Difenoconazole

Difenoconazole
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.106.375 Edit this at Wikidata
EC Number
  • 601-613-1
KEGG
  • InChI=1S/C19H17Cl2N3O3/c1-13-9-25-19(27-13,10-24-12-22-11-23-24)17-7-6-16(8-18(17)21)26-15-4-2-14(20)3-5-15/h2-8,11-13H,9-10H2,1H3
    Key: BQYJATMQXGBDHF-UHFFFAOYSA-N
  • CC1COC(O1)(CN2C=NC=N2)C3=C(C=C(C=C3)OC4=CC=C(C=C4)Cl)Cl
Properties
C19H17Cl2N3O3
Molar mass 406.26 g·mol−1
Density 1.39 g·cm−3
Hazards
GHS labelling:
GHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
Warning
H302, H319, H351, H410
P203, P264, P264+P265, P270, P273, P280, P301+P317, P305+P351+P338, P318, P330, P337+P317, P391, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).


Difenoconazole is a mixture of several isomers of a chemical compound belonging to the group of triazoles and conazoles. It is used as a fungicide.

Properties

Difenoconazole is a white, odorless solid that is practically insoluble in water. The technical-grade product is yellowish and has a faintly sweet odor. The compound is stable against photolysis and hydrolysis at pH values of 5, 7, and 9.

Stereoisomers

Due to the two stereocenters in the five-membered acetal ring, difenoconazole forms a cis-trans pair of racemic diastereomers. The mixture therefore consists of four stereoisomers: the (R,R)-, (S,S)-, (R,S)-, and (S,R)-forms. The ratio of diastereomers after synthesis is approximately 60% cis isomers [(R,S)- and (S,R)-forms] and 40% trans isomers [(R,R)- and (S,S)-forms].

Difenoconazole
(4 stereoisomers)
(R,R)-difenoconazole
(R,R) configuration		 (S,S)-difenoconazole
(S,S) configuration
(S,R)-difenoconazole
(S,R) configuration		 (R,S)-difenoconazole
(R,S) configuration

Synthesis and Preparation

Difenoconazole can be obtained by ether reaction of 2,4-dichloroacetophenone with 4-chlorophenol, followed by bromination of the intermediate with elemental bromine, followed by the formation of an acetal with 1,2-propanediol and nucleophilic substitution with 1,2,4-triazole.

Synthesis of difenoconazole
Synthesis of difenoconazole

Uses

Difenoconazole is a systemic triazole fungicide used to control a range of plant diseases affecting fruits, vegetables, and ornamental plants, including those caused by Ascomycetes, Basidiomycetes, and Deuteromycetes. It inhibits fungal ergosterol biosynthesis by blocking the C-14demethylation of steroids, resulting in morphological and functional changes in the fungal cell membrane. The compound was introduced to the market in 1989. Its use in strawberry cultivation can reduce the aroma and flavor of the fruit.

In the European Union, the substance was included in Annex I of Directive 91/414/EEC concerning the placing of plant protection products on the market, pursuant to Directive 2008/69/EC.

In Germany, Austria, and Switzerland, plant protection products containing this active ingredient are approved.

In Switzerland, a relatively high residue limit in food of 10 milligrams of difenoconazole per kilogram applies, among other products, to basil and parsley.

References

  1. 1 2 FAO: Difenoconazole (PDF; 1,0 MB).
  2. ↑ US 9462807, J. R. Godwin, A. M. Heming, C. Lothschuetz, P. Schneiter, W. Stutz, "Difenoconazole sterepospmeric composition with reduced phytotoxicity", published 2014-01-27
  3. ↑ Thomas A. Unger (1996), Pesticide synthesis handbook, Elsevier Science, p. 691, ISBN 978-0815514015
  4. ↑ Europäische Behörde für Lebensmittelsicherheit (EFSA): Reasoned opinion on the modification of the existing MRLs for difenoconazole in various crops. In: EFSA Journal. 11, 2013, S. 3149, doi:10.2903/j.efsa.2013.3149.
  5. ↑ Horst Börner, Klaus Schlüter (2009), Pflanzenkrankheiten und Pflanzenschutz, Springer, p. 496, ISBN 978-354049068-5
  6. ↑ Yuping Liu, Rui Liu, Yue Deng, Meiling Zheng, Simin Yu, Yufan Nie, Jia-Qi Li, Canping Pan, Zhiqiang Zhou, Jinling Diao: Insights into the Mechanism of Flavor Loss in Strawberries Induced by Two Fungicides Integrating Transcriptome and Metabolome Analysis in J. Agric. Food Chem. 71 (2023) 3906–3919, doi:10.1021/acs.jafc.2c08157.
  7. ↑ http://data.europa.eu/eli/dir/1991/414 {{citation}}: Missing or empty |title= (help) des Rates vom 15. Juli 1991 über das Inverkehrbringen von Pflanzenschutzmitteln.
  8. ↑ "Richtlinie 2008/69/EG der Kommission vom 1. Juli 2008". 2008. zur Änderung der Richtlinie 91/414/EWG des Rates zwecks Aufnahme der Wirkstoffe Clofentezin, Dicamba, Difenoconazol, Diflubenzuron, Imazaquin, Lenacil, Oxadiazon, Picloram und Pyriproxyfen.
  9. ↑ "EU Pesticides Database". ec.europa.eu. Retrieved 2026-10-25.
  10. ↑ "Verordnung des EDI über die Höchstgehalte für Pestizidrückstände in oder auf Erzeugnissen pflanzlicher und tierischer Herkunft". admin.ch. Retrieved 2020-02-06.