Pyridine derivatives as insecticides. Part 2: Synthesis of some piperidinium and morpholinium cyanopyridinethiolates and their insecticidal activity

The work included in this paper involves the synthesis of thirteen heterocyclic compounds, piperidinium and morpholinium 3-cyanopyridinethiolates 5-14, 17, 20 and 21 in our Lab. and their characterization using elemental and spectroscopic analyses. The insecticidal activities of these compounds against cowpea aphid, Aphis craccivora using acetamiprid insecticide as a reference were studied. The bioassay results showed that: (i) the insecticidal activities of compounds 13, 14 and 20 against nymphs or adults of cowpea aphid are about 1.5-fold higher than that of acetamiprid after 48 h of treatment, (ii) the rest of the tested compounds (ten compounds) exhibit weak to strong toxicity against cowpea aphid and (iii) there is a remarkable relationship between the structure and activity of the tested compounds.