bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclic Carbonates Obtained by Reactions of Alkali Metal Carbonates with Epihalohydrins
Authors: Rokicki Gabriel , Kuran Witold 
Published: July 2006

Abstract
A study has been carried out on the reaction of alkali metal carbonates with epihalohydrins in the presence of cation complexing agents e.g. crown ethers. 3-Glycidyloxypropylene carbonate was found to be formed as the main product of the reaction of epichlorohydrin with potassium carbonate promoted by 18-crown-6. The effect of various epihalohydrins and alkali metal carbonates on the reaction course was examined. It was found that the reaction of potassium hydrogencarbonate with epichlorohydrin gives 4-hydroxymethyl-1,3-dioxolan-2-one. When the reaction of epihalohydrins with potassium carbonates was carried out in the atmosphere of carbon dioxide the products contained linear carbonate linkage apart from cyclic one. From these results, a plausible mechanism was proposed for the reaction of alkali metal carbonates with epihalohydrins in the presence of crown ethers.
A Short Synthesis of Dihydrojasmone, cis- and trans-Jasmones
Authors: Ogura Fumio , Otsubo Tetsuo , Sakamoto Tetsuo , Yamaguchi Hachiro 
Published: July 2006

Abstract
The titled jasmones were synthesized from N,N′-dimethyl-2-oxo-1,3-propanedisulfonanilide, a new three carbon building block for organic preparation.
Conformations of 3-Alkoxycarbonyl-1-tetralols and 2-Ethoxycarbonyl-4-chromanols
Authors: Hanaya Kaoru , Muramatsu Takashi , Onodera Shinji , Ikegami Yusaku , Hirota Minoru 
Published: July 2006

Abstract
The 1- or 4-hydroxyl group in cis isomers of 3-alkoxycarbonyl-1-tetralols and 2-ethoxycarbonyl-4-thiochromanols are predominantly quasi-equatorial and those of the trans isomers quasi-axial. cis-2-Ethoxycarbonyl-4-chromanol prefers the quasi-axial OH conformation.
The Crystal Structure of a New Thiosilicate of Thallium, TlInSiS4
Authors: Nakamura Yuji , Aruga Atsushi , Nakai Izumi , Nagashima Kozo 
Published: July 2006

Abstract
The crystal structure of a new synthetic compound with the composition of TlInSiS4 has been determined. The crystal is orthorhombic, and the space group is Pbnm with Z=8. The cell dimensions are a=11.74(1), b=17.038(7), and c=7.285(3) Å. The structure was solved by the Patterson method and refined to a final R-value of 0.074 for all the observed reflections. The structure is characterized by a sheet structure built up from alternating infinite(InS3)n chains and dimeric Si2S6groups. The Si2S6 groups consist of two SiS4 tetrahedra sharing an edge. The thallium atoms are situated between the sheets and are surrounded by nine sulfur atoms at distances between 3.293 and 3.957 Å.
Electron Spin Distributions and g-Value Shifts in the Novel Electron Donors with 1,3-Dithiole Rings
Authors: Terahara Atsushi , Ohya-Nishiguchi Hiroaki , Hirota Noboru , Awaji Hiroshi , Kawase Tokuzo , Yoneda Shigeo , Sugimoto Toyonari , Yoshida Zen-ichi 
Published: July 2006

Abstract
The ESR spectra of the cation radicals of TTF and its related compounds in which two 1,3-dithiole rings are connected by conjugated carbon and cumulene chains are measured. The spin distributions obtained from the hfcc due to the protons and sulfur atoms agree well with the results of the MINDO/3 calculations. The spin densities on the sulfur and central carbon atoms decreases as the central chain length increases. A linear relationship, g=2.00379+0.00108 a(S), between the g-values and the sulfur hfcc is noted and explained in terms of the Stone’s theory. The g-values of the cation radicals with cumulene chains deviate from this relation and a possible cause is suggested.
Molecular Motion and Phase Transitions in 2-Methyl-2-nitropropane as Studied by Proton Magnetic Resonance and Relaxation
Authors: Hasebe Tooru , Nakamura Nobuo , Chihara Hideaki 
Published: July 2006

Abstract
Proton spin-lattice relaxation times (T1 and T1ρ) were measured in solid and liquid phases of 2-methyl-2-nitropropane. In the lowest temperature solid phase (Phase III) a broad, asymmetric minimum in T1 as well as a large reduction in the second moment was observed due to the coupled reorientations of methyl and t-butyl groups. The analyses of the T1 and T1ρ in Phase III gave the activation parameters Ea=14.6±0.2 kJ mol−1 and τ0=(6.45±0.10)×10−14 s for the methyl reorientation and Ea=15.1±0.3 kJ mol−1 and τ0=(1.35±0.10)×10−13 s for t butyl reorientation. In Phase II, the T1 is governed by the t-butyl reorientation with the activation parameters Ea=15.3±0.1 kJ mol−1 and τ0=(5.85±0.10)×10−14 s. In the low temperature region of the highest temperature plastic phase (Phase I) the molecular overall reorientation governs the T1 and the molecular translational self-diffusion becomes the dominant relaxation mechanism near melting point. The T1ρ results were analyzed with the isotropic translational diffusion model and the activation parameters were determined to be Ea=46.5±0.9 kJ mol−1 and τ0=(4.6±1.8)×10−15 s. The mean jump time of the molecule at the melting point, 6×10−7 s, is slightly longer than those in other plastic crystals. The activation energy for the translational diffusion is 9.7±1.5 kJ mol−1 in the liquid phase.
Kinetic and Thermodynamic Characterization of Thermal Pyridine Liberation-Anation Reactions of Bis(2,3-alkanedione dioximato)dipyridinecobalt(III) Iodide in the Solid State
Authors: Kinoshita Setsuko , Wakita Hisanobu , Masuda Isao 
Published: July 2006

Abstract
Thermodynamic and kinetic characterizations were carried out on the thermal, pyridine liberation-anation reactions, [CoIII(R,CH3-dioxH)2(py)2]I \oversetΔ→ [CoIII(R,CH3-dioxH)2(py)I]+py↑.* These occurred endothermally in the solid state of the complexes. The ΔH values of the reactions were determined. A large increment in the entropy was found to be indispensable for the progress of the reactions; it could be brought about by the liberation of gaseous pyridine from the solid system of the complexes. The kinetic analyses revealed that the reaction rates were increased by the substitution of R with the longer-carbon-chain alkyl groups. The activation enthalpies and activation free energies were shown to be decreased by the above substitutions. The CoIII-pyridine bond was observed to be weakened by the electron-donating inductive effect of R to the central cobalt atom and by the steric interference of R toward axial pyridine coordination.
Kinetic Studies of Fast Equilibrium by Means of High-performance Liquid Chromatography. V. Stepwise Complex Formation of the Nickel(II) Ion with 2,2′-Bipyridine and 1,10-Phenanthroline
Authors: Moriyasu Masataka , Hashimoto Yohei 
Published: July 2006

Abstract
The stepwise complex formation of the nickel(II) ion (M2+) with 2,2′-bipyridine(bpy) and 1,10-phenanthroline(phen) (Mn−12++L\ightleftharpoonsMLn2+ with Kn=[MLn2+]/[MLn−12+][L], where n=1–3), has been investigated by means of high-performance liquid chromatography. Peaks of the labile partially ligand substituted complexes, ML2+ and ML22+, have appeared on chromatograms, along with peaks of the ML32+ and excess free ligands, on reverse phase ion-pair chromatography using sodium dodecyl sulfate in acidic media. Each labile species has been found to be eluted without any noticeable change, such as ligand addition, dissociation, or disproportionation, during chromatography. Thus, the chromatograms obtained have directly indicated the equilibrium concentrations of each species in the solutions prior to chromatography. The stepwise complex formation constants of nickel(II) with bpy or phen have been determined by means of high-performance liquid chromatography.
The Color Reaction of Purine Bases by Ternary-complex Formation with Eosin and Silver(I)
Authors: Fujita Yoshikazu , Mori Itsuo , Kitano Shoko , Kawabe Hiroshi , Kamada Yoshiyuki 
Published: July 2006

Abstract
A color reaction of purine bases utilizing a ternary-complex system among a purine base, a metal ion, and a xanthene dye was studied, and the fundamental conditions for the spectrophotometric determination of purine bases(as adenine) with eosin and silver(I) were established. The absorption maxima of the ternary-complexes lie at 550–560 nm against water. The optimum pH ranges for the color formation of the complexes are pH 4.8–5.4. Beer’s law is obeyed over the range of 1–10 μg/10 cm3 of adenine, and the apparent molar absorptivity is 1.1×105 dm3 mol−1cm−1 at 560 nm. In the determination of adenine, the coexistence of pyrimidine bases, such as uracil and cytosine, and nucleotides containing adenine, such as 5′-adenosine triphosphate(ATP) and β-nicotinamide–adenine dinucleotide(NAD), scarcely interfere.
Photooxygenation Reactions of 4-Flavanols and Benzylic-type Alcohols
Authors: Suzuki Morio , Yamazaki Eiji , Takabe Fumiaki , Morioka Motonobu , Mizuno Hideo , Matsushima Ryoka 
Published: July 2006

Abstract
On irradiation in benzene under oxygen atmosphere cis- and trans-4-flavanols gave flavanones with significant structural effects on the yield: A high cis/trans selectivity and enhancement effect by electron-donating substituents. A series of benzylic-type alcohols showed similar substituent effects. The structure-reactivity relationships were explained in terms of the stereoelectronic requirements for favorable overlapping of intermediates. In order to infer the active oxidant species, the above photoreactions were compared with the oxidations by singlet oxygen and superoxide ion. The involvement of superoxide ion or its related species such as electron transfer complex R+····O2−· was suggested. The effects of additives and solvents were also investigated.
Atmosphere Dependent Photoreaction of 4-Pyridinecarboxylic Ester in Acidic Methanolic Solutions
Authors: Sugiyama Toru , Kusano Yukari , Yagi Kazuya , Ito Yoko , Sugimori Akira 
Published: July 2006

Abstract
The UV-irradiation of methyl 4-pyridinecarboxylate (1) in methanol under oxygen in the presence of sulfuric acid brings about methoxylation at the 3-position of the pyridine ring, while under nitrogen methoxylation and hydroxymethylation occur at the 2-position. The change of photoreactions of 1 caused by oxygen can not be explained either by the promotion of intersystem crossing by O2 or by the charge transfer interactions between 1 and O2.
Differential Scanning Calorimetric Studies on the Thermal Denaturation of Ribonuclease A in Aqueous 2-Methyl-2,4-pentanediol
Authors: Fujita Yukihisa , Noda Yukinao 
Published: July 2006

Abstract
The thermal denaturation of ribonuclease A in aqueous solutions of 2-methyl-2,4-pentanediol(MPD) was investigated by differential scanning calorimetry at pH 5.8, i.e., conditions similar to those used to crystallize the protein, and also at pH 3. A two-state reversible denaturation occurred in aqueous MPD up to 50%(v/v) MPD. Under both conditions the denaturation temperature, Td, decreased almost linearly with increasing MPD concentration; there was a slightly greater effect at pH 5.8. The calorimetric enthalpy, ΔHd, first increased with increasing MPD concentration and then decreased slightly at MPD concentrations above 20–30%. This behavior is analogous to that observed for organic additives, such as ethanol and dimethyl sulfoxide, with denaturing agents. The plot of ΔHd against ΔSd, the denaturation entropy at Td, gave a linear correlation between these parameters, indicating a close relationship between the MPD-induced unstabilization of the protein and the water structure around the protein molecule. The standard thermodynamic parameters for denaturation, ΔG°, ΔH°, and ΔS°, were calculated from Td and ΔHd, assuming a constant heat capacity change. The unstabilizing effect of MPD on the thermal stability of the protein results from that the increase in ΔH°, induced by MPD, is compensated by a large increase in ΔS°, with a resulting decrease in ΔG°; it is in accord with an effect on solvent ordering around the exposed nonpolar groups of the protein. It also indicates a temperature dependence of the MPD effect on the protein stability.
1-Bromo-2-ethoxycyclopropyllithium: A Synthetic Equivalent of 2-Lithio-or 3-Lithiopropenal. Application to the Synthesis of Juvenile Hormone (JH-II), β-Sinensal, and Jasmonoids
Authors: Morizawa Yoshitomi , Kanakura Akihiro , Yamamoto Hajime , Hiyama Tamejiro , Nozaki Hitosi 
Published: July 2006

Abstract
The ethyl vinyl ether-dibromocarbene adduct was lithiated with butyllithium at −95 °C in tetrahydrofuran. The resulting lithium carbenoid 3 was allowed to react with various electrophiles to give 1-substituted trans-1-bromo-2-ethoxycyclopropanes (1) in good yields. The trans relationship of Br and OEt groups was found particularly pertinent to the ethanolysis of 1 producing 2-substituted propenal diethyl acetal derivatives. The reaction has been applied to 1-methoxycyclohexene–dibromocarbene adducts, giving rise hereby 2-substituted 2-cyclohepten-1-one dimethyl acetals under ring enlargement. The transformation has been utilized in the synthesis of a homoterpenoid (JH-II) or a terpenoid (β-sinensal) structure by SN2′ substitution of allylic acetates with lithium dimethylcuprate(I) or iron pentacarbonyl respectively. The reaction products of 3 with aldehydes are oxidized with dimethyl sulfoxide to give cyclopropyl ketones whose ethanolysis in the presence of boron trifluoride ether complex gives β-bromo γ-keto aldehyde acetals. Debromination followed by acidic hydrolysis produces γ-keto aldehydes serving as precursors of dihydrojasmone and cis-jasmone.
Mechanism of the Reactions of Oxomolybdenum(V) Tetraphenylporphyrin Complex with Alcohols in the Presence of Superoxide
Authors: Imamura Taira , Hasegawa Koichi , Tanaka Tetsuya , Nakajima Wataru , Fujimoto Masatoshi 
Published: July 2006

Abstract
The successive addition of ROH (R=CH3 and C2H5) to the dichloromethane solution of MovO(tpp)Br (tpp=meso-tetraphenylporphinato) causes two-step reactions at 25 °C. The products of the first and the second step of the reactions are alcohol complex, [MovO(tpp)(ROH)]Br, and alkoxo complex, MovO(tpp)OR, respectively. In the presence of superoxide ion, O2−, in the dichloromethane solution of MovO(tpp)X (X=Br and NCS) containing alcohol, MovO(tpp)OR is formed through competitive two reaction paths where O2− acts as a proton acceptor and a reducing agent. The reaction steps of the two paths were confirmed by optical and ESR studies.
Practical Procedure for the Chemoselective Reduction of Esters by Sodium Borohydride. Effect of the Slow Addition of Methanol
Authors: Soai Kenso , Oyamada Hidekazu , Takase Masako , Ookawa Atushiro 
Published: July 2006

Abstract
The effect of solvents on the reduction of esters was examined with readily available sodium borohydride which is known to be incapable of reducing such functional groups. In mixed solvents of t-butyl alcohol–methanol or tetrahydrofuran–methanol, various carboxylic esters and lactones were found to be reduced by sodium borohydride to the corresponding alcohols or diols in high yields. Slow addition of methanol to the refluxing mixture of ester and sodium borohydride in t-butyl alcohol or tetrahydrofuran was essential to achieve effective reduction. On the other hand, each individual solvent, methanol or t-butyl alcohol, was not effective for the reduction. The procedure provided a practical method for the functional group selective reduction of esters in the presence of chloro, cyano, carboxylato, carbamoyl, carboxy or nitro groups, which can not usually be performed by lithium aluminium hydride.
Syntheses of the Sex-Attractant of Pine Sawflies
Authors: Kikukawa Tadashi , Imaida Motomasa , Tai Akira 
Published: July 2006

Abstract
In order to establish the stereochemistry of the sex attractant of various species of pine sawflies, (2S,3R,7R)-, (2S,3R,7S)- and (2S,3S,7S)-2-acetoxy- and 2-propionyloxy-3,7-dimethylpentadecane were synthesized. The alcohol moiety of each pheromone was prepared by the coupling of Grignard reagent of C12 block with tosylate of C5 block. The C12 blocks, (R)- and (S)-1-bromo-2-methylundecane, were prepared from (R)-(+)-pulegone. The C5 blocks, (2R,3S)- or (2S,3S)-2-methyl-3-tetrahydropyranyloxy-1-(tosyloxy)butane, were derived from (2S,3S)- or (2R,3S)-2-methyl-3-hydroxybutyric acid prepared by the enantio-differentiating hydrogenation of methyl 2-methyl-3-oxobutyrate over the asymmetrically modified nickle catalyst.
Liquid Crystal Materials with Sulfur Atoms Incorporated in the Principal Structure 1. New Liquid Crystal Compounds with 1,3-Dithiane Ring
Authors: Haramoto Yuichiro , Nobe Atushi , Kamogawa Hiroyoshi 
Published: July 2006

Abstract
2-(p-Substituted phenyl)-5-alkyl-1,3-dithianes, new liquid crystals, were synthesized by the thioacetalization of the corresponding aldehydes and dithiols. These compounds have characteristic supercooling states, exhibit monotropic liquid crystal phases even in the case of long terminal alkyl substituents. The mesomorphic characteristics of these compounds were different from those of the corresponding 1,3-dioxanes, this must originate in the difference in the molecular width caused by the difference in the atomic volume between sulfur and oxygen.
Reaction of N-Aroyl-N-t-butylhydroxylamines with Thionyl Chloride. Synthesis of Substituted Benzohydroximoyl Chlorides
Authors: Uchida Yuzuru , Kozuka Seizi 
Published: July 2006

Abstract
The reaction of N-benzoyl-N-t-butylhydroxylamine with thionyl chloride in carbon tetrachloride gave O-chlorosulfinylbenzohydroximoyl chloride as the main product. On treating with ethanol, the compound gave benzohydroximoyl chloride in good yield. The reaction was applied to the synthesis of substituted benzohydroximoyl chlorides.
Selective Formation of Solute Radicals in the Radiolysis of Neopentane-Cyclopentane Mixtures at 4 and 77 K as Studied by Capillary Gas Chromatography and ESR Spectroscopy
Authors: Tilquin Bernard , Gourdin-Serveniere Catherine , Miyazaki Tetsuo , Fueki Kenji 
Published: July 2006

Abstract
The dimer yields in the radiolysis of the neo-C5H12-cyclo-C5H10 (1 mol%) mixtures at 77 and 4 K have been measured by capillary gas chromatography. Analysis of the results indicates that cyclopentyl radicals are produced selectively at 77 K, while their selective formation is suppressed at 4 K. This result coincides well with the data obtained by ESR spectroscopy.
Disproportionation reaction of Nitrogen Monoxide on CaHY-type Zeolite
Authors: Kanno Yoshinori , Imai Hisao 
Published: July 2006

Abstract
The disproportionation reaction of NO was investigated on CaHY-type zeolite. The relation between pretreatment temperature and activity was determined by the pulse reaction technique, and the dependence of the initial formation rate of N2O on NO pressure was investigated with a gas circulation system. The rate of initial formation of N2O is third order in NO pressure in the lower pressure region (ca. 30 Torr, 1 Torr≈133.322 Pa) and 2.2th order in NO pressure in the higher pressure region (ca. 200 Torr). TPD spectra are composed mainly of three peaks: The first peak is assigned to the unreactive adsorbed NO, the second to the NO produced by the decomposition of N2O3 and left on the zeolite surface, and the third to the N2O remaining. On the basis of the reaction mechanism proposed by Chao and Lunsford, the rate equation for the initial formation of N2O has been derived as α=\bark2K1P3⁄(1+K1P2) where P, K1 and \bark2 are the pressure of NO, an equilibrium constant, and a rate constant, respectively. This equation is in good agreement with experimental results obtained with the gas circulation system.
Adsorptions of Organic Compounds in Basic Solutions
Authors: Urano Kohei , Kano Hisanao 
Published: July 2006

Abstract
The adsorption isotherms of various aromatic compounds on an activated carbon or a polystyrene adsorbent in aqueous solutions and basic solutions were investigated. The adsorption isotherms of nonionic compounds and strong anionic electrolytes in the basic solutions were equal to the isotherms in the aqueous solutions. However, the adsorbed amounts of weak anionic electrolytes decreased with ionization in the basic solutions, and the adsorption isotherms of the non-ionized form and the ionized form of all these compounds except phenol could be expressed by the Freundlich equations with the same values of n. The amounts of those weak anionic electrolytes adsorbed at a desired pH could be calculated from the adsorption isotherms of the non-ionized form and the ionized form and the ionization constants.
Bromochlorination of Alkenes with Dichlorobromate(1–) Ion. I
Authors: Negoro Takeshi , Ikeda Yoshitsugu 
Published: July 2006

Abstract
In the reaction of styrene with chlorine, the added bromide ions were mostly incorporated into the adduct, giving a bromo chloro compound. Tetrabutylammonium dichlorobromate(1–) was found to be an efficient bromochlorinating agent. The reactions of 2-butenes and stilbenes were completely anti stereospecific.
Photoinduced Addition Reaction of 1,4-Dibromo-2,5-piperazinedione with 1-Alkenes
Authors: Itoh Kuniaki , Yamada Hiroshi , Sera Akira 
Published: July 2006

Abstract
Irradiation of 1,4-dibromo-2,5-piperazinedione (1) with olefins in acetonitrile gave mixtures of addition products (1:1-adducts and 1:2-adducts). Addition of 1,2-epoxybutane (a hydrogen bromide scavenger) resulted in enhanced yields of the adducts. Structures of the adducts were elucidated and a reaction mechanism is discussed.
Phosphinyl- and Phosphinothioylamino Acids and Peptides. VIII. New Practical Removal Conditions for the S-Mpt Group and their Application for the Synthesis of Bis[N,N-diallyl-[d-Ala2, l-Leu5]-enkephalyl]cystine
Authors: Ueki Masaaki , Shinozaki Kozo 
Published: July 2006

Abstract
Synthesis of bis[N,N-diallyl-[d-Ala2, l-Leu5]-enkephalyl]cystine, which is expected to be a selective opioid δ-receptor antagonist, was studied. The mercapto group of cysteine was protected by the dimethylphosphinothioyl(Mpt) group. For the removal of this group without damaging the allyl moiety, new mild removal conditions by use of KF/18-crown-6 in a solvent mixture of acetonitrile–methanol are proposed. Bis[d-Ala2, l-Leu5]-enkephalyl]cystine was also prepared in a similar manner.
The Effect of Ethylene Glycol on the Thermal Denaturation of Ribonuclease A and Chymotrypsinogen A as Measured by Differential Scanning Calorimetry
Authors: Fujita Yukihisa , Noda Yukinao 
Published: July 2006

Abstract
The thermal denaturation of ribonuclease A(RNase A) and chymotrypsinogen A in aqueous solutions of ethylene glycol (EG) was investigated by differential scanning calorimetry at several pH values in the acidic region. The calorimetric enthalpies of denaturation, ΔHd, of these proteins increased monotonously with increasing the EG concentration under all the conditions studied. These proteins, however, differed from one another in the variation of the denaturation temperature, Td, with the addition of EG. The Td of chemotrypsinogen decreased slightly with an increase in EG concentration under all the conditions, producing a greater effect at high pH. The Td of RNase A, on the other hand, was almost independent of the EG content at pH 3.8, while at pH 2 and 3, the Td increased slightly with increasing the EG concentration and decreased slightly at pH 5. That is, EG stabilized or unstabilized these proteins against thermal denaturation, in a way which seemed to be dependent on temperature rather than the pH. The standard thermodynamic parameters for denaturation, ΔG°, ΔH°, and ΔS°, which were calculated using Td and ΔH° and assuming a constant heat capacity change, suggested that the slight increase or decrease in ΔG° induced by EG is attributed to whether ΔH° increases as much as ΔS° does or not. These results may be explained on the basis of the effect of EG on the solvation around hydrophobic groups of the protein. The EG effect may depends on the structural properties of proteins such as hydrophobicity and polarity, as well as on temperature.