14487-05-9 NSC182391 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