Search results for "Compostos orgànics Síntesi"
showing 10 items of 10 documents
Copper-Catalyzed Aerobic Oxidative Alkynylation of 3,4-Dihydroquinoxalin-2-ones
2019
Herein, we described a ligand-free copper-catalyzed aerobic oxidative functionalization of 3,4-dihydroquinoxalin-2(1H)-ones with terminal alkynes using visible-light and oxygen as terminal oxidant to give 3-ethynyl-3,4-dihydroquinoxalin-2(1H)-one, cyclic propargylic amines, in moderate to good yields. Moreover, we demonstrate the versatility of the 3-ethynyl-3,4-dihydroquinoxalin-2(1H)-ones obtained by preparing several 3,4-dihydroquinoxalin-2-one derivatives.
Synthesis of Multisubstituted 1,4-Dihydrobenzoxazin-2-ones through a One-Pot Nucleophilic N-Alkylation/C-Alkylation of Cyclic α-Imino Esters
2017
A nucleophilic N-alkylation of 2-oxobenzoxazine-2-carboxylates with organozinc reagents with good selectivities and in moderate to good yields is described. Moreover, the synthesis of multisubstituted 1,4-dihydrobenzoxazine-2-ones bearing a tetrasubstituted carbon atom via a one-pot N-alkylation/C-alkylation reactions is reported.
Synthesis and antibacterial activities of cadiolides A, B and C and analogues
2015
International audience; The one-pot multicomponent synthesis of natural butenolides named cadiolides A, B, C and analogues has been realized. The antibacterial structure activity relationship shows that the presence of phenolic hydroxyl groups and the number and position of bromine atoms on the different aromatic rings are important features for antibacterial activity, besides it was demonstrated the tolerance of both benzene and furan ring at position 3 of the butenolide nucleus. Furthermore, none of the most relevant antibacterial compounds showed any cytotoxicity in freshly isolated human neutrophils.
Bis(imidazolium) salts derived from amino acids as receptors and transport agents for chloride anions
2015
The binding properties of bis(imidazolium) hosts 1a–c derived from amino acids towards different anions have been studied by 1H NMR titration experiments in 95 : 05 CD3CN : H2O at 303 K, ESI-MS and theoretical calculations. Among this family, the salt 1c showed a strong and high selectivity for chloride anions. Transmembrane chloride transport activity has also been studied for the three bis(imidazolium) based transporters in POPC liposome models, and compound 1a was identified as an active chloride/nitrate exchanger.
2,3,9- and 2,3,11-Trisubstituted tetrahydroprotoberberines as D2 dopaminergic ligands
2013
Dopamine-mediated neurotransmission plays an important role in relevant psychiatric and neurological disorders. Nowadays, there is an enormous interest in the development of new dopamine receptors (DR) acting drugs as potential new targets for the treatment of schizophrenia or Parkinson's disease. Previous studies have revealed that isoquinoline compounds such as tetrahydroisoquinolines (THIQs) and tetrahydroprotoberberines (THPBs) can behave as selective D-2 dopaminergic alkaloids since they share structural similarities with dopamine. In the present study we have synthesized eleven 2,3,9- and 2,3,11-trisubstituted THPB compounds (six of them are described for the first time) and evaluated…
Palladium-catalysed direct cross-coupling of secondary alkyllithium reagents
2014
Palladium-catalysed cross-coupling of secondary C(sp(3)) organometallic reagents has been a long-standing challenge in organic synthesis, due to the problems associated with undesired isomerisation or the formation of reduction products. Based on our recently developed catalytic C-C bond formation with organolithium reagents, herein we present a Pd-catalysed cross-coupling of secondary alkyllithium reagents with aryl and alkenyl bromides. The reaction proceeds at room temperature and on short timescales with high selectivity and yields. This methodology is also applicable to hindered aryl bromides, which are a major challenge in the field of metal catalysed cross-coupling reactions.
Multivariate sodalite Zeolitic Imidazolate frameworks: a direct solvent-free synthesis
2021
Different mixed-ligand Zeolitic Imidazolate Frameworks (ZIFs) with sodalite topology, i.e. isoreticular to ZIF-8, unachievable by conventional synthetic routes, have been prepared using a solvent-free methodology. In particular, the versatility of this method is demonstrated with three different metal centres (Zn, Co and Fe) and binary combinations of three different ligands (2-methylimidazole, 2-ethylimidazole and 2-methylbenzimidazole). One combination of ligands, 2-ethylimidazole and 2-methylbenzimidazole, results in the formation of SOD frameworks for the three metal centres despite this topology not being obtained for the individual ligands. Theoretical calculations confirm that this t…
A tris-oxovanadium pyrogallate complex: synthesis, structure, and magnetic and electronic properties
2021
International audience; With the aim of identifying new cation-phenolate complexes, we herein investigated the reactivity of pyrogallol (H(3)pgal) with vanadium salts. A trimetallic anionic complex was identified, and found to be formed under a broad set of reaction conditions. This complex, with the formula V3O3(pgal)(3)(3-), consists of three oxovanadium(iv) units connected together by three pyrogallate ligands to afford a bowl-shaped species presenting a pseudo 3-fold symmetry axis. Its crystal structure is reported, as well as its characterisation by a broad set of techniques, including powder X-ray diffraction, thermogravimetric analysis, infrared and Raman spectroscopy, and solid stat…
Use of alkylarsonium directing agents for the synthesis and study of zeolites
2019
[EN] Expanding the previously known family of -onium (ammonium, phosphonium, and sulfonium) organic structure-directing agents (OSDAs) for the synthesis of zeolite MFI, a new member, the arsonium cation, is used for the first time. The new group of tetraalkylarsonium cations has allowed the synthesis of the zeolite ZSM-5 with several different chemical compositions, opening a route for the synthesis of zeolites with a new series of OSDA. Moreover, the use of As replacing N in the OSDA allows the introduction of probe atoms that facilitate the study of these molecules by powder X-ray diffraction (PXRD), solid-state nuclear magnetic resonance (MAS NMR), and X-ray absorption spectroscopy (XAS)…
Bioaccessibility Study of Aflatoxin B1 and Ochratoxin A in Bread Enriched with Fermented Milk Whey and/or Pumpkin
2021
The presence of mycotoxins in cereals and cereal products remains a significant issue. The use of natural ingredients such as pumpkin and whey, which contain bioactive compounds, could be a strategy to reduce the use of conventional chemical preservatives. The aim of the present work was to study the bioaccessibility of aflatoxin B1 (AFB1) and ochratoxin (OTA) in bread, as well as to evaluate the effect of milk whey (with and without lactic acid bacteria fermentation) and pumpkin on reducing mycotoxins bioaccessibility. Different bread typologies were prepared and subjected to an in vitro digestion model. Gastric and intestinal extracts were analyzed by HPLC–MS/qTOF and mycotoxins bio…