bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prediction of Adsorbability of Organic Compounds from Aqueous Solution on Activated Carbon by Means of the Linear Free-energy Relationship
Authors: Abe Ikuo , Hayashi Katsumi , Kitagawa Mutsuo , Hirashima Tsuneaki 
Published: July 2006

Abstract
A method is presented for predicting the adsorbability of a wide variety of organic compounds from aqueous solution onto an activated carbon. The method, which is based on the linear free-energy relationship, requires only the solute’s molecular refraction and the number of hydrophilic functional groups. The molecular refraction represents the free energy contribution by the solute-adsorbent interaction and the number of hydrophilic functional groups represents that by the solute-solvent interaction.
Cyclopropanation of Electron-deficient Olefins with Dibromomethane by Ni(0) Complexes and Zinc
Authors: Kanai Hiroyoshi , Hiraki Nobuyuki , Iida Shigeki 
Published: July 2006

Abstract
A new method for the synthesis of cyclopropane derivatives is described. It involves treatment of electrondeficient olefins with dibromomethane in the presence of Ni(0) complex/zinc/Lewis acid (or alkali halide) systems. Ni(PPh3)4/Zn/ZnBr2 system was effective for the cyclopropanation of methyl acrylate and acrylonitrile, but was ineffective for that of methyl vinyl ketone and acrylaldehyde. Ni(COD)2/Zn/NaI system was applicable to the cyclopropanation of methyl vinyl ketone as well as to that of methyl acrylate and acrylonitrile. Alternative catalytic systems which were easy to handle were exploited, involving in situ generated Ni(0) complexes prepared from NiBr2(PPh3)2 and zinc, or nickel bromide, sodium iodide, zinc, and an olefin. Catalytic amounts of nickel compounds are sufficient for the cyclopropanation of methyl acrylate, acrylonitrile, and methyl vinyl ketone, but a 1 : 2 nickel : acrylaldehyde mole ratio results in the best yield. A mechanism is proposed which involves metallacyclobutane as an intermediate.
Metalloenzyme Models. Divalent Metal Ion Catalyzed Hydrolysis of p-Nitrophenyl Picolinate in the Presence of Imidazoles and Pyridines Having Hydroxyl Groups in Their Side Chains
Authors: Ogino Kenji , Shindo Katsuhiko , Minami Tooru , Tagaki Waichiro , Eiki Toshio 
Published: July 2006

Abstract
Rate constants for hydrolysis of p-nitrophenyl picolinate at 25 °C in the pH range 6.5–8.5 were measured in the absence and presence of divalent metal ions (Ni(II), Zn(II), Co(II), Ca, Mg) and substituted imidazoles or pyridines as ligands having alcoholic hydroxyl groups in their side chains. In the presence of either metal ion or ligand, the rate is slow and the pseudo-first-order rate constant (kobsd) increases linearly in a first-order manner with respect to the concentration of metal ion or ligand until it gives the second-order rate constant, kM or kL, respectively. In the presence of both a metal ion (Ni(II) or Zn(II)) and a ligand, rate increase is remarkable for some ligands and the increase in kobsd values constructs saturation curves with respect to increase in either metal ion or ligand concentration. The saturation curves were analyzed based upon rate equations formulated by assuming the formation of 1 : 1 complex of metal ion and ligands as the catalyst, leading to evaluation of the association constant K for complexes and the second-order rate constant kc for the reaction of complex with substrate. Values of kobsd, kc, and K are dependent greatly upon the structure of ligands and pH. The ligands complexed with Zn(II) ion appear to be simple but highly active models of hydrolytic metalloenzymes.
Mechanism for the Oxidative Cleavage of Electron-deficient Acetylenes with Alkaline Hydrogen Peroxide
Authors: Sawaki Yasuhiko , Inoue Hiroshi , Ogata Yoshiro 
Published: July 2006

Abstract
4-Phenyl-3-butyn-2-one (1a) was effectively cleaved by alkaline hydrogen peroxide to afford benzoic and acetic acids. The rate ratio for the addition of HOO− and HO− to 1a resulted in kHOO−/kHO−=1400, which is comparable to that of benzylideneacetone. The major reaction of the cleavage proceeds via benzoylacetone. As a minor pathway, α-keto oxirene intermediate is formed and rearranges only to α-benzoylpropionate in a different way from the corresponding diketo carbene. α-Keto esters are found to be converted by HOO− to α-alkoxy ketones via a novel oxidative substitution of ester group. Methyl phenylpropiolate is oxidized by HOO− similarly as 1a. The mechanism is discussed on the basis of oxirene intermediate inconvertible to keto carbene.
Solution Conformation of Cyclic Dipeptides Having Aliphatic Side Chains
Authors: Tanihara Masao , Hiza Tae , Imanishi Yukio , Higashimura Toshinobu 
Published: July 2006

Abstract
Cyclic dipeptides having aliphatic side chains, cyclo(l-Val)2, cyclo(l-Val–d-Val), cyclo(l-Leu)2, and cyclo(l-Leu–d-Leu) were synthesized and their conformation in solution was investigated by circular dichroism (CD) and proton nuclear magnetic resonance (1H NMR) spectroscopy. 1H NMR spectra in (CD3)2SO of cyclo(l-Val–d-Val) and cyclo(l-Leu–d-Leu) indicated that the diketopiperazine ring of these trans cyclic dipeptides takes a planar or a chair conformation and the molecules take a center-symmetric conformation. 1H NMR spectra in (CD3)2SO and CD spectra in CH3OH and H2O of cyclo(l-Val)2 and cyclo(l-Leu)2 indicated that the conformation of these cis cyclic dipeptides is planar-axial and flagpole-boat-type respectively. It is suggested that cis cyclic dipeptides having aliphatic side chains take such conformations in polar solvents because of the stabilization by attractive forces between aliphatic side chains.
Solution Conformation of cyclo(–l-Cys(S-Acm)–d-Leu–l-His–l-Cys(S-Acm)–d-Leu–l-His–) and Interaction with Cu(II)
Authors: Kodaka Masato , Shimizu Toru , Hatano Masahiro 
Published: July 2006

Abstract
Proton NMR spectra of a cyclic peptide, cyclo-(S-acetarnidoinethyl-l-cysteinyl)-d-leucyl-l-histidyl-(S-acetamidomethyl-l-cysteinyl)-d-leucyl-l-histidyl, were measured and analyzed in order to investigate its conformation and its interaction with Cu(II). A linear peptide, [N-(t-butoxycarbonyl)-S-acetamidomethyl-l-cysteinyl]-d-leucyl-l-histidyl-(S-acetamidomethyl-l-cysteinyl)-d-leucyl-l-histidine methyl ester, was also investigated for comparison. It was strongly suggested that the cyclic hexapeptide forms transannular hydrogen bonds between the cysteine residue peptide bonds and thus two β-turns exist in the d-leucyl-l-histidyl sequences. This finding is particularly noteworthy because the present cyclic peptide has no prolines which are frequently seen in β-turn structures of proteins, naturally occurring peptides or synthetic peptides and because the cyclic peptide we studied is composed of amino acids all bearing the large side chains which seemed likely to prevent β-turn formation due to their steric hindrance. The interactions of the cyclic peptide and the linear peptide with Cu(II) were also studied by observing 1H NMR spectral changes on addition of CuCl2. It was suggested that the imidazolyl groups in the peptides are directly coordinated to Cu(II).
Phosphinyl and Phosphinothioyl Amino Acids and Peptides. VII. The Use of the Dimethylphosphinothioyl Group as a Thiol-protecting Group of Cysteine
Authors: Ueki Masaaki , Shinozaki Kozo 
Published: July 2006

Abstract
The use of the dimethylphosphinothioyl (Mpt) group for the protection of the thiol function in the cysteine side-chain was studied. N,S-Bis(Mpt)-l-cysteine was obtained directly by means of a Schotten-Baumann-type reaction of Mpt–Cl with l-cysteine. The S–Mpt group was stable under acidic conditions, except for HBr in acetic acid, and it could be removed by treatment with AgNO3 or Hg(OAc)2 in an aqueous medium. Glutathione was synthesized by utilizing the new S-protecting group.
Bromination of Biphenylene Derivatives Having an Electron-releasing Substituent. A Preferential Formation of Benzocyclooctene Derivatives
Authors: Kidokoro Hiroto , Saito Yuko , Sato Masaru , Ebine Seiji , Sato Sadao , Hata Tadashi , Tamura Chihiro 
Published: July 2006

Abstract
3-Substituted 2-bromobiphenylenes were brominated to give benzocyclooctene or 7(8H)-benzocyclooctenone derivatives, but not biphenyl derivatives. The structure of 5,8,10-tribromo-7(8H)-benzocyclooctenone was determined by X-ray diffraction analysis.
Effect of Lattice Anions on the Racemization of Optically Active Metal Chelate Salts in the Solid State. 2. [Co(phen)3]X3, [Co(phen)2(en)]X3, and [Co(phen)(en)2]X3, Where X−=Cl−, Br−, or I−
Authors: Fujiwara Terufumi 
Published: July 2006

Abstract
The kinetics of racemization of the anhydrous complexes (−)-[Co(phen)3]X3, (+)-[Co(phen)2(en)]X3, and (−)-[Co(phen)(en)2]X3, where phen=1,10-phenanthroline, en=ethylenediamine, and X−=Cl−, Br−, or I−, have been examined in the solid state. A rapid initial loss of optical activity and a subsequent first-order racemization were observed for the complex salts. Enthalpies and entropies of activation, ΔH\eweq and ΔS\eweq, were evaluated for the first-order process of [Co(phen)3]X3 and [Co(phen)2(en)]X3. It was found that for [Co(phen)3]X3 the chloride salt racemizes more rapidly than the bromide salt and that ΔH\eweq and ΔS\eweq, decrease with the lattice anion in the order X−=Br−&gt;Cl−. On the other hand, the reverse sequence in ΔH\eweq and ΔS\eweq, X−=Br−&lt;Cl−, was observed for [Co(phen)2(en)]X3. Moreover, the rate of racemization of [Co(phen)(en)2]X3 was found to decrease with the lattice anion in the order X−=I−&gt;Br−&gt;Cl−. These anion effects for the series were successfully interpreted in terms of the chemical interactions due to donicity and hydrogen bonding ability of anions, but not in terms of the physical factor, lattice energy. Thermal decomposition studies of the complexes lend support to the interpretation of the racemization kinetic data.
Studies on Salt Hydrate for Latent Heat Storage, II. Eutectic Mixture of Pseudo-binary System CH3CO2Na·3H2O–CO(NH2)2
Authors: Wada Takahiro , Kimura Fumiko , Yamamoto Ryoichi 
Published: July 2006

Abstract
With a view of developing latent heat storage materials, mixtures of pseudo-binary system, CH3CO2Na·3H2O–CO(NH2)2 (sodium acetate trihydrate–urea) were subjected to differentital scanning calorimetry, and the partial phase diagram for ternary system CH3CO2Na–CO(NH2)2–H2O at ambient pressure was constructed. The eutectic mixture, containing 0.6 mass fraction of CH3CO2Na·3H2O and 0.4 mass fraction of CO(NH2)2, melts congruently at 31.5 °C with a heat of fusion of 226 J/g, which is larger than the heat of fusion of CaCl2·6H2O, 180 J⁄g. Thus, mixtures of system CH3CO2Na·3H2O–CO(NH2)2 are promising for solar energy storage.
Synthesis of the 1,2,4-Triazolo[4,3-a]quinazolin-5-ones and Related Compounds
Authors: El-Sherief H A , Abdel-Rahman A E , El-Naggar G M , Mahmoud A M 
Published: July 2006

Abstract
2-Hydrazino-3-phenyl-4(3H)-quinazolinone (1) underwent ring closure with aliphatic acid, aldehydes, and carbon disulfide to 1-alkyl-, 1-aryl-, and 1-mercapto-4-phenyl-1,2,4-triazolo[4,3-a]quinazolin-5(4H)-ones (7) for instance. The 1-alkylthio-3-phenyl-1,2,4-triazolo[4,3-a]quinazolin-5(4H)-ones were readily obtained from 7 and alkyl halides. Reaction of 1 with ethyl acetoacetate gave the corresponding hydrazone which was readily converted into 2-(3-methyl-5-oxo-2-pyrazolin-1-yl)-3-phenyl-4(3H)-quinazolinone.
Growth Morphology of Alumina Whiskers
Authors: Hayashi Takashi , Iwata Masatoshi , Saito Hajime 
Published: July 2006

Abstract
Alumina whiskers were grown on a substrate by hydrolysis of aluminium fluoride vapor. The present paper describes some observations concerning the growth and morphology of alumina whiskers. The most frequently observed types in this work were A2-whiskers and C-whiskers.
Reaction Mechanism of 2-(Trimethylsilylmethyl)pyridine with Benzonitrile
Authors: Konakahara Takeo , Sato Kenji 
Published: July 2006

Abstract
The mechanism of the reaction of lithiated 2-(trimethylsilylmethyl)pyridine with benzonitrile is discussed. The reaction proceeds through (E)- and (Z)-1-phenyl-2-(2-pyridyl)-1-(trimethylsilylamino)ethene, which are quantitatively converted to 2-phenacylpyridine by acidic hydrolysis.
Tosylation Reaction of d-Glucuronolactone
Authors: Itoh Hiroshi , Tajima Kiyohiko 
Published: July 2006

Abstract
The tosylation reaction of d-glucuronolactone with tosyl chloride in pyridine gave directly 5-O-tosyl-d-glucuronolactone and 2,5-di-O-tosyl-d-glucuronolactone.
An Improved Method for Preparation of N-Alkyl-2(3H)-benzothiazolone Analogs
Authors: Tanabe Yoo , Okabe Takayuki , Kakimizu Akiko , Ohno Nobuo , Yoshioka Hirosuke 
Published: July 2006

Abstract
A number of N-alkyl-2(3H)-benzothiazolone analogs could be prepared from N-monosubstituted aniline and chlorocarbonylsulfenyl chloride. The new method consists of carbamoylation of aniline and successive Friedel-Crafts type ring closure of an intermediate carbamoylsulfenyl chloride in the presence of suitable Lewis or protic acid catalyst.
The Generation of the Ethenethiolate Anion and Its Reaction with Several Chloromethyl Alkyl Ethers and Sulfides
Authors: Tanimoto Shigeo , Ikehira Hideyuki , Oida Tatsuo , Kokubo Toshio 
Published: July 2006

Abstract
2-Ethoxy-1,3-oxathiolane was deprotonated at the 4-position, followed by the cycloelimination of the resultant anion, leading to ethyl formate and the ethenethiolate anion. The anion was trapped by several chloromethyl alkyl ethers and sulfides to afford alkoxy(vinylthio)methanes and alkylthio(vinylthio)methanes respectively.
A Revised Absolute Configuration of 2-Hydroxy-1,1′-binaphthyl
Authors: Kabuto Kuninobu , Yasuhara Fujiko , Yamaguchi Shozo 
Published: July 2006

Abstract
The absolute configuration of 2-hydroxy-1,1′-binaphthyl (3) has been revised to (R)-(+) in THF by a reexamination of the previously reported chemical correlation between 3 and 2,2′-diamino-1,1′-binaphthyl. This revised configuration agreed with that obtained from the assignment by means of the MTPA/LSR method.
Concentration of Organic Pollutants in Water by Evaporation at Reduced Pressure
Authors: Urano Kohei , Yap Seok Ching , Hayashi Koji 
Published: July 2006

Abstract
The relative volatilities α of various organic compounds were obtained as a parameter to determine the recovery for the concentration at reduced pressure and room temperature. The evaporation technique is an efficient method for concentrating large molecular weight compounds and ionizing compounds, if ionization is promoted by adjusting the pH of water.
Catalytic Activity of Sn–Mo Oxides for Propene Oxidation
Authors: Ono Takehiko , Ikehata Tetsuo , Kubokawa Yutaka 
Published: July 2006

Abstract
Sn–Mo oxides were subjected to experimental studies with reference to their catalytic C3H6 oxidation and their own reduction by C3H6. In the oxidation Sn–Mo oxides are 30–40 times more active than MoO3 but only 4–5 times than SnO2. With Sn–Mo oxides as well as SnO2, the oxidation is zero order in C3H6 and about half order in O2, in contrast to those with MoO3. It is proposed that the oxidation proceeds via a redox mechanism with the reduction step proceeding very rapidly. 18O tracer experiments show that the mobility of lattice oxygen in Sn–Mo oxides is lower than that in MoO3 but similar to that in SnO2. From these results together with those of structural studies, it is concluded that the active phase of Sn–Mo oxides is characterized by the MoO3 highly dispersed on SnO2 or Mo ions dissolved in SnO2, and that their high reducibility possibly originates from the existence of SnO2 itself in them.
Polarizability and Electrocapillary Measurements of the Nitrobenzene–Water Interface
Authors: Kakiuchi Takashi , Senda Mitsugi 
Published: July 2006

Abstract
Electrocapillary curves have been measured of the interface between nitrobenzene solution of tetrabutylammonium tetraphenylborate and aqueous solution of lithium chloride using a dropping electrolyte solution electrode under the precise control of the electrical potential difference and of the ion transfer current across the interface. The nitrobenzene–water interface could be electrically polarized over the voltage span of 300 mV. The residual current was explained as due to both the transfer of tetrabutylammonium ion and tetraphenylborate ion through the interface and the charging current at the interface. The electrocapillary curve was parabolic in shape. The surface charge vs. potential curve derived from the electrocapillary curve agreed with that obtained from the differential capacity vs. potential curve of the interface. The results indicate that the interface can virtually be treated as an ideal polarized interface over a certain potential range.
Polarized Raman and Infrared Spectra of Tetramethyl- and 2,6-Dimethylpyrazines
Authors: Ishibashi Yoshimi , Arakawa Fumiko , Shimada Hiroko , Shimada Ryoichi 
Published: July 2006

Abstract
The polarized Raman and infrared spectra of tetramethyl- and 2,6-dimethylpyrazines were studied. Relative intensities of the non-totally symmetric Raman bands for the tetramethylpyrazine crystal were calculated assuming the oriented gas model. Assignments of the fundamental vibrations for tetramethyl- and 2,6-dimethylpyrazines were made through the expected and observed polarization behaviors of the Raman and infrared bands and also through the normal coordinate calculation.
Pressure Effects on the Hydrolysis of 3-Nitro-4-acyloxybenzoic Acids Catalyzed by Hexadecyltrimethylammonium Bromide Micelle
Authors: Makimoto Syoichi , Suzuki Keizo , Taniguchi Yoshihiro 
Published: July 2006

Abstract
The rates of the hydrolysis of 3-nitro-4-acetoxybenzoic acid (NABA), 3-nitro-4-propionyloxybenzoic acid (NPBA), 3-nitro-4-butyryloxybenzoic acid (NBBA), and 3-nitro-4-valeryloxybenzoic acid (NVBA), catalyzed by the hexadecyltrimethylammonium bromide (HTAB) micelle, were measured at pressures up to 2 kbar at 25 °C in Tris buffer solution (0.01 M, pH 8.7). The ester binding constant K increased and the rate constant of the hydrolysis catalyzed by micelle km decreased with longer alkyl chains of esters at 1 bar. The km values were separated into the contribution of kOH (hydroxide ion catalyzed hydrolysis) and kT (Tris catalyzed hydrolysis), which increased monotonically up to 2 kbar. On the other hand, the K values decreased and then inversed with minima at about 1.5 kbar except for that of NABA. From the pressure dependence of log K, the volume changes, ΔV, accompanying the ester binding to the HTAB micelle at 1 bar were estimated to be in the range of 11±2 cm3/mol for NABA to 23±2 cm3/mol for NVBA. The activation volumes for the hydrolysis catalyzed by micelle, were measured as −6±2 cm3/mol for ΔV*OH and −16±2 cm3/mol for ΔV*T for each ester. The activation volumes for the spontaneous hydrolysis were measured as −5±2 cm3/mol for ΔV*OH and −16±2 cm3/mol for ΔV*T for each ester. The reaction mechanism was discussed in terms of ΔV and ΔV*.
Synthesis of 5″-Deoxy-5″-fluorolividomycin B
Authors: Torii Takahiro , Tsuchiya Tsutomu , Umezawa Sumio , Umezawa Hamao 
Published: July 2006

Abstract
A masked lividomycin B derivative in which only the C-5″ hydroxyl group remains free has been prepared and treated with diethylaminosulfur trifluoride as the key step to give the title compound. A macrocyclic compound, that is, 2′,5″-carbamate was also obtained by the above reaction, and the structure was determined chemically and by the NMR-spectrum of its deblocked derivative.
A New Glycoside, Kusaginin Isolated from Clerodendron trichotomum
Authors: Sakurai Atsushi , Kato Takahiko 
Published: July 2006

Abstract
A new glycoside, kusaginin was isolated from Clerodendron trichotomum Thunb. and 2-(3,4-dihydroxyphenyl)ethyl 3-O-α-l-rhamnopyranosyl-4-O-(3,4-dihydroxycinnamoyl)-β-d-glucopyranoside was assigned to this substance from studies on the hydrolysis products and from analyses of the 1H NMR and 13C NMR spectra.
Studies on Aqueous Solutions of Saccharides. I. Activity Coefficients of Monosaccharides in Aqueous Solutions at 25 °C
Authors: Miyajima Koichiro , Sawada Masahiro , Nakagaki Masayuki 
Published: July 2006

Abstract
Activity coefficients of isomeric monosaccharides, d-glucose, d-mannose, and d-galactose were determined by isopiestic comparison method at 25 °C. Excess partial molar entropy of water (\barSwex) of each monosaccharide solution was negative and the absolute value increased with concentration of solute. From the magnitudes of negative \barSwex, it was concluded that the structure making ability among three isomers lies in the order d-glucose&gt;d-mannose&gt;d-galactose.
Synthesis and Epoxidation of trans-5,6-Diacetoxy-1-benzoyloxymethyl-1,3-cyclohexadiene
Authors: Ogawa Seiichiro , Toyokuni Tatsushi , Ara Masayasu , Suetsugu Masaru , Suami Tetsuo 
Published: July 2006

Abstract
The title substituted 1,3-cyclohexadiene was prepared in three steps from the readily available Dl-1,2-di-O-acetyl-(1,3/2)-3-bromomethyl-5-cyclohexene-1,2-diol. Epoxidation of it with m-chloroperoxybenzoic acid in 1,2-dichloroethane afforded several stereoisomers of the biologically interesting highly oxygenated cyclohexane derivatives.
Methylation of Deoxynucleotides with Trimethyl Phosphate in Aqueous Phase
Authors: Tanabe Toshizumi , Yamauchi Kiyoshi , Kinoshita Masayoshi 
Published: July 2006

Abstract
Action of trimethyl phosphate on thymidine 5′-phosphate, deoxycytidine 5′-phosphate, deoxyadenosine 5′-phosphate, and deoxyguanosine 5′-phosphate at 37–60 °C, and pH 7–10 gave their methyl esters and base-methylated derivatives. Esterification took place in all deoxyribonucleotides to the almost same extent and its rate was enhanced by the reaction temperature, while being independent of pH in the range 7–10. On the other hand, methylation of the base moieties was affected by both the reaction temperature and pH of the reaction medium. The reactivity order of the four kinds of base moieties w s; at pH 7, cytosine base (N-3)&gt;guanine base (N-7)&gt;adenine base (N-1)&gt;&gt;thymine base (N-3); at pH 10, thymine base (N-3)&gt;guanine base (N-1&gt;N-7)&gt;cytosine base (N-3)&gt;adenine base (N-1).
Potassium Fluoride on Alumina. An Efficient Solid Base for Elimination, Addition, and Condensation
Authors: Yamawaki Junko , Kawate Takehiko , Ando Takashi , Hanafusa Terukiyo 
Published: July 2006

Abstract
Alumina coated with potassium fluoride proved to be a versatile solid base for olefin- and acetylene-forming elimination, the Michael addition, aldol condensation, and the Darzens condensation.
Aryliminodimagnesium Reagents. III. The Deoxygenative Condensation with Nitroso- and Nitroarenes: Electronic Effect of Substituents on Product Distribution
Authors: Okubo Masao , Takahashi Tomoko , Koga K\={o}ji 
Published: July 2006

Abstract
Aryliminodimagnesium reagents (ArN(MgBr)2) condense with nitrosoarenes and nitroarenes giving the corresponding azoarenes and azoxyarenes, respectively. Azoxyarenes were moderately deoxygenated by treatment with excessive amounts of the reagent giving the corresponding azoarenes. The reaction of nitroarenes with differently substituted reagents afforded unsymmetrically substituted azoxy- and azoarenes: Small amounts of symmetrically substituted azoarenes, which originated from the oxidative coupling of the reagent molecules, were also isolated. The distribution of the three types of condensation products are governed by the electronic effect of substituents of both the reagents and the substrates.