Rearrangements during aminations of halopyridines, presumably involving a pyridyne intermediate

Abstract

Abstract When reacted with potassium amide in liquid ammonia, both 3‐chloro and 4‐chloropyridine are converted into a mixture containing 3‐amino and 4‐aminopyridine in a ratio of 1:2. The same reaction product results from the animations of 3‐iodo and 4‐iodopyridine. The course of these reactions can be explained by a mechanism involving 3,4‐pyridyne as an intermediate. 2‐Chloro and 2‐iodopyridine only yield 2‐aminopyridine. Rearrangements via ethoxy derivatives of 3,4‐pyridyne probably proceed in aminations of 3‐bromo‐6‐ethoxypyridine and 4‐bromo‐5‐ethoxypyridine. A shift of the substituent from position 3 to 2 occurs in the amination of 3‐bromo‐4‐ethoxypyridine which yields 2‐amino‐4‐ethoxypyridine. An abnormal rearrangement takes place during the amination of 2‐bromo‐6‐ethoxypyridine, 4‐amino‐6‐ethoxypyridine together with 2‐amino‐6‐ethoxypyridine being formed.