bluuebunny/crossref_metadata_2025 huggingface dataset:
Ylide–Metal Complexes. XIII. An X-Ray Photoelectron Spectroscopic Study of Bis(dimethylsulfoxonium methylide)gold Chloride
Authors: Konno Hidetaka , Yamamoto Yoshihisa
Published: July 2006

Bis(dimethylsulfoxonium methylide)gold chloride, [(CH3)2S(O)CH2AuCH2S(O)(CH3)2]Cl, has been studied by X-ray photoelectron spectroscopy. The C 1s spectrum was separated into two peaks at EB=284.0 and 285.1 eV in a ratio of 1:2. The peak at 285.1 eV corresponds to the methyl carbons, and that at 284.0 eV is assigned to the electron-rich methylene carbon (or carbanion). The EB of Cl 2p3⁄2 agreed with that for chlorobis(triphenylphosphine)gold(I) and chlorobis(triphenylmethylenephosphorane)gold(I). The EB of Au 4f7⁄2 was 84.4 eV, suggesting the oxidation number +1. These results indicate that the structure of the title complex is (CH3)2S(O)CH2Au(Cl)CH2S(O)(CH3)2, and different from that reported previously.
Preparation, Structure, and Circular Dichroism Spectra of [Co(L1)(L2)]+-Type Complexes (L1=Iminodiacetato or N-Methyliminodiacetato and L2=3-Azapentane-1,5-diamine or 3-Methyl-3-azapentane-1,5-diamine)
Authors: Yasui Takaji , Okamoto Ken-ichi , Hidaka Jinsai , Ama Tomoharu , Kawaguchi Hiroshi
Published: July 2006

Three geometrical isomers (mer, u-fac, and s-fac) possible in each of [Co(ida)(mdien)]+ and [Co(mida)(mdien)]+ and u-fac isomer of [Co(mida)(dien)]+ (ida=iminodiacetate, mida=N-methyliminodiacetate, mdien=3-methyl-3-azapentane-1,5-diamine, and dien=3-azapentane-1,5-diamine) were newly prepared, and the u-fac isomers were optically resolved. The geometrical structures of these isomers were assigned on the basis of their absorption and 13C NMR spectral data. The crystal structure of (+)550CD-u-fac-[Co(ida)(mdien)]·(+)575CD-[Co(ox)2(en)]·6H2O was determined by X-ray diffraction method. The crystal is monoclinic, space group P21, a=15.793(6), b=12.855(3), c=7.070(2) Å, β=96.80(5)°, and Z=2. Both of the absolute configurations of the two complex ions take Λ configuration. The relationship between the absolute configurations and the CD spectral behaviors of the u-fac isomers is also discussed.
Behavior of the Heat of Formation in the Bismuth–Antimony System
Authors: Badawi Walid Ahmad
Published: July 2006

Calorimetric studies on the behavior of the heat of formation in the bismuth–antimony system have been carried out at eight different compositions (10–80 at-% Sb). Values of the enthalpy and excess enthalpy at those compositions have been determined and tabulated at even temperature intervals of 10 °C in the range 50 to 650 °C. The heat of formation at 200 °C is given through the equation:

H F=11.658x2−14.436x22+2.778x23

The heat of formation is positive and takes a maximum value (2556±11) J mol−1 at 50 at-% Sb. The heat of formation is larger than the heat of mixing. The excess over the value of the heat of mixing is attributed to the larger excess volume in the solid state.
Dissociation Constants of Some Amino Acid and Pyridinecarboxylic Acids in Ethanol–H2O Mixtures
Authors: Niazi M S K , Mollin J
Published: July 2006

The dissociation constants of nicotinic, picolinic, benzoic, and o-, m-, and p-aminobenzoic acids and those of glycine, dl-alanine, β-alanine, aniline, and pyridine were determined potentiometrically and spectrophotometrically in 0, 10, 30, 50, and 72% (w/w) ethanol–water mixtures at 25 °C at various ionic strengths (0.01–0.5 mol dm−3). The pK’s of benzoic, o-, m-, and p-aminobenzoic acids increased with increase of EtOH contents while those of nicotinic acid, picolinic acid, glycine, dl-alanine, and β-alanine passed through minimum (upto 30% w/w EtOH contents). The pK’s of aniline and pyridine were almost the same as those found in literature. The variation in pK’s with the solvent composition is discussed in terms of the free energy of transfer from H2O to EtOH–H2O mixtures. The zwitterion to neutral molecule ratio of these acids is also discussed in terms of variation of composition of mixtures.
Synthesis on 1,4-Diaminocyclitol Antibiotics. II. Synthesis of 7′-Propylfortimicin A
Authors: Kanai Kazuaki , Nishigaki Junji , Ogawa Seiichiro , Suami Tetsuo
Published: July 2006

7′-Propylfortimicin A has been synthesized by a condensation of newly prepared 1-O-acetyl-2,6-bis(2,4-dinitrophenylamino)-2,3,4,6,7,8,9,10-octadeoxy-l-lyxo-decopyranose with 2,5-di-O-benzoyl-1,4-bis-N-(methoxycarbonyl)fortamine B, followed by deprotection.
The Reactions of Alkoxyl Radicals with O2. IV. n-C4H9O Radicals
Authors: Morabito Paul , Heicklen Julian
Published: July 2006

n-C4H9ONO was photolyzed with 366 nm radiation at −8, 23, 55, 88, and 120 °C in the presence of NO, O2, and N2. The quantum yields of n-C3H7CHO, C2H5CHO, and CH3CHO were measured as a function of reaction conditions. The primary photolytic act produces n-C4H9O· radicals which can react with NO by two routes

n-C4H9O·+NO→n-C4H9ONO (2a)

→n-C3H7CHO+HNO (2b)

or isomerize via an internal H-atom abstraction

n-C4H9O·→I· (4)

where I· is the HOCH2CH2CH2CH2· radical, and ln(k4⁄k2, mol dm−3)=1.93±1.60–(4014±509)⁄T. If k2 is taken as 2.6×1010 dm3 mol−1 s−1, then log(k4, s−1)=11.25±0.69–(4014±509)⁄2.303T. In the presence of O2, n-C4H9O· radicals can also react with O2

n-C4H9O·+O2→n-C3H7CHO+HO2 (6)

with ln(k6⁄k2)=(−4.09±0.54)–(1178±176)⁄T. If k2=2.6×10−10 dm3 mol−1 s−1, then k6=4.5×108exp {(−1178±176)⁄T} dm3 mol−1 s−1. The radical I· is removed via

I·→CH3CHO+2CH2O+HO (12a)

→Undetected aldehydes+HO (12b)

I·+O2→n-C3H7CHO+HO (13a)

→C2H5CHO+HO (13b)

where these reactions are composites of a series of steps. The ratio k13a⁄k13b\simeq1.3±0.2 nearly independent of temperature. The ratio k12⁄k13 was not found very accurately, but is \simeq3×10−3 mol dm−3. There was no evidence for the oxidation of I· leading to dioxygenated products.
Support Effect of Zinc Oxide Catalyst on Synthesis of Methanol from CO2 and H2
Authors: Inoue Takashi , Iizuka Tokio , Tanabe Kozo
Published: July 2006

The synthesis of methanol from CO2+H2 was carried out at 340–400 °C under total pressure of 10 atm over ZnO supported on MgO, Al2O3, SiO2, TiO2, ZrO2, and Nb2O5. The ZnO/ZrO2 catalyst showed high activity and selectivity for methanol formation. The hydrogenation of CO2 was more selective for methanol synthesis than that of CO.
An Explanation of the Temperature Dependence of the Mössbauer Spectra of Mixed Valence Biferrocenium Derivatives with a (Valence-State) Order-Disorder Transition
Authors: Masuda Yuichi , Sano Hirotoshi
Published: July 2006

The temperature dependence of the quadrupole splitting values in the Mössbauer spectra for monooxidized biferrocenium derivatives is well explained in term of an order-disorder transition with regard to the valence state of two iron atoms in the cations.
Raman Spectra of the Organic Conductor, (TTM–TTF)I2.47
Authors: Ishii Kikujiro , Nakayama Hideyuki , Wu Peiji , Mori Takehiko , Enoki Toshiaki , Imaeda Kenichi , Saito Gunzi , Inokuchi Hiroo
Published: July 2006

The Raman spectra of a highly conductive molecular complex of the title were measured. The I3− symmetric stretching band and its well-known overtones were observed, indicating that the formula for this complex should be written as (TTM–TTF)(I3)0.823. A brief discussion is given comparing the spectra of the present complex with those of TMA–I–TCNQ and (BEDT–TTF)2I3 complexes.
The Brillouin Scattering of Highly Viscous Mixtures
Authors: Hashitani Ryuki , Koda Shinobu , Nomura Hiroyasu
Published: July 2006

The sound velocities of mixtures of tri-o-tolyl phosphate and diisobutyl phthalate were measured by means of the Brillouin scattering method in the temperature range from 214 to 333 K. The velocity dispersion was observed in the mixtures at temperatures from 273 to 323 K in the gigahertz region. The velocity dispersion was attributed to the structural relaxation, as in the case of pure highly viscous liquids. The reduced variable method proposed by Lamb et al. could not be applied to the storage moduli over wide frequency and temperature ranges. The relaxation curves of the reduced storage modulus obtained at room temperature, where the viscosity obeyed the Arrhenius equation, were well expressed by a single relaxation equation. The structural relaxation mechanism of the highly viscous liquids investigated here is related to the weak cooperative motions of molecules in the liquid state. The activation energy, ΔEr, obtained from the temperature dependences of the relaxation times was about a third of those estimated from the Arrhenius plots of the shear viscosities of the mixtures.
Homogeneous and Electrochemical Electron-Transfer Reaction of Nitrobenzene Anion Radical Dissolved in Nitrobenzene
Authors: Suga Kosaku , Aoyagui Shigeru
Published: July 2006

Nitrobenzene anion radical was stably prepared by the electrolytic reduction of nitrobenzene solution containing various kinds and amounts of tetraalkylammonium perchlorates. The rate constants of homogeneous electron-transfer reactions of these nitrobenzene anion radicals with nitrobenzene molecules as a solvent were determined by ESR method at various temperatures. These rate constants at 25 °C were about 107 dm3 mol−1 s−1 and comparable with the rate constant of electron-transfer reation between nitrobenzene and its anion radial in N,N-dimethylformamide. The quasi-first order rate constants evaluated from these rate constants were about 108 s−1 and were larger than the rate constants of the intramolecular electron-transfer reactions of the anion radical of bis(p-nitrophenyl) compounds except for bis(p-nitrophenyl)methane. The absorption spectrum of the solution of nitrobenzene anion radical in nitrobenzene containing 0.1 M tetrabutylammonium perchlorate or 0.1 M tetraethylammonium perchlorate showed an additional weak peak at about 800 or 900 nm as well as the ordinary peak. The light energies of these additional peaks were in good agreement with the energy values of the optical electron-transfer reactions evaluated according to the theory of Hush from the activation energies of corresponding thermal electron-transfer reactions. The rate constants of electrochemical electron-transfer reactions and the diffusion coefficients of nitrobenzene anion radical in nitrobenzene were also measured.
Ion/Molecule Reactions in Gaseous Isopropyl Alcohol
Authors: Hiraoka Kenzo , Takimoto Hajime , Yamabe Shinichi
Published: July 2006

The ion/molecule reactions observed in 4 Torr CH4 containing known small amounts of i-C3H7OH or i-C3H7OH/H2O mixture were studied over the temperature range 40–400 °C. The experiments were carried out using a pulsed electron beam mass spectrometer. At low temperatures (<150 °C), the major ions are i-C3H7OH2+(i-C3H7OH)n. By increasing the temperature, the slow growth of ions with m⁄z=59, 85, and 101 is observed. These ions are assigned to (CH3)2COH+, (CH3)2CHC+(CH3)2, and C6H13O+, respectively. They are probably produced from reactions of i-C3H7+ with isopropyl alcohol. The (CH3)2COH+ ion may be produced from the electrophilic attack of i-C3H7+ onto the secondary carbon atom of i-C3H7OH. At high temperatures (≈400 °C), the (CH3)2COH+ ion becomes dominant. Acid-catalyzed dehydration of isopropyl alcohol, i-C3H7OH2++H2O→H3O+(H2O)+C3H6, is also observed. Ion/molecule reactions involved in the present experiment are discussed according to the frontier-orbital theory.
ESR Studies of the Reaction of the Calcium Atom with Substituted Benzene Vapors
Authors: Mochida Kunio , Mizuno Yasuhisa
Published: July 2006

The reaction of the calcium atom with substituted benzene vapors was examined by means of ESR. The anion radicals of substituted benzenes as intermediates were directly observed.
Structure Study of Supermonomolecular Layers in Langmuir–Blodgett Films. Surface Active Squarylium Dye–Fatty Acid Binary Mixed System
Authors: Matsumoto Mutsuyoshi , Nakamura Takayoshi , Tanaka Motoo , Sekiguchi Tatsuo , Komizu Hideo , Matsuzaki Sanae Y , Manda Eiichiro , Kawabata Yasujiro , Saito Mitsuyoshi , Iizima Sigeru , Sugi Michio
Published: July 2006

The structures of the Langmuir–Blodgett (LB) films of the ordinary mixed monolayer (LPF) and the supermonomolecular layer (HPF) of a surface active squarylium dye-icosanoic acid binary mixed system were examined by absorption spectroscopy. The absorption spectra of one unit layer of LPF with a molar mixing ratio ranging from 1/10 to 1/1 were almost the same, strongly suggesting that each component exists separately in the films. The LB films of two unit layers of LPF showed two peaks at 590 and 560 nm ascribed to intralayer and interlayer aggregates, respectively, besides the monomeric peak at 640 nm. The absorption spectra of one unit layer of HPF indicated a critical value of the mixing ratio 1/3.5 above which the 700-nm peak is observed. This peak is an indication of a multilayer consisting of pure 1 due to the interlayer interaction. The 560-nm peak observed for LPF is caused by a hindered interlayer interaction of the chromophores between the mixed monolayers.
Radiolysis of Methanol Adsorbed on Zeolite
Authors: Nakazato Chiyoko , Murayama Ryoji , Aoki Masayoshi , Masuda Takahiro
Published: July 2006

Radiolysis of methanol adsorbed on synthesized zeolite was investigated by means of product analysis. Molecular hydrogen, formaldehyde, and ethylene glycol are produced as major products. The G-value for the formation of H2 increases with increasing amount of methanol adsorbed on zeolite and approaches ca. 2.1 at about 10−2 mol of methanol per g of zeolite, where the coverage of methanol is approximately unity and G-values of ca. 1.0 are observed for formaldehyde and ethylene glycol. Addition of an electron scavenger causes decrease in G(H2). However, the hydrogen formation is not completely suppressed by N2O, SF6, or CCl4. Kinetics in solution is useful for the interpretation of results and allows the estimation of the G-value for the generation of electron in zeolite and of its relative reactivity toward methanol and some electron scavengers.
A Study of Inorganic Ion Exchangers. XI. The Hydrothermal Reactions of ZrOCl2 and M(H2PO4)2 (M=Mg, Ca, Sr, Ba)
Authors: Okabe Kiyomi , Kobayashi Etsuro
Published: July 2006

The possibility of the hydrothermal synthesis of layered zirconium phosphates containing various alkaline earth metals (abbreviated as ZrMP; M=Mg, Ca, Sr, Ba) has been studied from ZrOCl2 and M(HPO4)2, and their characteristics have been investigated. The optimum conditions for the synthesis of a highly crystalline product were as follows; the molar ratio of the starting materials of Ca(H2PO4)2 and ZrOCl2 was Ca/Zr=3, and the temperature of the hydrothermal reaction was in the range of 200–270 °C. By the hydrothermal reaction of ZrOCl2 and Mg(H2PO4)2, a new compound of ZrMg0.5H(PO4)2·H2O with a layer-spacing of 11.94 Å was obtained. Layered phosphate (ZrMP) was not obtained by the hydrothermal reaction of ZrOCl2 and Ba(H2PO4)2. The temperature range of the inter-layer dehydration of the layered phosphates (ZrMgP, ZrCaP, and ZrSrP) was similar to that of α-zirconium(IV) bis(hydrogenphosphate) (α-ZrP); i.e. the water in the interlayer was lost at 130–240 °C, and dehydro-condensation took place at a higher temperature above 340 °C. Zirconium phosphate containing Mg2+ or Ba2+ was not obtained by the ion exchange of the protons in α-ZrP with the alkaline earth metal cations (M2+) in MCl2, while Ca2+ and Sr2+ were exchanged with the protons. These alkaline earth metal ions except for Ba2+ were easily exchanged with H+ in α-ZrP, when NaOH was added. The layer-spacing of the Mg2+-exchanged zirconium phosphate was 9.6 Å, which was different from that of the hydrothermal product. The layer distances of Ca2+- or Sr2+-exchanged products were similar to those of the hydrothermal products.
Preparation and Properties of Cobalt(II) Hydroxide–(Sodium Fluoride Tetrasilicic Mica) Intercalation Complexes and of Highly Dispersed Cobalt on Mica
Authors: Ohtsuka Kunio , Koga Johji , Suda Mitsuru , Ono Mikiya , Takahashi Minoru
Published: July 2006

Cobalt(II) hydroxide–(sodium fluoride tetrasilicic mica) intercalation complexes were prepared by titrating cobalt(II) nitrate solutions in the presence of mica with sodium hydroxide under oxygen-free conditions. These complexes were characterized by chemical analysis, XRD, DTA-TGA, IR, and surface area measurements. These confirmed that the brucite-like cobalt(II) hydroxide sheet developed within the interlayer of the silicate. Cobalt atoms reduced at 400–700 °C by H2 migrated from the interlayer of the silicate to the external surface of these where highly dispersed cobalt particles were formed. Ultra-fine cobalt metals (50–200 Å) with a hexagonal close-packed form were prepared at 400 °C by H2. The degree of reduction and the grain diameter of cobalt increased with an increase of the reducing temperature and/or the reducing time.
Alkaline Hydrolysis of Inorganic cyclo-Polyphosphates
Authors: Kura Genichiro
Published: July 2006

The hydrolysis rates of inorganic cyclo-polyphosphates in alkaline solutions were determined. The rates in a NaOH solution were significantly faster than those in a (CH3)4NOH solution. Ion-pair formation between PO− and Na+ renders the P atom more positive by reducing the electron density around the atom and more susceptible to the nucleophilic attack by OH−. In a (CH3)4NOH solution, higher-membered cyclo-polyphosphates with a larger ring structure became rather stable. Arrhenius’ activation energy for each phosphate decreases in the order HCl>NaOH>(CH3)4NOH.
A Calorimetric Study of Ternary Zinc(II) Complexes with Chloride Ions and 2,2′-Bipyridyl in N,N-Dimethylformamide
Authors: Ishiguro Shin-ichi , Nagy László , Ohtaki Hitoshi
Published: July 2006

Formation equilibria of ternary zinc(II) complexes with chloride ions and 2,2′-bipyridyl (bpy) have been calorimetrically studied in N,N-dimethylformamide (DMF) containing 0.4 mol dm−3 (C2H5)4NClO4 as a constant ionic medium at 25 °C. Formation of binary (2,2′-bipyridyl)zinc(II) complexes has also been explored. The calorimetric data were satisfactorily explained in terms of formation of the ternary [ZnCl(bpy)]+ and [ZnCl2(bpy)] complexes together with the binary [Zn(bpy)n]2+ (n=1–3) ones, and their formation constants and enthalpies were determined. The formation of the ternary [ZnCl(bpy)]+ and [ZnCl2(bpy)] complexes is not so favorable in DMF. It is suggested that both [ZnCl(bpy)]+ and [ZnCl2(bpy)] complexes have the four-coordinate tetrahedral structure in DMF.
Cis-to-Trans Isomerization of Bis(diamine)bis(isothiocyanato)chromium(III) Thiocyanate in the Solid State
Authors: De Goutam , Suzuki Masatatsu , Uehara Akira
Published: July 2006

Solid-state thermal reactions of trans- and cis-[Cr(NCS)2(AA)2]SCN where AA is 1,2-ethanediamine (en) or 1,3-propanediamine (tn) were studied. Upon heating, both the cis- and trans-complexes lost half mole of diamine to convert into the double complex trans-[Cr(NCS)2(AA)2][Cr(NCS)4(AA)]. The anion moiety [Cr(NCS)4(AA)]− was isolated from the double complex. The thermal reactions are thus useful for easy preparation of [Cr(NCS)4(AA)]− complex, which has previously been obtained with difficulty from solution reactions.
Synthesis of 5-[(E)-1-Alkenyl]-3(2H)-furanones by the Stereoselective Dehydration with Me3SiCl
Authors: Sakai Takashi , Kohda Kazuhiko , Tsuboi Sadao , Utaka Masanori , Takeda Akira
Published: July 2006

The stereoselective dehydration of 5-(2-hydroxyalkyl)-3(2H)-furanones is accomplished conveniently by the treatment with Me3SiCl in acetonitrile to give 5-[(E)-1-alkenyl]-3(2H)-furanones.
A New Method for the Synthesis of 3,5-Disubstituted 2(5H)-Furanones. Synthesis of (±)-Acarenoic Acid
Authors: Tsuboi Sadao , Wada Hiroshi , Muranaka Koichi , Takeda Akira
Published: July 2006

Heating of 3,5-disubstituted 4-bromo-3-methoxycarbonyldihydro-2(3H)-furanones with NaI in 3-pentanone gave 3,5-disubstituted 2(5H)-furanones in 55.8–93.3% isolated yields. A total synthesis of (±)-acarenoic acid was established in 33% overall yield via 4 steps.
Synthesis of 5,8-Dihydroxy-2-methoxy-1,4-naphthoquinone Derivatives. A Major Naphthoquinone Moiety of Some of Naphthoquinone Antibiotics
Authors: Tanoue Yasuhiro , Terada Akira , Tsuboi Toshiyuki , Hayashida Takayuki , Tsuge Otohiko
Published: July 2006

6-Formyl- and 6-hydroxymethyl-5,8-dihydroxy-2-methoxy-1,4-naphthoquinones were, respectively, prepared from 2-formyl- and 2-hydroxymethyl-1,4,5,6,8-pentamethoxynaphthalenes which were synthesized as key intermediates of the new antibiotics containing 2-methoxynaphthazarin structure.
Synthesis and Spectroscopic Studies of 1,1′-(1,8-Naphthylene)di-1H-1,2,3-triazoles
Authors: Nagawa Yoshinobu , Honda Koichi , Nakanishi Hiroshi
Published: July 2006

The first 1,8-diheteroaromatic naphthalenes, 1,1′-(1,8-naphthylene)di-1H-1,2,3-triazoles (1), were synthesized by 1,3-dipolar cycloadditions of 1,8-diazidonaphthalene to acetylenic esters. The spectral properties of these compounds were studied and compared with those of the corresponding 1-(1-naphthyl)-1H-1,2,3-triazoles (2). The two triazole rings at the peri-positions in 1 are in a face-to-face arrangement according to the results of 1H NMR spectra. The UV spectra of 1 are almost identical with each other and show a red shift from those of corresponding 2. No significant spectral differences between 1 and 2 were observed in the IR spectra. The fragment ion with two azirine groups at the peri-position in the naphthalene ring was observed in the MS spectra of 1.
[2]Metacyclo- and [2]Paracyclo[2](1,3)ferrocenophanes
Authors: Hisatome Masao , Yoshihashi Masamichi , Yamakawa Koji , Iitaka Yoichi
Published: July 2006

[2]Metacyclo- and [2]paracyclo[2](1,3)ferrocenophanes (1 and 2) have been synthesized and characterized by means of X-ray diffraction and spectroscopy. The crystal data of the phanes were determined as follows: 1, monoclinic, P21  a=8.851(4), b=15.742(8), c=5.963(3) Å, β=109.76(5)°, Z=2; 2, orthorhombic, Pbca, a=15.308(8), b=24.716(12), c=8.034(4) Å, Z=8. The benzene rings of the both phanes are distorted in a similar manner to [2.2]cyclophanes but the planarities of the cyclopentadienyl (Cp) rings are maintained. The distance between the substituted Cp ring and the iron atom in 1 is considerably extended (1.678(4) Å) in comparison with ferrocene, whereas that of 2 (1.659(3) Å) is not. The 2-hydrogen of the Cp ring and the 9-hydrogen of the benzene ring in 1 are situated right above each other’s rings. In the 1H NMR spectrum of 1, the 2- and 9-protons shifted to highfield to a considerable extent (δ1.18 and 5.34, respectively) due to the diamagnetic anisotropic effects of the benzene and Cp rings. The electronic spectra of both phanes exhibited bathochromic shifts of the d–d absorption band of the iron (1, 451 nm, 2, 447 nm) as compared to [3]metacyclo- and [3]paracyclo[3](1,3)ferrocenophanes (each 442 nm), which were synthesized as reference compounds in this work.
ESR and FT-IR Studies for Coal Structures. Characteristics of Japanese Coals
Authors: Ito Osamu , Seki Hiroyuki , Iino Masashi
Published: July 2006

The ESR parameters (spin concentration, line width, g-value, and spin-lattice relaxation time) of various coals mined in Japan and in many foreign countries have been measured. Low spin concentrations, broad line widths, and long spin-lattice relaxation times have been recognized as characteristics of Japanese bituminous coals (e.g., Akabira, Miike, and Shin-yubari coals) compared with the foreign coals having similar carbon contents. The origins of these differences were interpreted by the aid of the FT-IR spectra. Low fractions of aromatic carbon and rich aliphatic groups of Japanese bituminous coals are closely related to the characteristics in the ESR parameters.
Crystal Structure and 35Cl NQR of Copper(II) Trichloroacetate Trihydrate
Authors: Kiriyama Hideko , Hashimoto Masao , Okuno Nanami
Published: July 2006

The crystal structure of the title compound has been determined by means of X-ray diffraction. The crystal data and the final R value are: Cu(CCl3COO)2·3H2O, monoclinic C2⁄c, a=23.082(3), b=6.253(1), c=9.726(2) Å, β=94.67(1)°, Z=4, R=0.049. The structure consists of monomeric Cu(CCl3COO)2(H2O)3 molecules, which are linked together by intermolecular O–H···O hydrogen bonds to form a layer parallel to (100). Each Cu(II) atom is coordinated by five oxygen atoms which form nearly a square pyramid; two oxygen atoms of two carboxylate ions and two water molecules form its basal plane and the remaining water molecule occupies the apical position. The mean basal Cu–O length is 1.961 Å and the apical one 2.183 Å. The Cu(II) atom is displaced from the basal plane by 0.110 Å toward the apical oxygen. Thermal analysis (DSC) disclosed two phase transitions at 163 and 207 K, their estimated molar enthalpies being about 0.4 and 0.7 kJ mol−1, respectively. At 77 K, 24 35Cl NQR signals are observed in the frequency range 38.7–40.3 MHz. The X-ray diffraction photographs for both low-temperature phases indicate the appearance of superstructures with less symmetrical space groups; the b spacing doubles below 207 K, while both b and c spacings double below 163 K.
Oscillatory Variation near the C–K Edge in the Photon W-Value of Ethylene
Authors: Suzuki Isao H , Saito Norio
Published: July 2006

The dependence of ethylene W-value on photon energy has been precisely measured in the region from 269 to 324 eV by using monochromatized synchrotron radiation. The W-value showed an oscillatory variation at the Cls→π* excited state as well as the C–K edge. A model has been proposed in which the inner-shell excitation gives rise to a change in the energy of the electron ejected from the molecule having absorbed a photon. It has been found that the model can reproduce the oscillatory variation feature of the W-value.
Lanthanoid Chirality as a Tool for Assignment of f–f Transitions. Tb3+ and Tm3+ Diglycolate
Authors: Karmakar Bhutnath , Chatterjee Prabir K , Basu Samita , Chowdhury Mihir
Published: July 2006

Although chiral studies have proved to be handy in the assignment of transitions in biological molecules, organic molecules and transition metal complexes, its potentiality for lanthanoid transition needs to be demonstrated. The paper explores the usefulness of CD studies in the assignment of lanthanoid transitions with two specific chiral single crystals–thulium diglycolate (Tm3+–DG) and terbium diglycolate (Tb3+–DG). It has been shown that chirality can distinguish ΔJ=0, ±1 transition from others. The need for studies under higher resolution has been pointed out.
Photochemical Reactions. 21. Sensitized Photooxygenation of N-Methylated 4-Aza-5-androsten-3-one and 4-Aza-5-androstene Steroidal Systems
Authors: Piniella Joan Francesc , Estapé Jordi , Lupón Pilar , Merino Luis , Puig Mariano , Bonet Juan-Julio , Briansó José Luis , Germain Gabriel
Published: July 2006

Two steroidal ene lactams, N-methyl-4-aza-5-androsten-3,17-dione and N-methyl-6-methoxy-4-aza-5-androsten-3,17-dione, and an enamine, N-methyl-4-aza-5-androsten-17β-ol, have been synthetized and their sensitized photooxygenations were investigated. The two ene lactams yield fragmentation compounds via the corresponding dioxetanes. Comparison with the previously reported behavior of an analogous N-unsubstituted ene lactam, seems to indicate that N-substitution is essential for the fragmentation to take place. On the other hand, the enamine yields a ketol. All results are briefly discussed from the mechanistic point of view.
Synthetic Photochemistry. XXXVIII. The Photorearrangement of the Tropone Endoperoxide, 6,7-Dioxabicyclo[3.2.2]nona-3,8-dien-2-one
Authors: Mori Akira , Takeshita Hitoshi
Published: July 2006

The photolysis of 6,7-dioxabicyclo[3.2.2]nona-3,8-dien-2-one produced six photolysates, including a cage γ-lactone which belongs to the same type of product as was characterized in each case of the photolysis of the endoperoxides derived from 2-aryl- and 2,7-diaryltropones by Mukai et al. The new products identified were 2,7-dioxabicyclo[3.2.2]nona-3,8-dien-6-one, a δ-lactone acetal, and 7-exoformyl-3-oxabicyclo[4.1.0]hept-4-en-2-one, a δ-lactone.
Fries Rearrangement of 1-Methoxy-4-(4-methyl-2- and -3-pentenoyloxy)benzenes
Authors: Tanoue Yasuhiro , Terada Akira
Published: July 2006

Not only rearrangement but also cyclization occurred in a Fries rearrangement of 1-methoxy-4-(4-methyl-2- and -3-pentenoyloxy)benzenes and gave 5,8-dihydroxy-4,4-dimethyl-3,4-dihydro-1(2H)-naphthalenone. The reduction and oxidation of the dihydronaphthalenone gave 5-hydroxy-8,8-dimethyl-5,6,7,8-tetrahydro-1,4-naphthalenedione and 8,8-dimethyl-7,8-dihydro-1,4,5(6H)-naphthalenetrione, respectively.
The Thermal Decomposition of Lithium Hydrogenphosphoramidate Trihydrate
Authors: Shimasaki Choichiro , Suzuki Hiroki , Toda Hiroshi
Published: July 2006

The thermal decomposition of lithium hydrogenphosphoramidate trihydrate LiHPO3NH2·3H2O was investigated by means of DTA–TG, X-ray diffraction analysis, IR, 31P NMR, and compositional analysis. The decomposition proceeds via an anhydrous phase, a newly found intermediate phase, and polyphosphates to lithium metaphosphate. The activation energies of the dehydration of the water of crystallization and of the polymerization reaction for the thermal decomposition were estimated to be 96.2 and 105.4 kJ mol−1 respectively.
Determination of Mercury by Graphite Furnace Atomic Absorption Spectrometry after Ion-Pair Extraction with Zephiramine in Small Scale
Authors: Okamoto Yasuaki , Kumamaru Takahiro , Hara Shigeki , Matsuo Hiroshi , Kiboku Mitsuo
Published: July 2006

A simple procedure for the determination of mercury(II) by graphite furnace atomic absorption spectrometry is described. Mercury(II) was extracted as tetradecyldimethylbenzylammonium (Zephiramine) thiocyanatomercurate(II) into diisobutyl ketone (DIBK) by using a 10-cm3 centrifuge tube, and an aliquot of the organic extract was directly pipetted out from the upper layer in the centrifuge tube and injected into the graphite furnace. The heating temperature program by ramp mode and the background correction by means of a 2-channel type atomic absorption spectrometer gave satisfactory results.
ESR Spectroscopic Study of Triphenylmethyl-Substituted Thioaminyl Radicals: N-(Triphenylmethylthio)alkylaminyls and -arylaminyls
Authors: Miura Yozo , Isogai Mamoru , Kinoshita Masayoshi
Published: July 2006

The title radicals, generated by hydrogen-atom abstraction from the corresponding N-(triphenylmethylthio)alkylamines and -arylamines, have been studied by means of ESR spectroscopy. The alkylaminyls were transient in solution at room temperature, while the arylaminyls persisted for a long period under the same conditions. The ESR parameters are discussed by comparing them with those for structurally related aminyls.
Application of the Flow Injection Analysis Based on Iodometry to the Determination of Ozone Decomposition Rate
Authors: Onari Yasuo
Published: July 2006

The determination of ozone decomposition rate by flow injection analysis (FIA) was investigated. Under the conditions studied a sampling rate was about 43 samples/h, and the pseudo-first-order kinetic plot of the obtained data showed a good linearity. This FIA method seems to be useful for kinetic measurement of ozone decomposition in water.
Improved Spectrophotometric Determinations of Cobalt(II) and Nickel(II) with Zincon in the Surfactants Micellar
Authors: Mori Itsuo , Fujita Yoshikazu , Fujita Kinuko , Tanaka Takeshi , Yano Yukari , Asada Makiko
Published: July 2006

Reactions between Zincon and cobalt(II) in the presence of N-hexadecylpyridinium chloride (cationic surfactant), and between Zincon and nickel(II) in the presence of poly(vinyl alcohol) (nonionic surfactant) are discussed in terms of the development of simple, sensitive and improved spectrophotometric determinations of cobalt(II) and nickel(II). The calibration graphs were rectilinear in the ranges 0–2.2 μg 10 cm−3 cobalt(II) with a Sandell sensitivity of 0.00015 μg cm−2 at 550 nm and 0–42.0 μg 10 cm3 nickel(II) with that of 0.0047 μg cm−2 nickel(II) at 470 nm. The proposed methods were relatively sensitive in comparison with the methods in the absence of surfactants with apparent molar extinctions of 4.6×105 for cobalt(II) and 2.4×104 dm3 mol−1 cm−1 for nickel(II). Separative assays of cobalt(II) and various metals (nickel(II), zinc(II), copper(II), and iron(III)) were possible by selections of analytical wavelengths, respectively.
Trace Determination of Indium by Electrolytic Preconcentration and Open Circuit Stripping via Localized Galvanic Cells
Authors: Jaya Sambamoorthy , Rao Talasila Prasada , Rao Gollakota Prabhakara
Published: July 2006

A galvanic stripping analysis procedure is described for the trace determination of indium(III). The determination involves the reoxidation of predeposited indium on the mercury-film-coated glassy carbon electrode in open circuit position (in the absence of external potential or current input or oxidant in solution). The reoxidation of indium was shown to occur due to the formation of localized galvanic cells. The time of reoxidation (stripping) was found to be proportional to the concentration of indium present in the solution (1 to 100 ppb). The details of the development of such a procedure and its possible application to determination of indium in zinc deposits and aluminium alloys are discussed.
Phenomenological Relationship between the Fluidity and Tracer-Diffusion in Concentrated Electrolyte Solutions
Authors: Tanaka Kazuko , Tamamushi Reita
Published: July 2006

An attempt has been made to correlate the mobility of component species with the fluidity of the solution over a wide range of concentration in aqueous solutions. A good linear correlation was observed between the relative fluidity and the relative tracer-diffusion coefficient of Cl− in aqueous solutions of LiCl, NaCl, MgCl2, CaCl2, and NiCl2, particularly at higher concentrations over 2 mol kg−1. The correlation for the cations was very similar to that of water in aqueous solutions of such electrolytes. The feature of these plots presents that the structural properties of concentrated electrolyte solutions are reflected on these correlations.
Hydrophobic Vitamin B12. V. Electrochemical Carbon-Skeleton Rearrangement as Catalyzed by Hydrophobic Vitamin B12: Reaction Mechanisms and Migratory Aptitude of Functional Groups
Authors: Murakami Yukito , Hisaeda Yoshio , Ozaki Toshiaki , Tashiro Takako , Ohno Teruhisa , Tani Yutaro , Matsuda Yoshihisa
Published: July 2006

The carbon-skeleton rearrangements as catalyzed by heptamethyl cobyrinate perchlorate, [Cob(II)7C1ester]ClO4, were investigated under electrochemical conditions. The controlled-potential electrolysis of 2,2-bis(ethoxycarbonyl)-1-bromopropane, which is considered to be a model substrate for methylmalonyl–CoA mutase, was catalyzed by [Cob(II)7C1ester]ClO4 in N,N-dimethylformamide to give the rearrangement product, 1,2-bis(ethoxycarbonyl)propane, as a major one at −1.5V vs. SCE in the presence of acetic acid and at potentials more cathodic than −1.8V vs. SCE without acetic acid in the dark. The electrochemical carbon-skeleton rearrangement was postulated to proceed via formation of anionic intermediates. The electrolyses of 1-bromo-2-cyano-2-ethoxycarbonylpropane, 2-acetyl-1-bromo-2-ethoxycarbonylpropane, and 1-bromo-2-[(ethylthio)carbonyl]propane with [Cob(II)7C1ester]ClO4 also afforded the corresponding carbon-skeleton rearrangement products. The results indicated that substrates with two electron-withdrawing groups placed on the β-carbon atom with combinations of one carboxylic ester and one of carboxylic ester, acetyl, and cyano moieties readily gave the corresponding rearrangement products which were derived from individual migration of the substituent groups. Substrates with only one of the electron-withdrawing groups, carboxylic ester, acetyl, and cyano, did not give any rearrangement product but a substrate with one thioester group afforded the corresponding rearrangement product. The migratory aptitude of electron-withdrawing groups was found to decrease in the order: COSR>COR>COOR>CN. Both electronic character and steric bulkiness of the migrating groups are apparently reflected on this tendency, even though relative contributions of these effects are much dependent on the nature of β-substituents.
Effect of Molybdenum Codeposition on the Thermal Properties of Electroless Ni–B Alloy Plating Films
Authors: Osaka Tetsuya , Koiwa Ichiro , Yamada Keizo , Nishikawa Masao , Usuda Masahiko
Published: July 2006

Electroless Ni–Mo–B alloy films from a bath using dimethylamine–borane(1/1) (DMAB) as a reducing agent were investigated. Only a small amount of Mo-complex addition to the bath decreased the boron content and increased the molybdenum content drastically. The maximum molybdenum content and maximum resistivity under as-plated conditions were obtained as 22.1 wt% and 322 μΩ cm respectively. Such a high resistivity is characteristic of Ni–Mo–B alloy films. Both crystallized and amorphous states of Ni–Mo–B alloy films, whose Mo contents were above 20 wt% with a small amount of boron, were prepared by controlling the Mo-complex concentration in the bath. The heat change properties of Ni–Mo–B alloy films were quite different from those of the electroless Ni alloy films reported previously. The resistivity of Ni–Mo–B alloy films after heat treatment at 500 or 600 °C became higher than that of those created under as-plated conditions. The structure transformation of Ni–Mo–B alloy films after heat treatment was quite different from that of ordinary electroless Ni alloy films. The Ni–Mo–B alloy film after heat treatment was confirmed by TEM observation to show a mosaic-like structure. Therefore, it was thought that such a high resistivity and such thermal properties of Ni–Mo–B alloy films are caused by such a mosaic-like structure.
Influence of Br− Concentration on (Br)+-Mediated Indirect Electrooxidation of Alcohols to the Corresponding Carbonyl Compounds
Authors: Takiguchi Tsuyoshi , Nonaka Tsutomu
Published: July 2006

Current efficiency for the (Br)+(positive bromine species)-mediated indirect electrooxidation of alcohols to the corresponding carbonyl compounds decreased with increase in Br− concentration in dichloromethane and aqueous acidic solutions, while no concentration dependence was observed in an aqueous neutral solution. These facts suggested a general and practical guideline for the indirect electrooxidation, i.e. low Br− concentration is favorable in an electrolytic solution of low nucleophilicity. It was also found that the kind of (Br)+ species formed anodically in the absence of the alcohols in dichloromethane clearly depended on charge(Q) passed as follows: Br3− at Q≤2⁄3F mol−1 (1F=96480 C), Brn− (n>3) at 2⁄3<Q<1F mol−1, and Br2 at Q=1F mol−1. Among these species, Br3− and Br2 seemed to be the weakest and strongest oxidizing agents, respectively. Lower efficiency for the indirect electrooxidation in higher Br− concentration was rationalized as due to more predominant formation of Br3− and/or Brn− with smaller n values.
Photochemical Stability of Polycyclic Aromatic Hydrocarbons in the Interstellar Medium
Authors: Aihara Jun-ichi
Published: July 2006

The astronomical IR spectra of molecular origin have been attributed to compact polycyclic aromatic hydrocarbons. This interpretation can be rationalized in terms of the percent resonance energies of the excited-state species. In general, large compact polycyclic aromatic hydrocarbons are not only thermodynamically stable but also photochemically stable. These hydrocarbons have large percent resonance energies in the excited state, and are expected to survive the rough conditions in space. In contrast, relatively small aromatic hydrocarbons are greatly destabilized when they are excited electronically or deprived of two π electrons.
Clogging and Gel-Layer Formation during Membrane Filtration and Its Effect on Analytical Data
Authors: Igawa Manabu , Yoshida Takeshi , Ohtake Chiaki , Hayashita Takashi
Published: July 2006

Clogging and gel-layer formation during membrane filtration affect the concentration of ions in the filtrate as well as the concentration of suspended solids. The flow rate analysis and the observation of the filter surface with a scanning electron microscope show that a gel-layer is formed subsequently after the clogging. Humic acids, fulvic acids, metal hydroxides, and soft particles dispersed in natural waters cause the clogging and hence the gel-layer formation. Cross-flow filtration decreases the rate of the clogging and the gel-layer formation and gives little rise to the filtration effects on analytical results.
Preparation and Characterization of U2O2F7
Authors: Asada Kameo , Ema Keiko , Iwai Takashi
Published: July 2006

Reaction of UO2F2 with UF5 at 400 °C under UF6-pressure of 3 atm followed by evaporation of excess UF5 has yielded a greenish white residue. Its X-ray diffraction pattern and infrared spectrum are sufficiently unique to establish that this material is a true compound. Its chemical formula has been shown to be U2O2F7, on the grounds of chemical analysis and thermal decomposition. The oxygen content was determined directly by means of 18O isotopic dilution method based on the combustion of the samples with BrF5.
The Iodine Content of Atmospheric Aerosols as Determined by the Use of a Fluoropore Filter® for Collection
Authors: Tsukada Hirofumi , Hara Hiroshi , Iwashima Kiyoshi , Yamagata Noboru
Published: July 2006

Atmospheric aerosols were collected onto a Fluoropore filter in order to determine the iodine by means of instrumental neutron activation analysis. The collection filter was found to be the best material among the nine filters examined, for it has the lowest blank values for iodine as well as for other halogens and sodium. The iodine concentrations in Tokyo were found to be 1.7–12.7 ng m−3. Of the soluble iodine, 10% or less was in the form of IO3−.
Chromatographic Study of Optical Resolution. XIV. Optical Resolution of Amine Complex Cations of the Type [Co(N)6]3+ by Reversed-Phase Ion-Pair Chromatography Using Bis(μ-d-tartrato)diantimonate(III) and Arsenic Analog as an Ion-Pairing Reagent
Authors: Izumoto Shinji , Miyoshi Katsuhiko , Yoneda Hayami
Published: July 2006

Reversed-phase ion-pair chromatography (RPIPC) was applied to the optical resolution of amine complex cations of the type [Co(N)6]3+ using either bis(μ-d-tartrato)diantimonate(III) ion, [Sb2(d-tart)2]2− or its arsenic analog, [As2(d-tart)2]2− as an ion-pairing reagent. With either reagent, efficient optical resolution was attained for [Co(en)3]3+, [Co(tn)3]3+, [Co(sen)]3+, [Co(sep)]3+, and [Co(diNOsar)]3+ (en=ethylenediamine, tn=trimethylenediamine, sen=1,1,1-tris[[(2-aminoethyl)amino]methyl]ethane, sep=1,3,6,8,10,13,16,19-octaazabicyclo[6.6.6]icosane, and diNOsar=1,8-dinitro-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane). Dependence of retention volumes and separation factors of these complexes on the concentration and the counterion of the ion-pairing reagents was examined with Na+, Me4N+, and Et4N+ employed as counterions. Experimental results were discussed with reference to those obtained by means of normal-phase ion-exchange chromatography (NPIEC) using the same eluents. It was concluded that [As2(d-tart)2]2− serves as a more effective eluent in both RPIPC and NPIEC than [Sb2(d-tart)2]2−, and that RPIPC is a much more useful tool for the optical resolution of the [Co(N)6]3+-type complex cations than NPIEC.
Infrared Absorption Study of Human Hemoglobin α-Chain (123–136) Fragments in Dichloromethane
Authors: Narita Mitsuaki , Doi Masamitsu , Nakai Takao
Published: July 2006

In connection with the relationship between the conformation and solubility of peptide intermediates having polar side chains, IR spectroscopic conformational analysis of peptide fragments of human hemoglobin α-chain (123–136) was performed in dichloromethane. In dichloromethane, the conformational behavior of the peptide fragments was, in essence, dependent on their amino acid sequences, and Boc–Ser(Bzl)–Thr(Bzl)–Val–Leu–OPac through Boc–Ala–Ser(Bzl)–Val–Ser(Bzl)–Thr(Bzl)–Val–Leu–OPac had predominantly unordered structures including some intramolecular hydrogen bonds, while Boc–Ala–Ser(Bzl)–Leu–Asp(OBzl)–Lys(Z)–Phe–Leu–OPac had successive intramolecular hydrogen bonds, probably corresponding to an α-helical structure. On the other hand, in carbon tetrachloride, the conformation of Boc–Val–Ser(Bzl)–Thr(Bzl)–Val–Leu–OPac and Boc–Ser(Bzl)–Val–Ser(Bzl)–Thr(Bzl)–Val–Leu–OPac had a typical β-sheet structure. These results are discussed on the basis of the amino acid sequences of the peptide fragments.
Palladium-Promoted Transformation of β-Amino Ketones to Enaminones
Authors: Murahashi Shun-Ichi , Mitsue Yo , Tsumiyama Tatsuo
Published: July 2006

The reaction of β-amino ketones with bis(acetonitrile)dichloropalladium(II) in the presence of triethylamine gives the corresponding enaminones regioselectively. The cyclic β-amino ketones can be converted into the corresponding exocyclic enaminones. The enaminones thus obtained are versatile synthetic intermediates. The reaction of (E)-enaminones with organocuprates gave the corresponding (E)-α,β-unsaturated ketones.
Nitrone Cycloaddition Route to the 1β-Methylcarbapenem Key Intermediate
Authors: Ito Yoshio , Kimura Yoshikazu , Terashima Shiro
Published: July 2006

The 1β-methylcarbapenem key intermediate, (3S,4S)-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-4-[(R)-1-carboxyethyl]-2-azetidinone, was prepared from (S)-methyl 3-hydroxy-2-methylpropionate by employing 1,3-dipolar cycloaddition of the chiral nitrone with benzyl crotonate as a key reaction.
Electrochemical Redox Intercalation of Copper(I) Cation for CuxMo6S8 Superconductor Accompanied with a Reversible Structure Change
Authors: Inoue Tooru , Yamase Toshihiro
Published: July 2006

Ternary compounds (Chevrel phase compounds) of molybdenum CuxMo6S8 were prepared by sintering mixed powders of MoS2, Mo, and CuS and employed as electrodes in aqueous solutions. Electrochemical polarization of the electrodes gives rise to intercalation and deintercalation processes of Cu+, resulting in deformative change in crystal structure of the compounds. The lattice constants of rhombohedral unit cells of the compounds are ar=6.66 Å, αr=96°, and Vr=290 Å3 for the intercalated compound Cu4Mo6S7.8, and ar=6.43 Å, αr=91.2°, and Vr=267 Å3 for the fully deintercalated Mo6S7.8. Both the copper(I) composition and the crystal structure of CuxMo6S7.8 can be controlled by the electric quantity in electrochemical redox treatment. Structure deformation results from change in electronic distribution of crystal, as well as in charge density of a Mo octahedral cluster, due to electrolysis.
A Stopped-Flow Kinetic Study on the Binding of Phenylbutazone to Human Serum Albumin Using Absorption and Circular Dichroism Techniques
Authors: Murakami Kiyofumi , Fujisaki Yasuo , Sano Takayuki
Published: July 2006

The mechanism of the binding of phenylbutazone(4-butyl-1,2-diphenyl-3,5-pyrazolidinedione) to human serum albumin has been investigated by kinetic experiments using both optical absorption and circular dichroism (CD) stopped-flow methods. Three distinct processes were found to exist by the absorption technique; one of these was within the dead time of the apparatus and other two slow processes were at around 10−2 and 1 s, of which the relaxation times were determined. On the other hand, only two processes, which correspond in time range to the first and third processes seen by optical absorption, were found using CD technique. By examining the concentration dependence of the reciprocal relaxation time of each process and by taking account of the binding isotherm, a binding mechanism has been proposed. According to the elucidated reaction scheme, successive binding of two molecules of phenylbutazone is followed by a conformational change which destabilizes one of the bound species. The detailed nature is discussed in the light of the circular dichroism change of each process.
Acyclic C-Nucleoside Analogs of the Type of 5-C-Polyhydroxyalkyl-1,3,4-thiadiazoles
Authors: El Ashry Elsayed S H , Nassr Mahmoud A , El Kilany Yeldez , Mousaad Ahmed
Published: July 2006

The synthesis of some acyclic C-nucleoside analogs possessing thiadiazole rings was achieved by the heterocyclization of the 4-arylthiosemicarbazones of d-galactose, d-glucose, d-mannose, d-arabinose, and lactose, Acetylation of the thiadiazoles afforded the corresponding 2-(N-acetylarylamino)-5-polyacetoxyalkyl-1,3,4-thiadiazoles and periodate oxidation gave the corresponding 5-(arylamino)-1,3,4-thiadiazole-2-carbaldehyde.