Metsulfuron-methyl 95% TC

Metsulfuron-methylHerbicideHRAC B WSSA 2; sulfonylureaNOMENCLATUREChemical Abstracts name methyl 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]benzoateCAS RN [74223-64-6]PHYSICAL CHEMISTRYMol. wt. 381.4M.f. C14H15N5O6SForm Colourless crystals; (tech., off-white solid, with a faint ester-like odour).M.p. 158 ºCV.p. 3.3 ´ 10-7mPa (25 ºC)KOWlogP = -1.74 (pH 7)Henry 2.3 ´ 10-10Pa m3mol-1(calc.)S.g./density 1.47Solubility In water 0.55 (pH 5), 2.79 (pH 7), 213 (pH 9) (all in g/l, 25 ºC). In hexane 0.00079, xylene 0.58, ethanol 2.3, methanol 7.3, acetone 36, dichloromethane 121 (all in g/l, 20 ºC).Stability Stable in air up to c. 140 ºC. Hydrolysis DT50(25 °C), 22 d (pH 5), stable (pH 7 and 9).pKa 3.3APPLICATIONSBiochemistry 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 derives from rapid metabolism in the crop. Metabolic basis of selectivity in sulfonylureas reviewed (M. K. Koeppe & H. M. Brown, Agro-Food-Industry, 6, 9-14 (1995)).Mode of action Selective systemic herbicide absorbed through the roots and foliage, with rapid translocation both acropetally and basipetally. Susceptible plants cease growth almost immediately after post-emergence treatment, and are killed in 7-21 days. Surfactants increase the activity of metsulfuron-methyl on certain broad-leaved weeds.