bluuebunny/crossref_metadata_2025 huggingface dataset:
BF3‐Promoted Reactions of Cyclic 1,2‐Diketones and Paraformaldehyde − New Structural Motifs by Multiple Hydroxymethylation and Acetal Formation
Authors: Löbel Johannes , Herdtweck Eberhardt , Bach Thorsten
Published: October 2003

The BF3‐promoted reaction of paraformaldehyde with the cyclic 1,2‐diketones1,3,8and10was studied. Under identical reaction conditions, the substrates yielded structurally different products depending on their ring size. 1,2‐Cyclopentanedione (3a) was converted into the spiro compound4(49%) whereas its 3‐methyl analog3bgave a butterfly‐like compound5b(56%). A structurally related compound2was obtained (84%) by the reaction of 1,2‐cyclohexanedione (1) with paraformaldehyde. 1,2‐Cycloheptanedione (8) yielded the simple tricyclic acetal9(72%) whereas 1,2‐cyclooctanedione (10) underwent a twofold hydroxymethylation in the α‐ and α′‐positions yielding the acetal11(53%). The structures of all new compounds were proven by NMR experiments and X‐ray crystallography. The mechanism of product formation is discussed based on steric and electronic arguments. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Preparation of N‐Glycosylhydroxylamines and Their Oxidation to Nitrones for the Enantioselective Synthesis of Isoxazolidines
Authors: Cicchi Stefano , Marradi Marco , Corsi Massimo , Faggi Cristina , Goti Andrea
Published: October 2003

N‐benzyl‐ and N‐methyl‐N‐glycosylhydroxylamines 3a−i were conveniently obtained by reaction of sugars with N‐substituted hydroxylamines according to a novel procedure. Subsequent oxidation occurred at the alkyl group, selectively affording the corresponding C‐phenyl‐ and C‐unsubstituted N‐glycosylnitrones. C‐phenyl‐N‐glycosylnitrones 10 and 13 underwent highly stereoselective 1,3‐dipolar cycloaddition with dimethyl maleate, with the sugar moiety acting as a chiral auxiliary. Final removal of the glycosyl moiety afforded enantiopure enantiomeric isoxazolidines 17 and ent‐17 which are oxa‐analogues of proline diester derivatives. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Pyridyl Phosphinites and Pyridyl Phosphites from Chiral Pyridyl Alcohols — A Modular Approach
Authors: Rahm Fredrik , Fischer Andreas , Moberg Christina
Published: October 2003

Chiral arylated pyridyl alcohols, pyridyl phosphinites and pyridyl phosphites were prepared by Suzuki arylation and/or O‐functionalization with a chlorodiarylphosphane or a chlorodiarylphosphite of chiral 2‐bromo‐6‐(1‐hydroxyalkyl)pyridines or 2‐(1‐hydroxyalkyl)pyridines, with the chirality originating from the chiral pool. The pyridyl alcohols were assessed as catalysts for the addition of diethylzinc to benzaldehyde and the P,N‐ligands were employed in the palladium‐catalysed substitutions of rac‐1,3‐diphenyl‐2‐propenyl acetate and rac‐2‐cyclohexenyl acetate with dimethyl malonate. Moderate enantioselectivities were observed in the catalytic reactions. We observed kinetic resolution of the racemic acetate when using one of the phosphite ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Pd‐Assisted Multicomponent Synthesis of Heterocycles
Authors: Balme Geneviève , Bossharth Emmanuel , Monteiro Nuno
Published: October 2003

This review highlights some remarkable recently made achievements in the application of palladium‐mediated processes to the design of multicomponent one‐pot syntheses of heterocyclic compounds. Palladium‐catalysed cascade reactions are surveyed, together with processes based on sequential, one‐pot performance of individual transformations in which at least one is catalysed by palladium. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
A Photophysical and Electrochemical Investigation on a Phenylacetylene Macrocycle Containing Two 2,2′‐Bipyridine Units, Its Protonated Forms, and RuII and OsII Complexes
Authors: Venturi Margherita , Marchioni Filippo , Balzani Vincenzo , Opris Dorina M. , Henze Oliver , Schlüter A. Dieter
Published: October 2003

The phenylacetylene macrocycle 1, which incorporates two 2,2′‐bipyridine (bpy) chelating units in opposite sites in its shape‐persistent structure, shows an intense absorption band in the UV spectral region (λmax = 305 nm, ϵmax = 118000 M−1cm−1) and a very strong fluorescence band in dichloromethane solution (λmax = 381 nm, τ = 0.8 ns, Φ = 0.9). Upon titration with trifluoromethanesulfonic acid, the two bpy units are independently protonated with formation of a [1.2H]2+ species that shows a new absorption band with λmax = 355 nm (ϵmax = 42000 M−1cm−1) and a weak fluorescence (λmax = 520 nm). The dinuclear [(bpy)2Ru(1)Ru(bpy)2]4+ and [(bpy)2Os(1)Os(bpy)2]4+ complexes do not show any ligand‐centred emission and exhibit absorption and emission bands in the visible region {[(bpy)2Ru(1)Ru(bpy)2]4+, absorption: λmax = 453 nm, ϵmax = 19000 M−1cm−1; emission: λmax = 625 nm, τ = 792 ns, Φ = 0.05; [(bpy)2Os(1)Os(bpy)2]4+ absorption: λmax = 488 nm, ϵmax = 15500 M−1cm−1; emission: λmax = 740 nm, τ = 59 ns, Φ = 0.003}. The photophysical behaviour of the macrocyclic ligand 1 and the dinuclear complexes at 77 K has also been investigated. The electrochemical properties of 1, the model compound ligand 3 and bpy ligand were investigated in purified tetrahydrofuran under vacuum conditions. The electrochemical behaviour of the dinuclear complexes was studied in argon‐purged dichloromethane and compared with that of the model compounds [Ru(bpy)2(3)]2+, [Ru(bpy)3]2+, and [Os(bpy)3]2+. In the dinuclear complexes the two metal centres and the two 2,2′‐bipyridine units of macrocycle 1 behave independently, as shown by the reversible bielectronic processes observed on oxidation and reduction. Both 1 and its dinuclear complexes contain reactive substituents and can therefore be used as starting components for the construction of photo‐ and redox‐active supramolecular species. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
New Diastereoselective Route to 2‐Substituted cis‐(2S,5S)‐ and trans‐(2S,5R)‐5‐Alkylpyrrolidines as Indolizidine and Pyrrolizidine Scaffolds
Authors: Mota Antonio J. , Chiaroni Angèle , Langlois Nicole
Published: October 2003

A new and short stereoselective route to the synthesis of enantiopure cis‐2,5‐disubstituted pyrrolidines as indolizidine or pyrrolizidine scaffolds has been developed. The method, which uses (S)‐pyroglutamic acid as a chiral starting material, is based on the ring opening of N‐protected γ‐lactams by alkyl phenyl sulfone carbanions, followed by desulfonylation and reductive amination of alkyl γ‐amino ketones. The diastereoselectivity depends on the substitution of the starting γ‐lactams, and on the alkyl group of the phenyl sulfone. Total cis diastereoselectivity was observed in the formation of tert‐butyl 5‐alkylprolinates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis and Reactions of (2,2,2‐Trifluoroethyl)triphenylphosphonium Trifluoromethanesulfonate
Authors: Hanamoto Takeshi , Morita Noriko , Shindo Keiko
Published: October 2003

(2,2,2‐Trifluoroethyl)triphenylphosphonium trifluoromethanesulfonate (triflate) (1) was readily synthesized in high yield from triphenylphosphane and 2,2,2‐trifluoroethyl triflate. The Wittig olefination of 1 with aromatic aldehydes bearing electron‐withdrawing groups with CsF as a base in DMF proceeded cleanly, producing the corresponding 3,3,3‐trifluoropropenylidene compounds in good yields. On the other hand, the hydrolysis of 1 in methanol containing sodium hydroxide gave (2,2‐dimethoxyvinyl)triphenylphosphonium triflate (6a) in high yield instead of the corresponding (2,2,2‐trifluoroethyl)diphenylphosphane oxide. Furthermore, reactions between 1 and secondary amines exclusively gave the novel (Z)‐(2‐amino‐2‐fluorovinyl)triphenylphosphonium triflates (10) in high yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis of Racemic and Enantiomerically Pure (R*,R*,R*)‐Tris(α‐methylbenzyl)phosphane − X‐ray Crystal Structures of the Phosphane Oxides and Borane Complexes
Authors: Wyatt Paul , Eley Helen , Charmant Jonathan , Daniel Berian J. , Kantacha Anob
Published: October 2003

An asymmetric synthesis of C3‐symmetric phosphane 1 has been achieved. Two of the α‐methylbenzyl groups were introduced as nucleophiles (using an α‐methylbenzyl Grignard reagent), and asymmetry was introduced by resolution using (R)‐α‐methylbenzylamine. The final α‐methylbenzyl group was introduced as an electrophile (α‐methylbenzyl iodide) in a modestly selective reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Solid‐Phase Synthesis of Dihydropyrans by Heterocycloaddition of a Supported Vinyl Ether: Progress in Functional Diversity
Authors: Arboré Amélie , Dujardin Gilles , Maignan Christian
Published: October 2003

The carboxypolystyrene‐bound vinyl ether of 1,4‐butanediol smoothly underwent an efficient endo‐selective hetero‐Diels−Alder reaction, under Lewis‐acid conditions, with heterodienes bearing methyl ester, trifluoromethyl and para‐tolylsulfinylmethyl groups at the C‐2 position. Reductive cleavage of the supported adducts afforded functionalized dihydropyrans, which are of particular interest for diversity‐oriented parallel synthesis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
A Combined Theoretical and Experimental Research Project into the Aminolysis of β‐Lactam Antibiotics: The Importance of Bifunctional Catalysis
Authors: Díaz Natalia , Suárez Dimas , Sordo Tomás L. , Méndez Rosa , Villacorta Javier Martín
Published: October 2003

This paper reports the results of experimental work on the aminolysis of penicillin (6‐APA) and monobactam (aztreonam) antibiotics by propylamine or ethanolamine. In general, aztreonam is slightly more reactive than 6‐APA, despite the common assumption that the amide bond should be less activated in monobactams. Intriguingly, when ethanolamine acts as the nucleophile, the corresponding rate law has a kinetic term proportional to [RNH2][RNH3+]. To complement the experimental observations, the rate‐determining free energy barriers in aqueous solution for various mechanistic pathways were computed by standard quantum chemical methodologies. From previous theoretical work it was assumed that the aminolysis of β‐lactams proceeds through mechanisms in which either a water molecule or a second amine molecule may act as bifunctional catalysts, assisting proton transfer from the attacking amine molecule to the leaving amino group. The energy barriers as computed have moderate values (ca. 26−34 kcal·mol−1) and reproduce most of the experimentally observed kinetic trends. Furthermore, the calculations predict that positively charged ethanolamine molecules can act as bifunctional catalysts as well, thus explaining the presence of the kinetic term proportional to [RNH2][RNH3+] in the rate law. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
A Highly Efficient and Chemoselective Synthetic Protocol for Tetrahydropyranylation/Depyranylation of Alcohols and Phenols
Authors: Khan Abu T. , Mondal Ejabul , Borah Ballav M. , Ghosh Subrata
Published: October 2003

Various alcohols and phenols can be converted efficiently to the corresponding tetrahydropyranyl (THP) ethers in good yields using catalytic amounts of bromodimethylsulfonium bromide (0.005−0.02 equivalent) at room temperature. On the other hand, various THP ethers can also be deprotected to the parent alcoholic or phenolic compounds in CH2Cl2/MeOH (5:2) by employing 0.05 equivalent of the same catalyst. Some of the major advantages of this procedure are its mild conditions, that it is highly selective and efficient, high yielding, and cost‐effective, that it needs no solvent and is compatible with the presence of other protecting groups. Furthermore, no brominations occur at a double or triple bond, at an allylic position or even at an aromatic ring. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Relative Stabilities of Spirocyclopropanated Cyclopropyl Cations
Authors: Kozhushkov Sergei I. , Späth Thomas , Kosa Monica , Apeloig Yitzhak , Yufit Dmitrii S. , de Meijere Armin
Published: October 2003

Dispiro[2.0.2.1]hept‐1‐yl triflate (3), 7‐bromo‐7‐phenyldispiro[2.0.2.1]heptane (4) and 7‐chloro‐7‐phenylsulfanyldispiro[2.0.2.1]heptane (6) were prepared from bicyclopropylidene (5) in 50, 77 and 90% overall yield, respectively. 7‐Bromo‐7‐cyclopropyldispiro[2.0.2.1]heptane (8) and 7‐bromo‐7‐methyldispiro[2.0.2.1]heptane (11) were obtained by hydrobromination of 7‐cyclopropylidene‐ (7) and 7‐methylenedispiro[2.0.2.1]heptane (10) (78 and 95% yield, respectively). Methanolyses of triangulane derivatives4,6, and8as well as acetolysis of6all proceed with retention of the dispiro[2.0.2.1]heptane skeleton yielding the corresponding 7‐substituted 7‐methoxydispiro[2.0.2.1]heptanes15,21, and23as well as 7‐acetoxy‐7‐phenylsulfanyldispiro[2.0.2.1]heptane22in 90, 100, 100 and 88% yield, respectively. Methanolysis of 1‐bromo‐1‐cyclopropylcyclopropane (24) also gave mainly the ring‐retained product25(66%) along with the ring‐opened product26(33%). Apparently, an increasing number of spiro‐annelated three‐membered rings stabilizes a cyclopropyl cation against ring opening under solvolysis conditions. The rate of solvolysis, however, is only slightly affected by this spiroannelation, as the rate coefficient for the triflate3in sodium acetate‐buffered methanol was determined to bek= 3.5 × 10−4s−1at 50 °C and 1.6 × 10−4s−1at 40 °C which is virtually the same as that for cyclopropyl triflate itself (4.02 × 10−4s−1at 70 °C in acetone/H2O 3:2). No reaction was observed for the bromotriangulane11in pure methanol, and solvolysis of11in aqueous methanol only led to products27−30which were formed by ring‐enlarging and ring‐opening rearrangements of the initially formed 7‐dispiro[2.0.2.1]heptyl cation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Regioselective Friedel−Crafts Alkylation of Anilines and Amino‐Substituted Heteroarenes with Hexafluoroacetone Sesquihydrate
Authors: Masciadri Raffaello , Kamer Matthias , Nock Nadine
Published: October 2003

A variety of arenes, including anilines, pyrroles, indoles, aminooxazoles, aminothiazoles, aminoquinolines, and aminopyridines, underwent regioselective Friedel−Crafts alkylation in neat hexafluoroacetone sesquihydrate in a broad range of temperatures, reaction times, and yields (2%−94%) depending strongly on the electron density of the substrate. Prior N,N‐dibenzylation of aniline and 2‐aminopyridine strongly promoted substrate reactivity and resulted in higher yields (> 80%). The described Friedel−Crafts alkylations in hexafluoroacetone sesquihydrate occurred regioselectively at the para‐positions of anilines or at the positions β to the sp2‐hybridized nitrogen atom in heteroarenes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Cover Picture: Pd‐Assisted Multicomponent Synthesis of Heterocycles (Eur. J. Org. Chem. 21/2003)
Authors: Balme Geneviève , Bossharth Emmanuel , Monteiro Nuno
Published: October 2003

The cover picture shows the Pd‐assisted assembly of a furo[2,3‐b]pyridone through the sequential one‐pot coupling of three readily available starting materials: a 4‐alkoxy‐3‐iodo‐2‐pyridone, a terminal alkyne, and an aryl iodide. In this process a single palladium catalyst intervenes in three different transformations acting alternatively as an organometallic reagent or as a Lewis acid. Other remarkable examples illustrating the outstanding potential of Pd‐catalysed processes for the development of multicomponent syntheses of heterocyclic compounds are discussed in the Microreview by G. Balme, E. Bossharth and N. Monteiro on p. 4101 ff.
Nickel‐Based Thick Film Ethanol Sensor
Authors: Lee Yuan Gee , Chou Tse‐Chuan
Published: October 2003

Thick films ethanol sensors were prepared. The composition of the electrode was measured qualitatively to consist of Ni, O, Al, Mg and Pb. Among these composing elements, it was found that only the nickel could sense the ethanol. Both the infrared (IR) spectrum and cyclic voltammetry (CV) tests were employed to investigate its derivatives in the sensing reaction. It was found that the derivatives presented as adsorbed enol group and β‐ketoaldehyde as enols. Besides, both the redox between Ni(II) and Ni(III), and solid‐state electrochemical reactions in the electrode were found to occur in this system simultaneously. A linear dependence of response current vs. ethanol concentration with a detection limit of 37 ppm was obtained and the response time was estimated to be 140 seconds in this sensing system.
Carbonate‐Melt Oxidized Iridium Wire for pH Sensing
Authors: Wang Min , Yao Sheng
Published: October 2003

A new approach to the preparation of an iridium oxide film for pH sensing is demonstrated. A thick, uniform and dense ceramic oxide layer was grown on the surface of an iridium wire by oxidizing the wire in a molten alkali metal carbonate at high temperature. The alkali metal ion from the carbonate melt was incorporated into the oxide, resulting in a highly stable oxide compound. After treated in acid solution, the oxide layer became hydrated. SEM, XRD, TGA and element analysis were carried out to characterize the oxide film, and a possible formula of the oxide was computed as Li0.86IrO2.34(OH)0.76⋅0.39H2O. The electrode made with this new type of oxide film exhibited good pH sensitivity and stability, even in strong acid/base solutions, or in strong corrosive solution such as hydrofluoric acid. Furthermore, the electrode showed excellent long‐term stability over the test period of two and a half years. In addition, individual electrodes prepared from the same batch exhibited remarkable agreement with respect to potential/pH slopes and apparent standard electrode potentials. The performance of the electrodes depends on the properties of the oxide film, such as composition, hydration state and oxidation state.
Laccase Biosensor on Monolayer‐Modified Gold Electrode
Authors: Gupta Gautam , Rajendran Vijaykumar , Atanassov Plamen
Published: October 2003

Laccase enzymes from two different sources, namely, tree laccase from Rhus vernicifera and fungal laccase from Coriolus hirsutus were used for the development of biosensor for catechol. Laccase was immobilized onto the amine terminated thiol monolayers on gold surface by glutaraldehyde coupling. From the different thiol monolayers investigated, cystamine was found to be optimal with respect to sensitivity, stability, reproducibility, and other electrochemical properties of the enzyme electrode. Linear calibration in the range between 1 and 400 μM for catechol was obtained for fungal laccase covalently coupled on the electrode surface. The kinetic parameters determined using the Lineweaver‐Burk and Eadie‐Hofstee plots were Km=0.65 mM and Vmax=24.5 μA for fungal laccase compared to Km=5.4 mM and Vmax=6.6 μA for tree laccase on cystamine monolayer. The electrode showed good stability for 1 month without loosing appreciable activity when stored dry in a refrigerator at −20 °C.
Potentiometric Determination of Non‐Ionic Surfactants by Liquid Membrane Electrodes
Authors: Giannetto Marco , Minari Claudia , Mori Giovanni
Published: October 2003

It is well known that non‐ionic surfactants (NIS) influence remarkably the potentiometric measurements with liquid membrane ion selective electrodes (ISEs), interfering particularly on performance of ISEs for earth‐alkali metals, for which the loss of selectivity with regard to alkali metals has been documented. These studies indicate that such interferences are due to the extraction of surfactants within the membrane, where a competition takes place between the originally present ionophore and the surfactant which also acts as a ligand for alkali metals. The interpretation of such phenomena enabled one to exploit this interference for analytical purposes by membrane/solution extraction experiment monitored by UV measurements and by impedance FRA analysis on coated wire electrodes. Using Ca/Mg ISEs based on the neutral ionophore ETH 4030, it has been established that the logarithm of the Ca/Mg over Na potentiometric selectivity constant is linearly correlated with the concentration of NIS like Tegopren 5863 and Triton X‐100. The proposed method has been applied for the development of a new potentiometric analytical procedure for the determination of Tegopren 5863 in synthetic seawater (SSW), ranging from 0.25 to 5 ppm. Our procedure consists in the exposure of the electrode to stirred SSW containing the surfactant; the progressive extraction of Tegopren 5863 causes a growth in electrode's sensitivity to Na+ and K+, losing selectivity for Ca2+ and Mg2+. In turn this induces an increase of EMF, as all these ions are present in the studied matrix. The potential drift was monitored for 15 hours, showing that the process reaches thermodynamic equilibrium after about 12 hours of exposure. This method presents a value of 210 ppb of Tegopren 5863 as detection limit.
Biosensors for the Rapid Repetitive Detection of Adrenaline Using Stabilized Bilayer Lipid Membranes (BLMs) with Incorporated Calix[4]resorcinarene Receptor
Authors: Nikolelis Dimitrios P. , Petropoulou Syrago‐Styliani E. , Theoharis George
Published: October 2003

This work uses lipid film based biosensors with incorporated calix[4]resorcinarene receptor (lipophilic macrocyclic host molecule) for the rapid electrochemical detection of adrenaline. Freely‐suspended and metal supported BLMs (composed of egg phosphatidylcholine (PC) and 35% (w/w) dipalmitoyl phosphatidic acid) modified with the resorcin[4]arene receptor were used as one shot sensors to rapidly detect this catecholamine. The interactions of this compound with freely‐suspended BLMs were found to be electrochemically transduced in the form of a transient current signal with duration of seconds, which reproducibly appeared about 14 s after exposure of the membranes to adrenaline. The response time for these BLMs without incorporated receptor for adrenaline was about 1.5 min. The magnitude of the transient current signal was related to the concentration of adrenaline in bulk solution in the micromolar range. Differential scanning calorimetric (DSC) experiments were performed to explore the mechanism of interactions of BLMs with incorporated receptor with adrenaline. The interactions of adrenaline with surface‐stabilized bilayer lipid membranes (sBLMs) with incorporated receptor produced electrochemical ion current increases, which reproducibly appeared within a few seconds after exposure of the membranes to the stimulant. The use of the receptor in sBLMs increased the sensitivity of the method 6‐fold. The current signal increases were related to the concentration of adrenaline in bulk solution in the micromolar range. Stabilized lipid membranes formed by polymerization on glass fiber microfilters were used as practical chemical biosensors for the rapid detection of adrenaline. The interactions of polymerized lipid films with adrenaline were also found to provide transient current signals similar to those of freely‐suspended BLMs. The magnitude of the transient current signal was also related to the concentration of the stimulating agent in bulk solution in the micromolar range and these stabilized lipid films can be used again after storage in air. No interferences from ascorbic acid were noticed because of the negatively charged lipids in membranes. The effect of other compounds such as proteins and other compounds closely related to adrenaline was also investigated. Results of recovery experiments using human urine have shown recoveries ranged between 94 to 105%, which shows no interferences from matrix effects due to the presence of urine constituents. The present sensor based on stabilized lipid films can be used for the rapid repetitive detection of this pharmaceutical substance and keep prospects for the selective determination of catecholamines in biofluids.
Self‐Assembled Monolayer of L‐Cysteine on a Gold Electrode as a Support for Fatty Acid. Application to the Electroanalytical Determination of Unsaturated Fatty Acid
Authors: Hernández Pedro , Vicente José , Hernández Lucas
Published: October 2003

This article describes the formation of a SAM with chemisorbed cysteine to a gold surface by the thiol group to obtain a surface electrode with an amino and an acid group free for later reaction and accumulation with other molecules on the electrode surface. We explore the accumulation of unsaturated fatty acid and the electrochemical response of the electrode after modification with cysteine. The electrochemical study confirmed the accumulation of linoleic acid on the modified electrode. The optimum conditions for the determination of linoleic acid by differential pulse voltammetry of linoleic acid are studied a detection limit (3σ) of 0.03 μg mL−1 and a determination limit (10σ) of 0.10 μg mL−1 were obtained and applied to determination in olive oil and ham from Iberian breed hams.
Lead Ruthenate Pyrochlore Formed in Clay for Sensitive Determination of Dopamine
Authors: Zen Jyh‐Myng , Kumar Annamalai Senthil , Chen Huey‐Ping
Published: October 2003

Natural iron‐intercalated clay (nontronite, SWa‐1) was converted into a more efficient catalyst by formation of lead ruthenate pyrochlore (Py, Pb2Ru2−xPbxO7−y) directly inside the matrix. The new material can take advantage of the electrocatalytic properties of both Py and nontronite and can even generate new catalytic active sites due to interaction of Py and nontronite. The combination of these two interesting catalysts results in a more reactive electrode (designated as SWa‐1/PyCME) for electroanalytical applications. The preparation and characterization of the SWa‐1/PyCME as well as its electrocatalytic behavior toward the oxidation of dopamine are described in this study. Surface saturation kinetics in terms of Michaelis‐Menten kinetics suited well the oxidation of dopamine on this modified electrode. Under optimized conditions, the detection limit (S/N= 3) was 0.54 nM by square‐wave voltammetry.
Voltammetry and EQCM Investigation of Glutathione Monolayer and Its Complexation with Cu2+
Authors: Fang Cheng , Zhou Xingyao
Published: October 2003

The glutathione (GSH) self‐assembled monolayer and its compexlation with Cu2+ were studied by using voltammetry and EQCM. It was found that the monolayer could rearrange during the redox process of Cu2+/Cu+. The protonating, or not, of the carboxyl terminates of the adsorpted GSH molecules influence the compexlation interaction significantly for they are the key binding sites. The GSH monolayer had the capacity to accumulate Cu2+ and the monolayer modified gold electrode was employed to detect the low levels of Cu2+ with a limit of 1.0×10−10 mol L−1.
ECEC and ECE‐Type Mechanisms in Electrochemical Oxidation of 4‐Substituted Catechols in the Presence of 4‐Hydroxy‐6‐methyl‐2‐pyrone
Authors: Nematollahi Davood , Forooghi Zinat
Published: October 2003

Electrochemical oxidation of 3,4‐dihydroxybenzoic acid (1) and 4‐tert‐butylcatechol (5) in the presence of 4‐hydroxy‐6‐methyl‐2‐pyrone (2) as nucleophile in aqueous solution has been studied using cyclic voltammetry and controlled‐potential coulometry. The results indicate that 1 via Michael reaction under electro‐decarboxylation reaction converts to heterocyclic compound 4, and the quinone derived from 4‐tert‐butylcatechol (5) participates in Michael reaction with 2 and through an ECE mechanism converts to the corresponding o‐quinone (6a). The electrochemical synthesis of 4 and 6a has been successfully performed in an undivided cell.
Capillary electrophoresis as a simple and sensitive method to study polysaccharides of Sinorhizobium sp. NGR234
Authors: Fraysse Nicolas , Verollet Christel , Couderc François , Poinsot Véréna
Published: October 2003

We report the minimum amounts of polysaccharides (6.5 ng) that can be studied using capillary electrophoresis‐laser‐induced flurescence (CE‐LIF) and describe the separation of the various monosaccharides susceptible to occur in Sinorhizobium cell wall. On‐gel hydrolysis of the polysaccharides is described. It allowed the easy and rapid determination of the monosaccharide composition of the excised lipopolysaccharides. The composition obtained fits with gas chromatography‐mass spectrometry (GC‐MS) results. This study underlines the simplicity of using CE‐LIF, which remains an entirely “water medium” method, unlike GC‐MS which is, in addition, less sensitive (at least 100‐fold) than CE‐LIF.
Proteome database of unsensitized CD4 positive T lymphocytes in T cell receptor transgenic mice
Authors: Kaji Tomohiro , Hachimura Satoshi , Kaminogawa Shuichi
Published: October 2003

We established a two‐dimensional electrophoresis (2‐DE) mapping database of splenic CD4 T cells prepared from I‐Ad‐restricted ovalbumin (OVA)323‐339 specific T cell receptor (TCR) transgenic mice (OVA23‐3). First we examined the purification of CD4 T cells and found that the high purity of cells produced more accurate protein maps. The first dimension utilized narrow‐range immobilized pH gradients (IPGs), pH 4.0–5.0, pH 4.5–5.5, pH 5.0–6.0, and pH 5.5–6.7. Approximately 1300 spots were detected by silver staining. Detection was performed by in‐gel tryptic digestion of the spots, matrix assisted laser desorption/ionization‐time of flight‐mass spectrometry (MALDI‐TOF‐MS) technology and database searches via the world wide web (WWW). We have so far identified 255 proteins on 2‐DE gels of whole cell lysates. This is the first construction of a proteome database for murine unsensitized CD4 T lymphocytes. To examine this further, 2‐DE mapping was utilized for splenic CD4 T cells from another TCR transgenic mouse strain (DO11.10 TCR transgenic mice). Mapping patterns were found to be almost identical to those from CD4 T cells from OVA23–3 mice. These results indicated that the 2‐DE maps in this study could be used for mouse CD4 T cells to examine protein changes in cells given certain stimuli.
Proteomic analysis of the tumorigenic human prostate cell line M12 after microcell‐mediated transfer of chromosome 19 demonstrates reduction of vimentin
Authors: Liu Xuhui , Wu Yongzhong , Zehner Zendra E. , Jackson‐Cook Colleen , Ware Joy L.
Published: October 2003

Critical alterations in proteins that accompany or control the aggressiveness of human prostate cancers remain poorly defined. Previously we demonstrated that the highly tumorigenic, metastatic human prostate cell line M12 was converted to a slow growing, poorly tumorigenic cell line by introduction of an intact human chromosome 19, generating the M12 (F6) hybrid cells. The objective of this report was to identify changes in the protein profile of these M12(F6) microcell hybrid cells. A combination of two‐dimensional gel electrophoresis and matrix assisted laser desorption‐time of flight‐mass spectroscopy was used to compare proteins made by these two cell lines. No consistently increased proteins were identified. However, seven proteins were reproducibly reduced more than twofold: vimentin, hsp90, ATP synthase, 26S protease regulatory subunit, heterogeneous nuclear ribonucleoprotein, T‐Complex protein 1 β, and α‐1 tubulin. The striking reduction in vimentin protein was accompanied by significantly decreased vimentin mRNA, revealed by Northern blotting. Our findings implicate reduced vimentin in the conversion of these tumorigenic prostate epithelial cells into slow growing, less aggressive cells. These studies demonstrate that application of proteomic analysis to specific problems in an experimental context can yield biologically relevant information about the prostate cancer cell phenotype.
Towards the development of an integrated capillary electrophoresis optical biosensor
Authors: Bossi Alessandra , Castelletti Laura , Piletsky Sergey A. , Turner Anthony P. F. , Righetti Pier Giorgio
Published: October 2003

Extending the previous preliminary study on the construction of a capillary electrophoresis (CE)/sensor for the detection of reducing analytes, we focus the interest on the simultaneous detection of redox active species, which are important indicators of the oxidative damage in tissues, of food preservation, and of pollution. The CE/sensor was built by modifying the detector‐portion of the capillary with the redox‐sensitive polymer polyaniline (PANI). The analyte is detected by monitoring the changes in optical absorption of the PANI film. The CE/sensor was tested, with good results, with ascorbic acid, glutathione (GSH), as well as with compounds with very close similarity (ascorbic and isoascorbic acid). The kinetics of oxidation and reduction of PANI were evaluated. Further a PANI/CE‐biological sensor was developed by coupling an enzyme, glucose oxidase (GOD), to the PANI‐modified portion of the capillary. The stability of the immobilized GOD and the sensitivity of the CE/biosensor were studied, by using glucose as test analyte in concentrations within the physiological range. The results indicate that the CE/biosensor had good stability (more than 75% of original activity retained after 30 operational days), manufacturing reproducibility and a sensing range convenient for monitoring physiological glucose (1–24 mM).
Free solution mobility of small single‐stranded oligonucleotides with variable charge densities
Authors: Dong Qian , Stellwagen Earle , Dagle John M. , Stellwagen Nancy C.
Published: October 2003

The free solution mobilities of six single‐stranded 16‐nucleotide DNA oligomers with the same sequence, containing up to 11 neutral phosphoramidate internucleoside linkages, have been measured by capillary electrophoresis. The mobilities of the partially charged oligomers increase linearly with the logarithm of increasing charge density, as predicted by the Manning theory of electrophoresis (G. S. Manning, J. Phys. Chem. 1981, 85, 1506–1515). For comparison, the mobilities of eight fully charged single‐stranded oligomers containing similar numbers of charged phosphate residues have also been measured. The mobilities of the variable length, fully charged oligomers increase more rapidly with the increasing number of charged phosphate residues than the mobilities of the constant size, partially charged phosphoramidate derivatives, because of the larger diffusion coefficients of the modified oligomers.
Quantitative evaluation of sample application methods for semipreparative separations of basic proteins by two‐dimensional gel electrophoresis
Authors: Barry Richard C. , Alsaker Britt L. , Robison‐Cox James F. , Dratz Edward A.
Published: October 2003

The use of cup‐loading for sample application has become widely used in two‐dimensional electrophoresis (2‐DE) for resolution of basic proteins, but no side‐by‐side quantitative study has been published which compares cup‐loading with the alternative passive and active rehydration methods to fully promote one type of loading method over another. Replicate 2‐D gels from each loading method were quantitatively evaluated for gel‐to‐gel reproducibility using IPG 6–11 strips and semipreparative protein loads (300 μg). Gels were stained with SYPRO Ruby and analyzed with PDQuest. An inexpensive home‐made assembly for cup‐loading was used with the Protean IEF Cell for separation of whole cell extracts from the archaeon, Sulfolobus solfataricus. Cup‐loading was determined to be far superior for IPG 6–11 separations than active or passive rehydration methods. Cup‐loading consistently produced the greatest number of detectable spots, the best spot matching efficiency (56%), lowest spot quantity variations (28% coefficient of variation, CV), and the best‐looking gels qualitatively. The least satisfactory results were obtained with active rehydration, followed closely by passive rehydration in off‐line tubes. Passive rehydration experiments, performed using an on‐line isoelectric focusing (IEF) tray, produced comparable spot numbers to cup‐loading (84%), with 55% of the spots having higher intensity but 10% more spot quantity variance than cup‐loading.
Study of ethidium bromide effect on dsDNA separation by capillary zone electrophoresis and laser light scattering
Authors: Liang Dehai , Zhang Jun , Chu Benjamin
Published: October 2003

The effect of ethidium bromide (EB) on dsDNA separation was studied by using capillary zone electrophoresis (CZE) and laser light scattering (LLS). By increasing the concentration from 1 to 15 μg/mL, EB showed significant influence on the separation of pBR322 HaeIII in terms of resolution, speed, and signal‐over‐noise ratio. The physicochemical properties of DNA, such as mobility under electric field, charge‐over‐size ratio, and hydrodynamic radius, showed two declines, a sharp drop followed by a relaxed decrease, with increasing EB concentration. Such observations could be explained by using two modes of the dye binding process: intercalation and outside binding. The combination of results obtained from CZE and LLS also confirmed the existence of outside binding. Compared with intercalation, outside binding showed a weaker dye concentration dependence in neutralizing the negative charges on the DNA fragments. Static light scattering showed that  and  of DNA in 1×Tris‐borate‐EDTA (TBE) were increased with increasing EB concentration. / of DNA with dye had a value larger than 1.5, suggesting a random coil conformation.
Avoiding pitfalls in electrokinetic remediation: Robust design and operation criteria based on first principles for maximizing performance in a rectangular geometry
Authors: Oyanader Mario A. , Arce Pedro , Dzurik Andrew
Published: October 2003

The role of the symmetrical conditions on the temperature field is studied in a capillary of rectangular geometry. By using the generalized flux, i.e., Robin‐type of boundary conditions for the heat transfer in such a capillary domain, it is possible to identify clearly conditions under which the velocity field will depend crucially on the basic parameters and, therefore, what types of flow regimes may arise in the capillary channel. In addition, it is possible to conclude under what conditions the velocity field will not at all depend on some of these. The behavior is intimately tied to the symmetrical conditions associated with the temperature field in the system. A “skew” or asymmetrical parameter, W∞, has been identified in the temperature profiles; this parameter is useful for studying the role of the symmetrical conditions on the hydrodynamics field and in determining a set of a priori design criteria that limits the range of values of the parameters. Several numerical examples are presented to show the flow situations found in the system.
Comparison of automated in‐gel digest methods for femtomole level samples
Authors: Finehout Erin J. , Lee Kelvin H.
Published: October 2003

A comparison of automated in‐gel digestion methods for low picomolar to femtomolar levels of protein is presented. Gel spots with 4 pmol to 120 fmol of protein were stained with either Coomassie colloidal blue or SYPRO Ruby and digested using an automated platform. The sequence coverages and average peak intensities obtained from a matrix‐assisted laser desorption/ionization‐mass spectrometry (MALDI‐MS) analysis are compared. Results show that methods using an acetonitrile extraction or digest times greater than the standard 4 h give no significant increase in peptide sequence coverage for automated digestion of low protein level samples. It is also shown that digests from SYPRO Ruby‐stained gels show a greater improvement upon ZipTip cleanup than digests from Coomassie colloidal blue‐stained gels. The digests from SYPRO Ruby‐stained gels are also shown to give a higher average peptide intensity if a method with minimal gel plug washing is used.
Assessing drainage problem areas by GIS: a case study in the eastern Mediterranean region of Turkey
Authors: Cetin Mahmut , Diker Kenan
Published: October 2003

Soil productivity is affected by soil physical properties that play a crucial role in planning drainage systems. Improper planning of drainage systems can create high water table problems and, in turn, an unsuitable environment for plant growth. Therefore, drainage systems should be well planned and monitored regularly. It is very labor‐intensive and time‐consuming to determine the spatial and temporal changes in drainage parameters such as groundwater (GW) depth, elevation, hydraulic gradient and salinity by conventional methods over large areas. Geographic information systems (GIS) can be used to assess the spatial and temporal changes efficiently and rapidly. This study was conducted to determine drainage problem areas and to suggest the most suitable drainage systems for those areas by evaluating spatial and temporal changes in GW depth, elevation and salinity, with regard to drainage criteria used by the State Hydraulic Works (DSI) responsible for the development of land and water resources in Turkey. A pilot area of 8494 ha in the Lower Seyhan Plain, Adana, Turkey, was selected. The elevations and coordinates of 85 drainage observation wells were obtained from the existing maps with a scale of 1/5000 and 1/25 000, respectively. The GW depth and GW salinity data, the latter only available for July, were obtained from an archived long‐term monthly data set of the 6th Regional Directorate of the DSI. Running ArcView 3.0a, the salinity, as well as the seasonal maps of the GW depth and elevation, were developed to assess the spatial and temporal changes. Results indicated that about 99.8% of the study area was suffering from various levels of drainage problems. Main, secondary and tertiary drainage canals in the region seemed to be malfunctioning due mostly to siltation and weed problems. GW fluctuation did not seem to be of great importance, indicating a need for a subsurface drainage system. It was concluded that some areas are likely to be prone to potential GW salinization risk during the peak irrigation season if in the future, irrigation water is sparingly used and irrigation efficiency is improved. The GW hydraulic gradient did not significantly change temporally, but it did change spatially. Copyright © 2003 John Wiley & Sons, Ltd.
Food, poverty, and power in Latin America and the Caribbean
Authors: Hargreaves George H. , Merkley Gary P.
Published: October 2003

World Bank development indicators are used to show how increased production and use of electricity is strongly associated with a good quality of life for the 2.5–3 billion people around the world now living on less than US$2 a day, and for the probable future population increase in many countries. Twenty Latin American and Caribbean countries were included in this study, and their respective development indicators were compared. Some comparisons were made with world averages and with data from the same development indicators in the United States and Sweden.

An annual increase of 1000 kWh of electricity consumption per capita tends to have a very powerful influence on quality of human life by increasing average income, literacy, health, and food adequacy. Population growth and numbers of people living in poverty generally decline when electricity consumption increases, and vice versa. Some of the resources available for development, their adequacy, and the need for improved resource inventories are described. In this light, it is important to note that the potential for increased production of electricity from renewable energy in Latin America and some parts of the Caribbean is very large and should be considered by planners. The interconnection of the various electrical grids into a single grid (excluding the Caribbean) and the use of renewable energy to generate electricity are recommended. Copyright © 2003 John Wiley & Sons, Ltd.
Modeling water discharge and nitrate leaching using DRAINMOD–GIS technology at small catchment scale
Authors: El‐Sadek Alaa , Feyen Jan , Radwan Mona , El Quosy Dia
Published: October 2003

The purpose of the study was to examine the possibility of modeling nitrate leaching to surface waters using a field‐scale quasi‐two‐dimensional mechanistic flow model (DRAINMOD) in combination with a GIS. The GIS was used to describe the spatial distribution within the area of interest of soil type and land use, and to integrate the simulated nitrate leaching at field scale at the scale of the catchment. This study summarizes the method used to model the nitrate leaching at field scale and how the GIS was applied to present the spatial distribution of nitrogen loss by natural and artificial drainage. The modeling framework was applied to the Witte Nete, the Molenbeek and the Mark, three agricultural catchments in Belgium having total areas of 40.70, 57.44 and 93.62 km2, respectively to assess the vulnerability for nitrate leaching of a pilot study region in Belgium. The study illustrates that a GIS in combination with a mechanistic field scale model is a powerful and suitable tool for modeling nitrate leaching at catchment scale. The resulting vulnerability maps depict the nitrogen leaching as a function of soil type and land use and give the decision maker the opportunity to make nitrogen leaching standards site specific. Copyright © 2003 John Wiley & Sons, Ltd.
The urban market for farmers' water rights
Authors: Merrett Stephen
Published: October 2003

Allocation stress, that is, access conflicts between the agricultural, domestic, industrial, urban service and environmental uses of water, is set to become more intense in the future because of global population growth and climate change. Because of the dominant role of irrigation water use at the global level, it is imperative to explore the possibilities of reducing farmers' use of water or, at the very least, of slowing its growth. One process by which the scale of irrigation is reduced occurs when farmers choose to sell their water rights to actors that apply these released flows in towns and cities for household, manufacturing and urban service uses. In this paper a theory of price and volume determination of such markets is presented, using concepts of urban actors' maximum bid price and farmers' minimum release price for water rights. The limits of the theory are then discussed with respect to timescale, water concessions, part‐sales, sales of land, the legal context, third‐party effects, market structure and transaction costs. The main conclusion is that the market equilibrium approach is rarely applicable and that fieldwork will in general have to deal with arcane, one‐off bilateral trades. Copyright © 2003 John Wiley & Sons, Ltd.
Pricing for profitability: Give your competitors the “dog” jobs and keep the “gravy” for yourself
Authors: Daly John L.
Published: October 2003

With apologies to Woody Hayes, three things can happen when establishing prices, and two of them are bad: You
can overprice and lose a sale that would have been profitable at a lower price, or you can underprice and make
an unprofitable sale. Only the third outcome is favorable: Price appropriately and make the sale as well as a
profit. © 2003 Wiley Periodicals, Inc.
Key treasury trends for 2003
Authors: Gallanis Michael , Skerritt Susan
Published: October 2003

A new survey shows treasury managers are facing difficult challenges. The authors reveal the top six issues
that financial managers are wrestling with right now—and how they are trying to handle them. ©
2003 Wiley Periodicals, Inc.
How secure are your cash transactions?
Authors: Christensen Jo Ann , Byington J. Ralph
Published: October 2003

Of all the things dishonest employees can steal, cash is by far the most favored target. And now that money
is
tight, a new cash fraud scheme seems to hit the newspapers every day. How can you detect and prevent these
schemes? The authors have some solid answers. © 2003 Wiley Periodicals, Inc.
Analyzing sales for better cash flow management
Authors: Reider Rob , Heyler Peter B.
Published: October 2003

Do you sometimes get the feeling that your sales function is in business for itself—instead of supporting
the company? That means big problems for managing cash flow, warn the authors of this article. What steps
must you take to make sales an integral part of cash flow planning? The authors provide a detailed
how‐to guide for you to use. © 2003 Wiley Periodicals, Inc.