l-Proline-catalysed facile green protocol for the synthesis and antimycobacterial evaluation of [1,4]-thiazines

A series of ethyl 6-(4-chlorobenzoyl)-1,1-dioxo-3,5-diaryl-1,4-thiazinane-2-carboxylates was prepared in good yields (72-90%) from the reaction of ethyl 2-[(2-oxo-2-arylethyl)sulfonyl]acetate, substituted aromatic aldehydes and amines in presence of green catalyst, L-proline. These compounds were evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (MTB), multi-drug resistant M. tuberculosis (MDR-TB) and Mycobacterium smegmatis (MC(2)) using agar dilution method. Ethyl 6-(4-chlorobenzoyl)-3,5-di(4-nitrophenyl)-1,1-dioxo-1,4-thiazinane-2-carboxylate was found to be the most promising compound (MIC: 0.68 microM) active against MTB and MDR-TB.