Exploration of Some Heterocyclic Compounds Containing Trifluoromethylpyridine Scaffold as Insecticides Toward Aphis gossypii Insects

Five types of heterocyclic compounds containing trifloromethylpyridine scaffold namely; 3‐cyano‐2‐(N‐phenyl)carbamoylmethylthio‐6‐(thiophen‐2‐yl)‐4‐trifluoromethyl‐pyridine (6a), thieno[2,3‐b]pyridines 3‐5 and 7a‐c, pyrido[3',2':4,5]thieno[3,2‐d] pyrimidines 8‐13 and 15a‐c, pyrido[3',2':4,5]thieno[3,2‐d][1,2,3]triazines 16a,b, and 9‐(thiophen‐2‐yl)‐7‐(trifluoromethyl) pyrido [3',2':4,5]thieno[2,3‐e][1,2,4]triazolo[1,5‐c]pyrimidine (14) were synthesized in excellent yields and very pure state. The structures of these compounds were confirmed by elemental and spectral analyses. Most of the synthesized compounds were evaluated as insecticidal agents toward Aphis gossypii  insects and promising results obtained. Among all tested compounds, only 6, 7a, 7c and 15c being the most potent compounds against nymphs and adults of Aphis gossypii  and their activities are nearly to that of acetamiprid as a reference. The effect of 6a compounds 7a, 7c and 15c on the Aphis digestive system from histological point of view was also included.