The angucycline family of antibiotics is a large group of biologically active secondary metabolites of microbrial origin.'-3 Urdamycin B, a group member isolated from Streptomyces fradiae, is composed of a trisaccharide attached through a C-glycoside linkage to an angular quinone ring~ ystem.~ Careful acid hydrolysis of urdamycin B led to the loss of two sugars and the isolation of the aglycon urdamycinone B (1). 2a
