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7 results on '"Jeffrey Havot"'

1. Alkoxyamines Designed as Potential Drugs against Plasmodium and Schistosoma Parasites

Author

Thibaud Reyser, Tung H. To, Chinedu Egwu, Lucie Paloque, Michel Nguyen, Alexandre Hamouy, Jean-Luc Stigliani, Christian Bijani, Jean-Michel Augereau, Jean-Patrick Joly, Julien Portela, Jeffrey Havot, Sylvain R. A. Marque, Jérôme Boissier, Anne Robert, Françoise Benoit-Vical, and Gérard Audran

Subjects
alkoxyamine, alkylation, heme, malaria, radical chemistry, schistosomiasis, Organic chemistry, QD241-441
Abstract

Malaria and schistosomiasis are major infectious causes of morbidity and mortality in the tropical and sub-tropical areas. Due to the widespread drug resistance of the parasites, the availability of new efficient and affordable drugs for these endemic pathologies is now a critical public health issue. In this study, we report the design, the synthesis and the preliminary biological evaluation of a series of alkoxyamine derivatives as potential drugs against Plasmodium and Schistosoma parasites. The compounds (RS/SR)-2F, (RR/SS)-2F, and 8F, having IC50 values in nanomolar range against drug-resistant P. falciparum strains, but also five other alkoxyamines, inducing the death of all adult worms of S. mansoni in only 1 h, can be considered as interesting chemical starting points of the series for improvement of the activity, and further structure activity, relationship studies. Moreover, investigation of the mode of action and the rate constants kd for C-ON bond homolysis of new alkoxyamines is reported, showing a possible alkyl radical mediated biological activity. A theoretical chemistry study allowed us to design new structures of alkoxyamines in order to improve the selectivity index of these drugs.

Published
2020
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2. Uncovering the Role of Chemical and Electronic Structures in Plasmonic Catalysis: The Case of Homolysis of Alkoxyamines

Author

Darya Votkina, Pavel Petunin, Elena Miliutina, Andrii Trelin, Oleksiy Lyutakov, Vaclav Svorcik, Gérard Audran, Jeffrey Havot, Rashid Valiev, Lenara I. Valiulina, Jean-Patrick Joly, Yusuke Yamauchi, Junais Habeeb Mokkath, Joel Henzie, Olga Guselnikova, Sylvain R. A. Marque, and Pavel Postnikov

Subjects
General Chemistry, Catalysis
Published
2023
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3. Cascade strategy for triggered radical release by magnetic nanoparticles grafted with thermosensitive alkoxyamine

Author

Basile Bouvet, Saad Sene, Gautier Félix, Jeffrey Havot, Gerard Audran, Sylvain R. A. Marque, Joulia Larionova, and Yannick Guari

Subjects
General Materials Science
Abstract

The design of smart nanoplatforms presenting well-definite structures able to achieve controlled cascade action remotely triggered by external stimuli presents a great challenge. We report here a new nanosystem consisting of magnetic iron oxide nanoparticles covalently grafted with a thermosensitive radical initiator alkoxyamine, able to provide controlled and localized release of free radicals triggered by an alternating current (ac) magnetic field. These nanoparticles exhibit a high intrinsic loss power of 4.73 nHm

Published
2023
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4. Homolysis/mesolysis of alkoxyamines activated by chemical oxidation and photochemical-triggered radical reactions at room temperature

Author

Sylvain R. A. Marque, Micael Hardy, Michelle L. Coote, Dmytro Neshchadin, Mitchell T. Blyth, Gérard Audran, Georg Gescheidt, Tataye Moussounda Moussounda Koumba, Maxence Holzritter, Jean-Patrick Joly, Jeffrey Havot, Enzo Vaiedelich, Samuel Jacoutot, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Research School of Chemistry, Australian National UniversityCanberra ACT 2601 Australia, and Institute of Physical and Theoretical Chemistry, TU GrazStremayrgasse 9/Z2 A-8010 Graz Austria

Subjects
Nitroxide mediated radical polymerization, 010405 organic chemistry, Organic Chemistry, Lead dioxide, Methylene bridge, 010402 general chemistry, Photochemistry, 01 natural sciences, 0104 chemical sciences, Catalysis, Homolysis, Solvent, chemistry.chemical_compound, chemistry, Moiety, [CHIM]Chemical Sciences, Bond cleavage
Abstract

Alkoxyamines, which are connected with a phenol moiety by a (substituted) methylene bridge undergo homolytic cleavage upon chemical oxidation or a photo-induced hydrogen transfer. This selectively triggered reaction yields a nitroxide radical. In the presence of an excess of lead dioxide as the oxidant in tert-butylbenzene as solvent, spontaneous, instantaneous and almost quantitative generations of nitroxides from various alkoxyamines are observed at room temperature, which support activation energies for the cleavage lower than 100 kJ mol−1. The rate and the amount of released nitroxide depend on the amount of “catalyst” and the structure of alkoxyamines.

Published
2021
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5. Unveiling the role of chemical and electronic structure in plasmon-assisted homolysis of alkoxyamines

Author

Elena Miliutina, Pavel S. Postnikov, Olga Guselnikova, Rashid R. Valiev, Václav Švorčík, Oleksiy Lyutakov, Sylvain R. A. Marque, Gérard Audran, Darya E. Votkina, Jean-Patrick Joly, Lenara I. Valiulina, Jeffrey Havot, Andrii Trelin, and Pavel V. Petunin

Subjects
Reaction rate constant, Chemistry, law, Intramolecular force, Electronic structure, Surface plasmon resonance, Photochemistry, Electron paramagnetic resonance, Chemical reaction, Plasmon, Homolysis, law.invention
Abstract

The excitation of localized plasmon resonance on nanoparticles followed by the interaction with organic molecules leads to new pathways of chemical reactions. Although a number of physical factors (temperature, illumination regime, type of nanoparticles, etc.) are affecting this process, the role of the chemical factors is underestimated. Challenging this assumption, here we studied the kinetic of plasmon-induced homolysis of five alkoxyamines (AAs) with different chemical and electronic structures using electron paramagnetic resonance (EPR). The kinetic data revealed the dependence of plasmonic homolysis rate constant (kd) with the HOMO energy of AAs, which cannot be described by the kinetic parameters derived from thermal homolysis experiments. The observed trend in kd allowed to suggest the key role of intramolecular excitation mechanism supported by the TDFDT calculations, additional spectroscopic characterization, and control experiments. Our work sheds light on the role of the electronic structure of organic molecules in plasmonic chemistry.

Published
2021
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6. Unveiling the role of chemical and electronic structure in plasmon-assisted homolysis of alkoxyamines

Author

Darya Votkina, Pavel Petunin, Elena Miliutina, Andrii Trelin, Oleksiy Lyutakov, Vaclav Svorcik, Gérard Audran, Jeffrey Havot, Rashid Valiev, Lenara Valiulina, Jean-Patrick Joly, Olga Guselnikova, Sylvain Marque, and Pavel Postnikov

Abstract

The excitation of localized plasmon resonance on nanoparticles followed by the interaction with organic molecules leads to new pathways of chemical reactions. Although a number of physical factors (temperature, illumination regime, type of nanoparticles, etc.) are affecting this process, the role of the chemical factors is underestimated. Challenging this assumption, here we studied the kinetic of plasmon-induced homolysis of five alkoxyamines (AAs) with different chemical and electronic structures using electron paramagnetic resonance (EPR). The kinetic data revealed the dependence of plasmonic homolysis rate constant (kd) with the HOMO energy of AAs, which cannot be described by the kinetic parameters derived from thermal homolysis experiments. The observed trend in kd allowed to suggest the key role of intramolecular excitation mechanism supported by the TDFDT calculations, additional spectroscopic characterization, and control experiments. Our work sheds light on the role of the electronic structure of organic molecules in plasmonic chemistry.

Published
2021
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7. Alkoxyamines Designed as Potential Drugs against Plasmodium and Schistosoma Parasites

Author

Chinedu O. Egwu, Thibaud Reyser, Jean-Luc Stigliani, Gérard Audran, Tung H To, Christian Bijani, Sylvain R. A. Marque, Françoise Benoit-Vical, Alexandre Hamouy, Jeffrey Havot, Michel Nguyen, Jérôme Boissier, Anne Robert, Lucie Paloque, Jean-Michel Augereau, Jean-Patrick Joly, Julien Portela, Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de pharmacologie et de biologie structurale (IPBS), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), S.A.S ParaDev, Interactions Hôtes-Pathogènes-Environnements (IHPE), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Perpignan Via Domitia (UPVD), Institut National de la Santé et de la Recherche Médicale (INSERM), Gulli, Marie-Hélène, Stratégie thérapeutique par voie radicalaire pour combattre des maladies parasitaires - - RADICAL2017 - ANR-17-CE18-0017 - AAPG2017 - VALID, Institut de Chimie de Toulouse (ICT-FR 2599), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université de Perpignan Via Domitia (UPVD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Aix-Marseille Université, Université de Perpignan, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (Inserm), ANR-17-CE18-0017,RADICAL,Stratégie thérapeutique par voie radicalaire pour combattre des maladies parasitaires(2017), Institut de Chimie de Toulouse (ICT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Alkylation, [CHIM.THER] Chemical Sciences/Medicinal Chemistry, Plasmodium falciparum, malaria, Pharmaceutical Science, Schistosomiasis, Drug resistance, Heme, [CHIM.THER]Chemical Sciences/Medicinal Chemistry, Pharmacology, 010402 general chemistry, 01 natural sciences, Plasmodium, Article, Analytical Chemistry, lcsh:QD241-441, Antimalarials, lcsh:Organic chemistry, schistosomiasis, Drug Discovery, parasitic diseases, Ic50 values, medicine, Animals, Humans, radical chemistry, Physical and Theoretical Chemistry, heme, alkylation, Schistosoma, Biological evaluation, Anthelmintics, biology, 010405 organic chemistry, Organic Chemistry, Radical chemistry, Biological activity, Schistosoma mansoni, Alkoxyamine, biology.organism_classification, medicine.disease, 3. Good health, 0104 chemical sciences, Malaria, Chemistry (miscellaneous), Molecular Medicine, alkoxyamine
Abstract

Malaria and schistosomiasis are major infectious causes of morbidity and mortality in the tropical and sub-tropical areas. Due to the widespread drug resistance of the parasites, the availability of new efficient and affordable drugs for these endemic pathologies is now a critical public health issue. In this study, we report the design, the synthesis and the preliminary biological evaluation of a series of alkoxyamine derivatives as potential drugs against Plasmodium and Schistosoma parasites. The compounds (RS/SR)-2F, (RR/SS)-2F, and 8F, having IC50 values in nanomolar range against drug-resistant P. falciparum strains, but also five other alkoxyamines, inducing the death of all adult worms of S. mansoni in only 1 h, can be considered as interesting chemical starting points of the series for improvement of the activity, and further structure activity, relationship studies. Moreover, investigation of the mode of action and the rate constants kd for C-ON bond homolysis of new alkoxyamines is reported, showing a possible alkyl radical mediated biological activity. A theoretical chemistry study allowed us to design new structures of alkoxyamines in order to improve the selectivity index of these drugs.

Published
2020
Full Text
View/download PDF

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