Aclonifen

Last updated
Aclonifen
Aclonifen.svg
Names
IUPAC name
2-chloro-6-nitro-3-phenoxyaniline
Other names
RPA099795
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.070.619 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 277-704-1
PubChem CID
UNII
  • InChI=1S/C12H9ClN2O3/c13-11-10(18-8-4-2-1-3-5-8)7-6-9(12(11)14)15(16)17/h1-7H,14H2 Yes check.svgY
    Key: DDBMQDADIHOWIC-UHFFFAOYSA-N Yes check.svgY
  • C1=CC=C(C=C1)OC2=C(C(=C(C=C2)[N+](=O)[O-])N)Cl
Properties [1]
C12H9ClN2O3
Molar mass 264.67 g·mol−1
Density 1.46 g/cm3
Melting point 81.2 °C (178.2 °F; 354.3 K)
1.4 mg/L (20 °C)
log P 4.37
Acidity (pKa)-3.15
Pharmacology
Legal status
  • AU: S6 (Poison)
Hazards
GHS labelling: [2]
GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
Warning
H317, H351, H410
P201, P202, P261, P272, P273, P280, P281, P302+P352, P308+P313, P321, P333+P313, P363, P391, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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 (removal of leaf colour) and the compound includes chemical features (a nitro group attached to a diphenyl ether) that are known to result in PPO effects, as seen with acifluorfen, for example. [1] [3] [4] In 2020, further research revealed that aclonifen has a different and novel mode of action, targeting solanesyl diphosphate synthase which would also cause bleaching. [5] [6]

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. [7] 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. [8] This product, bifenox, was launched in 1981. Meanwhile, Rohm & Haas introduced acifluorfen (as its sodium salt) in 1980. [9] It had much improved properties including a wider spectrum of herbicidal effect and good safety to soybean crops. The first patent for this material was published in December 1975, [10]

Celamerck scientists were also working on analogs retaining the 4-nitrodiphenyl ether framework and in 1978 filed a patent of relatively narrow scope which claimed compounds having an amine group adjacent to the nitro substituent and also having an additional chlorine atom between the amine and the oxygen of the diphenyl ether. 2-Chloro-3-phenoxy-6-nitroaniline was described as having selectivity, so that important grass weeds could be controlled within dicot crops and this lack of damage to the crop extended to some cereals. [11] Aclonifen was subsequently developed and marketed by Rhône-Poulenc under the code number RPA099795 and launched in 1983 in Europe. [1] [12]

Synthesis

The synthesis of aclonifen Aclonifen synthesis.svg
The synthesis of aclonifen

The preparation of aclonifen first described in Celamerck patents starts from 2,3,4-trichloronitrobenzene. This is reacted in an autoclave with ammonia in dimethyl sulfoxide. The intermediate aniline is treated with potassium phenolate in an Ullmann ether synthesis using acetonitrile as solvent. [11]

Mechanism of action

The detailed mechanism of action for nitro diphenyl ether herbicides such as acifluorfen was unknown at the time they were invented. The effects visible on whole plants are chlorosis and desiccation: in 1983 several hypotheses were advanced regarding the molecular-level interactions which might explain these symptoms. [13] By 1992, it was becoming clear that most compounds of this class inhibit the enzyme protoporphyrinogen oxidase (PPO), 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. [14] [15] [16]

Aclonifen was shown to be an inhibitor of PPO but in addition had effects on carotenoid synthesis, by inhibition of phytoene desaturase at similar concentrations in vitro. [3] This led to the conclusion that it expressed a dual mode of action. [4] [17] In 2020, further research revealed that it is likely to have a completely different and novel mode of action, targeting solanesyl diphosphate synthase. [5] This has led to its being classified in its own group for the purposes of resistance management. [18]

Uses

Aclonifen is registered for use in the European Union, where a two-tiered approach is used for approval and authorisation. Before a formulated product can be developed for market, the active substance must be approved. Then authorisation for the specific product must be sought from every Member State that the applicant wants to sell it to. Afterwards, there is a monitoring programme to make sure the pesticide residues in food are below the limits set by the European Food Safety Authority. The active ingredient is registered for use against weeds in crops including cereals, potato and sunflower. [1] [19] It is particularly safe to sunflower, owing to the metabolism which occurs in that crop. [20] [21]

Aclonifen is now supplied by Bayer Crop Science under a variety of brand names according to the crop and formulation. For example, Proclus is used in winter wheat and Emerger in potatoes. It is normally applied pre-emergence (before weeds are visible in the crop) and controls or suppresses species including Alopecurus myosuroides , Anthemis cotula , Chenopodium album , Fallopia convolvulus , Galium aparine and Viola arvensis when used at application rates of 600 g a.i. per hectare. [22] [23]

In the UK, following the withdrawal of linuron in 2017, aclonifen began to be used as a pre-emergence herbicide in potatoes. [24]

Related Research Articles

<span class="mw-page-title-main">Herbicide</span> Type of chemical used to kill unwanted plants

Herbicides, also commonly known as weed killers, are substances used to control undesired plants, also known as weeds. Selective herbicides control specific weed species while leaving the desired crop relatively unharmed, while non-selective herbicides (sometimes called total weed killers kill plants indiscriminately. Due to herbicide resistance – a major concern in agriculture – a number of products combine herbicides with different means of action. Integrated pest management may use herbicides alongside other pest control methods.

<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">Acifluorfen</span> Chemical compound

Acifluorfen 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. Soybeans naturally have a high tolerance to acifluorfen and its salts, via metabolic disposal by glutathione S-transferase. It is effective against broadleaf weeds and grasses and is used agriculturally on fields growing soybeans, peanuts, peas, and rice.

<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.

All-trans-nonaprenyl diphosphate synthase is an enzyme with systematic name geranylgeranyl-diphosphate:isopentenyl-diphosphate transtransferase . This enzyme catalyses the following chemical reaction

<span class="mw-page-title-main">Crop desiccation</span>

Pre-harvest crop desiccation refers to the application of an agent to a crop just before harvest to kill the leaves and/or plants so that the crop dries out from environmental conditions, or "dry-down", more quickly and evenly. In agriculture, the term desiccant is applied to an agent that promotes dry down, thus the agents used are not chemical desiccants, rather they are herbicides and/or defoliants used to artificially accelerate the drying of plant tissues. Desiccation of crops through the use of herbicides is practiced worldwide on a variety of food and non-food crops.

<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.

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

Pyroxasulfone is a pre-emergence herbicide that inhibits the production of very long chain fatty acids in plants. The structure of the existing herbicide thiobencarb served as the basis for development but pyroxasulfone requires a lower dose (100–25 g/ha) and is more stable resulting in longer efficacy. As of 2016 it had been registered for use in Japan, Australia, USA, Canada, Saudi Arabia and South Africa and was used on crops including maize, soybean, wheat and cotton. In 2015 it was applied to over 6 million hectares of land. Pyroxasulfone is from a novel chemical class but has a similar mode of action to acetamide herbicides such as metolachlor, acetochlor and dimethenamid. It is mainly used to control annual grasses but is also effective against broadleaf weeds including lambsquarters, pigweed and waterhemp and black nightshade

<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

Indaziflam is a preemergent herbicide especially for grass control in tree and bush crops.

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

Butafenacil 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 and some grass weeds in crops including cereals and canola.

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

Tribenuron in the form of tribenuron-methyl is a sulfonylurea herbicide. Its mode of action is the inhibition of acetolactate synthase, group 2 of the Herbicide Resistance Action Committee's classification scheme.

<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. 1 2 3 4 Pesticide Properties Database. "Aclonifen". University of Hertfordshire.
  2. ↑ PubChem Database. "Aclonifen".
  3. 1 2 Kılınç, Özgür; Reynaud, Stéphane; Perez, Laurent; Tissut, Michel; Ravanel, Patrick (February 2009). "Physiological and biochemical modes of action of the diphenylether aclonifen". Pesticide Biochemistry and Physiology. 93 (2): 65–71. doi:10.1016/j.pestbp.2008.11.008.
  4. 1 2 Dayan, Franck E; Owens, Daniel K; Duke, Stephen O (2012-01-09). "Rationale for a natural products approach to herbicide discovery". Pest Management Science . Society of Chemical Industry (Wiley). 68 (4): 519–528. doi:10.1002/ps.2332. ISSN   1526-498X. PMID   22232033. S2CID   10841777.
  5. 1 2 Kahlau, Sabine; Schröder, Florian; Freigang, Jörg; Laber, Bernd; Lange, Gudrun; Passon, Daniel; Kleeßen, Sabrina; Lohse, Marc; Schulz, Arno; von Koskull-Döring, Pascal; Klie, Sebastian; Gille, Sascha (October 2020). "Aclonifen targets solanesyl diphosphate synthase, representing a novel mode of action for herbicides". Pest Management Science. 76 (10): 3377–3388. doi:10.1002/ps.5781. PMID   32034864. S2CID   211063448.
  6. ↑ Pinho, Bárbara (2021-04-06). "The growing problem of pesticide resistance". Chemistry World.
  7. ↑ Pesticide Properties Database. "Nitrofen". University of Hertfordshire. Retrieved 2021-03-03.
  8. ↑ USpatent 3784635,Theissen R.J.,"Herbicidal 4-trifluoromethyl-4'-nitrodiphenyl ethers",issued 1974-01-08, assigned to Mobil Oil Corporation
  9. ↑ Pesticide Properties Database. "Acifluorfen-sodium". University of Hertfordshire. Retrieved 2021-03-03.
  10. ↑ USpatent 3928416,Bayer H. O.; Swithenbank C.& Yih R. Y.,"Herbicidal 4-trifluoromethyl-4'-nitrodiphenyl ethers",issued 1975-12-23, assigned to Rohm & Haas
  11. 1 2 USpatent 4394159,Buck W.; Linden G.& Lust S.et al.,"2-Chloro-3-(phenoxy or phenylthio)-6-6-nitro-anilines",issued 1981-09-16, assigned to Celamerck GmbH and Co KG
  12. ↑ Matringe, M.; Clair, D.; Scalla, R. (1990). "Effects of peroxidizing herbicides on protoporphyrin IX levels in non-chlorophyllous soybean cell culture". Pesticide Biochemistry and Physiology. 36 (3): 300–307. doi:10.1016/0048-3575(90)90039-5.
  13. ↑ 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.
  14. ↑ Nandihalli, Ujjana B.; Duke, Mary V.; Duke, Stephen O. (1992). "Quantitative structure-activity relationships of protoporphyrinogen oxidase-inhibiting diphenyl ether herbicides". Pesticide Biochemistry and Physiology. 43 (3): 193–211. doi:10.1016/0048-3575(92)90033-V.
  15. ↑ 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.
  16. ↑ 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.
  17. ↑ Kılınç, Özgür Kıvılcım (2015). "The Symptoms of Herbicidal Action: The Case of Aclonifen". Turkish Journal of Agriculture - Food Science and Technology. 3 (6): 472. doi: 10.24925/turjaf.v3i6.472-477.391 .
  18. ↑ Weed Science Society of America (April 2021). "HRAC Mode of Action Updates" (PDF). wssa.net. Retrieved 2021-05-10.
  19. ↑ "Conclusion regarding the peer review of the pesticide risk assessment of the active substance aclonifen". EFSA Journal. 6 (10). 2008. doi: 10.2903/j.efsa.2008.149r .
  20. ↑ Kılınç, Özgür; Grasset, Renaud; Reynaud, Stéphane (June 2011). "The herbicide aclonifen: The complex theoretical bases of sunflower tolerance". Pesticide Biochemistry and Physiology. 100 (2): 193–198. doi:10.1016/j.pestbp.2011.04.001.
  21. ↑ Jursík, M.; Soukup, J.; Holec, J.; Andr, J.; Hamouzová, K. (2016). "Efficacy and selectivity of pre-emergent sunflower herbicides under different soil moisture conditions". Plant Protection Science. 51 (4): 214–222. doi: 10.17221/82/2014-PPS .
  22. ↑ "Proclus". cropscience.bayer.co.uk. 2020. Retrieved 2021-05-10.
  23. ↑ "Emerger". cropscience.bayer.co.uk. 2019. Retrieved 2021-05-10.
  24. ↑ Cunningham, Charlotte (12 April 2019). "New herbicide to help replace linuron". Crop Production Magazine. Retrieved 3 May 2021.
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