Synthesis, characterization and molecular docking studies of novel 6-Imino-2-Methyl-4-substituted- 6H -1,3-Thiazine-5-Carbonitrile derivatives as potential antibacterial agents

Novel 6-imino-2-methyl-4-substituted-6H-1,3-thiazine-5-carbonitrile derivatives were synthesized via cyclocondensation of thioacetamide and bis(methylthio)methylene malononitrile in DMF using K 2 CO₃. The key 4-methylthio intermediate underwent nucleophilic substitution with various anilines, phenols, heterocyclic amines, and active methylene compounds to produce a diverse library. All structures were confirmed using IR, 1H NMR, 13C NMR and mass spectrometry. The antibacterial potential of twelve selected derivatives was evaluated through molecular docking against the DNA Gyrase B ATP-binding pocket (PDB: 1KZN). Utilizing CB-Dock2, AutoDock Vina, and PLIP analysis, the study predicted binding affinities and interaction profiles. Favourable binding energies and significant intermolecular interactions highlight these thiazine derivatives as promising leads for further antibacterial development.