((1,2,6,9-Tetrahydro-5,9,17,19,21-pentahydroxy-23-methoxy-2,4,12,16,18,20,22-heptamethyl-1,6,11-trioxo-2,7-(epoxypentadeca(1,11,13)trienimino)naphtho(2,1-b)furan-9-yl)oxy)acetic acid gamma-lactone, 21-acetate 14487-05-9 Acetic acid, ((1,2,6,9-tetrahydro-5,9,17,19,21-pentahydroxy-23-methoxy-2,4,12,16,18,20,22-heptamethyl-1,6,11-trioxo-2,7-(epoxypentadeca(1,11,13)trienimino)naphtho(2,1-b)furan-9-yl)oxy)-, gamma-lactone, 21-acetate EINECS 238-493-1 NSC 182391 Rifamycin O Rifamycin, 4-O-(carboxymethyl)-1-deoxy-1,4-dihydro-4-hydroxy-1-oxo-, gamma-lactone Rifomycin O Spiro(1,3-dioxolane-2,9'(6'H)-(2,7)(epoxypentadeca(1,11,13)trienimino)naphtho(2,1-b)furan)-1',4,6',11'(2'H)-tetrone, 5',17',19',21'-tetrahydroxy-23'-methoxy-2',4',12',16',18',20',22'-heptamethyl-, 21'-acetate