S Rasool1,
Aziz-ur-Rehman 1,
MA Abbasi1,
S Gul1,
MN Akhtar2,
I Ahmad3,
S Afzal3
1Department of Chemistry, Government College University, Lahore-54000, Pakistan;
2Faculty of Industrial Sciences & Technology (FIST), University Malaysia Pahang (UMP), Lebuhraya Tun Razak 26300 Gambang, Kuantan, Malaysia;
3Department of Pharmacy, The Islamia University of Bahawalpur, Bahawalpur-63100, Pakistan.
For correspondence:- Aziz-ur-Rehman
Email:
Received: 24 May 2014
Accepted: 12 April 2015
Published: 29 June 2015
Citation:
Rasool S, A, Abbasi M, Gul S, Akhtar M, Ahmad I, et al.
Synthesis of N'-substituted-2-(5-(4-chlorophenyl)-1,3,4-oxadiazol-2-ylthio)acetohydrazide derivatives as suitable antibacterial agents. Trop J Pharm Res 2015; 14(6):1081-1088
doi:
10.4314/tjpr.v14i6.21
© 2015 The authors.
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Abstract
Purpose: To evaluate antibacterial activity of a series of molecules bearing 1,3,4-oxadiazole and azomethine moieties.
Methods: The 4-chlorobenzoic acid (1) was precursor to N'-substituted-2-(5-(4-chlorophenyl)-1,3,4-oxadiazol-2-ylthio)acetohydrazide, 8a-p, 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 (1H-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.
Results: 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.
Conclusion: Most of the synthesized molecules exhibit 50 % antibacterial activity relative to the reference. Molecules 8b and 8c are the least active compounds.
Keywords: 1,3,4-Oxadiazole, 4-Chlorobenzoic acid, Antibacterial activity, Azomethine