Studies on mycotrienin antibiotics, a novel class of ansamycins. III. The isolation, characterization and structures of mycotrienols I and II.

Two minor components designated mycotrienols I and II which were concurrently produced with mycotrienins I and II by Streptomyces rishiriensis T-23 were isolated and characterized. Like mycotrienins I and II, mycotrienols I and II are also interconvertible via redox reaction and their structures have been established as depicted in 3 and 4 on the basis of 13C NMR evidence along with chemical degradation. The biological activities are discussed.