2,7-(Epoxypentadeca(1,11,13)trienimino)naphtho(2,1-b)furan-1,11(2H)-dione, 9-((2,5-dimethyl-1-pyrrolidinylcarbonyl)methoxy)-2,4,12,16,18,20,22-heptamethyl-23-methoxy-5,6,17,19,21-pentahydroxy-, 21-acetate 38123-17-0 BRN 5418591 NCI 143-439 Rifamycin B 2,5-dimethylpyrrolidide Rifamycin, 4-O-(2-(2,5-dimethyl-1-pyrrolidinyl)-2-oxoethyl)- (9CI)