bluuebunny/crossref_metadata_2025 huggingface dataset:
The Total Synthesis of Herbimycin A
Authors: Nakata Masaya , Osumi Tomomasa , Ueno Ari , Kimura Takenori , Tamai Tetsuro , Tatsuta Kuniaki
Published: August 2006

The first total synthesis of herbimycin A (1), the benzoquinonoid ansamycin antibiotic, is described. (2E,4S,5R,6S,8S)-5,6-Dimethoxy-9-(4-methoxybenzyl)oxy-2,4,8-trimethyl-2-nonenal (40), corresponding to the C7–C15 portion of the ansa-chain of 1, was prepared from methyl 3,4-anhydro-2-deoxy-2-C-methyl-6-O-(triphenylmethyl)-α-d-altropyranoside (16), which had been previously prepared from methyl α-d-mannopyranoside according to our developed procedure, by using a regioselective epoxide opening [bis(1,2-dimethylpropyl)borane–NaBH4] and a stereoselective hydroboration (BH3·SMe2) as the key steps. This aldehyde 40 was subjected to the Brown’s diastereo- and enantioselective allylation conditions [[(Z)-3-methoxyallyl]diisopinocampheylborane] to afford the desired syn 3-methoxy-1,5-dodecadien-4-ol derivative. Subsequent three-step conversion of this alcohol furnished the synthesis of the C5–C15 ansa-chain aldehyde, (2S,4S,5R,6S,7E,9S,10S)-9-[(t-butyldimethylsilyl)oxy]-4,5,10-trimethoxy-2,6,8-trimethyl-7,11-dodecadienal (7). Union of 7 and the lithiated aromatic chromophore, prepared from N-(triphenylmethyl)-3-bromo-2,5-dimethoxyaniline and butyllithium, provided the coupling product, which was transformed to herbimycin A (1) through elongation of the C1–C4 carbon unit and macrolactamization. This fully enantiospecific synthesis elucidates the absolute stereochemistry of 1.
Functionalization of 1H-Pyrrolo[2,3-b]pyridine
Authors: Minakata Satoshi , Itoh Shinobu , Komatsu Mitsuo , Ohshiro Yoshiki
Published: August 2006

Functionalization of 1H-pyrrolo[2,3-b]pyridine (7-azaindole) was studied to provide new compounds directing toward agrochemicals and/or functional materials. Amino groups such as NH2, NH(CH2)2NH2, and NH(CH2)2NH(CH2)2NH2 were introduced onto 6-position of 7-azaindole to form multidentate agents. 6-Amino and 6-iodo derivatives were easily converted to podant-type compounds, N,N′-bis(1H-pyrrolo[2,3-b]pyridin-6-yl)-1,3-benzenedicarboxamide and bis(1H-pyrrolo[2,3-b]pyridin-6-yl)acetylene, respectively. Polyacetylene having 1H-pyrrolo[2,3-b]pyridyl group as a pendant was obtained by polymerization of 6-ethynyl-7-azaindole synthesized by ethynylation of 6-bromo derivative. As functionalization at 3-position of 7-azaindole, syntheses of 3,3′-selenobis[1H-pyrrolo[2,3-b]pyridine] and the corresponding 3,3′-thio compound, as well as 3-carboxyethenyl- and 3-vinyl-7-azaindoles were performed. Some of these products exhibited high fungicidal activity.
Solidification of Iodide Ion by Reaction with Bi2O3
Authors: Kodama Hiroshi
Published: August 2006

α-Bi2O3 is a candidate material for the immobilization of radioactive iodine. The present paper discusses a method for removing radioactive iodide ion by fixing it into α-Bi5IO7 by a direct reaction with α-Bi2O3; it also reports on experimental conditions under which aqueous iodide reacts with α-Bi2O3 to form a single phase of α-Bi5IO7. α-Bi2O3 was reacted with aqueous iodide in LiI, NaI, KI, and NH4I solutions. Although a previous paper reported that the concentration of aqueous iodide ion was the most important factor to form a single phase of α-Bi5IO7, the present result shows that it is not an important factor. The α-Bi5IO7 single phase can be obtained regardless of the concentration of iodide ion when the ratio of the gram molecular number of the bismuth oxide and the gram ion number of the radioactive iodide ion is adjusted in the range 5 : 2 to 1 : 2 in a LiI solution, 4 : 1 to 1 : 2 in a NaI solution, and 4 : 1 to 1 : 4 in a KI solution. A reaction in a NH4I solution does not produce a single phase of Bi5IO7 at any ratio.
Synthesis and Properties of T-Cage-Type Se-Bridged Polynuclear Co(III) and Rh(III) Complexes with 2-Aminoethaneselenolate (aese). Crystal Structure of [{Co(aese)3}4Zn4O](ClO4)6
Authors: Okamoto Ken-ichi , Watanabe Yuko , Konno Takumi , Hidaka Jinsai
Published: August 2006

The novel T-cage-type Se-bridged polynuclear complexes with 2-aminoethaneselenolate (aese), [{Co(aese)3}4Zn3Cl]5+, [{Co(aese)3}4Zn4O]6+, and [{Rh(aese)3}4Zn4O]6+, have been synthesized. Of these complexes, the spontaneous resolution was recognized for [{Co(aese)3}4Zn4O]Cl6 and [{Rh(aese)3}4Zn4O](NO3)6 with a “complete” [Zn4O]6+ core. The crystal structure of -[{Co(aese)3}4Zn4O](ClO4)6·4H2O was determined by the X-ray diffraction method. The crystal is cubic, space group P213, a = 19.646(2) Å, U = 7582.2(7) Å3, Z = 4, and R = 0.0725. The four octahedral fac(Se)-[Co(aese)3] subunits are bound to the tetrahedral [Zn4O]6+ core in a tetrahedral arrangement, giving an approximate T symmetrical (T-cage-type) structure. The three Se atoms in each fac(Se)-[Co(aese)3] subunit are bound to the three different Zn atoms. For the isomer, the chiral configurations are regulated to Δ for all four fac(Se)-[Co(aese)3] subunits, and S for all 12 bridging Se atoms. The electronic absorption and CD spectral behavior of the complexes are discussed in comparison with those of the related mononuclear and linear-type trinuclear complexes, and the corresponding T-cage-type S-bridged polynuclear complexes.
Preparation and Characterization of Co(III)-Dimethyldithiocarbamato Complexes Containing 1,2-Bis(dimethoxyphosphino)ethane. Molecular Structures of [Co{(CH3)2NC(S)S}{R2P(CH2)2PR2}2] (BF4)2 (R = CH3O and CH3)
Authors: Kita Masakazu , Okuno Masaaki , Kashiwabara Kazuo , Fujita Junnosuke
Published: August 2006

The [Co(dtc)3−n(dmope)n]n+ (n = 1, 2) complexes were prepared, where dtc and dmope denote a dimethyldithiocarbamate ion and 1,2-bis(dimethoxyphosphino)ethane, respectively. The absorption and magnetic circular dichroism (MCD) spectra, and reduction and oxidation potentials were compared with those of the corresponding 1,2-bis(dimethylphosphino)ethane (dmpe) and related complexes. The molecular structures of [Co(dtc)(dmope)2](BF4)2 (1) and [Co(dtc)(dmpe)2] (BF4)2 (2) were determined by the X-ray diffraction method. Crystal data are; for 1, monoclinic, Cc, a = 18.154(5), b = 12.533(2), c = 14.447(3) Å, β = 101.69(2)°, V = 3219(1) Å3, Dx = 1.61, Dm = 1.60(3) g cm−3, and Z = 4, R = 0.044 for 3259 reflections; for 2, monoclinic, P21/a, a = 18.967(3), b = 10.333(1), c = 14.459(2) Å, β = 90.10(2)°, V = 2833.8(7) Å3, Dx = 1.53, Dm = 1.54(4) g cm−3, Z = 4, R = 0.052 for 5662 reflections. The average Co–P bond distance trans to S is 2.186(2) Å for 1 and 2.240(1) Å for 2, and that trans to P is 2.226(2) Å for 1 and 2.278(1) Å for 2. The Co–P distances in 1 are shorter by ca. 0.05 Å than those in 2, while the average Co–S bond distances are similar, 2.288(1) Å for 1 and 2.282(3) Å for 2.
Hydrophobic Vitamin B12. XI. Preparation, Characterization, and Enantioselective Alkylation of Hydrophobic Vitamin B12 Bearing a Binaphthyl Moiety
Authors: Murakami Yukito , Hisaeda Yoshio , Kohno Hiroshi , Ohno Teruhisa , Nishioka Takuya
Published: August 2006

Hydrophobic vitamin B12 derivatives bearing a chiral binaphthyl moiety, hexamethyl 71-decarboxy-71-[(R)-2′-methoxy-1,1′-binaphthyl-2-carboxymethyl]cobyrinate perchlorate [B12–BINAP(R)] and hexamethyl 71-decarboxy-71-[(S)-2′-methoxy-1,1′-binaphtyl-2-carboxymethyl]cobyrinate perchlorate [B12–BINAP(S)], were prepared from cyanocobalamin. These complexes were characterized by means of electronic and circular dichroism spectroscopy as well as by cyclic voltammetry in comparison with those data for a hydrophobic vitamin B12 without a binaphthyl moiety. The enantioselective alkylation of hydrophobic vitamin B12 derivatives at the β-axial site was examined in methanol with various 3-bromo-2-methylpropionic esters by means of 1H NMR spectroscopy. All the hydrophobic vitamin B12 derivatives used here, the one bearing methoxycarbonyl groups as peripheral substituents without a binaphthyl moiety, B12–BINAP(R), and B12-BINAP(S), were found to bind (S)-2-methylpropionates more favorably than the corresponding R-enantiomers; the highest S-selectivity was observed with the latter two derivatives, 65% e.e. The cause of such S-enantioselectivity was discussed with attention to stereochemical configurations of the peripheral substituents placed in the corrin ring.
Thermostable Intramolecular Coupling Products from Some p-Xylylenebis(anthrylcarboxylate)s and the Relationship between Their Thermal Stability and Relative Distortion Energy
Authors: Sasaki Hiroshi , Kobayashi Setsuo , Iwasaki Kishiroo , Ohara Shuichi , Osa Tetsuo
Published: August 2006

The thermal stability of intramolecular coupling products from three kinds of p-xylylenebis(anthrylcarboxylate)s are evaluated. Upon near-UV irradiation, two anthracene moieties in each derivative react at the 9–9′ and 10–10′ positions. The derivatives then from intramolecular coupling products. These coupling products are identified by means of 1H NMR and a linear combination of the atomic orbital coefficients for the highest occupied molecular orbital and the lowest unoccupied molecular orbital from analogues of each derivative. After keeping for 1000 h at a temperature of 60 °C, the coupling products from 2 species of p-xylylenebis(anthrylcarboxylate)s do not revert to the original p-xylylenebis(anthrylcarboxylate)s and are thermostable. However, these thermostable coupling products are reversed to the p-xylylenebis(anthrylcarboxylate)s by UV (260 nm) irradiation. The thermal stability of these coupling products can be explained on the basis of the magnitude of the relative distortion energy.
Spectrophotometric Determination of Thiocyanate by Its Oxidation with Iodate
Authors: Koh Tomozo , Yonemura Yasunobu , Kanai Hiroaki
Published: August 2006

A simple method for the determination of thiocyanate has been proposed, based on the oxidation of thiocyanate to sulfate with iodate in a sulfuric acid medium and on the spectrophotometric measurement of the iodine as triiodide at 350 nm, formed from the excess iodate with iodide added. The complete oxidation of thiocyanate to sulfate using iodate was achieved in a medium containing varying amounts of sulfuric acid at 30 °C. Thiocyanate reacted with iodate with a mole ratio of 1 : 1 under the conditions employed here. The proposed method is approximately 20-fold more sensitive than the conventional method using iron(III) and can be applied to the determination of thiocyanate in the concentration range 5.6 × 10−7−5.2 × 10−5 mol dm−3 (0.31–30.2 μg of SCN− in 10 cm3). The relative standard deviation (n = 1) was 0.44% at the 3 × 10−5 mol dm−3 thiocyanate (17.4 μg of SCN− in 10 cm3) level.
Correlation Analysis of the pKa Values of Mono- and Di-ortho-Substituted Benzoic Acids
Authors: Sotomatsu Tomoko , Shigemura Masao , Murata Yoshiyuki , Fujita Toshio
Published: August 2006

The pKa values of 10 benzoic acids occupied simultaneously at the 2- and 6-positions by various substituent combinations were newly measured in water at 25 °C. The effects of the substituents were analyzed quantitatively with regression analysis and free-energy-related parameters of the Hammett–Taft type. The results were compared with those of the analysis of the pKa of mono-ortho-substituted acids cited in the literature. The resonance effect of substituents in di-ortho-substituted compounds was insignificant, but the electronic effect of the through-space inductive type in terms of the Charton σI and the steric effect in terms of the Taft–Kutter–Hansch Es were not. The overall effects were additive for two substituents. In mono-ortho-substituted acids, a “regular” electronic effect of ortho substituents similar to that of the corresponding para substituents including the resonance effect component was indicated to work in addition to the steric and the through-space inductive effects. The steric and through-space inductive effects of a substituent were almost unchanged regardless of whether the substituent was involved in mono- or di-ortho substitution. A possible rationale integrating the results for mono- and di-ortho-substituted acids was to assume an intermediate formation for the dissociation process in which the carboxyl group is partly ionized and more easily twisted than the nonionized carboxyl group in the initial state.
Electron-Laser Dual Beam Irradiation of 2-Methylbenzophenone
Authors: Ishida Akito , Yamamoto Kazuki , Takamuku Setsuo
Published: August 2006

Pulse radiolysis of 2-methylbenzophenone (MBP) in benzene gave the triplet excited state (3MBP*) which rapidly decayed by intramolecular hydrogen abstraction resulting in the photoenol. Successive laser flash photolysis elucidated the photochemical formation of dihydroanthrone from the photoenol.
Determination of Aluminium in Natural Waters by Ion-Pair Reversed-Phase Partition HPLC
Authors: Kaneko Emiko , Hoshino Hitoshi , Yotsuyanagi Takao , Watabe Ritsuko , Seki Toshihiko
Published: August 2006

An ion-pair reversed-phase partition high-performance liquid chromatography-spectrophotometric detection system with 2,2′-dihydroxyazobenzene has been successfully applied to the determination of μg dm−3 level of aluminium in natural waters. The detection limit is 0.2 μg dm−3 in pure solution, and 1 μg dm−3 for total aluminium in water sample. The relationship between the aluminium concentration and pH value of the ground waters is also discussed.
[14π]Electrocyclization Followed by Preferential [1,9]Hydrogen Migration in the Thermolysis of 1-Formyl-4-[(2,4,6-cycloheptatrienyl)(phenylsulfinyl)methyl]azulene
Authors: Sugihara Yoshikazu , Saito Junji , Murata Ichiro
Published: August 2006

1-Formyl-4-[2,4,6-cycloheptatrienyl)(phenylsulfinyl)methyl] azulene (8b) was thermolyzed at 65 °C for 100 min to give 7,12a-dihydro-2-formyldicyclohept[cd,g]indene (9b), which was isomerized to 1,10-dihydro-2-formyldicyclohept[cd,g]indene (10b), upon heating at the higher temperature.
A Convenient Method for the Preparation of Hydrogensiloxanes
Authors: Yamamoto Yasushi
Published: August 2006

Chlorosilanes containing fluorinated organo-substituents are hydrolyzed in a stirred mixture of 1,1,3,3-tetramethyldisiloxane and hydrochloric acid to give the corresponding hydrogensiloxanes substituted with dimethylsiloxy groups in place of chlorine atoms.
Stereochemical Aspects on the BF3·Et2O Catalyzed Ring Contraction of 5-Substituted 2,3-Epoxycyclohexanones
Authors: Obuchi Kazuyuki , Hayashibe Satoshi , Asaoka Morio , Takei Hisashi
Published: August 2006

In the BF3·Et2O catalyzed rearrangement of 5-substituted 2,3-epoxycyclohexanones, the stereochemistry of the forming quaternary carbon center was directed by the chirality at 5-position.
Preparation of Niobates of Rhodium and Nickel by Chemical Mixing Methods
Authors: Yin Yuan-Gen , Wakasugi Takashi , Shindo Hisakazu , Uchijima Toshio , Kunimori Kimio
Published: August 2006

Niobates of rhodium or nickel by were prepared by double decomposition of aqueous rhodium or nickel salt solution with tetraalkylammonium polyniobate and with alkali orthoniobate or metaniobate, as well as by decomposition of mixed citrates of niobium with Rh or Ni. The niobates thus prepared were shown by X-ray diffraction to be well-crystallized and essentially monophasic. The calcination temperature required to achieve crystallization of all the samples is much lower than ceramic methods.
13C NMR Study of Chloro- and Methylthiophenium Ions
Authors: Yoshino Akihiro , Takahashi Kensuke , Sone Tyo
Published: August 2006

The 13C NMR spectra of fifteen cations formed from chloro- and methylthiophenes were observed in HSO3F solutions at −50 °C. Protonation occurred at one of the α-carbons in all of the cases studied. In these systems, the 13C chemical shifts are classified into four ranges without overlapping. The result is useful for the identification of the carbons in the cationic species. Protonated protons in the cationic species can exchange intramolecularly and intermolecularly, even with those in solvents.
Prismatic and Antiprismatic [42]Ferrocenophanes ([4](1,1′)[4](3,3′)- and [4](1,1′)[4](3,4′)Ferrocenophanes)
Authors: Hisatome Masao , Nakanishi Kunihiko , Yamakawa Koji , Kozawa Kozo , Ucnida Tokiko
Published: August 2006

[4](1,1′)[4](3,4′)Ferrocenophane (2a), also trivially called antiprismatic [42]ferrocenophane, which possesses a C2 symmetric configuration has been synthesized via intramolecular oxidative coupling of the dienolate ion derived from 3,4′-diacetyl[4](1,1′)ferrocenophane. The antiprismatic phane (2a) and the corresponding prismatic [4](1,1′)[4](3,3′)ferrocenophane (1a), which is bridged by a C2ν symmetric mode, has been characterized by X-ray analysis and 1H NMR and electronic spectrometries. The crystal data of the phanes are as follows: 1a, orthorhom-bic, Pbca, a = 18.469(4), b = 19.994(4), c = 7.610(2) Å; Z = 8; 2a, triclinic, , a = 7.547(1), b = 8.540(1), c = 5.886(1) Å, α = 96.60(1), β = 107.10(1), γ = 101.71(1)°, Z = 1. Antiprismatic phane 2a has a completely staggered conformation about the two cyclopentadienyl (Cp) rings, while prismatic 1a has an intermediary conformation of eclipsed and staggered forms. The Cp–Fe–Cp distance of 2a (3.260 Å) is shorter than that of 1a (3.275 Å). The hypsochromic shift of the d–d* absorption band of 2a in the electronic spectrum is more remarkable than that of 1a (ferrocene, 443 nm; 1a, 420 nm; 2a, 403 nm in THF). Those results reveal that an antiprismatic bridging mode with tetramethylene chains brings about a higher strain in the molecule compared with a prismatic one.
The Hydroboration of 3-Chloro-1-iodo-1-propyne with Dialkylboranes, and Its Application to the Syntheses of Some Geminally Dialkylated Propene Derivatives
Authors: Masuda Yuzuru , Hoshi Masayuki , Arase Akira
Published: August 2006

3-Chloro-1-iodo-1-propyne is smoothly hydroborated with dialkylboranes, giving (Z)-(3-chloro-1-iodo-1-propenyl)dialkylboranes exclusively. Subsequent treatment of the hydroboration mixture with sodium methoxide or aqueous sodium hydroxide results in migration of two alkyl groups from the boron atom to the α-alkenyl carbon atom to provide dialkylated allylboranes, which are protonolyzed with methanol or water to produce 1,1-dialkyl-1-propenes. Oxidation of the allylboranes with alkaline hydrogen peroxide prior to protonolysis gives 1,1-dialkyl-2-propen-1-ols. Treatment of (Z)-(3-chloro-1-iodo-1-propenyl)dicyclohexylborane with Grignard reagents, followed by protonolysis with acetic acid, provides 3-alkyl-3-cyclohexyl-1-propenes in which the alkyl group is derived from Grignard reagent.
13β-Hydroxylation of Milbemycins by Selenium Dioxide
Authors: Tsukamoto Yoshihisa , Sato Kazuo , Kinoto Takao , Yanai Toshiaki
Published: August 2006

Introduction of a hydroxyl group to milbemycin nucleus was examined. Starting from 5-oxo-5-deoxymilbemycins, 13β-hydroxy-5-oxo-5-deoxymilbemycins were obtained stereo- and regioselectively by selenium dioxide oxidation in formic acid and subsequent acidic hydrolysis. The stereochemistry of the hydroxyl group was elucidated by 1H NMR study.
Synthesis of Benzochlorin Monomer, Dimer, and Porphyrin-Benzochlorin Heterodimer from 5-Aryl- and 5,15-Diaryl-octaethylporphyrins
Authors: Osuka Atsuhiro , Ikawa Yoshiya , Maruyama Kazuhiro
Published: August 2006

Vinylogous Vilsmeier formylation of nickel(II) 5,15-di-p-tolyl-octaethylporphyrin gave the corresponding meso-(2-formylvinyl)porphyrin, which, on treatment with trifluoroacetic acid, provided the corresponding benzochlorin derivative. In the case of the copper(II) complex, Lewis acid such as BF3·Et2O and SnCl4 catalyzed the cyclization to the benzochlorin without demetallation. Similar vinylogous Vilsmeier formylation of the nickel(II) and copper(II) complexes of 5-p-tolyloctaethylporphyrin resulted in the selective formation of 5-p-tolyl-10-(2-formylvinyl)porphyrin. Subsequent cyclization of these metal complexes took place with marked different regioselectivity; the nickel(II) complex favors the cyclization at near the 5-p-tolyl substituent, while the copper(II) complex favors the cyclization at the opposite site. Application of these synthetic methods to the 4,4′-biphenylylene-bridged diporphyrin led to the synthesis of porphyrin–benzochlorin heterodimer and benzochlorin homodimer. The steady-state fluorescence spectrum of free base form of the heterodimer suggested the intramolecular singlet excitation energy transfer from the porphyrin to the benzochlorin.
Cd2+-Catalyzed Methanolysis of Phenyl Phosphatosulfate. Selectivity of Metal Ion in the Site of Cleavage of P–O and S–O Bond
Authors: Eiki Toshio , Negishi Shin-ichi , Tagaki Waichiro , Izumi Mitsunori , Ichikawa Kazuhiko
Published: August 2006

It was reported previously that metal ions such as Mg2+, Cr3+, Cu2+, Mn2+, and Ca2+ catalyzed selective P–O bond cleavage of P–O–S linkage in the methanolysis of phenyl phosphatosulfate (PPS), and in contrast, metal ions such as Zn2+, Fe3+, Al3+, and Be2+ promoted selective S–O bond cleavage.1) We have now found that Cd2+ catalyzes mixed cleavage of P–O and S–O bond in a ratio of 58 and 42%, respectively, in the methanolysis of PPS. The value of second-order-rate constant (k2) for Cd2+ catalyzed P–O bond cleavage satisfied the correlation between values of k2(P–O) and ionic radii of metal ions, but that for Cd2+ catalyzed S–O bond cleavage was considerably smaller than that expected from the rate correlation. The presence of chloride ion reduced the rate of Cd2+ catalyzed P–O bond cleavage to about one tenth of that in the absence of chloride ion, but inhibited completely the S–O bond cleavage catalyzed by Cd2+ or Zn2+. The kinetic studies suggested that the inhibition by chloride ion occurred with the formation of ternary (PPS·Cd2+·Cl−) and tetramerous (PPS·Zn2+·2Cl−) complexes of substrate, metal ion and chloride ion. On the basis of these results the selectivity of the metal ion in the site of bond cleavage was discussed.
Thermoanalytical Study of Dioxygencobalt(III) Complexes with N,N′-Ethylenebis(salicylideneaminate) and Its Derivatives
Authors: Miyokawa Kikuo , Kinoshita Setsuko , Etoh Takumi , Wakita Hisanobu
Published: August 2006

The oxygen-dissociation reactions of [Co(3-X-salen)]2O2, where 3-X-salen is N,N′-ethylenebis(3-substituted salicylideneaminate) dianion, X = H (1), OCH3 (2), OC2H5 (3), NO2 (4), have been studied by means of a thermoanalytical technique. The heat of the reaction, determined by DTA, ranges from 88 (4) to 120 (2) kJ mol−1; the electron-releasing substituents tend to stabilize the Co–O2 bonding. The O2-dissociation process is best described by the first-order equation and the activation enthalpies range from 117 (4) to 145 (2) kJ mol−1 and the electron-releasing substituents increase the activation enthalpy. A kinetic compensation effect was observed, except for 3, which is the most stable of these complexes due to its small activation entropic value.
Synthesis of 3-Deoxy-5-O-mycaminosyltylonolide and 3-Deoxy-5-O-(4-deoxymycaminosyl)tylonolide
Authors: Kageyama Shunji , Tsuchiya Tsutomu , Umezawa Sumio , Orita Masaya
Published: August 2006

The title compounds, which proved highly antibacterial, have been prepared by selective hydrogenation of the corresponding 2,3-unsaturated compounds with LiAlH4, diisobutylaluminium hydride, or NaBH4–NiCl2 as the key steps. Further, the latter title compound was prepared effectively through the reaction of 3-O-benzylsulfonyl-5-O-(4-deoxy-4-iodomycaminosyl)-23-O-(dimethylthexylsilyl)tylonolide 9,20-bis(ethylene acetal) with Raney Ni–K2CO3 involing three steps in it.
Preparation and Properties of Immobilized Glucoamylase on a Magnetically Anisotropic Carrier Comprising a Ferromagnetic Powder Coated by Albumin
Authors: Sakai Yasuzo , Osada Katsumi , Takahashi Fujio , Takada Susumu
Published: August 2006

Glucoamylase was immobilized by glutaraldehyde combined with albumin coated on the surface of a powder of SrFe2O4 as the carrier. This carrier obtained a magnetically anisotropic property under exposure to a static magnetic field. The carrier was able to oscillate and rotate in an alternating magnetic field. The rate of hydrolysis of starch to glucose increased in the alternating magnetic field. This is because the transport of molecules may be facilitated through the interface of the carrier surface and solution by oscillation.
Role of the Structure and Electronic Properties of Fe2O3-MoO3 Catalyst on the Dehydration of Isopropyl Alcohol
Authors: Said Abdel-Aziz Ahmed
Published: August 2006

Molybdenum oxide catalysts doped or mixed with (1–50) mol% Fe3+ ions were prepared. The structure of the original samples and calcined at 400 °C were characterized using DTA, X-ray diffraction, and IR spectra. The measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mol%. The activation energies of charge carriers were determined in presence and absence of alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mol% Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted between the catalyst composition and their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.
Real Time Optical Observation of Nascent Hexafluorobutadiene in the IR Multiphoton Dissociation of Decafluorocyclohexene
Authors: Chowdhury Pradyot Kumar
Published: August 2006

Real time observation of retro-Diels–Alder dissociation of decafluorocyclohexene into tetrafluoroethylene and hexafluorobutadiene induced by transversely excited atmospheric pulsed CO2 laser is reported. The formation rate and the red-shifted absorption spectra of nascent hexafluorobutadiene suggest substantial internal energy incorporation, which appears to be sufficient for its undergoing electrocyclic transformation to hexafluorocyclobutene at a rate corresponding to the decay kinetics. When the above IR multiphoton dissociation of decafluorocyclohexene occurs in presence of oxygen, UV light emission due to COF2* is observed.
Adsorption-Induced Electrical Conductivity of Some Ferrocene Derivatives: Rates of Adsorption and Desorption of Vapors
Authors: Bhattacharjee Ashis , Mallik Biswanath
Published: August 2006

The change in dark conductivity of some ferrocene derivatives on adsorption of some organic solvent has been studied in sandwich cell configurations at different cell temperatures. Appreciable enhancements in the dark conductivity are observed. Such enhancement depends on the amount of adsorbed vapor, cell temperature as well as the chemical nature of the adsorbate. The sensitivity towards a vapor is also found to vary depending on the nature of the substituent groups in the ferrocene ring. Both the adsorption and desorption rates follow the modified Roginsky–Zeldovich equation. The temperature dependence and the nature of the solid-vapor interaction have been deduced from the rate data analysis.
Crystal Structure and Molecular Conformation of 1-O-Acetyl-2,3,5-O-benzoyl-β-d-ribofuranose
Authors: Kingsford-Adaboh Robert , Kashino Setsuo
Published: August 2006

The crystal structure of a derivative of β-d-ribofuranose has been determined by X-ray diffraction method in order to characterize the molecular conformation. The phase angle P and the degree of puckering τm of the sugar ring are −7.6 and 34.3° respectively. The ring shows C(3′)-endo-C(2′)-exo puckering () as found in sucrose and 1,2,3,5-tetra-O-acetyl-β-d-ribofuranose. The furanoid carbons C(1′), C(2′), and C(3′) adopt the cis conformation with the carbonyl oxygens of their corresponding side chains. This conformation is favored by intramolecular C–H···O=C interactions. All carbonyl oxygens also participate in intermolecular C–H···O=C interactions in the crystal.
Diffusion Coefficient of Benzene around the Gas-Liquid Critical Temperature
Authors: Saitoh Takayuki , Nakamura Yoshio , Shimokawa Shigezo
Published: August 2006

The diffusion coefficients of benzene in a pressurized vessel has been measured up to above the gas–liquid critical temperatures. The observed diffusion coefficients are compared with the calculated values from a simple hard-sphere approach.
Crystal and Molecular Structure of 1,5-Seco-grayanotoxin-1,3,6,14,16-pentaacetate
Authors: Sato Mamoru , Katsube Yukiteru , Terai Tadamasa , Katakawa Jun’ichi , Tetsumi Tadahiro
Published: August 2006

The three dimensional structure of 1,5-seco-grayanotoxin-1,3,6,14,16-pentaacetate has been determined by X-ray diffraction at room temperature. The monoclinic structure was refined by the full matrix least-squares method to a final R = 0.037 for 2269 independent reflections. The molecule has a tricyclic structure that consists of ten-, six-, and five-membered rings. The absolute configuration at C1 atom was determined as S on the basis of internal comparison with the absolute structure of 1,5-seco-grayanotoxin-1(R),3,6,14,16-pentaacetate.
Copper(II) Complexing Capacity of River Waters in the Urban Area
Authors: Kawamoto Hiroshi , Ishida Wataru , Tsunoda Kin-ichi , Akaiwa Hideo
Published: August 2006

Hourly variation of copper(II) complexing capacity (CuCC) of water samples from the Kiryu River in Gunma prefecture was investigated. From the stand point of complexing capacity, the present water samples could be classified into two types, that is, the daytime type and the nighttime one. Water sampled belonging to the former type contained some ligands derived from human activity, and naturally occurring ligands were mainly found in water samples belonging to the latter. The estimation of stability constant for copper(II) complex in water samples was also carried out on the basis of a single ligand model.
Complexation Property of a Novel Macrobicyclic Polyether with Two Amide Moieties toward Alkali Metal and Alkaline Earth Metal Cations
Authors: Nakatsuji Yohji , Inoue Toshinori , Masuyama Araki , Okahara Mitsuo
Published: August 2006

A new type of macrobicyclic compound, which was prepared by the reaction of 2,9-bis[(ethylamino)methyl]-15-crown-5 with sebacoyl dichloride, has shown a selective complexation property toward K+ and Ba2+ cations based on data obtained with potentiometric titration and solvent extraction. This finding was reasonably explained by considering the cooperative binding of the amide moieties and the crown ring. The coordination direction of the carbonyl oxygens was found to markedly affect its complexation property by comparing its complexing ability with those of lariat ethers having one or two amide side arms.
Synthesis and Reactions of Some Crowded Triorganylbismuthines
Authors: Matano Yoshihiro , Kinoshita Masamichi , Suzuki Hitomi
Published: August 2006

Bismuth trichloride reacts smoothly with mesityl- and 2,4,6-triisopropylphenylmagnesium bromides in boiling tetrahydrofuran to form the corresponding triarylbismuthines in good yields, while a similar reaction with 2,4,6-triisopropylphenylmagnesium bromide halts at diarylation stage, giving chlorobis(2,4,6-triisopropylphenyl)bismuthine as the sole product. Several crowded alkyl-, alkenyl-, and alkyn-yldiarylbismuthines have been prepared from the above diarychlorobismuthine through the reaction with an appropriate organolithium reagent.
Nonfluorous, Highly CO2-soluble Chelating Ligands for scCO2 Metal Ion Extraction
Authors: Yang Hai-Jian
Published: August 2006

A series of new nonfluorous chelating ligands derived from glucose have been designed and synthesized. All compounds are highly soluble in liquid or supercritical carbon dioxide. Solubility trend of these chelating compounds would be rationalized by the inductive effect of substituent on the benzene ring and the easy accessibility of benzylic ether oxygen and neighboring hydrogens. Preliminary metal ion extraction efficiency test showed that all our compounds are selective for Sr2+ and Pb2+ extraction.
Lewis Base-catalyzed Alkynylation of Carbonyl Compounds with Trimethylsilylacetylenes
Authors: Kitazawa Takayuki , Minowa Tomofumi , Mukaiyama Teruaki
Published: August 2006

Alkynylation of carbonyl compounds with trimethylsilylacetylenes in the presence of a catalytic amount of Lewis bases such as acetate or phenoxide anion is described. The alkynylation proceeded under mild conditions and afforded the corresponding propargyl alcohols in good to excellent yields.
Highly Efficient Methanolysis of Bicyclic β-Lactams to β-Amino Ester Using Silica Chloride
Authors: Sathe Manisha , Ghorpade Ramarao , Kaushik Mahabir Parshad
Published: August 2006

Silica chloride is used as an effective heterogeneous catalyst for the methanolysis of highly constrained cyclic β-lactam to afford β-amino ester under mild acidic conditions with quantitative yields.
Short Synthetic Route toward the Tricyclic Core of Schulzeines
Authors: Kuntiyong Punlop , Akkarasamiyo Sunisa , Eksinitkun Gedsirin
Published: August 2006

The tricyclic core of marine natural products schulzeines was synthesized using N-acyliminium ion cyclization. The intermediate N-acyliminium ion was generated from treatment of α-hydroxy-δ-lactam with a Lewis acid. The tricyclic products were obtained as a mixture of 2 diastereomers at the C-11b stereocenter. The diastereomeric ratios were low and dependent on the Lewis acid used in the reaction.
Chemically Nonequivalent Sites in Mesoporous BCN Revealed by Solid-state NMR at 21.8 T
Authors: Murakami Miwa , Shimizu Tadashi , Tansho Masataka , Vinu Ajayan , Ariga Katsuhiko , Takegoshi Kiyonori
Published: August 2006

Solid-state 11B magic-angle spinning (MAS) NMR studies on novel mesoporous BCN material are described. While the 11B MAS spectrum at 11.7 T shows severe signal overlap as a result of the second-order quadrupolar broadening, the resolution improves significantly at 21.8 T and three distinct peaks are observed, indicating the presence of three sites in the material. Possible microstructures of the three sites are discussed in terms of their isotropic chemical shifts, quadrupolar coupling constants, and asymmetric parameters determined from spectral simulation.
Gel Nitridation Preparation and Luminescence Property of Eu-doped RE2O2CN2 (RE = La and Gd) Phosphors
Authors: Takeda Takashi , Hatta Naoya , Kikkawa Shinichi
Published: August 2006

RE 2O2CN2 (RE = La, Eu, and Gd) and Eu-doped RE2O2CN2 (RE = La and Gd) phosphors were prepared by nitridation of oxide precursors through rare earth citrate gel. This preparation method increased the doping limit to 20 atom % in La2O2CN2. The value was considerably wider than 7 atom % of solid-state synthesis through rare earth oxide. Eu-doped Gd2O2CN2 was firstly synthesized by this method. The shape of luminescence spectra and luminescence intensity were different between these oxycyanamides reflecting the difference in their crystal structure and crystallinity.
Fabrication of TiO2 and Cytochrome c Alternate Ultrathin Films via a Gas-phase Surface Sol–Gel Process
Authors: Yang Do-Hyeon , Takahara Naoki , Mizutani Naoki , Lee Seung-Woo , Kunitake Toyoki
Published: August 2006

A gas-phase surface sol–gel process was developed for facile preparation of ultrathin TiO2 gel/Cyt. c multilayered films. Positively charged Cyt. c protein was alternately assembled with TiO2 gel layer that was prepared by deposition of Ti(O–nBu)4 vapor and subsequent hydrolysis. The adsorbed Cyt. c molecule was covered with a 0.7-nm thick layer of TiO2 gel and the protein characteristics were preserved without denaturation in the multilayered film.
A Novel Organic–Inorganic Hybrid Based on Tungstoantimonate: Synthesis, Crystal Structure, and Properties of Na[{Cu(2,2′-bpy)(H2O)}2{Cu(2,2′-bpy)}2(B-α-SbW9O33)]·2H2O
Authors: Wang Jingping , Ma Pengtao , Li Jie , Niu Jingyang
Published: August 2006

A novel organic–inorganic hybrid tungstoantimonate Na[{Cu(2,2′-bpy)(H2O)}2{Cu(2,2′-bpy)}2(B-α-SbW9O33)]·2H2O (2,2′-bpy = 2,2′-bipyridine) was synthesized hydrothermally and characterized by elemental analyses, IR, EPR, TG, and X-ray single-crystal diffraction, whose polyoxoanion consists of two [Cu(2,2′-bpy)]2+ and two [Cu(2,2′-bpy)(H2O)]2+ complex groups grafted on a trivacant polyoxoanion B-α-[SbW9O33]9− skeleton.
α-Tocopherol supplementation reduces the elevated 8-hydroxy-2-deoxyguanosine blood levels induced by training in basketball players
Authors: Tsakiris Stylianos , Parthimos Theodore , Tsakiris Theodore , Parthimos Nickolaos , Schulpis Kleopatra H.
Published: August 2006

Clin Chem Lab Med 2006;44:1004–8.
Laboratory medicine in the 2000s: programmed death or rebirth?
Authors: Guidi Gian Cesare , Lippi Giuseppe
Published: August 2006

Changes have occurred in the organization, complexity and role of medical laboratories in healthcare, requiring a great increase in global productivity and diagnostic efficiency by enrolled professionals to withstand new challenges. Such a radical evolution, which should be very attractive for new generations of professionals, is counterbalanced by an increasing shortage of laboratory vocations worldwide, particularly in community hospital and large reference laboratories, which may lead to a serious crisis in the field of laboratory medicine in the very near future. Some reasons can be highlighted, including the decreased interaction between clinicians and laboratory professionals, centralized testing, and the development of innovative, minimally invasive techniques that can easily be handled without direct control or supervision by laboratory staff. The prospect of a professional decline in laboratory medicine can be offset by increased awareness of the radical changes occurring within clinical laboratories and re-professionalization of laboratory scientists. This will require new resources to attract young professionals, and should include reaffirmation of the role of laboratory consultants and active participation in the development, implementation and monitoring of innovative diagnostic systems. The “patient” appears to be in a serious condition; it is in our hands to let him be reborn.

Clin Chem Lab Med 2006;44:913–7.
An improved laboratory protocol to assess subarachnoid haemorrhage in patients with negative cranial CT scan
Authors: Apperloo Joke J. , van der Graaf Fedde , Dellemijn Paul L.I. , Vader Huib L.
Published: August 2006

Clin Chem Lab Med 2006;44:938–48.
Measurement of carnitine in hemodialysis patients – adaptation of an enzymatic photometric method for an automatic analyzer
Authors: Cibulka Roman , Siroka Romana , Trefil Ladislav , Racek Jaroslav , Vesela Eugenie
Published: August 2006

Clin Chem Lab Med 2006;44:983–6.
A robust liquid chromatography tandem mass spectrometry method for total plasma homocysteine determination in clinical practice
Authors: Ducros Véronique , Belva-Besnet Hélène , Casetta Bruno , Favier Alain
Published: August 2006

Clin Chem Lab Med 2006;44:987–90.
Poor prognosis indicated by nucleated red blood cells in peripheral blood is not associated with organ failure of the liver or kidney
Authors: Stachon Axel , Holland-Letz Tim , Kempf Reiner , Becker Andreas , Friese Jochen , Krieg Michael
Published: August 2006

Clin Chem Lab Med 2006;44:955–61.
A cost-effectiveness evaluation of reticulocyte measurement in new outpatients with or without hematologic disorders
Authors: Miyachi Hayato , Asai Satomi , Takemura Yuzuru
Published: August 2006

Clin Chem Lab Med 2006;44:1035–8.
Somatic cell nuclear transfer alters peri-implantation trophoblast differentiation in bovine embryos
Authors: Arnold Daniel R , Bordignon Vilceu , Lefebvre Réjean , Murphy Bruce D , Smith Lawrence C
Published: August 2006

Abnormal placental development limits success in ruminant pregnancies derived from somatic cell nuclear transfer (SCNT), due to reduction in placentome number and consequently, maternal/fetal exchange. In the primary stages of an epithelial–chorial association, the maternal/fetal interface is characterized by progressive endometrial invasion by specialized trophoblast binucleate/giant cells (TGC). We hypothesized that dysfunctional placentation in SCNT pregnancies results from aberration in expression of genes known to be necessary for trophoblast proliferation (Mash2), differentiation (Hand1), and function (IFN-τ and PAG-9). We, therefore, compared the expression of these factors in trophoblast from bovine embryos derived from artificial insemination (AI), in vitro fertilization (IVF), and SCNT prior to (day 17) and following (day 40 of gestation) implantation, as well as TGC densities and function. In preimplantation embryos, Mash2 mRNA was more abundant in SCNT embryos compared to AI, while Hand1 was highest in AI and IVF relative to SCNT embryos. IFN-τ mRNA abundance did not differ among groups. PAG-9 mRNA was undetectable in SCNT embryos, present in IVF embryos and highest in AI embryos. In postimplantation pregnancies, SCNT fetal cotyledons displayed higher Mash2 and Hand1 than AI and IVF tissues. Allelic expression of Mash2 was not different among the groups, which suggests that elevated mRNA expression was not due to altered imprinting status of Mash2. The day 40 SCNT cotyledons had the fewest number of TGC compared to IVF and AI controls. Thus, expression of genes critical to normal placental development is altered in SCNT bovine embryos, and this is expected to cause abnormal trophoblast differentiation and contribute to pregnancy loss.
Rate- and depth-dependent nanomechanical behavior of individual living Chinese hamster ovary cells probed by atomic force microscopy
Authors: Zhao Minhua , Srinivasan Charudharshini , Burgess Diane J. , Huey Bryan D.
Published: August 2006

A single elastic modulus is not sufficient for describing the mechanical behavior of a living cell due to its viscoelastic nature and heterogeneity beneath the membrane. In this paper, the nanoscale elastic and viscoelastic behavior of individual living Chinese hamster ovary (CHO-K1) cells in a physiological environment were probed by atomic force microscopy (AFM) indentations at various loading rates. Based on Hertzian fits of the force–distance curves, the apparent elastic modulus of the cells was determined and found to be a function of the loading rate as well as the indentation depth. Notably, contributions from the substrate were negligible up to 50% of the cell thickness. For increased indentation rates and depths, healthy spindle-shaped CHO-K1 cells were found to exhibit an increased change of stiffness, whereas for unhealthy oval- shaped CHO-K1 cells there was little stiffening at equivalent loading rates and depths. Furthermore, a larger hysteresis between the loading and unloading curves was observed with increasing loading rates, which was related to the viscoelastic behavior of CHO-K1 cells. This work demonstrates differences in the rate- and depth-dependent elastic behavior at the nanoscale level between healthy and unhealthy mammalian cells.
Atomistic and continuum modeling of mechanical properties of collagen: Elasticity, fracture, and self-assembly
Authors: Buehler Markus J.
Published: August 2006

We report studies of the mechanical properties of tropocollagen molecules under different types of mechanical loading including tension, compression, shear, and bending. Our modeling yields predictions of the fracture strength of single tropocollagen molecules and polypeptides, and also allows for quantification of the interactions between tropocollagen molecules. Atomistic modeling predicts a persistence length of tropocollagen molecules ξ ≈ 23.4 nm, close to experimental measurements. Our studies suggest that to describe large-strain or hyperelastic properties, it is critical to include a correct description of the bond behavior and breaking processes at large bond stretch, information that stems from the quantum chemical details of bonding. We use full atomistic calculations to derive parameters for a mesoscopic bead-spring model of tropocollagen molecules. We demonstrate that the mesoscopic model enables one to study the finite temperature, long-time scale behavior of tropocollagen fibers, illustrating the dynamics of solvated tropocollagen molecules for different molecular lengths.
Mapping the structure, composition and mechanical properties of bamboo
Authors: Low I.M. , Che Z.Y. , Latella B.A.
Published: August 2006

The structure, composition, and mechanical response of Australian bamboo were investigated. The graded structure, composition, and mechanical properties were confirmed by depth profiles obtained using synchrotron radiation diffraction and Vickers indentation. The mechanical performance of bamboo was strongly dependent on age. Results indicated that young bamboo has a higher strength, elastic stiffness, and fracture toughness than its older counterpart does. In addition, the hardness of bamboo is both load dependent and time dependent as a result of an expanding interfacial damage zone and indentation creep, respectively. In addition to fiber debonding, crack deflection and crack-bridging are the major energy dissipative processes for imparting a high toughness in bamboo.
Hardness and elastic properties of dehydrated cuticle from the lobster Homarus americanus obtained by nanoindentation
Authors: Sachs C. , Fabritius H. , Raabe D.
Published: August 2006

The mechanical properties of biological materials are well adjusted to their function. An excellent example for such materials is the cuticle or exoskeleton of arthropods. In this study, dehydrated cuticle of the American lobster Homarus americanus was examined as a model for a mineralized biological composite material. Nanoindentation testing is a powerful method for revealing gradients and anisotropy in the hardness and the elastic properties of such materials. The air-dried test specimens stem from different parts of the crusher claw with different biological functions. Both the exocuticle and the endocuticle were probed in normal and in the transverse direction to the cuticle surface. For estimating variations in the grade of mineralization, the samples which were tested as cross-sections of the cuticle were analyzed by the use of energy dispersive x-ray mapping. The microstructure of fracture surfaces of the test specimens was investigated using scanning electron microscopy. Due to the use of dehydrated samples, our results do not reflect the exact properties of lobster cuticle in the natural hydrated state, but they can be regarded as a fairly good approximation to the in vivo state.
Mechanical stability optimization of Flemion-based composite artificial muscles by use of proper solvent
Authors: Wang Jin , Xu Chunye , Taya Minoru , Kuga Yasuo
Published: August 2006

Ionic polymer metal composite (IPMC) is a promising candidate for artificial muscles and other bio-related applications. Compared with the widely reported Nafion, Flemion-based IPMC has some more attractive advantages. To improve its mechanical stability in dry environments, the organic solvent glycerol was applied. The mechanical characteristics such as tip displacement, tip force and durability were measured and analyzed. The results showed that Flemion-based IPMC with glycerol as solvent has optimum mechanical stability in dry conditions and will be a good candidate for artificial muscles working in air.
Crystal growth via spiral motion in abalone shell nacre
Authors: Yao Nan , Epstein Alexander , Akey Austin
Published: August 2006

We present a structural feature of nacre in the red abalone shell: micrometer-scale screw dislocations in the aragonite layers and resultant growth via spiral motion. Compared to typical ionic or covalent crystals, nacre contains 106screw dislocations per square centimeter, a difference of three orders of magnitude. Using electron microscopy, ion microscopy, and anin situnano-manipulator, we studied the structure of screw dislocation cores in detail. We considered that these screw dislocations contribute significantly to the strengthening mechanisms that lead to nacre's extraordinary work of fracture, which is three orders of magnitude greater than that of aragonite and other monolithic crystals. This work suggests that the lamellar layers of aragonite propagate via a large number of continuous spiral growth domains as the “stacks of coins” become confluent. This model may provide a basis for creating new comparable micro/nanocomposites through synthetic or biomineralization means.