Early intermediates in the biosynthesis of ansamycins. II. Isolation and identification of proasamycin B-M1 and protorifamycin I-M1.

Early intermediates in the biosynthesis of ansamycins. II. Isolation and identification of proasamycin B-M1 and protorifamycin I-M1. 3-Hydroxyrifamycin S and further novel ansamycins from a recombinant strain R-21 of Nocardia mediterranei. Rifamycin Z, a novel ansamycin from a mutant of Nocardia mediterranea. Rifamycin G, a further product of Nocardia mediterranei metabolism. Biosynthetic origins of the oxygen atoms in the ansamycin antibiotics rifamycin B, O, and S Isolation of 11,12-<i>seco</i>-Rifamycin W Derivatives Reveals a Cleavage Pattern of the Rifamycin <i>Ansa</i> Chain The structures of macbecin I and II, new antitumor antibiotics Two novel ansamitocin analogs from <i>Actinosynnema pretiosum</i> Mycinamicins, new macrolide antibiotics. XI. Isolation and structure elucidation of a key intermediate in the biosynthesis of the mycinamicins, mycinamicin VIII. Studies on mycotrienin antibiotics, a novel class of ansamycins. III. The isolation, characterization and structures of mycotrienols I and II.