Synthesis And Preliminary Antimicrobial Evaluation Of Schiff Bases Of N -Benzyl Isatin Derivatives

Abstract

Tayseer Hamid Shakir, May Mohammed Jawad Al-Mudhafar

Isatin (1H-indole-2,3-dione) and its analogs are an important class of heterocyclic compounds. N-benzyl isatins and Schiff bases of isatin analogs have been reported to demonstrate a variety of biological activities. This work illustrates the synthesis of new N-benzylisatin Schiff bases and studies their biological activity. Firstly, Isatin and its analogs; 5-methoxyisatin, 5- fluoroisatin reacted with benzyl iodide to obtain N- benzylated derivatives of isatins 2(a-c). Secondly, these compounds were reacted with different amines (sulphanilamide and 4- methyl sulphonyl aniline) separately, to obtain Schiff bases compounds 3(a-c) and 4(a-c), respectively. The synthesized compounds were characterized by using FT-IR and 1HNMR spectroscopy. The synthesized Schiff bases 3(a-c) and 4(a-c) were examined for their in vitro antimicrobial activity using different Gram-positive bacteria, Gram-negative bacteria, and Candida albicans as fungi. The obtained results were compared with standard drugs: amoxicillin, ciprofloxacin, and fluconazole. All the compounds show no antifungal activity at any concentrations used, while most of them show moderate antibacterial activity at concentration 5mg/ mL toward most bacteria except Klebsiella pneumonia.