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Design, synthesis and fungicidal activity of 11‐alkoxyimino‐5,6‐dihydro‐dibenzo[ b , e ] azepine‐6‐one derivatives
Author(s) -
Xiao Yanshuang,
Yan Xiaojing,
Xu Yanjun,
Huang Jiaxing,
Yuan Huizhu,
Liang Xiaomei,
Zhang Jianjun,
Wang Daoquan
Publication year - 2013
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.3440
Subject(s) - azepine , botrytis cinerea , chlorothalonil , fungicide , sclerotinia sclerotiorum , stereochemistry , piperidine , chemistry , biology , botany
Background Macrocyclic compounds with an oxime ether side chain, discovered in Wang's group, showed good fungicidal activity. However, the long synthetic route makes the cost too high for them to be developed further as practical fungicides. Alternative compounds with good fungicidal activity and an easier synthesis than the above‐mentioned macrolactams were sought, and a series of 11‐alkoxyimino‐5,6‐dihydro‐dibenzo[ b,e ]azepine‐6‐one derivatives (4) were designed and bioassayed . Results The structures were confirmed by 1 H NMR , 13 C NMR and LC‐MS . The bioassay showed that about half of the 11‐alkoxyimino‐5,6‐dihydro‐dibenzo[ b , e ]azepine‐6‐one derivatives (4) displayed good fungicidal activity against Sclerotinia sclerotiorum (Lib.) de Bary, with EC 50 values <15 µg mL −1 . 11‐( n ‐Butyloxyimino)‐5,6‐dihydro‐dibenzo[ b , e ]azepine‐6‐one ( 4A ‐05), 11‐(4‐nitrobenzyloxyimino)‐5,6‐dihydro‐dibenzo[ b , e ]azepine‐6‐one ( 4A ‐12) and 11‐(2‐chloro‐6‐fluorobenzyloxyimino)‐5,6‐dihydro‐dibenzo[ b , e ]azepine‐6‐one ( 4A ‐21) displayed excellent fungicidal activity, with EC 50 values of <2.5 µg mL −1 , much better than the commercial fungicide chlorothalonil with an EC 50 value of 7.16 µg mL −1 . In addition, about half of the 11‐alkoxyimino‐5,6‐dihydro‐dibenzo[ b , e ]azepine‐6‐one derivatives (4) had good fungicidal activity against Botrytis cinerea (De Bary) Whetzel, with EC 50 values of <10 µg mL −1 . 11‐(2‐Fluorobenzyloxyimino)‐5,6‐dihydro‐dibenzo[ b , e ]azepine‐6‐one ( 4A ‐16), 11‐(3‐fluorobenzyloxyimino)‐5,6‐dihydro‐dibenzo[ b , e ]azepine‐6‐one ( 4A ‐17) and 11‐(2‐chloro‐6‐fluorobenzyloxyimino)‐5,6‐dihydro‐dibenzo[ b , e ]azepine‐6‐one ( 4A ‐21) displayed excellent fungicidal activity, with EC 50 values of 3.73, 2.54 and 3.20 µg mL −1 respectively, comparable with the commercial fungicide procymidon with an EC 50 value of 2.45 µg mL −1 . Their structure–activity relationship is discussed . Conclusions The present work demonstrates that the title compounds show promise as fungicides. © 2013 Society of Chemical Industry