Anil‐Synthese 22. Mitteilung über die Herstellung von Styryl‐und Distyryl‐Derivaten des Pyridins

Preparation of Styryl and Distyryl Derivatives of Pyridine 2,4‐, 2,5‐ and 2,6‐Dimethylpyridines react with anils of aromatic aldehydes in the presence of dimethylformamide and potassium hydroxide to yield the corresponding distyrylpyridines (‘anil synthesis’). Under the same reaction conditions (4‐methylstyryl)pyridines are converted to (stilbenylvinyl)pyridines. Similarly, the Schiff's base derived from pyridine‐3‐carbaldehyde and p ‐chloroaniline on treatment with methyl‐ and p ‐tolyl‐substituted aromatic heterocycles gives the corresponding (heteroaryl‐styryl)pyridines, whereas with the Schiff's bases derived from pyridine‐2‐ and ‐4‐carbaldehyde side reactions, such as dimerization followed by disproportionation predominate.