Common name: Sulfosulfuron

Chemical name:

N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]-2-(ethylsulfonyl)imidazo[1,2-α]pyridine-3-sulfonamide

Structural formula:

Molecular formula: C₁₆H₁₈N₆O₇S₂

Chemical class: Pytimidinysulfonylurea herbicides

CAS No.: 141776-32-1

Properties:

Form: White odorless solid

Melting point: 201.1-201.7℃

Vapour pressure: 8.81×10^-8 mPa (25℃)

Solubility in water: 17.6(pH 5), 1627(pH 7), 482(pH 9)(all in mg/l, 20℃)

Solubility in solvents: In acetone 0.7, methanol 0.33, ethyl acetate 1.01, dichloromethane 4.35, xylene 0.16, heptane 0.01(all in g/l, 20℃)

Stability: Stable＜54℃ for 14d

Toxicity:

Acute oral LD₅₀ for rats: ＞5000mg/kg

Acute dermal LD₅₀ for rats: ＞5000mg/kg

Inhalation for rats LC₅₀: Practically non-toxic

Non-irritating to skin, moderately irritating to eyes.

Ecotoxicology:

Effects on aquatic organisms: rainbow trout＞95mg/l, carp＞91mg/l, bluegill sunlight ＞96mg/l, sheephead minnow 101mg/l (96h), daphnia EC₅₀＞96mg /l(48h)

Effects on bees: LD₅₀(contact)＞30μg/bee, (dietary)＞25μg/bee

Effects on birds: bobwhite quail and mallard ducks LD₅₀＞2250mg/kg

Effects on earthworms: LC₅₀＞848mg/kg

Environmental fate:

The primary degradation pathway in soil is the hydrolytic cleavage of the sulfonylurea linkage to yield the corresponding sulfonamide and dimethoxypyrimidinamine. Photodegradation is also a mode of environmental dissipation.

Mode of action:

Branched chain amino acid synthesis (ALS or AHAS) inhibitor. Acts by inhibiting biosynthesis of the essential amino acid valine and isoleucine, hence stopping cell division and plant growth. Selectivity derives from rapid metabolism in the crop. Metabolic basis of selectivity in sulfonylureas.

Usage:

Demonstrated activity for the control of annual broad-leaved weeds and grass weeds in cereals.