Flufenacet

Last updated
Flufenacet
Flufenacet.svg
Names
Preferred IUPAC name
N-(4-Fluorophenyl)-N-(propan-2-yl)-2-{[5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl]oxy}acetamide
Other names
Fluthiamide; Thiafluamide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.127.787 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/C14H13F4N3O2S/c1-8(2)21(10-5-3-9(15)4-6-10)11(22)7-23-13-20-19-12(24-13)14(16,17)18/h3-6,8H,7H2,1-2H3
    Key: IANUJLZYFUDJIH-UHFFFAOYSA-N
  • InChI=1/C14H13F4N3O2S/c1-8(2)21(10-5-3-9(15)4-6-10)11(22)7-23-13-20-19-12(24-13)14(16,17)18/h3-6,8H,7H2,1-2H3
    Key: IANUJLZYFUDJIH-UHFFFAOYAX
  • CC(C)N(c1ccc(cc1)F)C(=O)COc2nnc(s2)C(F)(F)F
Properties
C14H13F4N3O2S
Molar mass 363.33 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Flufenacet is an oxyacetanilide herbicide applied before crops have emerged. [1] It was registered for use in the United States in 1998 and the European Union in 2004. [2]

Contents

Mode of action

Flufenacet is related to the chloroacetamide class of herbicides and has the same mode of action through inhibiting the germination of seeds by inhibiting very long chain fatty acid synthesis. [3] [4]

In the model plant Arabidopsis thaliana it causes similar symptoms to the fiddlehead mutant. [5]

Usage

Flufenacet usage in England Flufenacet england usage.svg
Flufenacet usage in England

In temperate Europe, flufenacet is commonly used in cereal crops to control grass weeds such as black-grass (Alopecurus myosuroides) that have evolved resistance to other herbicides and is applied in combination with other herbicides including pendimethalin, diflufenican, flurtamone, metribuzin and aclonifen. [6] As of 2019 in the United Kingdom, resistance to flufenacet had began to be found in black-grass and rye-grass. [7] As of 2022 it was the most widely applied herbicide and third most widely applied pesticide in England, being used on 2.9 million hectares. [8]

Environmental fate

Map of the estimated use of the herbicide flufenacet in the United States in 2018 and graph showing annual use since 1992 Flufenacet USA 2018.png
Map of the estimated use of the herbicide flufenacet in the United States in 2018 and graph showing annual use since 1992

Flufenacet and its metabolites can be classified as PFAS substances, or so-called "forever chemicals". They break down to produce trifluoroacetic acid (TFA), a persistent substance that pollutes groundwater. [9] [10]

Toxicity

In September 2024, the European Food Safety Authority has concluded that flufenacet is an endocrine disruptor of humans and wild mammals via the thyroid (T)-modality. [9] The active substance falls under the exclusion criteria of the Plant Protection Products Regulation. Re-authorisation of the active substance by the EU Commission is therefore no longer possible. The EU Commission will draw up a proposal for the non-authorisation of flufenacet, including withdrawal and sunset periods, which the EU member states are expected to vote on in spring 2025. [11] [12]

Synthesis

Flufenacet can be obtained by reacting equivalent amounts of 2-methylsulfonyl-5-trifluoromethyl-1,3,4-thiadiazole with 2-hydroxy[N-(4-fluoropheny)-N-isopropyl]acetamide in the presence of sodium hydroxide in acetone. [13]

Synthesis Fluenacet synthesis.svg
Synthesis

References

  1. ↑ Rouchaud, J.; Neus, O.; Eelen, H.; Bulcke, R. (2001). "Persistence, Mobility, and Adsorption of the Herbicide Flufenacet in the Soil of Winter Wheat Crops". Bulletin of Environmental Contamination and Toxicology . 67 (4): 609–616. Bibcode:2001BuECT..67..609R. doi:10.1007/s001280167. PMID   11779079. S2CID   8544255.
  2. ↑ "Flufenacet (Ref: FOE 5043)". PPDB: Pesticide Properties DataBase. University of Hertfordshire.
  3. ↑ "Chloroacetamide Mode of Action, I: Inhibition of Very Long Chain Fatty Acid Synthesis in Scenedesmus acutus". Zeitschrift für Naturforschung C. 53 (11–12): 995–1003. 1 December 1998. doi:10.1515/znc-1998-11-1210.
  4. ↑ Matthes, Bernd; Schmalfuß, Jochen; Böger, Peter (1 December 1998). "Chloroacetamide Mode of Action, II: Inhibition of Very Long Chain Fatty Acid Synthesis in Higher Plants". Zeitschrift für Naturforschung C. 53 (11–12): 1004–1011. doi:10.1515/znc-1998-11-1211.
  5. ↑ Lechelt-Kunze, C.; Meissner, R. C.; Drewes, M.; Tietjen, K. (2003). "Flufenacet herbicide treatment phenocopies the fiddlehead mutant in Arabidopsis thaliana". Pest Management Science . 59 (8): 847–856. doi: 10.1002/ps.714 . PMID   12916765.
  6. ↑ Dücker, Rebecka; Zöllner, Peter; Parcharidou, Evlampia; Ries, Susanne; Lorentz, Lothar; Beffa, Roland (November 2019). "Enhanced metabolism causes reduced flufenacet sensitivity in black‐grass (Alopecurus myosuroides Huds.) field populations". Pest Management Science. 75 (11): 2996–3004. doi:10.1002/ps.5414.
  7. ↑ Impey, Louise (12 July 2019). "How to get effective weed control when using flufenacet". Farmers Weekly. Retrieved 23 February 2025.
  8. ↑ "PESTICIDE USAGE SURVEY REPORT 309". Pusstats. FERA. Retrieved 23 February 2025.
  9. 1 2 Arp, Hans Peter H.; Gredelj, Andrea; Glüge, Juliane; Scheringer, Martin; Cousins, Ian T. (12 November 2024). "The Global Threat from the Irreversible Accumulation of Trifluoroacetic Acid (TFA)". Environmental Science & Technology . 58 (45): 19925–19935. doi:10.1021/acs.est.4c06189. PMC   11562725 .
  10. ↑ European Food Safety Authority (September 2024). "Peer review of the pesticide risk assessment of the active substance flufenacet". EFSA Journal. 22 (9). doi:10.2903/j.efsa.2024.8997. PMC   11427894 .
  11. ↑ Bockholt, Karl (2024-10-02). "Schlag ins Kontor: Behörde streicht wichtigen Wirkstoff gegen Unkraut". agrarheute.com (in German). Retrieved 2025-02-23.
  12. ↑ "Pflanzenschutz. Es ist soweit: auch Flufenacet fällt weg". DLG-Mitteilungen (in German). 2024-09-27. Retrieved 2025-02-23.
  13. ↑ Hatzios KK, ed; Herbicide Handbook of the Weed Science Society of America. 7th ed. Suppl. Champaign, IL: Weed Sci Soc Amer, S. 9 (1998).
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