Synthesis, Characterization, Herbicidal Activities and In silico Studies of Some Highly Functionalized Oxazolone Derivatives

Abstract

Oxazolones, commonly referred to as azlactones, represent a versatile class of five-membered heterocyclic compounds characterized by the presence of nitrogen and oxygen as heteroatoms. The biological activities of oxazolone are primarily associated with modifications at the C-2 and C-4 positions. These compounds have been widely investigated for their herbicidal properties, which arise from their ability to inhibit specific enzymes essential for plant growth and development, ultimately causing weed suppression and death. A series of highly functionalized oxazolone derivatives were synthesized and characterized using techniques such as ¹H NMR, ¹³C NMR, elemental analysis, FT-IR, and mass spectrometry. Their herbicidal activities were assessed in vitro against sterilized seeds of Raphanus sativus at varying concentrations (25, 50, 75, and 100 ppm). The ligand exhibited a half-maximal inhibitory concentration (IC₅₀) of 61.88 ± 4.71, indicating notably higher pre-emergent herbicidal activity compared to its –methoxy and –nitro analogs, which displayed IC₅₀ values of 67.29 ± 4.71 and 70.03 ± 4.71, respectively. The results demonstrated that the herbicidal performance of the oxazolone derivative was superior to its –nitro and –methoxy counterparts but less effective compared to the standard herbicide pendimethalin. Additionally, in silico studies were conducted using PROTOX-II software and the SwissADME predictor to evaluate toxicity and herbicide-likeness. The compounds exhibited promising results in both in vitro and in silico analyses, highlighting the potential for further modification and exploration of oxazolone derivatives as potent herbicides.