Murayaanthraquinone, a hybrid benz[a]anthraquinone from a UV mutant of Streptomyces murayamaensis

An X-ray crystallographic analysis revealed that a new metabolite of Streptomyces murayamaensis, murayaanthraquinone, contains a 5-azo-16-oxo-dibenzo[b,k]chrysene ring system. This hexacyclic structure has been shown to be a hybrid derived from a benz[a]anthraquinone and a 3-amino-4-hydroxybenzoic acid.