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Photodegradation of the Isoxazolidine Fungicide SYP-Z048 in Aqueous Solution: Kinetics and Photoproducts

Liu, Pengfei, Xu, Yanjun, Li, Jianqiang, Liu, Junli, Cao, Yongsong, Liu, Xili
Journal of agricultural and food chemistry 2012 v.60 no.47 pp. 11657-11663
Ascomycota, Basidiomycota, Deuteromycotina, benzene, dechlorination, fruits, fungicides, high performance liquid chromatography, irradiation, mass spectrometry, mercury, nitrogen, nuclear magnetic resonance spectroscopy, photolysis, solid phase extraction, vegetables
Previous research has demonstrated that 3-[5-(4-chlorophenyl)-2,3-dimethyl-3-isoxazolidinyl]pyridine (SYP-Z048), a newly developed nitrogen heterocycle substituted isoxazolidine compound, has good protective and curative activities against a wide range of fungal diseases of fruits and vegetables caused by Ascomycetes, Basidiomycetes, and Deuteromycetes. In this study, the photochemical behavior of SYP-Z048 was investigated in aqueous solution and in response to solar and low-pressure mercury ultraviolet (UV) lamp irradiation. SYP-Z048 photolysis was pH- and temperature-dependent and was described by a first-order degradation reaction. A total of 11 photoproducts were separated by high-performance liquid chromatography (HPLC) and solid-phase extraction (SPE) and were identified on the basis of ¹H and ¹³C nuclear magnetic resonance (NMR) and high-performance liquid chromatography–mass spectrometry (HPLC–MS) spectra. The photoproduct structures and kinetics suggested that the phototransformation of SYP-Z048 occurred via multiple reaction pathways that included the cleavage of the N–O bond in the isoxazolidine ring and the dechlorination of the benzene ring.