Synthesis and Antimicrobial Activity of Branched Benzoxazinophenothiazines and their Derivatives

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.