Synthesis, Antioxidant and Bacteriostatic Activities of Pyridone Derivatives Based on Ethyl Maltol

ABSTRACT In order to develop pyridone compounds with good antioxidant ability and bacteriostatic activity, the compounds 3‐(benzyloxy)‐2‐ethyl‐1‐propylpyridin‐4(1 H )‐one ( 5a ) to 3‐(benzyloxy)‐2‐ethyl‐1‐(4‐methylbenzyl)pyridin‐4(1H)‐one ( 5e ) were obtained through two steps reaction. The structures were confirmed using nuclear magnetic resonance ( 1 H‐NMR, 13 C‐NMR), Fourier transform infrared spectrometer (FT‐IR), and high resolution mass spectrometry (HRMS). The antioxidant ability of compounds 5a–5e was identified by using 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and hydroxyl radicals (·OH) methods. Turbidimeter method and mycelial growth rate method were used for the determination of in vitro bacteriostatic activity of compounds 5a–5e against gram‐negative bacteria [ Escherichia coli ( E. coli ), Pseudomonas aeruginosa ( P. aeruginosa )], gram‐positive bacteria [ Bacillus subtilis ( B. subtilis ), Staphylococcus aureus ( S. aureus )], and fungi [ Botrytis cinerea ( B. cinerea )]. The antioxidant results showed that at the concentration of 2 mg/mL, compounds 3‐(benzyloxy)‐2‐ethyl‐1‐(furan‐2‐ylmethyl)pyridin‐4(1H)‐one ( 5c ) and 5e exhibited stronger free radical scavenging ability than ethyl maltol. The bacteriostatic activity results showed that compounds 5a and 5e showed good bacteriostatic activities against S. aureus and B. cinerea . Molecular docking results showed that compounds 5a and 5e inhibit the activity of pyruvate dehydrogenase, thereby achieving bacteriostatic effect. This study not only synthesized novel heterocyclic compounds, but also provided new ideas and references for the development and selection of bacteriostatic agents.