Agro-ressources et photo-régulation (vers la synthèse de nouveaux chromophores appliquée au domaine du développement durable)

De nos jours, il existe une forte demande pour que le secteur de la chimie devienne plus éco-compatible. L un des enjeux majeurs de la chimie verte est de remplacer, dans les réactions organiques, les solvants qui sont généralement très toxiques par des solvants moins nocifs comme l eau. Néanmoins, la faible solubilité des composés organiques en milieu aqueux ne permet pas l obtention de bons rendements réactionnels. Afin de pallier ce problème, l ajout de tensioactifs au milieu réactionnel a été envisagé. Leur organisation sous forme d agrégats va permettre de solubiliser des composés organiques dans l eau. Les tensioactifs vont alors jouer le rôle de chimio-réacteurs. Cependant, il est parfois difficile d extraire les produits en fin de réaction, ce qui entraîne également une difficulté pour le recyclage du milieu réactionnel. Pour résoudre ce problème, nous avons envisagé de synthétiser un tensioactif comportant un chromophore de type azobenzène. En effet ces composés ont la propriété de s isomériser de façon réversible de leur forme trans à leur forme cis lorsqu ils sont irradiés à une longueur d onde spécifique. Nous avons mis au point la synthèse de l un de ces tensioactifs. Ces propriétés physico-chimiques de tensioactivité et de photo-régulation ont été par la suite mises en évidence. Son rôle de chimio-réacteur pour la synthèse organique a été évalué et son emploi permet d augmenter le rendement réactionnel. De plus, ses propriétés photochromiques permettent de faciliter l extraction des produits en fin de réaction ainsi que son recyclage.The field of chemistry has witnessed a huge development since the 20th century. Nowadays, this field really needs to become more eco-friendly. One of the major challenges in green chemistry is to replace organic solvents with less hazardous solvents such as water. However, organic compounds are not very soluble in water, which involves a poor yield of organic reactions. To solve this problem, the use of surfactants has been considered. Indeed, those products organized themselves to form micelles, which allows the solubilization of organic compounds and play the part of chimio-reactors. Nevertheless, it can be difficult to extract the products at the end of the reaction, which will make the recycling of the reactional media less efficient. The solution we consider is to synthesize a new surfactant containing an azobenzene as chromophore. Actually, those compounds have the properties to isomerize themselves from their trans forms to their cis forms. This process is reversible. One of these surfactants was synthesized. Its physico-chemicals properties of tensioactivity and photo-regulation have been proved. The use of this surfactant as chimio-reactor for the organic synthesis has been assessed. We were able to show that its employ allows the increase of the yield of the reaction. Moreover, its photochromism properties permit to make the extraction of the products- at the end of the reaction- and also the recycling easier.COMPIEGNE-BU (601592101) / SudocSudocFranceF

Synthesis and Evaluation of a Photochromic Surfactant for Organic Reactions in Aqueous Media

International audienc

Micellar Catalysis Using a Photochromic Surfactant: Application to the Pd-Catalyzed Tsuji–Trost Reaction in Water

International audienc

Synthesis and Evaluation of a Photochromic Surfactant for Organic Reactions in Aqueous Media

A novel photochromic azobenzene-based surfactant was described for organic chemistry in water. The molecule 4-butylazobenzyl-4′-triazologlucuronic acid sodium salt thus synthesized can be isomerized from its trans to its cis form reversibly in solution by simple light irradiation. That property allowed the recyclability of a model acetylation reaction performed in the surfactant media, compared to the well-known, commercially available sodium dodecyl sulfate surfactant media

Use of calcofluor-blue brightener for the diagnosis of Pneumocystis jirovecii pneumonia in bronchial-alveolar lavage fluids: A single-center prospective study

International audienceThe biological diagnosis of Pneumocystis jirovecii pneumonia (PjP) is based on the investigation of respiratory fluids by conventional staining methods and/or molecular biology. Diagnostic performance of an in-house technique based on calcofluor-blue brightener for the direct detection of P. jirovecii cysts was prospectively assessed in bronchial-alveolar lavage fluids (BALF) from patients with a suspected PjP infection over a three-year period in a single center: the diagnostic yield was compared to that of a commercial kit based on monoclonal immunofluorescence assay (IFA) on replicate smears. May-Grünwald Giemsa (MGG) staining and quantitative Polymerase Chain Reaction (qPCR) were also performed. The gold standard for each patient was the definitive diagnosis of PjP infection by an independent committee based on clinical, radiological, and biological data. Overall, 481 BALF were assessed: 42 were found to be positive for the detection of P. jirovecii by at least one laboratory technique, but only 35 were actually judged to be in agreement with the definitive diagnosis of PjP infection. The sensitivity of the calcofluor-blue brightener technique was 74.3% vs. 60.0%, 34.6%, and 82.9% for IFA, MGG, and qPCR, respectively; and its specificity was 99.6% vs. 99.3%, 100.0%, and 99.4% for IFA, MGG, and qPCR. No technique was shown to be statistically superior to calcofluor-blue brightener. Further validation of the test through multicenter studies is now required, but in light of its low cost and easy preparation, the use of calcofluor-blue brightener the use of calcofluor-blue brightener in BALF appears to be a valuable alternative method for the routine first-line diagnosis of PjP infection

Micellar Catalysis Using a Photochromic Surfactant: Application to the Pd-Catalyzed Tsuji–Trost Reaction in Water

The first example of a Pd-catalyzed Tsuji–Trost reaction, applied in a photochromic micellar media under conventional heating and microwave irradiation, is reported. The surfactant activity and recycling ability were investigated and compared with those of a few commercially available surfactants. The synthetic photochromic surfactant proved to be efficient, recyclable, and versatile for Pd-catalyzed coupling reactions

Biological, clinical features and modelling of heterozygous variants of glycoprotein Ib platelet subunit alpha (GP1BA) and glycoprotein Ib platelet subunit beta (GP1BB) genes responsible for constitutional thrombocytopenia

International audienceConstitutional thrombocytopenias are rare disorders, often difficult to discriminate from acquired thrombocytopenias. More than 80 genes have been described as being at the origin of these diseases. Among them, several variants of the glycoprotein Ib platelet subunit alpha (GP1BA) and glycoprotein Ib platelet subunit beta (GP1BB) genes, coding for the GpIb-IX-V glycoprotein complex, have been reported in the literature. The study reported here aimed at describing newly identified monoallelic anomalies affecting the GP1BA and GP1BB genes on a clinical, biological and molecular level. In a cohort of nine patients with macrothrombocytopenia, eight heterozygous variants of the GP1BA or GP1BB genes were identified. Five of them had never been described in the heterozygous state. Computer modelling disclosed structure/function relationships of these five variants

Management of rare inherited bleeding disorders: Proposals of the French Reference Centre on Haemophilia and Rare Coagulation Disorders

Introduction: The rare coagulation disorders may present significant difficulties in diagnosis and management. In addition, considerable inter-individual variation in bleeding phenotype is observed amongst affected individuals, making the bleeding risk difficult to assess in affected individuals. The last international recommendations on rare inherited bleeding disorders (RIBDs) were published by the United Kingdom Haemophilia Centre Doctors' Organisation in 2014. Since then, new drugs have been marketed, news studies on surgery management in patients with RIBD have been published, and new orphan diseases have been described. Aim: Therefore, the two main objectives of this review, based on the recent recommendations published by the French Reference Centre on Haemophilia and Rare Bleeding Disorders, are: (i) to briefly describe RIBD (clinical presentation and diagnostic work-up) to help physicians in patient screening for the early detection of such disorders; and (ii) to focus on the current management of acute haemorrhages and long term prophylaxis, surgical interventions, and pregnancy/delivery in patients with RIBD.</p