This manuscript reports the preparation and toxicological efficacy testing of nine oxoimidazolidine and cyanoguanidine compounds (3a, 3b, 3c, 3d, 3e, 3f, 3g 4a, and 4b) against cowpea aphid, Aphis craccivora Koch. Bioefficacy data revealed that the tested compounds exhibited a range of toxicological activities against these insects, with compound 3b being the most toxic and compound 4a being the least effective. The LC50 value of compound 3b was 1.72 ppm for adults and 0.02 ppm against nymphs of the cowpea aphid, while the LC₅₀ value of compound 4a was 72.51 ppm for adults and 18.02 ppm against nymphs. The manuscript also presents the structure-activity relationships of these compounds. These results provide valuable insights into the development of effective pest control agents for the management of such insects.

This work includes the synthesis of ten heterocyclic compounds (3a-i and 4) containing pyrimidine moiety incorporated in their structures. Structure characterizations of these compounds were performed by using elemental and spectroscopic analyses. Their toxicity as potential insecticidal agents against the adults and nymphs of cowpea Aphid, Aphis craccivora Koch was evaluated. The results of this toxicological activity test revealed that a reasonable number of these compounds possess excellent toxicological activity against cowpea aphids such as compounds (3d), (3c), and (3b) with LC50 values 0.0125, 0.0134, and 0.0383 ppm, respectively. The toxicological activities of the rest of the tested compounds ranged from good to moderate against the same insects.

In this study, seven cyano-benzylidene and bisbenzylidene derivatives were designed and synthesized. All synthesized compounds were evaluated to determine their insecticidal activities as potential insecticides against nymphs and adults of Aphis nerii. These efforts led to the discovery of compounds 3a-d, 5, 7 and 10 with potent insecticidal activity (LC50 range from 0.0141 to 3.4351ppm). Compound 5 exhibited the highest insecticidal potency with 0.0141ppm. In addition, it indicated that compound 3b is less toxic than benzylidene and other precursors. Therefore, our results suggest that compound 5 has strong potential as a candidate component for developing a novel eco-friendly insecticide for control Aphids.

In our work we study the toxic effects of the prepared pyridine and pyradazine derivatives. Five compounds have been synthesized in pure state as reported procedures, and their toxicity as potential insecticidal agents against adult and nymphs of Aphis nerii were screened. The toxicity data in adults, exhibited that compound 6a is more toxic than other synthesized compounds, which LC50 was1.04 ppm while, in nymph compound 4a is more toxic than other synthesized compounds, which LC₅₀ was 0.02 ppm. The other screened compounds showed weak to strong toxicological activity. The structure-activity relationships (SAR) for these compounds were also discussed.

Spodopetra Frugiperda is a highly polyphagous migratory lepidopteran pest species. It causes infestation in crops leading to severe crop losses. Being a new invasive parasite, its susceptibility to insecticides needs to be explored and therefore, there is an urgent need to develop the potent insecticides for the effective control of this insect pest. This is the first report on toxic effects produced by the prepared chalcone and hydrazone analogs, followed by structure relationships. Five compounds of chalcone and hydrazone derivatives have been synthesized in pure state as reported procedures, and their toxicity as potential insecticidal agent against Spodopetra Frugiperda was screened. Their characterizations by using spectroscopic analyses were performed. The toxicity data exhibited that compound 5 is more toxic about 2-fold than other synthesized compounds, the other screened compounds showed weak to strong toxicological activity against Spodopetra Frugiperda (lepidoptera: Noctuidae).

A series of furan derivatives tebufenozide analogues comprising five compounds (2, 3, 4, 5, and 6) have been designed and synthesized via reaction of N'-phenylfuran-2-carbohydrazide (1) with different acid chlorides. The structures of the synthesized compounds were identified by elemental analyses and spectroscopic data. The analogues compounds have the active center of tebufenozide (mimic) with change of tertiary butylhydrazine by phenylhydrazine. Studying the effect of this change on the toxicological activity against Spodoptera littoralis larvae was performed for three compounds of the synthesized ones. Toxicological activity data showed that compound (3) is more active than compounds (2) and (5)

Many of mimic analogues synthesized before depending on the change in the structure of aromatic rings. In this work, the carbonyl group in the structure of compounds 1-4 converted to thiocarbonyl group, and then studying the toxicological activity due to chemical change in the active center of mimic analogues was performed for compounds N-tert-butyl-2,4-dichloro-N'-(2,4-dichlorobenzoyl)benzohydrazide (2) and N-tert-butyl-2,4-dichloro-N'-[(2,4-dichlorophenyl)carbonothioyl]benzenecarbothiohydrazide (6). The toxicological study was done by using 2nd and 4th instar larvae of the cotton leaf worm, Spodoptera littoralis (Boisd.). Five concentration levels (600, 300, 150, 75 and 37.5 ppm) of compounds (2) and (6) were applied on the fresh plant food to the newly grown (2^nd and 4^th) instar larvae.

Reaction of N-cyanoguanidine with acid chlorides and aroylisothiocyanates gave the respective; N-(N-cyanocarbamimidoyl)aryl-2-carboxamides 1-5 and N-[(N-cyanocarbamimidoyl)carbamothioyl]benzamides 6-10, which have a Neonictinoid insecticide’s active group moiety (=N–CN). They have more toxicological activity against wheat Aphid (Schizaphis graminum) than Spodoptera littoralis.