Synonyms: Emestrin;2H,8H,20H,22H-1,21-Epidithio-21,1-(iminomethano)-9,13:15,19-dimetheno-4,7,14-trioxa-22a-azacyclononadec[cd]azulene-8,22,26-trione,6a,22b-dihydro-2,16,20-trihydroxy-12-methoxy-25-methyl-,[1R-(1R*,2R*,6aS*,20S*,21R*,22bS*)]-; Emestrine;[1R-(1R*,2R*,6aS*,20S*,21R*,22bS*)]-6a,22b-Dihydro-2,16,20-trihydroxy-12-methoxy-25-methyl-2H,8H,20H,22H-1,21-epidithio-21,1-(iminomethano)-9,13:15,19-dimetheno-4,7,14-trioxa-22a-azacyclononadec[cd]azulene-8,22,26-trione