Anthramycin is a pyrrolobenzodiazepine antibiotic with antitumor activity. First derived from the thermophilic anctinomycete Streptomyces refuineus by M. D. Tendler and S Korman in the 1950s, it was first successfully synthesized in a laboratory setting by Leimgruber et al. in 1965. Due to the unstable nature of the chemical structure, characterization of the species was done on its epimer, anthrmycin-11-methyl-ether. This derivative can be formed by recrystallization of anthramycin from hot methanol.