Production of a novel red pigment, rubrolone, by Streptomyces echinoruber sp. nov. II. Chemistry and structure elucidation.

Streptomyces echinoruber sp. nov. produces several red pigments. The major component, rubrolone, has been identified as 8(R),9(R),10(S),10a(R)-tetrahydro-9,10,10a,11-tetrahydroxy-3,8-dimethyl-1-propyl-6aH(S)-pyrano[2",3":5',4]furo[2',3':5,6]azuleno[2,3-c]pyridine-5,13-dione (1) by single crystal X-ray analysis of a suitable derivative. A second pigment, B, is probably structurally closely related.