13929-40-3 BRN 5418443 Pyrrolidine, 1-(((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)acetyl)-, 21-acetate Rifamycin B pyrrolidide Rifamycin, 4-O-(2-oxo-2-(1-pyrrolidinyl)ethyl)- (9CI)