Potential drugs within a series of 3-phenylethyl-8-(R-phenyl)-7,8-dihydroimidazo[2,1-c][1,2,4]triazin-4(6H)-ones exhibit favourable toxicity profiles and thermal behaviours

The article presents the toxicity profile and detailed thermal behaviour of potential anticancer drugs ( 1–5 ). Considering mortality, hatchability, heartbeat, and developmental abnormalities, the tested dihydroimidazotriazinones revealed lower toxicity to zebrafish embryos/larvae than pemetrexed. They did not show any haemolytic effects, indicating good haemocompatibility. Molecules 3 and 4 protected oxidatively-stressed erythrocytes more effectively than antioxidant standards. In silico prediction confirmed the acceptable safety profile and pharmacokinetic properties of compounds, indicating their suitability as drug candidates. Thermal studies were performed using DSC, TG/DTG and simultaneous TG/FTIR/QMS techniques. All compounds exhibited sharp melting points and high thermal stability. Both pyrolysis and oxidative decomposition led to the emission of NH 3 , CH 3 CN, HCN, HNCO, aromatics, alkenes, and small amounts of CO 2 and H 2 O during the first decomposition stage, indicating simultaneous cleavage of N–N, C–N, and C–C bonds. The second stage was mainly associated with the formation of CO 2 and CO, along with low HCN emissions (in helium), and CO 2 , CO, H 2 O, HNCO, NO/NO 2 , and low emissions of HCN (in synthetic air). This suggests the occurrence of secondary pyrolysis processes of the formed residues under inert conditions, and the oxidation and combustion of nitrogen- and oxygen-rich intermediates and residues under oxidative conditions.