Synonyms: 2,7-(Epoxypentadeca[1,11,13]trien[1]yl[15]ylidenenitrilo)naphtho[2,1-b]furan-1,6,9(2H)-trione,5,17,19,21-tetrahydroxy-11,23-dimethoxy-2,4,12,16,18,20,22-heptamethyl-,21-acetate (7CI,8CI);2,7-(Epoxypentadeca[1,11,13]trien[1]yl[15]ylidenenitrilo)naphtho[2,1-b]furan,rifamycin deriv.; NSC 253937; Rifamycin S, imino-methyl ether