Synthesis of Mannich bases of some 2,5-disubstituted 4-thiazolidinones andevaluation of their antimicrobial activities

5-Phenyl/methyl-5-morpholinomethyl/pyrrolidinomethyl-2-(5-aryl-1,3,4-oxadia zol-2-yl) imino]-4-thiazolidinones (5a-m) were synthesized by the reaction of 5-phenyl/methyl-2-[(5-aryl-1,3,4-oxadiazol-2-yl)imino] -4-thiazolidinone s (4a-j) with formaldehyde and morpholine or pyrrolidine. The structures of the compounds were determined by analytical and spectral (IR,H-1-NMR, EIMS ) methods. The antibacterial activities of the novel compounds against Stap hylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, Escheri chia coli ATCC 8739, Klebsiella pneumoniae ATCC 4352, Pseudomonas aeruginos a ATCC 1539, Salmonella typhi, Shigella flexneri and Proteus mirabilis and antifungal activity against Candida albicans ATCC 10231 were tested using t he disk diffusion method. Compounds 5a, 5b, 5c, 5e, 5g, and 5h were found t o be active against S. aureus ATCC 6538 (MIC: 312.5; 39; 19.5; 39; 156; and 78 mug/mL respectively) and compounds 5e and 5h against S. flexneri (MIC: both 312.5 mug/mL). The minimal inhibitory concentrations of these compound s were determined using the micro dilution method.