bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthetic Studies of Rifamycins. V. A Chiral Synthesis of an Ansa-chain Compound for the C-17–C-29 Portion of Rifamycin W
Authors: Nakata Masaya , Enari Hiroyuki , Kinoshita Mitsuhiro 
Published: July 2006

Abstract
The chiral synthesis of methyl 5,7,9-tri-O-acetyl-2-C-(acetoxymethyl)-2,4,6,8,10,11,12-heptadeoxy-4,6,8,10-tetra-C-methyl-aldehydo-l-glycero-l-talo-l-manno-(E)-11-tridecenuronate 1-(dimethyl acetal) (III), a useful synthetic segment for the C-17-C-29 portion of rifamycin W, is described. The key intermediate, 3-O-(t-butyldimethylsilyl)-2,4,7-trideoxy-5,6-O-isopropylidene-2,4-di-C-methyl-aldehydo-d-glycero-d-talo-heptose (28) was synthesized in 30% yield from methyl 4,6-O-benzylidene-3-deoxy-3-C-methyl-α-d-glucopyranoside in 15 steps. The synthesis involves key steps of highly stereoselective Grignard reaction and regiospecific cis-epoxide ring-opening reaction. The condensation of 28 with 3,3-diethoxy-2-lithio-1-propene afforded about 1.6:1 excess of the “Cram” product (30, 56% yield). The desilylation of 30 followed by homogeneous hydrogenation with (Ph3P)3RhCl gave only the erythro product 34. 3,5-Di-O-benzyl-2,4,6-trideoxy-2,4,6-tri-C-methyl-l-glycero-l-manmo-heptodialdose 1-(diethyl acetal) derived from 34, condensed with the lithium reagent prepared (in ether at −95–−90 °C) from butyllithium and 3-C-(benzyloxymethyl)-3,5,6-trideoxy-5-iodo-1,2-O-isopropylidene-α-d-hexenofuranose, derived from 3-deoxy-3-C-hydroxymethyl-1,2 : 5,6-di-O-isopropylidene-α-d-allofuranose, to afford a 4 : 1 mixture of the “Cram” product and its epimer in 80% yield. The homogeneous hydrogenation of the mixture followed by the debenzylation gave the diastereomerically pure major product, which could be transformed into III in 6 steps.
Study of Ion Transport across Amphoteric Ion Exchange Membrane. I. Electroconductive Membrane Permeability
Authors: Yamauchi Akira , Tsuruyama Shigeru , Masumori Harumi , Nagata Yoshihiko , Kaibara Kozue , Kimizuka Hideo 
Published: July 2006

Abstract
Basic ion transport characteristics of a homogeneous amphoteric ion exchange membrane (Kanegafuchi Chem. Ind. 1.0-PA-29) were studied by measuring the membrane potentials and conductances. Concentration cell systems of NaCl, KCl, CaCl2, and SrCl2 with a concentration range of 10−1–10−3 mol dm−3 were studied and the electroconductive membrane permeabilities were estimated from the electrochemical data. Generally, Cl− is slightly more permeable than cations under the present experimental conditions, except the result that K+ is more permeable at low concentrations. Unlike the usual uniform cation exchange membrane of which transport characteristics to ions strongly depend upon the number of ionic charges, a “1.0-PA-29” amphoteric membrane exhibits different transport properties for the NaCl and KCl systems. In the NaCl system, the membrane was constantly anionic selective, while in the KCl system, biphasic ion selectivities were observed depending upon the external KCl concentration. Fundamental electrochemical properties of the membrane systems were discussed by examining the dependencies of membrane permeability on external electrolyte concentrations and on differences in ionic species. The present result suggests that the ionic size is one of the critical factors determining the transport characteristics across amphoteric ion exchange membrane.
Acid Catalysis of the Transformation of 1-Methoxycarbonyl-2-imidazoline to 1-Methoxycarbonyl-2-imidazolidinone, a Carboxybiotin Model
Authors: Kondo Hiroki , Miura Katsuhito , Sunamoto Junzo 
Published: July 2006

Abstract
The transformation of 1-methoxycarbonyl-2-ethoxy-2-imidazoline into 1-methoxycarbonyl-2-imidazolidinone a 1-carboxybiotin model, is facilitated by acid.
Penetration of Leucine and Norleucine into Lecithin Monolayers from Underlying Aqueous Solutions
Authors: Nakagaki Masayuki , Okamura Emiko 
Published: July 2006

Abstract
The surface pressure of the monolayers of dimyristoyl phosphatidylcholine(DMPC) on leucine and norleucine solutions was measured and the amounts of these amino acids which had penetrated into the DMPC monolayer were calculated by means of a successive approximation. Although the amounts of leucine and norleucine adsorbed onto the solution surface were nearly equal and were larger than that of lysine, the amount of leucine which had penetrated into the DMPC monolayer was remarkably small. That of norleucine was not so small, but was still smaller than that of lysine except for the region where the molecular area of DMPC is large. The partial molecular areas of amino acid, \barA2, and DMPC, \barA3, were calculated in each case. The value of \barA2, was the largest in the case of leucine and the smallest in the case of lysine, which means that the area occupied by lysine is smaller than that of norleucine because the interaction of ε-amino group with DMPC contracts the mixed monolayer. The change in the value of \barA3 due to the interaction with amino acid, however, was not large, which means that the change in the state of DMPC itself is not large and rather independent of the kind of amino acid.
Polarized Absorption Spectra of Aromatic Radicals in Stretched Polymer Film. IV. Radical Ions of 9-Substituted Anthracenes
Authors: Hiratsuka Hiroshi , Nakamura Hitoshi , Tanizaki Yoshie , Nakajima Keihachiro 
Published: July 2006

Abstract
Radical ions of some 9-substituted anthracene derivatives have been prepared in polymer film by γ-irradiation at 77 K. By use of the polarized absorption spectra of these radical ions, the absorption spectra have been resolved into two components (resolved spectra), the transition moments of which are polarized parallel to the molecular long and short axes, respectively. Correlation of the characteristic absorption bands is discussed briefly.
Multiphoton Ionization Spectrum of p-Terphenyl in a Supersonic Free Jet
Authors: Murakami Jun-ichi , Okuyama Katsuhiko , Ito Mitsuo 
Published: July 2006

Abstract
The one-photon absorption spectrum of p-terphenyl vapor was observed in a supersonic free jet by using multiphoton ionization spectroscopy. In the spectrum were observed the progressions of the in-phase and out-of-phase torsional vibrations of the benzene rings. It was concluded that p-terphenyl has a planar structure in the first excited singlet state, whereas it is twisted in the ground state.
Conformation of Condensed Polycyclic Aromatic Hydrocarbons. I. The Molecular and Crystal Structure of Anthra[2,1,9,8-hijkl]benzo[de]naphtho[2,1,8,7-stuv]pentacene
Authors: Fujisawa Shoji , Oonishi Isao , Aoki Junji , Ohashi Yuji , Sasada Yoshio 
Published: July 2006

Abstract
The crystal structure of the title compound, C38H18, has been determined by X-ray analysis. The space group is Pa, with unit cell dimensions a=31.276(4), b=3.7818(4), c=21.663(3) Å, β=124.22(1)° and Z=4. The structure was solved by the direct method and refined by full-matrix least-squares methods to an R value of 0.073 for 2619 reflections. Two crystallographically independent molecules are largely distorted from a planar structure due to the repulsions between the crowded hydrogen atoms, with different conformations to each other. The molecules are stacked face-to-face by van der Waals forces to form column structures along the b axis.
Reaction Process of Vanadium Tetrachloride with Ammonia in the Vapor Phase and Properties of the Vanadium Nitride Formed
Authors: Saeki Yuzo , Shimizu Takashi , Yajima Akimasa , Matsuzaki Ryoko 
Published: July 2006

Abstract
The reaction products of gaseous VCl4 with ammonia were VCl4·4NH3 at 200 °C, VCl4·4NH3, VNx, and NH4Cl at 250–550 °C, and VNx and NH4Cl at 600–1000 °C. At 1100 °C, small amounts of VCl2 and HCl were formed in addition to VNx and NH4Cl. The N/V atomic ratio, x, of the VNx formed was 1.20 at 600 °C, 1.15 at 700 °C, 1.14 at 800 °C, and 1.13 at 900 and 1000 °C. The lattice constants of the VNx formed were shown. The reaction process of gaseous VCl4 with ammonia can be represented as follows: The reaction of gaseous VCl4 with ammonia first occurs to form VCl4·4NH3. Above about 215 °C, the reaction of VCl4·4NH3 with ammonia also occurs to form VNx. At 1100 °C, in addition to these reactions, the reaction of gaseous VCl4 with hydrogen formed by the thermal dissociation of ammonia occurs to form VCl2. On heating the VNx, formed by the vapor-phase reaction, at temperatures higher than 500 °C in an argon atmosphere, the value of x decreased with the increase in the heating temperature to 1.03 at 900–1000 °C.
SbCl5 Complexes of Pyridine N-Oxide and Trimethylamine Oxide as the Oxidizing Agent
Authors: Yamamoto Jiro , Murakami Mitushige , Kameoka Noriaki , Otani Norio , Umezu Masahiro , Matsuura Teruo 
Published: July 2006

Abstract
A 1:1 complex of pyridine N-oxide or trimethylamine oxide with SbCl5 acted as an oxidizing agent to benzyl alcohol, bezoin, furoin, and thiophenols more easily than via the oxides to give benzaldehyde, benzil, furil, and the corresponding disulfides respectively. The trimethylamine oxide–SbCl5 also oxidized p-xylene to p-tolualdehyde under nitrogen and to p-toluic acid under air.
Studies on Dissolved Metalloenzymes in Lake Water. I. Identification of Alkaline Phosphatase
Authors: Kobayashi Kensei , Iwase Kimikazu , Matsui Masahiro , Watanabe Masami , Ueda Hirotaka , Fujiwara Kitao , Haraguchi Hiroki , Fuwa Keiichiro 
Published: July 2006

Abstract
Metalloenzyme (alkaline phosphatase) dissolved in lake water has been identified by means of high performance liquid chromatography (HPLC). Water samples were collected from Lake Kasumigaura in Ibaraki, and filtered with a 0.2–0.45 μm membrane filter immediately after sampling. Filtered water was concentrated to 100–2000 fold by ultrafiltration membrane which could concentrate the components of molecular weight larger than 10000. The enzymatic activity of alkaline phosphatase was measured using p-nitrophenyl dihydrogen-phosphate as a substrate. Chelating agents added to the concentrated lake water inhibited the appearance of enzymatic activity, while the enzymatic activity was recovered with addition of zinc ion. The HPLC chromatograms of the concentrated lake water were examined, where an aqueous porous gel column was used for separation. The effluent at molecular weight of ca. 90000 showed specific activity of alkaline phosphatase. Zinc was also found in the same fraction. These facts suggest that alkaline phosphatase with the nature similar to procaryotes was present in the lake water.
Electron Transfer from Tetrakis(isocyanide)rhodium(I) Monomers, and the Oligomers to Iron(III) and Cobalt(III) Complexes. Enhancement of the Reactivity by the Oligomerization
Authors: Fukuzumi Shunichi , Nishizawa Nobuaki , Tanaka Toshio 
Published: July 2006

Abstract
Electron transfer reactions from tetrakis(isocyanide)rhodium(I) ([RhL4]+ to iron(III) complexes of the [Fe(N–N)3]3+ type (N–N=1,10-phenanthroline, 2,2′-bipyridine) proceed through precursor complexes formed between [RhL4]+ and [Fe(N–N)3]3+ with 1:1, 1:2, and 2:1 stoichiometry. A similar scheme is suggested for the reaction of bis(isocyanide)bis(triphenylphosphine)rhodium(I) with the same oxidants. The intramolecular electron transfer rate constants k1 in the 1:1 precursor complexes have been determined in MeCN at 298 K. In accordance with Marcus theory, the logk1 values are linearly related with the reduction potentials of oxidants with the theoretical slope of 8.5. The [RhL4]+ cations form oligomers in MeCN; [RhL4+]n (n=2,3), and the equilibrium constants for oligomerization have been determined. For a given oxidant [Co(bpy)3]3+ (bpy=2,2′-bipyridine), the logk1 value of [RhL4+]n increases in parallel with the HOMO energy of [RhL4+]n; monomer&lt;dimer&lt;trimer.
Argon Plasma Treatment of Packing Materials for Gas Chromatography and Comparison with Acid Wash and Dimethyldichlorosilane Treatment of Support
Authors: Oka Seiji , Yamamoto Yukio , Hayashi Koichiro 
Published: July 2006

Abstract
Argon plasma treatment of column packings for gas chromatography was examined with commercially obtained diatomaceous earth coated with several kinds of stationary liquid phases, such as squalane, Apiezon L, dioctyl phthalate, Silicone DC, and polyethylene glycol. It was found that the plasma treatment improves chromatographic properties of all the packings examined except those with polyethylene glycol. The effect of the plasma treatment is attributable to the reduction of support adsorptivity by the formation of an inert coating on the support surface. The plasma treatment of Chromosorb W coated with 5% squalane was compared with dimethyldichlorosilane (DMCS) treatment of the acid-washed (AW) support, the so-called AW-DMCS-treatment of support. Although the AW-DMCS-treatment is superior to the plasma treatment for the reduction of support adsorptivity, a complete elimination of the adsorptivity was attained by the plasma treatment of the packing having the AW-DMCS-treated support.
Asymmetric Transformation of 2-Phenyl- and 2-Chloroalkanoic Acids via Chiral Oxazolines
Authors: Shibata Saizo , Matsushita Hajime , Kaneko Hajime , Noguchi Masao , Saburi Masahiko , Yoshikawa Sadao 
Published: July 2006

Abstract
Asymmetric transformation of racemic 2-phenyl- and 2-chloroalkanoic acids via oxazolines into the corresponding optically active acids was investigated using (S)-phenylalaninol as a chiral auxiliary. The asymmetric transformation was performed by metalation of the oxazolines with butyllithium followed by protonation of the resulting lithiooxazolines. 2-Phenyl- and 2-chloroalkanoic acids were obtained in the optical yields of 29–53% and 45–73%, respectively, by the acidic hydrolysis of the chiral oxazolines thus formed. The mechanism of the asymmetric transformation was discussed.
The Conformations of Several 1-Phenylethyl and 1-Phenylpropyl Aryl Sulfoxides. Evidence for Attractive Aryl/Aryl Interaction
Authors: Kobayasm Keiji , Kodama Yoshio , Nishio Motohiro , Sugawara Tadashi , Iwamura Hiizu 
Published: July 2006

Abstract
The conformations of the diastereoisomers of 1-phenylethyl phenyl (1), 1-phenylethyl p-tolyl (2), 1-phenylpropyl phenyl sulfoxides (3) were studied by NMR spectroscopy, largely by means of the computer simulation of the lanthanoid-induced shifts. It has been suggested that the rotamer in which the aromatic group (Ar) is
4C_6H_5CH(R)–SO–Ar& 1:R=& &CH_3,& Ar=&C_6H_5
& 2:& &CH_3,& &C_6H_4CH_3(p)
& 3:& &C_2H_5,& &C_6H_5
gauche to the phenyl (Ph) and anti to the alkyl (R) group is most populated in the conformational equilibria of (RS/SR)-1, 2, 3, and (RR/SS)-3. For (RR/SS)-1 and 2, on the other hand, the most important contributor has been suggested to be the rotamer in which Ar is flanked by Ph and R. The results have been discussed in the light of the presence of attractive interactions between relevant groups.
The Electron Exchange Rates of Anthracene/Anthracene Radical Anion Ion-paired with Various Tetraalkylammonium Cations
Authors: Suga Kosaku , Aoyagui Shigeru 
Published: July 2006

Abstract
The electron exchange reaction between anthracene and its radical anion formed by the sodium reduction of the parent molecule in 1,2-dimethoxyethane, tetrahydrofuran, and a tetrahydrofuran-1,4-dioxane mixture was studied by ESR spectroscopy in the preseuce of tetraalkylammonium cations of various kinds and amounts. Analytical equations were presented to evaluate the rate constants of two competitive electron exchange reactions between anthracene and its anion, which was ion-paired in part with a tetraalkylammonium cation and in part with a sodium cation. The experimental results obeyed the theoretical equations and, consequently, yielded the electron exchange rate constants for the ion pairs of the former type, which were unaffected by the coexistence of the ion pairs of the latter type. They were of the order of 108 M−1s−1 (1 M=1 mol dm−3), a value which was one order of magnitude smaller than the rate constant for the solvent-separated ion pair of anthracene anion with sodium cation. They were smaller for tetraalkylammonium cations with longer carbon chains. These findings are discussed on the basis of the theory of Marcus.
Preparation of New Nitrogen-Bridged Heterocycles. 5. Smooth Michael Additions of 2(3H)-Indolizinone Derivatives
Authors: Kakehi Akikazu , Ito Suketaka , Wada Bunzo , Watanabe Kozo , Nishimura Kenji , Kumagai Aiichiro 
Published: July 2006

Abstract
Michael additions of some 2(3H)-indolizinone derivatives to α,β-unsaturated nitriles, esters, and an amide gave the corresponding double Michael adducts, 3,3-disubstituted 2(3H)-indolizinones, in moderate to high yields, and those to methyl vinyl ketone afforded further condensed products, spiro[cyclohexane-1,3′(2′H)-indolizin]-2′-ones, instead of the expected 1:2 adducts. On the other hand, the reactions of the indolizinones with activated ethylenes having an appropriate leaving group at the β-position or with an acetylenic ester formed unstable 1:1 Michael adducts, which were converted to stable 2-acyloxy- or 2-alkoxy-3-vinylindolizine derivatives by the treatment with some acylating or alkylating agents in comparatively good yields.
A Through-process for the Preparation of Methyl Per-O-acetyl 1-Thio-glycosides from Aldoses
Authors: Koto Shinkiti , Yoshida Toyosaku , Takenaka Kazuhiro , Zen Shonosuke 
Published: July 2006

Abstract
d-Glucose, d-galactose, d-mannose, d-xylose, l-arabinose, l-fucose, l-rhamnose, maltose, cellobiose, lactose, d-glucosamine, d-galactosamine, and d-mannosamine were converted into the corresponding methyl per-O-acetyl 1-thioglycopyranosides by way of a three-step (acetobromination, methylthioation, and acetylation) through-process in a single vessel.
The Crystal and Molecular Structure of Staurosporine, a New Alkaloid from a Streptomyces Strain
Authors: Furusaki Akio , Hashiba Nobuhiro , Matsumoto Takeshi , Hirano Atsushi , Iwai Yuzuru , \={O}mura Satoshi 
Published: July 2006

Abstract
The molecular sturcture of staurosporine, an alkaloid from a Streptomyces strain, has been determined by means of an X-ray crystallographic analysis of its methanol solvate (C28H26N4O3·CH3OH). The crystals are monoclinic, with four formula units in a unit cell with dimensions of a=23.487(6), b=7.636(3), c=15.638(4) Å, and β=116.71(5)°; the space group is C2. 2532 unique intensity data were collected on a four-circle diffractometer with LiF-monochromated Cu Kα radiation. The structure was solved by the Monte Carlo direct method, using the 20 strongest reflections as the starting set; the 72nd random phase set led to the correct solution. The R value reached 0.047 by block-diagonal least-squares refinements. Staurosporine has been found to contain a unique dimeric indole structure. Because of the steric hindrance, the indolo[2,3-a]carbazole aromatic system in the molecule is slightly bent; the two terminal benzene rings make an angle of 7.5° with each other.
Electronic Absorption Spectra and Geometry of Molecular Ions Generated from Stilbene and Related Compounds. II. Radical Ions of (E)-Stilbene and Related Compounds
Authors: Suzuki Hiroshi , Koyano Kinko , Shida Tadamasa , Kira Akira 
Published: July 2006

Abstract
The electronic absorption spectra of radical ions produced by γ-ray irradiation of (E)-stilbene and related compounds in frozen matrices were measured. On illumination and on controlled warming, the spectra of the radical ions of sterically uncrowded stilbenes and diphenylacetylene remained almost unchanged, while those of the radical ions of sterically crowded stilbenes changed noticeably. Examination of the spectra and of their changes led to the following conclusions: (a) The relaxed geometry of the radical ions of sterically uncrowded stilbenes is planar or nearly planar; (b) in the unrelaxed geometries of the radical ions of (E)-α,β-dialkylstilbenes the torsion angles of the Ph–C bonds are nearly as large as in the parent molecules, and on relaxation these angles become smaller and the torsion angle of the central ethylenic bond deviates from 0° to a considerable extent; (c) for the radical ions of ortho-substituted (E)-stilbenes the geometrical change on relaxation is comparatively small.
Catalytic Activity of Planar Copper(II) Complexes for the Chemiluminescence of Luminol
Authors: Oishi Naoyasu , Takeuchi Masataka , Nishida Yuzo , Kida Sigeo 
Published: July 2006

Abstract
Some planar binuclear copper(II) complexes showed high catalytic activity for the chemiluminescence of luminol in the presence of hydrogen peroxide compared with those of mononuclear planar copper(II) complexes. The formation of singlet O2 in the reaction mixture of a binuclear copper(II) complex and hydrogen peroxide was assumed to play a key role in the catalytic function of the binuclear copper(II) complexes for the luminol chemiluminescence.
Metal Complexes of Peptides. III. The Preparation and Properties of Diammine(oligopeptidato)cobalt(III) Complexes
Authors: Kawaguchi Hiroshi , Ishii Mari , Ama Tomoharu , Yasui Takaji 
Published: July 2006

Abstract
Complexes of the [Co(tripeptidato)(NH3)2] and NH4[Co(tetrapeptidato)(NH3)2] types (tripeptidato and tetrapeptidato denote the tri- and tetraanions of the coordinating peptides respectively) have been prepared and characterized by means of their electronic, 1H NMR, and circular dichroism (CD) spectral data. In the NH4[Co(tetrapeptidato) (NH3)2] complex, the pep tide coordinates to cobalt(III) as a quadridentate ligand through the nitrogens of an amino and three amide groups. The additivity of the vicinal CD spectra has been found to hold for the complexes of a series of tripeptides containing l-alanine and/or glycine residue. These tri- and tetrapeptidato complexes in water easily undergo aquation reaction, releasing the ammonia molecule.
An Analysis of the Chemical Compositions of Groundwaters Utilizing a Leaching Technique. An Application to the Rokko Mountains and Their Surroundings
Authors: Tamari Yuzo , Inoue Yukiharu , Tsuji Haruo , Kusaka Yuzuru 
Published: July 2006

Abstract
The chemical composition of groundwaters from granitic alluvial plains is different from that from the clayey “Kobe-group” strata surrounding the Rokko mountains. The former groundwaters are dominantly rich in Ca and HCO3, while the latter are rich in Na and HCO3. In order to investigate the difference in the groundwater compositions, a chemical leaching technique was applied to samples of soils, well-sediments, and rocks collected from the Rokko mountains and their surroundings. Three leaching solutions used were as follows. CO2− saturated water to investigate the effect of chemical weathering; a 0.1 M HNO3 solution to remove hydroxide, sulfide, and colloidal matters; and a 1 M CH3COONH4 solution to leach exchangeable ions from the samples. In the leaching, leachable amounts of Na, K, Ca, and Mg as the major species and Fe and Mn as the minor species in groundwaters were determined. From the results of leaching and adsorption experiments for cations, and from a comparison of the analytical values of the cations in groundwaters with the data of the leaching experiments on the key diagram, the association of the chemical species dissolved in groundwaters with the geological characters was analysed.