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Derivatives
Kinds of Derivatives Terms modified by Derivatives Selected AbstractsA NOTE ON SAMPLING DESIGNS FOR RANDOM PROCESSES WITH NO QUADRATIC MEAN DERIVATIVEAUSTRALIAN & NEW ZEALAND JOURNAL OF STATISTICS, Issue 3 2006Bhramar Mukherjee Summary Several authors have previously discussed the problem of obtaining asymptotically optimal design sequences for estimating the path of a stochastic process using intricate analytical techniques. In this note, an alternative treatment is provided for obtaining asymptotically optimal sampling designs for estimating the path of a second order stochastic process with known covariance function. A simple estimator is proposed which is asymptotically equivalent to the full-fledged best linear unbiased estimator and the entire asymptotics are carried out through studying this estimator. The current approach lends an intuitive statistical perspective to the entire estimation problem. [source] CALCIUM ANTAGONIST PROPERTY OF CPU228, A DOFETILIDE DERIVATIVE, CONTRIBUTES TO ITS LOW INCIDENCE OF TORSADES DE POINTES IN RABBITSCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 4 2007Zhi-Jiang Huang SUMMARY 1Torsades de pointes (TDP) is a severe adverse effect during the clinical use of dofetilide, a selective blocker of the rapid component of the delayed rectifier potassium channel (IKr). The present study was designed to test whether CPU228, a derivative of dofetilide with calcium (Ca2+) antagonist properties, could reduce TDP without reducing the blockade of IKr. 2The incidence of TDP in a rabbit model and the effective refractory period (ERP) were measured and compared for dofetilide and CPU228. Suppression of IKr and the L-type Ca2+ current (ICa,L) and the Ca2+ transients of isolated cardiomyocytes were investigated by whole-cell patch-clamp and Fluo-3 dye spectrophotometry. 3The incidence of TDP was greatly reduced by CPU228 relative to dofetilide, occurring in only one of six rabbits compared with five of six rabbits following dofetilide (P < 0.05). In isolated atria, prolongation of ERP by CPU228 was less than that of dofetilide and no reverse frequency dependence was observed. Negative inotropism by CPU228 was significant against positive inotropism by dofetilide. CPU228 inhibited both IKr and ICa,L currents and the IC50 for ICa,L inhibition was 0.909 µmol/L. At 3 µmol/L, CPU228 significantly suppressed the Ca2+ transients. 4CPU228 is able to block ICa,L, contributing to decreased TDP, while also blocking IKr activity. By combined blockade of IKr and ICa,L, CPU228 shares the property of complex Class III anti-arrhythmic agents. [source] Construction of L -Lysine Sensor by Layer-by-Layer Adsorption of L -Lysine 6-Dehydrogenase and Ferrocene-Labeled High Molecular Weight Coenzyme Derivative on Gold ElectrodeELECTROANALYSIS, Issue 24 2008Haitao Zheng Abstract A ferrocene-labeled high molecular weight coenzyme derivative (PEI-Fc-NAD) and a thermostable NAD-dependent L -lysine 6-dehydrogenase (LysDH) from thermophile Geobacillus stearothermophilus were used to fabricate a reagentless L -lysine sensor. Both LysDH and PEI-Fc-NAD were immobilized on the surface of a gold electrode by consecutive layer-by-layer adsorption (LBL) technique. By the simple LBL method, the reagentless L -lysine sensor, with co-immobilization of the mediator, coenzyme, and enzyme was obtained, which exhibited current response to L -lysine without the addition of native coenzyme to the analysis system. The amperometric response of the sensor was dependent on the applied potential, bilayer number of PEI-Fc-NAD/LysDH, and substrate concentration. A linear current response, proportional to L -lysine concentration in the range of 1,120,mM was observed. The response of the sensor to L -lysine was decreased by 30% from the original activity after one month storage. [source] Voltammetric Reduction of a 4-Nitroimidazole Derivative on a Multiwalled Carbon Nanotubes Modified Glassy Carbon ElectrodeELECTROANALYSIS, Issue 13 2008P. Jara-Ulloa Abstract We report the electrochemical behavior of a 4-nitroimidazole derivative, 1-methyl-4-nitro-2-hydroxymethylimidazole (4-NImMeOH), on glassy carbon electrode (GCE) modified with multiwalled carbon nanotubes (MWCNT). As dispersing agents, dimethylformamide (DMF) and water were used. The electrochemical response of the resulting electrodes was evaluated using linear sweep, cyclic and square-wave voltammetry (LSV, CV and SWV). Several parameters such as medium pH, nature and concentration of the CNTs dispersion and accumulation time were tested. The optimal conditions determined for obtain better response were: pH,2, dispersion concentration=4,mg/mL of CNT in water, accumulation time=7,min. The MWCNT-modified GCE exhibited attractive electrochemical properties producing enhanced currents with a significant reduction in the overpotential and good signal-to-noise characteristics, in comparison with the bare GCE. The modified electrode is highly repeatable for consecutive measurements, reaching a variation coefficient of 2.9% for ten consecutive runs. [source] Facilitated Transfer of Alkali Metal Ions by a Tetraester Derivative of Thiacalix[4]arene at the Liquid,Liquid InterfaceELECTROANALYSIS, Issue 12 2008Akgemci, Emine Guler Abstract The facilitated transfer of alkali metal ions (Na+, K+, Rb+, and Cs+) by 25,26,27,28-tetraethoxycarbonylmethoxy-thiacalix[4]arene across the water/1,2-dichloroethane interface was investigated by cyclic voltammetry. The dependence of the half-wave transfer potential on the metal and ligand concentrations was used to formulate the stoichiometric ratio and to evaluate the association constants of the complexes formed between ionophore and metal ions. While the facilitated transfer of Li+ ion was not observed across the water/1,2-dichloroethane interface, the facilitated transfers were observed by formation of 1,:,1 (metal:ionophore) complex for Na+, K+, and Rb+ ions except for Cs+ ion. In the case of Cs+ a 1,:,2 (metal:ionophore) complex was obtained from its special electrochemical response to the variation of ligand concentrations in the organic phase. The logarithms of the complex association constants, for facilitated transfer of Na+, K+, Rb+, and Cs+, were estimated as 6.52, 7.75, 7.91 (log ,1°), and 8.36 (log ,2°), respectively. [source] A Bis-Oxime Derivative of Diaza-18-Crown-6 as an Ionophore for Silver IonELECTROANALYSIS, Issue 11 2005Michael Abstract A new pendant-arm derivative of diaza-18-crown-6, containing two oxime donor groups, has been synthesized and incorporated into a polyvinyl chloride (PVC) membrane ion-selective electrode. The electrode shows selectivity for Ag+ ion, with a near Nernstian response. Pb2+, Cu2+, Hg2+, and Tl+ are major interfering ions, with Cd2+ having minor interference. The electrode shows no potentiometric response for the ions Mg2+, Al3+, K+, Ca2+, Ni2+, Fe3+, and La3+, and is responsive to H+ at pH<6. [source] Synthesis of Enantiopure Ruthenium Tricarbonyl Complexes of a Bicyclic Cyclopentadienone DerivativeEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2008Min-soo Kim Abstract (,)-Menthone was converted stereoselectively into 3-menthylpropargyl alcohol 8 in several steps and subsequently converted into enantiopure cyclopentadienone ruthenium carbonyl complexes. In the malonate cases, ruthenacycle 15 was also formed during the cyclization reaction. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Reactions of GaCp* with a Hemilabile Derivative of Rh6(CO)16 , Synthesis and Structural Characterization of Two Novel Heterometallic Clusters: Rh6(CO)13(,,,3 -Ph2PC2H3)(,3 -GaCp*) and Rh6(CO)13(,1 -Ph2PC2H3)(,3 -GaCp*)2EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2007Elena V. Grachova Abstract The reaction of Rh6(CO)14(Ph2PCH=CH2) with a twofold excess of GaCp* (Cp* = C5Me5) affords two novel heterometallic clusters Rh6(CO)13(,,,3 -Ph2PC2H3)(,3 -GaCp*) (1) and Rh6(CO)13(,1 -Ph2PC2H3)(,3 -GaCp*)2 (2) in a moderate yield. The hemilabile behavior of coordinated diphenylvinylphosphane in the starting cluster allows the easy insertion of GaCp* into the cluster coordination sphere, which eventually gives the cluster 1 with face-bridging coordination of the gallium fragment and the phosphane ligand recoordinated in an edge-bridging position. The further substitution of the vinyl function in 1 for the second GaCp* ligand affords cluster 2, where recoordination of the double bond is blocked by steric hindrance from adjacent GaCp* fragments. Both clusters were structurally characterized by X-ray crystallography in the solid state and by IR and NMR spectroscopy in solution. Hemilability of diphenylvinylphosphane in 1 was independently confirmed by the cluster reaction with CO, which gives the Rh6(CO)14(,1 -Ph2PC2H3)(GaCp*) adduct (3) with the phosphane ligand only coordinated through the phosphorus atom. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Preparation and Structure Determination of a Stable cis -Bis-,-homobenzene Derivative,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2010Dieter Wullbrandt Abstract By cyclopropanation of tetramethyl[2.2]paracyclophane 9 the tetramethylene adduct 10 has been prepared. This hydrocarbon is the first stable cis -bis-,-homobenzene for which a structure has been determined by X-ray diffraction. [source] Unusual Magnesium Chloride Catalyzed Non-Evans anti -Aldol Reactions of an Enolizable L -Threose DerivativeEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 34 2007James McNulty Abstract The magnesium chloride catalyzed anti -aldol reaction of phenyl acetate derived oxazolidinones proceeds readily with enolizable L -threose derivative 8 to provide anti -aldol adducts in high yields and with very high diastereoselectivities. The reaction is also efficient with aromatic aldehydes and provides slightly lower diastereoselectivities. This extension allows access to stereochemically defined fragments applicable to the synthesis of alkaloid and phenylpropanoid derivatives.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Kinetics of (Porphyrin)manganese(III)-Catalyzed Olefin Epoxidation with a Soluble Iodosylbenzene DerivativeEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 12 2006James P. Collman Abstract We examined the kinetics of a well-behaved system for homogeneous porphyrin-catalyzed olefin epoxidation with a soluble iodosylbenzene derivative 1 as the terminal oxidant and Mn(TPFPP)Cl (2) as the catalyst. The epoxidation rates were measured by using the initial rate method, and the epoxidation products were determined by gas chromatography. The epoxidation rate was found to be first order with respect to the porphyrin catalyst and zero order on the terminal oxidant. In addition, we found the rate law to be sensitive to the nature and concentration of olefin substrates. Saturation kinetics were observed with all olefin substrates at high olefin concentrations, and the kinetic data are consistent with a Michaelis,Menten kinetic model. According to the observed saturation kinetic results, we propose that there is a complexation between the active oxidant and the substrate, and the rate-determining step is thought to be the breakdown of this putative substrate,oxidant complex that generates the epoxidation products and the resting state porphyrin catalyst. Competitive epoxidations further indicate a reversible complexation of the active oxidant and the olefin substrate. The activation parameters ,H, and ,S, for the oxygen-transfer process (k2) in the cis -cyclooctene epoxidation were determined to be 12.3,±,0.9 kcal,mol,1 and,15.6,±,3.2 cal,mol,1,K,1, respectively. In addition, the Hammett constant ,+ was measured for the epoxidation of para -substituted styrenes, and the value of ,0.27,±,0.04 is too low to be consistent with the involvement of a discrete carbocation in the transition state. We also prepared a (porphyrin)manganese catalyst immobilized on silica support, and found the epoxidation of cis -cyclooctene catalyzed by this heterogeneous catalyst proceeds at virtually the same turnover frequency as by the homogeneous porphyrin catalyst. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] The Superbase-Mediated Pairwise Substitution of the 2,2,- and 6,6,-Positions in a Biphenyl DerivativeEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 5 2004Manfred Schlosser Abstract The superbasic mixture of butyllithium and potassium tert -butoxide is powerful enough to enable the double proton abstraction from one ortho and one ortho, position of 4,4,-di- tert -butylbiphenyl. In this way, a series of functionalized derivatives becomes readily accessible, among them 4,4,-di- tert -butylbiphenyldiyl-2,2,-dicarboxylic acid (2a) and 4,4,-di- tert -butylbiphenyl-2,2,-diol (2d). The latter compound can be subjected again to a superbase-promoted double metalation, thus giving rise to 2,2,,6,6,-tetrasubstituted biphenyl derivatives. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] On the Way to Glycoprocessing Inhibitors , Synthesis of an Imidazolo-Nectrisine-Phosphono Acid Derivative: A Potential Glycosyltranferase InhibitorEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2003Théophile Tschamber Abstract Assuming the transition state of glycosyltransferase inhibitors to be similar to those encountered with potent glycosidase inhibitors , i.e. a flattened conformation with a positively charged anomeric centre , we worked out a synthesis of the D - arabino -configured phosphonic acid target molecule 2 derived from an imidazolo-sugar. The key synthetic intermediate is the linear imidazolo L - xylo compound 10 which could be obtained, either from L - threo precursor 6 by a coupling reaction with imidazole derivative 5, or from L -sorbose. A multi-step and site specific iodination of 10 gave the mono-iodo- L - xylo derivative 14 which was cyclised to the D - arabino -configured bicyclic azasugar 15. Phosphorylation of the Grignard derivative of the latter, followed by mono-esterification with citronellol along with some protection-deprotection steps led to target molecule 2. The potential inhibitor 2 is supposed to be protonated at its most basic N atom by a carboxylic acid residue in the arabinosyl-transferase active site. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Influence of Molecular Weight on the Performance of Organic Solar Cells Based on a Fluorene DerivativeADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Christian Müller Abstract The performance of organic photovoltaic (OPV) bulk-heterojunction blends comprising a liquid-crystalline fluorene derivative and a small-molecular fullerene is found to increase asymptotically with the degree of polymerization of the former. Similar to various thermodynamic transition temperatures as well as the light absorbance of the fluorene moiety, the photocurrent extracted from OPV devices is found to strongly vary with increasing oligomer size up to a number average molecular weight, Mn,,,10,kg,mol,1, but is rendered less chain-length dependent for higher Mn as the fluorene derivative gradually adopts polymeric behavior. [source] Highly Efficient Red Phosphorescent OLEDs based on Non-Conjugated Silicon-Cored Spirobifluorene Derivative Doped with Ir-ComplexesADVANCED FUNCTIONAL MATERIALS, Issue 3 2009Yi-Yeol Lyu Abstract A novel host material containing silicon-cored spirobifluorene derivative (SBP-TS-PSB), is designed, synthesized, and characterized for red phosphorescent organic light-emitting diodes (OLEDs). The SBP-TS-PSB has excellent thermal and morphological stabilities and exhibits high electroluminescence (EL) efficiency as a host for the red phosphorescent OLEDs. The electrophosphorescence properties of the devices using SBP-TS-PSB as the host and red phosphorescent iridium (III) complexes as the emitter are investigated and these devices exhibit higher EL performances compared with the reference devices with 4,4,- N,N,-dicarbazole-biphenyl (CBP) as a host material; for example, a (piq)2Ir(acac)-doped SBP-TS-PSB device shows maximum external quantum efficiency of ,ext,=,14.6%, power efficiency of 10.3 lm W,1 and Commission International de L'Eclairage color coordinates (0.68, 0.32) at J,=,1.5,mA cm,2, while the device with the CBP host shows maximum ,ext,=,12.1%. These high performances can be mainly explained by efficient triplet energy transfer from the host to the guests and improved charge balance attributable to the bipolar characteristics of the spirobifluorene group. [source] Polymer Solar Cells Based on a Low-Bandgap Fluorene Copolymer and a Fullerene Derivative with Photocurrent Extended to 850,nm,ADVANCED FUNCTIONAL MATERIALS, Issue 5 2005F. Zhang Abstract Polymer solar cells have been fabricated from a recently synthesized low band-gap alternating polyfluorene copolymer, APFO-Green2, combined with [6,6]-phenyl-C61 -butyric acid methyl ester (PCBM) from organic solutions. External quantum efficiencies (EQEs) of the solar cells show an onset at 850,nm and a peak of >,10,% located at 650,nm, which corresponds to the extended absorption spectrum of the polymer. Photocurrent of 3.0,mA,cm,2, photovoltage of 0.78,V, and power conversion efficiency of 0.9,% have been achieved in solar cells based on this new low-bandgap polymer under the illumination of air mass,1.5 (AM,1.5) (1000,W,m,2) from a solar simulator. [source] Paxillamide: a Novel Phytosphingosine Derivative from the Fruiting Bodies of Paxillus panuoidesHELVETICA CHIMICA ACTA, Issue 6 2004Jin-Ming Gao The new phytosphingosine-type ceramide 1, named paxillamide (=2,3-dihydroxy- N -[(1S,2S,3R)-2,3-dihydroxy-1-(hydroxymethyl)heptadecyl]tetracosanamide), was isolated from the CHCl3/MeOH extract of the fruiting bodies of the Basidiomycete Paxillus panuoides, and its structure was elucidated by spectroscopic and chemical methods. [source] Reaction of Phenanthrene-9,10-dione with Phenanthrene-9,10-diol: Synthesis and Characterization of the First ortho -Quinhydrone DerivativeHELVETICA CHIMICA ACTA, Issue 4 2004Fausto Calderazzo Treatment of phenanthrene-9,10-dione (PQ) with phenanthrene-9,10-diol (PQH2), as prepared by catalytic hydrogenation of PQ, in toluene solution or in the solid state afforded crystalline ,9,10-phenanthrenequinhydrone' (PQH), the first example of an ortho -quinhydrone. PQH was characterized by analytical and spectroscopic methods, including X-ray and CP/MAS 13C-NMR analyses. The crystal structure of PQH showed pairs of planar molecules linked by H-bonds and organized in columns parallel to the crystallographic axis a. The solid-state structure of PQH was compared with those of the parent compounds, PQ and PQH2, the latter being reported for the first time. PQH was found to be stable in the solid state only, the components PQ and PQH2 being formed upon dissolution in media of even low polarity such as toluene. [source] Solution-Processed Solid Solution of a Novel Carbazole Derivative for High-Performance Blue Phosphorescent Organic Light-Emitting DiodesADVANCED MATERIALS, Issue 37 2010Shanghui Ye Blue light: Incorporation of two fluorenyl rings into a phenyl group at the C9 position of fluorene builds a bulky and rigidly tetrahedral framework, which is functionalized by two carbazole groups. This molecule possesses excellent thermal and morphological stability, miscibility to the phosphorescent dopant, and high triplet energy, leading to narrow blue phosphorescent emission. [source] High-Performance Organic Single-Crystal Transistors and Digital Inverters of an Anthracene DerivativeADVANCED MATERIALS, Issue 36 2009Lang Jiang Single-crystal disks of di(phenylvinyl) anthracene, micro- or nanometer-sized and flexible, are produced by physical vapor transport. Subsequently, single- crystal transistors are fabricated by the organic ribbon mask method and integrated to produce high-performance inverters. The mobility of the transistors, the mobility anisotropy along different crystal axes of the disks, and the maximum gain of the inverters are reported. [source] A New Poly(thienylenevinylene) Derivative with High Mobility and Oxidative Stability for Organic Thin-Film Transistors and Solar CellsADVANCED MATERIALS, Issue 27 2009Bogyu Lim A novel thiophene-thienylenevinylene copolymer is synthesized and evaluated for use in organic field-effect transistors and organic solar cells. PETV12T shows good solution processability and high structural organization after annealing. Organic thin-film transistors based on the polymer exhibit high mobility and a high resistance to oxidation. In addition, PETV12T shows potential as an electron donor in bulk heterojunction solar cells. [source] Wide Blue Phase Range in a Hydrogen-Bonded Self-Assembled Complex of Chiral Fluoro-Substituted Benzoic Acid and Pyridine DerivativeADVANCED MATERIALS, Issue 20 2009Wanli He A blue phase with a broad temperature range of about 23.0 °C is easily achieved in a hydrogen-bonded self-assembled complex of chiral fluoro-substituted benzoic acid and pyridine derivative. The success in extending the temperature of blue phase indicates that the hydrogen-bonded self-assembly is a promising new approach to broaden the temperature range of blue phases and to investigate the mystery of blue phases. [source] Organic Single-Crystalline Ribbons of a Rigid "H"-type Anthracene Derivative and High-Performance, Short-Channel Field-Effect Transistors of Individual Micro/Nanometer-Sized Ribbons Fabricated by an "Organic Ribbon Mask" Technique,ADVANCED MATERIALS, Issue 14 2008Lang Jiang The synthesis of a rigid, planar H-type anthracene derivative is described. Single-crystalline ribbons at micro- and nanometer sizes can be controllably produced and transistors based on an individual ribbon can be fabricated in situ through a newly developed "organic ribbon mask" method, in which the channel length of the transistors can be easily scaled down to sub-micrometer level. [source] High Ambipolar Mobility in a Highly Ordered Smectic Phase of a Dialkylphenylterthiophene Derivative That Can Be Applied to Solution-Processed Organic Field-Effect Transistors,ADVANCED MATERIALS, Issue 3 2007M. Funahashi A phenylterthiophene derivative that exhibits a highly ordered smectic phase around room temperature is synthesized. In the bulk of the smectic phase, ambipolar carrier transport is observed and electron mobility exceeds 0.2,cm2,V,1,s,1. Thin-film transistors (see the AFM image in the figure) are fabricated by a spin-coating method and exhibit p-type operation, a field-effect mobility of 0.02,cm2,V,1,s,1, and an on/off ratio of 106. [source] High-Performance Polymer Solar Cells of an Alternating Polyfluorene Copolymer and a Fullerene Derivative,ADVANCED MATERIALS, Issue 12 2003M. Svensson Solar cells prepared using the alternating copolymer shown in the Figure blended with a C60 derivative (PCBM) are demonstrated to have a high performance, with a power conversion efficiency of 2.2,% under simulated solar light. The molecular weight of the polymer is low due to limited solubility, and films of the polymer exhibit red-shifted absorption. [source] Pyrrolidine-Camphor Derivative as an Organocatalyst for Asymmetic Michael Additions of ,,,-Disubstituted Aldehydes to ,-Nitroalkenes: Construction of Quaternary Carbon-Bearing Aldehydes under Solvent-Free ConditionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009Chihliang Chang Abstract A novel pyrrolidine-camphor organocatalyst 3 was designed, synthesized and proven to be an efficient catalyst for the asymmetric Michael reaction. Treatment of ,,,-disubstituted aldehydes with ,-nitroalkenes in the presence of 20,mol% organocatalyst 3 and 20,mol% benzoic acid under solvent-free conditions provided the desired Michael product possessing an all-carbon quaternary center with high chemical yields (up to 99% yield) and high levels of enantioselectivities (up to 95% ee). [source] Titanium(IV)/Tridentate BINOL Derivative as Catalyst for meso -Aziridine Ring-Opening Reactions: High Enantioselectivity, Strong Positive Non-Linear Effect and Structural CharacterizationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009Rongmin Yu Abstract A titanium-based chiral Lewis acid was found to be effective for the ring-opening reactions of meso -aziridines with aniline nucleophiles. The products were generally isolated in high yields and with high to excellent enantioselectivity. The catalytic system was studied by X-ray single crystal analysis. In experiments on non-linear effects a strong non-linear effect of the catalyst system was observed. [source] New Synthetic Approach to a [1.1.6] Metapara Cyclophane Derivative via Suzuki,Miyaura Cross-Coupling and Ring-Closing Metathesis,ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2005Sambasivarao Kotha Abstract The synthesis of a [1.1.6] metapara cyclophane derivative, 1,5(1,4),3(1,3)-tribenzenacycloundecaphan-8-ene-6,11-dione, has been achieved via the Suzuki,Miyaura cross-coupling of ,,,,-dibromo- m -xylene with an arylboronic acid derivative followed by an allylation and ring-closing metathesis reaction sequence. [source] Chemoenzymatic Route to Both Enantiomers of a 1-Isopropyl-3a-methyloctahydroinden-4-one Derivative: A Synthetic Intermediate for Sesqui- and DiterpenoidsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2005Shigeo Fujieda Abstract On the way to a chemoenzymatic synthesis of a key intermediate for sesquiterpenoids and diterpenoids, 2-methyl-2-(4-methyl-3-oxopentyl)-1,3-cyclohexanedione was reduced with the whole cells of yeast biocatalysts. Torulaspora delbrueckii NBRC10921 reduced a cyclic ketone of three carbonyl groups in an enantiofacially selective manner (re -face attack), but there was poor enantiotopic group selectivity between two carbonyl groups on the cyclohexane ring to yield a mixture of diastereomeric products. Candida floricola IAM13115 reduced mainly the pro -(R) carbonyl group. In contrast, the reduction proceeded in an enantiofacially poorly selective manner to give another set of diastereomeric products. In both cases, another carbonyl group on the side chain worked as a ,trapping arm' of the resulting secondary alcohol. The diastereomeric products were effectively separated as the ,syn' or ,cis' isomer exclusively exist in the intramolecular hemiacetal structure, while ,anti' or ,trans' isomer being an equilibrated mixture of cyclic hemiacetal and open-chain hydroxyketone (ca. 0.7,:,1). Starting separately from the enantiomerically enriched products as above, both enantiomers of the target compound, a key intermediate for terpenoids, were efficiently prepared via stereoselective ring closure under pinacol coupling reaction conditions. Furthermore, a daucane sesquiterpene intermediate, a hydroazulene derivative, was provided after one-carbon homologation of the six-membered ring. [source] Studies on Preparation and Fluorescent Properties of a Novel Photo-Sensitive Nanoparticle Composed of Europium Ion and Cinnamic Acid DerivativeMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 23 2009Dongjian Shi Abstract A novel fluorescent and photo-sensitive nanoparticle was self-assembled from an europium-based random copolymer, europium coordinated poly(methylacrylic acid)- co -poly(cinnamyl acrylate) (PMCFA-Eu3+), which was synthesized from methylacrylic acid (MAA), and Eu3+ -cinnamyl acrylate derivative (CFA) by radical polymerization. DLS and TEM results indicated the formation of spherical nanoparticles with 120,nm in diameter. The PMCFA-Eu3+ complex showed stronger fluorescence than Eu3+, indicating the effective energy transferred from the ligand to Eu3+. Moreover, the photo-crosslinking of the cinnamate groups induced a decrease in the diameter and an increase in the fluorescent properties of the PMCFA-Eu3+ nanoparticles. This functional nanoparticle might be useful as a carrier and a fluorescence probe in biomedical and fluorescent fields. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||