The discovery, fermentation, isolation, and structure of antibiotic A33853 and its tetraacetyl derivative.

The structure of antibiotic A33853, isolated from the culture broth ofStreptomyces sp., NRRL 12068, is reported. The structure was deduced from an X-ray crystallographic study of its tetraacetyl derivative. Tetraacetyl A33853 is unique because it contains an anhydride moiety, an unexpected product from the reaction of A33853 with acetic anhydride and pyridine.