Novel Approach in the Synthesis of Some Pyrimidines with Eminent Toxicological Effects towards <i>Aphis gossypii</i> ( <i>Glover</i> , 1887) and Outstanding Safety against Earthworms ( <i>Aporrectodea caliginosa</i> )

This study reports the synthesis and bioevaluation of ten novel pyranothiazolopyrimidine derivatives. Their insecticidal efficacy against Aphis gossypii ( Glover, 1887) revealed compounds 3 and 10 as lead candidates, exhibiting toxicity comparable to the commercial standard acetamiprid insecticide. Notably, these compounds demonstrated a markedly safer ecotoxicological profile toward the earthworms ( Aporrectodea caliginosa ), with LC 50 values orders of magnitude higher than acetamiprid over 5- and 10-day exposures. Application also induced measurable changes in soil chemistry. These findings identify compounds 3 and 10 as promising insecticidal agents that combine potent aphid toxicity with significantly reduced nontarget risk, highlighting their potential for further development.