Synthesis of Novel 3-Acetyl N-methyl-2- Quinolone Derivatives with Expected Antimicrobial Activity

A series of new 3-Acetyl N-Methyl-2-quinolones oxadiazoles derivatives were synthesized by reaction of 3-acetyl-4-hydroxy-1-methylquinolin-2(1H)-one 3 with ethylbromoacetate to produce compounds 4. The hydrazinolysis of compound 4 with hydrazine hydrate afforded hydrazide compounds 5. New Schiff bases 6 were obtained by condensation of compound 5 with different aryl aldehydes. The last step involves refluxing compound 6 with acetic anhydrides to give the corresponding 3-acetyl-N-methylquinolin-2-one oxadiazoles 7. All the synthesized compounds were characterized on the basis of FT-IR, 1H-NMR and 13C-NMR. The synthesized compounds have been evaluated for antimicrobial activity against Gram-positive and Gram-negative bacteria. Among sixteen synthesized novel compounds, in which five compounds (7a, 7b, 7c, 7e, 7g) ex-hibited promising Antimicrobial activity as compared to Trimethoprim (100μg/ml).