Novel benzothiazinone derivatives of formula (I) or a pharmaceutically acceptable salt or solvate 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 groupY = a bond, or a straight or branched C1-C4 alkylene group wherein either one of X or Y is a bond and the other is a C1-C4- alkylene group,Z = N or C,n = 1 or 2R1 = hydrogen, a straight or branched C1-C6 alkyl group, or a C3-C6 cycloalkyl group, which may be substituted with a group selected from F, Cl, Br, I or a C1-C4 alkoxy R2 = a phenyl group, a naphthyl group or a thienyl group, each of which may be unsubstituted or substituted with one or more substituent(s) which may be the same or different from each other, selected from the group consisting of F, Cl, Br, I, CN, NO2, or a straight or branched C1-C6 alkyl or phenyl group, which may be substituted with a group selected from F, Cl, Br, I, or C1-C4 alkoxy.
