Palladium‐Catalyzed Amination of 3,5‐Dihalopyridines – a Convenient Route to New Polyazamacrocycles

Pd‐Catalyzed amination of 3,5‐dibromo‐ and 3,5‐dichloropyridine ( 1a and 1b , resp.) with linear polyamines 2 leads to the formation of a new family of pyridine‐containing macrocycles 3 with an ‘exo’‐oriented pyridine N‐atom (Schemes 1 and 2). The dependence of the macrocycle yield on the nature of the halogen atom, the length of the polyamine chain and C/N atom ratio, and the composition of the catalytic system is studied. The synthesis of mono‐ and bis(5‐halopyridin‐3‐yl)‐substituted polyamines 4, 5, 8, 9 , and of 3,5‐bis(polyamino)‐substituted pyridines 6 is described (Schemes 3 and 4), and the use of these compounds as intermediates on the way to the macrocycles 7, 16 , and 18 with larger cavity (‘cyclodimers’ and ‘cyclotrimers’) is demonstrated (Schemes 5–10).