Acifluorfen

Last updated
Acifluorfen
Acifluorfen structure.svg
Acifluorfen molecule spacefill.png
Names
Preferred IUPAC name
5-[2-Chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid
Identifiers
  • Compounds
  • Acid: Acifluorfen
  • Na+ salt: Acifluorfen sodium
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.051.468 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/C14H7ClF3NO5/c15-10-5-7(14(16,17)18)1-4-12(10)24-8-2-3-11(19(22)23)9(6-8)13(20)21/h1-6H,(H,20,21) Yes check.svgY
    Key: NUFNQYOELLVIPL-UHFFFAOYSA-N Yes check.svgY
  • Na+ salt:InChI=1S/C14H7ClF3NO5.Na/c15-10-5-7(14(16,17)18)1-4-12(10)24-8-2-3-11(19(22)23)9(6-8)13(20)21;/h1-6H,(H,20,21);/q;+1/p-1
    Key: RVULBHWZFCBODE-UHFFFAOYSA-M
  • Acid:Clc2cc(ccc2Oc1cc(C(=O)O)c([N+]([O-])=O)cc1)C(F)(F)F
Properties [1]
C14H7ClF3NO5
Molar mass 361.66 g·mol−1
Density 1.573 g/mL
Melting point 155 °C
250 g/L (20 °C)
log P 1.18 (20 °C)
Acidity (pKa)3.86
Pharmacology
Legal status
  • AU: S6 (Poison)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Acifluorfen is the ISO common name [2] for an organic compound used as an herbicide. It acts by inhibiting the enzyme protoporphyrinogen oxidase which is necessary for chlorophyll synthesis. Soybeans naturally have a high tolerance to acifluorfen and its salts, via metabolic disposal by glutathione S-transferase. [3] [4] It is effective against broadleaf weeds and grasses and is used agriculturally on fields growing soybeans, peanuts, peas, and rice. [5]

Contents

History

The nitrophenyl ethers are a well-known class of herbicides, the oldest member of which was nitrofen, invented by Rohm & Haas and first registered for sale in 1964. [6] This area of chemistry became very competitive, with the Mobil Oil Corporation's filing in 1969 and grant in 1974 of a patent to the structural analog with a COOCH3 group adjacent to the nitro group of nitrofen. [7] This product, bifenox, was launched with the brand name Mowdown in 1981. Meanwhile Rohm & Haas introduced acifluorfen (as its sodium salt with brand name Blazer) in 1980, having developed it under the code number RH-6201. [8] It had much improved properties including a wider spectrum of herbicidal effect and good safety to soybean crops. The first patent for the material was published in December 1975, [9] although an earlier Belgian patent published in September 1973 had described related chemistry. [10]

Synthesis

The preparation of acifluorfen first described in the Rohm & Haas patent includes as its final steps an Ullmann condensation between 2-chloro-4-trifluoromethylphenol and 2-nitro-5-fluorobenzonitrile. The intermediate is then hydrolysed using hydrobromic acid in acetic acid as solvent. [9]

Acifluorfen synthesis.svg

Mechanism of action

The detailed mechanism of action for nitrofen, acifluorfen and related diphenyl ether herbicides such as fomesafen was unknown at the time they were invented. The effects visible on whole plants are chlorosis and desiccation: several hypotheses were advanced regarding the molecular-level interactions which might explain these symptoms. [11] The now-accepted explanation for the damage is that these compounds inhibit the enzyme protoporphyrinogen oxidase, which leads to an accumulation of protoporphyrin IX in the plant cells. This is a potent photosensitizer which activates oxygen, leading to lipid peroxidation. Both light and oxygen are required for this process to kill the plant. [12] [13]

Usage

In the United States, the Environmental Protection Agency (EPA) is responsible for regulating pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the Food Quality Protection Act (FQPA) and the Pesticide Registration Improvement Act (PRIA). [14] A pesticide can only be used legally according to the directions on the label that is included at the time of the sale of the pesticide. The purpose of the label is "to provide clear directions for effective product performance while minimizing risks to human health and the environment". A label is a legally binding document that mandates how the pesticide can and must be used and failure to follow the label as written when using the pesticide is a federal offence. [4] [15]

Acifluorfen sodium is normally applied postemergence (when weeds are visible in the crop). It controls or suppresses broadleaf weeds, grasses and sedges and is effective on a very wide range of species including Abutilon theophrasti , Acalypha ostryifolia , Acanthospermum hispidum , Amaranthus palmeri , Ambrosia artemisiifolia , Anoda cristata , Barbarea vulgaris , Brassica kaber , Calystegia sepium , Cannabis sativa , Cardiospermum halicacabum , Cassia obtusifolia , Chenopodium album , Citrullus lanatus , Convolvulus arvensis , Croton glandulosus , Cyperus esculentus , Datura stramonium , Digitaria , Echinochloa crus-galli , Eleusine indica , Euphorbia heterophylla , Helianthus annuus , Hibiscus trionum , Ipomoea quamoclit , Melochia corchorifolia , Mollugo verticillata , Polygonum convolvulus , Portulaca oleracea , Richardia scabra , Sesbania exaltata , Setaria faberi , Solanum rostratum , Sorghum halepense , Striga asiatica and Xanthium strumarium . The product is typically used at application rates of 0.375 lb a.i. per acre. [15]

The estimated annual use of acifluorfen in US agriculture is mapped by the US Geological Service and shows that as of 2018 approximately 550,000 pounds (250,000 kg) were applied — mainly in soybean. [16] The compound is not registered for use in the European Union, although a closely related nitrophenyl ether, bifenox, is available there. [17]

Safety

In California, acifluorfen is listed as "known to the state to cause cancer or reproductive toxicity" according to Proposition 65. [18]

See also

Related Research Articles

<span class="mw-page-title-main">Diquat</span> Chemical compound

Diquat is the ISO common name for an organic dication that, as a salt with counterions such as bromide or chloride is used as a contact herbicide that produces desiccation and defoliation. Diquat is no longer approved for use in the European Union, although its registration in many other countries including the USA is still valid.

<span class="mw-page-title-main">Phenoxy herbicide</span> Class of herbicide

Phenoxy herbicides are two families of chemicals that have been developed as commercially important herbicides, widely used in agriculture. They share the part structure of phenoxyacetic acid.

<span class="mw-page-title-main">Glufosinate</span> Broad-spectrum herbicide

Glufosinate is a naturally occurring broad-spectrum herbicide produced by several species of Streptomyces soil bacteria. Glufosinate is a non-selective, contact herbicide, with some systemic action. Plants may also metabolize bialaphos and phosalacine, other naturally occurring herbicides, directly into glufosinate. The compound irreversibly inhibits glutamine synthetase, an enzyme necessary for the production of glutamine and for ammonia detoxification, giving it antibacterial, antifungal and herbicidal properties. Application of glufosinate to plants leads to reduced glutamine and elevated ammonia levels in tissues, halting photosynthesis and resulting in plant death.

<span class="mw-page-title-main">Protoporphyrinogen oxidase</span>

Protoporphyrinogen oxidase or protox is an enzyme that in humans is encoded by the PPOX gene.

<span class="mw-page-title-main">Sulfentrazone</span> Chemical compound

Sulfentrazone is the ISO common name for an organic compound used as a broad-spectrum herbicide. It acts by inhibiting the enzyme protoporphyrinogen oxidase. It was first marketed in the US in 1997 by FMC Corporation with the brand name Authority.

<span class="mw-page-title-main">Propanil</span> Chemical compound

Propanil is a widely used contact herbicide. With an estimated use of about 8 million pounds in 2001, it is one of the more widely used herbicides in the United States. Propanil is said to be in use in approximately 400,000 acres of rice production each year.

<span class="mw-page-title-main">Saflufenacil</span> Chemical compound

Saflufenacil is the ISO common name for an organic compound of the pyrimidinedione chemical class used as an herbicide. It acts by inhibiting the enzyme protoporphyrinogen oxidase to control broadleaf weeds in crops including soybeans and corn.

<span class="mw-page-title-main">Lactofen</span> Chemical compound

Lactofen is a complex ester of acifluorfen and is a nitrophenyl ether selective herbicide and fungicide. It is used in postemergence applications to certain crops which are resistant to its action. The name "Lactofen" is approved by the American National Standards Institute and the Weed Science Society of America, and is also approved in China (乳氟禾草灵).

<span class="mw-page-title-main">Mesotrione</span> Chemical compound used as an herbicide

Mesotrione is the ISO common name for an organic compound that is used as a selective herbicide, especially in maize. A synthetic inspired by the natural substance leptospermone, it inhibits the enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD) and is sold under brand names including Callisto and Tenacity. It was first marketed by Syngenta in 2001.

<span class="mw-page-title-main">Nitrofen</span> Chemical compound

Nitrofen is an herbicide of the diphenyl ether class. Because of concerns about its carcinogenicity, the use of nitrofen has been banned in the European Union and in the United States since 1996. It has been superseded by related protoporphyrinogen oxidase enzyme inhibitors including acifluorfen and fomesafen.

4-Hydroxyphenylpyruvate dioxygenase (HPPD) inhibitors are a class of herbicides that prevent growth in plants by blocking 4-Hydroxyphenylpyruvate dioxygenase, an enzyme in plants that breaks down the amino acid tyrosine into molecules that are then used by plants to create other molecules that plants need. This process of breakdown, or catabolism, and making new molecules from the results, or biosynthesis, is something all living things do. HPPD inhibitors were first brought to market in 1980, although their mechanism of action was not understood until the late 1990s. They were originally used primarily in Japan in rice production, but since the late 1990s have been used in Europe and North America for corn, soybeans, and cereals, and since the 2000s have become more important as weeds have become resistant to glyphosate and other herbicides. Genetically modified crops are under development that include resistance to HPPD inhibitors. There is a pharmaceutical drug on the market, nitisinone, that was originally under development as an herbicide as a member of this class, and is used to treat an orphan disease, type I tyrosinemia.

<span class="mw-page-title-main">Quinclorac</span> Herbicide, synthetix auxin

Quinclorac is a selective herbicide used primarily to control weeds in rice crops, but is also used on other agricultural crops and is found in some household herbicides for lawn use. Most lawn maintenance companies use the product for the control of annual grass weeds like crabgrass.

<span class="mw-page-title-main">Bifenox</span> Chemical compound

Bifenox is the ISO common name for an organic compound used as an herbicide. It acts by inhibiting the enzyme protoporphyrinogen oxidase which is necessary for chlorophyll synthesis.

<i>Monsanto Co. v. Rohm and Haas Co.</i>

Monsanto Co. v. Rohm and Haas Co., 456 F.2d 592, is a 1972 decision of the United States Court of Appeals for the Third Circuit interpreting what conduct amounts to fraudulent procurement of a patent.

<span class="mw-page-title-main">Fomesafen</span> PPOi herbicide

Fomesafen is the ISO common name for an organic compound used as an herbicide. It acts by inhibiting the enzyme protoporphyrinogen oxidase (PPO) which is necessary for chlorophyll synthesis. Soybeans naturally have a high tolerance to fomesafen, via metabolic disposal by glutathione S-transferase. As a result, soy is the most common crop treated with fomesafen, followed by other beans and a few other crop types. It is not safe for maize/corn or other Poaceae.

<span class="mw-page-title-main">Fluazifop</span> ACCase herbicide, fop, anti-grass

Fluazifop is the common name used by the ISO for an organic compound that is used as a selective herbicide. The active ingredient is the 2R enantiomer at its chiral centre and this material is known as fluazifop-P when used in that form. More commonly, it is sold as its butyl ester, fluazifop-P butyl with the brand name Fusilade.

<span class="mw-page-title-main">Indaziflam</span> Preemergent herbicide discovered in 2009

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<span class="mw-page-title-main">Butafenacil</span> Chemical compound

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<span class="mw-page-title-main">Aclonifen</span> Chemical compound

Aclonifen is a diphenyl ether herbicide which has been used in agriculture since the 1980s. Its mode of action has been uncertain, with evidence suggesting it might interfere with carotenoid biosynthesis or inhibit the enzyme protoporphyrinogen oxidase (PPO). Both mechanisms could result in the observed whole-plant effect of bleaching and the compound includes chemical features that are known to result in PPO effects, as seen with acifluorfen, for example. In 2020, further research revealed that aclonifen has a different and novel mode of action, targeting solanesyl diphosphate synthase which would also cause bleaching.

<span class="mw-page-title-main">Chlorsulfuron</span> ALS inhibitor herbicide

Chlorsulfuron is an ALS inhibitor herbicide, and is a sulfonylurea compound. It was discovered by George Levitt in February 1976 while working at DuPont, which was the patent assignee.

References

  1. Pesticide Properties Database. "Acifluorfen". University of Hertfordshire. Retrieved 2021-03-03.
  2. "Compendium of Pesticide Common Names: acifluorfen". BCPC.
  3. Andrews, Christopher J.; Skipsey, Mark; Townson, Jane K.; Morris, Carol; Jepson, Ian; Edwards, Robert (1997). "Glutathione transferase activities toward herbicides used selectively in soybean". Pesticide Science . Wiley. 51 (2): 213–222. doi:10.1002/(sici)1096-9063(199710)51:2<213::aid-ps622>3.0.co;2-l. ISSN   0031-613X.
  4. 1 2 "Registration Review Label Mitigation for Sodium Acifluorfen" (PDF). United States Environmental Protection Agency . 2020-06-02. Retrieved 2021-03-05.
  5. Acifluorfen, Extension Toxicology Network
  6. Pesticide Properties Database. "Nitrofen". University of Hertfordshire. Retrieved 2021-03-03.
  7. USpatent 3784635,Theissen R.J.,"Herbicidal 4-trifluoromethyl-4'-nitrodiphenyl ethers",issued 1974-01-08, assigned to Mobil Oil Corporation
  8. Pesticide Properties Database. "Acifluorfen-sodium". University of Hertfordshire. Retrieved 2021-03-03.
  9. 1 2 USpatent 3928416,Bayer H. O.; Swithenbank C.& Yih R. Y.,"Herbicidal 4-trifluoromethyl-4'-nitrodiphenyl ethers",issued 1975-12-23, assigned to Rohm & Haas
  10. BEpatent 796677,Bayer H. O.; Swithenbank C.& Yih R. Y.,"Nouveaux ethers 4-trifluoromethyl-4'-nitro-diphenyliques herbicides et leur application a la lutte contre les mauvaises herbes",issued 1973-09-13, assigned to Rohm & Haas
  11. Ridley, Stuart M. (1983). "Interaction of Chloroplasts with Inhibitors". Plant Physiology. 72 (2): 461–468. doi:10.1104/pp.72.2.461. PMC   1066256 . PMID   16663025.
  12. Dayan, Franck E.; Reddy, Krishna N.; Duke, Stephen O. (1999). "Structure-Activity Relationships of Diphenyl Ethers and Other Oxygen-Bridged Protoporphyrinogen Oxidase Inhibitors". Peroxidizing Herbicides. pp. 141–161. doi:10.1007/978-3-642-58633-0_5. ISBN   978-3-642-63674-5.
  13. Nagano, Eiki (1999). "Herbicidal Efficacy of Protoporphyrinogen Oxidase Inhibitors". Peroxidizing Herbicides. pp. 293–302. doi:10.1007/978-3-642-58633-0_11. ISBN   978-3-642-63674-5.
  14. "About Pesticide Registration". US EPA. 27 February 2013. Retrieved 2021-02-27.
  15. 1 2 United Phosphorus, Inc (2012). "Ultra Blazer herbicide" (PDF). Retrieved 2021-03-06.
  16. US Geological Survey (2021-10-12). "Estimated Agricultural Use for Acifluorfen, 2018" . Retrieved 2023-12-13.
  17. Pesticide Properties Database. "Bifenox". University of Hertfordshire. Retrieved 2021-03-03.
  18. The Proposition 65 List