β‐Aminoketone als Schlüsselverbindungen zur Synthese von Pyridinen: Ein neuartiger, leistungsfähiger Zugang zu kondensierten Bi‐ und Terpyridinen

β‐Amino Ketones as Key Intermediates in the Synthesis of Pyridines: A Novel and Efficient Route to Annelated Bi‐ and Terpyridines The hydrochlorides of β‐amino ketones 1a – e (Mannich bases) are easily obtained starting compounds for a novel synthesis of pyridines. Condensation with the heteroaromatic ketones 8, 9 , and 10 yields 5,6‐dihydro‐1,10‐phenanthrolines 3a – d, 13 and 4,5‐diazafluorenes 4a – d , which have not yet been described in literature. Symmetrical terpyridines 3e, 4e are formed in a one‐step reaction of 8, 9 with dimethylmethylenammonium chloride in the presence of an ammonia source.