ethyl (RS)-2-chloro-3-[2-chloro-5-(4-difluoromethyl-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl)-4-fluorophenyl]propionate

a,2-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-fluorobenzenepropanoate 

C₁₅H₁₄Cl₂F₃N₃O₃

Viscous yellow liquid.

-22.1 ℃

350-355℃ /760 mmHg

1.6 ×10-2 mPa (25 ℃)

>110 ℃

1.457 (20 ℃)

In water 12 ug/ml (20 ℃), 22 ug/ml (25 ℃), 23 ug/ml (30 ℃). In toluene 0.9, hexane 0.03 (both in g/ml, 20 ℃); miscible with acetone, ethanol, ethyl acetate and dichloromethane.

Hydrolytic DT₅₀ 3.6 h (pH 9), 8.6 d (pH 7), stable (pH 5). Aqueous photolytic DT₅₀ 8 d.

Acts by inhibition of protoporphyrinogen oxidase, leading to membrane disruption.

Absorbed by foliage, with limited translocation.

Post-emergence control in cereals of a wide range of broad-leaved weeds, especially Galium aparine, Abutilon theophrasti, Ipomoea hederacea var. hederacea, Chenopodium album and several mustard species, at 9-35 g/ha. Also for desiccation of potatoes, at 60 g/ha

Good tolerance in wheat, barley and rice.

Acute oral LD₅₀ for female rats 5143 mg/kg.

Acute percutaneous LD₅₀ for rats >4000 mg/kg. Minimally irritating to eyes and non-irritating to skin (rabbits). No skin sensitisation (guinea pigs)

LC₅₀ (4 h) for rats >5 mg/l.

(2 y) for rats 3 mg/kg daily.

0.03 mg/kg (proposed).

WHO (a.i.) III (company classification); EPA (formulation) III, IV

LD₅₀ for quail >1000 mg/kg. LC₅₀ for quail and ducks >5000 ppm.

LC₅₀ (96 h) 1.6-43 mg/l, depending on species.

EC₅₀ (48 h) 9.8 mg/l.

 EC₅₀ 12-18 ug/l, depending on species.

LC₅₀ >820 mg/kg soil.

Rapidly converted to the free acid, which is hydroxylated and then oxidised at the triazolinone methyl to form the dibasic acid; DT₅₀ (carfentrazone-ethyl) <7 d, DT₅₀ (carfentrazone) <28 d.

In rats, c. 80% of the administered dose is rapidly absorbed and excreted in the urine within 24 h. The major metabolite was the corresponding acid. Further metabolism appears to involve oxidative hydroxylation of the methyl group or dehydrochlorination to form the corresponding cinnamic acid.

Broken down in the soil by microbial action; not susceptible to photodecomposition nor volatility following soil application. Strongly adsorbed to sterile soils. In non-sterile soils, rapidly converted to the free acid, which has low soil binding.  In the laboratory, soil DT₅₀ is a few hours, degrading to the free acid, which in turn has DT₅₀ 2.5-4.0 d.