Multistep reactions based on thiolactones for the synthesis of functionalized polymers

The aim of this research project was to develop a method for the synthesis of advanced polymeric structures without the use of timeconsuming protecting group strategies. The proposed method is based on the reaction between thiols and unsaturated carbon chains, denoted as thiol-ene or thiol-yne chemistry. Because of the disadvantages of working with thiols (i.e. unpleasant smell, limited commercial availability and instability due to oxidation reactions), there has been a continuous interest in the development of new ways to protect thiols, e.g. as disulfide, thiocarbonylthio-group or methanesulfonate. However, most of these methods require a protecting and a deprotecting step, which is unfavorable in terms of atom-efficiency and overall yield. The strategy herein presented, is based on the use of a thiolactone as a precursor for a thiol, allowing for the direct introduction of a thiol, starting from stable amino compounds without the need for a subsequent deprotection step. Using thiolactones in polymer synthesis has a dual advantage: On the one hand, it offers a chemoselective, atom-efficient way of generating thiols, while at the same time it is possible to introduce functionality via the amine compound. This one-pot amine-thiol-ene conjugation reaction was used for the synthesis and modification of diverse polymeric systems

One-pot, additive-free preparation of functionalized polyurethanes via amine-thiol-ene conjugation

A straightforward, isocyanate-free method for the synthesis of functionalized polyurethanes, based on amine-thiol-ene conjugation, was elaborated. Aminolysis of a readily available AB'-urethane monomer, containing both an acrylate (A) and a thiolactone unit (B'), facilitates the preparation of various reactive thiol-acrylates. In situ polymerization via Michael addition proceeds under ambient conditions, yielding polyurethanes with a large variety of chemical functionalities. Side-chain functionality originates from the modular use of different amines, allowing for the introduction of pendent functional groups (e.g. double bond, triple bond, furfuryl, tertiary amine, morpholine) along the polyurethane backbone. Extensive model studies revealed the kinetic profile of this reaction sequence and excluded the occurrence of competing reactions, such as aza-Michael addition and disulfide formation. This mild one-pot reaction requires no additives or external trigger and the obtained polyurethanes remain soluble throughout the process, enabling post-polymerization modification in the same reaction medium

Les festivals et autres événements culturels

La multiplication des événements culturels depuis une trentaine d’années modifie profondément le paysage culturel en Communauté française. Qu’ils soient ponctuels ou récurrents, les événements culturels jouent dorénavant, et au même titre que les institutions culturelles permanentes, un rôle important pour l’accès à la culture. Mais qu’impliquent ces événements ?Peut-on réellement parler de festivalisation ?Qui participe à leur organisation ?Ce Dossier tente de répondre à ces questions. La première partie livre une analyse théorique puis historique de l’événementiel culturel, avant de dresser un panorama original des festivals culturels en Wallonie et à Bruxelles. L’étude de 275 festivals permet de dégager les principales caractéristiques de ce type de manifestations (localisation, durée, ancienneté, affluence…).La deuxième partie porte sur les acteurs de l’événementiel culturel :organisateurs, pouvoirs publics, artistes, public et partenaires (sponsors, médias, associations, sous-traitants spécialisés) qui, chacun pour ses propres raisons (intellectuelles, politiques, économiques…), trouvent un intérêt à l’existence et à la tenue d’événements culturels.info:eu-repo/semantics/publishe

Actionnariat des entreprises wallonnes

Ce site est la partie visible de la base de données sur l'actionnariat des entreprises wallonnes qu'entretient le CRISP depuis plusieurs dizaines d'années. Il répertorie toutes les entreprises commerciales présentes en Wallonie. Pour chaque entreprise, il met à disposition du public des données d'identification (n° de tva, adresse, forme juridique, etc.), des données financières, ainsi que les informations disponibles sur leur actionnariat.L’originalité des informations collectées par le CRISP consiste à faire apparaître l’appartenance des entreprises aux groupes d’entreprises et donc d'identifier les centres de décision effectifs qui contrôlent ces entreprises.info:eu-repo/semantics/nonPublishe

One-pot multistep reactions based on thiolactones: extending the realm of thiol-ene chemistry in polymer synthesis

The in situ generation of thiols by nucleophilic ring-opening of a thiolactone with amines, followed by a UV-initiated radical thiol-ene reaction in a one-pot fashion, has been evaluated as an accelerated and versatile protocol for the synthesis of several types of polymeric architectures. After elaboration of a model amine-thiol-ene conjugation reaction, a number of routes based on readily available thiolactone-containing structures have been developed to successfully assemble functional, linear polymers and networks via a mild and facile radical photopolymerization process