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

Pistacia vera L. leaves as a renewable source of bioactive compounds via microwave assisted extraction

The production of pistachio in Tunisia generates a large amount of potentially valuable waste, such as leaves, that could be used as source of bioactive compounds. In this work, the extraction of phytochemicals from Pistacia vera L. leaves (male and female) by microwave-assisted extraction (MAE) has been investigated. A response surface methodology (RSM) was used for the optimization of bioactive compounds extraction, where the independent variables were temperature and extraction time, and the dependent variable was extraction yield. Total phenolic content (TPC), total flavonoid content (TFC), antioxidant activities (DPPH, ABTS, and FRAP) and antimicrobial activity of the extracts obtained at optimal conditions for both leaves were evaluated and compared not only between them, but also with the extracts obtained by maceration. The optimum extraction conditions were 70 ? and 61 ?, and 5.6 and 12 min for male and female leaves respectivily. The best results were achieved for female leaves by MAE with 36% of extraction yield, TPC of 196.35 mg gallic acid equivalents (GAE)/g dry weight (DW), TFC of 83.34 mg catechin equivalents (CE)/g dry weight (DW), and high antioxidant and antimicrobial activities. The evaluation of biological activity of the extracts showed that MAE provides extracts with better antioxidant and antimicrobial capacities then those obtained by maceration. More-over, UPLC-DAD-ESI-MS was performed to confirm the presence of some phenolic compounds in MAE extracts, such as quercetin, apigenin and myricetin derivatives. The results revealed that MAE is an efficient technique for the extraction of active components from Pistacia vera L. leaves.The authors greatly acknowledge the financial support of the Ministry of Higher Education and Scientific Research of Tunisia. L.S. would like to thank to the Spanish Ministry of Universities for the Margarita Salas fellowship for the requalification of the Spanish university system financed by the European Union -Next GenerationEU

Etude piezochimique du transfert d'hydrogene dans les reactions eniques

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Effect of daily or intermittent addition of fenugreek (Trigonella foenum graecum L.) seeds to concentrate on intake, digestion, and growth performance of Barbarine lamb

International audienceAn 82-day experiment was carried out to determine the response of growing lambs to the intermittent administration of fenugreek (FG) seeds (Trigonella foenum graecum L.) into concentrate. Twenty-Four 3-month-old Barbarine lambs (initial body weight 16.6 ± 0.42 kg) were divided into four equal groups (n = 6). All lambs received 600 g alfalfa pellets and 250 g concentrate containing or not 12% ground FG seeds. Control concentrate (CC) was composed (as fed) of barley (200 g), faba bean (40 g) and mineral and vitamin supplement (MVS, 14 g). The experimental concentrate (CE) contained barley (200 g), FG seeds (30 g) and MVS (14 g). The two concentrates have the same crude protein content. The control group (FG-0) received CC while groups FG-D, FG-2D and FG-4D received CE daily, or in alternation with concentrate CC at 2 or 4-day intervals (FG-2D or FG-4D, respectively). The feeding trial was followed by a 5-day in vivo digestibility trial. The frequency of distribution of FG-containing concentrate (CE) had no effect (P > 0.05) on diet intake and diet apparent digestibility of dry matter, organic matter, crude protein and cell wall (NDFom), nitrogen balance and the concentrations of urea, total protein and glucose in sheep plasma. The intermittent supply of FG seeds in concentrate tended to increase (P = 0.087)the average daily gain in FG-2D and FG-4D lambs and the microbial nitrogen synthesis (P = 0.052)with the FG administration. However, it decreased (P < 0.001) ruminal protozoa count by 33%, 44% and 66% in the FG-D, FG-2D and FG-4D lambs, respectively compared to FG-0 group. Similarly, the intermittent administration of FG seeds decreased ruminal ammonia nitrogen (NH3-N) concentrations (P < 0.001) by 28%, 31% and 35% in the FG-D, FG-2D and FG-4D, respectively. The antiprotozoal activity of FG seeds could have been induced by secondary compounds like saponins. This activity was more efficient when the frequency of incorporation of FG seeds into the concentrate is wider. It is concluded that the intermittent administration of 120 g/kg to concentrate (DM basis), had an antiprotozoal effect but failed to improve diet digestibility and growth performance of Barbarine lambs. Therefore, there is a need to emphasize further investigation to identify the active components responsible for the antiprotozoal activity of FG seeds

Synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones via Biginelli reaction promoted by bismuth(III)nitrate or PPh3 without solvent

3,4-Dihydropyrimidinones/thiones and their derivatives are synthesized via Biginelli routes involving an aldehyde, 1,3-dicarbonyl compound and urea or thiourea. Use of catalysts such as bismuth nitrate in acetonitrile or PPh3 without solvent lead to higher yields compared to the classic method using HCl in ethanol. In such way, 3,4-dihydropyrimidinones which are hardly prepared under classic conditions can be synthesized with fair yields