Synthesis, antimicrobial activity and cytotoxicity of novel oxadiazole derivatives.

In the present study, 5-substituted-1,3,4-oxadiazolin-2-thiones (1a-b) were synthesized via the ring closure reactions of appropriate acid hydrazides with carbon disulphide. N-(Benzothiazol-2-yl)-2-[[5-substituted-1,3,4-oxadiazol-2-yl]sulfanyl]acetamide derivatives (3a-j) were obtained by the nucleophilic substitution reactions of 5-substituted-1,3,4-oxadiazolin-2-thiones (1a-b) with N-(benzothiazol-2-yl)-2-chloroacetamides. The chemical structures of the compounds were elucidated by IR, (1)H NMR, (13)C NMR and FAB(+)-MS spectral data and elemental analyses. The synthesized compounds were screened for their antimicrobial activities against Micrococcus luteus, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Candida albicans. All compounds except compound 3h exhibited the highest antibacterial activity against P. aeruginosa. Among all compounds (3a-j), the compounds bearing 4-methoxyphenoxymethyl moiety on oxadiazole ring (3a-e) exhibited the highest inhibitory activity against C. albicans. Although compound 3j did not possess 4-methoxyphenoxymethyl moiety on oxadiazole ring, this derivative also exhibited the same level of anti-candidal activity. The compounds were also investigated for their cytotoxic effects using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Compound 3a exhibited the highest cytotoxic activity, whereas compound 3g possessed the lowest cytotoxic activity against NIH/3T3 cells.

Synthesis, antimicrobial activity and cytotoxicity of some new carbazole derivatives.

In this work, some N-(9-Ethyl-9H-carbazole-3-yl)-2-(phenoxy)acetamide derivatives were synthesised and evaluated for their antimicrobial activity and cytotoxicity. The structural elucidation of the compounds was performed by IR, (1)H-NMR, (13)C-NMR and FAB(+)-MS spectral data and elemental analyses. The title compounds were obtained by reacting 2-chloro-N-(9-ethyl-9H-carbazole-3-yl)acetamide with some substituted phenols. The synthesised compounds were investigated for their antibacterial and antifungal activities against Micrococcus luteus, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Candida albicans. The compounds N-(9-Ethyl-9H-carbazole-3-yl)-2-(4-ethylphenoxy)acetamide (2c) and N-(9-Ethyl-9H-carbazole-3-yl)-2-(quinolin-8-yloxy)acetamide (2n) showed notable antimicrobial activity. The compounds were also studied for their cytotoxic effects using MTT assay, and it was seen that 2n had the lowest cytotoxic activity against NIH/3T3 cells.