Design, synthesis and biological activities of novel 5-isopropyl-2-methylphenolhydrazide-based sulfonamide derivatives

Sulfonamides have enormous importance in biological sciences. In the present investigation, the fundamental energetic group, hydrazide-based sulfonamide, has been incorporated into a naturally occurring phenolic monoterpenoid, carvacrol (5-isopropyl-2-methylphenol) moiety, with the aim of combining the active groups in order to generate more potent antimicrobial and anti-oxidant agents. Series of hydrazide-based sulfonamide derivatives (IV a-g) have been synthesized and characterized by modern sophisticated techniques such as H-1 NMR, C-13 NMR and LC-MS. The newly synthesized derivatives were screened for their antimicrobial activities against three fungal (Aspergillus niger, A. flavus and A. fumigatus) and three bacterial (Escherichia coli, Staphylococcus aureus and Bacillus subtilis) species, of which compounds IVc and IVd were found to have good antifungal activity and compounds IVd and IVg exhibited decent antibacterial activities. antioxidant activity was performed by DPPH radical scavenging assay. Compound IVd has been found to be more active in comparison to standard ascorbic acid and compounds IVa, IVb, and IVc demonstrated excellent antioxidant activity.