Synthesis of Benzoxazole Associated Benzothiazine-4-ones and their in vitro and in silico Antimicrobial, Antioxidant Activities

Abstract

In present study, a series of 3-[(5-methyl-1,3-benzoxazol-2-yl)amino]-2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones (6a-n) were synthesized and elucidated by elemental, FT-IR, ¹H & ¹³C NMR and LC-MS studies. The in vitro antibacterial screening against Gram-positive bacterial strains such as B. subtilis, S. aureus, S. epidermidis and Gram-negative bacteria such as E. coli, P. aeruginosa was carried in comparison with tetracycline as reference standard. Antifungal activities against different fungal strains namely R. oryzae, A. niger, A. favus, C. albicans and S. cerevisiae have been evaluated by comparing with fluconazole as reference standard. Compounds 6b, 6c, 6e, 6j, 6m and 6n emerged as highly potent antimicrobial agents. The DPPH radical scavenging assay of the synthesized moieties showed good antioxidant potency comparable to standard ascorbic acid. The molecular docking simulation studies of all the title compounds in their active conformation analogues with target proteins (PDB ID 2XCT-antibacterial, PDB ID 1IYL-antifungal, PDB ID 2HCK- antioxidant) exhibited good binding interactions in top scoring poses. The pharmacokinetic properties prediction by ADMET descriptors and Lipinski′s rule of five endorse the properties of newly synthesized compounds to a drug molecule. The results of the docking protocols were compatible with the in vitro studies which validates the potency of the molecules.