The novel synthesis of a condensed triazine <i>via</i> the heterocyclization of an azo derivative and its characterization, radiolabeling and bio-evaluation

In heterocyclic chemistry, many studies have adopted the synthesis of novel benzotriazinone derivatives, as they have shown significant potential in biomedical research, particularly as enzyme inhibitors. This makes benzotriazinone a valuable scaffold for the development of new pharmaceuticals. Herein, a novel series of benzotriazinone derivatives was successfully synthesized, followed by docking studies. Ethyl 2-carboxyphenylazocyanoacetate was synthesized through the reaction of one mole of diazonium salt with a percentage of a mole of ethyl cyanoacetate in an alkaline medium. One of the derivatives, Triazine 12, exhibited promising <i>in silico</i> antitumor activity, according to molecular docking studies, which was then confirmed <i>in vitro</i> by determining its cytotoxicity against the human tumor cell lines HepG-2 and MCF-7, with IC₅₀ values of 78.53 ± 3.49 µg ml^-1 and 48.31 ± 2.37 µg ml^-1, respectively, in addition to low cytotoxicity against normal lung fibroblast cells (MRC-5), with a moderate antioxidant capacity shown in the DPPH radical scavenging assay. Furthermore, its suitability for radiolabeling as a tracer for <i>in vivo</i> studies was checked. Triazine 12 was directly radiolabeled with technetium-99m (^99mTc), yielding a radiochemical purity of 95.4% ± 0.46%. A biodistribution study in tumor-bearing mice of [^99mTc]-labeled Triazine 12 exhibited significant tumor targeting properties with positive T/NT ratios, reaching a peak of 4.65 (more than many tumoral radiopharmaceuticals) 1-hour post-injection, which highlights its potential as a novel radiotracer for tumor imaging.