Palladium-catalysed direct regioselective C5-arylation of a thiophene bearing a cyclopropyl ketone group at C2

International audienceA thiophene bearing a cyclopropyl ketone group at C2 was successfully employed in palladium-catalysed direct arylation. The reaction proceeds regioselectively at C5 without decomposition of the cyclopropyl ketone substituent. These couplings were performed employing as little as 0.5 mol% of ligand-free Pd(OAc)2 catalyst with electron-deficient aryl bromides. A wide variety of functional groups on the aryl bromide such as nitrile, nitro, acetyl, formyl, benzoyl, ester, trifluoromethyl, fluoro or methoxy was tolerated. © 2013 Elsevier Science. All rights reserved

Development of a protocol for characterizing goniochromism

Les matériaux iridescents changent de couleur avec la géométrie d’éclairage et d’observation de l’objet. La croissance de leur utilisation dans des domaines comme la peinture automobile et la cosmétique fait du contrôle de leur apparence un enjeu. L’objectif de ce travail est de mettre en place un protocole de caractérisation qui permettrait d’évaluer les grandeurs caractéristiques de la perception du goniochromisme. Une caractérisation instrumentale et une autre sensorielle ont permis de recenser les attributs physiques et sensoriels qui caractérisent ces matériaux. Une confrontation des résultats de ces deux évaluations a été réalisée afin de chercher à exprimer les grandeurs sensorielles caractéristiques des matériaux goniochromes en fonction de grandeurs mesurables instrumentalement.Iridescent materials change their colour with the geometry of illumination and observation. The growth of their use in domains like automotive painting and cosmetics constitutes an important issue for appearance control. The aim of this work is to develop a protocol for evaluating the characteristics of goniochromism perception. Both instrumental and sensory measurements allowed us to determine the relevant physical and sensorial attributes characterising these materials. A confrontation of the results of both evaluations was carried out in order to express the sensory characteristics of the goniochromic materials according to instrumentally measurable quantities

Preparation and Characterization of a New Polymeric Multi-Layered Material Based K-Carrageenan and Alginate for Efficient Bio-Sorption of Methylene Blue Dye

The current study highlights a novel bio-sorbent design based on polyelectrolyte multi-layers (PEM) biopolymeric material. First layer was composed of sodium alginate and the second was constituted of citric acid and k-carrageenan. The PEM system was crosslinked to non-woven cellulosic textile material. Resulting materials were characterized using FT-IR, SEM, and thermal analysis (TGA and DTA). FT-IR analysis confirmed chemical interconnection of PEM bio-sorbent system. SEM features indicated that the microspaces between fibers were filled with layers of functionalizing polymers. PEM exhibited higher surface roughness compared to virgin sample. This modification of the surface morphology confirmed the stability and the effectiveness of the grafting method. Virgin cellulosic sample decomposed at 370 °C. However, PEM samples decomposed at 250 °C and 370 °C, which were attributed to the thermal decomposition of crosslinked sodium alginate and k-carrageenan and cellulose, respectively. The bio-sorbent performances were evaluated under different experimental conditions including pH, time, temperature, and initial dye concentration. The maximum adsorbed amounts of methylene blue are 124.4 mg/g and 522.4 mg/g for the untreated and grafted materials, respectively. The improvement in dye sorption evidenced the grafting of carboxylate and sulfonate groups onto cellulose surface. Adsorption process complied well with pseudo-first-order and Langmuir equations

A Simple and Efficient Synthesis of (Hetero)Aryl-Substituted Benzothiazolyl or Benzoxazolyl Furan, Thiophene and N-methylpyrrole Derivatives through a Palladium-Catalyzed Regioselective C–H Bond Arylation

International audienc

Preparation and Characterization of a New Polymeric Multi-Layered Material Based K-Carrageenan and Alginate for Efficient Bio-Sorption of Methylene Blue Dye

The current study highlights a novel bio-sorbent design based on polyelectrolyte multi-layers (PEM) biopolymeric material. First layer was composed of sodium alginate and the second was constituted of citric acid and k-carrageenan. The PEM system was crosslinked to non-woven cellulosic textile material. Resulting materials were characterized using FT-IR, SEM, and thermal analysis (TGA and DTA). FT-IR analysis confirmed chemical interconnection of PEM bio-sorbent system. SEM features indicated that the microspaces between fibers were filled with layers of functionalizing polymers. PEM exhibited higher surface roughness compared to virgin sample. This modification of the surface morphology confirmed the stability and the effectiveness of the grafting method. Virgin cellulosic sample decomposed at 370 °C. However, PEM samples decomposed at 250 °C and 370 °C, which were attributed to the thermal decomposition of crosslinked sodium alginate and k-carrageenan and cellulose, respectively. The bio-sorbent performances were evaluated under different experimental conditions including pH, time, temperature, and initial dye concentration. The maximum adsorbed amounts of methylene blue are 124.4 mg/g and 522.4 mg/g for the untreated and grafted materials, respectively. The improvement in dye sorption evidenced the grafting of carboxylate and sulfonate groups onto cellulose surface. Adsorption process complied well with pseudo-first-order and Langmuir equations

Reactivity of 3-(pyrrol-1-yl)thiophenes in Pd-catalysed direct arylations

International audienceThe regioselectivity of the Pd-catalysed direct arylation of 3-(pyrrol-1-yl)thiophene derivatives was investigated. Conditions allowing either the regioselective arylation at C2 or at C5 of the thiophene ring are reported. From methyl 3-(pyrrol-1-yl)thiophene-2-carboxylate using KOAc as the base, DMA as the solvent and only 1 mol % Pd(OAc)2 catalyst, the target 5-arylated thiophenes were obtained in moderate to good yields with a wide variety of aryl halides; whereas the use of 1-(4-methylthiophen-3-yl)-pyrrole affords the C2-arylated thiophenes. The sequential palladium catalysed 2,5-diheteroarylation of such 3-(pyrrol-1-yl)thiophene is also reported allowing the access to thiophenes bearing two different aryl units at C2 and C5. A pyrazole bearing an ester substituent at C4 and a pyrrole substituent at C5 was only arylated at C2 on the pyrrole ring

Syntheses of new benzoxazole derivatives

International audience2-(Arylidene)cyanomethylbenzoxazoles have been prepared in water from benzoxazole-2-ylacetonitriles. Using multi-component reactions, a variety of heterocycles containing benzoxazole and nitrile functionality has been prepared

Association of LRP5 genotypes with osteoporosis in Tunisian post-menopausal women

Osteoporosis is a highly heritable trait. Among the genes associated with bone mineral density (BMD), the low-density lipoprotein receptor-related protein 5 gene (LRP5) has been consistently identified in Caucasians. However LRP5 contribution to osteoporosis in populations of other ethnicities remains poorly known

3-Amino-4-(1,3-benzoxazol-2-yl)-5-(cyclohexylamino)thiophene-2-carbonitrile

In the title compound, C18H18N4OS, the cyclohexyl ring adopts a chair conformation. The other rings of this compound lie almost in the same plane, with a mean deviation of 0.03 (2) Å from the least-squares plane defined by the 14 constituent atoms. There are intramolecular N—H...N and N—H...O hydrogen bonds, as well as intermolecular N—H...N hydrogen bonds, which link the molecules into centrosymmetric dimers