bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Effects in the Reactions of Diazoalkanes with 2,3-Dichloro-5,6-dicyanobenzoquinone
Authors: Oshima Takumi , Nagai Toshikazu
Published: July 2006

2,3-Dichloro-5,6-dicyanobenzoquinone (DDQ) reacted with diazoethane to give stereoisomeric bicyclic diones (3, isomer ratio=3.4) arising from dipolar addition to the C=C bond of DDQ. DDQ reacted with phenyldiazomethane to afford also stereoisomeric bicyclic diones (7) in the ratio of 5:1, together with stilbenes (8). On the other hand, DDQ gave the (ethenyloxy)benzene derivative (14) with 1-phenyldiazoethane. The formation of 8 and 14 was interpreted by considering the participation of 1:1 betaines resulting from addition to the C=O bond. The added methanol captures the betaines, thus giving rise to dimethyl acetals of benzaldehyde and acetophenone, along with 2,3-dichloro-5,6-dicyanohydroquinone. These reactivities of DDQ were discussed in comparison with those of chloranil.
Synthetic Studies of Diels–Alder Adduct of Furan. Formal Total Synthesis of (±)-Avenaciolide
Authors: Kotsuki Hiyoshizo , Ohnishi Hiroyuki , Akitomo Yasuhiro , Ochi Masamitsu
Published: July 2006

The endo-Diels–Alder adduct of furan with methyl acrylate was transformed into a bis-γ-lactone derivative which is a well-known precursor for the synthesis of (±)-avenaciolide. The route involves 13 steps and the overall yield was 17.9%.
Syntheses of (−)-8-epi-Swainsonine and (−)-1,8-Di-epi-swainsonine, Stereoisomers of Physiologically Interesting Indolizidine Alkaloid, Swainsonine
Authors: Tadano Kin-ichi , Iimura Youichi , Hotta Yukinori , Fukabori Chiyoko , Suami Tetsuo
Published: July 2006

Two stereoisomers of the indolizidine alkaloid swainsonine, (−)-8-epi-swainsonine (2) and (−)-1,8-di-epi-swainsonine (3), have been synthesized from the known methyl 3-acetamido-2-O-acetyl-4,6-O-benzylidene-3-deoxy-α-d-glucopyranoside and methyl 3-acetamido-2-O-acetyl-3-deoxy-4,6-di-O-mesyl-α-d-glucopyranoside (14), respectively. The key pyrrolidine ring formation was achieved by intramolecular cyclization of a 6-O-tosyl derivative or a di-O-mesyl derivative 14 efficiently. The α-mannosidase inhibitory activity of the synthetic 2 and 3 was also evaluated.
Chemical Reactivities of Coordinatively Unsaturated Hydridotris(phosphonite)cobalt(I) Species Photogenerated towards Allylic and Related Compounds
Authors: Onishi Masayoshi , Oishi Shigero , Sakaguchi Mitoshi , Takaki Isato , Hiraki Katsuma
Published: July 2006

Pyrex-filtered photoirradiation with a high-pressure Hg lamp was performed for a thermally inert hydridocobalt(I) CoH[PPh(OEt)2]4 in the presence of some allylic compounds. Allyl benzoate and allyl phenyl ether showed the cleavage of allylic-O bonds to give propene in a stoichiometric quantity to the complex charged. Photoassisted catalytic double-bond migration occurred for N-allylacetamide, N,N-diethylallylamine, and allylbenzene to afford the respective (E)- and (Z)-1-propenyl derivatives with kinetically controlled E, Z compositions, and the fractions of Z isomers at the initial stage of the reaction proceeding were near 79, 30, and 20%, respectively. Laser flash photolysis study revealed that the double-bond migration was initiated by the coordination of the substrates through C=C double bond rather than nitrogen or oxygen donor-atom to the coordinatively unsaturated species “CoH[PPh(OEt)2]3” photogenerated.
Titanium Determination under High-Sensitivity Conditions with 2-(5-Chloro-2-pyridylazo)-5-dimethylaminophenol. I
Authors: Marini Héctor Jose , Antón Rosa Isabel , Boeris Maria Susana , Olsina Roberto Antonio
Published: July 2006

The optimum working conditions for the complexing reactions between Ti(IV) and 2-(5-chloro-2-pyridylazo)-5-dimethylaminophenol (5.ClDMPAP) in aqueous alcoholic solutions were studied. When an ethanol solution of 5.ClDMPAP is added to a Ti(IV) aqueous solution, complex species, whose spectral and stoichiometric characteristics depend on pH, develop rapidly. The complex selected for the analytical work forms between pH 4.7 and 5.8 and has a 3:1 ligand-metal molar ratio. The complex fulfils Beer’s law up to a Ti(IV) concentration of 0.7 ppm, working at λmax=580 nm. The optimum concentration range (Ringbom) was between 0.05 and 0.7 ppm of Ti(IV). The molar absorptivity at λmax=580 nm and Sandell index are 4.39×104 dm3 mol−1 cm−1 and 0.0011 μg cm−2, respectively. An absorptiometric method to determine Ti(IV) was developed and the proper ways to reduce interferences produced by some anions and cations are described. The method developed was applied to Ti(IV) determination in optical glass and ceramic materials.
Balance in Forces Acting on Electrons in Molecules
Authors: Isihara Makoto
Published: July 2006

The force theorem is generalized by using the spin-specified momentum operator in the hypervirial theorem. A theorem consequent on this concerns a balance in forces acting on up- and down- spin electrons. The theorem is expected to be useful for examining accuracy of approximate wave functions for open-shell molecules.
Temperature Dependences of 69Ga and 81Br NQR Frequencies in [R4N]2Ga2Br6 (R=CH3 and C2H5)
Authors: Ishihara Hideta , Yamada Koji , Okuda Tsutomu
Published: July 2006

Temperature dependences of 69Ga and 81Br NQR frequencies showed that phase transitions take place at 98 and 137 K in [(CH3)4N]2Ga2Br6 and that the C3 reorientation of the GaBr3 group occurs in [(C2H5)4N]2Ga2Br6 around room temperature.
The Revised Structure of a Dihydrobenzofuran Derivative Isolated from Lasiolaena morii
Authors: Yamaguchi Seiji , Saitoh Akihito , Kawase Yoshiyuki
Published: July 2006

Two isopropenyldihydrobenzofuran derivatives are synthesized. By the comparison of 1H NMR spectra, the proposed structure of a natural dihydrobenzofuran is revised to 4-acetyl-2-isopropenyl-2,3-dihydrobenzofuran-5-ol.
Studies of Polystyrene-Based Ion-Exchange Fiber. IV. A Novel Fiber-Form Material for Adsorption and Immobilization of Biologically-Active Proteins
Authors: Yoshioka Toshio , Shimamura Masaharu
Published: July 2006

A new polystyrene-based ion-exchange fiber (IONEX) has a large surface area per unit weight and has been studied for its ability to adsorb and immobilize biologically-active proteins. A strong cation IONEX was found to be able to effectively adsorb hemoglobin and albumin, invertase, and glucose isomerase were readily adsorbed to a strong anion IONEX. The adsorption of these proteins to IONEX was found to take place through an electrostatic force. The adsorption capacity for proteins became exceedingly large (ca. 300 mg g−1) with an increase in the water-holding capacity of the fiber. The activities of the invertase and glucose isomerase immobilized to the fiber exhibited 40–50 and 75–80%, respectively, of those of native enzymes. A continuous inversion of sucrose was also carried out using immobilized invertase. From these results, this fibrous ion exchanger with a high water-holding capacity is considered to be an excellent material for the adsorption and immobilization of proteins.
Regioselective Preparation of Allylic Sulfones by Palladium-Catalyzed Reactions of Allylic Nitro Compounds with Sodium Benzenesulfinate
Authors: Ono Noboru , Hamamoto Isami , Kawai Takashi , Kaji Aritsune , Tamura Rui , Kakihana Masato
Published: July 2006

Treatment of allylic nitro compounds with sodium benzenesulfinate in the presence of 5 mol% of Pd(PPh3)4 in N,N-dimethylformamide (DMF) at 20–70 °C for 1–10 h resulted in the formation of allylic sulfones with predominance of kinetically controlled products. The product distribution is mainly controlled by the electronic nature of substituents of an allyl unit, and the isomerization to the thermodynamically-stable isomers is negligible. On the other hand, the palladium-catalyzed sulfonylation of allylic acetates with sodium benzenesulfinate is accompanied by the isomerization to give the thermodynamically-controlled products selectively. These results can be explained by assuming that allylic nitro compounds are more reactive to the palladium catalyst than allylic acetates and sulfones.
Synthesis and Reactivity of N-Trifluoromethyl-N-nitrosotrifluoromethanesulfonamide as a New Type of Trifluoromethylating Agent
Authors: Umemoto Teruo , Ando Akira
Published: July 2006

N-Trifluoromethyl-N-nitrosotrifluoromethanesulfonamide (TNS-Tf) was synthesized in a 58% yield by the reaction of trifluoronitrosomethane with hydroxylamine followed by the treatment with trifluoromethanesulfonyl fluoride in the presence of a base. TNS-Tf was demonstrated to be an effective trifluoromethylating agent photochemically or thermally for aromatics, thiols, disulfides, and uridine derivatives. The insertion reaction by two trifluoromethyl groups of TNS-Tf to the sulfur-sulfur bonds was observed in the reaction with disulfides having electron-withdrawing groups, giving 2 mols of trifluoromethylthio compounds. Furthermore, TNS-Tf served as a good reagent for mild and convenient in situ generation of trifluoromethylcopper complex which converted iodoaromatics to trifluoromethyl-substituted aromatics in good yields. Similarly, N-trifluoromethyl-N-nitrosononafluoro-1-butanesulfonamide (TNS-Nf) was synthesized in a 36% yield. The examination of the reactivity indicated that this type of N-nitroso sulfonamides became to be sources of both perfluoroalkyl radicals contained.
Isolation of Dithiolanylium Salts and Their Conversion to Ketene Dithioacetals and Ortho Esters
Authors: Okuyama Tadashi , Fujiwara Wataru , Fueno Takayuki
Published: July 2006

Various 2-substituted 1,3-dithiolan-2-ylium perchlorates (1) were prepared by the reaction of 1,2-ethanedithiol with acyl chlorides in the presence of perchloric acid. Treatments of 1 with triethylamine gave 2-alkylidene-1,3-dithiolane (2) when the 2-substituent was a primary or secondary alkyl group. 2-Aryl derivatives of 1 were converted to ortho esters by the reaction with methanol in the presence of silver nitrate. 1,3-Dithian-2-ylium perchlorates and 2-alkylidene-1,3-dithianes were also prepared similarly from 1,3-propanedithiol.
Adsorption of Cobalt(II) Ions on Crystalline Hydrous Titanium Dioxide Fibers at 298 to 423 K
Authors: Komatsu Y\={u} , Fujiki Yoshinori , Sasaki Takayoshi
Published: July 2006

The distribution of cobalt(II) ions between crystalline hydrous titanium dioxide fibers and aqueous solutions has been investigated. The adsorption behavior of cobalt(II) ions is explained in terms of their ion exchange with hydrogen-ions in the fibers. The distribution coefficients of cobalt(II) ions, Kd, increased with increasing temperature at 298–373 K. Slopes of the plots of logKd vs. pH for 398–423 K were ca. +1.6, which was somewhat lower than those for 298–373 K: +2.0. X-Ray powder diffraction patterns indicate that the fibers hold a layer structure up to 373 K but change to anatase or its precursor above this temperature.
Synthesis of Selenoxides by Oxidation of Selenides with t-Butyl Hypochlorite, and Its Application for Synthesis of Optically Active Selenoxide
Authors: Kobayashi Michio , Ohkubo Hiromi , Shimizu Toshio
Published: July 2006

An effective synthesis of selenoxides by the oxidation of selenides with t-butyl hypochlorite in the presence of methanol and pyridine followed by hydrolysis is descrived. This oxidation method is particularly effective for the oxidation of selenides which possess electron-withdrawing groups. A synthesis of partially optically active selenoxide with bulky substituents can be achieved using a novel oxidation method.
Phase Transition of N-Acyl Amino Acids with Different Acyl Group
Authors: Miyagishi Shigeyoshi , Matsumura Seiichi , Asakawa Tsuyoshi , Nishida Morie
Published: July 2006

The solid-liquid phase transitions of N-acyl amino acids with different acyl groups were investigated using a differential scanning calorimeter and an infrared spectrophotometer. The enthalpy and entropy changes of the transition increased by 3–5 kJ mol−1 and 8–10 J K−1mol−1, respectively, for an additional methylene group in N-acylglycine, and 7 kJ mol−1 and 18 J K−1mol−1, respectively, in the N-acyl-l,-alanine series. The same thermodynamic quantities of N-acylvalines were only slightly dependend on the acyl chain length, while they varied irregularly for the N-acylleucine series. Both the enthalpy and entropy were smaller for the l-form than for its racemic isomer in the N-acylleucines (C12 and above) and N-acylvalines. The differences of the thermodynamic quantities between the l- and Dl-forms seems to result mainly from the difference of the molecular packing in the solid state.
In Situ X-Ray Observation on the Intercalation of Weak Interaction Molecules into Perovskite-Type Layered Crystals (C9H19NH3)2PbI4 and (C10H21NH3)2CdCl4
Authors: Dolzhenko Yuri I , Inabe Tamotsu , Maruyama Yusei
Published: July 2006

The intercalation-deintercalation process of weak interaction organic molecules such as 1-chloronaphthalene and o-dichlorobenzene into highly oriented polycrystalline (C10H21NH3)2CdCl4 films and hexane into (C9H19NH3)2Pbl4 single crystals has been observed in situ by using X-ray technique. The process is highly reversible. Increasing of interlayer spacing is in reasonable agreement with the size of the intercalated molecules and corresponds to the parallel orientation of aromatic ring planes or hexane chains in between two paraffin layers of the host crystals.
Nanosecond Laser Photolysis of N-Methylindole in Acetonitrile
Authors: Kanamaru Nobuaki , Tanaka Jiro
Published: July 2006

Nanosecond laser photolysis (nslp) of N-methylindole (NMI) was investigated using XeCl laser (308 nm) so that excitation is performed at the red edge of the first absorption band. At least three transient absorptions were observed i.e. those to be ascribed to Sn←S1, Tn←T1 transitions and ion-pair like species with peaks at ≈700 nm, ≈460 nm, and ≈380 nm, respectively. The transient absorptions were found to be produced by monophotonic processes. The lifetimes of the triplet state and the ion pair were determined to be ≈3.1 μs and ≈29 μs, respectively, in degassed solutions. Transient photoconductivity (tpc) measured on the same system indicated that there are both rise and decay components. Its fastest decay component of ≈26 μs, is close to that of the transient absorption ascribed to the ion pair. This result provides another example of monophotonic electron ejection through fluorescent states of aromatic amines in polar solvents, such as, acetonitrile.
Pulse Radiolysis Study of Positive-Charge Transfer in Freon-Mixture Matrix at 77 K
Authors: Kira Akira , Imamura Masashi , Tagawa Seiichi , Tabata Yoneho
Published: July 2006

The pulse radiolysis of a Freon mixture (FM), an equivolume mixture of CFCl3 and CF2BrCF2Br, at 77 K gave transient absorption bands with peaks at 360, 490, and 530 nm, whose decay was enhanced by cation scavengers: propylamine, triethylamine, N,N′-diethylaniline, and biphenyl. The degree of the enhancement was independent of the difference in the ionization potential between the matrix and the solute molecules. In the FM matrix, positive-charge transfer from biphenyl cations to some other solute molecules showed energy dependence similar to that observed in the s-butyl chloride matrix. The rate of inter-solute positive-charge transfer was faster in the FM matrix than in the s-butyl chloride matrix. These results were discussed in relation to current electron transfer theories.
Parity Rule. Algorithmic Method for the Assignment of Chiral Centers
Authors: Kotera Mitsuharu
Published: July 2006

A simple new algorithm is presented for the assignment of R⁄S configuration of chiral centers described in any projection form.
Thermal Diffusion of Prototropic Ions in Water
Authors: Takeyama Naokata , Nakashima Kimie
Published: July 2006

Regarding the Soret effect of prototropic ions of H+ and OH− in dilute aqueous solutions, it has been mentioned that heat-of-transport values for ions are in good agreement with those of the activation energies for ionic diffusion in the Arrhenius expression. The physicochemical significance of these facts is discussed in relation to the inclusion of thermal diffusion terms in Kramers’ formula for ordinary diffusion flux.
Estimation of Isomer Ratio of 2,3-Alkanedione Dioxime Using High-Resolution 13C NMR in the Solid State
Authors: Kinoshita Setsuko , Wakita Hisanobu , Masuda Isao
Published: July 2006

High-resolution 13C NMR spectra were measured for the CH3–C(=NOH)–C(=NOH)–R (R=CH3, C2H5, n-C3H7, and n-C4H9) series in the solid state. A commercially available powder, dimethylglyoxime (R=CH3), produced two C2 signals, indicating two isomers: i.e., s-trans-(E,E) and s-cis-(E,E). The ratio of trans: cis was estimated to be 3:1.
The Nernst–Planck Type Equation in Nonequilibrium Thermodynamics
Authors: Kimizuka Hideo
Published: July 2006

A single-term expression of the Nernst–Planck type equation conformable with nonequilibrium thermodynamics has been presented. The equation may be applicable to treat the electric properties of the multi-ionic system, although the individual ion flux is unobservable.
New Application of Crown Ether. VII. Synthesis and Complexation Behavior of Bis(crown ether)s Consisting of a Benzocrown Unit and a Monoazacrown Unit
Authors: He Gong-Xin , Abe Akito , Ikeda Toshihiko , Wada Fumio , Kikukawa Kiyoshi , Matsuda Tsutomu
Published: July 2006

New bis(crown ether)s 3 consisting of a benzocrown unit and a monoazacrown unit connected by an oxyethylene linkage were synthesized. Their complexation behavior proved to be analogous to that of lariat monoazacrown ethers rather than that of bis(benzocrown ether)s.
Flocculation of Iron(III) Oxide Hydrate Sols Induced by α,ω-Type Surfactants
Authors: Esumi Kunio , Yamada Kazuki , Sugawara Toshie , Meguro Kenjiro
Published: July 2006

The interactions of disodium salt of bis(3-sulfopropyl) α,ω-alkanedicarboxylate(C10-α,ω and C12-α,ω) with monodispersed spherical particles of iron(III) oxide hydrate sols were studied by measuring the mean particle size, the zeta-potential and the amounts of adsorption. The sols were flocculated by the addition of small amounts of C10-α,ω and C12-α,ω. The flocks thus formed were redispersed by the further addition of these surfactants. The flocculation of sols upon the addition of α,ω-type surfactants occurred over a wider concentration range than upon the addition of an ordinary surfactant, such as sodium dodecyl sulfate(SDS). Furthermore, the mechanism of redispersion upon the addition of α,ω-type surfactants is different with the two fold adsorption layer in SDS.
Studies of Collectors. VII. Flotation of Heavy Metal Ions by Using Colored Surfactant
Authors: Koide Yoshifumi , Sato Shigekazu , Yamada Kimiho
Published: July 2006

Colored surfactants containing complex radicals(R-Bc, R-Bs, R-Sh, R-S, R-C, R-Ha, and R-Hb) were applied as ion-flotation collectors and foam-fractionation collectors. The extent of floatabilities for the colored complexing surfactants and metal ions was easily recognized by the degree of discoloration. R-Bc, R-Bs, and R-Sh with low HLB values formed floatable complexes in pH 6–9 with Cu2+, Cd2+, Hg2+, Pb2+, and Sr2+. The residual concentrations of R-Sh, R-Bc, and R-Bs were below 0.1 ppm; however, these concentrations gradually increased after obtaining a minimum concentration of metal ions. Since R-C, R-Ha, and R-Hb had high HLB values, they easily floated Cu2+, Pb2+, and Cd2+ by foam fractionation. The concentrations of R-C, R-Ha, and R-Hb in foams or aqueous solutions were correlated to their foaming abilities.
Behavior of the Cadmium Ion-Selective Electrode in Alcohol–Water Mixtures
Authors: Motonaka Junko , Konishi Hiroshi , Ikeda Sanae , Tanaka Nobuyuki
Published: July 2006

In an investigation on the behavior of a cadmium ion-selective electrode in methanol–water and ethanol–water mixtures, potential measurements were carried out with a digital pH/mV meter, a cadmium ion-selective indicator electrode and a silver–silver chloride reference electrode. The calibration curves, slopes of the response, response times, effects of temperature, relation between the potential and the pH-meter reading and selectivity of the electrode were discussed. The response of cadmium ions (electromotive force) was linear between 10−7–10−2 mol dm−3 in water. However, the linear range became narrower with an increase in the alcohol content. The slopes in alcohol–water mixtures (27–33 mV/decade in methanol–water mixtures, 21–29 mV/decade in ethanol–water mixtures) were nearly equal to the Nernstian slope (29.6 mV/decade). The response times of the cadmium ion-selective electrode in 99 v/v% methanol and in 99 v/v% ethanol were somewhat long, but were still within 5 min for all solutions consisting of 10−5–10−1 mol dm−3 of cadmium ions. The selectivity of the cadmium ion-selective electrode in various media was examined by the mixed-solution method using potassium, sodium, calcium and magnesium ions as the interfering ions. It was found that a cadmium ion-selective electrode could be used to determine cadmium ions in an alcohol–water solution, although the response time became longer and the linear range of the response became narrower with an increase in the alcohol content.
On the Mechanism of Transfer of Sodium Ion across the Nitrobenzene/Water Interface Facilitated by Dibenzo-18-crown-6
Authors: Kakutani Tadaaki , Nishiwaki Yoshinori , Osakai Toshiyuki , Senda Mitsugi
Published: July 2006

The question of the site of ionophore–ion complex formation, whether it is in the organic phase (EC), in the aqueous phase (CE), or at the interface (E), in the transfer facilitated by dibenzo-18-crown-6 of sodium ion across the nitrobenzene/water interface was studied by kinetic analysis of the ion transfer using a.c. polarographic method. The results indicate that the interface reaction mechanism (E) is the most probable of the three.
Electrochemical Reduction of Carbon Dioxide Using Iron–Sulfur Clusters as Catalyst Precursors
Authors: Nakazawa Makoto , Mizobe Yasushi , Matsumoto Yoichi , Uchida Yasuzo , Tezuka Meguru , Hidai Masanobu
Published: July 2006

The potential-current relationships of DMF solutions of a series of iron–sulfur compounds have revealed that in the presence of clusters [Fe4S4(SR)4]2− (R=PhCH2 or But) and [M2Fe6S8(SEt)9]3− (M=Mo or W) the electroreduction of CO2 proceeds at the potential shifted by about 0.7 and 0.5 V, respectively, to the positive direction compared to the potential at which CO2 is reduced without any catalyst. When controlled potential electrolysis of a DMF solution containing [Fe4S4(SCH2Ph)4]2− was carried out under CO2 at −2.0 V vs. SCE, phenylacetate and formate were formed as the products resulting from CO2 reduction. The cubane structure of this cluster collapsed rapidly under these conditions. However, when excess amount of PhCH2SH was added to the catholyte, the cluster structure was preserved during a relatively long period of electrolysis, and the yield of phenylacetate increased but that of formate decreased compared with the reaction in the absence of free PhCH2SH.
Studies on Nucleosides and Nucleotides. XII. Carbon-Chain Extension at 5′-Position of Ribonucleosides
Authors: Kimura Junji , Kobayashi Hideyuki , Miyahara Osamu , Mitsunobu Oyo
Published: July 2006

2,6-Di-t-butyl-4-nitrophenol reacted with O2-methyluridine, N3-methyluridine or 4-triazolyl-1-(β-d-ribofuranosyl)-2(1H)-pyrimidinone in the presence of diethyl azodicarboxylate and triphenylphosphine selectively at the 5′-position to give the corresponding 4-(nucleosid-5′-yl-aci-nitro)-2,6-di-t-butylcyclohexa-2,5-dienone (aci-nitro ester of nucleoside) in 39–72% yields along with varied amounts of 5′-deoxy-5′-[N,N′-bis(ethoxycarbonyl)hydrazino]nucleosides. By comparison of the reactions of pyrimidine nucleosides having free 2′- and 3′-hydroxyl groups with those of their 2′,3′-O-isopropylidene derivatives, the ratio of aci-nitxo ester to 5′-deoxy-5′-hydrazinonucleoside was affected by the protecting groups as well as the time required for the addition of diethyl azodicarboxylate to a solution of other reactants. Similarly, N1,N6,2′3′-O-tetrabenzoyladenosine afforded the expected aci-nitro ester in 83% yield. The aci-nitro esters prepared were successfully reacted with stabilized phosphoranes such as (ethoxycarbonylmethylene)triphenylphosphorane or (acetylmethylene)triphenylphosphorane giving 1-[(E)-β-d-ribo-hept-5-enofuranosyl]- or 1-[(E)-β-d-ribo-oct-5-enofuranosyl]-pyrimidines and -purines. When the two stage reactions were carried out by one-pot procedure without isolation of aci-nitro esters, overall yields of alkenofuranosylpyrimidines were markedly improved.
Syntheses of Some 6-Oxa- and 2,8-Dioxabicyclo[3.2.1]octanes in Connection with the Daphniphyllum Alkaloids
Authors: Nishiyama Shigeru , Ikeda Yoichi , Yamamura Shosuke
Published: July 2006

In connection with the daphniphyllum alkaloids, some 6-oxa- and 2,8-dioxabicyclo[3.2.1]octanes, which are included as a partial structure of daphmacrine and codaphniphylline, have been synthesized starting from geraniol.
A Molecular Orbital Approach to the Effect of Acid and Base on Mutarotation of d-Glucose
Authors: Imamura Akira , Okajima Toshiya , Kanda Katsuya
Published: July 2006

Molecular orbital calculations were performed for the study of the mechanism of the mutarotation of d-glucose (in Fig. 1) by the CNDO/2 method. The calculated results for a proposed mechanism are in good agreement with the experimental results in relation to the effect of the acid and the base, suggesting the validity of the proposed mechanism of mutarotation.
X-Ray Crystal Structures of 2,4-Dimethyl-4,4a-dihydro-1H-[1,3,5]triazino[1,2-a]quinoline-1,3,6(2H,5H)-trione and Its Dehydrogenated Derivative. Bond Length and EI Mass Fragmentation
Authors: Sawada Masami , Tanaka Takanori , Takai Yoshio , Furukawa Yoshiro , Hanafusa Terukiyo , Misumi Soichi
Published: July 2006

The crystal structures of the cyclic adduct 1 of 4-quinolinone with methyl isocyanate and its dehydrogenated derivative 2 have been determined by X-ray crystal structure analysis. Both crystal structure data of the C–N bond lengths in the triazinedione-ring skeleton suggest which bonds are broken in the initial EI mass fragmentation followed by the subsequent loss of a neutral MeNCO moiety.
Color Reaction between Indium(III) and o-Hydroxyhydroquinonephthalein, and Its Application
Authors: Mori Itsuo , Fujita Yoshikazu , Fujita Kinuko , Koshiyama Yozo , Kawabe Hiroshi , Tanaka Takeshi , Munakata Reiko
Published: July 2006

Color reaction between indium(III) and o-hydroxyhyroquinonephthalein(Qnph) in the presence of a cationic surfactant was studied, and its application for the spectrophotometry and photometric titration of indium(III) was discussed. The color reaction between Qnph and indium(III) in the presence of hexadecyltrimethylammonium chloride(HTAC) was stable in weakly acidic media. The calibration curve was rectilinear in the range of 0–10 μg/10 cm3 of indium(III) at 560 nm, and the apparent molar absorption coefficient was 1.3×105 dm3 mol−1 cm−1. The Sandell sensitivity was 0.0008 μg/cm2 for indium(III).
Concentration Quenching of Fluorescence from Bridged Synthetic Porphyrins
Authors: Maruyama Kazuhiro , Morikawa Soichi , Osuka Atsuhiro
Published: July 2006

Concentration quenching phenomena of singly and doubly bridged porphyrins and their zinc and magnesium complexes were studied. Hypothetical nonfluorescent dimer trap was suggested to be not a coplanarly stacked face-to-face dimer but a loosely interacting pair.
Substituent Effects. XVI. Acetolysis of 2-Phenylethyl Tosylates
Authors: Fujio Mizue , Funatsu Kimito , Goto Mutsuo , Seki Yoji , Mishima Masaaki , Tsuno Yuho
Published: July 2006

The acetolysis rates of 2-arylethyl tosylates were determined for a series of aryl substituents. The non-linear substituent effect was reasonably accounted for on the basis of two linear LArSR relationships; one for the aryl-assisted (FkΔ) and one for the unassisted (ks) processes, respectively. A precise dissection of the apparent substituent effect into individual effects for both processes was achieved in this manner. The substituent effect on the ks process can be described as a linear function of σ° with a small ρs of −0.19, and that on the FkΔ process in terms of the LArSR Eq., with ρΔ=−3.87 and an rΔ=0.631. The use of σ+ for the FkΔ process failed to give any reasonable dissection. The r value for this FkΔ process is essentially identical to that for the neophyl solvolysis. The unique r value of 0.6 is concluded to be characteristic of β-arylassisted ionization processes in general.
A Fast Kinetic Study of Formation and Decay of 2,2′-Azinobis(3-ethylbenzothiazole-6-sulfonate) Radical Cation in Aqueous Solution
Authors: Maruthamuthu Pichai , Venkatasubramanian Lakshmanan , Dharmalingam Periasamy
Published: July 2006

The kinetics of oxidation of 2,2′-azinobis(3-ethylbenzothiazole-6-sulfonate) (ABTS) to the radical cation, ABTS·+ by S2O82−, HSO5−, MnO4−, Cr2O72−, Ce(IV), and molecular Cl2, Br2, and I2 and further oxidation to the dication, ABTS2+ by the above oxidants except HSO5−, Br2, and I2 have been carried out by the stoppedflow spectrophotometric technique. The first-stage oxidation was followed by monitoring the absorption of ABTS·+ at 417 nm and the second-stage oxidation, by following the disappearance of ABTS·+ or the appearance of ABTS2+ at 513 nm. Both the reactions, formation and decay of ABTS·+ were found to obey a total second-order kinetics, first-order each with respect to [ABTS] or [ABTS·+] and [oxidant]. With I2, ABTS underwent reversible reaction, the stoichiometry of which being,

I2+2ABTS\ightleftarrows2ABTS·++2I− with K=142.8,

whereasBr_2generatedonlytheradicalcationandCl_2gaveadecomposedproductviaradicalcationanddicationintermediates.ABTS^2+formedinpresenceofexcessMnO_4^-,Cr_2O_7^2-,andCe(IV)decayedasinthecaseofCl_2reactionbutinpresenceofS_2O_8^2-thedicationwasstableformorethanthreedays.IntheabsenceofexcessS_2O_8^2-,ABTS^2+wentbacktoABTS^·+,possiblyviaoxidationofwater.TheradicalcationwasconvertedbacktotheparentcompoundABTSbyreducingagentssuchasdithioniteandsulfiteions.
Preparation and Characterization of the Dicobalt(III) Complexes Containing Bridging Di-μ-hydroxo Ligands
Authors: Ama Tomoharu , Kawaguchi Hiroshi , Yasui Takaji
Published: July 2006

Three dicobalt(III) complexes, [(L)Co(μ-OH)2Co(NH3)4]2+ or + (L=edda, (gly)2, or nta), were newly prepared and their structures were assigned on the basis of absorption, 1H NMR, and CD spectral data. Each of them has a structure in which the chromophores of two different types are bridged with two hydroxo ligands and with two hydrogen bonds between carboxyl and amino groups. These three complexes are stable for several days in aqueous solutions.
Comparative Studies of 2-, 3-, and 4-Pyridylpalladium(II) Complexes: Synthesis and Properties
Authors: Isobe Kiyoshi , Nakamura Yukio , Miwa Toshio , Kawaguchi Shinichi
Published: July 2006

Oxidative addition reactions of bromopyridines to tetrakis(triphenylphosphine)palladium(0) gave [{PdBr(2-pyridyl)(PPh3)2] (1b), trans-[PdBr(3-pyridyl)(PPh3)2] (2b), and trans-[PdBr(4-pyridyl)(PPh3)2] (3b), which were converted on treatment with triethylpnosphine to trans-[PdBr(2-, 3-, and 4-pyridyl)(PEt3)2] complexes (1d, 2d, 3d, respectively). Titration with perchloric acid in dioxane–water (1:1 by volume) indicated the basicity sequence of these complexes: 2-pyridyl>>4-pyridyl>3-pyridyl. The bromide ligand in 1b–3b can readily be replaced by Cl−, I−, N3−, NCO−, and NCS−. In each corresponding series the relative thermal stability is in the sequence of 2-pyridyl>4-pyridyl>3-pyridyl. The pyridyl complexes containing triphenylphosphine react with carbon monoxide at ambient temperature and pressure to afford acyl complexes, which produce the corresponding esters by reactions with methanol. They also act as catalysts for cross coupling reactions of bromopyridines.
The Crystal and Molecular Structure of the Hydrated Light Lanthanoid(III) Chloroacetates, [{M(ClCH2CO2)3}3(H2O)5]n, (M=La, Pr, Nd, and Eu)
Authors: Imai Takashi , Shimoi Mamoru , Ouchi Akira
Published: July 2006

The crystal and molecular structures of the hydrated lanthanum(III), neodymium(III), and europium(III) chloroacetates indicated in the title were determined by the single-crystal X-ray diffraction method; these three salts as well as the praseodymium(III) salt are apparently isomorphous. By the same synthetic technique, gadolinium(III) or heavier lanthanoid(III) did not give the isomorphous salts. Their crystals are monoclinic with the space group of P21⁄c, and the cell constants of the neodymium(III) salt, for example, are, a=14.805(4), b=18.765(4), c=14.403(5) Å, β=95.13(3)°. There are crystallographically independent three kinds of nine-coordinated metal atoms: Nd(1), Nd(2), and Nd(3). Among them, Nd(1) and Nd(2) are best approximated as being in a tricapped trigonal prism geometry. The Nd(3) is best regarded as being in a monocapped square-antiprism geometry, although one more additional oxygen atom, O(35), approaches one side face. In the lanthanum(III) complex, O(35) is thought to be ligated to La(3), while in the europium(III) complex O(35) is perfectly removed from Eu(III), being accompanied by a change in the coordination geometry of the ligand. In the crystal, the metal atoms are bridged by carboxylato ligands, forming polymeric chains approximately along [−110] or [110] axis. There are no carboxylato bridges between respective chains, although there are some hydrogen-bondings linking them with each other.
The Crystal and Molecular Structure of Heavy Lanthanoid(III) Chloroacetates in the Hydrated Form, [M3ClCH2CO2)9(H2O)4]n·nH2O (M=Gd, Dy, Er, and Yb)
Authors: Sugita Yoshihiko , Ouchi Akira
Published: July 2006

The crystal and molecular structures of the chloroacetato complexes of gadolinium(III), erbium(III), and ytterbium(III) indicated in the title were determined by the single-crystal X-ray diffraction method. In addition to these three complexes, the isomorphous dysprosium(III) salt was also obtained. Their chemical composition, M3L9·5H2O (where M=Gd, Dy, Er, or Yb; HL=chloroacetic acid), is the same as that of the light lanthanoid(III) (La–Eu) chloroacetates, though the latter crystals are monoclinic. The cell constants of the ytterbium(III) salt, for example, are: triclinic, space group P\bar1, a=13.278(10), b=13.624(6), c=12.067(4) Å α=96.62(3), β=100.68(5), γ=67.40(4)°, Z=2 (including 6 metal atoms). There are three kinds of crystallographically independent metal atoms; Yb(1), Yb(2), and Yb(3): Yb(1) and Yb(2) are octa-coordinated (square-antiprism geometry) and Yb(3) is ennea-coordinated (monocapped square-antiprism geometry). Two oxygen atoms around the last type of the metal atom are the more separated in the higher atomic-number lanthanoid(III) complex, while the other M–O bond lengths decrease, depending on the increase of the metal atomic number. The metal atoms are bridged by carboxylate ions in a chair form along the [111] axis, though in a way different from that of the light lanthanoid(III) complexes.
ESR Studies of the Dynamic Properties of Ion Radicals Captured by Surfactant Micelles
Authors: Suga Kosaku , Maemura Koushi , Fujihira Masamichi , Aoyagui Shigeru
Published: July 2006

ESR spectra of duroquinone anion radical (DQ−), methyl viologen cation radical (MV+), and 5,10-dimethyl-5,10-dihydrophenazine cation radical (DMPZ+) were measured in various aqueous surfactant solutions. The line width of each peak of the ESR spectra for DQ− in cationic and anionic surfactant solutions showed a quadratic dependence on the total nuclear quantum number, M=Σmi (i=1 to 12), of methyl protons of DQ−. The rotational correlation times, τc, of DQ− determined from these dependences, were 10−9–10−8 s in cationic surfactant (dodecyl-, tetradecyl-, and hexadecyltrimethylammonium bromide) solutions, and 10−10–10−9 s in nonionic surfactant (Triton X-100) solution. ESR spectra of MV+ and DMPZ+ in anionic surfactant (sodium dodecyl sulfate; SDS) solution showed anomalous patterns as not exhibiting the hyperfine splittings due to the nitrogen nucleus. These anomalies were explained by the more significant broadening of the outer peaks due to nitrogen splitting compared with the broadening of the central peaks corresponding to the nuclear quantum number of nitrogen, MN=mN1+mN2=0. From these results, the rotational correlation time for DMPZ+ in SDS solution was estimated as about 10−10 s.
Reactivities of Stable Rotamers. XVIII. Reactions of 9-[2-(1-Hydroxyethyl)-1-naphthyl]fluorene Rotamers with Sulfuric Acid and Thionyl Chloride
Authors: Oki Michinori , Tsukahara Jiro , Moriyama Kazuhiro , Nakamura Nobuo
Published: July 2006

Treatment of the title compound with 70% sulfuric acid in 1,2-dimethoxyethane caused cyclization for the ap isomer, whereas it did dehydration to produce a vinyl compound smoothly for the sp. The same treatment with 10% sulfuric acid in 1,2-dimethoxyethane afforded the corresponding vinyl compounds from both rotamers. Treatment of the alcohol with thionyl chloride afforded the corresponding chloride in the case of the sp-alcohol, while it gave the sp-vinyl compound in addition to the ap-chloride in the case of the ap-alcohol. The change in solvents in the reaction of the ap form caused the change in the ratio of the olefin vs. the chloride: The polar solvents enhance the rates of formation of the chloride. Introduction of three deuteriums to the methyl group of the ap-form of the title compound suppressed the formation of the olefin to some extent. The results are explained on the grounds of steric effects in the ion-pair formation from the chlorosulfites and the contribution of the C–H stretching in the transition state of the elimination.
Spectroelectrochemical Determination of Redox Potential of Cytochrome c′ in Rhodospirillum rubrum Chromatophores
Authors: Erabi Tatsuo , Yamashita Yoshiharu , Nishimura Kumiko , Wada Masanori
Published: July 2006

A spectroelectrochemical technique has been used for redox study of cytochrome c′ in chromatophores in the presence of Toluidine Blue O as a mediator. The midpoint potential of cytochrome c′ thus determined was 0 mV (n=1) at pH 7.0, which agreed well with the value determined by redox titration.
Enantioselective Ion-Association Mode between the Tris(ethylenediamine)cobalt(III) Cation and the Bis(μ-(−)589-2,3-dimethyltartrato)diantimonate(III) Anion in Solution
Authors: Yoneda Hayami , Sakaguchi Ushio , Nakazawa Hiroshi
Published: July 2006

By analyzing the intensity changes in the circular dichroism spectra, the association constants of the Λ-and Δ-[Co(en)3]3+ ions with the bis(μ-(−)589-2,3-dimethyltartrato)diantimonate(III) ion were determined to be 58.4±1.9 and 38.6±0.4 respectively in H2O (mol−1 dm3 at 25°C and μ=0.1 (NaClO4)). Based on these data together with the chromatographic data, the enantioselective association mode was discussed.
Concurrent Anodic Cyanation and Methoxylation of Methylated Furans. Oxidation Potential and Reactivity, and Stereochemical Control of Addition
Authors: Yoshida Kunihisa , Fueno Takayuki
Published: July 2006

The potentiostatic electrooxidation of a series of methyl-substituted furans was performed in MeOH that contains NaCN at a Pt anode in a divided cell. In all instances, the 1,4-additions of cyano and/or methoxyl group(s) across the furan ring were achieved. Replacement of an aromatic hydrogen by a cyano group occurred concurrently in some cases. The relative rates of cation radicals toward two different nucleophiles (CN− ion and the solvent MeOH (or the MeO− ion as a result of the equilibrium between CN− ion and the solvent MeOH)) at the electrode surface were determined from the yields of products by using the rate expressions of competitive reactions. There is a linear correlation between the relative reactivity of the furans (on a log scale) and their oxidation potential. The ratio of stereoisomers formed in an electrooxidation of 2,5-dimethylfuran (2,5-DMF) changes with addition of adsorbable compound as well as substrate concentration and this is thought to be due to the influence of concentration (or coadsorbate) on substrate orientation in the adsorption layer.
Evidence for the Similarity Recognition Hypothesis. Structure Dependence of the Selectivity in Oxidation of a Pair of Associating Thiols Each Having an Alkyl Group
Authors: Endo Tadashi , Ueda Takeshi , Isago Takashi , Kato Jun-ichi , Suzuki Takashi , Misaka Makoto , Ito Masato M
Published: July 2006

In base-catalyzed oxidation of a pair of associating thiols [HSCH2–CONHCONH–R1 and HSCH2CH2–NHCONHCO–R2] (R1=n-C4H9, R2=n-CnH2n+1) with oxygen, the selectivity (a measure of molecular recognition) at 35.0°C reached a maximum for R1=R2 (=n-C4H9) both in aqueous acetonitrile (n=2 to 6) and in aqueous ethanol (n=3 to 5).
Optical Resolution and Absolute Configuration of Axially Dissymmetric 2,2′-Dihydroxy-6,6′-dimethylbiphenyl
Authors: Kanoh Shigeyoshi , Tamura Nobuyuki , Motoi Masatoshi , Suda Hiroshi
Published: July 2006

2,2′-Dihydroxy-6,6′-dimethylbiphenyl (1) was successfully resolved into its optically pure forms by the recrystallization of the diastereomeric salts derived from the hydrogenphosphate of 1 and cinchonidine or quinine. The dextrorotatory 1 was determined to have R-configuration.
Synthesis of Liquid Hydrocarbons from Carbon Monoxide and Water with a Hybrid Catalyst
Authors: Tominaga Hiro-o , Miyauchi Michiharu , Fujimoto Kaoru
Published: July 2006

Liquid hydrocarbons were produced from carbon monoxide and water at temperatures from 220 to 280°C and under moderately pressurized conditions (3 atm), by utilizing a hybrid catalyst composed of a Co/SiO2 catalyst and a CO shift conversion catalyst. Most of the steam, either added or formed, was converted to hydrogen in the reaction of H2O with CO on the CO shift catalyst.
Thermodynamic Study on Solvent Extraction of 18-Crown-6–Alkali Metal Ion Complexes and Tetraalkylammonium Ions with Picrate Anions into Benzene
Authors: Takeda Yasuyuki , Matsumoto Yoshiki
Published: July 2006

Enthalpy and entropy changes for ion-pair extractions of tetraalkylammonium ions (Me4N+, Et4N+, n-Pr4N+, n-Bu4N+) with picrate anions, overall extractions of alkali metal (Na, K, Rb, Cs) picrates with 18-crown-6 (18C6), and distribution of 18C6 itself were determined between benzene and water, Me, Et, n-Pr, and n-Bu denoting methyl, ethyl, propyl, and butyl groups, respectively. All the extracted 18C6 complexes were 1:1:1 complexes (alkali metal ion: 18C6: picrate anion). The values of enthalpy and entropy changes are negative for overall extractions of all the alkali metal picrates with 18C6. Plots of thermodynamic quantities for ion-pair extractions of R4NA vs. the number of carbon atoms of R4N+ show a linear relationship, R4N+ and A− being tetraalkylammonium ion and picrate anion, respectively. Enthalpy and entropy changes were calculated for ion-pair extractions of 18C6–alkali metal ion complexes with picrate anions. The thermodynamic parameters for ion-pair extractions of 18C6–alkali metal picrate complexes were compared with those of R4NA, and were discussed in detail from the standpoint of molecular grounds. It was found from these data that the 18C6–K+ complex acts as a structure breaker in water.
Action of Electron-Accepting Quenchers in Photoisomerization of Naphthylethylenes in Polar and Nonpolar Solvents
Authors: Oguchi Takahisa , Arai Tatsuo , Sakuragi Hirochika , Tokumaru Katsumi
Published: July 2006

The quantum yield of trans-cis isomerization of 3,3-dimethyl-1-(2-naphthyl)-1-butene was measured in the presence of various electron-accepting quenchers in benzene or in acetonitrile. In benzene the quantum yield was increased by addition of some of the quenchers; however, in acetonitrile it was decreased under similar conditions. This was attributed to more efficient formation of olefin triplets through an exciplex in benzene than through radical ion pairs in acetonitrile.
NAD(P)+–NAD(P)H Model. 63. Regioselective Reduction of Dienoic Ketones and Aldehydes with an NAD(P)H Model on Silica Gel
Authors: Fujii Masayuki , Nakamura Kaoru , Yasui Shinro , Oka Shinzaburo , Ohno Atsuyoshi
Published: July 2006

The Hantzsch ester reduces carbon–carbon double bonds in α,β-unsaturated ketones and aldehydes under the catalysis of silica gel. The 1,4-selectivity is satisfactorily high even in the reductions of polyenes conjugated to a carbonyl group. Methyl substituent at an olefinic position (α or β to the carbonyl group) retards the reduction. The reduction can be used as a useful tool in obtaining building blocks for the syntheses of terpenoids and their derivatives.
Synthesis of Some Five- and Six-Membered Oxasteroids of Cholestane Series by Ring Contraction and the Mass Spectrometric Fragmentations of Oxasteroids
Authors: Suginome Hiroshi , Yamada Shinji
Published: July 2006

Synthesis of several new five- and six-membered oxasteroids of the cholestane series by the ring contraction of those oxasteroids whose oxygen-containing ring is larger by one member has been achieved. Ring contraction utilizes a series of reactions recently developed by us for the transformation of cyclic ketones into cyclic ethers; it involves a regioselective β-scission of the alkoxyl radical generated by irradiation of the lactol hypoiodite derived from the starting oxasteroid to give the iodoformate followed by its cyclization. The present work demonstrates the versatility of our new method for the synthesis of cyclic ethers and extends the scope of its application. The mass spectral fragmentation of some oxasteroids synthesized in the present and previous work is discussed.
Reinvestigation of Base-Catalyzed Condensation of Ethyl α,α-Dichloroacetoacetate with Aldehydes. A New Synthesis of (±)-Disparlure
Authors: Tsuboi Sadao , Furutani Hiroyuki , Takeda Akira , Kawazoe Kayoko , Sato Sadao
Published: July 2006

The titled reaction gave ethyl 2-chloro-2,3-epoxyalkanoates (2) and ethyl 3-chloro-2-oxoalkanoates in improved yields. The structure of the by-product was revised as 1,5-dichloro-4,8-dialkyltricyclo[5.1.0.03,5]octane-2,6-dione by means of the 13C–1H two-dimensional NMR spectrum and an X-ray crystallographic analysis. Compound 2 was applied to the synthesis of (±)-disparlure, the pheromone of the gypsy moth, in 49% overall yield via 6 steps.
Asymmetric Catalytic Hydrogenations of N-Pyruvoyl-(S)-proline Esters
Authors: Munegumi Toratane , Fujita Manabu , Maruyama Tetsuya , Shiono Shozo , Takasaki Michiaki , Harada Kaoru
Published: July 2006

Asymmetric catalytic hydrogenations of the entitled compounds were carried out over palladium on charcoal in various solvents to afford N-[(S)-lactoyl]-(S)-proline esters with a d.e.(=diastereoisomeric excess) of up to 59%. The stereochemistry of the catalytic hydrogenation was explained by the “chelation mechanism.” And the effects of temperature and bulkiness of the ester groups on the asymmetric induction were also described.
Partial Specific Compressibility and Its Relation to Solvation of Solute Based on Measurements of Suspension System
Authors: Nomura Hiroyasu , Kawaizumi Fumio , Iida Takeshi
Published: July 2006

The relation between limiting partial specific compressibility, \barκ20, and solvation of solute was reviewed and determination of \barκ20 was carried out in different types of solutions; ideal binary mixtures, such as benzene–toluene, and suspension systems of polystyrene latex and colloidal silica. In ideal mixture and polystyrene latex systems, the partial specific compressibility and limiting partial specific volume of each solute were equal to the corresponding value of the solute itself. The \barκ20 of the colloidal silica decreased from a positive to negative value with increasing pH of the media, showing strong hydration in alkaline solution.