A green and expedient synthesis of [1, 3] oxazine derivatives and their biological evaluation as a potent anti-tubercular and anti-microbial agent.

An efficient and green protocol for the multicomponent one-pot synthesis of [1, 3] oxazine derivatives has been achieved by encapsulating a biomolecule on a solid magnetic support. This methodology encompasses mild reaction conditions, ease of catalyst separation, and catalyst reusability. Further, the use of ultrasonic energy in the reaction not only led to improved yield but also to a shorter reaction time. Preliminary biological evaluation of the prepared compounds reveals that some of the derivatives exhibited interesting anti-tubercular and anti-microbial activity towards the Mycobacterium tuberculosis H37Rv strain, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Candida albicans, The compound 3-Cyclohexyl-3,4-dihydro-2H-naphtho[2,1-e] [1, 3] oxazine (4d) exhibited an MIC value of 15.6 μg/mL, equivalent to that of the standard Fluconazole against Candida albicans. An improved MIC value of 15.6 μg/mL was displayed for Bacillus subtilis as compared to the standard value of Chloramphenicol and an MIC value of 1.57 μg/mL against Mycobacterium tuberculosis H37Rv, which is near-equivalent to that of Ethambutol. While for 4-(6-chloro-7-methyl-2H-benzo[e] [1, 3] oxazin-3(4H)-yl) benzonitrile (9b), it showed an MIC value of 31.25 μg/mL which is equivalent to that of the standard Chloramphenicol and an MIC value of 3.25 μg/mL against Mycobacterium tuberculosis H37Rv.