bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidation of Lipids. V. Oxidation of Methyl Linoleate in Aqueous Dispersion
Authors: Yamamoto Yorihiro , Haga Shunichi , Niki Etsuo , Kamiya Yoshio
Published: July 2006

The rate and products of oxidation of methyl linoleate dispersed in water by Triton X-100 were measured at 50 °C. The oxidation was initiated by water- or oil-soluble azo-initiators. The oxidation proceeded smoothly by both types of initiators without any noticeable induction period and a constant rate of oxygen uptake was observed. Conjugated diene hydroperoxides were formed almost quantitatively. The oxidizability for methyl linoleate in aqueous dispersion was obtained as kp/(2kt)1⁄2=0.032(s·mol/L-oil)−1⁄2 where kp and kt are the rate constants for propagation and termination reactions, respectively. This value was similar to that observed in the homogeneous oxidation in chlorobenzene. l-Ascorbic acid inhibited the oxidation initiated by water-soluble initiator but it could not inhibit the oxidation initiated by oil-soluble initiator. 2,6-Di-t-butyl-4-methylphenol inhibited the oxidation initiated by both initiators. On the other hand, α-tocopherol was effective for the oxidation initiated by oil-soluble initiator and it incompletely inhibited the oxidation initiated by water-soluble initiator.
The Formation of the Main Skelton of Bicyclomycin by the Cyclization of 6-Hydroxy-3-(3-hydroxypropyl)-2,5-piperazinedione Derivatives
Authors: Sato Yoshiaki , Shin Chung-gi , Sumiya Satoshi , Nakajima Yoshiharu , Yoshimura Juji
Published: July 2006

This paper describes the synthesis of 3-(3-t-butoxypropyl)-6-hydroxy-2,5-piperazinedione derivatives by the hydroxylation of the corresponding 2,5-piperazinedione with N-bromosuccinimide (NBS) in the presence of water and the subsequent cyclization to 2-oxa-7,9-diazabicyclo[4.2.2]decane-8,10-dione derivatives (11). The reversible interconversion between the spiro[oxolane-2,2′-piperazine]-3′,6′-dione prepared previously and the bicyclo compound 11 was established. The formation mechanisms and the structural confirmation of 11 and the other products are discussed.
NAD(P)+-NAD(P)H Models. 49. Proximity Effect of a Phenyl Group on the Electron Transfer Process
Authors: Ohno Atsuyoshi , Kobayashi Hisami , Goto Takehiko , Oka Shinzaburo
Published: July 2006

1-Propyl-1,4-dihydronicotinamide (PNAH), 1-(3-phenylpropyl)-1,4-dihydronicotinamide (1a), 1-(2-phenylthioethyl)-1,4-dihydronicotinamide (1b), and 1-(4-phenylthiobutyl)-1,4-dihydronicotinamide (1c) and their 4-deuterated analogs are synthesized as NAD(P)H-models and subjected to the reduction of m-nitro-α,α,α-trifluoroacetophenone in the presence or absence of magnesium ion in acetonitrile. Kinetics at 323 K have been studied. Kinetic isotope effect is small (2.33) only when 1a or 1b is employed for the reduction in the presence of magnesium ion, whereas it appears large (≈3.2) under other conditions. The result has been interpreted in terms of steric interference by a proximate phenyl group on the approach of the substrate to form a binary (in the absence of magnesium ion) or ternary (in the presence of magnesium ion) complexes. Thermodynamic parameters for the formation of complexes between the models and magnesium ion have been studied. It has been elucidated that enthalpy of complexation is small for 1a than others. However, the small enthalpy of complexation is compensated by small entropy of complexation affording almost constant free-energy of complexation throughout the models studied.
The Crystal Structure of N,N,N′,N′-Tetramethylpiperazinediium Bis(2,4-dinitrophenolate) Dihydrate
Authors: Iwasaki Fujiko , Mutai Kiyoshi
Published: July 2006

The crystal structure of N,N,N′,N′-tetramethylpiperazinediium bis(2,4-dinitrophenolate) dihydrate has been determined by the X-ray method. The crystals are triclinic, space group P\barl, a=11.504(2), b=8.239(2), c=7.119(2) Å, α=106.22(2), β=99.67(2), γ=92.31(2)°, Z=1. The final R is 0.067 for 2743 reflections. Two dinitrophenolate anions are connected by hydrogen bonds, via the water molecules, forming a dimeric unit related by the center of symmetry. N,N,N′,N′-Tetramethylpiperazinediium ion has a chair conformation.
The Adsorption of Dodecyldimethylammonium Bromide on Aqueous Surfaces of Sodium Bromide Solutions
Authors: Okuda Hideshi , Ozeki Sumio , Ikeda Shoichi
Published: July 2006

The surface tension of aqueous NaBr solutions of dodecyldimethylammonium bromide has been measured by the drop weight method at different surfactant and NaBr concentrations. By applying the Gibbs adsorption isotherm, surface excess densities of surfactant cation, Na+ and Br− are derived as functions of surfactant concentration at different NaBr concentrations. The rational mean activity coefficients of surfactant and NaBr are both approximated by a common expression satisfying the Brφnsted principle for mixed electrolytes and containing the ionic strength as a variable. Surface excess density of surfactant cation increases with increasing surfactant concentration and has a general tendency still increasing even at the critical micelle concentration. Some comparison of the behavior of surface excess densities of ions between the present bromide system and the previous chloride system is made. The Corrin-Harkins plot for the critical micelle concentration consists of two straight lines intersecting at 0.015 mol dm−3 NaBr.
Asymmetric Hydrogenation of Schiff Base Prepared from α-Keto Ester with Aliphatic Amino Acid Ester
Authors: Harada Kaoru , Shiono Shozo
Published: July 2006

Catalytic hydrogenation of Schiff bases prepared from α-keto esters with amino acid esters was carried out under various conditions. A significant substituent effect of the alkyl group of the ester moiety of amino acid on the stereoselectivity was observed in the hydrogenation of the Schiff bases prepared from methyl pyruvate with (S)-alanine ester. Higher asymmetric yields were obtained as the ester residue of amino acid ester became bulkier. A clear temperature effect on the asymmetric hydrogenation was also observed. These results could be explained by the chelation mechanism.
Synthesis and Properties of the Tristyrylmethyl Anion
Authors: Komatsu Koichi , Shirai Shuzo , Tomioka Isao , Okamoto Kunio
Published: July 2006

The title anion (3) having a C3v symmetric structure was generated from newly synthesized tristyrylmethane (4) and was characterized by means of 1H and 13C NMR spectroscopy. The pKa value of 4 was determined as 20.1 in DMSO–EtOH (9:1), indicating considerable conjugative stabilization of the anion 3. The cyclic voltammetry of 3 in acetonitrile exhibited only irreversible one-electron oxidation peak corresponding to the formation of a chemically unstable radical species. Whereas quenching the anion 3 with H2O or Me3SiCl quantitatively afforded the cross-conjugated triene 6 (R=H or Me3Si), the reaction of 3 with the tropylium ion yielded 1,1′-bicycloheptatrienyl (29%), as well as the triene 6 (R=C7H7) (66%), demonstrating that 3 can also acat as a one electron reductant.
Liquid Crystal Formation in Binary Systems. IX. Effects of Branching of Ester Alkyl Group on the Induction of Liquid Crystals in the Alkyl 4-[4-(Dimethylamino)benzylideneamino]benzoate-4,4′-Dinitroazoxybenzene Systems
Authors: Matsunaga Yoshio , Suzuki Izumi
Published: July 2006

Smectic A liquid crystals are formed not only in systems with normal alkyl esters but also with esters of branched alkyl groups such as t-butyl, 1,2-dimethylpropyl, and 1-ethylpropyl.
The Reaction of Fluorenethione S-Tosylimide with Grignard Reagents
Authors: Saito Takao , Nakane Michio , Motoki Shinichi
Published: July 2006

Fluorenethione S-tosylimide reacted with Grignard reagents to afford both the thiophilic and carbophilic products depending on the solvent used.
X-Ray Structural Elucidation of a Novel Steric Effect of o-Methoxyl Substituents in 2,6-Dimethoxyphenylnickel(II) Complexes Mediated by m-Bromo Substitution
Authors: Xu Duanjun , Kai Yasushi , Miki Kunio , Kasai Nobutami , Nishiwaki Koichi , Wada Masanori
Published: July 2006

Molecular structures of novel trans-[NiR2L2] complexes, trans-[Ni{C6H3(OMe)2-2,6}2(PR3)2] [PR3=PMe3 (1a), PMe2Ph (1b)], and their m-brominated derivatives, trans-[Ni{C6H(OMe)2-2,6-Br2-3,5}2(PR3)2] [PR3=PMe3 (2a), PMe2Ph (2b)], were determined by X-ray crystal structure analysis. A remarkable effect of m-substitution on the conformation of the o-methoxyl groups was found. This correlated well with the reactivity difference toward carbon monoxide. Crystal data: 1a: monoclinic, space group P21/c, a=8.737(2), b=18.282(3), c=16.319(4) Å, β=105.06(2)°, Z=4, R=0.062; 1b: triclinic, space group P\bar1, a=16.993(5), b=10.180(3), c=17.177(5) Å, α=112.44(2), β=117.59(2), γ=66.25(2)°, Z=3, R=0.060; 2a: monoclinic, space group P21/c, a=9.294(2), b=14.091(3), c=10.770(2) Å, β=92.06(3)°, Z=2, R=0.067; 2b: triclinic, space group P\bar1, a=9.370(1), b=11.387(2), c=9.013(1) Å, α=94.52(2), β=107.24(2), γ=77.35(2)°, Z=1, R=0.058.
1,3-Dipolar Cycloaddition Reactions of 6-Methylenetricyclo[3.2.1.02,7]oct-3-en-8-one and Its Related Compounds
Authors: Nitta Makoto , Omata Akihiko , Okada Shuji
Published: July 2006

The cycloaddition reactions of 1,5-dimethyl-6-methylenetricyclo[3.2.1.02,7]oct-3-en-8-one (1a), its corresponding -8-endo-ol (1b), 1,5,8-trimethyltricyclo[3.2.1.02,7]oct-3-en-8-endo-ol (1c), and 5,8-dimethyl-9-methylenetricyclo[3.3.1.02,8]non-3-en-7-one (2) were investigated in order to study the origin of its stereoselectivity or site selectivity. The reaction of 2,4,6-trimethylbenzonitrile oxide (mesitonitrile oxide, MNO) with 1a, b occurs on the exo-mthylene group from the exo-side, but on the endocyclic double bond in the case of 1c. The compound 2 undergoes the addition of MNO on both the exocyclic and endocyclic double bonds to give a corresponding bis-adduct. On the other hand, the reaction of phenyl azide (PA) with 1a–c occurs on the endocyclic double bond from the endo-side to give a single adduct. The reaction of 6-exo-methoxy-1,5,6-trimethyltricyclo[3.2.1.02,7]oct-3-en-8-one with MNO or PA was also studied to prove the regioselectivity of the cycloadditions of constrained vinylcyclopropane moiety.
Water Photolysis by Means of Visible Light with a System Composed of Prussian Blue and the Tris(2,2′-bipyridine)ruthenium(II) Complex
Authors: Kaneko Masao , Takabayashi Naoki , Yamauchi Yukio , Yamada Akira
Published: July 2006

A water-photolysis system composed of Prussian Blue (PB) and the tris(2,2′-bipyridine)ruthenium(II) complex([Ru(bpy)3]2+)which evolves hydrogen and oxygen simultaneously was studied. Both the components worked catalytically in the photolysis. PB provides active sites for both H2 and O2 evolution. The dependence on the pH showed optimum conditions at pH 2. The photolysis required the presence of a cation, and only such cations as K+ and Rb+ whose hydrated ions are smaller than the pore size of the PB lattice were active for the reaction. The dependene on the KCl concentraition showed an optimum point at 0.5 mol dm−3. The oxidative quenching of [Ru(bpy)3]2+* by PB was suggested, but its ratio in the total quenching process was estimated to be only 8.5%. The static quenching of [Ru(bpy)3]2+* by PB was demonstrated, and an interaction between the two components was shown by NMR spectroscopy. The effect of oxygen on the photolysis suggested that the reduction sites are located inside the PB lattice. A mechanism for the photolysis was proposed.
Thermal Behavior of Head-to-head Coumarin Dimers and Their Lactone-opened Derivatives
Authors: Yonezawa Noriyuki , Ikebe Yutaka , Yoshida Tsuyoshi , Hirai Teruhisa , Saigo Kazuhiko , Hasegawa Masaki
Published: July 2006

The thermal behavior of head-to-head coumarin dimers and twelve lactone-opened derivatives was investigated. Though the lactone rings in coumarin dimers are very susceptible to nucleophilic ring-opening, heating these derivatives reformed six-membered lactone rings except for certain imide and diamide derivatives. The large neiboring group effect allowed the relactonization by the attack of hydroxyphenyl group to carbonyl carbon in preference to the scission of cyclobutane ring.
The Thermal Isomerization of Azobenzenes. III. Substituent, Solvent, and Pressure Effects on the Thermal Isomerization of Push-pull Azobenzenes
Authors: Nishimura Norio , Kosako Shinya , Sueishi Yoshimi
Published: July 2006

The substituent, solvent, and pressure effects on the rate of the thermal cis-to-trans isomerization of 4-dimethylamino-4′-nitroazobenzene(NDAAB) derivatives have been studied. 2-Methyl- and 2′-chloro–NDAAB isomerize faster than NDAAB, and 2′-methyl- and 2-chloro-NDAAB isomerize slower than NDAAB. For 2,2′-dimethyl- and 2,2′-dichloro-NDAAB, the rates are between those of the monosubstituted ones. These findings are very similar to those for 4-(dimethylamino)azobenzene (DAAB) derivatives, and no fundamental difference in the kinetic-substituent effects was observed between NDAAB and DAAB. The volume of activation, which is of a negative value, varies remarkably from solvent to solvent and from substituent to substituent; its magnitude increases generally with an increase in the solvent polarity. Even for DAAB and 4,4′-bis(diethylamino)azobenzene (BDEAAB), the rate is appreciably accelerated by external pressures in polar solvents. It is concluded that the observed results are more consistent with the inversion mechanism than with the rotational mechanism.
A Versatile Synthesis of Four-, Five-, and Six-membered Cyclic Ketones Using Methyl Methylthiomethyl Sulfoxide
Authors: Ogura Katsuyuki , Yamashita Mitsuo , Suzuki Michiyo , Furukawa Shigeko , Tsuchihashi Gen-ichi
Published: July 2006

Cyclization of 1,n-dihalo[or bis(tosyloxy)]alkanes with methyl methylthiomethyl sulfoxide in the presence of a base (n-BuLi or KH) gave three-, four-, five-, and six-membered 1-methylsulfinyl-1-methylthiocycloalkanes. These cyclization products were easily converted to the corresponding ketones by acid hydrolysis except 1-methylsulfinyl-1-methylthiocyclopropane which afforded a complicated mixture. The combination of the cyclization with the acid hydrolysis thus provides a new method for synthesizing four-, five-, and six-membered cycloalkanones. Several representative preparations, such as those of substituted cyclobutanones, 3-cyclopentenone, and tetrahydro-4-pyrone, are described.
π-Electron Distribution in Benz[a]indeno[1,2,3-cd]azulene and the Corresponding Azepinium Ion
Authors: Murata Shigeru , Iwamura Hiizu
Published: July 2006

The π-electron density distribution in benz[a]indeno[1,2,3-cd]azulene and the corresponding azepinium ion has been calculated by the PPP MO method. The effects of the hetero atom and the benzo annellation on the π-electron density and bond order of the cyclopent[cd]azulene are discussed.
Excited-state Reactions of Coumarins in Aqueous Solutions. II. The Fluorescence Quenching of 7-Ethoxycoumarins by Halide Ions
Authors: Moriya Tetsuo
Published: July 2006

The fluorescence yield and the fluorescence lifetime of 7-ethoxycoumarins in aqueous solutions are reduced with the increase in the temperature and in the concentration of the quenching agents. The radiationless deactivation of the excited state in the absence of quenchers is temperature-dependent; its activation energy has been determined to be 32.5–34.8 kJ mol−1. The quenching reaction due to halide ions proceeds via both a diffusional and a static process. The rate constant for the diffusional process has a value of (9.7–10.2)×109 mol−1 dm3s−1 in the case of I− as a quencher. The static quenching component can be approximately described by the V[Q] expression, with the static quenching constant, V, being 1.6–1.8 mol−1 dm3. The quenching efficiencies that represent the probability leading to real quenching reactions by an encounter of the molecule and the halide ion are unity for I−, 0.39–0.42 for Br−, and almost zero for Cl−. The possible physical interpretation of the quenching mechanism is discussed in relation to the electron transfer between colliding species.
Carbon-13 Nuclear Magnetic Relaxation Studies of Benzene Molecules Adsorbed on the Pillar Interlayered Montmorillonite
Authors: Matsumoto Mutsuyoshi , Shinoda Sumio , Takahashi Hiroshi , Saito Yasukazu
Published: July 2006

Carbon-13 nuclear magnetic relaxation times of 13C-enriched benzene have been determined in order to elucidate the adsorption properties of PILM (pillar interlayered montmorillonite) by varying temperatures and coverages. The activation energy of diffusion as small as 6.5 kJ mol−1 indicates that the majority of PILM adsorption sites exhibits a weak interaction with benzene. The pre-exponential factor of correlation time was exceptionally large, probably because the two-dimensional pore structure of PILM, in contrast to the three-dimentional zeolite or the open surfaces of graphitized carbon black and silica gel, restricts the chance for the adsorbate to diffuse. In the spin-lattice relaxation spectra at low temperatures, the internal and the external surfaces of PILM were discriminated, since the two adsorbed states on these surfaces give different T1 and chemical shift values.
Comparison of the Experimental Zone Mobility-pH Curves of the Bases of Nucleic Acid on the Pure Cellulose Paper with the Calculated Ones
Authors: Kitaoka Yoshinori
Published: July 2006

Comparison of the experimental zone mobility-pH curves of nucleic acid bases with the calculated ones was made over acidic and basic regions using a pure cellulose paper as a support after correction of the capillary action and the endoosmotic flow. The mobilities in the acid region agreed with the calculated ones but those in the basic region did not. Some unknown factors affect the mobilities in the basic region.
Restricted Rotation Involving the Tetrahedral Carbon. LIV. The Effects of 1-Substituents on the Barriers to Rotation in 9-(2-Methyl-1-naphthyl)fluorenes
Authors: Murata Shigeru , Mori Teruo , Oki Michinori
Published: July 2006

A series of 1-substituted 9-(2-methyl-1-naphthyl)fluorenes, where the substituent is fluoro, chloro, bromo, or methyl, has been prepared and barriers to rotation in these compounds have been examined to investigate the substituent effects. The barrier is enhanced generally, if we go from the 1-substituent of a small size to that of a large size with an exception of the fluorine case: the 1-fluoro compound exhibits a lower barrier to rotation than the unsubstituted compound by ca. 0.5 kcal mol−1. X-Ray crystallographic analysis suggests that, in the fluoro compound, the C9(fluorene)-to-C1(naphthalene) bond is abnormally long, although other compounds possess bonds of normal lengths. The low barrier to rotation in the fluoro compound relative to the unsubstituted is thus attributed to the raise of the ground state energy and insufficient raise of the transition state energy in the former compound.
Crystal and Molecular Structure of 3,8-Di-t-butyl-5,6-diphenyl-1-thioxo-2,9-dithia-1-phosphabicyclo[4.3.0]nona-3,7-diene
Authors: Uchida Tokiko , Kozawa Kozo , Saito Takao , Motoki Shinichi
Published: July 2006

The crystal and molecular structures of the title compound were determined by means of X-ray diffraction. Crystal data: C26H31S3P, Mr=470.68, orthorhombic, a=17.116(4), b=19.798(4), c=14.898(3) Å, V=5048.4 Å3 (21 °C), space group Pbca, Dm=1.23, Dx=1.239 g cm−3, Z=8, μ=3.58 cm−1 (Mo Kα). The structure was solved by the direct method and refined by the full-matrix least-squares method to R=0.083 for 3318 observed reflections. The bicyclo skeleton is so highly strained that abnormal bond distances [P–C of 1.895(5) and C–C of 1.594(6) Å] were observed. Conformation of six-membered ring is a boat-form.
Shinjulactones G and H, New Bitter Principles of Ailanthus altissima Swingle
Authors: Ishibashi Masami , Yoshimura Shin , Tsuyuki Takahiko , Takahashi Takeyoshi , Matsushita Kazuhiro
Published: July 2006

Two bitter quassinoids, shinjulactones G and H were isolated from Ailanthus altissima  Swingle and their structures were determined to be 1β,11β,12α,20-tetrahydroxypicras-3-ene-2,16-dione and 2α,12β-dihydroxypicrasane-1,11,16-trione, respectively, by spectral and chemical means.
Interionic Charge Transfer Enhanced by Hydrophobic Interaction
Authors: Hirano Koichi , Tokuhara Masahiko
Published: July 2006

A water solution containing Rhodamine 6G and Na-tetraphenylborate exhbits a new absorption band at 540 nm, which has the characteristics of a charge-transfer (CT) band. In organic solvents, however, such a CT band is not found. This indicates that hydrophobic interactions enhance the charge transfer interaction.
Dependence of Efficiency of Photoinduced Electron Transfer from Pyrene to Copper(II) Ion on Copper(II)-Ion Fraction on Dodecyl-Sulfate-Micelle Surface
Authors: Nakamura Takashi , Kira Akira , Imamura Masashi
Published: July 2006

In quenching of the pyrene fluorescence by copper(II) ions in dodecyl sulfate micelles whose surface is covered by sodium and copper(II) ions, the pyrene-cation quantum yield decreases, after reaching a certain maximum yield, with increasing copper(II)-ion fraction. The decrease suggests that the micellar structure becomes unfavorable for electron transfer quenching as copper(II) ions displace sodium ions on the micellar surface.
Adsorption Measurements during Catalytic Isomerization of Pentenes and 2-Methyl-1-pentene over KC24
Authors: Tsuchiya Susumu , Yamamoto Shinji , Imamura Hayao
Published: July 2006

The catalytic isomerization of pentenes over KC24 has been investigated. The double-bond-migration and the cis-trans isomerization took place over KC24, but the skeletal isomerization was not observed. From the rates of reactions and the selectivity ratios, all six of the relative rate constants and the activation energies of reactions were determined. The reaction paths on the triangular graph calculated from the rate constants show the cis-convex type profile. The competitive isomerization of 1-pentene and 2-methyl-1-pentene has also been investigated. The rate of isomerization of 1-pentene was greater than that of 2-methyl-1-pentene, which can be explained on the basis that the amount of chemisorption of 1-pentene during the competitive reaction is greater than that of 2-methyl-1-pentene.
The Oxidation of Iron(II) Sulfate with Sulfur Dioxide and Oxygen Mixtures
Authors: Sato Tsugio , Goto Takashi , Okabe Taijiro , Lawson Frank
Published: July 2006

The oxidation of iron(II) sulfate with SO2/O2 (sulfur dioxide and oxygen mixtures) was carried out using an air-lift percolator in the temperature range of 25–50 °C and over the pH range of 0–3. Under conditions in which sulfur dioxide is immediately oxidized, the rate of the oxidation of iron(II) is proportional to the flow rate of sulfur dioxide and independent of the flow rate and partial pressure of oxygen, and the concentration of iron(II). The molar ratio of Fe2+ oxidized/SO2 oxidized is 1.3–2 in the pH range of 0.5–2.0. A free-radical chain reaction in which HSO5− oxidizes iron(II) is proposed as the reaction mechanism.
The Synthesis and Thermal Decomposition of Magnesium Phosphoramidate
Authors: Watanabe Makoto , Morii Yoshio , Sato Shoji
Published: July 2006

Magnesium phosphoramidate–water (1/7) was made by adding an aqueous magnesium chloride solution to an aqueous potassium hydrogenphosphoramidate solution at pH 9.0–9.5. The product was stable at room temperature, while it decomposed on heating. The product decomposed to produce polyphosphates when it was heated in air. The decomposition product heated above 600 °C was magnesium diphosphate. A small amount of imidodiphosphate was made when the phosphoramidate was heated in dried N2.
Photochemistry of Dihalogenobis(diamine)chromium(III) Complexes in Methanol
Authors: Sawano Masanori , Yoshifuji Hideki , Uehara Akira , Tsuchiya Ryokichi
Published: July 2006

The photochemical reactions of trans- and cis-[CrX2(AA)2]X in methanol were investigated under the ligand-field band irradiation, where X is Cl− or Br− ion and AA is en, pn or tn. In the earlier step of irradiation, only trans-to-cis photoisomerization was observed irrespective of diamines. The process of the photoisomerization was reasonably explained in terms of the bond indices calculated on the basis of VC theory. The quantum yields for dichloro complexes were larger than those for dibromo complexes, and the yields increased in the order of pn<en<tn complexes. The photochemistry of cis-[CrCl2(pn)2]Cl was also studied and the difference of the photochemical reactions from the thermochemical reactions was discussed.
The Changes in Conformation and Complexability of 6,6′-Diamino-2,2′-bipyridine by Protonation
Authors: Kishii Noriyuki , Araki Koji , Shiraishi Shinsaku
Published: July 2006

The reaction of 6,6′-dibromo-2,2′-bipyridine with ammonia in an autoclave gave 6,6′-diamino-2,2′-bipyridine (DABP) in more than 80% yields. DABP behaved as a diacidic base in the pH range of 0 to 10 with the conformational changes. DABP formed complexes with Cu(II), Ni(II), Co(II), and Zn(II). The amino groups at 6 and 6′ positions play a role as strong electron-donationg groups and not as coordination sites. pKa values and complex formation constants were estimated.
The Reaction of Butadienylphosphonates with a Oxosulfonium Ylide, Phosphonium Ylides, and Ketone Enolates
Authors: Minami Toru , Yamanouchi Takenobu , Tokumasu Shigehumi , Hirao Ichiro
Published: July 2006

The condensation of diethyl (ethoxycarbonylmethyl)phosphonate (1a) with cinnamaldehyde in the presence of piperidine gave a 1:1 mixture of diethyl (1E,3E)- (2a) and (1Z,3E)-(1-ethoxycarbonyl-4-phenyl-1,3-butadienyl)phosphonates (2b) in 82% yield, while a similar reaction using diethyl [cyanomethyl- (1b) and methylsulfonylmethyljphosphonates (1c) exclusively gave diethyl (1E,3E)-[1-cyano- (3) and 1-methyl-sulfonyl-4-phenyl-1,3-butadienyl]phosphonates (4) in 78% and 93% yields, respectively. The reaction of the butadienylphosphonates 2–4 with dimethyloxosulfonium methylide (5) gave mixtures of (E)- and (Z)-(1-substituted 2-styrylcyclopropyl)phosphonates 7–9 in good yields. Similar treatment of the butadienylphosphonate 2 with phosphonium ylides 16a–c led to (3-substituted 1-ethoxycarbonyl-2-styrylcyclopropyl)phosphonates 17a–c in moderate yields. Reduction and oxidation of 7 were studied. The reaction of the phosphonates, 2 and 4, with ketone enolates and ketones resulted in the formation of unexpected olefins 22–24 and dienes 20a, b. The reaction mechanism is discussed.
Redox-Switched Crown Ethers. 1. Redox-Coupled Control of Metal-Ionophore Interactions and Their Application to Membrane Transport
Authors: Shinkai Seiji , Inuzuka Kenichi , Hara Kenzo , Sone Takaaki , Manabe Osamu
Published: July 2006

Polyether ionophores with redox-functional thiol groups were synthesized: they are a diaza-18-crown-6 with a disulfide cap that exhibits redox-responsive interconversion between crown(1red) and cryptand(1ox) and tri- and tetra(oxyethylene)s having a mercapto and an 8-quinolyl group as their terminal groups that feature redox-responsive interconversion between monopodands (2red) and dipodands (2ox). For Na+  1red and 1ox showed a similar ion affinity, but 1ox bound K+, Rb+, and Cs+ more efficiently than 1red because of the coordination of the cap oxygens to the complexed metal cations. The difference was rationalized by such that “K+ Rb+ and Cs+ also) perches on the crown ring whereas Na+ nests in it,” 2ox showed, in most cases, the ion affinity significantly higher than corresponding 2red, indicating the cooperative action of the two poly(oxyethylene) chains on the ion-binding. The rate of K+ transport with 2red across a liquid membrane was very slow but 2ox carried K+ more efficiently. It was found that the rate of K+ transport started with is efficiently accelerated by the addition of I2. This is due to the redox-switch of the carrier from 2red to 2ox. These results suggest that the redox-functionalized ionophores provide novel applications of ion-extraction and ion-transport.
Mixed Chelates of Cadmium(II) with N-(2-Hydroxyethyl)ethylenediamine and Some Amino Acids
Authors: Chandel Chandra Pal Singh , Gupta Chand Mal
Published: July 2006

An extended method of Schaap and McMasters has been applied for the study of mixed-ligand complexes of Cadmium(II) with N-(2-hydroxyethyl) ethylenediamine (heda) and some amino acids polarographically at DME. The reduction of mixed-ligand complex at DME has been found to be reversible, and diffusion controlled at temp (30±0.5)°C and μ=1.0 M(KNO3). The formation of MXY, MXY2, and MX2Y has been used to discuss the non-existence of MX3 complexes, where X has been used for heda and Y for amino acids. The values of stability constants β01, β02, β03, β11, β12, and β21 are 3.90, 6.80, 8.94, 8.85, 11.00, and 12.13 for Cd–heda–isoleucinate system, 4.30, 7.70, 9.80, 9.36, 11.75, and 12.42 for Cd–heda–glycinate system, 3.95, 6.81, 8.90, 8.35, 10.99, and 12.12 for Cd–heda–valinate system, 4.10, 7.10, 9.08, 9.02, 11.20, and 12.18 for Cd–heda–serinate system, 4.48, 8.02, 10.33, 9.55, 12.00, and 12.59 for Cd–heda–glutamate system, 4.24, 7.54, 9.54, 9.26, 11.62, and 12.33 for Cd–heda–alaninate system and 4.06, 7.06, 9.02, 9.00, 11.16, and 12.20 for Cd–heda–threoninate system respectively.
Study of the Polymerization of Silicic Acid Adsorbed on Iron(III) Hydroxide by Trimethylsilylation-Gas Chromatography
Authors: Yokoyama Takushi , Shimono Tsugio , Tarutani Toshikazu
Published: July 2006

Polymerization of silicic acid adsorbed on iron (III) hydroxide from dilute monosilicic acid solutions in the concentration range 5–40ppm (SiO2) was studied over the pH range 6–12. Silicic acid species formed on the hydroxide were trimethylsilylated and trimethylsilyl derivatives were detected by gas chromatography. Monosilicic acid adsorbed polymerized, and dimer (Si2O76−), linear trimer (Si2O108−) and tetramer (Si4O1310−), and cyclic tetramer (Si4O128−) were found as polymeric species.
Preparation of Tetraalkyl 2,2′-Phthaloylbis[1,2-dihydro-1-isoquinolylphosphonate]s and their Reactions with Base
Authors: Akiba Kin-ya , Negishi Yoshio , Inamoto Naoki
Published: July 2006

The titled compounds were prepared and the reaction with lithium diisopropylamide followed by quenching with alcohol gave isoquinoline, 13-alkoxy-8H-dibenzo[a,g]quinolizin-8-ones, and dialkyl 2-(o-alkoxycarbonylbenzoyl)-1,2-dihydro-1-isoquinolylphosphonates.
The Crystal and Molecular Structure of Quadrivalent Osmium Porphyrin; μ-Oxo-bis[methoxo(octaethylporphinato)osmium(IV)]
Authors: Masuda Hideki , Taga Tooru , Osaki Kenji , Sugimoto Hiroshi , Mori Masayasu
Published: July 2006

The crystal structure of the title complex has been determined by the X-ray method. The complex crystallizes in the monoclinic space group P2/c with a=24.171(9), b=14.037(3), c=24.401(9) Å, β=119.68(9)°, and Z=4. The structure was solved by the heavy-atom method and refined to R=0.094 for 3838 reflections. Two independent dimers exist with a crystallographically imposed two-fold axis in the unit cell. The two dimers are in an approximately orthogonal arrangement, and they take very similar conformations. The noticeable structural parameters are the average distances of 2.033(28) Å for OsIV–N, 1.808(3) Å for OsIV–O2−, and 1.997(29) Å for OsIV–OCH3. The two porphinato cores bridged by a μ-oxo oxygen atom rotate around the approximately linear Os–O–Os bond (the average valence angle=178°) by 23(1)° from the eclipsed form. The porphine ring is planar within 0.10 Å, and deviation of the Os atom from the porphinato plane of the four nitrogen atoms is 0.06 Å. These results were compared, in the relation of the specific physicochemical properties in solution, with those of the corresponding RuIV complexes reported previously.
Liquid Crystal Formation in Binary Systems. X. Potentially Smectogenic Behavior of Some p-Disubstituted Benzenes
Authors: Chino Eiji , Matsunaga Yoshio , Suzuki Mika
Published: July 2006

Studies on binary systems with nematogenic N-(4-propoxybenzylidene)-4-hexylaniline revealed that 4-nitrophenyl alkanoates, alkyl 4-nitrobenzoates, N-(4-nitrophenyl)alkanamides, and N-alkyl-4-nitrobenzamides are potentially smectogenic. When the Schiff base is mixed separately with a homologous member from 4-nitrophenyl decanoate to tetradecanoate, a stable smectic A phase is induced and its maximum temperature is about 48 °C. The estimated latent transition points to this mesophase of these benzene derivatives are in the range from −25 to 10 °C. On the other hand, only metastable smectic A phases can be produced with hexyl to dodecyl 4-nitrobenzoates, the maximum temperatures being from 15 to 26 °C. While the metastable smectic B phase of the Schiff base is to some extent stabilized by the addition of the alkanoates, it is drastically depressed by the benzoates. The addition of N-(4-nitrophenyl)nonanamide to -dodecanamide produces a stable smectic A phase and also stabilizes the metastable smectic B phase. No smectic A phase is found in mixtures of the Schiff base with N-octyl- to N-dodecyl-4-nitrobenzamides, and the isotropic or nematic-smectic B transition point curves are almost horizontal indicating that these benzene derivatives have transitions to latent smectic B phases between 10 and 20 °C. Results obtained with some related compounds are also presented.
The Micellar Properties of 1-Dodecylpyridinium Chloride as Studied by the Ion-selective Electrodes
Authors: Maeda Tamaki , Satake Iwao
Published: July 2006

The surfactant ion and counterion activities of aqueous 1-dodecylpyridinium chloride with and without KCl were determined by using ion-selective electrodes. In the concentration range above the critical micelle concentration (cmc), the surfactant ion activity (a+) was found to decrease gradually with increasing surfactant concentrations, while the reverse change was found for the counterion activity (a−). As a result, the mean activity increased slightly but regularly with increasing concentrations. The concentration dependences of a+ and a− became progressively smaller as the salt concentration increased. An application of the charged phase separation model led to an apparent degree of counterion association to the micelle (β) of 0.70 regardless of the salt concentration. On the basis of these observations, the estimations were made for the concentration of monomeric surfactant ion (C+) and the activity coefficients of counterion (γ−) and surfactant ion (γ+) above the cmc. The values of C+ and γ+ decreased appreciably, while that of γ− increased with increasing concentrations. The value of β was also estimated from the concentration dependence of a− and the validity of this method was discussed.
The Thermal Properties of Liquid Crystalline Materials Incorporating Cyanothiophene and Cyanofuran
Authors: Miyake Shiro , Kusabayashi Shigekazu , Takenaka Shunsuke
Published: July 2006

Some homologous series of cyanothiophene and cyanofuran compounds have been prepared. 4-Alkoxyphenyl 3-(5-bromo-2-thienyl)acrylate (1) and 4-alkoxyphenyl 3-(5-cyano-2-thienyl)acrylate (2), and 4-alkoxy-phenyl 4-(5-bromo-2-furylcarbonyloxy)benzoate (3) and 4-alkoxyphenyl 4-(5-cyano-2-furylcarbonyloxy)benzoate (4) give rise to a nematic phase. For compound 4, a smectic A phase which commences from the hexyloxy homolog has a bilayer (SA2) arrangement of the molecules. The thermal stabilities of the mesophases are lower than those of the corresponding benzonitrile compounds. This arises from an increased molecular breadth around the terminal portion and the change of the dipole moment arising from the terminal cyano group bending with respect to the long molecular axis.
The Transformation of γ-FeO(OH) to Fe3O4 and Green Rust II in an Aqueous Solution
Authors: Tamaura Yutaka , Saturno Mervelina , Yamada Kaoru , Katsura Takashi
Published: July 2006

A mechanism of the transformation of γ-FeO(OH) to Fe3O4 and/or green rust II in an aqueous solution containing FeII ion in the presence or absence of the SO42− ion at 298 K is described. γ-FeO(OH) is dissolved by two mols of FeII ions adsorbed on the surface of γ-FeO(OH), and a dissolved species (DS) is formed, which is then transformed to Fe3O4 or green rust II. The equilibrium of the formation of green rust II from γ-FeO(OH) is represented by:

K=[H+]2⁄(Kh2[Fe2+]2[SO42−]) K=2.14×108,

where Kh is the hydrolysis constant of Fe2+. This equation shows that, for a given proton concentration(pH), higher concentrations of Fe2+ and SO42− ions facilitate the formation of green rust II from γ-FeO(OH). When little green rust II is formed, the DS is transformed to Fe3O4.
Structure Determination of Bitter Principles of Ailanthus altissima. Structures of Shinjulactones B, D, and E
Authors: Furuno Tetsuo , Ishibashi Masami , Naora Hirokazu , Murae Tatsushi , Hirota Hiroshi , Tsuyuki Takahiko , Takahashi Takeyoshi , Itai Akiko , Iitaka Yoichi
Published: July 2006

Bitter quassinoids, shinjulactones B, D, and E were isolated from Ailanthus altissima  Swingle. Shinjulactone B is the first example of natural bitter principles with a 1,2-seco-1-nor-6(5→10)abeo-picrasane skeleton and shinjulactones D and E are a hexahydro derivative and a 6α-hydroxy derivative of ailanthone, respectively.
Hydrolysis of N-Salicylidene-2-methoxyethylamine. Intramolecular General Base Catalysis and Specific Effects of Boric Acid
Authors: Nagamatsu Hiroaki , Okuyama Tadashi , Fueno Takayuki
Published: July 2006

Hydrolysis of N-salicylidene-2-methoxyethylamine is kinetically investigated at 30 °C. Intramolecular general base catalysis by the o-O− substituent takes place in the neutral pH region. Nucleophilic catalysis by morpholine was also found to be operative. Added boric acid accelerates the hydrolysis above pH 5.5 while it decelerates the hydrolysis below pH 5.5. The hydrolysis rate as the function of the boric acid concentration follows a saturation curve in harmony with a reaction sequence involving a rapid equilibrium formation of a borate-substrate complex followed by its breakdown. The morpholine catalysis is inhibited by boric acid in accord with the slow reaction of morpholine with the complex. The water reaction of the complex is considered to involve a rearrangement of the complex and an intramolecular transfer of the boron-coordinated hydroxide ion to the iminium carbon.
Effects of Boric Acid on the Rate and Equilibrium of Schiff Base Formation from Salicylaldehyde
Authors: Nagamatsu Hiroaki , Okuyama Tadashi , Fueno Takayuki
Published: July 2006

Effects of boric acid on the formation of the Schiff base from salicylaldehyde and 2-methoxyethylamine (or glycinate) were examined in aqueous solution. From the formation constants in the absence and presence of boric acid, the equilibrium constants for the borate-Schiff base complexation were determined. The structure of the complex was deduced from the UV spectral analysis. Formation of the Schiff base was found to be accelerated by boric acid (pH 7–10). A mechanism for the reaction involving the complex is presented.
Oxidative Carbonylation of Piperidine in the Presence of Palladium(II)–Copper(II) Catalytic System
Authors: Sheludyakov Yuri L , Golodov Valentin A
Published: July 2006

A kinetic study on oxidative carbonylation of piperidine to give 1,1′-carbonyldipiperidine in the presence of Pd(II) and Cu(II) complexes at 40 °C has been investigated.
On the Physicomagnetic Properties of Some Nitro Compounds
Authors: Abdel-Kader Mohamed M , Salem Safia M
Published: July 2006

The mean molar susceptibilities of nine aromatic nitro compounds namely, o-, m-, p-dinitrobenzene; o-, m-, p-nitrobenzoic acid and o-, m-, p-nitrophenol have been measured. The semiexperimental anisotropies of these molecules have been calculated. The magnetic data are correlated with the positional isomerism of the nitro groups and the crystal structures of these molecules as well as their hydrogen bonding.
Vibrational Spectra and Thermodynamic Functions of 2-Methoxypyridine and 2-Methoxy-d3-pyridine
Authors: Medhi Kanak C
Published: July 2006

The infrared spectra in the liquid state (4000–50 cm−1) and in the vapor phase (4000–400 cm−1) and the polarized laser Raman spectra in the liquid state have been measured for 2-methoxypyridine and 2-methoxy-d3-pyridine. Essentially complete assignments of the observed frequencies are presented. Ideal gas state thermodynamic functions of the molecules are also calculated in the temperature range 200–1500 K.
Aryliminodimagnesium Reagents. VII. The Moderate Electron-donating Ability Estimated by Oxidation Peak Potentials
Authors: Okubo Masao , Tsutsumi Toshiki , Ichimura Akio , Kitagawa Toyokichi
Published: July 2006

Oxidation peak potentials of p-RC6H4N(MgBr)2 and p-RC6H4MgBr (R=CH3O, CH3, F) were determined by cyclic voltammetry with a platinum disk electrode in tetrahydrofuran. The potentials obtained proved to be a semiquantitative measure of electron-donating abilities of organomagnesium reagents.
Characteristic Transport Properties of Diaza-crown Ethers for Primary and Secondary Ammonium Cations
Authors: Tsukube Hiroshi
Published: July 2006

Simple lipophilic diaza-crown ethers show unique transport properties for primary and secondary ammonium salts, which are markedly different from those observed with common crown ether systems.
A Convenient Procedure for Iodination of Electron-rich Aromatic Compounds using Iodine–Copper(II) Acetate
Authors: Horiuchi C Akira , Satoh J Yasuo
Published: July 2006

The iodination of some electron-rich aromatic compounds, namely, three polymethylbenzenes, aniline, phenol, anisole, and phenetole, using iodine–copper(II) acetate in acetic acid, afforded the corresponding iodo compound in high yield.
The Bridging Tridentate-type Carboxylato Ligand in Isomorphous Guanidinium Di(μ-acetato)bis(triacetatoaqualanthanoidates(III)), [(NH2)3C]2-[M2(CH3CO2)8(H2O)2], (M=La, Ce, Pr, Nd, and Sm)
Authors: Sawase Hiroshi , Koizumi Yukio , Suzuki Yasuo , Shimoi Mamoru , Ouchi Akira
Published: July 2006

The M–O bond lengths and some bond angles of the acetato ligands in the title compounds were compared with each other using their structural data as obtained by the single-crystal X-ray diffraction method. With the increase in the atomic number of the central metal atom, the length of the weakest M–O bond in the bridge increases, even though all the other M–O bonds are shortened. This fact can be explained as follows: as the number of ligating oxygen atoms around the central metal atom is almost at a maximum in these complexes, the sharing space of the tenth coordinating atom on the coordination sphere decreases when the radius of the central metal atom is shortened as a result of the lanthanoid contraction effect.
Photoresponsive Crown Ethers. 13. Synthesis of Photoresponsive NS2O Crown Ethers and Application of the Cu(I) Complexes to O2-Binding
Authors: Shinkai Seiji , Shigematsu Kazuyoshi , Honda Yoshihiro , Manabe Osamu
Published: July 2006

Photoresponsive crown ethers with heavy metal affinity were synthesized: They are the NS2O crowns bound to photofunctional azobenzene at 4,4′-positions via X(CH2 or CO) (1(X=CH2) and 1(X CO), respectively). They efficiently extracted heavy metal ions from aqueous phase to organic(dichloromethane) phase. The continuous variation method established that both trans-1 and photoisomerized cis-1 bind two Cu(II) ions forming 1:1 metal/NS2O crown complexes. The trans-1(X=CH2)·Cu(I)2 complex was irreversibly oxidized by O2 to the Cu(II)2 complex, whereas the cis-1(X=CH2)·Cu(I)2 complex bound O2 in a partly reversible manner like Osborn’s complex. Thus, a photoinduced change in the Cu(I)·····Cu(I) interatomic distance is responsible for the stability of the O2 complex. These results show that the extraction of heavy metal ions and the O2-complexation can be controlled by light with the mediation of photoresponsive NS2O crown ethers.
The Magnetic Properties of Cu(CH3COO)2·2NH4Cl and NH4Cu(HCOO)Cl2
Authors: Emori Shuji , Muto Yoneichiro
Published: July 2006

The temperature dependence of the magnetic susceptibility of Cu(CH3COO)2·2NH4Cl obeys the Bleaney-Bowers equation, indicating the existence of the anionic copper(II) acetate dinuclear unit. The exchange integral, J/k, is equal to −205 K. For NH4Cu(HCOO)Cl2, the structure containing copper(II) formate layers connected by tetrachlorocuprate(II) bridges is presumed on the basis of the value of the Weiss constant.
The Radiopolarography of Gadolinium, Ytterbium, and Californium
Authors: Shiokawa Yoshinobu , Suzuki Shin
Published: July 2006

The polarographic reduction of Gd, Yb, and Cf was investigated. It was found that the M(III)→Hg(M) reduction process in an aqueous solution, that cannot be detected by dc polarography, can be detected by radiopolarography. The polarographic behavior of Gd, Eu, Yb, and Cf in the presence of 1,4,7,10,13,16-hexaoxacyclooctadecane(18-crown-6) suggests that Cf(III) is reduced in two steps to Hg(Cf) in an aqueous solution.
Phenanthraquinone Monothiosemicarbazone as Sensitive Reagent for the Spectrophotometric Determination of Zinc(II)
Authors: Sinha Prem Prakash , Sindhwani Sharwan Kumar , Singh Rajendra Pal
Published: July 2006

Phenanthraquinone monothiosemicarbazone has been found to be a sensitive and selective reagent for the spectrophotometric determination of zinc(II) in the pH range 7.0–8.6. The red complex formed shows maximal absorbance at 510 nm. Beer’s law is obeyed up to 1.96 ppm and optimum range of concentration being 0.22–1.70 ppm. The sandell sensitivity is 0.0018 μg ZnII cm−2, with molar extinction coefficient being 3.52×104 mol−1 cm−1. The method has been applied to the determination of zinc in 6% Zn-Al alloy.
The Cooperative Binding Isotherms of Sodium Alkanesulfonates to Poly(1-methyl-4-vinylpyridinium chloride)
Authors: Satake Iwao , Hayakawa Katumitu , Komaki Mayumi , Maeda Tamaki
Published: July 2006

Binding isotherms of nonane-, decane-, and undecane- sulfonate ions to poly (1-methyl-4-vinylpyridinium chloride) were determined by using nitrobenzene-membrane electrode. It was shown that an increase in alkyl chain length is accompanied not only by a rapid increase in the cooperativity parameter but by a regular decrease in an equilibrium surfactant concentration at half binding.
A Modification of the Method of Spectrophotometric Determination of Iron with Ethylenediamine-N,N′-bis(2-hydroxyphenylacetic acid)
Authors: Katsuyama Tetsuo , Watanabe Kyoko
Published: July 2006

Etylenediamine-N,N′-bis(2-hydroxyphenylacetic acid) (H4eddha) reacts with iron to form a 1:1 complex having an absorption maximum at 480 nm. The method of the spectrophotometric determination of iron with eddha was modified by heating the colored solution in a boiling water bath for a few minutes. The molar absorption coefficient of the FemIII-eddha complex formed was 4.72×103 1 mol−1 cm−1 and the relative standard deviation for determination of 5.90×10−5 mol dm−3 (3.29 μg cm−3) of iron was 0.21%. The effect of 45 diverse ions was examined; only a few metal ions interfered. Aluminium alloys were analyzed for iron by the present method.
Synthesis and Reactions of 1-(Trimethylsilyl)allyl Chloride
Authors: Shimizu Nobujiro , Shibata Fumihiro , Tsuno Yuho
Published: July 2006

1-(Trimethylsilyl)allyl chloride prepared conveniently from 1,3-dichloropropene reacted smoothly with organocopper compounds yielding terminal alkenylsilanes, while its Grignard reactions with carbonyl compounds gave the corresponding alcohols with the regioselection depending sensitively on substrates.
Electronic Spectra of Cyclotrisilane (Si3) and Disilene (Si=Si) Frameworks
Authors: Watanabe Hamao , Kougo Yuichi , Kato Motohiko , Kuwabara Haruyoshi , Okawa Tadashi , Nagai Yoichiro
Published: July 2006

Photolyses of a series of octaalkylcyclotetrasilanes (1) in a hydrocarbon solvent successively afforded hexaalkylcyclotrisilanes (2) and tetraalkyldisilenes (3). Compounds 2 and 3 were found to exhibit their absorption bands corresponding to the lowest energy transitions at λmax 300–330 and 390–440 nm, respectively.
Monodebromination of gem-Dibromocyclopropanes by Sodium Hydrogentelluride
Authors: Osuka Atsuhiro , Takechi Keita , Suzuki Hitomi
Published: July 2006

gem-Dibromocyclopropanes were effectively reduced to monobromocyclopropanes by sodium hydrogentelluride.