SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF N-OXIDES OF QUINOXALINE DERIVATIVES SUBSTITUTED BY METHYL OR METHOXYL GROUPS IN THE BENZENE-RING

Synthesis of N-oxides of quinoxaline derivatives substituted at position 5 of the benzene ring with methoxy groups or at positions 6 and 7 with methyl groups was described. In experiments with Salmonella typhi, Proteus and Pseudomonas aeruginosa, introduction of methoxy groups at position 5 of the benzene ring significantly decreased or nullified antibacterial activity of di-N-oxides of quinoxaline containing methyl or acetoxy(hydroxy)methyl groups at positions 2 and 3. This reduction in antibacterial activity was also observed after introduction of methyl groups at positions 6 and 7 of the quinoxaline ring.