Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 56 , Issue 5
Showing 1-50 articles out of 71 articles from the selected issue
  • Masami Tanaka, Keiko Nishikawa, Kazuyuki Tohji, Tsunetake Fujiyama
    1983 Volume 56 Issue 5 Pages 1273-1278
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    A simple method has been proposed for estimating the state of mixing in a binary solution directly from the radial distribution function. The method has been applied to the estimation of the size of the cluster or aggregate in a binary solution of methanol and carbon tetrachloride. Pure liquid carbon tetrachloride and a binary solution of pentane and carbon tetrachloride have also been studied as reference systems. The number of methanol molecules which form a cluster in the solution at the volume ratio of 8.5(CCl4):1.5(CH3OH) has been estimated to be about 18, which is in good agreement with an estimate by light scattering.
  • Akito Kurosaki, Susumu Okazaki
    1983 Volume 56 Issue 5 Pages 1279-1283
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    A mixed oxide of Al and Cr having an atomic ratio(Al/Cr) of around 9 showed catalytic activity for the conversion of CH3OH into olefins and aromatic compounds after treatment with CF3Cl at 450 °C. The mixed oxide treated with CF3Cl adsorbed a considerable amount of NH3, even at temperatures as high as 500 °C. Analyses of the compositions on the surface layer by using XPS showed that the F component was predominantly bound to Al, not to Cr. Strong acid sites related to the less crystallized AlF3 seemed to be able to promote the conversion of CH3OH.
  • Takehiko Ono, Tetsuo Ikehata, Yutaka Kubokawa
    1983 Volume 56 Issue 5 Pages 1284-1288
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    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.
  • Tomoyuki Ohoka, Yoshifumi Kato
    1983 Volume 56 Issue 5 Pages 1289-1300
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The polarized fluorescence spectrum of the europium tris(ethyl sulfate) enneahydrate crystal was measured at 95 K by using excitation lines of an Ar+ laser. The multipole character of transitions and the energies and crystal quantum numbers for the crystal field components of the 7FJ(J=0, 1,···,6) and 5D0.1 terms were determined from the spectral analysis. It was ascertained that most of the transitions were due to forced electric dipole transitions but some of them due to magnetic dipole transitions, in which nine strong lines appeared as magnetic dipole radiations satisfying the selection rule for ion levels, while three weak lines were magnetic dipole radiations forbidden in ions. The relative intensities of both the forbidden electric dipole transitions and the magnetic dipole transitions were calculated by the crystal field wavefunctions obtained to reproduce the experimental data. From the comparison of the calculated intensities with the observed ones, the ratio of the populations of the 5D0 term to the 5D1 term in fluorescent process was estimated to be about 20, although the 5D0 term was 1750 cm−1 lower than the 5D1 term. The result suggested that the configuration mixing due to g-orbitals was significant to allow electric dipole transitions.
  • Tomio Yoshino, Tuneyo Abe
    1983 Volume 56 Issue 5 Pages 1301-1304
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    An experimental investigation was made of the adsorptive activity of Raney nickel catalyst toward potassium iodide over a wide KI concentration range and of the change with KI adsorption of hydrogenating activity toward unsaturated alcohol and ketone. Adsorbed amounts of K+ and I ions were determined by potentiometry and radioactivity measurement. The adsorptive activity vs. I concentration relation yields a definitive break at equilibrium concentration 5.5×105 mol dm−3 (surface coverage 26%), the adsorption features in the lower and higher ranges relative to the break point being approximately represented by Freundlich’s and BET equations, respectively. Adsorption sites effective for I ion in the Freundlich region disappear almost completely when the catalyst is preheated at 600 °C. The surface coverage causing the hydrogenation activity to decrease by 50% is 3% for allyl alcohol and 0.3% for 2-butanone. With allyl alcohol, however, even such a catalyst as has preadsorbed ca. 5-monolayer amount of I ions possesses a 33% residual activity, though catalyst coverages over 26% result in only a little decrease in activity. These results suggest that the adsorption sites in the Freundlich region may function as strong catalytically active centers for the hydrogenation, which are unstable to heating.
  • Tomokazu Matsue, Chikako Tasaki, Masamichi Fujihira, Tetsuo Osa
    1983 Volume 56 Issue 5 Pages 1305-1307
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The effect of α-cyclodextrin (α-CD) on the electroreduction of benzaldehyde was investigated. The reduction in aqueous system produces benzyl alcohol and 1,2-diphenyl-1,2-ethanediol (hydrobenzoin, dimerization product). The addition of α-CD caused the decrease in the yield of hydrobenzoin. This suppression effect was observed both in the controlled potential and controlled current electrolyses. This is accounted for by the retardation of the dimerization rate between the neutral radicals, since inclusion of substrate provides severe steric hindrance around the reaction site. The addition had only a small influence on the stereochemistry of hydrobenzoin formed by the dimerization.
  • Kimihiko Hara, Yoshikazu Katou, Jiro Osugi
    1983 Volume 56 Issue 5 Pages 1308-1313
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Fluorescence spectra of 1,2-di(9-anthryl)ethane (1), 1,3-di(9-anthryl)propane (2), and 9,9′-bianthryl (3) have been studied at high pressures up to 50 kbar both in crystalline state and in PMMA matrix. In the case of 1 and 2 in crystalline state, the excimer emissions appear reversibly at high pressures accompanied by the reversible red shifts. While in PMMA the fluorescence spectra assigned as locally excited state are observed, whose peak shifts are quite analogous to that of anthracene in the same matrix. As for 3, a new band also appears at high pressure which is similar to the intramolecular charge-transfer band. Possible interpretations of the pressure effects are discussed.
  • Yoshinori Hasegawa
    1983 Volume 56 Issue 5 Pages 1314-1318
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The intermediate complex in the aromatic nucleophilic substitution of methyl 4-methoxy-3,5-dinitrobenzoate with piperidine in dimethyl sulfoxide was confirmed by visible absorption spectroscopy. Kinetics of the formation of the intermediate were studied by a stopped-flow spectrophotometer, and rate and equilibrium constants were determined. The observable intermediate (Z) was the conjugate base of the initial zwitterionic complex (ZH). Proton transfer between ZH and Z was rate limiting and the intermediate formation was base catalyzed.
  • Hiroyuki Kageyama, Kunio Miki, Nobuo Tanaka, Nobutami Kasai, Yoshio Ok ...
    1983 Volume 56 Issue 5 Pages 1319-1321
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The molecular structure of EtMgBr-(−)-sparteine, which initiates asymmetric (enantiomer) selective polymerization of racemic methacrylates, has been determined by means of X-ray diffraction. The crystal is orthorhombic, space group P212121, a=11.278(2), b=14.112(3), c=11.746(2) Å, Z=4. The structure was established by the heavy atom method and refined by the block-diagonal least-squares procedure: R=0.100 for 1272 non-zero reflections. The Mg atom is tetrahedrally coordinated by the Et group, Br and two N atoms of the (−)-sparteine.
  • Takashi Kakiuchi, Mitsugi Senda
    1983 Volume 56 Issue 5 Pages 1322-1326
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    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.
  • Yoshimi Ishibashi, Fumiko Arakawa, Hiroko Shimada, Ryoichi Shimada
    1983 Volume 56 Issue 5 Pages 1327-1336
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    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.
  • Masahide Shimokawabe, Nobutsune Takezawa, Haruo Kobayashi
    1983 Volume 56 Issue 5 Pages 1337-1340
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Temperature programmed reduction (TPR) has been used to study copper–silica catalysts which were prepared by ion exchange method and the effects of preparation of catalysts upon their reducibilities were elucidated. Three peaks appeared with maxima at 265–300 °C (α), 400 °C (β), and 650–800 °C (γ) over the catalysts calcined at 500 °C. Highly dispersed cupric oxide clusters were reduced to metallic copper, giving α peak. Isolated copper(II) ions which were strongly interacted with silica surface were reduced stepwise to metallic copper through copper(I) ion species, giving α and γ peaks. However, isolated copper(II) ions which were weakly interacted with the support gave α and β peaks. When the catalysts were precalcined above 800 °C, the fourth peak (α′) appeared at 330–350 °C and α, β, and γ peaks diminished. This was assigned to the reduction of bulk CuO which was crystallized from species described above. The reducibility of copper–silica catalyst was found to depend strongly upon the conditions of preparation.
  • Syoichi Makimoto, Keizo Suzuki, Yoshihiro Taniguchi
    1983 Volume 56 Issue 5 Pages 1341-1345
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    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*.
  • Kozue Kaibara, Hideaki Sonoda, Yoshihiko Nagata, Hideo Kimizuka
    1983 Volume 56 Issue 5 Pages 1346-1350
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Transport characteristics of NH4Cl, (CH3)4NCl (TMA–Cl), (C2H5)4NCl (TEA–Cl), (n-C3H7)4NCl (TPA–Cl), and (n-C4H9)4NCl (TBA–Cl) across homogeneous type amphoteric ion exchange membrane (1.0-PA-29, Kanegafuchi Chem. Ind.) were studied. Membrane potentials and conductances of the concentration cell systems were measured to calculate the membrane permeabilities which represent a measure of ionic permselectivity. Membrane potential changed considerably with cationic species and the membrane tended to behave more anionic selectively with increasing bulkiness of cations. The cationic permeabilities calculated from electrochemical data were PNH4>PTMA>PTEA>PTPA>PTBA. Membrane permeabilities to chloride ions, PCl, were greater than those to cations in all the systems studied and it was interesting that PCl values and their dependencies on external electrolyte concentration were almost unchanged irrespective of the difference in cationic species. The present experiment was designed in order to examine the effects of ionic size on the transport processes across homogeneous type amphoteric ion exchange membrane. The obtained results indicated that the hydrated radius of permeant ion is an important factor to control the ionic transport processes and to reveal the potentiometric selectivity in these systems. It was suggested that the ion transport across homogeneous type amphoteric ion exchange membrane is strongly affected by hydrodynamic properties of permeant ion, but scarcely influenced by ionic charges of which effects are well known to be exclusive in the uniform cation and anion exchange membranes.
  • Hiroshi Maeda, Takaaki Kishi, Shoichi Ikeda
    1983 Volume 56 Issue 5 Pages 1351-1356
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The precipitation of human fibrinogen by ZnCl2 was studied by measuring the turbidity and the protein concentration in the supernatant (referred as solubility). Different kinetic patterns, either fast or slow, were observed in both solubility and turbidity depending on whether ZnCl2 concentration (CM) was larger or smaller than the critical concentration. In the slow pattern, the increase of the turbidity and the decrease of the solubility both occurred slowly and almost linearly with time. In the fast pattern, these changes occurred rapidly and stationary values were reached within 30 min for the turbidity and 2 h for the solubility. These two stationary values were found to be linearly related to each other. The stationary solubility decreased as CM increased, while it increased with the total amount of the protein. The dissolution of the precipitates was very slow resulting in a practically irreversible precipitation. A gelation model was proposed to account for these characteristic features, according to which fibrinogen molecules were linked to each other through the ’bond’ mediated by a zinc atom.
  • Takaaki Kishi, Hiroshi Maeda, Shoichi Ikeda
    1983 Volume 56 Issue 5 Pages 1357-1361
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Kinetics of the precipitation of human fibrinogen by the addition of ZnCl2 was followed by the turbidity at 350 or 500 nm. Fast or slow precipitation occurred depending on whether the metal concentration (CM) was higher or lower than its critical value. In fast precipitations, the turbidity reached the stationary value within about 30 min. From the stationary values of the turbidity the critical concentration could be determined. A sigmoidal increase of the turbidity was often observed at low protein concentrations (CP); the lag time decreased with both CM and CP. At the final stage of the precipitation, the turbidity reached the stationary value exponentially; the characteristic time constant was almost independent of both CM and CP. These kinetic behaviors were consistent with the gelation model proposed to the present precipitation. When CuCl2 was used in place of ZnCl2, similar kinetic behaviors were obtained in many respects, suggesting the similar mechanism of precipitation for both ZnCl2 and CuCl2. Changes from slow to fast precipitation were observed when ionic strength was lowered.
  • Yoshimi Ishibashi, Ryoichi Shimada, Hiroko Shimada
    1983 Volume 56 Issue 5 Pages 1362-1367
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The polarized Raman and infrared spectra of dichloromaleic anhydride were studied and the assignments of the normal vibrations were reinvestigated based on the polarization behaviors of the spectral bands and on the normal coordinate calculation. Using the assignments the vibrational structure of the phosphorescence spectrum was analyzed and the phosphorescence lifetime was also measured. These results indicate that the lowest triplet state of this molecule is a 3(π, π*) state perturbed by closely located 3(n, π*) states. The near ultraviolet absorption and phosphorescence excitation spectra were measured and four absorption bands due to 3(n, π*)←1A1, 1A2(n, π*)←1A1, 1B1(n, π*)←1A1, and 1A1(π, π*)←1A1 transitions were found. The polarization experiment made on the 1A2(n, π*)←1A1 absorption suggests that this transition borrows the intensity from the 1A1(π, π*)←1A1 transition.
  • Isao Ando, Kiyomi Yoshizumi, Kazuhisa Ito, Kikujiro Ujimoto, Hirondo K ...
    1983 Volume 56 Issue 5 Pages 1368-1371
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The mono-complex formation of 2-thenoyltrifluoroacetone (HTTA) with nickel(II) and copper(II) ions was studied in aqueous solution at 25.0 °C and an ionic strength of 0.20 mol dm−3 by means of a stopped-flow method. The rate-[H+] profiles for the formation of these mono-complexes revealed that the rate-determining step of the complex formation interchanges depending upon hydrogen-ion concentration, as in the case of the Ni(II)–bpy complex. The rate constants of the mono-complex formation with TTA, kf, and that with HTTA, kfh, were determined from the rate-[H+] profile in the region of the high hydrogen-ion concentration, where the pseudo-equilibrium of acid dissociation of the ligand was maintained during the complex formation; kf=(9.2±3.0)×102, kfh=(1.3±0.3)×10−1 mol−1 dm3 s−1 for the Ni(II)–TTA complex and kf=(2.0±1.2)×103, kfh=(5.0±0.9)×10−1 mol−1 dm3 s−1 for the Cu(II)–TTA complex. The deprotonation-rate constants of HTTA could be evaluated from the apparent rate constants of the complex formation in low hydrogen-ion concentration. The values thus obtained agreed well with that determined independently by a pH jump method.
  • Mitsutomo Tsuhako, Akiko Nakahama, Shigeru Ohashi, Hiroyuki Nariai, It ...
    1983 Volume 56 Issue 5 Pages 1372-1377
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The reaction of sodium cyclo-triphosphate (P3m) with ethylenediamine (en) was studied with special attention paid to the kinds and amounts of products under various conditions and to its reaction mechanism. 1) The reaction of P3m with ethylenediamine in the pH range of 8–12 gave six new compounds; three of them were identified as N,N-bis(2-aminoethyl)phosphorodiamidate (P1-en2), N-(2-aminoethyl)amidodiphosphate (P2-en), and N-(2-aminoethyl)-P-amidotriphosphate (P3-en). 2) The formation of P3-en and P2-en was most favored at a pH near 10(about 32 and 9% respectively), while that of P1-en2 proceeded extensively at pH 10–12(about 12%). 3) The amounts of products varied greatly depending on the mixing ratio of P3m and ethylenediamine. P1-en2 was the predominant product at en/P3m>1, while P3-en was at en/P3m≤1. 4) At a pH value below 10, tetra(P4) and pentaphosphate (P5) were formed in addition to the above products. The reaction between P3m and ethylenediamine scarcely proceeded under acidic conditions. 5) Ortho-(P1), pyro-(P2), and triphosphate (P3) did not react with ethylenediamine at all. 6) The reaction mechanism between P3m and ethylenediamine was discussed.
  • Tadashi Hara, Fujio Okui
    1983 Volume 56 Issue 5 Pages 1378-1381
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The absolute content of C, H, O, and N in an organic compund including a metal organic chelate was satisfactorily determined on the basis of pyrolytic sulfurization gas chromatography. A 1.0–1.3 mg sample was weighed on a microbalance, and was subjected to pyrolytic sulfurization. The gases evolved by the reaction were estimated by gas-chromatography. By using both the analytical result of each product and its calibration factor previously obtained by analyzing cyanoguanidine, 8-quinolinol, and sucrose as standard samples, the absolute content of C, H, O, and N was calculated satisfactorily for each substance.
  • Tadashi Hara, Motohiro Toriyama, Kazuhiko Tsukagoshi
    1983 Volume 56 Issue 5 Pages 1382-1387
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    A new method in which luminol-hydrogen peroxide luminescent system is used has been proposed for the determination of the presence of protein. Since the catalytic activity of copper(II) for the chemiluminescent reaction between luminol and hydrogen peroxide decreased when copper(II) interacted with polypeptide linkage, this phenomenon was applied to the determination of protein. Determination of protein was carried out by a flow-injection method. The effects of reagent concentration, flow-rate, and reaction time on the analytical value were examined and the conditions for the determination of protein were established. Similar calibration curves were obtained for human serum albumin, bovine serum albumin, bovine serum α-globulin, and bovine serum γ-globulin. According to the present flow-injection method using chemiluminescent reaction, a small amount of protein could be conveniently and economically determined over a wide range of concentration, 7×10−4–7×10−2 g dm−3, with the detection limit of 0.2 μg and at the rate of about 30 samples per hour. The present method was applicable to the determination of protein in serum.
  • Naohide Matsumoto, Toshihiro Tsutsumi, Akira Ohyoshi, Hisashi Okawa
    1983 Volume 56 Issue 5 Pages 1388-1392
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Alkoxo-bridged polynuclear copper(II) complexes with condensation products of 3-ethoxymethylene-2,4-pentanedione and each of three amino alcohols, 2-aminoethanol, 3-amino-1-propanol, and 1-amino-2-propanol, were prepared and characterized by elemental analyses, infrared spectra, electronic spectra, molecular weight measurements, magnetic susceptibility measurements, and crystal structure analysis, the complexes being abbreviated as Cu(L-2), Cu(L-3), and Cu(L-2m), respectively. Cu(L-3) is a dimer, but Cu(L-2m) and Cu(L-2) are tetramers. The magnetic susceptibility of violet Cu(L-3), whose electronic spectrum exhibits a d-d band maximum at 17.7×103 cm−1, is in conformity to the Bleaney-Bowers equation with exchange integral −2J=920 cm−1. Cu(L-3) consists of alkoxo-bridged centrosymmetric binuclear units, where the geometries around the copper ion and bridged oxygen atom are planar and the angle of Cu–O–Cu is 103.6(1)°. The magnetisms of blue complexes Cu(L-2) and Cu(L-2m) exhibiting a d-d band maximum at 15.7×103 cm−1 obey the Curie Weiss law with positive Weiss constants 17 and 20 K, respectively, and are in accord with the Heisenberg model based on a tetranuclear cubane-like structure.
  • Kurumi Yamada, Shigeru Baba, Yukio Nakamura, Shinichi Kawaguchi
    1983 Volume 56 Issue 5 Pages 1393-1400
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Novel palladium(II) complexes [Pd(β-dik)(η3-etac)] (5), in which anions of a β-diketone and ethyl 3-oxobutanoate coordinate to the central metal atom by the O,O′-chelation and the η3 carbon bonding, respectively, were prepared by the reactions of a dinuclear complex [PdCl(η3-etac)]2 with thallium (I) β-diketonates in benzene or acetone at room temperature. Reactions of 5 with Lewis bases (L) such as triphenylphosphine, diethylamine, propylamine and benzylamine were investigated. In almost all reactions, only the η3-carbon-bonded ester ligand in 5 was converted into a terminal-carbon-bonded one to afford complexes [Pd(β-dik)(etac-C4)L]. The bonding modes for the ligands in these products as well as in 5 were determined by means of IR and 1H and 13C NMR spectroscopy.
  • Hiromichi Yamada, Shozo Imai, Eiichi Takeuchi
    1983 Volume 56 Issue 5 Pages 1401-1406
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Extraction of gallium(III) with decanoic acid (HA) in several solvents was carried out at 25 °C and at an aqueous ionic strength of 0.1 mol/dm3(NaClO4). Organic solvents used are toluene, chlorobenzene, 1,2-dichloroethane, and 1-octanol. Extracted species differs from solvent to solvent: Ga6A18(H2O)w for toluene, Ga3A9 for chlorobenzene, GaA3 and Ga3A9 for 1,2-dichloroethane and GaA2(OH), Ga2A4(OH)2 and Ga2A6 for 1-octanol. The less polar the solvent, the more extensive is the polymerization of the extracted species.
  • Ushio Sakaguchi, Ippei Yamamoto, Shinji Izumoto, Hayami Yoneda
    1983 Volume 56 Issue 5 Pages 1407-1409
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The retention volumes of enantiomers of several complex anions on the IEX 220 anion-exchange resin, when eluted by an aqueous solution of Δ-[Co(en)3]3+, Δ-[Co(sep)]3+, or Δ-[Co(l-chxn)3]3+, have been measured as a function of the eluent concentration, where en=ethylenediamine, sep=1,3,6,8,10,13,16,19-octaazabicyclo[6.6.6]eicosane, and l-chxn=(−)-trans-1,2-cyclohexanediamine. The order of retention volumes of enantiomers of some complex anions has been found to be inverted by the concentration of the eluents. The mechanism of the inversion has been discussed.
  • Katsuma Hiraki, Masayoshi Onishi, Minoru Hayashida, Kyogo Kurita
    1983 Volume 56 Issue 5 Pages 1410-1413
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    A Schiff base, 4-[2-(methylthio)anilino]-3-penten-2-one (Hmtap), prepared from acetylacetone and 2-(methylthio)aniline, reacted with Na2[PdCl4] in the presence of sodium ethoxide to give [PdCl(mtap-O,N,S)] (1). Complex 1 was treated with carbanions formed from dimethyl malonate, methyl cyanoacetate, and malononitrile in the presence of sodium methoxide to afford the corresponding (disubstituted methyl)palladium(II) complexes, [Pd(CHYY′)(mtap-O,N,S)] (Y,Y′=COOMe and/or CN). On the other hand, 1 reacted with Tl(acac) to yield an O,O′-chelating complex, [Pd(mtap-N,O)(acac)], in which the mtap moiety served as a bidentate ligand. Moreover, 1 reacted with 2,2′-bipyridine (bpy) and 4-(dimethylamino)pyridine (dmapy) in the presence of NaClO4·H2O to give [Pd(mtap-N,O)(bpy)]ClO4 and [Pd(mtap-O,N,S)(dmapy)]ClO4, respectively. These complexes are characterized by means of elemental analysis and IR and NMR spectroscopy.
  • Akira Tai, Tadao Harada, Yuji Hiraki, Sigeki Murakami
    1983 Volume 56 Issue 5 Pages 1414-1419
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The mode of enantioface-differentiating hydrogenation with asymmetrically modified Raney nickel (MRNi) was investigated by using various sorts of modifying reagents and substrates. The optical yields (O.Y.) of the hydrogenation of methyl acetoacetate over MRNi for different modifying reagents occured in the following order: (Remark: Graphics omitted.), (Remark: Graphics omitted.). The hydrogenation of various substrates of the structure, (Remark: Graphics omitted.), over tartaric acid-modified Raney nickel (TA–MRNi), gave high optical yields only when the substituent –Y functioned as a good hydrogen bond acceptor like a carbonyl group, and two pairs of hydrogen bondings between substrate and two hydroxyl groups of tartaric acid were available. As for the stereochemistry of the reaction in such a case, (R,R)-TA–MRNi always gave (R)-product in excess. Based on the stereochemistry of the reaction and the role of hydrogen bonds between modifying reagent and substrate, a stereochemical model is proposed to elucidate the mode of enantioface-differentiating hydrogenation of prochiral ketones over TA–MRNi.
  • Masaru Tada, Kunimi Inoue, Masami Okabe
    1983 Volume 56 Issue 5 Pages 1420-1423
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The photolysis of 2-aryl-2-ethoxy-2-phenylethyl cobaloxime followed by hydrolysis gave two kinds of substituted 1,2-diphenylethanones arising via phenyl or substituted-phenyl migration. The substituent effect on the aryl rearrangement is similar to that on the reported neophyl rearrangement, and the rearrangement takes place by a radical mechanism without the deep involvement of cobaloxime(II).
  • Hiroshi Takaku, Souichi Ueda
    1983 Volume 56 Issue 5 Pages 1424-1427
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    N6,3′-O-Dibenzoyladenosine was prepared by treating 2′,3′-O-(dibutylstannylene)-N6-benzoyladenosine with benzoyl chloride in methanol. The trimeric adenylyl-(2′–5′)-adenylyl-(2′–5′)-adenosine was synthesized in a good yield using N6,3′-O-dibenzoyladenosine as the starting material via the phosphotriester approach.
  • Yoshihisa Watanabe, Yasushi Tsuji, Ryo Takeuchi
    1983 Volume 56 Issue 5 Pages 1428-1430
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    1,3-Dioxolane reacted with electron-deficient alkenes, such as diethyl maleate, maleic anhydride, diethyl fumarate and fumaronitrile, under an oxygen atmosphere or in air to give 1:1 adducts in good to excellent yields. The presence of oxygen promoted the reaction. The reaction appears to be characteristic of 1,3-dioxolane. Methylal and ethylal did not react with diethyl maleate under the same conditions.
  • Tetsuo Suami, Katsumi Nakamura, Tamio Hara
    1983 Volume 56 Issue 5 Pages 1431-1434
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Trioxacarcinose B is a unique carbohydrate which has been discovered in antibiotic trioxacarcin A as a component. As a step of total synthesis of the antibiotic, methyl α-trioxacarcinoside B has been synthesized from methyl 2,3-anhydro-6-deoxy-α-L-allo-hexopyranoside by a 7 steps reaction in a yield of 4.3%. The product has been identified by comparison with the authentic sample which was prepared by methanolysis of the antibiotic.
  • Katsumi Nakamura, Tomoyuki Asai, Tamio Hara, Naoki Minorikawa, Tetsuo ...
    1983 Volume 56 Issue 5 Pages 1435-1440
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Seven 1-O-glycosyl derivatives of 4-[2-(2-hydroxyethylamino)ethylamino]-9,10-anthracenedione have been prepared as potential antineoplastic agents.
  • Seiichiro Ogawa, Masayuki Oya, Tatsushi Toyokuni, Noritaka Chida, Tets ...
    1983 Volume 56 Issue 5 Pages 1441-1445
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    DL-1-Epivalidamine has been synthesized starting from the dianhydro compound derived from DL-1,2,3-tri-O-acetyl-(1,3/2,4,6)-4-bromo-6-bromomethyl-1,2,3-cyclohexanetriol. DL-7-Amino-7- deoxy-1-epivalidamine, which is considered to be a homolog of 2-deoxystreptamine, has also been prepared.
  • Shuki Araki, Yasuo Butsugan
    1983 Volume 56 Issue 5 Pages 1446-1449
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Coupling reactions of 3-furylmethylmagnesium bromide with prenyl and geranyl diethyl phosphates gave 2-substituted 3-methylfurans, rosefuran and sesquirosefuran, as the main products. When the reactions were carried out in the presence of a catalytic amount of copper(I) iodide, normal coupling occurred and 3-substituted furans, perillene and dendrolasin, were formed in good yields. The related naturally occurring 3-substituted thiophene, 3-(4-methyl-3-pentenyl)thiophene, was also synthesized from 3-thienylmethylmagnesium bromide and prenyl diethy phosphate.
  • Masao Tada, Hisaaki Saeki, Atsushi Oikawa
    1983 Volume 56 Issue 5 Pages 1450-1554
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The compounds, 3-amino-9H-pyrido[3,4-b]indole and 3-amino-1-methyl-9H-pyrido[3,4-b]indole, which are effectors in induction of sister chromatid exchanges in human cells, were isolated from pyrolysis products of L-tryptophan and characterized by HPLC and UV techniques.
  • Sadatoshi Akabori, Michiko Ohtomi, Masaru Sato, Seiji Ebine
    1983 Volume 56 Issue 5 Pages 1455-1458
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Acyclic polyethers (7) (containing a ferrocene nucleus in both terminal sites) were synthesized by a one-pot reaction of 1,1′-diacetoxyferrocene with halide. Also, ferrocene derivatives (11) having polyethylene glycols were synthesized by the reaction of potassium salt of hydroxyferrocene with dihalide in DMF. On the addition of alkali metal thiocyanate in methanol, a hypsochromic shift and an increasing intensity of the absorption band at 438 nm were observed in ferrocene-containing polyethers 7, suggesting the complexing of 7 with cations. However, a similar spectral change could not be observed in 11. 7a extracts silver and thallium ions most effectively, the extraction efficiency of several metal cations being in this order: Ag+>Tl+>Cs+>K+>Li+>Na+.
  • Sadatoshi Akabori, Yoichi Habata, Masaru Sato, Seiji Ebine
    1983 Volume 56 Issue 5 Pages 1459-1461
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Mononuclear polyoxathia[n]ferrocenophanes (8ad) and binuclear polyoxadithia[n,n]ferrocenophanes were synthesized by the reaction of 1,1′-bis(ω-chloropolyethyleneoxy)ferrocene with sodium sulfide in N,N-dimethylformamide and the complexing ability of 8ad with alkali and transition metal cations was measured by an extraction method. Compound 8d extracts a thallium ion specifically, the extraction efficiency of several ions being in the order: Tl+>>Rb+>K+>Cs+>Na+>Li+.
  • Toshihiro Seo, Kenji Abe, Toshio Kakurai
    1983 Volume 56 Issue 5 Pages 1462-1466
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The reaction of 2-amino-4-(substituted amino)-6-isopropenyl-1,3,5-triazines (methacryloguanamine) with formaldehyde gave several new monomers having hydroxymethyl groups in satisfactory yields. These monomers were easily converted into the corresponding alkyl ethers with methanol. Their melting points and solubilities were affected considerably by the species and the number of substituted groups. Especially, tetrakis(hydroxymethyl)methacryloguanamine and its methoxymethyl derivative were readily soluble in water and nonpolar solvents, respectively. The former was polymerized and crosslinked smoothly to yield a insoluble polymer. Copolymerization of the latter with methyl methacrylate, however, gave soluble polymers, formed flexible and tough films. Similarly, the reactive polymers were prepared from polymers containing guanamine structure by hydroxymethylation followed by etherification.
  • J\={u}ro Ojima, Mitsuru Kirita, Yoshiko Murosawa, Tetsuya Nakada
    1983 Volume 56 Issue 5 Pages 1467-1475
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The conjugated mono-, di-, tri-, and tetraene, containing a terminal acetylene group were converted into a variety of symmetrical and unsymmetrical conjugated azines on treatment with aqueous hydrazine in ethanol. Oxidative couplings of these azines were attempted using anhydrous copper(II) acetate in pyridine and ether. Each of unsymmetrical azines, 3,16-dimethyl-8,9-diaza-3,5,7,9,11,13,15-octadecaheptaene-1,17-diyne and 1,10-bis(o-ethynylphenyl)-4,5-diaza-1,3,5,7,9-decapentaene, gave the corresponding two isomeric cyclic dimers: The former gave 7,12,25,30-tetramethyl-8,10,26,28-tetrakisdehydro-1,2,17,18-tetraaza[36]annulene and 7,12,25,30-tetramethyl-8,10,26,28-tetrakisdehydro-1,2,19,20-tetraaza[36]annulene, and the latter gave 6,7:12,13:24,25:30,31-tetrabenzo-8,10,26,28-tetrakisdehydro-1,2,17,18-tetraaza[36]annulene and 6,7:12,13:24,25:30,31-tetrabenzo-8,10,26,28-tetrakisdehydro-1,2,19,20-tetraaza[36]annulene, although only in poor yields. Coupling of symmetrical azines, 3,22-dimethyl-12,13-diaza-3,5,7,9,11,13,15,17,19,21-tetraeicosadecaene-1,23-diyne and 1,16-bis(o-ethynylphenyl)-8,9-diaza-1,3,5,7,9,11,13,15-hexadecaoctaene, furnished cyclic dimers, 11,16,35,40-tetramethyl-12,14,36,38-tetrakisdehydro-1,2,25,26-tetraaza[48]annulene and 10,11:16,17:34,35:40,41-tetrabenzo-12,14,36,38-tetrakisdehydro-1,2,25,26-tetraaza[48]annulene, respectively, in moderate yields. Examination of 1H NMR spectra indicates that these tetraazaannulenes are atropic.
  • Yozo Miura, Akifumi Yamamoto, Masayoshi Kinoshita
    1983 Volume 56 Issue 5 Pages 1476-1481
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The reactions of N-(4-chlorophenylthio)-3,5-di-t-butylphenylaminyl (1) with phenols were examined. The reaction with 2,6-dimethyl- and di-t-butylphenols gave 2,6-dimethyl- and di-t-butyl-p-benzoquinone 3,5-di-t-butylphenylimines, respectively, in excellent yields. In the reaction with unsubstituted phenol, 2,6-bis[N-(4-chlorophenylthio)-3,5-di-t-butylphenylamino]-p-benzoquinone 3,5-di-t-butylphenylimine was obtained in 32–56% yields. On the other hand, the reactions with p-substituted phenols such as p-cresol, p-t-butylphenol, and 2,4-di-t-butylphenol, gave phenols which were substituted by 1 at the ortho-positions to the OH group. Furthermore, the reactions with o-cresol, 2,6-di-t-butyl-p-cresol, and 1-naphthol were examined. On the basis of these results, plausible mechanisms for the reactions are presented.
  • Hisao Nishi, Yuichi Hatada, Kiyoshi Kitahara
    1983 Volume 56 Issue 5 Pages 1482-1486
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    A new class of 6,13-bis(arylamino)triphenodithiazines has been synthesized by condensing chloranil with arylamines followed by the reaction of the resulting 2,5-bis(arylamino)-3,6-dichloro-1,4-benzoquinones with zinc 2-aminobenzenthiolates (4) in the presence of a base in Methyl Cellosolve. On the other hand, the reaction of 2,5-dianilino-3,6-dichloro-1,4-benzoquinone (3a) with 4 in DMF proceeded unexpectedly to give 7,14-dihydro-6,13-triphenodithiazinequinones by eliminating the anilino groups of 3a.
  • Hiroko Suezawa (née Endo), Minoru Hirota, Michiharu Sugiura, Yo ...
    1983 Volume 56 Issue 5 Pages 1487-1489
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Conformational preference and rotational barriers of 1′,1′,2,2-tetrachloro-3′-formyl-1′a,7′b-dihydrospiro[cyclopropane-1,2′(3′H)-cyclopropa[c]quinolines] (1) and related N-formyl heterocyclic compounds were determined by 1H- and 13C-NMR spectroscopy. The sp-conformer is usually more preferable in 1 and their rotational barriers about amide C–N bond are within a relatively narrow range from 70.7 to 72.8 kJ mol−1. Infrared carbonyl absorptions of these compounds also support the preferred conformation from the NMR data. The results were discussed from the view point of N–C=O conjugation.
  • Yasuji Izawa, Katsuhiro Ishiguro, Hideo Tomioka
    1983 Volume 56 Issue 5 Pages 1490-1496
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Irradiation of p-substituted α,α,α-tribromoacetophenones (1) in O2-saturated alcohols (MeOH, prim. and sec. alcohols) afforded a new alcoholysis product, benzoylformate (2), in good yield (75–85%) along with benzoate and radical (reduction) products. Sensitization experiments showed that 2 was derived from the triplet excited 1. Formation of 2 as well as the decomposition rate of 1 were greatly accelerated by oxygen, presumably as a result of the involvement of the normally forbidden S0→T1 transition of 1 due to the oxygen-1 charge transfer complex. Independent synthesis and reaction of possible intermediates in the photoalcoholysis of 1 leading to 2 suggested that 2 was formed from spontaneous (dark) reactions of initial photoalcoholysis product, α,α-dibromo-α-alkoxyacetophenone.
  • Takakazu Yamamoto, Ken-ichi Sanechika, Akio Yamamoto
    1983 Volume 56 Issue 5 Pages 1497-1502
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Nickel compounds (NiCl2 and NiCl2(2,2′-bipyridine)) catalyze polycondensation of dihalothiophenes (2,5-dihalothiophenes, 2,4-dibromothiophene, and 3-methyl-2,5-dibromothiophene) by dehalogenation with magnesium to give the corresponding poly(thienylene) type polymers (poly(2,5-thienylene), poly(2,4-thienylene), and poly(3-methyl-2,5-thienylene)). Copolymerization of 2,5-dibromothiophene and 2,4-dibromothiophene affords copolymers formulated as (\llap–2,5-C4H2S) \llap–m(\llap–2,4-C4H2S) \llap–n. About 15 wt% of poly(2,5-thienylene) prepared in THF at 66 °C is soluble in CHCl3 at room temperature and the CHCl3-soluble fraction has a molecular weight of 1370. The remaining fraction is considered to have a higher molecular weight as judged from its physical properties. IR and 1H-NMR spectra of the polymers are consistent with the structures described above. The electronic spectra of poly(2,5-thienylene) and poly(3-methyl-2,5-thienylene) show large bathochromic shifts of the π-π* absorption bands from those of thiophene and 3-methylthiophene, respectively, indicating that π-electrons in these polymers are extensively delocalized along the polymer chains. In contrast to the electronic spectra of these polymers, that of poly(2,4-thienylene) shows only a minor shift of the π-π* absorption band from that of thiophene reflecting the less extensive π-electron delocalization along the polymer chain in the poly(2,4-thienylene). All the polymers are nonsensitive to air and have high thermal stabilities.
  • Takakazu Yamamoto, Ken-ichi Sanechika, Akio Yamamoto
    1983 Volume 56 Issue 5 Pages 1503-1507
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    Affinities of poly(thienylene) type polymers toward electron acceptors (iodine and SO3) and electric conductivities of the polymer–electron acceptor adducts have been investigated. π-Conjugated poly(2,5-thienylene) has a high affinity toward iodine to absorb 60 wt% of iodine per the polymer. Poly(3-methyl-2,5-thienylene) has a higher affinity toward iodine and absorbs 136 wt% of iodine per the polymer. In the case of copolymer composed of 2,5- and 2,4-thienylene units the affinity against iodine increases with increase in the proportion of the 2,5-thienylene unit in the copolymer. The poly(2,5-thienylene)–iodine and poly(3-methyl-2,5-thienylene)–iodine adducts show electric conductivities of 5×10−2 S cm−1 and 4×10−1 S cm−1, respectively, at room temperature. The activation energies of the electric conduction are 10 kJ/mol and 7.6 kJ/mol for the poly(2,5-thienylene)–iodine adduct (wt% of iodine=60) and poly(3-methyl-2,5-thienylene)–iodine adduct (wt% of iodine=136), respectively. The electric conductivity of the copolymer–iodine adduct sharply decreases on introduction of the 2,4-thienylene unit into the copolymer. The electric conductivity of the iodine adduct of the copolymer containing only 6% of 2,4-thienylene unit drops to ca. 1/100 of that of the iodine adduct of pure poly(2,5-thienylene). The activation energy of the electric conduction of the polymer-iodine adducts decreases with increase in the content of the 2,5-thienylene unit as well as with the increase in the amount of iodine absorbed. Every poly(thienylene) type polymer has a high affinity toward SO3, a stronger electron acceptor than iodine, to absorb about 70 wt% of SO3 per the polymer. The SO3–polymer adducts have electric conductivities of ca. 10−4 S cm−1.
  • Yoshio Ohara, Kin-ya Akiba, Naoki Inamoto
    1983 Volume 56 Issue 5 Pages 1508-1513
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    N,N-Dimethyl-2-(alkylthio)ethylamines and 3-methylthiazolidines underwent N-methylation both with trimethyloxonium tetrafluoroborate (3a) and with methyl iodide. In the methylation of N,N-dimethyl-o-(methylthio)aniline, the main reaction was S-methylation. On the other hand, in the o-ethylthio derivative, S-methylated product was major with methyl iodide, while N-methylated product was major with 3a. In the N-ethyl or N-benzyl derivative, only S-methylation occurred with both reagents. 3-Methyl-2, 2-diphenyl-2,3-dihydro-benzothiazole gave S-methylated product with 3a, suggesting that S-methylation becomes major when the 2-substituent is bulkier. 4-Methyl-3,4-dmydro-2H-benzo[b][1,4]thiazine was methylated on the nitrogen with 3a, while it gave S-methylated product with methyl iodide. Phenothiazines and 1-dialkylamino-8-(methylthio)naphthalenes gave only S-methylated products. The selective S-methylation in the case of N-methylation was carried out through protonation on the nitrogen atom followed by methylation with 3a. Possibility of intramolecular interaction between sulfonio and amino groups has been discussed based on their NMR data.
  • Shinsaku Shiraishi, Tohru Hayakawa, Tadashi Shigemoto
    1983 Volume 56 Issue 5 Pages 1514-1518
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    The reactions of nitrile oxides with S,S-dimethyl-N-(2,4,6-trihalophenyl)sulfimides gave unusual products, which structure was determined to be 2-aryl-4,6-dihalobenzoxazoles from their elementary analyses and spectral data. While the reactions with S,S-dimethyl-N-(2-bromophenyl)- or S,S-dimethyl-N-(2,4-dibromophenyl)sulfimide gave 1,2,4-benzoxadiazine derivatives. A plausible reaction mechanism for the unusual formation of benzoxazoles was proposed.
  • Nobutaka Suzuki, Yoshihiko Kazui, Toshio Tsukamoto, Masahiro Kato, Yas ...
    1983 Volume 56 Issue 5 Pages 1519-1521
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    10-Methylacridinium methyl sulfate and the 1-methylquinolinium salt gave strong light emission, when oxidized with ground state oxygen in the presence of t-BuOK in DMSO, owing to the fluorescence of 10-methyl-9(10H)-acridinone and 1-methyl-1(4H)-quinolinone excited to their S1 state.
  • Takahiro Torii, Tsutomu Tsuchiya, Sumio Umezawa, Hamao Umezawa
    1983 Volume 56 Issue 5 Pages 1522-1526
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    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.
  • Kazuki Sato, Masao Kawai, Ukon Nagai
    1983 Volume 56 Issue 5 Pages 1527-1531
    Published: 1983
    Released: June 27, 2006
    JOURNALS FREE ACCESS
    N-(2,4-Dinitrophenyl)tetrapeptide p-nitroanilides related to the β-turn part of gramicidin S were synthesized and subjected to CD measurements. The β-turn preference of the tetrapeptide derivatives had correlation with the antibiotic activities of the gramicidin S analogs containing similar tetrapeptide sequences at their β-turn part. So, conformational preference of partial sequences of gramicidin S analogs seem to play a significant role for determining their biological activities.
feedback
Top