Purification, structure determination, and antimicrobial activity of neutramycins B-G.

Neutramycins B-G were purified from a historical sample of neutramycin in our antibiotic collection. The structures of the compounds were solved by 2D NMR spectroscopic analysis. Four of the compounds (2-5) are probable biosynthetic intermediates or shunt metabolites of neutramycin biosynthesis, while two (6, 7) are likely to be degradation products. Only one intermediate (5) showed weak Gram-positive activity.