Flutolanil

Genotoxicity

In the presence and absence of metabolic activation, flutolanil (100-250000 mg/mL) was not mutagenic in the Ames Test in Salmonella typhimurium and Escherichia coli strains and was negative in a forward mutation assay at the thymidine kinase locus in mouse lymphoma cells at concentrations of 6-100 mg/mL. Flutolanil (1000-500000 mg/mL) did not induce DNA damage in Bacillus subtilis strains or increase chromosomal aberrations in human lymphocytes, in the presence and absence of metabolic activation, at concentrations up to 1000 mg/mL. However, at 48.5 mg/mL, flutolanil induced chromosomal aberrations in cultured Chinese hamster lung cells in the presence of metabolic activation, although this effect was relatively weak. No effect was observed in the absence of metabolic activation. Using cultured rat hepatocytes in vitro, unscheduled DNA synthesis was not induced by flutolanil at concentrations up to 80 mg/mL. In an in vivo study, flutolanil was not genotoxic in the micronucleus assay in mouse bone marrow cells after single oral doses of 6400, 8000 and 10000 mg/kg bw or after repeat doses at 10000 mg/kg bw/day.

Uses

Flutolanil is a fungicide that has been used for controlling brown patch on creeping bentgrass fairways.

Uses

Flutolanil is used to control Basidiomycetes diseases in rice, cereals, sugar beet and other crops.

Uses

Agricultural fungicide.

Application

Flutolanil 40SC Fungicide is a systemic fungicide for control of Basidiomycete diseases on turf. This product has shown excellent safety on Kentucky bluegrass, annual bluegrass, annual and perennial ryegrass, red fescue, tall fescue, bentgrass, Bermudagrass, zoysiagrass, and St. Augustine grass. Flutolanil 40SC Fungicide may be tank mixed with other labeled fungicides.

Definition

ChEBI: Flutolanil is a member of the class of benzamides, obtained by formal condensation of the carboxy group of 2-(trifluoromethyl)benzoic acid with the amino group of 3-(ispropyloxy)aniline. A fungicide used to control a range of pathogens especially Rhizoctonia spp. on rice, turf and other crops. It has a role as an EC 1.3.5.1 [succinate dehydrogenase (quinone)] inhibitor and an antifungal agrochemical. It is a member of benzamides, an aromatic ether, a member of (trifluoromethyl)benzenes and a benzanilide fungicide.

Trade name

MONCUT

Safety Profile

Low toxicity by ingestion, skincontact, intraperitoneal, and subcutaneous routes. Whenheated to decomposition it emits toxic vapors of NOx andF??.

Metabolic pathway

Flutolanil is an analogue of mepronil in which the methyl group is replaced by trifluoromethyl. Both compounds have systemic activity. This change in structure should render flutolanil more biostable by hindering hydrolysis and removing the option of methyl hydroxylation and further oxidation. This seems to be borne out in practice in that most of the metabolism of flutolanil occurs via O-dealkylation and aryl hydroxylation. Hydrolysis has not been detected.

Mode of action

Flutolanil is a SDHI (Succinate-dehydrogenase inhibitor) with narrow spectrum. Flutolanil has inhibitory effect against development of each step of the infection cycle. Inhibition of invasion from sclerotium and mycelial growth result in preventive and curative effect in infection, respectively。

Degradation

Flutolanil is a stable arylamide with no particularly weak link in its comparatively simple chemistry. It is stable over the pH range 3-11 and it is stable to heat (PM). It is stable in sunlight (PM) but it was slowly degraded in 50% aqueous ethanol solution irradiated with a high pressure mercury lamp whilst bubbling oxygen through the solution (Tsao and Eto, 1991). The study was conducted using non-radiolabelled compound. No degradation occurred in the absence of oxygen. Even under these conditions, the addition of photosensitisers was required to give a reasonable amount of breakdown. With 5% acetone in the solution, 20% degradation was obtained in 8 hours. Almost no decomposition occurred on a glass surface in 8 hours unless a sensitiser (e.g. benzophenone) was added. This gave 40% decomposition.
The products in solution and on surfaces were different, as shown in Scheme 1. The major product (80%) in solution was 2-(trifluoromethyl)- benzamide (2). The benzoic acid (3) was identified as a minor product. The N-ethoxycarbonyl derivative (4) was due to reaction with the solvent. Amide bond cleavage was postulated to occur via oxidation in the aniline ring (Tsao and Eto, 1991; Yumita et al., 1984). The resulting phenolic products and anilines were converted into unidentified polar polymers.
No product 2 was obtained by irradiation on a glass surface (Tsao and Eto, 1991). Under these conditions 3'-hydroxy-2-(trifluoromethyl)benzanilide (5), i.e. dealkylated flutolanil, and a rearrangement product (6) were the main products. Flutolanil is therefore an extremely stable compound which undergoes slow photo-oxidation rather than aqueous photolysis.