Simocyclinones, novel cytostatic angucyclinone antibiotics produced by Streptomyces antibioticus Tü 6040 II. Structure elucidation and biosynthesis.

The simocyclinones D4 (1) and D8 (2), members of a novel class of antibiotics, were isolated from the mycelial extract of Streptomyces antibioticus Tu 6040 and consist of angucyclinone, deoxysugar, octatetraene dicarboxylate and aminocoumarin structural elements. The structure elucidation was done by one and two dimensional NMR experiments, and other spectroscopic methods in combination with incorporation experiments using C-13 labelled precursors.