Synthesis and Antimicrobial Activity of Some Novel Substituted Bis‐Pyridone, Pyrazole, and Thiazole Derivatives

Abstract

A variety of novel bis‐heterocyclic derivatives were synthesized via the reaction of bis‐cyanoacetanilide derivative 3 with various aromatic aldehydes (1:2 molar ratio), to give the corresponding bis‐arylidene derivatives 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5l, 5m. On the other hand, reacting compound 3 with substituted 2‐hydroxybenzaldehydes 6a, 6b, 6c afforded 2‐iminochromene‐3‐carboxamides 7a, 7b, 7c. The reaction of compound 5 with malononitrile afforded the novel bis‐pyridones 9a, 9b, 9c,9f, 9g, 9h. The reaction of 5 with hydrazine derivatives afforded pyrazoles 11a, 11b, 11c, 11d, 11e, 11f, respectively. Compound 3 reacts with phenyl isothiocyanate in the presence of potassium hydroxide at room temperature followed by addition of some different halo‐carbonyl compounds to afford bis‐poly‐functionalized thiazole derivatives 13a, 13b, 13c. The bis‐enamine derivative 15 reacts also with hydrazine hydrate, guanidine, and hydroxylamine to give bis‐pyrazole 17, pyrimidine 19, and isoxazole 21 derivatives, respectively. Some of the newly synthesized compounds show moderate to high antimicrobial activity.