Zusammenfassung
Zur Voruntersuchung der Photostabilität des Fungicides Penconazol (1-(2,4-Dichlor-β-propylphenethyl)-1H-1, 2,4-triazol,1) wurden Modellexperimente in organischen Lösungsmitteln durchgeführt. Der Photoabbau (λ>280 nm) nimmt von Cyclohexen zu Cyclohexan und Isopropanol hin deutlich zu. Bei Bestrahlung in Isopropanol oder Cyclohexan entstehen als Hauptprodukte (1-(4-Chlor-β-propylphenethyl)-1H-1, 2,4-triazol (2) und 5H,6H-(1,2,4-Triazolo)-[5,1,-a]-9-chlor-6-propyl-isochinolin (3). Photodehalogenierung von 3 führt in geringem Umfang zu 5H,6H-(1,2,4-Triazo-lo)-[5, 1-a]-6-propyl-isochinolin(4) und in Gegenwart von Isopropanol zu 5H,6H-(1,2,4-Triazolo)-[5,1-a]-9-(2-hydroxy-2-methylethyl)-6-propyl-isochinolin (5) als Photoadditionsprodukt. Daneben entsteht in hohem Ausmaß eine komplexe Fraktion polarer Komponenten, die einer Einzelisolierung und -charakterisierung nicht mehr zugänglich waren. In Cyclohexen hingegen erfolgte neben Photodehalogenierung zu2 hauptsächlich Photolyse zu polaren Komponenten, während Photoprodukt3 nur in Spuren entstand.
Abstract
In order to examine the photostability of the fungicide penconazole (1-(2,4-dichloro-β-propylphenethyl)-1H-1,2,4-triazole,1) in the field, model experiments with organic solvents were performed. Photodegradation (λ>280 nm) of penconazole was found to be more efficient in isopropanol and cyclohexane solution than in the presence of cyclohexene. Photolysis in isopropanol and cyclohexane resulted in considerable formation of 1-(4-chloro-β-propylphenethyl)-1H-1,2,4-triazole (2) and 5H,6H-(1,2,4-triazolo)-[5,1-a]-9-chloro-6-propyl-isoquinoline (3). Furthermore, photodehalogenation of3 yielded traces of 5H,6H-(1,2,4-triazolo)-[5,1-a]-6-propyl-isoquinoline (4) and, in the presence of isopropanol 5H,6H-(1,2,4-triazolo)-[5,1-a]-9-(2-hydroxy-2-methylethyl)-6-propyl-isoquioline (5). Additionally, a lot of polar products were found in high yields which could not be isolated and characterized individually. In the presence of cyclohexene, on the other hand, photodecomposition and photodehalogenation to photoproduct2 were found to be the main degradation pathways and photoproduct3 was only detected as a trace component.
References
Walton TJ (1990) Methods Plant Biochem 4:105–158
Dureja P, Walia S, Mukerjee SK (1987) Toxicol Environ Chem 16:61–67
Clark T, Watkins DAM (1986) Chemosphere 15:765–770
Clark T et al. (1978) Pestic Sci 9:497–506
Clark T, James CS, Watkins DAM (1985) Chemosphere 14:1143–1150
Schwack W, Hartmann M (1992) Z Lebensm Unters Forsch 195:15–16
Hartmann M, Part of doctorate thesis, University of Karlsruhe (in preparation)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Schwack, W., Hartmann, M. Fungicides and photochemistry: Photodegradation of the azole fungicide penconazole. Z Lebensm Unters Forch 198, 11–14 (1994). https://doi.org/10.1007/BF01195274
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01195274