Microwave-assisted and conventional synthesis of novel antimicrobial 1,2,4-triazole derivatives containing nalidixic acid skeleton

Carbothioamides , obtained from nalidixic acid, were converted to the corresponding 1,3-thiazolidine derivatives by cyclocondensation with 2-bromo-1-(4-chlorophenyl)ethanone. Treatment of with base afforded 1,2,4-triazoles . The synthesis of 1,3-oxazolidine was performed by the reaction of compound with ethyl bromoacetate. Treatment of with acid produced 1,3,4-thiadiazole . The reaction of compounds and with several heterocyclic amines in the presence of formaldehyde gave the corresponding Mannich bases containing various pharmacophore groups. Conventional and microwave-assisted methods were used for the synthesis. The effect of an acid catalyst on Mannich reactions was investigated. The structures of the newly synthesized compounds were elucidated on the basis of H NMR, C NMR, FTIR, EIMS techniques, and elemental analysis. All compounds were screened for their antimicrobial activity.