38123-28-3 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-ethylhydrazide Rifamycin B dibutylethylhydrazide