Description
Tefuryltrione (TFT) is a b-triketone herbicide that causes weed whitening and death by inhibiting HPPD (hydroxyphenylpyruvate dioxygenase) activity. It is the first registered herbicide for rice farming. Triketone herbicides, including TFT, are becoming popular, replacing sulfonylurea herbicides because of their herbicidal activity against resistant weeds. In Japan, TFT was registered in 2007 and has been increasingly used in rice farming since then. TFT was also registered in 2015 in Korea. TFT is included in 21 commercial pesticide products, all of which are primarily used in rice farming. Of these 21 products, 3 contain TFT as the single active ingredient. The 18 products are multi-component mixtures containing TFT and other active ingredients: 6 products contain oxaziclomefone, 3 contain pyraclonil, 3 contain pyraclonil and metazosulfuron, 3 contain fentrazamide, and 3 contain mefenacet[1].
Definition
ChEBI: 2-{2-chloro-4-(methylsulfonyl)-3-[(tetrahydrofuran-2-ylmethoxy)methyl]benzoyl}cyclohexane-1,3-dione is a beta-triketone that is 2-benzoylcyclohexane-1,3-dione in which the benzoyl group is substituted at positions 2, 3, and 4 by chlorine, (tetrahydrofuran-2-ylmethoxy)methyl, and methylsulfonyl groups, respectively. It is a sulfone, a member of monochlorobenzenes, an ether, an aromatic ketone, a member of cyclohexanones, a member of oxolanes and a beta-triketone.
Synthesis
3.55 g of methyl 2-chloro-4-(methylsulfonyl)-3-(((tetrahydrofuran-2-yl)methoxy)methyl)benzoate and 1.25 g of 1,3-cyclohexanedione into a reaction flask, add 12.5 mL of acetonitrile as a solvent, stir to dissolve, and add 4.25 mL of ethylenediamine to condense at room temperature for 1.5 h. After the reaction, the enol ester is formed, 2.5 mL of acetonitrile is added as a rearrangement catalyst, and 2 mL of ethylenediamine, and the reaction is stirred at room temperature for 2 h to make the enol product fullyConversion to a keto product. After the completion of the reaction, 40 mL of water was added, the mixture was stirred for 30 minutes, and then the mixture was allowed to stand for separation. The organic layer was evaporated to remove the solvent and then recrystallized from methanol, filtered, and dried to give tefuryltrione, which was calculated to have a yield of 90.5%.
Environmental Fate
Tembotrione and tefuryltrione have been increasingly used in rice farming. In surface water and groundwater, such herbicides were detected frequently due to excessive and frequent use. It is worth noting that sulcotrione, tembotrione, and tefuryltrione are easily transformed into xanthenediones that are more toxic than the parent compounds. Tefuryltrione was frequently detected in surface water in rice fields at concentrations up to 1.9 μg L?1 [1]. Residues of triketone herbicides and metabolites in water could potentially affect non-target organisms, such as reducing the nonspecific esterase activity of Tetrahymena pyriformis and the metabolic activity of vibrio fischeri.
References
[1] Motoyuki Kamata, Yoshihiko Matsui, Mari Asami . “Presence of the β-triketone herbicide tefuryltrione in drinking water sources and its degradation product in drinking waters.” Chemosphere 178 (2017): Pages 333-339.
[2] Xiaofei Wang. “Photocatalysis of the Triketone Herbicide Tembotrione in Water with Bismuth Oxychloride Nanoplates: Reactive Species, Kinetics and Pathways.” Journal of Environmental Chemical Engineering (2022).
