Antimycobacterial 3-phenyl-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones and 3-phenyl-2H-1,3-benzoxazine-2,4(3H)-dithiones substituted on phenyl and benzoxazine moiety in position 6

A series of forty-five derivatives of 3-phenyl-4-thioxo-2H-1,3-benzoxazine-2(3H)-ones and forty-five derivatives of 3-phenyl-2H-1,3-benzoxazine-2,4(3H)-dithiones was synthesised. The compounds exhibited in-vitro activity against Mycobacterium tuberculosis, M. kansasii (two strains), and M. avium. The most active derivatives were more active than isonicotinhydrazide (INH). The quantitative relationships between the structure and antimycobacterial activity were calculated. The activity against M. tuberculosis increased with the lipophilicity of the substituents.