20 research outputs found

    Di-tert-butyl 2-benzoyl­hydrazine-1,1-dicarboxyl­ate

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    The crystal structure of the title compound, C17H24N2O5, was determined in the course of our studies on the preparation of two families of pseudopeptides, viz. hydrazino- and N-amino- peptides. The most significant inter­action in the crystal structure is a bifurcated inter­molecular N—H⋯O hydrogen bond

    Enzyme-catalyzed mechanism of isoniazid activation in class I and class III peroxidases.

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    There is an urgent need to understand the mechanism of activation of the frontline anti-tuberculosis drug isoniazid by the Mycobacterium tuberculosis catalase-peroxidase. To address this, a combination of NMR spectroscopic, biochemical, and computational methods have been used to obtain a model of the frontline anti-tuberculosis drug isoniazid bound to the active site of the class III peroxidase, horseradish peroxidase C. This information has been used in combination with the new crystal structure of the M. tuberculosis catalase-peroxidase to predict the mode of INH binding across the class I heme peroxidase family. An enzyme-catalyzed mechanism for INH activation is proposed that brings together structural, functional, and spectroscopic data from a variety of sources. Collectively, the information not only provides a molecular basis for understanding INH activation by the M. tuberculosis catalase-peroxidase but also establishes a new conceptual framework for testing hypotheses regarding the enzyme-catalyzed turnover of this compound in a number of heme peroxidases

    Synthese de nouveaux complexes arynezirconocenes. Applications en syntheses organique et organometallique

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    SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 80271 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

    Cyclohexamer [-( D -Phe-azaPhe-Ala) 2 -]: good candidate to formulate supramolecular organogels

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    International audienceMolecular self-assembly is a fascinating process which has become an area of great interest insupramolecular chemistry, as it leads in certain cases to molecular gels. Organogels formulated from lowmolecular weight compounds (LMWOGs) have attracted much interest in the past decades due to theirapplications as new soft materials. Herein, we report on the ability of the cyclic pseudopeptide cyclo-[-(D-Phe-azaPhe-Ala)2-] (2) to self-assemble in some aromatic solvents and to form organogels drivenby non-covalent forces, mainly hydrogen bonding and p-stacking interactions. Comprehensive FTIR andNMR studies emphasized that this cyclic aza-peptide adopts a b-turn conformation at low concentrationin toluene, while an equilibrium between the monomeric states (intramolecular forces) and thesupramolecular structures (intra- and intermolecular forces) is established at high concentration (gelstate). Rheological investigations of the organogels highlight the dependence of their stiffness (up to 4kPa) and sol/gel transition temperatures (up to 100 C) as a function of the solvent and concentration ofgelator used. The formulation of fibrous structures confirmed the phenomenon of self-assembly. Finally,we found that cyclo-[-(D-Phe-azaPhe-Ala)2-] is an effective organogelator for application in phaseselective gelation (PSG) of organic solvents from aqueous/organic mixtures with recovery percents up to96%
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