Environmentally benign synthesis and anti-mycobacterial evaluation of 9,10-dihydro-4-methyl-chromeno[8,7-<em>e</em>][1,3]oxazin-2(8<em>H</em>)-one derivatives

Abstract

In the present study, a series of 9,10-dihydro-4-methyl-chromeno[8,7-<em>e</em>][1,3]oxazin-2(8<em>H</em>)-one derivatives (<strong>4a-j</strong>) have been synthesized by using one-pot Mannich type condensation cyclization reaction of 7-hydroxy-4-methylcoumarin, formaldehyde and primary amines in water at 80-90°C. These products have been characterized using various spectroscopic techniques (¹H and ¹³C NMR, IR, and MS) followed by evaluation of their <em>in-vitro</em> anti-tubercular activity against <em>Mycobacterium tuberculosis</em> H37Rv. The compounds <strong>4g</strong> and <strong>4h</strong> display the lowest MIC of 5 µg/mL and offer a remarkable viability of HEK-293 cells at the highest test concentration (100 μg/mL) in toxicity assay.