Synthesis, antibacterial and anticancer evaluation of 5-substituted (1,3,4-oxadiazol-2-yl)quinoline

2-Chloroquinoline-3-carbaldehyde (2) was synthesized via Vilsmeier–Haack method using acetanilide. Phenoxy/naphthalene-1-yl/naphthalen-2-yloxy methyl-1H-benzimidazol-1-yl)acetohydrazide (7a–c) were synthesized using 2-[2-(phenoxy/naphthalen-1-yl/naphthalen-2-yloxy methyl)-1H-benzimidazol-1-yl]acetohydrazide (6a–c). The title compounds 2-chloro-3-{5-[(2-phenoxy/naphthalene-1-yl/naphthalen-2-yloxy methyl-1-H-benzimidazol-1-yl)methyl]-1,3,4-oxadiazol-2-yl}quinolone (8a–c) were prepared using chloramine-T. In the second series, (2-chloroquinolin-3-yl)methylidene]-substituted benzohydrazide (11a–i) were prepared by the reaction of 2-chloroquinoline-3-carbaldehyde (2) and an acid hydrazide (10a–i). The synthesized compounds were characterized by IR, NMR, Mass spectrometry, elemental analysis and screened for their antibacterial (serial dilution technique and disc diffusion method) and anticancer activity by NCI 60 cell screen at a single high dose (10−5 M) on various panel/cell lines. The synthesized compounds (8a, 8c, 12a, 12b, 12c and 12h) were acting as a magic bullet against gram-positive strains of Bacillus cereus MTCC1305, and the compounds (12a, 12c and 12h) were also found to be extremely active against Klebsiella pneumonia NCTC7447. In the in vitro screen on tested cancer cell line, the compound (12d) showed 95.70 growth percent (GP) and highly active on SNB-75 (CNS cancer) and UO-31 (renal cancer) (GP = 53.35 and 64.35, respectively), and the compound (8a) showed 96.86 GP and highly active on SNB-75 (CNS cancer GP 51.27).