bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regioselective Preparation of Allylic Sulfones by Palladium-Catalyzed Reactions of Allylic Nitro Compounds with Sodium Benzenesulfinate
Authors: Ono Noboru , Hamamoto Isami , Kawai Takashi , Kaji Aritsune , Tamura Rui , Kakihana Masato 
Published: July 2006

Abstract
Treatment of allylic nitro compounds with sodium benzenesulfinate in the presence of 5 mol% of Pd(PPh3)4 in N,N-dimethylformamide (DMF) at 20–70 °C for 1–10 h resulted in the formation of allylic sulfones with predominance of kinetically controlled products. The product distribution is mainly controlled by the electronic nature of substituents of an allyl unit, and the isomerization to the thermodynamically-stable isomers is negligible. On the other hand, the palladium-catalyzed sulfonylation of allylic acetates with sodium benzenesulfinate is accompanied by the isomerization to give the thermodynamically-controlled products selectively. These results can be explained by assuming that allylic nitro compounds are more reactive to the palladium catalyst than allylic acetates and sulfones.
Synthesis and Reactivity of N-Trifluoromethyl-N-nitrosotrifluoromethanesulfonamide as a New Type of Trifluoromethylating Agent
Authors: Umemoto Teruo , Ando Akira 
Published: July 2006

Abstract
N-Trifluoromethyl-N-nitrosotrifluoromethanesulfonamide (TNS-Tf) was synthesized in a 58% yield by the reaction of trifluoronitrosomethane with hydroxylamine followed by the treatment with trifluoromethanesulfonyl fluoride in the presence of a base. TNS-Tf was demonstrated to be an effective trifluoromethylating agent photochemically or thermally for aromatics, thiols, disulfides, and uridine derivatives. The insertion reaction by two trifluoromethyl groups of TNS-Tf to the sulfur-sulfur bonds was observed in the reaction with disulfides having electron-withdrawing groups, giving 2 mols of trifluoromethylthio compounds. Furthermore, TNS-Tf served as a good reagent for mild and convenient in situ generation of trifluoromethylcopper complex which converted iodoaromatics to trifluoromethyl-substituted aromatics in good yields. Similarly, N-trifluoromethyl-N-nitrosononafluoro-1-butanesulfonamide (TNS-Nf) was synthesized in a 36% yield. The examination of the reactivity indicated that this type of N-nitroso sulfonamides became to be sources of both perfluoroalkyl radicals contained.
Isolation of Dithiolanylium Salts and Their Conversion to Ketene Dithioacetals and Ortho Esters
Authors: Okuyama Tadashi , Fujiwara Wataru , Fueno Takayuki 
Published: July 2006

Abstract
Various 2-substituted 1,3-dithiolan-2-ylium perchlorates (1) were prepared by the reaction of 1,2-ethanedithiol with acyl chlorides in the presence of perchloric acid. Treatments of 1 with triethylamine gave 2-alkylidene-1,3-dithiolane (2) when the 2-substituent was a primary or secondary alkyl group. 2-Aryl derivatives of 1 were converted to ortho esters by the reaction with methanol in the presence of silver nitrate. 1,3-Dithian-2-ylium perchlorates and 2-alkylidene-1,3-dithianes were also prepared similarly from 1,3-propanedithiol.
Adsorption of Cobalt(II) Ions on Crystalline Hydrous Titanium Dioxide Fibers at 298 to 423 K
Authors: Komatsu Y\={u} , Fujiki Yoshinori , Sasaki Takayoshi 
Published: July 2006

Abstract
The distribution of cobalt(II) ions between crystalline hydrous titanium dioxide fibers and aqueous solutions has been investigated. The adsorption behavior of cobalt(II) ions is explained in terms of their ion exchange with hydrogen-ions in the fibers. The distribution coefficients of cobalt(II) ions, Kd, increased with increasing temperature at 298–373 K. Slopes of the plots of logKd vs. pH for 398–423 K were ca. +1.6, which was somewhat lower than those for 298–373 K: +2.0. X-Ray powder diffraction patterns indicate that the fibers hold a layer structure up to 373 K but change to anatase or its precursor above this temperature.
Synthesis of Selenoxides by Oxidation of Selenides with t-Butyl Hypochlorite, and Its Application for Synthesis of Optically Active Selenoxide
Authors: Kobayashi Michio , Ohkubo Hiromi , Shimizu Toshio 
Published: July 2006

Abstract
An effective synthesis of selenoxides by the oxidation of selenides with t-butyl hypochlorite in the presence of methanol and pyridine followed by hydrolysis is descrived. This oxidation method is particularly effective for the oxidation of selenides which possess electron-withdrawing groups. A synthesis of partially optically active selenoxide with bulky substituents can be achieved using a novel oxidation method.
Phase Transition of N-Acyl Amino Acids with Different Acyl Group
Authors: Miyagishi Shigeyoshi , Matsumura Seiichi , Asakawa Tsuyoshi , Nishida Morie 
Published: July 2006

Abstract
The solid-liquid phase transitions of N-acyl amino acids with different acyl groups were investigated using a differential scanning calorimeter and an infrared spectrophotometer. The enthalpy and entropy changes of the transition increased by 3–5 kJ mol−1 and 8–10 J K−1mol−1, respectively, for an additional methylene group in N-acylglycine, and 7 kJ mol−1 and 18 J K−1mol−1, respectively, in the N-acyl-l,-alanine series. The same thermodynamic quantities of N-acylvalines were only slightly dependend on the acyl chain length, while they varied irregularly for the N-acylleucine series. Both the enthalpy and entropy were smaller for the l-form than for its racemic isomer in the N-acylleucines (C12 and above) and N-acylvalines. The differences of the thermodynamic quantities between the l- and Dl-forms seems to result mainly from the difference of the molecular packing in the solid state.
In Situ X-Ray Observation on the Intercalation of Weak Interaction Molecules into Perovskite-Type Layered Crystals (C9H19NH3)2PbI4 and (C10H21NH3)2CdCl4
Authors: Dolzhenko Yuri I , Inabe Tamotsu , Maruyama Yusei 
Published: July 2006

Abstract
The intercalation-deintercalation process of weak interaction organic molecules such as 1-chloronaphthalene and o-dichlorobenzene into highly oriented polycrystalline (C10H21NH3)2CdCl4 films and hexane into (C9H19NH3)2Pbl4 single crystals has been observed in situ by using X-ray technique. The process is highly reversible. Increasing of interlayer spacing is in reasonable agreement with the size of the intercalated molecules and corresponds to the parallel orientation of aromatic ring planes or hexane chains in between two paraffin layers of the host crystals.
Nanosecond Laser Photolysis of N-Methylindole in Acetonitrile
Authors: Kanamaru Nobuaki , Tanaka Jiro 
Published: July 2006

Abstract
Nanosecond laser photolysis (nslp) of N-methylindole (NMI) was investigated using XeCl laser (308 nm) so that excitation is performed at the red edge of the first absorption band. At least three transient absorptions were observed i.e. those to be ascribed to Sn←S1, Tn←T1 transitions and ion-pair like species with peaks at ≈700 nm, ≈460 nm, and ≈380 nm, respectively. The transient absorptions were found to be produced by monophotonic processes. The lifetimes of the triplet state and the ion pair were determined to be ≈3.1 μs and ≈29 μs, respectively, in degassed solutions. Transient photoconductivity (tpc) measured on the same system indicated that there are both rise and decay components. Its fastest decay component of ≈26 μs, is close to that of the transient absorption ascribed to the ion pair. This result provides another example of monophotonic electron ejection through fluorescent states of aromatic amines in polar solvents, such as, acetonitrile.
Pulse Radiolysis Study of Positive-Charge Transfer in Freon-Mixture Matrix at 77 K
Authors: Kira Akira , Imamura Masashi , Tagawa Seiichi , Tabata Yoneho 
Published: July 2006

Abstract
The pulse radiolysis of a Freon mixture (FM), an equivolume mixture of CFCl3 and CF2BrCF2Br, at 77 K gave transient absorption bands with peaks at 360, 490, and 530 nm, whose decay was enhanced by cation scavengers: propylamine, triethylamine, N,N′-diethylaniline, and biphenyl. The degree of the enhancement was independent of the difference in the ionization potential between the matrix and the solute molecules. In the FM matrix, positive-charge transfer from biphenyl cations to some other solute molecules showed energy dependence similar to that observed in the s-butyl chloride matrix. The rate of inter-solute positive-charge transfer was faster in the FM matrix than in the s-butyl chloride matrix. These results were discussed in relation to current electron transfer theories.
Thermal Diffusion of Prototropic Ions in Water
Authors: Takeyama Naokata , Nakashima Kimie 
Published: July 2006

Abstract
Regarding the Soret effect of prototropic ions of H+ and OH− in dilute aqueous solutions, it has been mentioned that heat-of-transport values for ions are in good agreement with those of the activation energies for ionic diffusion in the Arrhenius expression. The physicochemical significance of these facts is discussed in relation to the inclusion of thermal diffusion terms in Kramers’ formula for ordinary diffusion flux.
Estimation of Isomer Ratio of 2,3-Alkanedione Dioxime Using High-Resolution 13C NMR in the Solid State
Authors: Kinoshita Setsuko , Wakita Hisanobu , Masuda Isao 
Published: July 2006

Abstract
High-resolution 13C NMR spectra were measured for the CH3–C(=NOH)–C(=NOH)–R (R=CH3, C2H5, n-C3H7, and n-C4H9) series in the solid state. A commercially available powder, dimethylglyoxime (R=CH3), produced two C2 signals, indicating two isomers: i.e., s-trans-(E,E) and s-cis-(E,E). The ratio of trans: cis was estimated to be 3:1.
The Nernst–Planck Type Equation in Nonequilibrium Thermodynamics
Authors: Kimizuka Hideo 
Published: July 2006

Abstract
A single-term expression of the Nernst–Planck type equation conformable with nonequilibrium thermodynamics has been presented. The equation may be applicable to treat the electric properties of the multi-ionic system, although the individual ion flux is unobservable.
New Application of Crown Ether. VII. Synthesis and Complexation Behavior of Bis(crown ether)s Consisting of a Benzocrown Unit and a Monoazacrown Unit
Authors: He Gong-Xin , Abe Akito , Ikeda Toshihiko , Wada Fumio , Kikukawa Kiyoshi , Matsuda Tsutomu 
Published: July 2006

Abstract
New bis(crown ether)s 3 consisting of a benzocrown unit and a monoazacrown unit connected by an oxyethylene linkage were synthesized. Their complexation behavior proved to be analogous to that of lariat monoazacrown ethers rather than that of bis(benzocrown ether)s.
Flocculation of Iron(III) Oxide Hydrate Sols Induced by α,ω-Type Surfactants
Authors: Esumi Kunio , Yamada Kazuki , Sugawara Toshie , Meguro Kenjiro 
Published: July 2006

Abstract
The interactions of disodium salt of bis(3-sulfopropyl) α,ω-alkanedicarboxylate(C10-α,ω and C12-α,ω) with monodispersed spherical particles of iron(III) oxide hydrate sols were studied by measuring the mean particle size, the zeta-potential and the amounts of adsorption. The sols were flocculated by the addition of small amounts of C10-α,ω and C12-α,ω. The flocks thus formed were redispersed by the further addition of these surfactants. The flocculation of sols upon the addition of α,ω-type surfactants occurred over a wider concentration range than upon the addition of an ordinary surfactant, such as sodium dodecyl sulfate(SDS). Furthermore, the mechanism of redispersion upon the addition of α,ω-type surfactants is different with the two fold adsorption layer in SDS.
Studies of Collectors. VII. Flotation of Heavy Metal Ions by Using Colored Surfactant
Authors: Koide Yoshifumi , Sato Shigekazu , Yamada Kimiho 
Published: July 2006

Abstract
Colored surfactants containing complex radicals(R-Bc, R-Bs, R-Sh, R-S, R-C, R-Ha, and R-Hb) were applied as ion-flotation collectors and foam-fractionation collectors. The extent of floatabilities for the colored complexing surfactants and metal ions was easily recognized by the degree of discoloration. R-Bc, R-Bs, and R-Sh with low HLB values formed floatable complexes in pH 6–9 with Cu2+, Cd2+, Hg2+, Pb2+, and Sr2+. The residual concentrations of R-Sh, R-Bc, and R-Bs were below 0.1 ppm; however, these concentrations gradually increased after obtaining a minimum concentration of metal ions. Since R-C, R-Ha, and R-Hb had high HLB values, they easily floated Cu2+, Pb2+, and Cd2+ by foam fractionation. The concentrations of R-C, R-Ha, and R-Hb in foams or aqueous solutions were correlated to their foaming abilities.
Behavior of the Cadmium Ion-Selective Electrode in Alcohol–Water Mixtures
Authors: Motonaka Junko , Konishi Hiroshi , Ikeda Sanae , Tanaka Nobuyuki 
Published: July 2006

Abstract
In an investigation on the behavior of a cadmium ion-selective electrode in methanol–water and ethanol–water mixtures, potential measurements were carried out with a digital pH/mV meter, a cadmium ion-selective indicator electrode and a silver–silver chloride reference electrode. The calibration curves, slopes of the response, response times, effects of temperature, relation between the potential and the pH-meter reading and selectivity of the electrode were discussed. The response of cadmium ions (electromotive force) was linear between 10−7–10−2 mol dm−3 in water. However, the linear range became narrower with an increase in the alcohol content. The slopes in alcohol–water mixtures (27–33 mV/decade in methanol–water mixtures, 21–29 mV/decade in ethanol–water mixtures) were nearly equal to the Nernstian slope (29.6 mV/decade). The response times of the cadmium ion-selective electrode in 99 v/v% methanol and in 99 v/v% ethanol were somewhat long, but were still within 5 min for all solutions consisting of 10−5–10−1 mol dm−3 of cadmium ions. The selectivity of the cadmium ion-selective electrode in various media was examined by the mixed-solution method using potassium, sodium, calcium and magnesium ions as the interfering ions. It was found that a cadmium ion-selective electrode could be used to determine cadmium ions in an alcohol–water solution, although the response time became longer and the linear range of the response became narrower with an increase in the alcohol content.
On the Mechanism of Transfer of Sodium Ion across the Nitrobenzene/Water Interface Facilitated by Dibenzo-18-crown-6
Authors: Kakutani Tadaaki , Nishiwaki Yoshinori , Osakai Toshiyuki , Senda Mitsugi 
Published: July 2006

Abstract
The question of the site of ionophore–ion complex formation, whether it is in the organic phase (EC), in the aqueous phase (CE), or at the interface (E), in the transfer facilitated by dibenzo-18-crown-6 of sodium ion across the nitrobenzene/water interface was studied by kinetic analysis of the ion transfer using a.c. polarographic method. The results indicate that the interface reaction mechanism (E) is the most probable of the three.
Electrochemical Reduction of Carbon Dioxide Using Iron–Sulfur Clusters as Catalyst Precursors
Authors: Nakazawa Makoto , Mizobe Yasushi , Matsumoto Yoichi , Uchida Yasuzo , Tezuka Meguru , Hidai Masanobu 
Published: July 2006

Abstract
The potential-current relationships of DMF solutions of a series of iron–sulfur compounds have revealed that in the presence of clusters [Fe4S4(SR)4]2− (R=PhCH2 or But) and [M2Fe6S8(SEt)9]3− (M=Mo or W) the electroreduction of CO2 proceeds at the potential shifted by about 0.7 and 0.5 V, respectively, to the positive direction compared to the potential at which CO2 is reduced without any catalyst. When controlled potential electrolysis of a DMF solution containing [Fe4S4(SCH2Ph)4]2− was carried out under CO2 at −2.0 V vs. SCE, phenylacetate and formate were formed as the products resulting from CO2 reduction. The cubane structure of this cluster collapsed rapidly under these conditions. However, when excess amount of PhCH2SH was added to the catholyte, the cluster structure was preserved during a relatively long period of electrolysis, and the yield of phenylacetate increased but that of formate decreased compared with the reaction in the absence of free PhCH2SH.
Studies on Nucleosides and Nucleotides. XII. Carbon-Chain Extension at 5′-Position of Ribonucleosides
Authors: Kimura Junji , Kobayashi Hideyuki , Miyahara Osamu , Mitsunobu Oyo 
Published: July 2006

Abstract
2,6-Di-t-butyl-4-nitrophenol reacted with O2-methyluridine, N3-methyluridine or 4-triazolyl-1-(β-d-ribofuranosyl)-2(1H)-pyrimidinone in the presence of diethyl azodicarboxylate and triphenylphosphine selectively at the 5′-position to give the corresponding 4-(nucleosid-5′-yl-aci-nitro)-2,6-di-t-butylcyclohexa-2,5-dienone (aci-nitro ester of nucleoside) in 39–72% yields along with varied amounts of 5′-deoxy-5′-[N,N′-bis(ethoxycarbonyl)hydrazino]nucleosides. By comparison of the reactions of pyrimidine nucleosides having free 2′- and 3′-hydroxyl groups with those of their 2′,3′-O-isopropylidene derivatives, the ratio of aci-nitxo ester to 5′-deoxy-5′-hydrazinonucleoside was affected by the protecting groups as well as the time required for the addition of diethyl azodicarboxylate to a solution of other reactants. Similarly, N1,N6,2′3′-O-tetrabenzoyladenosine afforded the expected aci-nitro ester in 83% yield. The aci-nitro esters prepared were successfully reacted with stabilized phosphoranes such as (ethoxycarbonylmethylene)triphenylphosphorane or (acetylmethylene)triphenylphosphorane giving 1-[(E)-β-d-ribo-hept-5-enofuranosyl]- or 1-[(E)-β-d-ribo-oct-5-enofuranosyl]-pyrimidines and -purines. When the two stage reactions were carried out by one-pot procedure without isolation of aci-nitro esters, overall yields of alkenofuranosylpyrimidines were markedly improved.
Syntheses of Some 6-Oxa- and 2,8-Dioxabicyclo[3.2.1]octanes in Connection with the Daphniphyllum Alkaloids
Authors: Nishiyama Shigeru , Ikeda Yoichi , Yamamura Shosuke 
Published: July 2006

Abstract
In connection with the daphniphyllum alkaloids, some 6-oxa- and 2,8-dioxabicyclo[3.2.1]octanes, which are included as a partial structure of daphmacrine and codaphniphylline, have been synthesized starting from geraniol.
A Molecular Orbital Approach to the Effect of Acid and Base on Mutarotation of d-Glucose
Authors: Imamura Akira , Okajima Toshiya , Kanda Katsuya 
Published: July 2006

Abstract
Molecular orbital calculations were performed for the study of the mechanism of the mutarotation of d-glucose (in Fig. 1) by the CNDO/2 method. The calculated results for a proposed mechanism are in good agreement with the experimental results in relation to the effect of the acid and the base, suggesting the validity of the proposed mechanism of mutarotation.
X-Ray Crystal Structures of 2,4-Dimethyl-4,4a-dihydro-1H-[1,3,5]triazino[1,2-a]quinoline-1,3,6(2H,5H)-trione and Its Dehydrogenated Derivative. Bond Length and EI Mass Fragmentation
Authors: Sawada Masami , Tanaka Takanori , Takai Yoshio , Furukawa Yoshiro , Hanafusa Terukiyo , Misumi Soichi 
Published: July 2006

Abstract
The crystal structures of the cyclic adduct 1 of 4-quinolinone with methyl isocyanate and its dehydrogenated derivative 2 have been determined by X-ray crystal structure analysis. Both crystal structure data of the C–N bond lengths in the triazinedione-ring skeleton suggest which bonds are broken in the initial EI mass fragmentation followed by the subsequent loss of a neutral MeNCO moiety.
Color Reaction between Indium(III) and o-Hydroxyhydroquinonephthalein, and Its Application
Authors: Mori Itsuo , Fujita Yoshikazu , Fujita Kinuko , Koshiyama Yozo , Kawabe Hiroshi , Tanaka Takeshi , Munakata Reiko 
Published: July 2006

Abstract
Color reaction between indium(III) and o-hydroxyhyroquinonephthalein(Qnph) in the presence of a cationic surfactant was studied, and its application for the spectrophotometry and photometric titration of indium(III) was discussed. The color reaction between Qnph and indium(III) in the presence of hexadecyltrimethylammonium chloride(HTAC) was stable in weakly acidic media. The calibration curve was rectilinear in the range of 0–10 μg/10 cm3 of indium(III) at 560 nm, and the apparent molar absorption coefficient was 1.3×105 dm3 mol−1 cm−1. The Sandell sensitivity was 0.0008 μg/cm2 for indium(III).
Concentration Quenching of Fluorescence from Bridged Synthetic Porphyrins
Authors: Maruyama Kazuhiro , Morikawa Soichi , Osuka Atsuhiro 
Published: July 2006

Abstract
Concentration quenching phenomena of singly and doubly bridged porphyrins and their zinc and magnesium complexes were studied. Hypothetical nonfluorescent dimer trap was suggested to be not a coplanarly stacked face-to-face dimer but a loosely interacting pair.
Substituent Effects. XVI. Acetolysis of 2-Phenylethyl Tosylates
Authors: Fujio Mizue , Funatsu Kimito , Goto Mutsuo , Seki Yoji , Mishima Masaaki , Tsuno Yuho 
Published: July 2006

Abstract
The acetolysis rates of 2-arylethyl tosylates were determined for a series of aryl substituents. The non-linear substituent effect was reasonably accounted for on the basis of two linear LArSR relationships; one for the aryl-assisted (FkΔ) and one for the unassisted (ks) processes, respectively. A precise dissection of the apparent substituent effect into individual effects for both processes was achieved in this manner. The substituent effect on the ks process can be described as a linear function of σ° with a small ρs of −0.19, and that on the FkΔ process in terms of the LArSR Eq., with ρΔ=−3.87 and an rΔ=0.631. The use of σ+ for the FkΔ process failed to give any reasonable dissection. The r value for this FkΔ process is essentially identical to that for the neophyl solvolysis. The unique r value of 0.6 is concluded to be characteristic of β-arylassisted ionization processes in general.
A Fast Kinetic Study of Formation and Decay of 2,2′-Azinobis(3-ethylbenzothiazole-6-sulfonate) Radical Cation in Aqueous Solution
Authors: Maruthamuthu Pichai , Venkatasubramanian Lakshmanan , Dharmalingam Periasamy 
Published: July 2006

Abstract
The kinetics of oxidation of 2,2′-azinobis(3-ethylbenzothiazole-6-sulfonate) (ABTS) to the radical cation, ABTS·+ by S2O82−, HSO5−, MnO4−, Cr2O72−, Ce(IV), and molecular Cl2, Br2, and I2 and further oxidation to the dication, ABTS2+ by the above oxidants except HSO5−, Br2, and I2 have been carried out by the stoppedflow spectrophotometric technique. The first-stage oxidation was followed by monitoring the absorption of ABTS·+ at 417 nm and the second-stage oxidation, by following the disappearance of ABTS·+ or the appearance of ABTS2+ at 513 nm. Both the reactions, formation and decay of ABTS·+ were found to obey a total second-order kinetics, first-order each with respect to [ABTS] or [ABTS·+] and [oxidant]. With I2, ABTS underwent reversible reaction, the stoichiometry of which being,
I2+2ABTS\ightleftarrows2ABTS·++2I− with K=142.8,
whereasBr_2generatedonlytheradicalcationandCl_2gaveadecomposedproductviaradicalcationanddicationintermediates.ABTS^2+formedinpresenceofexcessMnO_4^-,Cr_2O_7^2-,andCe(IV)decayedasinthecaseofCl_2reactionbutinpresenceofS_2O_8^2-thedicationwasstableformorethanthreedays.IntheabsenceofexcessS_2O_8^2-,ABTS^2+wentbacktoABTS^·+,possiblyviaoxidationofwater.TheradicalcationwasconvertedbacktotheparentcompoundABTSbyreducingagentssuchasdithioniteandsulfiteions.
Preparation and Characterization of the Dicobalt(III) Complexes Containing Bridging Di-μ-hydroxo Ligands
Authors: Ama Tomoharu , Kawaguchi Hiroshi , Yasui Takaji 
Published: July 2006

Abstract
Three dicobalt(III) complexes, [(L)Co(μ-OH)2Co(NH3)4]2+ or + (L=edda, (gly)2, or nta), were newly prepared and their structures were assigned on the basis of absorption, 1H NMR, and CD spectral data. Each of them has a structure in which the chromophores of two different types are bridged with two hydroxo ligands and with two hydrogen bonds between carboxyl and amino groups. These three complexes are stable for several days in aqueous solutions.