Sapurimycin, new antitumor antibiotic produced by Streptomyces. Structure determination

The structure of a new anthra-gamma-pyrone antitumor antibiotic sapurimycin was determined by the spectral studies of its methyl ester. Sapurimycin has the same anthra-gamma-pyrone skeleton as pluramycin, but is distinctly different because of the absence of sugars on the D ring and possessing a carboxylmethyl group on C-5.