Chlorsulfuron is an ALS (acetolactate synthase) inhibitor herbicide, and is a sulfonylurea compound.[3][4] It was discovered by George Levitt in February 1976 while working at DuPont, which was the patent assignee.[5][6][7]

Chlorsulfuron
Names
Preferred IUPAC name
2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbamoyl]benzene-1-sulfonamide
Other names
DPX4189
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.059.316 Edit this at Wikidata
EC Number
  • 265-268-5
KEGG
UNII
UN number 3077 2588
  • InChI=1S/C12H12ClN5O4S/c1-7-14-10(17-12(15-7)22-2)16-11(19)18-23(20,21)9-6-4-3-5-8(9)13/h3-6H,1-2H3,(H2,14,15,16,17,18,19) checkY
    Key: VJYIFXVZLXQVHO-UHFFFAOYSA-N checkY
  • O=C(NC1=NC(=NC(=N1)C)OC)NS(=O)(=O)C=2C=CC=CC2Cl
Properties[1]
C12H12ClN5O4S
Molar mass 357.78
Appearance White crystalline solid
Density 1.48 g/cm3
Melting point 173 °C (343 °F; 446 K)
12500 mg/L (20 °C)
log P -0.99
Acidity (pKa) 3.4
Hazards[2]
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).

Brand names

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Originally introduced in 1982 under the brand name Glean by DuPont,[1][7] later also as Telar,[3] in North America.

Chemistry

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The first synthesis of chlorsulfuron was disclosed in a patent filed by the American chemical company DuPont in 1977. 2-Chlorobenzenesulfonyl isocyanate was condensed with 2-amino-4-methoxy-6-methyl-1,3,5-triazine to form the sulfonylurea product.[6]

 

Mode of action

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Chlorsulfuron is an herbicide of the acetolactate synthase inhibitor (ALS inhibitor) class, HRAC (Herbicide Resistance Action Committee) group 2[4][3] (legacy HRAC Group B,[4] Australian Group B).[8]

Efficacy

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Triticum aestivum is naturally resistant via aryl hydroxylation then conjugation with glucose compounds into non-herbicidal conjugates.[9] Widespread weed resistance to chlorsulfuron has been found across North America and around the world. T. aestivum's close relative Lolium rigidum was found to be using the same mechanism by Christopher et al 1991 and Cotterman & Saari 1992.[9] A North American population of Stellaria media was found by Hall and Devine 1990 to be resistant by way of an ALS target mutation rather than by improved disposal.[9] Increased P450 activity can also be effective, such as in Alopecurus myosuroides (found by Letouzé and Gasquez 2003), and L. rigidum (by Tardif and Powles 1999).[10] Another such mechanism - the acetolactate synthase target-site mutation Pro-197–Ser - was found by Roux et al 2004 to be accompanied by a 37% recessive fitness cost in a model (Arabidopsis thaliana).[11]

Most varieties of wheat are tolerant to chlorsulfuron even at triple the recommended rate, unlike triple-rate trifluralin and pendimethalin that torpedoed emergence rates across the board, though final crop yields were never as affected as initial emergence. None though significantly affected emergence at normal rates.[12]

Use in genetic engineering

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Genes conveying resistance to chlorsulfuron are used as selectable markers when attempting transformation with other genes,[13][14] for example in Dianthus caryophyllus[13] and Marchantia polymorpha.[14]

Crops have also been deliberately made resistant, for example in maize/corn by McCabe et al 1988 using bombardment with the relevant gene attached to tungsten particles.[15]

Applications

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US Geological Survey estimate of chlorsulfuron use in the USA to 2017

Chlorsulfuron has a broad spectrum of activity on commercially important broadleaf weeds and grasses but at the recommended use rate it is safe to important crops such as wheat. Its properties mean that it can be applied to soil so emerging weeds take it up and are controlled. Alternatively, spraying after weeds are already present in the crop will also lead to control. The product is used at application rates of 0.008–0.0155 pounds per acre (9.0–17.4 g/ha).[16] The estimated use in US agriculture is mapped by the US Geological Service and shows that from 1992 to 2017, the latest date for which figures are available, up to 120,000 pounds (54,000 kg) were applied each year. The compound is used mainly in wheat but also in pasture.[17]

Chlorsulfuron is recommended alone or with aminocyclopyrachlor for control of Centaurea solstitialis, Centaurea calcitrapa, and Centaurea iberica in the Pacific Northwest of North America.[3]

References

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  1. ^ a b Pesticide Properties Database. "Chlorsulfuron". University of Hertfordshire.
  2. ^ PubChem Database. "Chlorsulfuron".
  3. ^ a b c d "Starthistle, yellow (Centaurea solstitialis), purple (Centaurea calcitrapa), and Iberian (Centaurea iberica)". Pacific Northwest Pest Management Handbooks. Pacific Northwest Extension (Oregon, Washington, Idaho). 2015-11-10. Retrieved 2021-03-03.
  4. ^ a b c "HRAC MOA 2020 Revision Description and Master Herbicide List". Herbicide Resistance Action Committee. 2020-09-14. Retrieved 2021-04-01.
  5. ^ DE 2715786, George Levitt, "Herbicidal sulfonamides", issued 1977, assigned to E. I. du Pont de Nemours and Company 
  6. ^ a b US 4127405, George Levitt, "Herbicidal sulfonamides", issued 1978, assigned to E. I. du Pont de Nemours and Company 
  7. ^ a b Bhardwaj, Gaurab (2007). "From Pioneering Invention to Sustained Innovation: The Story of Sulfonylurea Herbicides" (PDF). Chemical Heritage NewsMagazine. 25 (1). Archived from the original (PDF) on 2006-11-18.
  8. ^ "2024 HRAC GLOBAL HERBICIDE MOA CLASSIFICATION MASTER LIST". Herbicide Resistance Action Committee.
  9. ^ a b c Holt, Jodie S.; Powles, Steven B.; Holtum, Joseph A. M. (1993). "Mechanisms and Agronomic Aspects of Herbicide Resistance". Annual Review of Plant Physiology and Plant Molecular Biology. 44 (1). Annual Reviews: 203–229. doi:10.1146/annurev.pp.44.060193.001223. ISSN 1040-2519.
  10. ^ Powles, Stephen B.; Yu, Qin (2010-06-02). "Evolution in Action: Plants Resistant to Herbicides". Annual Review of Plant Biology. 61 (1). Annual Reviews: 317–347. doi:10.1146/annurev-arplant-042809-112119. ISSN 1543-5008. PMID 20192743.
  11. ^ Vila-Aiub, M M; Neve, P; Roux, F (2011-05-04). "A unified approach to the estimation and interpretation of resistance costs in plants". Heredity. 107 (5). The Genetics Society (Nature): 386–394. doi:10.1038/hdy.2011.29. ISSN 0018-067X. PMC 3199924. PMID 21540885.
  12. ^ Lemerle, D.; Leys, A.R.; Hinkley, R.B.; Fisher, J.A. (1985). "Tolerances of wheat cultivars to pre-emergence herbicides". Australian Journal of Experimental Agriculture. 25 (4): 922. doi:10.1071/EA9850922.
  13. ^ a b Tanaka, Yoshikazu; Brugliera, Filippa (2013-02-19). "Flower colour and cytochromes P450". Philosophical Transactions of the Royal Society B: Biological Sciences. 368 (1612). The Royal Society: 20120432. doi:10.1098/rstb.2012.0432. ISSN 0962-8436. PMC 3538422. PMID 23297355.
  14. ^ a b Kohchi, Takayuki; Yamato, Katsuyuki T.; Ishizaki, Kimitsune; Yamaoka, Shohei; Nishihama, Ryuichi (2021-06-17). "Development and Molecular Genetics of Marchantia polymorpha". Annual Review of Plant Biology. 72 (1). Annual Reviews: 677–702. doi:10.1146/annurev-arplant-082520-094256. ISSN 1543-5008. PMID 33684298. S2CID 232159593.
  15. ^ Klein, Theodore M.; Arentzen, Rene; Lewis, Paul A.; Fitzpatrick-McElligott, Sandra (1992). "Transformation of Microbes, Plants and Animals by Particle Bombardment". Nature Biotechnology. 10 (3). Nature Portfolio: 286–291. doi:10.1038/nbt0392-286. ISSN 1087-0156. PMID 1368100. S2CID 26707595.
  16. ^ FMC Corporation (2019). "Glean XP herbicide US label" (PDF).
  17. ^ US Geological Survey. "Estimated Agricultural Use for chlorsulfuron, 2017". Retrieved 2021-09-28.