ISSN 2995-9246
International Journal of Chemistry | Vol. 1, No. 5, May 2010 | pp. 35–42
DOI: 10.46882/2010/IJC/000005
Article Type: Original Research Paper
Title: Microwave-Assisted Synthesis and Antibacterial Evaluation of Novel Sulfonamide Derivatives Bearing a Schiff Base Moiety
Names of Authors: Marcus A. Gomez¹, Blessing C. Umeh², Tariq M. Al-Alawi³
Authors’ Affiliations:
¹Department of Chemistry, University of Cape Town, Cape Town, South Africa
²Department of Pharmaceutical Chemistry, University of Benin, Benin City, Nigeria
³Department of Chemistry, College of Science, Sultan Qaboos University, Muscat, Oman
Abstract: The development of novel antimicrobial agents is imperative due to the rapid global rise of multi-drug resistant bacterial pathogens. A series of novel sulfonamide derivatives containing a Schiff base core (compounds 4a–4j) were synthesized via an efficient, rapid microwave-assisted condensation reaction of sulfanilamide with various substituted aromatic aldehydes. Compared to conventional heating methods, the microwave-assisted protocol reduced reaction times from 4.5 hours to 6–10 minutes and enhanced product yields from 62% to a range of 88%–95%. The molecular structures of all newly synthesized compounds were validated using elemental analysis, FTIR, 1H-NMR, and 13C-NMR spectroscopy. The in vitro antibacterial activities of the compounds were screened against two Gram-positive strains (Subtilis bacillus, Staphylococcus aureus) and two Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa) utilizing the broth microdilution method to determine Minimum Inhibitory Concentrations (MIC). Compound 4d, possessing a nitro group substitution at the para-position of the aromatic ring, exhibited the most potent antibacterial action, with an MIC value of 7.8 micro-g/mL against S. aureus and 15.6 micro-g/mL against E. coli, matching the efficacy of the standard reference drug Ciprofloxacin.
Keywords: Microwave synthesis, Sulfonamides, Schiff base, Antibacterial activity, Minimum Inhibitory Concentration
Manuscript Timeline: Received: February 14, 2010; Revised: March 20, 2010; Accepted: April 14, 2010; Published: May 06, 2010