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Synthesis, NMR and DFT conformational studies of homooxacalixarene (cyanopropyl)oxy derivatives, precursors to urea-terminated compounds
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Orientador(es)
Resumo(s)
Direct O-alkylation of the parent compounds p-tert-butyldihomooxacalix[4]arene (1) and p-tertbutylhexahomotrioxacalix[3]arene (3) with 4-bromobutyronitrile and K2CO3 in acetonitrile afforded tetra- and tri-[(cyanopropyl)oxy] derivatives 2 and 4, respectively, as a mixture of conformers. These conformers were isolated and their conformational features studied by NMR spectroscopy (1H, 13C, COSY and NOESY) and DFT methods. Dihomooxacalix[4]arene tetra[(cyanobutyl)oxy] derivative 5 was also obtained and studied for comparison purposes. In general, good agreement was obtained between theoretical calculations and the NMR experimental data. For compounds 2 and 4 the partial cone conformation was the most stable, while the cone conformation was the most stable for derivative 5.
Descrição
Palavras-chave
Homooxacalixarenes Synthesis Cyano derivatives Conformational analysis NMR spectroscopy DFT methods
Contexto Educativo
Citação
Paula M. Marcos, Carla S. Proença, Filipa A. Teixeira, José R. Ascenso, Raul J. Bernardino, Peter J. Cragg, Synthesis, NMR and DFT conformational studies of homooxacalixarene (cyanopropyl)oxy derivatives, precursors to urea-terminated compounds, Tetrahedron, Volume 69, Issue 35, 2013, Pages 7430-7437, ISSN 0040-4020, https://doi.org/10.1016/j.tet.2013.06.048.
Editora
Elsevier