TECHNICAL --- HERBICIDE: Metsulfuron-methyl

CAS No.: 74223-64-6
Content: 95%TC

NOMENCLATURE
metsulfuron-methyl
Chemical Abstracts name: methyl
2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]benzoate
CAS RN: [74223-64-6]
metsulfuron
Common name:
metsulfuron (BSI, WSSA, ANSI, draft E-ISO, (m) draft F-ISO)
IUPAC name:
2-(4-methoxy-6-methyl-1,3,5-triazin-2-ylcarbamoylsulfamoyl)benzoic acid
Chemical Abstracts name:
2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]benzoic acid
CAS RN: [79510-48-8]

PHYSICAL CHEMISTRY
metsulfuron-methyl
Mol. wt.: 381.4
M.f.: C₁₄H₁₅N₅O₆S
Form: Colourless crystals; (tech., off-white solid, with a faint ester-like odour).
M.p.: 158 篊
V.p.: 3.310^-7 mPa (25 篊)
KOW: logP = -1.74 (pH 7)
Henry: 2.310^-10 Pa m³ mol^-1 (calc.)
S.g./density: 1.47
Solubility: In water 0.55 (pH 5), 2.79 (pH 7), 213 (pH 9) (all in g/l, 25 篊). In hexane 0.00079, xylene 0.58, ethanol 2.3, methanol 7.3, acetone 36, dichloromethane 121 (all in g/l, 20 篊).
Stability: Stable in air up to c. 140 篊. Hydrolysis DT₅₀ (25 癈), 22 d (pH 5), stable (pH 7 and 9).
pKa: 3.3
metsulfuron
Mol. wt.: 367.3 M.f.: C₁₃H₁₃N₅O₆S Form: Solid.

APPLICATIONS
metsulfuron-methyl
Biochemistry: 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.
Uses: Metsulfuron-methyl controls a wide range of annual and perennial broad-leaved weeds in wheat, barley, rice and oats, by either pre- or post-emergence application, at 4-7.5 g/ha post-emergence.