Broad-spectrum grass and broad-leaved weed control in maize and sugar cane. Applied pre-emergence or pre-plant; the spectrum can be enhanced by mixture with other active ingredients.
Common name isoxaflutole
IUPAC name 5-cyclopropyl-1,2-oxazol-4-yl α,α,α-trifluoro-2-mesyl-p-tolyl ketone; 5-cyclopropyl-4-[2-methylsulfonyl-4-(trifluoromethyl)benzoyl]isoxazole
Chemical Abstracts name (5-cyclopropyl-4-isoxazolyl)[2-(methylsulfonyl)-4 (trifluoromethyl)phenyl] methanone
CAS RN [141112–29–0]
PHYSICAL CHEMISTRY
Mol. wt. 359.3 M.f. C15H12F3NO4S Form Off-white or pale yellow solid. M.p. 140 °C V.p. 1 × 10-3 mPa (25 °C) Kow logP = 2.34 S.g./density 1.42 (20 °C) Solubility In water 6.2 mg/l (pH 5.5, 20 °C). In acetone 293, dichloromethane 346, ethyl acetate 142, n-hexane 0.10, toluene 31.2, methanol 13.8 (all in g/l, 20 °C). Stability Stable to heat (14 d at 54 °C) and to light. Hydrolysis DT50 11 d (pH 5), 20 h (pH 7), 3 h (pH 9). Aqueous photolysis DT50 40 h.
APPLICATIONS
Biochemistry Rapidly metabolised in plants, and in the soil, by opening of the isoxazole ring, to form a diketonitrile, which is the active species (K. E. Pallett et al., Pest Manag. Sci., 2001, 57, 133, and refs. therein); this is a p-hydroxyphenyl pyruvate dioxygenase inhibitor. This enzyme converts p-hydroxyphenyl pyruvate to homogentisate, a key step in plastoquinone biosynthesis. Inhibition leads to indirect inhibition of carotenoid biosynthesis, giving rise to chlorosis of new growth.
Mode of action Systemic by either root or foliar uptake.
Uses Broad-spectrum grass and broad-leaved weed control in maize and sugar cane. Applied at 75–140 g/ha pre-emergence or pre-plant; the spectrum can be enhanced by mixture with other active ingredients.
Formulation types SC; WG; WP.