Design, synthesis, <i>in vitro</i> cytotoxic activity, and <i>in silico</i> studies of symmetrical chlorophenylamino- <i>s</i> -triazine derivatives

Twenty symmetrical chlorophenylamino-<i>s</i>-triazine derivatives were designed and synthesized by reflux (RF) and microwave-assisted (MW) methods. The MW method achieved superior yields (88-95%) in less time (15-30 min) compared to RF (78-86%, 12-24 h), particularly for 3-Cl and 3,4-diCl derivatives with piperidine or diethylamine, due to rapid, uniform heating, enhancing nucleophilic substitution and minimizing side reactions. In particular, compounds 2c (IC₅₀ = 4.14 μM for MCF7, 7.87 μM for C26), 3c (IC₅₀ = 4.98 μM for MCF7, 3.05 μM for C26), and 4c (IC₅₀ = 6.85 μM for MCF7, 1.71 μM for C26) exhibited potent cytotoxic activity with 4c (2,4-diCl, pyrrolidine) surpassing paclitaxel (IC₅₀ = 2.30 μM for C26), and 3c (3,4-diCl, pyrrolidine) rivaling global analogs. Compounds 2f (IC₅₀ = 11.02 μM for MCF7, 4.62 μM for C26) and 3f (IC₅₀ = 5.11 μM for MCF7, 7.10 μM for C26) also showed strong cytotoxicity. QSAR analysis revealed that electron-withdrawing groups (chloro, dichloro) and pyrrolidine enhance C26 potency <i>via</i> improved lipophilicity and π-π stacking, outperforming piperazine and morpholine. Pharmacokinetically, 2c, 3c, and 4c matched Bimiralisib's absorption profiles, surpassing Gefitinib, with 4c showing superior metabolic stability. Compounds 2f and 3c emerged as promising multi-targeted kinase inhibitors, with binding affinities (-7.8 to -9.1 kcal mol^-1) closely rivaling Gefitinib, Pazopanib, and Bimiralisib for EGFR, VEGFR2, and PI3K, driven by balanced polar and hydrophobic interactions. Therefore, these findings underscore the potential of 2f and 3c as multi-targeted kinase inhibitors, warranting further mechanistic studies and structural optimization to enhance MCF7 efficacy and reduce toxicity for clinical advancement.