2400. Clopyralid

Nomenclature

CAS number: 1702-17-6
3,6-Dichloro-2-pyridinecarboxylic acid; 3,6-dichloropicolinic acid; 3,6-DCP; Dowco 290.
C6H3Cl2NO2; mol wt 192.00.
C 37.53%, H 1.57%, Cl 36.93%, N 7.30%, O 16.67%.

Description and references

Systemic post-emergence herbicide for use in food crops and mesquite. Prepn: H. Johnston, BE 644105; idem, US 3317549 (1964, 1967 both to Dow). Alternate process: S. D. McGregor, US 4087431 (1978 to Dow). Physicochemical properties, toxicity and herbicidal activity: J. G. Brown, S. D. Uprichard, Proc. Br. Crop Prot. Conf. - Weeds 1976, 119. GLC determn: A. J. Pik, G. W. Hodgson, J. Assoc. Off. Anal. Chem. 59, 264 (1976). Persistence in soil: A. J. Pik et al., J. Agric. Food Chem. 25, 1054 (1977). Field trial in mesquite control: R. W. Bovey, R. E. Meyer, Weed Sci. 33, 349 (1985).

Chemical structure

Properties

White, odorless crystalline solid, mp 151-152°. Vapor pressure at 25°: 1.2×10-5 mm Hg. Soly at 25°: ≈1000 ppm in water, >25% w/w in methanol, acetone, xylene. LD50 in male, female rats (mg/kg): >5000, 4300 orally; LC50 (96 hr) to rainbow trout: 103.5 mg/l (Brown, Uprichard).

Derivative

Monoethanolamine salt.

Nomenclature

CAS number: 57754-85-5
Dow Shield (Dow AgroSci.); Lontrel (Dow AgroSci.); Reclaim (Dow AgroSci.); Stinger (Dow AgroSci.); Transline (Dow AgroSci.).
C6H3Cl2NO2.C2H7NO; mol wt 253.08.
C 37.97%, H 3.98%, Cl 28.02%, N 11.07%, O 18.97%.

Use

Herbicide.