New 2-benzylsulfanyl-nicotinic acid based 1,3,4-oxadiazoles: Their synthesis and biological evaluation

A novel series of 5-(2-benzylsulfanyl-pyridin-3-yl)-2-(substituted)-sulfanyl-1,3,4-oxadiazoles 6a–j were synthesized from key intermediate 5-(2-benzylsulfanyl-pyridin-3-yl)-3H-[1,3,4]oxadiazole-2-thione 5. Nucleophilic substitution reactions with different electrophiles (E+), such as haloacetate and haloalkyl groups, were performed to get target compounds 6a–j. Compounds were characterized by NMR, mass, IR spectra and C, H, N analyses. All compounds were evaluated for their antimicrobial and antimycobacterial activities; selected analogs were screened for their anticancer activity on 60 tumor cell lines at single dose 1.00−5 M. Unfortunately, none of the compounds showed a significant antitumor activity on 60 human tumor cell lines. However, compounds 6g and 6f with benzothiazole moiety (12.5 and 25 μg/ml) showed promising activity against Escherichia coli compared to ampicillin; compounds 6d, 6j bearing triazole and morpholine, respectively, showed promising antitubercular activity (25 μg/ml) compared to rifampicin.

5-(2-Benzylsulfanyl-pyridin-3-yl)-2-(substituted)-sulfanyl-1,3,4-oxadiazoles 6a–j were synthesized and their antimicrobial activity, antimycobacterial activity and antitumor activity have been screened.Figure optionsDownload as PowerPoint slideHighlights
► New 2-benzylsulfanyl-nicotinic acid incorporated 1,3,4-oxadiazoles were synthesized.
► In vitro antimicrobial, antimycobacterial and anticancer activities have been studied.
► 2-Thiobenzyl nicotinic-oxadiazoles of thiazole, benzothiazole and epichlorohydrin showed good antimicrobial activity.
► Triazole attached 6d and morpholine 6j were found significant against Mycobacterium tuberculosis H37Rv.