Aminations of bromo-derivatives of 4-ethoxy- and 2,4-diethoxy-pyridine, probably involving a 2,3-pyridyne as intermediate

✍ Scribed by M. J. Pieterse; H. J. den Hertog

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 443 KB
• Volume: 81
• Category: Article
• ISSN: 0165-0513
• DOI: 10.1002/recl.19620811005

✦ Synopsis

Abstract

The amination of 3‐bromo‐4‐ethoxypyridine with potassium amide in liquid ammonia yielding 2‐amino‐4‐ethoxypyridine as chief product has been reinvestigated. It is shown that 2‐amino‐5‐bromo‐4‐ethoxypyridine is formed as a byproduct, probably via 3,5‐dibromo‐4‐ethoxypyridine and 5‐bromo‐4‐ethoxy‐2,3‐pyridyne as intermediates.

In order to check the mechanism proposed for the process described above, aminations of 3‐ and 5‐bromo‐2,4‐diethoxypyridine were studied. Both reactions yield 6‐amino‐2,4‐diethoxypyridine as chief product. It was found that 3‐bromo‐2,4‐diethoxypyridine was converted first into the 5‐bromo‐isomer. It seems likely that in both aminations 2,4‐diethoxy‐5,6‐pyridyne is an intermediate.