Synthesis and Antimicrobial Activity of Branched Benzoxazinophenothiazines and their Derivatives
Abstract
The syntheses of benzoxazinophenothiazine was thoroughly explored. Condensation of 2,3-dichloro-1,4-naphthoquinone with 2-amino-4-nitrophenol, 4,5-diamino-6-hydroxypyrimidin-2-thiol and 2-amino-6-chlorophenol, respectively in alkaline medium yielded the intermediates: 6-chloro-10-nitrobenzo[a]phenoxazin-5-one(136), 11-amino-6-chloro-9-thiol-8,9-diazabenzo[a]phenoxazin-5-one (148) and 6,8-dichlorobenzo[a]phenoxazin-5-one (160). Further treatment of the intermediates with 2-aminothiophenol and 3-amino-6-methoxypyridin-2-thiol gave the complex derivatives: 14-nitrobenzo[a][1,4]benzoxazino[3,2-c]phenothiazine (137), 15-amino-13-thiol-12,14-diazabenzo[a][1,4]benzoxazino[3,2-c]phenothiazine (149) and 12-chloro-9-methoxy-8-azabenzo[a][1,4]benzoxazino[3,2-c]phenothiazine (161). The compounds were characterized by UV/Visible, FT-IR, (1H and 13C-NMR) spectroscopy and elemental analysis. The synthesized compounds were screened against eight (8) micro-organisms viz: Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Kebsiella pneumonia, Asperigellus niger and Candida albicans using agar-cup diffusion method. The results showed that the complex derivatives were significantly active against the micro-organisms when compared to antibacterial and anti-fungal drugs.
