Salicylanilides and 3-phenyl-2H-1,3-benzoxazine-2,4(3H)-diones are strong antimycobacterial substances which can be considered to be potential antituberculotics. In order to be able to verify the prognostics of the relationships between the structure and antimycobacterial activity, the series of previously evaluated substances was extended to include 4´-ethoxycarbonylsalicylanilide, 4´-tri- fluoromethylsalicylanilide, 4´-cyanidosalicylanilide, 4´-thiocarbamoylsalicylanilide, 3-(4-ethoxycar- bonylphenyl)-2H-1,3-benzoxazine-2,4(3H)-dione, 3-(4-trifluoromethylphenyl)-2H-1,3-benzoxazine- -2,4(3H)-dione, and 3-(4-cyanidophenyl)-2H-1,3-benzoxazine-2,4-(3H)-dione. The substances were evaluated against Mycobacterium tuberculosis, M. kansasii, and M. avium. In harmony with the previous study (see ref. 1), antimycobacterial activity increased with increasing lipophilicity and electron-acceptor properties of substituents. As the values of regression coefficients were not substantially changed after the complementation of the group, the present authors consider the problem under study to be solved.

        Key words: salicylanilides - benzoxazine -Œ mycobacterium - tuberculostatic - QSAR