Unsaturated amino acids derived from isoleucine trigger early membrane effects on plant cells

International audienc

La réaction de cycloaddition [3+2] dipolaire assistée par micro-ondes

La réaction de cycloaddition dipolaire [3+2] est un outil puissant pour la préparation de composés hétérocycliques. C'est une méthode facile à mettre en œuvre, tant ses conditions opératoires sont douces, qui nécessite, de plus des réactifs aisément accessibles et peu onéreux. Dans ce manuscrit, nous décrivons l'étude de la réaction de cycloaddition dipolaire à partir d'ylures d'azométhine sous irradiation micro-ondes. L'association de la cycloaddition dipolaire [3+2] avec la chimie des micro-ondes s'est révélée être d'une grande efficacité pour la préparation de plusieurs composés polycycliques en peu d'étapes. Les résultats intéressants obtenus, offrent une nouvelle approche synthétique applicable à la synthèse de nouvelles molécules bioactives. Par conséquent, nous avons préparé un grand nombre de composés potentiellement actifs, de type hydropyrrolique, comme des hydrochroménopyrroles, des hydrobenzoindoles, des hydroindénopyrroles et des oxochroménopyrroles. Ces composés ont pu être préparés dans des temps très courts, avec des rendements généralement très bons.The [3+2] dipolar cycloaddition reaction is a powerful tool for the preparation of heterocyclic compounds. It is a facile method, employing straight forward laboratory procedures, and easily accessible reagents. Herein we describe the study of the dipolar cycloaddition reaction from azomethine ylides under microwave conditions. The use of microwaves in this reaction is very efficient for the rapid synthesis of polycyclic compounds. The interesting results obtained permit the development of novel methodology for the synthesis of many molecules with pharmacological potential. As such, we prepared numerous families of compounds such as hydrochromenopyrroles, hydrobenzoindoles, hydroindenopyrroles and oxochromenopyrroles. These compounds were prepared rapidly, generally in very good yields.POITIERS-BU Sciences (861942102) / SudocSudocFranceF

Molecular biomarkers study of an ombrotrophic peatland impacted by an anthropogenic clay deposit

International audienceNorthern peatlands are estimated to store up to one third of all terrestrial carbon as peat and, even though a large extent of boreal peatlands is in pristine condition, extensive areas have been affected by natural or anthropogenic disturbance. Here, we aimed to study the bulk organic matter, elemental composition and molecular inventory of a peat disturbed by a clay deposit in the mesotelm layer (from −35 to −45 cm) due to mining activity near the peatland zone. We therefore investigated loss on ignition, elemental analysis, lignin monomers and non-cellulose carbohydrates, as well as the lipid fraction. In general, no significant impact on peatland evolution was noted, the only odd result being an increase in complex lipids containing acyl groups in the clay deposit zone, although this did not influence the distributions of the fatty acids, which had a bimodal distribution at C16 and C24/C26, typical of a non-impacted Sphagnum dominated peatland. Phospholipid analysis showed an increase in the quantity of mid-chain branched fatty acids, suggesting high sulfate reducing activity in the underlying clay deposit. Other lipid, lignin and carbohydrate biomarkers showed a normal peatland evolution, plant deposition being apparent in the bottom layer designated by the catotelm and microbial activity and production being highest in the upper layer, represented by the acrotelm and mesotelm

Molecular fingerprint of soil organic matter as an indicator of pedogenesis processes in Technosols

International audienc