21240-38-0 9,4-(Epoxypentadeca(1,11,13)trienimino)-1H-benzofuro(5,4-g)indole-10,26(9H)-dione, 3-acetyl-5,6,16,18,20-pentahydroxy-14-methoxy-1,2,7,9,15,17,19,21,25-nonamethyl-, 16-acetate BRN 5402462 NCI 143-462 PR 14 Rifamycin II, 3'-acetyl-1',2'-dimethyl- Rifamycin PR 14