Synthesis of new 2‐pyridinone and thiazole derivatives containing coumarin moiety

Coumarin has shown considerable therapeutic potency because of its versatile biological prosperities. Also, pyridines have been adopted in medicinal chemistry as potent ring. Moreover, several investigations reported the potency of thiazole‐containing compounds. So, during this research, new functionalized 2‐pyridinone and thiazole derivatives bearing coumarin moiety were aimed to synthesize. Many trials to obtain the 6‐amino‐2‐oxo‐pyridine‐3,5‐dicarbonitriles through the condensation of cyanoacetohydrazone of 3‐acetyl coumarin with 2‐(arylidene)malononitriles were carried out using different reaction conditions. In all cases, the reaction gave none of the corresponding 2‐pyridinone derivatives except the reaction with 2‐(benzylidene)‐malononitrile afforded product in few yield. Moreover, the reaction of another cyanoacetanilide with the 2‐(arylidene)‐malononitrile afforded the unexpected arylidene derivatives rather than the expected pyridin‐2‐one derivatives. Finally, new thiazoles bearing coumarin moiety were synthesized using 3‐acetylcoumarin N‐(2,4‐dimethoxyphenyl)‐thiosemicarbazone. Cyclization of thiosemicarbazone derivative with ethyl 2‐chloroacetate, chloroacetone or phenacyl bromide afforded in high yields the corresponding derivatives of thiazolidin‐4‐one, 4‐methylthiazole or 4‐phenylthiazole, respectively. The trials to obtain the 2‐pyridinones (6‐amino‐2‐oxo‐pyridine‐3,5‐dicarbonitriles) through the reaction of cyanoacetamide derivatives with the 2‐(arylidene)‐malononitriles.