N-oxide formation in competition with amine substitution in the reaction of N-alkyl derivatives of 4-substituted 2,6-dinitroanilines in basic media

ELBA I. BUJÁN; MARÍA LAURA SALUM

Isla de Margarita

Conferencia; 6ta. Conferencia Latinoamericana de Fisicoquímica Orgánica; 2001

Universidad Central de Venezuela

wWe have studied the reaction of N-butyl-2,6-dinitro-4-Z-aniline 1 at 25ºC in 10% and 60% dioxane-water. The reaction of compuond 1a in 10% dioxane-water gives a mixture of 2a and 3a in ratios depending on the HO- concentratio. The same compound in 60% dioxane-water gives only 3a. When compound 1b reacts in 10% dioxane-water it gives quantitatively 2b. In 60% dioxane-water, a mixture of 2b and 3b inratios depending on the HO- concentration is formed. The reaction of compound 1c in 10% dioxane water leads to the formation of 2c and 3c in ratios depending on the HO- concentration. The rate constant for the formation of 2 is second order in HO- concentration while that of 3 is first order then, the relative amount 2/3 increases with HO/. The mechanism proposed for the formation of phenol involves sigma complexes formed by addition of HO- to unsubstituted positions of the aromatic ring that catalize t6he substitution of the amino group. The mechaniusm suggested for the formation of the n-oxide requires the deprotonation of substrate.