38123-27-2 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, 2,2-dibutyl-1-methylhydrazide BRN 5418833 NSC 144141 Rifamycin B dibutylmethylhydrazide Rifamycin, 4-O-(2-(2,2-dibutyl-1-methylhydrazino)-2-oxoethyl)- (9CI)