bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of protoberberine alkaloids in medicinal plants based on acidic potassium permanganate chemiluminescence system
Authors: Xu Xueqin , Lin Qiang , He Xiaoyan , Fu FengFu , Chen Guonan
Published: September 2009

A simple method was established to determine protoberberine alkaloids in Cortex Phellodendri and Rhizoma Coptidis based on an acidic potassium permanganate chemiluminescence (CL) system. The optimum conditions for the CL reaction between protoberberine alkaloids and potassium permanganate were studied in detail. Under the optimum conditions, the linear response ranges for berberine, palmatine and jatrorrhizine were 0.038–7.27, 0.031–18.1 and 0.012–3.61 μg/mL with detection limits of 0.005, 0.004 and 0.0007 μg/mL, respectively. This method was successfully applied to determine the content of protoberberine alkaloids (calculated using berberine as an index) in Cortex Phellodendri and Rhizoma Coptidis. In addition, a possible mechanism of this CL reaction was proposed on the basis of the investigation of CL, UV and fluorescent spectra of protoberberine alkaloids in acidic solution containing potassium permanganate. Copyright © 2009 John Wiley & Sons, Ltd.
Resonance Rayleigh‐scattering spectral method for the determination of some aminoglycoside antibiotics using CdTe quantum dots as a probe
Authors: Wang Lei , Peng Juanjuan , Liu Zhengwen , He Youqiu
Published: September 2009

A novel method is used for the determination of some aminoglycoside antibiotics (AGs) such as etimicin (ETM), isepamicin (ISP) and amikacin (AMK). It is based on the resonance Rayleigh scattering (RRS) intensities enhanced by AGs‐induced CdTe quantum dots aggregation. Under the optimum conditions, the increments in RRS intensity were directly proportional to the concentration of AGs in certain ranges. At the same time, the second‐order scattering, the frequency‐doubling scattering and the frequency‐trebling scattering intensities were also enhanced and their increments were proportional to the concentration of AGs. Among them, the RRS method had the highest sensitivity; the linear ranges and detection limits for ETM, ISP and AMK were 0.085–7.2, 0.0067–1.2, 0.017–6.0 and 0.025, 0.0051, 0.0020 μg mL−1. This method was applied to the measurement of AGs in human serum and urine with satisfactory results. In addition, the reaction mechanism and the reasons for the enhancement of RRS are discussed using fluorescence, RRS, transmission electron microscope technology and quantum chemistry method. Copyright © 2009 John Wiley & Sons, Ltd.
Medical and psychiatric problems among men and women in a community corrections residential setting
Authors: Gunter Tracy D. , Philibert Robert , Hollenbeck Nancy
Published: September 2009

Though the medical and mental health morbidity of incarcerated offenders has been discussed in a number of recent reports, very few data have been published concerning medical and mental health problems facing those on community corrections supervision. In this study of community corrections offenders utilizing residential facilities, we found that frequencies of substance use disorders, other mental health disorders, and medical problems exceeded frequencies found in the community and, in some cases, were higher than frequencies found in incarcerated individuals. Of particular concern were the high frequencies of substance use disorders, traumatic brain injury, anxiety states, suicidal ideation, and prior self‐harm. While the level of self‐reported medical and mental health service utilization was higher than expected, it appeared low relative to the disease burden reported by this special population. We conclude that concurrent evaluation and treatment of medical and psychiatric problems during the process of community supervision is indicated in this population. Copyright © 2009 John Wiley & Sons, Ltd.
Malingering in a correctional setting: the use of the Structured Interview of Reported Symptoms in a jail sample
Authors: McDermott Barbara E. , Sokolov Gregory
Published: September 2009

The ability to detect malingering in the correctional setting is of paramount importance. The burgeoning jail and prison population combined with statutory requirements for the provision of mental health treatment require that only those most in need receive these services. Several structured assessments have been developed to assist in the identification of individuals more likely to be feigning psychiatric symptoms. Prior to the development of these specialized assessments, subscales of standard psychological tests were used as an indicator of assessment attitudes, for both malingering and other dissimulation. At the Sacramento County (CA) Jail, the Structured Interview of Reported Symptoms (SIRS) is routinely administered when clinicians feel there is a possibility that an inmate receiving psychiatric services may be feigning or exaggerating his/her symptoms. Our study examined data from these evaluations of inmates in conjunction with other clinical data (e.g., psychiatric diagnosis, educational level) to determine those factors most associated with malingering in jail inmates. Our results indicate that the prevalence of malingering in our sample was quite high: over 66% were found to be malingering based on the scoring criteria for the SIRS. Inmates diagnosed with Antisocial Personality Disorder were no more likely to feign symptoms than inmates without this diagnosis. Inmates designated as malingering in their charts were no more likely to be found malingering on the SIRS, suggesting that they may have adopted an effective strategy. Copyright © 2009 John Wiley & Sons, Ltd.
Structure‐Specific Recognition of Friedreich's Ataxia (GAA)n Repeats by Benzoquinoquinoxaline Derivatives
Authors: Bergquist Helen , Nikravesh Abbas , Fernández Raquel Domingo , Larsson Veronica , Nguyen Chi‐Hung , Good Liam , Zain Rula
Published: September 2009

Expansion of GAA triplet repeats in intron 1 of the FXN gene reduces frataxin expression and causes Friedreich's ataxia. (GAA)n repeats form non‐B‐DNA structures, including triple helix H‐DNA and higher‐order structures (sticky DNA). In the proposed mechanisms of frataxin gene silencing, central unanswered questions involve the characterization of non‐B‐DNA structure(s) that are strongly suggested to play a role in frataxin expression. Here we examined (GAA)n binding by triplex‐stabilizing benzoquinoquinoxaline (BQQ) and the corresponding triplex‐DNA‐cleaving BQQ‐1,10‐phenanthroline (BQQ‐OP) compounds. We also examined the ability of these compounds to act as structural probes for H‐DNA formation within higher‐order structures at pathological frataxin sequences in plasmids. DNA‐complex‐formation analyses with a gel‐mobility‐shift assay and sequence‐specific probing of H‐DNA‐forming (GAA)n sequences by single‐strand oligonucleotides and triplex‐directed cleavage demonstrated that a parallel pyrimidine (rather than purine) triplex is the more stable motif formed at (GAA)n repeats under physiologically relevant conditions.
Selective Catalytic Hydrogenation of Functionalized Nitroarenes: An Update
Authors: Blaser Hans‐Ulrich , Steiner Heinz , Studer Martin
Published: September 2009

In this update, progress made in the last decade for the selective catalytic hydrogenation of nitroarenes in the presence of other reducible functions is reviewed. The main focus is on catalytic systems capable of reducing nitro groups with very high chemoselectivity in substrates containing carbon–carbon or carbon–nitrogen double or triple bonds, carbonyl or benzyl groups, and multiple Cl, Br, or I substituents. The performance of new catalyst types is described, most notably of gold‐based catalysts, but also of modified classical Pt, Pd, and Ni catalysts, as well as homogeneous catalysts. The best results for the various chemoselectivity problems are compiled and assessed with regard to their versatility and synthetic viability. In addition, progress in understanding mechanistic aspects are briefly described.
Highly Enhanced Phenol Hydroxylation in [h0h]‐Oriented Fe–ZSM‐5 Membranes
Authors: Lang Lin , Liu Xiufeng , Hu Mingliang , Zhang Baoquan
Published: September 2009

Catechol (CAT) and hydroquinone (HQ) are two important diphenol isomers with a variety of industrial applications. The hydroxylation of phenol catalyzed by transition metal (TM) substituted ZSM‐5 is an environmentally benign route for diphenol production, which is usually governed by intracrystalline diffusion. Therefore, the availability of highly oriented TM‐ZSM‐5 membranes and their utilization in an interphase membrane reactor can significantly promote the hydroxylation of phenol. The continuous and [h0h]‐oriented Fe–ZSM‐5 membrane on the porous α‐Al2O3 was prepared using a new seeded growth method. Characterization was carried out by using SEM, XRD, UV/Vis, and EPMA techniques, which demonstrated that the [h0h]‐oriented membrane consists of Fe substituted ZSM‐5 crystal grains with an Si/Fe ratio of approximately 75. Compared with the catalytic performance of different sized Fe–ZSM‐5 grains loaded in the traditional slurry reactor, the [h0h]‐oriented Fe–ZSM‐5 membrane in the interphase membrane reactor showed significantly improved phenol conversion and selectivity for CAT and HQ due to the molecular path control in the zeolite membranes.
A Mechanism of Adsorption of β‐Nicotinamide Adenine Dinucleotide on Graphene Sheets: Experiment and Theory
Authors: Pumera Martin , Scipioni Roberto , Iwai Hideo , Ohno Takahisa , Miyahara Yuji , Boero Mauro
Published: September 2009

β‐Nicotinamide adenine dinucleotide (NAD+) and its reduced form (NADH) play major roles in the development of electrochemical enzyme biosensors and biofuel cells. Unfortunately, the oxidation of NADH at carbon electrodes suffers from passivation of the electrodes and a decrease in passing currents. Here, we investigate experimentally and theoretically the reasons for such passivation. High‐resolution X‐ray photoelectron spectroscopy (HR‐XPS), voltammetry, and amperometry show that adsorption occurs on the edges and “edge‐like” defects of graphene sheets. HR‐XPS and ab initio molecular dynamics show that the adsorption of NAD+ molecules on the edges of graphene happens due to interaction with oxygen‐containing groups such as carboxylic groups, while graphene edges substituted only with hydrogen are prone to passivation.
Oxidative Interception of the Hydroamination Pathway: A Gold‐Catalyzed Diamination of Alkenes
Authors: Iglesias Alvaro , Muñiz Kilian
Published: September 2009

A complimentary diamination of alkenes by using homogeneous gold catalysts is described. The reaction is one of very few examples of homogeneous gold oxidation catalysis and proceeds with high selectivity under mild conditions. Individual steps of the suggested catalytic cycle were investigated on isolated model gold complexes, and new pathways for gold‐catalyzed amination reactions were established. The key step is an intramolecular alkyl–nitrogen bond formation from a gold(III) intermediate. This process validates the concept of reductive elimination from high oxidation catalyst states for this type of CN bond forming reactions.
High‐Affinity Inhibitors of tRNA‐Guanine Transglycosylase Replacing the Function of a Structural Water Cluster
Authors: Kohler Philipp C. , Ritschel Tina , Schweizer W. Bernd , Klebe Gerhard , Diederich François
Published: September 2009

The tRNA‐modifying enzyme tRNA–guanine transglycosylase (TGT) is essential for the pathogenic mechanism of Shigella flexneri, the causing agent of the bacterial diarrheal disease shigellosis. Herein, the synthesis of a new class of rationally designed 6‐amino‐imidazo[4,5‐g]quinazolin‐8(7H)‐one‐ (lin‐benzoguanine) based inhibitors of TGT are reported. In order to accommodate a small hydrophobic crevice opening near the binding site of ribose‐34, 2‐aminoethyl substituents were introduced in position 4 of the heterocyclic scaffold. For this purpose, a synthetic sequence consisting of iodination, Suzuki cross‐coupling, hydroboration, Mitsunobu reaction, and Gabriel synthesis was employed, furnishing a primary amine that served as a common intermediate for the preparation of a series of derivatives. The resulting ligands displayed very low inhibition constants, down to Ki=2 nM. Substantial additional inhibitory potency is gained by interaction of terminal lipophilic groups attached to the substituent at position 4 with the hydrophobic crevice shaped by Val45 and Leu68. At the same time, the secondary ammonium center in the substituent displaces a cluster of water molecules, solvating the catalytic residues Asp102 and Asp280, without loss in binding affinity. In addition, a synthetic intermediate with an unusual 3,6,7,8,9,10‐hexahydroimidazo[4,5‐g][1,3]benzodiazepine core, as confirmed by X‐ray analysis, is reported.
Vinylation of Nitro‐Substituted Indoles, Quinolinones, and Anilides with Grignard Reagents
Authors: Egris Riccardo , Villacampa Mercedes , Menéndez J. Carlos
Published: September 2009

The reaction of vinyl Grignard reagents with o‐methoxynitroarenes containing an electron‐releasing substituent para to the nitro group proceeds through a pathway that is different from the initially expected Bartoli indole synthesis. Thus, instead of giving fused indole derivatives, these reactions provide a very mild and efficient new procedure for the synthesis of synthetically relevant aromatic systems containing an o‐nitrovinyl moiety, such as 5‐nitro‐4‐vinylindoles, 6‐nitro‐7‐vinylindoles, 6‐nitro‐5‐vinyl‐2(1H)quinolinones, and 4‐nitro‐3‐vinylanilines.
Azoles as Reactive Nucleophiles with Cyclic Perfluoroalkenes
Authors: Garg Sonali , Twamley Brendan , Zeng Zhuo , Shreeve Jean'ne M.
Published: September 2009

Di‐ and multiazole‐substituted fluorocyclic products (2–13) were readily synthesized in good to high yields. These were synthesized by nucleophilic substitution reactions of perfluorocycloalkenes with azoles (i.e., imidazole, triazole) involving simple reaction procedures. Interestingly, these azoles were later found to be reactive not only with the vinylic, but also with the allylic fluorine atoms. This resulted in the substitution of up to six azoles on the fluorinated rings. Stoichiometry plays a key role in determining the degree of substitution. For comparison, the analogous reactions of N‐substituted 1‐(trimethylsilyl)‐imidazole and 1‐(trimethylsilyl)‐1,2,4‐triazole were also investigated. All of the new compounds were fully characterized by elemental, spectral (19F, 1H, 13C NMR), and thermal differential scanning calorimetry (DSC) analyses.
Studies on the Synthesis and Activity of Three Tripalladium Complexes Containing Planaramine Ligands
Authors: Farhad Mohammad , Yu Jun Qing , Beale Philip , Fisher Keith , Huq Fazlul
Published: September 2009

The present study deals with the synthesis, characterization and activity against human cancer cell lines: A2780, A2780cisR and A2780ZD0473R of three tripalladium complexes, MH3, MH4 and MH5, that each have two planaramine ligands bound to the central metal ion. Cellular uptake levels, extent of DNA binding, and nature of interaction with salmon sperm and pBR322 plasmid DNA were determined for each complex. Palladium compounds are much more reactive than their corresponding platinum derivatives, which makes them therapeutically inactive but toxic. However, the results of the present study suggest that significant antitumour activity can be introduced in palladium complexes by lessening their reactivity by the introduction of sterically hindered ligands such as 2‐hydroxypyridine, 3‐hydroxypyridine and 4‐hydroxypyridine. When bound to the central palladium ion, 4‐hydroxypyridine appears to be more activating than 2‐hydroxypyridine and 3‐hydroxypyridine, suggesting that noncovalent interactions, such as hydrogen bonding, may also be key determinants of antitumour activity in addition to the steric effect. While cisplatin binds with DNA to form intrastrand GG adducts that causes local bending of a DNA strand, these planaramine‐derived palladium complexes are expected to bind with DNA and form a number of long‐range interstrand GG adducts that would cause a global change in DNA conformation, provided the tripalladium cations in MH3, MH4 and MH5 persist under physiological conditions.
Ionic Association of the Ionic Liquids [C4mim][BF4], [C4mim][PF6], and [Cnmim]Br in Molecular Solvents
Authors: Wang Huiyong , Wang Jianji , Zhang Sheli , Pei Yuanchao , Zhuo Kelei
Published: September 2009

Considering the ionic nature of ionic liquids (ILs), ionic association is expected to be essential in solutions of ILs and to have an important influence on their applications. Although numerous studies have been reported for the ionic association behavior of ILs in solution, quantitative results are quite scarce. Herein, the conductivities of the ILs [Cnmim]Br (n=4, 6, 8, 10, 12), [C4mim][BF4], and [C4mim][PF6] in various molecular solvents (water, methanol, 1‐propanol, 1‐pentanol, acetonitrile, and acetone) are determined at 298.15 K as a function of IL concentration. The conductance data are analyzed by the Lee–Wheaton conductivity equation in terms of the ionic association constant (KA) and the limiting molar conductance (Λm0). Combined with the values for the Br− anion reported in the literature, the limiting molar conductivities and the transference numbers of the cations and [BF4]− and [PF6]− anions are calculated in the molecular solvents. It is shown that the alkyl chain length of the cations and type of anion affect the ionic association constants and limiting molar conductivities of the ILs. For a given anion (Br−), the Λm0 values decrease with increasing alkyl chain length of the cations in all the molecular solvents, whereas the KA values of the ILs decrease in organic solvents but increase in water as the alkyl chain length of the cations increases. For the [C4mim]+ cation, the limiting molar conductivities of the ILs decrease in the order Br−>[BF4]−>[PF6]−, and their ionic association constants follow the order [BF4]−>[PF6]−>Br− in water, acetone, and acetonitrile. Furthermore, and similar to the classical electrolytes, a linear relationship is observed between ln KA of the ILs and the reciprocal of the dielectric constants of the molecular solvents. The ILs are solvated to a different extent by the molecular solvents, and ionic association is affected significantly by ionic solvation. This information is expected to be useful for the modulation of the IL conductance by the alkyl chain length of the cations, type of anion, and physical properties of the molecular solvents.
Use of flow cytometry as a quality control device for liquid‐based cervical cytology specimens
Authors: Kottaridi Christine , Georgoulakis John , Kassanos Dimitrios , Pappas Asimakis , Spathis Aris , Margari Niki , Aninos Dionissios , Karakitsos Petros
Published: September 2009

Background:

Cervical cancer is the second most common cancer in women worldwide comprising a major concern of public health. Liquid‐based cytology provides significantly more effective detection of low‐grade intraepithelial neoplasia or more severe lesions, without loss of diagnostic specificity and reduces the number of cases classified as unsatisfactory. The objective of the study is the evaluation of flow cytometry as a rapid tool for quality control of the liquid specimen adequacy for the purpose of precise cytological diagnosis in detecting cervical abnormalities.

Methods:

A total of 1,854 women undergoing routine cervical cytology joined this cohort study. A monolayer smear was prepared and 1 ml aliquot was removed and prepared for flow cytometric analysis. Cells were fixed and run on a Partec CyFlow SL, with front scatter (FSS) and side scatter (SSC) set on logarithmic scale. The forward scatter versus side scatter dot‐plot was used for the distinction of ectocervical, endocervical, and polymorphonuclear cells.

Results:

In the total of 1,854 cases, 15 specimens (0.8%) were characterized by the cytopathologist as unsatisfactory. Inadequacy was confirmed by flow cytometric analysis for four samples. Monolayer smears were reprepared for the remaining 11 samples. After the second microscopic observation, six out of the 11 cases (54.5%) were found to be satisfactory, whereas the remaining five were still designated as unsatisfactory by the cytopathologist.

Conclusion:

The parallel screening of adequacy by quantification of cell populations with flow cytometry can serve as an internal control for diagnosis and can overall decrease the number of unsatisfactory samples. © 2009 Clinical Cytometry Society
Chains of Alkaline Metal Cations and Tetracyanidoborato Anions – Syntheses, Structures and Properties of the New [AI(18‐crown‐6)][B(CN)4)] (AI = Cs, Rb)
Authors: Bernsdorf Arne , Köckerling Martin
Published: September 2009

[Cs(18‐crown‐6)][B(CN)4] and [Rb(18‐crown‐6)][B(CN)4] can be obtained as colourless transparent crystals by slow evaporation of the solvent of aqueous solutions of these compounds. Both substances crystallise in the monoclinic crystal system; [Cs(18‐crown‐6)][B(CN)4]: C2/c, a = 13.819(1), b = 15.841(1), c = 10.1717(7) Å, β = 92.117(4)°, V = 2225.0(3) Å3, Z = 4; [Rb(18‐crown‐6)][B(CN)4]: P21/n, a = 14.237(2), b = 9.455(1), c = 15.942(2) Å, β = 94.319(4)°, V = 2139.9(5) Å3, Z = 4. These compounds are characterised by unprecedented linear coordination chains. Double rows of alkaline metal cations, encapsulated in 18‐crown‐6 ether molecules, which are oriented approximately face‐to‐face, are interconnected by tetracyanidoborato anions. Nevertheless, the connectivity differs significantly between the two compounds. In the Cs compound the [B(CN)4]− anions are tetrafunctional with two CN groups coordinating in a chelate‐type mode to one Cs cation, whereas the other two CN groups bridge two neighbouring Cs cations of the opposite row of [Cs(18‐crown‐6)]+ units. In the Rb compound only two of the four CN groups are bonded to the cations, the other two are uncoordinated. The bonded CN groups bridge between two Rb cations of opposite rows. These two compounds show that the[B(CN)4]− anion has a tremendous variability of coordination modes. Not only can 3D network structures be formed by using [B(CN)4]− anionic units but also low‐dimensional structures, as shown by these two new compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
NHTS: A Hollow, Noble‐Metal‐Modified Titanium Silicalite
Authors: Shi Chunfeng , Zhu Bin , Lin Min , Long Jun
Published: September 2009

The major drawback of direct oxidation technology (onsite hydrogen peroxide production followed by its conversion into organic oxides without refining) is the design and preparation of the bifunctional catalysts used therein. Herein we present a bifunctional catalytic material (NHTS), which is synthesized by a revised semi‐in‐situ method that allows a noble metal to be distributed throughout the titanosilicate framework and also results in a redistribution of active Ti species throughout the crystals, thereby enriching the surface of the hollow crystals with catalytic species. This compound has been characterized by various techniques and its activity and selectivity for the direct epoxidation of propylene investigated. The results indicate that NHTS shows a very ordered MFI topology, with the noble metal incorporated in the framework, and a hollow structure, which makes it a good alternative for catalytic oxidations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis and Catalytic Properties in Olefin Epoxidation of Octahedral Dichloridodioxidomolybdenum(VI) Complexes Bearing N,N‐Dialkylamide Ligands: Crystal Structure of [Mo2O4(μ2‐O)Cl2(dmf)4]
Authors: Gago Sandra , Neves Patrícia , Monteiro Bernardo , Pessêgo Márcia , Lopes André D. , Valente Anabela A. , Almeida Paz Filipe A. , Pillinger Martyn , Moreira José , Silva Carlos M. , Gonçalves Isabel S.
Published: September 2009

The catalytic performance of the complexes [MoO2Cl2(L)2] [L = N,N‐dimethylformamide (dmf), N,N‐dimethylacetamide (dma), N,N‐dimethylpropionamide (dmpa), N,N‐diethylformamide (def) and N,N‐diphenylformamide (dpf)] was examined in the epoxidation of cis‐cyclooctene with tert‐butyl hydroperoxide (tbhp) at 55 °C and in the absence of a cosolvent. The complexes showed high turnover frequencies in the range of 561–577 mol molMo–1 h–1, giving the epoxide as the only product in ≥98 % yield after 6 h. The reaction rates decreased significantly in consecutive runs carried out by recharging the reactors with olefin and oxidant. On the basis of the IR spectroscopic characterisation of the solids recovered at the end of the catalytic reactions, the decrease in activity is attributed to the formation of dioxido(μ‐oxido)molybdenum(VI) dimers. Accordingly, the treatment of [MoO2Cl2(dmf)2] with an excess amount of tbhp led to the isolation of [Mo2O4(μ2‐O)Cl2(dmf)4], which was characterised by single‐crystal X‐ray diffraction and found to exhibit a catalytic performance very similar to that found in the second runs for the mononuclear complexes. The kinetics of the reaction of [MoO2Cl2(dmf)2] with tbhp was further examined by UV/Vis spectroscopy, allowing rate constants and activation parameters to be determined. For the dpf adduct, the effect of different solvents on cyclooctene epoxidation and the epoxidation of other olefins, namely, (R)‐(+)‐limonene, α‐pinene and norbornene, were investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Design, Self‐Assembly, and Molecular Structures of 3D Copper(II) Capsules Templated by BF4– Guest Anions
Authors: Desmarets Christophe , Policar Clotilde , Chamoreau Lise‐Marie , Amouri Hani
Published: September 2009

The synthesis of two 3D M2L4 copper(II) capsules, {[BF4⊂(CH3CN)2Cu2(L1)4][BF4]3} (1) and {[BF4⊂(BF4)2Cu2(L1)4][BF4]} (2), by using 1,3‐(benzimidazol‐1‐ylmethyl)‐2,5‐dimethoxy‐4,6‐dimethylbenzene (L1) as a semirigid exobidentate ligand and [Cu(CH3CN)4][BF4]2 as a metallobrick is reported. Single‐crystal X‐ray diffraction studies show the encapsulation of a BF4– anion in 1 and 2. Moreover, 2 displayed three coordinated BF4– anions, which is rare in supramolecular coordination host–guest chemistry. Remarkably, in both metallocages the weakly coordinated BF4– anion acts as a template and interacts with the metal center through a weak Cu···F contact. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Unique Catalytic Performance of the Polyoxometalate [Ti2(OH)2As2W19O67(H2O)]8–: The Role of 5‐Coordinated Titanium in H2O2 Activation
Authors: Kholdeeva Oxana A. , Donoeva Baira G. , Trubitsina Tatiana A. , Al‐Kadamany Ghada , Kortz Ulrich
Published: September 2009

Tetra‐n‐butylammonium (TBA) salts of the dititanium sandwich‐type 19‐tungstodiarsenate(III) [Ti2(OH)2As2W19O67(H2O)]8– (1) revealed a unique catalytic performance in the selective oxidation of organic compounds with aqueous hydrogen peroxide. The selectivity of alkene oxidation strongly depends on the amount of acidic protons in the cationic part of 1, which can be controlled by pH of precipitation of the TBA salt. Selectivities of almost 100 % were achieved for cyclohexene epoxidation by using TBA5.5Na1.5K0.5H0.5‐1. In the presence of TBA5.5K0.5H2‐1, cyclohexene epoxide readily transformed into trans‐1,2‐cyclohexanediol, 2‐hydroxycyclohexanone, and C–C bond‐cleavage products. No allylic oxidation products were found. Vicinal diols yielded α‐hydroxyketones and (di)carboxylic acids. Ketonization of cyclohexanol proceeded with selectivity as high as 98 %, whereas 1‐hexanol produced hexanal and hexanoic acid. The oxidation products are consistent with a heterolytic mechanism of H2O2 activation. The stability of 1 under turnover conditions was confirmed by IR spectroscopy. The presence of titanium atoms in the belt of 1 is vital for the catalytic performance. The titanium‐free analogue, [As2W21O67(H2O)]6– (2), revealed lower activity and selectivity in the oxidation of alcohols and was not active in the oxidation of alkenes. The catalytic performance of 1 contrasts that of polyoxometalates containing hexacoordinate Ti atoms, for example, TBA7[(PTiW11O39)2OH], TBA8H7[{Ti3PW9O37(OH)}3(PO4)], and TBA17[(α‐Ti3SiW9O37OH)3{TiO3(OH2)3}], for which a homolytic oxidation mechanism was manifested by the formation of cyclohexene allylic oxidation products. The unique ability of 1 to catalyze heterolytic oxidations with the use of hydrogen peroxide most likely originates from the specific coordination number (5) and geometry (square‐pyramidal) of the Ti atoms in this polyanion.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
BiVO4 Hollow Nanospheres: Anchoring Synthesis, Growth Mechanism, and Their Application in Photocatalysis
Authors: Yin Wenzong , Wang Wenzhong , Shang Meng , Zhou Lin , Sun Songmei , Wang Lu
Published: September 2009

An anchoring method was developed to synthesize monoclinic BiVO4 (m‐BiVO4) hollow spheres with a size of about 700 nm by employing colloidal carbon spheres (CCSs) as hard templates. The influence of synthesis conditions and the growth mechanism were investigated with XRD, TEM, and SEM through a series of comparison experiments. It was found that two‐stage heat treatment was essential for the synthesis of BiVO4 hollow nanospheres. The Bi3+ ions were firstly adsorbed on the surface of the CCSs and worked as anchors in the first stage (80 °C). In the second stage (100 °C), the VO3– ions reacted with the anchored Bi3+ ions, and amorphous BiVO4 nanoparticles were thus precipitated on the CCSs surface. The analysis on the calcination process revealed that calcination promoted the crystallization of amorphous BiVO4 into m‐BiVO4 crystals at 236 °C and removed the CCSs at 353 °C. The as‐prepared BiVO4 hollow nanospheres exhibited higher photocatalytic activity than BiVO4 prepared by the aqueous method and by a solid‐state reaction in the degradation of rhodamine B and acetaldehyde, which could be attributed to their higher BET surface area (5.85 m2 g–1) and larger band gap (2.36 eV). Given the general adsorption of metal ions on the CCSs surface, this anchoring method could be extended to synthesize other hollow‐structured multicomponent oxides. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Homo‐ and Copolymerization of Aromatic Diynes by Ruthenium/Acid‐Promoted (RAP) Catalysis
Authors: Pasquini Chiara , Fratoddi Ilaria , Bassetti Mauro
Published: September 2009

9,9‐Bis(2′‐ethylhexyl)‐2,7‐diethynylfluorene (1) or 1‐(2′‐ethylhexyloxy)‐2,5‐diethynyl‐4‐methoxybenzene (2) react in the presence of the [{RuCl(μ‐Cl)(p‐cymene)}]2/AcOH catalytic system to yield the corresponding poly(aryleneethynylenevinylene) π‐conjugated homopolymers, featuring the areneenyne repeat unit (Ar–C≡C–CH=CH–) and characterized by high regio‐ and stereoselectivity [(E) > 93 %]. The copolymerization of 1 and 2 affords poly‐(E)‐FL‐ethynylenevinylene‐co‐(E)‐MEH‐ethynylenevinylene [FL = fluorene; MEH = 1‐(2′‐ethylhexyloxy)‐4‐methoxybenzene], as the first example of a random copolymer derived from the polyaddition process of aromatic diynes. The catalytic system of this atom‐economic polyaddition process is formed in situ from the commercially available ruthenium dimer and acetic acid and promotes the C–C coupling at room temperature. The branched 2‐ethylhexyl chains in the arene moiety assist the formation of polymers with degrees of polymerization in the range of 9–20 repeat units. The optical properties of the new polymers were studied in chloroform solution and in film and compared to those of the main classes poly(arylenevinylene) and poly(aryleneethynylene) conjugated polymers.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis of the First Selenium‐Containing Acyclic Nucleosides and Anomeric Spironucleosides from Carbohydrate Precursors
Authors: Maza Susana , López Óscar , Martos Sergio , Maya Inés , Fernández‐Bolaños José G.
Published: September 2009

We report the synthesis of acyclic and spiranic imidazole‐derived C‐selenonucleosides. 5‐Hydroxy‐4‐tetrahydroxybutyl imidazolidine‐2‐selones, a novel class of acyclic selenonucleosides, were transformed into (tetrahydroxybutylimidazol‐2‐yl)diselenide, by acetylation and chemoselective N‐deacetylation with methanolic imidazole. Furthermore, the synthesis of a new class of conformationally restricted arabino‐configured spironucleosides containing an imidazolidine‐2‐selone unit around the glycosidic bond was achieved, starting from N‐fructosamines, via 4‐hydroxy‐4‐tetrahydoxybutyl‐imidazolidine‐2‐selones as the key intermediates. Acetylation–deacetylation of these intermediates gave access to stable aromatic imidazoline‐2‐selones.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Organocatalytic Enantioselective Michael Addition of 4‐Hydroxycoumarin to α,β‐Unsaturated Ketones: A Simple Synthesis of Warfarin
Authors: Dong Zhenhua , Wang Lijia , Chen Xiaohong , Liu Xiaohua , Lin Lili , Feng Xiaoming
Published: September 2009

A type of C2‐symmetric secondary amine amide catalysts were developed for the asymmetric Michael addition of 4‐hydroxycoumarin to α,β‐unsaturated ketones. A series of important biologically and pharmaceutically active compounds were obtained in excellent yields (up to 99 %) with high enantioselectivities (up to 89 % ee) under mild conditions. In addition, enantiopure product could be obtained by a single recrystallization. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis, Structure and Electrical Properties of Mo‐doped CeO2–Materials for SOFCs
Authors: Li Q. , Thangadurai V.
Published: September 2009

In this paper, we report the synthesis, structure and electrical conductivity of Mo‐doped compounds with a nominal chemical formula of Ce1–xMoxO2+δ (x = 0.05, 0.07, 0.1) (CMO). The formation of fluorite‐like structure with a small amount of Ce8Mo12O49 impurity (JCPDS Card No. 31‐0330) was confirmed using a powder X‐ray diffraction (PXRD). The fluoride‐type structure was retained under wet H2 and CH4 atmospheres at 700 and 800 °C, while diffraction peaks due to metal Mo were observed in dry H2 under the same condition. AC impedance measurements showed that the total conductivity increases with increasing Mo content in CMO, and among the investigated samples, Ce0.9Mo0.1O2+δ exhibited the highest electrical conductivity with a value of 2.8 × 10–4 and 5.08 × 10–2 S cm–1 at 550 °C in air and wet H2, respectively. The electrical conductivity was found to be nearly the same, especially at high temperatures, in air, O2 and N2. Chemical compatibility of Ce0.9Mo0.1O2+δ with 10 mol‐% Y2O3 stabilised ZrO2 (YSZ) and Ce0.9Gd0.1O1.95 (CGO) oxide ion electrolytes in wet H2 was evaluated at 800–1,000 °C, using PXRD and EDX analyses. PXRD showed that CMO was found to react with YSZ electrolyte at 1,000 °C. The area specific polarisation resistance (ASPR) of Ce0.9Mo0.1O2+δ on YSZ was found to be 8.58 ohm cm2 at 800 °C in wet H2.
Zurich's New Apportionment
Authors: Pukelsheim Friedrich
Published: September 2009

How mathematics has played an essential role in giving an ancient democracy a new electoral system
The Diary of a Jack of All Trades
Authors: Unterstell Rembert
Published: September 2009

The German Empire, Republic, and dictatorship: Harry Graf Kessler was a chronicler of his era. At the German Literature Archive in Marbach his chronicle of the century is being edited meticulously – giving us a fascinating glimpse of “old Europe” page by page
Lakes in the Sahara
Authors: Kröpelin Stefan
Published: September 2009

Large bodies of water in the middle of the desert are not only a natural spectacle, they also contain extremely precise environmental archives. Sediments extracted from these lakes document climate evolution and provide information on dust storms, savannah fires and volcanic eruptions. A journey to north‐east Chad
Two Novel Antioxidative Stilbene Tetramers from Parthenocissus laetevirens
Authors: He Shan , Jiang Liyan , Wu Bin , Zhou Jing , Pan Yuan‐Jiang
Published: September 2009

Laetevirenols F (1) and G (2), two novel stilbene tetramers with an unprecedented skeleton, were isolated from Parthenocissus laetevirens. Their structures were elucidated by spectroscopic analysis, including 1D‐ and 2D‐NMR experiments, and their possible biogenetic pathway was discussed. In addition, both compounds were determined to be potent singlet‐oxygen quenchers by electron paramagnetic resonance (EPR) experiments, which highlights their potential pharmacological applications in singlet oxygen mediated diseases.
Three New Daphne Diterpenes from the Buds of Daphne genkwaSieb. etZucc. Processed by Rice Vinegar
Authors: Zeng Yi‐Mei , Zuo Wen‐Jian , Sun Min‐Ge , Meng He , Wang Qing‐Hui , Wang Jin‐Hui , Li Xian
Published: September 2009

Three new Daphne diterpenes, yuanhuaoate A (1), yuanhuaoate B (2), and yuanhuaoate C (3), were isolated from the buds of Daphne genkwa Sieb. et Zucc. processed by rice vinegar. Their structures and relative configurations were established by analysis of spectroscopic data. Their absolute configurations were assigned by the CD technique, applied for the first time to Daphne diterpenes.
Seven New Phenolic Glucosides from Viburnum cylindricum
Authors: Tu Lin , Xu Gang , Zhao Yu , Peng Li‐Yan , He Juan , Guo Na , Zhao Qin‐Shi
Published: September 2009

Seven new phenolic glucosides, 2′‐O‐acetylhenryoside (1), 2′,3′‐di‐O‐acetylhenryoside (2), 2′,6′‐di‐O‐acetylhenryoside (3), 2′,3′,6′‐tri‐O‐acetylhenryoside (4), 2′,3′,4′,6′‐tetra‐O‐acetylhenryoside (5), 2‐[(2,3‐di‐O‐acetyl‐β‐D‐glucopyranosyl)oxy]‐6‐hydroxybenzoic acid (6), and 6‐hydroxy‐2‐[(2,3,4,6‐tetra‐O‐acetyl‐β‐D‐glucopyranosyl)oxy]benzoic acid (7), were isolated from the leaves and stems of Viburnum cylindricum, along with 26 known compounds (henryoside=2‐(β‐D‐glucopyranosyloxy)‐6‐hydroxybenzoic acid [2‐(β‐D‐glucopyranosyloxy)phenyl]methyl ester). The structures of the new compounds were established on the basis of chemical and spectroscopic evidences.
Highly Efficient Synthesis of Thieno[2,3‐b]indole Derivatives
Authors: Boeini Hassan Zali
Published: September 2009

Thieno[2,3‐b]indole derivatives were efficiently prepared via the reaction of 1,3‐dihydro‐2H‐indole‐2‐thiones with α‐bromo‐substituted ketones or aldehydes and in the presence of Et3N (Scheme 2 and Table). The reaction took place under very mild conditions and in short times with good to excellent yields.
Alkyl‐Group Selection in an Acidic‐Surfactant‐Promoted Reaction of Homoallyl Alcohols and Aldehydes in Water
Authors: Hatakeyama Takanori , Chisaka Yuki , Kuroda Chiaki
Published: September 2009

The hydrophobic effect in the reaction of a homoallyl alcohol with an aldehyde (Yadav's reaction system) under aqueous conditions in the presence of an acidic surfactant was studied indicating the presence of the alkyl‐substituent effect, although not a dramatic one. The DBSA‐promoted reaction proceeds relatively faster when both the homoallyl alcohol and the aldehyde carry a cycloalkyl group (DBSA=4‐dodecylbenzenesulfonic acid). In contrast, the reaction of the substrates having an unbranched alkyl group is relatively more favorable in SDS/HCl than in DBSA (SDS=sodium dodecyl sulfate).
First Synthesis and Utilization of Oripavidine – A Concise and Efficient Route to Important Morphinans and Apomorphines
Authors: Sipos Attila , Berényi Sándor , Antus Sándor
Published: September 2009

The synthesis and transformation of oripavidine (8) offer an efficient and simple route to highly active dopamine agonist apomorphines and a variety of important 14β‐hydroxy‐morphinan derivatives. Natural origin thebaine (6), the starting compound of the procedure, was converted into its N‐{[1,2‐bis(ethoxycarbonyl)hydrazinyl]methyl} counterpart. L‐Selectride was found to be an efficient agent to perform a one‐pot O‐ and N‐deprotection at positions 3 and 17, respectively.
The Structure and Configuration of Novel Polycyclic Products Derived from an Alicyclic 1,5,9‐Trione and Binucleophiles
Authors: Kravchenko Natalia S. , Denisenko Vladimir A. , Akimova Taisia I.
Published: September 2009

As a continuation of our research of reactions with alicyclic 1,5,9‐trione 1 and its polycyclic form 2, we have studied their reactions with binucleophiles, e.g., phenylene‐1,2‐diamine and 2‐aminophenol, leading to novel N,O‐containing polycyclic compounds. Trione 1 formed double cyclization products 11 and 12 with 2‐aminophenol and triple cyclization product 15 with phenylene‐1,2‐diamine. Hemiacetal 2 and its dehydration product 5 reacted with binucleophiles through initial isomerization into the intermediate cyclic form 4 of trione 1. Thus, ketone 5 reacted with 2‐aminophenol stereoselectively unlike the hemiacetal 2. The structure and configuration of the reaction products were studied by using advanced spectroscopic techniques including 1D‐ and 2D‐NMR experiments.
Novel and Highly Effective Method for the Trimethylsilylation of Alcohols and Phenols with Hexamethyldisilazane (HMDS), Catalyzed by I2 Generated in situ Using Fe(NO3)3⋅9 H2O/NaI under Heterogeneous and Neutral Conditions
Authors: Khazaei Ardeshir , Rahmati Sadegh , Rostami Amin
Published: September 2009

Structurally diverse alcohols and phenols were trimethylsilylated in a clean and efficient reaction with hexamethyldisilazane (HMDS) based on the use of I2 generated in situ from Fe(NO3)3⋅9 H2O/NaI. The reaction occurs very rapid in good‐to‐high yield in CH2Cl2 at room temperature, and the use of toxic and corrosive molecular I2 is avoided.
Tri‐ and Bicyclic Taxoids from the Taiwanese Yew Taxus sumatrana
Authors: Luh Lon‐Je , El‐Razek Mohamed H. Abd , Liaw Chia‐Ching , Chen Chen‐Tung Arthur , Lin Yun‐Sheng , Kuo Yao‐Haur , Chien Ching‐Te , Shen Ya‐Ching
Published: September 2009

Five new taxoids, including a new 2(3→20)‐abeo‐taxane with a 6/10/6‐membered ring system and four 3,8‐seco‐taxanes having a 6/12‐membered ring system, were isolated from an acetone extract of the leaves and twigs of the Taiwanese yew (Taxus sumatrana, Taxaceae). The structures were established as 2α,7β,10α‐triacetoxy‐5α‐hydroxy‐2(3→20)‐abeo‐taxa‐4(20),11‐dien‐9,13‐dione (1), (3E,8E)‐2α,9,10β, 13α,20‐pentaacetoxy‐7β‐hydroxy‐3,8‐secotaxa‐3,8,11‐trien‐5‐one (2), (3E,8E)‐2α,9,10β,13α,20‐pentaacetoxy‐5α,7β‐dihydroxy‐3,8‐secotaxa‐3,8,11‐triene (3), (3E,8E)‐9,10β,13α‐triacetoxy‐2α,7β,20‐trihydroxy‐5α‐[(2E)‐cinnamoyloxy]‐3,8‐secotaxa‐3,8,11‐triene (4), and (3E,8E)‐2α,5α,7β,9,10β,13α‐hexaacetoxy‐20‐hydroxy‐3,8‐secotaxa‐3,8,11‐triene (5), respectively, on the basis 1D‐ and 2D‐NMR spectral analyses. The in vitro cytotoxic activity of compounds 1–5 against four human tumor cell lines, including HeLa (cervical epitheloid), WiDr (colon), Daoy (medulloblastoma), and Hep2 (liver carcinoma) tumor cells was evaluated. Whereas compounds 1–3 were inactive, the novel taxanes 4 and 5 showed significant cytotoxicity.
Structures of the Reactive Intermediates in Organocatalysis with Diarylprolinol Ethers
Authors: Grošelj Uroš , Seebach Dieter , Badine D. Michael , Schweizer W. Bernd , Beck Albert K. , Krossing Ingo , Klose Petra , Hayashi Yujiro , Uchimaru Tadafumi
Published: September 2009

Structures of the reactive intermediates (enamines and iminium ions) of organocatalysis with diarylprolinol derivatives have been determined. To this end, diarylprolinol methyl and silyl ethers, 1, and aldehydes, PhCH2CHO, tBuCH2CHO, PhCH=CHCHO, are condensed to the corresponding enamines, A and 3 (Scheme 2), and cinnamoylidene iminium salts, B and 4 (Scheme 3). These are isolated and fully characterized by melting/decomposition points, [α]D, elemental analysis, IR and NMR spectroscopy, and high‐resolution mass spectrometry (HR‐MS). Salts with BF4, PF6, SbF6, and the weakly coordinating Al[OC(CF3)3]4 anion were prepared. X‐Ray crystal structures of an enamine and of six iminium salts have been obtained and are described herein (Figs. 2 and 4–8, and Tables 2 and 7) and in a previous preliminary communication (Helv. Chim. Acta 2008, 91, 1999). According to the NMR spectra (in CDCl3, (D6)DMSO, (D6)acetone, or CD3OD; Table 1), the major isomers 4 of the iminium salts have (E)‐configuration of the exocyclic NC(1′) bond, but there are up to 11% of the (Z)‐isomer present in these solutions (Fig. 1). In all crystal structures, the iminium ions have (E)‐configuration, and the conformation around the exocyclic N‐CC‐O bond is synclinal‐exo (cf. C and L), with one of the phenyl groups over the pyrrolidine ring, and the RO group over the π‐system. One of the meta‐substituents (Me in 4b, CF3 in 4c and 4e) on a 3,5‐disubstituted phenyl group is also located in the space above the π‐system. DFT Calculations at various levels of theory (Tables 3–6) confirm that the experimentally determined structures (cf. Fig. 10) are by far (up to 8.3 kcal/mol) the most stable ones. Implications of the results with respect to the mechanism of organocatalysis by diarylprolinol derivatives are discussed.
The influence of combinations of oximes on the reactivating and therapeutic efficacy of antidotal treatment of tabun poisoning in rats and mice
Authors: Kassa Jiri , Karasova Jana Zdarova , Pavlikova Ruzena , Misik Jan , Caisberger Filip , Bajgar Jiri
Published: September 2009

The influence of the combination of oximes on the reactivating and therapeutic efficacy of antidotal treament of acute tabun poisoning was evaluated. The ability of two combinations of oximes (HI‐6 + obidoxime and HI‐6 + K203) to reactivate tabun‐inhibited acetylcholinesterase and reduce acute toxicity of tabun was compared with the reactivating and therapeutic efficacy of antidotal treatment involving single oxime (HI‐6, obidoxime, K203) using in vivo methods. Studies determining percentage of reactivation of tabun‐inhibited blood and tissue acetylcholinesterase in poisoned rats showed that the reactivating efficacy of both combinations of oximes is higher than the reactivating efficacy of the most effective individual oxime in blood and diaphragm and comparable with the reactivating effects of the most effective individual oxime in brain. Moreover, both combinations of oximes were found to be slightly more efficacious in the reduction of acute lethal toxic effects in tabun‐poisoned mice than the antidotal treatment involving individual oxime. A comparison of reactivating and therapeutic efficacy of individual oximes showed that the newly developed oxime K203 is slightly more effective than commonly used obidoxime and both of them are markedly more effective than the oxime HI‐6. Based on the obtained data, we can conclude that the antidotal treatment involving chosen combinations of oximes brings beneficial effects for the potency of antidotal treatment to reactivate tabun‐inhibited acetylcholinesterase in rats and to reduce acute toxicity of tabun in mice. Copyright © 2009 John Wiley & Sons, Ltd.