Synthesis, characterization and antibacterial activity of 2-[1-(5-chloro-2-methoxy-phenyl)-5-methyl-1H-pyrazol-4-yl]-5-(substituted-phenyl)-[1,3,4]oxadiazoles.
In the present investigation a series of novel 2-[1-(5-chloro-2-methoxy-phenyl)-5-methyl-1H-pyrazol-4-yl]-5-(substituted-phenyl)-[1,3,4]oxadiazoles (4a-j) were synthesized by cyclization of substituted-benzoic acid N'-[1-(5-chloro-2-methoxy-phenyl)-5-methyl-1H-pyrazole-4-carbonyl]-hydrazide by using phosphorousoxychloride at 120 degrees C. The chemical structure of the newly synthesized compounds was characterized by analytical and spectral (IR, (1)H NMR, (13)C NMR and LC-MS) methods. The title compounds were screened for qualitative (zone of inhibition) and quantitative antibacterial activity (MIC) by agar cup plate and microtitration methods, respectively. Among the synthesized compounds in this series compound 2-[1-(5-chloro-2-methoxyphenyl)-5-methyl-1H-pyrazol-4-yl]-5-(4-fluorophenyl)-1,3,4-oxadiazole (4b) was found to exhibit significant antibacterial activity with MICs of 22.4, 29.8, 29.6 and 30.0 microg/mL against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae, respectively. The other compounds exhibited moderate activity when compared to standard substance Ampicillin.
Rai
Neithnadka Premsai
NP
Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India.
Narayanaswamy
Venugopala Katharigatta
VK
Shashikanth
Sheena
S
Arunachalam
Pirama Nayagam
PN
D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects; D007711:Klebsiella pneumoniae / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D010069:Oxadiazoles / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects; D013329:Structure-Activity Relationship
D000900:Anti-Bacterial Agents; D010069:Oxadiazoles