Fluazinam is a broad-spectrum fungicide used in agriculture. It is classed as a diarylamine and more specifically an arylaminopyridine. Its chemical name is 3-chloro-N-(3-chloro-2,6-dinitro-4-trifluoromethylphenyl)-5-trifluoromethyl-2-pyridinamine.[1] The mode of action involves the compound being an extremely potent uncoupler of oxidative phosphorylation in mitochondria[2] and also having high reactivity with thiols.[1] It is unique amongst uncouplers in displaying broad-spectrum activity against fungi and also very low toxicity to mammals due to it being rapidly metabolised to a compound without uncoupling activity.[1][3] It was first described in 1992 and was developed by researchers at the Japanese company Ishihara Sangyo Kaisha.[4]

Fluazinam
Names
Preferred IUPAC name
3-Chloro-N-[3-chloro-2,6-dinitro-4-(trifluoromethyl)phenyl]-5-(trifluoromethyl)pyridin-2-amine
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.114.073 Edit this at Wikidata
UNII
  • InChI=1S/C13H4Cl2F6N4O4/c14-6-1-4(12(16,17)18)3-22-11(6)23-9-7(24(26)27)2-5(13(19,20)21)8(15)10(9)25(28)29/h1-3H,(H,22,23)
    Key: UZCGKGPEKUCDTF-UHFFFAOYSA-N
  • InChI=1/C13H4Cl2F6N4O4/c14-6-1-4(12(16,17)18)3-22-11(6)23-9-7(24(26)27)2-5(13(19,20)21)8(15)10(9)25(28)29/h1-3H,(H,22,23)
    Key: UZCGKGPEKUCDTF-UHFFFAOYAY
  • C1=C(C=NC(=C1Cl)NC2=C(C=C(C(=C2[N+](=O)[O-])Cl)C(F)(F)F)[N+](=O)[O-])C(F)(F)F
Properties
C13H4Cl2F6N4O4
Molar mass 465.09 g·mol−1
Density 1.8±0.1 g/cm3
Melting point 116 °C (241 °F; 389 K)
Boiling point 376.1±42.0°C (Predicted)
1.76 mg/L
Vapor pressure 5.51×10−8 mmHg (Predicted)
Hazards
Lethal dose or concentration (LD, LC):
5000mg/kg (rat, oral)
4190mg/kg (mallard, oral)
≥200μg (bee, contact)
≥1000mg/kg (worm, 28 day)
61ppb (rainbow trout, 96h)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Uses

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Fluazinam is a protectant fungicide, but is neither systemic or curative. It acts by inhibiting the germination of spores and the development of infection structures. Although it has activity against many fungi, it is less potent against rusts and powdery mildew and as such has not been commercialised for use in cereal crops. It is widely used to control late blight (P. infestans) in potato due to its activity against the zoospores of the pathogen which makes it particularly effective at controlling infection of the potato tubers. Because of its extensive usage to control late blight in Europe, there are confirmed reports of resistance to fluazinam appearing in P. infestans in genotypes EU_33_A2 and EU_37_A2.[5] Fluazinam is also used to control Sclerotinia on peanuts and turf, Botrytis on grapes and beans and clubroot in brassicas.[1]

Toxicity

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The acute oral median lethal dose in rats is very low at over 5000 mg/kg due to the compound's reactivity with thiols. This reactivity can have negative consequences since repeated exposure can cause skin sensitization and dermatitis to develop in some individuals. Fluazinam also displays low toxicity to birds, bees and worms, but has a high toxicity to fish. The toxicity towards fish is considered to be relatively unimportant, since the compound has a very short half-life (around 1 day) in aquatic systems.[1]

References

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  1. ^ a b c d e Ulrich Schirmer; Peter Jeschke; Matthias Witschel (2012). Modern Crop Protection Compounds: Herbicides. John Wiley & Sons. pp. 662–663. ISBN 978-3-527-32965-6.
  2. ^ Ze-jian Guo; Hideto Miyoshi; Terumasa Komyoji; Takahiro Haga; Toshio Fujita (1991). "Uncoupling activity of a newly developed fungicide, fluazinam [3-chloro-N-(3-chloro-2,6-dinitro-4-trifluoromethylphenyl)-5-trifluoromethyl-2-pyridinamine]". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1056 (1): 89–92. doi:10.1016/S0005-2728(05)80077-5.
  3. ^ Society for General Microbiology. Symposium (4 May 1995). Fifty Years of Antimicrobials: Past Perspectives and Future Trends. Cambridge University Press. pp. 104–105. ISBN 978-0-521-48108-3.
  4. ^ Robert Krieger (17 October 2001). Handbook of Pesticide Toxicology, Two-Volume Set: Principles and Agents. Academic Press. p. 1243. ISBN 978-0-08-053379-7.
  5. ^ Schepers, Huub; Kessel, Geert; Lucca, F; Forch, M; van den Bosch, G; Topper, C; Evenhuis, A (2018). "Reduced efficacy of fluazinam against Phytophthora infestans in the Netherlands". European Journal of Plant Pathology. 151 (4): 947. doi:10.1007/s10658-018-1430-y. PMC 6435203.