Design, synthesis, and insecticidal activities of phthalamides containing a hydrazone substructure.
Fluobendiamide is the first commercialized artificial synthetic insecticide acting on the ryanodine receptor. This new molecule possesses a combination of excellent insecticidal activity and eco-friendly characteristics with a skeleton structure of phthalamide. In this study, we incorporated hydrazone, present in many pesticidal compounds reported during the last two decades, into phthalamide derivatives via Schiff-base condensation and aminolysis to obtain 21 new compounds; these compounds were characterized by proton nuclear magnetic resonance ((1)H NMR), infrared spectroscopy (IR), and high-resolution mass spectrometry (HRMS) or elemental analysis. A preliminary bioassay against peach aphids ( Myzus persicae ) revealed that the title compounds exhibited good stomach toxicity at 600 mg/L. Twelve new compounds were found to display higher activity than postive control flubendiamide (LC(50) = 184.099 mg/L), however, LC(50) was less than 100 mg/L only for compounds 4e, 4o, 4s, 4t (59-77 mg/L). That is, combinations of a p-fluorophenyl or (methyl)thienyl group at the Ar position with an isopropyl or cyclohexyl group at the R position might improve the lethality of the designed phthalamide derivative. Preliminary results of a bioassay at 600 mg/L against diamondback moth ( Plutella xylostella , Linnaeus) showed that only the title compound 4e possessed good larvicidal activity. On comparison of the bioassay results of stomach toxicity and larvicidal activity, it is noteworthy that the compound incorporating phenylpyrazolyl exhibited good larvicidal activity and poor stomach activity.
Liu
Ming
M
Key Laboratory of Pesticide Chemistry and Application, Ministry of Agriculture, Department of Applied Chemistry, China Agricultural University, Beijing 100193, People's Republic of China.
Wang
Yi
Y
Wangyang
Wei-zi
WZ
Liu
Feng
F
Cui
Yong-liang
YL
Duan
You-sheng
YS
Wang
Min
M
Liu
Shang-zhong
SZ
Rui
Chang-hui
CH
D000818:Animals; D001042:Aphids / Q000187:drug effects; D015195:Drug Design; D006835:Hydrazones / Q000737:chemistry*; D007306:Insecticides / Q000138:chemical synthesis* / Q000737:chemistry / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D015394:Molecular Structure; D009036:Moths / Q000187:drug effects / Q000254:growth & development; D010795:Phthalic Acids / Q000138:chemical synthesis* / Q000737:chemistry / Q000633:toxicity*; D013329:Structure-Activity Relationship
D006835:Hydrazones; D007306:Insecticides; D010795:Phthalic Acids