13929-35-6 4-O-(Carboxymethyl)rifamycin Acetic acid, ((1,2-dihydro-5,6,17,19,21-pentahydroxy-23-methoxy-2,4,12,16,18,20,22-heptamethyl-1,11-dioxo-2,7-(epoxypentadeca(1,11,13)trienimino)naphtho(2,1-b)furan-9-yl)-oxy)-, 21-acetate EINECS 237-697-8 NCI 145-604 NSC 145604 Nacimycin Nancimycin RIFAMYCIN B Rifamycin, 4-O-(carboxymethyl)- Rifomycin B (6CI)