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7 results on '"Stéphanie Castex"'

1. Green synthesis of (R)-3-hydroxy-decanoic acid and analogs from levoglucosenone: a novel access to the fatty acid moiety of rhamnolipids

Author

Enzo Petracco, Amandine L. Flourat, Marie-Charlotte Belhomme, Stéphanie Castex, Fanny Brunissen, Fanny Brunois, Aurélien A. M. Peru, Florent Allais, and Arnaud Haudrechy

Subjects
crop protection agent, cross-coupling, green chemistry, levoglucosenone, Michael addition, Chemistry, QD1-999
Abstract

Rhamnolipids (RLs) are highly valuable molecules in the cosmetic, pharmaceutic, and agricultural sectors with outstanding biosurfactant properties. In agriculture, due to their potential to artificially stimulate the natural immune system of crops (also known as elicitation), they could represent a critical substitute to conventional pesticides. However, their current synthesis methods are complex and not aligned with green chemistry principles, posing a challenge for their industrial applications. In addition, their bioproduction is cumbersome with reproducibility issues and expensive downstream processing. This work offers a more straightforward and green access to RLs, crucial to decipher their mechanisms of action and design novel potent and eco-friendly elicitors. To achieve this, we propose an efficient seven-step synthetic pathway toward (R)-3-hydroxyfatty acid chains present in RLs, starting from cellulose-derived levoglucosenone, with Michael addition, Baeyer–Villiger oxidation, Bernet–Vasella reaction, and cross-metathesis homologation as key steps. This method allowed the production of (R)-3-hydroxyfatty acid chains and derivatives with an overall yield ranging from 24% to 36%.

Published
2024
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2. A stereo-electronic interpretation of a challenging orthoamide Overman rearrangement rationalized by molecular modelling

Author

Judith Juvin, Victor Malherbe, Marie-Charlotte Belhomme, Stéphanie Castex, Agathe Martinez, Hassan Khartabil, and Arnaud Haudrechy

Subjects
Materials Chemistry, General Chemistry, Catalysis
Abstract

The Overman rearrangement difficulties are tentatively explained using stereo-electronic considerations, helping chemists to understand their troubles in this process.

Published
2022

3. Un bon croquis vaut mieux qu’un long discours ? / A good sketch is better than a long speech?

Author

Judith Juvin, Marie-Charlotte Belhomme, Stéphanie Castex, Christophe Bliard, and Arnaud Haudrechy

Abstract

Napoleon Bonaparte once said, “A good sketch is better than a long speech”. Though an ardent promoter of beet sugar production, Napoleon could never have imagined that he was describing the thorny problem of the stereochemical representation of sugars. Drawing the structure of a sugar molecule (also called “carbohydrate”) means addressing the challenge of unambiguously transcribing a three-dimensional reality into a bi-dimensional representation as accurately as possible. Since Emil Fischer's initial proposals, several methods have been suggested, with their advantages and drawbacks. Consequently, selecting a particular approach is far from inconsequential and involves numerous pitfalls. The objective of this document is to raise awareness of the subtleties of sugar molecules representations.

Published
2021

4. Sugars: Intramolecular Dehydration of Hexoses

Author

Marie-Charlotte Belhomme, Arnaud Haudrechy, and Stéphanie Castex

Subjects
Chemistry, Intramolecular force, medicine, Dehydration, medicine.disease, Medicinal chemistry
Published
2021

5. Un bon croquis vaut mieux qu’un long discours ?

Author

Judith Juvin, Marie-Charlotte Belhomme, Stéphanie Castex, Christophe Bliard, Arnaud Haudrechy, bliard, christophe, Institut de Chimie Moléculaire de Reims - UMR 7312 (ICMR), SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-SFR CAP Santé (Champagne-Ardenne Picardie Santé), and Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
dessins, tridimensional, [CHIM.ORGA]Chemical Sciences/Organic chemistry, [CHIM.OTHE] Chemical Sciences/Other, tridimensionnel sugars, [CHIM.OTHE]Chemical Sciences/Other, sucres, [CHIM.ORGA] Chemical Sciences/Organic chemistry, drawings
Abstract

Napoleon Bonaparte once said, “A good sketch is better than a long speech”. Though an ardent promoter of beet sugar production, Napoleon could never have imagined that he was describing the thorny problem of the stereo- chemical representation of sugars. Drawing the structure of a sugar molecule (also called “carbohydrate”) means addressing the challenge of unambiguously transcribing a three-dimensional reality into a bi-dimensional representation as accurately as possible. Since Emil Fischer's initial proposals, several methods have been suggested, with their advantages and drawbacks. Consequently, selecting a particular approach is far from inconsequential and involves numerous pitfalls. The objective of this document is to raise awareness of the subtleties of sugar molecules representations., En disant « Un bon croquis vaut mieux qu'un long discours », Napoléon Bonaparte, pourtant promoteur de la production de sucre de betterave, n'imaginait sans doute pas contribuer au débat sur la représentation stéréochimique des sucres. Dessiner la structure d'une molécule de sucre (en anglais, la terminologie anachronique « hydrate de carbone » subsiste parfois) impose de transcrire, le plus fidèlement possible et sans ambiguïté, une correspondance entre une réalité tridimensionnelle et une représentation bidimensionnelle. Depuis les propositions initiales d'Emil Fischer, plusieurs méthodes ont été présentées. Cet article vise à faire prendre conscience de la subtilité des représentations isomériques des molécules de sucres.

Published
2021

6. 'Sugar Mapping', an Easy-To-Use Visual Tool To Help the Synthetic Chemist Identify Carbohydrate Stereochemical Relationships

Author

Stéphanie Castex, Arnaud Haudrechy, Marie Charlotte Belhomme, Institut de Chimie Moléculaire de Reims - UMR 7312 (ICMR), SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-SFR CAP Santé (Champagne-Ardenne Picardie Santé), and Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, Science instruction, 010405 organic chemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, 05 social sciences, 050301 education, Pentose, General Chemistry, Carbohydrate, Chemist, 01 natural sciences, 0104 chemical sciences, 3. Good health, Education, chemistry, Organic chemistry, Sugar, 0503 education, Visual tool, ComputingMilieux_MISCELLANEOUS
Abstract

A “map” is presented to describe the different stereochemical relationships among carbohydrates, in both the hexose and pentose series. When implemented, it allows chemistry students, teachers, and researchers to readily identify different sugars’ stereochemical interconnections. It may also help orient chemists toward retrosyntheses, in which carbohydrates are used as starting material goals.

Published
2019

7. Small Molecule Mixture Analysis by Heteronuclear NMR under Spin Diffusion Conditions in Viscous DMSO-Water Solvent

Author

Jean-Marc Nuzillard, Pedro Lameiras, Jouda Jakhlal, Pascale Clivio, Solène Patis, Stéphanie Castex, Institut de Chimie Moléculaire de Reims - UMR 7312 ( ICMR ), SFR Condorcet, Université de Reims Champagne-Ardenne ( URCA ) -Université de Picardie Jules Verne ( UPJV ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Reims Champagne-Ardenne ( URCA ) -Université de Picardie Jules Verne ( UPJV ) -Centre National de la Recherche Scientifique ( CNRS ) -SFR CAP Santé (Champagne-Ardenne Picardie Santé), Université de Reims Champagne-Ardenne ( URCA ) -Université de Picardie Jules Verne ( UPJV ) -Université de Reims Champagne-Ardenne ( URCA ) -Université de Picardie Jules Verne ( UPJV ) -Université de Reims Champagne-Ardenne ( URCA ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Chimie Moléculaire de Reims - UMR 7312 (ICMR), Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-SFR CAP Santé (Champagne-Ardenne Picardie Santé), Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-SFR CAP Santé (Champagne-Ardenne Picardie Santé), Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-SFR Condorcet, and Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.ORGA]Chemical Sciences/Organic chemistry, 010405 organic chemistry, Chemistry, Organic Chemistry, Analytical chemistry, General Chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Solvent, NMR spectra database, Magnetization, Heteronuclear molecule, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, [ CHIM.ORGA ] Chemical Sciences/Organic chemistry, Spin diffusion, Molecule, [ CHIM.ANAL ] Chemical Sciences/Analytical chemistry, Dissolution, Two-dimensional nuclear magnetic resonance spectroscopy, ComputingMilieux_MISCELLANEOUS
Abstract

International audience; Spin diffusion in NMR occurs for small‐ and medium‐sized molecules when their tumbling rate reduces in solution so that magnetization exchange by longitudinal cross relaxation becomes highly efficient. Composite DMSO–water viscous solvents were used for the first time to access the individual NMR spectra of a mixture components in spin diffusion conditions. The easy handling and high dissolution power of [D6]DMSO/H2O offers a wide range of potential applications for polar and moderately apolar mixture analysis. In addition to 2D 1H‐1H NOESY and 1H‐13C HSQC‐NOESY, 1H‐15N HSQC‐NOESY, 1D and 2D 1H‐19F heteronuclear NOESY (HOESY) experiments were set up to offer new ways to individualize molecules within a mixture. This article reports the analysis of a polar mixture of four dipeptides dissolved in [D6]DMSO/H2O (7:3 v/v) and that of a medium‐polarity fluorinated dinucleotide dissolved in [D6]DMSO/H2O (8:2 v/v) by means of spin diffusion in NOESY, HOESY, and HSQC–NOESY experiments.

Published
2017

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