Antibacterial activities carbazoles

In 1993, Oki et al. isolated the novel carbazole antibiotics epocarbazolin A (258) and B (259) from the culture broth of Streptomyces anulatus T688-8 (230). They represent the first carbazole alkaloids with an epoxide moiety in a side chain, and are the epoxides corresponding to carbazomadurin A (256) and B (257). Epocarbazolin A (258) [oC + 75.0 (c 0.5, MeOH) and B (259) Mg -b 78.0 (c 0.5, MeOH) were obtained from Nature in optically active form. However, their absolute configuration is not known. These alkaloids showed potent 5-lipoxygenase inhibitory activity and weak antibacterial activity (230) (Scheme 2.63). 

Carbazoles are pharmaceutically important heterocycles, and are attractive targets for organic chemists. Carbazole alkaloids are natural products exhibiting antitumor, antibacterial, antimicrobial, and antiinflammatory activities. Some carbazole derivatives display photoconducting and semiconducting properties. The nucleophylic approach can be used for the synthesis of the carbazole core. For example, intramolecular cyclization of 2-(6-substituted-3-(Z)-hexene-l,5-diyne)anilines 3.702 was accomplished for the synthesis of 5-carbazoles 3.703 in 65-85% yield (Scheme 3.76) [331]. 

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