methyl a-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-o-toluate

methyl 2-[[[[[(4,6-dimethoxypyrimidin-2-yl)-amino]carbonyl]amino]sulfonyl]methyl]benzoate

C₁₆H₁₈N₄O₇S

White odourless solid.

185-188 ℃; tech. 179.4 ℃.

2.8 ×10-9 mPa (25 ℃)

1.49 (20 ℃)

In water 2.1 (pH 5), 67 (pH 7), 3100 (pH 9) (all in mg/l, 25 ℃). In acetone 5.10, acetonitrile 3.75, dichloromethane 18.4, ethyl acetate 1.75, n-heptane 3.62 ?10-4, xylene: 0.229 (all in g/l, 20 ℃).

Aqueous solutions are most stable under slightly alkaline conditions (pH 8), and slowly degrade under acidic conditions; DT50 6 d (pH 4), stable (pH 7), 141 d (pH 9) (all 25 ℃)

5.2

Branched chain amino acid synthesis (ALS or AHAS) inhibitor. Acts by inhibiting biosynthesis of the essential amino acids valine and isoleucine, hence stopping cell division and plant growth. Selectivity is due to rapid metabolism in the crop. Metabolic basis of selectivity reviewed (M. K. Koeppe & H. M. Brown, Agro-Food-Industry, 6, 9-14 (1995)).

Selective systemic herbicide, absorbed by the foliage and roots, with rapid translocation to the meristematic tissues.

Selective pre- and post-emergence control of annual and perennial weeds and sedges (e.g. Butomus umbellatus, Scirpus maritimus, Scirpus mucronatus, Alisma plantago-aquatica, Sparganium erectum, Cyperus spp., Typha spp., etc.) in flooded or wetland rice, at 46-60 g/ha.

Acute oral LD50 for rats >5000 mg/kg.

Acute percutaneous LD50 for rabbits >2000 mg/kg. Non-irritant to skin and eyes. Not a skin sensitiser (Buehler method).

LC₅₀ (4 h) for rats 5 mg/l air. .

(1 y) for male dogs 21.4 mg/kg b.w. daily; reproduction (2 generation) NOEL for male rats 20 mg/kg b.w. daily; teratogenicity NOEL for rabbits 300 mg/kg b.w. daily. No developmental toxicity or teratogenicity

0.20 mg/kg. 

WHO (a.i.) U; EPA (formulation) IV.

Acute oral LD₅₀ for mallard ducks >2510 mg/kg. Dietary LC₅₀ (8 d) for bobwhite quail, mallard ducks >5620 mg/l.

LC₅₀ (96 h) for rainbow trout >66, bluegill sunfish >120 mg/l.

LC₅₀ (48 h) >130 mg/l.

EC₅₀ (72 h) for Selenastrum capricornutum 0.020 mg/l.

LC₅₀ >1000 mg/kg soil.

After uptake by rice, converted to a non-herbicidal metabolite.

Almost completely biotransformed and rapidly excreted in urine and faeces of rats and goats.

DT₅₀ (ave.) 88.5 d on Flanagan and Keyport silt loam soils. DT50 in water 16-21 d for Italian soils.

analysis by hplc/ms/ms.