Synthesis and Bioactivities of Novel Pyrazole Oxime Ester Derivatives Containing Pyridyl Moiety

Abstract

In order to explore novel pyrazole derivatives with good biological activities, a series of novel pyrazole oxime ester compounds containing pyridyl moiety were designed and synthesized according to the method of active substructure combination. The structures of the target compounds were determined by 1 H NMR, 13 C NMR and elemental analysis. Preliminary bioassay data indicated that some of the title compounds showed certain insecticidal activities. At a concentration of 500 μg/mL, seven compounds exhibited insecticidal activity against Oriental armyworm with 50%～90%, and six compounds exhibited insecticidal activity against Aphis medicaginis with 50%～90%. When the dosage was lowered to 100 μg/mL, 1,3-dimethyl-5-(4-chlorophenoxy)pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5f) and 1,3-dimethyl-5-(4-methylphenoxy)pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5j) were still active against Aphis medicaginis with inhibitory values of 50% and 50%, respectively. Insecticidal activities against Nilaparvata lugens of 1,3-dimethyl-5-(3-fluorophenoxy)pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5b) and 5f were both 100% at 500 μg/mL. Additionally, 1,3-dimethyl-5-(4fluorophenoxy)pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5c), 1,3-dimethyl-5-(3-chlorophenoxy)-pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5e), 1,3-dimethyl-5-(4-trifluoromethoxyphenoxy)pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5i) and 5j displayed good anti-tumor activity against HepG2 cells with IC 50 values of 2.6, 4.6, 1.8和 1.1 μmol/L, respectively.

Recent Research Progress in Oxime Insecticides and Perspectives for the Future

“…47 Shi further modified the pyrazole oxime ester derivatives by introducing pyridine rings in 2017. 48 Among them, compounds 48 and 49 (Figure 6L) demonstrated significant insecticidal activity against pests such as thrips, aphids, and brown planthoppers. These compounds also had substantial antitumor activity against human hepatocellular carcinoma (HepG2) cell strains, particularly compounds 48 and 49 with half maximal inhibitory concentration (IC 50 ) values of 1.8 and 1.1 μmol/L, respectively.…”

“…Shi obtained 5-substituted pyrazole compounds 46 and 47 with trifluoromethylbenzoyl oxime ester (Figure K), which exhibited moderate aphicidal activity at 500 μg/mL . Shi further modified the pyrazole oxime ester derivatives by introducing pyridine rings in 2017 . Among them, compounds 48 and 49 (Figure L) demonstrated significant insecticidal activity against pests such as thrips, aphids, and brown planthoppers.…”

Design, Synthesis, and Biological Activity Determination of Novel Phenylpyrazole Protoporphyrinogen Oxidase Inhibitor Herbicides Containing Five-Membered Heterocycles

“…This conclusion can also be verified based on the compounds previously synthesized by the research group. Therefore, the introduction of oxime ester bonds not only splices the two active structures together but also improves the shortcomings of current phenylpyrazole herbicide. − …”

Design, Synthesis, Crystal Structure, and Fungicidal Activity of L-Carvone Derivatives Containing an Oxime Ester Moiety

“…[14] Moreover, L-carvone was demonstrated to have fungicidal activities against fungi, such as Colletotrichum gloeosporioide, [15] Penicillium digitatum, [16] Alternaria citrii, [17] Botytts cinema, [18] and Colletotrichum gloeosporioides, [19] indicating that L-carvone can be used as a novel lead for the screening of fungicides. Oxime derivatives have a wide range of biological activities, including antitumor, [20] herbicidal, [21] insecticidal and acaricidal, [22][23] antiviral, [24] and antifungal activities. [19] Particularly, oxime derivatives such as trifloxystrobin and orysastrobin are used as commercial fungicides for controlling fungi such as Botrytis cinerea, and Phytophthora cryptogea (Figure 2).…”