Synthesis and Antimicrobial Activity of New Derivatives of Angular Polycyclic Phenoxazine Ring System

Synthesis of angular polycyclic phenoxazine derivatives incorporating different phenols is reported in 30-99% yields. O-arylation of 6-chlorodibenzo[a,j] phenoxazin-5-one with a variety of electron-deficient, electron-neutral and electron-rich phenols under the catalytic palladium (II) acetate/t-BuXphos system furnished the compounds of interest. The highest yields were obtained when the intermediate was coupled with electron-rich phenols. IR, 1H-NMR, 13C-NMR and Mass spectra data, confirmed the structures of all the synthesized compounds. Study on the in vitro biological evaluation of the compounds against microorganisms revealed that they are potent antibacterial and antifungal agents, as they showed significant biological activity against Staphylococcus aureus, Streptococcus pneumonia, Escherichia coli, Salmonella typhi, klebsiella pneumonia, Pseudomonas aeruginasa, Basillus substilis, Candida albicans and Aspergillus niger.