The discovery of HNPC-A3066: a novel strobilurin acaricide.
BACKGROUND
Although more than ten strobilurin analogues have been commercialized since 1996 as fungicides, only one was available as an acaricide as of 2003. To search for novel strobilurin analogues with unique biological activities, a synthetic screening programme was carried out.


RESULTS
Syntheses of compounds analogous to the commercialized fungicide metominostrobin and the acaricide fluacrypyrim led to the discovery of a lead compound, (E)-2-[2-[[3,5-bis(trifluoromethyl)phenoxy]methyl]phenyl]-2-(methoxyimino)-N-methylacetamide (3b), that showed moderate acaricidal activity against Tetranychus urticae Koch. Compound 3b has a 3,5-(CF(3))(2)-phenoxymethyl group instead of the unsubstituted phenoxy substituent in metominostrobin. Optimization of compound 3b was achieved by introducing an oxime ether bridge along with an alkylthio(alkyl) branch in place of the oxymethylene chain between two aromatic moieties, as well as by replacing the methoxyiminoacetamide group with a methoxyacrylate structure, leading to (E)- methyl 2-[2-[[[(Z)[1-(3,5-bis(trifluoromethyl)phenyl)-2-methylthioethylidene]amino]oxy] methyl]phenyl]-3-methoxyacrylate (6c) and (E)- methyl 2-[2-[[[(Z)[1-(3,5-bis(trifluoromethyl)phenyl)-1-methylthiomethylidene]amino]oxy]methyl]phenyl]-3-methoxyacrylate (9a, HNPC-A3066).


CONCLUSIONS
The above two compounds (6c, 9a) were shown to exhibit potent acaricidal and fungicidal activity. Compound 9a (HNPC-A3066) also exhibits larvicidal and ovicidal activities against various acarids. The acaricidal potency is comparable with those of commercial acaricides such as fluacrypyrim, tebufenpyrad and chlorfenapyr.
Liu
Aiping
A
National Engineering Research Centre for Agrochemicals, Hunan Research Institute of Chemical Industry, Changsha 410007, China. lapliu@yahoo.com
Wang
Xiaoguang
X
Chen
Can
C
Pei
Hui
H
Mao
Chunhui
C
Wang
Yongjiang
Y
He
Haijun
H
Huang
Lu
L
Liu
Xinping
X
Hu
Zhibin
Z
Ou
Xiaoming
X
Huang
Mingzhi
M
Yao
Jianren
J
D000053:Acari / Q000187:drug effects*; D000818:Animals; D055808:Drug Discovery; D005659:Fungicides, Industrial / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D007306:Insecticides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D008689:Methacrylates / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship
D005659:Fungicides, Industrial; D007306:Insecticides; D008689:Methacrylates