Synonyms: Vertisporin,7',8'-didehydro-2',3'-epoxy-2',3'-dihydro-; Roritoxin B;Spiro[8H,21bH-3a,21a-(epoxyethano)-10,12-methano-17H,18H-furo[2',3':10,11]oxireno[8,9][1,6]dioxacyclohexadecino[3,4-d][1]benzopyran-11(12H),2'-oxirane]-8,20(20aH)-dione,2,3,10,10a,13a,16-hexahydro-2,3-dihydroxy-10a,15-dimethyl-,(3aR,10R,10aS,11S,12R,13aR,17aR,21aS,21bR)-[partial]-