Synthesis and Antimicrobial Evaluation of N,N’-(4-Nitro-1,2-phenylene)diamide Derivatives

doi.org/10.26538/tjnpr/v2i8.3

Abstract

In the search for new antibiotics, 4-nitro-1,2-phenylenediamide analogues were synthesized via nucleophilic addition/elimination reaction of carboxylic acid derivatives with 4-nitro-1,2-phenylenediamine. In vitro antimicrobial assay of the analogues was done using the conventional broth dilution method on seven selected clinical isolates. The results of the zones of inhibition showed that N,N’-(4-nitro-1,2-phenylene)diacetamide (3a) has zones of inhibition ranging from 08 mm to 12 mm while (N,N’-(4-nitro-1,2 phenylene)dibenzamide (3c) has zones of inhibition ranging from 12 mm to 21 mm. N,N’-(4-nitro-1,2-phenylene)bis(2,2,2-trifluoroacetamide) (3d) was the most active against all tested organisms with zones of inhibition ranging from 11 mm in
Pseudomonas aeruginosa to 34 mm in Methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibition concentration (MIC) determination reveals that 3d inhibits the growth of tested microbes at a concentration of 12.5 mg/mL with the exception of Klebsiella pneumonia in which the MIC was 25 mg/mL. The Minimum Bactericidal/Fungicidal Concentration (MBC/MFC) results revealed that 3d has the highest bactericidal effect on Pseudomonas aeruginosa, MRSA and Escherichia coli at a concentration of 12.5 mg/mL and was bacteriostatic/fungistatic against the rest of the organisms. The results observed clearly shows that molecules with electron withdrawing groups demonstrated better antibacterial activity.