Recyclable CaSiO ₃ ‐Catalyzed Synthesis and Characterization of Indeno[1, 2‐d] Pyrimidine Derivatives: In Silico and Preliminary Biological Screening

An efficient synthetic route was developed for indeno[1,2-d]pyrimidinone and indeno[1,2-d]pyrimidinethione derivatives via a modified Biginelli condensation of aryl aldehydes, 5-chloroindanone, and urea/thiourea. The reaction, catalyzed by recyclable calcium silicate, proceeded under mild conditions to afford the target compounds in good to high yields, with the catalyst maintaining activity over multiple cycles. The catalyst was characterized using powder x-ray diffraction, scanning electron microscopy, and transmission electron microscopy to confirm its structural integrity. The molecular structures of the synthesized derivatives were supported by proton nuclear magnetic resonance, infrared spectroscopy, and mass spectrometry. Green chemistry metrics, including atom economy, reaction mass efficiency, and E-factor, were used to evaluate the sustainability of the developed synthetic protocol. Density functional theory calculations provided insights into the electronic properties of the compounds. Preliminary and complementary biological studies, including cytotoxicity screening, DNA binding, and cleavage, were carried out to explore potential biological behavior. Preliminary molecular docking with A/B -DNA was also performed to provide a tentative understanding of possible interactions. A predictive structure-activity trend analysis was carried out to correlate structural features with observed trends in cytotoxicity. These biological evaluations are exploratory in nature, intended for the identification of promising leads for further study.