Synthesis and insecticidal activities of novel pyrazole oxime ether derivatives with different substituted pyridyl rings

BACKGROUND Pyrazole oxime ether derivatives with different substituted pyridyl rings represent new types of compounds that possess good insecticidal and acarcidal activity against Aphis laburni Kaltenbach and Tetranychus cinnabarinus. RESULTS In total, 82 novel pyrazole oxime ether derivatives were synthesized and identified by 1H NMR, elemental analysis or high-resolution mass spectrometry, and their insecticidal and acarcidal activities were tested against A. laburni Kaltenbach and T. cinnabarinus. Bioassays showed that at a 200 mg L−1 dosage, one-third of the compounds displayed high insecticidal activity against A. laburni Kaltenbach (> 90%), whereas most of of the compound II series exhibited excellent acarcidal activity against T. cinnabarinus (> 92%). Most compound II series exhibited good activity in both insecticidal and acarcidal tests. In addition, at a low concentration of 10 mg L−1, the insecticidal activity of compounds IB9 and IE4 exceeded 90%, and the acarcidal activity of compounds IIB1 and IIB2 was ≥ 95%. CONCLUSION Structure–activity relationships were also examined. Results suggested that the tert-butoxycarbonyl group, as well as the position between tert-butoxycarbonyl and the atom N of the pyridyl ring, were essential to obtaining the acarcidal activity of the title compounds. © 2013 Society of Chemical Industry