Amines as leaving groups in nucleophilic aromatic substitution reactions. Part 5.1 Substitution vs. N-oxide formation in the reaction of N-n-butyl-2,6-dinitroaniline with hydroxide ions
Buján, Elba I.; Cañas, A. Irene; de Rossi, Rita H.; Buján Elba I.; Instituto de Investigaciones en FisicoquÃmica de Córdoba, INFIQC, Departamento de QuÃmica Orgánica, Facultad de Ciencias QuÃmicas; Cañas A. Irene; Instituto de Investigaciones en FisicoquÃmica de Córdoba, INFIQC, Departamento de QuÃmica Orgánica, Facultad de Ciencias QuÃmicas; de Rossi Rita H.; Instituto de Investigaciones en FisicoquÃmica de Córdoba, INFIQC, Departamento de QuÃmica Orgánica, Facultad de Ciencias QuÃmicas
Журнал:
Journal of the Chemical Society, Perkin Transactions 2
Дата:
2001
Аннотация:
A kinetic study of the reaction of N-n-butyl-2,6-dinitroaniline 1 with NaOH was carried out in 10% 1,4-dioxaneâ water at 25â °C, giving 2,6-dinitrophenol 2 and 7-nitro-2-n-propyl-1H-benzimidazole 3-oxide 3 in ratios depending on the HO<sup>â </sup>concentration. The rate constant for the formation of 2 is second order in HO<sup>â </sup> concentration while that of 3 is first order then, the relative amount of 2â â ¶â 3 formed increases with HO<sup>â </sup>. A mechanism involving the formation of a Ï complex by addition of HO<sup>â </sup> to an unsubstituted position of the aromatic ring is proposed for 2,6-dinitrophenol formation. The mechanism suggested for the formation of the N-oxide requires the deprotonation of the substrate.
129.3Кб