Kinamycin biosytheesis. Synthesis, detection, and incorporation of kinobscurinone, a benzo[b]fluorenone

The kinamycin antibiotics, derived from a benzo[a]anthraquinone precusor, were recently shown to be 5-diazobenzo[b]fluorene quinones. A 5-ketobenzo[b]fluorene quinone has been synthesized and shown to be present in Streptomyces murayamaensis fermentations, and a deuterium-labeled sample of this metabolite, kinobscurinone, has been incorporated biosynthetically into kinamycins C and D.