3144. Diflufenican

Nomenclature

CAS number: 83164-33-4
N-(2,4-Difluorophenyl)-2-[3-(trifluoromethyl)phenoxy]-3-pyridinecarboxamide; N-(2,4-difluorophenyl)-2-(3-trifluoromethylphenoxy)nicotinamide; 2′,4′-difluoro-2-(α,α,α-trifluoro-m-tolyloxy)nicotinanilide; M & B 38544; Fenican (Rhone-Poulenc).
C19H11F5N2O2; mol wt 394.29.
C 57.88%, H 2.81%, F 24.09%, N 7.10%, O 8.12%.

Description and references

Pre and post emergence foliar absorbed herbicide for winter weed control in cereal crops; carotenoid biosynthesis inhibitor. Prepn: M. C. Cramp et al., EP 53011; eidem, US 4618366 (1981, 1986 both to May & Baker). Description of physical properties, toxicity and activity: M. C. Cramp et al., Proc. Br. Crop Prot. Conf. - Weeds 1985, 23. Mode of action: G. Britton et al., ibid. 1987, 1015. GC determn in runoff and soil: L. Patty, C. Guyot, Bull. Environ. Contam. Toxicol. 55, 802 (1995). Degradation and persistence in soil: E. Conte et al., J. Agric. Food Chem. 46, 4766 (1998).

Chemical structure

Properties

White crystalline solid, without odor, from toluene, mp 161-162°. Soly at 20°: acetone 10%; acetophenone 5%; aromasol H 1%; cyclohexane 1%; DMF 10%; ethylcellosolve 1%; isophorone 3.5%; kerosene 1%; xylene 2%; water 0.05 mg/l. Vapor pressure at 25°: 4.25 × 10-6 Pa. LD50 in mice, rats (mg/kg): >1000, >2000 orally; in rats (mg/kg): >2000 dermally (Cramp).

Use

Herbicide.