bluuebunny/crossref_metadata_2025 huggingface dataset:
C-S Bond Cleavage of Allyl Thioethers by Zerovalent Ru Complexes
Authors: Planas Jose Giner , Hirano Masafumi , Komiya Sanshiro
Published: March 2003

The reaction of allyl phenyl or methyl sulfide with Ru(cod)(cot) (1) [cod: 1,5-cyclooctadiene, cot: 1,3,5-cyclooctatriene] in the presence of depe [1,2-bis(diethylphosphino)ethane] causes cleavage of the allyl sulfur bond to afford the cationic π-allyl ruthenium complex, [Ru(η3-C3H5)(depe)2)] [RS] (R = Ph, 2; Me, 3). The thiolate anion is easily exchanged by treatment with NaBPh4.
Synthesis and Reaction of Unsymmetrical Tetraarylbismuthonium Salts. First Isolation of Bismuthonium Salts Bearing All Different Aryl Groups
Authors: Matano Yoshihiro , Miyamatsu Takashi , Suzuki Hitomi
Published: March 2003

Successive treatment of triarylbismuth difluorides (1) with a Lewis acid, Me3SiCN, and aryltributylstannanes (2) in CH2Cl2 gives unsymmetrical tetraarylbismuthonium salts (3) in moderate to good yield. The migratory aptitude of an aryl ligand in [Ph3ArBi+][BF4−] (3a, b) in the C-arylation of 2-naphthol is Ph>p-Tol>p-Ans.
Effect of Lead Oxide Addition to the Photocatalytic Behavior of TiO2
Authors: Sakata Yoshihisa , Yamamoto Tomonori , Gunji Hideki , Imamura Hayao , Tsuchiya Susumu
Published: March 2003

The addition of small amount of lead oxide (less than 0.1 wt%) to TiO2 was effective for improving the photocatalytic activity of H2 production from aqueous methanol. By the addition of Pb2O3 to TiO2, the characteristic ability of photoassisted H2 production was observed under irradiation whose wavelength was longer than 420 nm and was appeared accompanied with the improvement of the photocatalytic activity.
Solid-Solid Catalysis by Ultrafine Crystallites of Heteropoly Compound for Pinacol Rearrangement
Authors: Toyoshi Yasuo , Nakato Teruyuki , Tamura Rui , Takahashi Hiroki , Tsue Hirohito , Hirao Ken-ichi , Okuhara Toshio
Published: March 2003

Cs2.5H0.5PW12O40 consisting of ultrafine crystallites efficiently catalyzes pinacol rearrangement of 1,1,2-triphenyl-1,2-ethanediol at room temperature in solid-solid reaction system, giving the corresponding aldehyde selectively, while p-toluenesulfonic acid, H-ZSM-5, HY, SiO2-Al2O3, SO42−/ZrO2 and Nb2O5 nH2O were inactive. The activity of Cs2.5H0.5PW12O40 in the solid-solid reaction was higher than that in solid-liquid (CHCl3) system.
A Microvoltammetric Study of Transport Process through a Nitrobenzene / Water Interface
Authors: Yamada Hiroshi , Akiyama Shin-ichi , Inoue Takenori , Koike Tohru , Matsue Tomokazu , Uchida Isamu
Published: March 2003

Transport of ferrocenylmethanol and Co(phen)32+ through a nitrobenzene/water interface was examined by an electrochemical method using a microelectrode. The transfer rate of Co(phen)32+ through nitrobenzene / water interface was determined to be 0.05 cm/s by digital simulation analysis. Transfer of ferrocenylmethanol was very fast, with the transfer rate estimated to be larger than 0.1 cm/s.
Synthesis of a Silylene- and Hydride-bridged Re-W Heterobimetallic Complex and Its Photolysis to Form Novel Silenyl-bridged Heterobimetallic Complexes
Authors: Sakaba Hiroyuki , Ishida Kazushige , Horino Hiroshi
Published: March 2003

The reaction of cis-Cp*W(CO)2(MeCN)Me (1) with Cp*(CO)2Re(H)SiMe2H (2) gave the silylene- and hydridebridged heterobimetallic complex Cp*(CO)2W(μ-SiMe2)(μ-H)Re(CO)2Cp* (3). Photolysis of 3 produced an isomeric mixture of novel silenyl-bridged heterobimetallic complexes Cp*(CO)2HW(μ-η1, η2-SiMeCH2)ReH(CO)2Cp* (4).
Activation of Sn-Se Bond: Regioselective Ring Opening Reaction of Epoxides with Tributylstannyl Phenylselenolate in the Presence of a Lewis Acid
Authors: Nishiyama Yutaka , Ohashi Hironori , Itoh Kazuyoshi , Sonoda Noboru
Published: March 2003

When tributylstannyl phenylselenolate (Bu3SnSePh) was allowed to react with epoxides in the presence of BF3·OEt2 as a Lewis acid, the ring opening reaction of epoxides proceeded with complete regioselectivity to afford the β-hydroxy phenylselenides in moderate to good yields.
Monolayers of Calix[4]resorcinarenes with Azobenzene Residues Exhibiting Efficient Photoisomerizability
Authors: Fujimaki Masanori , Matsuzawa Yoko , Hayashi Yuko , Ichimura Kunihiro
Published: March 2003

Azobenzenes tethered from the lower rim of crown conformer of O-octacarboxymethoxylated calix[4]resorcinarenes display efficient E-to-Z photoisomerizability in densely packed monolayers on a water surface, in LB films and in surface-adsorbed monolayers, respectively.
Two-Coordinate Gold(I) Aliphatic Thiolate Complex: The Au-S Distance Is Smaller than the Ag-S One
Authors: Fujisawa Kiyoshi , Imai Sadako , Moro-oka Yoshihiko
Published: March 2003

We prepared the first example of two-coordinate aliphatic monothiolate gold(I) complex. Its structural parameter was compared with that of copper(I) and silver(I) derivatives. The physical properties may be used to differentiate the coordination mode of gold(I) complexes.
Synthesis and Characterization of Triple-decker Sandwich Dinuclear La(III) and Lu(III) Complexes of 2,3,9,10,16,17,23,24-Octabutoxyphthalocyanine
Authors: Takahashi Kazuhiro , Shimoda Jun-ichi , Itoh Makoto , Fuchita Yoshio , Okawa Hisashi
Published: March 2003

The title complexes, [La2(obPc)3] (1) and [Lu2(obPc)3] (2) (H2obPc = 2,3,9,10,16,17,23,24-octabutoxyphthalocyanine), were obtained in a pure form and in good yields and characterized by means of mass, 1H NMR, and UV-visible (vis) spectroscopy and cyclic voltammetry.
Solvent Effect on Intramolecular Electron Transfer Rate of 1,3-Dinitrobenzene Radical Anion
Authors: Hosoi Haruko , Mori Yukie , Masuda Yuichi
Published: March 2003

The solvent induced intramolecular electron transfer rates of the 1,3-dinitrobenzene radical anion in acetonitrile and DMF were determined at various temperatures under negligible ion-ion interaction. For this purpose, a cryptand was used to capture the sodium counter cation, which was produced in the course of the chemical reduction of 1,3-dinitrobenzene. The obtained rates were ca. one order higher than those previously reported using an electrochemical reduction method with supporting electrolyte.
Synthesis of the High-valent Mn Porphyrin Species by Peroxy Acid Oxidation of MnIII Dimers. Characterization of the MnIV2 Species and Evidence of the MnV-MnIII Intermediate
Authors: Ichihara Kanako , Naruta Yoshinori
Published: March 2003

The MnIV porphyrin dimers were synthesized and characterized by UV-vis, ESI-MS, etc. Epoxidation of olefins indicated the transient formation of the MnV (=O) species, which were transformed into the MnIV species by the intramolecular comproportionation between MnV-MnIII moieties.
Controlled Growth of Polypyrrole Thin Films by Polymerization-induced Adsorption
Authors: Ichinose Izumi , Miyauchi Haruko , Tanaka Masayoshi , Kunitake Toyoki
Published: March 2003

Ultrathin polypyrrole films with a nanometer thickness were prepared by repeating adsorption of polypyrrole from the polymerization solution and washing with organic solvents. The thickness of the polypyrrole film linearly increased by using fresh polymerization mixtures at each adsorption step, as confirmed by quartz crystal microbalance and UV spectroscopy.
Reaction of a Zirconocene-Ethylene Complex with Group 14 Metal Chlorides or Alkoxides
Authors: Ura Yasuyuki , Hara Ryuichiro , Takahashi Tamotsu
Published: March 2003

A zirconocene-ethylene complex Cp2Zr(CH2=CH2)(PMe3) reacted with R3EX (E=Si, Ge, Sn; R=Ph or Bu; X=Cl, OEt, or OER3) to give R3EEt in high yields after hydrolysis. The reaction mixture of the ethylene complex with Bu3SnCl further reacted with phenylacetylene to give homoallyltin compounds. When the reaction mixture was treated with Ph3SnCl or Ph3GeCl instead of phenylacetylene, Ph3SnEt or Ph3GeEt was obtained in high yields after hydrolysis via the replacement of the β-SnBu3 moiety.
Effect of ZrO2 on the Stability of Cu-ZnO-ZrO2/HZSM-5 Catalyst for Syngas Conversion to Dimethyl Ether
Authors: Ge Qingjie , Huang Youmei , Li Shuben
Published: March 2003

The stability of Cu-ZnO/HZSM-5 and Cu-ZnO-ZrO2/HZSM-5 catalysts for syngas conversion to dimethyl ether has been evaluated using a fixed-bed flow microreactor at 290 °C, 40 atm, 1500 h−1. ZrO2 addition showed a marked improvement in the stability of catalyst.
Hydrolytic Function of a Hydroxo-ZnIIPbII Complex toward Tris-p-nitrophenyl Phosphate: A Functional Model of Heterobimetallic Phosphatases
Authors: Yamami Masako , Furutachi Hideki , Yokoyama Takushi , Okawa Hisashi
Published: March 2003

A ZnIIPbII complex ZnPb(L)(H2O)2(ClO4)2 of a macrocyclic compartmental ligand L2− is converted under alkaline conditions into a hydroxo complex ZnPb(L)(OH)(H2O)ClO4 that hydrolyzes tris-p-nitrophenyl phosphate (TNP) to bis-p-nitrophenyl phosphate (BNP−) forming a BNP-bridged complex [ZnPb(L)(BNP)]ClO4.
First Synthesis and Structure of Hexavalent Organic σ-Perselenurane Species (λ6-Selane): Bis(2,2′-biphenylylene)difluoroperselenurane [12-Se-6(C4F2)]
Authors: Sato Soichi , Arakawa Hiroshi , Horn Ernst , Furukawa Naomichi
Published: March 2003

Bis(2,2′-biphenylylene)selenurane (1; λ4-selane) reacts with xenon difluoride to give bis(2,2′-biphenylylene)difluoroperselenurane, [12-Se-6(C4F2)] (2; λ6-selane), which was analyzed by single crystal X-ray diffraction.
Preparation of New Fibrous Layered Compounds by the Reaction of Zinc Hydroxide with Organic Compounds
Authors: Ogata Sumikazu , Tasaka Yoshiharu , Tagaya Hideyuki , Kadokawa Jun-ichi , Chiba Koji
Published: March 2003

Organic-inorganic layered nano-hybrids were prepared by the reactions of amorphous Zn(OH)2 with organic oxychlorides and organic carboxylic acids, and fibrous layered compounds were obtained by the reaction with bulky organic compounds.
Reactions of Tetracyanoethylene Oxide (TCNEO) with Cobaltadithiolene Complexes
Authors: Takayama Chikako , Takeuchi Keiko , Kajitani Masatsugu , Sugiyama Toru , Sugimori Akira
Published: March 2003

The reactions of cobaltadithiolene complexes bearing phenyl or ester ligands with tetracyanoethylene oxide (TCNEO) result in the formation of dicyanomethylene-bridged complexes, via dicyanomethylide intermediates. Furthermore, the reaction of cobaltadithiolene complex bearing 4-pyridyl ligands produces pyridinium dicyanomethylide complexes in good yields.
Si X-Ray Absorption Near Edge Structure(XANES) in X-Ray Fluorescence Spectra
Authors: Kawai Jun , Hayashi Kouichi , Okuda Kazuaki , Nisawa Atsushi
Published: March 2003

Silicon K X-ray fluorescence spectra of Si and SiO2 single crystals are measured using a wave dispersive X-ray fluorescence spectrometer. It is demonstrated that the fine structures in the line shape of the low energy tail of the Kα characteristic X-ray fluorescence spectra resemble those of the K X-ray absorption near edge structure(XANES).
Catalysis by Solid Acid: Selective Diels-Alder Reactions Are Promoted by Mesoporous Aluminosilicate with Zinc Ions and Nanometer Honeycomb Openings
Authors: Onaka Makoto , Yamasaki Ryota
Published: March 2003

Zinc ion-exchanged mesoporous aluminosilicate has been designed specifically to accelerate the Diels-Alder reaction between cyclopentadiene and poor dienophiles such as methyl acrylate and methyl methacrylate. Catalysis on this aluminosilicate is more effective than on a K 10-based solid acid catalyst.
Synthesis and Helical Twisting Power of Optically Active 2-Methylchroman-2-carboxylic Acid Derivatives as New Chiral Dopants for Nematic Liquid Crystals
Authors: Shitara Hiroaki , Aoki Yoshio , Hirose Takuji , Nohira Hiroyuki
Published: March 2003

Optically active 2-methylchroman-2-carboxylic acid derivatives as new chiral dopants for nematic liquid crystals were prepared from optically active 6-benzyloxy-2-methylchroman-2-carboxylic acid, which was newly synthesized and resolved by diastereomeric salt formation method. The helical twisting power of the dopants was determined and the relationship with their structures were studied.
Platinum-added Sulfated-zirconia Effective for Highly Selective Dehydrogenative Coupling of Methane
Authors: Kurosaka Tadahiro , Matsuhashi Hiromi , Arata Kazushi
Published: March 2003

An active and stable catalyst of 3 wt% Pt-added sulfated-zirconia for the dehydrogenative coupling of methane is obtained by impregnating zirconia gel with 0.5 mol dm−3 H2SO4 followed by drying, impregnating the sulfated gel with a solution of H2PtCl6, calcining in air at 600 °C, and finally reducing in H2 at 500 °C; this catalyst gave 40% conversion of the equilibrium value with 100% selectivity at 500 °C.
Effects of Substituents on Silicon upon the Ring Inversion of Silepins Annelated with Bicyclo[2.2.2]octene Frameworks
Authors: Nishinaga Tohru , Izukawa Yoshiteru , Komatsu Koichi
Published: March 2003

The energy barrier for ring inversion of the silepin annelated with bicyclo[2.2.2]octene was found to decrease as the electro-negativity of substituents on silicon increases.
Extended Network via Axial Cu-Br Linkages of Zig-zag Coordination Chains of Copper(II) Ions Bridged Alternately by trans-Oxamidate and End-on Azide Groups
Authors: Chen Zhong-Ning , Zhang Hua-Xin , Yu Kai-Bei , Kang Bei-Sheng
Published: March 2003

The zig-zag coordination chains [Cu2(trans-oxen)(N3)(Br)]n[H2oxen=N,N′-bis(2-aminoethyl)oxamide] with alternating bridges of trans-oxamidate and azide in bis-terdentate and end-on mode, respectively, are held together via axial Cu-Br linkage in a unique fashion to form an extended structure.
A Mechanistic Study of Thermal and Photochemical Isomerization between Hexasilyltetrasilabicyclo[1.1.0]butane and Hexasilyltetrasilacyclobutene
Authors: Iwamoto Takeaki , Kira Mitsuo
Published: March 2003

Thermal isomerization of hexakis(t-butyldimethylsilyl)tetrasilabicylo[1.1.0]butane (2) to the corresponding tetrasilacyclobutene (1) as well as photochemical isomerization of 1 to 2 was confirmed using substituent-labeling experiments to proceed via 1,2-silyl-migration instead of skeletal isomerization.
Dielectrophoretic Separation of Single Microparticles with Quadrupole Microelectrode
Authors: Watarai Hitoshi , Sakamoto Takashi , Tsukahara Satoshi
Published: March 2003

In a microcell with a two-dimensional quadrupole microelectrode, polystyrene particles showed positive and negative dielectrophoresis (DEP) in lower (1 k-18 kHz) and higher (32 k-1 MHz) ac frequency regions, respectively, whereas only positive DEP was observed for carbon particles in a whole region of 1 k-1 MHz frequency. These findings were quantitatively explained by the difference in the conductivity of both particles. A DEP separation between the two kinds of particles was attained at a 1 MHz frequency.
Total Asymmetric Synthesis of Taxol by Dehydration Condensation between 7-TES Baccatin III and Protected N-Benzoylphenylisoserines Prepared by Enantioselective Aldol Reaction
Authors: Shiina Isamu , Saitoh Katsuyuki , Fréchard-Ortuno Isabelle , Mukaiyama Teruaki
Published: March 2003

Total asymmetric synthesis of Taxol was completed by dehydration condensation between a protected N-benzoylphenylisoserine 4 or 9 and 7-TES baccatin III which was prepared from 8-membered ring enone. Taxol side chains 4, 7, 9 and 11, optically active protected N-benzoylphenylisoserines, were successfully synthesized by enantioselective aldol reaction from two achiral starting materials, benzaldehyde and an enol silyl ether derived from S-ethyl benzyloxyethanethioate.
Unusual Formation of Cyclometallated C,H-trans-Hydridoruthenium(II) Complexes and Their Isomerization into C,H-cis-Types
Authors: Hiraki Katsuma , Koizumi Makoto , Kira Shu-ichi , Kawano Hiroyuki
Published: March 2003

The aromatic C-H bonds of N-benzylideneaniline and 2-phenylpyridine are cleaved by [RuH2(CO)(PPh3)3] and triethoxyvinylsilane at 70-110 °C to give the corresponding cyclometallated hydridoruthenium(II) complexes. The X-ray structure analyses of these complexes reveal that the hydrido ligand is initially situated trans to aryl group of the cyclometallated moiety and these two ligands are moved mutually into cis-sites by heating.
A Facile Synthesis of 1β-Methylcarbapenem Skeleton Utilizing Cyclization of α,β-Unsaturated Ester with Methanesulfenyl Chloride
Authors: Hayakawa Ryuuichirou , Fuseya Ichiro , Konagaya Tomohiro , Shimizu Makoto , Fujisawa Tamotsu
Published: March 2003

A facile synthetic route to 1β-methylcarbapenem skeleton is described utilizing cyclization of α,β-unsaturated ester with methanesulfenyl chloride.
Post-source Decay Fragment Analysis of a Highly Branched Nonasaccharide of Xyloglucan Using MALDI-TOF Mass Spectrometry
Authors: Yamagaki Tohru , Mitsuishi Yasushi , Nakanishi Hiroshi
Published: March 2003

A highly branched nonasaccharide of xyloglucan was analyzed by MALDI-TOFMS post-source decay fragment analysis. The fragmentation occurred only at glycosidic bonds at the non-reducing terminal side of the glycosidic oxygen. In the MALDI-PSD fragment spectrum, almost all fragment ions, possibly produced by a three-site cleavage, were observed. The large amount of fragment mass information allowed us to determine the sequentially fine structure of the highly branched oligosaccharide.
Novel Oxygen Sensor Based on Quenching of Triplet-Triplet Absorption of Zinc Tetraphenylporphyrin
Authors: Furuto Takao , Lee Sang-Kyung , Asai Keisuke , Okura Ichiro
Published: March 2003

A novel oxygen sensor based on the quenching of triplet-triplet absorption of zinc tetraphenylporphyrin (ZnTPP) molecules by oxygen has been developed. The excited triplet lifetime of ZnTPP-PS film decreases as increasing of oxygen concentration. This sensor showed linear Stern-Volmer plots and was capable of oxygen measurement.
Flaky, Ultrathin Mesoporous Silica Laminas
Authors: Singh Puyam S , Kosuge Katsunori
Published: March 2003

Flaky, ultrathin mesoporous silica laminas with uniform mesopores, have been synthesized by hydrolysis of acidic tetraethylorthosilicate solution with dodecylamine or, decylamine surfactant. The materials have BET surface areas of 600-850 m2/g and mesopore diameters of ca. 3-4 nm after the samples were calcined at 500 °C.
Synthesis of the Aglycon of Aurisides A and B, Cytotoxic Macrolide Glycosides of Marine Origin
Authors: Sone Hiroki , Suenaga Kiyotake , Bessho Yuhki , Kondo Takashi , Kigoshi Hideo , Yamada Kiyoyuki
Published: March 2003

The synthesis of the aglycon of aurisides A and B was achieved from (R)-pantolactone in 29 steps using the Nozaki reaction and the Yamaguchi macrolactonization as key steps.
Syntheses, Structures, and Insulin-like Activities of Two Vanadyl Complexes; [VO(GeG)(H2O)] and [VO(MeM)(H2O)]
Authors: Kawabe Kenji , Tadokoro Makoto , Kojima Yoshitane , Fujisawa Yae , Sakurai Hiromu
Published: March 2003

We prepared [VO(GeG)(H2O)] and [VO(MeM)(H2O)] by a reaction of VOSO4 with GeG and MeM. X-ray analyses of the complexes showed that a tetradentate ligand (GeG or MeM), an oxygen atom, and a water molecule were coordinated with the vanadium(IV) ion forming distorted octahedral geometries. In in vitro evaluation using isolated rat adipocytes, VO(GeG) (IC50=0.42 mM) was found to be more active at lower concentrations than VO(MeM)(IC50=17.0 mM) and VOSO4 (IC50=6.0 mM) in terms of IC50 values, 50% inhibition concentration of the FFA release from adipocytes.
Substituent Effects on the Chemiluminescent Properties of Coelenterazine Analogues
Authors: Saito Ryota , Hirano Takashi , Niwa Haruki , Ohashi Mamoru
Published: March 2003

Chemiluminescence maxima and quantum yields of coelenterazine analogues possessing a substituent R [=CF3, F, H, OCH3, OH, N(CH3)2] at the para-position on the 6-phenyl group were measured in DMSO. The result indicates that the variation of the electronic properties of R of these analogues caused the small change of the efficiency of chemical generation of a singlet excited light-emitter (Φs).
Novel Ring System with an Se–O–N Linkage: Synthesis and Crystal Structure of the First 1,2λ4,5-Oxaselenazolidine
Authors: Kano Naokazu , Nakanishi Nobuhito , Daicho Yuya , Kawashima Takayuki
Published: March 2003

Oxidation of β–aminoalkyl selenide 4a with an excess amount of mCPBA gave 1,2λ4,5-oxaselenazolidine 1, a novel heterocyclic compound with an Se–O–N linkage. Its X-ray crystallographic analysis revealed that the oxaselenazolidine ring has an envelope conformation.
Synthesis and Catalysis of Ti-MCM-41 Materials with Organic–Inorganic Hybrid Network
Authors: Yamamoto Katsutoshi , Nohara Yuki , Tatsumi Takashi
Published: March 2003

Ti-Containing MCM-41 materials were organically modified by employing an organosilane with a bridging organic group between two Si, and employed as catalysts for olefin oxidation using H2O2 as oxidant. The incorporation of a bridging organic group resulted in an increase in d spacing, in contrast to the modification with organosilane having terminal alkyl group, which provides decreased d spacing. High hydrophobicity of organically bridged Ti-MCM-41 materials led to high selectivity to epoxide by depressing allylic oxidation.
O2-Adduct Complex of meso-Tetrakis(α,α,α,α-o-pivalamidophenyl)porphinatoiron(II) with an Intramolecularly Coordinated Proximal Histidine
Authors: Komatsu Teruyuki , Matsukawa Yasuko , Miyatake Kaoru , Tsuchida Eishun
Published: March 2003

meso-Tetrakis(α,α,α,α-o-pivalamidophenyl)porphinatoiron(II) with an intramolecularly coordinated proximal histidine forms a stable O2-adduct complex in benzene solution at 25 °C; the O2-binding affinity (P1/2: 1.7 Torr) is significantly low compared to that of the N-alkylimidazole bound analogue.
Solvothermal Synthesis of NiS2−xSex Nanocrystallines
Authors: Wang Chunrui , Tang Kaibin , Yang Qing , An Changhua , Qian Yitai
Published: March 2003

NiS2−xSex nanocrystallines (0 ≤ x ≤ 2) was successfully synthesized by solvothermal method at 180–200 °C. It was found that both temperature and solvent have important effects on the formation of NiS2−xSex nanocrystallines.
Mechanochemical Synthesis of Ternary Fluorides with Perovskite Structures
Authors: Lee Jaeryeong , Zhang Qiwu , Saito Fumio
Published: March 2003

Mechanochemical synthesis of ternary zinc fluorides, AZnF3 (A = K, Na and NH4) with perovskite structures was attempted by grinding equimolar mixtures of zinc fluoride (ZnF2) and one of fluorides, i.e., potassium fluoride (KF), sodium fluoride (NaF) and ammonium fluoride (NH4F), respectively, in air using a planetary ball mill. The grinding enables us to synthesize these compounds, and the crystallinity of them is improved as the grinding progresses. The synthesized materials formed in the ground mixtures seem to be agglomerates of fine particles having diameters of about several tens nanometer.
Norbornene-Derived Quinizarin Dye Molecules for Photoimaging in Polymer Film Based on Chemical Amplification
Authors: Lee Jae-Hyoung , Cho Iwhan , Ahn Kwang-Duk , Kim Jong-Man
Published: March 2003

A novel photoimaging process in thin films has been disclosed by taking advantage of photolithographic techniques based on chemical amplification concept. The key materials utilized in the process are norbornene-derived quinizarin dye molecules protected with acid-labile tert-butoxycarbonyl (t-Boc) blocking groups.
Cellulose 3,5-Dimethylphenylcarbamate Immobilized onto Silica Gel via Copolymerization with a Vinyl Monomer and Its Chiral Recognition Ability as a Chiral Stationary Phase for HPLC
Authors: Kubota Takateru , Kusano Toshiya , Yamamoto Chiyo , Yashima Eiji , Okamoto Yoshio
Published: March 2003

A new cellulose phenylcarbamate derivative having a vinyl group at the 6-position was synthesized and immobilized onto silica gel via radical copolymerization with styrene. The immobilization was efficiently attained using a small amount of styrene. The chiral recognition abilities of the immobilized chiral stationary phase (CSP) were similar to those of the CSP coated on silica gel.
Ring-Opening Reactions of Alkanone Acetals with Iodosilane Equivalents for the Formation of Siloxyalkyl Enol Ethers
Authors: Ohshita Joji , Iwata Arihiro , Tang Heqing , Yamamoto Yasushi , Matui Chinami , Kunai Atsutaka
Published: March 2003

Reactions of ketone acetals with iodosilane equivalents were studied. Treatment of alkanone ethylene acetals with a 1:2 mixture of Et2NSiMe3 and MeI afforded 2-siloxyethyl enol ethers in good yield. Benzophenone ethylene acetal underwent deprotection with the iodosilane equivalents, giving benzophenone.
A Hexagonally Organized Elemental Supramolecular Structure of a Sugar-Appended Organogelator Observed by Synchrotron X-ray Source (SPring-8)
Authors: Sakurai Kazuo , Kimura Taro , Gronwald Oliver , Inoue Katsuaki , Shinkai Seiji
Published: March 2003

Small angle X-ray scattering from methyl 4,6-O-benzylidene-α-d-mannopyranoside/p-xylene organogels was carried out with a synchrotron X-ray source at SPring-8, which revealed that the molecules assemble in a hexagonally packed motif in the gel state and this supramolecular structure completely disappears in the sol state.
Remarkable Thiocarbonyl and Ring-Size Effects on the Amide Bond Twisting
Authors: Yamada Shinji , Matsuda Kaori
Published: March 2003

Remarkable thiocarbonyl and ring-size effects on the amide bond twisting were observed for N-acetylamides 1–3. The amide linkage of 2 is perpendicularly twisted, whereas the oxygen analog 1 and five-membered analog 3 are virtually planar, which were revealed by 13C NMR and IR spectroscopies, and X-ray analysis.
3-Picoline Oxidation over Monoclinic Orthovanadate Cr0.5Al0.5VO4 Catalysts
Authors: Zhaoxia Song , Kadowaki Eriko , Shishido Tetsuya , Wang Ye , Takehira Katsuomi
Published: March 2003

Monoclinic orthovanadate CrVO4-I was found to be active for the vapor phase oxidation of 3-picoline to nicotinic acid and was further activated by the solid solution formation with Al at the Cr site.
New Negative-Type Photosensitive Polyimide Based on Hyperbranched Poly(ether imide), a Cross-Linker, and a Photoacid Generator
Authors: Okazaki Masaki , Shibasaki Yuji , Ueda Mitsuru
Published: March 2003

A new negative working photosensitive polyimide, based on hyperbranched poly(ether imide) (1), 4,4′-methylenebis[2,6-bis(hydroxymethyl)]phenol (2) as a cross-linker, and a photoacid generator diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (3) has been developed. 1 was prepared by polycondensation of N-[3,5-di-(tert-butyldimethylsilyloxy)phenyl]-4-fluorophthalimide (4), followed by deprotection of tert-butyldimethylsilyl group with KF-HBr. The photosensitive polyimide containing 1 (70 wt%), 2 (20 wt%) and 3 (10 wt%) gave a clear negative pattern when it was exposed to 365 nm light and postbaked at 120 °C, followed by developing with a 2.38 wt% aqueous tetramethylammonium hydroxide (TMAH) solution at room temperature.
Preparation and Properties of a Huge, Crystalline, and Water-Soluble Compound (C72H132N12Br6S12) That Possesses Six Carbenium Salt Units
Authors: Nakayama Juzo , Otani Toyohiro , Tadokoro Tomoko , Sugihara Yoshiaki , Ishii Akihiko
Published: March 2003

The reaction of hexakis(bromomethyl)benzene with six molar amounts of 2,2-bis(diethylamino)-2-ethylium-1-dithiocarboxylate furnished a huge, crystalline, and water-soluble compound (C72H132N12Br6S12, MW = 2030) that possesses six carbenium bromide units.
Solvothermal Synthesis to Nanocrystalline Ni0.85Se and NiSe2 at Low Temperature
Authors: Meng Zhaoyu , Peng Yiya , Xu Liqiang , Yu Weichao , Qian Yitai
Published: March 2003

Nanocrystalline Ni0.85Se and NiSe2 were prepared through the reaction between NiCl2·6H2O and elemental selenium at 50 °C, using N2H4·H2O as reductant and pyridine as solvent. TEM images showed that the Ni0.85Se and NiSe2 particles were both spherical in shape with sizes of about 20 nm. Solvent pyridine plays an important role in the formation of nanocrystalline nickel selenides due to its appropriate N-chelation ability and alkalescence.
Stellate Macroscopic Crystals from Cationic and Anionic Porphyrins
Authors: Yamaguchi Hiroyasu , Harada Akira
Published: March 2003

Mixing tetrasodium [meso-tetrakis(4-sulfonatophenyl)porphinato]zinc (Zn-TSPP) and meso-tetrakis(4-(trimethylammonio)phenyl)porphine tetratosylate (TTMAPP) in dimethylsulfoxide leads to formation of a star-like (stellate) microcrystal.
Stabilization of Superionic α-AgI at Room Temperature by Heating of AgI−Ag2O−MoO3 Glasses
Authors: Tatsumisago Masahiro , Saito Taira , Minami Tsutomu
Published: March 2003

We successfully prepared the superionic composites in which only the high-temperature phase of α-AgI was stabilized at room temperature in a superionic glassy matrix by a simple procedure with heating and consecutive cooling of AgI−Ag2O−MoO3 glasses. In the composites, α-AgI microcrystals were dispersed in the glassy matrix.
Fluorescence Sensing Behavior of Crystals of an Imidazole-Type Clathrate Host upon Contact with Gaseous Carboxylic Acids
Authors: Yoshida Katsuhira , Uwada Kazuki , Kumaoka Hironori , Bu Lequan , Watanabe Shigeru
Published: March 2003

The crystals of the title fluorescent clathrand exhibit a drastic fluorescence enhancement behavior upon contact with carboxylic acid vapors. The magnitude of the fluorescence change is greatly dependent on the enclathrated carboxylic acid molecules and increase in the following order: formic acid < acetic acid < propionic acid. To elucidate the enclathrated guest effects on the fluorescence properties of the crystals, the X-ray crystal structures have been determined.
Control of C–C and C–N Bond Cleavage of 2H-Azirine by Means of the Excitation Wavelength: Studies in Matrices and in Solutions
Authors: Inui Hiroshi , Murata Shigeru
Published: March 2003

The remarkable wavelengh-dependent photoreactions of 3-methyl-2-(1-naphthyl)-2H-azirine (1) were observed in matrices at 10 K and in solutions at room temperature. Irradiation of 1 with the long-wavelength light (366 nm) exclusively gave the products formed by the cleavage of the C–N bond of the 2H-azirine ring, while the products derived from the C–C bond cleavage were predominantly obtained in the irradiation with the short-wavelength irradiation (>300 nm).
Synthesis and Photodynamic Therapy Properties of a Water-Soluble Hypocrellin Modified by Cyclodextrin
Authors: Ou Zhi-Ze , Chen Jing-Rong , Wang Xue-Song , Zhang Bao-Wen , Cao Yi
Published: March 2003

For improving water solubility of hypocrellin B (HB), a cyclodextrin modified hypocrellin B (HBCD) was designed and synthesized. Electron spin resonance (ESR) measurement indicated that this HB derivative remained photodynamically active in terms of type I and type II mechanisms. HBCD is water-soluble and possesses stronger photosensitized damage ability to calf thymus DNA than hypocrellin B.
Di- and Trinuclear Nickel(II) Complexes Containing Tripodal Hexadentate Ligands
Authors: Ohta Hiromi , Harada Kenji , Irie Koji , Kashino Setsuo , Kambe Takashi , Sakane Genta , Shibahara Takashi , Takamizawa Satoshi , Mori Wasuke , Nonoyama Matsuo , Hirotsu Masakazu , Kojima Masaaki
Published: March 2003

The reaction of Ni2+ with a tripodal hexadentate ligand (H3L = 1,1,1-tris(N-salicylideneaminomethyl)ethane) afforded the O–H···O bridged dinuclear [Ni2(HL)2] complex. When Ni2+ was allowed to react with H3L in the presence of triethylamine (3 : 2 : 6), the linear trinuclear [Ni3(L)2] complex formed, where the central nickel(II) ion is bridged by six phenolate oxygen atoms to the terminal nickel(II) ions.
EPR Study of Cu(II) in N-Terminal Lobe Fragment of Hen Ovotransferrin
Authors: Kawabata Teruyuki , Fujisawa Masayoshi , Hida Akira I , Okada Shigeru
Published: March 2003

The N-terminal lobe fragment of hen ovotransferrin was prepared by trypsin digestion and the following gel filtration and ion-exchange chromatography. EPR spectra of Cu(II) complex of the N-terminal fragment were recorded independently from the C-terminal lobe and a major spectrum of the copper(II) complex showed g// = 2.300 and g⊥ = 2.061 with ACu// = 14.0 mT, ACu⊥ = 2.20 mT, which had a superhyperfine splitting (AN⊥ = 1.44 mT) of a nitrogen ligand, which may correspond to type A-1 site of copper binding position in the N-terminal lobe of hen ovotransferrin.
A Novel Lanthanide–Transition Metal Complex Constructed by Orotic Acid
Authors: Sun Daofeng , Cao Rong , Liang Yucang , Hong Maochun
Published: March 2003

Hydrothermal reaction of Cu(CH3COO)2·5H2O and NdCl3·6H2O with orotic acid (2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid, H3dtpc) in water gave rise to a novel polymeric complex, [Nd2Cu3(Hdtpc)6(H2O)4]n, with two-dimensional layer structure. Nd(III) atom is nine-coordinated by nitrogen and oxygen atoms of Hdtpc ligands and water molecules and Cu(II) atom is four-coordinated by two chelated Hdtpc in a square planar geometry. The hydrogen bond interactions among layers lead to the formation of three-dimensional network structure.
An Efficient and Mild Procedure for the Preparation of Benzoic Acids via Oxidation of Aromatic Carbonyl Compounds by Employing N-Bromoimides and Mercuric Acetate System
Authors: Anjum Amena , Srinivas P
Published: March 2003

Aromatic carbonyl compounds are efficiently converted into the corresponding benzoic acids under mild reaction conditions by employing N-bromoimide and mercuric acetate in good to excellent yields. This procedure works efficiently at room temperature for aromatic aldehydes as well as aromatic ketones to give the corresponding benzoic acids.
Self-Assembly of a Novel Infinite Triple Helices Coordination Polymer {[Co(4,4′-bipyridine)(4,4′-azobispyridine)2(NCS)2]·H2O}n via Hydrogen-Bonding Interaction
Authors: Li Baolong , Liu Huibiao , Xu Yan , Chen Jietong , Xu Zheng
Published: March 2003

The novel complex {[Co(bpy)(azpy)2(NCS)2]·H2O}n (where bpy = 4,4′-bipyridine, azpy = 4,4′-azobispyridine) comprising unprecedented three parallel interpenetrating two-dimensional (4,4) networks and forming novel infinite triple helices via hydrogen-bonding interaction, has been synthesized and characterized.
Highly Stereoselective 7-Membered Ring Synthesis Based upon the Oxidopyrylium–Alkene [5+2]Cycloaddition Reaction
Authors: Ohmori Naoki , Miyazaki Toru , Kojima Satoshi , Ohkata Katsuo
Published: March 2003

The [5+2]cycloaddition reaction of 2-substituted-3-oxidopyrylium betaine with dialkyl fumarates was found to proceed with stereoselectivity up to 15.5 : 1. The stereoselectivity became higher as either the 2-substituent of the 3-oxidopyrylium or the alkoxy group of the fumarate became larger. The stereoselectivity could be rationalized by considering these steric effects.
ZnO Marker for a Radio Frequency ESR Spectrometer
Authors: Ito Tomohiro , Sugawara Michio , Ogata Tateaki
Published: March 2003

The marker for quantitative determination of free radicals by a radio frequency (RF) electron spin resonance (ESR) spectrometer operating at about 700 MHz was found for the first time. It is zinc(II) oxide (ZnO) with the ESR signal due to oxygen vacancy. The g-value was about 1.96 and also the line shape was sharp. When this marker was measured together with TEMPOL aqueous solution by using the RF ESR spectrometer, each signal did not overlap. Furthermore, the signal intensity ratio of TEMPOL to ZnO unchanged even if Q-value of a resonator was decreased.
Crystallization of Calcium Oxalate in Liposome Solutions of Different Carboxylates
Authors: Ouyang Jian-Ming , Duan Li , He Jian-Hua , Tieke Bernd
Published: March 2003

The effects of tri-, di- and monocarboxylate on the growth of nanoparticles of calcium oxalate (CaOxa) were first investigated in liposome system. Sodium acetate (NaAc) only induced calcium oxalate monohydrate (COM), while sodium tartrate (Na2tart) and sodium citrate (Na3cit) could induce calcium oxalate dihydrate (COD) with a preferential growth of (213) crystal face. The promotion effectiveness to COD followed this order: Na3cit > Na2tart > NaAc.
Sequential Carbometalation/Elimination Reaction Takes Place between Gallium Enolate and Chloroethyne
Authors: Amemiya Ryo , Fujii Akiko , Arisawa Mieko , Yamaguchi Masahiko
Published: March 2003

In the presence of GaCl3, silyl enol ethers are sequentially ethynylated at the α-carbon atom with chlorotrimethylsilylethyne giving α-enynylated, α-endiynylated and α-entriynylated ketones.
Temperature Effect on Layer-by-Layer Self-assembly of Linear Polyions and Silica Multilayers
Authors: Shi Jingshi , Hua Feng , Cui Tianhong , Lvov Yuri M
Published: March 2003

Alternate layer-by-layer self-assembly of linear polyions and colloidal silica at elevated temperatures has been investigated by QCM and SEM. A growth step at 90 °C for these multilayers was about 100–200% larger than the one at 20 °C.
7,7-Dicyano-8,8-bis[4-(N,N-dimethylamino)phenyl]-meta-xylylenes: The First Stable Zwitterionic Metaxylylene Derivatives
Authors: Kawase Takeshi , Iwata Tohru , Oda Masaji
Published: March 2003

Treatment of 3-lithiophenyldicyanomethide ions with Michler’s ketone afforded the title compounds as stable crystals upon weak-acidic work-up. The molecular structure and spectroscopic data reveal the zwitterionic nature of the compounds.
An Open-framework Zincophosphate with Intersecting Channels
Authors: Zhao Yongnan , Son Jung-Ho , Kwon Young-Uk
Published: March 2003

An open-framework zincophosphate has been synthesized under hydrothermal conditions; its structure is constructed by PO4, ZnO4 and ZnO6 groups; the linkage of PO4 and ZnO4 give rise to a sheet structure that is pillared by ZnO6 forming a two-dimensional intersecting channel system.
Thin Silica Film with a Network Structure as Prepared by Surface Sol-Gel Transcription on the Poly(styrene-b-4-vinylpyridine) Polymer Film
Authors: Fujita Norifumi , Otsuka Hideyuki , Takahara Atsushi , Shinkai Seiji
Published: March 2003

Sol-gel polycondensation of tetraethyl orthosilicate (TEOS) was carried out on the cast film of poly(styrene-b-4-vinylpyridine) under basic (benzylamine), acidic (AcOH), and neutral (no catalyst) conditions. It was found that only under the acidic and neutral conditions, the phase-separated periodic structure of the copolymer is finely transcribed into the silica. This is a new, convenient method to create the thin, mosaic film from inorganic materials.
Use of 111In–L–LDL radiotracers to detect human pancreatic and mice melanoma tumors
Authors: Urizzi Pascale , Souchard Jean‐Pierre , Ratovo Ginette , Coulais Yvon , Nepveu Françoise , Hollande Etienne
Published: March 2003

The present study was designed to evaluate the potential of labeled low‐density lipoprotein with 111In using a lipid chelating agent (bis(stearylamide) of diethylenetriaminepentaacetic acid: L) to detect pancreatic tumors and melanoma in mice by gamma‐scintigraphy. We compare the biodistribution of radioactivity and scintigraphic images in nude mice heterotransplanted with human cancerous pancreatic duct cells (Capan‐1) and in mice transplanted with murine tumor cells (B16 melanoma). Biodistribution studies showed that radioactivity was twice as high in the Capan‐1 xenograft after injection of the radiolabel than after injection of radiometal alone, and 34‐fold higher in the B16 tumor. On gamma‐scintigraphic imaging, the Capan‐1 tumor was just visible, whereas the B16 melanoma was clearly imaged. The lack of contrast of the Capan‐1 tumor compared with the B16 melanoma could be due to a poor vascularization. Copyright © 2003 John Wiley & Sons, Ltd.
Non‐Metathetic Behavior Patterns of Grubbs' Carbene
Authors: Alcaide Benito , Almendros Pedro
Published: March 2003

Grubbs' carbene complex [Cl2(Cy3P)2RuCHPh] and its second‐generation counterpart [Cl2(Im)(Cy3P)RuCHPh] have demonstrated remarkable efficiency metathesizing olefins. Furthermore, a growing number of newly discovered catalytic processes mediated by this complex broaden its synthetic utility beyond olefin metathesis. In addition, the ready availability of these stable ruthenium‐based catalysts coupled with their tolerance toward a wide variety of common functional groups make Grubbs' catalysts very convenient synthetic tools. This paper presents recent advances in the non‐metathetic behavior patterns of Grubbs' carbene.
Total Synthesis of Mannosyl Tryptophan and Its Derivatives
Authors: Manabe Shino , Marui Yoshihiko , Ito Yukishige
Published: March 2003

Glycosylation is one of the most important post‐ or co‐translational modifications of proteins, which affects the biological activities of the parent proteins by influencing the higher‐order structure. Recently, a highly novel variant of glycoproteins that incorporate a C‐glycosylated amino acid was identified in various proteins. The total synthesis of one such C‐glycosyl amino acid, namely, C 2‐α‐D‐C‐mannosylpyranosyl‐L‐tryptophan and related peptides were successfully achieved. The mannose and tryptophan moieties were connected via ring opening of benzyl‐protected 1,2‐anhydro‐mannose by a lithiated indole derivative. After the functional group conversion and deprotection steps, the glyco‐amino acid was synthesized in a concise and stereoselective manner, in high overall yields. The stereoisomer, C 2‐α‐D‐C‐glycosylpyranosyl‐L‐tryptophan was synthesized in a similar way. Furthermore, it was revealed that the intermediate azido acid can serve as a useful building block for peptide elongation. A synthetic route for the peptide bond formation of a glycopeptide, without protection of the hydroxyl groups, using the triazine salt derivative as a coupling reagent is also reported.
Synthesis of Perfluoroalkyl‐Substituted Bis(oxazolines) as Ligands for Catalytic Enantioselective Reactions
Authors: Annunziata Rita , Benaglia Maurizio , Cinquini Mauro , Cozzi Franco , Pozzi Gianluca
Published: March 2003

Two chiral perfluoroalkyl‐substituted bis(oxazolines) (F‐box) have been prepared for the first time by a reaction sequence that involved formation of the properly functionalized box followed by introduction of two (ligand 9) or four (ligand 6) n‐C8F17 residues. The fluorine content of these F‐box was 49.2 and 55.5%, respectively. These ligands were employed in the ene reaction between α‐methylstyrene and ethylglyoxalate carried out in the presence of [Cu(OTf)2] (up to 67% ee), and in the cyclopropanation of styrene in combination with CuOTf (up to 78% ee). In both cases the F‐box with the lower fluorine content performed better than the more fluorinated one in terms of chemical yield and enantioselectivity. Ligand 9 was recovered by flash chromatography; ligand 6 by phase separation of the reaction solvents. Comparisons between the use of perfluoroalkyl groups and of soluble and insoluble polymers as solubility devices for the recovery and recycling of the bis(oxazoline) ligand are also reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Cover Picture: Titanium‐Mediated Carboxylation of Alkynes With Carbon Dioxide (Eur. J. Org. Chem. 7/2003)
Authors: Six Yvan
Published: March 2003

The cover picture shows the titanium‐mediated carboxylation of alkynes. A titanacyclopropene intermediate is generated by a ligand exchange reaction. This species reacts with carbon dioxide to give a five‐membered complex, which can be trapped with various electrophiles. Tri‐ or tetra‐substituted vinylcarboxylic acids of well‐defined stereochemistry and butenolides are thus obtained. In the course of this work, a practical procedure was developed for the preparation of (η2‐cyclopentente)diisopropyloxytitanium, which was also shown to react with carbon dioxide. Details are discussed in the article by Y. Six on p. 1157 ff.
First Intramolecular Aglycon Delivery onto a D‐Fucofuranosyl Entity for the Synthesis of α‐D‐Fucofuranose‐Containing Disaccharides
Authors: Gelin Muriel , Ferrières Vincent , Lefeuvre Martine , Plusquellec Daniel
Published: March 2003

Intramolecular aglycon delivery was performed for the first time starting from n‐pentenyl glycofuranoside as a donor. p‐Methoxybenzyl‐assisted aglycon transfer required very mild reaction conditions and was promoted by N‐iodosuccinimide without assistance of any Lewis acid catalyst. As a result, rare α‐D‐fucofuranose‐containing disaccharides were obtained. Moreover, structure elucidation led to the conclusion that an N‐succinimidyl residue was still present in the resulting products. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Structurally diagnostic ion–molecule reactions: acylium ions with α‐, β‐ and γ‐hydroxy ketones
Authors: Moraes L. A. B. , Eberlin Marcos N.
Published: March 2003

Gas‐phase reactions of four acylium ions and a thioacylium ion with three isomeric α‐, β‐ and γ‐hydroxy ketones are performed by pentaquadrupole mass spectrometric experiments. Novel structurally diagnostic reactions are observed, and found to correlate directly with interfunctional group separation. All five ions tested (CH3CO+, CH2CHCO+, PhCO+, (CH3)2NCO+ and (CH3)2NCS+) react with the γ‐hydroxy ketone (5‐hydroxy‐2‐pentanone) to form nearly exclusively a cyclic oxonium ion of m/z 85 that formally arises from hydroxy anion abstraction. With the β‐hydroxy ketone (4‐hydroxy‐2‐pentanone), CH2CHCO+, PhCO+ and (CH3)2NCO+ form adducts that undergo fast cyclization via intramolecular water displacement, yielding resonance‐stabilized cyclic dioxinylium ions. With the α‐hydroxy ketone (3‐hydroxy‐3‐methyl‐2‐butanone), PhCO+, (CH3)2NCO+ and (CH3)2NCS+ form stable adducts. Evidence that these adducts display cyclic structures is provided by the triple‐stage mass spectra of the (CH3)2NCS+ adduct; it dissociates to (CH3)2NCO+ via a characteristic reaction–dissociation pathway that promotes sulfur‐by‐oxygen replacement. If cyclizations are assumed to occur with intramolecular anchimeric assistance, relationships between structure and reactivity are easily recognized. Copyright © 2001 John Wiley & Sons, Ltd.
Automated deconvolution and deisotoping of electrospray mass spectra
Authors: Wehofsky Marco , Hoffmann Ralf
Published: March 2003

Electrospray ionization (ESI) of peptides and proteins produces a series of multiply charged ions with a mass/charge (m/z) ratio between 500 and 2000. The resulting mass spectra are crowded by these multiple charge values for each molecular mass and an isotopic cluster for each nominal m/z value. Here, we report a new algorithm simultaneously to deconvolute and deisotope ESI mass spectra from complex peptide samples based on their mass‐dependent isotopic mean pattern. All signals corresponding to one peptide in the sample were reduced to one singly charged monoisotopic peak, thereby significantly reducing the number of signals, increasing the signal intensity and improving the signal‐to‐noise ratio. The mass list produced could be used directly for database searching. The developed algorithm also simplified interpretation of fragment ion spectra of multiply charged parent ions. Copyright © 2002 John Wiley & Sons, Ltd.
Characterization of geometrid sex pheromones by electrospray ionization time‐of‐flight mass spectrometry
Authors: Yamazawa Hiroyuki , Yamamoto Masanobu , Karasawa Kaoru Iida , Pu Guan‐Qin , Ando Tetsu
Published: March 2003

The utility of liquid chromatography combined with time‐of‐flight mass spectrometry (LC/TOFMS) was demonstrated for studies on chiral unsaturated epoxy compounds, sex pheromones produced mainly by female moths in the family Geometridae. By electrospray ionization (ESI), each synthetic epoxyalkadiene derived from (Z,Z,Z)‐3,6,9‐triene with a C18–C23 straight chain showed three ion series, [M + NH4]+, [M + H]+ and [M − OH]+, with high resolution and good sensitivity, indicating its molecular formula. In addition to these, characteristic fragment ions at m/z M − 57 and M − 71 for the 3,4‐epoxides and at m/z M − 123 and 123 for the 9,10‐epoxides were detected, whereas the 6,7‐epoxides did not produce fragment ions that reflected their structures. Monitoring these diagnostic ions during the LC/MS analysis of a gland extract, the natural sex pheromone of the mulberry looper was confirmed to be (Z,Z)‐cis‐9,10‐epoxy‐3,6‐octadecadiene, which was separable from the other positional isomers on an ODS column. Furthermore, (Z,Z)‐cis‐3,4‐epoxy‐6,9‐nonadecadiene secreted by the Japanese giant looper was analyzed with a chiral column, and the stereochemistry was determined directly. Copyright © 2003 John Wiley & Sons, Ltd.