Hetarynes. Part XV: <i>N</i>‐oxides of 2,3‐ and 3,4‐pyridyne

Abstract

Abstract The action of potassium amide in liquid ammonia on the N ‐oxides of 2‐, 3‐ and 4‐bromopyridine, 3‐fluoropyridine, 2‐ and 3‐bromo‐4‐methylpyridine, 3‐ and 4‐bromo‐5‐ethoxypyridine and 3‐ and 4‐bromo‐2,5‐dimethylpyridine has been investigated. 3‐Fluoropyridine‐ N ‐oxide does not react under the conditions applied; the other N ‐oxides yield mixtures containing one or two amino compounds. The mechanisms of the formation of these substances are discussed. It was established that the S N Ar 2 (= AE) reaction is almost the sole reaction pattern in the aminations of the 4‐bromopyridine‐ N ‐oxides and one of the mechanisms occurring in the aminations of the 2‐bromopyridine‐ N ‐oxides. The 2‐bromopyridine‐ N ‐oxides react partially and the 3‐bromopyridine‐ N ‐oxides exclusively via 2,3‐pyridyne‐ N ‐oxides as intermediates, except the N ‐oxides of 3‐bromo‐2,5‐dimethylpyridine and 3‐bromo‐5‐ethoxypyridine in the aminations of which 3,4‐pyridyne‐ N ‐oxides play a role.