Showing papers on "Derivative (chemistry) published in 2012"

Physiochemical, Optical and Biological Activity of Chitosan-Chromone Derivative for Biomedical Applications

Abstract: This paper describes the physiochemical, optical and biological activity of chitosan-chromone derivative. The chitosan-chromone derivative gels were prepared by reacting chitosan with chromone-3-carbaldehyde, followed by solvent exchange, filtration and drying by evaporation. The identity of Schiff base was confirmed by UV-Vis absorption spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. The chitosan-chromone derivative was evaluated by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), photoluminescence (PL) and circular dichroism (CD). The CD spectrum showed the chitosan-chromone derivative had a secondary helical structure. Microbiological screening results demonstrated the chitosan-chromone derivative had antimicrobial activity against Escherichia coli bacteria. The chitosan-chromone derivative did not have any adverse effect on the cellular proliferation of mouse embryonic fibroblasts (MEF) and did not lead to cellular toxicity in MEFs. These results suggest that the chitosan-chromone derivative gels may open a new perspective in biomedical applications.

Polymorphs of an isoxazoline derivative

Abstract: The present invention relates to solid forms of certain benzamide isoxazoline insecticides, processes for their preparation, compositions comprising the solid forms and methods of their use as insecticides, acaricides, nematicides or molluscicides.

Chemistry of functionalized silylenes

Abstract: Recent years have witnessed important developments in organosilicon chemistry, courtesy to the high yield access of stable monomeric chlorosilylene (LSiCl, L = PhC(NtBu)2) and N-heterocyclic carbene (NHC) stabilized dichlorosilylene (L1SiCl2, L1 = 1,3-bis(2,6-iPr2C6H3)imidazol-2-ylidene) by dehydrochlorination technique using strong bases such as N-heterocyclic carbenes or LiN(SiMe3)2 as HCl scavenger. The chemistry of functionalized silylenes is markedly different from the previously reported dicoordinate silylenes. Their utility as synthons is well documented which paves the way for several striking compounds, e.g. monosilaoxiranes, CSi2P derivative, CSi3P cation, a dimer of silaisonitrile (Si2N2) with dicoordinate Si atoms etc. This study also unravels that these functionalized silylenes are proficient at activating phosphorus, and the functional group attached to the α-position of the silicon(II) centre plays a key role to determine the final product. The reaction of P4 with LSiCl affords a zwitterionic Si2P2 ring, while with LSiN(SiMe3)2 it gives an acyclic Si2P4 derivative. Another recent achievement in this field is the successful isolation of a valence isomer of disilyne known as the inter-connected bis-silylene. This perspective portrays the chemistry of functionalized silylenes which will attract great attention, heading for the further development of organosilicon chemistry.

Organic electroluminescent element

Abstract: PROBLEM TO BE SOLVED: To provide an organic electroluminescent element with high luminous efficiency, a long life and a small boost of drive voltage.SOLUTION: The organic electroluminescent element is formed by laminating: an anode; a hole injection layer containing a triaryl amine derivative including a triphenyl amine structure as a partial structure, and an electron accepting compound; a hole transport layer containing a polymer with a repeating unit represented by the formula (2); a luminescent layer containing a triaryl triazine derivative including a triphenyl triazine structure as a partial structure, and a phosphorescent body; and a cathode, in this order. (in the formula (2), Rto Rrepresent a silyl group which may be independently replaced by a hydrogen atom, a halogen atom, a cyano group, an alkyl group of carbon numbers 1 to 10, an alkoxy group of carbon numbers 1 to 10, an aryl group of carbon numbers 6 to 20, or an alkyl group of carbon numbers 1 to 10, respectively, and Rrepresents an alkyl group of carbon numbers 1 to 10, or an aryl group of carbon numbers 6 to 10.)

Bidirectional Photocontrol of Peptide Conformation with a Bridged Azobenzene Derivative

Abstract: It goes both ways: A thiol-reactive cross-linker based on a bridged azobenzene derivative permits photoreversible control of peptide conformation on irradiation with violet (407 nm) and green (500-550 nm) light (see picture) through isomerization of the cross-linker. The large separation of the absorbance bands of the cis (yellow) and trans (red) isomers enables complete bidirectional photoswitching.

A Crystalline Singlet Phosphinonitrene: A Nitrogen Atom–Transfer Agent

Abstract: A variety of transition metal–nitrido complexes (metallonitrenes) have been isolated and studied in the context of modeling intermediates in biological nitrogen fixation by the nitrogenase enzymes and the industrial Haber-Bosch hydrogenation of nitrogen gas into ammonia. In contrast, nonmetallic nitrenes have so far only been spectroscopically observed at low temperatures, despite their intermediacy in a range of organic reactions. Here, we report the synthesis of a bis(imidazolidin-2-iminato)phosphinonitrene, which is stable at room temperature in solution and can even be isolated in the solid state. The bonding between phosphorus and nitrogen is analogous to that observed for metallonitrenes. We also show that this nitrido phosphorus derivative can be used to transfer a nitrogen atom to organic fragments, a difficult task for transition metal–nitrido complexes.

Production method for 4, 4-difluoro-3,4-dihydroisoquinoline derivative

Abstract: Provided is a simple and efficient method for the large-scale production of a 4,4-difluoro-3,4-dihydroisoquinoline derivative. In the method for producing a 4,4-difluoro-3,4-dihydroisoquinoline derivative represented by general formula (1): a compound represented by general formula (2): is reacted with hydrogen fluoride.

Highly Efficient Inverted Polymer Solar Cells Based on an Alcohol Soluble Fullerene Derivative Interfacial Modification Material

Abstract: A phosphate group-containing bisadducts fullerene derivative bis-[6,6]-phenyl-C60-pentyl phosphoric diethyl ester (B-PCPO) has been developed as an indium tin oxide (ITO) interlayer material in inverted polymer solar cells. The B-PCPO possessed good alcohol solubility, n-type nature, good electron transporting ability, and ITO modification function simultaneously, and it was utilized as an ITO interlayer in solution-processed multilayer inverted bulk-heterojunction polymer solar cells to improve the electron transporting and collection. It was found that the B-PCPO interlayer could effectively decrease the work function of ITO and thereby enhance the electron collection of ITO electrode. The device studies showed that the resulting solar cells' efficiencies were significantly increased from 4.83% to 6.20% by using a B-PCPO interlayer, benefiting from the dramatic enhancement in open circuit voltage and moderate increase in fill factor. Our results provide a promising approach to improve the performance of...

Lectures on hydrodynamic fluctuations in relativistic theories

Abstract: These are pedagogical lecture notes on hydrodynamic fluctuations in normal relativistic fluids. The lectures discuss correlation functions of conserved densities in thermal equilibrium, interactions of the hydrodynamic modes, an effective action for viscous fluids, and the breakdown of the derivative expansion in hydrodynamics.

Cross coupling between sp3-carbon and sp3-carbon using a diborylmethane derivative at room temperature.

Abstract: A novel example of the Suzuki–Miyaura cross-coupling reaction between sp3-carbon and sp3-carbon is described. The reaction of a diborylmethane derivative with allyl halides or benzyl halides proceeded efficiently in the presence of appropriate Pd-catalysts at room temperature. The present approaches provide functionalized homoallylboronates and alkylboronates with excellent regio- and chemoselectivities.

A highly anti-selective asymmetric Henry reaction catalyzed by a chiral copper complex: applications to the syntheses of (+)-spisulosine and a pyrroloisoquinoline derivative.

Abstract: A highly anti-selective asymmetric Henry reaction has been developed, affording synthetically versatile β-nitroalcohols in a predominately anti-selective manner (mostly above 15:1) and excellent ee values (mostly above 95 %). Moreover, the anti-selective Henry reaction was carried out in the presence of water for the first time with up to 99 % ee. The catalytic mechanism was proposed based on the detection of the intermediates by extractive electrospray ionization mass spectrometry (EESI-MS). Furthermore, the anti adducts have been successfully transformed into the biochemically important (+)-spisulosine and a pyrroloisoquinoline derivative.

Ruthenium stilbenyl and diruthenium distyrylethene complexes: aspects of electron delocalization and electrocatalyzed isomerization of the Z-isomer.

Abstract: Regio- and stereoselective insertion of the terminal ethynyl functions of 4-ethynylstilbene, the E and Z isomers of 4,4′-bis(ethynylphenyl)ethene and a backbone-rigidified cyclohexenyl derivative of the Z isomer into the Ru–H bond of the complex RuClH(CO)(PiPr3)2 provides the corresponding vinyl ruthenium complexes, which have been characterized spectroscopically and by X-ray crystallography. Large red shifts of the UV/vis absorption bands evidence efficient incorporation of the vinyl metal subunit(s) into the conjugated π-system. All complexes oxidize at low potentials. The various oxidized forms of all complexes were generated and characterized by UV/vis/NIR, IR and EPR spectroscopies. These studies indicated electrocatalytic Z→E isomerization of the oxidized Z-distyrylethene complex Ru-Z2, which is prevented in its backbone-rigidified derivative Ru-Z2fix. The radical cations of the E and the configurationally stable cyclohexene-bridged Z-derivatives are spin-delocalized on the EPR time scale but charge...

Thermal post-synthetic modification of Al-MIL-53–COOH: systematic investigation of the decarboxylation and condensation reaction

Abstract: Aluminium trimellitate [Al(OH)(BDC–COOH)]·0.9H2O (1), the Al-MIL-53–COOH derivative, was discovered under solvothermal conditions using a high-throughput set-up suitable for microwave (MW)-assisted heating. The compound shows high structural flexibility. The large-pore (lp) form of the framework is obtained under large excess of H2O or after solvothermal treatment with N,N-dimethylformamide upon which [Al(OH)(BDC–COOH)]·0.7DMF (2) is obtained. Exposure of the water rich lp form of 1 to ambient conditions leads to the transformation to the narrow-pore (np) form. Thermal activation of both compounds results in the formation of the empty lp form and the activation of 1 was studied in detail by in situ IR-spectroscopy. Depending on the activation temperature and time two post-synthetic modification (PSM) processes are observed: the partial decarboxylation and the formation of acid anhydride groups. Thus at high temperatures and long activation times [Al(OH)(BDC–OCOCO–BDC)x/2(BDC)y] (x + y = 1) is formed. Upon cooling in air the anhydride functionality still remains intact, but the np form is obtained in air due to the adsorption of H2O molecules. Sorption measurements of 1 confirm a preference for polar gases like H2O and CO2 in comparison to N2, H2, and CH4. The N2 capacity depends strongly on the degree of decarboxylation.

Oxadiazole sulfone compound for controlling bacterial crop diseases

Abstract: The invention discloses oxadiazole sulfone compound used for controlling bacterial crop diseases, in particular to an oxadiazole-sulfone containing derivative. The oxadiazole sulfone compound has the following general formula, wherein Rn and R2 are defined as in the description. A part of the oxadiazole sulfone compound has good speckled, withered and blighted bacterial crop disease inhibiting activity, and the oxadiazole sulfone compound has a wide application prospect.

[16]Cloverphene: a clover-shaped cata-condensed nanographene with sixteen fused benzene rings.

Abstract: Cloverphenes are graphene-type polyarenes, the structures of which resemble the threefold symmetry of clover leafs. In their Communication (10.1002/anie.201104935), D. Pena and co-workers present the synthesis and properties of a nanosized [16]cloverphene derivative, which consists of 16 fused benzene rings (22 benzene rings in total) and 102 sp(2) -hybridized atoms. The synthesis involves sequential [4+2] and [2+2+2] aryne cycloadditions.

Design and synthesis of novel DFG-out RAF/vascular endothelial growth factor receptor 2 (VEGFR2) inhibitors. 1. Exploration of [5,6]-fused bicyclic scaffolds.

Abstract: To develop RAF/VEGFR2 inhibitors that bind to the inactive DFG-out conformation, we conducted structure-based drug design using the X-ray cocrystal structures of BRAF, starting from an imidazo[1,2-b]pyridazine derivative. We designed various [5,6]-fused bicyclic scaffolds (ring A, 1-6) possessing an anilide group that forms two hydrogen bond interactions with Cys532. Stabilizing the planarity of this anilide and the nitrogen atom on the six-membered ring of the scaffold was critical for enhancing BRAF inhibition. The selected [1,3]thiazolo[5,4-b]pyridine derivative 6d showed potent inhibitory activity in both BRAF and VEGFR2. Solid dispersion formulation of 6d (6d-SD) maximized its oral absorption in rats and showed significant suppression of ERK1/2 phosphorylation in an A375 melanoma xenograft model in rats by single administration. Tumor regression (T/C = -7.0%) in twice-daily repetitive studies at a dose of 50 mg/kg in rats confirmed that 6d is a promising RAF/VEGFR2 inhibitor showing potent anticancer activity.

Modification of luminescent properties of a coumarin derivative by formation of multi-component crystals

Abstract: Four new multi-component crystals of a carboxylic acid derivative of coumarin have been synthesised based on a hydrogen bond synthon approach.

Purinone derivative hydrochloride

Abstract: The purinone derivative 6-amino-9-[(3R)-1-(2-butynoyl)-3-pyrrolidinyl]-7-(4-phenoxyphenyl)-7,9-dihydro-8H-purin-8-one hydrochloride has Btk-selective inhibitory activity and, in addition to having excellent metabolic stability, it is a compound that exhibits a high level of solubility and absorption with respect to the free base and can be crystallized, hence it can serve as a therapeutic agent for diseases involving B cells and mast cells.

Application of Derivative Voltammetry in the Analysis of Methanol Oxidation Reaction

Abstract: Application of derivative voltammetry to methanol oxidation reaction (MOR) has been studied, and its advantage in the analysis of various aspects of MOR with regard to direct methanol fuel cell has been delineated. The derivative technique of voltammetric analysis was employed in evaluating and comparing MOR activities of carbon-supported mono-, bi-, and tri-metallic electrocatalysts. Significant enhancement in the accuracy of estimating voltammetric peak potential and onset potential of methanol oxidation current can be achieved in derivative voltammetry. Furthermore, the better signal-to-noise ratio of derivative voltammetry practically eliminates charging current. From a mechanistic point of view, derivative voltammetry is highly sensitive in resolving a peak due to parallel path mechanism. Electrochemical stability of anode catalysts can be better evaluated and monitored employing derivative voltammetry. Nevertheless, the derivative technique is simple and does not require further instrumentation or c...