Novel benzothiazinone derivatives of formula (I) or pharmaceutically acceptable salts or solvates thereof have been found to be effective against Mycobacterium tuberculosis strains and may thus be useful in the treatment of tuberculosis:whereinEWG (electron withdrawing group) = NO2 CN, CF3, F, Cl, Br, OCF3, OH, OR, OCHF2, COOR, wherein R is hydrogen or a straight or branched C1-C4 alkyl group,X = a bond or a straight or branched C1-C4 alkylene group which may be substituted with a group selected from F, Cl, Br, I or C1-C4 alkoxyY = hydrogen, a straight or branched C1-C4 alkyl group, OH or OR, wherein R is hydrogen or a straight or branched C1-C4 alkyl groupn = 0, 1 or 2R1, R2 = hydrogen or substituent(s) which may be the same or different from each other and are selected from the group consisting of D, F, Cl, Br, CF3, a straight or branched C1-C4 alkyl group, a phenyl group, OR, SR, NR3R4, wherein R, R3, R4 may be the same or different from each other and are hydrogen or a straight or branched C1-C4 alkyl group or a phenyl group.
