To evaluate antibacterial activity of a series of molecules bearing 1,3,4-oxadiazole and azomethine moieties.
The 4-chlorobenzoic acid (1
) was precursor to N'-substituted-2-
, through a multistep synthesis of corresponding ester, 2, hydrazide, 3 and 1,3,4-oxadiazole, 4.
The molecule, 4
, was subjected to electrophilic substitution by ethyl-2-bromoacetate to yield 5
which was stepped to 2-(5-(4-chlorophenyl)-1,3,4-oxadiazol-2-ylthio)acetohydrazide (6
). The target molecules, 8a-p, were synthesized by nucleophilic addition of 6 to arylaldehydes, 7a-p
. The proposed structures of all the synthesized molecules were elucidated by Infra Red (IR), Proton Nuclear Magnetic Resonance (1
H-NMR) and Electron Impact Mass Spectrometry (EI-MS) spectral data. Antibacterial activity was evaluated by the principle that microbial growth is in a log
phase of growth and so results in increased absorbance of broth medium which is observed.
The molecule, 8b
, was active against S. aureus
and 8c against S. typhi
only. The molecule, 8p, was the most active against S. typhi
with minimum inhibitory concentration (MIC) value of 10.04 ± 1.25 μM while 8e
was active against E. coli with MIC of 9.45 ± 1.00 μM, both relative to the reference standard, ciprofloxacin, which displayed MIC of 9.13 ± 2.00 and 8.90 ± 1.65 μM, respectively.
Most of the synthesized molecules exhibit 50 % antibacterial activity relative to the reference. Molecules 8b
are the least active compounds