Discovery of 2-(4-cyano-3-trifluoromethylphenyl amino)-4-(4-quinazolinyloxy)-6-piperazinyl(piperidinyl)-s-triazines as potential antibacterial agents

A series of 2-(4-cyano-3-trifluoromethylphenyl amino)-4-(4-quinazolinyloxy)-6-piperazinyl(piperidinyl)-s-triazines have been synthesized in this study by a simple and efficient synthetic protocol. The synthetic route to final piperazinyl s-triazines involved two nucleophilic substitution reactions of 4-amino-2-trifluoromethyl-benzonitrile and 4-hydroxyquinazoline with 2,4,6-trichloro-1,3,5-triazine resulting in 2,4-disubstituted-6-chloro-1,3,5-triazine derivative to introduce the piperazinyl or piperidinyl functionality. The structures of the compounds were elucidated with the aid of IR, H-1 NMR, C-13 NMR, F-19 NMR spectroscopy, and elemental analysis. The antimicrobial activity of the compounds was tested against eight bacteria (Staphylococcus aureus MTCC 96, Bacillus cereus MTCC 619, Escherichia coli MTCC 739, Pseudomonas aeruginosa MTCC 741, Klebsiella pneumoniae MTCC 109, Salmonella typhi MTCC 733, Proteus vulgaris MTCC 1771, Shigella Flexneria MTCC 1457) and four fungi (Aspergillus niger MTCC 282, Aspergillus fumigatus MTCC 343, Aspergillus clavatus MTCC 1323, and Candida albicans MTCC 183). The title compounds were also investigated for their antituberculosis activity against MTB H37 R-V strain using BACTEC MGIT and L. J. agar dilution method. The bioassay results showed that compounds 5d, 5n, 5p, 5s, and 5t demonstrated 99% inhibition at the MIC of 6.25 mu g/ml, equivalent to standard drug pyrazinamide.