The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform

Antonio G Gonzalez - One of the best experts on this subject based on the ideXlab platform.

Rafael Gramage-doria - One of the best experts on this subject based on the ideXlab platform.

  • Site-selective Ru-catalyzed C-H bond alkenylation with biologically relevant isoindolinones: a case of catalyst performance controlled by subtle stereo-electronic effects of the weak directing group
    Catalysis Science & Technology, 2019
    Co-Authors: Yu-chao Yuan, Christian Bruneau, Thierry Roisnel, Rafael Gramage-doria
    Abstract:

    The first use of biologically relevant isoindolinones as weak directing groups in transition metal-catalyzed carbon-carbon bond formation via C-H bond functionalization is presented. Notably, besides the presence of two aromatic C-H sites available for functionalization, selective mono-alkenylation in the ortho-position with respect to the nitrogen atom were achieved with a readily available ruthenium catalyst. The scalability, versatility and high functional group tolerance of the catalysis enabled the late-stage functionalization of biologically relevant Indoprofen and further derivatizations. Preliminary mechanistic studies indicate (1) the ease of the C-H bond activation step, (2) the key role of the carbonyl group as a weak directing group throughout the catalytic cycle and (3) the unexpected subtle differences associated between cyclic amides and imides as weak directing groups in ruthenium-catalyzed C-H bond alkenylation reactions. The isolation and role of an unprecedented off-cycle ruthenium complex is discussed as well.

Nadia Chouinilalanne - One of the best experts on this subject based on the ideXlab platform.

  • correlation of cyclic voltammetry behaviour and photooxidative properties of Indoprofen and its photoproducts
    Electrochimica Acta, 2006
    Co-Authors: Paullouis Fabre, Laure Latapie, Arielle Noirot, Nadia Chouinilalanne
    Abstract:

    Abstract The electrochemical behaviour of Indoprofen (INP) and its photoproducts was investigated in acetonitrile containing tetrabutylammonium hexafluorophosphate at a Pt or Cv ultramicro-electrodes. These photosensitizers (PS) undergo irreversible oxidation yielding at first a radical cation PS + and more or less reversible reductions through monoelectronic exchange involving a radical anion PS −. By varying the potential scan speed, the stabilities of the radical anions were evaluated. The determination of the redox potential and Rehm–Weller's equation shows the high exergonicity of the oxidative photodamagings whatever is the compound PS. The difference in DNA photosensitizing properties could rather be related to a kinetic control and then to the relative stabilities of the radical anions PS −. Cyclic voltammetry was found powerful in order to get a new insight in the photosensitizing properties of drugs.

  • dna photosensitization by Indoprofen is dna damage photoinduced by Indoprofen or by its photoproducts
    Photochemical and Photobiological Sciences, 2004
    Co-Authors: Jerome Trzcionka, Virginie Lhiaubetvallet, Nadia Chouinilalanne
    Abstract:

    The in vitro photosensitizing activity of Indoprofen, a non-steroidal anti-inflammatory drug, toward DNA has been studied by gel sequencing experiments using 32P-end labelled synthetic oligonucleotides in phosphate buffered solution. Upon irradiation at λ > 320 nm, piperidine-sensitive lesions were induced in single- and double-stranded DNA, exclusively at the position of guanine bases. In single-stranded DNA, all G sites were modified. This pattern of photooxidative damage without isotopic effect in deuterium oxide, is characteristic of a Type I mechanism involving electron transfer from the base to the excited drug. In duplex DNA, a Type I process was also observed since selective DNA breakage occurred with high selectivity at 5′-G of a 5′-GG-3′sequence. When the oligonucleotide displays TT sites, an energy transfer process becomes predominant, giving rise to the formation of thymine dimers as evidenced by using T4 endonuclease V. Moreover, the methyl ester of Indoprofen has been synthesized in order to study the influence of the Indoprofen photochemical properties in DNA photosensitization. The poor efficiency of this compound shows that the drug itself is not directly implicated in DNA photodamage and seems to imply the involvement of Indoprofen photoproducts.

  • photochemical and photophysical properties of Indoprofen
    Photochemistry and Photobiology, 2003
    Co-Authors: Virginie Lhiaubetvallet, Jerome Trzcionka, Susana Encinas, Miguel A Miranda, Nadia Chouinilalanne
    Abstract:

    The photophysical properties and photochemistry of Indoprofen (INP) have been investigated. Absorption and emission spectroscopies in phosphate buffer, ethanol and ether show that INP photophysics is dominated by a singlet-singlet transition of pipi* character. INP fluoresces at room temperature, with a quantum yield approximately 0.04. Flash photolysis experiments together with the lack of phosphorescence at room temperature point to a very weak intersystem crossing. The photoreactivity of INP is centered on the propionic acid chain and gives rise to photoproducts similar to those obtained with other arylpropionic acids (ethyl, hydroxyethyl and acetyl derivatives). Thus, irradiation of INP in aqueous buffer results in photodecarboxylation and leads mainly to oxidative compounds whose proportions increase with increasing oxygen concentration. These data suggest a photoreactivity occurring from the excited singlet state.

M J Martin - One of the best experts on this subject based on the ideXlab platform.

M Srinivasan - One of the best experts on this subject based on the ideXlab platform.

  • computer simulation of the interaction of non steroidal anti inflammatory drugs Indoprofen and ns398 with cyclooxygenase
    Journal of Biomolecular Structure & Dynamics, 1999
    Co-Authors: V Kothekar, Shakti Sahi, M Srinivasan
    Abstract:

    We have applied computer simulation technique to study interaction of two anti-inflammatory drugs (NSAIDs) Indoprofen and NS398 with cyclooxygenase (COX-1 and COX-2) enzymes. We have also investigated conformational flexibility of the two drugs by systematic search and simulated annealing molecular dynamics (SAMD) methods. Both the drugs were docked in the cyclooxygenase channel using in house docking program IMF1. The complexes were energy minimised by molecular mechanics (MM) method. These were heated for 30 picoseconds (ps), equilibrated for 110 ps at 300K and subjected to 'production simulation' for 110 ps by molecular dynamics (MD) method using Sanderis module of AMBER 5.0 package and united atom force field mostly from PARM96.DAT. Integration was carried out with time step of 0.001 ps, distance dependent di-electric constant with scaling factor 2.0 for 1-4 interaction and cut-off distance for non-bonded pair-list equal to 8A. The non-bonded pair-list was upgraded after every 20 cycles. The coordinate output from MD trajectories is analysed using analysis package of AMBER 5.0, MOLMOL, P-CURVES 3.0 and in house packages: ANALMD, ANALP1. We have observed perturbative changes in COX-1 and COX-2 structures due to Indoprofen and NS398. In case of Indoprofen specific changes between COX-1 and COX-2 were noted in helix D, H6, S6 and helix H8 in the cyclooxygenase cavity. In case of NS398 these were in helix B in membrane binding domain, helix H6, S8 and S10 in cyclooxygenase cavity and helices H14-H16 in small lobe close to haem binding region. Implications of these results in enzyme selectivity by NSAIDs is discussed here.