Synthesis of New Schiff Bases and Polycyclic Fused Thiopyranothiazoles Containing 4,6-Dichloro-1,3,5-Triazine Moiety

New aromatic aldimines, isatine substituted ketimines based on (4,6-dichloro-1,3,5-triazin-2-yl)-hydrazine scaffold and polycyclic fused thiopyranothiazoles formed using hetero-Diels-Alder reactions starting from 4-thioxo-2-thiazolidinones and 5-norbornene-2,3-dicarboxylic acid triazino-derivatives synthetic approach is described. The application of condensation and cyclocondensation reactions of N-nucleophiles and carbonyl agents for synthesis a number of biologically active triazine derivatives is reported. Screening of anticancer activity in vitro yielded the most active compounds 3a, 8b, and 8f for different cell lines.