27-Demethoxy-27-hydroxyrifamycin S; 5,17,19,21,23-pentahydroxy-2,4,12,16,18,20,22-heptamethyl-2,7-(Epoxypentadeca[1,11,13]trienimino)naphtho[2,1-b]furan-1,6,9,11(2H)-tetrone 21-acetate ,27-Demethoxy-27-hydroxyrifamycin S; 5,17,19,21,23-pentahydroxy-2,4,12,16,18,20,22-heptamethyl-2,7-(Epoxypentadeca[1,11,13]trienimino)naphtho[2,1-b]furan-1,6,9,11(2H)-tetrone 21-acetate ,rifamycin