A series of 10a-phenylbenzo [b] indeno [1, 2-e][1, 4] thiazin-11 (10aH)-ones (3) has been synthesized and tested for their antimicrobial activity. The antimicrobial evaluation data indicated that compounds, 3b, 3d, 3k and 3m exhibited very promising antibacterial activity and the compounds 3b and 3k exhibited notable activity, almost comparable to penicillin for Staphylococcus aureus and Bacillus subtilis respectively. The derivatives 3g and 3l ...
