As a result of some major problems that come from using
insecticides,
the use of safe alternatives to these pesticides has become very necessary.
Thus, a novel series of predicted toxicologically active urea, thiourea,
thiosemicarbazide, oxadiazole, pyrazole, and triazine derivatives
have been synthesized in a pure form to be lufenuron analogues as
insect growth regulators which were screened and examined against Spodoptera littoralis (Boisd). The structure of synthesized
compounds was established by means of spectroscopic and elemental
analyses. Compounds b5, b2, b3, and a4 showed high insecticidal toxicity, and their
LC50 values for the second larvae instar were found to
be 26.63, 46.35, and 60.84 ppm, respectively, whereas the LC50 value for lufenuron as a reference insecticide was 17.01 ppm.