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Small photo-activatable molecules to control biological processes with light
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Substances naturelles et d'inspiration naturelle: de la synthèse totale à la chimie médicinale
No full textNational audienceFaut-il rappeler que la synthèse totale permet de préparer des composés d'intérêt ? Les substances naturelles sont les cibles habituelles de la synthèse totale, posant souvent des défis stratégiques pour atteindre une complexité moléculaire biologiquement fonctionnelle.[1] Non seulement elle permet d'accéder à des composés souvent difficilement accessibles en vue d'études biologiques — parfois au profit de la préservation d'une espèce rare ou difficilement accessible — mais elle permet également de mettre au point de nouvelles méthodes de synthèse pour accéder à des motifs singuliers.Notre but est de réaliser des synthèses totales non seulement associées à des développements méthodologiques, mais aussi avec des perspectives d'application biologiques ciblées.[2] Les méthodologies d'intérêt incluent la génération rapide de la complexité et de la diversité : stratégies bio-inspirées, fonctionnalisation tardive dans un contexte médicinal, cycloadditions ou réactions en cascade.[3] Des applications en chimie médicinale, en chémobiologie, ou encore en agronomie découlent naturellement de ces travaux. Cette conférence sera l'occasion de montrer quelques-unes de nos réalisations en synthèse totale de cytochalasines[3b,3d] ou de produits naturels à cycle oxépine,[3a] et les applications que nous en faisons en biologie
A Convergent Approach to 1,3-Dithiolan-2-ones and an Unexpected Synthesis of Lactones
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Mixed Ionic Liquids as Entrainers for Aromatic Extraction Processes: Energy, Economic, and Environmental Evaluations
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Ultra‐Fast Continuous‐Flow Photo‐Thiol‐Ene Functionalization of Conformation‐Controlled Cinchona Alkaloids
No full textInternational audienceIn this work, we describe ultra-fast continuous flow photo-thiolene reactions on cinchona alkaloids derivatives through a control of the reactive conformation in solution. Flow thiol-ene reactions proceed at 32 °C under light irradiation at 365 nm and require only 2.5 minutes of residence time to reach completion. The short path length of the tubular flow photochemical reactor, which maximizes and homogenizes the photon flux, associated to the fine tuning of the reactive conformation of cinchona alkaloids in solution are the main reasons for the high rates observed. The predominant conformation in solution of cinchona alkaloids was adjusted through the substitution of the hydroxyl group at C9 by a phenyl carbamate function
Relaxed-inertial proximal point algorithms for problems involving strongly quasiconvex functions
No full textInternational audienceIntroduced in the 1970's by Martinet for minimizing convex functions and extended shortly afterward by Rockafellar towards monotone inclusion problems, the proximal point algorithm turned out to be a viable computational method for solving various classes of optimization problems, in particular with nonconvex objective functions.We propose first a relaxed-inertial proximal point type algorithm for solving optimization problems consisting in minimizing strongly quasiconvex functions whose variables lie in finitely dimensional linear subspaces. The method is then extended to equilibrium problems where the involved bifunction is strongly quasiconvex in the second variable.Possible modifications of the hypotheses that would allow the algorithms to solve similar problems involving quasiconvex functions are discussed, too. Numerical experiments confirming the theoretical results, in particular that the relaxed-inertial algorithms outperform their ``pure'' proximal point counterparts, are provided, too
Stochastic calculus via regularizations
No full textInternational audienceA self-contained contribution to stochastic analysis mixing probability functional analysis and pathwise techniquesA comprehensive book starting from elementary concepts in probabilityFormulates the state of the art of stochastic calculus beyond semimartingale
Design, synthesis and cholinesterase inhibitory activity of new dispiro pyrrolidine derivatives
No full textInternational audienceA series of new dispiro pyrrolidines were regioselectively synthesised via [3+2]cycloaddition reactions of 3,5-bis(arylidene)-1-phenylethyl-4-piperidones with azomethine ylides generated in situ from N-methylglycine and appropriate isatin derivatives. The structures of the synthesised compounds were characterised by NMR, FT-IR and MS. These compounds were assayed in vitro for their inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), using Ellman's assay. The results demonstrate better inhibitory activity against butyrylcholinesterase as compared to acetylcholinesterase. Compound 7b exhibits potential as a new BChE inhibitor, with an IC50 of 12.78 ± 1.52 μM. A kinetic study suggests 7b as a mixed-mode inhibitor, where the active molecule can bind to the active or allosteric sites of the enzyme. An in silico study was performed using AutoDock Vina to identify the binding energy and conformation of 7b with the crystal structure of BChE complexed with Thioflavin T (PDB ID: 6ESY) and the crystal structure of human AChE complexed with dihydrotanshinone 1 (PDB ID: 4M0E). The results indicate better binding properties of 7b compared with the standard inhibitor Thioflavin T, with calculated binding energies of-13.9 and-9.7 kcal mol-1 for BChE and AChE, respectively
Titanium-mediated expedient synthesis of complex nitrogen heterocycles
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