NOMENCLATURE

fenoxaprop-P-ethyl

Chemical Abstracts name ethyl (R)-2-[4-[(6-chloro-2-benzoxazolyl)oxy]phenoxy]propanoate  

CAS RN [71283-80-2]  Development codes Hoe 046360 (Hoechst); AE F046360 (AgrEvo)  

fenoxaprop-P

Common name fenoxaprop-P (BSI, draft E-ISO, (m) draft F-ISO)

IUPAC name (R)-2-[4-(6-chloro-1,3-benzoxazol-2-yloxy)phenoxy]propionic acid; (R)-2-[4-(6-chlorobenzoxazol-2-yloxy)phenoxy]propionic acid  

Chemical Abstracts name (R)-2-[4-[(6-chloro-2-benzoxazolyl)oxy]phenoxy]propanoic acid  

CAS RN [113158-40-0]  Development codes Hoe 088406 (Hoechst); AE F088406 (AgrEvo)  

APPLICATIONS

fenoxaprop-P-ethyl

Biochemistry Fatty acid synthesis inhibition in grasses, by inhibition of acetyl CoA carboxylase (ACCase).  Mode of action Fenoxaprop-P-ethyl is a selective herbicide with contact and systemic action, absorbed principally by the leaves, with translocation both acropetally and basipetally to the roots or rhizomes.  Uses Post-emergence control of annual and perennial grass weeds in potatoes, beans, soya beans, beets, vegetables, peanuts, flax, oilseed rape, and cotton; and (when applied with the herbicide safener mefenpyr-diethyl) annual and perennial grass weeds and wild oats in wheat, rye, triticale and, depending on ratio, in some varieties of barley. Phytotoxicity Non-phytotoxic to broad-leaved crops.  Formulation types EC; EW; SE.

ANALYSIS

Details on hplc method are available from  CropScience.  

MAMMALIAN TOXICOLOGY

fenoxaprop-P-ethyl

Oral Acute oral LD50 for rats 3150-4000, mice >5000 mg/kg.  Skin and eye Acute percutaneous LD50 for rats >2000 mg/kg.  Inhalation LC50 (4 h) for rats >1.224 mg/l air.  NOEL (90 d) for rats 0.75 mg/kg b.w. daily (10 ppm), mice 1.4 mg/kg b.w. daily (10 ppm), dogs 15.9 mg/kg b.w. daily (400 ppm).  

ECOTOXICOLOGY

fenoxaprop-P-ethyl

Birds Acute oral LD50 for bobwhite quail >2000 mg/kg.  Fish LC50 (96 h) for bluegill sunfish 0.58, rainbow trout 0.46 mg/l.  Daphnia LC50 (48 h) 0.56 (pH 8.0-8.4), 2.7 (pH 7.7-7.8) (both mg/l).  Algae LC50 (72 h) for Scenedesmus subspicatus 0.51 mg/l.  Bees LC50 (contact) >300 mg/bee; (feed) >1000 mg/bee.  Worms LC50 (14 d) for Eisenia foetida >1000 mg/kg soil.  

ENVIRONMENTAL FATE

Plants In plants, fenoxaprop-ethyl is metabolised via fenoxaprop to 6-chloro-2,3-dihydrobenzoxazol-2-one.  Soil/Environment In soil, fenoxaprop-ethyl is rapidly hydrolysed to fenoxaprop (A. E. Smith, J. Agric. Food Chem., 1985, 33, 483); DT50 1-10 d.