Synthesis, Photophysical Properties, and Biological Evaluation of New Thiazolo[3,2- <i>a</i> ]pyrimidine Derivatives as Promising Insecticidal and Anti-inflammatory Agents

The increasing resistance of insects to conventional pesticides drives the search for new bioactive heterocycles with novel modes of action. An efficient one-pot protocol was developed for the synthesis of new aminothiazolo[3,2-<i>a</i>]pyrimidine-2-carboxamides as key precursors to pyrimido[4',5':4,5]thiazolo[3,2-<i>a</i>]pyrimidines, offering high yields, short reaction times, and operational simplicity. Density functional theory calculations confirm preferential formation of the thermodynamically stable isomers. Assignment of the chemical structures for the newly synthesized heterocycles was confirmed utilizing elemental and spectral techniques. Furthermore, photoluminescence studies revealed aggregation-induced emission behavior for selected derivatives (<b>2b</b> and <b>6</b>). Biological evaluation demonstrated notable anti-inflammatory activity, with morpholine-substituted compound <b>5c</b> showing enhanced efficacy. Insecticidal screening against Aphis gossypii identified compound <b>5a</b> as the most active candidate, supported by molecular docking indicating strong interaction with the nAChR target. These results highlight compound <b>5a</b> as a promising lead for insecticidal development. The previous findings were supported by molecular docking studies.