The structure of efrotomycin.

The antibiotic efrotomycin (I), C59H88N2O20, was isolated from cultures of Nocardia lactamdurans as an amorphous yellow powder. Mass spectral and NMR analyses show that the compound is a glycoside of the known antibiotic aurodox (II), C44H62N2O12. Ozonolysis and hydrolysis of I produced the disaccharide V, 6-deoxy-4-O-(6-deoxy-2,4-di-O-methyl-alpha -L-mannopyranosyl)-3-O-methyl-beta-D-allopyranose. This disaccharide is attached to the 4-hydroxyl group of the hexahydropyran substructure of aurodox via a beta-linkage to C-1 of the allose.