Collect. Czech. Chem. Commun.
1991, 56, 2313-2325
https://doi.org/10.1135/cccc19912313
On the bipyridyl formation in reactions of 2-chloropyridine derivatives with potassium amide in liquid ammonia
Johannis W. Streefa, Henk C. van der Plasa and Sybolt Harkemab
a Laboratory of Organic Chemistry, Agricultural University Wageningen, 6703 HB Wageningen, The Netherlands
b Faculty of Chemical Technology, Technical University of Twente, Postbox 217, 7500 AE Enschede, The Netherlands
Abstract
In the reaction of 2,6-dichloropyridine and 2,6-dichloro-3-phenylpyridine with potassium amide in liquid ammonia at –70°C, formation of derivatives of 4,4’-bipyridyl and 3,4’-bipyridyl is observed. The 4,4’ coupling products are far in excess to the 3,4’ coupling products. When the reaction is carried out at –70°C in the presence of potassium permanganate, the corresponding 4-aminopyridines are the main products. 2-Chloro-6-phenoxypyridine is very unreactive with this aminating reagent at –70°C as well as –33°C, but in the presence of potassium permanganate at –33°C 4-amino-2-chloro-6-phenoxypyridine is formed in fair yield. The mechanisms of the formation of the bipyridyls and 4-aminopyridines are presented.
