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Electroreductive intramolecular cyclization of bromoalkoxylated derivatives cat...
Medeiros, M. J.; Neves, C. S. S.; Pereira, A. R.; Duñach, E.The (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetra-decane)nickel(I), [Ni(tmc)]+, electrogenerated at glassy carbon cathodes is shown to be an effective catalyst for the intramolecular radical-type cyclisation of bromoalkoxylated derivatives 1 in alcohol and / or alcohol/water mixtures as well as in microemulsions made with cationic and anionic surfactants. The results obtained indicate that the reaction pro...
Electrosynthesis of nitrogen heterocycles using environmentally friendly method...
Chaminade, X.; Duñach, E.; Esteves, Ana Paula; Medeiros, Maria José; Neves, C. S. S.; Olivero, S.Cyclic voltammetry and constant-current electrolysis in a one-compartment cell with a sacrificial anode has been used to study the indirect electroreduction of N-allyl- -haloamides by electrogenerated Ni(I) complexes conducted inN,N-dimethylformamide (DMF) and acetonitrile (ACN) and the resultswere compared with those obtained in protic solvents such as EtOH and EtOH–H2O mixtures. It was observed that the indir...
Organic cyclisations of propargyl and allyl bromoesters in microemulsions catal...
Esteves, Ana Paula; Neves, C. S. S.; Medeiros, Maria José; Pletcher, D.While the reductive intramolecular cyclisation of propargyl and allyl bromoesters catalysed by [Ni(tmc)]+ gives good yields of the desired products using N,N-dimethylformamide as the solvent, the use of this aprotic solvent presents practical, safety and environmental issues. This paper therefore reports the search for non-toxic alternatives, in particular the study of microemulsions prepared from water, hydroc...
Radical-type reactions in protic and aprotic media : comparisons in nickel-cata...
Dunach, E.; Esteves, Ana Paula; Medeiros, Maria José; Neves, C. S. S.; Olivero, S.The electrochemical reductive cyclisation of unsaturated organic halides in the presence of Ni(II) complexes as catalysts was examined in aprotic solvents such as DMF and in protic solvents such as ethanol, butanol or ethanolewater mixtures. The presence of the alcohol media enhanced the rate of recycling of the catalytic species. ; La cyclisation réductive électrochimique d’halogénures insaturés en présence d...
Synthesis of heterocyclic compounds by radical electrochemical approach in envi...
Duñach, E.; Esteves, Ana Paula; Neves, C. S. S.; Medeiros, Maria JoséRadical cyclisation is rapidly becoming an important method for the formation of cyclic systems. Hence, some electrochemical results obtained in the study of electroreductive intramolecular cyclisation of ethyl 2-bromo-3-(3,4-methylenedioxophenyl)-3-(propargyloxy)propanoate (1a), [1-bromo-2-methoxy-2-(prop-2’-ynyloxy) ethyl] benzene (1b) and 1-[2-bromo-2-phenyl-1-(prop-2’-ynyloxy)ethyl]-4-methoxybenzene (1c) pr...
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