Synthesis and Herbicidal Activity of (3,5-Dinitrophenyl)-4-(benzyloxymethyl)oxazole Derivatives

A series of novel (3,5-dinitrophenyl)-4-(benzyloxymethyl)oxazole derivatives was designed, synthesized and characterized by 1H, 13C NMR and HRMS data. The spatial structure of 4-[(2-chlorophenoxy)methyl]-2-(3,5-dinitrophenyl)oxazole was determined by single crystal X-ray diffraction method. Herbicidal activity of the target compounds was evaluated using Echinochloa crusgalli, Lolium perenne, Lactuca sativa, and Medicago sativa as tested species. According to the experimental results, most compounds demonstrated good pre-emergence herbicidal activity. 4-[(3-Bromo-5-chlorophenoxy)methyl]-2-(3,5-dinitrophenyl)oxazole exhibited relatively better pre-emergence efficacy against the four tested weeds when considering the overall control effect. It reveals that 4-[(3-bromo-5-chlorophenoxy)methyl]-2-(3,5-dinitrophenyl)oxazole could serve as a pre-emergence herbicide lead, and the need for further structural optimization and adjustment of the herbicide.