Epyrifenacil

Epyrifenacil
Names
Preferred IUPAC name
Ethyl 2-[[3-[2-chloro-4-fluoro-5-[3-methyl-2,6-dioxo-4-(trifluoromethyl)pyrimidin-1-yl]phenoxy]-2-pyridinyl]oxy]acetate
Identifiers
3D model (JSmol)
ChEBI
EC Number
  • 885-819-9
UNII
  • InChI=1S/C21H16ClF4N3O6/c1-3-33-18(31)10-34-19-14(5-4-6-27-19)35-15-8-13(12(23)7-11(15)22)29-17(30)9-16(21(24,25)26)28(2)20(29)32/h4-9H,3,10H2,1-2H3
    Key: XPEVJXBWHXAUDR-UHFFFAOYSA-N
  • CCOC(=O)COC1=C(C=CC=N1)OC2=C(C=C(C(=C2)N3C(=O)C=C(N(C3=O)C)C(F)(F)F)F)Cl
Properties
C21H16ClF4N3O6
Molar mass 517.82 g·mol−1
Hazards
GHS labelling:
GHS09: Environmental hazard
Warning
H410
P273, P391, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Epyrifenacil is an herbicide from the pyrimidinedione class which acts as a protoporphyrinogen oxidase inhibitor. It is effective against grass weeds and some broadleaf weeds. and is used for pre-plant burndown on canola, field corn, soybean, and wheat fields, and for non-agricultural use on non-crop areas such as areas around industrial or farm buildings.

Mode of Action

Epyrifenacil inhibits the enzyme protoporphyrinogen oxidase, which is involved in the biosynthesis of chlorophyll and heme.

Health and Safety

Epyrifenacil is hepatotoxic and carcinogenic in animal models, but these effects are not considered likely to affect humans at relevant exposure levels.

One of the major products of the environmental degradation of epyrifenacil is the PFAS-type groundwater pollutant trifluoroacetic acid.

Regulation

The U.S. EPA approved epyrifenacil as a new ingredient on June 30, 2026.

It has not yet been approved in the EU.

See also

References

  1. 1 2 Sada Y, Jin Y, Hikosaka M, Ido K (2025). "Epyrifenacil, a new systemic PPO-inhibiting herbicide for broad-spectrum weed control". Pest Management Science. 81 (5): 2463–2468. doi:10.1002/ps.8244. PMC 11981982. PMID 38873996.
  2. ↑ "EPA Announces Proposed Registration of Herbicide Epyrifenacil". U.S. EPA. November 3, 2025. Retrieved 2 July 2026.
  3. 1 2 3 "Trump EPA Approves Two More 'Forever Chemical' Pesticides for Use on Most Widely Grown U.S. Crops". The Center for Biological Diversity. June 30, 2026. Retrieved 2 July 2026.
  4. ↑ Matsunaga K, Abe J, Ogata K, Fukunaga S, Kitamoto S (2021). "Elucidation of the species differences of epyrifenacil-induced hepatotoxicity between mice and humans by mass spectrometry imaging analysis in chimeric mice with humanized liver". The Journal of Toxicological Sciences. 46 (12): 601–609. doi:10.2131/jts.46.601. PMID 34853245.
  5. ↑ Fukunaga S, Ogata K, Eguchi A, Matsunaga K, Sakurai K, Abe J, et al. (December 2022). "Evaluation of the mode of action and human relevance of liver tumors in male mice treated with epyrifenacil". Regulatory Toxicology and Pharmacology. 136 105268. doi:10.1016/j.yrtph.2022.105268. PMID 36210011.
  6. ↑ Sakurai K, Abe J, Hirasawa K, Takeuchi H, Kitamoto S (2021). "Absorption, Distribution, Metabolism, and Excretion of a New Herbicide, Epyrifenacil, in Rats". Journal of Agricultural and Food Chemistry. 69 (44): 13190–13199. Bibcode:2021JAFC...6913190S. doi:10.1021/acs.jafc.1c04167. PMID 34723485.
  7. ↑ "EPN Urges EPA to Halt Epyrifenacil Registration, Citing Deficient Risk Review". environmentalprotectionnetwork.org. December 3, 2025.
  8. ↑ Messina E (June 30, 2026). "Memorandum Supporting Final Decision to Approve Registration for the New Active Ingredient Epyrifenacil". U,S. EPA. Retrieved 2 July 2026.