【Chemical name】4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one

【Molecular weight】214.3
【Molecular formular】C₈H₁₄N₄OS

【Molecular structure】

【Mode of action】Selective systemic herbicide, absorbed predominantly by the roots, but also by the leaves, with translocation acropetally in the xylem.
【Uses】Pre- and post-emergence control of many grasses and broad-leaved weeds in soya beans, potatoes, tomatoes, sugar cane, alfalfa, asparagus, maize and cereals, at 0.07-1.45 kg/ha. Phytotoxicity Phytotoxic to many crops, including crucifers, cucurbits, lettuce, onions, sugar beet, sunflowers, flax, strawberries, sweet potatoes, and tobacco.
【Physical chemistry】 Form White crystals, with a weak characteristic odour. M.p. 126 °C B.p. 132 °C/2 Pa. V.p. 0.058 mPa (20 °C) K_ow logP = 1.6 (pH 5.6, 20 °C) Henry 1 × 10^-5 Pa m³ mol^-1 (20 °C, calc.) S.g./density 1.26 (20 °C)
Solubility In water 1.05 g/l (20 °C). In dimethyl sulfoxide, acetone, ethyl acetate, dichloromethane, acetonitrile, isopropanol, polyethyleneglycol >250, benzene 220, xylene 60, n-octanol 54 (all in g/l, 20 °C). Stability Relatively stable to u.v. irradiation. At 20 °C, stable to dilute acids and alkalis; DT₅₀ (37 °C) 6.7 h (pH 1.2); DT₅₀ (70 °C) 569 h (pH 4), 47 d (pH 7), 191 h (pH 9). Photodecomposition in water is very rapid (DT₅₀ <1 d). On soil surfaces under natural light conditions, DT₅₀ 14-25 d.

【Mmmalian toxicology】 Oral Acute oral LD₅₀ for male rats 510, female rats 322, mice c. 700, guinea pigs c. 250, cats >500 mg/kg. Skin and eye Acute percutaneous LD₅₀ for rats >20 000 mg/kg. Not irritating to skin and eyes (rabbits). Inhalation LC₅₀ (4 h) for rats >0.65 mg/l air (dust). NOEL (2 y) for rats and dogs 100, mice c. 800 mg/kg diet. ADI 0.013 mg/kg b.w. Toxicity Class  WHO (a.i.) II; EPA (formulation) III EC classification Xn; R22| N; R50, R53 (also draft concn. dep. assignments)

【Ecotoxicology】Birds Acute oral LD₅₀ for bobwhite quail 164, mallard ducks 460-680 mg/kg. Fish LC₅₀ (96 h) for rainbow trout 74.6, golden orfe 141.6, sheepshead minnows 85 mg/l. Daphnia LC₅₀ (48 h) 49.6 mg/l. Algae E_rC₅₀ for Scenedesmus subspicatus 0.021 mg/l. Bees Not toxic to bees; LD₅₀ 35 μg/bee. Worms LC₅₀ for Eisenia foetida 331.8 mg/kg dry soil.