title: Photodegradation of the isoxazolidine fungicide SYP-Z048 in aqueous solution: kinetics and photoproducts.
abstract: 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 (1)H and (13)C 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.
authors.affiliation: College of Agriculture and Biotechnology, China Agricultural University, Beijing 100193, People's Republic of China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Liu
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Xu
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Li
authors.forename: Junli
authors.initials: J
authors.lastname: Liu
authors.forename: Yongsong
authors.initials: Y
authors.lastname: Cao
authors.forename: Xili
authors.initials: X
authors.lastname: Liu
mesh_terms: D005659:Fungicides, Industrial / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007555:Isoxazoles / Q000737:chemistry*; D007700:Kinetics; D008027:Light; D010782:Photolysis; D011725:Pyridines / Q000737:chemistry*; D012996:Solutions; D013472:Sunlight; D013696:Temperature; D014466:Ultraviolet Rays; D014867:Water
chemical_list: D005659:Fungicides, Industrial; D007555:Isoxazoles; D011725:Pyridines; C578054:SYP-Z048; D012996:Solutions; D014867:Water