Studies on an antibiotic, albocycline VII. Minor components of albocycline

As an approach to the search for new potentially useful macrolide antibiotics, we explored the minor components of albocycline (ALB) from the culture broth of Streptomyces bruneogriseus. Eight minor components were isolated and their structures were confirmed as 1 approximately 8. Unexpectedly, they were not glycosidic compounds but only oxidation or reduction products of ALB. Three or four of them will serve as a useful intermediate to introduce amino sugar moiety into ALB skeleton.