Ethyl (2S)-(+)-2-[4-(6-chlorobenzoxazol-2-yloxy)phenoxy]propanoate

A resistant biotype of Peldon A1 of Alopecurus myosuroides shows moderately enhanced metabolism of 14C-fenoxaprop ethyl. However, in the more resistant Lincs. E1, the metabolism rates of fenoxaprop ethyl are intermediate between Peldon A1 and the susceptible Rothamsted biotype. Fenoxaprop ethyl is hydrolyzed to the corresponding propionic acid which undergoes further degradation to give polar metabolites. The amounts of the metabolites depend on the metabolism activity of the individual biotypes. By wheat, barley, and crabgrass plants, fenoxaprop ethyl is de-esterified to fenoxaprop, resulting in a phytotoxic-free acid, 6-chloro-2,3-dihydrobenzoxazol-2-one, and 4-hydroxyphenoxypropionic acid.