Li Z, Cong Y, Ma X, Wei Z, Cheng C, Shi F, Li S. Absolute configuration of four chiral isomers of pyrisoxazole and their bioactivity.
PEST MANAGEMENT SCIENCE 2020;
76:3780-3784. [PMID:
32452152 DOI:
10.1002/ps.5928]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 05/06/2020] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND
Pyrisoxazole is a fungicide that has two chiral carbon atoms and four isomers: (3S,5R)-, (3R,5S)-, (3S,5S)-, and (3R,5R)-pyrisoxazole.
RESULTS
Pure crystals of four pyrisoxazole isomers were prepared by chiral separation and single-crystal cultivation. Their absolute configurations were established by X-ray single crystal diffraction analysis. Bioassays indicated that compound (3S,5R)-pyrisoxazole showed excellent fungicidal activity with a median effective concentration (EC50 ) value of 0.14 μg mL-1 and protective activity with an EC50 value of 13.29 μg mL-1 . These values are superior to the commercial fungicides boscalid and racemic pyrisoxazole.
CONCLUSIONS
The biological activity of racemic pyrisoxazole is due almost exclusively to the isomer (3S,5R)-pyrisoxazole; the other three isomers had very low activity. © 2020 Society of Chemical Industry.
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