5912. Mesotrione

Nomenclature

CAS number: 104206-82-8
2-[4-(Methylsulfonyl)-2-nitrobenzoyl]-1,3-cyclohexanedione; ZA-1296; Callisto (Syngenta).
C14H13NO7S; mol wt 339.32.
C 49.55%, H 3.86%, N 4.13%, O 33.01%, S 9.45%.

Description and references

Triketone herbicide for use in maize; inhibits p-hydroxyphenylpyruvate dioxygenase (HPPD). Synthetic mimic of leptospermone, a natural herbicide produced by the bottlebrush plant, Callistemon citrinus Stapf. Prepn: C. G. Carter, EP 186118 (1986 to Stauffer); idem, US 5006158 (1991 to ICI). Comprehensive description: R. A. Wichert et al., Brighton Crop Prot. Conf. - Weeds 1999, 105-110. HPLC determn in crops, soil, water: P. Alferness, L. Wiebe, J. Agric. Food Chem. 50, 3926 (2002). Adsorption and degradation in soil: J. S. Dyson et al., J. Environ. Qual. 31, 613 (2002). Review: G. Mitchell et al., Pest Manage. Sci. 57, 120-128 (2001).

Chemical structure

Properties

Opaque solid, mp 165°. pKa (20°): 3.12. Vapor pressure (20°): 4.27 × 108 mm Hg. Soly in water at 20° (g/l): 2.2 (pH 4.8); 15 (pH 6.9); 22 (pH 9). LD50 in rats (mg/kg): >5000 orally; >2000 dermally. LC50 in rats (mg/l): >5 by inhalation. LC50 (96 hr) in bluegill sunfish, rainbow trout (mg/l): >120, >120 (Wichert).

Use

Herbicide.