uncomplexed donor hydrocarbons made it possible to predict the CT-bands of new polyphenylenes and polyphenyls. By the gas-liquid chromatography using a glass capillary column, forty-nine polyphenyls and polyphenylenes, containing a large number of isomers, were successfully analyzed. The relationship between the retention times and the structure of linear polyphenyls was expressed by means of a simple empirical equation, and the equation was also applicable to the polyphenylenes by adding a correction factor. These equations are extremely useful for the estimation of the retention time and elution order and the structure of unknown polyphenyls and polyphenylenes. The reductive irradiation of m,m,o,p,o-pentaphenylene provided the bridged annulene compound. For six polyphenylenes and the related compounds, the criteria for the occurrence of the intramolecular photocoupling reaction were discussed. Among the examined polyphenylenes, m,o,o,m,o,o-hexaphenylene and o,p,p,o,p,p,o,p,p-nonaphenylene formed the adducts with several solvents.
Molecular Design of Crown Ethers. 3. Extraction of Alkaline Earth and Heavy Metal Picrates with 14- to 17-Crown-5 and 17- to 22-Crown-6
Authors: Inoue Yoshihisa , Ouchi Mikio , Hakushi Tadao
Published: July 2006

The solvent extraction of alkaline earth and heavy metal picrates with a series of ring-contracted and ring-enlarged crown ethers has been carried out in order to reveal the effects of methylene-chain length upon cation-binding ability. Compared with the parent 3m-crown-m, the ring-contracted crown ethers and their sila analogues possess limited extractabilities, often as low as those for the corresponding glymes. On the other hand, the ring-enlarged crown ethers, in general, show gradual, but not drastic, decreases in extractability for most cations with increasing methylene-chain length. Interestingly, the extractabilities for Ag+, Tl+, and Ba2+ do not decrease monotonously with ring expansion; in particular 16-crown-5 is a better extractant for Ag+ than 15-crown-5 and even than 18-crown-6. These results are accounted for in terms of cavity size, conformation, and molecular symmetry of crown ethers. Effects of cation hydration upon extractability and the limitations of solvent extraction technique are also discussed.
Synthesis and Properties of Gramicidin S Analogs Containing d-Phe–l-Pro–d-Val or l-Phe–l-Pro–d-Val Sequences in Place of d-Phe–l-Pro–l-Val Sequence in the β-Turn Part of the Antibiotic
Authors: Tamaki Makoto , Okitsu Tadashige , Araki Mie , Sakamoto Honami , Takimoto Michiaki , Muramatsu Ichiro
Published: July 2006

In order to investigate the contribution of configurations of amino acid residues around Pro residues in gramicidin S to its activity and conformation, [d-Val1,1′]- and [d-Val1,1′  l-Phe4,4′]-gramicidin S were synthesized by a liquid-phase method. The CD spectra of these analogs and gramicidin S in aqueous solutions differ from each other, indicating that these peptides have different conformations. These analogs have practically no activity against the Gram-positive microorganisms tested, indicating the importance of the presence of the d-Phe–Pro–Val sequence in gramicidin S regarding activity.
The Spin Exchange of Nitroxide Radicals with Ni2+ Ions in SDS Micellar Solutions
Authors: Aizawa Masayuki
Published: July 2006

The spin-exchange rate of three kinds of hydrophobic nitroxide radicals with paramagnetic ions, Ni2+ ions, was measured in an aqueous sodium dodecyl sulfate (SDS) micellar solution at 30 °C. In the presence of SDS micelles, two of the three radicals had their spin-exchange rates accelerated, whereas the rate of the other radical was deaccelerated. These strange results were interpreted on the basis of a different solubilized location of the radicals in SDS micelles. The translational mobility of the Ni2+ ions on a micellar surface was estimated from the spin-exchange rate in the accelerated systems.
Theory of Time-resolved Resonance Raman Scattering from Vibrationally Hot Molecules
Authors: Fujimura Yuichi , Ohtsuki Yukiyoshi , Nakajima Takeshi
Published: July 2006

A theory of time-resolved resonance Raman scattering (RRS) from molecules is developed. The time-resolved RRS cross section is defined as a product of the time-dependent vibronic energy distribution and the scattering cross section from the single vibronic level. The theory is applied to the time-resolved RRS from vibrationally hot molecules whose vibronic distribution characterized by a canonical distribution with temperature higher than that of the heat bath relaxes to the equilibrium one in the presence of a collisional vibrational relaxation. Analytical expressions for the time-resolved RRS cross section are derived within a displaced harmonic oscillator model. It is shown that in the strong coupling case the intensities of the Stokes and anti-Stokes Raman bands in the rigorous resonance case vary inversely as the time-dependent average vibrational occupation number. Some model calculations are performed to illustrate the time-dependent intensity changes of the Raman bands.
Delayed Fluorescence of Zinc Porphyrin in Poly(vinyl alcohol) Film
Authors: Ohno Osamu , Kaizu Youkoh , Kobayashi Hiroshi
Published: July 2006

The delayed fluorescence was observed at room temperature with tetrakis(4-sulfophenyl)porphinatozinc (ZnTPPS4) dyed on poly(vinyl alcohol) (PVA) film. In the film, the T-T annihilation is prohibited since any two molecules in the excited triplet can not encounter during their lifetime. Three types of luminescence emission were observed; fluorescence (S1→S0), phosphorescence (T1→S0) and delayed fluorescence (T1\ightsquigarrowS1→S0). The delayed fluorescence can be detected only at elevated temperatures where thermal activation from the lowest excited triplet can repopulate the lowest excited singlet.
Crystal Structure of Nonstoichiometric Tetranuclear Platinum Compound, cis-Diammineplatinum α-Pyrrolidone Violet, [Pt4(NH3)8(C4H6NO)4](PF6)2(NO3)2.56·5H2O
Authors: Matsumoto Kazuko
Published: July 2006

Nonstoichiometric platinum tetranuclear compound, cis-Diammineplatinum α-Pyrrolidone Violet, [Pt4(NH3)8(C4H6NO)4)(PF6)2(NO3)2.56·5H2O, has been synthesized and the crystal structure has been solved with X-ray diffraction analysis. The crystal is triclinic with the space group of P\bar1 and cell dimensions of a=13.530(8), b=19.242(9), c=10.222(3) Å, α=96.56(9), β=93.82(9), γ=74.64(8)°, V=2547.4 Å3, and Z=2. The structure have been solved by heavy atom method and the final discrepancy index R1 was 0.094 and R2 was 0.090. The cation is structurally identical with those of cis-Diammineplatinum α-Pyridone Yellow(PPY), [Pt4(NH3)8(C5H4NO)4]4+, cis-Diammineplatinum α-Pyridone Blue(PPB), [Pt4(NH3)8((C5H4NO)4]5+, and cis-Diammineplatinum α-Pyrrolidone Tan(PPT), [Pt4(NH3)8(C4H6NO)4]6+, and consists of four platinum atoms linked in a chain with bridging pyrrolidone ligands. Each platinum atom is cis coordinated by two ammine ligands and either two exocyclic oxygen atoms or two deprotonated ring nitrogen atoms of α-pyrrolidone ligands. The Pt-Pt bond distances are 2.848(2), 2.875(2), 2.839(2), and 2.875(2) Å, which are intermediate between those of PPY and PPB, indicating that the average platinum oxidation state is between 2.0 and 2.25. According to the potentiometric: oxidative titration of the compound using Ce(IV), the average platinum oxidation state is 2.14 and therefore the compound is considered to consist of 44% of [Pt4(NH3)8(C4H6NO)4]4+ and 56% of [Pt4(NH3)8(C4H6NO)4]5+.
Synthesis of 6-Alkylpurine Derivatives by Nickel-complex-catalyzed Coupling Reaction of 6-(Methylthio)purine Derivatives with Grignard Reagents
Authors: Sugimura Hideyuki , Takei Hisashi
Published: July 2006

6-(Methylthio)purine reacted with RMgX (R=C6H5, CH3(CH2)nCH2 (n=2 to 6), C6H5CH2CH2, (CH3)2 C=CHCH2CH2) in the presence of 5 mol% [NiCl2(Ph2PCH2CH2CH2PPh2)] in refluxing THF for 8 h to afford 6-aryl or 6-alkylpurines in 62–74% yields. By applying this reaction to 6-(methylthio)purine nucleoside, 6-(4-methyl-3-pentenyl)-9-β-d-ribofuranosylpurine was synthesized.
Preparation, Properties, and Analytical Applications of Crystalline Tin(IV) Tungstoselenate
Authors: Nabi Syed Ashfaq , Siddiqi Zia Mahmood
Published: July 2006

Synthesis of tin(IV) tungstoselenate has been done under a variety of conditions. The effects of mixing ratio of reagents and the pH of the mixture on the properties of the material have been studied. The crystalline sample of tin(IV) tungstoselenate has been chosen for detailed studies, such as chemical and thermal stabilities, chemical composition, pH-titrations, IR and X-ray analyses. On the basis of above studies a tentative formula has been proposed for tin(IV) tungstoselenate. The adsorption behaviour of metal ions in different concentrations of perchloric acid has been studied. On the basis of Kd values few analytically important separations of metal ions have been achieved on small columns of tin(IV) tungstoselenate.
The Unusually Strong Effect of a 4-Cyano Group upon Electronic Spectra and Dissociation Constants of 3-Substituted 7-Hydroxycoumarin
Authors: Wolfbeis Otto S , Koller Ernst , Hoghmuth Petra
Published: July 2006

Synthesis, absorption and fluorescence spectra as well as pKa values of 7-hydroxycoumarins with electron-withdrawing substituents in positions 3 are described. Introduction of a 4-cyano group is achieved by oxidative cyanation of coumarins using potassium cyanide and elemental bromine. 7-Hydroxycoumarins without a 4-cyano group are useful indicators for measuring physiological pH values due to their intense fluorescences, longwave absorptions and emissions, as well as pKa values of around 7. The presence of a 4-cyano group gives rise to a dramatic longwave shift in absorption (30–40 nm in methanol) and emission (55–80 nm). In water solution, the fluorescence maxima are at around 570–600 nm, with excitation maxima between 410 and 510 nm, depending on whether the phenol or phenolate species is excited. For all coumarins under investigation, fluorescence is from the anion form even in the pH 2–7 range. This phenomenon is interpreted in terms of excited state dissociation according to the Forster model. The interpretation is corroborated by calculations of the excited state pKa values, which show them to be lower by 4.5–6.4 units than those of the ground state.
Aromatic Systems with 10π Electrons Derived from 3a-Azapentalene. Part 40. Studies on the 1,2,4-Triazolo[4,3-b][1,2,4]triazole Series
Authors: Alajarin Mateo , Molina Pedro , Tarraga Alberto , Vilaplana M Jesús , Foces-Foces M de la Concepción , Hernandez Cano Felix , Claramunt Rosa M , Elguero Jose
Published: July 2006

The synthesis, structure, and reactivity of several 1,2,4-triazolo[4,3-b][1,2,4]triazole derivatives have been studied. Structures have been established throughout a careful carbon-13 NMR study, and for the most unusual one (inner salt of 2-methyl-3-methylthio-6-phenyl-7H-1,2,4-triazolo[4,3-b][1,2,4]triazolium hydroxide) by X-ray crystallography: the space group is P21/c, the cell constants are a=12.6939(5), b=16.0936(6), c=12.0239(5) and β=107.247(3)° and Z=8. The S-methyl group is directed towards the fusion of the five-membered rings at +/−syn conformations. The azapentalene moieties have the first atoms of the substituents on its plane and the 6-phenyl rings make an angle of −26.7 and −4.3° with it, in the two independent molecules respectively.
Elimination Reaction of Aldehydo-d-glucurono-6,3-lactone Derivatives
Authors: Itoh Hiroshi , Aoki Koichi , Matsumoto Takahiro
Published: July 2006

d-Glucurono-6,3-lactone derivatives are converted to butenolide or dihydro-2H-pyran derivatives by treatment with triethylamine.
The Raman Spectra of Cobalt(III) Complexes. V. Differentiation between Two cis(a) Isomers of [Coa2(NH3)2(en)] Type Complexes (a=NO2− and CN−)
Authors: Kanamori Kan , Bansho Ikuko , Kawai Kiyoyasu , Akamatsu Keiji , Shimura Yoichi
Published: July 2006

Three geometrical isomers of [Co(NO2)2(NH3)2(en)]+ were newly prepared. Two cis(NO2) isomers (trans(NH3) and cis,cis) were clearly differentiated on the basis of the polarizabilities of the Raman bands due to Co–N(NH3 and en) stretching vibrations. The Raman polarization measurement was also applied successfully to the determination of the geometrical configurations of two [Co(CN)2(NH3)2(en)]+ isomers. The structural assignments were substantiated by optical resolution of the cis,cis isomers of [Coa2(NH3)2(en)]+ (a=NO2− and CN−).
Nonacarbonyldiiron-, Pentacarbonyliron-, or Hexacarbonylmolybdenum-induced Reactions of 4,5-Polymethylene-substituted 2-Isoxazolines
Authors: Nitta Makoto , Yi Akihiro , Kobayashi Tomoshige
Published: July 2006

The reaction of 4,5-polymethylene-substituted 2-isoxazolines, 3-phenyl-3a,5,6,7a-tetrahydro-4H-pyrano[3,2-d]isoxazole or 3-phenyl-3a,4,5,6a-tetrahydrofuro[3,2-d]isoxazole, with [Fe2(CO)9], [Fe(CO)5], or [Mo(CO)6] resulted in the formation of 5-hydroxy-1-phenyl-1-pentanone or 4-hydroxy-1-phenyl-1-butanone, via the N–O and C–C bond cleavage of the 2-isoxazoline ring and the subsequent hydrolysis. The similar reaction of 7a-morpholino- and 7a-(1-pyrrolidinyl)-3-phenyl-3a,4,5,6,7,7a-hexahydro-1,2-benzoisoxazoles undergoes the N–O bond cleavage and, the subsequent elimination of the amino group or the C-3a–C-7a bond fission. Although the reaction of 6a-morpholino- and 6a-(1-pyrrolidinyl)-3-phenyl-3a,4,5,6a-tetrahydro-4H-cyclopent[d]isoxazoles with [Mo(CO)6] undergoes the N–O bond cleavage, and the subsequent elimination of the amino group or the C-3a–C-6a bond fission, the reaction of those 2-isoxazolines with [Fe2(CO)9] proceeds very slowly. The mechanisms are proposed for these reactions.
The Cyclodextrin–Quinone Inclusion Compounds in an Aqueous Solution at 77 K. II. 9,10-Phenanthrenequinone and Acenaphthenequinone
Authors: Kuboyama Akira , Matsuzaki Sanae Y
Published: July 2006

A complex formation between cyclodextrins (CD’s) and the two o-quinones (9,10-phenanthrenequinone (PHQ) and acenaphthenequinone (ANQ)) in a water–ethylene glycol 1 : 1 mixture glassy solution at 77 K was investigated using the nπ* phosphorescence spectra of these quinones. It was considered on the basis of the observed results that PHQ forms a 1 : 1 complex with γ-CD and ANQ a 2 : 1 complex with β-CD. The structures of these complexes are discussed. It was found that complexes between γ-CD and the PHQ– and ANQ– naphthalene charge-transfer complexes are also formed.
The Crystal and Molecular Structure of Tetrakis(μ-1-hydroxy-2-naphthoato)-bis{aqua(ethanol)(1-hydroxy-2-naphthoato)neodymium(III)}-Water–Ethanol (1/2/2), [{Nd[C10H6(OH)(COO)]3(H2O)(C2H6O)}2]·2H2O·2C2H6O
Authors: Ohki Yoshiyuki , Suzuki Yasuo , Takeuchi Toshio , Shimoi Mamoru , Ouchi Akira
Published: July 2006

The structure of the title complex was determined by the single-crystal X-ray-diffraction method. It is triclinic, with the space group P\bar1; the cell constants were a=12.529(2), b=15.044(4), c=10.063(1) Å, α=104.15(2), β=98.73(1), and γ=87.16(2)°; Z=1, and the final R value was 0.053. The central metal atom is in a tricapped trigonal-prism geometry and is ennea-coordinated with seven oxygen atoms of the carboxylate ligands and with each oxygen atom of one water and one ethanol molecule. The complex is dimeric and the metal atoms are bridged with four carboxylate ions; two of them act as bidentates, and the other two, as tridentates, where one oxygen atom is coordinated to both metal atoms. The other carboxylate ion makes a chelate ring with each metal atom. The dimer is connected through hydrogen bondings to the atoms on both sides along the c-axis.
Transformation of 3-(2,2-Dichloroethenyl)-2,2-dimethylcyclopropanecarboxylates to the Corresponding 2,2-Dibromoethenyl Analogs by Halogen Exchange Reaction
Authors: Matsui Kiyohide , Saito Akemi , Kondo Kiyosi
Published: July 2006

The title transformation is effected with aluminium tribromide or related reagents in over 80% yields without cis-trans isomerization or epimerization. Efficient removal of hydrogen bromide is essential for optimum yields of the desired products. Use of boron tribromide instead of aluminium tribromide results in opening of the cyclopropane ring with no halogen exchange.
Active Carbon-Supported Aluminium Copper(I) Chloride as Solid Carbon Monoxide Adsorbent
Authors: Hirai Hidefumi , Wada Keiichiro , Komiyama Makoto
Published: July 2006

Active carbon-supported aluminium copper(I) chloride (AlCuCl4) is prepared by mixing active carbon with toluene solution of AlCuCl4, followed by the removal of the liquid phase at 6 mmHg, 100 °C. The active carbon-supported AlCuCl4 rapidly adsorbs carbon monoxide (CO) at 20 °C under 1 atm from 9:1 CO–N2 mixture and the equilibrium molar ratio of adsorbed CO to AlCuCl4 is 1.03. Adsorbed CO is desorbed either by reducing pressure or by elevating temperature. In the second adsorption, which is carried out after the desorption at 6 mmHg, 20 °C for 10 min, the molar ratio of adsorbed CO to AlCuCl4 is 0.51. The molar ratios are constant at 0.51 in the third and later adsorptions. The CO adsorbing ability of the active carbon-supported AlCuCl4 remains virtually unchanged on repeated contacts with nitrogen gas containing 9000 ppm of water.
Polymer-Protected Metal Complex for Gas Separation. II. Cross-Linked Polystyrene-Supported Aluminium Copper(I) Halide as Solid Carbon Monoxide Adsorbent
Authors: Hirai Hidefumi , Hara Susumu , Komiyama Makoto
Published: July 2006

Macroreticular (MR) type cross-linked polystyrene-supported aluminium copper(I) chloride is prepared by refluxing MR type polystyrene (divinylbenzene content 20%), aluminium chloride, and copper(I) chloride in benzene, toluene, carbon disulfide, or dichloromethane, followed by evaporation of the liquid phase. All the polystyrene-supported aluminium copper(I) chloride exhibit rapid and reversible adsorptions of carbon monoxide (CO). For the adsorbent prepared by using toluene as solvent, the equilibrium molar ratio of adsorbed CO to the charged copper(I) chloride is 0.83 at 20 °C under 1 atm (initial partial pressure of CO: 0.90 atm). Desorption of CO is carried out at 7 mmHg, 20 °C for 10 min. The equilibrium molar ratio of adsorbed CO to the charged copper(I) chloride in the second adsorption is 0.56. In the following adsorptions, the equilibrium molar ratios are virtually constant at 0.56. Usage of either gel type cross-linked polystyrenes or a linear polystyrene in place of the MR type cross-linked polystyrene results in CO adsorbents having poor abilities with respect to both adsorption rates and capacities. The adsorbing capacities of the CO adsorbents prepared from aluminium halide, copper(I) halide, and the MR type cross-linked polystyrene decrease as follows: AlCl3–CuCl system>AlBr3–CuBr system>>AlI3–CuI system≈AlCl3–CuI system≈AlI3–CuCl system≈0.
Electronic Properties of Black Phosphorus Single Crystals and Intercalation Compounds
Authors: Maruyama Yusei , Suzuki Setsuko , Osaki Tomoko , Yamaguchi Hizuru , Sakai Sumiko , Nagasato Kyoko , Shirotani Ichimin
Published: July 2006

Actual procedures for the preparation of black phosphorus single crystals by a bismuth flux method have been explored and the details are described. The anisotropy and the temperature dependence of the electrical conductivity and the Raman scattering spectra of the crystals obtained by the above-method have been measured. The reflection spectra of crystals which were prepared by a high pressure technique have also been observed and compared with the calculated data. Several preliminary attempts for synthesizing black phosphorus intercalation compounds have been carried out for the first time. Evidence for the intercalation by an X-ray analysis is presented.
ESR and Mössbauer Studies of Crystallization Process of Iron Phosphate Glass
Authors: Tanaka Katsuhisa , Soga Naohiro , Ota Rikuo , Hirao Kazuyuki
Published: July 2006

0.7Fe2O3–0.3P2O5 glass was prepared by using a twin-roller method and the crystallization process of this glass was followed by means of ESR and Mössbauer spectroscopy in order to understand the state and the behavior of iron ions in the glass. The ESR line shape of the quenched 0.7Fe2O3–0.3P2O5 glass was much broader than that of the crystallized glass heat-treated at 710 °C for 5 h. Moreover, the linewidth of Mössbauer spectra decreased monotonously through the crystallization process. These facts indicated that there existed a distribution of ligand fields around iron ions in the glass. The Mössbauer parameters, that is the isomer shift and the quadrupole splitting, of the 0.7Fe2O3–0.3P2O5 glass showed that Fe3+ ions in this glass were laid on distorted octahedral ligand fields. The magnetic interaction working in the 0.7Fe2O3–0.3P2O5 glass at room temperature was dipole–dipole interaction. Besides, the Mössbauer spectrum of the glass exhibited no internal field line at room temperature. Hence, the glass is considered paramagnetic at room temperature. At the first stage of crystallization process, the α-Fe2O3 particles precipitated were sufficiently small and so the specimen was superparamagnetic, as revealed from the ESR and Mössbauer spectra of heat-treated specimens.
Synthesis of Stable 1,2-Diazocines, 4,7-Disubstituted 3,8-Diaryl-1,2-diazacycloocta-2,4,6,8-tetraenes, and Their Thermolysis
Authors: Yogi Seiichi , Hokama Kozo , Ueno Kazunori , Tsuge Otohiko
Published: July 2006

Stable 1,2-diazocines, 3,8-diaryl-4,6-dichloro-1,2-diazacycloocta-2,4,6,8-tetraenes, were prepared via a chlorination–dehydrochlorination sequence starting from readily-available 3,8-diaryl-1,2-diazacycloocta-2,8-dienes. When reacted with metal carboxylates in benzene under reflux, the dichloro-1,2-diazocines were converted into stable 4-acyloxy- and/or 4,7-bis(acyloxy)-1,2-diazocines. On the thermolysis in toluene under reflux, all the diazocines gave only pyridine derivatives with extrusion of the corresponding benzonitriles. The thermal behavior of the diazocines are also discussed.
Anthracene Derivatives as Acceptors of the Reaction Intermediate Generated by the Decomposition of Tropone Tosylhydrazone Sodium Salt. Regioselective Cycloaddition Reactions of Cycloheptatrienylidene or 1,2,4,6-Cycloheptatetraene with 9-Substituted Anthracene Derivatives
Authors: Saito Katsuhiro , Ishihara Hiraku
Published: July 2006

The rearrangement of the carbene, cycloheptatrienylidene, to the allene, 1,2,4,6-cycloheptatetraene, was investigated. Tropone tosylhydrazone sodium salt, the precursor of cycloheptatrienylidene was decomposed in the presence of various kinds of 9-substituted anthracene derivatives to afford cycloaddition products, whose structures show that the carbenic carbon atom or the allenic carbon atom of the carbene or the allene attacks the carbon atoms at the 10-position of the anthracenes. It is obvious that the electronic natures of the substituents on the anthracenes have no effect on the regioselectivity of the addition reaction, suggesting that the reaction proceeds via 1,2,4,6-cycloheptatetraene, which is derived from the cycloheptatrienylidene initially generated from the tosylhydrazone.
NMR Study on Inclusion Complexes of l-Phenylalanine and Aspartame with Cyclodextrins in Aqueous Solution
Authors: Takahashi Shin-ichiro , Suzuki Ei-ichiro , Nagashima Nobuya
Published: July 2006

The interactions of Phenylalanine and Aspartame (N-l-α-Aspartyl-l-phenylalaninel-methyl ester, APM) with α- and β-cyclodextrins (CD) in aqueous solutions were investigated by 1H and 15N NMR techniques. The changes in chemical shift of CD protons on going from free CD to the mixture with phenylalanine and APM indicate that the phenyl ring is included in the cavity of CD in the complex states. The changes in the chemical shift of the β-protons of phenylalanine and APM following the binding to α- and β-CD indicate that the simple association constants (Ka) are not applicable to these systems except for the case of APM/β-CD (Ka=90), and that the large changes of the rotamer fractional population of APM side-chain occur for APM/β-CD system. The analysis with Asp–Phe(15N)–OMe suggests that the torsional angles of the main chain of APM are unchanged on the formation of the inclusion complex. The low-field shifts of amide proton and its nitrogen resonances of Asp–Phe(15N)–OMe in the complex formation suggest that the amide part of APM is hydrogen-bonded to the C2 or C3 hydroxyl group of β-CD.
Voltammetric Determination of Dialkylammonium Ion in the Presence of Monoalkylammonium Ion by Addition of 18-Crown-6
Authors: Matsue Tomokazu , Akiba Uichi , Osa Tetsuo
Published: July 2006

The addition of 18-crown-6 to the electrolyte solution discriminated the reduction current peak for dialkylammonium ions from that for monoalkylammonium homologues, which made it possible to determine voltammetrically the dialkylammonium ions in the presence of the monoalkylammonium ions.
Solution Properties of Phycoerythrin. I. Characterization of Phycoerythrin
Authors: Mizuno Haruo , Iso Naomichi , Saito Takahide , Ohzeki Fumiaki , Ogawa Hiroo , Wang Zao
Published: July 2006

Phycoerythrin, one of the chromoproteins, from the red alga Porphyra yezoensis has been characterized by physicochemical measurement. The value of the sedimentation constant was 12s and it did not change with the change in pH from 5.4 to 6.8. This was assumed from the fact that the phycoerythrin did not undergo reversible dissociation-association reaction under these conditions. The weight average molecular weight of phycoerythrin was determined to be 2.2×105, and the intrinsic viscosity of phycoerythrin was determined to be 2.29×10−2 (10−1 dm3/g). From these values, the molecular shape of phycoerythrin was inferred to be globular based on the Scheraga-Mandelkern equation. The SDS-polyacrylamide gel electrophoresis of phycoerythrin showed that the phycoerythrin consisted of two subunits with molecular weights of 3.8×104 and 2.3×104. The sedimentation behavior of phycoerythrin suggested that the phycoerythrin solution was multicomponent. The phycoerythrin dissociated into two molecular species on treatment with sodium dodecyl sulfate. Their sedimentation constants were 12s and 2s. The 2s species was supposed to be phycoerythrin monomer.
The Effect of the Pressure on Proton Jumps in Ethanol–Water Mixtures at 25 °C
Authors: Ueno Masakatsu , Ito Kazunori , Tsuchihashi Noriaki , Shimizu Kiyoshi
Published: July 2006

The limiting molar conductances of hydrochloric acid in 0, 5, 10, 20, 30, and 80 mol% ethanol–water mixtures, and those of potassium chloride in 80 mol% of ethanol, were determined at 25 °C as a function of the pressure up to 2000 kgf cm−2 (1 kgf cm−2=0.9807×105 Pa) from the conductances measured in a dilute concentration range. In each solvent except for 80 mol% of ethanol, the limiting molar conductances of the proton, λ°(H+), are about four to six times larger than those of the potassium ion, λ°(K+), at all the pressures studied; in 80 mol% of ethanol, the value of λ°(H+) is very close to that of λ°(K+) at atmospheric pressure. The results suggest that the proton-jump mechanism acts in the water-rich region, but not in the ethanol-rich region. The excess proton conductances at an infinite dilution, λ°E, as estimated by [λ°E=λ°(H+)−λ°(K+)], were found to increase with an increase in the pressure. The pressure dependence of the excess proton conductances normalized to their values at 1 atm, λ°E(P)⁄λ°E(1), is most prominent in 5 mol% of ethanol; its magnitude decreases in this order; 5>0>10>>20>>30 mol% of ethanol. These results are discussed in relation to the effect of ethanol molecules on the water structure in the mixtures; a small addition of ethanol to water stabilizes the three-dimensional networks of water, while a further addition of ethanol makes it difficult to form them.
The Solvent Effects on the Optical Rotatory Properties of 1,7-Diaryl-5-hydroxy-3-heptanones and Related Compounds
Authors: Ohta Shinji
Published: July 2006

The ORD and CD curves of (S)-1,7-diphenyl-5-hydroxy-3-heptanone, (S)-1,7-bis(3,4-dimethoxyphenyl)-5-hydroxy-3-heptanone, and the related model compounds were obtained in selected solvents with different polarity. Causing the 1,7-diaryl-5-hydroxy-3-heptanones dextro-rotatory in chloroform was attributed to the formation of the intramolecular hydrogen bond between the C-3 carbonyl and C-5 hydroxyl groups, regardless of the presence of the phenyl groups. On the other hand, causing the compounds levo-rotatory in methanol was proved to necessitate simultaneously the breaking of the intramolecular hydrogen bond followed by solvation to the carbonyl and/or hydroxyl groups, as well as the presence of the phenyl groups. The ca. 30% of the solvent effect on the optical rotation was based on the change in the rotational strength associated with the n→π∗ transition of the carbonyl group as changing a solvent. The residual 70% was based on the change in the rotational strength associated with the electronic transitions at around 200 nm of the carbonyl and/or hydroxyl groups.
Synthesis of 2-(Alkyl and Aryl)thiazolo[4,5-b]quinoxaline Derivatives and Study of Their Fluorescent Properties
Authors: Phadke Ravindra Chintaman , Rangnekar Dinesh Wamanrao
Published: July 2006

Synthesis of 2-(alkyl and aryl)thiazolo[4,5-b]quinoxaline derivatives has been achieved by reacting 2, 3-dichloroquinoxaline derivatives with various thiocarboxylic acid amides. The resulting compounds have been studied for their fluorescent properties. Some of these compounds have been applied as fluorescent dyes on polyester fiber having fair dyeing properties.
Ab Initio MO Theoretical Studies on Direct Fragmentation of Organic Ions Produced by Electron-Bombardment
Authors: Ichikawa Hiroshi , Shigihara Atsushi
Published: July 2006

The possibility of bond-scission within a single vibration (direct fragmentation) in a molecular ion produced by electron-bombardment has been studied. MP2/6-31G* calculations have shown that a direct fragmentation in the ground-state ion is possible for the C–H bonds of hydrocarbons.
Synthesis and Properties of Manganese(III) Complex of Salen-Analog Containing Phenolic Pendant Group
Authors: Kanda Wakako
Published: July 2006

A manganese(III) complex, [Mn(sal-pen)], with N,N′-disalicylidene-2-methyl-4-(2-hydroxy-5-methylphenyl)-1,2-butanediaminate trianion (sal-pen3−) has been synthesized and characterized. The complex was shown to have a square-pyramidal structure with a pendant phenolate group at the apex. The electronic spectral and electrochemical properties of the complex are discussed in terms of an axial coordination of the phenolate group.
Simulation of Absorption Spectra of Polyenes Produced in PVA Film by Heating and Kinetics of Polyenes Formation
Authors: Maruyama Kazunori , Také Michio , Fujii Nobuyuki , Tanizaki Yoshié
Published: July 2006

Characteristics of absorption spectra of heated PVA film could be simulated as combinations of absorption spectra of free polyenes corresponding to the type –(CH=CH)n– (n=1–13). The change in concentrations of polyenes produced in PVA films was calculated by means of simulation. Each polyene –(CH=CH)n– was assumed to be produced by a first order reaction with rate constant kn with respect to the concentration of –(CH=CH)n−1–. kn values (n=1–13) at several temperatures were obtained. Arrhenius plots of kn from straight lines, giving activation energies 57–63 kJ mol−1 for the reaction catalyzed by H3PO4 and 94–100 kJ mol−1 for that by H2SO4. The activation entropies are negative in both cases.
Liquid Crystal Materials with Sulfur Atoms Incorporated in the Principal Structure. V. New Liquid Crystal Compounds; 2,5-Diaryl-1,3-Oxathianes
Authors: Haramoto Yuichiro , Sano Makoto , Kamogawa Hiroyoshi
Published: July 2006

2,5-Bis(p-substituted phenyl)-1,3-oxathianes (5), new liquid crystal compounds, and some corresponding 1,3-dioxanes were synthesized by the acetal formation reaction. The mesomorphic behaviors of compounds 5 were compared with those of the corresponding 1,3-dioxanes and 1,3-dithianes. Compounds 5 exhibited the lowest transition temperatures between nematic and isotropic phases. This seems to originate in the bend at the 1,3-oxathiane ring containing two heteroatoms, oxygen and sulfur, different in size. Compounds 5 also tend to exhibit supercooling states in nematic phase.
The Effect of the Substrate on the Epitaxial Growth of the Hexatriacontane Crystal
Authors: Ashida Michio , Ueda Yasukiyo , Yanagi Hisao
Published: July 2006

The epitaxial crystallization of hexatriacontane vacuum-evaporated onto a gold-covered KCl (001) surface was investigated as a function of the gold coverage. The hexatriacontane film on the KCl surface was composed of rod-like crystals taking the orientation of (110)H//(001)KCl and [001]H//[110]KCl. The film on evaporated gold film was composed of lamellar crystals taking the orientation of (001)H parallel to the substrate and a random orientation in the azimuthal direction. The hexatriacontane film evaporated on the substrate which was partly covered with gold particles was composed of both rod-like and lamellar crystals. When the coverage ratio of the gold particles was low, the lamellar crystals in the hexatriacontane film took the orientation of (001)H//(001)KCl and [110]H//[110]KCl. The numbers of lamellar crystals increased, and their orientation in the azimuth became more random, with and increase in the gold coverage.
The Unreactive Nature of N(24S) to Unsaturated Hydrocarbons
Authors: Umemoto Hironobu , Nakagawa Seiko , Tsunashima Shigeru , Sato Shin
Published: July 2006

The decay rates of ground-state atomic nitrogen in the presence of C2H4(ethene), Δ1,3-C4H6(1,3-butadiene), and C2H2(ethyne) were measured by using a pulse radiolysis-resonance absorption technique. It was found that the decay rates decrease drastically upon the addition of a small amount of I2, an efficient radical scavenger. This suggests that the decay of N(4S) in the absence of I2 is due to the reactions between the N(4S) and the free radicals. The rate constants for the reactions of N(4S)+C2H4, Δ1,3-C4H6, and C2H2 were estimated to be much less than 103 m3 mol−1 s−1. The rate constant for the N+I2→NI+I reaction was measured to be 2.4×104 m3 mol−1 s−1.
Total Synthesis of Neomethynolide
Authors: Inanaga Junji , Kawanami Yasuhiro , Yamaguchi Masaru
Published: July 2006

Neomethynolide (1), the aglycone of a twelve-membered ring macrolide, neomethymycin, was totally synthesized in its optically active form via 8,9-didehydro-1. The construction of the skeleton was carried out by condensing a stereoselectively synthesized fragment, 4-t-butyldimethylsiloxy-5-(2-methoxyethoxymethoxy)3-methyl-1-hexyne, with Prelog-Djerassi lactonic ester, and mixed anhydride method was used for the lactonization of an intermediary hydroxy acid. The full stereochemistry of 1 was established by this synthesis.