Synthsis and Herbicidal Activity of N-(7-Fluoro-3-oxo-3,4-dihydro-2H-benzo[b]oxazin-6-yl) Acetamide

In search of safe and more efficacious herbicidal compounds,nine novel derivatives of N-7-fluoro-3-oxo-3,4-dihydro-2H-benzo[b] oxazin-6-yl acetamide were prepared from the reaction of 2-substitued acetyl chloride with the corresponding 2H benzooxazine-3-one.Their chemical structures were confirmed by elemental analysis,IR and ~1H NMR.The primary bioassay results showed that 5d exhibited control efficacy of more than 90% againstAmaranthus spinosus at 75 g a.i./hm~2.