Metalaxyl

Last updated
Metalaxyl
Metalaxyl.svg
Metalaxyl 3D BS.png
Names
IUPAC name
Methyl 2-[N-(2,6-dimethylphenyl)(methoxy)acetamido]propanoate
Other names
Methyl N-(2,6-dimethylphenyl)-N-(2-methoxyacetyl)alaninate
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.055.418 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 260-979-7
KEGG
PubChem CID
UNII
  • InChI=1S/C15H21NO4/c1-10-7-6-8-11(2)14(10)16(13(17)9-19-4)12(3)15(18)20-5/h6-8,12H,9H2,1-5H3 Yes check.svgY
    Key: ZQEIXNIJLIKNTD-UHFFFAOYSA-N Yes check.svgY
  • COCC(=O)N(c1c(C)cccc1C)C(C)C(=O)OC
Properties
C15H21NO4
Molar mass 279.33 g/mol
AppearanceFine white powder
Density 1.20g/cm3 at 20 °C
Melting point 71 to 72 °C (160 to 162 °F; 344 to 345 K) [1]
Boiling point 295.9 °C (564.6 °F; 569.0 K) at 760 mm Hg
8,400 mg/L at 22 °C
log P 1.65 (octanol/water) [2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Metalaxyl is an acylalanine fungicide with systemic function. [3] Its chemical name is methyl N-(methoxyacetyl)-N-(2,6-xylyl)-DL-alaninate. It can be used to control Pythium in a number of vegetable crops, and Phytophthora in peas. Metalaxyl-M is the ISO common name [4] and Ridomil Gold is the trade name for the optically pure (-) / D / R active stereoisomer, which is also known as mefenoxam. [5]

Contents

It is the active ingredient in the seed treatment agent Apron XL LS. [6]

The fungicide has suffered severe resistance problems. The fungicide was marketed for use against Phytophthora infestans . However, in the summer of 1980, in the Republic of Ireland, the crop was devastated by a potato blight epidemic after a resistant race of the oomycete appeared. [7] Irish farmers later successfully sued the company for their losses.[ citation needed ] Maximum pesticide residue limits for the EU/UK are set at 0.5 mg/kg for oranges and 1.0 mg/kg for apples.[ citation needed ] As early as 1998 Pythium was known to be widely developing resistance to metalaxyl [8] which was the most effective control at the time. [8] Various Pythium populations have been known to have resistance to mefenoxam since the 1980s [9] and metalaxyl since 1984. [10] There is wide variability in resistance/sensitivity between Pythium species, with some populations showing complete ineffectiveness. [9]

Synthesis

The first synthesis of metalaxyl was disclosed in patents filed by Ciba Geigy. [11]

Metalaxyl synthesis V1.svg

2,6-Xylidine is alkylated with methyl 2-bromopropionate to give an alanine derivative. This is further reacted with the acid chloride of methoxyacetic acid to yield racemic metalaxyl. [11] [12] The homochiral, single-isomer version of the chemical, which retains all its fungicidal activity, has been manufactured. [13]

References

  1. ↑ O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. 13th Edition, Whitehouse Station, NJ: Merck and Co., Inc., 2001., p. 1058
  2. ↑ Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 134
  3. ↑ Sukul, P; Spiteller, M (2000). "Metalaxyl: persistence, degradation, metabolism, and analytical methods". Reviews of Environmental Contamination and Toxicology. 164: 1–26. PMID   12587832.
  4. ↑ "Compendium of Pesticide Common Names: metalaxyl". BCPC.
  5. ↑ Monkiedje, Adolphe; Spiteller, Michael (2002). "Effects of the phenylamide fungicides, mefenoxam and metalaxyl, on the microbiological properties of a sandy loam and a sandy clay soil". Biology and Fertility of Soils. 35 (6): 393–398. doi:10.1007/s00374-002-0485-1. S2CID   22642870.
  6. ↑ "bmz10s02.pdf" (PDF). Government of Manitoba. Archived from the original (PDF) on 2007-09-30.
  7. ↑ Working on potato blight in Northern Ireland
  8. 1 2 "Survey of Pythium Isolates for Resistance to Subdue (metalaxyl)" (PDF). UMass Amherst . Retrieved 2020-11-23.
  9. 1 2 Del Castillo Múnera, Johanna; Hausbeck, Mary K. (2016). "Characterization of Pythium Species Associated With Greenhouse Floriculture Crops in Michigan". Plant Disease . 100 (3). American Phytopathological Society: 569–576. doi: 10.1094/pdis-03-15-0296-re . ISSN   0191-2917. PMID   30688597.
  10. ↑ Sanders, P. L. (1984). "Failure of Metalaxyl to Control Pythium Blight on Turfgrass in Pennsylvania". Plant Disease . 68 (1). American Phytopathological Society: 776. doi:10.1094/pd-68-776. ISSN   0191-2917.
  11. 1 2 GBpatent 1500581,"Substituted amides and their use as fungicides",issued 1978-02-08, assigned to Ciba-Geigy AG
  12. ↑ Ishitani, Haruro; Yu, Zhibo; Ichitsuka, Tomohiro; Koumura, Nagatoshi; Onozawa, Shun-ya; Sato, Kazuhiko; Kobayashi, Shū (2022). "Two-Step Continuous-Flow Synthesis of Fungicide Metalaxyl through Catalytic C−N Bond-Formation Processes". Advanced Synthesis & Catalysis. 364: 18–23. doi:10.1002/adsc.202100898.
  13. ↑ Blaser, Hans-Ulrich; Spindler, Felix (1997). "Enantioselective catalysis for agrochemicals. The case histories of (S)–metolachlor, (R)–metalaxyl and clozylacon". Topics in Catalysis. 4 (3/4): 275–282. doi:10.1023/A:1019164928084.


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