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Start Over Author "Gérard Audran" Publisher american chemical society
5 results on '"Gérard Audran"'

3. Shifting-Nitroxides to Investigate Enzymatic Hydrolysis of Fatty Acids by Lipases Using Electron Paramagnetic Resonance in Turbid Media

Author

Philippe Mellet, Sylvain R. A. Marque, Natacha Jugniot, Samuel Jacoutot, Gérard Audran, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre de résonance magnétique des systèmes biologiques (CRMSB), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)

Subjects
[SDV]Life Sciences [q-bio], 010402 general chemistry, 01 natural sciences, Analytical Chemistry, law.invention, Hydrolysis, chemistry.chemical_compound, law, Enzymatic hydrolysis, Animals, Organic chemistry, Lipase, Solubility, Electron paramagnetic resonance, Candida, Aqueous solution, biology, Chemistry, Fatty Acids, 010401 analytical chemistry, Electron Spin Resonance Spectroscopy, Enol, 0104 chemical sciences, Candida rugosa, biology.protein, Nitrogen Oxides
Abstract

International audience; While optical methods are not efficient enough for the easy, fast, and efficient detection of enzymatic activity in turbid media, the properties of the electron paramagnetic resonance (EPR) technique make it suitable for use in such media. Nitroxides which exhibit a change in their EPR hyperfine coupling constants upon enzymatic activity and are selective to lipases were developed under the name of shifting-nitroxides. Several fatty acids, exhibiting saturated and unsaturated chains of various lengths, were coupled with the shifting-nitroxide via an enol ester link and tested against several lipases. As the solubility of fatty acids is low in HEPES buffer, experiments were performed in turbid aqueous solution. Almost all labeled fatty acids were hydrolyzed by Candida rugosa lipase, and more selectivity is observed with Porcine Pancreas lipase type II. No activity was observed for lipase AK Amano 20, Candida antartica lipase B, and Mucor miehei lipase.

Published
2019
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4. Total Synthesis of (+)-Crocacin C Using Hidden Symmetry.

Author

Candy, Mathieu, Gérard Audran, Bienaymé, Hugues, Bressy, Cyril, and Pons, Jean-Marc

Subjects
*ENANTIOSELECTIVE catalysis, *ORGANIC synthesis, *ASYMMETRIC synthesis, *ENZYMES, *RING-opening polymerization, *CATALYSIS, *POLYMERIZATION
Abstract

A highly convergent and protecting-group-free synthesis of (+)-crocacin C, featuring an enzymatic enantioselective desymmetrization of a meso-diol, a base-induced ring opening of a THP ring, and a one-pot hydrostannylation/Stille coupling as the key steps, is reported. The natural product was obtained in 11 steps and 22.3% overall yield starting from readily available oxabicycle 1. Finally, a unique enantioselective step, an enzymatic desymmetrization, revealed four stereogenic centers and created one in C4 of the THP furnishing the dense building block 4 with high enantioselectivity (ee >98%). [ABSTRACT FROM AUTHOR]

Published
2010
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5. Enantioselective Enzymatic Desymmetrization of Highly Functionalized MesoTetrahydropyranyl Diols†.

Author

Mathieu Candy, Gérard Audran, Hugues Bienaymé, Cyril Bressy, and Jean-Marc Pons

Subjects
*PYRAN, *ENZYMES, *ENANTIOMERS, *HETEROCYCLIC compounds, *ORGANIC compounds
Abstract

The enantioselective enzymatic desymmetrization of several highly substituted meso-tetrahydropyranyl diols is described. This transformation leads to valuable building blocks containing up to five stereogenic centers, which are revealed in a single step with both high yields and excellent enantiomeric excesses. Moreover, it was shown that this kind of building blocks could provide an easy access to both enantiomers of highly functionalized stereotetrads. [ABSTRACT FROM AUTHOR]

Published
2009
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