STUDIES ON JUVENIMICIN, A NEW ANTIBIOTIC. II: ISOLATION, CHEMICAL CHARACTERIZATION AND STRUCTURES

A series of new macrolide antibiotics was isolated from the culture filtrate of Micromonospora chalcea var. izumensis. The fat-soluble basic complex consisted of eight components which were named juvenimicin A1-A4 and B1-B4. Juvenimicin A3 was found to be identical with rosamicin and the structures of four of the other components (JVM A2, A4, B1 and B3) have been elucidated. Juvenimicin A2 has a methyl group at position 6 instead of the formyl-methyl group of juvenimicin A3. Juvenimicin A4, B1 and B3 possess a hydroxyethyl group at position 6. Juvenimicin A4 and B1 differ from each other in the nature of the chromophore. Juvenimicin B3 differs from juvenimicin B1 in that a hydroxymethyl group is present at position 14 in the former.