Indolyl‐4H‐Chromene Derivatives as Antibacterial Agents: Synthesis, in Vitro and in Silico Studies

Abstract

In this study, indolyl‐4H‐chromene derivatives are designed and synthesised using an eco‐friendly multicomponent one‐pot synthesis using benzaldehydes, nitroketene N, S‐acetals, and indoles combine with InCl3, a Lewis acid catalyst, and ethanol, an environmentally acceptable solvent. Due to antibiotic resistance, assessed these Indolyl‐4H‐chromene derivatives for their in vitro antibacterial activity against Gram‐positive and Gram‐negative bacteria, including Streptococcus pyogenes, Staphylococcus aureus, Clostridium pyrogenes, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa, using the agar well diffusion method and Minimum Inhibition Concentration (MIC) assay. Three compounds, 4‐(1H‐indol‐3‐yl)‐6‐methoxy‐N‐methyl‐3‐nitro‐4H‐chromen‐2‐amine, 4‐(1H‐indol‐3‐yl)‐3‐nitro‐N‐phenyl‐4H‐chromen‐2‐amine and 4‐(6‐Fluoro‐1H‐Indol‐3‐yl)‐N‐methyl‐3‐nitro‐4H‐chromen‐2‐amine showed better zone of inhibition (mm) and Minimum Inhibition Concentration (MIC) values of 10 μg/mL to 25 μg/mL against all bacterial types. The Ki values of 278.60 nM and 2.21 nM for compound 4‐(1H‐indol‐3‐yl)‐3‐nitro‐N‐phenyl‐4H‐chromen‐2‐amine showed improved interactions with DNA gyrase B and topoIV ParE′s ATP binding sites in in silico studies.