Darstellung von 1‐Cyan‐4‐dimethylamino‐3‐(pyrid‐4‐yl)‐buta‐1,3‐dien‐1‐carbonsäure‐Derivaten und ihre Cyclisierung zu 3‐substituierten 2‐Amino‐5‐(pyrid‐4‐yl)‐pyridinen sowie den entsprechenden 1‐Oxiden

Synthesis of 1‐Cyano‐4‐dimethylamino‐3‐(4‐pyridinyl)‐1,3‐butadiene‐1‐carboxylic Acid Derivatives and Their Cyclisation to 3‐Substituted 2‐Amino‐5‐(4‐pyridinyl)‐pyridines Including the Corresponding 1‐Oxides The vinylogous amidinium salt 1 is transformed to 1‐cyano‐4‐dimethylamino‐3‐(4‐pyridinyl)‐1,3‐butadiene‐1‐carboxylic acid derivatives 3a ‐ f by reaction with the cyanoacetic acid compounds 2a ‐ f in the presence of bases. Treatment of the 3a ‐ f with ammonia and hydroxylamine yields the 2‐amino‐5‐(4‐pyridinyl)‐pyridine‐3‐carboxylic acid derivatives 5a ‐ f and the corresponding 1‐oxides 6a ‐ f , respectively. The products 5d , e are also prepared via the 6d , e by reduction with phosphorus trichloride.