bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Facile Ring Enlargement Reaction via β-Oxido Carbenoid
Authors: Taguchi Hiroaki , Yamamoto Hisashi , Nozaki Hitosi 
Published: July 2006

Abstract
A general method of transforming a cyclic ketone to the next higher ring homolog chlorinated at the α-carbon or alternatively to its parent ketone is described. Treatment of a dichloromethyllithium-carbonyl adduct 2 with butyllithium affords a β-oxido carbenoid 3 at low temperature. Upon warming, 3 decomposes to a lithium enolate 4, which is quenched with diluted hydrochloric acid to give the α-chloro ketone 5. Cycloalkanone is converted to a one-carbon ring enlarged halogenated ketone. Meanwhile, dibromomethylcarbinol 7 is transformed to the halogen-free ketone 8 via monobromo β-oxido carbenoid upon treatment with butyllithium. α-Methyl substituted ketone is exclusively converted to the β-methyl substituted homolog and therefore dl-muscone is synthesized from cyclotetradecanone according to this new method.
Stereoselective One-pot Dialkylation of gem-Dihalocyclopropanes by Means of Dialkylcopperlithiums
Authors: Kitatani Katuzi , Hiyama Tamejiro , Nozaki Hitosi 
Published: July 2006

Abstract
The transformation of gem-dihalocyclopropanes (1) into 1-alkyl-1-butylcyclopropanes (2 and 3) is established by successive treatment with dibutylcopperlithium and several electrophiles. This sequence is found to be stereochemically controllable and is successfully applied to dl-sirenin synthesis. In contrast to the reaction of dibutylcopperlithium, dimethyl- and divinylcopperlithiums convert 1,1-dibromo-2-phenylcyclopropane (1a) into 1-bromo-1-methyl- and 1-bromo-1-vinyl-2-phenylcyclopropanes (15a, 16a and 15b, 16b) respectively.
The Behavior of Aerosol OT in Organic Solvents
Authors: Ueno Masaharu , Kishimoto Hiroshi 
Published: July 2006

Abstract
The parameters concerning the micelle formation of Aerosol OT in organic solvents were determined. In order to determine CMC, an apparatus was constructed for the measurement of the interfacial tension between mercury and organic media. The association numbers were estimated by vapor pressure depression measurements.
Radiative Lifetimes of NH2(2A1) Produced by Photodissociation of NH3 on Irradiation with Vacuum Ultraviolet Light
Authors: Koda Seiichiro 
Published: July 2006

Abstract
NH2(\ ildeA2A1) was produced by photolysis of NH3 on irradiation with vacuum ultraviolet light. The zero pressure lifetimes were evaluated to be ca. 15 μs from the phase lag of the emission excited by modulated Xe and Kr resonance lamps. The quenching rate coefficient of NH2(2A1) for NH3 was determined to be ca. (1.6±0.3)×10−10 cm3/molecule·s.
Time-Resolved Fluorescence Study of Exciplex and Triple Exciplex in 1,4-Dicyanobenzene and Alkylnaphthalenes
Authors: Mimura Tsutomu , Itoh Michiya 
Published: July 2006

Abstract
Exciplex (DA)* and triple exciplex (DDA)* formation between 1,4-dicyanobenzene (DCB) and alkylnaphthalenes was investigated by steady-state and nanosecond time-resolved fluorescence spectroscopies at room temperature. Typical two-component decay of the exciplex and the fluorescence rise of the triple exciplex were observed in dioxane solutions of DCB and several alkylnaphthalenes. The results imply a significant dissociation process of (DDA)* to (DA)*. Triple exciplex formation via excimer (DD)* was proposed to be significant in a concentrated solution of alkylnaphthalene (&gt;10−1 M), while the triple exciplex was formed via the exciplex in a dilute solution of the electron donor.
Direct Measurement of the Rates of Ionic Dissociation by Dynamic NMR Technique. Dissociation of α-Chlorodibenzyl Sulfides
Authors: Arai Kazutaka , Oki Michinori 
Published: July 2006

Abstract
Exchange processes of diastereotopic protons of α-chlorodibenzyl sulfides were observed by means of dynamic nuclear magnetic resonance. Polar effects of solvents and substituent effects on the ease of the exchange process of protons in p,p′-disubstituted α-chlorodibenzyl sulfides indicate that the process occurs with the dissociation of the compounds into benzylic cations and chloride ion. It is possible to measure the rates of ionic dissocation by observing the change in the line shape of signals in 1H NMR spectra. The scope of the method is discussed.
The Daphniphyllum Alkaloids with A New Nitrogen Heterocyclic Skeleton
Authors: Yamamura Shosuke , Lamberton J A , Irikawa Hazime , Okumura Yasuaki , Toda Masaaki , Hirata Yoshimasa 
Published: July 2006

Abstract
The isolation and structures of six new alkaloids [yuzurine, daphnigracine, daphnigraciline, oxodaphnigracine, oxodaphnigraciline, and epioxodaphnigraciline] are described. The structure of yuzurine, which has been elucidated by means of an X-ray crystallographic analysis of the corresponding methiodide, is in full agreement with its spectral data. The structures of the other five alkaloids, all of which were isolated from the plant Daphniphyllum gracile Gage collected in New Guinea, were deduced on the basis of an exhaustive comparison of their spectral data coupled with chemical evidences. Finally, a plausible biogenesis of these alkaloids with a new type of nitrogen heterocyclic skeleton is discussed.
Layered Compounds. XLIII. Syntheses and Properties of [2.2]Naphthaleno-and [2.2]Anthraceno-heterophanes
Authors: Otsubo Tetsuo , Mizogami Shigeyoshi , Osaka Norihisa , Sakata Yoshiteru , Misumi Soichi 
Published: July 2006

Abstract
Several [2.2]naphthaleno- and [2.2]anthraceno-heterophanes were synthesized by cross-breeding Hofmann degradation of the corresponding two quaternary ammonium hydroxides. Two isomers, anti- and syn-forms, were obtained for [2.2](1,4)naphthaleno(2,5)thiophenophane, and one isomer, anti-from, for the [2.2](1,4)anthraceno homologue. The structures of the heterophanes were determined by variable temperature NMR analysis. Transannular π-electronic interactions between the condensed aromatic ring and the heteroaromatic ring were examined on the basis of electronic and emission spectra. The thiophene ring interacts more strongly with the condensed aromatic ring than the furan ring. For anthracenophanes, 9,10-bridged system shows more effective interaction than 1,4-bridged one.
A Reductive Elimination of Steroidal Diol Monoesters with Zinc Giving the Corresponding Olefins
Authors: Goto Giichi 
Published: July 2006

Abstract
Steroidal cis-diol monoacetates (1,9,11, and 13) were refluxed with zinc powder in acetic acid to give the corresponding olefins (2,10,12, and 14) in good yield. Under the reaction conditions, no reaction occurred with diol diacetates (1b: R1=R2=H, R3=R4=Ac and 1m: R1=C6H5, R2=H, R3=R4=Ac) and trans-diol monoacetates (15 and 16). Acyclic erythro and threo diol monoacetates (17 and 19) underwent highly stereoselective reduction affording 18 and 20, respectively. The olefin-forming elimination proceeded with syn-elimination of a cyclic orthoacetate intermediate (21). The effect of some metals on the reduction and the behavior of a number of esters (26) and orthoesters (27) were also investigated.
Purification of Xylenol Orange by the High-Speed Liquid Chromatography
Authors: Nakada Shoji , Yamada Mutsuo , Ito Tasuku , Fujimoto Masatoshi 
Published: July 2006

Abstract
A relatively large amount of 3,3′-bis[N,N-bis(carboxymethyl)aminomethyl]-o-cresolsulfonphthalein (Xylenol Orange, XO) is purified easily by the high-speed liquid chromatography (HSLC).
The Nuclear Quadrupole Spin-Lattice Relaxation of 35Cl in Methylammonium Hexachlorostannate(IV) and Hexachloroplatinate(IV)
Authors: Furukawa Yoshihiro , Kiriyama Hideko , Ikeda Ryuichi 
Published: July 2006

Abstract
The 35Cl nuclear quadrupole spin-lattice relaxation time, T1 in (CH3NH3)2MCl6 (M=Sn and Pt) was measured from 4.2 to 434 K in order to clarify the dynamic aspect of the phase transitions at 156 and 125 K respectively. The relaxation process in both low-temperature phases is dominated by the rotational vibration of the octahedral [MCl6]2− ions. Far above the transition point, Ttr, the T1 decreases very rapidly with an increase in the temperature. This indicates that each octahedron reorients about its threefold axis, with the activation energies of 77±3 for [SnCl6]2− ions and 95±10 kJ mol−1 for [PtCl6]2− ions. At Ttr the log(T1⁄s) vs. kK/T curve shows a distinct minimum, as in some K2PtCl6-type compounds. This anomalous behavior can be explained in terms of a soft rotary mode of the [MCl6]2− ions. The softening is estimated to be about 60%, according to Armstrong’s approach.
Polarographic Behavior of Chloramine-T in an Acidic Solution at a Rotating Platinum Electrode
Authors: Matsuda Toshio 
Published: July 2006

Abstract
The polarographic behavior of chloramine-T at a rotating platinum electrode has been investigated in an acidic solution. Chloramine-T gives a well-defined reduction wave at a relatively positive potential. This is found to be due to the reduction of the non-ionized species of N-chloro-p-toluenesulfonamide and of dichloramine-T produced by disproportionation reaction of chloramine-T. The chemical process attributed to the disproportionation reaction is involved in the electrode process. The shape of the wave which varies with the recording procedure is correlated with the change of surface conditions. At pH lower than 4, a small prewave of hypochlorous acid produced by hydrolysis is observed at a more positive side. The diffusion current of the total wave, very stable and proportional to the concentration, is due to a two-electron reduction.
Reaction between 2,2-Diphenyl-1-picrylhydrazyl and Phenols. Substituent and Solvent Effects
Authors: Nishimura Norio , Moriya Toshimichi , Okino Yoshiko , Tanabe Kazue , Kawabata Kimio , Watanabe Toshihiko 
Published: July 2006

Abstract
A kinetic study has been made of the reaction between 2,2-diphenyl-1-picrylhydrazyl and phenols in various solvents. Polar effects in the rate-determining transition state are discussed in terms of the Hammett type relationship. Remarkable solvation effects were observed. For p-methoxyphenol the reaction rate is the greatest in the solvents which do not form strong H-bond with phenols, and the smallest in aprotic H-accepting solvents. For o-methoxyphenol the rate is the greatest in protic solvents. The results are interpreted in terms of the difference in the mode of hydrogen bondings. The rate for the reaction of the radical with α-naphthol was followed in dioxane–2,2,4-trimethylpentane mixtures. The results are explained by the theory of Kondo and Tokura, indicating that the free energy depression in the ground state takes place mainly through hydrogen bonding.
Synthesis of 3(2H)-Furanones by the Iron Carbonyl-promoted Cyclocoupling Reaction of α,α′-Dibromo Ketones and Carboxamides. A Convenient Route to Muscarines
Authors: Hayakawa Yoshihiro , Takaya Hidemasa , Makino Shinji , Hayakawa Norihiro , Noyori Ryoji 
Published: July 2006

Abstract
Reaction of α,α′-dibromo ketones and N,N-dimethylcarboxamides with the aid of Fe2(CO)9 affords the corresponding reductive cyclocoupling products, 5-(dimethylamino)tetrahydro-3-furanones. In usual, the adducts derived from di-s-alkyl ketone dibromides easily eliminated dimethylamine to afford 3(2H)-furanones. N,N-Dimethylformamide (DMF), N,N-dimethylacetamide, N,N-dimethylbenzamide, and N-methylpyrrolidone have been used as dibromo ketone receptors. Thus, this general method provides a new, singleflask procedure for the preparation of the oxygen-containing five-membered ketones. The iron carbonyl-promoted 3+2 cyclocoupling reaction is interpreted as proceeding via a stepwise cycloaddition of a reactive 2-oxyallyl–Fe(II) intermediate and carboxamide. A facile conversion of such furanones to muscarine alkaloids is described.
Ion-Molecule Reactions in the Binary Mixture of Ethylene Oxide and Trioxane. I. Hydrogen Atom and Proton Transfer Reactions
Authors: Kumakura Minoru , Sugiura Toshio 
Published: July 2006

Abstract
The formation mechanism of protonated molecular ions by cross–reactions in ethylene oxide–trioxane mixtures has been studied with use of a modified time-of-flight mass spectrometer. The precursors of the product ions were determined by analysis of the fine structure of their ionization efficiency curves using deuterated ethylene oxide. Protonated ethylene oxide is formed by the hydrogen atom transfer reaction of ethylene oxide molecular ion with trioxane, and protonated trioxane by the proton transfer reaction of CHO+ (from ethylene oxide) with trioxane. In the ion-molecule reactions of ethylene-d4 oxide–trioxane mixtures, appreciable isotope effect was observed. The CHO+ from ethylene oxide is an important reactant ion as compared with that from trioxane in the proton transfer reaction, and CHO+ from ethylene oxide was suggested as a thermal reactive ion. The order of proton affinity could be estimated from the proton transfer reactions involving CHO+. It was found that the proton affinity of trioxane is smaller than that of ethylene oxide.
The Effect of 1,10-Phenanthroline on the Rate of Xylenol Orange Indicator Color Change
Authors: Wada Hiroko , Ishizuki Tomosuke , Nakagawa Genkichi 
Published: July 2006

Abstract
1,10-Phenanthroline(phen) accelerates the rate of the color change of Xylenol Orange(XO) in the copper(II)–EDTA titrations due to the formation of a mixed-ligand complex, (Cuphen)2xo. The rate of the substitution reaction of Cu2xo with 1,10-phenanthroline or with EDTA in the presence of 1,10-phenanthroline has been determined by the stopped-flow method over the pH range of 6.9–7.6 at μ=0.1 (KNO3) and 25±1°C. At 6.2×10−5–1.2×10−3M 1,10-phenanthroline, the rate-law is expressed as –d[(Cu2xo)′]/dt=k1[H][(Cu2xo)′]. The reaction mechanism proposed is (Remark: Graphics omitted.), and k1=5.5×107 M−1 s−1. By the addition of 2.5×10−6–10−5 M 1,10-phenanthroline, copper(II) can be titrated with EDTA at room temperature with XO as an indicator.
Formose Reactions. IV. The Formose Reaction in Homogeneous Systems and the Catalytic Functions of Calcium Ion Species
Authors: Shigemasa Yoshihiro , Shimao Masayuki , Sakazawa Chikahiro , Matsuura Teruo 
Published: July 2006

Abstract
By using the previously developed analytical method of oxidation-reduction potential measurement, the formose reaction homogeneously-catalyzed by calcium formate-potassium hydroxide at pH 10.5–12.0 was found to proceed as effectively as that heterogeneously-catalyzed by calcium hydroxide. Other calcium salts, including chloride, bromide, acetate, and propionate, could be used in place of calcium formate. Kinetic studies with the calcium formate–KOH system showed a linear dependence of the concentration of the dissolved calcium ion species on the induction period (Tmin) and the formose-forming period (Tmax–Tmin) at a given pH. From the results, the relationships, Tmin=a[CaOH+]+c and Tmax–Tmin=a[CaOH+]+b[Ca(OH)2]+c, were obtained, suggesting that CaOH+ is the principal catalytic species in the induction step, while both CaOH+ and Ca(OH)2 (or OH−) are present in the formose-forming step. The effects of various factors on both steps and the sugar yield were also examined.
Syntheses of Gramicidin S Analogs Containing δ-Aminovaleric Acid. [5–1′-δ-Aminovaleric Acid]-Gramicidin S and [5–1′, 5′-1-Bis(δ-Aminovaleric Acid)]-Gramicidin S
Authors: S\={o}fuku Sh\={o}suke , Yoshida Akio , Baba Hiroki , Muramatsu Ichiro 
Published: July 2006

Abstract
Gramicidin S (GS) analogs, [5–1′-(δ-aminovaleric acid]-GS dihydrochloride (XIII) and [5–1′, 5′–1-bis(δ-aminovaleric acid)]-GS dihydrochloride (XIX), were synthesized. Both peptides are the analogs in which one or two l-prolyl-l-valyl residues of GS are replaced with one or two δ-aminovaleric acid residues. The spectra of optical rotatory dispersion (ORD) and circular dichroism (CD) of XIII and XIX were measured. The molar optical rotation of XIII is smaller than that of GS, but its ORD spectrum resembles that of GS. Analog XIII shows some antimicrobial activity, but not the analog XIX.
Substitution on Carbenoid Carbon of α-Halocyclopropyllithium. A Novel Stereoselective Synthesis of Geminally Substituted Cyclopropanes
Authors: Kitatani Katuzi , Yamamoto Hajime , Hiyama Tamejiro , Nozaki Hitosi 
Published: July 2006

Abstract
The halogen atom of the title carbenoids is susceptible to displacement by butyllithium. 1-Butyl-1-lithiocyclopropanes are formed, in which the butyl group occupies the less hindered site trans or exo position). The new reaction provides a means for the preparation of geminally disubstituted cyclopropanes with high degree of stereoselectivity.
Preparation of Perfluoroalkylated Benzoheterocyclic Compounds Using Hexafluoro-1,2-epoxypropane
Authors: Ishikawa Nobuo , Sasaki Shigekuni 
Published: July 2006

Abstract
Utilizing the high reactivity of hexafluoro-1,2-epoxypropane (HFPO, hexafluoropropylene oxide), several new benzoheterocyclic compounds containing CF3 and C2F5 were prepared as follows: (1) 2-(pentafluoroethyl)benzoxazoles by treating 2-aminophenols with HFPO/Et3N, followed by dehydrating cyclization, (2) 3-(trifluoromethyl)2H-1,4-benzoxazin-2-ones, 3-(trifluoromethyl)-2(1H)-quinoxalinone and 2-fluoro-2-(trifluoromethyl)-2,3-dihydro-1,4-benzothiazin-3-one by reactions of ortho-bifunctional benzenes with HFPO, and (3) 2-(pentafluoroethyl)-4H-3,1-benzoxazin-4-one by treating anthranilic acid with HFPO/Et3N.
An ESR Study of Photo-Induced Electron Transfer Reaction between Zinc(II)–Tetraphenylporphyrin and p-Benzoquinone in Solutions
Authors: Shiozawa Masayuki , Yamamoto Haruhiko , Fujita Yuzaburo 
Published: July 2006

Abstract
The titled reaction was studied, by means of the ESR technique at room temperature, as a model reaction of the primary process in the photosynthesis. Two kinds of radicals were observed in dichloromethane upon illumination with light of the porphyrin excitation; the zinc–tetraphenylporphyrin cation radical and the semiquinone neutral radical.
1,3-Dithian-2-one Tosylhydrazone. Synthesis and Carbenoid Decomposition
Authors: Obata Naruyoshi 
Published: July 2006

Abstract
1,3-Dithian-2-one tosylhydrazone was prepared by the reaction of potassium 3-tosyldithiocarbazate and 1,3-dibromopropane. Carbenoid reactions of the tosylhydrazone were investigated.
Statistical Thermodynamics of Liquid Mixtures
Authors: Tokiwano Kazuo , Arakawa Kiyoshi 
Published: July 2006

Abstract
A statistical thermodynamic theory of binary liquid mixtures has been worked out on the basis of the equivalent free volume defined without use of lattice model. A liquid mixture is regarded as a mixture of hard spheres immersed in a uniform background potential. The total free energy is expressed as the sum of terms given by the analytical solution of the generalized Percus-Yevick equation for the hard sphere mixture and the term resulting from the uniform background potential. Thermodynamic functions are in a simple form convenient for practical applications. The nature of the equivalent free volume for the mixture which consists of molecules differing in size is elucidated. The energy interaction parameters and excess thermodynamic functions for eight binary mixtures composed of nonpolar molecules are calculated, and the results are discussed.
ENDOR Studies on Low-Symmetry Triphenylmethyl with ortho- or para-Methoxy Substituents
Authors: Ishizu Kazuhiko , Mukai Kazuo , Shibayama Atsuko , Kondo Kyoko 
Published: July 2006

Abstract
ENDOR observations were carried out for several triphenylmethyl derivatives with ortho- or para-methoxy substituents. The alteration of the spin-density distribution caused by steric hindrance, in particular, due to the low symmetrical substitution, was investigated. Using a revised MO parameter proposed by Kulkarni, McLachlan MO calculations were carried out and the twisting angles of the hindered phenyl groups are estimated.
Simultaneous Determination of the Atomic Ratio between C, H, O, and N by the Pyrolytic Sulfurization Method
Authors: Tsuji Katsuya , Fujinaga Kaoru , Hara Tadashi 
Published: July 2006

Abstract
From a sample subjected to pyrolytic sulfurization in a sealed quartz tube, the evolved gases, carbon disulfide, carbon monoxide, carbon dioxide, carbonyl sulfide, hydrogen sulfide, and a nitrogen molecule were simultaneously estimated. Determination of the atomic ratio between C, H, O, and N was carried out by means of three calibration curves obtained by use of glycine, l-glutamic acid, l-citrulline, and fumaric acid. They are applicable to carboxylic acids and the other compounds, but not to compounds including nitro and/or sulfo groups.
The Absolute Configuration and Circular Dichroism of the (−)260-Diammine((S)-1-N-methyl-1,2-propanediamine)platinum(II) Ion, (−)260-[Pt(NH3)2(N1-Me-(S)-pn)]2+
Authors: Nakayama Yasuji , Matsumoto Keiji , Ooi Shun’ichiro , Kuroya Hisao 
Published: July 2006

Abstract
The optical resolution of [Pt(NH3)2(N1-Me-(S)-pn)]Cl2 is effected by using silver di-μ-(+)-tartrato(4−)-bis(antimonate(III)) (Ag2[Sb2(+)-tart2]) as the resolving agent. X-Ray structure analysis of the less soluble diastereoisomeric salt, (+)350-[Pt(NH3)2(N1-Me-(S)-pn)][Sb2(+)-tart2]·H2O, revealed that the asymmetric secondary nitrogen is of the R configuration. The crystal is orthorhombic, with a P212121 space group, a=19.302(7) Å, b=14.791(4) Å, c=7.925(2) Å, and Z=4. The structure was determined from counter intensity data and refined to R 0.049 using the least-squares method for 1955 independent non-zero reflections. The Pt atom has a square-planar coordination with 4 N atoms and both the N–CH3 and C–CH3 groups are equatorial with respect to the chelate ring. The circular dichroism spectrum of R-[Pt(NH3)2(N1-Me-(S)-pn)](ClO4)2, which was obtained from the less soluble di-μ-(+)-tartrato(4−)-bis(antimonate(III)) salt, is presented and discussed on the basis of the distribution of the possible conformers, the relative abundances of which were infered from 13C NMR data.
13C-NMR-Spektren von thermischen Oligomeren des Cyclopentadiens
Authors: Nakagawa Kiyoshi , Iwase Shoji , Ishii Yasutaka , Hamanaka Sawako , Ogawa Masaya 
Published: July 2006

Abstract
Die zwei Isomere des Dicyclopentadiens und vier Isomere des Tricyclopentadiens werden isoliert und ihre 13C-NMR-Spektren werden vorgelegt, wobei die Trimerisationsstufe des Cyclopentadiens systematisch in allen Einzelheiten behandelt wird. Die 13C-NMR-Spektren von Oligomeren des Cyclopentadiens werden durch Vergleich mit Spektren von Vergleichssubstanzen zugeordnet. Es ist beachtenswert, dass zwei neue Stereoisomere des Tricyclopentadiens isoliert und nachgewiesen werden.
Coenzyme Models. IX. Micellar Catalysis of Isoalloxazine (Flavin) Oxidation of Dithiol
Authors: Shinkai Seiji , Kunitake Toyoki 
Published: July 2006

Abstract
The influence of micelles on the reaction of isoalloxazines and 1,4-butanedithiol(BDT) was studied. The pKa of BDT was lowered by 0.3 pK unit in the presence of the hexadecyltrimethylammonium bromide(CTAB) micelle, indicating the formation of “hydrophobic ion pairs.” The apparent second-order rate constant for the reaction of 3-methyl-10-ethylisoalloxazine and BDT increased by 18-fold on addition of CTAB(3 mM). The UV-visible spectrum of 3-hexadecyl-10-butylisoalloxazine in the presence of the CTAB micelle was similar to that in organic solvents, the rate being enhanced by more than 400-fold as compared with that in a nonmicellar system. Anionic(SDS) and nonionic(Brij-35) micelles suppressed the reaction. The results show that the flavin oxidation of dithiol is facilitated by the environments of the CTAB micelle.