Synthesis of benzimidazolyl-1,3,4-oxadiazol-2ylthio-N-phenyl (benzothiazolyl) acetamides as antibacterial, antifungal and antituberculosis agents

To affiliate multiple bioactivities in a compact heteronuclei, two series of benzimidazole based 1,3,4-oxadiazoles were synthesized and assessed in vitro for their efficacy as antimicrobial agents against eight bacteria (Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Proteus vulgaris, Shigella flexneri), four fungi (Aspergillus niger, Aspergillus fumigatus, Aspergillus clavatus, Candida albicans) and Mycobacterium tuberculosis H37Rv and best results were observed amongst the N–benzothiazolyl aetamide series. The lipophilicity (LogP) influence on the biological profile (MICs) of the prepared products was also discussed. Upon biological screening, it was observed that the majority of the compounds were found to possess a significant broad spectrum antimicrobial (3.12–25 μg/mL of MIC) and antitubercular (6.25–25 μg/mL of MIC) potential. The structural assignments of the new products were done on the basis of IR, 1H NMR, 13C NMR spectroscopy and elemental analysis.

Twenty two new benzimidazolyl oxadiazoles have been synthesized and screened against bacteria, fungi and mycobacteria. The results indicated that some derivatives were potentially active.Figure optionsDownload as PowerPoint slideHighlights
► Benzimidazolyl–1,3,4–oxadiazol–2ylthio–N–phenyl(benzothiazolyl)acetamides were synthesized.
► Newer analogues were tested in vitro against twelve pathogenic bacteria, fungi and Mycobacterium tuberculosis H37Rv.
► Compounds linked with benzothiazolyl acetamides showed improved potency than phenyl acetamides.
► Compound 6i identified as a promising inhibitor of M. tuberculosis H37Rv.
► Compounds serve as potential leads for further drug discovery study.